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高硅奥氏体不锈钢00Cr20Ni24Si4Nb,是我国最新研究的耐浓硝腐蚀的新钢种。本文研究了此钢种焊接接头冷弯角度过低,于熔合线产生宏观可见裂纹的原因。采用不同焊接方法的焊接接头、高温水淬及模拟焊接热循环等试验方法进行了试验研究。通过光学显微镜及扫描电镜的观察,证实了熔合线晶界液化是由于焊接热作用而产生的,成为弯曲试验时熔合线过早开裂的原因。由焊接接头冷弯试验得知,采取小规范焊接,并选择适当的坡口形式,对于防止共晶组织的不利作用是有效的。
High-silicon austenitic stainless steel 00Cr20Ni24Si4Nb, is the latest study of our country resistant to corrosion of nitric acid steel. In this paper, the reason why the cold-rolled angle of welded joints of this kind of steel is too low and macroscopically visible cracks occur in the fusion line is studied. Adopting different welding methods, such as welding joint, high temperature water quenching and simulated welding thermal cycle, etc. Through the observation with light microscope and scanning electron microscope, it was confirmed that the liquefaction of the grain boundary of the fusion line was caused by the heat of welding and became the reason of the premature cracking of the fusion line during the bending test. It is known from the cold bending test of welded joints that using a small gauge weld and selecting the appropriate groove form is effective in preventing the adverse effect of the eutectic structure.