Effect of Parameters on Spot Formation in Resistance Welding of Structural Steels.

In a previous study concerning the resistance spot welding of steel plates, an attempt was made to control the welding process nondestructively by thermal expansion. This attempt has demonstrated that for materials with very similar chemical compositions, the nugget size and the expansion behavior could vary significantly. In order to clarify the observed differences, pulsation welding tests were carried out which now make it possible to make hypotheses concerning the effect of the following factors: the material's electrical resistivity; the material's thermal conductivity; and the characteristics of the contact surface. Specific tests make it possible to assess the effects of the aforementioned factors on the spot weld formation.