Icing Down a knife, needs suggestions PLEASE

Thats what I was told also, -109. if it helps or not I'm going to find out, its a cheap experiment that could prove beneficial,, if not at least I'll know.

Thanks all,

Bill
 
mete said:
From various sources , - 109.3 F . See www.dryiceinfo.com ,and you can remove gophers with it too !!!
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now we're 10.7 degs less then the recommended low :)
reccommended by Bohler/Uddeholm, Crucible and Timken/Latrobe
if done in conductive liquid like acetone it will be even warmer.. :)

anyway the point was it can be done without dought :)
let us know how it turns out Bill,

but just know it can be better if your not satisfied :thumbup: ;)
 
Crucible calls for dry ice treatment at -100°F. (see data sheet for 154 CM)
Bohler/Uddeholm rates it at -95° to -110°F. (See any data sheet)
 
mete said:
to get significant reduction in retained austenite you need ~ -110 .]
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as Mete said,, which I believe is to say, not full reduction or as low as you can go.
I had -90 in my head for many years now so I don't know which manufacture or who said that now,
but as time changes so does some figures as testing goes on, or it could have been just plain wrong information in the first place with that said...

my point still is , why settle for significant reduction when you can get more reduction by going colder if the cost is close to the same?..
Bohler/Uddeholm strip steel is at a lot lower Rockwell then we look for I'm taking band saw steel,,, thinking in application use alone,
it could be that it's all that they require of their steel..?
just some thoughts here,, valued just under 2 cents in Canadian change :)

just another thought here to kind of confirm what I believe..
there was talk of going with helium right here at one time,, still colder then LN,, so if CO2 was OK why this talk of helium? cost verse gain was the factor with it.. :)
 
I understand what your saying Dan, but the cost of just driving 3 miles,picking up $10 worth of dry ice is a lot less troublesome and inexpensive then buying a dewar and having to drive 30 miles for me to get it filled every time. Especially if the dry ice produces blades of similar result as those used with Nitrogen. Many claim that over night in the home freezer improves their blades, if this is so, then something that cools -100 more should help, but then again maybe not, I don't know yet, but I'm going to find out something this next week.
I think that Nitrogen is used because it is easier to store and keep for a longer peroids then dry ice. Because it goes to a lot lower temp could be just a matter of coincidence. You know there's always over kill with everything, and most of the time there's a limit to what helps, be it -100 or -300. Maybe it will take the -300 of Nitrogen to benefit I don't know. Some will claim a lot of things just because they do it that way, especially if its something strange or out of the ordinary. This is done mostly to get customers to think it must be better, when actually there's no benefit at all, except to sale it.
I have 2 test blades ready to heat treat, so I'll see if the dry ice improves my heat treatment, anyway. If its significant then I might look into a dewar and nitrogen.

Thanks,

Bill
 
Bill,

I bought $14.00 worth of dry ice Friday night and did 4 blades then and 3 more on Saturday and there is still a little left in the bottom of the cooler. It was in the low 90s here yesterday, too.

It depends on who you believe whether the -300+° is better. Mete and most metqallurgists that I have talked to or read about say that you don't gain that much with the lower temperature. The companies in the cryo business claim much greater results, but I haven't seen any independent confirmation of that.
 
Steve, thanks for the info on the ice lasting time. I just took a small cooler and placed 1" construction foam all around the interior, figured that would prolong the ice life some also.
After you do your cyro with the ice did you see any difference in tempering temps needed from those heat treated with out the cyro. Just curious.

Thanks,

Bill
 
Bill, I don't know how well my experience will translate to 52100. I mostly do D2 and some A2 and S30V. For D2 my plan is to get it quenched and as much retained Austenite as possible transformed as fast as possible because of the tendency of D2 to form large carbides. I plate quench and as soon as it gets to room temperature, it goes in between slabs of dry ice. I temper once at 400°F and the second around 425°Fwith the target of ending up just over 60 HRC.

I don't have the lab equipment to test my idea out scientifically, but I get good consistent results that I am happy with. I can get a pretty fine edge on D2 with this treatment-it feels more polished than the usual D2 toothy edge. When I want to make a big chopper or bowie, I usually use A2.
 
Hi Bill
hey it's no problem with me here..and I fully understand putting your toes in first..
we all have our ways and needs to push ahead.. I just mention things here
as food for thought, we've had 450+ lookers so far, so I bring up things for the viewer to contemplate..

the only thing I can say about over kill is if it gets the job done all the way or most the way, cool.. if it's iffy? well personally.. I'd rather go the over kill way :D

I do travel 35 miles one way to get my LN and in my lab dewar 9 pounds will last just about 24 hours..so even that differs with equipment. like I said it's all for information proposes only, not to try and force anything on anyone, I don't yap on here to do that..
hey I got a lot out of this one..as do I on must of them :)
BTW Bill that last write up I saw on you was great, you're doing ok :D
Kim did a great job too..


For everyone that reads the forums..
we all have stages in life with material things..for one man a Pont sunfire is all he wants and needs, for me it's a Bonneville, why? because I've worked
on enough cars to know the pluses with the K body's they are just plain built better.. you'll spend less money in the long run,
but I've limited myself to that car because of my Ideals, as far as cars go.

if a man buys a questionable knife made in China and it's better than he is use to,, hey he's a happy camper and should be.
but we know he could have a better knife. but just how much better.. :confused:

if he believes it's the best because he's had no better knife, then he just limited himself, and that's OK too, but if he boast it to be the best then he does the
knife world,new buyers nor himself any good.
he just needed information to know there are better,,
but just how much better can it get :) a lot I think.. ;) we learn more each day and what we do with that information is up to us.
I'm going on and on again,, right?
 
I'd suggest just calling Bruce or Steve at Crucible. Both would be happy to answer any questions.
 
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