00Cr12Ni不锈钢焊接热影响区的组织及韧性

采用Gleeble3800热力模拟试验机模拟了00Cr12Ni不锈钢不同热输入下的焊接热循环.研究了热模拟试样的组织及冲击韧性.实验结果表明,焊接粗晶区晶粒大小和马氏体的体积分数均随热输入的增加而增加;细晶区组织以马氏体为主,有少量的铁素体,晶粒非常细小;焊接粗晶区试样的室温冲击功随热输入的增加而降低;不同热输入下,细晶区模拟试样均具有优良的冲击韧性;粗晶区冲击试样均为脆性断裂,而细晶区冲击试样均为韧性断裂;为得到组织细小、韧性优良的焊接热影响区,应尽量采用小的热输入规范.

Microstructure and Toughness of Welded 00Cr12Ni Stainless Steel in Heat-Affected Zone

Welding thermal cycle of 00Cr12Ni stainless steel with different heat inputs were simulated on Gleeble 3800 thermo-mechanical simulator to investigate the microstructure and impact toughness of the heat-affected zone (HAZ). The results showed that the grain size and martensite volume fraction in the coarse-grain heat-affected zone (CGHAZ) both increase with the heat input, while the microstructure of the fine-grain heat-affected zone (FGHAZ) consists mainly of martensites with a small content of ferrites. The impact work done in CGHAZ at room temperature decreases with increasing heat input, but in FGHAZ all specimens are of high impact toughness no matter how the heat input varies. The specimens all present brittle fracture in CGHAZ and present ductile fracture in FGHAZ. A conclusion is therefore drawn that the welding heat input should be scheduled as low as possible so as to obtain an HAZ where the fine grains and high toughness are both available.