Knowledge

The influence of high-frequency quenching on the internal structure of metals is multi-faceted, specifically manifested in the following aspects:

I. Surface Microstructure Changes

After high-frequency quenching treatment, the surface of metal workpieces is rapidly heated to a high temperature and then quickly cooled. During this intense temperature change process, austenite rapidly transforms into martensite, significantly increasing the hardness of the surface microstructure. This increase in hardness not only enhances the wear resistance of the workpiece but also significantly improves its fatigue resistance. This change in surface microstructure is the core mechanism by which high-frequency quenching improves the surface performance of workpieces, enabling them to maintain excellent performance even under high load and high wear conditions.

II. Residual Austenite and Carbides

During the high-frequency quenching process, due to the extremely rapid heating and cooling rates, a certain amount of austenite may remain within the metal. These residual austenites may further transform into martensite during subsequent cooling or in service, thereby continuously affecting the hardness and stability of the workpiece. Additionally, the carbides within the metal may dissolve and redistribute under the high-temperature conditions of high-frequency quenching. Such changes in carbides not only influence the microstructure of the metal but also have significant impacts on its mechanical properties and corrosion resistance.

III. Grain Size and Morphology

During high-frequency quenching, the size and morphology of grains within the metal also undergo significant changes. The rapid heating and rapid cooling conditions may lead to grain refinement. The refined grains can significantly enhance the strength and toughness of the metal, enabling the workpiece to exhibit better comprehensive performance under complex stress conditions. However, if the heating time is too long or the temperature control is improper, it may also cause abnormal grain growth, which in turn reduces the mechanical properties of the metal and even leads to problems such as brittle fracture.

IV. Initial Austenite Grain Size and Martensite Block Size

After high-frequency quenching, the initial austenite grain size and martensite block size of metals are influenced by both the homogenization temperature and the amount of residual carbides. Generally, the higher the homogenization temperature, the larger the initial austenite grain size, which may have an adverse effect on the strength and toughness of the metal. Meanwhile, the amount of residual carbides affects the size and distribution of martensite blocks. Uneven distribution of carbides may lead to significant differences in the size of martensite blocks, thereby affecting the overall performance of the metal. These organizational changes are key factors that need to be precisely controlled in the high-frequency quenching process, directly determining the final performance of the metal workpiece.

In summary, high-frequency quenching, through its unique rapid heating and rapid cooling process, causes significant and beneficial changes in the surface structure of metal workpieces, significantly enhancing their hardness and wear resistance. At the same time, this process also has a profound impact on the residual austenite, carbides, grain size and morphology, as well as the initial austenite grain size and martensite block size within the metal. These complex organizational changes work together to ultimately determine the excellent performance of high-frequency quenched metal workpieces in various application scenarios.​​​​​​​

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