I don't know their proper name, but the pictures look very much like the plugs my father in law carried with him when he worked as a pumper for wells in the Oklahoma oil field. They were use to patch holes in oil storage tanks, sometimes a rusted out hole, sometimes a bullet hole. He would just screw them in until they stopped the leak. As far as I can remember, that was considered a "permanent" repair.
Hope this helps!
Bill D.
