Triple quench secrets to be revealed?(or not)

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Tuomo, my compliments on a most excellent post! This is very interesting for me, a fellow that sends his blades out for HT because of $ for new equipment and space. I want to also let our fellow makers know that you are by my standards an expert in knowledge of your country's knives and how they are PROPERLY ground, also. Since polar bears are pretty scarce here, I am still having to send out my blades for HT. Also, Dave will have his salt bath if I can get far enough from the homestead to drop off the stainless pipes that are loafing in my shop.
 
Thanks Jonh! Always seeing somebody on slippery ice needing a friend!

Finland is the best place to make knifes. We get this fasionable freezing for free.
One time I did forget my liquid nitrogen freezing tank outside and was unable to sink my knife because the nitrogen was frozen.

By the way Fnnish "outdoor frozen" knifes bite worse than a polar bear ever. Once I was even able to cut a cake baked by my wife.

You are very active with your projects and making something useful (, I see on the forum). I am just causing nuisance and talking.


pig or Tuomo
 
Originally posted by pig

Finland is the best place to make knifes. We get this fasionable freezing for free.
One time I did forget my liquid nitrogen freezing tank outside and was unable to sink my knife because the nitrogen was frozen.

By the way Fnnish "outdoor frozen" knifes bite worse than a polar bear ever. Once I was even able to cut a cake baked by my wife.
pig or Tuomo
Click to expand...

:D :D :D
 
Tuomo Pig, You're right about outdoors in the cold .We heat treated some air hardening tool steel and put it outside to quench.We used that hardness in our specs, customers could not understand why they couldn't get the same hardness !! Back to the question. When I ( and others ) are asked to recommend knife steels for the beginner with simple shop my answer is 5160 for impact use ( sword, kukri ) and 1095 for better edge use. They are easy to forge and heat treat. BUT when I see triple quench that's no longer simple. So I take option #1 - I think a proper single quench will do at least as well as a triple quench with 5160. It would be nice if someone would conduct tests with steel heat treated under very carefully controlled time and temperature, let's be scientific . Did you see the story about the purple polar bear ? In a zoo in Argentina a bear had a skin problem so they painted him with a purple chemical to treat his skin. He became a celebrity ! The color will wash off. For D.Forge ,for you're needs maybe you should buy a Camillus BK7 which has a great reputation for very tough and holding an edge very well it's made of 50100B. I wonder what the Finns call a polar bear.
 
Mete thank you,
this was I hoped for!

You see, I am not a metallurgist (meanig my words are not important until I am a "smith celebrity"), smiths on other hand are doubtful and on the other hand respect metallurgists, so the word of a metallurgist is imortant admitted or not. (Many pretend, it is not important.)

Once more, you had an important and great benefit to black smith community.


pig
 
Someone here mentioned it may be helpful if a controlled test were performed. 'Controlled' may be more than my equipment but I have a Even Heat digital controlled oven. The only oil quench steel I have on hand is O1. I could take some samples from the same bar stock. I also have Rockwell testers and they are calibrated to test blocks.

So, let me know?? RL
 
DaQo'tah Forge,

You outlined in an earlier post in this thread the process you use for heat treating as told to you by Ed Fowler. To boil it down you put the knife threw several thermal cycles and then quenched and tempered. You then said it made a great knife. You did not mention triple quenching. Did you leave that part out or did Ed not tell you to do it.

This is not an attempt to catch you at anything. I am wondering if Ed is now just using thermal cycling to achieve the results he had been using triple quenching for before.


itrade,
If Schroedinger had two identical cats running in opposite directions and he shaved one, would the other cat have hair?


Seth
 
Seth....I would have to find the post you are looking at,,however you may have caught me forgetting to list the 3 actuall heat treatments,,,I will drop back to see..

But yes, after i have forged and used my belt grinder to get the cutting edge about as thick as a 1/16 of a inch or near that,,,I then heat treat 3 times, with 24 hours between each time, then I temper in an oven at 350 for 2 hours, I do that 3 times to with 24 hours between each time..
 
Seth


I droped back to the page before this one on this topic, and YES, I forgot to list correctly what Ed taught me to do,,,,However if you just glance up to my first post on that same page 3 of this topic it is there that i do try to make clear that I heat treat 3 different times...

but you are correct to point out that i did not list Ed's advice to me in the correct manner, and yes, my words could give the wrong idea about what i'm up to...actually the time between my first post on page 3 and my 2nd was when I was getting the advice from Ed. The moment I got the email from ed I ran out and fired up my forge and unwrapped a section of 5160 steel I had been sitting on waiteing to try Ed's ideas on...I forged a knife with his new advice for me that very night,,,
(in my defence I would say that the sun was in my eyes when I wrote that other post that has the error,,,or, perhaps the GUINNESS was just kicking in?)
 
rlinger, If you would like to do an experiment I suggest the following. I assume O1 , 1/8" stock so 2 - 1"x1"pieces . Sample #1 - single quench - set furnace to1450F, bring sample to temperature ( you'll have to do this by color),time 5 minutes, quench in warm oil temper immediately 400F 1 hour. Sample #2 - bring sample to temperature, quench in warm oil, temper immediately 400F 1 hour.Repeat this 2 more times . ( don't wait 24 hours between sinc I have absolutly no idea what that is supposed to do) Measure hardness. Thanks
 
I think an important thing to consider here is the reduction in grain size which appears to be a result of the multiple quenching. Heck, even Kevin Cashen will tell you to throw a few quenches into your thermal cycling sequences to improve the steels performance (this may have been for a specific steel like L6 however, I can't lay my hands on the post from Swordforums I printed out concerning this). As I understand it the carbides formed in the initial quench, pin the grain growth in subsequent quenches resulting in a super fine grain by the third quench. The results of this apparently taper off to negligible returns after the third quench. Increasing the soak time would dissolve most of these "pinning" carbides and result in an as quenched the first time grain size. Am I off base here?

Kevin also marquenches most of his blades now. I've often wondered how a marquenched blade made from 52100 would perform.
 
mete, I can do all as you say with these exceptions: My O1 is 9/64 (1/64th thicker), my narrowest stock is 1 1/4 (1/4 wider), I have no quartz window to view color. I can say this: all samplings will be consistant.

I am pleased you gave me specs to go by. This eliminates the operator from deciding his own specs.

The temper immediately (relative) is second nature for me, so no problem there. However, I need to ask - at what point should I pull the steel from quench and how low in temperature should I allow the steel to become before placing in the pre-heated temper oven??

If I have neglected to ask anything else please advise.

RL
 
rlinger, cool the steel to the oil temperature then temper. I would also like to get an idea of the grain size so you should fracture them after measuring hardness, it might be easier to grind notches before trying to fracture. --- Silent , There are very recent comments about triple quench in swordforum between H Clark ,K Cashen and myself. The emphasis is that it was done under laboratory conditions !! not heat by torch and temperature by eye !!
 
Thanks Mete, life hasn't given me as much time lately to keep up with things. I'll definitely have to pop over to SF and catch up. Can you tell me who started the thread there and about when and was it in the Bladesmith's Cafe?
 
mete, I read you load and clear. Can't start til Saturday or late tomorrow evening. On the road tomorrow til early evening. Too late tonight.

How am I going to give you, or anybody, grain structure?? Will my digital shoot it well enough for posting??

RL
 
It is awesome that rlinger is willing to try this out for all of our benifit. Thanks. I think the steel is wrong however. It is the chromium steels, 5160 and 52100, that triple quenching is suppossed to help, not O1.

I will be glad to send someone 5160 if needed to see this done under the right conditions.

Seth
 
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