Materials.

(a) Steel plate material used to fabricate tanks must conform with the following specifications with the indicated minimum tensile strength and elongation in the welded condition. However, the maximum allowable carbon content for carbon steel must not exceed 0.31 percent, although the individual ASTM specification may allow for a greater amount of carbon. The plates may be clad with other approved materials:

Specifications Tensile strength (psi) welded condition 1 (minimum) Elongation in 2 inches (percent) welded condition 1 (longitudinal) (minimum) ASTM A 240 type 304 75,000 25 ASTM A 240 type 304L 70,000 25 ASTM A 240 type 316 75,000 25 ASTM A 240 type 316L 70,000 25 ASTM A 240 type 321 75,000 25 ASTM A285 Gr. A 45,000 29 ASTM A285 Gr. B 50,000 20 ASTM A285 Gr. C 55,000 20 ASTM A515 Gr. 65 65,000 20 ASTM A515 Gr. 70 70,000 20 ASTM A516 Gr. 70 70,000 20 1 Maximum stresses to be used in calculations.

(b) [Reserved]

(c) All plates must have their heat number and the name or brand of the manufacturer legibly stamped on them at the rolling mill.

[Amdt. 179-10, 36 FR 21355, Nov. 6, 1971, as amended by Amdt. 179-42, 54 FR 38798, Sept. 20, 1989; Amdt. 179-43, 55 FR 27642, July 5, 1990; Amdt. 179-52, 61 FR 28682, June 5, 1996; Amdt. 179-52, 61 FR 50255, Sept. 25, 1996; Amdt. 179-53, 61 FR 51342, Oct. 1, 1996]