Abstract: When some solid metals or alloys are to directly contact with specific liquid metals or alloys in tensile stress, their strength and ductility will drop and early fracture will occur, such a phenomenon is known as liquid metal embrittlement (LME). Iron can be embrittled by liquid zinc. After carrying out resistance spot welding experiment on the galvanized high strength Q&P980 steel plates, cracks were detected on the surface of joint, those cracks were found to be filled with zinc, thus it could be assumed that the cracks were caused by LME phenomenon, as zinc coating was melted and stress existed during welding process. LME cracks mainly distribute on the step and periphery of the indentation, and they showed different depth and forms.

Key words: galvanized Q&P980 steel; resistance spot welding; liquid metal embrittlement (LME); morphology and distribution of crack