Study On Bonding Process And Thermal Stress Finite Element Simulation Of Transient Liquid Phase Diffusion Bonding

This paper deals with the theoretical basis,mathematical models as well as research results in domestic of Transient liquid-phase(TLP) diffusion bonding.This study used an open environment of the transient liquid phase diffusion bonding equipment, using argon gas protection, the use of medium frequency induction heating method for diffusion bonding of rapid heating, the main research the high-quality carbon steel 20 pipe transient liquid phase diffusion bonding,and using the finite element numerical simulation software simulation analysis the temperature field and stress field of the bonding process of TLP.Using nickel-based BNi2 as 20 pipe TLP bonding middle layer,based on the establishment orthogonal optimization test table L9 (34) of the three factors (bonding temperature, holding time, the connection pressure) three-level to boinding, the restls showed that the bonding temperature has a significant impact on the performance of TLP bonding joint and the pressure also has an impact on tensile of TLP bonding joint.And through analysis of the mechanical properties, tensile fracture surface scanning as well as the distribution of the interface elements, micro-hardness testing of the TLP bonding joint in the different process parameters,when 20 steel with single temperature process at 1160℃for 3min and using pressure for 4MPa,we can get a good performance TLP bonding joints.Through analysis temperature field simulation results of the finite element of 20 steel pipe transient liquid-phase diffusion bonding, in the cooling process,the temperature will have a sharp decline in the joints at the initial stage of the cooling,and will yield residual stress concentration, thus affecting the TLP bonding joint performance, and with the initial temperature increases, the weld deformation will more serious;By analysis the stress field simulation results of its finite element analysis, in the cooling process,the weld have a larger stress than others,while the stress level of middle layer is lower than the base material on both sides of the weld area,so the residual stress mainly concentrated the base material of vicinity of the middle layer,while the middle layer have the lower residual stress,so the near of middle layer is weak performance of TLP Joints areas, because of the stress of the weld and the base material on both sides of the weld area falling sharply at initial stage of the cooling,The stress concentration will be to alleviate if we can reasonably use the middle layer,and the performance of the TLP bonding joint will increase...