Cold cracking sensibility is severe problem in welding fabrication of large-scale steel structures. It is well-known that diffusible hydrogen strongly influences this cracking. However, it isn't understood well what kinds of factors in welding consumables affect diffusible hydrogen content. This study shows the effect of factors related to welding wire on diffusible hydrogen content in GMAVV and FCAW. Furthermore, it shows the effectiveness of "low-hydrogen welding process [1-2]" on each factor. The factors related to welding wire on diffusible hydrogen content are divided into the following classes. (a)Surface lubricant, (b)Initial moisture in flux and (c)Moisture absorbed after production. Some welding wires were prepared and measured the diffusible hydrogen content in the weld metal with the conventional and the low-hydrogen welding process. As results, the low-hydrogen welding process removed the influence of factor (a) and (c). About factor (b), there is a slight effect of the low-hydrogen welding process in seamless flux cored wire tests. However, a great effect of decreasing diffusible hydrogen content is obtained from in seamed wire tests. There is a possibility that welding operator or supervisor will be able to control the diffusible hydrogen content in weld metal by applying this welding process and solid or seamed flux cored wire.
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