Material properties characterization of low carbon steel using TBW and PWHT techniques in smooth-contoured and U-shaped geometries

• Effects of post weld heat treatment (PWHT) and temper bead welding (TBW) on properties are tested.
• Charpy V-notch impact and tensile testing was performed on multi-layer welding of low carbon steel.
• At room temperature and below, TBW gave better impact toughness than both PWHT and parent material.
• Above room temperature but below 60 °C, PWHT gave better impact toughness than TBW.
• Above 60 °C, both TBW and PWHT showed impact toughness lower than that of parent material.

This paper investigates the effects of the temper bead welding (TBW) technique and post weld heat treatment (PWHT) on mechanical properties of multi-layer welding on low carbon steel specimens using Charpy V-notch impact testing and tensile testing. Several samples of two different weld geometries, viz. (i) smooth-contoured, and (ii) U-shaped were made with multiple bead layers using both TBW and PWHT techniques. Impact testing showed that at room temperature and below, TBW gave an impact toughness in the Heat Affected Zone (HAZ) better than both PWHT and the parent material. At temperatures higher than the room temperature but below 60 °C, PWHT gave better impact toughness in the HAZ. Above 60 °C, both TBW and PWHT showed impact toughness lower than that of the parent material. In tensile testing, both TBW and PWHT weld metal specimens produced acceptable results; however, TBW gave yield and tensile strengths closer to that of the actual material than PWHT.