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 present invention is a control method in the field of heat treatment technology, especially for 9CR18 thin -wall bearings. Background technique [0002] During the heat treatment process of the 9CR18 thin -walled bearing circles, the size and shape change will occur due to thermal stress and tissue stress. Especially after quenching, the inner and outer diameter of the 9CR18 thin -walled bearings will increase, and it will easily produce ellipse or conical deformation. [0003] Generally speaking, the quenching horse austency is larger than that of other tissues, and the workpieces after quenching have increased volume.The temperature gradient formed due to the different heating and cooling of the workpiece, which generates thermal stress and organizational stress. In addition, the intensity of the workpiece is reduced in the heat.The workpiece is distorted or warped, which is the root cause of quenching deformation. [0004] In addition, mechanical for...

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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 problem of 9Cr18 The deformation problem caused by quenching of thin-walled bearing rings, the roundness of the bearing rings after quenching is good, which can greatly reduce the grinding allowance of bearing rings, reduce the grinding workload, and improve the grinding efficiency

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