Welding cast to steel

[sz0k30]

I see a lot of threads saying how difficult it is to weld cast iron. Just curious about welding cast iron to steel. Primary case is rear axles such as GM 12 bolts or Dana. Where the tubes are welded to the pig, some all the way around, some just thru the weld plug holes. Whats the story?

 

[PWC Repair]

I don't know, I just use my wire welder and it seems to work fine.

 

[Old Man Roger]

Pre heating and controlled cooling would be preferable. I think they recommend between 500 and 1200 degrees, closer to 500 is probably safer.

I've done smaller welds by just using a torch to warm up the area. You're trying to reduce cracking around the welded area.

 

[Old Man Roger]

Directing more of the heat to the steel while welding is a good idea, cast iron melts easier than mild steel.

 

[welder4956]

Are you sure it is cast iron and not cast steel? Drill a shallow hole in an area where it will not matter and see if the drill bit produces shavings or granules. Cast iron will produce granules and cast steel will make shavings.

That said, I would not expect to see grey cast iron used but more likely ductile iron. Ductile iron is weldable.

 

[Farrier]

Nonetheless, anytime axle housing tubes are welded to the center pumpkin, a jig needs to be used to prevent deflexion of the tubes.

Plug welding is appropriate from almost all applications. Only time I've seen tubes fully welding to the pumpkin is where a custom axle was made for rock crawling rigs or race vehicles.

 

[bonneyman]

I glean alot of knowledge off of guys on Youtube who are repairing old vises, which can be cast.

 

[Josey]

Biggest problem you'll have is that cast anything is full of air. That being said, when you weld it, all the impurities come out. It's like welding styrofoam to steel. Brazing is one of the best methods. Make sure your materials are at least clean on the surface level before you introduce heat.

 

[shawnspeed]

Cast Steel usually welds good...which is what I believe those housings are made from...

 

[matt_i]

Cast Steel usually welds good...which is what I believe those housings are made from...

Yes, I was going to point out....but you did...that cast iron and cast steel are very different animals with different uses. An axle built with a CI center housing would not last long if you ask my opinion.

 

[welder4956]

We weld cast steel valves and pumps frequently. Occasionally we will find casting porosity, but never had an issue welding it. Same with cast aluminum and cast stainless steel. Typically the naysayers are just repeating what they heard somewhere and have not actually welded it.

 

[thehighwayman]

Nonetheless, anytime axle housing tubes are welded to the center pumpkin, a jig needs to be used to prevent deflexion of the tubes.

Plug welding is appropriate from almost all applications. Only time I've seen tubes fully welding to the pumpkin is where a custom axle was made for rock crawling rigs or race vehicles.

x2
For a little extra, drill a little material out of the axle tube before plug welding.

 

[rsanter]

I have welded a number of them.
They are cast steel, not cast iron.
Get it very very clean, hit it with a grinder.
Heat it a bit with a torch and then weld it.
Many of the big narrowing companies TIG weld them, I have always MIG welded them with no issues