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Method for preventing cracking of water quenching end faces of shaft alloy steel parts

An alloy steel, end face technology, applied in the furnace type, heat treatment equipment, furnace and other directions, can solve problems such as excessive stress and cracking, and achieve the effect of avoiding cracking

Active Publication Date: 2014-01-01
SHANGHAI JIAO TONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the actual application situation is that the water spray method adopted by the invention fails to directly spray the end face of the shaft, and the problem of cracking caused by excessive stress at the junction of the outer circle area of ​​the end face of the shaft and other parts of the end face has not been solved.

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  • Method for preventing cracking of water quenching end faces of shaft alloy steel parts
  • Method for preventing cracking of water quenching end faces of shaft alloy steel parts

Examples

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Effect test

Embodiment 1

[0038] The processing material is medium carbon alloy steel, the size of the shaft is Ф200*4500 (length) (mm), and the mechanical properties at 1 / 2 of the radius after quenching are required to be higher than the requirements.

[0039] Process: water-air alternately controlled quenching and cooling, the medium is water and air.

[0040]In order to avoid cracking in the outer circle area of ​​the end face during the quenching and cooling process, one of the methods for preventing cracking of the end face of shaft alloy steel parts in water quenching according to the present invention is adopted, that is, to increase the cooling rate of the end face except for the outer circle area of ​​the end face , reduce the temperature difference between the outer surface of the outer circle of the end face and the outer circle of the end face, and reduce the tensile stress at the junction.

[0041] The specific method is to increase the cooling intensity of the end face except for the oute...

Embodiment 2

[0045] The processing material is medium carbon alloy steel, the size of the shaft is Ф200*4500 (length) (mm), and the mechanical properties at 1 / 2 of the radius after quenching are required to be higher than the requirements.

[0046] Process: one-time immersion quenching and cooling. The quenching medium is: polymer water-soluble quenching medium

[0047] In order to avoid cracking in the outer circle area of ​​the end face during the quenching and cooling process, one of the methods for preventing cracking of the end face of shaft alloy steel parts in water quenching according to the present invention is adopted, that is, to reduce the cooling rate at the outer circle area of ​​the end face, and reduce its difference with The temperature difference between the outer surface of the outer circle of the end face reduces the tensile stress at the junction of the outer circle of the end face and the outer surface of the outer circle of the end face.

[0048] The specific method...

Embodiment 3

[0050] The processing material is medium carbon alloy steel, the size of the shaft is Ф200*4500 (length) (mm), and the mechanical properties at 1 / 2 of the radius after quenching are required to be higher than the requirements.

[0051] Process: water-air alternately controlled quenching and cooling, the medium is water and air.

[0052] In order to avoid cracking in the outer circle area of ​​the end face during the quenching and cooling process, one of the methods for preventing cracking of the end face of shaft alloy steel parts in water quenching according to the present invention is adopted, that is, by setting the quenching and cooling process, increasing the self-tempering time and reducing the The supersaturation of carbon in the martensite in the outer circle region of the end face that has undergone martensitic transformation improves the ability of the outer circle region of the end face to resist cracking.

[0053] The specific method is to appropriately prolong the...

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Abstract

The invention provides a method for preventing cracking of water quenching end faces of shaft alloy steel parts. The method comprises the following steps: (1) increasing the cooling speed of an end face except the excircle region of the end face, decreasing the temperature difference between the surface beyond the excircle region of the end face and the excircle region of the end face, and reducing the tensile stress at the junction between surface beyond the excircle region of the end face and the excircle region of the end face; (2) decreasing the cooling speed at the excircle region of the end face, decreasing the temperature difference between the excircle region of the end face and the surface beyond the excircle region of the end face, and reducing the tensile stress at the junction between the excircle region of the end face and the surface beyond the excircle region of the end face; and (3) in a water-air alternative quenching cooling process, prolonging the air cooling time of several times of primary water quenching procedures to increase the self-tempering degree of the excircle region of the end face, reduce the degree of supersaturation of carbon in martensite in the excircle region of the end face already occurring martensitic transformation and improve the anti-cracking ability of the junction between the excircle region of the end face and the surface beyond the excircle region of the end face.

Description

technical field [0001] The invention relates to the field of quenching and cooling for heat treatment, in particular to a method for preventing cracking of the water-quenched end face of a shaft-type alloy steel piece. Background technique [0002] Quenching cooling refers to the process of cooling the steel in the austenitic state at an appropriate speed to obtain the expected structure and properties. In addition to the changes in the structure and properties of steel during quenching and cooling, it is also accompanied by cracking and distortion. Quenching cracking will cause the quenched parts to be scrapped. Therefore, people adopt various methods to avoid the occurrence of quenching cracking. [0003] Quenched parts, especially shaft alloy steel parts, are quenched and cooled. During the quenching and cooling process, cracks mostly appear on the end face of the shaft, and the position is close to the outer circle (hereinafter referred to as: the outer circle area of ​...

Claims

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Application Information

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IPC IPC(8): C21D1/18C21D11/00C21D9/00
Inventor 陈乃录左训伟戎咏华
Owner SHANGHAI JIAO TONG UNIV
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