Research on the Effects of Welding-wire-related Factors Affecting Diffusible Hydrogen Content

Abstract

It is well-known that diffusible hydrogen strongly influences cold cracking. However, it isn't understood well what kinds of factors in welding consumables affect diffusible hydrogen in weld metal. For example, it is thought that seamed flux cored wire has more amount of diffusible hydrogen than seamless flux cored wire. This study pointed out a misunderstanding of diffusible hydrogen content generated by FCAW. As a result of investigation, there was no correlation between wire structure and diffusible hydrogen content. Furthermore, welding-wire-related factors on GMAW and FCAW were classified clearly into the follows. (a) Surface lubricant, (b) Initial moisture of flux and (c) Moisture absorbed after production. Various welding wires were prepared and measured the diffusible hydrogen content in order to compare the effect of the each factor. As a result, the most influential factor is (b). The second is (c). The effect of (a) is the smallest.