Contribution to Comparison of Methods for Determining Welding Procedures for theAvoidance of Hydrogen Cracking

摘要

A comparison of methods for determining welding procedures for the avoidance ofhydrogen cracking during fabrication was made by Hart et al. for the International Institute of Welding (IIW Doc. IX-1602-90). Five published methods dealing with primary cracking parameters were used to assess safe welding conditions for two C-Mn steels. The paper contributes to the work by adding one more method to the comparison. The method, denoted as the VTT/OU method, was jointly developed and published in 1984 by the Technical Research Centre of Finland (VTT) and Osaka University, Japan (OU). Safe welding conditions were determined by the VTT/OU method corresponding to that in the paper of Hart et al. in terms of minimum arc energy without preheat, and minimum preheat for three arc energies: 1,2 and 3 kJ/mm. As parameters, the hydrogen level, joint type (butt and fillet) and plate thickness were varied. The VTT/OU method was shown to take a somewhat different stand from the others on the importance of crack-controlling factors. The joint geometry, especially with butt joints, is regarded as an essential factor affecting the level of precautions necessary.