ASTM A656/A656M A656 Type 7 Grade 690 Introduce
The low alloy content and fine grain structure of ASTM A656/A656M A656 Type 7 Grade 690 steel make it highly weldable. It has good corrosion resistance in mild and atmospheric environments with a good resistance to pitting and crevice corrosion.
Smelting temperature:1863°C - 1395°C
Application:High-strength low-alloy hot-rolled structural steel plate with improved forgeability
ASTM A656/A656M A656 Type 7 Grade 690 Material Chemical Composition
The chemical composition of the ASTM A656/A656M A656 Type 7 Grade 690 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 A656 Type 7 Grade 690 Material Mechanical Properties
Elongation is a measure of a material's ductility; it is a measure of the degree to which a material can be stretched before it fractures or breaks. Elongation is typically measured in a percent format, with higher values denoting more ductile materials that can withstand greater elongation. The minimum elongation for ASTM A656/A656M A656 Type 7 Grade 690 steel is 18%. This value is significantly greater than most other hot-rolled steel grades and indicates that ASTM A656/A656M A656 Type 7 Grade 690 is an excellent choice for components that require stretching without risk of failure.
The mechanical properties of the ASTM A656/A656M A656 Type 7 Grade 690 steel are as follows:
| YieldRp0.2 | ≤ 834 (MPa) |
| TeileRm | ≤ 822 (MPa) |
| ImpactKV/Ku | 24(J) |
| ElongationA | 12% |
| Reduction in cross section on fractureZ | 31% |
| As-Heat-Treated Condition | Solution and Aging, Annealing, Ausaging, Q+T,etc |
| Brinell hardness (HBW) | 144 |
ASTM A656/A656M A656 Type 7 Grade 690 Material Thermal Properties
The thermal performance parameters of the ASTM A656/A656M A656 Type 7 Grade 690 steel are as follows:
| Temperature (°C) | 14 | 631 | 978 |
| Modulus of elasticity (GPa) | - | 851 | - |
| Mean coefficient of thermal expaion ×10-6/(°C) | - | - | 31 |
| Thermal conductivity (W/m·°C) | - | 42.3 | 41.2 |
| Specific thermal capacity (J/kg·°C) | - | 312 | - |
| Specific electrical resistivity (Ω mm²/m) | 0.22 | - | - |
| Deity (kg/dm³) | - | - | 324 |
| Poisson’s coefficient, ν | - | - | 123 |
ASTM A656/A656M A656 Type 7 Grade 690 Material Machining Technology
The machinability of ASTM A656/A656M A656 Type 7 Grade 690 steel can also be improved by using appropriate cutting fluid and minimizing chips. Proper pre- and post-machining heat treatment can also improve machinability.