The Hydrogen-Induced Cracking Resistance of Consumables for Use in the Fabrication of the COLLINS Class Submarines.
1997
Davidson, James L.
A MIL-121TM flux cored arc welding consumable, Alloy Rods Dualshield(registered) II 120-M2, has recently been qualified for use in the fabrication of the pressure hull of the Royal Australian Navy COLLINS class submarines. Gapped bead on plate testing has been carried out to compare the hydrogen-induced cracking resistance of welds produced using the flux cored arc consumable with welds produced using the manual metal arc and submerged arc consumables currently used on the submarines. These tests will ensure that the introduction of the flux cored arc welding consumable does not increase the risk of hydrogen-induced cracking in the submarine pressure hull. The resistance of the flux cored arc welding consumable was found to be better than either the manual metal arc or the submerged arc consumables and the introduction of the flux cored arc welding consumable for use in the welding of the COLLINS pressure hull does not increase the risk of hydrogen induced cracking. The lower strength level of the deposited flux cored arc weld metal, contributed to its greater hydrogen-induced cracking resistance by reducing the residual stress state in the weld metal and by improving its inherent resistance to hydrogen 'embrittlement'. It is shown that there is no fundamental reason for a 'one to one' relationship between hydrogen-induced cracking resistance and toughness in nominally 690 MPa yield stress weld metal. The hardness of the heat affected zones produced by each of the processes were not significantly different and gave no information regarding the likelihood of weld metal hydrogen induced cracking.
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