Relationships between microstructures and properties of buffer layer with Inconel 52M clad on AISI 316L stainless steel by GTAW processing

This study employed gas tungsten arc welding (GTAW) to clad an AISI 316L stainless steel surface with a buffer layer of KMS 309L stainless steel and three subsequent layers of Inconel 52M cladding. Our objective was to identify the optimal cladding parameters required to produce high-quality weldments and investigate the properties of the cladding layers. This study then used these cladding specimens to examine the effects of variation in the dilution rates of several elements on the microstructure and properties of the AISI 316L stainless steel. Our results demonstrate that repeated thermal cycles reduced the hardness of the cladding layer to less than that of the KMS 309L buffer layer and the AISI 316L stainless steel base. This was due to a decrease in overall hardness as the number of cladding layers was increased, resulting from microstructural changes in the AISI 316L stainless steel. Observations of microstructure revealed that increasing the number of cladding layers led to the formation of various solidification morphologies. The primary reason for these changes was an alteration in the composition of the stainless steel (dilution effect) produced by variations in thermal efficiency resulting from the overlapping of layers in the welded cladding. Hot cracking susceptibility tests demonstrate that AISI 316L stainless steel clad with a KMS 309L buffer layer significantly reduced susceptibility to hot cracking through the formation of delta-ferrite precipitates at the interface between the KMS 309L buffer layer and Inconel 52M. As a result, AISI 316L stainless steel clad with a KMS 309L buffer layer showed a significant reduction in susceptibility to hot cracking. (C) 2013 Elsevier B.V. All rights reserved.