Carburized automobile gear steel

Automobile Carburized Gear Steel is mainly low-carbon alloy steel. With the development of automobile industry, low-alloy carburized steel with similar composition is gradually adopted for automobile gear steel in various countries, and is developing in the direction of high performance, long life, economy and productivity. Automobile Carburized Gear Steel includes Mn steel, Mo steel, Ni Mo steel and Ni Cr Mo steel series. The automobile gearbox is mainly made of Mo steel 4023; Ni-Cr-Mo steel grades 8620 and 8720 with low Ni content are mainly used for transmission gears and driving and driven gears of rear axle of medium-sized vehicles; The gear of heavy-duty truck adopts Ni Cr Mo steel 4320 with higher Ni content and Ni Cr Mo steel 8822 with higher Mo content, and the gear of individual heavy-duty truck adopts Ni Cr Mo-B steel 94b17.

1. Air Cooled Bainitic Steel

Air Cooled Bainitic Steel is a kind of non quenched and tempered steel. Due to its good air cooling hardenability, it can avoid the quenching process, which not only saves energy and reduces cost, but also avoids the defects such as deformation, cracking and decarburization caused by quenching. It has good cold and hot working performance and excellent strength toughness matching, so it can improve the quality and service life of automobile gears. Tianjin Shengchang Gear Co., Ltd. and Tianjin Institute of heat treatment jointly conducted an in-depth study on the application of low-carbon bainitic steel and its carburizing process in automobile gears. The results show that the carburizing process can not only reduce the amount of carburizing and improve the mechanical properties of car gears, but also improve the mechanical properties of car gears.

2. Quasi bainitic steel

Quasi bainitic steel is a non carbide or atypical bainitic structure composed of bainite, ferrite and retained austenite. It is a new type of automobile gear steel with good combination of strength and toughness, excellent carburizing characteristics and air cooling hardening. A series of quasi bainitic steels developed by Northwest University of technology have been widely used because of their advantages of high strength and toughness, simple process and low cost. In order to apply it to carburized parts, quasi bainite carburized carbon steel bz18q is designed and used in the fifth gear of an automobile output shaft. After carburizing oil is cooled, the furnace sample is evaluated and tested according to the relevant standards of automobile gear, and the results meet the relevant technical requirements. The quasi bainite carburized steel gear is loaded into the road test. The test results show that the cross ball distance of automobile gear basically has no change before and after the sports car, and the meshing tooth surface is smooth without pitting. This provides a theoretical basis for the use of quasi bainitic steel in the manufacture of automobile gears to replace some high-quality alloy carburized steel containing more nickel.

Scroll to Top