Liq. N2...so what if I.....?

Here is a question for you guys!

What, if any effect would placing an old (late1800's) razor in liquid nitrogen do? Would it help the hardness, would I risk cracking the blade, just make the blade VERY cold, etc...?

Also, if I were to try this would you recommend a slow progression to the temperature differences and then a slow progression out?
(e.g. 4 C, -20 C, -80 C, -140 C, Lq N2, -140 C, -80 C, -20 C, 4 C, Rt)

I'm not too familiar with cryo-tempering of metal and am thinking of 'tinkering' with a blade I have been putting 'through the ringer'......

C utz

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Originally Posted by C utz

Here is a question for you guys!

What, if any effect would placing an old (late1800's) razor in liquid nitrogen do? Would it help the hardness, would I risk cracking the blade, just make the blade VERY cold, etc...?

Also, if I were to try this would you recommend a slow progression to the temperature differences and then a slow progression out?
(e.g. 4 C, -20 C, -80 C, -140 C, Lq N2, -140 C, -80 C, -20 C, 4 C, Rt)

I'm not too familiar with cryo-tempering of metal and am thinking of 'tinkering' with a blade I have been putting 'through the ringer'......

C utz

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How come I never have cool stuff like liquid nitorgen just layin around??? I have to reevaluate my stockpile :D

Liquid nitrogen improves gun barrels, which have already been forged/heat treated, so I see no reason it wouldn't improve a razor. I think the effect would be less, however, than if it had happened at the time of heat treat. Paul Bos, who does the ht on my knives, cryogenically treats them immediately after quenching, to help with the tranformation of retained austenite. The resulting blade displays finer grain structure, greater flexibility, improved edge holding, and ease of sharpening. Still, if it doesn't crack the blade, you should notice improvement. One thing, though, is that it would be better to gradually lower the temperature than to just quickly submerge the blade, to reduce the stresses on the steel.

Joes forgetting all the other cool stuff liquid nitrogen is good for, for instance...if you dip a banana into liquid nitrogen...out comes a hammer :) Its also great for quickly freezing chocolate bars as well :D

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Originally Posted by JLStorm

Joes forgetting all the other cool stuff liquid nitrogen is good for, for instance...if you dip a banana into liquid nitrogen...out comes a hammer :) Its also great for quickly freezing chocolate bars as well :D

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:roflmao :cen :roflmao Oh yeah, Josh...supposedly, liquid nitrogen will make your pantyhose last longer, too, with fewer runs. :D

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Originally Posted by Joe Chandler

:roflmao :cen :roflmao Oh yeah, Josh...supposedly, liquid nitrogen will make your pantyhose last longer, too, with fewer runs. :D

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I'll have to try that lol :D Ya think I can justify the purchase to my wife if I tell her about the panyhose thing??

It should be good for wart removal as well :cool:

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Originally Posted by Joe Chandler

Liquid nitrogen improves gun barrels, which have already been forged/heat treated, so I see no reason it wouldn't improve a razor. I think the effect would be less, however, than if it had happened at the time of heat treat. Paul Bos, who does the ht on my knives, cryogenically treats them immediately after quenching, to help with the tranformation of retained austenite. The resulting blade displays finer grain structure, greater flexibility, improved edge holding, and ease of sharpening. Still, if it doesn't crack the blade, you should notice improvement. One thing, though, is that it would be better to gradually lower the temperature than to just quickly submerge the blade, to reduce the stresses on the steel.

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Well, I know what side project I'll be trying this weekend ;)
(and it's not the pantyhose thing....maybe next weekend! :p)

C utz

I doubt it would have any real disasterous effect, but I would use a cheaper blade, just in case.

BTW, LiNi is too fun to play with too. One day, one of my profs brought in some and used it to demonstrate some of the properties of superconductors to us. If you cool certain ceramic materials to LiNi temperatures, they become superconductive; and, as a superconductor, have very neat electromagnetic properties. The exact type of properties that let you float a magnet above one of these superconductive discs, and it just stays there, floating in mid air, with no power. One of the coolest things I've seen.

It was also funny seening him precariously pour the stuff from a 20 or so litre jug into a 1 inch deep styrofoam coffee cup. He pretends to accidentally spill a whole bunch with a dozen people sitting around the table. Never before have I seen anyone jump back so fast. Too funny :)

Whoa there folks.

LN is fun to play with. Okay I'll give everyone that.

LN, despite clever advertising, has not been shown to improve plain carbon steels that were originally heat treated correctly.

LN, can improve the conversion of retained austenite in high alloy steels, meaning those that contain chrome, moly, etc. Stainless steels and gun barrel alloys fall into this category.

There is a lot of hype and flat out conflict of interest out there. The folks hyping the research are the very same people interested in selling you the equipment to do this with. That makes me very cautious.

I have a great respect for Paul Bos. He's heat treated some of my blades in the past. But about all he works with is high alloy steels and his LN regimen is exactly as it should be.

Here's a link to the fellow who should know something about the subject. He describes using cold treatment on steel in one of the middle chapters. What is notably absent is any discussion of using cold treatment on plain carbon steel.

http://mse.iastate.edu/fileadmin/www...hoeven/7-5.pdf

If you put a blade into a LN system, remember that the blade now has untempered martensite in it and MUST be tempered again after such treatments. Otherwise you have brittle martensite. As if razors aren't brittle enough already.

Just want to slow down the stagecoach before somebody has to pull too hard on the reins...

Ed Fowler did a few experiments with LN on carbon steel (particularly 52100, which is about the only steel he works with), and his tests indicated improvement. Now, 52100, because of its higher alloy content, may be classified more as bearing steel, or non-stainless tool steel, so I guess I'm reinforcing your point. :D I believe in his experiment, though, he LN treated a tempered blade, then re-tempered after LN, and noted a marked improvement in both ease of sharpening and flexibility. Ed typically uses a triple quench, triple temper process, and gets more out of 52100 than anyone else I can think of. He has perfected his ht process for the way he makes knives. I would assume a maker using 52100 for razors could duplicate his results.:shrug:

I have no problem with 52100 except that she is a fickle mistress. If you're not paying attention, that steel can and will get away from you and turn a good knife into a piece of junk as the price for inattention.

I'm pretty simple. If the knife improves as a result of LN, then retained austenite is being converted to martensite. That could mean a bad heat treatment regimen up front (carbon steels) or the steel does require that help (high alloy). Some of the new CPM alloys will have up to 25% retained austenite no matter how you treat them even with LN.

I know some factory tool and die guys (69 yrs experience together) who could argue the economy of LN treatments too. They know sharpening the high alloy steel tools really well and their comments are that for the most part it costs more money and does not produce enough improvement in the tooling performance to justify the cost.

What I can't abide is makers rushing like lemmings after a process to make their blades better when it may not make practical sense and old methods work just fine. As long as it's done right in the end I wont' have much to say. And, folks can really do whatever they want to blades whether I have an opinion or not.