Heat treatment process of high-chromium heat-resistant alloy

A heat-resistant alloy and process technology, which is applied in the heat treatment process field of high-chromium heat-resistant alloys, can solve the problems of reduced martensite stability, coarse grain boundary precipitated phase size, and reduced durability.

Active Publication Date: 2022-01-18
HUANENG POWER INTERNATIONAL +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

When the Cr content increases, it will often lead to the coarsening of the precipitated phase size at the grain boundary, the decrease of the stability of martensite, and the decrease of durability.

Method used

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  • Heat treatment process of high-chromium heat-resistant alloy
  • Heat treatment process of high-chromium heat-resistant alloy
  • Heat treatment process of high-chromium heat-resistant alloy

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0034] Step 1: The deformed heat-resistant alloy includes the following components by weight percentage, C: 0.08%, Cr: 13%, Ni: 1%, Mn: 10%, Si: 0.4%, B: 0.005%, Mo: 1 %, W: 5%, Cu: 1%, and the balance is Fe.

[0035] The melting temperature of the second phase at the grain boundary of the alloy was measured at 1102°C, and the complete austenitization temperature A was measured by thermal expansion method c3 is 700.6°C, such as figure 1 shown.

[0036] Heat the deformed heat-resistant alloy to 1120°C at a heating rate of 15°C / min, and keep it warm for 30 minutes to ensure that all precipitated phases are dissolved into the matrix for solid solution treatment, and then water-cooled to room temperature after completion. After solid solution treatment, the tissue such as figure 2 As shown, the volume fraction of austenite is 75-90%, and austenite contains a large number of twins;

[0037] Step 2: Heat the heat-resistant alloy after solution treatment to 680°C at a heating ra...

Embodiment 2

[0047] Step 1: The deformed heat-resistant alloy includes the following components by weight percentage, C: 0.08%, Cr: 15%, Ni: 1%, Mn: 10%, Si: 0.4%, B: 0.005%, Mo: 1 %, W: 5%, Cu: 1%, and the balance is Fe.

[0048] The melting temperature of the second phase at the grain boundary of the alloy was measured at 1108°C, and the complete austenitization temperature A was measured by thermal expansion method c3 It is 706°C. refer to figure 1 , heat the deformed heat-resistant alloy to 1110°C at a heating rate of 10°C / min, and keep it warm for 30 minutes to ensure that all precipitated phases dissolve into the matrix, and carry out solid solution treatment. After completion, water cool to room temperature;

[0049] Step 2: Heat the heat-resistant alloy after solution treatment to 675°C at a heating rate of 10°C / min, keep it warm for 12 hours, complete the aging treatment, and then cool it to room temperature. The obtained tissue is as follows: Figure 6 shown. The matrix struc...

Embodiment 3

[0051] Step 1: The deformed heat-resistant alloy includes the following components by weight percentage, C: 0.05%, Cr: 11.5%, Ni: 1.6%, Mn: 10%, Si: 0.3%, B: 0.007%, Mo: 1.5 %, W: 4%, Cu: 1.2%, Al: 1%, and the balance is Fe.

[0052] After measuring the dissolution temperature of the second phase of the alloy grain boundary at 1106°C, the complete austenitization temperature A of the heat-resistant alloy was measured by the thermal expansion method c3 It is 705°C. refer to figure 1 , heating the deformed heat-resistant alloy to 1120°C at a heating rate of 10°C / min, and holding it for 30 minutes to ensure that all precipitated phases are dissolved into the matrix, and carry out solid solution treatment. After completion, water cool to room temperature;

[0053] Step 2: Heat the heat-resistant alloy after solution treatment to 665° C. at a heating rate of 10° C. / min, keep it warm for 12 hours, complete the aging treatment, and then water-cool to room temperature. The obtained...

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Abstract

A heat treatment process of a high-chromium heat-resistant alloy comprises the following steps: heating a deformed heat-resistant alloy to a temperature 30 DEG C above a second phase dissolution temperature of a grain boundary, carrying out solution treatment for 30-120 minutes, and then cooling; and then heating till the temperature is 10-40 DEG C below the complete austenitizing temperature of the heat-resisting alloy, performing aging treatment for 4-12 h, and then cooling. A matrix structure obtained through heat treatment is an austenite and martensite double-phase structure, and the volume fraction of the austenite is 40-50%. Fine discontinuous precipitated phases are distributed on grain boundaries, are mainly precipitated along the adjacent grain boundaries of austenite and martensite, cover about 80% of the adjacent grain boundaries of austenite and martensite, and are not more than 200nm in width. A large number of fine precipitated phases are distributed in austenite grains, the average size is not larger than 2 microns, and the volume fraction of the fine precipitated phases accounts for 30% or above of austenite; and the double-phase hardness of austenite and martensite is not lower than 300 HV.

Description

technical field [0001] The invention relates to the field of heat treatment of heat-resistant alloys, in particular to a heat treatment process for high-chromium heat-resistant alloys. Background technique [0002] In order to cope with global warming and improve the ecological environment, it is necessary to actively carry out low-carbon emission reduction actions, and improving the parameters of thermal power units is one of the effective ways to reduce carbon dioxide emissions and improve thermal efficiency. The improvement of thermal power unit parameters has brought higher requirements for the selection of key high-temperature components of the boiler. [0003] At present, ultra-supercritical thermal power units in commercial operation mainly use 9Cr martensitic heat-resistant alloys such as P91, P92, and FB2. When the steam parameters are raised above 650°C, the 9Cr martensitic heat-resistant alloy can no longer meet the requirements of oxidation resistance and flue g...

Claims

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Application Information

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IPC IPC(8): C21D6/00C22C38/58C22C38/02C22C38/54C22C38/44C22C38/42C22C38/06C21D8/00
CPCC21D6/004C21D6/005C21D6/008C22C38/58C22C38/02C22C38/54C22C38/44C22C38/42C22C38/06C21D8/005C21D2211/008C21D2211/001Y02P10/20
Inventor 张鹏杨征严靖博袁勇谷月峰党莹樱鲁金涛黄锦阳
Owner HUANENG POWER INTERNATIONAL
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