A350 LF6 Flanges | ASTM A350 | ASME B16.5

PM Industries manufactures, supplies, and stocks ASTM A350 LF6 flanges, high-performance forged flanges built for low-temperature service where strength, toughness, and reliability all matter. Made to ASTM A350, these flanges go into carbon and low-alloy steel piping that has to run safely in sub-zero conditions. That suits oil and gas pipelines, LNG plants, petrochemical facilities, cryogenic equipment, and other process work. Their main strength is good notch toughness at low temperature, which keeps the flange from failing in a brittle way when the system gets very cold.

The flanges come in several types, including weld neck, slip-on, blind, socket weld, lap joint, and threaded, so you can pick the design that fits the pressure, temperature, and connection. They are made in a range of pressure classes and sizes, and they pair with the right gaskets and fittings to form a secure, leak-resistant joint. Along with low-temperature toughness, LF6 offers good tensile strength, weldability, and long service life in demanding conditions. The flanges hold their structural integrity through temperature swings, which is important in lines carrying chilled fluids, gases, or cryogenic media.

Dependable performance is why these flanges get chosen where safety and long-term efficiency come first. Getting the material, machining, and installation right keeps the flange working as intended and holds a tight seal under pressure. Surface finish and face type also affect how well the flange matches the piping system, so the correct choice improves sealing and cuts maintenance. A350 LF6 flanges give a reliable, low-temperature-capable connection with good toughness and resistance to failure in hard service. As a manufacturer, supplier, and stockist, PM Industries ships standard and custom A350 LF6 flanges against fast quotes.

Specification A350 LF6 Flanges

Standards	ANSI/ASME B16.5, B16.48, ANSI Flanges, GOST Flanges, DIN Flanges, EN-1092, B16.47 Series A & B, ASME Flanges, EN Flanges, AWWA Flanges, BS Flanges.
JIS Standard	5K, 10 K, 16 K 20 K, 30 K, 40 K, 63 K
DIN FLANGES	DIN 2527, 2627, 2631, 2656, 2576, 2673, 2629, 2628, 2566, 2641, 2637, 2655, 2634, 2636, 2632, 2633, 2638, 2642, 2573, 2635.
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
Production technique	Forged, machined and Heat treated
Available Flange Type	Weld Neck Flanges, RTJ Flanges, Slip On Flanges, Spectacle Blind Flanges, Flanges Gaskets, Square Flanges, Standard Insert Flanges, High Hub Blinds Flanges, Flat Flanges, forged flanges, Weldo / Nipo Flanges, Jacket Insert Flanges, Tongue groove Flanges, Blind Flanges, Socket Weld Flanges, Large diameter Flanges, Long Weld Neck Flanges, Spacer Blinds, SWRF Flanges, SORF Flanges, Angle Face Rings Flanges, Spades Ring Spacers Flanges, WNRF Flanges, Screwed Flanges, Insert Flanges, flanges bolts, cf flange, Lap Joint Flanges, ASME B16.36 Orifice Flanges, Plate Flange, Expander Flanges, Ring Type Joint Flanges, Loose Flanges, Reducing Flanges, puddle flange, Threaded Flanges, blank flange, vacuum flange.
Connect Type/ Flange Face Type	Ring Type Joint (RTJ), Flat Face (FF), Tongue & Groove, Small Male-Female (SMF), Lap-Joint Face (LJF), Raised Face (RF), Large Male-Female (LMF), Small Tongue.
Custom design	As per your drawing
Test	Direct-reading Spectrograph, X-ray detector, UItrasonic flaw detector, Magnetic particle detector, Hydrostatic testing machine.
Origin	Indian / USA / Korean / West Europe / Japan
Pressure Class	PN 6 TO PN 100
Thickness	Normal Pipe Size ≤ 18
Bore Diameter	Normal Pipe ≤ 10
High Temperature	Above 200°C (400°F) For Class 150 Or Above 400°C (750°F)
Low Temperature	Above -29 Degree C (−20°F)
Coating/Surface Treatment:	Zinc Plated, Anti-rust Paint, Oil Black Paint, Yellow Transparent, Cold and Hot Dip Galvanized.
European/African/Russian Standard Flanges	Available
Gaskets Types	Full Face, Metallic Ring, Flat Ring Gasket
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

Flange Type Available

Chemical Properties

Element	Composition
Carbon, maximum	0.20 maximum
Manganese	0.90 maximum
Phosphorus, maximum	0.035 maximum
Sulfur, maximum	0.040 maximum
Silicon [Note A]	0.20–0.35
Nickel	3.3–3.7
Chromium	0.30 maximum [Note C]
Molybdenum	0.12 maximum [Note C]
Copper	0.40 maximum
Columbium	0.02 maximum
Vanadium	0.03 maximum

Mechanical Properties

Grade/Class	Tensile Strength		Yield Strength, minimum		Elongation, minimum	Hardness, maximum
	ksi	MPa	ksi	MPa	%	HBW
LTCS LF6 CL1	66–91	455–630	52	360	22	197
LTCS LF6 CL2	75–100	515–690	60	415	20	197
LTCS LF6 CL3	75–100	515–690	60	415	20	197

ASME/ANSI B16.5 A350 Lf6 Flanges Dimensions Class-150

Nominal Pipe Size NPS (inches)	Class 150
	Diameter of Flange (inches)	No. of Bolts	Diameter of Bolts (inches)	Diameter of Bolt Holes (inches)	Bolt Circle (inches)
1/4	3-3/8	4	1/2	0.62	2-1/4
1/2	3-1/2	4	1/2	0.62	2-3/8
3/4	3-7/8	4	1/2	0.62	2-3/4
1	4-1/4	4	1/2	0.62	3-1/8
1-1/4	4-5/8	4	1/2	0.62	3-1/2
1-1/2	5	4	1/2	0.62	3-7/8
2	6	4	5/8	0.75	4-3/4
2-1/2	7	4	5/8	0.75	5-1/2
3	7-1/2	4	5/8	0.75	6
3-1/2	8-1/2	8	5/8	0.75	7
4	9	8	5/8	0.75	7-1/2
5	10	8	3/4	0.88	8-1/2
6	11	8	3/4	0.88	9-1/2
8	13-1/2	8	3/4	0.88	11-3/4
10	16	12	7/8	1	14-1/4
12	19	12	7/8	1	17
14	21	12	1	1.12	18-3/4
16	23-1/2	16	1	1.12	21-1/4
18	25	16	1-1/8	1.25	22-3/4
20	27-1/2	20	1-1/8	1.25	25
24	32	20	1-1/4	1.38	29-1/2

A350 Lf6 Material Dimensions Chart According to ASME B16.5

NPS	O.D. of Flange	Flanges Thickness	Diameter of RF	Diameter of Hub at Base	Length Thru Hub			Bore or Diameter		Dia. of Hub at Bevel	Radius of Fillet	Deptd of Socket
					Welding (WN) Neck	Slip-On (SORF) Threaded (NPT) Socket (SWRF)	Lap Joint (Loose)	Slip-on (SORF) Socket (SWRF)	Lap Joint (Loose)
	O	Q	R	X	Y	Y	Y	W	B	H	r	Z
1/2	3-1/2	7/16	1-3/8	1-3/16	1-7/8	5/8	5/8	.88	.90	.84	1/8	3/8
3/4	3-7/8	1/2	1-11/16	1-1/2	2-1/16	5/8	5/8	1.09	1.11	1.05	1/8	7/16
1	4-1/4	9/16	2	1-15/16	2-3/16	11/16	11/16	1.36	1.38	1.32	1/8	1/2
1-1/4	4-5/8	5/8	2-1/2	2-5/16	2-1/4	13/16	13/16	1.70	1.72	1.66	3/16	9/16
1-1/2	5	11/16	2-7/8	2-9/16	2-7/16	7/8	7/8	1.95	1.97	1.90	1/4	5/8
2	6	3/4	3-5/8	3-1/16	2-1/2	1	1	2.44	2.46	2.38	5/16	11/16
2-1/2	7	7/8	4-1/8	3-9/16	2-3/4	1-1/8	1-1/8	2.94	2.97	2.88	5/16	3/4
3	7-1/2	15/16	5	4-1/4	2-3/4	1-3/16	1-3/16	3.57	3.60	3.50	3/8	13/16
3-1/2	8-1/2	15/16	5-1/2	4-13/16	2-13/16	1-1/4	1-1/4	4.07	4.10	4.00	3/8	7/8
4	9	15/16	6-3/16	5-5/16	3	1-5/16	1-5/16	4.57	4.60	4.50	7/16	15/16
5	10	15/16	7.5/16	6-7/16	3-1/2	1-7/16	1-7/16	5.66	5.69	5.56	7/16	15/16
6	11	1	8-1/2	7-9/16	3-1/2	1-9/16	1-9/16	6.72	6.75	6.63	1/2	1-1/16
8	13-1/2	1-1/8	10-5/8	9-11/16	4	1-3/4	1-3/4	8.72	8.75	8.63	1/2	1-1/4
10	16	1-3/16	12-3/4	12	4	1-15/16	1-15/16	10.88	10.92	10.75	1/2	1-5/16
12	19	1-1/4	15	14-3/8	4-1/2	2-3/16	2-3/16	12.88	12.92	12.75	1/2	1-9/16
14	21	1-3/8	16-1/4	15-3/4	5	2-1/4	3-1/8	14.14	14.18	14.00	1/2	1-5/8
16	23-1/2	1-7/16	18-1/2	18	5	2-1/2	3-7/16	16.16	16.19	16.00	1/2	1-3/4
18	25	1-9/16	21	19-7/8	5-1/2	2-11/16	3-13/16	18.18	18.20	18.00	1/2	1-15/16
20	27-1/2	1-11/16	23	22	5-11/16	2-7/8	4-1/16	20.20	20.25	20.00	1/2	2-1/8
24	32	1-7/8	27-1/4	26-1/8	6	3-1/4	4-3/8	24.25	24.25	24.00	1/2	2-1/2

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Pressure Class/ Rating

ASME/ANSI B 16.5	Lap Joint Flange, Ring Type Joint Flange, Threaded Flange, Blind Flange, High Hub Blind Flange, Socket Weld Flange, Slip on Flange, Welding Neck Flange.
PRESSURE CLASS	150, 300, 400, 600, 900, 1500, 2500
ASME/ANSI B 16.47	Blind Flange [Series A & B], Welding Neck Flange.
PRESSURE CLASS	75, 150, 300, 400, 600, 900
ASME/ANSI B 16.36	Slip on Flange, Threaded Flange, Welding Neck Flange.
PRESSURE CLASS	300, 400, 600, 900, 1500, 2500
BS 4504 SEC 3.1	Plate Flange, Welding Neck Flange, Hubbed Slip on Flange, Lapped Pipe End Flange, Loose Plate With Weld Neck Flange, Hubbed Threaded Flange, Blank Flange, Loose Plate Flange.
PRESSURE CLASS	PN 2.5 TO PN 40
BS 4504[PART 1]	Blank Flange, Loose Plate With Weld On Plate Collar, Welding Neck Flange, Plate Flange, Hubbed Slip-On Hubbed Threaded.
PRESSURE CLASS	PN 2.5 TO PN 400
BS 1560 BOSS	Blind Flange, Screwed Boss Flange, Welding Neck Flange,Slip-On Flange, Lapped Flange, Socket Welding Flange.
PRESSURE CLASS	150, 300, 400, 600, 900, 1500, 2500
BS10	Screwed Boss Flange, Plate Slip-On Flange, Slip-On Boss Flange, Blind Flange, Welding Neck Flange.
TABLE	D, E, F, H
DIN FLANGES	DIN 2527, 2632, 2635, 2673, 2566, 2655, 2631, 2627, 2634, 2576, 2636, 2629, 2633, 2573, 2656, 2638, 2637, 2642, 2641, 2628
PRESSURE CLASS	PN 6 TO PN 100

ASTM A350 LF6 Class 2 Thickness Chart In MM

ASTM A350 LF6 Flanges Wall Thickness
NPS (Normal Pipe Sizes)	Outside Daimeter (O.D.)	Schedule 10	Schedule 20	Schedule 30	STD Wall	Schedule 40	Schedule 60	EXT Hvy	Schedule 80	Schedule 100	Schedule 120	Schedule 140	Schedule 160	XX Hvy
½	0.84	0.083	...	...	0.109	0.109	...	0.147	0.147	...	...	...	0.188	0.294
¾	1.05	0.083	...	...	0.113	0.113	...	0.154	0.154	...	...	...	0.219	0.308
1	1.315	0.109	...	...	0.133	0.133	...	0.179	0.179	...	...	...	0.25	0.358
1 ¼	1.66	0.109	...	...	0.14	0.14	...	0.191	0.191	...	...	...	0.25	0.382
1 ½	1.9	0.109	...	...	0.145	0.145	...	0.2	0.2	...	...	...	0.281	0.4
2	2.375	0.109	...	...	0.154	0.154	...	0.218	0.218	...	...	...	0.344	0.436
2 ½	2.875	0.12	...	...	0.203	0.203	...	0.276	0.276	...	...	...	0.375	0.552
3	3.5	0.12	...	...	0.216	0.216	...	0.3	0.3	...	...	...	0.438	0.6
3 ½	4	0.12	...	...	0.226	0.226	...	0.318	0.318	...	...	...	...	0.636
4	4.5	0.12	...	...	0.237	0.237	...	0.337	0.337	...	0.438	...	0.531	0.674
5	5.563	0.134	...	...	0.258	0.258	...	0.375	0.375	...	0.5	...	0.625	0.75
6	6.625	0.134	...	...	0.28	0.28	...	0.432	0.432	...	0.562	...	0.719	0.864
8	8.625	0.148	0.25	0.277	0.322	0.322	0.406	0.5	0.5	0.594	0.719	0.812	0.906	0.875
10	10.75	0.165	0.25	0.307	0.365	0.365	0.5	0.5	0.594	0.719	0.844	1	1.125	1
12	12.75	0.18	0.25	0.33	0.375	0.406	0.562	0.5	0.688	0.844	1	1.125	1.312	1
14	14	0.25	0.312	0.375	0.375	0.438	0.594	0.5	0.75	0.938	1.094	1.25	1.406	...
16	16	0.25	0.312	0.375	0.375	0.5	0.656	0.5	0.844	1.031	1.219	1.438	1.594	...
18	18	0.25	0.312	0.438	0.375	0.562	0.75	0.5	0.938	1.156	1.375	1.562	1.781	...
20	20	0.25	0.375	0.5	0.375	0.594	0.812	0.5	1.031	1.281	1.5	1.75	1.969	...
22	22	0.25	...	...	0.375	...	...	0.5	...	...	....	....	....	....
24	24	0.25	0.375	0.562	0.375	0.688	0.969	0.5	1.219	1.531	1.812	2.062	2.344	....
26	26	....	....	....	0.375	....	....	0.5	....	....	....	....	....	....
30	30	0.312	0.5	0.625	0.375	....	....	0.5	....	....	....	....	....	....
36	36	0.312	0.5	0.625	0.375	0.75	....	0.5	....	....	....	....	....	....
40	40	....	....	....	0.375	....	....	0.5	....	....	....	....	....	....
42	42	……..	……..	……..	0.375	……..	……..	0.5	……..	……..	……..	……..	……..	……..
48	48	……..	……..	……..	0.375	……..	……..	0.5	……..	……..	……..	……..	……..	……..

SA350 LF6 Weight Chart

Nominal Pipe Sizes (NPS)	Slip On (SORF)	Threaded (NPT)	Socket Weld (SWRF)	Lap Joint (Loose)	Blind (BLRF)	Weld Neck (WRNR)
½	1	1	2	1	2	2
¾	2	2	2	2	2	2
1	2	2	2	2	2	3
1¼	3	3	3	3	3	3
1½	3	3	3	3	4	4
2	5	5	5	5	5	6
2½	8	8	8	8	7	10
3	9	9	9	9	9	11.5
3½	11	12	11	11	13	12
4	13	13	13	13	17	16.5
5	15	15	15	15	20	21
6	19	19	19	19	27	26
8	30	30	30	30	47	42
10	43	43	43	43	70	54
12	64	64	64	64	123	88
14	90	90	90	105	140	114
16	106	98	98	140	180	140
18	130	130	130	160	220	165
20	165	165	165	195	285	197
22	185	185	185	245	355	225
24	220	220	220	275	430	268