| Metal centrifugal casting composite pipe has been widely used in dredging,petroleum,chemical,natural gas and other industries.It is a special metal pipe that has developed rapidly in recent years.Usually,the inner layer of the bimetallic centrifugally cast composite pipe is composed of high-chromium cast iron with high wear resistance and corrosion resistance,and the brittle hardness is large;while the outer layer is composed of stainless steel or low carbon steel with high toughness.Due to the limitation of the preparation process,the length of the single tube of the bimetal composite pipe is limited.In actual use,it is necessary to weld the flange at the end of the composite pipe,and then connect the composite pipe through the flange.However,when the flange is welded at the end of the bimetal centrifugally cast composite pipe by the conventional process,the weld between the flange and the composite pipe will generate a large tensile stress during the solidification and cooling process,so that the outer layer and the inner portion of the composite pipe Separation or even cracks between the layers will reduce the impact resistance of the inner layer of the composite tube high chromium cast iron.Moreover,the welding of the composite pipe and the flange is dissimilar metal welding,and the weld structure is prone to martensite,resulting in unstable weld performance.These problems will greatly shorten the service life of the bimetallic composite pipe.Therefore,according to the structural characteristics of the flange and bimetal composite pipe,the temperature field and stress field in the welding process were simulated by ANSYS finite element analysis software.Firstly,the preheating temperature required during the preheating process before flange welding is obtained by theoretical calculation of the components,and the ANSYS finite element welding simulation experiment is carried out by presetting several sets of different welding process parameters,and the simulation results are compared and compared.analysis.In the simulation experiment,the entity modeling is first established by building the component entity,meshing,defining the material parameters,etc.,and then applying and post-processing the load step.The command flow in this paper is written by parameterization.If you need to modify the parameters to carry out different welding simulations in the study,you only need to change the parameter value of the front part of the command stream,which can be different for different welding process parameters and different preheating temperatures.Simulation.According to the simulation results,the temperature field and stress field distribution of different parameters in the welding process of composite pipe and flange and the distribution of residual stress at each point on the composite layer after welding are obtained.The ANSYS welding simulation results and theoretical experience are used to optimize the welding process parameters in the actual production process,and the preliminary welding process experiments are carried out on the composite pipe flange welding.After the welding,the stress test of the composite layer of the bimetal composite pipe was made,and the metallographic structure analysis and the Vickers hardness test were performed on the welded sample,and finally the weld of better quality was obtained and the weld did not have obvious crack..This study establishes a dynamic simulation analysis method for welding temperature field and stress field,and provides theoretical basis and practical production guidance for optimizing the welding structure process and parameter specifications. |
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