Defect In Cast Iron?

[Oldmanandhistoy]

While scraping in the ways on my new mill I came across a very hard spot in the base of the machine. My questions is can I do anything about it or am I just stuck with it?

Anneal it with a blow torch maybe?

John

[Big_d]

I have had this problem before and tried this, for me heating it didnt work. Not saying it wont work on your machine but I think the hard spot that got me was a piece of nickel. I was able to get mine with some carbide scrapers.
Good luck
Cheers
Daza

[Oldmanandhistoy]

I have had this problem before and tried this, for me heating it didnt work. Not saying it wont work on your machine but I think the hard spot that got me was a piece of nickel. I was able to get mine with some carbide scrapers.
Good luck
Cheers
Daza

Hi Big_d,

Thanks for that , I’ve stoned it below the bearing surface so until the way wear down it’s not too much of a problem. If a blow torch isn’t going to work I’ll just ignore it.

Jhn

[NC Cams]

It depends what the defect is and the annealing/draw temp of same.

Some metals have a very narrow annealing temp range. Heat too low, no change. Heat too hot and they can actually air harden as bad if not worse than before when it cools.

When the area was NOT melted into full solution during the initial pour, you really can't rely on the smoke wrench to solve your problems because you have something of an anomaly that may/may not respond in a predictable fashion.

The other issue is that of distortion and residual stress. Localized heating can distort the area (usually due to shrinkage) when it cools. Again this depends on the temp but most guys tend to "make it cherry red" as thats the "perfect temp" for just about ANY malady.

Temps of this level will shrink the metal and create residual stress and distortion in/of the part when cooled. You could actually make things worse, not better with a smoke wrench.

Probably the safest and most tedious method would be to grind the area. Diamond, ceramic or silicon carbide stones might/should cut the area. All in all, take your time and BE PATIENT. Haste makes garbage.

[jollydog]

The hard spot occur from phosfor or if the foundry has made a repair on the cast (welding)

[Oldmanandhistoy]

Thank you NC_CAMS I always appreciate your detailed and informative posts.

John