Will someone explain this term?

[cutacroshorty]

What is Cryogenic? I hear this term occasionally about freezing the metal in knife blades but, is this really a bunch of hype?

[calico jack]

This is a real process in which the steel is cooled by freezing below 0-degrees to lock in more carbon. When water or gas cooled, steel loses more carbon due to the longer cooling time. I have a couple of cryo-edged blades that seem to hold an edge longer, but sometimes are a little tough to sharpen. Cold Steel makes some of the best I've found. Theirs are 420HC J2 tool steel, cryo'd at 120 degrees below.

[redshanks]

It's my understanding that Cryogenic freezing as it pertains to metallurgy, involves the deep freezing of various metals in liquid nitrogen, down to minus 300-320 degrees Fahrenheit, in order to make it stronger or to maintain sharp edges longer. The process changes the molecular structure of the steel, not by "locking in more carbon," but rather by changing any Austenite content (larger grained carbon) remaining after the heat treat, into Martensite (smaller grained, more wear resistant carbon).

[calico jack]

I stand corrected. I mis-spoke, but in my own defense, I was between my 23rd and 24th consecutive 12-hour work day. Someone remind me to sleep before I open my mouth again.

[sunburst]

Hey Calico,

What in the heck is so important that you are working that many 12 hour days consecutavely???


Sunburst

[calico jack]

I work for a major automotive parts supplier, and our customers are very demanding(BMW). We're short on people, so we just suck it up and work. Besides, if the company is crazy enough to pay me, I'm just stubborn enough to show up and take their money.

[redshanks]

No problem Jack, you had the right idea. The minutiae is not worth dwelling on.