no, nobody made gas pipe bikes in the '70s. It's incorrect to call straight-gauge tubing gas pipe.
Only the Japanese and Chinese made gas pipe bikes after WWII, and the Japanese only for a few years after WWII. . .
Some great and very lively frames were made from straight-gauge bicycle tubing. Including Raleigh Grand Prix (TI 20-30) and Super Course (Reynolds 531)
Gas pipe is Seam-Welded, fully-annealed low-carbon steel (0.15% C). It has a tensile strength of 50,000 psi (just above dead-soft) and the reason is so that gas pipe will always leak before it breaks.
Bicycle tubing was made by the companies that hot-pierced Seamless heat-treated aircraft structural tubing between the wars. By WWII, aluminum flanges had almost fully replaced steel tubing in aircraft structures. The people hot-piercing steel for seamless structural tubing had to find a new market and they began making bicycle specialty tubes (Reynolds, Columbus, Vitus, True Temper, TI, et.al.). The last great military aircraft using steel and plywood was the Mosquito, and it went 400 mph.
The seamless carbon steel tubes used in bikes is heat treated to 100,000 psi tenstile strength - twice the strength of gas pipe.
The TI 20-30 tubing that Raleigh made and used in their bottom-line frames is a C-Mn alloy steel.
The straight-gage seamless steel is still aircraft-grade structural tubing.
Higher-quality specialty bicycle tubes are butted, which means they're drawn to lighten them by reducing the center wall thickness while maintaining greater thickness at the ends for brazing/welding structural strength.
Reynolds 531 is a C-Mn alloy steel with a tensile strength of 125,000 psi.
Cr-Mo alloy steel has a tensile strength of 140,000 psi.
Microalloyed alloy steel (Reynolds 753) has a tensile-strength of 145,000 psi, and self-heat treats during cool-down from welding, to maintain that tensile strength in TiG-weld heat-affected zones.
Gas pipe (equivalent to boiler steel) was used for bikes before WWII. You can definitely argue that a c. 1900 Columbia is gas pipe, since Albert Pope's primary business was boilers.
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