サブマージアーク溶接金属の組織とじん性におよぼす鋼板中Alの影響(第1報)

抄録

To study the effect of Al in 50 kgf/mm² class C-Mn-Nb steels on weld metal microstructure and toughness, single-pass, bead-in-groove tandem submerged-arc weld metals have been made at 49 kJ/cm. The work was based on a 1.5%Mn-0.5%Mo wire, with two kinds of highly basic agglomerated fluxes and one low basicity, flux. Semikilled, Si-killed and Si-killed, Al treated plates of 25 mm thickness were employed.
The preliminary findings presented in the report showed that even small changes in weld metal Si and Al levels (e.g. 0.02 to 0.03% Al) could produce drastic deterioration in Charpy toughness (up to 100 deg C shift in 3.5 kgf⋅m temperature) when using some basic fluxes. Furthermore, the results indicated that achievement of high weld metal toughness with some basic fluxes might be difficult in high dilution welding of Si-killed, Al-treated steels having more than about 0.035-0.045% Al. The effect of Al on microstructure and toughness was found to be independent of its source (wire or plate).