Foreign Hot Treatment Technology and Equipment
1 Introduction
The process of hot treatment is a widely-used method to enhance the properties of metals by heating them from room temperatures to particular temperatures, and holding them for a certain period of time before cooling them down. This alloying process enhances the physical and mechanical properties of items like tools, dies, other structural materials and their components. Although Europe and America are still using traditional heat treatment methods, countries like Japan and China are deploying innovative heat treatment solutions.
2 Heat Treatment Techniques
There are two primary categories of heat treatment that form the basis of any metal or alloy enhancement process: ‘hardening’ and ‘tempering’. The two types of heat treatment require different levels of heat, depending on the material and machinery being used.
Hardening process:
Hardening is a process of using high temperatures to increase the hardness and strength of metals and alloys. The process entails heating the material up to the highest heat level that can be used by the existing equipment. It could range from 620 to 900 deg C, depending on the material. Then, the cooled material was quenched in the liquid to cool down the process quickly.
Tempering process:
The second type of heat treatment is known as tempering. This process entails heating the metal or alloy to a slightly lower temperature and then cooling it down slowly to enhance the physical as well as mechanical properties of the item. As compared to hardening, tempering process requires slightly lower temperatures.
3 Heat Treatment Equipment
Heat treatment processes involve the use of several specialized equipment which help in improving the properties of metals and alloys. Some of the most commonly used equipment are gas-fired furnaces, electric furnaces, salt baths and vacuum furnaces.
Gas-fired furnaces:
Gas-fired furnaces are used commonly in heat treatment processes, to ensure uniform temperatures throughout the metal or alloy items. These furnaces are highly energy-efficient and cost-effective, and they can generate temperatures up to 2500 deg F (1371 deg C) without any difficulty.
Electric furnaces:
Another popular kind of heat treatment is the electric furnace. These furnaces are generally used for high temperature operations and are quite efficient in producing temperatures up to 2800 deg F (1538 deg C). Electric furnaces have a wide range of uses, including tempering of certain alloys, induction tempering and hardening of titanium alloys.
Salt baths:
Salt baths are a type of quenching and tempering process that are used in heat treatment equipment. This process involves immersing the material into a heated salt bath to improve the properties of the metal or alloy item. Salt baths can reach temperatures up to 1400 deg F (860 deg C).
Vacuum furnaces:
Vacuum furnaces are used to achieve a faster rate of cooling from the higher temperatures associated with heat treatment processes. They work on the principle of gradient of pressure and temperature across boundaries, and can reach temperatures up to 3000 deg F (1649 deg C).
4 Conclusion
In conclusion, heat treatment processes are used to enhance the properties of certain metals and alloys, like tools, dies and structural materials. This process requires the use of specialized equipment, like gas-fired furnaces, electric furnaces, salt baths and vacuum furnaces, to achieve desired outcomes. Hence, the choice of heat treatment equipment should be based on the specific requirements of the material or application.
