真空自耗炉的锰、铜、氮易挥发元素含量控制

真空自耗炉是生产高品质特殊钢的重要终端设备,常有VIM-VAR、VIM-ESR-VAR 2种工艺。真空自耗熔炼过程中,常常伴随着锰、铜元素的挥发以及氮的去除。目前,现场仅凭经验确定金属母材的组分,然而真空自耗前后的锰、铜元素烧损并不遵循减法规律,尚不能精准控制真空自耗后的铸锭中锰、铜元素含量。针对现场对合金元素精准控制的迫切需求,基于冶金动力学解释了真空自耗炉中锰、铜、氮元素的挥发机理,指出铸锭中锰、铜、氮元素的含量与金属母材中锰、铜、氮元素的含量呈倍数关系。在苏州双金实业有限公司结晶器内径为450 mm的真空自耗炉中熔炼630不锈钢时,在8 000 A电流和26 V电压条件下,得到锰元素的挥发系数为61%~65%,铜元素的挥发系数为88%~92%。研究结果为真空自耗熔炼中挥发性元素的精准控制提供了参考。

Content control of Mn,Cu and N volatile elements in vacuum arc remelting furnace

Vacuum arc remelting furnace is an important terminal equipment for producing high-quality special steel, which often has two processes, namely VIM-VAR and VIM-ESR-VAR. In the process of vacuum arc remelting, the volatilization of Mn and Cu elements and the removal of N element are often accompanied. At present, the composition of base metal is determined only by experience, but the burning loss of Mn and Cu before and after vacuum consumption does not follow the subtraction law, and the content of Mn and Cu in ingot after vacuum consumption cannot be accurately controlled. Aiming at the urgent need for precise control of alloying elements on site, the volatilization mechanism of Mn, Cu and N elements in vacuum arc remelting furnace was explained based on metallurgical kinetics. It is pointed out that the content of Mn, Cu and N in ingot is multiple with the content of Mn, Cu and N in base metal. When 630 stainless steel was smelted in a vacuum arc remelting furnace with 450 mm inner diameter of crystallizer in Suzhou Shuangjin Industrial Co., Ltd., the volatilization coefficient of Mn was 61%-65% and that of copper was 88%-92% under the condition of 8 000 A current and 26 V voltage. The study result provides a reference for the precise control of volatile elements in vacuum arc remelting.