Hi CHAKRA Failures related with new P-22 fittings are not uncommon. These failures are normally due to lack of PMI (positive material identification) and NDT. You should have to be sure that your original material was really the one, which is described on your mill certificates and is free from defects. Another possible cause for the failure was the delivery of your piece with an incorrect fabric heat treatment condition. At last the welding procedure in what it concerns filler metals, pre heating and post weld heat treatment, cooling rate and so on. From your description about the crack it seems that your piece is tempered and during welding process it becomes brittle. Do you check the harnesses of your elbow let? Are they Ok? You should also investigate the configuration design of your arrangement you are welding 50mm thK with 9mm thk, is that right? Regards Luis Marques

Thanks for your replies. Your ideas are in line with my original thought about the problem. Our inhouse checking has indicated that the materials are confirming to F 22. However, some of the forgings from the same batch have higher hardness (280-290 HV). The forging are being checked by WFMPI / UT etc. to rule out any pre-existing cracks. A back ground check indicated that the baking oven for the electrodes was malfunctioning for few days when these welding were carried out. Also the recommended steps like no time delay between welding and SR for high thickness pieces might have flouted in some of the pieces, creating enough scope for HACC (hydrogen assisted cold cracking). Regards