(a)(Reproduces 124.2.A.) Upon prolonged exposure to temperatures above 800 °F (427 °C), the carbide phase of plain carbon steel, plain nickel-alloy steel, carbon-manganese-alloy steel, manganese-vanadium-alloy steel, and carbon-silicon steel may convert to graphite.
(b)(Reproduces 124.2.B.) Upon prolonged exposure to temperatures above 875 °F (468 °C), the carbide phase of alloy steels, such as carbon-molybdenum, manganese-molybdenum-vanadium, manganese-chromium-vanadium, and chromium-vanadium, may convert to graphite.
(c)The design temperature of a piping system employing one or more of the materials listed in paragraphs (a) and (b) of this section must not exceed the lowest graphitization temperature specified for materials used. [CGFR 68-82, 33 FR 18843, Dec. 18, 1968, as amended by CGFR 69-127, 35 FR 9978, June 17, 1970; CGD 72-104R, 37 FR 14233, July 18, 1972; CGD 73-248, 39 FR 30839, Aug. 26, 1974; CGD 73-254, 40 FR 40165, Sept. 2, 1975; USCG-2003-16630, 73 FR 65183, Oct. 31, 2008; USCG-2020-0634, 89 FR 50153, June 12, 2024]