[TheForge] Burning Metal

[Demon Buddha]

On Sun, 2 Nov 2003 13:44:52 -0500, DillonCo <dillonco@comcast.net> wrote:

> I heard that one can burn metal, but I couldn't find much information on 
> it
> so I have a few questions:
> What happens (molecularly) when metal is burned?

	Burning metal usually refers to iron and its alloys.  It is the process
	of oxidizing the iron at a high rate.  That is how an oxy-acetylene
	torch operates.  Bring the metal up to MP and then inject a jet of pure
	oxygen.  The jet serves to oxidize the molten iron/steel and to blow the
	molten oxides away from the immediate area of the flame.

> What metals can this happen to?

	Iron is the only one I know of.  I'm not an expert in this.
	I know you cannot burn copper with an O-A torch, which is why
	copper alloys such as Be-Cu are used as components in safe
	construction.  Clad a safe in 4" of Be-Cu and thieve cannot
	silently cut through.  Inside the copper you have high strength
	steel alloys as well as other elements to defeat drilling.

	I worked for a guy in 1982 who at one time was a designer of
	safes.  He told me he's used all manner of tricky stuff.
	On one safe there was a two inch inner layer of pure niobium.
	If you've ever worked this material, which I have, you will know
	that annealed Nb is virtually impossible to machine.  Try putting
	a drill through that depth of Nb.  You will eventually succeed
	(probably, anyhow) but it will take you a LONG time, and that is
	the point.  Not to make it impossible to get in but to make it
	such a godawful pain in the ass that thieves either give up in
	frustration (time is their enemy), or never bother in the first
	place.

	Oh, in case you are wondering: Nb is SO soft and gummy that even the
	sharpest cutting tool cannot cut it. The best that happens is a ridge
	of metal builds up at the cutting edge and moves like a wave of metal
	along the edge.  It generates a fair amount of heat, too.  Trying to
	drill a 1" hole through a 2" thick Nb plate would be painful.
>