Weld Neck Flange 18 Inch Class 300 Posted on February 12, 2017July 1, 2017 Weld Neck Flange 18 Inch Class 300 Weld Neck Flange Class 300 Size NPS : 18″ Size DN : 450 mm. Weight : 145 kg. StudBolt Size : 1 1/4″ UNC Or (M33) x 195 Long No. of Bolts : 24 EA. Holes Diamater : 34.925 mm. [wpfilebase tag=file id=2180 /] ansi b16 5 ansi flange dimensions ansi flanges asme b16 5 Class 300 flange dimensions raised face flange Weld Neck Flange Weld Neck Flange Class 300