| CPC C22C 1/02 (2013.01) [C22C 30/02 (2013.01)] | 7 Claims |
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1. A smelting method of an alloy with ultra-high N-content in a VIM furnace, characterized in that the smelting method in a VIM furnace comprises a smelting step carried out in a VIM furnace and a casting step;
the smelting step comprises a melting period and a refining period, and the later stage of the smelting refers to the later stage of the refining; and in the later stage of the smelting, nitrogen-containing substances are added to the VIM furnace to adjust the N content;
the nitrogen-containing substances are baking treated nitrogen-containing substances, wherein the baking temperature is 750-1100° C., and the baking time is ≥6 hour;
in the later stage of the smelting, before the addition of the nitrogen-containing substances, inert gases are introduced into the VIM furnace, wherein, the time from the addition of the nitrogen-containing substances to the start of the casting is 14-15 minutes, the inert gas is argon gas, and the pressure of the argon gas in the VIM furnace is ≥10000 pa,
in the smelting step, when raw materials are added to the VIM furnace before the smelting, the added amount of metallic chromium is 80-85% of the total mass of all the metallic chromium raw materials; the remaining 15-20% of the metallic chromium is added according to the required amount before the introduction of the inert gas in the later stage of the smelting to adjust the composition;
the composition of the alloy with ultra-high N content is as follows in terms of mass percentage: C: 0.02-0.10%; Cr: 23.00-27.00%; Ni: 35.00-39.00%; W: ≤0.50%; Mo: ≤1.00%; P: ≤0.04%; S: ≤0.03%; Mn: ≤1.50%; Si: ≤1.00%; B: ≤0.01%; Nb: 0.40-0.90%; Co: ≤3.00%; N: 0.15-0.30%; Al: ≤0.40%; Ti: ≤0.20%; Cu: ≤0.50%; and Fe: balance.
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