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Cast iron to mild steel

Posted: Thu Jan 27, 2022 9:18 am
by Josh.mulcahy
Ok i have a cast iron gib of a machine the adjuster tang broke iv bolted true both parts and held with locktite
Im looking to weld bead now just give extra strength ( looks rough but just ground raw until welded)

I have following machines
Stick
And a acdc tig

I was told from different people use 9/29 dissimilar arc rods on stick

Cast iron rods on stick

And told use the 9/29 rods flux knocked off used as filler on dc tig

Preheat part weld fully
Either burry in dry sand or damp sand iff wrapped in an apron
Or let sitt on the wood cast iron stove top and when fire goes out after few hours will cool with it

All opinions welcome

Re: Cast iron to mild steel

Posted: Sat Feb 05, 2022 12:02 am
by 77cruiser
Braze or silicon bronze maybe.

Re: Cast iron to mild steel

Posted: Thu Feb 10, 2022 12:08 pm
by drizzit1aa
NOTE: just saw you don't have a MIG. Leaving the rest of this for anyone who does and can't properly preheat. TIG weld with Silicone bronze will fill it in. Don't see it adding much strength though given it's a soft material.

I have welded quite a few steady rests. Mainly the knuckle at the top hinge where they let it fall back on itself putting it under a good amount of stress, around 150 lbs. of shock force. I have had great results just using a MIG welder, 70S filler.

1/4" to 3/8" bead, take a good hard center punch and peen it everywhere you can get the point to hit. That stretches the weld before it can cool, shrink and crack the cast. Wait until cool to the touch and repeat until finished.

Use higher heat than you would think because of the short bead and turn the WFS up higher than it should be at the given voltage that helps to keep it cool (counterintuitive I know but it works). If need be, grind excess bead off after peening. Peening it doesn't help much that has penetrated so too much penetration and you'll have a pre-load that will either crack or reduce its strength. Start at, and finish the shorter ends, always alternate sides to keep it straight. If it pulls it will crack so take it slow.