Remember when master knifemaker Bob Kramer came to the PopSci office just to slice our soda cans in half? Great fun! But how we wished we had had an ultra-slow-motion camera like the Phantom on hand that day.
We couldn't just let it go. So, armed with our own Kramer knife and our Phantom, we attempted to replicate the feat. It took a little practice, a lot of sharpening, and a pretty high knife-tip velocity, but here's the slow-mo video for your edification!
I recommend watching it full-screen.
And here -- just to refresh your memory -- is the master at work.
Undoubtedly a remarkable blade but this man is obviously not a metallurgist. Chromium cannot be used as an effective grain pinner, especially not at concentrations of 1.2 weight %. Grain pinning is usually achieved by microalloy additions of vanadium, titanium, or niobium. More likely, grain refinement was achieved by subsequent reaustenization during forging.
Also, since when is steel composed of molecules?! That statement made me shutter.
I'm also confused as to how this blade was made corrosion resistant. Normal stainless steels contain over 12 weight % Cr to create an effective chrome oxide layer that prevents corrosion. With 1 weight % C, the affinity to form Cr23C6 is going to be extremely high and vastly deplete the already low 1.2 weight % Cr that is freely available to form an oxide layer...
Regardless, it's an impressive blade; just the metallurgy is a little off.
I guess Joseph A. Bernstien is an intern?
Any idea what the videos never appear anywhere for me on these slow motion posts?
I can see all the other videos posted on this site except these. /moan i wanna see..
It's a flash player and not a Youtube video. Are you on an Apple product or something that doesn't support flash? May just need to go to Macro media and download Shockwave.
Thanks for trying man, i'll troubleshoot it from my home pc later today. Not on an apple hmm oddness.
Three bottles is nothing.
Check this guy's knives out:
Are you guys freaking DEAF!!!??? Why do you have the sound loud enough to rattle windows on these videos? My PC speaker volume is set to only 25% and starting one of these 2 videos wakes the dead!
The metallurgy is not off. He said grain size and the met stuff right. he was just trying to esplain in simple terms. The steel is low alloy high carbon steel high hardness. the grain boundary pinning is also right. Heavy deformation during fouding also contributes to the grain refinement.
Bottles and cans, just clap your hands!
Why does PopSci hate bottled water?
He hates these cans..... STAY AWAY FROM THE CANS!!!
@ spizarik; If you know that much, then you have to know that getting some rock-solid number to replace the inconsistent quantities in a given alloy is impossible. Stainless steel grades offer the example that it really is a general statement rather than any true rule or absolutely quantifiable content. The company that made the knife I carry in my pocket can't tell me what the actual carbon content of the blade is, because they cannot know for sure. If I make two stamping press dies side by side with the same basic material makeup of nickel, chromium, tin, vanadium, and carbon; and add equal amounts of carbon when I temper it in the same way for both-in the same kiln, I end up with two unique dies with truly different characteristics to try to make uniform parts with, and that I have to learn to work with over the life of the dies. Which continue to be altered divergently with each impact or heating until they are incompatible. This article is merely about a steel surface profile and it's tendencies versus a bottle of water. Kind of childish way to get the word out if you ask me. The old Ginsu demo of sawing on a hammerhead and then thin-slicing a tomato equaled more sales than this one will.
But...will it blend??