oil temp for quench

rotor

rotor

Joined
Mar 18, 1999
Messages
184
what temp would be best for cable damascus using soybean oil.i was searching the neti had gotten temps ranging from 100 to 160 deg f ive read that warm oil diapates heat better than cold oil at what temp will you get the most efficent heat transfer. the thing is the cable damascus im producing has good edge holding capability but is not real tough.last month i was finishing a blade but it would not harden at the tip so i decided to quench it in brine so i got a blade made of the same material it was a blade i was not worried about screwing up i heated the brine to 160 and edge quenched it no problems everything went great but i went to heat treat the other i used hot warter out of the tap about125-130 quenched it and cracked the edge
redface.gif
didnt think acouple of degreeswould matterim getting ready to heat treat a knife im selling for 150.00 and im alittle quench shy but i want to give the buyer best possible knife with out destroying 2 weeks worth of work
 
I quench any damascus at 125 deg. It disperses the heat faster than cold oil. Make sure that you immerse the whole knife at once, because any part that is left out of the oil will act as a wick and catch the oil and possibly your hand on fire.
Hope this helps.


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A Knife is no more than an Iron Tooth
 
People preheat their quench oil to maintain repeatability. If the oil is 100 degrees in the summer and 30 degrees in the winter you will not have any consistency in hardness. By keeping my quench oil in the range of 100 to 130 degrees, I maintain good repeatability.

BlacksmithRick@aol.com
 
I thought we heated the oil to lessen the shock to the steel.
Did both blades come from the same cable?

Brine should be faster than water.

Oil will be less of a shock to the steel, and less chance of cracking.
I heat my vegetable oil to about 100.
Cable is tricky sometimes.

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Sola Fide
 
I just watched Mike Bell quench a cable damascus Katana in a tub of water that was drawn straight from the tap. The katana was coated with clay (1/8") on the part that was to remain soft and the blade was heated in an upright gas forge by being drawn back and forth until it reached critical temp. The katana will probably have a thicker x-section than the blade you are treating. If you leave the bulk of the grinding till after the heat treat, there sould be no warpage problems.
I personally use transmission fluid heated up to 300 deg in an electric skillit and leave it for one hour and then unplug and leave till cool. I use 52100 which has a different transformation curve than the cable, which I assume to be a simple steel with about .8 or .9 carbon. The cooling rate of the cable would be about 1 sec. from 1400 deg to about 800 deg.
The heated fluid will dissipate heat faster because the fluid can move quicker. The blade will heat the fluid which causes it to rise, being replaced by the cooler fluid. When you heat something, Watch the fluid. If you heat the sides of the container, it will come up the side.
For hardening, I would recommend an oil of at least 170 deg. If it doesn't get hard, you have lost nothing and can try it another way if needed. Let me know how it came out.

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Ray Kirk http://www.tah-usa.net/raker

[This message has been edited by raker (edited 11-04-2000).]
 
130-160 is the range I like to have the quench oil in. For most of the reason listed above. It lessens thermal shock, and cools quicker than cold oil. Cold oil will actually form a vapor pocket around the hot steel, which gives and insulating effect.
For a standard type of hardening, the steel must get from critical to less than 400 degrees in 6 seconds or less, with this in mind, any hotter than 180F, and the transformation won't be complete. The higher temps (300+F) are getting into Marquenching temps where a different matrix is being formed in the steel.

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Ed Caffrey "The Montana Bladesmith"
ABS Mastersmith
www.caffreyknives.com

[This message has been edited by Ed Caffrey (edited 11-04-2000).]
 
i heat treated at about 160 did a double quench. the 2nd quench i did an edge quench cleaned it up hand shapened it on a wet stone
tested the edge chopping a 2x4 in half no defects stays good and sharp and takes impact well and with the diferntial heat treat didnt see the need for any temper cycle.
 
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