Welding cast to steel

[mach9]

I have a rearend housing in the race car that has steel axle tubes that are pressed in and then plug welded to a cast iron center section. These tubes are known to come loose and spin in the center section which is not good. I want to weld all around the joint where the tube goes in to strengthen this area. It it my understanding however, that using a standard mig-weld here (HH 187) is practically useless. If this correct? Is there a rod I could get for the stick welder that would properly weld these two materials together? Any and all advice is appreciated. MJ

[chip hayden]

ok, i"ll take a stab at this;
i don't particularly like welding the tube to housing the way you suggest. the line of force is in the same direction as the weld. however, if you must, fixture well, preheat, alternate 180 degrees stitch weld, and your power supply should do it. if you are worried about cracking and ductility [and insufficient heat input], sma [stick weld] with a ni-rod might be an option.
If you stay with the original weld design[plug weld] try enlarging the weld window and adding another[window] with the above mentioned procedures.
p.s. the weld window should be big enough so the perimeter weld does not completely enclose the center and the axle tube should still be visible.

[Fat Fab]

The housing is most likly cast "steel"ot iron and your er70s2 mig wire will do fine. Or you can use god old e7018 3/32"


I would weld an inch on the left then go to the right tube and weld an inch keep going back and forth, so you don't warp the tubes.


TJ

[Amos F.]

I have had the tubes "spin" in the center before. Not fun when you are hard on the brakes going into the corner fast. I never welded the tubes all the way around. Always about an inch on the front and an inch on the back;front and back being in relation to the direction of travel of the car. Also if I was you I would consider changing the original tube out for some chrome moly tubing if your rules allow it. You need to get away as much unsprung weight as you can.
Amos F

[BillC]

The housing is most likly cast "steel"ot iron and your er70s2 mig wire will do fine. Or you can use god old e7018 3/32"

TJ

TJ, What makes you say that it is probably cast steel?

[BillC]

Also if I was you I would consider changing the original tube out for some chrome moly tubing if your rules allow it. You need to get away as much unsprung weight as you can.
Amos F

Amos, the only way to reduce the weight is to use thinner wall tubing. which will increase the bending deflection of the axle tubes. Bending of the axle tubes also causes bending of the axle shafts. How thin can you go without causing a problem?

Regards,

[jamesdart]

yup you can mig that, but you should really have a fixture. lots of shops mig the center to the tubes. the factory plug welds are not meant to withstand 1,000 hp launches at the strip.

[JalopyBldr]

I just received a pair of ladder bars from S&W Race Cars, Inc.. Their directions state that GM & Dana axle tubes are pressed into the center section which is made of "cast STEEL" and that the tubes are sometimes spot welded. It further states that "This method of attachment will not hold up to the torque applied to the rear housing of a drag race car. The joint between the center section and the axle tubes should be welded ENTIRELY" (caps are mine).

The directions also state that MIG welding is preferred and TIG is not necessary. Stick welding should be avoided.

[BillC]

So GM and Dana use cast steel... Cool!

[Amos F.]

Billc

I have been looking for a bent one in my scrap since you posted and I can't seem to find one to measure. So I will have to take a guess from memory, please don't hold me to it, it should be close though. I am using this on oval tack car about 550 horsepower. The tube was not quite 3/16 I believe. Yes I have bent them with light hits and hard hits into concrete and other cars. I have also had my Dodge pickup rear ended from a parking spot with a stock rear end in it and driven into a hydro pole by a 5 ton truck with the worst bend rear end I have ever seen. My Dad watched it happen and told me that the rear end actually straighten up quite a bit after the truck drove away. I still can't convince him you have to bend metal beyond where you want it to stay bent when in the break. He still wants me to save the axle shaft out of that rear end, LOL!
Amos F

[mach9]

Thanks for all of the replies guys. On the advice of an experienced local welder and this forum, I decided to go ahead and MIG weld it. Stood the assembly up vertical, and started with 4 spot welds spaced at 90 degrees. Kept alternating short welds until I had welded the whole circumference. Not exactly a roll of nickles. A roll of pesos maybe. I think it will be ok though. Thanks again for the help. I'm using S&W ladder bars too, BTW. MJ

[metal mad man]

Yep, I believe that is a cast steel center section(or bell ends).I just welded a vintage quickchange rearend up for my 1929 Plymouth coupe rod I'm building.The same situation,steel axle tubes and cast steel bells.I did however preheat the center section just in case,welded it up with my Hobart 250 (.030 wire) burned the bead in real good! The end stubs had a 1-7/16" hole in them so I grabbed a length of 1-7/16" round stock used for machining that my buddy had,made sure it was true and straight and it slide through the center of the assembled axle like a glove! The holes in the bells that were used for bolts or rivets,I plug welded those up.It turned out awsome! Just make sure everything is where you want it.I spent almost a week taking measurements and so and so on before I welded it up.I had to cut 4" total out of it because it was just to wide.Any questions on what I did let me know!