Drill Rod: oil & water hardening?

[Treven Baker]

I am wondering what the difference between oil and water hardening drill rod is. What would happen if I cooled water rod in oil or oil rod in water? I have quite a bit of drill rod that is not marked so I don't know which it is. Also what are the advantages and disadvantages. Where could I get good info on this subject?
Thank you,
Treven.

[SGW]

I'll make an attempt at this; probably some of the others know more than I do about it though.

Oil-hardening doesn't have to have quite as fast a quench to harden as the water-hardening does. (Water cools better/faster than oil.) Therefore, you can probably quench oil-hardening in water, although it may warp or crack more than it would if quenched in oil, but if you try to quench water-hardening in oil it may not harden as much as it should.

At least that's my guess....

[Thrud]

Check Machinery's Handbook or US Steel's "The Making of Steel" or metallurgy books in the library or university for complete info.

SGW is correct - quenching w1 in oil makes the interior harder than the exterior - producing a tendency to break in use. O1 requires a slower quench to produce the right Carbide and grain structure for full hardness. It will usually crack if quenched in water.

[Treven Baker]

Thrud, do you know of any way of telling what is what in my unmarked drill rod pile?
Thank you both for responding.
Treven.

[SGW]

No idea how to tell the difference, but I wouldn't worry too much about it. If you talked to a commercial heat-treater, they would gag at the very thought of trying to do proper heat treating with a propane torch and a coffee can full of water or oil.

If there is a color code on the end of the rods, red is *probably* water-hardening and yellow is *probably* oil-hardening, but not necessarily. That seems to be the coding i generally see, but I don't think there is any solid standard; it depends on the manufacturer.

[Thrud]

Some scrap yards have machines that can "kind of" sort the stuff out for recycling. You could also contact the chemistry, engineering, or physics department in your local University and ask if they can do Mass Spectrographic Analysis for you. This will tell you by exact percentages all of the elemental components in the sample.

Or, just use the oil quench anyway! On small sections of W1 it should not matter because it will still rapidly cool in the oil. Do not bother to water quench - if you do, and if it is O1, it will likely crack from the quench.

W1 (AISI-C1095) only hardens to about 1/8" inch anyway. Remember to temper (if required) the part immediately after quenching as a delay in tempering is a major cause of cracking as well.

[snorman]

As I recall from my time with working with
O1, it will air quench quite well in thin sections (1/2 inch or less). I'm guessing that W1 won't. Haven't really seen any of that stuff (W1) so I don't know for sure. Might be a way to sort it all out. Cut a small piece off each rod and torch it cherry red and allow to air cool. A quick pass with a file will tell the story. Good luck.