Abstract
The mechanical performance of welded ST37 low-carbon steel tube pipe is influenced by the welding process and subsequent heat treatment. This study compared the tensile properties of quenched ST37 tube pipe welded using Shielded Metal Arc Welding (SMAW) with E6013 electrodes and Gas Metal Arc Welding (GMAW) with ER70S-6 filler wire. The specimens were water-quenched and evaluated through tensile testing according to ASTM E8/E8M, visual inspection, fracture observation, and statistical analysis. SMAW exhibited a higher average yield strength than GMAW, at 403.91 MPa and 392.69 MPa, respectively; however, the difference was not statistically significant (p = 0.684). The average ultimate tensile strength was 616.17 MPa for SMAW and 540.79 MPa for GMAW. Mean elongation was 12.85% for SMAW and 6.90% for GMAW, with a statistically significant difference (p = 0.020). The SMAW specimens therefore showed approximately 86.2% higher elongation than the GMAW specimens. All SMAW specimens fractured outside the weld region, whereas one GMAW specimen fractured within the weld region. Overall, SMAW demonstrated greater elongation under the investigated conditions, while differences in yield strength and ultimate tensile strength were not statistically significant.