Cold drawing method of special-shaped bearing steel bar material

Abstract

The invention discloses a cold drawing method of a special-shaped bearing steel bar material, which comprises the following steps: (1) stripping the surface; (2) pretreating the surface; (3) cold drawing pre-stage deformation, wherein the amount of pre-stage cold drawing deformation is controlled at 7-10%, the cold drawing speed is less than or equal to 80m / minute; (4) recrystallizing and annealing; (5) pretreating the surface after annealing; (6) cold drawing and moulding; wherein the cold drawing deformation is controlled at 30-45%, the cold drawing speed is less than or equal to 40m / minute. According to the invention, the current single stage cold drawing is improved to double stages cold drawing, the phenomena of napping and big embowed blade on the surface of special-shaped bearing steel bar material can be avoided during the cold drawing process, thereby the rolling yield of the bar material is enhanced.

Description

technical field [0001] The invention relates to a method for manufacturing metal rods, in particular to a cold drawing method for bearing rods. Background technique [0002] GCr15 chromium bearing steel is one of the main materials for manufacturing various bearings. GCr15 bearing steel is used to manufacture rolling elements or bushings on motors, machine tools, tractors, and general mining machinery. GCr15 cold-drawn bearing steel bars include round steel bars, equilateral hexagonal special-shaped bearing steel bars, and unequal-sided special-shaped bearing steel bars. One-way rolling bearing is a kind of bearing, widely used in textile machinery, food machinery, harvester, washing machine, machine tool and other equipment. The rolling elements used in one-way rolling bearings are one of the special-shaped bearing steel bars. [0003] For the special-shaped bearing steel bar used for rolling elements in one-way rolling bearings, the "surface quality" of the cold-drawn s...

AI Technical Summary

Problems solved by technology

[0005] The main disadvantages of the special-shaped bar for one-way rolling bearings produced by the cold drawing method of the above-mentioned special-shaped bearing steel bar are: the yield of the special-shaped bar is low, only about 58%, and the surface of the finished product often has roughening (polishing) After the bar, due to the improvement of the surface finish, the adhesion of the surface wetting agent decreases, after the cold-drawing deformation heat release, the lubrication system is destroyed, the cold-drawn bar sticks to the cold-drawing die, and the bite produces roughness); in addition , the cold-drawn bar has a big knife bend that cannot be straightened (during the plastic deformation process, the flow direction of the metal moves in the direction of the least resistance, and when the cold-drawing process changes from a round steel bar to a special-shaped bar, the stress distribution appears Unevenness, there is a large knife bending that cannot be straightened, the straightness cannot meet the requirements, and the straightening and bending phenomenon after forming occurs), resulting in the straightness of the bar not meeting the requirements

[0006] For the above-mentioned defects, the prior art adopts the lime-coating and baking process to eliminate the roughening phenomenon on the surface of the bar, and eliminates the bending of the big knife by increasing the reduction amount of the steel during straightening, but none of them can meet the requirements of normal production

Images