This page contains a brief description of the work and selected graphics. For further information, contact Ivar. This work was published in the Welding Journal, the official publication of the American Welding Society.
Hydrogen assisted cracking in gas metal arc welds was investigated.
Hydrogen uptake was characterized for one set of welding conditions by adding various amounts of either hydrogen gas or moisture to the shielding gas. The hydrogen content of each batch of specimens as measured using the RPI Hot Silicone Oil Method. In this method, the volumetric measure of the diffusible hydrogen content is made by placing the welded specimen in hydrogen saturated silicone oil at 100ºC and collecting the extracted hydrogen in a burette. Because extraction takes place at 100ºC the time required to collect the hydrogen is approximately 1.5 hours vs 72 for the BWRA-IIW method.
The relative susceptibility to hydrogen-assisted cracking was determined with the augmented strain cracking (ASC) test. The known strain is applied to a traverse section of a test specimen containing a controlled amount of hydrogen. Crack initiation and propagation was monitored with acoustic emission equipment.
All-weld-metal specimens cut from four orientations with respect to the welding direction have a susceptibility to hydrogen assisted cracking which is virtually indistinguishable from that of welds on HY-130 base metal specimens.
Test results suggest that with 1.1% augmented strain a hydrogen content of less than 1ppm (1.1cc/g of added filler metal) was required to avoid hydrogen-assisted cracking in either HY-130 or all-weld-metal (AX-140) filler metal specimens.
