Abstract
Nondestructive testing of diffusion welded structures must be accomplished in a reliable manner, before diffusion welding can be considered as a production process. This study was achieved to investigate the characteristic of ultrasonic testing as a means of nondestructive testing of diffusion welded SUS 304 stainless steel.
The following results were obtained.
1) Information regarding the joint efficiency is extracted from reflectivity (the relative amplitude of reflection from the joint and bottom echo of a reference block), when roughness of welded surface is controlled constantly.
2) The relation between reflectivity and joint efficiency is influenced by roughness of welded surface that determines size, shape and distribution of voids, and not by other welding conditions such as time, temperature and pressure.
3) Reflection efficiency is closely related to the width of void at interface. The smaller the width of void is than 1/5 of wave length, the smaller reflection efficiency is.
