The Stovebolt Site Forums The Parking Lot Big Bolts Technical savvy re: Welding steel to cast iron?

Howdy All --- I'm hoping there might be a "real" welder in the crowd that can help with this one. And since it involves a "Big Bolt", wasn't sure where else to ask.

I'm installing a Dana 80HD rear axle in my '46 1-1/2 ton and need to relocate the spring perches. I was trying to avoid removing the old and just mig weld some 3'8 in. plate on top supported with tabs welded to the axle tube. From what I've read/been told, using 308L stainless makes for a very good joint between the SS & cast, but the real issue turns out to be how to properly anneal the metal post welding (keep the heat in for about 8-12 hours). Can't drop this big sucker in a bucket of sand, so does anyone here have any experience or suggestions? Another approach? Any real world advice will be much appreciated.

Hy Tango,I'm probably not understanding you correctly, I thought all axle tubes were steel, where are you needing to weld steel to cast iron?

I found this procedure from a Link about aftermarket suspsnsion systems crenweldge had posted earlier. Not exactly applicable but you can gather some great tips and basic info from it for your application.
http://www.watsonsuspensions.com/CMSPages/GetFile.aspx?guid=ac292487-3336-4100-abf2-a1dffd55d04d

As 3B suspects, and I'm pretty sure, you aren't welding anything at all "cast iron". The Dana axle tubes are steel and the spring perches are either forged steel or cast steel, in any case easily weldable (as you can see they were welded on to start with).

I strongly suggest you remove and reattach the original spring perches, that will give you a more professional and likely more reliable solution. An added benefit of welding the spring perches on where you like is you can measure, adjust, and fix any issues you may have had with pinion angle. Here is where you start to learn about that part.
http://www.stovebolt.com/techtips/driveline/setup/index.html

Grigg

Thanks Guys --- What appears to be cast are just the spring mounts. And they may well be cast steel, not iron. They are definitely magnetic and "spark" like steel but do have a crystalline interior like cast. It is also necessary to alter the width of the perches. I am hanging original replacement springs which are 2-1/2" wide and the 1998 Dana/Chevy had 3" so metal had to be removed to fit the original sized U-Bolts. As noted, the perches were welded onto the tubes so I am hoping that might indicate steel that can be welded "normally" but would still like to try and anneal slowly to avoid any possible problems with cast metal of any type.

Off to read up on Grigg's list...thanks again and I'll let you all know what I discover.

Here are some perches on a Dana 80 that I modified to fit narrower springs on the slightly wider perches. In this case the spacing was already correct.
https://picasaweb.google.com/lh/photo/ydeakI-wVgnJH8jITsPJ99MTjNZETYmyPJy0liipFm0?feat=directlink


Better yet is if you have the original rear axle to the truck it very likely has 4" tubes same as the Dana 80. Remove those perches to use on the Dana 80. I have a pair saved from my 2 ton axle for the next time I get in this situation.

Grigg

Unfortunately, the '46 axle is quite different (tapering & smaller OD). And having to relocate the pads out by 7/8" on each side complicated things a bit too. Who would have guessed the '46 was set wider than the new "wide track" option Dana? 40-1/4" on the Dana to 42" on the Art Deco.

And great info in the Roadranger PDF! Gracias!

Well, if you can scrounge a 48 and later (not sure how late) GM 1.5 or 2 ton rear axle with round tubes they are likely 4" and likely for narrow springs like you need, you could use those spring perches just measure to be sure.

Use the same nickel-alloy stick welding rod that's used to repair cast iron to run a penetration pass on the spring perches. Reverse-polarity DC current is the best approach for getting a smooth bead with good penetration. Once that bead is well-bonded to the cast steel, use 7014 or 7018 reverse polarity DC rod to build up cap passes and bond well to the steel axle tubes. Post-heating or slow cooling should not be necessary, but you might want to spend 10 minutes or so after each pass stress-relieving the weld bead by peening all over with the pointy end of a slag hammer. Bury the housing in sand overnight if you're worried about the rate of cooling.
Jerry

They had a Dana axle factory the next town over from me and a friend of mine worked there, I got a tour one Saturday.
The spring pads as well as the plug welds at the tube to housing joint were done at room temperature with a MIG welder, didn't seem to be anything fancy.

Grigg

Thanks to All --- I may be overthinking this but given that the pads appear to be cast, I want to make sure I don't screw the pooch and wreck a high dollar axle. Or worse yet, have it fracture and crash cause I went off without doing some basic homework.

Might wind up hiring a "real welder" to do this part.

Hey Tango: I'll put my 2 cents in to. I've worked in job shops for 35 years and any casting could be steel, cast Iron or a mixer. Any thing but pure steel should be pre and post heated and welded with Nirod stick. Also you can get a asbestes blanket and wrap up your axle while it cools. You can do a spark test with a grinder to compare sparks on steel to your casting. Cast Iron will not cut with a torch,it will only melt. Another test is weld with a steel rod and take a file and see if the weld is hardend,if it s it's cast Iron. If in doubt use Nirod

Its not going to take much of a weld to stick your spring seats on the banjo housing. The U-Bolts do a lot of the holding. I have taken quite a few U-Bolts off of spring ride, and have the spring seats fall off.

Many thanks to All --- After talking to a local builder/welder who has done a lot of rear end swaps over the years, I went ahead and mig welded the suckers. Thorough pre-heat, lots of peening and about two hours worth of diminishing heat. There are new pix on my Flickr Album at the link below...

https://www.flickr.com/photos/tango88/sets/72157626526227672/