Carburizing and quenching heat treatment method

Abstract

The invention discloses a carburizing and quenching heat treatment method which is applied to gas carburizing and quenching production normally required by common low-carbon steel and low-carbon alloysteel workpieces. The carburizing and quenching heat treatment method specifically comprises the following steps of S1, firstly, putting the workpieces into a carburizing furnace, and strong carburizing section treatment and diffusion section treatment are performed on the workpieces in the carburizing furnace, wherein the carburizing temperature of the strong carburizing section treatment is 915DEG C-925 DEG C, the carbon potential of the strong carburizing section treatment is 1.1%-1.2%, the carburization temperature of the diffusion section treatment is 905 DEG C-915 DEG C, the carbon potential of the diffusion section treatment is 0.8%-0.9%, and the carburizing heat preservation time ratio of the strong carburizing section treatment to the diffusion section treatment is 11: 9; S2, performing cooling and quenching along with the carburizing furnace; S3, performing quenching oil cooling; and S4, performing tempering. By means of the method, the hardness and the hardened layer depthof the low-carbon alloy steel workpieces are guaranteed, meanwhile, it is guaranteed that the refined metallographic structure meets the national standard, and the carburizing and quenching quality is stably improved.

Description

Technical field:[0001]The present invention relates to a common low carbon steel, low-carbon alloy steel workpiece processing technology, in particular, a heat treatment method for carburizing quenching.Background technique:[0002]Steel carbon quenching is a common chemical heat treatment process, heats low-carbon steel, low-carbon alloy steel workpieces in a carburized medium, so that the carbon atom penetrates into the surface of the workpiece, and obtains a depth of seepage, after quenching And low-temperature tempering, enabling the surface layer of the workpiece to increase the surface hardness, abrasion resistance and fatigue strength of the workpiece, while the working parts are maintained in good toughness and plasticity of the original low carbon steel.[0003]The traditional carbon-free quenching process of ordinary carburized steel mainly has carbon-free temperature, direct quenching and carbon-free carbon, and then re-heats the quenching, while the carbon is lowered, direct...

AI Technical Summary

Problems solved by technology

[0003] The traditional carburizing and quenching process of ordinary carburizing steel mainly includes direct quenching after carburizing and air cooling or slow cooling after carburizing and then reheating and quenching. However, direct quenching after carburizing is easy to operate, high in efficiency and low in cost The advantages are widely used in production, but this process cannot refine the grains and structures of steel that are coarsened at high carburizing temperatures and for a long time. After quenching, bad structures such as coarse martensite often appear in the infiltrated layer, reducing toughness, etc. Mechanical properties, it is difficult to meet the performance requirements of the workpiece