3V and cryo revisited...

mete said:
Data sheets are on the new website . www.crucible.com
They may not be 'complete' but remember those instructions are for typical use which may not include knives !
Click to expand...

Thanks Mete

Looks like the same sheets. Is there anywhere that someone can see a "complete" sheet or HT table for 3V? I can't imagine this 400 degree temper is just anecdotal.. :confused:

Rob!
 
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For the most part tempering of steels starts at 400 F then goes up to about 1000 F .If we want max hardness and strength of the steel we temper at 400 F. That's where it comes from. You can experiment with various temperatures and check hardness , toughness in actual use and pick the numbers that are best for you.
Properties that may be of interest to a tool and die maker include long term dimensional stability and holding hardness at high temperature [secondary hardening] which are of no concern to knife makers. Knife makers then look for typical knife needs even if they ignore typical tables to do so.
 
Are we talking about steel or global warming. Perspectives, attitidues, available data and proponent/opponent passions are similar... :)

3V is great steel, heat treated just as God and Crucible intended it be.
 
Jerry Hossom said:
Are we talking about steel or global warming. Perspectives, attitidues, available data and proponent/opponent passions are similar... :)

3V is great steel, heat treated just as God and Crucible intended it be.
Click to expand...

:D OK Jerry. We know how Crucible intended. Give us the word of God.

( I knew you had to have some help to turn out such incredible blades. All this time I thought it was Tom's mentoring.)

Rob!
 
Paul Bos does 3V this way, IIRC.

Harden at 1975F
Forced Air Quench (something like that anyway)
Snap Temper for 30 minutes at 375F
Overnight in LiN
Double Temper at 950F for 2 hours each
Straighten all of Jerry's *#^&% bent and twisted tangs
Ship to Georgia.

Rc60/61

Frankly, I have to wonder if you can get Rc61 without some secondary hardening. Even then the above HT results in a steel with ~1 micron grain size. Pretty fine stuff.
 
Jerry, at 950 F temper there shouldn't be much retained austenite left even without cryo.Do you have any figures on this ?
 
Cryo then temper at 950? Where does the edge stability go? That recipe kinda contradicts what we talked about earlier in this thread. I am a hair confused. Does the cryo help with the edge stability when using the high temper?
 
There isn't much retained austenite in 3V so it probably benefits less from cryo than other steels. Cryo's a little bit like chicken soup..., can't hurt. :)

Edited to add: I have over 10 years experience with 3V using this heat treat schedule. In that time I've seen the steel perform spectacularly well in virtually every challenge, including those where the objective was to actually break the blade. Whether cryo's needed or not, I'm not changing a thing.
 
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Just got this response back from SBSM (formerly Crucible Service Centres), in response to my question about a 400 degree tempering range for CPM 3V.

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HI Rob,

I just spoke to Scott Devanna and this is nothing that he has heard of!

He said that tempering 3v at this range could make the material very Brittle!
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Not suggesting this is necessarily correct, but adding one more respected opinion to the discussion.

FWIW

Rob!
 
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if my HT is thought to be brittle then i surly would have to change steels to get something strounger (like S7 :) )
i ll have ot see what all testing i can do and see how it favors the high temp HT in a side by side

i am now interested in more info other then jsut what i have beat on my 3v stuff
KnifeMaker.ca said:
Just got this response back from SBSM (formerly Crucible Service Centres), in response to my question about a 400 degree tempering range for 3V.

-------------------------------------------
HI Rob,

I just spoke to Scott Devanna and this is nothing that he has heard of!

He said that tempering 3v at this range could make the material very Brittle!
-------------------------------------------------------

Not suggesting this is necessarily correct, but adding one more respected opinion to the discussion.

FWIW

Rob!
Click to expand...
 
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Aargh! Note my edit two posts back. I was referring to CPM 3V. I have no idea how S30V got from fingers to the keyboard. :o

It was 3V I was asking about and 3V that was responded about. Sorry for any confusion.

Rob!
 
butcher_block said:
if my HT is thought to be brittle then i surly would have to change steels to get something strounger (like S7 :) )
i ll have ot see what all testing i can do and see how it favors the high temp HT in a side by side

i am now interested in more info other then jsut what i have beat on my 3v stuff
Click to expand...

I can personally vouch for Butch's 400 degree temper on 3v. I've watched him take a 3v necker that was tempered at 400 and use it as a cold chisel to remove a can from a damascus billet...using a ball pein hammer directly on the spine....nothing on that blade chipped at all.

-d
 
Deker, that's a relief ,I thought I 'd have to throw out my Knowles chopper !!
 
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