Surface breaking cracks in resistance spot welds ofdual-phase steels with electro and hot dip zinc coating
2013 (English)In: Science and technology of welding and joining, ISSN 1362-1718, Vol. 18, no 1, 25-31 p.Article in journal (Refereed) Published
In normal production of resistance spot welded galvanised structures, it is difficult to completely avoid surface breaking cracks. Known key factors to cause cracking are zinc coating, electrode wear during subsequent welding and insufficient electrode cooling. In this report, an embrittlement mechanism was investigated that could be coupled to the galvanisation method for dual phase steels. With identical bulk material and weld parameters, the first 50 spot welds were crack free with electrogalvanised coating, while only 10 out of 50 were crack free with hot dip galvanised coating. Energy dispersive X-ray spectroscopy analysis of the worn electrode surfaces used for welding of the hot dip galvanised coating revealed areas of aluminium oxide. Since aluminium oxide is a very strong isolator, the electrical resistance will increase, which in turn is suggested to increase the surface temperature of the spot weld and thereby increase the probability for liquid metal embrittlement and surface cracks.
Place, publisher, year, edition, pages
2013. Vol. 18, no 1, 25-31 p.
Resistance spot welding, Liquid metal embrittlement, Surface cracking, Advanced high strength steel
Engineering and Technology
Research subject SRA - Production
IdentifiersURN: urn:nbn:se:kth:diva-105376DOI: 10.1179/1362171812Y.0000000068ISI: 000312215500004ScopusID: 2-s2.0-84871349725OAI: oai:DiVA.org:kth-105376DiVA: diva2:570652
FunderXPRES - Initiative for excellence in production research
QC 201302202012-11-202012-11-202015-05-26Bibliographically approved