Abstract:
The aim of this investigation was to determine whether the composition of a shielded-metal arc-welding
electrode coating affected the low-temperature impact toughness of austenitic stainless-steel weld
metal. It is generally accepted that increases in the δ-ferrite and nitrogen contents result in a decrease
in toughness at low temperatures. Weld metal from electrodes with a basic coating also generally
exhibit better toughness than those from rutile (acidic) electrodes. An increase in basicity was expected
to decrease the number and size of inclusions, which in turn provides a tougher weld metal. Three
commonly available potassium–rutile E308L electrodes were used, complying with the E308L-16 and
E308L-17 specifications. Analysis of the electrode coatings showed very similar chemistry and basicity.
Significant differences in the inclusion contents of the weld metals were observed: the E308L-17 weld
metal had a lower inclusion content (1.4% by volume) than the E308L-16 weld metal (3.7%). The former
had higher impact toughness at all temperatures, despite a slightly higher nitrogen content. Regression
analysis confirmed that the inclusion content had a significant effect on the impact toughness at all
temperatures.
