To provide a joint strength evaluating method by non-destruction instead of a destruction test exclusively used when joint strength in resistance brazing is evaluated.
In this method, when resistance brazing is executed by holding a brazing filler metal 2 between base materials 1a and 1b, pressurizing and electrically heating them, tensile strength is estimated by a linear multiple regression formula wherein a dynamic current characteristic value and tensile strength in a resistance brazing process are respectively expressed as an independent variable and a dependent variable, and an optimal current characteristic value for realizing target tensile strength is decided to execute resistance brazing. This controller is provided with a resistance brazing device 4, a dynamic current monitor part 5 which measures a fluctuation of a dynamic current when resistance brazing is executed, a tensile strength arithmetic part 6 which calculates and estimates tensile strength using the linear multiple regression formula wherein the dynamic current characteristic value and tensile strength are respectively expressed as the independent variable and the dependent variable, an optimal current setting part 7 which decides the optimal current for realizing target tensile strength, and a memory part 8 which stores the optimal current value and calls up the optimal current value corresponding to the base material.
OKUDA TOSHIYUKI
TAKESHITA KUNIMASA
