What is the heat treatment process of Hexagon Socket Screw With Pad?

In the manufacturing process of Hexagon Socket Screw With Pad, heat treatment is a crucial link, which directly determines the mechanical properties of the screw, such as hardness, tensile strength and wear resistance. The heat treatment of screws usually includes annealing, quenching, tempering and other steps. These process steps can change the internal structure of the material and improve the strength and durability of the screw.

1. Annealing
Annealing is the first step of the heat treatment process in the production of hexagon socket screws with pads. The purpose is to reduce the hardness of the material, improve its processing properties, and make it easier to operate in subsequent processing and forming.
Process steps: The blank of the screw is heated to the recrystallization temperature (usually between 600℃-800℃) in the annealing furnace and maintained for a certain period of time to release the internal stress in the material, and then slowly cooled. This process can reduce the hardness of the metal, increase its plasticity, and improve the machinability of the metal.
Function: Through annealing, the grain structure of the screw material becomes more uniform, the plasticity of the metal is improved, and cracks or breakage during cold processing are avoided. At the same time, annealing also provides a good organizational foundation for subsequent quenching and tempering processes.

2. Quenching
Quenching is the most important step in the heat treatment process of the screw. It can greatly improve the hardness and strength of the material and enhance the bearing capacity of the screw.
Process steps: The screw is heated to above the phase change temperature (generally 850℃-900℃) in the quenching furnace, and then quickly immersed in a cooling medium (such as water, oil or air). This rapid cooling process causes the austenite structure in the material to quickly transform into a higher hardness martensite structure.
Function: After quenching, the hardness and tensile strength of the hexagon socket hexagonal washer screw are significantly improved, thereby improving its wear resistance and bearing capacity. The quenched screw has an extremely high surface hardness, which can effectively resist deformation and wear under high load. At the same time, the formation of martensitic structure also gives the screw good elasticity and toughness, and can maintain stable performance for a long time in a high stress environment.
Note: The quenching process has very strict requirements on temperature and cooling rate. Too high temperature or too fast cooling rate may cause the screw to become more brittle and prone to fracture; while too low temperature or insufficient cooling will cause the screw to have insufficient hardness. Therefore, precise control of process parameters is essential.

3. Tempering
Tempering is to eliminate the internal stress generated during the quenching process and further improve the toughness of the screw so that it has good impact resistance while maintaining high hardness.
Process steps: The screw is heated to a medium temperature (usually 200℃-500℃) lower than the quenching temperature in the tempering furnace, and maintained for a certain period of time, and then cooled naturally. Through tempering treatment, the hardness of the screw is slightly reduced, but the toughness is significantly improved.
Function: After quenching, there will be large internal stresses remaining in the screw, which is prone to fracture during use. Tempering can effectively release these internal stresses, while transforming the martensite structure into tempered martensite, thereby improving the comprehensive mechanical properties of the screw. Through tempering treatment, the hexagon socket hexagon washer screws not only maintain high strength and wear resistance, but also have good toughness and impact resistance, and can work stably for a long time under complex stress environments.

4. Surface hardening treatment
In addition to the conventional quenching and tempering processes, hexagon socket hexagon washer screws are sometimes subjected to surface hardening treatments, such as carburizing, nitriding and other processes. Surface hardening treatment can form a high-hardness film on the surface of the screw, further improving the wear resistance and corrosion resistance of the screw.
Carburizing treatment: The screw is exposed to a carbon-containing medium at high temperature, so that carbon elements penetrate into the surface to form high-hardness carbides. After carburizing treatment, the surface hardness of the screw is extremely high, but the inner layer still maintains a certain toughness and has good impact resistance.
Nitriding treatment: Nitriding is to introduce nitrogen elements into the surface of the screw to form a high-hardness nitride layer. Similar to carburizing, nitriding treatment can also significantly increase the surface hardness of the screw and improve its corrosion resistance.