1, choose the appropriate quenching medium According to the material, mechanical property requirements and shape size of forgings to choose suitable quenching medium and reasonable quenching operation method, to have appropriate cooling characteristics. Under the precondition of guaranteeing quenching effect, the quenching medium with slow cooling capacity is chosen to prevent quenching deformation and quenching cracking caused by too fast cooling ability of quenching medium.
When quenching and cooling, the proper cooling speed and cooling time should be controlled. Since the heat quenching temperature of forging is higher than the ordinary quenching temperature, quenching after Gao temperature deformation, the hardenability of the forged heat quenching parts is good, so the N22 of carbon steel and alloy steel forging waste heat quenching is generally chosen. N32 oil as quenching medium.
The oil temperature of quenching parts is generally 100℃?110℃.
Oil is easy to aging, smoke, environmental protection, can be used polymer quenching medium, including polyethylene glycol (PAG) quenching medium used more, its cooling performance, forgings good cooling uniformity, in the long-term use of performance more stable.
2, quenching cooling control The quenching groove of forging factory should have sufficient volume, and the continuous transmission belt should be configured, and its running speed can be adjusted to ensure the necessary cooling time. In addition, the quenching medium should be equipped with stirring system, cooling system and heating device, and the temperature control of quenching medium should be controlled to strictly control the temperature fluctuation range of quenching medium of forgings.
If it is oil, also should be equipped with quenching fume exhaust device.
3, regular monitoring, maintenance and maintenance
Forgings for quenching medium to be regularly monitored, maintained and maintained to ensure that the quenching medium has the required cooling performance. For fast quenching oil, the cooling capacity of oil should be measured regularly, and the ratio of oil should be adjusted accordingly.
No way to bring water into the rapid quenching oil, and regular precipitation, filtration, 淸 oil tank and the circulation of the oxide skin and other impurities, to maintain quenching oil cleaning.
For water-based quenching fluids (polymer quenching medium), in long-term mass production, the cooling characteristics of quenching fluids should be controlled according to the following methods. The quenching solution used by the forging factory must use the Viscosity method to measure the concentration. The viscosity meter is used to measure its kinematic viscosity once a week, and the concentration coefficient is converted.
In the forging production process, the quenching liquid refractive index is measured on time, and the concentration of the quenching liquid is obtained by multiplying the index by the concentration coefficient measured by the week. It is important to regularly measure the cooling capacity of quenching fluids. Because with the increase of the use time, the impurities in quenching medium increase, the medium aging and even metamorphism. It is unavoidable to increase the maximum cold speed and 300 ℃ of quenching liquid, and to reduce the temperature corresponding to the highest cooling rate, thus increasing the quenching tendency of forgings.
Technicians should adjust the concentration of quenching liquid according to the measurement result and the actual situation. Regular precipitation, filtration, cleaning tank and circulatory system of powder crumbs, rust and oxide skin and other impurities, to keep the quenching medium clean. Is strictly prohibited in any way to the oil-like substances in the quenching tank, if the forging quenching liquid in the mixture of oil-like substances, will lead to quenching agent failure. When the forging factory is not used for a long time, it should run the quenching agent circulatory system regularly to prevent anaerobic bacteria from quenching. Quenching agent in the production of bacteria will cause quenching liquid stink, black. If the quenching liquid is found to be smelly, blackening phenomenon, should be added to the fungicide in time to remove bacteria.