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, strong feasibility, and eliminate mixed crystal defects Effect

Active Publication Date: 2021-11-02
ANHUI UNIVERSITY OF TECHNOLOGY
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  • Abstract
  • Description
  • Claims
  • Application Information

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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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  • Method for eliminating mixed crystals in S31035 high-alloy austenitic heat-resistant steel
  • Method for eliminating mixed crystals in S31035 high-alloy austenitic heat-resistant steel
  • Method for eliminating mixed crystals in S31035 high-alloy austenitic heat-resistant steel

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Embodiment 1

[0037] The method for eliminating mixed crystals in the S31035 high-alloy austenitic heat-resistant steel of the present embodiment, the specific process 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 from S31035 steel pipe 20×20×20mm 3 Sample, effective thickness D = 20mm. Carry out chemical composition analysis and metallographic structure analysis, chemical composition result is shown in table 1, metallographic structure is as follows figure 1 As shown, very little content does not affect M 23 C 6 The P, S, and B contents calculated at the dissolution temperature are no longer calculated.

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

[0040]

[0041] (2) Calculate M 23 C 6 the melting temperature. By the chemical com...

Embodiment 2

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

[0048] (1) The experimental material is S31035 steel pipe φ120mm×35mm through the hot extrusion process, and 20×20×20mm is cut from the 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 is obtained by thermodynamic calculation software (JMatPro) M 23 C 6 The dissolution temperature (Tc) is 1080°C.

[0052] (3) Set the temperature of the heat treatment furnace at Tc-30=1050°C, raise the temperature of the heat treatment furnace to 1050°C, put the S31035 steel pipe sample into it, and the time is 0.8 times the effective thickness ...

Embodiment 3

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

[0058] (1) The experimental material is S31035 steel pipe φ120mm×35mm by hot extrusion process, cut from S31035 steel pipe 50×30×30mm 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) Obtain the chemical composition according to step (1), and calculate M by thermodynamic software 23 C 6 The dissolution temperature (Tc) is 1050°C.

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

[0063] (4) The S31035 steel pipe sam...

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Abstract

The invention discloses a method for eliminating mixed crystals in S31035 high-alloy austenitic heat-resistant steel, and belongs to the field of alloy steel processing technologies. On the basis of a conventional S31035 high-alloy austenitic heat-resistant steel pipe preparation technology including hot extrusion, cold rolling and high-temperature solution treatment, a cold rolling link is removed, and a hot rolling technology is introduced. The hot rolling temperature range is lower than the M23C6 dissolving temperature in a sample by 30-100 DEG C, in the hot rolling process, a continuous grain boundary phase M23C6 is separated out through strain induction, pinning is applied to the grain boundary, and growth of recrystallized grains is inhibited. After hot rolling, high-temperature solution treatment at the temperature of 1200-1220 DEG C is carried out, grain boundary precipitated phases M23C6 are completely re-dissolved, the structure is completely recrystallized, finally, the mixed crystals are eliminated, the grains are refined, and the structure is uniform. According to the method, the mixed crystals in the S31035 high-alloy austenite heat-resistant steel pipe can be effectively eliminated, the internal structure is improved, and the qualified rate of products is increased.

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 stations, the traditional austenitic heat-resistant steel cannot meet the work needs. Compared with Super304H, TP347HFG and HR3C austenitic heat-resistant steel, S31035 austenitic heat-resistant steel, with a nominal composition of Cr22Ni25W3Cu3CoMoNbN, has a higher chromium-nickel content, which is based on Fe-22Cr-25Ni type austenitic stainless steel , added tungsten, cobalt, copper, niobium, molybdenum, nitrogen and other elements, is a new type of high chromium, nickel austenitic heat-resistant steel, th...

Claims

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Application Information

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Patent Type & Authority Applications(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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