[TheForge] What kind of steel is this

[H and P Foster]

A few months ago I was at a scrap yard and found and bought about 80 feet of
1/4" round stock.  One of the first things I did with it was for a project
that required forging and drilling of a hole.  No way could I drill the
hole.  I carried on with some other stock for that project and forgot about
that material until today.

What I was doing today did not require any drilling, only fitting to shape
and some brazing. The material took the brazing ok, but when it cooled down
and I was making small adjustments to the shape, it promptly broke cleanly
in half.  This happened twice. What kind of material would do that?

thanks for any help.

Harry Foster
Rusty Dog Forge