Reheat cracking susceptibility and toughness of 2% CrMoWVNb P23 steel welds

This article is concerned with weldability of P23 pipe steel, with emphasis on reheat cracking sensitivity and toughness of simulated HAZs and thick-section multipass welds. The results demonstrate that the weld metal made using the B323 filler metal closely matching to P23 steel is far more critical than the parent steel HAZ. In the as-welded condition, the B323 weld metal exhibited excessive hardness of ≈ 380 HV and only diminutive Charpy toughness of ≈ 7 J at + 20 °C. Adoption of PWHT (760 °C /2 h) enhanced the weldment toughness; however, it also inevitably raises risk to reheat cracking in the weld metal that showed reduction of area (RA) no more than 2–3% in the BWI cracking test. The results show that thick-section multipass welds made using filler metal with the chemical composition closer to P24 grade material are less susceptible to reheat cracking than matching P23 grade welds.