• P-ISSN 0974-6846 E-ISSN 0974-5645

Indian Journal of Science and Technology


Indian Journal of Science and Technology

Year: 2016, Volume: 9, Issue: 39, Pages: 1-6

Original Article

Comparative Evaluation of Impact Strength of Dissimilar Metal Weld between T91 and 304SS Prepared by SMAW and GTAW Techniques


Objectives: The main objective was to evaluate the better joint between dissimilar metals T91 (ferritic) and 304SS (austenitic) prepared by SMAW and GTAW in accordance to their impact strength. Methods/Statistical Analysis: Welding joints between T91 and 304SS were developed using two welding consumables 308L and 309L by SMAW and GTAW respectively. 4 plates of dimension 175mm x 100mm x 6mm were used for welding each of 304SS and T91. Total 9 specimens were prepared according to ASTM A370 standards (55mmX10mmX6mm) for Charpy impact testing, three each from weld bead, HAZ 304SS and HAZ T91 each from SMAW and GTAW welded plates. Findings: Impact strength testing was done with help of Charpy V-notch toughness machine. The standard specimens for Charpy impact testing was placed in the machine and values of impact strength were recorded one after another. As per results, the average impact strength of the weldment prepared by GTAW technique is marginally more as compared to SMAW technique for all sections. The impact strength of the GTAW specimen increases from 304SS HAZ to T91 HAZ passing through the weld metal. The best impact strength is obtained at T91 HAZ of GTAW joint which is 232.67 joules. This increased value of impact strength may be due to movement of carbon particles and formation of carbides and intermetallic. The enhancement in the impact strength is encountered due to increase in micro-hardness which is also published by various authors in the characterization of the weldments. The average impact strength of the weldment prepared by GTAW technique is more as compared to SMAW technique. The dissimilar metal joint prepared by GTAW technique is better joint in accordance to its impact strength. Improvement/Applications: Dissimilar metal joints between austenitic stainless steel and ferritic stainless steel are widely used in various fields like nuclear power plants, steam generators of power plants etc.
Keywords: Dissimilar Metal Welding, Gas Tungsten Arc Welding (GTAW), Impact Toughness Comparison, Shielded Metal Arc Welding (SMAW)


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