49 CFR § 179.100-10 - Postweld heat treatment.
(a) After welding is complete, steel tanks and all attachments welded thereto must be postweld heat treated as a unit in compliance with the requirements of AAR Specifications for Tank Cars, appendix W (IBR, see § 171.7 of this subchapter).
(b) For aluminum tanks, postweld heat treatment is prohibited.
(c) Tank and welded attachments, fabricated from ASTM A 240/A 240M (IBR, see § 171.7 of this subchapter), Type 304L or Type 316L materials do not require postweld heat treatment, but these materials do require a corrosion resistance test as specified in § 179.100-7(c)(2).
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