Numerical Simulation Of Effect Of Cladding Thickness On Residual Stress And Deformation Of Welded Joints Of 304/Q355 Composite Plate

Stainless steel composite plate with corrosion resistance,high strength and high cost performance is widely used in the field of equipment manufacturing.However,the weld metal is composed of base weld,cladding weld and transition weld,and the chemical composition and thermal physical properties of the three layers of weld metal are different,which is easy to produce welding stress and strain.The thickness of composite plate is related to weld composition,welding stress and strain.Therefore,it is of great engineering practical significance to study the influence of the thickness of the cladding on the stress and strain of the welded joint of the composite plate.In this paper,multi-pass welding process experiments were carried out on304/Q355 composite plates with cladding thickness of 0.3 mm,1 mm,and 2 mm(base layer thickness is 13 mm).The residual stress on the welded joint of composite plates with cladding thickness of 2mm was measured by X-ray diffraction method and compared with the corresponding simulated value.The welding numerical models of 304/Q355 composite plates with thickness of 0.3mm,1 mm and 2 mm were established,and the temperature field of the composite plate welding was simulated by numerical simulation technology.The temperature load was applied to the transient structure by indirect coupling loading method.The stress and strain fields of the welded joints of composite panels with different cladding thicknesses were numerically simulated,and the effects of different cladding thicknesses on the stress and strain fields of the welded joints were analyzed and compared.In addition,the effect of adding constraints on the stress and strain field of the welded joint of the composite plate was studied,and the stress value and deformation under unconstrained conditions were compared.The results show that the stress distribution of vertical and parallel welds increases with the increase of cladding thickness under different cladding thickness.The maximum residual stress of stainless steel composite plate occurs in the welding heat affected zone or weld center.Due to the limitation of the yield strength of the material,the maximum stress value appears near the yield strength of the material.In addition,the deformation after welding increases with the increase of the thickness of the cladding layer,and the direction of the largest deformation is the direction of the thickness of the weld.Under different constraints,side constraints can improve the deformation after welding.The deformation of 2 mm stainless steel composite plate under free constraints is 6.9mm,while the deformation under side constraints is 1.63 mm,but the residual stress of side constraints is also greater than that under free constraints.Through the surface stress test of the composite plate,the test results are basically consistent with the numerical simulation stress value change trend,and the results show a good similarity.It provides a theoretical basis for the welding process of this kind of composite plate.