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Blade elasticity.

skimo

January 22, 2013 08:14

So, one of my main concerns with any blade, living in Alaska is how metal acts at low temperatures, I've heard that blades can lose their plasticity at temperatures as high as ~70F.

For a while there was word of some fixed blades that failed in cold climates.

So testing in temperatures at least to -55F would be nice.

Comments

23 comments

dj

January 22, 2013 13:45
quote:

So testing in temperatures at least to -55F would be nice.

Do I understand this correctly ?? Minus 55 degrees below Zero ??
Who in there right mind would even be out side in weather like that ......LOL
I suppose there are some that might have to go out in weather like that , but surely not to skin a deer.
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timmy3bm

January 22, 2013 18:14
New Year's Eve of 2008 I was in wasilla Alaska outside lighting fireworks for a good 45 min. With the wind chill it was -65f!!!!!
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skimo

January 22, 2013 22:10
Skin deer no, strip wire, chip ice.... -55 isn't too cold, up North it gets colder.
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deathofallthings

January 22, 2013 22:57
So you're from balmy south Alaska?
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David Lerman Contractor

January 23, 2013 01:11
At 55 below I dont need a knife..I need a heater
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different

January 23, 2013 01:32
I've never had to work in those type of temperatures but have had to work outside when it was -20. When you're out working on a burst water line or some such thing and it's -20, the last thing you want is your tools to break.
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skimo

January 23, 2013 05:19
quote:

Originally posted by DeathOfAllThings:
So you're from balmy south Alaska?

Central, but now in southern.
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sharpener1969

January 23, 2013 13:51
I would learn about the characteristics of metals at sub zero temperatures. Find a blade steel containing alloys that make it tough at those temps . You may not be able to have brand loyalty but if failure is your main concern . Who cares. Especially if your life depends on it. Waiting for Benchmade to do testing at sub zero temps I highly doubt. They would most likely use metals that have already been studied if they wanted to have a niche market Artic Knife. Same knife in say 70F may not perform as well as common blade steels. It is interesting. If I ever get a dewar I have some saw plate with high nickel content. Heat treat and temper . Then cool to desired temp and take out and test. maybe a damascus would be a good blade steel with mild steel and high nickel. if it shattered the nickel might keep it together. I don't know but like I said . I find it a cool question.
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vance

January 24, 2013 18:11
We reviewed this with the metallurgists at Crucible and they confirmed steel would indeed be slightly more brittle at -50 degrees and below. However, there are too many variables to provide an exact percentage of increased brittleness at those temperatures (alloying elements; grain structure; heat treatment; geometry, etc.).

Now we’re intrigued. Pete’s already working on ideas on how we can test this. Stay tuned…
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skimo

January 24, 2013 21:27
Awesome!
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grampa

January 25, 2013 04:26
About thirty years ago, when we lived in Canada's Northwest Territories, there were a couple days one winter when it got down to -49C, which is about -56F. That's straight temp, not wind chill. Strangely enough I didn't do much outside except for getting more wood for the stove! Forgot to spend an hour or two out whittling to test blade steel response to cold temps!
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sharpener1969

January 25, 2013 17:13
I personally would like to try H1 and not for subzero uses but it could have its advantages in the super cold. Work hardens. From what I have read crucible did hardness test with it and found it measured up to 68 HRC on the edge and 58 on the spine. It is also said to deform rather than break. nickel content 6-8% . crucible has similiar precipitation hardening stainless steels but not manufactured as blade steels. Wonder what their thoughts are on H1.
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thepunisher

January 26, 2013 19:09
a blade will snap at temps like that.

look into youtube a few vids on knives getting brittle and breaking.
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theblueram234

January 27, 2013 07:24
would this be one of those times that an M4 Blade with a Rockwell down around 58-60 would or may become hard in a sense of where we wish it would be at 70 degrees fahrenheit with a 62-64 rockwell . or would it just brittle up and chip? regardless of the rockwell it has?
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skimo

January 27, 2013 10:33
Good question for the metallurgists and testers.

I'll test blades up here up in the toolies every winter if you guys want
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mcm

January 29, 2013 10:06
Vance, time to break out the liquid nitrogen
and have some fun! (Dont ask me how I know)
LOL LOL
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theblueram234

January 31, 2013 07:19
quote:

Originally posted by Skimo:
Good question for the metallurgists and testers.

I'll test blades up here up in the toolies every winter if you guys want

If you need a base line in the mid 70-80's
I'd be happy to forward my findings and the knives to Skimo for the sub-zero testing
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peter

February 01, 2013 15:42
Currently we don't have a good "in house" method for cryo-treatment of the blades down to sub zero temps.Or a solid means to measure core temperatures. It seems that this one will take a bit more time and effort to do correctly. That being said I still wanted to do a simple small scale test. Found six extra 580 Barrage blades (154CM)in my testing bins. So we took two blades at room temperature, put two blades in a freezer overnight, and buried two blades in a cooler of dry ice overnight. After performing our standard tip break test there was no notable difference in the amount of force required to break the blades. I'm not satisfied with these results, so I've been in contact with a local third party testing company and we discussed their ability to perform sub zero fracture patterns for our blades. Hopefully we will be able to see a more significant result. More to come...
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trailboss

February 01, 2013 15:58
quote:

Originally posted by Peter:
... After performing our standard tip break test ...

Peter, what is your standard tip break test? I'd like to see some vids of that too.
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peter

February 01, 2013 16:22
quote:

Originally posted by Trailboss:

quote:

Originally posted by Peter:
... After performing our standard tip break test ...

Peter, what is your standard tip break test? I'd like to see some vids of that too.

The standard tip break test is featured in the next video I'll be posting. I wanted to see what it would take to snap the tip off of a 162 Bushcrafter. It wasn't easy, lol. Basically we have the ability to wedge a blade tip up to 0.600" deep in a machined steel fixture, then apply a constant side load using a Chatillon digital force tester. It pushes until the blade breaks and records the amount of force and distance travelled up to and including the moment of fracture.
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theblueram234

February 01, 2013 16:26
thought this video was pretty cool
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trailboss

February 01, 2013 16:29
Cool!

It would be interesting to see a Rift or a Contego tested to see how they fare against a more blade shape.

hint, hint.
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minkeyman

February 05, 2013 17:27
I think seeing the Rift and Contego would be awesome too.

If I wasn't too busy right now I could refresh my memory from my metallurgy minor and talk in more detail about brittleness at cold temps. Already have a full plate for the time being though. Sorry guys. Maybe soon I'll have some spare time to give some info for yall.
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