Guys, I picked up a rusty piece of steel and needing to turn it down I tried
cutting it in my band saw. Lo and behold, it would only cut about 3/16"
deep. I tried to cut a section off with my acetylene torch and it wouldn't
even get red!!!! Finally had to grind it in two. It looks like a 1 5/8"
diameter rod with a half inch hole down the center. Further examination
reveals that it is a piece of soft steel (1018?) surrounding a harder
(obviously) tube. Specs follow:
OD 1.630. Diameter of core piece 1.245. Diameter of hole is .535. The
core is packed with with what looks like rusty swarf, or chips. But they
are only mildly attracted to a magnet. The hard core piece machines nicely
with carbide, and the chips are magnetic. The outer tube appears to be mild
steel. On a polished end, there is apparently a very thin layer of copper
or brass between the outer and inner pieces. But the most remarkable thing
is that I held the flame of the cutting torch on the core piece for at least
5 minutes without it getting hot enough to cut. Oh, color of the grinding
sparks is almost the same as the sparks from the outer tube, IOW low carbon
steel sparks.

For the life of me, I cannot figure out what the material is, what it is
used for, or how it was made. Anyone have any ideas?

Thanks, James Johnson
Bewildered in Texas