Weld Neck Flanges | ASME B16.5 | ASME B16.47

PM Industries manufactures, supplies, and stocks Weld Neck Flanges in a range of materials, pressure classes, and pipe sizes. A weld neck flange has a long tapered hub that transitions smoothly from the flange body down to the pipe wall thickness. The pipe is butt-welded to the end of the hub with a full-penetration weld. That butt weld is the strongest and most inspectable pipe-to-flange connection available in standard flange types, which is why weld neck flanges are the default specification for high-pressure, high-temperature, and critical service piping.

The tapered hub is the structural feature that separates weld neck flanges from slip-on, socket weld, and threaded alternatives. As pressure, temperature, or mechanical load acts on the flanged joint, the stresses at the weld and at the pipe-to-flange transition are distributed gradually through the hub taper rather than concentrated at a sharp section change. That stress distribution means weld neck flanges perform better under fatigue loading, thermal cycling, and mechanical stress than any other standard flange attachment type.

Full-penetration weld inspectability is the quality assurance advantage that matters most in critical service. A slip-on flange's fillet welds can be visually and dye-penetrant examined, but they can't be radiographed to verify internal soundness. A weld neck butt weld can. In high-pressure service, sour gas service to NACE MR0175, and other critical piping where weld inspection requirements are part of the quality plan, the butt-welded weld neck flange is the only standard attachment that satisfies the full inspection requirement without additional engineering justification.

Hub bore matching to pipe schedule is a practical fit-up consideration. Weld neck flanges are produced to match specific pipe schedules, so the hub bore inside diameter matches the pipe inside diameter at the weld. Mismatched bore and pipe ID creates an internal step at the weld that increases turbulence in flow-sensitive applications and creates a stress concentration under pressure loading. Confirming that the flange hub schedule matches the pipe wall schedule is a basic but sometimes overlooked step in procurement.

High-temperature alloy steel weld neck flanges for power generation service deserve attention at fabrication. Grades F11, F22, and especially F91 (9Cr-1Mo-V) require preheat, controlled interpass temperature, and post-weld heat treatment per the applicable ASME code requirements and welding procedure specification. Skipping or shortcutting those controls produces welds that pass visual inspection but fail under creep loading at operating temperature. PM Industries supplies these grades with full material certification and can provide material data sheets supporting the required welding procedure development.

Weld neck flanges are available with full material certification to ASTM, ASME, API, and applicable specifications including NACE MR0175/ISO 15156 for sour service and low-temperature impact testing where required. Contact PM Industries for material selection, hub schedule, pressure class, face type, and pricing.

Specification Weld Neck Flange

Standards	ANSI/ASME B16.5, B16.48, GOST, DIN, EN-1092, B16.47 Series A & B, AWWA, BS Flanges
JIS Standard	5K, 10K, 16K, 20K, 30K, 40K, 63K
DIN Flanges	DIN 2527, 2627, 2631, 2656, 2576, 2673, 2629, 2628, 2566

Flanges are Available in Following Materials

Stainless Steel	SS 201, SS 202, SS 301, SS 304, SS 304L, SS 310, SS 310S, SS 316L, SS 316TI, SS 317, SS 317L, SS 321, SS 347, SS 409, SS 409M, SS 409L, SS 410, SS 410S, SS 420, SS 430, SS 431, SS 441, SS 444, SS 446, SS 17-4PH, SS 904L.
Duplex Steel	UNS S32205, UNS S31803 Flange
Super Duplex Steel	UNS S32750, UNS S32760 Flanges
Carbon Steel	Carbon steel A105 Flanges, A36 Flanges, IS 2062 Flanges, A350 LF2 Flanges, F42 Flanges, F52 Flanges, F56 Flanges, F60 Flanges, F65 Flanges, F70 Flanges, F80 Flanges, IBR flanges, A694 Flanges, SS400, SF440, ST37-2 Flanges, S235JrG2 Flanges, P250GH Flanges, C22.8 Flanges, etc.
Alloys Steel	Alloy 20, F1, F5, F9, F11, F22, F91 Flanges
Copper Alloys	Cu-Ni 70/30, Cu-Ni 90/10, C 24000, C 75700, C 51100, C 22000, C 27200, C 21000, C 26800, C 52100, C 77000, C 52000, C 11000, C 74500, C 23000, C 28000, C 12200, C 76400, C 51900, C 75400, C 26000, C 51000, C 10200, C 27000
Nickel Alloys	Nickel 200, 201
Inconel	Inconel 600, 601, 625, 718, 800, 825, X-750
Monel	Monel 400, k500
Hastelloy	Hastelloy C-22, C-276, C-4, X
Titanium	Grade 1, 4, 5(Ti 6Al-4V), 6(Ti 5Al-2.5Sn), 7, 11, 6Al-2Sn-4Zr-2Mo, Grade 12, 6Al-6V-25n, Grade 23(Ti 6AL-4V ELI), 8Ai-1Mo-1V, Grade 5 ELI, Grade 9(3Al-2.5V), 6Al-7Nb.
Aluminium	6063, 1100, 6082 A96082, 1050, 2017, 2024 A92024, 7050 A97050, 5083 A95083, 2014A A92014, 2011 A92011, 6061 A96061 A86061, 5754, 7085, 2050, 7071 7020, 7178, 5052 A95052, 7150, 7075 A97075 A87075, 7575, 2219, 7175
Pressure Rating	Class 150 LBS, 300 LBS, 600 LBS, 900 LBS, 1500 LBS, 2500 LBS
Types	Threaded, Plate, Screwed, Forged.
Supporting material	Gasket, Ring Joint, Flange Bolts
Size range	1/2" (15 NB) to 48" (1200NB) DN10~DN5000
High Temperature	Above 200°C (400°F) For Class 150 Or Above 400°C (750°F)
Low Temperature	Above -29 Degree C (−20°F)
Production technique	Forged, machined and Heat treated
Custom design	As per your drawing
Origin	Indian / USA / Korean / West Europe / Japan
Pressure Class	PN 6 TO PN 100
Coating/Surface Treatment:	Zinc Plated, Anti-rust Paint, Oil Black Paint, Yellow Transparent, Cold and Hot Dip Galvanized.
European/African/Russian Standard Flanges	Available
Test	Direct-reading Spectrograph, X-ray detector, UItrasonic flaw detector, Magnetic particle detector, Hydrostatic testing machine.
Marking Standard	Name of Manufacturer
	Schedule
	Type of Flange Facing
	Pressure Class
	Nominal Pipe Size, etc
Test Certificates	EN 10204/3.1B, NACE MR0103, NACE MR0175
	Raw Materials Certificate
	100% Radiography Test Report
	Third Party Inspection Report, etc

Raised Face WNRF Flange 150# Dimensions

ø in Inch	D	b	g	m	a	J*	h	k	Holes	l	Kg.
5	254,0	23,8	185,7	163,5	141,2	128,3	88,9	215,9	8	22,2	9,200
3/4	98,4	12,7	42,9	38,1	26,7	20,8	52,4	69,8	4	15,9	0,700
1	107,9	14,3	50,8	49,2	33,5	26,7	55,6	79,4	4	15,9	1,100
1 1/4	117,5	15,9	63,5	58,8	42,2	35,1	57,1	88,9	4	15,9	1,500
1 1/2	127,0	17,5	73,0	65,1	48,3	40,9	61,9	98,4	4	15,9	1,800
1/2	88,9	11,1	34,9	30,2	21,3	15,7	47,6	60,3	4	15,9	0,500
2	152,4	19,0	92,1	77,8	60,3	52,6	63,5	120,6	4	19,0	2,700
2 1/2	177,8	22,2	104,8	90,5	73,1	62,7	69,8	139,7	4	19,0	4,400
3	190,5	23,8	127,0	107,9	88,9	78,0	69,8	152,4	4	19,0	5,200
3 1/2	215,9	23,8	139,7	122,2	101,6	90,2	71,4	177,8	8	19,0	6,400
4	228,6	23,8	157,2	134,9	114,3	102,4	76,2	190,5	8	19,0	7,500
6	279,4	25,4	215,9	192,1	168,4	154,2	88,9	241,3	8	22,2	11,000
8	342,9	28,6	269,9	246,1	219,1	202,7	101,6	298,4	8	22,2	18,300
10	406,4	30,2	323,8	304,8	273,0	254,5	101,6	361,9	12	25,4	25,000
12	482,6	31,7	381,0	365,1	323,8	304,8	114,3	431,8	12	25,4	39,000
14	533,4	34,9	412,7	400,0	355,6	336,5	127,0	476,2	12	28,6	51,000
16	596,9	36,5	469,9	457,2	406,4	387,3	127,0	539,7	16	28,6	60,000
18	635,0	39,7	533,4	504,8	457,2	438,1	139,7	577,8	16	31,7	71,000
20	698,5	42,9	584,2	558,8	508,0	488,9	144,5	635,0	20	31,7	88,000
22	749,3	46,0	641,2	609,6	558,8	539,7	149,2	692,1	20	34,9	102,000
24	812,8	47,6	692,1	663,6	609,6	590,5	152,4	749,3	20	34,9	119,000

Welding Neck Flange Class 300 Dimensions

ø in inches	D	b	g	m	a	J*	h	k	Holes	l	Kg.
14	584,2	54,0	412,7	425,4	355,6	336,5	142,9	514,3	20	31,7	88,000
1/2	95,2	14,3	34,9	38,1	21,3	15,7	52,4	66,7	4	15,9	0,900
3/4	117,5	15,9	42,9	47,6	26,7	20,8	57,1	82,5	4	19,0	1,500
1	123,8	17,5	50,8	54,0	33,5	26,7	61,9	88,9	4	19,0	1,900
1 1/4	133,3	19,0	63,5	63,5	42,2	35,1	65,1	98,4	4	19,0	2,600
1 1/2	155,6	20,6	73,0	69,8	48,3	40,9	68,3	114,3	4	22,2	3,300
2	165,1	22,2	92,1	84,1	60,3	52,6	69,8	127,0	8	19,0	3,600
2 1/2	190,5	25,4	104,8	100,0	73,1	62,7	76,2	149,2	8	22,2	5,400
3	209,5	28,6	127,0	117,5	88,9	78,0	79,4	168,3	8	22,2	7,400
4	254,0	31,7	157,2	146,0	114,3	102,4	85,7	200,0	8	22,2	11,900
5	279,4	34,9	185,7	177,8	141,2	128,3	98,4	234,9	8	22,2	16,000
6	317,5	36,5	215,9	206,4	168,4	154,2	98,4	269,9	12	22,2	20,200
3 1/2	228,6	30,2	139,7	133,3	101,6	90,2	81,0	184,1	8	22,2	8,900
8	381,0	41,3	269,9	260,3	219,1	202,7	111,1	330,2	12	25,4	31,000
10	444,5	47,6	323,4	320,7	273,0	254,5	117,5	387,3	16	28,6	44,300
12	520,7	50,8	381,0	374,6	323,8	304,8	130,2	450,8	16	31,7	64,000
16	647,7	57,1	469,9	482,6	406,4	387,3	146,0	571,5	20	34,9	113,000
18	711,2	60,3	533,4	533,4	457,2	438,1	158,7	628,6	24	34,9	134,000
20	774,7	63,5	584,2	587,4	508,0	488,9	161,9	685,8	24	34,9	171,000
22	838,2	66,7	641,2	641,2	558,8	539,7	165,1	742,9	24	41,3	195,000
24	914,4	69,8	692,1	701,7	609,6	590,5	168,3	812,8	24	41,3	238,000

Weld Neck Flange Class 600 Dimensions

ø In Inches	D	b	g	m	J	h	k	Holes	l	Kg.
14	603,2	69,8	412,7	431,8	359,1	93,7	527,0	20	38,1	100,000
1/2	95,2	14,3	34,9	38,1	22,3	22,2	66,7	4	15,9	0,800
3/4	117,5	15,9	42,9	47,6	27,7	25,4	82,5	4	19,0	1,400
1	123,8	17,5	50,8	54,0	34,5	27,0	88,9	4	19,0	1,600
5	330,2	44,4	185,7	188,9	143,8	60,3	266,7	8	28,6	24,500
1 1/2	155,6	22,2	73,0	69,8	49,5	31,7	114,3	4	22,2	3,100
2	165,1	25,4	92,1	84,1	62,0	36,5	127,0	8	19,0	3,700
2 1/2	190,5	28,6	104,8	100,0	74,7	41,3	149,2	8	22,2	5,400
3	209,5	31,7	127,0	117,5	90,7	46,0	168,3	8	22,2	7,300
3 1/2	228,6	34,9	139,7	133,3	103,4	49,2	184,1	8	25,4	8,900
4	273,0	38,1	157,2	152,4	116,1	54,0	215,9	8	25,4	11,800
6	355,6	47,6	215,9	222,2	170,7	66,7	292,1	12	28,6	29,500
1 1/4	133,3	20,6	63,5	63,5	43,2	28,6	98,4	4	19,0	2,100
8	419,1	55,6	269,9	273,0	221,5	76,2	349,2	12	31,7	43,000
12	558,8	66,7	381,0	400,0	327,1	92,1	488,9	20	34,9	86,000
16	685,8	76,2	469,9	495,3	410,5	106,4	603,2	20	41,3	142,000
18	742,9	82,5	533,4	546,1	461,8	117,5	654,0	20	44,4	175,000
20	812,8	88,9	584,2	609,6	513,1	127,0	723,9	24	44,4	232,000
22	869,9	95,2	641,2	666,7	564,4	133,3	777,9	24	47,6	292,000
10	508,0	63,5	323,8	342,8	276,3	85,7	431,8	16	34,9	70,000
24	939,8	101,6	692,1	717,5	615,9	139,7	838,2	24	50,8	330,000

Class 900 WNRF Flange Dimensions In Mm

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	Refer Note	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		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

Weld Neck Flange Dimensions 1500#

Size in Inch	Size in mm	Outer diameter	Flange thickness	Hub Outer diameter	Weld Neck OD	Welding Neck Length	Bore	Raised Face Diameter	Raised Face Height	PCD	Weld Face
A	B	C	D	E	F	G	H	I	J
1/2	15	120	22.3	38	21.3	60	Refer Note	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
2	50	215	38.1	105	60.3	102		92.1	7	165.1	1.6
8	200	485	92.1	292	219.1	213		269.9	7	393.7	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
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
4	100	310	54	162	114.3	124		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
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
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
14	350	750	133.4	495	355.6	298		412.8	7	635	1.6
24	600	1170	203.2	762	610	406		692.2	7	990.6	1.6

Reducing Weld Neck Flange Dimensions Class 2500

Size in Inch	Size in mm	Outer Diameter	Flange Thickness	Hub Outer diameter	Weld Neck Outer diameter	Welding Neck Length	Bore	Raised Face Diameter	Raised Face Height	PCD	Weld Face
A	B	C	D	E	F	G	H	I	J
1/2	15	135	30.2	43	21.3	73	Refer Note	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 1/4	32	185	38.1	73	42.2	95		63.5	7	130.2	1.6
12	300	760	184.2	441	323.8	464		381	7	619.1	1.6
2	50	235	50.9	95	60.3	127		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
1	25	160	35	57	33.4	89		50.8	7	108	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
1 1/2	40	205	44.5	79	48.3	111		73	7	146	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

Jis Welding Neck Flange Dimension Standard

Nominal	Outside	Inside	Outside	Sectional Dimensions of Flange							Bolt Hole			Nominal	Approx.
Dia. of	Dia. of	Dia. of	Dia. of	t	T	Dia. of Hub		r	Dia. of	Dia. of	Bolt.	Number	Hole	Bolt	Weight
Flange	Steel	Flange	Flange			a	b		Face	Raised Face	Circle	of Bolt	Dia.	Size	(kg)
	Pipe	do	D						f	g	Dia	Holes	h	BL	SOH
10	17.3	17.8	90	12	16	26	28	4	1	46	65	4	15	M12	0.53	0.52
15	21.7	22.2	95	12	16	30	32	4	1	51	70	4	15	M12	0.6	0.58
20	27.2	27.7	100	14	20	38	42	4	1	56	75	4	15	M12	0.79	0.75
32	42.7	43.2	135	16	22	56	60	5	2	76	100	4	19	M16	1.66	1.53
40	48.6	49.1	140	16	24	62	66	5	2	81	105	4	19	M16	1.79	1.64
50	60.5	61.1	155	16	24	76	80	5	2	96	120	8	19	M16	2.09	1.83
65	76.3	77.1	175	18	26	94	98	5	2	116	140	8	19	M16	3.08	2.58
80	89.1	90	200	20	28	108	112	6	2	132	160	8	23	M20	4.41	3.61
25	34	34.5	125	14	20	46	50	4	1	67	90	4	19	M16	1.22	1.16
-90	101.6	102.6	210	20	30	120	124	6	2	145	170	8	23	M20	4.92	3.89
100	114.3	115.4	225	22	34	134	138	6	2	160	185	8	23	M20	6.29	4.87
125	139.8	141.2	270	22	34	164	170	6	2	195	225	8	25	M22	9.21	7.09
200	216.3	218	350	26	40	244	252	6	2	275	305	12	25	M22	18.4	12
250	267.4	269.5	430	28	44	304	312	6	2	345	380	12	27	M24	30.4	20.1
300	318.5	321	480	30	48	354	364	8	3	395	430	16	27	M24	40.5	24.3
150	165.2	166.6	305	24	38	196	202	6	2	230	260	12	25	M22	12.7	9.57
350	355.6	358.1	540	34	52	398	408	8	3	440	480	16	33	M30×3	57.5	34.4
400	406.4	409	605	38	60	446	456	10	3	495	540	16	33	M30×3	81.7	47.4
450	457.2	460	675	40	64	504	514	10	3	560	605	20	33	M30×3	107	61.8
500	508	511	730	42	68	558	568	10	3	615	660	20	33	M30×3	132	73.7
600	609.6	613	845	46	74	666	676	10	3	720	770	24	39	M36×3	192	98.4
650	660.4	664	895	48	77	704	726	10	5	770	820	24	39	M36×3	–	–
700	711.2	715	960	50	80	754	776	10	5	820	875	24	42	M39×3	–	–
750	762	766	1020	52	83	806	832	10	5	880	935	24	42	M39×3	–	–
-550	558.8	562	795	44	70	612	622	10	3	670	720	20	39	M36×3	163	87.9
800	812.8	817	1085	54	86	865	885	10	5	930	990	24	48	M45×3	–	–
850	863.6	868	1135	56	89	916	936	10	5	980	1040	24	48	M45×3	–	–
1000	1016	1021	1320	62	99	1070	1098	12	5	1140	1210	28	56	M52×3	–	–
1100	1117.6	1123	1420	66	105	1180	1200	12	15	1240	1310	32	56	M52×3	–	–
1200	1219.2	1225	1530	70	112	1282	1302	12	5	1350	1420	32	56	M52×3
1300	1320.8	1326	1645	74					5	1450	1530	32	62	M56×3
900	914.4	919	1185	58	93	968	986	10	5	1030	1090	28	48	M45×3	–	–
1350	1371.6	1377	1700	76					5	1510	1590	32	62	M56×3
1400	1422.4	1428	1755	78					5	1560	1640	36	62	M56×3
1500	1524	1529	1865	80					5	1670	1750	36	62	M56×3

Weld Neck Flange Schedule Chart

Nom Pipe Size	Outside Diam	Sched 10	Sched 20	Sched 30	Std. Wall	Sched 40	Sched 60	Extra Strong	Sched 80	Sched 100	Sched 120	Sched 140	Sched 160	Double Extra Strong
1/2”	0.840	0.674	–	–	0.622	0.622	–	0.546	0.546	–	–	–	0.464	0.252
1”	1.315	1.097	–	–	1.049	1.049	–	0.957	0.957	–	–	–	0.815	0.599
1.1/4”	1.660	1.442	–	–	1.380	1.380	–	1.278	1.278	–	–	–	1.160	0.896
1.1/2”	1.900	1.682	–	–	1.610	1.610	–	1.500	1.500	–	–	–	1.338	1.100
2”	2.375	2.157	–	–	2.067	2.067	–	1.939	1.939	–	–	–	1.687	1.503
3/4”	1.050	0.884	–	–	0.824	0.824	–	0.742	0.742	–	–	–	0.612	0.434
2.1/2”	2.875	2.635	–	–	2.469	2.469	–	2.323	2.323	–	–	–	2.125	1.771
3”	3.500	3.260	–	–	3.068	3.068	–	2.900	2.900	–	–	–	2.624	2.300
3-1/2”	4.000	3.760	–	–	3.548	3.548	–	3.364	3.364	–	–	–	–	2.728
4”	4.500	4.260	–	–	4.026	4.026	–	3.826	3.826	–	3.624	–	3.438	3.152
6”	6.625	6.357	–	–	6.065	6.065	–	5.761	5.761	–	5.501	–	5.187	4.897
8”	8.625	8.329	8.125	8.071	7.981	7.981	7.813	7.625	7.625	7.437	7.187	7.001	6.813	6.875
5”	5.563	5.295	–	–	5.047	5.047	–	4.813	4.813	–	4.563	–	4.313	4.063
10”	10.750	10.420	10.250	10.136	10.020	10.020	9.750	9.750	9.562	9.312	9.062	8.750	8.500	8.750
14”	14.000	13.500	13.376	13.250	13.250	13.124	12.812	13.000	12.500	12.124	11.814	11.500	11.188	–
16”	16.000	15.500	15.376	15.250	15.250	15.000	14.688	15.000	14.312	13.938	13.564	13.124	12.812	–
18”	18.000	17.500	17.376	17.124	17.250	16.876	16.500	17.000	16.124	15.688	15.250	14.876	14.438	–
12”	12.750	12.390	12.250	12.090	12.000	11.938	11.626	11.750	11.374	11.062	10.750	10.500	10.126	10.750
20”	20.000	19.500	19.250	19.000	19.250	18.812	18.376	19.000	17.938	17.438	17.000	16.500	16.062	–
24”	24.000	23.500	23.250	22.876	23.250	22.624	22.062	23.000	21.562	20.938	20.376	19.876	19.312	–
30”	30.000	29.376	29.000	28.750	29.250	–	–	29.000	–	–	–	–	–	–
42”	42.000	–	–	–	41.250	–	–	41.000	–	–	–	–	–	–
36”	36.000	35.376	35.000	34.750	35.250	34.500	–	35.000	–	–	–	–	–	–

SS WNRF Flange Weight Chart

Nom Pipe Size	Class 150LBS			Class 300LBS			Class 600LBS			Class 900LBS			Class 1500LBS			Class 2500LBS
	Weld Neck	Slip On	Blind	Weld Neck	Slip On	Blind	Weld Neck	Slip On	Blind	Weld Neck	Slip On	Blind	Weld Neck	Slip On	Blind	Weld Neck	Slip On	Blind
1/2”	0.7	0.4	0.5	0.8	0.7	0.8	0.9	0.8	0.8	2.1	1.8	1.9	2.1	1.8	1.9	3.2	3	3
3”	5.2	3.8	5.1	7.3	5.9	7.2	8.7	7.3	8.9	15	12.3	16.8	21	21.5	19.5	42.6	38	39
1”	1.1	0.8	0.9	1.7	1.4	1.5	1.9	1.7	1.7	3.9	3.6	3.7	3.9	3.6	3.7	5.4	5	5
1.1/4”	1.5	1.2	1.3	2.2	1.8	2	2.6	2.1	2.4	4.5	4.1	4.3	4.5	4.1	4.3	7.8	8	8
1.1/2”	1.8	1.4	1.6	3.2	2.7	2.9	3.6	3.1	3.4	6.2	5.4	5.9	6.2	5.4	5.9	11.5	11	11
2”	2.7	2.2	2.6	3.6	3.2	3.5	4.7	3.9	4.4	11.3	10.5	11.3	11.3	10.5	11.3	19	17	17
3/4”	0.8	0.7	0.8	1.4	1.2	1.2	1.6	1.4	1.4	2.7	2.4	2.7	2.7	2.4	2.7	3.6	4	4.5
3-1/2”	6.4	5	6.5	8.9	7.5	9.2	11.6	9	12.7
4”	7.5	5.6	7.5	11.8	10	12.2	18.4	16.5	18.6	24	23.2	24.5	31.8	31	33	64	58	60
5”	9.2	6.5	9.2	16	12.5	16	31	28.5	30.8	38.5	37.5	39.5	59	58.8	60	111	95	101
6”	11.0	8.1	11.8	20.2	16.5	22	37	36.2	38	50	48.3	51.5	72	74	75	171	146	156
2.1/2”	4.4	3.5	4.1	5.4	4.5	5.3	4.8	5.4	6.8	16.3	15.8	16	16.3	15.8	16	24	25	25
8”	18.4	13	20.4	31.2	25.5	36	54.5	51.5	62.2	85	75	89	124	112	125	261	220	242
10”	25.5	18.4	31	44.3	35	55	98.5	76.2	102	123	110	131	207	184	215	485	420	465
12”	37	28.5	47	63.5	52	82.5	105	89.5	132	168	146	187	306	264	316	698	590	665
14”	51	37.5	60	86	73	108	150	102	158	198	172	224	416
18”	71.5	54	93	141	115	178	228	180	285	318	272	383	736
20”	85	72	127	173	139	228	285	231	365	376	330	482	929
24”	119	95	190	248	212	350	372	330	532	680	632	905	1504
16”	61.5	44.5	61	112	88	139	177	150	225	225	192	259	567

Stainless Steel Weld Neck Flange Pressure Ratings

Temperature °F	Class 150 LBS	Class 300 LBS	Class 400 LBS	Class 600 LBS	Class 900 LBS	Class 1500 LBS	Class 2500 LBS
-20 to 100	275	720	960	1440	2160	3600	6000
300	215	560	745	1120	1680	2795	4660
1300	20	115	155	235	350	585	970
400	195	515	685	1025	1540	2570	4280
500	170	480	635	955	1435	2390	3980
600	140	450	600	900	1355	2255	3760
650	125	445	590	890	1330	2220	3700
1500	20	40	55	85	125	205	345
700	110	430	580	870	1305	2170	3620
1050	20	345	460	685	1030	1720	2865
200	235	620	825	1240	1860	3095	5160
750	95	425	570	855	1280	2135	3560
800	80	420	565	845	1265	2110	3520
850	65	420	555	835	1255	2090	3480
900	50	415	555	830	1245	2075	3460
950	35	385	515	775	1160	1930	3220
1000	20	350	465	700	1050	1750	2915
1100	20	305	405	610	915	1525	2545
1150	20	235	315	475	710	1185	1970
1200	20	185	245	370	555	925	1545
1250	20	145	195	295	440	735	1230
1350	20	95	130	190	290	480	800
1400	20	75	100	150	225	380	630
1450	20	60	80	115	175	290	485

Weld Neck Flange Tolerances

Dimension	Flange	Tolerance
A	Outside Diameter	When O.D. is 24" or less: ±1/16" (1.6mm) When O.D. is over 24": ±1/8" (3.2mm)
D	Inside Diameter	10" and smaller: ±1/32" (0.8mm) 12" thru 18": +1/8" (3.2mm) 20" and larger: -1/16" (1.6mm)
B	Diameter of contact face	1/16" raised face: ±1/32" (0.8mm) 1/4" Raised Face, Tongue & Groove (male & female): ±1/64" (0.4mm)
J	Diameter of hub at base	When hub base is 24" or smaller: ±1/16" (1.6mm) When hub base is over 24": ±1/8" (3.2mm)
H	Diameter of hub at point of welding	5" and smaller: +3/32" (2.4mm), -1/32" (0.8mm) 6" and larger: +5/32" (4.0mm), -1/32 (0.8mm)
P	Drilling	Bolt circle: ±1/16" (1.6mm) Bolt hole spacing: ±1/32" (0.8mm)
	Eccentricity of bolt circle with respect to facing	2 1/2" and smaller ±1/32" (0.8mm) max. 3" and larger ±1/16" (1.6mm) max.
C	Thickness	18" and smaller: ±1/8" (3.2mm), -0" 20" and larger: ±3/16" (4.8mm), -0"
K	Length of hub	10" and smaller: ±1/16" (1.6mm) 12" and larger: ±1/8" (3.2mm)