Analysis Of Residual Stress And Microstructure Of Stainless Steel Composite Plate Welded Joints

The 304+Q345R composite board also has 304 stainless steel anti-corrosion and Q345R high-strength properties,and is widely used in the petrochemical industry Welding is the main method of manufacturing such equipment.The welding heat of the substrate Q345R welding affects the microstructure and properties of the austenitic stainless steel of the multiple layer 304,and generates residual stress.Studying the temperature field and residual stress distribution during the welding process of the composite steel plate has a strong theoretical and practical engineering significance for the rational design of the welding process and reducing the welding residual stressThis article takes Q345R,304 and composite steel plate as the research object respectively,tests the thermal cycle curve in the butt welding process,uses the blind hole method to test the residual stress after welding,and uses the ultrasonic aging device to eliminate the welding residual stress,and the elimination effect is good.In this paper,the finite element simulation software ABAQUS was used to develop sequential coupling process of temperature field-stress field.The FORTRAN language was used to realize the loading and moving of the heat source in the welding process The welding process of the three plates was simulated and the welding temperature field and residual stress after welding were analyzed.Field distribution.The numerical simulation of the temperature field is in good agreement with the measured curve.The temperature of the weld zone passing through the heat source rises sharply.When the heat source passes,the temperature gradually decreases with time.The maximum transverse and longitudinal residual stresses in the stress field occur in the weld and in the surrounding area,and the stresses in the base material areas on both sides of the weld tend to be symmetrical.In the process of composite panel simulation,the method of combining the oblique seam with the multi-layer and multichannel welding simplification technology was studied.It was found that the stress distribution gradient of the composite panel was inclined with the weld bead,and there was a stress discontinuous interface between the two materials,Easily lead to fractures and other failures of welded joints.A metallographic experiment was performed on the welded joints of the composite plate to observe the composition of the structure.It was found that the composite effect of the base layer and the composite layer was good.The weld microstructure of the composite layer was composed of austenite and ferrite and the thermal effect of the base layer.The zone consists of overheated zone,phase change crystallization zone,and incomplete crystallization zone and gradually transitions to the parent material zone.The energy spectrum scanning of the multi-layer fusion zone revealed that the chemical composition of the base material and the weld zone are close to each other,which has a positive effect on the overall performance of the welded joint.