Please advise:confused:

Like many people just starting out, I've been working with salvaged steel that I've been given or found along the way. Since I usually don't even know where the pieces came from or what they were used for, I don't know how to treat them. I think most of what I have came from old farm implements (spring steel or one sort or another).

I know its guess work, but how would you folks suggest heat treating? I had one knife blade that wouldn't harden with oil, so I started the process over again, but this time using brine. It's being tempered as we speak. Is there a good order of quenching mediums to try? And will multiple hardening attempts weaken the blade?

Please fire away..... I need all the help I can get!

Happy Hammerin';)

there is advanced heat treating info in the knife sticky's

Steve,

I read the sticky and I'm still confused. My question is how to proceed with hardening if you don't know the type of steel. Was that what you were talking about in your testing to see if it is necessary to "soak the steel" before quenching?

Thanks For Your Patience:D

aprayin...

What I do is try a test piece (or two) of similar width and thickness as your final piece. Try an oil quench first - this is safest. test for hardness w/ an old file. If this doesn't work, try more aggresive quenchants such as water.
Use the successfully hardened test piece to also test tempering. Temper as much as possible and still have a functioning piece.

These comments refer to HT in general, not specifically to blades; and it may already be in the sticky mentioned by Steve.

actually the safest order is to try AIR first, then Oil, the water, There are many air hardening steels that may not react well to a oil quench

Very few air harding alloys in the old farm scrap stream though. I have run across a couple of old cold chisels that air hardened.

If you are using unknown steel then you HAVE TO do a test piece to figure out what works best for it. Learn to judge the grain size when you break it and how to modify it by changing your HT process. If you are not willing to do a test sample don't use unknown steel AND DO THE SAMPLE FIRST; don't spend the time foging something only to find out it's not hardenable (lots of farm scrap is mild or even wrought iron!).

Also beware of decarbed surface when testing.

Thanks Guys,

That really helps. Hadn't even thought of the air hardened varieties. The great thing about scrap is that it's just that, scrap. Don't mind testing and I love the practice.

Thanks again!

I too have a similar problem, lots and lots of hard steel I use around concrete block making and hard wearing metals in a concrete batch plant mixer, plus a ton of large concrete breakup gun broken bits.

So if water doesn't harden it, it probably isn't able to harden??

correct