This investigation introduces two new techniques to quantitatively address the challenging problem of understanding Hydrogen Induced Cracking (HIC) in welding processes. The first technique is a novel procedure to create a known and controlled HIC in a welded sample. The second is an in-process monitoring technique to measure the initial formation and subsequent growth of the HIC in a multi-pass weld whilst being compatible with the high temperatures associated with the welding process. The HIC was initiated using a localised quenching method of the weld and its character was verified using both macrograph and microscopic investigations. During HIC initiation and growth, the sample was monitored every 1–30 min for a total of 96 h using a custom non-destructive testing (NDT) system, mounted on a robot which ensured repeatable inspection positioning. Combining these techniques has therefore allowed for the first time, a detailed understanding of the evolution of HIC in a multi-pass welded sample. Our findings reveal that the HIC was initiated 43 min after the weld ended and that it then grew rapidly for about 15 min and continued growing at a slower rate for around 24 h. No significant growth was observed for the remaining 72 h of the experimental measurement.

这项研究引入了两种新技术，以定量解决在焊接过程中理解氢致裂纹（HIC）的挑战性问题。第一种技术是在焊接样品中创建已知且受控的HIC的新颖方法。第二种是一种过程中监视技术，用于测量多道次焊缝中HIC的初始形成和随后的生长，同时与与焊接过程相关的高温兼容。HIC是使用焊缝的局部淬火方法引发的，并通过宏观和微观研究验证了其特性。在HIC启动和生长期间，使用安装在机器人上的定制无损检测（NDT）系统，每1–30分钟对样品进行总共96 h的监测，以确保可重复的检查定位。因此，首次将这些技术结合起来就可以对多道次焊接样品中的HIC的演变进行详细的了解。我们的发现表明，HIC在焊缝结束43分钟后开始，然后迅速生长约15分钟，并以较慢的速度持续生长约24小时。在剩余的72小时的实验测量中未观察到明显的增长。