Weld Neck Flange 12 Inch Class 300 Posted on February 12, 2017July 1, 2017 Weld Neck Flange 12 Inch Class 300 Weld Neck Flange Class 300 Size NPS : 12″ Size DN : 300 mm. Weight : 64 kg. StudBolt Size : 1 1/8″ UNC Or (M30) x 170 Long No. of Bolts : 16 EA. Holes Diamater : 31.75 mm. [wpfilebase tag=file id=2177 /] 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