Abstract:
This work is an attempt to find the reasons which have lead to cracking of weld seam no. 6 of Ammonia Synthesis Convertor of Tata Chemicals Limited, Babrala, Failure of convertor occurred after six months of service in hydrogen atmosphere.
Microstructure of the weld metal showed some amount of abnormalities in the region where cracks were observed. Coarse carbides and coarse prior austentic grains were observed, in the weld metal. Hardness of the weld metal was found exceeding the safe limits of 250 HV, in the region where cracks were observed. These abnormalities were found to be due to incorrect post weld heat treatment, which have resulted in hydrogen induced cracking (HIC).
