Chemical heat treatment method capable of obviously improving corrosion resistance of gear

Abstract

The invention belongs to a metal surface chemical heat treatment technology and aims to provide a chemical heat treatment method capable of obviously improving the corrosion resistance of a gear. According to the method, ion oxidation treatment is carried out on the gear which is subjected to ion nitriding, wherein air is used as an air source, the ion oxidation treatment and the ion nitriding are carried out in the same furnace; and after the ion nitriding is carried out on the gear at 560 DEG C, and air is introduced for oxidization for 0.25-1 hour after the temperature is reduced to 350-450 DEG C. According to the chemical heat treatment method, one layer of a dense oxidized film which mainly contains Fe3O4 is generated on the surface of a nitriding layer of the gear; under the same condition, compared with a gear sample which is not oxidized, the gear which is subjected to ion oxidization has the advantages that the corrosion resistance can be obviously improved and the surface rigidity gradient of the nitriding layer is obviously slowed down. The chemical heat treatment method is simple to operate; compared with other oxidization methods, the method provided by the invention has the advantages that no auxiliary equipment is used, an oxidization medium is air, and the oxidization temperature is low and the consumption of energy sources is reduced; moreover, the chemical heat treatment method has the advantages of low treatment cost, high production efficiency and the like.

Description

technical field [0001] The invention belongs to metal surface chemical heat treatment technology, and aims at a chemical heat treatment method for significantly improving the corrosion resistance of gears. Background technique [0002] Gears have good comprehensive performance. In order to meet their surface wear resistance, nitriding methods are usually used, mainly including: (1) ion nitriding; (2) salt bath nitriding; (3) gas nitriding, etc. Ion nitriding chemical heat treatment is the earliest developed technology with the widest application range. It has the advantages of uniform nitriding layer, high efficiency, less pollution, short processing time, and small workpiece deformation. It has become an indispensable part of many products. Missing surface strengthening process. [0003] However, in practical industrial applications, due to the complexity of the gear working environment, while improving the surface hardness of the gear, it is also necessary to take into ac...

AI Technical Summary

Problems solved by technology

[0003] However, in practical industrial applications, due to the complexity of the gear working environment, while improving the surface hardness of the gear, it is also necessary to take into account the electrochemical corrosion resistance of the surface. The ε phase is usually loose and porous on the surface of the gear after ion nitriding. Yes, an oxygen concentration battery is formed between the peak and the valley, and the oxygen deficiency in the valley is easily corroded, forming pitting corrosion, which reduces its electrochemical corrosion performance to a certain extent

And the nitrided layer is thin, brittle and easy to fall off

In order to overcome the above defects, salt bath oxidation, vacuum furnace oxidation, surface coating and other methods are generally used in actual production. The oxidation medium is mostly oxygen or hydrogen-oxygen mixture, the operation is complicated, and the processing cost is relatively high.

Images