Numerical Analysis Of Metal Flow In High Frequency Resistance Welded Pipe During Welding Extrusion

With the increasing importance of the exploration and development of marine oil and gas resources,the demand for deep-sea thick-walled oil well pipes and transport pipes has become increasingly urgent.At present,most welded pipe mills rely on experienced operators to select and adjust welding process parameters by observing the appearance of the weld burr.The influence laws of weld burr morphology,welding quality and welding process parameters have not yet been mastered,so it is difficult to guarantee high-end welded pipe products.The welding process of high frequency resistance welded pipe is a very complicated process involving electromagnetic field,temperature field,stress field and speed field.Based on ANSYS,DEFORM,and FLUENT finite element software,numerical simulations were performed on the welding process of high-frequency resistance welded pipe.The research involved includes:(1)Aimed at the whole high-frequency resistance welding process,the idea of subsection simulation of the weld burr forming process was put forward.ANSYS was used to establish the electro-magnetic-thermal coupling finite element model of high frequency resistance heating process.The temperature field of the welding point area was obtained.The temperature field was divided into two areas.The rigid-plastic model of the deformed metal extrusion process was established in the solid area in DEFORM,and the stress field and velocity field of the deformed metal flow process were analyzed,obtains the appearance of deformed metal burrs on the inner and outer surfaces of the welded pipe,and deeply studies the differences between the inner and outer surface deformed metal burrs.(2)For molten areas,based on the deformed metal burr,a two-phase flow model for metal flow in the molten metal extrusion process was established in FLUENT.The velocity field of the molten metal flow process was analyzed,and the external surface molten metal burr shape was analyzed.The changes in appearance over time were analyzed.(3)The metal flow angle was introduced as the evaluation standard of welding quality,and the main process parameters of high frequency resistance welded pipe were analyzed,such as the amount of extrusion,welding speed,current size,current frequency and electrode position,etc.The rule of influence between the line angles reveals the appearance of the weld burr under special conditions such as electrode asymmetry,misalignment,and the shape of the bonding surface.(4)The corresponding sample was taken from the factory to observe the metal flow line angle through metallographic experiments.The tensile strength test verified the connection between the weld strength and the metal flow line angle,and finally measured the shape of the weld burr on the outer surface of the weld pipe test piece.The appearance and metal flow angle verify the accuracy of the numerical simulation.