--- In STMFC@..., Anthony Thompson <thompson@s...> wrote:

A.T. Kott wrote:

Tony - The "iron" wheels were really chilled iron wheels -

actually a

composite of two different forms of cast iron in a single casting.

Yes. I'm a metallurgist and understand the product....

Tony - I did not know you are a metallurgist!! I have a couple of
questions for you regarding "wrought steel wheels" - how the heck did
they make them? Were they forged hot between dies? Is that what the
term "wrought" means?

In one of my previous rambling posts, I discussed casting of trailing
truck sideframes and cracking. It was my understanding from
somewhere that "cast steel wheels" suffered from the same cracking
problems until just prior to WWII. At that time, foundries figured
out how to design and cool them properly so that they were not prone
to cracks.

Also, someone mentioned that 1" wear was a lot on a freight car
wheel. About 20 years ago, when a group of us were discussing
potential wheel standards for PROTO48 (a type of "O" scale fine
scale), the question of flange depth arose. From a MODEL engineering
standpoint, it is desirable to have the deepest flange possible. The
flange depth on a new prototype wheel was 1" high, as I recall. The
flange depth on a wheel at the condemning limit was 1-1/2". This
corresponds to 0.021" and 0.031" respectively in 1/48 scale. As I
recall, the flange depth of 0.026" was chosen for the standard, since
it represented a wheel halfway to the wear limit on the prototype.
("O" scale finescale, by comparison, has a 0.021" flange depth -
representing a new wheel).

So, I guess that 1/2" of tread wear into the chilled iron wheel
perimeter would be the maximum allowable wear.

A.T. Kott