Thermal treatment method for carrying out carburizing and quenching on low-carbon alloy steel workpiece

Abstract

The invention discloses a thermal treatment method for carrying out carburizing and quenching on a low-carbon alloy steel workpiece. The thermal treatment method comprises the steps that (1) after thesurface of the workpiece is cleaned, non-working surfaces of the workpiece are subjected to anti-seepage treatment; (2) after the workpiece is heated to a certain temperature, the temperature is maintained for a certain time, and then, the workpiece is subjected to carburizing treatment and diffusion treatment at the temperature; (3) then, the workpiece is cooled, and quenching is maintained; (4)a part is directly discharged and air-cooled; (5) after carbon layer turning and stress release tempering, the workpiece is quenched; (6) the workpiece is quenched in oil; and (7) finally, secondarylow-temperature tempering is carried out. According to the thermal treatment method, the workpiece processed and manufactured through low-carbon alloy steel is subjected to surface carburizing treatment, so that surface hardness of the workpiece is improved, carbide of a product is decreased, and the service life of the product is prolonged; besides, the carburizing and quenching technology of theproduct is improved, so that utilization performance of the product is improved; and the problem that the service life and utilization performance of the product are affected as carbide is redundantand too large in a traditional thermal treatment technology is solved, retained austenite on the surface of the product is decreased as much as possible under the precondition that performance of theproduct is guaranteed, and deformation of the product is controlled.

Description

technical field [0001] The invention relates to a heat treatment method for low-carbon alloy steel workpieces, in particular to a heat treatment method for carburizing and quenching low-carbon alloy steel workpieces. Background technique [0002] As we all know, the inner gear ring is a key component in mechanical equipment. It has the advantages of accurate transmission, compact structure, long service life, etc., and plays a key role in mechanical synchronization. This makes the precision of the inner gear ring extremely high, and the slight deviation of the inner gear ring's precision has a huge impact on the mechanical equipment. [0003] For a large internal gear ring, the surface load is relatively large when it is working, so the requirements for its surface hardness are very high, and the depth of the hardened layer is required to be deep. When the workpiece is working, the toughness of its core is very high, and the core of the product must also have sufficient str...

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Problems solved by technology

[0006] This process has the following disadvantages: 1. When the low-carbon alloy steel is lower than 500 °C after carburizing, the product is prone to generate a large amount of carbides, and the product is prone to fracture when there are a large number of carbides.

2. When the carburizing carburizing potential is high, it will also bring the danger of excessive carbides

3. If the temperature of quenching and heat preservation is too low, it is difficult to improve the core hardness of the product and reduce the service life of the product, while the temperature is too high will increase the paralysis of the product surface, reduce the surface hardness of the product, and increase the hardness of the product. Deformation of large products

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