TO DESIGN OF WELDING PROCEDURE TO AVOID DELAYED CRACKING PHENOMENON IN ASTM A335 P22 MATERIAL

摘要

Single side 12mm thick V butt joint was prepared using GTAW and SMAW process on 2.25Cr- 1Mo (P22) low hydrogen filler material 90SB3. A post weld heat treatment (PWHT) was carried out on these welded samples to reduce the induced stresses in weld joints. Weld joints were characterized in terms of change in mechanical properties and microstructure. It was observed that weld joint prepared using GTAW is more ductile than weld joint prepared using SMAW. After PWHT, the ductility of the welded materials is increased regardless of the joining process. It was also observed that SMAW weld joint of P22 material exhibited high hardness compared to GTAW weld joint. Hardness and tensile values obtained were in compliance to the standard requirements to suppress delayed cracking phenomenon. Delayed cracking phenomenon was successfully eliminated by using low hydrogen electrode and by increase in heat input rate during different passes of welding.