Method for increasing proportion of special grain boundaries in precipitation strengthened austenitic heat-resistance steel

A technology of austenitic heat-resistant steel and special grain boundary, applied in the field of metals and alloys, it can solve the problems of not considering the competitive process of precipitation and recrystallization, the reduction of recrystallization energy, and the poor implementation effect, so as to increase the cumulative potential. The effect of fault and strain storage energy, increasing the content of special grain boundaries, and optimizing high temperature performance

Active Publication Date: 2015-12-23
ANYANG INST OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The technical problem solved in the present invention is: to overcome the competitive process of precipitation and recrystallization that is not considered in the prior art, the prec

Method used

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  • Method for increasing proportion of special grain boundaries in precipitation strengthened austenitic heat-resistance steel
  • Method for increasing proportion of special grain boundaries in precipitation strengthened austenitic heat-resistance steel
  • Method for increasing proportion of special grain boundaries in precipitation strengthened austenitic heat-resistance steel

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Experimental program
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Effect test

Embodiment 1

[0023] Example 1. The improved 310 austenitic heat-resistant steel in the hot-rolled state is subjected to grain boundary optimization treatment, and its nominal chemical composition is: 25Cr, 20Ni, 0.1C, 0Mn, 2.0Mo, 0.65Si, 0.2Ti, 0.2Zr, 0.15W, 0.15V, the average grain size of the hot-rolled state is 30μm.

[0024] The first step is to keep warm at 1200°C for 40 minutes, and then carry out rolling deformation at room temperature on a two-roll rolling mill with a deformation amount of 30%, which is completed in two passes; the second step is to hold at 1120°C for 20 minutes and then quench water to cool to room temperature, and then kept at 1120°C for another 40 minutes, quenched and cooled to room temperature; in the third step, spot-polishing and EBSD tests were performed on the treated samples, and analyzed by HKL-Channel5 software. The contents of different grain boundaries are shown in Table 1 As shown, the content of Σ≤29 special grain boundaries reaches 86.24%; its dist...

Embodiment 2

[0025] Example 2 The above methods (1) to (3) were adopted, and after the sample was kept at 1230° C. for 30 minutes for solid solution, it was subjected to 40% room temperature cold rolling. This was followed by 2 cycles of recrystallization annealing at 1150°C. EBSD observation was carried out on the tissue, and the EBSD pictures were analyzed with the help of HKL-Channel5 software. The results are as follows: image 3 shown. The distribution of different special grain boundaries is relatively uniform, and the content of grain boundaries whose content Σ≤29 is 83.15% (see Table 1, different grain boundary contents (number ratio, %) of each example steel).

Embodiment 3

[0026] Example 3 According to the above method, the improved 310 stainless steel was subjected to grain boundary optimization treatment. The nominal chemical composition of the steel is: Fe-25Cr-20Ni-0.2T-0.2Zr-0.1W-0.15V-2.0Mn-0.65Si-0.1C (wt.%), and the sample is solidified at 1250°C for 40 minutes Afterwards, 50% room temperature cold rolling was carried out. Subsequently, one cycle of recrystallization annealing was performed at 1200°C. EBSD observation was carried out on its tissue, and the results were as follows: Figure 4 shown. The uniformity of the microstructure is better, and the sum of the number percentages of different grain boundary types is higher, reaching 86.33%.

[0027] Table 1

[0028]

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Abstract

The invention belongs to the field of precipitation strengthened austenitic heat-resistance steel and relates to a method for increasing the proportion of special grain boundaries in the precipitation strengthened austenitic heat-resistance steel. An optimization treatment process includes solid solution, cold rolling and annealing. The method is characterized in that solution treatment is performed at the temperature from 1150 DEG C to 1300 DEG C for 20 min to 60 min; indoor temperature rolling with the deformation ranging from 20% to 60% is then performed, the single pass reduction is not lower than 15%, and then at the temperature from 1100 DEG C to 1250 DEG C, periodical short-time annealing and water cooling are performed. After optimization treatment is performed, the special grain boundaries in a microscopic structure of the precipitation strengthened austenitic heat-resistance steel are evenly distributed, and the proportion is higher than 80%. By the adoption of the method, the strain storage energy is improved by increasing the indoor temperature deformation, recrystallization is promoted to occur in precipitation strengthened austenitic steel, the proportion of the special grain boundaries in the precipitation strengthened high-Cr and high-Ni austenitic heat-resistance steel is increased, the performance of the steel related to the grain boundaries is optimized, and corrosion resistance and irradiation swelling resistance are particularly optimized.

Description

technical field [0001] The invention is applicable to austenitic heat-resistant steel strengthened by dispersed precipitates, and metals and alloys with a face-centered cubic (Face Centered Cubic, fcc) structure. In particular, a technical method is provided for increasing the grain boundary content of low ΣCSL (Coincidence Site Lattice, CSL) special structure in austenitic heat-resistant steel, and the invention belongs to the technical field of deformation and heat treatment. Background technique [0002] The development of clean and efficient fourth-generation supercritical water-cooled conceptual reactors and ultra-supercritical thermal power generation systems will contribute to the reduction of CO 2 It is of great significance to reduce emissions and alleviate the energy crisis. The service environment of high temperature, high pressure and water vapor puts forward higher requirements on the high temperature corrosion resistance and thermal strength of materials. At ...

Claims

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Application Information

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IPC IPC(8): C21D8/02C21D6/00C22C38/58C22C38/50C22C38/46C22C38/44C22C38/40
Inventor 孙红英周张健何强杨海杰王志刚翟雁来彦玲段非刘嵩杨建军廉萌萌
Owner ANYANG INST OF TECH
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