Characterization of stainless steel inertia welds using HTS SQUID NDE

Inertia welding has become one of the key joining technologies in the aerospace industry with, at present, no reliable and reproducible nondestructive technique to evaluate weld quality. We previously reported on the preliminary studies of solid-state inertia welds in stainless steel using HTS SQUID magnetometers. A comparison of the SQUID data with that obtained from destructive metallurgical analyses of the welds was not conclusive, due mainly to the limited range in perceived weld quality of the sample set investigated. In this paper we report on eddy current-based measurements carried out on a set of stainless steel samples fabricated using parameters designed to create a wider range of weld qualities.