ASTM Class 300 Welding Neck Flanges

Nominal Pipe SizeOutside Diameter (O)Thickness (T)Raised Face Diameter (R)Length Thru Hub (Y)Point Of WeldHub Diameter (X)Bore (B)Approximate Weight (lbs)Bolt Circle (C)Number of HolesDiameter of Holes
1/2 3.75 0.56 1.38 2.06 0.84 1.50 0.62 2 2.63 4 0.63
3/4 4.63 0.63 1.69 2.25 1.05 1.88 0.82 3 3.25 4 0.75
1 4.88 0.69 2.00 2.44 1.32 2.13 1.05 4 3.50 4 0.75
1 1/4 5.25 0.75 2.50 2.56 1.66 2.50 1.38 5 3.88 4 0.75
1 1/2 6.13 0.81 2.88 2.69 1.90 2.75 1.61 7 4.50 4 0.88
2 6.50 0.88 3.63 2.75 2.38 3.31 2.07 9 5.00 8 0.75
2 1/2 7.50 1.00 4.13 3.00 2.88 3.94 2.47 12 5.88 8 0.88
3 8.25 1.13 5.00 3.13 3.50 4.63 3.07 15 6.63 8 0.88
3 1/2 9.00 1.19 5.50 3.19 4.00 5.25 3.55 18 7.25 8 0.88
4 10.00 1.25 6.19 3.38 4.50 5.75 4.03 25 7.88 8 0.88
5 11.00 1.38 7.31 3.88 5.56 7.00 5.05 32 9.25 8 0.88
6 12.50 1.44 7.31 3.88 6.63 8.13 6.07 42 10.63 12 0.88
8 15.00 1.63 10.63 4.38 8.63 10.25 7.98 67 13.00 12 1.00
10 17.50 1.88 12.75 4.63 10.75 12.63 10.02 91 15.25 16 1.13
12 20.50 2.00 15.00 5.13 12.75 14.75 12.00 140 17.75 16 1.25
14 23.00 2.13 16.25 5.63 14.00 16.75 13.25 180 20.25 20 1.25
16 25.50 2.25 18.50 5.75 16.00 19.00 15.25 250 22.50 20 1.38
18 28.00 2.38 21.00 6.25 18.00 21.00 17.25 320 24.75 24 1.38
20 30.50 2.50 23.00 6.38 20.00 23.13 19.25 400 27.00 24 1.38
22 33.00 2.63 25.25 6.50 22.00 25.25 21.25 465 29.25 24 1.63
24 36.00 2.75 27.25 6.63 24.00 27.63 23.25 580 32.00 24 1.63