Vacuum carburizing method for obtaining dispersed fine carbides

Abstract

The invention discloses a vacuum carburizing method for obtaining dispersed fine carbides. The vacuum carburizing method comprises a heating and heat preservation stage, a pulse carburizing stage, a carbide precipitation and spheroidizing stage and a quenching stage. The pulse carburizing stage refers to a high-concentration carburizing process in which carburizing / diffusion is alternated for multiple times, and a required surface carbon concentration gradient is formed; and the carbide precipitation and spheroidizing stage refers to immediately inflating to quickly cool the surface of a workpiece to a certain temperature above an Ac1 line and keeping the temperature for a period of time, so that carbides are precipitated in austenite and form dispersed distribution, and meanwhile, the workpiece reaches the quenching temperature by using the waste heat of the core part. According to the method, the structure performance and the deformation amount are both considered, on one hand, fine carbides which are high in carbon content (1%-1.5%) and are distributed in a dispersed mode are obtained, the effect that the outside is hard and the inside is tough is achieved, and on the other hand, quenching distortion is reduced, and size control is achieved; and the method is short in process time, high in carburizing efficiency, low in equipment operation cost, excellent in product surface performance and small in deformation, and the obdurability of the material is exerted to the maximum extent, so that the service performance of the workpiece is improved.

Description

technical field [0001] The invention relates to a vacuum carburizing heat treatment technology, in particular to a vacuum carburizing method for obtaining dispersed fine carbides. Background technique [0002] Heat treatment is a process technology that gives or improves the service performance of the workpiece by changing the microstructure inside the workpiece, or changing the chemical composition of the workpiece surface, and fully exploits the potential of the material. Heat treatment is a key core technology in the machinery manufacturing industry. With the continuous emphasis on heat treatment technology, the heat treatment industry has gradually developed from extensive to refined, and more attention has been paid to new processes, new technologies, improving product intrinsic quality, saving energy, reducing consumption and prolonging life. Focus on economic benefits, etc. [0003] For key parts such as gears and bearings, the key to improving the service performanc...

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Problems solved by technology

[0005] However, the vacuum low-pressure carburizing and high-pressure gas quenching technology in the prior art still has defects such as long process time, high equipment operation cost, poor product surface performance, and large deformation.

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