Welding regular steel to cast

[maddog]

Are there any professional welders here that might be able to shed some light on welding regular steel to cast? (as in the type found on diffs) I'm hoping to do this with my mig welder.

I've read somewhere about using high nickel rods, would it just be a matter of using a high nickel reel of wire in the mig? Is there any pre-heating required?

[Steve F]

I also looked in to this a while ago and seem to remeber that pre heating was a very good idea. I have some manuals around somewhere in PDF format I'll see if I can dig them up and email them on to you if you like.

Cheers
Steve

[maddog]

I've since found out that you need to use a high nickel reel/rod to weld with. Unfortunatey you're looking at $600-700 to buy a reel of Nicore 55, so I may have to look at some other options.

One option would be to get a shop to do the welding that already has the required wire reel. Another would be to just use a stick welder with nickel rods which are significantly cheaper.

[maddog]

Originally Posted by Steve F

I also looked in to this a while ago and seem to remeber that pre heating was a very good idea. I have some manuals around somewhere in PDF format I'll see if I can dig them up and email them on to you if you like.

Cheers
Steve

yeah any info you've got would be good thanks Steve.

[Steve F]

One of the manuals I have is pretty basic and probably wont tell you much you dont already know but It did have this on welding cast in the ARC welding section

A special-purpose rod used in repairing cast-iron,
such as automotive blocks, cracked heads, transmission
cases, and various farm equipment, is EST, although
there are several brand names in the trade just for castiron
rod. Most rods for this purpose have a high nickel
content. Although these rods are available, it doesn't
mean that cast-iron welding is easy. Any cast part should
be thoroughly preheated to 400° F or better to prevent
cracking after the localized heat of welding is induced
into the part. Parts, depending on their size, can be
heated in an oven or with a rosebud tip on an oxy-acetylene
torch, using temperature indicating paints to tell
when you have it evenly heated to the proper temperature.
Even then, there can be cracking problems.

Cheers
Steve

[Gojeep]

I know the knuckles are cast steel but cant remember if the diff centre is as well or cast iron?? Be worth checking that out first.

[AussieRCBasher]

all or most of the people on Pirate 4x4 who bullet proof or do up their diffs just weld straight to the pumpkin on diffs. they just mig or tig the tubes into the diff centre or weld the brakets for 4 link applications right to the diff.