Had Alot of Fun with Unknown Leaf Spring -

R

rlinger

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Mar 29, 2002
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While waiting on epoxy to cure I was able this evening to take time out to play around with a sample of some leaf spring a machanic gave me a couple months back.

After cutting a sample and grinding off the rust to 120 grit flat it tested 47 HRc twice consistantly. I thought I'd take a shot at HT'ing it as 10XX. Ramped fast/moderately to 1200 F (about 1 hour to 1200 F) and let preheat there for 7 minutes, then ramped fast up to 1475 and soaked 10 minutes and quenched in ambient Tough-Quench. Tempered 1 hr/425 F. Before quenching, what I noticed upon opening the door to retreive the 3/16 inch thick sample for quenching was a big glob of black shadow moving about upon the steel. That told me it ain't time or temperature yet. But I quenched as usual just the same. Anyhow she tested 55 HRc after tempering.

So, I'm thinking now do a 5160 HT. So I do. Same thing except 1525 F / 10 minutes (its still about 3/16 inch thick). Same quench. Same temper. This time no shadows at all when I go to retreive for quench. I'm feeling good now. --- but, She tests 53 HRc after temper. Lots of fun and NO banana.

This was the very first time ever I have played around HT'ing a steel I had no idea what it was (except for one another maker sent me). It was fun and a pleasant distraction from the norm and I have absolutely zero idea where to go from here with it. Any HT ideas?

EDIT: I always forget to include all details. While grinding the steel throws a wonderful shower of sparks BUT after HT the decarburation (I did not atmosphere control it) was much more shallow than I expected. In fact decarb was very shallow, even after the 1525 F / 10 minute soak.

RL
 
I suprised it didn't come out as a crispy critter if it's 5160 Rodger. :D

Try this:
Burn a sock,

Reharden,

Temper at 325.

If it's 5160, you'll be ready to cut car doors off! :footinmou :)
 
It could be 9260, occasionally leaf springs are made from that, especially cadilacs if you happen to know the car type it's from. I have some I suspect of being that and it just doesn't get quite hard enough for a blade steel from my tests though it's good for tools, I made a hot cutter. I don't recall if you're a forger or a stock remover, but it you're a forger try a forge test. If it's really red hard then it could be the 9260.
 
Awp,

I am a stock remover.

Thanks for the info. The reason I went back and HT'ed again, today, as 10XX is because the first time (at 1475 F / 10 minutes) it appeared to be austenitizing. Today I soaked it about three minutes longer and all shadows were gone this time when I went to quench it. It still only tested 53 c after 425 temper. What I think might be telling me something is there is very little decarburation or scaling. Not nearly as much as should be for high carbon. I am beginning to believe it is medium carbon. At the same time I am no spring steel expert either. I think it will become part of the land fill.

RL
 
A couple things come to mind...

Did you grind the scale off before hardness testing?

Did you test before tempering? It may have never gotten full hard.

Why 425f and not 375F?
 
Awp, As far as I know 9260 was used by Steudabaker. Wayne Goddard had given me some a couple years ago. If I remember right I believe Jeff Carlyle had given it to him to try out. It got plenty hard enough for me but I don't have a RC tester....
 
Bruce,

Oh yes. I ground it clean and flat before testing. The difference between 53 to 55 HRc after 425 F tempering and what ever it may have been after a 375 F temper should not be enough to make it a blade steel, to me at least. Not knowing any better, I think its medium carbon. I do not know what type vehicle it came from. It was about 0.320 inch thick after grinding the rust off and about 2 1/4 inch wide. That's all I know about it except that it was originally 47 HRc before I HT'ed it, throws a nice shower of sparks and there is very little decarb or scaling (by comparison to what you would expect).

RL
 
In my Smart A$$ way Rodger, I was asking the same thing as Bruce. With 5160, there is a whole world of difference between 375 and 475. Actually 375 would make a pretty soft blade with most 5160. I rarely have to go beyond 350 and almost always stop at 325.

At 475 to 500, your back to soft spring temper.
 
Raymond Richard said:
Roger, Is that roast turkey done yet? :D :confused: :D
Click to expand...
That's very interesting, fellas. I have some pieces of what looks like truck spring that is 3/8" thick, and should behave about the same way, eh? I think I dropped some of the sections at Dave Larsen's shop a while back,so Dave has some to play with.
 
Make sure you have a severe quench (full hardening) and then temper to :eek: 375 F and you may have a good blade. I would bet on it.
 
Don, I took your and Bruce's advise and (once again dug the sample out of the trash) and HT'ed as I would 5160. This time I tempered at 350 F / 1 hr. It tested 54 - 55 HRc. Once again, there is no decarburation by comparison to what you would expect from a high carbon steel. That is my opinion but again I am nobody's spring steel expert either. BTW, I think I made a big mistake in that I believe I have been calling this 3/16 inch thick. It is not. It is 3/8 inch thick. Sorry about that.

I think it is on the edge but just too far away in carbon for our purposes. On the other hand I don't know the composition either. I gave it a shot and it was fun.

RL
 
Jason, it is possible the type quenchant was not optimal for this steel. Other than that I believe I cooled it as quickly as Tough-Quench permits. My major concern, beside austenitize temperature, was time at soak. I really do believe 13 minutes is enough and that is the ceiling I soaked at. If I can soak 3/8" carbon steel at 1475 F and then at 1525 F for 10 and then 13 minutes and never get decarburation, to speak of, I am guessing it ain't high carbon. But then what do I know, honest. I was just having fun and a break from the usual routine. A mystery steel to play with a little bit. I did learn something about modern vehicle spring steels though. It ain't a automatic given they are good for making blades from. My opinion anyhow.

RL
 
Roger, One of the things I have notice with certain steel is the thicker the steel is the less hard it will get. Have you got a way to thin it down to 3/16 and then run your ht?
 
I have to agree with you Rodger, although it is rare to get a car spring that just won't harden, it happens. Looks like you got a dud! :(
 
This is why I just stick with O1. :D After several years messing with it I know I'm on the verge of figuring it out... FWIW I tend to temper in the low ranges too, usually around 385. John I do have some of the spring pieces you left but haven't yet tried them out. When you coming again?

Roger it's interesting to read your methods. Can't wait until I get a good way to control temps. Thanks for the info, good stuff.
 
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