casr iron welding

[mcstu]

I stupidly cracked a piece of big cast iron on the frame of my tractor today. Its a big mess, way beyond any thing I would attempt to repair. One crack is about 6".

I am going to have to check a few welders out to get them in to do this. If I get them to do it while in place, its all vertical and over head welds. Can anyone give me some ideas on what is the proper method to repair 1" thick cracked vertical cast iron? So I can help narrow down the candidate to hire. Its an antique tractor, so if I were to try and replace the part, the part to be replaced would likely cost unbelievable amounts of $ and may not even be available.

[Al T.]

You might try brazing,

but you should wait for others to answer your question, there are people here that would be more qualified to advise you.

[Mike Sherman]

mcstu, the person you choose to repair this should talk about several things: 1) Try to identify the exact type of cast iron, 2) Stopping the crack from propagating, possibly by pinning, 3) Totally removing the crack, by either carbon arc gouging or grinding, 4) In a joint on a tractor I would consider only full penetration welds, 5) Adequate preheat up to 900 deg. F, 6) Maintaining the interpass temp. 7) Removing all contamination from the cast, preheat will help with this, 8) Using an electrode made for cast iron, not a standard steel one, 9) Postweld heat treatment or slow cooling of the weld.

[mcstu]

What about TIG welding?

Are there any experts on TIG-ing cast iron. I have heard recently that this is the best way to repair cast iron.

STU

[Mike Sherman]

I have tig welded cast iron, what do you want to know?

[boilerman]

if you can't find a weldor to do it ..you may want to look into this as an alt. fix http://www.metalocking.com
seen this done and have done similar repairs on water jackets of old j.d.'s

[chip hayden]

if it's at all practical[size of piece], i would suggest using oxyfuel with cast iron rod and anti-borax flux. smut a large area around the crack with acetylene, pre-heat slowly and evenly with a rosebud[s] till smut burns off. then with neutral to slightly oxidizing flame work flux coated filler into prepped crack[after gouging i use a carbide bur].
the carbon in old castings is not evenly dispersed and takes various forms which increases the difficulty of welding. by continually fluxing and "washing" with the filler rod, the weldability increases. you can peen the haz and weld as you proceed-i think it helps.
after the weld is completed, keep the rosebuds on it for a while[barely discernible red color], then pack weld and surrounding area with fiberglas insulation[the stuff in your house] and leave it for a day. uncover, blend repair as you wish with grinder and you have an real good color match in a few days.
it's labor intensive and hot but, i've gotten the highest percentage of acceptable repairs with this method

[Jerry]

I too have tig welded and arc welded cast iron. I would try the arc welding process on any cracked cast iron. Tig works good for building a pad or etc.., just seems to be somewhat crack sensitive compared to the arc process.

[MattGehman]

cast iron repair without welding

I work for a company that repairs cast iron mechanically. We have been doing this since 1942. We work on everything from 4 cylinder engines to 6000 hp 16 cylinder locomtive engines. Check out our site www.metalocking.com, I am sure we could help you with your existing problem.

[MattGehman]

Locomotive Repair

For those interested in my above posting, I have included a photo of the completed repair.

[Guest]

If you could post a picture of the crack, it would help in the diagnosis.