A kind of rare earth steel and its preparation method

Abstract

The invention discloses a rare earth steel and a preparation method thereof. In terms of mass percentage, the components of the rare earth steel include: C: 0.01%-0.05%, Si: 0.15%-0.3%, Mn: 0.4%-0.5%, Cr: 8% to 10%, W: 2% to 2.5%, V: 0.2% to 0.25%, Ta: 0.05% to 0.1%, Zr: 0.001% to 0.01%, Y 2 o 3 : 0.3% to 0.6%, the rest is Fe; during preparation, Cr, W, Ta, Fe, Si, Mn and Y are smelted into a metal mother liquor, and then CO as an oxidant is introduced into the alloy mother liquor 2 Mixed gas with Ar to oxidize Y to Y 2 o 3 , then add Zr, Alloy V and C, cast after melting; carry out electroslag remelting in the protective atmosphere for purification; austenitize the purified steel ingot, and then press process the steel ingot into a steel plate, Water cooling is carried out after the pressure working; heat treatment is carried out on the steel plate obtained by the pressure working, so that the yttrium nano-precipitation phase is precipitated in the steel plate, and the rare earth steel is obtained. The invention can produce RAFM steel through smelting and casting, can increase the output of RAFM steel, and simultaneously improve the high-temperature mechanical properties of RAFM steel.

Description

technical field [0001] The invention belongs to the field of iron and steel metallurgy, and in particular relates to a rare earth steel and a preparation method thereof. Background technique [0002] Low activation ferritic / martensitic steel (Reduced Activation Ferritic / Martensitic, RAFM) has the advantages of low activation, low radiation swelling rate, excellent mechanical properties, thermophysical properties and mature technical foundation, etc. The preferred structure of cladding structural materials for fusion reactors. The designed operating temperature range of RAFM steel is 325-550°C, which cannot meet the requirements of CFETR Phase II and future nuclear fusion reactors. In order to improve the high-temperature mechanical properties of RAFM steel, a high melting point rare earth oxide disperse phase (Y 2 o 3 ) to prepare ODS-RAFM steel has become a good solution. Y 2 o 3 The melting point of the oxide is 2417°C, which has good thermal stability and does not c...

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Problems solved by technology

At present, the main preparation method of ODS steel is powder metallurgy (Powder metallurgy, PM), but PM-ODS steel preparation technology has disadvantages such as complex process and low efficiency, powder is easily oxidized and polluted, poor economy and poor product reproducibility.

A nuclear fusion demonstration reactor needs to use about 3,500 tons of low-activation materials. Due to the lack of large-scale production equipment, it is difficult to produce such a large-scale ODS-RAFM steel by powder metallurgy. This shortcoming has also become a fatal flaw of ODS steel.

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