A scientific approach to assess the effect of direct sunlight on INFI heat treatment

[redbeardrob]

900? Wow INFI really is invincible.

 

[Huntsman Knife Co. LLC.]

Serious question, can simple carbon steels like 1095 or 52100 get hot enough from use to harm the HT?

Satin blades get extremely hot when chopping and if you add the extra 150 or so degrees that sunlight adds to the temperature of a blade I sometimes get worried.

I believe SR 101 can be ruined of brought up over 350 degrees. While chopping on a sunny day for about 10 min my Rat Daddy LE got so hot I could barely touch the blade. I'm guessing around 180 degrees as any prolonged touch would have given me a burn.

Is it possible to ruin a simple carbon steel chopper just with sunlight and the friction produced from choppong?

 

[teclis22]

http://faq.customtacticals.com/datasheets/52100.pdf

check the tempering graph.

anything under 400 F wont do anything.

note that its spot dependent for the area. a blade body at 180 F might be like 300 at the edge.

 

[teclis22]

i ddidnt understand though where you got the 900 F for infi.

http://www.uddeholm.de/german/files/downloads/VIKING-ENGLISH_990104.pdf

is -similar- to infi. note: not identical.

looking at the temper graph i would say anything over 300 f might be cutting it dangerously close.

 

[Grandsuave]

If one is going to do this much chopping, it is best to quench yourself with whiskey and beer for my INFI.

 

[Last Visible Canary]

i ddidnt understand though where you got the 900 F for infi.

http://www.uddeholm.de/german/files/downloads/VIKING-ENGLISH_990104.pdf

is -similar- to infi. note: not identical.

looking at the temper graph i would say anything over 300 f might be cutting it dangerously close.

the 900 is directly from Jerry Busse as quoted from the thread posted on the first page of this thread.

the steel posted and INFI aren't the same
INFI:---------------------------VIKING

C 0.5 -------------------------0.5
V 0.36 ------------------------0.5
Cr 8.25 -----------------------8.0
Co 0.95 -----------------------
Ni 0.74 ------------------------
Mo 1.3 ------------------------1.5
N 0.11 -------------------------

Mn-------x---------------------0.5
Silicon----x---------------------1.0


I need to find my machining book to find the chart describing the effects of individual elements to find the ones that increase red hardness, or look it up online. At the moment I don't have the time to do so, but needless to say the basic makeup of the two steels do not look similar enough to assume that their red hardness qualities would be the same. Certain elements can increase red hardness in metals that are designed to be used in die presses, where the metal constantly has friction heat applied to it in at 800 degree's or significantly higher. The thinner the edge of the die, the hotter it will tend to get while going through the stamp process. Individual microconstituents like .75% nitrogen and .75% nickel can make a big difference in the properties of the steel.

 

[tempey]

I've used mine as a fire poker, a rock chopper and a stake to keep beverages cold in the river.

Did the edge get damaged at all from chopping up rocks?

 

[Allcaps321]

I wouldn't worry about any steel being in the sun and the heat generated from chopping causing any problems. Metal is an excellent heat conductor and will dissipate the heat quickly enough to not be damaged.

 

[tomthebaker]

Pardon my academic terminology but your vocabulary is far too in dubious for my comprehension, so can you please endeavor to articulate this matter more distinctly.

 

[Revolverrodger]

It would be safer if you sent the knives to me, I live in Canada so we never see such high tempeatures !

 

[Mojo2010]

At Saudi desert where temp around low to middle 100 degree F (?), I probably concern about the scale/handle than the blade.

 

[Al-Sheikh]

Field experiment delivers stunning results :thumbup: Uploading pictures.

 

[Al-Sheikh]

Okay, so the idea is to heat up a dark coated INFI blade in direct sunlight and then chop and baton like a maniac. This is supposed to increase the blade temperature even further. Then we use a piece of paper as a reference medium: If the paper catches fire when the hot blade touches it, the blade temperature equals or is above 400F. Here we go:

Test arrangement:

Heat it up in sunlight:

Baton and chop with maximum speed and force:

Thrust blade though a piece of paper:

And my wife is also happy to have lots of kindling for her next smoke bath...

Do you want to believe???

 

[gkpfingsten]

I believe! Did you also make all of that kindling in one chop?

 

[Last Visible Canary]

did it actually set the paper on fire?

I'd honestly expect the initial batoning to reduce the temperature of the blade since the wood would not heat up as much in the direct sunlight. In order to start increasing the temp you'd first have to overcome the heat sink effect.

I am skeptical

 

[Al-Sheikh]

No fire spitting blade here

 

[Allcaps321]

If it was that hot how did you hold on to it bare handed?

 

[dingy]

does sunlight heat burns (ruins) the HT of a blade ? may be on Mars.

 

[Bigfattyt]

900F

I read so many remarks about belt sanding, that the blade "should not get warm to the touch". So I started treating my knives accordingly (put some distance between knife and camp fire, out of the sun on crazy hot days,...). But 900F literally means right into hell and back without problems. Very re-assuring :thumbup:

Part of the reason for that "don't let the blade get warm to the touch" is that when you are using a belt sander to on the blade, and you get the blade hot (especially by sharpening), you are generating all that heat at a very small contact point. The amount of heat you generate at the edge to transfer heat energy to the rest of the big hunk of steel to get it hot means you are getting a lot of heat energy passed through a small area. You can burn an edge up, and only have the rest of the blade get mildly warm. I have done this with 1/4 inch 5160 steel my self. Burned and blackened the tip, while the spine only got a bit warm to the touch. So easy does it with belt sharpening, especially the thinner the edge and closer to the tip you are!

5160 temper is affected at a much lower temp (in the 400 to 500 degree range), than INFI.

Your car's paint would bubble and smoke before Infi got hot enough to ruin the temper.

 

[Bigfattyt]

Serious question, can simple carbon steels like 1095 or 52100 get hot enough from use to harm the HT?

Satin blades get extremely hot when chopping and if you add the extra 150 or so degrees that sunlight adds to the temperature of a blade I sometimes get worried.

I believe SR 101 can be ruined of brought up over 350 degrees. While chopping on a sunny day for about 10 min my Rat Daddy LE got so hot I could barely touch the blade. I'm guessing around 180 degrees as any prolonged touch would have given me a burn.

Is it possible to ruin a simple carbon steel chopper just with sunlight and the friction produced from choppong?

Short answer would be no. Unless you mounted your KZII in a mechanical swinging arm of death machine, and set it loose on a forest of hardwood.

My answer is still no, even for simple carbon steels, without the mechanicalswingingarmofdeathmachine mentioned above.

Just think how hot a 350 degree cookie sheet is when you accidentally touch it while pulling cookies out of the oven. Instant painfull burn, with blisters. You would really notice if your full tang knife got that hot in your hand. Even with Res-c handles, I bet you will still notice!!!!