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What is high frequency quenching and tempering?

There are many professional terminology for the treatment of more than five materials such as steel. The following small series introduces what is the function of high frequency quenching and tempering and its function of high frequency quenching and tempering. What is the purpose of the high-frequency quenching and tempering treatment of steel, the following small series for everyone to introduce in detail.
What is the meaning of high frequency quenching and tempering:
Both are heat treatment processes for metal materials.
High frequency quenching
Dongguan Haitu heats the workpiece of the metal material to a specific temperature for a certain period of time, followed by a heat treatment process of the rapidly cooled metal material immersed in the quenching medium. Common quenching media are brine, water, mineral oil, air, and the like. High-frequency quenching can improve the hardness and wear resistance of metal material products, so it is widely used in various types of tools, molds, measuring tools and parts that require surface wear resistance (such as gears, rolls, carburized parts, etc.).
Through the combination of high-frequency quenching and tempering at different temperatures, the strength, toughness and fatigue strength of metal materials can be greatly improved, and some properties can be obtained closely with each other (comprehensive mechanical properties) to meet different needs. Claim. In addition, high-frequency quenching can also obtain certain physical and chemical properties of certain special properties of steel, such as high-frequency quenching, so that permanent magnet steel enhances its ferromagnetism, stainless steel improves its corrosion resistance. The quenching process is mainly used for steel parts.
When the common steel is heated above the critical temperature, the original or at room temperature will transform all or most of the microstructure into austenite. Immediately after immersing the steel in water or oil, it rapidly cools and the austenite transforms into martensite. Martensite hardness is the highest compared to other tissues in steel. The purpose of high-frequency quenching of steel is to transform all or most of its microstructure into martensite, obtain high hardness, and then temper at the corresponding temperature to make the product workpiece have the expected performance.
Rapid cooling during induction hardening causes internal stresses in the internal structure of the product. When it is large enough, the product workpiece will be distorted or even cracked. Therefore, the proper cooling method must be selected. According to the cooling method, the quenching process is divided into four types: single-liquid induction hardening, double-medium induction hardening, martensite grading quenching and bainite isothermal induction quenching.
What is high frequency quenching and tempering?

The quenched workpiece product is again heated to a suitable temperature below the lower critical temperature, and heat treated for a period of time after cooling in a medium such as air or water or oil.
The steel workpiece product has the following characteristics after quenching: 1 It has an unbalanced (ie unstable) structure such as martensite, bainite and retained austenite. 2 There is a relatively large internal stress. 3 The mechanical properties of the material could not meet the requirements. Therefore, steel workpiece products generally need to be tempered after quenching.
The key to the role of tempering is: 1 to improve the stability of the structure, so that the workpiece product will not undergo another structural change during use, so that the geometric shape and performance of the workpiece product remain stable.
2 Eliminate internal stress, improve the performance of the workpiece product and stabilize the geometric shape of the workpiece. 3 Adjust the mechanical properties of steel materials to meet the requirements of use.
The reason why tempering has some effect is because the atomic activity is enhanced when the temperature is raised, and the atoms of iron, carbon and other alloying elements in steel can be diffused faster, and the atoms can be rearranged and combined, thereby Unstable imbalances gradually change into stable, balanced organizations. The elimination of internal stress is also related to the decrease in metal strength at elevated temperatures. In general, when steel is tempered, the hardness and strength are lowered, and the plasticity is improved. The higher the tempering temperature, the greater the change in the mechanical properties of some materials. Some alloy steels with a high content of alloying elements will precipitate some fine metal compounds when tempered in a certain temperature range, which will increase the strength and hardness. This phenomenon is called secondary hardening.
Requirement Different workpiece products should be tempered at different temperatures to meet the requirements of use. 1 Tools, bearings, carburized and quenched parts, surface hardened parts are usually tempered at a low temperature below 250 °C. After low temperature tempering, the hardness does not change much, the internal stress decreases, and the toughness is slightly improved. 2 The spring is tempered at 350-500 ° C at medium temperature to obtain high elasticity and necessary toughness.
3 Parts made of medium carbon structural steel are usually tempered at a high temperature of 500 to 600 ° C to obtain a good fit of strength and toughness. The heat treatment process of quenching and high temperature tempering is collectively referred to as quenching and tempering.
Why does steel have to be tempered after quenching? After quenching, the surface hardness is high, followed by tempering is to increase the strength.

Dongguan Haituo Electromechanical Equipment Co., Ltd. is a manufacturer of medium and high frequency induction heating equipment developed earlier in China. It is a high-tech private enterprise specializing in R&D, design, manufacturing, sales and service. enterprise. With a strong technical R & D team, experienced, customized automatic induction heating equipment according to the workpiece and process, free to provide customers with personalized process solutions. As well as a comprehensive after-sales service system in various parts of the country, we have won the trust of many famous domestic enterprises, and have the experience of providing quality products and services to them. Welcome to visit the company.
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