Cold-rolled shifting fork steel member for automobile and producing method

Abstract

The invention discloses a cold-rolled shifting fork steel member for an automobile and a producing method. The cold-rolled shifting fork steel member is characterized by comprising the steel chemical ingredients, by weight percentage, of 0.20-0.35% of C, 0.10-0.35% of Si, 0.50-1.50% of Mn, 0.40-1.50% of Cr, 0.0030-0.0070% of Ca, 0.0008-0.005% of B, 0.40-1.10% of Ni, 0.015-0.030% of Als, 0.015-0.040% of Nb, 0.015-0.030% of Ti, smaller than or equal to 0.15% of P, smaller than or equal to 0.008% of S, the balanced of Fe and unavoidable impurities. By means of appropriate hot rolling, cold rolling and cover annealing, the excellent accurate stamping performance can be achieved. The shifting fork portion is quenched and tempered, so that the hardness of the work portion of the shifting fork portion is greatly improved, and the service life of the shifting fork portion is prolonged.

Description

technical field [0001] The invention relates to the technical field of steel for automobile parts, in particular to a cold-rolled shift fork steel component for automobiles and a production method. Background technique [0002] Clutch release forks and shift forks of modern automobiles require complex shapes, high surface hardness after local high-frequency quenching, and good matrix toughness. The traditional methods of producing shift forks mainly include: (1) pouring blank → forging molding → normalizing → cold forming → machining → partial high-frequency quenching → tempering → cleaning. (2) Casting steel base → surface coating alloy modification treatment → finishing → surface heat treatment quenching and tempering. This type of method has low production efficiency, high cost and unstable product quality. [0003] However, using high-precision hot-rolled or cold-rolled steel strips to manufacture automobile clutch release shift forks by blanking method has the advanta...

AI Technical Summary

Problems solved by technology

[0005] However, the material described in Patent Document 1 is difficult to meet the surface hardness required by the shift fork. The shift fork teeth must be subjected to high-frequency quenching and tempering to obtain HRC ≥ 48 requirements. The material is mainly made of fine ferrite. Bulk grain strengthening provides high strength, but it cannot provide high surface hardness. At the same time, once the surface is quenched and tempered, the grains will inevitably increase and the strength will decrease.

Images