Measurement of Diffusible Hydrogen in Steel Weldments-A Status Report

Hydrogen Assisted Cracking (HAC) is the most widely encountered cracking problem in the welding of ferritic steels. One of the methods to mitigate this type of cracking is to control and minimize the amount of diffusible hydrogen content in the welds. This, in turn, calls for standard test methods to measure diffusible hydrogen present in weldments made with different welding consumables, processes etc. This report describes test methods to measure diffusible hydrogen in the welds as per different International Standards. It also highlights the deficiencies in the present Indian Standard lor measurement of diffusible hydrogen and suggests revision of the standard to cover Submerged Arc Welding, Gas Metal Arc Welding and Flux Cored Arc Welding Processes in addition to Manual Meta! Arc Welding Process. It also recommends inclusion of Gas Chromatography Method and removal of glycerin method in the Bureau of Indian Standard (BIS) specifications.