[MW:6384] Copper Contamination Cracking in Austenitic Stainless Steel Welds

Welding of austenitic stainless steel with cupro-nickel wire resulted in cracking, which was not detected by radiography, but subsequently leaked during pressure testing

 

Newly installed austenitic stainless steel piping joints leaked at girth welds during a precommissioning hydrotest and low-pressure air leak test. The piping was ASTM A312 Grade TP316L seamless pipes and was part of a natural gas liquids

(NGL) recovery project. The failed joints were intended for hydrocarbon gas, diglycolamine (DGA) or instrument air service. Some of the failed joints were subjected to radiographic testing in the field and accepted prior to pressure testing as

part of the code and company standard requirement. Failure analysis of the welds and the subsequent inspection plan to inspect thousands of suspected welds in the project are discussed.

 

BY SANYASI RAO AND ALI Y. AL-KAWAIE