Quenching with oil

It does if you pull the blade out too soon (or the oil is too hot). The oil used for quenching has a reasonably high vapor point (and flash point) and will not burn much upon quench. If ,however, you pull the blade out for an interrupted quench, the oil on the blade will burst on fire. Just stick the blade back in the oil and the flames will go out in a moment or two ( it does create a lot of smelly smoke).
You should have a tight fitting cover for any quench container. The container should be metal. And you should NEVER work with hot blades and quenchants without a good fire extinguisher rated for the type of fire you will have if you kick over a 2 gallon container of hot burning oil. Those little kitchen extinguishers will not cut it!!! Get a good 10-20# ABC unit. It is money well spent.I have a dry chem 20# and a fair size CO2 unit in the shop. It sits right by the anvil. No time to run to and look for it when a fire happens.
Stacy
 
so its based on removing available oxygen correct? I was under the impression it was an open faced bucket, and I simply couldn't figure out for the life of my why it simply doesn't burst into flames when a 1500 degree piece of steel gets thrust into it.
 
I have had some real nice oil fires while quenching in my basement shop!! I know stupid stupid stupid !!
 
The lip of the quench tank should be at least three inches or more above the oil level. That way the fumes from the burning oil soon exhaust the oxygen and extinguish the flame. If it is too full, the tank can boil over and cause a nice oil fire around the tank. Right rocketmann?
 
I saw on tv a demonstration of how NOT to deep fat fry a turkey.With too much oil and no one watching it boiled over !!! Very exciting ! ..For those who want to martemper/marquench in oil be warned that oil heated near the flash point is a disaster waiting to happen !!
 
Well, it never really got out of control just a lot of smoke and some 10" flames..Nothing a good fitting lid couldn't put out..But it sure stinks up the basement :D
 
Different oils also have different flash temps, peanut oil has a high flash temp and doesnt smell bad when your'e quenching either.
 
Ooh and opportunity to talk fire science! One of the reasons I am a smith is because I am a genuine fire bug and when I am not at the anvil I am also a firefighter and fire science was my favorite part of the training:D .

The liquid does not burn, the vaporized liquid burns. If you go entirely below the surface of the liquid there is no oxygen and there can be no combustion. This is where we get into air/fuel ratios, sustained combustion is actually a carefully balanced mixture of heat, fuel and oxygen, as anybody who has ever made their own gas forge nozzle can attest;) .

One instructor expalined how if one had the nerve and the time, they could fill entire room with LP gas to a point too rich for combustion and then safely strike a match or a spark, however if some fool opened the door while this was happening, all concerned would pobably die.

Back when I joined the fire service it was called the combustion triangle (heat sources, fuel, oxygen), now it is more a fire tetragon because they have added the fourth component of "unbroken chemical chain reaction" as tools for extinguishment have become more sophisticated. In order to kill any fire all you have to do is remove any one of these elements and combustion cannot be sustained. Stacy is right on target with the extinguisher advice but I would reserve that for fires that suddenly move outside of the tank, a forceful blast from an extinguisher directed into you tank could spray your fire all over the place. The best way to kill a quench tank fire it to cover it- remove the O2 from the equation and the fire cannot continue. Then wait for the heat to drop below ignition temperature before uncovering (the loss of the heat component taking the place of the removal of oxygen keeps the fire dead)

I used to do a trick at demos where I would time the removal of a hot piece of steel from oil and pull the vapor trail over my head in an arc allowing it to flash with an impressive display- KIDS DO NOT TRY THIS AT HOME- I am a professional IDIOT with many years of injuries to keep me oblivious to the danger! But it is all about heat and vapor with the oil.

Note: It is possible to so over heat your blade that when you quench the bubbles created are full of super heated gasses that will ignite when they reach the surface and get O2. This is why a good formulated quenchant is a safer choice as well, since they are designed to eliminate vapor jackets they will keep this bubbling to a minimum. Heck the #50 oil I use has a flash point that is much lower than other oils but I have never had a fire in it because I go entirely below the surface and there is virtually no vapor jacket.
 
Kevin , now that you've joined this thread - My comments about frying turkey -I don't know the Ms for turkey , do you get bainite or martensite ??...Don't overcook the turkey otherwise it will be hard to carve. Best knife is a 8" slicer , very sharp. Happy turkey day !!
 
And do NOT do this on a wood deck if there's a chance it will overflow. The turkey situation turned into a burnt down house.
 
mete said:
Kevin , now that you've joined this thread - My comments about frying turkey -I don't know the Ms for turkey , do you get bainite or martensite ??...Don't overcook the turkey otherwise it will be hard to carve. Best knife is a 8" slicer , very sharp. Happy turkey day !!
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mete, I think many of your questions would depend on the amount of elements in the turkeys diet. Lots of manganese mixed with its grain would have to increase hardenablility. And of course let's not forget the effect of how fine that grain is;). Even here I would take martensite over bainite - I hate tough turkey. Just as long as the very core is comprised of mixed structure of onionitic bread particles with packets of lathe type almonds intermigled with other meaty consitutents (I like little bitty shrimp). As always I would recommend a longer cooking at a reasonable temperature over a quick scorching, though some may choose to cook it several times between refrigeration. I think I would go with an 8-9" slicer as well.:thumbup:
 
Kevin R. Cashen said:
As always I would recommend a longer cooking at a reasonable temperature over a quick scorching, though some may choose to cook it several times between refrigeration. I think I would go with an 8-9" slicer as well.:thumbup:
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i have found that the repeat heat and refrigeration works well with a san mai core of bird with outer layers of softer whole grain
 
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