Electromagnetic Heat Intensification Technology Of Pipe Weldment

In the welding process,holes,cracks,and other defects were inevitable.The presence of these defects will greatly reduce the service life of the welded parts.Especially in the field of pipeline welding,the presence of these defects will not only affect the performance of the welded parts,but also cause major safety accidents in real life.This article takes the 316 L stainless steel pipe widely used in petroleum transportation and nuclear facilities as the research object,aiming at the ubiquitous hole defects in welding,combined with theoretical analysis,experiments and numerical simulation methods to perform electromagnetic heat cracking strengthening on welded joints,the main content includes the following aspects:Firstly,with the aid of the Cauchy integral transformation and the planar potential function of fluid mechanics,the theoretical analysis model of metal components with void defects was established.The complex potential function in the electric field was constructed with the basic knowledge of electric field,and the metal components with void defects in space were deduced.The instantaneous heat source power,current density,and temperature field distribution formula for the pulse discharge are used to analyze the temperature change at a certain point near the hole during the pulse discharge and plot the change curve.Then,the ZL-2 super-pulse discharge device was used to complete the electromagnetic heat cracking test on the 316 L stainless steel welded parts with void defects.By comparing and analyzing the tensile properties,fracture scanning,microhardness,microstructure,and surface residual stress of the specimen before and after discharge,the macroscopic and microscopic perspectives of the 316 L stainless steel pipe welded joint with hole defects were studied.Strengthen the effect and mechanism of action.The finite element model of 316 L stainless steel specimen was established by ANSYS finite element analysis.The temperature and stress fields in the welding process were simulated using the method of birth and death.The thermal-electric coupling and thermal-structure coupling were used to establish a finite element analysis model of the spatial hole defects,and the current density,temperature field and stress field near the hole during electromagnetic heat crack arrest were solved.The results of numerical simulation and theoretical analysis and experimental results confirm each other.This paper validated the effectiveness of electromagnetic thermal cracking on metal components containing voids and defects in the three aspects of theoretical analysis,numerical simulation and experimental research,and lays a foundation for the application of electromagnetic thermal crack arrest technology.