Rare earth and carbon co-infiltration method in continuous furnace for automobile gearbox gear

Abstract

The continuous micro deformation RE-carbon co-penetrating process for gear of automobile gear box is realized via making the pre-treated workpiece enter the different regions with RE co-penetrant in continuous carbonizing furnace at 840-890 deg.c. The workpiece is made to enter successively region-I for preheating and pre-penetrating; region-II and region-III with carbon potential of 1.15-1.25 % for carbonizing; region-IV with carbon potential of 0.8-1.05 % for diffusion treatment; and region-V with carbon potential of 0.8-1.05 % for waiting for discharging and quenching. The present invention is one controllable low temperature RE high concentration gas carbonizing process capable of resulting in optimal metallurgical structure, and has the advantages of high carbonizing rate, high efficiency and low power consumption.

Description

Technical field:

[0001] The invention relates to a carburizing method, in particular to a carburizing method for car gearbox gears in a continuous carburizing furnace using a rare earth co-penetrating agent. Background technique:

[0002] At present, 20CrMnTi or 20CrMoH steel is generally used in automobile gearbox gears in my country. Since the size of 20CrMnTi steel changes greatly before and after carburizing, and the regularity is not strong and difficult to control, 20CrMoH (or 22CrMoH) steel is mainly used. If the deformation is not properly crafted, it will also fail to meet international standards. In order to meet the international standard, the gear grinding process has to be adopted, and the gear grinding is a low-efficiency and expensive process, which not only prolongs the production cycle, but also increases the production cost. As we all know, solving gear deformation is a systematic project, involving the smelting quality of steel, rolling of steel, forging a...