Investigation of the Effects of SMAW and GTAW Welding Processes on Iron Dilution in Inconel ۶۲۵ Cladding on ASME SA۳۸۷ Low-Alloy Steel

This study investigates and compares the effects of Shielded Metal Arc Welding (SMAW) and Gas Tungsten Arc Welding (GTAW) processes on the iron dilution during cladding of the nickel-based superalloy Inconel ۶۲۵ deposited on ASME SA۳۸۷ Gr.۱۱ low-alloy creep-resistant steel, which is widely used in pressure vessels. The main challenge is achieving an optimal balance between metallurgical quality (dilution percentage) and processing time. In the GTAW process, cladding was performed in two-layer and three-layer configurations, whereas in the SMAW process, three layers were applied. The extent of iron (Fe) migration and elemental distribution at the interface were evaluated using EDS analysis, and precise time measurements were conducted for each welding pass. Chemical analysis results indicated that in the SMAW process, the iron dilution reached ۳.۸% after applying three layers. In contrast, in the GTAW process, iron dilution values of ۴.۳% for two layers and ۲.۲% for three layers were measured. This behavior is attributed to differences in heat input, thermal concentration, and the superior control of substrate surface melting in the GTAW process. The reduction in dilution observed in the three-layer GTAW configuration compared to the two-layer configuration is mainly due to the increased contribution of filler material in the final weld metal layer. On the other hand, the SMAW process exhibited a significantly higher deposition speed compared to GTAW, achieving a productivity index of ۲.۷۵, whereas the corresponding value for GTAW was ۰.۸۳. The productivity analysis demonstrated that although GTAW provides better dilution control in each layer, SMAW is considerably more efficient for industrial applications, particularly in large-scale projects. Despite the need for an additional layer, SMAW proves to be more suitable for industrial cladding applications.

کلیدواژه ها:

cladding ، Dilution ، Inconel ۶۲۵ ، Productivity Index