服役中管道焊接热影响区的临界硬度

摘要

Welds made onto in-service pipelines are particularly susceptible to hydrogen cracking. During qualification of welding procedures, limits are often imposed on heat-affected zone hardness as a way to avoid cracking. The hardness level below which hydrogen cracking does not occur is not a fixed value, but varies along with hydrogen content and chemical composition. The result indicated that the widely used utmost hardness of 350HV10 is feasible for some materials, but welding is conducted in high concentration hydrogen for low-carbon material, it should strictly limit hardness level to reduce risk of crack arising.%服役中的管道在焊接时容易引起氢致裂纹.为了防止裂纹的产生,在对焊接方法做质量评定时,要对焊接热影响区的硬度进行限制.而不会导致氢致裂纹的极限硬度并不是一个固定的值,它会随着焊接过程中的氢含量和焊接金属的化学成分的变化而变化.研究结果表明,广泛使用的350HV10极限硬度对于一些材料来说是可行的,但低碳材料在高浓度氢气中焊接时,还是要严格限制硬度水平,以降低裂缝出现的风险.