Alloy Steel Flanges

Alloy Steel Flanges

ASTM A182 chrome-moly forged flanges in F5, F9, F11, F22 and F91 – weld neck, slip-on, blind, socket weld and RTJ flanges for high-temperature, high-pressure piping.

ASTM A182 / ASME SA182 1/2" – 48" NB Class 150 – 2500

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Alloy Steel Flanges

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Forged Chrome-Moly Flanges

ASTM A182 Alloy Steel Flanges

Tubewell Steel & Engg. Co. is a manufacturer, stockist and supplier of ASTM A182 alloy steel flanges from Mumbai, India. Our range covers F5, F9, F11, F12, F22 and F91 chrome-molybdenum grades in every common pattern – weld neck, slip-on, blind, socket weld, threaded, lap joint and RTJ – machined to ASME B16.5, B16.47 and EN 1092-1 for power, refinery and petrochemical piping.

StandardASTM A182 / ASME SA182

GradesF5, F9, F11, F22, F91

Size Range1/2" NB – 48" NB

Pressure Class150 – 2500 / PN6 – PN64

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Product Overview

Forged chrome-moly flanges for elevated-temperature piping systems

Alloy steel flanges are forged from ferritic chromium-molybdenum steels covered by ASTM A182 / ASME SA182. Chromium (1% to 10%) gives resistance to oxidation, sulphidation and high-temperature hydrogen attack, while molybdenum (0.5% to 1%) raises creep and stress-rupture strength. This makes chrome-moly flanges the natural mating component for A335 P-grade pipes and A234 WP-grade fittings in steam, hydrocarbon and hydrogen service where carbon steel flanges would lose strength.

Every flange we supply starts as a certified forging that is heat treated – annealed or normalized and tempered as A182 requires – and then CNC machined to ASME B16.5, ASME B16.47 Series A / B, MSS SP-44 or EN 1092-1. Bores are matched to the connecting pipe schedule, faces are serrated to 125–250 µin Ra for spiral-wound gaskets, and each piece is hard-stamped with grade, size, class and heat number for full traceability. EN 10204 3.1 / 3.2 certificates, IBR documentation and third-party inspection are available on request.

Grades F5, F5a, F9, F11, F12, F22 & F91
Class 150 to 2500 and PN6 to PN64
RF, FF and RTJ facings, bore to any schedule
Heat treated forgings with full traceability
IBR, NACE MR0175 & TPI supply on request
Ready stock in Mumbai for fast dispatch

ASTM A182 F5 Flanges

5Cr-0.5Mo flanges for refinery heaters and hot hydrogen lines.

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ASTM A182 F9 Flanges

9Cr-1Mo flanges for sour, high-sulphur crude service.

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F11

ASTM A182 F11 Flanges

1.25Cr-0.5Mo flanges in Class 1, 2 and 3 for steam lines.

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F22

ASTM A182 F22 Flanges

2.25Cr-1Mo flanges with higher creep strength for boilers.

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F91

ASTM A182 F91 Flanges

9Cr-1Mo-V flanges for supercritical power plant piping.

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WNRF

Weld Neck Flanges

Tapered-hub flanges for high-pressure, cyclic-load service.

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SORF

Slip On Flanges

Easy-to-align flanges for low and moderate pressure lines.

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BLRF

Blind Flanges

Solid flanges to close pipe ends, vessels and test points.

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Specifications

Standard supply range for ASTM A182 alloy steel flanges

Parameter	Details
Material Standard	ASTM A182, ASME SA182
Grades	F5, F5a, F9, F11 Class 1 / 2 / 3, F12 Class 1 / 2, F22 Class 1 / 3, F91
Dimension Standard	ASME B16.5 (1/2" – 24"), ASME B16.47 Series A & B (26" – 48"), MSS SP-44, EN 1092-1
Size	1/2" NB to 48" NB (DN 15 – DN 1200)
Pressure Class	ASME Class 150, 300, 600, 900, 1500, 2500
PN Rating	PN6, PN10, PN16, PN25, PN40, PN64
Flange Types	Weld Neck, Slip-On, Blind, Socket Weld, Threaded, Lap Joint, Ring Type Joint, Long Weld Neck, Reducing, Orifice, Spectacle Blind, Spacer & Paddle
Facing	Raised Face (RF), Flat Face (FF), Ring Type Joint (RTJ), Tongue & Groove, Male & Female
Face Finish	Serrated 125 – 250 µin Ra (3.2 – 6.3 µm), smooth finish on request
Bore / Schedule	SCH 10, 20, 40, STD, 60, 80, XS, 100, 120, 140, 160, XXS
Manufacturing	Closed / open die forged or seamless rolled ring, CNC machined
Heat Treatment	Annealed or Normalized & Tempered as per ASTM A182 (F91: Normalized & Tempered)
Testing	PMI, Hardness, Tensile, Impact, UT, MPI / DPT, Macro, Visual & Dimensional
Certificates	EN 10204 3.1 / 3.2, IBR Certification, NACE MR0175, TPI Reports

Material Grades & Equivalents

International equivalents of ASTM A182 chrome-moly flange grades

Grade	ASTM / ASME	UNS	EN 10222-2	W.Nr.	JIS G3203	Nominal
F5	A182 F5	K41545	X16CrMo5-1	1.7366	SFVAF5B	5Cr-0.5Mo
F9	A182 F9	K90941	X11CrMo9-1	1.7386	SFVAF9	9Cr-1Mo
F11	A182 F11 Cl.2	K11572	13CrMo4-5	1.7335	SFVAF11A	1.25Cr-0.5Mo
F12	A182 F12	K11562	13CrMo4-5	1.7335	SFVAF12	1Cr-0.5Mo
F22	A182 F22 Cl.3	K21590	11CrMo9-10	1.7383	SFVAF22B	2.25Cr-1Mo
F91	A182 F91	K90901	X10CrMoVNb9-1	1.4903	SFVAF28	9Cr-1Mo-V

Equivalents are the nearest comparable grades for reference; confirm suitability against the governing design code before substitution.

Chemical Composition

Weight %, as per ASTM A182

CCarbon0.05–0.25

MnManganese0.30–0.60

SiSilicon≤ 1.00

CrChromium0.80–10.0

MoMolybdenum0.44–1.13

VVanadium (F91)0.18–0.25

NbNiobium (F91)0.06–0.10

Grade	C	Mn	P max	S max	Si	Cr	Mo	Others
F5	0.15 max	0.30 – 0.60	0.030	0.030	0.50 max	4.0 – 6.0	0.44 – 0.65	Ni 0.50 max
F5a	0.25 max	0.60 max	0.040	0.030	0.50 max	4.0 – 6.0	0.44 – 0.65	Ni 0.50 max
F9	0.15 max	0.30 – 0.60	0.030	0.030	0.50 – 1.00	8.0 – 10.0	0.90 – 1.10	–
F11 Cl.1	0.05 – 0.15	0.30 – 0.60	0.030	0.030	0.50 – 1.00	1.00 – 1.50	0.44 – 0.65	–
F11 Cl.2 / 3	0.10 – 0.20	0.30 – 0.80	0.040	0.040	0.50 – 1.00	1.00 – 1.50	0.44 – 0.65	–
F12 Cl.1	0.05 – 0.15	0.30 – 0.60	0.045	0.045	0.50 max	0.80 – 1.25	0.44 – 0.65	–
F22 Cl.1 / 3	0.05 – 0.15	0.30 – 0.60	0.040	0.040	0.50 max	2.00 – 2.50	0.87 – 1.13	–
F91	0.08 – 0.12	0.30 – 0.60	0.020	0.010	0.20 – 0.50	8.0 – 9.5	0.85 – 1.05	V 0.18–0.25, Nb 0.06–0.10, N 0.03–0.07, Ni 0.40 max, Al 0.02 max

Mechanical Properties

Minimum values at room temperature, as per ASTM A182

Grade	Tensile Strength	Yield Strength (0.2%)	Elongation (in 2")	Reduction of Area	Hardness (HBW)
F5	485 MPa (70 ksi) min	275 MPa (40 ksi) min	20% min	35% min	143 – 217
F5a	620 MPa (90 ksi) min	450 MPa (65 ksi) min	22% min	50% min	187 – 248
F9	585 MPa (85 ksi) min	380 MPa (55 ksi) min	20% min	40% min	179 – 217
F11 Cl.1	415 MPa (60 ksi) min	205 MPa (30 ksi) min	20% min	45% min	121 – 174
F11 Cl.2	485 MPa (70 ksi) min	275 MPa (40 ksi) min	20% min	30% min	143 – 207
F11 Cl.3	515 MPa (75 ksi) min	310 MPa (45 ksi) min	20% min	30% min	156 – 207
F12 Cl.2	485 MPa (70 ksi) min	275 MPa (40 ksi) min	20% min	30% min	143 – 207
F22 Cl.1	415 MPa (60 ksi) min	205 MPa (30 ksi) min	20% min	35% min	170 max
F22 Cl.3	515 MPa (75 ksi) min	310 MPa (45 ksi) min	20% min	30% min	156 – 207
F91	620 MPa (90 ksi) min	415 MPa (60 ksi) min	20% min	40% min	248 max

620MPa

Highest Min. Tensile (F91)

415MPa

Highest Min. Yield (F91)

20%

Min. Elongation (All Grades)

Physical Properties

Typical values (for reference)

Property	F5	F9	F11	F22	F91
Density (g/cm³)	7.75	7.70	7.75	7.80	7.76
Modulus of Elasticity (GPa)	210	213	205	210	218
Thermal Conductivity at 100°C (W/m·K)	33	26	37	36	26
Mean Thermal Expansion 20–300°C (µm/m·°C)	11.9	11.6	12.4	12.6	11.3
Specific Heat (J/g·°C)	0.46	0.46	0.46	0.46	0.45
Melting Range (°C)	1450 – 1510	1420 – 1500	1450 – 1510	1450 – 1510	1420 – 1500
Approx. Max. Service Temp. (°C)	≈ 650	≈ 650	≈ 595	≈ 600	≈ 650

Dimension Chart

ASME B16.5 Class 150 & Class 300 flanges – dimensions in mm

Showing popular sizes. Class 600 – 2500 and B16.47 sizes on request.

NPS	Cl.150 OD	Cl.150 Thk	Cl.150 BCD	Cl.150 Bolts	Cl.300 OD	Cl.300 Thk	Cl.300 BCD	Cl.300 Bolts	RF Dia
1/2"	90	9.6	60.3	4 × 1/2"	95	12.7	66.7	4 × 1/2"	34.9
3/4"	100	11.2	69.9	4 × 1/2"	115	14.3	82.6	4 × 5/8"	42.9
1"	110	12.7	79.4	4 × 1/2"	125	15.9	88.9	4 × 5/8"	50.8
1 1/4"	115	14.3	88.9	4 × 1/2"	135	17.5	98.4	4 × 5/8"	63.5
1 1/2"	125	15.9	98.4	4 × 1/2"	155	19.1	114.3	4 × 3/4"	73.0
2"	150	17.5	120.7	4 × 5/8"	165	20.7	127.0	8 × 5/8"	92.1
2 1/2"	180	20.7	139.7	4 × 5/8"	190	23.9	149.2	8 × 3/4"	104.8
3"	190	22.3	152.4	4 × 5/8"	210	27.0	168.3	8 × 3/4"	127.0
4"	230	22.3	190.5	8 × 5/8"	255	30.2	200.0	8 × 3/4"	157.2
5"	255	22.3	215.9	8 × 3/4"	280	33.4	235.0	8 × 3/4"	185.7
6"	280	23.9	241.3	8 × 3/4"	320	35.0	269.9	12 × 3/4"	215.9
8"	345	27.0	298.5	8 × 3/4"	380	39.7	330.2	12 × 7/8"	269.9
10"	405	28.6	362.0	12 × 7/8"	445	46.1	387.4	16 × 1"	323.8
12"	485	30.2	431.8	12 × 7/8"	520	49.3	450.8	16 × 1 1/8"	381.0
14"	535	33.4	476.3	12 × 1"	585	52.4	514.4	20 × 1 1/8"	412.8
16"	595	35.0	539.8	16 × 1"	650	55.6	571.5	20 × 1 1/4"	469.9
18"	635	38.1	577.9	16 × 1 1/8"	710	58.8	628.6	24 × 1 1/4"	533.4
20"	700	41.3	635.0	20 × 1 1/8"	775	62.0	685.8	24 × 1 1/4"	584.2
24"	815	46.1	749.3	20 × 1 1/4"	915	68.3	812.8	24 × 1 1/2"	692.2

OD = Flange Outside Diameter, Thk = Minimum Flange Thickness (excluding 2 mm / 0.06" raised face), BCD = Bolt Circle Diameter, Bolts = No. × Bolt Diameter. All dimensions in mm unless noted.

Applications

Where ASTM A182 alloy steel flanges are used

Power Plants

Main steam, hot reheat and feed-water lines in thermal and supercritical units.

Refineries

Crude, vacuum and hydrocracker units handling hot, sulphur-bearing streams.

Petrochemicals

Reformers, crackers and hydrogen piping at elevated temperature and pressure.

Boilers & HRSG

Header, superheater and reheater connections exposed to sustained heat.

Oil & Gas

Process skids, manifolds and pressure vessels in upstream and midstream plants.

Fertilizer Plants

Ammonia and urea synthesis loops that need hydrogen-attack resistance.

Testing & Why Choose Us

Quality you can verify on every heat

Ready Stock

Large inventory for fast dispatch

Certified Material

MTC EN 10204 3.1 / 3.2

100% PMI

Positive material identification

On-time Delivery

Pan-India & export shipping

Visual & Dimensional PMI Test Hardness Test Tensile Test Impact Test Ultrasonic Test MPI / DP Test Macro / Micro Test

Frequently Asked Questions

Quick answers about alloy steel flanges

We supply ASTM A182 / ASME SA182 F5, F5a, F9, F11 (Class 1, 2 and 3), F12, F22 (Class 1 and 3) and F91 flanges. F11 Class 2, F22 Class 3 and F91 are the most commonly stocked grades for power and refinery projects.

The choice follows the connecting pipe and design temperature. F11 (1.25Cr-0.5Mo) suits moderate temperatures, F22 (2.25Cr-1Mo) offers higher creep strength for boiler and steam service, and F91 (9Cr-1Mo-V) is used in supercritical plants where its much higher allowable stress allows thinner, lighter components.

Flanges are made to ASME B16.5 (1/2" to 24") in Class 150 to 2500, ASME B16.47 Series A and B (26" to 48"), MSS SP-44 and EN 1092-1 in PN6 to PN64. Custom drawings and non-standard bores can also be machined.

Each consignment ships with EN 10204 3.1 mill test certificates showing chemistry, mechanical results and heat treatment. EN 10204 3.2, IBR certification and inspection by agencies such as TÜV, BV, SGS or Lloyd's can be arranged on request.

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