Carburizing has a long history and has been used as a steel-making technology since the days of sword forging. With the aim of high strength and wear resistance, we provide high-quality services in production bases in Japan and abroad for various material needs. Carburizing and quenching treatment is a common heat treatment process for metal materials. It can make the surface of the carburized workpiece obtain high hardness and improve its wear resistance. The main processes include low temperature tempering, pre-cooling direct quenching, primary heating and quenching, carburizing high temperature tempering, secondary quenching and cold treatment, and induction heating after carburizing.

Low temperature tempering can not refine the grains of the steel, the quenching deformation of the workpiece is large, the surface of the alloy steel carburized parts has a large amount of residual austenite, and the surface hardness is low. Simple operation and low cost. It is used to deal with parts with little deformation and impact load. It is suitable for gas carburizing and liquid carburizing processes.

Pre-cooling direct quenching, low temperature tempering, quenching temperature 800-850 ℃. The quenching deformation of the workpiece can be reduced, the amount of retained austenite in the infiltrated layer can also be slightly reduced, and the surface hardness is slightly increased, but the austenite grain does not change. The operation is simple, and the oxidation, decarburization and quenching deformation of the workpiece are small, and it is widely used in various tools for the manufacture of fine-grained steel.

One-time heating and quenching, low temperature tempering, quenching temperature 820-850 ℃ or 780-810 ℃. For those with higher requirements on the strength of the core, quenching at 820-850 ℃, the core is low carbon M, and the surface requires high hardness, quenching at 780-810 ℃ can refine the grains. It is suitable for carbon steel and low-alloy steel workpieces after solid carburization, coarse-grained steel with gas and liquid carburization, some workpieces that are not suitable for direct quenching after carburizing, and parts that need to be machined after carburizing.

The secondary quenching and low-temperature tempering mainly improve the structure of the infiltrated layer. When the performance of the core is not high, it can be quenched between Ac1 and Ac3 of the material. When the performance of the core is high, it should be quenched above Ac3. It is mainly used for important carburized parts with high requirements on mechanical properties, especially for coarse-grained steel. However, after carburizing, it needs to be heated twice at high temperature, which increases the deformation and oxidative decarburization of the workpiece, and the heat treatment process is more complicated.

Secondary quenching cold treatment Low temperature tempering is higher than Ac1 or Ac3 temperature quenching, and there is more residue on the surface of the high alloy. The cold treatment promotes the transformation to improve the surface hardness and wear resistance. Mainly used for high-alloy steel workpieces that are not machined after carburizing. After carburizing, induction heating quenching and low temperature tempering. The permeation layer and the tissue near the permeation layer can be refined. The quenching deformation is small, and the parts that are not allowed to harden do not need to be impermeable in advance.