Welding Procedure and Evaluation Test for Oil and Casing Tubing Made of SA516Gr70(R-HIC) Steel

Abstract: SA516Gr70(R-HIC) steel is used to manufacture tubing and casing for oil and gas wells, operating under complex conditions including temperatures from -20 to 250°C, pressures from 20 to 100 MPa, corrosive media such as CO₂, H₂, and H₂S, and various complex stresses. These demanding service conditions impose high requirements on the performance of the welded joints. This study designs a welding procedure using Gas Tungsten Arc Welding (GTAW) for the root pass, followed by Shielded Metal Arc Welding (SMAW) for fill and cap passes, employing ultra-low hydrogen electrodes HS09MnSHG-3 and J507RH. Preheating was applied at 85–90°C, with interpass temperature controlled between 130–150°C, and heat input maintained within 15–20 kJ/cm. Post-weld heat treatment was performed at 590±10°C for 6 hours to relieve residual stresses and remove diffusible hydrogen. The welded joints were evaluated through visual testing (VT), radiographic testing (RT), mechanical property testing, Hydrogen Induced Cracking (HIC) testing, and Sulfide Stress Corrosion Cracking (SSCC) testing. The results demonstrate excellent weld joint quality, exhibiting high strength, good ductility and toughness, as well as strong resistance to hydrogen-induced cracking and stress corrosion cracking. The proposed welding procedure is rational and provides effective guidance for practical production, fully meeting the enterprise's design requirements.