1996 Volume 14 Issue 1 Pages 55-62
With the aid of ultrasonic vibration, brazing of SUS304 austenitic stainless steel using flux and silver-based filler metal was carried out, and the effect of the ultrasonic vibration on the tensile strength and the solidified structure of the joints was investigated. The following results were obtained in this study.
The ultrasonic vibration applied during isothermal holding and during cooling from the brazing temperature of 700°C is significantly effective to increase the tensile strength of the. brazed joints, independent of the joint clearance and applying time of the ultrasonic vibration.
Grain refinement of the solidified structure is achieved by the ultrasonic vibration, followed by increasing in the strength of the brazed joint with the joint clearance of 0.4 mm.
The ultrasonic vibration accelerates the crystallization of Cu rich solid-solution and makes the Cu content decrease in the eutectic matrix of the brazed layer. As a result, the eutectic matrix is more easily strengthened by the tin which tends to form a solid solution with copper, followed by increasing in the strength of the brazed joint.