多丝埋弧焊管焊接接头硬度与冲击韧性统计分析

Statistical Analysis on Hardness and Impact Toughness of Multiple Wire Submerged Arc Welded Pipe Joint

采用统计分析方法对多丝埋弧焊管母材、焊缝及HAZ显微硬度和冲击韧性变化规律进行了分析,主要探讨X70钢级多丝埋弧焊管焊缝及母材区域的随机硬度分布规律,并对同种钢级不同钢厂生产的X70钢管冲击韧性分布做了对比。结果表明,不同钢厂生产的X70多丝埋弧焊管母材、焊缝显微硬度均具有较好的正态分布规律,热影响区则由于化学成分和组织性能上有较大的不均匀性,其随机硬度数据也不符合严格的正态分布,容易成为其焊接的薄弱环节。利用统计学知识可以对不同钢厂母材的硬度及夏比冲击韧性进行评价,为多丝埋弧焊管质量及工艺分析提供一种新的思路。

The change rules of base metal, weld, HAZ microhardness and Charpy impact toughness of multi-wire SAW pipe were analyzed using statistical methods, the random hardness distribution law of the X70 multi-wire SAW pipe weld and base metal was discussed, and the Charpy impact energy distribution of X70 steel pipe produced by different factories were compared. The results indicated that the microhardness of weld and base metal of X70 multi-wire SAW pipe, which produced by different steel makers,is with better normal distribution. But the HAZ microhardness doesn＇t obey the normal distribution due to large inhomogeneities in the chemical compositions and performance, which easily becomes to be the weak link in welding. Adopting statistical knowledge to evaluate base metal hardness and Charpy impact toughness for different steel makers, will provide a new idea for multi-wire SAW pipe quality and process analysis.