Water Quenching vs. Air Cooling between Tempering cycles?

C

coldsteelburns

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This has been on my mind for quite a while now but I never really figured it was important enough to really ask about. The thing is, it seems like most people air cool between their tempering cycles, like from when I read WIPs etc. etc. However, I have heard at least a few say that they (as well as suggest it be done this way) quench the blade in water between cycles, Mr. Apelt (Stacy) is one who comes to mind. So can anybody tell me if there are any metallurgical changes that can occur by doing either method between tempering cycles in the ~400-450*F range and if so what would they would be affecting?

It guessing many people might just do it whichever way "they" happened to be taught or read about when first starting out, without any researching the differences. Also, I believe a good amount of people who quench (or rinse under runnng water) might just be doing it that way to save time in order to start the next cycle right away. But! I have heard the quenching in water, (or was it rinsing under a water faucet?) "stressed" by Stacy. (BTW Sorry Stacy, I'm not trying to single you out, your just the only one that comes to mind at the moment regarding this. :o Also, sorry If I'm misrepresenting what you have said, if I am, please correct me! :foot: ) Thanks guys :)

~Paul
My YT Channel Lsubslimed
 
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Rinsing in running water if not done evenly may warp the blade .
Quenching between tempers saves time but also prevents some stabilizing of the austenite , preventing further tempering.
 
Rinsing a blade from 400F in running water won't warp or damage the blade.

I have done hundreds that way, and industry has done millions. Warp happens as the metal changes phase in the quench from austenite to martensite.
Tempering is all martensite, so there is no phase change on cooling.

As pointed out, the reason to cool more rapidly is to avoid stabilizing of RA and a few other minor metallurgical things.


It won't make a huge difference in whichever way you do it - fast or slow - , but metallurgically, moderately rapid cooling from temper is better.
 
I do a full quench in my quench oil right out of the oven.
Clean oil off in detergent and right back in for second temper.
The oven is hot, and I need to get some knives done.
 
What you quench in really doesn't matter. If the oil quench tank is what is close at hand, that is fine. I have a sink next to where I temper most blades ( kitchen oven), so I use water.
 
That's exactly what I was looking for. I'll continue to quench between cycles, and get those two birds (even if they are somewhat small) with one stone while I'm at it.. :D Thanks a bunch fellas! :)

~Paul
My YT Channel Lsubslimed
 
Since this thread is being mentioned elsewhere now, maybe a clarification is in order. No one hear is saying that you have to quench in water to during tempering, or that it gives a performance increase. I do quench in water between tempering cycles, because for no other reason I like to see the tempering color. Once the blade is quenched and is at Mf, it goes into first low temp temper. Then it gets a water quench, in order to cool it down in a hurry, so that I can grab a hold of it and sand off the scale that formed during hardening. Then back in at a higher target temp twice, water quench in between, just so it is easier to hold onto.

There MAY be some carbide precipitating during this quench during tempers, but I don't think anyone is saying "Absolutely, you should be doing this for performance reasons."

For me, it is more about convenience and speed. Nothing more.
 
"For me, it is more about convenience and speed"

That is most of the reason. It saves time....which is the same as saving money. Any metallurgical benefit is a bonus.
 
I do kind of a lot of thin knives, and have yet to see one warp from quenching with a cool water spray between tempering cycles.
 
samuraistuart said:
Since this thread is being mentioned elsewhere now, maybe a clarification is in order. No one hear is saying that you have to quench in water to during tempering, or that it gives a performance increase.
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uh oh, what kind a trouble did I start this time :foot: lol But really though, where else is this being talked about? And I agree with you and Stacy, since it can't hurt, and it "might" possibly make some difference metallugically, even if it's a only tiny bit, plus it speeds things up, I see no reason not to quench between cycles.

~Paul
My YT Channel Lsubslimed
 
What Stuart was saying is that there is no magical property or great improvement from the procedure.

It is efficient and saves time. It also aids in conversion of RA into martensite, which will be tempered in the second temper. The longer the time it sits as RA the less will convert to Martensite. The RA is a very small amount in the first place, and the difference would matter only to a metallurgist. A knife made either way would be equally hard and tough by any method of testing the average maker has.
 
I didnt' want to mention it here, but since you asked, Paul, it was brought up on Fowler's Knife talk forum. I can see the "temper water quench" thing spinning way out of control over there, just wanted to nip it in the bud so to speak.
 
samuraistuart said:
I didnt' want to mention it here, but since you asked, Paul, it was brought up on Fowler's Knife talk forum. I can see the "temper water quench" thing spinning way out of control over there, just wanted to nip it in the bud so to speak.
Click to expand...

I just searched that out... Thanks a lot, Stu.:mad:

I agree that the metallurgical benefit is negligible. What I was unaware of, is that if you then deem it as merely a "time saver", I has a negative effect on the quality of your blades. No fooling... Once mentioned, it is too late... your product is inferior. The only solution is to allow it to cool naturally(and with proper reverence) over a 24hr period, for each cycle. Makes sense, doesn't it?

I'll bet you "Time-Savers" didn't count on that alternate bit of reality.:eek: It's all coming out in the book of the eternal future.
 
samuraistuart said:
I didnt' want to mention it here, but since you asked, Paul, it was brought up on Fowler's Knife talk forum. I can see the "temper water quench" thing spinning way out of control over there, just wanted to nip it in the bud so to speak.
Click to expand...

Rick Marchand said:
I just searched that out... Thanks a lot, Stu.:mad:

I agree that the metallurgical benefit is negligible. What I was unaware of, is that if you then deem it as merely a "time saver", I has a negative effect on the quality of your blades. No fooling... Once mentioned, it is too late... your product is inferior. The only solution is to allow it to cool naturally(and with proper reverence) over a 24hr period, for each cycle. Makes sense, doesn't it?
Click to expand...

Go Figure! :confused: :D I think they are taking out of context the fact that the "time saver" aspect is just another added bonus in the same way that the teeny weeny bit of RA conversion would be. Sounds as if somebody over there looked at this thread and perhaps thought they read something like, "I only temper my blades for 30 minutes instead of 2 hours per cycle, since it saves me time, and time is money! GAARR!!!" :emot-yarr: lol And I know that is certainly not the attitude of anybody who has commented here... But anyway, I appreciate you allowing me to get my curiosity fix Stu, thanks man. ;)

I'll bet you "Time-Savers" didn't count on that alternate bit of reality. :eek: It's all coming out in the book of the eternal future.
Click to expand...

LOL too funny brother :D

~Paul
My YT Channel Lsubslimed
 
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Or, " I use lawn mower blades because they save me money. And, I don't do HT because it saves me time. My knives still get hair shaving sharp!"
 
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