I'm wondering if anyone could give me a rundown on heat treating or whatever I need to know about a unknown leaf spring material. It's awfully thick but it forges down pretty good and I just cannot seem to get the heat treat right. I've been bringing up to critical temperature and quenching in canola oil with no results because it is still soft can anyone help me???

Do you know what the original application was?

Thomas mentioned a spring that he worked with one time that was funky.

I once ran into a low alloy strain hardened leaf spring that you couldn't quench harden.  If it was easy to forge even in thick section then I would be suspicious.  Have you taken a scrap piece up to non-magnetic or higher and quench in cold water to do a break test on it?  *Always* a good idea to start with such a test *BEFORE* you invest time in an unknown piece of steel.  I've even run into a time when we wanted mild but the scrap piece was high C!

No I haven't but that's why I rely on this group. I always see useful information and all the topics. I will try a scrap piece of the same material and let you know how it turns out when I water quench it but it will probably be tomorrow as it's too late this evening but thank you very much

31 minutes ago, BIGGUNDOCTOR said:

Do you know what the original application was?

Thomas mentioned a spring that he worked with one time that was funky.

Scrap yard pull?? I know, not much help!!!

Unfortunately as well I have made a awesome survival blade and a meat cleaver that are ready to go but terrified to try!!!! Because the smaller blade would not harden !!!!!!!

I've learned a lesson as you said and will try the heat treat before all the work from now on!!

Start with mild quench solutions and work your way up to severe quench solutions. How many different quench solutions have you tried? How many are left to try?

Well unfortunately, curiosity got the best of me so I went to the shop and heated. the forge up.When I did I got a piece of scrap leaf spring to critical and then quenched it in the cold water and it absolutely worked!!!!!!!!!!!!!!!!!!!!!! I want to thank Thomas powers and big gun doctor for the replies!!!!

It is hard as nails and the file scates right off!!!!

2 minutes ago, bubbyh said:

Well unfortunately, curiosity got the best of me so I went to the shop and heated. the forge up.When I did I got a piece of scrap leaf spring to critical and then quenched it in the cold water and it absolutely worked!!!!!!!!!!!!!!!!!!!!!! I want to thank Thomas powers and big gun doctor for the replies!!!!

It is hard as nails and the file scates right off!!!!

Thank you Glenn as well!!

too bad there isnt a heat treating pinned post that explains this stuff,  Wait there is, never mind 

Where the coolie??!!

I'm pretty new to this sight so excuse me!!?????!!!!

If you water quenched I hope you tempered it immediately.  If not don't be surprised if it cracks.

It was scrap but I definitely will the real stuff I'm making, thank you sir. Explain, if you don't mind???

There's a lot more info in the heat treatment section of the forum.  However, whenever we quench a piece of steel with enough carbon to harden, it creates a lot of stress within the steel.  Tempering removes some of that stress.   Even if you don't hear the dreaded "tink" when you quench and you see no cracks immediately afterwards, the stress can crack the piece later if it's not tempered.  A few months ago I had made a blade from "mystery steel" that I quenched just before I finished up for the day and didn't feel like tempering it that night.  Everything looked good when I set it down, but the next morning there were two cracks in the blade close to the tang. Those cracks went all the way through and were in a location such that I couldn't grind them out or redesign the blade so it's scrap.  I wouldn't have trusted the blade anyway after what I saw.  As far as I know it's always a good idea to temper immediately after quenching.

6 hours ago, Buzzkill said:

There's a lot more info in the heat treatment section of the forum.  However, whenever we quench a piece of steel with enough carbon to harden, it creates a lot of stress within the steel.  Tempering removes some of that stress.   Even if you don't hear the dreaded "tink" when you quench and you see no cracks immediately afterwards, the stress can crack the piece later if it's not tempered.  A few months ago I had made a blade from "mystery steel" that I quenched just before I finished up for the day and didn't feel like tempering it that night.  Everything looked good when I set it down, but the next morning there were two cracks in the blade close to the tang. Those cracks went all the way through and were in a location such that I couldn't grind them out or redesign the blade so it's scrap.  I wouldn't have trusted the blade anyway after what I saw.  As far as I know it's always a good idea to temper immediately after quenching.

I didn't temper the piece as it was late and also scrap but now you have my curiosity stirring and I'll check it when I get home. Thanks for the good info and I'll let you know what I find.

Happened to a friend of mine too:  late night quench and so left it un-tempered on his workbench and next morning 3 pieces!