What consumables are better for welding over rusty, dirty steel?
As a general rule, steel surfaces should be cleaned of any oil, grease, rust and mill scale before using any type of filler metal or consumable for any arc welding process. These are all surface contaminants which can potentially adversely affect weld quality. However, sometimes complete cleaning of the steel surface cannot be performed. In these cases, the recommended consumables for “dirty” steels are those that form a slag, have deeper penetration, have a slower freezing puddle or have higher levels of silicon and manganese. These Lincoln Electric consumable products include, but are not limited to:
SMAW: Fleetweld® 5P+, Fleetweld® 5P, Fleetweld® 180, Fleetweld® 35
GMAW: SuperArc® L-56®, SuperArc® L-59®, SuperGlide® S6
GMAW-C (Metal Core): Metalshield® MC-6®, Metalshield MC-710XL®
FCAW-G: UltraCore® 70C, UltraCore® 75C, Outershield® 70
FCAW-S: Innershield® NR-311, Innershield® NR-305
SAW: Lincolnweld® L-50® wire, Lincolnweld® L-61® wire, Lincolnweld® 760 flux, Lincolnweld® 761 flux
Note: these consumable products may be inappropriate for use because of other variables, such as the need for out of position welding, multiple pass welding, applications requiring low hydrogen filler metals, etc.