Paul,
This link gives specs for one brand of sucker rod. In the picture shown you are looking at the male end of the rod. This link was shared by IFI member Irnsrgn, one night in the chat room, that I bookmarked. So Thanks Irnsrgn.
To answer your question, It is used link the above ground mechanical pump rig to the underground pump unit. This pumps are used to pump oil and etc. from bottom of a well.
Nos, Look on the flats of the square part of the ends, to see what kind of steel your rod is.
Let your imagination be your guide as to what make with your material.
Larry