Finite element simulation on crack repair of high pressure manifold elbow by pulse current

In order to explore the repair trend of tiny cracks generated after elbow forming by hot working with pulse current, the distribution of tiny cracks generated during elbow forming by hot working was studied, and the mechanism of crack repair by pulse current was explored using the method of electro-thermal-structural coupling. Besides, the effect of pulse current on crack repair under different voltages and crack angles was also studied. As shown in the results, the current gathers at the crack tip due to the bypass current at the crack notch, which generates high temperature and thermal compressive stress for the healing trend of cracks. In addition, the repair trend of elbow is affected by the voltage. When the voltage is less than 65 V, the higher the voltage, the greater the temperature and residual compressive stress at the crack tip, and the better the healing effect of crack. The healing effect of crack by pulse current becomes more obvious at the increasing crack angle. Specifically, the healing effect is the weakest for the 0° crack distribution and the most obvious for 90° crack distribution. Generally, the research results lay a theoretical foundation for the application of pulse current repair technology in high pressure elbow, which is of great significance for improving the strength of high pressure elbow and ensuring the safety of oil and gas production.