CONTROL OF HYDROGEN ASSISTED CRACKING IN HIGH STRENGTH STEEL WELDS

In present research work, the modified Granjon implant test was performed to evaluate the susceptibility of AISI 8620 and AISI 304 steel towards the hydrogen assisted cracking (HAC). Glycerine methods was employed to measure the diffusible hydrogen level (HD) in deposited metal for both the steels. The weld bead was deposited by using the Shielded metal arc welding (SMAW) process with basic type electrodes. The hydrogen was intentionally introduced for the plate of the material AISI 304 by using an oil of grade SAE 10, which is of very low viscosity. The fractured and un - fractured implant assembly were examined by using the field - emission scanning electron microscope (FESEM). The heat affected zone (HAZ) susceptibility is quantified by finding the lo wer critical stress (LCS) for a measured hydrogen content. The exact location of the fractures varied according to the type of materials being tested .