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Forging method for controlling white point defects

A white spot and defect technology, which is applied in the forging field of controlling white spot defects, can solve problems such as white spot defects, and achieve the effect of controlling white spots and saving costs

Active Publication Date: 2020-07-28
PANGANG GROUP JIANGYOU CHANGCHENG SPECIAL STEEL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to provide a forging method for controlling white spot defects in order to overcome the problem of white spots in large forgings of white spot sensitive steel in the prior art

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0047] The forging method used in the production process of Cr5 series cold roll A1 includes the following steps:

[0048] (1) Heating the steel ingot at 1220°C, and performing the first forging by upsetting and drawing forging to obtain the intermediate billet;

[0049] (2) Air-cool the intermediate billet obtained in step (1) to 150-200°C, then temper and place it for 14 days, then perform a second forging at 1200°C, and then anneal to obtain the finished steel;

[0050] Wherein, the diameter of the intermediate blank is controlled to be 130% of the diameter of the finished product.

[0051] The obtained Cr5 series cold roll A1 basically has no white spots.

Embodiment 2

[0053] The forging method used in the production process of Cr5 series cold roll A2 includes the following steps:

[0054] (1) Heating the steel ingot at 1225°C, and performing the first forging by upsetting and drawing forging to obtain the intermediate billet;

[0055] (2) Air-cool the intermediate billet obtained in step (1) to 150-200°C, then temper and place it for 13 days, then perform a second forging at 1205°C, and then anneal to obtain the finished steel;

[0056] Wherein, the diameter of the intermediate blank is controlled to be 125% of the diameter of the finished product.

[0057] The obtained Cr5 series cold rolling roll A2 basically has no white spots.

Embodiment 3

[0059] The forging method used in the production process A3 of Cr5 series cold rolls includes the following steps:

[0060] (1) Heating the steel ingot at 1235°C, and performing the first forging by upsetting and drawing forging to obtain the intermediate billet;

[0061] (2) Air-cool the intermediate billet obtained in step (1) to 150-200°C, then temper and place it for 12 days, then perform a second forging at 1215°C, and then anneal to obtain the finished steel;

[0062] Wherein, the diameter of the intermediate blank is controlled to be 120% of the diameter of the finished product.

[0063] The obtained Cr5 series cold rolling roll A3 basically has no white spots.

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PUM

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Abstract

The invention relates to the field of steel materials, in particular to a forging method for controlling white point defects. The method comprises the following steps: (1) forging a steel ingot for the first time to obtain an intermediate blank; and (2) carrying out air cooling on the intermediate blank obtained in the step (1) to a preset temperature range, then carrying out tempering and placing, and then sequentially carrying out secondary forging and annealing to obtain finished steel, wherein, the diameter of the intermediate blank obtained in the step (1) is 120-150% of the diameter of the finished steel, and the preset temperature range is from the martensite start temperature to 50 DEG C below the martensite start temperature. According to the method, twice forming is carried out,the intermediate blank is forged firstly, poor stress conditions are produced after forging to induce the generation of white points in advance, the intermediate blank is forged to the finished product, and the white point defects are welded in the hot working process. The method can effectively control generation of white points and meanwhile can save cost.

Description

technical field [0001] The invention relates to the field of iron and steel materials, in particular to a forging method for controlling white spot defects. Background technique [0002] As we all know, white spot defect is one of the most harmful quality defects of steel. Once it is found, it can only be scrapped, and the economic loss is huge. At the same time, the occurrence of white spot has a certain lag. If it occurs during the service process of the material, it will cause great risk in use. [0003] The white spot sensitivity of steel depends on the composition and structure type of the steel, and is related to the cross-sectional size of the steel (the larger the end face, the stronger the white spot sensitivity), the hydrogen content in the steel is too high and the post-forging heat treatment process is not properly controlled. Excessive stress is the two main factors that cause white spots. [0004] The air humidity in Panzhihua, Sichuan is high, and it is diffi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B21J5/00B21J1/06C21D8/00
CPCB21J5/00B21J1/06C21D8/005C21D2211/009C21D2211/002C21D2211/008
Inventor 屈小科余多贤蔡武胡峰荣
Owner PANGANG GROUP JIANGYOU CHANGCHENG SPECIAL STEEL