Method for preventing cracking of water-quenched edges and angles of rectangular alloy steel member

A technology of alloy steel and corner cracking, which is applied in the direction of quenching agent, furnace type, heat treatment furnace, etc., and can solve problems such as stress increase

Active Publication Date: 2014-01-08
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 spraying method adopted by the invention fails to directly spray the end face of the quenched part, which is prone to edge and corner cracks. cracking problem

Method used

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  • Method for preventing cracking of water-quenched edges and angles of rectangular alloy steel member
  • Method for preventing cracking of water-quenched edges and angles of rectangular alloy steel member

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0043] The material to be processed is a medium-carbon alloy steel forging with a size of 5000 (length) * 1500 (width) * 200 (thickness) (mm). It is required that the mechanical properties of the position from the surface to 1 / 4 of the thickness after quenching are higher than the requirements.

[0044] Process: water-air alternately controlled quenching and cooling, the medium is water and air.

[0045] In order to avoid cracking at the edges and corners during the quenching and cooling process, the method (1) for preventing cracking at the edges and corners of rectangular alloy steel parts by water quenching according to the present invention is adopted, that is, the cooling rate of the surface areas other than the edges and corners is increased. , reduce the temperature difference between the surface area outside the edge and corner and the edge and corner, and reduce the tensile stress at the junction.

[0046] The specific method is to take rapid cooling measures on the s...

Embodiment 2

[0052] The material to be processed is medium carbon alloy steel, and the size is 5000 (length) * 1500 (width) * 200 (thickness) (mm). It is required that the mechanical properties of the position from the surface to 1 / 4 of the thickness after quenching are higher than the requirements.

[0053] Process: one-time immersion quenching and cooling. The quenching medium is: polymer water-soluble quenching medium

[0054] In order to avoid cracking at the sides and corners during quenching and cooling, the method (2) of the present invention for preventing cracks at the sides and corners of rectangular alloy steel parts by water quenching is adopted, namely: reduce the cooling rate at the sides and corners and reduce the size of the sides. , the temperature difference between the corner and the edge, and the surface area outside the angle, and reduce the tensile stress at the junction of the edge, angle and the edge, and the surface area outside the angle.

[0055] The specific me...

Embodiment 3

[0058] The material to be processed is medium carbon alloy steel, and the size is 5000 (length) * 1500 (width) * 200 (thickness) (mm). It is required that the mechanical properties of the position from the surface to 1 / 4 of the thickness after quenching are higher than the requirements.

[0059] Process: water-air alternately controlled quenching and cooling, the medium is water and air.

[0060] In order to avoid cracking of the edges and corners during the quenching and cooling process, the method (3) of the present invention for preventing cracking of the edges and corners of rectangular alloy steel parts by water quenching is adopted, that is, the self-tempering time is increased by setting the quenching and cooling process , reduce the supersaturation of carbon in the edge and angle martensite that has undergone martensitic transformation, and improve the ability of the edge and angle to resist cracking.

[0061] The specific method is to properly prolong the air cooling ...

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Abstract

The invention provides a method for preventing cracking of water-quenched edges and angles of a rectangular alloy steel member. The method comprises the following approaches: (1) increasing the cooling rate of surface areas not including edges and angles, decreasing difference between the temperature of the surface areas without the edges and angles and the temperature of the edges and angles and reducing pulling stress at the junctions of the surface areas and the edges and angles; (2) decreasing the cooling rate of the edges and angles, reducing difference between the temperature of the edges and angles and the temperature of the surface areas without the edges and angles and reducing pulling stress at the junctions of the edges and angles and the surface areas; and (3) in a water-air alternative quenching process, prolonging air cooling time in first few times of water quenching to increase the self tempering degree of the edges and angles, reduce the supersaturation degree of carbon in martensite in edge and angle areas having undergone martensite transformation and improve anti-cracking capability of the junctions of the edges and angles and the surface areas. With the method provided by the invention, the rectangular alloy steel member has desired strength and toughness on the premise that cracking of the rectangular alloy steel member in the processes of water quenching and water-air alternative quenching is avoided.

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 edges and corners of a rectangular alloy steel piece through water quenching. 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 rectangular alloy steel parts, are quenched and cooled, and quenching cracks mostly appear at the sides (intersection lines of two surfaces) and corners (intersection points of three surfaces). These positions have better he...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21D1/18C21D1/56C21D6/00C21D9/00C21D11/00
Inventor 陈乃录左训伟戎咏华
Owner SHANGHAI JIAO TONG UNIV
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