ASTM A656/A656M Type 7 Grade 50 Introduce
ASTM A656/A656M Type 7 Grade 50 is an American Society for Testing and Materials (ASTM) steel standard that defines the properties of hot-rolled structural steel, high-strength low-alloy plates, and quenched and tempered alloy plates used in the construction of bridges and buildings. The standard is composed of three major parts, product specifications, chemical composition, and mechanical properties. ASTM A656/A656M Type 7 Grade 50 steel is used to make high-strength steel plates and components for building structures, mining equipment, industrial tools and storage tanks. Tests are conducted to verify the mechanical properties, such as the yield strength, tensile strength, and elongation of ASTM A656/A656M Type 7 Grade 50 steel.
Smelting temperature:1615°C - 1652°C
Application:High-strength low-alloy hot-rolled structural steel plate with improved forgeability
ASTM A656/A656M Type 7 Grade 50 Material Chemical Composition
The chemical composition of the ASTM A656/A656M Type 7 Grade 50 steel are as follows:
| Element | Min | Max |
|---|---|---|
| Carbon (C) | - | 0.1800 |
| Manganese (Mn) | - | 1.6500 |
| PhOsphorus (P) | - | 0.0250 |
| Sulfur (S) | - | 0.0300 |
| Silicon (Si) | - | 0.6000 |
| Vanadium (V) | - | 0.1500 |
| Nitrogen (N) | - | 0.0300 |
| Niobium (Nb) | - | 0.1000 |
| Sulfur (S) | - | 0.0350 |
| Niobium (Nb) | - | 0.1000 |
ASTM A656/A656M Type 7 Grade 50 Material Mechanical Properties
Yield strength is an indication of a material's ability to resist deformation when subject to an applied stress. Yield strength, measured in ksi, is one of the most important properties of ASTM A656/A656M Type 7 Grade 50 steel. It is the stress at which a piece of the material will no longer continue to elongate in length but will instead deform irreversibly. The minimum specified yield strength for ASTM A656/A656M Type 7 Grade 50 steel is 50 ksi.
The mechanical properties of the ASTM A656/A656M Type 7 Grade 50 steel are as follows:
| YieldRp0.2 | ≤ 949 (MPa) |
| TeileRm | ≤ 533 (MPa) |
| ImpactKV/Ku | 31(J) |
| ElongationA | 21% |
| Reduction in cross section on fractureZ | 33% |
| As-Heat-Treated Condition | Solution and Aging, Annealing, Ausaging, Q+T,etc |
| Brinell hardness (HBW) | 244 |
ASTM A656/A656M Type 7 Grade 50 Material Thermal Properties
The thermal performance parameters of the ASTM A656/A656M Type 7 Grade 50 steel are as follows:
| Temperature (°C) | 13 | 817 | 574 |
| Modulus of elasticity (GPa) | - | 126 | - |
| Mean coefficient of thermal expaion ×10-6/(°C) | - | - | 41 |
| Thermal conductivity (W/m·°C) | - | 24.3 | 41.2 |
| Specific thermal capacity (J/kg·°C) | - | 224 | - |
| Specific electrical resistivity (Ω mm²/m) | 0.44 | - | - |
| Deity (kg/dm³) | - | - | 334 |
| Poisson’s coefficient, ν | - | - | 212 |
ASTM A656/A656M Type 7 Grade 50 Material Machining Technology
The machinability of ASTM A656/A656M Type 7 Grade 50 steel can also be improved by using appropriate cutting fluid and minimizing chips. Proper pre- and post-machining heat treatment can also improve machinability.