High-carbon chromium bearing steel wire rod production method free of pickling after spheroidizing annealing

Abstract

The invention belongs to the technical field of metal product production, and relates to a high-carbon chromium bearing steel wire rod production method free of pickling after spheroidizing annealing. The method comprises the steps that a continuous casting billet is obtained through converter smelting, LF refining, VD vacuum treatment and continuous casting; then, the continuous casting billet is subjected to heat insulation pit slow cooling, in-furnace heating, high-pressure water dephosphorization, controlled rolling, controlled cooling, collecting and packaging, finishing, and inspection; and finally spheroidizing annealing and drawing are performed. During annealing treatment, a hot-rolled wire rod is heated to 790-810 DEG C, cooled to 690-720 DEG C after heat preservation, cooled to 600-650 DEG C again after heat preservation at the cooling speed less than or equal to 20 DEG C / h, and finally discharged to be cooled. The wire rod is drawn without surface treatment to obtain a wire rod product. The thickness of the oxidized scale of the wire rod is increased to 14 microns or above, the proportion of Fe3O4 in the oxidized scale is increased to 30% or above from original 15-20%, the performance is good, and abnormal phenomena such as uneven carbides are not found.

Description

technical field [0001] The invention belongs to the technical field of metal product production, and in particular relates to a production method of pickling-free high-carbon chromium bearing steel wire after spheroidizing annealing. Background technique [0002] The carbon content of bearing steel is about 1.0%, which belongs to hypereutectoid steel, and is mainly used for processing rolling elements (balls, rollers, needle rollers) and ferrules. The microstructure is composed of flaky pearlite and carbide, with poor plasticity and low drawability. Therefore, it needs to be spheroidized and annealed before use to improve its processing performance. The production method of conventional bearing steel wire rod is that after the hot-rolled wire rod is spheroidized and annealed, surface treatment (pickling and phosphating) is required, and then wire drawing processing; this process has long production cycle, pickling pollution, cost advanced features. [0003] Therefore, it ...

AI Technical Summary

Problems solved by technology

[0005] The technical problem to be solved by the present invention is to improve the mechanical peeling rate of the scale of the bearing steel wire rod after drawing, to solve the problem of residual scale on the surface of the steel wire, and to improve the wire drawing performance and surface quality

Images