Simulation And Experimental Study Of Welding Process Of Small Diameter Pipes With The Addition Of Copper Liner

With the increasing demand for oil and gas resources in the industrial sector,the poor environment in which oil and gas transportation pipelines are located,in order to ensure the safe transportation of oil and gas,there is an urgent need for a reliable method to improve the quality of small diameter pipeline welding problems.Small-diameter pipes can only be welded by single-sided welding double-sided forming method due to the small diameter,welding liner is an important means to ensure that single-sided welding is carried out smoothly.Therefore,in order to obtain high-quality pipe welding joints,this paper studies the introduction of copper liner into the small-diameter pipe welding process,through a combination of numerical simulation and test to obtain reasonable welding parameters,analysis of the addition of copper liner on the small-diameter pipe welding quality improvement effect,the copper liner in the small-diameter pipe welding process to provide some theoretical guidance for the promotion of the application.This paper uses ANSYS software to add no copper liner,add copper liner DN50 pipe welding temperature field,stress field simulation.On the basis of thermodynamic theory,the choice of Gaussian heat source and the combination of raw and dead units to simulate the heat source movement process.Simulation results show that:(1)For the pipe without the addition of copper liner,when the current is 70 A,the voltage is 23 V to meet the welding requirements;for the addition of copper liner for the pipe,when the current is 100 A,the voltage is 23 V to meet the welding requirements;(2)Without the addition of copper liner on the basis of the welding current,the welding current value increased by 43% to meet the technical requirements of single-sided welding of the pipeline with the addition of copper liner;(3)Without the addition of copper liner pipe weld equivalent force on the inner surface of the maximum value of 116 MPa,weld equivalent force on the outer surface of the maximum value of 221 MPa,the addition of copper liner weld equivalent force on the inner surface of the maximum value can be reduced by 7.7%,the maximum equivalent force on the outer surface of the weld can be reduced by 6.3%.In the pipe welding process,the addition of copper liner can significantly reduce the pipe equivalent force.DN50 pipeline welding test results show that: compared with the pipeline without the addition of copper liner,the addition of copper liner pipe wall is smoother and flatter;heataffected zone,the weld area grain is finer and more uniform;when the current is 100 A pipeline average tensile strength increased by 14%,the smallest difference in hardness between different areas of the pipeline,the hardness distribution is more uniform,and the welded joint is more resistant to damage in local locations.Through a combination of simulation and testing,determine the best welding process parameters for the addition of copper liner DN50 pipe current 100 A,voltage 23 V.