A high-strength rafm steel with optimized composition and its heat treatment process

Abstract

The present invention proposes a composition-optimized high-strength RAFM steel (low activation ferritic martensitic steel) and its heat treatment process. The mass percentage of each alloy element in the raw material of RAFM steel is: 0.10%≤C≤0.13%, 8.50%≤Cr≤9.00%, 1.80%≤W≤2.00%, 0.20%≤V≤0.25%, 0.15%≤Ta≤0.20%, 0.01%≤Zr≤0.02%, 0.45%≤Mn≤0.50%, 0.2% ≤ Si ≤ 0.4%, 0.02% ≤ N ≤ 0.04%, RE (rare earth element) ≤ 0.03%, O < 0.004%, P < 0.004%, S < 0.004%, the balance is Fe matrix; the purpose of increasing the content of Ta is In order to form a large number of dispersed second phases, at the same time, it can refine the grains and improve the toughness of the material; trace amounts of Zr and RE can improve the toughness of the material. The heat treatment method of the RAFM steel is as follows: first put it in a high-temperature furnace at 985±5°C, keep it warm for 60 minutes after the furnace temperature is stable, then put it out of the furnace and put it in a salt bath at 275±1°C for 60 seconds (the purpose is to make the sample The internal and external temperature reaches the same), and then quickly put it into a high-temperature furnace at 500±5°C. After the furnace temperature is stable, it is kept for 25 minutes and then air-cooled to room temperature; finally, the combined heat treatment process of RAFM steel of the present invention does not significantly reduce its plasticity. A higher strength was obtained.

Description

technical field [0001] The invention belongs to the field of metal materials, and in particular relates to a composition-optimized high-strength RAFM steel and a heat treatment process thereof, and is a process method for effectively improving the room temperature and high temperature strength of the RAFM steel. Background technique [0002] The current worldwide demand for energy is increasing, which promotes nuclear energy as one of the main energy sources in the future. The economic reliability of nuclear energy has been well documented in currently operating reactors. The Fourth Generation International Advanced Nuclear Energy Forum proposed six advanced reactor types. These advanced nuclear energy systems have higher safety, economy, and environmental friendliness. Compared with operating commercial nuclear reactors, Generation IV reactors have higher operating temperatures and higher neutron doses, which pose major challenges for material selection, such as the need t...

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Problems solved by technology

Compared with the harsh service environment of the fourth-generation reactor, this performance still cannot meet the requirements, so it is urgent to improve the room temperature strength and high temperature strength of RAFM steel to meet the harsh working environment

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