Microstructures and properties of single-pass laser-arc hybrid welded stainless clad steel plate

The effects of wire Cr content on the microstructures and properties of single-pass laser-arc hybrid welded stainless clad steel plate (SCSP) were studied. Increasing Cr content strengthened the weld corrosion resistance, but it increased the average grain size of fusion zone (FZ), deteriorated the weld microstructure uniformity, and weakened the weld mechanical property. The variations of the weld properties were closely related to the microstructure changes. The solidification mode and microstructure transformation mechanism of the SCSP hybrid weld were clarified based on the quantitative calculation of the Cr and Ni equivalent contents (Cr-eq and Ni-eq) after the mixing of the wire and base metal. The calculated ratio of the Cr-eq and Ni-eq (theta) could effectively predict the solidification mode and microstructure of the SCSP weld, and then indicate its properties. The skeletal and acicular ferrites formed in the FZ when the theta was larger than 1.35, which benefited to strengthen the SCSP weld.