Sub-temperature carburizing heat treatment method for reducing heat treatment deformation of thin-wall gear

Abstract

The invention relates to a sub-temperature carburizing heat treatment method for reducing heat treatment deformation of a thin-wall gear. The method comprises the following steps of S1, pre-sub-temperature normalizing; S2, slow speed shot blasting; S3, sub-temperature carburization, specifically, gradient heating is adopted to a sub-temperature carburizing temperature, a two-stage carburizing method is adopted in the sub-temperature carburizing process, the first stage is a strong carburizing stage, and the second stage is a diffusion stage; S4, gradient slow cooling quenching, specifically, firstly, gradient slow cooling is carried out on a carburized thin-wall gear forging to 840-860 DEG C, heat preservation is carried out for about 1h, then the slow cooling is continuously carried out to 815-825 DEG C, the heat preservation is carried out for about 1h, the carbon potential in the furnace is controlled to be 0.5-0.05%, and then quenching is carried out in a polyvinyl alcohol solution; and S5, low-temperature tempering. According to the method, the deformation degree of a gear workpiece can be greatly reduced, the production qualification rate can be obviously improved, meanwhile,crystal grains can be effectively refined, the hardness and strength of a gear can be improved, the service life of the gear can be obviously prolonged, and in addition, the refined crystal grains can obviously improve the carburizing speed, reduce the process time and reduce the energy consumption.

Description

technical field [0001] The invention relates to the field of heat treatment, in particular to a sub-temperature carburizing heat treatment method for reducing heat treatment deformation of thin-walled gears. Background technique [0002] High-performance thin-walled gears are common transmission parts in machinery and are widely used in fields such as ships and aerospace vehicles. Due to its complex working environment and long-term exposure to large contact stress, alternating loads and impact loads, the precision and performance requirements of high-performance thin-walled gears are very high. At present, high-performance thin-walled gears mostly adopt the heat treatment method of direct quenching after carburizing with ordinary gas or secondary quenching after carburizing to meet the high hardness and high wear resistance of the surface of thin-walled gears. However, due to the large difference in thickness of various parts of the thin-walled gear, it is very sensitive t...

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Problems solved by technology

[0003] The technical problem to be solved by the present invention is to provide a sub-temperature carburizing heat treatment method for reducing heat treatment deformation of thin-walled gears, which can solve the problem of existing thin-walled gears while satisfying the high surface hardness and high wear resistance of thin-walled gears. The problem of large heat treatment deformation of gears

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