FORGERS: Quenching?

[Howard Faltz]

Curious as to how many of you use Cryogenics and what kind? What other types do you use to get desired results? I.E. Water, oil, snow!!, multiple dips in different media? Your opinion on the different methods available.

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Howard A. Faltz, Owner
Arizona Knife Source
"Keep it Sharp"
Luke 22:26
www.azknife.com

 

[Ed Caffrey]

Howard,
For those steels that contain small amounts of Cr(chromium) like 5160 and 52100, multiple quenching in oil, followed by sub-zero in liquid Nitrogen does the trick for me. On my damascus blades (1084/15N20) a single quench with a sub-zero. (multiple quenching has little to no effect on simple carbon steels)
If you are asking what type of oil.....I use plain old vet grade mineral oil. I wasted a lot of time and money discovering that most commercial quench oils are 99% mineral oil anyway, and that the other 1% is either paraffin, or beeswax. As for the Nitrogen, I have a large tank that requires filling from the local welding supply store about once every 3 months.
Opinions? Well, from my experiments I have found that simple steels (10XX) do not derive any benifits from the multiple quench, however, those steels that contain some, but less than 7% chromium, gain considerable cutting/edge holding from this type of quench. When the sub-zero treatment in incorperated, even more is gained.
The best cutting damascus blades I have ever produced were a mix of 52100/5160 that recieved multiple quenches and sub-zero treatments. Due to the materials being so close in element content, contrast was very minimal, and most did not want them because the patterns were too vauge.
http://www.mtn-webtech.com/~caffrey

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Ed Caffrey
"The Montana Bladesmith"

 

[raker]

For quenching my 52100 and other carbon steels, I use Dextron II that is heated to about 250 to 300 deg. in an electric skillet. After quenching, I leave in the fluid for about 30 min. and unplug the skillet. After about another 15 min. I will take out, cool off, and wash with soap. One of the blades will get the black ground off so I can see the color when I temper. I put in the oven at 375 deg.(for small 5160 blade) to 475 deg. (large 52100 blade) for 2 hours. I room cool and repeat at identical temp. for another two hours. At 375 deg. the blade will be light gold and at 475 deg. it will be dark blue. Most blades are 90% ground when heat treated except for the small blades. Heat control is harder on the smaller blades. Ray Kirk
www.tah-usa.net/raker