GB/T 699 40-A Introduce
Steel is one of the most widely used materials in the world, used for a variety of applications from construction to transportation. GB/T 699 40-A is a popular alloy steel used for a variety of purposes, from precision machining to general engineering use. GB/T 699 40-A is an alloy which is made up of two different types of steel: high-carbon steel and low-carbon steel. The high-carbon steel is used for the formation of the "matrix" of the metal; this contains the majority of the chemical elements listed above. The low-carbon steel is added for strength and is found mainly in the "alloying" elements. This combination of high-carbon and low-carbon steel creates a metal that is stronger and more durable than either type of steel alone.
Smelting temperature:1592°C - 1283°C
Application:High quality carbon structural steel
GB/T 699 40-A Material Mechanical Properties
The mechanical properties of the GB/T 699 40-A steel are as follows:
| YieldRp0.2 | ≤ 718 (MPa) |
| TeileRm | ≤ 722 (MPa) |
| ImpactKV/Ku | 33(J) |
| ElongationA | 31% |
| Reduction in cross section on fractureZ | 21% |
| As-Heat-Treated Condition | Solution and Aging, Annealing, Ausaging, Q+T,etc |
| Brinell hardness (HBW) | 414 |
GB/T 699 40-A Material Thermal Properties
The thermal performance parameters of the GB/T 699 40-A steel are as follows:
| Temperature (°C) | 34 | 972 | 591 |
| Modulus of elasticity (GPa) | - | 935 | - |
| Mean coefficient of thermal expaion ×10-6/(°C) | - | - | 43 |
| Thermal conductivity (W/m·°C) | - | 23.3 | 14.2 |
| Specific thermal capacity (J/kg·°C) | - | 312 | - |
| Specific electrical resistivity (Ω mm²/m) | 0.31 | - | - |
| Deity (kg/dm³) | - | - | 221 |
| Poisson’s coefficient, ν | - | - | 314 |
GB/T 699 40-A Material Machining Technology
Machining of GB/T 699 40-A steel typically requires a combination of diverse machining processes for quality production of more complex components. China being the biggest steel producers in the world, manufactures and supplies GB/T 699 40-A steel, which is a high-quality carbon structural steel. This type of steel is machinable and is suitable for the manufacture of automotive parts, machine tools, and many other machines. Typically, GB/T 699 40-A steel is used extensively in the manufacture of machinery and tools, as it is strong, durable and has excellent corrosion resistance.