49 CFR 179.220-10 - Welding.
(a) All joints must be fusion welded in compliance with AAR Specifications for Tank Cars, appendix W (IBR, see § 171.7 of this subchapter). Welding procedures, welders, and fabricators shall be approved.
(b) Radioscopy of the outer shell is not a specification requirement.
(c) Welding is not permitted on or to ductile iron or malleable iron fittings.