Nb-Cr X80管线钢冷裂敏感性分析-《焊管》

文章信息/Info

Title:: Cold Cracking Sensitivity Analysis of Nb-Cr X80 Grade Pipeline Steel

Author(s):: YIN Zhang-hua; XUE Zhen-kui; YAN Chen; (Pipeline Research Institute of CPP，Langfang 065001，Hebei，China)

Keywords:: Nb-Cr X80 grade linepipe steel; cold cracking sensitivity; evaluation

摘要:: 采用碳当量法、焊接冷裂纹敏感指数法、最高硬度HV₁₀（max）公式法、SHCCT曲线图、焊接热影响区最高硬度试验、斜Y形坡口对接裂纹试验、残余应力的数值模拟和插销试验评价了Nb-Cr X80管线钢产生冷裂纹的敏感性。理论分析与试验结果表明，Nb-Cr X80管线钢的冷裂倾向性较小。综合理论分析和试验数据，并考虑到管道安装焊接施工中钢管湿度高、装配拘束应力大的实际情况，认为Nb-Cr X80钢管0℃以上环境温度焊接时，采用低氢型焊接材料或进行根焊时预热温度≥50℃即可，采用纤维素型焊条进行根焊时预热温度≥100℃即可。

Abstract:: This paper evaluated cold cracking sensitivity of Nb-Cr X80 grade steel by the following methods,carbon equivalent,cold cracks sensitive index,the maximum hardness HV₁₀（max） formula,SHCCT curve, maximum hardness test of HAZ,shant Y-groove cracking test,the numerical simulation of residual stress test,implant test and so on.The theoretical analysis and experimental results showed that Nb-Cr X80 grade steel has the trends of low cold crack.Consideration of the above theoretical analysis and experimental data,taking into account high humidity in pipe and great assembling stress during installation of pipeline,it regarded that if ambient temperature is above 0℃,the preheat temperature ≥ 50℃ can be proposed for welding Nb-Cr X80 grade with lowhydrogen welding material or root welding,and the preheat temperature ≥100℃ can be used for welding Nb-Cr X80 grade with cellulose consumables on root bead.