16MnR低合金高强钢埋弧自动焊结晶裂纹产生原因分析和防止

Analysis and prevention of crystal crack cause of 16MnR low alloy high strength steel by submerged arc automatic welding

在16MnR低合金钢埋弧自动焊工艺评定中,焊缝根部焊道纵向分布热裂纹沿奥氏体晶界开裂,属典型的结晶裂纹,它是由于结晶过程中S、P共晶物的偏析所引起。经过对比试验,母材、焊材化学成分均符合要求,且焊材H08MnA对结晶裂纹的敏感性低;通过焊接速度、焊接电流与裂纹率关系的试验分析可知,降低焊接速度或减小焊接电流均可减小结晶裂纹的产生;综合分析焊接线能量,确定了第一层施焊在较小线能量情况下,采用低焊速的方法能有效地防止结晶裂纹的产生;采用开槽引收弧板,点固焊距焊缝120 mm以上,有利于避免端部热裂纹产生。

In the evaluation of 16MnR low alloy steel submerged arc welding process,the root of weld bead longitudinal distribution of thermal cracks along the grain boundary of austenite crystal crack,it is due to the segregation of S, P eutectic crystallization process caused by. Through contrast test ,the parent metal, welding material chemical composition are in line with the requirements of welding consumables,and sensitivity of H08MnA on the crystallization of crack is low;the welding test current and crack rate of the welding, welding speed,reduce the welding current can be reduced or reduce the crystal cracks; after a comprehensive analysis of the wehting line energy,finally determined the first layer of welding line energy in smaller cases,generated by the decrease of welding speed to prevent crystal crack is effective; the slot guide arc plate,solid welding seam above 120 ram,to prevent hot crack tip.