Abstract
Influences of chemical compositions of base metal, temperature difference ΔT between liquidus and solidus, and arc time on the susceptibility of liquation cracking were studied using the Varestraint test on 6082 aluminum alloy which was GTA spot welded. A commercial 6082 alloy and seven kinds of experimental 6082 alloy whose magnesium, silicon and manganese contents were changed were used. The susceptibility of liquation cracking was evaluated from the maximum crack length observed in heat affected zone after the Varestraint test. Liquation cracking was observed along grain boudaries on which low melting point compounds (mainly Mg2Si) were melted. The maximum crack length increased with arc time and ΔT. The addition of Si and Mg which increased ΔT promoted the liquation cracking, whereas the Mn addition suppressed the cracking by grain refining.
