5160 HT question.

D

DustinHall

Joined
Dec 31, 2008
Messages
687
I am not actually positive it's 5160, it's an old leaf spring, but, for simplicities sake let's say it is. Ok, I'm wondering if this is a forgiving steel and will let you re-HT it? Lots of fire upon quench kind of screwed up the first one for me and I'd feel better about doing it again. Another thing I'm wondering is if it would be ok to quench in water? The blade and convex edge are very thick, is there still a high risk of it cracking? I know it won't warp. Thanks to anyone willing to help this newb. :)
 
it is fine to quench it again. I would stay away from the water with it, it is a deep hardening steel and takes an experianced had to quench in water without cracking, but you might get lucky.
 
This is a couple of years back but the only two I ever put in water CRACKED.
After the normal oil quench when they weren't quite cool enough to hand hold
what could it hurt to get them a bit cooler? (haste makes waste)
Ken.
 
DustinHall said:
I am not actually positive it's 5160, it's an old leaf spring, but, for simplicities sake let's say it is. Ok, I'm wondering if this is a forgiving steel and will let you re-HT it? Lots of fire upon quench kind of screwed up the first one for me and I'd feel better about doing it again. Another thing I'm wondering is if it would be ok to quench in water? The blade and convex edge are very thick, is there still a high risk of it cracking? I know it won't warp. Thanks to anyone willing to help this newb. :)
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first things first, it is a forgiving steel in that you can re heat treat it (if its 5160). DO NOT USE WATER. it will crack and no mater how thick it is it can warp. what are you using as a quenching liquid now. another thing is to quench the whole blade, dont just edge quench this steel as you will not get the results you want. also how much of the quenching liquid are you using. i use a gallon and it is really not enough for doing anything large. get a different oil to quench in, go to a animal vet supply place and get some vet grade mineral oil. it will be quite thin and will cost around 12 or so bucks a gallon. now this will get you by with out having to buy parks AAA at 120 bucks for 5 gallons. heat up the oil to around 100-120 degrees. you can do this by heating up a random chunk of steel and dropping it in and letting the oil warm up. when you quench the blade there will be flames if the blade has a lot of mass and is able to vaporize some oil before the steel has dropped below the flash point for the oil vapor. also don't swish the blade around in the oil at all to make it cool faster. this can warp your blade as it disturbed's the vaper jacket around the blade. but it only disturbed's it on one side if your swishing it back and forth. this will cool one side of the blade faster then the other causing it to warp in the direction of the colder steel. after quenching you most likley will have decarb on the surface of the steel that is not hard and that might fool you into thinking its not hard but make sure you remove it in a place and check before you think you need to re heat treat. o and one more thing, well actually 2 more things. first is the temperature you quench at. it needs to be hotter then 1475 which is when a magnet stops sticking to the steel, you need to get it to 1525-1550. so you need to go past just a little when the magnet stops sticking. Now you must soak the blade for around 5 minutes at the 1525-1550. i soak mine for 7-8 min and have great results. but i don't know how your heating your steel i use a pid controlled forge so its very very accurate and precise. if your just using a fire then you will have to keep a close eye on it so the temperature is even. to do this you move the blade in and out. it the tip gets to hot you can remove the blade from the fire and the the heat even out and then put it back in. its bad to just stick the blade in there and leave it for 7 min. now when i say soak it for at least 5 min i mean once it comes up to temperature then leave it at that temperature for 5 min. it allows everything in the steel to properly mix and dissolve, this is very very important. i think that's all, o wait on more. after you quench the blade you need to temper it. but not knowing for sure what steel it is i would say start at 375-400 for one hr and check edge hardness. if its still to hard bump it up 25 degreas and re temper for an hr. this should help. now I'm of to the operating room to get a screw in my hand.
 
JT....I'm not sure I want to know.....but what were you typing with?

Good luck Dustin....I can use this info. too....thanks!

Brad
 
Thanks JT. I appreciate you taking the time to write all that especially with your broke hand but, I do know most of what you told me already. Still doesn't hurt to hear it again and I did get some good tips out of it! :) What temp would you suggest tempering at for a large thick edged camp knife? Anyway, the blade is a huge camp knife... 11 3/4" blade, 2 3/4 wide, a hair under 1/4 thick. I'm using a mix of old motor oil and canola oil. I don't have the money for good oil atm but, hope to get some in the near future. I heat the blade in my coal forge which does not have a temp gauge on it so yes, I have to be careful. Thanks for the tip about not edge queching. That is what I did the first time and it caught all the oil on fire in the big pan I had and was almost a disaster. I had to throw the blade on the ground and run and get a towel to smother the fire. :eek:
Well, good to know that I can give it another go. I appreciate all the replies.
BTW, how's the hand doing, Jarod? Heal up soon! You make some sweet knives.
 
ATF will work a bit better than your cocktail. it will also flare up a little less. I have been doing an edge quench for ten years with great results.
 
Thanks for your input Bill. Problem is ATF isn't usually free and right now I am broke so I have to use what I can find right now or not HT any steel until I can save my pennies for some better stuff. The edge quench I did seemed to work great on the first half but, I can see how quenching the whole blade in a few gallons would cool it more properly to form more martensite and not pearlite. Kind of hard to edge quench and keep the blade moving in a huge flare up that's burning your hand too.... that's how the first attempt went.
 
Dustin you can probably score some atf for nothing by going to a tranny shop and asking for some clean used fluid and explaining to them what you are using it for. if you don't want to edge quench that is ok with me. good luck and have fun
 
I was curious about the no edgw quench too. I have seen several people edge quench and getting a pretty nice hamon.
 
the way i see it is like this. why edge quench? what does it give you with this type of steel? the steel is such a slow quenching steel that i have herd that it can affect the edge by not quenching the whole blade. also what do you gain by having a softer back. some people say well it wont break when its bent. but is super bending really a good test for a knife. and with a soft spine yes it will bend but it will stay bent and not flex back. now if you heat treat the whole blade then you have a blade that will take the same amount of force to bend but will come back to straight (depends on how much you bent it). now you can flame draw the spine and lower its HC hardness giving it a spring temper with a harder edge and that will give you the hard edge and a springy spine. but i just dont see any advantage in just edge quenching and leaving a compleatley soft spine. maybe on a large chopper it would be ok but even then why not spring temper the spine. but thats just how i see it.
 
I would have to agree with you JT. Drawing the spine back with a torch seems like a better way to achieve the results we want with just an edge quench. Thanks everyone.
 
Unless my info is wrong - wouldn't be the first time :) 5160 will air harden back close to a spring temper on its way down from critical. That is how spring shops work custom springs without having to re HT. Could someone out there confirm that or correct it. I have a big 5160 blade I just forged to shape a couple weeks ago that I hope to finish soon and could use the input!! Thanks all.

Brad V
 
I also recommend drawing the spine/tang with a torch, on wide blades it works wonderfull, just clamp it in the vice edge down and the edge will stay cool if you watch your colors. A normalized blade isn't going to be hard enough to be usable.
 
JTknives said:
........any advantage in just edge quenching and leaving a compleatley soft spine. maybe on a large chopper it would be ok but even then why not spring temper the spine. but thats just how i see it.
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If you fully austenize 5160 and do NOT quench the spine, it will revert to pearlite, which is NOT "completely" soft. And, true, you MAY get some air hardening.
Pearlitic 5160 can be one tough customer to flex/bend.
It's a looooooooooooooooong way from soft.
 
john0270 said:
I also recommend drawing the spine/tang with a torch, on wide blades it works wonderfull, just clamp it in the vice edge down and the edge will stay cool if you watch your colors. A normalized blade isn't going to be hard enough to be usable.
Click to expand...

My bad.....I didn't mean to imply you could use a normalized blade....just making reference to edge quenching. :)
 
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