Long Weld Neck Flange

The Long Weld Neck Flange 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.

• Class 150 Long Weld Neck Flange
• Class 300 Long Weld Neck Flange
• Class 400 Long Weld Neck Flange
• Class 600 Long Weld Neck Flange
• Class 900 Long Weld Neck Flange
• Class 1500 Long Weld Neck Flange
• Class 2500 Long Weld Neck Flange

Long welding neck flange (integral flange), lwn flanges are similar to a standard Welding Neck flanges, but the “Neck” is considerably longer than other flanges. LWN flange is often used as a nozzle for a barrel or column. In addition, there are the type LWN Heavy Barrel (HB) and the Equal LWN Barrel (E); they have a different shape and a thicker “Wall”.
Acero has 3 warehouses in Wenzhou, Wuxi and Hebei. As one of the piping solution providers, Acero has been committed to providing one-stop solutions for projects in the fields of oil and gas, water, renewable energy and infrastructure. With years’ consistent dedication and innovation, our reliable, cost-effective and environment-friendly solutions have won clients’ wide recognition.

China long welding neck flange manufacturer Acero supplies long welding neck flange (integral flange), lwn flanges in alloy steel, Titanium, Stainless Steel etc.

Size
1/2″ – 56″ (DN15 to DN1,400)
Pressure
America Series:Class 150 ,Class 300, Class 600, Class 900A ,Class 1500,Class 2500.
Europe Series:PN2.5,PN6,PN10,PN16,PN25,PN40,PN63,PN100,PN160,PN250,PN320,PN400.
Flange Facing Types
America Series:Flat face(FF),Raised face(RF),Tongue(T),Groove(G),Female(F),Male(M),Ring type joints face(RJ/RTJ)
Europe Series:Type A(Flat Face),Type B(Raised Face),Type C(Tongue),Type D(Groove),Type E(Spigot),Type F(Recess),Type G(O-Ring Spigot),Type H(O-Ring Groove)
Material
Carbon steel: ASTM A105,ASTM A105N,GB 20,C22.8.
Alloy steel: ASTM/ASME A182 F1-F12-F11-F22- F5-F9- F91
Stainless steel: ASTM/ASME A182 F304-304L-304H-304LN-304N
ASTM/ASME A182 F316-316L-316H-316LN-316N-316Ti
ASTM/ASME A182 F321-321H, F347-347H
Low temperature steel: ASTM/ASME A350 LF2.
High performance steel: ASTM/ASME A694 F42 , F52, F56, F60, F65, F70
Standards
ASME ANSI B16.5,ASME ANSI B16.47.
API 605,API 6L.
MSS SP 44
CSA Z245.12
EN1092-1,EN1759-1.
DIN2565, DIN2566, DIN2567, DIN2568, DIN2569
BS1560,BS 4504,BS 10.
AFNOR NF E29-200-1
ISO7005-1
AS2129
JIS B2220
UNI 2276. UNI 2277.UNI 2278 .UNI 6089 .UNI 6090

Long Weld neck flange dimensions are covered in ASME B16.5 – which covers Pipe Flanges and Flanged Fittings for size NPS ½” to 24” for above NPS 26” to 60” it should be as per ASME B16.47.

During dimensional inspection of flange, you should check for

• Outer & Inner Diameter of body
• Bolt Circle & Bolt hole Diameter
• Thickness of weld end
• Length of the Hub
• Straightness and alignment of the bolt hole

Class 150 Long Weld Neck Flange Dimensions

Size in Inch	Size in mm	Outer Dia.	Flange Thick.	Hub OD	Weld Neck OD	RF Dia.	RF Height	PCD	Hub Length	No of Bolts	Bolt Size UNC	Machine Bolt Length	RF Stud Length	Hole Size	ISO Stud Size
		A	B	C	D	E	F	G	H
1/2	15	90	9.6	30	21.3	34.9	2	60.3	As Required	4	1/2	50	55	5/8	M14
3/4	20	100	11.2	38	26.7	42.9	2	69.9	As Required	4	1/2	50	65	5/8	M14
1	25	110	12.7	49	33.4	50.8	2	79.4	As Required	4	1/2	55	65	5/8	M14
1 1/4	32	115	14.3	59	42.2	63.5	2	88.9	As Required	4	1/2	55	70	5/8	M14
1 1/2	40	125	15.9	65	48.3	73	2	98.4	As Required	4	1/2	65	70	5/8	M14
2	50	150	17.5	78	60.3	92.1	2	120.7	As Required	4	5/8	70	85	3/4	M16
2 1/2	65	180	20.7	90	73	104.8	2	139.7	As Required	4	5/8	75	90	3/4	M16
3	80	190	22.3	108	88.9	127	2	152.4	As Required	4	5/8	75	90	3/4	M16
3 1/2	90	215	22.3	122	101.6	139.7	2	177.8	As Required	8	5/8	75	90	3/4	M16
4	100	230	22.3	135	114.3	157.2	2	190.5	As Required	8	5/8	75	90	3/4	M16
5	125	255	22.3	164	141.3	185.7	2	215.9	As Required	8	3/4	85	95	7/8	M20
6	150	280	23.9	192	168.3	215.9	2	241.3	As Required	8	3/4	85	100	7/8	M20
8	200	345	27	246	219.1	269.9	2	298.5	As Required	8	3/4	90	110	7/8	M20
10	250	405	28.6	305	273	323.8	2	362	As Required	12	7/8	100	115	1	M24
12	300	485	30.2	365	323.8	381	2	431.8	As Required	12	7/8	100	120	1	M24
14	350	535	33.4	400	355.6	412.8	2	476.3	As Required	12	1	115	135	1 1/8	M27
16	400	595	35	457	406.4	469.9	2	539.8	As Required	16	1	115	135	1 1/8	M27
18	450	635	38.1	505	457.2	533.4	2	577.9	As Required	16	1 1/8	125	145	1 1/4	M30
20	500	700	41.3	559	508	584.2	2	635	As Required	20	1 1/8	140	160	1 1/4	M30
24	600	815	46.1	663	610	692.2	2	749.3	As Required	20	1 1/4	150	170	1 3/8	M33

Class 300 Long Weld Neck Flange Dimensions

Size in Inch	Size in mm	Outer Dia.	Flange Thick.	Hub OD	Weld Neck OD	RF Dia.	RF Height	PCD	Hub Length	No of Bolts	Bolt Size UNC	Machine Bolt Length	RF Stud Length	Hole Size	ISO Stud Size
		A	B	C	D	E	F	G	H
1/2	15	95	12.7	38	21.3	34.9	2	66.7	As Required	4	1/2	55	65	5/8	M14
3/4	20	115	14.3	48	26.7	42.9	2	82.6	As Required	4	5/8	65	75	3/4	M16
1	25	125	15.9	54	33.4	50.8	2	88.9	As Required	4	5/8	65	75	3/4	M16
1 1/4	32	135	17.5	64	42.2	63.5	2	98.4	As Required	4	5/8	70	85	3/4	M16
1 1/2	40	155	19.1	70	48.3	73	2	114.3	As Required	4	3/4	75	90	7/8	M20
2	50	165	20.7	84	60.3	92.1	2	127	As Required	8	5/8	75	90	3/4	M16
2 1/2	65	190	23.9	100	73	104.8	2	149.2	As Required	8	3/4	85	100	7/8	M20
3	80	210	27	117	88.9	127	2	168.3	As Required	8	3/4	90	110	7/8	M20
3 1/2	90	230	28.6	133	101.6	139.7	2	184.2	As Required	8	3/4	95	110	7/8	M20
4	100	255	30.2	146	114.3	157.2	2	200	As Required	8	3/4	95	115	7/8	M20
5	125	280	33.4	178	141.3	185.7	2	235	As Required	8	3/4	110	120	7/8	M20
6	150	320	35	206	168.3	215.9	2	269.9	As Required	12	3/4	110	120	7/8	M20
8	200	380	39.7	260	219.1	269.9	2	330.2	As Required	12	7/8	120	140	1	M24
10	250	445	46.1	321	273	323.8	2	387.4	As Required	16	1	140	160	1 1/8	M27
12	300	520	49.3	375	323.8	381	2	450.8	As Required	16	1 1/8	145	170	1 1/4	M30
14	350	585	52.4	425	355.6	412.8	2	514.4	As Required	20	1 1/8	160	180	1 1/4	M30
16	400	650	55.6	483	406.4	469.9	2	571.5	As Required	20	1 1/4	165	190	1 3/8	M33
18	450	710	58.8	533	457	533.4	2	628.6	As Required	24	1 1/4	170	195	1 3/8	M33
20	500	775	62	587	508	584.2	2	685.8	As Required	24	1 1/4	185	205	1 3/8	M33
24	600	915	68.3	702	610	692.2	2	812.8	As Required	24	1 1/2	205	230	1 5/8	M39

	Class 400 Long Weld Neck Flange Dimensions 

Size in Inch	Size in mm	Outer Dia.	Flange Thick.	Hub OD	Weld Neck OD	RF Dia.	RF Height	PCD	Hub Length	No of Bolts	Bolt Size UNC	RF Stud Length	Hole Size	ISO Stud Size
		A	B	C	D	E	F	G	H
1/2	15	95	14.3	38	21.3	34.9	7	66.7	As Required	4	1/2	75	5/8	M14
3/4	20	115	15.9	48	26.7	42.9	7	82.6	As Required	4	5/8	90	3/4	M16
1	25	125	17.5	54	33.4	50.8	7	88.9	As Required	4	5/8	90	3/4	M16
1 1/4	32	135	20.7	64	42.2	63.5	7	98.4	As Required	4	5/8	95	3/4	M16
1 1/2	40	155	22.3	70	48.3	73	7	114.3	As Required	4	3/4	110	7/8	M20
2	50	165	25.4	84	60.3	92.1	7	127	As Required	8	5/8	110	3/4	M16
2 1/2	65	190	28.6	100	73	104.8	7	149.2	As Required	8	3/4	120	7/8	M20
3	80	210	31.8	117	88.9	127	7	168.3	As Required	8	3/4	125	7/8	M20
3 1/2	90	230	35	133	101.6	N/A	7	184.2	As Required	8	7/8	140	1	M24
4	100	255	35	146	114.3	157.2	7	200	As Required	8	7/8	140	1	M24
5	125	280	38.1	178	141.3	185.7	7	235	As Required	8	7/8	145	1	M24
6	150	320	41.3	206	168.3	215.9	7	269.9	As Required	12	7/8	150	1	M24
8	200	380	47.7	260	219.1	269.9	7	330	As Required	12	1	170	1 1/8	M27
10	250	445	54	321	273	323.8	7	387.4	As Required	16	1 1/8	190	1 1/4	M30
12	300	520	57.2	375	323.8	381	7	450.8	As Required	16	1 1/4	205	1 3/8	M33
14	350	585	60.4	425	355.6	412.8	7	514.4	As Required	20	1 1/4	210	1 3/8	M33
16	400	650	63.5	483	406.4	469.9	7	571.5	As Required	20	1 3/8	220	1 1/2	M36
18	450	710	66.7	533	457	533.4	7	628.6	As Required	24	1 3/8	230	1 1/2	M36
20	500	775	69.9	587	508	584.2	7	685.8	As Required	24	1 1/2	240	1 3/4	M39
24	600	915	76.2	702	610	692.2	7	812.8	As Required	24	1 3/4	265	1 7/8	M45

Class 600 Long Weld Neck Flange Dimensions

Size in Inch	Size in mm	Outer Dia.	Flange Thick.	Hub OD	Weld Neck OD	RF Dia.	RF Height	PCD	Hub Length	No of Bolts	Bolt Size UNC	RF Stud Length	Hole Size	ISO Stud Size
		A	B	C	D	E	F	G	H
1/2	15	95	14.3	38	21.3	34.9	7	66.7	As Required	4	1/2	75	5/8	M14
3/4	20	115	15.9	48	26.7	42.9	7	82.6	As Required	4	5/8	90	3/4	M16
1	25	125	17.5	54	33.4	50.8	7	88.9	As Required	4	5/8	90	3/4	M16
1 1/4	32	135	20.7	64	42.2	63.5	7	98.4	As Required	4	5/8	95	3/4	M16
1 1/2	40	155	22.3	70	48.3	73	7	114.3	As Required	4	3/4	110	7/8	M20
2	50	165	25.4	84	60.3	92.1	7	127	As Required	8	5/8	110	3/4	M16
2 1/2	65	190	28.6	100	73	104.8	7	149.2	As Required	8	3/4	120	7/8	M20
3	80	210	31.8	117	88.9	127	7	168.3	As Required	8	3/4	125	7/8	M20
3 1/2	90	230	35	133	101.6	N/A	7	184.2	As Required	8	7/8	140	1	M24
4	100	275	38.1	152	114.3	157.2	7	215.9	As Required	8	7/8	145	1	M24
5	125	330	44.5	189	141.3	185.7	7	266.7	As Required	8	1	165	1 1/8	M27
6	150	355	47.7	222	168.3	215.9	7	292.1	As Required	12	1	170	1 1/8	M27
8	200	420	55.6	273	219.1	269.9	7	349.2	As Required	12	1 1/8	190	1 1/4	M30
10	250	510	63.5	343	273	323.8	7	431.8	As Required	16	1 1/4	215	1 3/8	M33
12	300	560	66.7	400	323.8	381	7	489	As Required	20	1 1/4	220	1 3/8	M33
14	350	605	69.9	432	355.6	412.8	7	527	As Required	20	1 3/8	235	1 1/2	M36
16	400	685	76.2	495	406.4	469.9	7	603.2	As Required	20	1 1/2	255	1 5/8	M39
18	450	745	82.6	546	457	533.4	7	654	As Required	20	1 5/8	275	1 3/4	M42
20	500	815	88.9	610	508	584.2	7	723.9	As Required	24	1 5/8	285	1 3/4	M42

Class 900 Long Weld Neck Flange Dimensions

Size in Inch	Size in mm	Outer Dia.	Flange Thick.	Hub OD	Weld Neck OD	RF Dia.	RF Height	PCD	Hub Length	No of Bolts	Bolt Size UNC	RF Stud Length	Hole Size	ISO Stud Size
		A	B	C	D	E	F	G	H
1/2	15	120	22.3	38	21.3	34.9	7	82.6	As Required	4	3/4	110	7/8	M20
3/4	20	130	25.4	44	26.7	42.9	7	88.9	As Required	4	3/4	115	7/8	M20
1	25	150	28.6	52	33.4	50.8	7	101.6	As Required	4	7/8	125	1	M24
1 1/4	32	160	28.6	64	42.2	63.5	7	111.1	As Required	4	7/8	125	1	M24
1 1/2	40	180	31.8	70	48.3	73	7	123.8	As Required	4	1	140	1 1/8	M27
2	50	215	38.1	105	60.3	92.1	7	165.1	As Required	8	7/8	145	1	M24
2 1/2	65	245	41.3	124	73	104.8	7	190.5	As Required	8	1	160	1 1/8	M27
3	80	240	38.1	127	88.9	127	7	190.5	As Required	8	7/8	145	1	M24
4	100	290	44.5	159	114.3	157.2	7	235	As Required	8	1 1/8	170	1 1/4	M30
5	125	350	50.8	190	141.3	185.7	7	279.4	As Required	8	1 1/4	190	1 3/8	M33
6	150	380	55.6	235	168.3	215.9	7	317.5	As Required	12	1 1/8	190	1 1/4	M30
8	200	470	63.5	298	219.1	269.9	7	393.7	As Required	12	1 3/8	220	1 1/2	M36
10	250	545	69.9	368	273	323.8	7	469.9	As Required	16	1 3/8	235	1 1/2	M36
12	300	610	79.4	419	323.8	381	7	533.4	As Required	20	1 3/8	255	1 1/2	M36
14	350	640	85.8	451	355.6	412.8	7	558.8	As Required	20	1 1/2	275	1 5/8	M39
16	400	705	88.9	508	406.4	469.9	7	616	As Required	20	1 5/8	285	1 3/4	M42
18	450	785	101.6	565	457	533.4	7	685.8	As Required	20	1 7/8	325	2	M48
20	500	855	108	622	508	584.2	7	749.3	As Required	20	2	350	2 1/8	M52
24	600	1040	139.7	749	610	692.2	7	901.7	As Required	20	2 1/2	440	2 5/8	M64

Class 1500 Long Weld Neck Flange Dimensions

Size in Inch	Size in mm	Outer Dia.	Flange Thick.	Hub OD	Weld Neck OD	RF Dia.	RF Height	PCD	Hub Length	No of Bolts	Bolt Size UNC	RF Stud Length	Hole Size	ISO Stud Size
		A	B	C	D	E	F	G	H
1/2	15	120	22.3	38	21.3	34.9	7	82.6	As Required	4	3/4	110	7/8	M20
3/4	20	130	25.4	44	26.7	42.9	7	88.9	As Required	4	3/4	115	7/8	M20
1	25	150	28.6	52	33.4	50.8	7	101.6	As Required	4	7/8	125	1	M24
1 1/4	32	160	28.6	64	42.2	63.5	7	111.1	As Required	4	7/8	125	1	M24
1 1/2	40	180	31.8	70	48.3	73	7	123.8	As Required	4	1	140	1 1/8	M27
2	50	215	38.1	105	60.3	92.1	7	165.1	As Required	8	7/8	145	1	M24
2 1/2	65	245	41.3	124	73	104.8	7	190.5	As Required	8	1	160	1 1/8	M27
3	80	265	47.7	133	88.9	127	7	203.2	As Required	8	1 1/8	180	1 1/4	M30
4	100	310	54	162	114.3	157.2	7	241.3	As Required	8	1 1/4	195	1 3/8	M33
5	125	375	73.1	197	141.3	185.7	7	292.1	As Required	8	1 1/2	250	1 5/8	M39
6	150	395	82.6	229	168.3	215.9	7	317.5	As Required	12	1 3/8	260	1 1/2	M36
8	200	485	92.1	292	219.1	269.9	7	393.7	As Required	12	1 5/8	290	1 3/4	M42
10	250	585	108	368	273	323.8	7	482.6	As Required	12	1 7/8	335	2	M48
12	300	675	123.9	451	323.8	381	7	571.5	As Required	16	2	375	2 1/8	M52
14	350	750	133.4	495	355.6	412.8	7	635	As Required	16	2 1/4	405	2 3/8	M56
16	400	825	146.1	552	406.4	469.9	7	704.8	As Required	16	2 1/2	445	2 5/8	M64
18	450	915	162	597	457	533.4	7	774.7	As Required	16	2 3/4	495	2 7/8	M72
20	500	985	177.8	641	508	584.2	7	831.8	As Required	16	3	540	3 1/8	M76
24	600	1170	203.2	762	610	692.2	7	990.6	As Required	16	3 1/2	615	3 5/8	M90

Class 2500 Long Weld Neck Flange Dimensions

Size in Inch	Size in mm	Outer Dia.	Flange Thick.	Hub OD	Weld Neck OD	RF Dia.	RF Height	PCD	Hub Length	No of Bolts	Bolt Size UNC	RF Stud Length	Hole Size	ISO Stud Size
		A	B	C	D	E	F	G	H
1/2	15	135	30.2	43	21.3	34.9	7	88.9	As Required	4	3/4	120	7/8	M20
3/4	20	140	31.8	51	26.7	42.9	7	95.2	As Required	4	3/4	125	7/8	M20
1	25	160	35	57	33.4	50.8	7	108	As Required	4	7/8	140	1	M24
1 1/4	32	185	38.1	73	42.2	63.5	7	130.2	As Required	4	1	150	1 1/8	M27
1 1/2	40	205	44.5	79	48.3	73	7	146	As Required	4	1 1/8	170	1 1/4	M30
2	50	235	50.9	95	60.3	92.1	7	171.4	As Required	8	1	180	1 1/8	M27
2 1/2	65	265	57.2	114	73	104.8	7	196.8	As Required	8	1 1/8	195	1 1/4	M30
3	80	305	66.7	133	88.9	127	7	228.6	As Required	8	1 1/4	220	1 3/8	M33
4	100	355	76.2	165	114.3	157.2	7	273	As Required	8	1 1/2	255	1 5/8	M39
5	125	420	92.1	203	141.3	185.7	7	323.8	As Required	8	1 3/4	300	1 7/8	M45
6	150	485	108	235	168.3	215.9	7	368.3	As Required	8	2	345	2 1/8	M52
8	200	550	127	305	219.1	269.9	7	438.2	As Required	12	2	380	2 1/8	M52
10	250	675	165.1	375	273	323.8	7	539.8	As Required	12	2 1/2	490	2 5/8	M64
12	300	760	184.2	441	323.8	381	7	619.1	As Required	12	2 3/4	540	2 7/8	M72

Disclaimer –  Please check with ASME B16.5 Before using.