1990 Volume 76 Issue 2 Pages 254-261
The composite steel of SUS316L and SM50B made by diffusion and hot roll bonding processes were subjected to the investigations of nature of bonding interface and bonding strengths. The test results obtained are summarized as follows ;
(1) Bonding strength of clad steel increases with increase of bonding temperature and deformation ratio, and reaches the tensile strength of mother steel, when the temperature is over 900°C. And also the bonding strength increases with increase of bonding ratio of the interface. The dependence of bonding ratio becomes larger for KC value, compared with shear or ram tensile strengths.
(2) The bonding strength of clad steel changes, when the clad steel is hold at high temperature. This is caused by the both effects of increased strength of martensite structure and decreased strength of decarbonized layer at bonding zone.
(3) The stable cracks initiate at the defects on bonding interface, propagate accompanied with linkage of each defect and finally lead to debonding of clad steel with small fracture ductility. The behavior of crack initiation is affected by bonding ratio of interface, difference in measuring method of bonding strength and strength of each material composing clad steel.
