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Method for improving low-activation ferrite/martensitic steel high-temperature oxidation resistance

A low-activation ferrite, high-temperature oxidation resistance technology, applied in the field of metal protection, can solve the problems of poor oxide film compactness and adhesion, weak high-temperature oxidation resistance, low Cr content, etc., to improve the high-temperature oxidation resistance. Effect

Inactive Publication Date: 2015-01-14
INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Low-activity ferritic / martensitic steel is used in a high-temperature environment with low Cr content, so the oxide film formed at high temperature has poor compactness and adhesion performance, resulting in weak high-temperature oxidation resistance of the material , thus affecting the use of materials

Method used

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  • Method for improving low-activation ferrite/martensitic steel high-temperature oxidation resistance
  • Method for improving low-activation ferrite/martensitic steel high-temperature oxidation resistance
  • Method for improving low-activation ferrite/martensitic steel high-temperature oxidation resistance

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Experimental program
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Effect test

Embodiment 1

[0022] 9CrWVTa low-activation ferrite / martensitic steel is used as the research material to illustrate the effect of the present invention on the high-temperature oxidation resistance of low-activation steel, and its composition is shown in Table 1. The heat treatment system of the material before SMGT is as follows: heat preservation at 1050°C for 1 hour with water quenching, heat preservation at 750°C for 2 hours in air cooling; cut the heat-treated material into rod-shaped samples with a diameter of 20 mm and a length greater than 100 mm, and prepare a center of one end of the sample. The tip hole with a diameter of 4mm; fix the prepared sample on the machine tool, first use the turning tool to turn the rod-shaped sample to the same axis, and then use the tungsten carbide indenter to perform SMGT; the processing technology is: single feed a p =20μm, the forward speed of the indenter V 1 =6mm / min, rod rotation speed V 2 =300rpm, and the number of repeated rolling is 3 times...

Embodiment 2

[0027] The heat treatment process of raw material is the same as embodiment 1, and the SMGT treatment process is: single feed rate a p =20μm, the forward speed of the indenter V 1 =2mm / min, rod rotation speed V 2 =300rpm, the number of repeated rolling is 3 times; the grain size on the surface of the sample after nanometerization is 30nm, but the surface of the sample appears to be chipped, that is, the surface is destroyed; after oxidation at 600°C for 500h, compared with Experimental Example 1, the SMGT sample The weight gain increases, and the thickness of the oxide layer increases, and the oxide layer is looser. Therefore, under this process, SMGT has little effect on the oxidation resistance.

Embodiment 3

[0029] The heat treatment process of raw material is the same as embodiment 1, and the SMGT treatment process is: single feed rate a p =2μm indenter forward speed V 1 =15mm / min, rod rotation speed V 2 =300rpm, the number of times of repeated rolling is 1 time; after treatment, no nano-gradient structure is formed on the surface of the sample; after being oxidized at 600°C for 500h, compared with Experimental Example 1, the weight gain and oxide layer thickness of the SMGT sample and the CG sample are similar, so in this Under the process, SMGT cannot improve the oxidation resistance of the material.

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Abstract

The invention aims at providing a method for improving low-activation ferrite / martensitic steel high-temperature oxidation resistance, and the method enables the ferrite / martensitic steel to satisfy service conditions. The method helps to improve the high-temperature oxidation resistance of the material by forming a nanocrystal-composed surface layer on the low-activation steel surface. Especially, by performing surface mechanical grinding treatment (SMGT) on the low-activation ferrite / martensitic steel subjected to high-temperature tempering, the crystal grain is fined, the crystal boundary ratio is increased, and the element diffusion rate is improved, and thus a protective oxidation film is rapidly formed and anti-oxidation effect is finally given play. The method is capable of substantially improving the high-temperature oxidation resistance of the material, thereby solving the problem that the usage temperature is relatively low.

Description

technical field [0001] The invention relates to metal protection technology, in particular to a method for improving the high-temperature oxidation resistance of low-activation ferrite / martensitic steel. Through surface mechanical rolling treatment (SMGT), a gradient structure varying from nanocrystalline, submicrocrystalline to microcrystalline is introduced on the surface of the material, greatly improving the oxidation resistance of low-activation ferrite / martensitic steel. Background technique [0002] Low-activation ferritic / martensitic steels are selected as candidate structural materials for future ADS spallation targets due to their superior properties such as low thermal expansion coefficient, high thermal conductivity, excellent resistance to radiation swelling and resistance to radiation brittleness. . This type of steel is formed by replacing elements such as Mo, Nb, and Ni in ordinary steel with low activation elements such as W, V, and Ta, and the main alloy c...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21D1/18C21D7/04
Inventor 戎利建卢柯王镇波宋元元鲁艳红
Owner INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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