NR196701 Survey of High-Strength Structural Steels for Pipeline Applications

Over the years, there has been a continuing trend toward the use of higher strength steels in the manufacture of gas-transmission line pipe. In looking for ways to obtain higher strength pipe, there are, in general, two approaches that can be considered. One involves the continued use of pre-strengthened steel plate that is formed in to a tube and welded, while the other involves forming the pipe from a suitable steel in the as-rolled or softened condition, welding, and then heat treating the final product to obtain the desired strength. Both methods offer certain advantages, but neither offers a completely satisfactory solution to the problem without further development work in one or more critical areas. A survey of the properties of 82 commercially available structural steels with yield strengths in the range of 70 to 175 ksi was conducted. Of the steels surveyed, 11 attain yield strengths in the range of 70 to 90 ksi in the as-rolled condition, and 2 attain yield strengths of 97 ksi by precipitation hardening; the remainder developed their properties by quenching and tempering.