Patent ID: 8222896
Filing Date: 2012-07-17
Classification: G01N

Abstract:
1. A method of analyzing a weld strength of a friction stir spot weld, the method comprising: on a friction stir spot welded workpiece having a first side comprising a visible friction stir spot weld hole and an opposing second side comprising a substantially smooth surface in the vicinity of the spot weld hole, passing an eddy current probe over the spot weld hole from the second side, and producing therefrom an eddy current signal representative of a material thickness of the workpiece; analyzing the eddy current via an eddy current analyzer and monitoring on a display a graphic representation of the analyzed eddy current signal as the probe passes over the spot weld hole, and identifying a local minima of the graphic representation defined by a displayed characteristic J-shaped curve, the local minima defining a remaining material thickness of the workpiece at the bottom of the spot weld hole; from a defined correlation between the graphic representation and the remaining material thickness, determining from the graphic representation a value of the remaining material thickness; and from a defined correlation between weld strength and the remaining material thickness, determining a weld strength of the spot weld as a function of the remaining material thickness.