Smelting production method of low activation martensitic steel for fusion reactor

Abstract

The invention relates to a method for producing a low-activation martensitic steel for a fusion reactor by melting. The method comprises: step one, a charging material is smelted in a vacuum induction furnace: (1) when a vacuum degree is between 0.1 and 10 Pa, argon gas is passed through the vacuum induction furnace till the vacuum degree is between 0.005 and 0.08MPa, and a smelting temperature is between 1450 and 1650 DEG C; (2) alloys are added in sequence: firstly, pure Fe is melted; Cr and W are added into the furnace; then Ta and V are added into the furnace, and finally C and Mn are added into the furnace; simultaneously, the level of an oxygen content in the pure Fe is observed; before Cr is added, a little of C is added into the furnace for carrying out deoxidation treatment; (3) on-line detection is carried out to the compositions of alloy elements; the alloy elements are added according to a detection result; and (4) after the compositions are qualified, a mixture is cast under the vacuum at a casting temperature of between 1450 and 1550 DEG C. Step two, according to the compositions and the inner quality level of a cast ingot which is obtained by vacuum induction and melting, whether the cast ingot is remelted and refined in a vacuum electroslag remelting furnace or a common electroslag remelting furnace with argon protection. Step three, a needed CLAM steel bar material is prepared by the production of forging, cogging and hot rolling. The method has the characteristics of simple smelting operation, stable process and low production cost; the compositions and impurities of the produced CLAM steel meet the design requirement; and the method has no aliquation of the compositions and tissues and high degree of purity and is suitable for the application of the fusion reactor.

Description

technical field [0001] The invention belongs to the technical field of metal material processing, and relates to a method for smelting and preparing low-activation martensitic steel suitable for fusion reactors. Background technique [0002] China's low-activation martensitic steel CLAM is a fusion reactor structural material developed by the applicant with independent intellectual property rights. It belongs to high-purity martensitic steel and requires strict control of impurities. [0003] T91 / P91 steel is an improved commercial martensitic heat-resistant steel with good high-temperature heat strength and oxidation resistance. It is widely used in superheater and reheater pipes in power plant boilers. The steel requires high purity. (S ≤ 0.010wt%, P ≤ 0.020wt%). At present, the country mainly relies on imports. [0004] However, qualified CLAM steel cannot be prepared by electric arc furnace smelting process. The main reasons are: (1) Due to the smelting in a non-vacuum ...

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Problems solved by technology

[0004] However, qualified CLAM steel cannot be prepared by electric arc furnace smelting process. The main reasons are: (1) Due to the melting in a non-vacuum environment, the main alloying elements will produce a certain amount of burning loss, such as C is easy to oxidize, Mn is easy to volatilize, and Cr is easy to absorb N in the air is difficult to achieve precise control of the composition; (2) Since CLAM steel has extremely strict requirements on impurity elements, it is difficult to use traditional desulfurization, deoxidation and dephosphorization processes to achieve impurity elements such as O≤0.01%, P ≤0.005%, S≤0.005%, Al≤0.01% (mass percentage) control requirements

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