超低温下高韧性奥氏体不锈钢焊缝裂纹分析与控制

为解决超低温工况下高冲击韧性要求的厚壁奥氏体不锈钢根部焊道出现裂纹的情况，结合工程实例，分析了奥氏体不锈钢焊缝结晶裂纹的形成机理；从改善焊接接头设计、降低焊接热输入、控制焊道成型系数、提高焊缝铁素体含量等几个方面对焊接工艺进行了改进，从而降低焊缝出现结晶裂纹的倾向性；最后通过增加检测措施，确保所有受压元件及受力焊缝在整个厚度方向上全部进行无损检测，保证设备的焊接质量。

Analysis and Control of Welding Crack of Austenitic Stainless Steel with High Toughness at Ultra-low Temperature

In order to solve the crack in the root pass of thick wall austenitic stainless steel with high impact toughness under ultra-low temperature, combined with engineering examples, the formation mechanism of crystallization crack in austenitic stainless steel weld is analyzed. The welding process is improved from the aspects of improving the design of welding joint, reducing welding heat input, controlling weld bead forming coefficient and increasing the ferrite content of weld, so as to reduce the tendency of crystal crack in weld. Finally, add testing measures ensure that nondestructive testing is carried out on all pressure components and stressed welds in the whole thickness direction, so as to ensure the welding quality of the equipment.