1. Introduction: ANSI B16.5 Class 150 Weld Neck Flange consists of a circular fitting with a protruding rim around the circumference. Generally machined from a forging, these Flanges are typically butt Welded to a pipe.
2. Description: Weld neck flanges are visually different from other flange types by their long tapered hub and smooth transition of thickness up to where the butt weld joins to a pipe or a fitting. The tapered hub provides reinforcement, and the added length helps for resistance to dishing during the welding process. Weld neck flanges are typically used in severe service conditions, whether loading conditions are substantially constant or fluctuate between wide limits.
3. Specification:
Nominal Pipe Size
|
Outside Diameter (O)
|
Thickness (T)
|
Raised Face Diameter (R)
|
Length Thru Hub (Y)
|
Point of Weld (A)
|
Hub Diameter (X)
|
Bore (B)
|
Approximate Weight (lbs)
|
Bolt Circle (C)
|
Number of Holes
|
Diameter of Holes
|
1/2
|
3.5
|
0.44
|
1.38
|
1.88
|
0.84
|
1.19
|
0.62
|
2
|
2.38
|
4
|
0.63
|
3/4
|
3.88
|
0.5
|
1.69
|
2.06
|
1.05
|
1.5
|
0.82
|
2
|
2.75
|
4
|
0.63
|
1
|
4.25
|
0.56
|
2
|
2.19
|
1.32
|
1.94
|
1.05
|
3
|
3.13
|
4
|
0.63
|
1 1/4
|
4.63
|
0.63
|
2.5
|
2.25
|
1.66
|
2.31
|
1.38
|
3
|
3.5
|
4
|
0.63
|
1 1/2
|
5
|
0.69
|
2.88
|
2.44
|
1.9
|
2.56
|
1.61
|
4
|
3.88
|
4
|
0.63
|
2
|
6
|
0.75
|
3.63
|
2.5
|
2.38
|
3.06
|
2.07
|
6
|
4.75
|
4
|
0.75
|
2 1/2
|
7
|
0.88
|
4.13
|
2.75
|
2.88
|
3.56
|
2.47
|
8
|
5.5
|
4
|
0.75
|
3
|
7.5
|
0.94
|
5
|
2.75
|
3.5
|
4.25
|
3.07
|
10
|
6
|
4
|
0.75
|
3 1/2
|
8.5
|
0.94
|
5.5
|
2.81
|
4
|
4.81
|
3.55
|
12
|
7
|
8
|
0.75
|
4
|
9
|
0.94
|
6.19
|
3
|
4.5
|
5.31
|
4.03
|
15
|
7.5
|
8
|
0.75
|
5
|
10
|
0.94
|
7.31
|
3.5
|
5.56
|
6.44
|
5.05
|
19
|
8.5
|
8
|
0.88
|
6
|
11
|
1
|
8.5
|
3.5
|
6.63
|
7.56
|
6.07
|
24
|
9.5
|
8
|
0.88
|
8
|
13.5
|
1.13
|
10.63
|
4
|
8.63
|
9.69
|
7.98
|
39
|
11.75
|
8
|
0.88
|
10
|
16
|
1.19
|
12.75
|
4
|
10.75
|
12
|
10.02
|
52
|
14.25
|
12
|
1
|
12
|
19
|
1.25
|
15
|
4.5
|
12.75
|
14.38
|
12
|
80
|
17
|
12
|
1
|
14
|
21
|
1.38
|
16.25
|
5
|
14
|
15.75
|
13.25
|
110
|
18.75
|
12
|
1.13
|
16
|
23.5
|
1.44
|
18.5
|
5
|
16
|
18
|
15.25
|
140
|
21.25
|
16
|
1.13
|
18
|
25
|
1.56
|
21
|
5.5
|
18
|
19.88
|
17.25
|
150
|
22.75
|
16
|
1.25
|
20
|
27.5
|
1.69
|
23
|
5.69
|
20
|
22
|
19.25
|
180
|
25
|
20
|
1.25
|
22
|
29.5
|
1.81
|
25.25
|
5.88
|
22
|
24.25
|
21.25
|
225
|
27.25
|
20
|
1.38
|
24
|
32
|
1.88
|
27.25
|
6
|
24
|
26.13
|
23.25
|
260
|
29.5
|
20
|
1.38
|
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