GB/T 699 85-A Introduce
The hardness of GB/T 699 85-A is usually measured by the Brinell Hardness Test. This test measures the resistance of the steel to surface indentations made by a small steel ball. GB/T 699 85-A has a Brinell Hardness of approximately 180-240 HBW. In terms of strength, GB/T 699 85-A has a tensile strength of approximately 420-520MPa, making it one of the strongest steel alloys available. This high strength and hardness makes it suitable for a wide range of applications, including precision machining, engineering tools, and automobiles.
Smelting temperature:1824°C - 1827°C
Application:High quality carbon structural steel
GB/T 699 85-A Material Chemical Composition
The chemical composition of the GB/T 699 85-A steel are as follows:
| Element | Min | Max |
|---|---|---|
| Copper (Cu) | - | 0.2500 |
| Nickel (Ni) | - | 0.3000 |
| Chromium (Cr) | - | 0.2500 |
| Sulfur (S) | - | 0.0300 |
| PhOsphorus (P) | - | 0.0300 |
| Manganese (Mn) | 0.5000 | 0.8000 |
| Silicon (Si) | 0.1700 | 0.3700 |
| Carbon (C) | 0.8200 | 0.9000 |
GB/T 699 85-A Material Mechanical Properties
The mechanical properties of the GB/T 699 85-A steel are as follows:
| YieldRp0.2 | ≤ 351 (MPa) |
| TeileRm | ≤ 437 (MPa) |
| ImpactKV/Ku | 11(J) |
| ElongationA | 24% |
| Reduction in cross section on fractureZ | 14% |
| As-Heat-Treated Condition | Solution and Aging, Annealing, Ausaging, Q+T,etc |
| Brinell hardness (HBW) | 323 |
GB/T 699 85-A Material Thermal Properties
The thermal performance parameters of the GB/T 699 85-A steel are as follows:
| Temperature (°C) | 11 | 687 | 977 |
| Modulus of elasticity (GPa) | - | 413 | - |
| Mean coefficient of thermal expaion ×10-6/(°C) | - | - | 23 |
| Thermal conductivity (W/m·°C) | - | 41.3 | 13.2 |
| Specific thermal capacity (J/kg·°C) | - | 343 | - |
| Specific electrical resistivity (Ω mm²/m) | 0.24 | - | - |
| Deity (kg/dm³) | - | - | 122 |
| Poisson’s coefficient, ν | - | - | 133 |
GB/T 699 85-A Material Machining Technology
Drilling is also commonly used to machine GB/T 699 85-A steel. This involves using a drill to make holes in the steel. Various types of drills, such as drills with carbide tips, are used to drill through the steel. To ensure accuracy, the correct drill bit size must be selected and the correct setting on the drill press must be used.