TP304/Q235 Stainless Clad Steel Plates Welding Process And Performance Study

Duplex stainless steel composite plates, by virtue of its excellent anti-corrosion properties and good mechanical behavior, are widely used in many industries fields such as petrochemical and ocean engineering and so on. The great difference of physical and chemical properties between the cladding plate and the base plate is prone to result in the dilution to cladding plate and cracks,which affected the service performance of welded joint. Generally, a transition layer is adopted between the base plate and the cladding plate to obtain the weld joint with excellent properties. The high efficient submerged arc welding process was conducted on the substrate layer, and the SMAW on the composite layer, respectively. But cladding plate and transition layer welding is the key that effects to deal with welded joint. For this, sign a search, it welds craft while to carry on analyze to the craft and the performance.The properties of duplex stainless steel composite plates(TP304/Q235)were studied under the process of different weld sequence. Results showed that the tensile strength of the joints by first welding base plate are better than that of the joint by first welding cladding plate,while the bending test are also better than that of the joint by first welding cladding plate.At the DSS-WM interface,according to the scanning results,although the content of Cr decreased near the fusion zone,it still exceeds the limit content(12.5 % Cr)matching corrosion resistance.At the CS-WM interface, Microstructure hardnesses reach to 400 HV by first welding base plate,and Microstructure hardnesses reach to 440 HV by first welding cladding plate, scanning results show that the variation in Cr,Ni contents which decrease gradually and present evident gradient variation near the fusion zone.Besides that the microstructure shows the existence of carbon element migration near the dissimilar fusion zone.In the Transition layer, Microstructure hardnesses reach to 430 HV by first welding base plate,butαcontent controlled under the required range from10%～14%. Microstructure hardnesses reach to 470 HV by first welding cladding plate,αcontent is only 3%～5% in Transition layer weld metal. Close to the base plate side weld metal of obviously see in the crystal have the carbide precipitation the phenomemon in the organization, crystal inside organize for martensite.