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A method for eliminating mixed crystals in s31035 high-alloy austenitic heat-resistant steel

A technology of austenitic heat-resistant steel and alloy, which is applied in metal rolling and other directions, can solve the problems of uneven structure of high-alloy austenitic heat-resistant stainless steel, achieve uniform structure, eliminate mixed crystal defects, and have strong feasibility Effect

Active Publication Date: 2022-06-21
ANHUI UNIVERSITY OF TECHNOLOGY
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] The purpose of the present invention is to overcome the problem that S31035 high-alloy austenitic heat-resistant steel is prone to mixed crystal defects in the prior art, and proposes to provide a method for eliminating mixed crystals in S31035 high-alloy austenitic heat-resistant steel, by designing a new Hot working and high-temperature solid solution process route, eliminate uneven microstructure and mixed crystal phenomenon of high-alloy austenitic heat-resistant stainless steel, and control grain size

Method used

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  • A method for eliminating mixed crystals in s31035 high-alloy austenitic heat-resistant steel
  • A method for eliminating mixed crystals in s31035 high-alloy austenitic heat-resistant steel
  • A method for eliminating mixed crystals in s31035 high-alloy austenitic heat-resistant steel

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Experimental program
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Effect test

Embodiment 1

[0037] The method for eliminating mixed crystals in the S31035 high-alloy austenitic heat-resistant steel of the present embodiment is as follows:

[0038] (1) The experimental material is S31035 steel pipe φ120mm×35mm. The S31035 steel pipe is prepared by the current conventional hot extrusion process. The specific process belongs to the existing conventional technology, and will not be repeated here. Cut 20×20×20mm from S31035 steel pipe 3 Sample, effective thickness D=20mm. The chemical composition analysis and metallographic structure analysis were carried out. The chemical composition results are shown in Table 1, and the metallographic structure is shown in Table 1. figure 1 shown, the content of which is very small and does not affect M 23 C 6 The content of P, S, and B calculated from the dissolution temperature is no longer calculated.

[0039] Table 1 Chemical composition (mass percentage content %)

[0040]

[0041] (2) Calculate M 23 C 6 the dissolution t...

Embodiment 2

[0047] The method for eliminating mixed crystals in the S31035 high-alloy austenitic heat-resistant steel of the present embodiment is as follows:

[0048] (1) The experimental material is S31035 steel pipe φ120mm×35mm through hot extrusion process, and 20×20×20mm is cut from S31035 steel pipe 3 Sample, effective thickness D=20mm. Carry out chemical composition analysis and metallographic structure analysis, as shown in the following table:

[0049] Table 2 Chemical composition (mass percentage content %)

[0050]

[0051] (2) Calculate M according to step (1) 23 C 6 The dissolution temperature of M was obtained by thermodynamic calculation software (JMatPro) 23 C 6 The dissolution temperature (Tc) of 1080°C.

[0052] (3) Set the temperature of the heat treatment furnace to Tc-30=1050°C, heat the heat treatment furnace to 1050°C, and put the S31035 steel pipe sample for 0.8 times the effective thickness of the sample (20mm), that is, 16min.

[0053] (4) After the S31...

Embodiment 3

[0057] The method for eliminating mixed crystals in the S31035 high-alloy austenitic heat-resistant steel of the present embodiment is as follows:

[0058] (1) The experimental material is S31035 steel pipe φ120mm×35mm through hot extrusion process, and 50×30×30mm is cut from S31035 steel pipe 3 Sample, effective thickness D=30mm. Carry out chemical composition analysis and metallographic structure analysis.

[0059] Table 3 Chemical composition (mass percentage content %)

[0060]

[0061] (2) According to step (1), the chemical composition is obtained, and M is calculated by thermodynamic software 23 C 6 The dissolution temperature (Tc) of 1050℃.

[0062] (3) Set the temperature of the heat treatment furnace to Tc-100=950°C, heat the heat treatment furnace to 950°C, and put in the S31035 steel pipe sample for 1.2 times the effective thickness (30mm) of the sample, that is, keep the temperature for 36 minutes.

[0063] (4) The S31035 steel pipe sample is rolled after ...

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Abstract

The invention discloses a method for eliminating mixed crystals in S31035 high-alloy austenitic heat-resistant steel, which belongs to the field of alloy steel processing technology. The present invention removes the cold rolling link on the basis of the conventional S31035 high-alloy austenitic heat-resistant steel pipe preparation process: hot extrusion → cold rolling → high temperature solution treatment, and introduces a hot rolling process. The hot rolling temperature range is 30°C-100°C lower than the M23C6 dissolution temperature in the sample. During the hot rolling process, the strain-induced continuous grain boundary phase M23C6 precipitates to pin the grain boundary and inhibit the growth of recrystallized grains. After hot rolling, it undergoes high-temperature solution treatment at 1200 ° C to 1220 ° C, and the grain boundary precipitates phase M 23 C 6 All re-dissolved, the structure is completely recrystallized, and finally the mixed crystals are eliminated, the grains are refined, and the structure is uniform. The method of the invention can effectively eliminate mixed crystals in the S31035 high-alloy austenitic heat-resistant steel pipe, improve the internal structure, and increase the pass rate of products.

Description

technical field [0001] The invention relates to the technical field of heat treatment of austenitic stainless steel, in particular to a method for eliminating mixed crystals in S31035 high-alloy austenitic heat-resistant steel. Background technique [0002] Traditional Super304H, TP347HFG and HR3C austenitic heat-resistant steels are widely used in ultra-supercritical thermal power generating units. With the increase of steam pressure and temperature in coal-fired power plants, traditional austenitic heat-resistant steel cannot meet the working needs. Compared with Super304H, TP347HFG and HR3C austenitic heat-resistant steel, S31035 austenitic heat-resistant steel, nominal composition Cr22Ni25W3Cu3CoMoNbN, has higher chromium and nickel content, is based on Fe-22Cr-25Ni type austenitic stainless steel , adding tungsten, cobalt, copper, niobium, molybdenum, nitrogen and other elements, is a new type of high chromium, nickel austenitic heat-resistant steel, this type of auste...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C21D1/18C21D6/00C21D8/00C22C38/00C22C38/02C22C38/04C22C38/42C22C38/44C22C38/48C22C38/52C22C38/54B21B23/00B21C37/06
CPCC21D8/005C22C38/02C22C38/04C22C38/44C22C38/52C22C38/42C22C38/48C22C38/001C22C38/54C21D6/004C21D6/005C21D6/007C21D6/008C21D1/18B21B23/00B21C37/06
Inventor 周红伟张启方良伟韦勇赵伟白凤梅何宜柱
Owner ANHUI UNIVERSITY OF TECHNOLOGY
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