Volume 5 - Dissertation Hagen Kerl

Hagen Kerl

TitleA contribution to the increase of electrode cap life in resistance spot welding.
Publication typeDissertation
Pages154 pages
Illustrations97 illustrations
Format21 x 14,8 cm
Price48,80 € / 61,10 SFr
Publication date2018
Published byShaker Publishing Ltd.


The work deals with the stand quantity-reducing factors of electrode caps in resistance spot welding. With the increased use of different material grades in vehicle construction, there are increasing process costs for the joining process. In general terms, each type of sheet coating has a stand quantity-reducing influence. Common sheet metal coatings are zinc or aluminum-silicon coatings. These coatings and the sheet metal material itself react with the electrode cap during welding, requiring more frequent re-milling and replacement of the electrode caps. The wear of an electrode cap is composed of its working surface enlargement and alloy formation with the sheet metal coating. Both increase the contact resistance of the electrode cap with the sheet surface. Suitable alloying concepts of the electrode caps are based on an increased hot hardness and the reduction of the diffusion amount of impurity atoms. The investigations show that no cap material (CuCrZr1, CuAg0.1, Nitrode) is suitable for joining all sheet materials (HX340LAD+Z, 22MnB5+AlSi, AlMg3). Further, an analysis of the influence of various welding parameters is to be carried out, in particular with impulse welding, the discontinuous welding current supply. The interest lies in the change in tool life with variation of the welding parameters. The analysis is carried out on single-cut and multi-cut asymmetric plate combinations. The requirement to detect the weld lens growth non-destructively is realized by measuring the voltage drop between the joining plates. The resistance curve can be used to determine when a weld lens first develops between which sheets.