高强度桥梁钢焊接冷裂纹敏感性研究

摘要

The weld cold cracking susceptibility of Q460q was studied through the cold cracking sensitivity index,the highest hardness of heat affected zone and oblique Y-groove test in this paper.The results show that cold cracking sensitivity index Pm of Q460q is 0.17%,preheat temperature that it does not produce cold cracks is 60 ℃;the maximum hardness of heat affected zone at ambient and preheat temperature are 282 HV and 271 HV.less than the maximum allowable hardness 410 HV;oblique Y-groove test that the weld surface crack is O.the average rate in the crack section is 7.8% at ambient temperature,the surface of welding seam and section of the crack rates are 0 at 60℃.Three experiments show that the weld cold cracking of Q460q is less sensitive.%通过冷裂纹敏感指数计算、热影响区最高硬度实验和斜Y型坡口实验分析了高强度桥梁钢Q460q的焊接冷裂纹敏感性.结果表明:Q460q冷裂纹敏感指数Pcm=0.17％,不产生冷裂纹的预热温度为60℃；常温和预热60℃条件下的热影响区最高硬度分别为282 HV和271 HV,均小于最大允许硬度410 HV;斜Y型坡口实验在室温条件下焊接时,焊缝表面裂纹率为0,平均断面裂纹率为7.8％,在60℃预热条件下焊接时,焊缝表面和断面裂纹率均为0.以上三种实验结果均表明高强度桥梁钢Q460q焊接冷裂纹敏感性较低.