Control method for preventing deformation in quenching process of 9Cr18 thin-wall bearing ring

Abstract

The invention relates to a control method for preventing deformation in the quenching process of a 9Cr18 thin-wall bearing ring. The method comprises the following steps of: firstly designing an upper die (1) and a lower die (3) which have symmetrical structures; before quenching, loading the 9Cr18 thin-wall bearing ring (2) into a 45KW box-type heating furnace for preheating, wherein the preheating temperature is 850 DEG C, and the preheating time is 30 min; shifting the 9Cr18 thin-wall bearing ring into a 50KW high-temperature box-type heating furnace for heating, wherein the heating temperature is 1070 DEG C, and the time for keeping the temperature is 5 min; taking the 9Cr18 thin-wall bearing ring out, and placing the 9Cr18 thin-wall bearing ring on the lower die of the quenching die; covering the upper die of the quenching die, and fixing the upper die, the 9Cr18 thin-wall bearing ring and the lower die as a whole to be placed in quenching oil for quenching; separating the upper die and the lower die 3 min after quenching, and taking out the 9Cr18 thin-wall bearing ring. The qualification rate of the bearing ring quenched by adopting the invention reaches 98 percent, and the economic benefit is remarkable.

Description

technical field [0001] The invention belongs to the technical field of heat treatment, in particular to a control method for preventing deformation of a 9Cr18 thin-walled bearing ring during quenching treatment. Background technique [0002] 9Cr18 thin-walled bearing rings will undergo dimensional and shape changes due to thermal stress and tissue stress during heat treatment, especially after quenching, the inner and outer diameters of 9Cr18 thin-walled bearing rings will increase, and elliptical or taper deformation will easily occur. [0003] Generally speaking, the specific volume of quenched martensite is larger than that of other structures, and the volume of workpieces after quenching will increase. Due to the asynchronous heating and cooling of various parts of the workpiece, a temperature gradient is formed, resulting in thermal stress and tissue stress. In addition, the strength of the workpiece is reduced in the hot state, and the superposition of stress often exc...

AI Technical Summary

Problems solved by technology

[0006] In order to solve the above problems, the present invention proposes a control method for preventing deformation of 9Cr18 thin-walled bearing rings during quenching treatment. This control method effectively solves the deformation problem caused by quenching of 9Cr18 thin-walled bearing rings. After quenching, the bearing sleeve The roundness of the ring is good, which can greatly reduce the grinding allowance of the bearing ring, reduce the grinding workload, and improve the grinding efficiency

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