Section 154.630 - Cargo tank material(a) If a material of a cargo tank is not listed in §§ 154.610 , 154.615 or § 154.620 , the allowable stress of that material must be specially approved by the Commandant (CG-ENG).(b) For cargo tanks of aluminum alloys with welded connections, the minimum tensile strength ([SIGMA]B) for the calculations under § 154.440 , § 154.447 and § 154.450 must be the minimum tensile strength of the alloy in the annealed condition.(c) Increased yield strength and tensile strength of a material at low temperature for independent tanks type A, B, and C must be specially approved by the Commandant (CG-ENG).CGD 74-289, 44 FR 26009, May 3, 1979, as amended by CGD 82-063b, 48 FR 4782, Feb. 3, 1983