Welding guidelines for duplex, super duplex and hyper duplex stainless steels

摘要

When welding duplex and super-duplex steels, the biggest challenge is to maintain an optimized balance between the austenite- ferrite microstructure in the final weld metal in addition to the desired mechanical properties. The purpose of this paper is to share our knowledge regarding various aspects related to practical fabrication of duplex, super-duplex and hyper duplex stainless steel welding. The paper provides practical advice on how to bring out the best of these complex materials as well as recommendations on how to retain the optimal balance of the microstructure during and after welding, and describes chemical the composition of the grades and the effect that it has on their structural stability at a macro level during welding. Joint design, shielding and backing gas selection, heat input and interpass temperatures are all covered.