Gear steel and heat treatment method thereof

Abstract

The invention provides gear steel and a heat treatment method thereof. The gear steel comprises the following constituents: 0.19 to 0.21 percent of C; 0.23 to 0.30 percent of Si; 0.75 to 0.85 percent of Mn; 1.07 to 1.10 Cr; 0.19 to 0.21 percent of Mo; 0.03 to 0.05 percent of Ni; 0.03 to 0.09 percent of Cu; 0.020 or less percent of P; 0.012 to 0.020 percent of S; 0.010 to 0.030 percent of Al; 15 or less PPm of O; 30 to 60 PPm of N; and Fe and other inevitable elements in balancing amount. The constituents of the gear steel are scientific and reasonable, the technical problems in the prior art are solved, the advantages of narrow hardenability band and high austenite grain size grade are achieved.

Description

technical field [0001] The invention relates to metallurgical technology, in particular to a gear steel and a heat treatment method thereof. Background technique [0002] The gears of automobiles and motorcycles are mainly installed in gearboxes, reducers and differentials, and undertake the tasks of changing speed, output torque, and driving cars and motorcycles. When the gear is working, all the torque acts on the meshing teeth, and the gear bears a large bending stress and contact stress, and it acts on each tooth periodically, so that it bears the action of repeated alternating stress. During the process of meshing and transmitting torque, the gears will also slip relative to each other and generate friction. Especially due to different road conditions, environments, vehicle speeds, etc., the car needs to change gears frequently, so that the end of the gear is subjected to multiple impacts, overloads and strong impacts. Studies have shown that the hardenability design ...

AI Technical Summary

Problems solved by technology

Existing 20CrMoH steel composition control dispersion is large, the austenite grain size level

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