双相不锈钢铸件气体敏感性机理新说

New Theory on Gas Sensitivity of Duplex Stainless Steels

以3A为代表的含N双相不锈钢,在铸造过程具有强烈的气孔敏感性,容易形成气孔。外籍铸造专家认为是材质本身含N所致。本文依据实物的气孔特征,提出新的敏感性成因机制,即双相不锈钢的结晶温度范围宽,属粥样凝固特性,铸件表面不易结壳而易结"膜",导致铸型中的水汽或涂料中的挥发气体侵入铸件形成气孔。否定了双相不锈钢的N气孔说法。该气孔形成机制用于现场实践得到验证,并提出克服气孔敏感的有效对策。

N2-containing duplex stainless steel signed as 3A possesses obvious gas sensitivity during casting process. Foreign specialists attribute the fault to the N2-containing. The author put forward a new theory on the basis of gas hole characteristic and the theory is verified in the practice. Some ways to deal with the problem of gas sensitivity is also provided.