Cast iron or cast steel?

tjb

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Hello to All.

I am in the process of changing the axle/wheel assembly on an old farm fuel trailer. I am using the front-end of a 1959 Chevrolet Apache pickup truck for the change-over. If you know those old trucks, it has a leaf spring/solid axle/tie rod assembly - perfect for this application. In order to stabilize the steering mechanism, I have fabricated a plate of 3/8" cold-rolled steel which I've permanently welded to the tie rod but only tack welded to the axle.

Here's my issue. The axle is cast, but I'm not sure if it's cast iron or cast steel. I've cleaned up the portion to be welded with a grinder, and it appears to be steel (nice and shiny), and I've drilled a shallow 1/4" hole, and it 'chips' like steel instead of 'crumbling' like most cast iron I've ever worked with. If it's steel, I can MIG weld my fabricated plate to the axle just like I did to the tie rod. But if it's iron, it needs to be welded with nickel rod, so I'm told.

Does anyone know:
a. If the front end is definitely one or the other? Again, 1959 Chevy Apache front axle.
b. If the tests I've described above are conclusive one way or the other?
c. If there are other tests I can/should perform.

I'm told one test is to weld it up then go at it with a sledge hammer and see if the weld breaks. Seriously. That was suggested. (Some of the old school farmers around here are more inclined to do things the fast way instead of the textbook way. But don't laugh. In my experience, they're usually right.)

Sure would love some guidance on this one. Don't need to be tooling down the road with 80 to 100 gallons of off-road diesel when a weld breaks.

Regards,
Terry
 
My first comment would be to trust the old timer before a textbook. While I can't say for sure, I would bet on the axle being steel. Way back in the mid-70s I worked in a pipe foundry. They cast "cast iron" water pipe. With the metalurgy involved, it was the same as cast steel, with a few esoteric additions. So, my money is on steel. I do assume you're using a straight axle and springs? Such parts go back long before the second WW. A BIG hammer is the best test.
 
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Touch it with a grinder. Cast steel should throw a lot of sparks and be pretty bright. Cast iron throws far fewer sparks. Subjective, I know, but if you can find a video to see the difference once, you can't miss it.

Edit: here's a decent one;
 
How about the axle being forged instead of cast. That'd be steel, no doubt. Hit it with a file, if its' bright underneath, it's steel, not iron.
 
My first comment would be to trust the old timer before a textbook. While I can't say for sure, I would bet on the axle being steel. Way back in the mid-70s I worked in a pipe foundry. They cast "cast iron" water pipe. With the metalurgy involved, it was the same as cast steel, with a few esoteric additions. So, my money is on steel. I do assume you're using a straight axle and springs? Such parts go back long before the second WW. A BIG hammer is the best test.
Not a 'straight' axle. A full axle, but it is cast. I'm guessing steel as well. My understanding is the big difference is the amount of carbon in steel vs. iron.
 
Touch it with a grinder. Cast steel should throw a lot of sparks and be pretty bright. Cast iron throws far fewer sparks. Subjective, I know, but if you can find a video to see the difference once, you can't miss it.

Edit: here's a decent one;
Thanks. I saw that video on youtube, and it's part of my reasoning for leaning towards steel. Already cleaned up the weld area with a grinder, and it is definitely bright and shiny - like steel (see my original post). Thanks for the post.
 
How about the axle being forged instead of cast. That'd be steel, no doubt. Hit it with a file, if its' bright underneath, it's steel, not iron.
I'm pretty sure it's cast, Tom. Seems to have casting marks on it. However, it is nice and shiny - much like taking an 80 grit grinding disc to cold-rolled. I'm thinking 'steel' more and more.

Thanks for the post.
 
Beam type straight axles are either forged or cast steel. On the NASCAR modified of the 50's and 60's we used to use a rose bud torch to change the camber. You can't do that with cast iron. Weld it with 7018 low hydrogen rod or equivalent. I've never heard of cast iron axles, but that does not mean that there aren't any.

Roy
 
Beam type straight axles are either forged or cast steel. On the NASCAR modified of the 50's and 60's we used to use a rose bud torch to change the camber. You can't do that with cast iron. Weld it with 7018 low hydrogen rod or equivalent. I've never heard of cast iron axles, but that does not mean that there aren't any.

Roy
Thanks, Roy.

In your opinion, will MIG weld work?

Regards,
Terry
 
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