Full-sized specimens of oil well drill pipe are tested for resistance to stress failure and corrosion from brines in a machine developed by United States Steel Corp. National Tube Co., works at McKeesport, Pa. The six-ton unit tests sections of seamless pipe up to 8⅝-inches in diameter and from 24 to 120 inches long at rotational speeds up to 1000 revolutions per minute and at bending forces up to 1,200,-000 inch-pounds.
A 25-horsepower variable-speed motor drives the main spindle to which the sample to be tested is attached by a tool joint. The free end rotates in a roller bearing in the loading housing. Pivots connect this housing to a yoke that takes the pull of a spring that can exert a force of 10,000 pounds. The free end of the pipe is bent downward a measured amount, and as the pipe rotates the walls are alternately stretched and compressed....
