Brätz Oliver, Klett Jan, Wolf Thomas, Henkel Knuth-Michael, Maier Hans Jürgen, Hassel Thomas
Fraunhofer Institute for Large Structures in Production Engineering IGP, 18059 Rostock, Germany.
Institut für Werkstoffkunde (Materials Science), Leibniz University Hannover, 30823 Garbsen, Germany.
Materials (Basel). 2022 Feb 14;15(4):1417. doi: 10.3390/ma15041417.
Hydrogen-assisted cracking is a major challenge in underwater wet welding of high-strength steels with a carbon equivalent larger than 0.4 wt%. In dry welding processes, post-weld heat treatment can reduce the hardness in the heat-affected zone while simultaneously lowering the diffusible hydrogen concentration in the weldment. However, common heat treatments known from atmospheric welding under dry conditions are non-applicable in the wet environment. Induction heating could make a difference since the heat is generated directly in the workpiece. In the present study, the thermal input by using a commercial induction heating system under water was characterized first. Then, the effect of an additional induction heating was examined with respect to the resulting microstructure of weldments on structural steels with different strength and composition. Moreover, the diffusible hydrogen content in weld metal was analyzed by the carrier gas hot extraction method. Post-weld induction heating could reduce the diffusible hydrogen content by -34% in 30 m simulated water depth.
对于碳当量大于0.4 wt%的高强度钢，氢辅助开裂是水下湿法焊接中的一个主要挑战。在干法焊接工艺中，焊后热处理可以降低热影响区的硬度，同时降低焊件中的扩散氢浓度。然而，在干燥条件下的大气焊接中已知的常见热处理方法在潮湿环境中并不适用。感应加热可能会有所不同，因为热量是直接在工件中产生的。在本研究中，首先对在水下使用商用感应加热系统的热输入进行了表征。然后，研究了附加感应加热对不同强度和成分的结构钢焊件微观组织的影响。此外，采用载气热萃取法分析了焊缝金属中的扩散氢含量。在30米模拟水深下，焊后感应加热可使扩散氢含量降低34%。
