Microstructural characterization of dissimilar weld joint between ferritic steel and stainless steel

Abstract

In this investigation, microstructural variation across the dissimilar weld joint between modified 9Cr-1Mo ferritic steel and 316LN stainless steel with nickel-based filler metal was fabricated and characterized by various techniques. It was observed that the heterogeneous microstructure and non-uniform microhardness were developed across the dissimilar weld joint. Carbon-depleted soft zone, carbon-enriched hard zone, type I and type II boundaries are evident at the P91 heat-affected zone (HAZ) – buttering layer interface. An unmixed zone was observed at the weld metal-316 LN stainless steel HAZ interface. Distinct microstructures were developed across the dissimilar weld joint are due to the mismatch in chemical composition, crystal structure and melting temperature difference between base metals and filler metal.

KEYWORDS:

• Dissimilar weld joint
• buttering layer
• ferritic steel
• stainless steel
• microstructures

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The authors are thankful to UGC-DAE Consortium for Scientific Research, University Grants Commission (UGC-DAE CSR) for providing financial assistance (Project No. CSR- KN/CRS-56/2013-14/655) to carry out this investigation.