Section 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.Amdt. 179-9, 36 FR 21341, Nov. 6, 1971, as amended at 68 FR 75762 , Dec. 31, 2003