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1095 didnt harden


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Hey all, I have a little utility intergal I've been working on. I finally got it where I wanted before ht'ing and decided to give it a shot. I heated it up twice to just past the recalesence point, (as it cooled it very obviously "flared") and on the third heat, just past the recal point, I quenched it in peaut oil @ ~120º F, then straight into the oven @ ~ 475º F for an hour. But after it cooled, a file bit easily into the blade. Do I need to go a lot higher than my so-called recalesence point? It is known to be 1095 and I had thermometers for the oil and oven. Any insight would be appreciated.

Thanks

JM

Edited by JM Wands

Blade

The blade, elegant
Slicing through the sweet, warm breeze
with a precise hit.


Sam Wands (10 years old)





Gold for the merchant, silver for the maid;
Copper for the craftsman, cunning at their trade.
Good! Laughed the baron, sitting in his hall;
But steel---cold steel---shall be master of them all!

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peanut oil at 120 should be fine

475 oven for one hour should be fine

 

how long did you hold in the peanut oil (was the blade fully quenched)

are you SURE you passed the Aus Temp ???

President - Georgia Knifemakers Guild

ABS Journeyman Smith

 

"Wisdom and experience are built of bricks made from the mud of failure." - Mike Blue

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no,, I am not sure,,, I could see the bubbles coming off the blade pretty cleary and thought they had stopped but,,,,how long do you think it shouldve been in the oil?

thanks

jm

Blade

The blade, elegant
Slicing through the sweet, warm breeze
with a precise hit.


Sam Wands (10 years old)





Gold for the merchant, silver for the maid;
Copper for the craftsman, cunning at their trade.
Good! Laughed the baron, sitting in his hall;
But steel---cold steel---shall be master of them all!

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that might have been confusing, there were two seperate questions

 

1: did you hold the blade in the oil long enough to ensure the transformation to martensite (did it get hard)

 

2: while bringing the blade up in temp are you sure you passed the Austenite Temp for 1095 (1425 to 1450 deg F) before you quenched the blade

President - Georgia Knifemakers Guild

ABS Journeyman Smith

 

"Wisdom and experience are built of bricks made from the mud of failure." - Mike Blue

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magnets dont always tell you what you might think

 

a magnet tells you when the steel has passed currie temp not necessarily Aus temp

 

 

for some further informative reading

 

http://www.bladeforums.com/forums/showthre...rie+temperature

Edited by stephanfowler

President - Georgia Knifemakers Guild

ABS Journeyman Smith

 

"Wisdom and experience are built of bricks made from the mud of failure." - Mike Blue

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1095 has to be quenched fast to miss the nose of the curve in the itt chart.Around .05 of a second or something.Make sure your quench tank and forge are close together so there is no delay getting the blade to the tank.Dont trust a magnet,thats another bladesmith myth,it wont tell you when youve reached critical,and will lead to problems.You could get a good pyrometer or a heat treat furnace,that would solve it. :)

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1095 has to be quenched fast to miss the nose of the curve in the itt chart.Around .05 of a second or something.Make sure your quench tank and forge are close together so there is no delay getting the blade to the tank.Dont trust a magnet,thats another bladesmith myth,it wont tell you when youve reached critical,and will lead to problems.You could get a good pyrometer or a heat treat furnace,that would solve it. :)

 

You don't have to QUENCH it fast! The OIL needs to be FAST!

The oil needs to drop it from around 1500 degrees to under 1000 degrees in about 500 milliseconds - 1/2 sec.

It could take you 2-3 seconds to get into the oil as long as the steel didn't go below your quench temp. But, once you get into the oil, the oil speed needs to be fast enough to drop you to below about 1000 degrees in under 1/2 second.

That's a HUGE misunderstanding.

That's the big problem with using off-beat oils. That's why using the correct oil for the steel type is so important.

For instance, Parks 50 is a FAST oil! Used for 10XX steels, W1, W2, etc.

Then, Tex. A is a MEDIUM speed oil for stuff like 5160 where the nose slows down to about 3-4 seconds.

 

 

When in doubt use a magnet, I never trust my eyes. Also ,there is nothing wrong with letting it sit in the oil until ambient. Strait to the oven is not that crucial.

 

 

That magnet only gets you close! And not very, at that.

Non-magnetism is a product of a reaction of the carbon atom, which exists in ALL steel. Regardless of the steel type, nearly all of them go non-magnetic at 1413 degrees. FAR below the temp we need to be quenching our most common knife steels.

Straight from the mouth of Mike (Fitzo) Fitzgerald.

Thanks, Mike.

Edited by kbaknife
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That is pretty accurate - you need a fast oil. Peanut oil is not too bad, but it may be a bit on the slow side. Try using some agitation to reduce the vapor phase - it will also speed up the oil. Using a fast oil like the Park 50 or Houghto-Quench K will also help. The timing is a bit off, you have a bit more time than 1/2 second, but not a great deal. Remember the TTT curves or the CTT curves are for thin sections and small pieces. The thermal mass will push the curves to the right and down some.

 

I would recommend going to a higher austenitizing temperature too - around 1625F or so would work well - or a bright cherry red - almost orange would be a fair estimate by color...these temperatures are based on Timken's Practical Guide for Metallurgists - an excellent little book - I use it a lot.

D. Scott MacKenzie, PhD

Heat Treating (Aluminum and Steel)

Quenching (Water, Polymer, Oil, Salt and Mar-Tempering)

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thanks fellas,, I'm thinking it wasnt hot enough. For some reason I was thinking that right above "recalesence"(sp) i wanted to quench. Maybe thats how hot I need it to normalize,? I will try hotter. Thanks again,

cant wait to show you the finished piece.

jm

Blade

The blade, elegant
Slicing through the sweet, warm breeze
with a precise hit.


Sam Wands (10 years old)





Gold for the merchant, silver for the maid;
Copper for the craftsman, cunning at their trade.
Good! Laughed the baron, sitting in his hall;
But steel---cold steel---shall be master of them all!

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Usually I think the rule is check with a magnet for loss of magnetism, then soak for a few moments more, which I would imagine would push the temp to where it needs to be.

 

It's kinda how I go about it. And checking with a file afterwards, I get a skating effect.

Beau Erwin

www.ErwinKnives.com

Custom knives

Bcarta Composites

Stabilized Woods

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I don't remember if it's decalescence or recalescence, but for 1095 when the shadows run totally off the part you want to harden it's ready. This is a bit hotter than non-magnetic. You can get it hotter to both ensure it's hot enough and to guarantee you have enough time to get it to the quench, but if you go much over 1550 deg.F for very long grain growth can happen. :o

 

I'm not saying it'll ruin the blade at all, just that the grain won't be as fine as it possibly could be. Kinda nit-picky, but if you're trying to wring the highest performance from steel the ragged edge of disaster gets closer and closer as you push the boundaries of what's possible. :lol: I usually let it get just a bit hotter than it absolutely has to be just to ensure it'll harden. For small parts like gravers I even (gasp!) water-quench 1095. Remember, on simple steels we only use oil for the safety factor. Water is faster. Just don't forget and water-quench 5160 or O-1! ;)

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Actually,getting it to the tank without delay is important.a delay getting to the quench tank can drop your temps quite a bit.A student of mine was having this same problem.His tank and forge were to far apart,and of course you need a fast quench media.Polymers are better than the oils.

Edited by mark stephen
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I olive oil quench my 1095. My quench tank is right next to my forge- that 1/2 second is inclusive of the time it takes to get the knife to the quench tank! "room temp" air counts as a quenchant too. If you have to run 5 seconds across the shop to get the knife in the quench, that's precious heat lost. And if you have the steel hot enough that 5 sec in room temp air doesn't bring it below 1500 then I'd say you got it too hot in the first place.

 

My first thought was- decarb? keep digging at that steel until you get to the hard part :) 1095 is pretty hard to actually mess up (but i've tried :D )

Kristopher Skelton, M.A.

"There was never a good knife made from bad steel"

A quiet person will perish ~ Basotho Proverb

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Did you check with the file between the quench and temper?

Before you temper if 1095 got fully hardened a file won't touch it, after you temper it might depending on the temper cycle.

And if you check right after the quench you can try again if it isn't fully hard without wasting the time and energy of a temper cycle.

 

ron

Having watched government for some time, it has become obvious that our government is no longer for the people. If the current trend continues, it won't be long untill armed rebellion is required.

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Oh yeah baby,,, its hard! The knife,,, the KNIFE is hard.,,, thanks

jm

 

i guess thats an old bladesmith joke,,, sorry,,

Blade

The blade, elegant
Slicing through the sweet, warm breeze
with a precise hit.


Sam Wands (10 years old)





Gold for the merchant, silver for the maid;
Copper for the craftsman, cunning at their trade.
Good! Laughed the baron, sitting in his hall;
But steel---cold steel---shall be master of them all!

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