Hi guys,

I have some issues regarding the steel behaviour in unusual temperature environments.
This is something I searched for, but haven't found yet on any forum until now.

Which is the maximum temperature on which these steels can be exposed without being dequenched and loose the properties they obtained during the complex heat treatment?
What happens with my knife if I drop it by mistake in a pot of boiling soup (this means about 100 degrees Celsius)?
What if I use the knife tip to mingle some potatoes frying in sunflower oil (this means about 300 degrees Celsius)?
What happens if I let my knife on the sand on the beach exposed to the sun all day long during a canicular summer day? (I don't know exactly what temperature the knife can reach in this case, but it will obviously get extremely hot).

What should normally happen with my knife properties (hardness, lateral strength, edge retention, shock rezistence etc etc etc) in the above particular cases? Will it loose its hardness?

I'm also interested in what happens if my knife is used in sub-zero environments. For example, let's say it will chop frozen flash or wood at 30 degrees under zero. Will INFI be chipable or breakable at that temperature?

I'm currently an INFI only user, but I consider achieving some SwampRat and ScrapYard knives in the future too.

I think Jerry or Dan Busse may give the most appropriate answer to this, but there may be others who know something.

I'm really interested in this regards. Many thanks to anybody who can tell me anything!

Best Regards!

i would use your body heat to warm the steel up if where too cold because all steel becomes brittle if it gets cold enough.

as far as heat is concerned just dont let it get to hot.i dont think the sun under normal conditions will get it hot enough.jerry has said INFI would have to reach up to 900 degrees to ruin its temper.i'm sure SR77 & SR101 temps would be lower.

if you dropped it in boiling water it would be fine if you took it right out.if you left it in there for a while you may run into a problem.

while i'm sure there are technical answers that only someone like dan or jerry could answer some of it is common sense.

out5 - Howdy and Welcome to the ScrapYard! <img src="/ubbthreads/images/graemlins/thumbup.gif" alt="" />As Dave suggested, Dan or Jerry could probably be the ones to answer your questions. I don't think that most of us will ever "take our knives to the limit", but they are covered by the best warranty in the business so don't be afraid to use them. I just don't advocate deliberate abuse. <img src="/ubbthreads/images/graemlins/crazy.gif" alt="" /> <img src="/ubbthreads/images/graemlins/grin.gif" alt="" /> Tom

With Scrap Yard (and old-school Rats) I suspect that you'll be OK as long as the knife doesn't get hot enough to melt the ResC handle. Of course, when talking about localized heating, like on a grinder or belt sander, that rule won't apply. A little surface rust would be the only result I might expect if you left a Scrap Yard out all day on the beach.

Good question alot of people use their blades to do the prep work and then the cooking. Not sure how many will have a frier in the bush, but hey you might be able to fry some roots or small peices of meat in fat. Again a really good question.

Unless you leave the tip laying in the food you're frying for an extended time, the blade shouldn't get terribly hot. Really, what I've heard is that so long as you don't let a blade get hot enough to change color, you shouldn't have any issues. As a rule of thumb when using a sander/grinder, you don't want to let the blade get too hot to touch, but that's because localized heating at the point of contact will be much hotter than the blade as heat is dispersed by conducting into the surrounding steel.

This isn't you?: http://www.youtube.com/user/out5yder

Good God man <img src="/ubbthreads/images/graemlins/ooo.gif" alt="" /> <img src="/ubbthreads/images/graemlins/ooo.gif" alt="" /> <img src="/ubbthreads/images/graemlins/ooo.gif" alt="" />!!!! Please tell me this is a typo. That's about 570 degrees fahrenheit and almost to the flash point of the oil. Let's try to keep those frying in oil temps between 165-210 degrees Celsius. <img src="/ubbthreads/images/graemlins/smile.gif" alt="" />

S7 the base for SR77 is used in hot working applications up to ~ 1000 degrees Fahrenheit. So SR77 is probably in the same ball park. The RES C handle will turn into goo and disappear long before that <img src="/ubbthreads/images/graemlins/ooo.gif" alt="" /> <img src="/ubbthreads/images/graemlins/ooo.gif" alt="" />.


Cooking potatoes at 300C <img src="/ubbthreads/images/graemlins/ooo.gif" alt="" /> <img src="/ubbthreads/images/graemlins/ooo.gif" alt="" /> are you in a hurry....LOL better have a fire extinguisher handy <img src="/ubbthreads/images/graemlins/ooo.gif" alt="" />

Yes, Momaw, that's me on youtube. I have many many knives, but when I said "an INFI only user" I actually intended to say I don't have any SR-77 or SR-101 yet (these 3 steels are targeted by this topic).

Please, don't think I always push the limits of my knives like that, but anytime I buy a new knife which I intend to count on during my expeditions, I first want to know its limits in all areas so that I know exactly what I should expect from my equipment when I go far away from inhabited areas alone. In this way I also get familiar with the tool, start understanding it and so on. Most of the time I go there alone. And I never go there with new or unused (by myself) equipment items. I also don't consider enough to test a knife and get with me a new one of the same model! I simply want to test exactly the individual knife that I will take with me to be sure I know exactly how it behaves.

When you don't know the limits of your equipment, you can't achieve the maximum possible from it. Sometimes you take exagerate care which leads to loosing a lot of time in the field, othertimes you may abuse the equipment too hard which may lead to remaining without it when you need it mostly.

Of course, I do not intend to make a tasteful soup of micarta and drink it, but I have to know the limits of the steel in order to know which situations represent danger for the knife and which not.

Regarding sub-zero temperatures, I found at this link: http://www.dfoggknives.com/heat_treating2.htm some things about someone who needed a knife to chop frozen meat at 80F below and the only knife which rezisted was a custom L-6 steel knife. In my case, the hot temperatures can be encountered at some point, but the cold have never reached less than 25 degrees Celsius below zero in my country. So, I'm not too concerned about that. Just curious. But I was just wondering... how would INFI behave below zero Celsius and at which point does it became chipable/breakable. Logically, the nitrogen should make INFI blades to freeze faster than other steels.

I'll be out testing my Skinny ASH-1 this weekend. Thank you all for replys. I'm still waiting for Dan or Jerry to reply at some time to this topic.

Best Regards!

I can personally vouch for SR77 & INFI working just fine at temperatures below -40. Depending on what winter serves me up this year, I'll try and make a point of testing far below that. It does get hard though as breathing at temperatures around -80 gets annoying! <img src="/ubbthreads/images/graemlins/tongue.gif" alt="" />

-80 now that is cold!
We get to -50celsius pretty much every winter and I have been out on the sleds at that temp and it is hard to see because your eye moisture freezes.
I have heard of some knives breaking much easier at '40 or lower and there are special steels used for building in the north.

From what little I know about steel I would guess that Sr77 would be better for cold temps than most steels. High hardness steels with very high edge retention
like ZDP189 would be especially bad.

I do know Res-C handles are especially good for cold temps.