Study On The Numerical Simulation And Bonding Mechanism In Cold Pressure Welding Of Different Metal

Using of Finite Element Method, numerical simulation of cold pressure welding processes was done. Three kinds of nonlinearities: material nonlinearity, geometric nonlinearity and contact nonlinearity in metal's plastic formation were introduced. Finite element model to joint identical and dissimilar metals by cold pressure welding was founded. On base of analysis to simulation result, it was point out the main cause making dissimilar metal's bonding so difficult was metal's inharmonic plastic deformation. The distribution and changement of stress and strain on interface and in workpieces were analyzed.Making use of experiment and simulation result, main factors that influence welding property of cold pressure welding were discussed. The law how these factors influence the joint's property was pointed out. A formula about the relationship between extrusion times and contamination remainder was founded. Main reason to bimetal's inharmonic deformation was the difference of their mechanical property. Thereby, the empirical formula showing the relation between metal combination's mechanical property and quality of joint was constructed. Integrated influence of extrusion times and metal's mechanical property to quality of cold pressure welding joint was discussed.Taking advantage of advanced SEM and TEM technology and modern TFD theory, explanation to microscope bonding mechanism of cold pressure welding was made. It was pointed out that under the cold pressure welding conditions, the forming of big amount of new phase was impossible. What making bimetal's bonding in cold pressure welding was: with the effect of large plastic deformation and huge pressure stress, the crystal grains on interface were refined seriously and the thin grains were brought so near as atomic scale that transference and redistribution was set in, as a result metallic bonding was founded on interface.