ASME/ANSI B16.5 Class 600 WN

The Welding neck flanges is normally referred to as the high hub flange. It is designed to transfer stresses to the pipe, thereby reducing high stress concentrations at the base of the flange. The welding neck flange is the best designed butt-welded flange of those currently available because of its inherent structural value. It is expensive because of the design.

Nominal Pipe Size	Outside Diameter of Flange	Diameter of Raised Face	Thickness of Flanges Min.	Diameter of Hub	Hub Diameter Beginning of Chamfer	Length Through Hub	Bore	Diameter of Bolt Circle	Diameter of Bolt Holes	Number of Bolts	Approxi-mate Weight kgs
NPS	O	R	tf	X	A	Y	B	W	I	n
1/2	95	34.9	14.3	38	21.3	52	15.8	66.7	15.9	4	0.87
3/4	115	42.9	15.9	48	26.7	57	21.0	82.6	19.1	4	1.41
1	125	50.8	17.5	54	33.4	62	26.6	88.9	19.1	4	1.86
1 1/4	135	63.5	20.7	64	42.2	67	35.1	98.4	19.1	4	2.56
1 1/2	155	73.0	22.3	70	48.3	70	40.9	114.3	22.2	4	3.50
2	165	92.1	25.4	84	60.3	73	52.5	127.0	19.1	8	4.35
2 1/2	190	104.8	28.6	100	73.0	79	62.7	149.2	22.2	8	6.39
3	210	127.0	31.8	117	88.9	83	77.9	168.3	22.2	8	8.55
3 1/2	230	139.7	35.0	133	101.6	86	90.1	184.2	25.4	8	10.82
4	275	157.2	38.1	152	114.3	102	102.3	215.9	25.4	8	17.59
5	330	185.7	44.5	189	141.3	114	128.2	266.7	28.6	8	29.02
6	355	215.9	47.7	222	168.3	117	154.1	292.1	28.6	12	34.34
8	420	269.9	55.6	273	219.1	133	202.7	349.2	31.8	12	52.92
10	510	323.8	63.5	343	273.0	152	254.5	431.8	34.9	16	87.07
12	560	381.0	66.7	400	323.8	156	304.7	489.0	34.9	20	104.05
14	605	412.8	69.9	432	355.6	165	336.5	527.0	38.1	20	123.50
16	685	469.9	76.2	495	406.4	178	387.3	603.2	41.3	20	170.46
18	745	533.4	82.6	546	457.0	184	437.9	654.0	44.5	20	206.34
20	815	584.2	88.9	610	508.0	190	488.9	723.9	44.5	24	257.41
24	940	692.2	101.6	718	610.0	203	590.9	838.2	50.8	24	359.14