超长奥氏体不锈钢焊管光亮固溶处理工艺改进

Continuous Bright Solution Treatment Process Improvement for Overlength Austenitic Stainless Steel Welded Pipe

超长奥氏体类不锈钢焊接管连续光亮固溶热处理工艺受技术装备的制约,高温固溶时间不足,焊管在高温下金相组织转变不充分,导致奥氏体组织不纯、应力消除不彻底;急冷时间过长,存在Cr23C6被析出的可能,容易产生晶间腐蚀等质量问题。通过改造热处理设备,将传统的二段式改进为三段式光亮固溶热处理工艺,增加高温区保温恒温段,以提高奥氏体组织纯度、消除应力;同时缩短急冷时间,防止Cr23C6在奥氏体晶界析出,使奥氏体类不锈钢焊管得到理想的组织和性能。

The continuous bright solution heat treatment process for overlength austenitic stainless steel welded pipe is restricted by technology and equipment,the high temperature solution time is insufficient,and the metallographic microstructure transformation of welded pipe in high temperature is not sufficient,which lead to impure austenite, stress release is not complete;Rapid cooling time is too long,the Cr23C6 components may precipitate,the main quality problems of intergranular corrosion easily appear. Through improving heat treatment equipment, the traditional two section type of bright solution heat treatment process is enhanced to three section type ,increase insulation constant temperature in high temperature region, in order to improve the purity of austenitic organization and eliminate stress. At the same time to shorten the rapid cooling time,in order to prevent the Cr23C6 components precipitating in the austenite grain boundary, the ideal microstructure and properties of austenitic stainless steel welded pipe can be obtained.