Failure analysis of ferritic stainless steel locking ring

A locking ring made of Ferritic stainless steel, fitted in a pressure gauge, failed after the service of seven years. The mode of failure was analyzed by using Scanning Electron Microscope and optical microscope. A finite element model proposed in this work demonstrated the stress distribution in different regions of the locking ring. It was observed that the ring failed in the same region where the maximum stresses were predicted. Furthermore, a detailed study on the mode of failure found that the failure occurred in stress corrosion cracking conditions.