| 摘要 |
<p>It is decribed a method for the non-destructive test of a joint obtained by electric spot welding of two sheets, substantially of the same material, joined together in a local zone with the formation of a core, its structure having a thermal diffusivity substantially different from the thermal diffusivity of the material of the two sheets before welding, a result which is obtained only when the welding is of a good quality. …<??>This purpose is attained by a device whose main characteristic is to comprise an electrode able to supply a source of heat and a detector which are fitted to be placed on two conveniently chosen points on the surface of the two welded sheets, a generator feeding the electrode and an amplifier having an input connected to said detector and an output connected by a A/D converter to a computer able to process the signal and to give an indication of the welding quality on the basis of the measured value of the thermal diffusivity.</p> |
