Tempering and heat identification by color

[Ol'fogasaurus]

I think this might be of some help.

http://members.optushome.com.au/terrybr ... rtEtc.html

Temperatures of metal by color.

http://en.wikipedia.org/wiki/Tempered_steel

A bit more information on the same subject.

http://7now.com/tempering_steel.htm

http://www.ehow.com/info_8054672_effect ... nding.html

More information.

There is more that I can't find right now.

[winifredevw]

Cool, I've actually been looking into heat treating lately. The third link you provided seems to agree best with what I've been finding, as far as temp/color charts go.

Also understand, what looks dull red to one may look cherry red to another. I have a cheap infared thermometer that I'll use to try to back up what I percieve in different color ranges before I treat the real deal.

Carbon content also varies the color range signifigantly. Here's a link to a sticky on another site with some good info-

http://www.akfiles.com/forums/showthread.php?t=14475

[Ol'fogasaurus]

Very cool addition to the list! (pun intended) I think this is something that a lot of us either don't know enough about, ignore in the heat of the battle (pun not intended), or just don't always think about.

[SCOTTRODS]

I recently figured out the alloy has a significant bearing on what the colors mean as well.... The rules that are most common are for mild steel, if I read all those charts right (The ones in the first post seem to be that)... I haven't had a chance to read the entire thread posted by winifredevw, but sounds like there's a bit more info....

I've been dealing with tool steel lately (A2) and it's definitely different than most of the stuff I have read.

[Ol'fogasaurus]

I've been dealing with tool steel lately (A2) and it's definitely different than most of the stuff I have read.

Oh yes!

Spring steel is another one where heat is an enemy. I was watching a "How to" show last weekend and the statement was made that 400° turns spring steel into mild steel.

http://www.ehow.com/list_6805600_effect ... rings.html

http://publications.muet.edu.pk/researc ... pdf171.pdf

If you do a search on the effects of heat on spring steel you are going to run into a lot of information, more than I think is prudent to list here.

[Devastator]

I heat treated a 40L40 shaft recently by heating in a forge until it was no longet magnetic, then quenching it in peanut oil, (left over from deep frying turkeys). Worked well enough, although I didn't take the time to check the hardness before or after HT, other than a "file test". Either way, the shaft is working for perfectly in it's new role. Next time I make one, however, I'll check the hardness of it before and after, since I have a Rockwell tester here at work. I also have a temperature crayon for 40L40, (1600 degrees F), now too.

[Ol'fogasaurus]

Some people have all the tools!

[SCOTTRODS]

I guess I work with tools.... and there are some tools at work..... and some fairly nice folks too. But we have 2 Rockwell testers at work right next to one another..... I should figure out how to use them huh?

[Ol'fogasaurus]

An unused tool is an insult to the tool. A tool you don't know how to use is an insult to you (an old saying I just made up ).

Lee

[winifredevw]

I'm learning that hardening aligns the grain of the steel, but makes it brittle. Tempering at a lower temp is in order after the hardening process to give it "toughness".

[Ol'fogasaurus]

Yes, that is true. Cryogenics (http://en.wikipedia.org/wiki/Cryogenic_hardening) should also be understood. Do a search on the subject as there is more than Wikipedia has posted as I understand it.

[SCOTTRODS]

An unused tool is an insult to the tool. A tool you don't know how to use is an insult to you (an old saying I just made up ).

Lee

The tools I work around,.... they refuse to be useful. Once a tool.... always a tool. I have no unused tools in my tool box.... If I have it, I bought it for using. I like your old saying you just made up though.....