| Stainless steel clad plate is a kind of plate that carbon steel material is recognized as basement layer and stainless steel material is the composite. Carbon steel has an ability that carry load and stainless steel posses a function, that is corrosion resistant, Compared with stainless steel, stainless steel clad plate not only save a lot of rare and precious metals, also can reduce the cost by 30%-50%, which make it the best alternative to pure stainless steel plate. At present, the welding technology of the stainless steel clad plates with thickness greater than lmm is basic mature, but the ultra-thin stainless steel clad plates with cladding thickness less than 0.5mm, especially the welding of double-sides ultra-thin stainless steel clad plates still exists more problems. The corrosion resistance of welded joint is low, which restrict the extensive application of the stainless steel clad plates seriously.In this paper, laser weldability of the double-sided ultra-thin stainless steel clad plates with the thickness of 0.1 mm stainless steel+0.8 mm carbon steel+0.1 mm stainless steel are researched using 500W pulsed Nd:YAG solid state laser. Three methods are adopted, preset high Cr,Ni stainless steel powder (PSP), weld surface cladding stainless steel powder (CSP), preset 310S stainless steel sheet (PSS) respectively. Moreover, the design and preparation of filling materials, choice of welding methods, the technology and process of laser welding are introduced in detail. The microstructure, corrosion resistance and mechanical properties are analyzed in optimized technological parameter. The results of microstructure show that the weld is very narrow, width is uniformity, crack defects are not found. Double-sided ultra-thin stainless steel clad plates have no deformation basically, and forming performance of laser welding is good. The connection of weld metal with cladding stainless steel and base carbon steel are fine. The laser weld grains of PSP,CSP and PSS methods are smaller than the base metal, grain growth direction is perpendicular to the fusion line, and heat affected zone is almost invisible. Weld center is equiaxial crystal, whereas other area is tiny columnar crystal, and grain orientation is not rule.Intergranular corrosion results show that the bend specimens of PSP method fracture in the weld, which is the most serious in three methods. Due to the crack appeared in bend specimens of CSP method, intergranular corrosion is unqualified. Whereas there is no crack on weld surface of using PSS method, so the weld is qualified. Intergranular corrosion resistant order:PSS method>CSP method>PSP method.Electrochemical corrosion results show that the corrosion potential Ecorr of cladding of base metal, the weld of PSP method, CSP method and PSS method is -0.322V,-0.422V,-0.365V and -0.319V, corrosion current icorr is 7.779×10-7A·cm-2,14.66×10-7A·cm-2,10.47×10-7A·m-2 and 7.962×10-7A·cm-2. The order of the corrosion potential Ecorr is:PSS method>the cladding of base metal>CSP method>PSP method, whereas the corrosion current icorr is:the cladding of base metalPSS method>CSP method. The microhardness of weld of basement layer is 439.0～469.0HV0.1,380.0～400.0HV0.1 and 324.0-383.0HV0.1, and the order is PSP method>CSP method>PSS method>the basement layer.Tensile tests show that the tensile strength of the welded joint using PSP method, CSP method and PSS method up to 81.2%,97.2% and 90.9% of the base metal respectively, elongation reached 21.6%,40.8% and 29.2% of the base metal.Defect analysis shows that the double-sided ultra-thin stainless steel clad plates laser welding joint mainly exist defects such as pore, cracks and organization embrittlement of weld.
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