CHARACTERISTICS OF BONDING INTERFACE AND STRENGTH OF HOT ROLLED STAINLESS CLAD STEEL

A composite of SUS 316L and SM50B made by diffusion and hot roll bonding was subjected to investigations of the bonding interface and bonding strength. Bonding strength increases with increase of bonding temperature and deformation ratio, and reaches the tensile strength of the parent steel when the temperature is over 900°C. Bonding strength increases with increase of bonding ratio of the interface. The bonding strength changes when the clad steel is held at high temperature. This is caused by the effects of increased strength of martensite structure and decreased strength of decarbonized layer at the bonding zone. Stable cracks initiate at defects on the bonding interface, propagate accompanied with linkage of each defect and lead to debonding of clad steel with small fracture ductility.