View Full Version : Drill Rod Dilemma

08-31-2005, 06:11 PM
I picked up some drill rod... silver steel whatever you want to call it. However I'm not sure if it is air or oil hardening. Is there a way to tell? The end has a red paint code if that helps any.

Thanks Tim

08-31-2005, 06:26 PM
All the water-hardening I've seen in my shop has had red paint on the end. All the oil-hardening I've seen has had yellow.

08-31-2005, 06:44 PM
That seems correct. If in doubt, oil can be used to quench air or water hardening drill rod with no ill efects.

08-31-2005, 06:55 PM
Thanks Guys

09-01-2005, 07:54 AM
If you try oil and it doesn't harden enough...try water.

09-01-2005, 09:36 AM
The color coding doesn't mean much. Each mill has it's own system. The oil hareding rod I get from McMaster Carr has been ; Yellow, green, silver. All in the same order.

09-01-2005, 09:52 AM
Wow. All the O-1 I've ordered had red on the ends, yellow was given to A-2. I use more A-2 than anything as it's so much easier to heat treat and doesn't change much in dimension.

Like others suggest - heat till a magnet isn't attracted, allow to cool in air. If it's hard after that it's an air hardening alloy, if not reheat and quench in slightly warm oil. If it's hard after that it's likely O-1 or something similar. If you heat it again and quench in a light brine and it's not hard it's just not a tool steel.

Jerald Ware
09-02-2005, 07:12 AM
We had a man who did all our hardening who could "spark" a piece of steel on the grinder and tell the type.

I could never get the gist of that, all spark patterns looked the same to me.-Jerald

09-02-2005, 08:41 AM
Yeah, when I went through trade school they taught us the "spark" method of testing steels. At best, it is a totally uneducated guess. I've heard lots of stories of the old timers being able to tell where a piece of A36 came from by the spark, and personally, I think its a load of crap. You might be able to tell carbon content, but telling the difference between 1030, 8630, and 4130 might be challenging. If the project you are working on demands a performance spec from the alloy, just go buy a known piece.

Paul Alciatore
09-02-2005, 11:38 AM
I've seen text books with pages of spark patterns for various types of steel. I even experimented and checked out the patterns with some scraps I had. There are definitely differences in the patterns. A dark room helps.

I uuspect it may have worked fairly well then there were a couple of dozen alloys but with today's selection of hundreds, if not thousands, I doubt that it is really reliable.

Paul A.