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Effects of PWHT on the Microstructure and Mechanical Properties of GTAW-Welded IS2062E350C Pressure Vessel Steel
Alok Vardhan a and Gajesh Kumar a
aAssistant Professor, Department of Mechanical Engineering, Ajay Kumar Garg Engineering College Ghaziabad, India.
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Abstract:
This study investigates the effects of post-weld heat treatment (PWHT) on the microstructural and mechanical properties of IS2062E350C mild steel welded using the gas tungsten arc welding (GTAW) process for pressure vessel applications. Welded joints were fabricated using ER70S6 filler wire, followed by PWHT at 600 °C for one hour. Comparative analysis was performed between as-welded and PWHT-treated samples through tensile testing, Charpy impact testing, Vickers microhardness measurement, and detailed macro- and microstructural characterization. The PWHT samples exhibited significantly improved impact toughness (42.5 J vs. 33 J), reduced microhardness in the heat-affected and weld zones, and refined grain structures, contributing to enhanced ductility and reduced brittleness. Although a marginal decrease in tensile strength was observed post-PWHT (498 MPa vs. 535 MPa), the joints remained structurally sound, with fracture occurring outside the weld zone. ImageJ-based quantitative analysis confirmed grain size refinement and increased ferrite phase fraction in PWHT-treated joints. These findings validate the role of PWHT in enhancing weld performance and reliability for pressure vessels, offering practical guidance for optimizing welding and heat treatment parameters in safety-critical applications.
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Keywords: IS2062E350C mild Steel, Post-weld heat treatment (PWHT), Gas tungsten arc welding (GTAW), Tensile test, Microhardness test, Impact test, Macrostructure, and microstructure analysis.
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©
2026
CSME , ISSN 0257-9731
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