Weld Neck Flange

A Weld neck flange is a type of flange designed to be welded onto the end of a pipe. It’s distinguished by its long neck, which is beveled to match the bevel on the pipe. The purpose of the neck is to transfer stress from the flange to the pipe, reducing the concentration of stress at the base of the flange. This design helps to prevent cracking and leaking, making weld neck flanges particularly suitable for high-pressure and high-temperature applications.

Weld neck flanges typically have a raised face, which provides a sealing surface when bolted to a mating flange or fitting. They are commonly used in industries such as oil and gas, petrochemical, power generation, and process piping systems where reliable sealing under extreme conditions is essential.

Long Weld Neck Flange (LWN Flange)

A Long Weld Neck Flange (LWN Flange) is a specialized type of flange commonly used in high-pressure and high-temperature piping systems. It is characterized by its long, tapered neck that seamlessly connects to a pipe, providing enhanced structural integrity and reducing stress concentrations in critical applications.

Types of Long Weld Neck Flanges:

Standard Long Weld Neck: Regular design for general-purpose use.
Heavy Wall Long Weld Neck: Extra thickness for added strength in heavy-duty applications.
Custom Designs: Tailored to meet specific project requirements.

Benefits:

Reduces the risk of leakage due to its strong weld connection.
Minimizes stress at the junction of the flange and pipe.
Provides a seamless connection for critical applications.

Material

Carbon Steel
1. ASTM A105, ASTM A350 LF2, ASTM A694
2. Cost-effective and widely used for general-purpose applications.
Stainless Steel
1. Grades: 304/304L, 316/316L, 904L, Duplex (2205), Super Duplex (2507)
2. Offers excellent corrosion resistance and durability.
Alloy Steel
1. Grades: ASTM A182 F5, F9, F11, F22, F91
2. Designed for high-temperature and high-pressure environments.

Class 150 Weld Neck Flange Dimensions

Size in Inch	Size in mm	Outer Diameter	Flange Thickness	Hub OD	Weld Neck OD	Welding Neck Length	Bore	RF Diameter	RF Height	PCD	Weld Face
		A	B	C	D	E	F	G	H	I	J
1/2	15	90	9.6	30	21.3	46		34.9	2	60.3	1.6
3/4	20	100	11.2	38	26.7	51		42.9	2	69.9	1.6
1	25	110	12.7	49	33.4	54		50.8	2	79.4	1.6
1 1/4	32	115	14.3	59	42.2	56		63.5	2	88.9	1.6
1 1/2	40	125	15.9	65	48.3	60		73	2	98.4	1.6
2	50	150	17.5	78	60.3	62		92.1	2	120.7	1.6
2 1/2	65	180	20.7	90	73	68		104.8	2	139.7	1.6
3	80	190	22.3	108	88.9	68		127	2	152.4	1.6
3 1/2	90	215	22.3	122	101.6	70	Welding Neck bore is derived from the pipe schedule	139.7	2	177.8	1.6
4	100	230	22.3	135	114.3	75		157.2	2	190.5	1.6
5	125	255	22.3	164	141.3	87		185.7	2	215.9	1.6
6	150	280	23.9	192	168.3	87		215.9	2	241.3	1.6
8	200	345	27	246	219.1	100		269.9	2	298.5	1.6
10	250	405	28.6	305	273	100		323.8	2	362	1.6
12	300	485	30.2	365	323.8	113		381	2	431.8	1.6
14	350	535	33.4	400	355.6	125		412.8	2	476.3	1.6
16	400	595	35	457	406.4	125		469.9	2	539.8	1.6
18	450	635	38.1	505	457.2	138		533.4	2	577.9	1.6
20	500	700	41.3	559	508	143		584.2	2	635	1.6
24	600	815	46.1	663	610	151		692.2	2	749.3	1.6

Class 150 Weld Neck Flange Stud & Bolt Dimensions

Size in Inch	Size in mm	No of Bolts	Bolt Size UNC	Machine Bolt Length	RF Stud Length	Hole Size	ISO Stud Size	Weight in kg
1/2	15	4	1/2	50	55	5/8	M14	0.6
3/4	20	4	1/2	50	65	5/8	M14	0.9
1	25	4	1/2	55	65	5/8	M14	1.4
1 1/4	32	4	1/2	55	70	5/8	M14	1.4
1 1/2	40	4	1/2	65	70	5/8	M14	1.8
2	50	4	5/8	70	85	3/4	M16	2.7
2 1/2	65	4	5/8	75	90	3/4	M16	3.7
3	80	4	5/8	75	90	3/4	M16	4.6
3 1/2	90	8	5/8	75	90	3/4	M16	5.5
4	100	8	5/8	75	90	3/4	M16	6.8
5	125	8	3/4	85	95	7/8	M20	8.7
6	150	8	3/4	85	100	7/8	M20	10.9
8	200	8	3/4	90	110	7/8	M20	17.7
10	250	12	7/8	100	115	1	M24	24
12	300	12	7/8	100	120	1	M24	37
14	350	12	1	115	135	1 1/8	M27	50
16	400	16	1	115	135	1 1/8	M27	64
18	450	16	1 1/8	125	145	1 1/4	M30	68
20	500	20	1 1/8	140	160	1 1/4	M30	82
24	600	20	1 1/4	150	170	1 3/8	M33	118

Class 300 Weld Neck Flange Dimensions

Size in Inch	Size in mm	Outer Diameter	Flange Thickness	Hub OD	Weld Neck OD	Welding Neck Length	Bore	RF Diameter	RF Height	PCD	Weld Face
		A	B	C	D	E	F	G	H	I	J
1/2	15	95	12.7	38	21.3	51		34.9	2	66.7	1.6
3/4	20	115	14.3	48	26.7	56		42.9	2	82.6	1.6
1	25	125	15.9	54	33.4	60		50.8	2	88.9	1.6
1 1/4	32	135	17.5	64	42.2	64		63.5	2	98.4	1.6
1 1/2	40	155	19.1	70	48.3	67		73	2	114.3	1.6
2	50	165	20.7	84	60.3	68		92.1	2	127	1.6
2 1/2	65	190	23.9	100	73	75		104.8	2	149.2	1.6
3	80	210	27	117	88.9	78		127	2	168.3	1.6
3 1/2	90	230	28.6	133	101.6	79	Welding Neck bore is derived from the pipe schedule	139.7	2	184.2	1.6
4	100	255	30.2	146	114.3	84		157.2	2	200	1.6
5	125	280	33.4	178	141.3	97		185.7	2	235	1.6
6	150	320	35	206	168.3	97		215.9	2	269.9	1.6
8	200	380	39.7	260	219.1	110		269.9	2	330.2	1.6
10	250	445	46.1	321	273	116		323.8	2	387.4	1.6
12	300	520	49.3	375	323.8	129		381	2	450.8	1.6
14	350	585	52.4	425	355.6	141		412.8	2	514.4	1.6
16	400	650	55.6	483	406.4	144		469.9	2	571.5	1.6
18	450	710	58.8	533	457	157		533.4	2	628.6	1.6
20	500	775	62	587	508	160		584.2	2	685.8	1.6
24	600	915	68.3	702	610	167		692.2	2	812.8	1.6

Class 300 Weld Neck Flange Stud & Bolt Dimensions

Size in Inch	Size in mm	No of Bolts	Bolt Size UNC	Machine Bolt Length	RF Stud Length	Hole Size	ISO Stud Size	Weight in kg
1/2	15	4	1/2	55	65	5/8	M14	1.4
3/4	20	4	5/8	65	75	3/4	M16	1.4
1	25	4	5/8	65	75	3/4	M16	1.8
1 1/4	32	4	5/8	70	85	3/4	M16	2.3
1 1/2	40	4	3/4	75	90	7/8	M20	3.2
2	50	8	5/8	75	90	3/4	M16	4.1
2 1/2	65	8	3/4	85	100	7/8	M20	5.5
3	80	8	3/4	90	110	7/8	M20	6.8
3 1/2	90	8	3/4	95	110	7/8	M20	8.2
4	100	8	3/4	95	115	7/8	M20	11.4
5	125	8	3/4	110	120	7/8	M20	14.6
6	150	12	3/4	110	120	7/8	M20	19.1
8	200	12	7/8	120	140	1	M24	31
10	250	16	1	140	160	1 1/8	M27	42
12	300	16	1 1/8	145	170	1 1/4	M30	64
14	350	20	1 1/8	160	180	1 1/4	M30	82
16	400	20	1 1/4	165	190	1 3/8	M33	113
18	450	24	1 1/4	170	195	1 3/8	M33	145
20	500	24	1 1/4	185	205	1 3/8	M33	182
24	600	24	1 1/2	205	230	1 5/8	M39	264

Class 400 Weld Neck Flange Dimensions as per ASME B16.5

Size in Inch	Size in mm	Outer Diameter	Flange Thickness	Hub OD	Weld Neck OD	Welding Neck Length	Bore	RF Diameter	RF Height	PCD	Weld Face
A	B	C	D	E	F	G	H	I	J
1/2	15	95	14.3	38	21.3	52		34.9	7	66.7	1.6
3/4	20	115	15.9	48	26.7	57		42.9	7	82.6	1.6
1	25	125	17.5	54	33.4	62		50.8	7	88.9	1.6
1 1/4	32	135	20.7	64	42.2	67		63.5	7	98.4	1.6
1 1/2	40	155	22.3	70	48.3	70		73	7	114.3	1.6
2	50	165	25.4	84	60.3	73		92.1	7	127	1.6
2 1/2	65	190	28.6	100	73	79		104.8	7	149.2	1.6
3	80	210	31.8	117	88.9	83		127	7	168.3	1.6
3 1/2	90	230	35	133	101.6	86	According to Schedule	139.7	7	184.2	1.6
4	100	255	35	146	114.3	89		157.2	7	200	1.6
5	125	280	38.1	178	141.3	102		185.7	7	235	1.6
6	150	320	41.3	206	168.3	103		215.9	7	269.9	1.6
8	200	380	47.7	260	219.1	117		269.9	7	330	1.6
10	250	445	54	321	273	124		323.8	7	387.4	1.6
12	300	520	57.2	375	323.8	137		381	7	450.8	1.6
14	350	585	60.4	425	355.6	149		412.8	7	514.4	1.6
16	400	650	63.5	483	406.4	152		469.9	7	571.5	1.6
18	450	710	66.7	533	457	165		533.4	7	628.6	1.6
20	500	775	69.9	587	508	168		584.2	7	685.8	1.6
24	600	915	76.2	702	610	175		692.2	7	812.8	1.6

Class 400 Weld Neck Flange Stud & Bolt Dimesions

Size in Inch	Size in mm	No of Bolts	Bolt Size UNC	RF Stud Length	Hole Size	ISO Stud Size
1/2	15	4	1/2	75	5/8	M14
3/4	20	4	5/8	90	3/4	M16
1	25	4	5/8	90	3/4	M16
1 1/4	32	4	5/8	95	3/4	M16
1 1/2	40	4	3/4	110	7/8	M20
2	50	8	5/8	110	3/4	M16
2 1/2	65	8	3/4	120	7/8	M20
3	80	8	3/4	125	7/8	M20
3 1/2	90	8	7/8	140	1	M24
4	100	8	7/8	140	1	M24
5	125	8	7/8	145	1	M24
6	150	12	7/8	150	1	M24
8	200	12	1	170	1 1/8	M27
10	250	16	1 1/8	190	1 1/4	M30
12	300	16	1 1/4	205	1 3/8	M33
14	350	20	1 1/4	210	1 3/8	M33
16	400	20	1 3/8	220	1 1/2	M36
18	450	24	1 3/8	230	1 1/2	M36
20	500	24	1 1/2	240	1 3/4	M39
24	600	24	1 3/4	265	1 7/8	M45

Class 600 Weld Neck Flange Dimensions as per ASME B16.5

Size in Inch	Size in mm	Outer Diameter	Flange Thickness	Hub OD	Weld Neck OD	Welding Neck Length	Bore	RF Diameter	RF Height	PCD	Weld Face
A	B	C	D	E	F	G	H	I	J
1/2	15	95	14.3	38	21.3	52	According to Schedule	34.9	7	66.7	1.6
3/4	20	115	15.9	48	26.7	57	42.9	7	82.6	1.6
1	25	125	17.5	54	33.4	62	50.8	7	88.9	1.6
1 1/4	32	135	20.7	64	42.2	67	63.5	7	98.4	1.6
1 1/2	40	155	22.3	70	48.3	70	73	7	114.3	1.6
2	50	165	25.4	84	60.3	73	92.1	7	127	1.6
2 1/2	65	190	28.6	100	73	79	104.8	7	149.2	1.6
3	80	210	31.8	117	88.9	83	127	7	168.3	1.6
3 1/2	90	230	35	133	101.6	86	139.7	7	184.2	1.6
4	100	275	38.1	152	114.3	102	157.2	7	215.9	1.6
5	125	330	44.5	189	141.3	114	185.7	7	266.7	1.6
6	150	355	47.7	222	168.3	117	215.9	7	292.1	1.6
8	200	420	55.6	273	219.1	133	269.9	7	349.2	1.6
10	250	510	63.5	343	273	152	323.8	7	431.8	1.6
12	300	560	66.7	400	323.8	156	381	7	489	1.6
14	350	605	69.9	432	355.6	165	412.8	7	527	1.6
16	400	685	76.2	495	406.4	178	469.9	7	603.2	1.6
18	450	745	82.6	546	457	184	533.4	7	654	1.6
20	500	815	88.9	610	508	190	584.2	7	723.9	1.6
24	600	940	101.6	718	610	203	692.2	7	838.2	1.6

Class 600 Weld Neck Flange Stud & Bolt Dimesions

Size in Inch	Size in mm	No of Bolts	Bolt Size UNC	RF Stud Length	Hole Size	ISO Stud Size	Weight in kg
1/2	15	4	1/2	75	5/8	M14	1.5
3/4	20	4	5/8	90	3/4	M16	1.8
1	25	4	5/8	90	3/4	M16	1.8
1 1/4	32	4	5/8	95	3/4	M16	2.7
1 1/2	40	4	3/4	110	7/8	M20	3.7
2	50	8	5/8	110	3/4	M16	5.5
2 1/2	65	8	3/4	120	7/8	M20	8.2
3	80	8	3/4	125	7/8	M20	10.5
3 1/2	90	8	7/8	140	1	M24	11.8
4	100	8	7/8	145	1	M24	19.1
5	125	8	1	165	1 1/8	M27	31
6	150	12	1	170	1 1/8	M27	36
8	200	12	1 1/8	190	1 1/4	M30	55
10	250	16	1 1/4	215	1 3/8	M33	86
12	300	20	1 1/4	220	1 3/8	M33	102
14	350	20	1 3/8	235	1 1/2	M36	127
16	400	20	1 1/2	255	1 5/8	M39	177
18	450	20	1 5/8	275	1 3/4	M42	216
20	500	24	1 5/8	285	1 3/4	M42	268
24	600	24	1 7/8	330	2	M48	377

Class 900 Weld Neck Flange Dimensions as per ASME B16.5

Size in Inch	Size in mm	Outer Diameter	Flange Thickness	Hub OD	Weld Neck OD	Welding Neck Length	Bore	RF Diameter	RF Height	PCD	Weld Face
A	B	C	D	E	F	G	H	I	J
1/2	15	120	22.3	38	21.3	60		34.9	7	82.6	1.6
3/4	20	130	25.4	44	26.7	70		42.9	7	88.9	1.6
1	25	150	28.6	52	33.4	73		50.8	7	101.6	1.6
1 1/4	32	160	28.6	64	42.2	73		63.5	7	111.1	1.6
1 1/2	40	180	31.8	70	48.3	83		73	7	123.8	1.6
2	50	215	38.1	105	60.3	102		92.1	7	165.1	1.6
2 1/2	65	245	41.3	124	73	105		104.8	7	190.5	1.6
3	80	240	38.1	127	88.9	102		127	7	190.5	1.6
4	100	290	44.5	159	114.3	114		157.2	7	235	1.6
5	125	350	50.8	190	141.3	127	According to Schedule	185.7	7	279.4	1.6
6	150	380	55.6	235	168.3	140		215.9	7	317.5	1.6
8	200	470	63.5	298	219.1	162		269.9	7	393.7	1.6
10	250	545	69.9	368	273	184		323.8	7	469.9	1.6
12	300	610	79.4	419	323.8	200		381	7	533.4	1.6
14	350	640	85.8	451	355.6	213		412.8	7	558.8	1.6
16	400	705	88.9	508	406.4	216		469.9	7	616	1.6
18	450	785	101.6	565	457	229		533.4	7	685.8	1.6
20	500	855	108	622	508	248		584.2	7	749.3	1.6
24	600	1040	139.7	749	610	292		692.2	7	901.7	1.6

Class 900 Weld Neck Flange Stud & Bolt Dimesions

Size in Inch	Size in mm	No of Bolts	Bolt Size UNC	RF Stud Length	Hole Size	ISO Stud Size	Weight in kg
1/2	15	4	3/4	110	7/8	M20	2.3
3/4	20	4	3/4	115	7/8	M20	2.7
1	25	4	7/8	125	1	M24	4.1
1 1/4	32	4	7/8	125	1	M24	4.6
1 1/2	40	4	1	140	1 1/8	M27	5.9
2	50	8	7/8	145	1	M24	11.5
2 1/2	65	8	1	160	1 1/8	M27	16.5
3	80	8	7/8	145	1	M24	14
4	100	8	1 1/8	170	1 1/4	M30	23
5	125	8	1 1/4	190	1 3/8	M33	39.5
6	150	12	1 1/8	190	1 1/4	M30	50
8	200	12	1 3/8	220	1 1/2	M36	80
10	250	16	1 3/8	235	1 1/2	M36	118
12	300	20	1 3/8	255	1 1/2	M36	148
14	350	20	1 1/2	275	1 5/8	M39	182
16	400	20	1 5/8	285	1 3/4	M42	225
18	450	20	1 7/8	325	2	M48	300
20	500	20	2	350	2 1/8	M52	373
24	600	20	2 1/2	440	2 5/8	M64	680

Class 1500 Weld Neck Flange Dimensions as per ASME B16.5

Size in Inch	Size in mm	Outer Diameter	Flange Thickness	Hub OD	Weld Neck OD	Welding Neck Length	Bore	RF Diameter	RF Height	PCD	Weld Face
A	B	C	D	E	F	G	H	I	J
1/2	15	120	22.3	38	21.3	60		34.9	7	82.6	1.6
3/4	20	130	25.4	44	26.7	70		42.9	7	88.9	1.6
1	25	150	28.6	52	33.4	73		50.8	7	101.6	1.6
1 1/4	32	160	28.6	64	42.2	73		63.5	7	111.1	1.6
1 1/2	40	180	31.8	70	48.3	83		73	7	123.8	1.6
2	50	215	38.1	105	60.3	102		92.1	7	165.1	1.6
2 1/2	65	245	41.3	124	73	105		104.8	7	190.5	1.6
3	80	265	47.7	133	88.9	117		127	7	203.2	1.6
4	100	310	54	162	114.3	124	According to Schedule	157.2	7	241.3	1.6
5	125	375	73.1	197	141.3	156		185.7	7	292.1	1.6
6	150	395	82.6	229	168.3	171		215.9	7	317.5	1.6
8	200	485	92.1	292	219.1	213		269.9	7	393.7	1.6
10	250	585	108	368	273	254		323.8	7	482.6	1.6
12	300	675	123.9	451	323.8	283		381	7	571.5	1.6
14	350	750	133.4	495	355.6	298		412.8	7	635	1.6
16	400	825	146.1	552	406.4	311		469.9	7	704.8	1.6
18	450	915	162	597	457	327		533.4	7	774.7	1.6
20	500	985	177.8	641	508	356		584.2	7	831.8	1.6
24	600	1170	203.2	762	610	406		692.2	7	990.6	1.6

Class 1500 Weld Neck Flange Stud & Bolt Dimesions

Size in Inch	Size in mm	No of Bolts	Bolt Size UNC	RF Stud Length	Hole Size	ISO Stud Size	Weight in kg
1/2	15	4	3/4	110	7/8	M20	2.3
3/4	20	4	3/4	115	7/8	M20	2.7
1	25	4	7/8	125	1	M24	4.1
1 1/4	32	4	7/8	125	1	M24	4.6
1 1/2	40	4	1	140	1 1/8	M27	5.9
2	50	8	7/8	145	1	M24	11.4
2 1/2	65	8	1	160	1 1/8	M27	16.4
3	80	8	1 1/8	180	1 1/4	M30	21.8
4	100	8	1 1/4	195	1 3/8	M33	33
5	125	8	1 1/2	250	1 5/8	M39	59
6	150	12	1 3/8	260	1 1/2	M36	75
8	200	12	1 5/8	290	1 3/4	M42	125
10	250	12	1 7/8	335	2	M48	207
12	300	16	2	375	2 1/8	M52	314
14	350	16	2 1/4	405	2 3/8	M56	427
16	400	16	2 1/2	445	2 5/8	M64	568
18	450	16	2 3/4	495	2 7/8	M72	738
20	500	16	3	540	3 1/8	M76	932
24	600	16	3 1/2	615	3 5/8	M90	1511

Class 2500 Weld Neck Flange Dimensions as per ASME B16.5

Size in Inch	Size in mm	Outer Diameter	Flange Thickness	Hub OD	Weld Neck OD	Welding Neck Length	Bore	RF Diameter	RF Height	PCD	Weld Face
A	B	C	D	E	F	G	H	I	J
1/2	15	135	30.2	43	21.3	73		34.9	7	88.9	1.6
3/4	20	140	31.8	51	26.7	79		42.9	7	95.2	1.6
1	25	160	35	57	33.4	89		50.8	7	108	1.6
1 1/4	32	185	38.1	73	42.2	95		63.5	7	130.2	1.6
1 1/2	40	205	44.5	79	48.3	111		73	7	146	1.6
2	50	235	50.9	95	60.3	127	According to Schedule	92.1	7	171.4	1.6
2 1/2	65	265	57.2	114	73	143		104.8	7	196.8	1.6
3	80	305	66.7	133	88.9	168		127	7	228.6	1.6
4	100	355	76.2	165	114.3	190		157.2	7	273	1.6
5	125	420	92.1	203	141.3	229		185.7	7	323.8	1.6
6	150	485	108	235	168.3	273		215.9	7	368.3	1.6
8	200	550	127	305	219.1	318		269.9	7	438.2	1.6
10	250	675	165.1	375	273	419		323.8	7	539.8	1.6
12	300	760	184.2	441	323.8	464		381	7	619.1	1.6

Class 2500 Weld Neck Flange Stud & Bolt Dimesions

Size in Inch	Size in mm	No of Bolts	Bolt Size UNC	RF Stud Length	Hole Size	ISO Stud Size	Weight in kg
1/2	15	4	3/4	120	7/8	M20	3.3
3/4	20	4	3/4	125	7/8	M20	3.7
1	25	4	7/8	140	1	M24	5.5
1 1/4	32	4	1	150	1 1/8	M27	7.8
1 1/2	40	4	1 1/8	170	1 1/4	M30	11.5
2	50	8	1	180	1 1/8	M27	19
2 1/2	65	8	1 1/8	195	1 1/4	M30	24
3	80	8	1 1/4	220	1 3/8	M33	42.8
4	100	8	1 1/2	255	1 5/8	M39	66
5	125	8	1 3/4	300	1 7/8	M45	111
6	150	8	2	345	2 1/8	M52	173
8	200	12	2	380	2 1/8	M52	264
10	250	12	2 1/2	490	2 5/8	M64	490
12	300	12	2 3/4	540	2 7/8	M72	695

Weld Neck Flange Weight Chart

Flange Size (inches)	Class 150 (lbs)	Class 300 (lbs)	Class 400 (lbs)	Class 600 (lbs)	Class 900 (lbs)	Class 1500 (lbs)	Class 2500 (lbs)
½	2	2	3	3	7	7	8
¾	2	3	3.5	4	7	7	9
1	3	4	4	4	8.5	8.5	13
1¼	3	5	4.5	6	10	10	20
1½	4	7	8	8	14	14	28
2	6	9	10	12	24	24	42
2½	10	12	14	18	31	31	52
3	11.5	18	18	23	36	36	94
3½	12	20	26	26	53	53	146
4	16.5	26.5	35	42	86	86	244
5	21	36	43	68	110	110	378
6	26	45	57	81	187	187	576
8	42	69	89	120	268	268	1068
10	54	100	125	190	372	372	1608
12	88	142	175	226	562	562	–
14	114	206	233	347	685	685	–
16	140	250	295	481	924	924	–
18	165	320	360	555	1164	1164	–
20	197	400	445	690	2107	2107	–
22	225	465	505	720	–	–	–
24	268	580	640	977	–	–	–

Weld Neck Flange Tolerance

Dimension	Tolerance
Outside Diameter (OD)	±1/16 in for ODs up to 24 in
	±1/8 in for ODs over 24 in
Inside Diameter (ID)	±1/32 in for diameters up to 10 in
	+1/16 in for diameters 12-18 in
	+1/8 in, -1/16 in for diameters over 20 in
Diameter of Contact Face	1/16 in
Raised Face	±1/32 in
Tongue and Groove or Male and Female	±1/64 in
Diameter of Hub at Point of Welding	+3/32 in, -1/32 in for hubs up to 5 in
	+5/32 in, -1/32 in for hubs over 6 in
Diameter of Hub at Base	±1/16 in for hub bases up to 24 in
	±1/8 in for hub bases over 24 in
Bolt Circle	±1/16 in
Bolt Hole Spacing	+1/32 in
Eccentricity of Bolt Circle and Facing	1/32 in max
Length Thru Hub	±1/16 in for lengths up to 10 in
	±1/8 in for lengths over 12 in
Thickness	+1/8 in, -0 in for thicknesses up to 18 in
	+3/16 in, -0 in for thicknesses over 20 in

Flange Face Types

Raised Face (RF): Provides a better seal and is most common for process applications.
Flat Face (FF): Used for low-pressure and non-critical applications.
Ring Type Joint (RTJ): Designed for high-pressure and high-temperature applications.
Male and Female (M&F): Used in specialized applications requiring alignment.
Tongue and Groove (T&G): Ensures precise mating for critical joints.

Standards

ASME B16.5: For pipe flanges and flanged fittings (sizes up to 24″).
ASME B16.47: For large-diameter flanges (sizes above 24″).
API 605: Applicable for large-diameter steel flanges.
MSS SP-44: For pipeline flanges.
DIN EN 1092-1: European standard for steel flanges.
ISO 7005-1: International standard for metallic flanges.

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Class 150 Weld Neck Flange Dimensions

Class 150 Weld Neck Flange Stud & Bolt Dimensions

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Class 300 Weld Neck Flange Stud & Bolt Dimensions

Class 400 Weld Neck Flange Dimensions as per ASME B16.5

Class 400 Weld Neck Flange Stud & Bolt Dimesions

Class 600 Weld Neck Flange Dimensions as per ASME B16.5

Class 600 Weld Neck Flange Stud & Bolt Dimesions

Class 900 Weld Neck Flange Dimensions as per ASME B16.5

Class 900 Weld Neck Flange Stud & Bolt Dimesions

Class 1500 Weld Neck Flange Dimensions as per ASME B16.5

Class 1500 Weld Neck Flange Stud & Bolt Dimesions

Class 2500 Weld Neck Flange Dimensions as per ASME B16.5

Class 2500 Weld Neck Flange Stud & Bolt Dimesions

Weld Neck Flange Weight Chart

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