TWI Industrial Member Report Summary 163/1981
By M H Scott and M F Gittos
Tensile, Charpy and CTOD tests were used to evaluate the mechanical properties of two-pass MIG welds in 13mm plates of the Al-4.5%Mg-0.8%Mn alloy 5083 and the Al-1%Si-0.8%Mg-0.7%Mn alloy 6082. For 5083, Al-5.2Mg-0.8%Mn alloy (5556A) was used as the filler metal, for 6082, the same filler metal or Al-5%Si alloy (4043A). Welded 5083 was tested in the as-welded condition, while for welded 6082, the effects of postweld heat treatment were also investigated. Tensile and CCT tests were used to evaluate the mechanical properties of single-pass TIG welds in 3mm 6082 sheet, welded with 5556A or 4043A filler metals. The tests were carried out in the as-welded condition and after postweld heat treatment.
The strength and toughness properties of welded 5083 compared favourably with those of parent metal. Welds in 6082 had poorer properties than the parent metal in the as-welded state. Artificial ageing gave some increase in strength, full postweld heat treatment much more. Welds made with 5556A filler metal were always tougher than the equivalent welds made with 4043A filler metal, the Latter also being more sensitive to heat treatment.
Tolerable defect sizes for welds in 13mm plate and critical defect sizes for welds in 3mm sheet were calculated using published procedures.