Ed Huntress wrote:
On Wed, 16 May 2012 14:38:29 -0700, David Harmon
wrote:

On Wed, 16 May 2012 08:54:55 -0700 in rec.crafts.metalworking, Carla
Fong wrote,
In case you ever wondered why your drill won't go through that angle
iron you salvaged from an old bed frame or street sign:
Once I tried to cut some bed frame with a reciprocating (Sawzall-type)
saw with a "metal cutting" blade. Fortunately, it was my friend's saw.

If you get a look at the alloy makeup for train rails, you'll see why
that is. It's potentially quite hard -- carbon runs up to 0.80% by the
ASTM standard, and it contains manganese (1%), which augments the
hardening effect of the carbon. As-rolled, it comes in around 400 Bhn
(Rc 43). It may actually be harder when re-rolled, because the thinner
sections generally cause more work-hardening.

On top of that, older-spec rails can contain relatively high levels of
sulfur, phosphorus, and silicon. You get some weird microstructures
when you heat that and re-roll it.

Rolled as rails, the steel is intended to have a totally pearlitic
structure. It's hard and strong but other properties, such as
elongation, can be lousy. So it's likely to be nasty to cut, a bugger
to weld, very hard but with very little ductility.

'Great for a railroad. Not bad for a bedframe. Otherwise, IMO, it's
junk.


Works pretty good for small anvils. I use it for knife making anvils and
small parts.

--
Steve W.