Heat Treatment Method of Carburized parts

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According to the structure of the parts, the service conditions, and the location of the process arrangement, the carburized parts can be heat treated by one of the following methods to achieve the best results.

1. Direct Quenching and Tempering

Features: Can not refine the grain of steel. The quenching deformation of the workpiece is large, the amount of retained austenite on the surface of the alloy steel carburized part is large, and the surface hardness is low. Scope of application: simple operation, low cost, used to process parts that are not deformed and impact load, suitable for gas carburizing and liquid carburizing processes.

2. Pre-cooling Direct Quenching (quenching temperature 800-850℃), Low Temperature Tempering

Features: It can reduce the quenching deformation of the workpiece, the amount of retained austenite in the infiltration layer can also be slightly reduced, the surface hardness is slightly increased, but the grain cannot be refined. Scope of application: It is easy to operate, and the workpiece is small in oxidation, decarburization and quenching deformation. It is widely used in various tools made of fine-grained steel.

3. One-time Heating and Quenching

Quenching Temperature 820-850℃ or 780-810℃, Tempering

Features: For those with higher core strength requirements, quenching at 820-850°C, low-carbon M in the core, and higher surface hardness requirements, quenching at 780-810°C can refine the grains. Scope of application: suitable for solid carburized carbon steel and low-alloy steel workpieces, gas and liquid carburized coarse-grained steels, some workpieces that are not suitable for direct quenching after carburization and parts that need to be machined after carburization.

4. Carburizing and Tempering at High temperature

One-time Heating and Quenching, Quenching Temperature 840-860℃, Low Temperature Tempering

Features: High temperature tempering decomposes M and residual A, and carbon and alloying elements in the carburized layer are precipitated in the form of carbides, which is convenient for cutting and reducing residual A after quenching. Scope of application: Mainly used for Cr-Ni alloy carburized workpieces.