diff --git a/StructureHelper/Infrastructure/Enums/MaterialType.cs b/StructureHelper/Infrastructure/Enums/MaterialType.cs
index 19b6550..21a6abb 100644
--- a/StructureHelper/Infrastructure/Enums/MaterialType.cs
+++ b/StructureHelper/Infrastructure/Enums/MaterialType.cs
@@ -8,10 +8,11 @@ namespace StructureHelper.Infrastructure.Enums
 {
     internal enum MaterialType
     {
-        Concrete,
-        Reinforcement,
-        Elastic,
-        CarbonFiber,
-        GlassFiber
+        Concrete = 0,
+        Reinforcement = 1,
+        Elastic = 2,
+        CarbonFiber = 3,
+        GlassFiber = 4,
+        Steel = 5
     }
 }
diff --git a/StructureHelper/Infrastructure/UI/Resources/Materials.xaml b/StructureHelper/Infrastructure/UI/Resources/Materials.xaml
index 72b5407..8577d54 100644
--- a/StructureHelper/Infrastructure/UI/Resources/Materials.xaml
+++ b/StructureHelper/Infrastructure/UI/Resources/Materials.xaml
@@ -163,4 +163,12 @@
         </Grid>
     </DataTemplate>
 
+    <DataTemplate  x:Key="SteelMaterial">
+        <StackPanel>
+            <ContentControl ContentTemplate="{StaticResource LibraryMaterial}" Content="{Binding}"/>
+            <Button Content="Show Safety Factors" Command="{Binding ShowSafetyFactors}"/>
+            <ContentControl ContentTemplate="{StaticResource MaterialSafetyFactors}" Content="{Binding SafetyFactors}"/>
+        </StackPanel>
+    </DataTemplate>
+
 </ResourceDictionary>
\ No newline at end of file
diff --git a/StructureHelper/Libraries/LoaderCalculator.dll b/StructureHelper/Libraries/LoaderCalculator.dll
index 41f80ee..3b78545 100644
Binary files a/StructureHelper/Libraries/LoaderCalculator.dll and b/StructureHelper/Libraries/LoaderCalculator.dll differ
diff --git a/StructureHelper/Windows/MainWindow/CrossSections/CrossSectionView.xaml b/StructureHelper/Windows/MainWindow/CrossSections/CrossSectionView.xaml
index 37b29ef..d2abe13 100644
--- a/StructureHelper/Windows/MainWindow/CrossSections/CrossSectionView.xaml
+++ b/StructureHelper/Windows/MainWindow/CrossSections/CrossSectionView.xaml
@@ -244,6 +244,11 @@
                                                 <Image Style="{StaticResource ButtonImage16}" Source="/Windows/MainWindow/RFMaterial32.png" />
                                             </MenuItem.Icon>
                                         </MenuItem>
+                                        <MenuItem Header="Steel" Command="{Binding Add}" CommandParameter="{x:Static enums:MaterialType.Steel}">
+                                            <MenuItem.Icon>
+                                                <Image Style="{StaticResource ButtonImage16}" Source="/Windows/MainWindow/RFMaterial32.png" />
+                                            </MenuItem.Icon>
+                                        </MenuItem>
                                         <MenuItem Header="Elastic" Command="{Binding Add}" CommandParameter="{x:Static enums:MaterialType.Elastic}">
                                             <MenuItem.Icon>
                                                 <Image Style="{StaticResource ButtonImage16}" Source="/Windows/MainWindow/ElasticMaterial32.png" />
diff --git a/StructureHelper/Windows/MainWindow/Materials/HeadMaterialView.xaml.cs b/StructureHelper/Windows/MainWindow/Materials/HeadMaterialView.xaml.cs
index e60c365..33adab5 100644
--- a/StructureHelper/Windows/MainWindow/Materials/HeadMaterialView.xaml.cs
+++ b/StructureHelper/Windows/MainWindow/Materials/HeadMaterialView.xaml.cs
@@ -5,17 +5,9 @@ using StructureHelperCommon.Models.Materials;
 using StructureHelperLogics.Models.Materials;
 using System;
 using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
 using System.Windows;
 using System.Windows.Controls;
 using System.Windows.Data;
-using System.Windows.Documents;
-using System.Windows.Input;
-using System.Windows.Media;
-using System.Windows.Media.Imaging;
-using System.Windows.Shapes;
 
 namespace StructureHelper.Windows.MainWindow.Materials
 {
@@ -70,6 +62,10 @@ namespace StructureHelper.Windows.MainWindow.Materials
             {
                 SetElasticMaterial();
             }
+            else if (helperMaterial is ISteelLibMaterial)
+            {
+                SetSteelMaterial();
+            }
             else
             {
                 string errorString = ErrorStrings.ObjectTypeIsUnknown + $". Expected: {typeof(IHelperMaterial)}, but was: {helperMaterial.GetType()}";
@@ -77,6 +73,16 @@ namespace StructureHelper.Windows.MainWindow.Materials
             }
         }
 
+        private void SetSteelMaterial()
+        {
+            templateName = "SteelMaterial";
+            var binding = new Binding
+            {
+                Source = viewModel.HelperMaterialViewModel
+            };
+            bindings.Add(templateName, binding);
+        }
+
         private void SetContentControls()
         {
             foreach (var item in bindings)
diff --git a/StructureHelper/Windows/MainWindow/Materials/HeadMaterialViewModel.cs b/StructureHelper/Windows/MainWindow/Materials/HeadMaterialViewModel.cs
index 3fc44d7..bc46ecd 100644
--- a/StructureHelper/Windows/MainWindow/Materials/HeadMaterialViewModel.cs
+++ b/StructureHelper/Windows/MainWindow/Materials/HeadMaterialViewModel.cs
@@ -73,6 +73,10 @@ namespace StructureHelper.Windows.ViewModels.Materials
             {
                 helperMaterialViewModel = new LibMaterialViewModel<IReinforcementMaterialEntity>(reinforcementMaterial);
             }
+            else if (helperMaterial is ISteelLibMaterial steelMaterial)
+            {
+                helperMaterialViewModel = new LibMaterialViewModel<ISteelMaterialEntity>(steelMaterial);
+            }
             else if (helperMaterial is IElasticMaterial elasticMaterial)
             {
                 if (helperMaterial is IFRMaterial fRMaterial)
diff --git a/StructureHelper/Windows/MainWindow/Materials/MaterialsViewModel.cs b/StructureHelper/Windows/MainWindow/Materials/MaterialsViewModel.cs
index ff310c7..a3cab89 100644
--- a/StructureHelper/Windows/MainWindow/Materials/MaterialsViewModel.cs
+++ b/StructureHelper/Windows/MainWindow/Materials/MaterialsViewModel.cs
@@ -7,6 +7,7 @@ using StructureHelperCommon.Infrastructures.Exceptions;
 using StructureHelperLogics.Models.CrossSections;
 using StructureHelperLogics.Models.Materials;
 using StructureHelperLogics.NdmCalculations.Primitives;
+using System;
 using System.Linq;
 using System.Windows.Forms;
 using System.Windows.Input;
@@ -47,9 +48,18 @@ namespace StructureHelper.Windows.ViewModels.Materials
             else if (parameterType == MaterialType.Elastic) { AddElastic(); }
             else if (parameterType == MaterialType.CarbonFiber) { AddCarbonFiber(); }
             else if (parameterType == MaterialType.GlassFiber) { AddGlassFiber(); }
+            else if (parameterType == MaterialType.Steel) { AddSteel(); }
             else throw new StructureHelperException(ErrorStrings.ObjectTypeIsUnknown + $". Expected: {typeof(MaterialType)}, Actual type: {nameof(parameterType)}");
             base.AddMethod(parameter);
         }
+
+        private void AddSteel()
+        {
+            var material = HeadMaterialFactory.GetHeadMaterial(HeadmaterialType.SteelS345);
+            material.Name = "New Steel";
+            NewItem = material;
+        }
+
         public override void DeleteMethod(object parameter)
         {
             var primitives = repository.Primitives;
diff --git a/StructureHelperCommon/Infrastructures/Enums/CodeTypes.cs b/StructureHelperCommon/Infrastructures/Enums/CodeTypes.cs
index fa1d122..c8a1a8b 100644
--- a/StructureHelperCommon/Infrastructures/Enums/CodeTypes.cs
+++ b/StructureHelperCommon/Infrastructures/Enums/CodeTypes.cs
@@ -5,5 +5,6 @@
         SP63_2018,
         EuroCode_2_1990,
         SP164_2014,
+        SP16_2017
     }
 }
diff --git a/StructureHelperCommon/Models/Codes/Factories/CodeFactory.cs b/StructureHelperCommon/Models/Codes/Factories/CodeFactory.cs
index aaf9f6b..fd6caaf 100644
--- a/StructureHelperCommon/Models/Codes/Factories/CodeFactory.cs
+++ b/StructureHelperCommon/Models/Codes/Factories/CodeFactory.cs
@@ -1,9 +1,6 @@
 using StructureHelperCommon.Infrastructures.Enums;
 using System;
 using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
 
 namespace StructureHelperCommon.Models.Codes.Factories
 {
@@ -48,6 +45,12 @@ namespace StructureHelperCommon.Models.Codes.Factories
                 FullName = "Reinforced steel low-relaxation 7-wire strands. Specifications"
             };
             codeEntities.Add(codeEntity);
+            codeEntity = new CodeEntity(new Guid("2A43EDEC-8B1B-4B0B-B2E1-B7507518B8E7"), natSystem)
+            {
+                Name = "GOST 27772-2021",
+                FullName = "Rolled products for structural steel constructions.General specifications"
+            };
+            codeEntities.Add(codeEntity); 
             return (codeEntities, codeRevisions);
         }
 
diff --git a/StructureHelperCommon/Models/Codes/ICodeEntity.cs b/StructureHelperCommon/Models/Codes/ICodeEntity.cs
index 82e9692..fef2b19 100644
--- a/StructureHelperCommon/Models/Codes/ICodeEntity.cs
+++ b/StructureHelperCommon/Models/Codes/ICodeEntity.cs
@@ -1,10 +1,5 @@
 using StructureHelperCommon.Infrastructures.Enums;
 using StructureHelperCommon.Infrastructures.Interfaces;
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
 
 namespace StructureHelperCommon.Models.Codes
 {
diff --git a/StructureHelperCommon/Models/Materials/Factories/MaterialLogicsFactory.cs b/StructureHelperCommon/Models/Materials/Factories/MaterialLogicsFactory.cs
index a736738..dc4052b 100644
--- a/StructureHelperCommon/Models/Materials/Factories/MaterialLogicsFactory.cs
+++ b/StructureHelperCommon/Models/Materials/Factories/MaterialLogicsFactory.cs
@@ -1,6 +1,7 @@
 using LoaderCalculator.Data.Materials.MaterialBuilders;
 using StructureHelperCommon.Infrastructures.Enums;
 using StructureHelperCommon.Models.Materials;
+using StructureHelperCommon.Models.Materials.Libraries;
 using System;
 using System.Collections.Generic;
 using System.Linq;
@@ -33,6 +34,12 @@ namespace StructureHelperCommon.Models.Materials
                     Name = "Curve",
                     DiagramType = DiagramType.Curve
                 },
+                new SteelMaterialBuilderLogic(new Guid("C3BE4B92-DC61-43CF-A632-ADFC1AA57D8F"))
+                {
+                    MaterialType = MaterialTypes.Steel,
+                    Name="Triplelinear",
+                    DiagramType = DiagramType.TripleLinear
+                },
             };
             return items;
         }
diff --git a/StructureHelperCommon/Models/Materials/IMaterialLogicOptions.cs b/StructureHelperCommon/Models/Materials/IMaterialLogicOptions.cs
index a979cbf..243f4c2 100644
--- a/StructureHelperCommon/Models/Materials/IMaterialLogicOptions.cs
+++ b/StructureHelperCommon/Models/Materials/IMaterialLogicOptions.cs
@@ -1,10 +1,6 @@
 using StructureHelperCommon.Infrastructures.Enums;
 using StructureHelperCommon.Models.Materials.Libraries;
-using System;
 using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
 
 namespace StructureHelperCommon.Models.Materials
 {
diff --git a/StructureHelperCommon/Models/Materials/Libraries/ConcreteMaterialEntity.cs b/StructureHelperCommon/Models/Materials/Libraries/ConcreteMaterialEntity.cs
index 406fcdd..bdeb737 100644
--- a/StructureHelperCommon/Models/Materials/Libraries/ConcreteMaterialEntity.cs
+++ b/StructureHelperCommon/Models/Materials/Libraries/ConcreteMaterialEntity.cs
@@ -11,16 +11,11 @@ namespace StructureHelperCommon.Models.Materials.Libraries
         public ICodeEntity Code { get; set; }
         public string Name { get; set; }
         public double MainStrength { get; set; }
-        public double InitModulus { get; set; }
+        public double InitialModulus { get; set; }
 
         public ConcreteMaterialEntity(Guid id)
         {
             Id = id;
         }
-
-        public void Save()
-        {
-            throw new NotImplementedException();
-        }
     }
 }
diff --git a/StructureHelperCommon/Models/Materials/Libraries/Factories/FRFactorsFactory.cs b/StructureHelperCommon/Models/Materials/Libraries/Factories/FRFactorsFactory.cs
index 107e08e..aea85ec 100644
--- a/StructureHelperCommon/Models/Materials/Libraries/Factories/FRFactorsFactory.cs
+++ b/StructureHelperCommon/Models/Materials/Libraries/Factories/FRFactorsFactory.cs
@@ -1,10 +1,5 @@
 using StructureHelperCommon.Infrastructures.Enums;
 using StructureHelperCommon.Infrastructures.Exceptions;
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
 
 namespace StructureHelperCommon.Models.Materials.Libraries
 {
diff --git a/StructureHelperCommon/Models/Materials/Libraries/Factories/LibMaterialFactory.cs b/StructureHelperCommon/Models/Materials/Libraries/Factories/LibMaterialFactory.cs
index 05b13fa..193ca0e 100644
--- a/StructureHelperCommon/Models/Materials/Libraries/Factories/LibMaterialFactory.cs
+++ b/StructureHelperCommon/Models/Materials/Libraries/Factories/LibMaterialFactory.cs
@@ -17,6 +17,7 @@ namespace StructureHelperCommon.Models.Materials.Libraries
             {
                 libMaterials.AddRange(GetConcreteSP63());
                 libMaterials.AddRange(GetReinforcementSP63());
+                libMaterials.AddRange(GetSteelSP16());
             }
             else if (ProgramSetting.NatSystem == NatSystems.EU)
             {
@@ -30,6 +31,97 @@ namespace StructureHelperCommon.Models.Materials.Libraries
             return libMaterials;
         }
 
+        private static IEnumerable<ILibMaterialEntity> GetSteelSP16()
+        {
+            var codeType = CodeTypes.SP16_2017;
+            List<ILibMaterialEntity> libMaterials = new List<ILibMaterialEntity>();
+            libMaterials.AddRange(AddGOST2772(codeType));
+            return libMaterials;
+        }
+
+        private static IEnumerable<ILibMaterialEntity> AddGOST2772(CodeTypes codeType)
+        {
+            var code = ProgramSetting.CodesList
+    .Where(x => x.Name == "GOST 27772-2021")
+    .Single();
+            List<ILibMaterialEntity> range = new List<ILibMaterialEntity>()
+            {
+                new SteelMaterialEntity(new Guid("14F7EEA1-E924-42A1-928A-076BC8EE34A8"))
+                {
+                    CodeType = codeType,
+                    Code = code,
+                    Name = "S245",
+                    PropertyType = SteelDiagramPropertyType.S245,
+                    InitialModulus = 2.06e11d,
+                    MainStrength = 245e6
+                },
+                new SteelMaterialEntity(new Guid("69142AEF-BCC4-409A-8BAD-90390143516E"))
+                {
+                    CodeType = codeType,
+                    Code = code,
+                    Name = "S255",
+                    PropertyType = SteelDiagramPropertyType.S245,
+                    InitialModulus = 2.06e11d,
+                    MainStrength = 255e6
+                },
+                new SteelMaterialEntity(new Guid("BAD0A2B6-CF02-4554-891D-BB34FC3B2430"))
+                {
+                    CodeType = codeType,
+                    Code = code,
+                    Name = "S345",
+                    PropertyType = SteelDiagramPropertyType.S345,
+                    InitialModulus = 2.0e11d,
+                    MainStrength = 345e6
+                },
+                new SteelMaterialEntity(new Guid("C97AE177-872B-4B77-BCF6-6519AAAE1D54"))
+                {
+                    CodeType = codeType,
+                    Code = code,
+                    Name = "S355",
+                    PropertyType = SteelDiagramPropertyType.S345,
+                    InitialModulus = 2.0e11d,
+                    MainStrength = 355e6
+                },
+                new SteelMaterialEntity(new Guid("73700688-08BA-4A35-8BE0-26CD971FE73F"))
+                {
+                    CodeType = codeType,
+                    Code = code,
+                    Name = "S390",
+                    PropertyType = SteelDiagramPropertyType.S390,
+                    InitialModulus = 2.0e11d,
+                    MainStrength = 390e6
+                },
+                new SteelMaterialEntity(new Guid("39C0A796-9031-444C-BD3A-FFB236C9C85C"))
+                {
+                    CodeType = codeType,
+                    Code = code,
+                    Name = "S440",
+                    PropertyType = SteelDiagramPropertyType.S440,
+                    InitialModulus = 2.0e11d,
+                    MainStrength = 440e6
+                },
+                new SteelMaterialEntity(new Guid("7EF0525A-9965-4C8E-B15B-F7BE493382D0"))
+                {
+                    CodeType = codeType,
+                    Code = code,
+                    Name = "S550",
+                    PropertyType = SteelDiagramPropertyType.S550,
+                    InitialModulus = 2.0e11d,
+                    MainStrength = 550e6
+                },
+                new SteelMaterialEntity(new Guid("C3BE4B92-DC61-43CF-A632-ADFC1AA57D8F"))
+                {
+                    CodeType = codeType,
+                    Code = code,
+                    Name = "S590",
+                    PropertyType = SteelDiagramPropertyType.S550,
+                    InitialModulus = 2.0e11d,
+                    MainStrength = 590e6
+                },
+            };
+            return range;
+        }
+
         private static IEnumerable<ILibMaterialEntity> GetConcreteEurocode()
         {
             ICodeEntity code = ProgramSetting.CodesList.Where(x => x.Name == "EuroCode2-1990").Single();
@@ -260,7 +352,7 @@ namespace StructureHelperCommon.Models.Materials.Libraries
                     CodeType = codeType,
                     Code = code,
                     Name = "A240",
-                    InitModulus = 2e11d,
+                    InitialModulus = 2e11d,
                     MainStrength = 240e6d
                 },
                 new ReinforcementMaterialEntity(new Guid("ea422282-3465-433c-9b93-c5bbfba5a904"))
@@ -268,7 +360,7 @@ namespace StructureHelperCommon.Models.Materials.Libraries
                     CodeType = codeType,
                     Code = code,
                     Name = "A400",
-                    InitModulus = 2e11d,
+                    InitialModulus = 2e11d,
                     MainStrength = 390e6d
                 },
                 new ReinforcementMaterialEntity(new Guid("045b54b1-0bbf-41fd-a27d-aeb20f600bb4"))
@@ -276,7 +368,7 @@ namespace StructureHelperCommon.Models.Materials.Libraries
                     CodeType = codeType,
                     Code = code,
                     Name = "A500",
-                    InitModulus = 2e11d,
+                    InitialModulus = 2e11d,
                     MainStrength = 500e6d
                 },
                 new ReinforcementMaterialEntity(new Guid("e3cfc6fb-fbd0-47dd-ab4a-79c030704acf"))
@@ -284,7 +376,7 @@ namespace StructureHelperCommon.Models.Materials.Libraries
                     CodeType = codeType,
                     Code = code,
                     Name = "A600",
-                    InitModulus = 2e11d,
+                    InitialModulus = 2e11d,
                     MainStrength = 600e6d
                 },
                 new ReinforcementMaterialEntity(new Guid("6f0882ef-53bf-464e-acf7-da421a43a825"))
@@ -292,7 +384,7 @@ namespace StructureHelperCommon.Models.Materials.Libraries
                     CodeType = codeType,
                     Code = code,
                     Name = "A800",
-                    InitModulus = 2e11d,
+                    InitialModulus = 2e11d,
                     MainStrength = 800e6d
                 },
                 new ReinforcementMaterialEntity(new Guid("509fbaae-a3de-43c2-aae6-33387908dc43"))
@@ -300,7 +392,7 @@ namespace StructureHelperCommon.Models.Materials.Libraries
                     CodeType = codeType,
                     Code = code,
                     Name = "A1000",
-                    InitModulus = 2e11d,
+                    InitialModulus = 2e11d,
                     MainStrength = 1000e6d
                 }
             };
@@ -318,7 +410,7 @@ namespace StructureHelperCommon.Models.Materials.Libraries
                     CodeType = codeType,
                     Code = code,
                     Name = "K1400/1670",
-                    InitModulus = 1.95e11d,
+                    InitialModulus = 1.95e11d,
                     MainStrength = 1400e6
                 },
                 new ReinforcementMaterialEntity(new Guid("93c48a27-ab37-4bd2-aeb8-2a7247e74a1b"))
@@ -326,7 +418,7 @@ namespace StructureHelperCommon.Models.Materials.Libraries
                     CodeType = codeType,
                     Code = code,
                     Name = "K1500/1770",
-                    InitModulus = 1.95e11d,
+                    InitialModulus = 1.95e11d,
                     MainStrength = 1500e6
                 },
                 new ReinforcementMaterialEntity(new Guid("6e0df35e-4839-4cf1-9182-c7ad7f81a548"))
@@ -334,7 +426,7 @@ namespace StructureHelperCommon.Models.Materials.Libraries
                     CodeType = codeType,
                     Code = code,
                     Name = "K1600/1860",
-                    InitModulus = 1.95e11d,
+                    InitialModulus = 1.95e11d,
                     MainStrength = 1600e6
                 },
                 new ReinforcementMaterialEntity(new Guid("29d7ef1b-bd30-471e-af0e-8b419eb9f043"))
@@ -342,7 +434,7 @@ namespace StructureHelperCommon.Models.Materials.Libraries
                     CodeType = codeType,
                     Code = code,
                     Name = "K1700/1960",
-                    InitModulus = 1.95e11d,
+                    InitialModulus = 1.95e11d,
                     MainStrength = 1700e6
                 },
                 new ReinforcementMaterialEntity(new Guid("494b959f-0194-4f02-9dcf-ff313c5e352b"))
@@ -350,7 +442,7 @@ namespace StructureHelperCommon.Models.Materials.Libraries
                     CodeType = codeType,
                     Code = code,
                     Name = "K1800/2060",
-                    InitModulus = 1.95e11d,
+                    InitialModulus = 1.95e11d,
                     MainStrength = 1800e6
                 },
                 new ReinforcementMaterialEntity(new Guid("02031332-fe1e-456d-b339-143eb9ca8293"))
@@ -358,7 +450,7 @@ namespace StructureHelperCommon.Models.Materials.Libraries
                     CodeType = codeType,
                     Code = code,
                     Name = "K1900/2160",
-                    InitModulus = 1.95e11d,
+                    InitialModulus = 1.95e11d,
                     MainStrength = 1900e6
                 }
             };
diff --git a/StructureHelperCommon/Models/Materials/Libraries/Factories/SteelDiagramPropertyFactory.cs b/StructureHelperCommon/Models/Materials/Libraries/Factories/SteelDiagramPropertyFactory.cs
new file mode 100644
index 0000000..2947c2b
--- /dev/null
+++ b/StructureHelperCommon/Models/Materials/Libraries/Factories/SteelDiagramPropertyFactory.cs
@@ -0,0 +1,97 @@
+using StructureHelperCommon.Infrastructures.Exceptions;
+using StructureHelperCommon.Models.Forces.Logics;
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace StructureHelperCommon.Models.Materials.Libraries
+{
+    public enum SteelDiagramPropertyType
+    {
+        S245 = 0, //S245, S255
+        S345 = 1, //S345, S345K, S355, S355-1, S355-P
+        S390 = 2, //S390, S390-1
+        S440 = 3, //S440
+        S550 = 4, //S550, S590
+    }
+    public static class SteelDiagramPropertyFactory
+    {
+        public static ISteelDiagramRelativeProperty GetProperty(SteelDiagramPropertyType type)
+        {
+            if (type == SteelDiagramPropertyType.S245)
+            {
+                SteelDiagramRelativeProperty property = new()
+                {
+                    StrainOfProportionality = 0.8,
+                    StrainOfStartOfYielding = 1.7,
+                    StrainOfEndOfYielding = 14.0,
+                    StrainOfUltimateStrength = 141.6,
+                    StrainOfFracture = 251,
+                    StressOfUltimateStrength = 1.653,
+                    StressOfFracture = 1.35
+                };
+                return property;
+            }
+            else if (type == SteelDiagramPropertyType.S345)
+            {
+                SteelDiagramRelativeProperty property = new()
+                {
+                    StrainOfProportionality = 0.8,
+                    StrainOfStartOfYielding = 1.7,
+                    StrainOfEndOfYielding = 16.0,
+                    StrainOfUltimateStrength = 88.3,
+                    StrainOfFracture = 153,
+                    StressOfUltimateStrength = 1.415,
+                    StressOfFracture = 1.26
+                };
+                return property;
+            }
+            else if (type == SteelDiagramPropertyType.S390)
+            {
+                SteelDiagramRelativeProperty property = new()
+                {
+                    StrainOfProportionality = 0.9,
+                    StrainOfStartOfYielding = 1.7,
+                    StrainOfEndOfYielding = 17.0,
+                    StrainOfUltimateStrength = 67.1,
+                    StrainOfFracture = 115,
+                    StressOfUltimateStrength = 1.345,
+                    StressOfFracture = 1.23
+                };
+                return property;
+            }
+            else if (type == SteelDiagramPropertyType.S440)
+            {
+                SteelDiagramRelativeProperty property = new()
+                {
+                    StrainOfProportionality = 0.9,
+                    StrainOfStartOfYielding = 1.7,
+                    StrainOfEndOfYielding = 17.0,
+                    StrainOfUltimateStrength = 49.6,
+                    StrainOfFracture = 87.2,
+                    StressOfUltimateStrength = 1.33,
+                    StressOfFracture = 1.20
+                };
+                return property;
+            }
+            else if (type == SteelDiagramPropertyType.S550)
+            {
+                SteelDiagramRelativeProperty property = new()
+                {
+                    StrainOfProportionality = 0.9,
+                    StrainOfStartOfYielding = 1.7,
+                    StrainOfEndOfYielding = 18.0,
+                    StrainOfUltimateStrength = 26.2,
+                    StrainOfFracture = 51.1,
+                    StressOfUltimateStrength = 1.16,
+                    StressOfFracture = 1.10
+                };
+                return property;
+            }
+            else
+            {
+                throw new StructureHelperException(ErrorStrings.ObjectTypeIsUnknownObj(type));
+            }
+        }
+    }
+}
diff --git a/StructureHelperCommon/Models/Materials/Libraries/FiberMaterialEntity.cs b/StructureHelperCommon/Models/Materials/Libraries/FiberMaterialEntity.cs
deleted file mode 100644
index a256a87..0000000
--- a/StructureHelperCommon/Models/Materials/Libraries/FiberMaterialEntity.cs
+++ /dev/null
@@ -1,32 +0,0 @@
-using StructureHelperCommon.Infrastructures.Enums;
-using StructureHelperCommon.Models.Codes;
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
-
-namespace StructureHelperCommon.Models.Materials.Libraries
-{
-    internal class FiberMaterialEntity : IFiberMaterialEntity
-    {
-        ///<inheritdoc/>
-        public Guid Id { get; }
-        public CodeTypes CodeType { get; }
-        public ICodeEntity Code { get; set; }
-        public string Name { get; }
-        ///<inheritdoc/>
-        public double InitModulus { get; set; }
-        ///<inheritdoc/>
-        public double MainStrength { get; }
-        public FiberMaterialEntity(Guid id)
-        {
-            Id = id;
-            Name = "";
-        }
-        public void Save()
-        {
-            throw new NotImplementedException();
-        }
-    }
-}
diff --git a/StructureHelperCommon/Models/Materials/Libraries/IFiberMaterialEntity.cs b/StructureHelperCommon/Models/Materials/Libraries/IFiberMaterialEntity.cs
deleted file mode 100644
index aadb084..0000000
--- a/StructureHelperCommon/Models/Materials/Libraries/IFiberMaterialEntity.cs
+++ /dev/null
@@ -1,16 +0,0 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
-
-namespace StructureHelperCommon.Models.Materials.Libraries
-{
-    public interface IFiberMaterialEntity : ILibMaterialEntity
-    {
-        /// <summary>
-        /// Modulus of elasticity, Pa
-        /// </summary>
-        double InitModulus { get; set; }
-    }
-}
diff --git a/StructureHelperCommon/Models/Materials/Libraries/ILibMaterialEntity.cs b/StructureHelperCommon/Models/Materials/Libraries/ILibMaterialEntity.cs
index 459dc70..70dde0b 100644
--- a/StructureHelperCommon/Models/Materials/Libraries/ILibMaterialEntity.cs
+++ b/StructureHelperCommon/Models/Materials/Libraries/ILibMaterialEntity.cs
@@ -12,7 +12,7 @@ namespace StructureHelperCommon.Models.Materials.Libraries
         /// <summary>
         /// Initial Young's Modulus, Pa
         /// </summary>
-        double InitModulus { get; set; }
+        double InitialModulus { get; set; }
         /// <summary>
         /// Strength of material, Pa
         /// </summary>
diff --git a/StructureHelperCommon/Models/Materials/Libraries/ISteelDiagramAbsoluteProperty.cs b/StructureHelperCommon/Models/Materials/Libraries/ISteelDiagramAbsoluteProperty.cs
new file mode 100644
index 0000000..4c642e0
--- /dev/null
+++ b/StructureHelperCommon/Models/Materials/Libraries/ISteelDiagramAbsoluteProperty.cs
@@ -0,0 +1,22 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace StructureHelperCommon.Models.Materials.Libraries
+{
+    public interface ISteelDiagramAbsoluteProperty : ISteelDiagramProperty
+    {
+        /// <summary>
+        /// Initial modulus of elasticity (Young's modulus), Pa
+        /// </summary>
+        double InitialYoungsModulus { get; set; }
+        /// <summary>
+        /// Stress of yelding, Pa
+        /// </summary>
+        double BaseStrength { get; set; }
+        /// <summary>
+        /// Stress at point of limit of proportionality, Pa
+        /// </summary>
+        double StressOfProportionality { get; set; }
+    }
+}
diff --git a/StructureHelperCommon/Models/Materials/Libraries/ISteelDiagramProperty.cs b/StructureHelperCommon/Models/Materials/Libraries/ISteelDiagramProperty.cs
new file mode 100644
index 0000000..7566c3a
--- /dev/null
+++ b/StructureHelperCommon/Models/Materials/Libraries/ISteelDiagramProperty.cs
@@ -0,0 +1,34 @@
+namespace StructureHelperCommon.Models.Materials.Libraries
+{
+    public interface ISteelDiagramProperty
+    {
+        /// <summary>
+        /// Limit strain of proportionality, dimensionless
+        /// </summary>
+        double StrainOfProportionality { get; set; }
+        /// <summary>
+        /// Strain at point of start of yelding, dimensionless
+        /// </summary>
+        double StrainOfStartOfYielding { get; set; }
+        /// <summary>
+        /// Strain at point of end of yelding, dimensionless
+        /// </summary>
+        double StrainOfEndOfYielding { get; set; }
+        /// <summary>
+        /// Strain at point of ultimate strength, dimensionless
+        /// </summary>
+        double StrainOfUltimateStrength { get; set; }
+        /// <summary>
+        /// Strain at point of fracture
+        /// </summary>
+        double StrainOfFracture { get; set; }
+        /// <summary>
+        /// Stress at point of ultimate strength, Pa for absolute value, dimensionless for relative value 
+        /// </summary>
+        double StressOfUltimateStrength { get; set; }
+        /// <summary>
+        /// Stress at point of fracture, Pa for absolute value, dimensionless for relative value 
+        /// </summary>
+        double StressOfFracture { get; set; }
+    }
+}
\ No newline at end of file
diff --git a/StructureHelperCommon/Models/Materials/Libraries/ISteelDiagramRelativeProperty.cs b/StructureHelperCommon/Models/Materials/Libraries/ISteelDiagramRelativeProperty.cs
new file mode 100644
index 0000000..249cc63
--- /dev/null
+++ b/StructureHelperCommon/Models/Materials/Libraries/ISteelDiagramRelativeProperty.cs
@@ -0,0 +1,18 @@
+using StructureHelperCommon.Infrastructures.Interfaces;
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace StructureHelperCommon.Models.Materials.Libraries
+{
+    public interface ISteelDiagramRelativeProperty
+    {
+        double StrainOfProportionality { get; set; }
+        double StrainOfStartOfYielding { get; set; }
+        double StrainOfEndOfYielding { get; set; }
+        double StrainOfUltimateStrength { get; set; }
+        double StressOfUltimateStrength { get; set; }
+        double StrainOfFracture { get; set; }
+        double StressOfFracture { get; set; }
+    }
+}
diff --git a/StructureHelperCommon/Models/Materials/Libraries/ISteelMaterialEntity.cs b/StructureHelperCommon/Models/Materials/Libraries/ISteelMaterialEntity.cs
new file mode 100644
index 0000000..bfdbfce
--- /dev/null
+++ b/StructureHelperCommon/Models/Materials/Libraries/ISteelMaterialEntity.cs
@@ -0,0 +1,11 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace StructureHelperCommon.Models.Materials.Libraries
+{
+    public interface ISteelMaterialEntity : ILibMaterialEntity
+    {
+        SteelDiagramPropertyType PropertyType { get; set; }
+    }
+}
diff --git a/StructureHelperCommon/Models/Materials/Libraries/ISteelMaterialLogicOption.cs b/StructureHelperCommon/Models/Materials/Libraries/ISteelMaterialLogicOption.cs
new file mode 100644
index 0000000..9faa80a
--- /dev/null
+++ b/StructureHelperCommon/Models/Materials/Libraries/ISteelMaterialLogicOption.cs
@@ -0,0 +1,11 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace StructureHelperCommon.Models.Materials.Libraries
+{
+    internal interface ISteelMaterialLogicOption : IMaterialLogicOptions
+    {
+        double MaxPlasticStrainRatio { get; set; }
+    }
+}
diff --git a/StructureHelperCommon/Models/Materials/Libraries/LibMaterialPepository.cs b/StructureHelperCommon/Models/Materials/Libraries/LibMaterialPepository.cs
index 73ddc2a..9f989f5 100644
--- a/StructureHelperCommon/Models/Materials/Libraries/LibMaterialPepository.cs
+++ b/StructureHelperCommon/Models/Materials/Libraries/LibMaterialPepository.cs
@@ -36,5 +36,15 @@ namespace StructureHelperCommon.Models.Materials.Libraries
                 .ToList();
             return repository;
         }
+
+        public static List<ILibMaterialEntity> GetSteelRepository()
+        {
+            var natCodes = ProgramSetting.CodesList;
+            var rep = GetRepository();
+            var repository = rep
+                .Where(x => natCodes.Contains(x.Code) & x is ISteelMaterialEntity)
+                .ToList();
+            return repository;
+        }
     }
 }
diff --git a/StructureHelperCommon/Models/Materials/Libraries/Logics/SteelMaterialBuilderLogic.cs b/StructureHelperCommon/Models/Materials/Libraries/Logics/SteelMaterialBuilderLogic.cs
new file mode 100644
index 0000000..482bcbb
--- /dev/null
+++ b/StructureHelperCommon/Models/Materials/Libraries/Logics/SteelMaterialBuilderLogic.cs
@@ -0,0 +1,116 @@
+using LoaderCalculator.Data.Materials;
+using LoaderCalculator.Data.Materials.DiagramTemplates;
+using LoaderCalculator.Data.Materials.MaterialBuilders;
+using StructureHelperCommon.Infrastructures.Enums;
+using StructureHelperCommon.Infrastructures.Exceptions;
+using StructureHelperCommon.Infrastructures.Interfaces;
+using System;
+using System.Collections.Generic;
+
+namespace StructureHelperCommon.Models.Materials.Libraries
+{
+    public class SteelMaterialBuilderLogic : IMaterialLogic
+    {
+        private const double safetyFactorForULS = 1.05;
+        private const double safetyFactorforSLS = 1.0;
+        private ISteelMaterialLogicOption option;
+        IObjectConvertStrategy<ISteelDiagramAbsoluteProperty, ISteelDiagramRelativeProperty> convertStrategy;
+        private IMaterialFactorLogic factorLogic;
+        private double compressionStrength;
+        private double tensionStrength;
+
+        public Guid Id { get; }
+        public string Name { get; set; }
+        public IMaterialLogicOptions Options { get; set; }
+        public MaterialTypes MaterialType { get; set; }
+        public DiagramType DiagramType { get; set; }
+
+
+        public SteelMaterialBuilderLogic(Guid id)
+        {
+            Id = id;
+        }
+
+        public IMaterial GetLoaderMaterial()
+        {
+            option = Options as ISteelMaterialLogicOption;
+            if (DiagramType == DiagramType.TripleLinear)
+            {
+                factorLogic = new MaterialFactorLogic(Options.SafetyFactors);
+                GetStrength();
+                Material material = new()
+                {
+                    InitModulus = option.MaterialEntity.InitialModulus,
+                    Diagram = GetDiagram(),
+                    LimitPositiveStrain = GetMaxStrain(tensionStrength),
+                    LimitNegativeStrain = -GetMaxStrain(compressionStrength),
+                };
+                return material;
+            }
+            else
+            {
+                throw new StructureHelperException(ErrorStrings.ObjectTypeIsUnknownObj(DiagramType));
+            }
+        }
+
+        private double GetMaxStrain(double strength)
+        {
+            double elasticCompressionStrain = strength / Options.MaterialEntity.InitialModulus;
+            double fullCompressionStrain = elasticCompressionStrain * (1 + ((ISteelMaterialLogicOption)Options).MaxPlasticStrainRatio);
+            return fullCompressionStrain;
+        }
+
+        private Func<double, double> GetDiagram()
+        {
+            MultiLinearStressStrainDiagram compressionDiagram = GetMultiLinearDiagram(compressionStrength);
+            MultiLinearStressStrainDiagram tensionDiagram = GetMultiLinearDiagram(tensionStrength);
+            var posNegDiagram = new PosNegDigramDecorator(tensionDiagram, compressionDiagram);
+            return posNegDiagram.GetStressByStrain;
+        }
+
+        private MultiLinearStressStrainDiagram GetMultiLinearDiagram(double strength)
+        {
+            convertStrategy = new SteelRelativeToAbsoluteDiagramConvertLogic(Options.MaterialEntity.InitialModulus, strength);
+            var diagramProperty = SteelDiagramPropertyFactory.GetProperty(((ISteelMaterialEntity)Options.MaterialEntity).PropertyType);
+            var absoluteProperty = convertStrategy.Convert(diagramProperty);
+            List<IStressStrainPair> stressStrainPairs = new()
+            {
+                new StressStrainPair() { Stress = 0, Strain = 0},
+                new StressStrainPair() { Stress = absoluteProperty.StressOfProportionality, Strain = absoluteProperty.StrainOfProportionality},
+                new StressStrainPair() { Stress = absoluteProperty.BaseStrength, Strain = absoluteProperty.StrainOfStartOfYielding},
+                new StressStrainPair() { Stress = absoluteProperty.BaseStrength, Strain = absoluteProperty.StrainOfEndOfYielding},
+                new StressStrainPair() { Stress = absoluteProperty.StressOfUltimateStrength, Strain = absoluteProperty.StrainOfUltimateStrength},
+                new StressStrainPair() { Stress = absoluteProperty.StressOfFracture, Strain = absoluteProperty.StrainOfFracture},
+
+            };
+            var multiDiagram = new MultiLinearStressStrainDiagram(stressStrainPairs);
+            return multiDiagram;
+        }
+
+        public void GetStrength()
+        {
+            double baseStength = Options.MaterialEntity.MainStrength;
+            var factors = factorLogic.GetTotalFactor(Options.LimitState, Options.CalcTerm);
+            double compressionFactor = 1d;
+            double tensionFactor = 1d;
+            compressionFactor *= factors.Compressive;
+            tensionFactor *= factors.Tensile;
+            double factor;
+            if (Options.LimitState == Infrastructures.Enums.LimitStates.ULS)
+            {
+                factor = safetyFactorForULS;
+            }
+            else if (Options.LimitState == Infrastructures.Enums.LimitStates.SLS)
+            {
+                factor = safetyFactorforSLS;
+            }
+            else
+            {
+                throw new StructureHelperException(ErrorStrings.ObjectTypeIsUnknownObj(Options.LimitState));
+            }
+            double strength = baseStength / factor;
+            compressionStrength = strength * compressionFactor;
+            tensionStrength = strength * tensionFactor;
+        }
+    }
+}
diff --git a/StructureHelperCommon/Models/Materials/Libraries/Logics/SteelRelativeToAbsoluteDiagramConvertLogic.cs b/StructureHelperCommon/Models/Materials/Libraries/Logics/SteelRelativeToAbsoluteDiagramConvertLogic.cs
new file mode 100644
index 0000000..c8cb596
--- /dev/null
+++ b/StructureHelperCommon/Models/Materials/Libraries/Logics/SteelRelativeToAbsoluteDiagramConvertLogic.cs
@@ -0,0 +1,54 @@
+using StructureHelperCommon.Infrastructures.Exceptions;
+using StructureHelperCommon.Infrastructures.Interfaces;
+
+namespace StructureHelperCommon.Models.Materials.Libraries
+{
+    public class SteelRelativeToAbsoluteDiagramConvertLogic : IObjectConvertStrategy<ISteelDiagramAbsoluteProperty, ISteelDiagramRelativeProperty>
+    {
+        private readonly double initialYoungsModulus;
+        private readonly double baseStrength;
+
+        /// <summary>
+        /// Converts relatives properties of diagram of steel to absolute one
+        /// </summary>
+        /// <param name="initialYoungsModulus">Initial modulus of elasticity (Young's modulus), Pa</param>
+        /// <param name="baseStrength">Stress of yelding, Pa</param>
+        public SteelRelativeToAbsoluteDiagramConvertLogic(double initialYoungsModulus, double baseStrength)
+        {
+            this.initialYoungsModulus = initialYoungsModulus;
+            this.baseStrength = baseStrength;
+        }
+
+        public ISteelDiagramAbsoluteProperty Convert(ISteelDiagramRelativeProperty source)
+        {
+            CheckInputData(source);
+            double absoluteYieldingStrain = baseStrength / initialYoungsModulus;
+            SteelDiagramAbsoluteProperty result = new()
+            {
+                InitialYoungsModulus = initialYoungsModulus,
+                BaseStrength = baseStrength,
+                StressOfProportionality = baseStrength * source.StrainOfProportionality,
+                StrainOfProportionality = absoluteYieldingStrain * source.StrainOfProportionality,
+                StrainOfStartOfYielding = absoluteYieldingStrain * source.StrainOfStartOfYielding,
+                StrainOfEndOfYielding = absoluteYieldingStrain * source.StrainOfEndOfYielding,
+                StrainOfUltimateStrength = absoluteYieldingStrain * source.StrainOfUltimateStrength,
+                StrainOfFracture = absoluteYieldingStrain * source.StrainOfFracture,
+                StressOfUltimateStrength = baseStrength * source.StressOfUltimateStrength,
+                StressOfFracture = baseStrength * source.StressOfFracture,
+            };
+            return result;
+        }
+
+        private void CheckInputData(ISteelDiagramRelativeProperty source)
+        {
+            if (initialYoungsModulus <= 0.0)
+            {
+                throw new StructureHelperException(ErrorStrings.DataIsInCorrect + $": Initial modulus is not correct, it must be positive, but was {initialYoungsModulus}");
+            }
+            if (baseStrength < 0.0)
+            {
+                throw new StructureHelperException(ErrorStrings.DataIsInCorrect + $": Stress of yelding is not correct, it must be positive, but was {baseStrength}");
+            }
+        }
+    }
+}
diff --git a/StructureHelperCommon/Models/Materials/Libraries/ReinforcementMaterialEntity.cs b/StructureHelperCommon/Models/Materials/Libraries/ReinforcementMaterialEntity.cs
index 0537189..0fe05a6 100644
--- a/StructureHelperCommon/Models/Materials/Libraries/ReinforcementMaterialEntity.cs
+++ b/StructureHelperCommon/Models/Materials/Libraries/ReinforcementMaterialEntity.cs
@@ -11,7 +11,7 @@ namespace StructureHelperCommon.Models.Materials.Libraries
         public ICodeEntity Code { get; set; }
         public string Name { get; set; }
         public double MainStrength { get; set; }
-        public double InitModulus { get; set; }
+        public double InitialModulus { get; set; }
 
         public ReinforcementMaterialEntity(Guid id)
         {
diff --git a/StructureHelperCommon/Models/Materials/Libraries/SteelDiagramAbsoluteProperty.cs b/StructureHelperCommon/Models/Materials/Libraries/SteelDiagramAbsoluteProperty.cs
new file mode 100644
index 0000000..c2d480e
--- /dev/null
+++ b/StructureHelperCommon/Models/Materials/Libraries/SteelDiagramAbsoluteProperty.cs
@@ -0,0 +1,31 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace StructureHelperCommon.Models.Materials.Libraries
+{
+    /// <inheritdoc/>
+    public class SteelDiagramAbsoluteProperty : ISteelDiagramAbsoluteProperty
+    {
+        /// <inheritdoc/>
+        public double InitialYoungsModulus { get; set; }
+        /// <inheritdoc/>
+        public double BaseStrength { get; set; }
+        /// <inheritdoc/>
+        public double StrainOfProportionality { get; set; }
+        /// <inheritdoc/>
+        public double StrainOfStartOfYielding { get; set; }
+        /// <inheritdoc/>
+        public double StrainOfEndOfYielding { get; set; }
+        /// <inheritdoc/>
+        public double StrainOfUltimateStrength { get; set; }
+        /// <inheritdoc/>
+        public double StrainOfFracture { get; set; }
+        /// <inheritdoc/>
+        public double StressOfProportionality { get; set; }
+        /// <inheritdoc/>
+        public double StressOfUltimateStrength { get; set; }
+        /// <inheritdoc/>
+        public double StressOfFracture { get; set; }
+    }
+}
diff --git a/StructureHelperCommon/Models/Materials/Libraries/SteelDiagramRelativeProperty.cs b/StructureHelperCommon/Models/Materials/Libraries/SteelDiagramRelativeProperty.cs
new file mode 100644
index 0000000..72592b6
--- /dev/null
+++ b/StructureHelperCommon/Models/Materials/Libraries/SteelDiagramRelativeProperty.cs
@@ -0,0 +1,17 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace StructureHelperCommon.Models.Materials.Libraries
+{
+    public class SteelDiagramRelativeProperty : ISteelDiagramRelativeProperty
+    {
+        public double StrainOfProportionality { get; set; }
+        public double StrainOfStartOfYielding { get; set; }
+        public double StrainOfEndOfYielding { get; set; }
+        public double StrainOfUltimateStrength { get; set; }
+        public double StressOfUltimateStrength { get; set; }
+        public double StrainOfFracture { get; set; }
+        public double StressOfFracture { get; set; }
+    }
+}
diff --git a/StructureHelperCommon/Models/Materials/Libraries/SteelMaterialEntity.cs b/StructureHelperCommon/Models/Materials/Libraries/SteelMaterialEntity.cs
new file mode 100644
index 0000000..d71a4fa
--- /dev/null
+++ b/StructureHelperCommon/Models/Materials/Libraries/SteelMaterialEntity.cs
@@ -0,0 +1,28 @@
+using StructureHelperCommon.Infrastructures.Enums;
+using StructureHelperCommon.Models.Codes;
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace StructureHelperCommon.Models.Materials.Libraries
+{
+    public class SteelMaterialEntity : ISteelMaterialEntity
+    {
+        public Guid Id { get; }
+        public CodeTypes CodeType { get; set; }
+        public SteelDiagramPropertyType PropertyType { get; set; }
+
+        public ICodeEntity Code { get; set; }
+
+        public string Name { get; set; } = string.Empty;
+
+        public double InitialModulus { get; set; }
+
+        public double MainStrength { get; set; }
+
+        public SteelMaterialEntity(Guid id)
+        {
+            Id = id;
+        }
+    }
+}
diff --git a/StructureHelperCommon/Models/Materials/Libraries/SteelMaterialLogicOption.cs b/StructureHelperCommon/Models/Materials/Libraries/SteelMaterialLogicOption.cs
new file mode 100644
index 0000000..3f49aa4
--- /dev/null
+++ b/StructureHelperCommon/Models/Materials/Libraries/SteelMaterialLogicOption.cs
@@ -0,0 +1,18 @@
+using StructureHelperCommon.Infrastructures.Enums;
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace StructureHelperCommon.Models.Materials.Libraries
+{
+    public class SteelMaterialLogicOption : ISteelMaterialLogicOption
+    {
+        public List<IMaterialSafetyFactor> SafetyFactors { get; set; }
+        public ILibMaterialEntity MaterialEntity { get; set; }
+        public LimitStates LimitState { get; set; }
+        public CalcTerms CalcTerm { get; set; }
+        public bool WorkInCompression { get; set; } = true;
+        public bool WorkInTension { get; set; } = true;
+        public double MaxPlasticStrainRatio { get; set; }
+    }
+}
diff --git a/StructureHelperCommon/Models/Materials/MaterialCommonOptionLogic.cs b/StructureHelperCommon/Models/Materials/MaterialCommonOptionLogic.cs
index 746cf49..617e130 100644
--- a/StructureHelperCommon/Models/Materials/MaterialCommonOptionLogic.cs
+++ b/StructureHelperCommon/Models/Materials/MaterialCommonOptionLogic.cs
@@ -19,7 +19,7 @@ namespace StructureHelperCommon.Models.Materials
 
         public void SetMaterialOptions(LCMB.IMaterialOptions materialOptions)
         {
-            materialOptions.InitModulus = options.MaterialEntity.InitModulus;
+            materialOptions.InitModulus = options.MaterialEntity.InitialModulus;
             materialOptions.Strength = options.MaterialEntity.MainStrength;
             ProcessCodeType(materialOptions);
             ProcessLimitState(materialOptions);
diff --git a/StructureHelperCommon/Models/Materials/MaterialLogicOption.cs b/StructureHelperCommon/Models/Materials/MaterialLogicOption.cs
new file mode 100644
index 0000000..38c19ba
--- /dev/null
+++ b/StructureHelperCommon/Models/Materials/MaterialLogicOption.cs
@@ -0,0 +1,18 @@
+using StructureHelperCommon.Infrastructures.Enums;
+using StructureHelperCommon.Models.Materials.Libraries;
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace StructureHelperCommon.Models.Materials
+{
+    public class MaterialLogicOption : IMaterialLogicOptions
+    {
+        public List<IMaterialSafetyFactor> SafetyFactors { get; set; }
+        public ILibMaterialEntity MaterialEntity { get; set; }
+        public LimitStates LimitState { get; set; }
+        public CalcTerms CalcTerm { get; set; }
+        public bool WorkInCompression { get; set; } = true;
+        public bool WorkInTension { get; set; } = true;
+    }
+}
diff --git a/StructureHelperCommon/Models/Materials/ReinforcementByBuilderLogic.cs b/StructureHelperCommon/Models/Materials/ReinforcementByBuilderLogic.cs
index 70dd8fb..0f0cc45 100644
--- a/StructureHelperCommon/Models/Materials/ReinforcementByBuilderLogic.cs
+++ b/StructureHelperCommon/Models/Materials/ReinforcementByBuilderLogic.cs
@@ -1,7 +1,6 @@
 using LoaderCalculator.Data.Materials;
 using LoaderCalculator.Data.Materials.MaterialBuilders;
 using StructureHelperCommon.Infrastructures.Enums;
-using StructureHelperCommon.Infrastructures.Exceptions;
 using StructureHelperCommon.Services;
 using System;
 
diff --git a/StructureHelperLogics/Models/Materials/Factories/HeadMaterialFactory.cs b/StructureHelperLogics/Models/Materials/Factories/HeadMaterialFactory.cs
index 727da6e..2ea3e00 100644
--- a/StructureHelperLogics/Models/Materials/Factories/HeadMaterialFactory.cs
+++ b/StructureHelperLogics/Models/Materials/Factories/HeadMaterialFactory.cs
@@ -7,12 +7,14 @@ namespace StructureHelperLogics.Models.Materials
 {
     public enum HeadmaterialType
     {
-        Concrete40,
-        Reinforcement400,
-        Reinforcement500,
-        Elastic200,
-        Carbon1400,
-        Glass1200
+        Concrete40 = 0,
+        Reinforcement400 = 1,
+        Reinforcement500 = 2,
+        Elastic200 = 3,
+        Carbon1400 = 4,
+        Glass1200 = 5,
+        SteelS245 = 6,
+        SteelS345 = 7,
     }     
 
     public static class HeadMaterialFactory
@@ -20,23 +22,46 @@ namespace StructureHelperLogics.Models.Materials
         private static CodeTypes codeType;
         private static IEnumerable<ILibMaterialEntity> LibConcreteMaterials => LibMaterialPepository.GetConcreteRepository();
         private static IEnumerable<ILibMaterialEntity> LibReinforcementMaterials => LibMaterialPepository.GetReinforcementRepository();
+        private static IEnumerable<ILibMaterialEntity> LibSteelMaterials => LibMaterialPepository.GetSteelRepository();
 
         public static IHeadMaterial GetHeadMaterial(HeadmaterialType type)
         {
             if (type == HeadmaterialType.Concrete40) { return GetConcrete40(); }
-            if (type == HeadmaterialType.Reinforcement400) { return GetReinforcement400(); }
-            if (type == HeadmaterialType.Reinforcement500) { return GetReinforcement500(); }
-            if (type == HeadmaterialType.Elastic200) { return GetElastic200(); }
-            if (type == HeadmaterialType.Carbon1400) { return GetCarbon1400(); }
-            if (type == HeadmaterialType.Glass1200) { return GetGlass1200(); }
+            else if (type == HeadmaterialType.Reinforcement400) { return GetReinforcement400(); }
+            else if (type == HeadmaterialType.Reinforcement500) { return GetReinforcement500(); }
+            else if (type == HeadmaterialType.Elastic200) { return GetElastic200(); }
+            else if (type == HeadmaterialType.Carbon1400) { return GetCarbon1400(); }
+            else if (type == HeadmaterialType.Glass1200) { return GetGlass1200(); }
+            else if (type == HeadmaterialType.SteelS245) { return GetSteelS245(); }
+            else if (type == HeadmaterialType.SteelS345) { return GetSteelS345(); }
             else throw new StructureHelperException(ErrorStrings.ObjectTypeIsUnknown + nameof(type));
         }
 
+        private static IHeadMaterial GetSteelS245()
+        {
+            var material = new HeadMaterial() { Name = "New steel" };
+            var libMaterial = LibSteelMaterials.Where(x => x.Name.Contains("245")).First();
+            var libMat = new SteelLibMaterial(Guid.NewGuid());
+            libMat.MaterialEntity = libMaterial;
+            material.HelperMaterial = libMat;
+            return material;
+        }
+
+        private static IHeadMaterial GetSteelS345()
+        {
+            var material = new HeadMaterial() { Name = "New steel" };
+            var libMaterial = LibSteelMaterials.Where(x => x.Name.Contains("345")).First();
+            var libMat = new SteelLibMaterial(Guid.NewGuid());
+            libMat.MaterialEntity = libMaterial;
+            material.HelperMaterial = libMat;
+            return material;
+        }
+
         private static IHeadMaterial GetReinforcement500()
         {
             var material = new HeadMaterial() { Name = "New reinforcement" };
             var libMaterial = LibReinforcementMaterials.Where(x => x.Name.Contains("500")).First();
-            var libMat = new ReinforcementLibMaterial();
+            var libMat = new ReinforcementLibMaterial(Guid.NewGuid());
             libMat.MaterialEntity = libMaterial;
             material.HelperMaterial = libMat;
             return material;
@@ -77,7 +102,7 @@ namespace StructureHelperLogics.Models.Materials
         {
             var material = new HeadMaterial() { Name = "New reinforcement" };
             var libMaterial = LibReinforcementMaterials.Where(x => x.Name.Contains("400")).First();
-            var libMat = new ReinforcementLibMaterial();
+            var libMat = new ReinforcementLibMaterial(Guid.NewGuid());
             libMat.MaterialEntity = libMaterial;
             material.HelperMaterial = libMat;
             return material;
diff --git a/StructureHelperLogics/Models/Materials/ISteelLibMaterial.cs b/StructureHelperLogics/Models/Materials/ISteelLibMaterial.cs
new file mode 100644
index 0000000..53ceb79
--- /dev/null
+++ b/StructureHelperLogics/Models/Materials/ISteelLibMaterial.cs
@@ -0,0 +1,12 @@
+using StructureHelperCommon.Models.Materials;
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace StructureHelperLogics.Models.Materials
+{
+    public interface ISteelLibMaterial : ILibMaterial
+    {
+        double MaxPlasticStrainRatio { get; set; }
+    }
+}
diff --git a/StructureHelperLogics/Models/Materials/Logics/ConcreteLibUpdateStrategy.cs b/StructureHelperLogics/Models/Materials/Logics/ConcreteLibUpdateStrategy.cs
index f22b458..1b296de 100644
--- a/StructureHelperLogics/Models/Materials/Logics/ConcreteLibUpdateStrategy.cs
+++ b/StructureHelperLogics/Models/Materials/Logics/ConcreteLibUpdateStrategy.cs
@@ -7,11 +7,12 @@ namespace StructureHelperLogics.Models.Materials
     public class ConcreteLibUpdateStrategy : IUpdateStrategy<IConcreteLibMaterial>
     {
         private IUpdateStrategy<ILibMaterial> libUpdateStrategy;
+        private IUpdateStrategy<ILibMaterial> LibUpdateStrategy => libUpdateStrategy ??= new LibMaterialUpdateStrategy();
         public ConcreteLibUpdateStrategy(IUpdateStrategy<ILibMaterial> libUpdateStrategy)
         {
             this.libUpdateStrategy = libUpdateStrategy;
         }
-        public ConcreteLibUpdateStrategy() : this(new LibMaterialUpdateStrategy())
+        public ConcreteLibUpdateStrategy()
         {
             
         }
@@ -20,7 +21,7 @@ namespace StructureHelperLogics.Models.Materials
             CheckObject.ThrowIfNull(sourceObject);
             CheckObject.ThrowIfNull(targetObject);
             if (ReferenceEquals(targetObject, sourceObject)) { return; }
-            libUpdateStrategy.Update(targetObject, sourceObject);
+            LibUpdateStrategy.Update(targetObject, sourceObject);
             targetObject.TensionForULS = sourceObject.TensionForULS;
             targetObject.TensionForSLS = sourceObject.TensionForSLS;
             targetObject.RelativeHumidity = sourceObject.RelativeHumidity;
diff --git a/StructureHelperLogics/Models/Materials/Logics/GetSteelLoaderMaterialLogic.cs b/StructureHelperLogics/Models/Materials/Logics/GetSteelLoaderMaterialLogic.cs
new file mode 100644
index 0000000..d9c46e0
--- /dev/null
+++ b/StructureHelperLogics/Models/Materials/Logics/GetSteelLoaderMaterialLogic.cs
@@ -0,0 +1,63 @@
+using LoaderCalculator.Data.Materials;
+using LoaderCalculator.Data.Materials.DiagramTemplates;
+using StructureHelperCommon.Infrastructures.Interfaces;
+using StructureHelperCommon.Models.Materials.Libraries;
+using System;
+using System.Collections.Generic;
+using System.Security.Policy;
+using System.Text;
+using System.Windows.Media.TextFormatting;
+
+namespace StructureHelperLogics.Models.Materials.Logics
+{
+    public class GetSteelLoaderMaterialLogic
+    {
+        IObjectConvertStrategy<ISteelDiagramAbsoluteProperty, ISteelDiagramRelativeProperty> convertStrategy;
+
+        public double InitialModulus { get; set; }
+        public double CompressionStrength { get; set; }
+        public double TensionStrength { get; internal set; }
+        public double MaxPlasticStrainRatio { get; set; }
+        public ISteelDiagramRelativeProperty DiagramProperty { get; set; }
+
+        public IMaterial GetMaterial()
+        {
+            double elasticCompressionStrain = CompressionStrength / InitialModulus;
+            double fullCompressionStrain = elasticCompressionStrain * (1 + MaxPlasticStrainRatio);
+
+            Material material = new()
+            {
+                Diagram = GetDiagram(),
+                LimitPositiveStrain = fullCompressionStrain,
+                LimitNegativeStrain = - fullCompressionStrain,
+            };
+            return material;
+        }
+
+        private Func<double, double> GetDiagram()
+        {
+            MultiLinearStressStrainDiagram compressionDiagram = GetMultiLinearDiagram(CompressionStrength);
+            MultiLinearStressStrainDiagram tensionDiagram = GetMultiLinearDiagram(TensionStrength);
+            var posNegDiagram = new PosNegDigramDecorator(tensionDiagram, compressionDiagram);
+            return posNegDiagram.GetStressByStrain;
+        }
+
+        private MultiLinearStressStrainDiagram GetMultiLinearDiagram(double strength)
+        {
+            convertStrategy ??= new SteelRelativeToAbsoluteDiagramConvertLogic(InitialModulus, strength);
+            var absoluteProperty = convertStrategy.Convert(DiagramProperty);
+            List<IStressStrainPair> stressStrainPairs = new()
+            {
+                new StressStrainPair() { Stress = 0, Strain = 0},
+                new StressStrainPair() { Stress = absoluteProperty.StressOfProportionality, Strain = absoluteProperty.StrainOfProportionality},
+                new StressStrainPair() { Stress = absoluteProperty.BaseStrength, Strain = absoluteProperty.StrainOfStartOfYielding},
+                new StressStrainPair() { Stress = absoluteProperty.BaseStrength, Strain = absoluteProperty.StrainOfEndOfYielding},
+                new StressStrainPair() { Stress = absoluteProperty.StressOfUltimateStrength, Strain = absoluteProperty.StrainOfUltimateStrength},
+                new StressStrainPair() { Stress = absoluteProperty.StressOfFracture, Strain = absoluteProperty.StrainOfFracture},
+
+            };
+            var multiDiagram = new MultiLinearStressStrainDiagram(stressStrainPairs);
+            return multiDiagram;
+        }
+    }
+}
diff --git a/StructureHelperLogics/Models/Materials/Logics/HelperMaterialUpdateStrategy.cs b/StructureHelperLogics/Models/Materials/Logics/HelperMaterialUpdateStrategy.cs
index 695671f..651e149 100644
--- a/StructureHelperLogics/Models/Materials/Logics/HelperMaterialUpdateStrategy.cs
+++ b/StructureHelperLogics/Models/Materials/Logics/HelperMaterialUpdateStrategy.cs
@@ -14,10 +14,16 @@ namespace StructureHelperLogics.Models.Materials
 {
     public class HelperMaterialUpdateStrategy : IUpdateStrategy<IHelperMaterial>
     {
-        private IUpdateStrategy<IElasticMaterial> elasticStrategy;
-        private IUpdateStrategy<IFRMaterial> frStrategy;
-        private IUpdateStrategy<IConcreteLibMaterial> concreteStrategy;
-        private IUpdateStrategy<IReinforcementLibMaterial> reinforcementStrategy;
+        private IUpdateStrategy<IElasticMaterial> elasticUpdateStrategy;
+        private IUpdateStrategy<IFRMaterial> frUpdateStrategy;
+        private IUpdateStrategy<IConcreteLibMaterial> concreteUpdateStrategy;
+        private IUpdateStrategy<IReinforcementLibMaterial> reinforcementUpdateStrategy;
+        private IUpdateStrategy<ISteelLibMaterial> steelUpdateStrategy;
+        private IUpdateStrategy<IElasticMaterial> ElasticUpdateStrategy => elasticUpdateStrategy ??= new ElasticUpdateStrategy();
+        private IUpdateStrategy<IFRMaterial> FrUpdateStrategy => frUpdateStrategy ??= new FRUpdateStrategy();
+        private IUpdateStrategy<IConcreteLibMaterial> ConcreteUpdateStrategy => concreteUpdateStrategy ??= new ConcreteLibUpdateStrategy();
+        private IUpdateStrategy<IReinforcementLibMaterial> ReinforcementUpdateStrategy => reinforcementUpdateStrategy ??= new ReinforcementLibUpdateStrategy();
+        private IUpdateStrategy<ISteelLibMaterial> SteelUpdateStrategy => steelUpdateStrategy ??= new SteelLibMaterialUpdateStrategy();
         private IUpdateStrategy<IHelperMaterial> safetyFactorUpdateStrategy = new HelpermaterialSafetyFactorsUpdateStrategy();
         public HelperMaterialUpdateStrategy(IUpdateStrategy<IElasticMaterial> elasticStrategy,
             IUpdateStrategy<IFRMaterial> frStrategy,
@@ -25,17 +31,12 @@ namespace StructureHelperLogics.Models.Materials
             IUpdateStrategy<IReinforcementLibMaterial> reinforcementStrategy
             )
         {
-            this.elasticStrategy = elasticStrategy;
-            this.frStrategy = frStrategy;
-            this.concreteStrategy = concreteStrategy;
-            this.reinforcementStrategy = reinforcementStrategy;
+            this.elasticUpdateStrategy = elasticStrategy;
+            this.frUpdateStrategy = frStrategy;
+            this.concreteUpdateStrategy = concreteStrategy;
+            this.reinforcementUpdateStrategy = reinforcementStrategy;
         }
-        public HelperMaterialUpdateStrategy() : this(
-            new ElasticUpdateStrategy(),
-            new FRUpdateStrategy(),
-            new ConcreteLibUpdateStrategy(),
-            new ReinforcementLibUpdateStrategy()
-        )
+        public HelperMaterialUpdateStrategy()
         { }
 
         public void Update(IHelperMaterial targetObject, IHelperMaterial sourceObject)
@@ -50,11 +51,11 @@ namespace StructureHelperLogics.Models.Materials
             }
             else if (sourceObject is IElasticMaterial)
             {
-                elasticStrategy.Update(targetObject as IElasticMaterial, sourceObject as IElasticMaterial);
+                ElasticUpdateStrategy.Update(targetObject as IElasticMaterial, sourceObject as IElasticMaterial);
             }
             else if (sourceObject is IFRMaterial)
             {
-                frStrategy.Update(targetObject as IFRMaterial, sourceObject as IFRMaterial);
+                FrUpdateStrategy.Update(targetObject as IFRMaterial, sourceObject as IFRMaterial);
             }
             else
             {
@@ -66,11 +67,15 @@ namespace StructureHelperLogics.Models.Materials
         {
             if (sourceObject is IConcreteLibMaterial concreteLibMaterial)
             {
-                concreteStrategy.Update(targetObject as IConcreteLibMaterial, concreteLibMaterial);
+                concreteUpdateStrategy.Update(targetObject as IConcreteLibMaterial, concreteLibMaterial);
             }
             else if (sourceObject is IReinforcementLibMaterial reinforcementLibMaterial)
             {
-                reinforcementStrategy.Update(targetObject as IReinforcementLibMaterial, reinforcementLibMaterial);
+                ReinforcementUpdateStrategy.Update(targetObject as IReinforcementLibMaterial, reinforcementLibMaterial);
+            }
+            else if (sourceObject is ISteelLibMaterial steelLibMaterial)
+            {
+                SteelUpdateStrategy.Update(targetObject as ISteelLibMaterial, steelLibMaterial);
             }
             else
             {
diff --git a/StructureHelperLogics/Models/Materials/Logics/SteelLibMaterialUpdateStrategy.cs b/StructureHelperLogics/Models/Materials/Logics/SteelLibMaterialUpdateStrategy.cs
new file mode 100644
index 0000000..745e6c2
--- /dev/null
+++ b/StructureHelperLogics/Models/Materials/Logics/SteelLibMaterialUpdateStrategy.cs
@@ -0,0 +1,34 @@
+using StructureHelperCommon.Infrastructures.Interfaces;
+using StructureHelperCommon.Models.Materials;
+using StructureHelperCommon.Services;
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace StructureHelperLogics.Models.Materials
+{
+    public class SteelLibMaterialUpdateStrategy : IUpdateStrategy<ISteelLibMaterial>
+    {
+        private IUpdateStrategy<ILibMaterial> libUpdateStrategy;
+        private IUpdateStrategy<ILibMaterial> LibUpdateStrategy => libUpdateStrategy ??= new LibMaterialUpdateStrategy();
+
+        public SteelLibMaterialUpdateStrategy(IUpdateStrategy<ILibMaterial> libUpdateStrategy)
+        {
+            this.libUpdateStrategy = libUpdateStrategy;
+        }
+
+        public SteelLibMaterialUpdateStrategy()
+        {
+            
+        }
+
+        public void Update(ISteelLibMaterial targetObject, ISteelLibMaterial sourceObject)
+        {
+            CheckObject.ThrowIfNull(sourceObject);
+            CheckObject.ThrowIfNull(targetObject);
+            if (ReferenceEquals(targetObject, sourceObject)) { return; }
+            LibUpdateStrategy.Update(targetObject, sourceObject);
+            targetObject.MaxPlasticStrainRatio = sourceObject.MaxPlasticStrainRatio;
+        }
+    }
+}
diff --git a/StructureHelperLogics/Models/Materials/ReinforcementLibMaterial.cs b/StructureHelperLogics/Models/Materials/ReinforcementLibMaterial.cs
index 86eb391..bd434a2 100644
--- a/StructureHelperLogics/Models/Materials/ReinforcementLibMaterial.cs
+++ b/StructureHelperLogics/Models/Materials/ReinforcementLibMaterial.cs
@@ -1,16 +1,9 @@
-using StructureHelperCommon.Infrastructures.Enums;
-using StructureHelperCommon.Models.Materials.Libraries;
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
-using Loadermaterials = LoaderCalculator.Data.Materials;
-using LMBuilders = LoaderCalculator.Data.Materials.MaterialBuilders;
-using LoaderMaterialLogics = LoaderCalculator.Data.Materials.MaterialBuilders.MaterialLogics;
-using LoaderCalculator.Data.Materials;
-using StructureHelperCommon.Models.Materials;
+using LoaderCalculator.Data.Materials;
+using StructureHelperCommon.Infrastructures.Enums;
 using StructureHelperCommon.Infrastructures.Settings;
+using StructureHelperCommon.Models.Materials;
+using StructureHelperCommon.Models.Materials.Libraries;
+using LoaderMaterialLogics = LoaderCalculator.Data.Materials.MaterialBuilders.MaterialLogics;
 
 namespace StructureHelperLogics.Models.Materials
 {
@@ -24,7 +17,7 @@ namespace StructureHelperLogics.Models.Materials
 
         public Guid Id { get; }
         public ILibMaterialEntity MaterialEntity { get; set; }
-        public List<IMaterialSafetyFactor> SafetyFactors { get; set; } = new();
+        public List<IMaterialSafetyFactor> SafetyFactors { get; set; } = [];
         public IMaterialLogic MaterialLogic { get; set; }
         public List<IMaterialLogic> MaterialLogics => materialLogics;
 
@@ -36,14 +29,9 @@ namespace StructureHelperLogics.Models.Materials
             MaterialLogic = materialLogics.First();
         }
 
-        public ReinforcementLibMaterial() : this (Guid.NewGuid())
-        {
-            
-        }
-
         public object Clone()
         {
-            var newItem = new ReinforcementLibMaterial();
+            var newItem = new ReinforcementLibMaterial(Guid.NewGuid());
             var updateStrategy = new ReinforcementLibUpdateStrategy();
             updateStrategy.Update(newItem, this);
             return newItem;
diff --git a/StructureHelperLogics/Models/Materials/SteelLibMaterial.cs b/StructureHelperLogics/Models/Materials/SteelLibMaterial.cs
new file mode 100644
index 0000000..edde285
--- /dev/null
+++ b/StructureHelperLogics/Models/Materials/SteelLibMaterial.cs
@@ -0,0 +1,89 @@
+using LoaderCalculator.Data.Materials;
+using StructureHelperCommon.Infrastructures.Enums;
+using StructureHelperCommon.Infrastructures.Exceptions;
+using StructureHelperCommon.Infrastructures.Settings;
+using StructureHelperCommon.Models.Materials;
+using StructureHelperCommon.Models.Materials.Libraries;
+using StructureHelperLogics.Models.Materials.Logics;
+
+namespace StructureHelperLogics.Models.Materials
+{
+    public class SteelLibMaterial : ISteelLibMaterial
+    {
+        const MaterialTypes materialType = MaterialTypes.Steel;
+        private const double safetyFactorForULS = 1.05;
+        private const double safetyFactorforSLS = 1.0;
+
+        private IMaterialFactorLogic factorLogic => new MaterialFactorLogic(SafetyFactors);
+        private readonly List<IMaterialLogic> materialLogics = ProgramSetting.MaterialLogics.Where(x => x.MaterialType == materialType).ToList();
+
+        public Guid Id { get; }
+        public ILibMaterialEntity MaterialEntity { get; set; }
+        public IMaterialLogic MaterialLogic { get; set; }
+
+        public List<IMaterialLogic> MaterialLogics => materialLogics;
+
+        public List<IMaterialSafetyFactor> SafetyFactors { get; set; } = [];
+        public double MaxPlasticStrainRatio { get; set; } = 3.0;
+
+        public SteelLibMaterial(Guid id)
+        {
+            Id = id;
+            MaterialLogic = materialLogics.First();
+        }
+
+
+        public object Clone()
+        {
+            SteelLibMaterial newItem = new(Guid.NewGuid());
+            var logic = new SteelLibMaterialUpdateStrategy();
+            logic.Update(newItem, this);
+            return newItem;
+        }
+
+        public IMaterial GetCrackedLoaderMaterial(LimitStates limitState, CalcTerms calcTerm)
+        {
+            return GetLoaderMaterial(limitState, calcTerm);
+        }
+
+        public IMaterial GetLoaderMaterial(LimitStates limitState, CalcTerms calcTerm)
+        {
+            SteelMaterialLogicOption options = new()
+            {
+                MaterialEntity = MaterialEntity,
+                SafetyFactors = SafetyFactors,
+                MaxPlasticStrainRatio = MaxPlasticStrainRatio,
+                LimitState = limitState,
+                CalcTerm = calcTerm,
+            };
+            MaterialLogic.Options = options;
+            var material = MaterialLogic.GetLoaderMaterial();
+            return material;
+        }
+
+        public (double Compressive, double Tensile) GetStrength(LimitStates limitState, CalcTerms calcTerm)
+        {
+            double baseStength = MaterialEntity.MainStrength;
+            var factors = factorLogic.GetTotalFactor(limitState, calcTerm);
+            double compressionFactor = 1d;
+            double tensionFactor = 1d;
+            compressionFactor *= factors.Compressive;
+            tensionFactor *= factors.Tensile;
+            double factor;
+            if (limitState == LimitStates.ULS)
+            {
+                factor = safetyFactorForULS;
+            }
+            else if (limitState == LimitStates.SLS)
+            {
+                factor = safetyFactorforSLS;
+            }
+            else
+            {
+                throw new StructureHelperException(ErrorStrings.ObjectTypeIsUnknownObj(limitState));
+            }
+            double strength = baseStength / factor;
+            return (strength * compressionFactor, strength * tensionFactor);
+        }
+    }
+}
diff --git a/StructureHelperTests/UnitTests/MaterialTests/SteelRelativeToAbsoluteDiagramConvertLogicTests.cs b/StructureHelperTests/UnitTests/MaterialTests/SteelRelativeToAbsoluteDiagramConvertLogicTests.cs
new file mode 100644
index 0000000..167cf6b
--- /dev/null
+++ b/StructureHelperTests/UnitTests/MaterialTests/SteelRelativeToAbsoluteDiagramConvertLogicTests.cs
@@ -0,0 +1,124 @@
+using NUnit.Framework;
+using NUnit.Framework.Legacy;
+using StructureHelperCommon.Infrastructures.Exceptions;
+using StructureHelperCommon.Models.Materials.Libraries;
+
+namespace StructureHelperTests.UnitTests.MaterialTests
+{
+
+
+    [TestFixture]
+    public class SteelRelativeToAbsoluteDiagramConvertLogicTests
+    {
+        private const double YoungsModulus = 200e9;   // 200 GPa
+        private const double BaseStrength = 400e6;    // 400 MPa
+
+        private SteelRelativeToAbsoluteDiagramConvertLogic logic;
+
+        [SetUp]
+        public void SetUp()
+        {
+            logic = new SteelRelativeToAbsoluteDiagramConvertLogic(
+                initialYoungsModulus: YoungsModulus,
+                baseStrength: BaseStrength);
+        }
+
+        [Test]
+        public void Convert_ValidRelativeDiagram_ReturnsCorrectAbsoluteDiagram()
+        {
+            // Arrange
+            var source = new SteelDiagramRelativeProperty
+            {
+                StrainOfProportionality = 0.5,
+                StrainOfStartOfYielding = 1.0,
+                StrainOfEndOfYielding = 1.2,
+                StrainOfUltimateStrength = 2.0,
+                StrainOfFracture = 3.0,
+                StressOfUltimateStrength = 1.1,
+                StressOfFracture = 0.8
+            };
+
+            double expectedYieldingStrain = BaseStrength / YoungsModulus;
+
+            // Act
+            var result = logic.Convert(source);
+
+            // Assert
+            Assert.That(result.InitialYoungsModulus, Is.EqualTo(YoungsModulus));
+            Assert.That(result.BaseStrength, Is.EqualTo(BaseStrength));
+
+            Assert.That(result.StressOfProportionality,
+                Is.EqualTo(BaseStrength * source.StrainOfProportionality));
+
+            Assert.That(result.StrainOfProportionality,
+                Is.EqualTo(expectedYieldingStrain * source.StrainOfProportionality));
+
+            Assert.That(result.StrainOfStartOfYielding,
+                Is.EqualTo(expectedYieldingStrain * source.StrainOfStartOfYielding));
+
+            Assert.That(result.StrainOfEndOfYielding,
+                Is.EqualTo(expectedYieldingStrain * source.StrainOfEndOfYielding));
+
+            Assert.That(result.StrainOfUltimateStrength,
+                Is.EqualTo(expectedYieldingStrain * source.StrainOfUltimateStrength));
+
+            Assert.That(result.StrainOfFracture,
+                Is.EqualTo(expectedYieldingStrain * source.StrainOfFracture));
+
+            Assert.That(result.StressOfUltimateStrength,
+                Is.EqualTo(BaseStrength * source.StressOfUltimateStrength));
+
+            Assert.That(result.StressOfFracture,
+                Is.EqualTo(BaseStrength * source.StressOfFracture));
+        }
+
+        [Test]
+        public void Convert_InitialYoungsModulusIsZero_ThrowsException()
+        {
+            // Arrange
+            var invalidLogic = new SteelRelativeToAbsoluteDiagramConvertLogic(
+                initialYoungsModulus: 0.0,
+                baseStrength: BaseStrength);
+
+            var source = CreateValidSource();
+
+            // Act + Assert
+            var ex = Assert.Throws<StructureHelperException>(
+                () => invalidLogic.Convert(source));
+
+            StringAssert.Contains("Initial modulus", ex.Message);
+        }
+
+        [Test]
+        public void Convert_BaseStrengthIsNegative_ThrowsException()
+        {
+            // Arrange
+            var invalidLogic = new SteelRelativeToAbsoluteDiagramConvertLogic(
+                initialYoungsModulus: YoungsModulus,
+                baseStrength: -1.0);
+
+            var source = CreateValidSource();
+
+            // Act + Assert
+            var ex = Assert.Throws<StructureHelperException>(
+                () => invalidLogic.Convert(source));
+
+            StringAssert.Contains("Stress of yelding", ex.Message);
+        }
+
+        private static SteelDiagramRelativeProperty CreateValidSource()
+        {
+            return new SteelDiagramRelativeProperty
+            {
+                StrainOfProportionality = 0.5,
+                StrainOfStartOfYielding = 1.0,
+                StrainOfEndOfYielding = 1.2,
+                StrainOfUltimateStrength = 2.0,
+                StrainOfFracture = 3.0,
+                StressOfUltimateStrength = 1.1,
+                StressOfFracture = 0.8
+            };
+        }
+    }
+
+}