49 C.F.R. § 179.201-5 Postweld heat treatment and corrosion resistance.
Title 49 - Transportation
(a) Tanks and attachments welded directly thereto must be postweld heat treated as a unit at the proper temperature except as indicated below. Tanks and attachments welded directly thereto fabricated from ASTM A 240/A 240M (IBR, see §171.7 of this subchapter) Type 430A, Type 304 and Type 316 materials must be postweld heat treated as a unit and must be tested to demonstrate that they possess the corrosion resistance specified in §179.200–7(d), Footnote 2. Tanks and attachments welded directly thereto, fabricated from ASTM A 240/A 240M Type 304L or Type 316L materials are not required to be postweld heat treated. (b) Tanks and attachments welded directly thereto, fabricated from ASTM A 240/A 240M Type 304L and Type 316 materials must be tested to demonstrate that they possess the corrosion resistance specified in §179.200–7(d), Footnote 2. [68 FR 75762, Dec. 31, 2003]
Title 49: Transportation
PART 179—SPECIFICATIONS FOR TANK CARS
Subpart D—Specifications for Non-Pressure Tank Car Tanks (Classes DOT-111AW and 115AW)
§ 179.201-5 Postweld heat treatment and corrosion resistance.