ASTM A322 Grade 8640 Introduce
ASTM A322 is a steel standard that provides specification for hot-rolled carbon, alloy and bearing steel products. This specification is used in many different applications and is mostly used to create a strong base material that is used in many construction, automobile, machining and manufacturing projects. ASTM A322 Grade 8640 is classified as a Martensitic stainless steel and contains elements such as chromium, nitrogen, manganese, and nickel. It is an iron alloy that is known for its strength, durability, and heat resistance. This particular steel is a type that can be used in various different types of applications.
Smelting temperature:1442°C - 1261°C
Application:Alloy steel bar. Level
ASTM A322 Grade 8640 Material Chemical Composition
The chemical composition of the ASTM A322 Grade 8640 steel are as follows:
| Element | Min | Max |
|---|---|---|
| Copper (Cu) | - | 0.3500 |
| Aluminum (Al) | - | 0.0600 |
| Molybdenum (Mo) | 0.1500 | 0.2500 |
| Nickel (Ni) | 0.4000 | 0.7000 |
| Chromium (Cr) | 0.4000 | 0.6000 |
| PhOsphorus (P) | - | 0.0350 |
| Sulfur (S) | - | 0.0400 |
| Manganese (Mn) | 0.7500 | 1.0000 |
| Silicon (Si) | 0.1500 | 0.3500 |
| Carbon (C) | 0.3800 | 0.4300 |
ASTM A322 Grade 8640 Material Mechanical Properties
Each grade of ASTM A322 Grade 8640 has different mechanical properties. These properties are associated with specific levels of strength and a reduction in yield strength. Generally, Grade I is the weakest of the grades, providing the lowest levels of yield strength. At the same time, Grade V has the highest yield strength, which makes it the most suitable for applications requiring extra strength. An important property to consider when selecting a grade of ASTM A322 Grade 8640 is the percentage of elongation, which is the amount the material will stretch before it breaks.
The mechanical properties of the ASTM A322 Grade 8640 steel are as follows:
| YieldRp0.2 | ≤ 248 (MPa) |
| TeileRm | ≤ 115 (MPa) |
| ImpactKV/Ku | 41(J) |
| ElongationA | 22% |
| Reduction in cross section on fractureZ | 13% |
| As-Heat-Treated Condition | Solution and Aging, Annealing, Ausaging, Q+T,etc |
| Brinell hardness (HBW) | 211 |
ASTM A322 Grade 8640 Material Thermal Properties
The thermal performance parameters of the ASTM A322 Grade 8640 steel are as follows:
| Temperature (°C) | 21 | 453 | 259 |
| Modulus of elasticity (GPa) | - | 369 | - |
| Mean coefficient of thermal expaion ×10-6/(°C) | - | - | 32 |
| Thermal conductivity (W/m·°C) | - | 41.3 | 32.2 |
| Specific thermal capacity (J/kg·°C) | - | 413 | - |
| Specific electrical resistivity (Ω mm²/m) | 0.14 | - | - |
| Deity (kg/dm³) | - | - | 441 |
| Poisson’s coefficient, ν | - | - | 314 |
ASTM A322 Grade 8640 Material Machining Technology
ASTM A322 Grade 8640 steel is not typically heat treated, as it exhibits good strength and machinability as-delivered. However, it can be through-hardened or sub-critical treated to acquire superior strength and toughness.