Heat Treating question

M

Musicman88

Joined
Sep 25, 2020
Messages
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Hey everyone, I recently finished a knife and a scythe with 4mm thick O1 steel. I brought the knives to non magnetic in my coal forge, held them in a little more and quenched them in veg oil (sunflower oil) . I used an old xxl steel pot as a quench tank. When i dunked my steel I had no flare up at all with either blade, just some smoke. I checked the steel with a file and the file skates on the surface of the blades but i want to make sure they are hard before i start making handles for both. I tempered both blades and got a deep straw color out of them. as i dont have special ht ovens i went very basic and old school with the whole procedure.

Is it possible to have no flare at all when quenching or did i mess up the temp?
If the file skates on the surface of the blades (like glass) is it guaranteed that my blade is hard?

Thank you in advance!
 
Actually, a quench with a big flare up is usually a sign of a quench done wrong. You should net get a flame if the bade is quenched and stays below the oil until it cools down. What causes those huge flare-ups on FIF is the smiths pull the blade out of the oil almost immediately. This creates the situation with a red hot blade covered in flammable oil.

The other situation that sometimes causes a flare up is if you let your tongs or the rebar handle on a damascus billet get too hot. The smoke from the quench or oil on the tongs/rebar may ignite.
 
Awesome good to know! I was was worried that somehow the knives lost temp from the forge to the quench. Although the scythe (which is a full tang design connected to the blade) wasn’t submerged fully and it still didnt flare up. But if the blade wasnt hard then the file wouldnt skate right?
 
I actually decided to give the scythe an edge (chisel grind) and it does cut, but as this is the first time im working with O1 i dont fully know what can or should dull the edge out to have some kind of comparison as to how much of an edge it can take. (See what i did there? It will cut :p)
 
Just an FYI, but O-1 isn't the best steel for a forge HT. It normally requires close temperature control and a 10 minute soak. 80CrV, 1084, 1075, and similar steels with low alloying are better choices for a HT with little or no soak time and unreliable temperature control. That said, a forge HT is not the best for any steel. You may get it hard, but many of the parameters you want may be off. Toughness is usually the first sacrificed.

Larrin's book is an invaluable resource for data on steels and HT.
 
Stacy E. Apelt - Bladesmith said:
Actually, a quench with a big flare up is usually a sign of a quench done wrong. You should net get a flame if the bade is quenched and stays below the oil until it cools down. What causes those huge flare-ups on FIF is the smiths pull the blade out of the oil almost immediately. This creates the situation with a red hot blade covered in flammable oil.

The other situation that sometimes causes a flare up is if you let your tongs or the rebar handle on a damascus billet get too hot. The smoke from the quench or oil on the tongs/rebar may ignite.
Click to expand...
I'm sure there is nothing floating on top of the oil that could cause it to flame;)
 
I have thought that for a long time. They say it is just regular medium/fast oil ... but I have my doubts. The current rumor is it is Parks AAA. The fact that it bursts into flame the second the hot blade contacts it and the flames shoot straight up in the air, then disappear is very suspicious. A cup or two of naphtha or other light and very flammable hydrocarbon floated on the oil would create an effect very much like what we see.
They have had contestants burned/singed in these flare-ups.
I have quenched hundreds ( maybe over a thousand) blades during my life and never had a flare up like the ones on TV. I have used probably a dozen commercial quenchants as well as things like mineral oil and vegetable oil.
 
I always thought it was the temp of the blade that made the oil flame so much but I’m just a hobbyist and havent dwelved into metallurgy all that much, excuse my ignorance :p. I’m a composer by trade who really likes knives and for the past year has been making them :p
 
Stacy E. Apelt - Bladesmith said:
Actually, a quench with a big flare up is usually a sign of a quench done wrong. You should net get a flame if the bade is quenched and stays below the oil until it cools down. What causes those huge flare-ups on FIF is the smiths pull the blade out of the oil almost immediately. This creates the situation with a red hot blade covered in flammable oil.

The other situation that sometimes causes a flare up is if you let your tongs or the rebar handle on a damascus billet get too hot. The smoke from the quench or oil on the tongs/rebar may ignite.
Click to expand...
I'm sure there is nothing floating on top of the oil that could cause it to flame
Musicman88 said:
I always thought it was the temp of the blade that made the oil flame so much but I’m just a hobbyist and havent dwelved into metallurgy all that much, excuse my ignorance :p. I’m a composer by trade who really likes knives and for the past year has been making them :p
Click to expand...
Welcome to the addiction.
 
Stacy E. Apelt - Bladesmith said:
I have thought that for a long time. They say it is just regular medium/fast oil ... but I have my doubts. The current rumor is it is Parks AAA. The fact that it bursts into flame the second the hot blade contacts it and the flames shoot straight up in the air, then disappear is very suspicious. A cup or two of naphtha or other light and very flammable hydrocarbon floated on the oil would create an effect very much like what we see.
They have had contestants burned/singed in these flare-ups.
I have quenched hundreds ( maybe over a thousand) blades during my life and never had a flare up like the ones on TV. I have used probably a dozen commercial quenchants as well as things like mineral oil and vegetable oil.
Click to expand...
We have to look at a lot of these shows with our bull$*&$ filter on. There are a lot of things that they have to do to just make it a show.im sure guys aren't being pulled aside and asked how they feel about something while their blade is in the forge ect. It's a show and if you look at it like a wacky contest sorta like Junkyard Wars it's awesome. I just wish they would bring that element out more. I don't think it would harm anything and people would understand that all of the smiths are working outside the box and not doing day in day out work. Who cares if they add a bit extra fire then.
 
Storm W said:
We have to look at a lot of these shows with our bull$*&$ filter on. There are a lot of things that they have to do to just make it a show.im sure guys aren't being pulled aside and asked how they feel about something while their blade is in the forge ect. It's a show and if you look at it like a wacky contest sorta like Junkyard Wars it's awesome. I just wish they would bring that element out more. I don't think it would harm anything and people would understand that all of the smiths are working outside the box and not doing day in day out work. Who cares if they add a bit extra fire then.
Click to expand...
Agreed, some of the blades they make are actually quite impressive given they only have x amount of time to do them. The flames make great slow mo shots!

From my limited experience working with far from ideal equipment (i mean this wholeheartedly) on an apartment patio a lot of the work is very improvised and requires a lot of on the spot ingenuity, which is one of those elements i trully admire in knifemaking and smithing, even woodwork for that matter. Respect to all of you!
 
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