Cast Iron Machining Repair

[LSPSCAT]

I have a casting with an 1.25" DIA hole that has been drilled 1" from its correct location. The assembly consists of mating flanges and the mating component has already been machined correctly. The section thickness at this point is approximately 8". Material is ASTM 126 CL B. If the section was not so thick I would be comfortable with weld repair, however, with such a thick section I am looking for any suggestions other than scrap it! Good size castings so I hate to see it go to waste - 4000 lbs.

 

[arunmrao]

There are 2 options. Use a threaded mild steel insert and plug the hole. Alternately weld repair the hole. I a comfortable with filling thick section castings. Thin sections normally pose a problem. The welding rod should be of machinable cast iron grade.

It is always sad to see a good casting go waste.


If you think education is expensive, try Ignorance.
- Andy McIntyre


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[LSPSCAT]

We talked about a threaded insert, however, the new thru hole will core into the threaded insert. I am just concerned about welding into a 1.25 inch hole..i guess its only 4 inches each way.

The mating flanges are clamped in compression, however, the assembly is structural and carries high shear loads longitudinal to the joint.

 

[MikeHalloran]

Make a BIG insert of MS, say the size of the flange OD, with tapped holes to accept the flange bolts, and between them, counterbored holes to mate with tapped holes in the casting. Sink it into a big counterbore in the casting.



Mike Halloran
Pembroke Pines, FL, USA

 

[LSPSCAT]

Yeah, I could actually see that working, maybe I can drill out around 2.5" then place a mild steel insert and just use that. Its a big rugged casting, I just hate explaining to the owners the creative machining we used as a go around!!

 

[MikeHalloran]

Tell 'em it's for durability, like putting helicoils into aluminum parts before they get stripped.





Mike Halloran
Pembroke Pines, FL, USA