WELDING EXPERT OPINION NEEDED

[Guest]

ok, We all know you can not weld cast iron, or can we?

I'm told that the only way to get a good cast weld is to heat the entire assemble, or the weld will split on the ends.

Then there is "buttoning", which is a series of tapped studs that follow the crack, and then ground smooth.

Since the only welding i do has a "J/B" infront of it, are there new arc welding rods which make a cast repair work well?

[nearchoclatetown]

Try "40 Cast Iron Repair Secrets" by Rich Fercy. The book cost $10. Phone no. 1-800-673-7099. He explains the pre and post heat and sells a special rod. His stuff is expensive and I never tried it. I have brazed cast sucessfully. A friend had a motor "stitched", with the pins or threaded studs, like you described. It does work. I personally would do everything except weld it.

[Peter J.Heizmann]

Hi, Tommy...

For starters, I am in the "make good parts first" business. (Grey and Ductile Iron Parts.) However, for welding, there are rods out there today that tout they can do the job. Pre-heating the parts in the general area of the weld to avoid crystallization of the carbides is a most important facit.

Below, I copy a similar opinion I submitted on February 12, 2002. (Look in the "Search" area and there were various other similar submissions I made over the years on the forum.):

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02/12/02:

Chuck, very interesting experiences you forward.

It brings another thought to mind concerning welding Fe (iron) parts, especially those trying to weld cracks/leaks in exhaust manifolds.

Most manifolds are made of grey iron, not ductile iron, which is somewhat of a semi-steel. There are rods out there now that tout "grey iron friendly". I do not know enough about them to comment in depth, but, they must work to some degree. However, one key step if you try to save a "rare" manifold is to pre-heat the area to reduce thermal shock. Simply picture an ice cold peace suddenly being shocked with the heat of welding. The carbides in the iron "crystalize" (under a microscope, and, even the naked eye, one can actually see crystals in white, or, silver colors. The area away from the target appears grey, which it should be.)

Over the years, a few customers asked about welding cast iron. My basic answer is to go for it if it is not a safety related casting, such as a manifold to stop a leak. If it was a safety related casting, I tell the customer to do his own research as I will not have anything to do with it, and, change the subject ASAP. If my company ships a defective casting, I demand they return them for us to scrap.

Sort of digressed from Bill's original queries about chrome plating, however, the message remains: What type metallurgy are we dealing with, is it really worth trying to salvage or buy a new/NOS part, and, "preparation".

Regards, Peter J.

[ 02-12-2002: Message edited by: Peter J Heizmann ]

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Peter J. Heizmann

1972 Triumph TR-6

AACA #383299 Life Member

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Now, before I forget, if it is a "non-load atmosphere" of the parts, go for it. If it is a "load atmosphere" use your better judgement.

[Guest]

thanks peter,

this site makes it look easy

MUGGYWELD.COM

[Peter J.Heizmann]

Interesting site, Tommy...

Must agree with the problems of rods with a high Nickel content.

Nickel creates an austenitic (Austempered) metallurgy. (e.g...Austempered Ductile, of which we pour, is used in "high wear" applications by most customers.) Excellent for wear characteristics.

Bottom line, in my opinion, is do some research on what atmosphere will the welded piece be submitted to, such as, load, no-load, high heat, vibration, and, so on.

Tommy, contact me for any further help...my access to Donsco's "think tank" of metallurgist', of whom, know a lot more than I do, is at your disposal.

Regards, Peter J.