"Fdmorrison" wrote in message
...

I won't try to elaborate on this here because it's worth
a chapter or two of a book. You can find a better explanation in any
introductory metallurgy book, even the non-mathematical, practical ones
that
are used for teaching it as technology, rather than as science.

I wish those texts didn't make a distinction between technology and
science.
So much for books.

Well, for textbook purposes, the books written for "technology" programs are
either qualitative, in which case they don't use math at all; or they're
quantitive, but without the use of calculus or other math that most people
don't learn in high school.

I prefer the books written for technology programs, rather than the
engineering-program versions, in many cases. Anything I'm interested in
usually is well covered that way. For example, the courses I had in statics
and mechanics were non-calculus courses (I took them years after college),
and I got everything I wanted out of them. It was just to satisfy my hobby
interest. I wasn't looking for a brain workout with abstraction and rigor.


When I learned basic blacksmithing, I was taught that once you changed the
iron's(steel's) shape the grain (molecular) structure got stressed, so to
relieve this the iron is heated and allowed to cool (aneal), even for mild
steel.
So in the changing of shape in drawing, there's a similar stress
(hardening)
added to the steel?

Yes, drawing is just one way of work-hardening. It's usually the best way to
gain the greatest unidirectional tensile strength in a material. It also
gives you the best combination of toughness and hardness in many cases.

Keep in mind that the strength and hardness of most metals are directly
related. In the case of steel, they actually publish tables that relate
Brinell hardness to tensile strength.

They assume that the steel is hardened as well as it can be for those
tables. In other words, they assume that you haven't overheated the metal
and caused a lot of grain growth. If the metal has been cold-worked with a
hammer or a press, they assume that you didn't exceed the ultimate
compression strength in the process of hammering, which will cause cracks
and other faults. If you either heat-treat or work-harden badly, you'll have
the local hardness, but not the strength in the whole mass that you should
have.

--
Ed Huntress
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