Sciencemadness Discussion Board

Proper electrode material for arc melting steel

metalresearcher - 16-9-2023 at 10:06

Sometimes I melt (stainless) steel using a DC arc welder with carbon rods. But after melting, the steel gets brittle as it absorbs carbon and transforms to cast iron. Once I used thick steel wire embedded in refractory cement ending in the bottom of the cavity where the steel is to be melted. That works, I connect the steel wire to the anode and use a carbon rod as cathode. So, when the steel is molten, the steel bath acts as anode. But, yet the metal gets brittle as well.
Might be tungsten rods can be a solution, but W also oxidizes quickly at steel melt temperatures.
Commercial EAF melt shops in steel industry use C rods as well, but they have much better control over the composition of the steel bath.
Does anybody have ideas / experiences ?

mysteriusbhoice - 16-9-2023 at 14:57

if you have inert gas you can probably use tungsten as your electrode

Rainwater - 17-9-2023 at 04:10

O2 is blown into the melt which produces CO that bubbles out of the mix. Any Fe that reacts first to form oxides will be reduced back into metal by the carbon content.
Its a secret process for each manufacturer so the exact details are hard to obtain and are batch dependent

Twospoons - 17-9-2023 at 13:01

Are you sure its not just the fact that its cast thats resulting in brittleness? Typical steels get tougher through hot or cold working, then tempering. You dont get that with a casting.