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Roy J
 
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Default Old Steel - New Steel

When you buy 10,000 pound rolls of cold rolled steel for
automobile fenders, the quality control is supurb, much better
than it ever was in the old days. If you buy merchant grade flat,
angle, and rebar from an electric furnace scrap melter, the
carbon and alloy content can vary wildly. Older bar came directly
from the steel mill, much more uniform.

We wiped out 3 blades on a horizontal bandsaw in an hour one day
on a process that we had done for several years. Problem was
traced down to ONE bar of 1/4"x2" flat stock that had a huge
carbon content, the HAZ was hard as a file.

Jim Stewart wrote:

A couple of weeks ago at the recycling center, a
welder was unloading some 1/2" square steel bar.
I asked him if it was mild steel and he replied
"yes, old mild steel, the best" I've heard
references to "old steel" being better than "new
steel" and I've never understood what the difference
is.