ASTM Materials for Forged Flanges (A105-A182)

Author: Matteo Pusterla | 20 min read

Application	Flange Grade	Matching Pipe
High-temp CS	A105	A53, A106, API 5L
Low-temp CS	A350 LF1/2/3	A333
High-yield CS	A694 F42–F80	API 5L X42–X80
Alloy steel	A182 F5–F91	A335 P5–P91
Stainless steel	A182 F304/316	A312
Duplex	A182 F51/F53/F55	A790/A928
Nickel alloy	B564 (Inconel, Monel, Hastelloy)	-

Carbon Steel Flanges

When to Use Carbon Steel

Carbon Steel Flange Materials

Condition	CS Flanges Suitable?
Moderate to high pressure	Yes
Ambient to high temperature	Yes (to 425°C)
Non-corrosive/mildly corrosive	Yes
Highly corrosive (acids, chlorides)	No-use SS or alloy
Cost-sensitive projects	Yes (most economical)

Applications: Oil & gas, petrochemical, water treatment, steam/gas distribution, structural.

Carbon Steel Grades

ASTM A105 (high-temperature carbon steel) to match A53, A106, API 5L carbon steel pipes
ASTM A350 LF1, LF2, LF3 (low-temperature carbon steel) to match ASTM A333 pipes
ASTM A694 F42, F52, F60, F65 (high-yield carbon steel to match API 5L X42, X52, X60, and X65 steel pipes

Chemical Composition ASTM A105, A350, A694

ASTM A105 (High-temperature carbon steel flange material)

Grade	C	Mn	P	S	Si	Cu	Ni	Cr	Mo	V
A105	0.35	0.60-1.05	0.035	0.040	0.10-0.35	0.40	0.40	0.30	0.12	0.08

ASTM A350 (Low-Temperature carbon steel flange material)

	C%	Mn%	Si%	S%	P%	Cr%	Ni%
A350 LF1	0.30 max	0.6/1.35	.15/.30	.040 max	.035 max	0.30 max	0.40 max
A350 LF2	0.30 max	0.6/1.35	.15/.30	.040 max	.035 max	0.30 max	0.40 max
A350 LF3	0.20 max	0.9	.20/.35	.040 max	.035 max	0.30 max	3.3/3.7

ASTM A694 (High-yield carbon steel flanges)

	C	Mn	P	S	Si
ASTM A694 F42	0.26-0.265	1.60-1.64	0.025-0.030	0.025-0.030	0.15-0.35
ASTM A694 F52	0.26-0.265	1.60-1.64	0.025-0.030	0.025-0.030	0.15-0.35
ASTM A694 F60	0.26-0.265	1.60-1.64	0.025-0.030	0.025-0.030	0.15-0.35
ASTM A694 F65	0.26-0.265	1.60-1.64	0.025-0.030	0.025-0.030	0.15-0.35

Mechanical Properties A105, A350, A694

ASTM A105 (High-temperature carbon steel flange material)

Property	ASTM A105	ASTM A350-LF2
Tensile Strength Min, psi	70,000	70,000-95,000
Tensile Strength Min, N/mm²	485	485-655
Yield Strength Min, psi	36,000	36,000
Yield Strength Min, N/mm²	250	250
Elongation (%)	22	22
Reduction of Area (%)	30	30
Hardness, maximum	187	–
CVN at -50℉	–	15/12 ft-lbs (20/16 joules)

ASTM A694 (High-yield carbon steel flanges)

Grade	Min Yield Strength ksi [MPa]	Min Tensile Strength ksi [MPa]	Elongation min %
A694 F42	42 [290]	60 [415]	20
A694 F46	46 [315]	60 [415]	20
A694 F48	48 [330]	62 [425]	20
A694 F50	50 [345]	64 [440]	20
A694 F52	52 [360]	66 [455]	20
A694 F56	56 [385]	68 [470]	20
A694 F60	60 [415]	75 [515]	20
A694 F65	65 [450]	77 [530]	20
A694 F70	70 [485]	82 [565]	18

Alloy Steel Flanges

When to Use Alloy Steel (Chrome-Moly)

Alloy Steel Flange Materials

Chrome-moly flanges (A182 F1, F5, F9, F11, F22, F91) match A335 alloy pipes. They offer high-temperature strength, oxidation resistance, and better corrosion resistance than carbon steel.

Application	Why Alloy Steel
High temperature (to 650°C)	Cr/Mo improves creep resistance
High pressure	Enhanced mechanical strength
Refineries/chemical plants	Resists thermal stress
Power generation	Boilers, turbines, heat exchangers
Mildly corrosive	Better oxidation resistance than CS

Chemical Composition ASTM A182 F5, F9, F11, F22

Element	F11 CL2	F22 CL3	F5	F9
Carbon	0.10-0.20	0.05-0.15	0.15 max	0.15 max
Manganese	0.30-0.80	0.30-0.60	0.30-0.60	0.30-0.60
Phosphorus max	0.040	0.040	0.03	0.030
Sulfur max	0.040	0.040	0.03	0.030
Silicon	0.50-1.00	0.50 max	0.50 max	0.50-1.00
Nickel max	–	–	0.50	–
Chromium	1.00-1.50	2.00-2.50	4.00-6.00	8.0-10.0
Molybdenum	0.44-0.65	0.87-1.13	0.44-0.65	0.90-1.10
Copper max	–	–	–	–
Columbium max	–	–	–	–
Vanadium max	–	–	–	–

Mechanical Properties A182

Property	F11 CL2	F22 CL3	F5	F9
Tensile Strength psi (MPa)	70,000 (485)	75,000 (515)	70,000 (485)	85,000 (585)
Yield Strength psi min	40,000 (275)	45,000 (310)	40,000 (275)	55,000 (380)
Elongation 2” % min	20	20	20	20
Reduction Area % min	30	30	35	40
Hardness (HB) max	143-207	156-207	143-217	179-217

Recommended service for alloy steel flange material grades ASTM A182:

ASTM A182 ALLOY STEEL FLANGE	TRADE DESIGNATION	RECOMMENDED SERVICE
A182 F1	C-1/2 Mo Low Alloy Steel	Non-corrosive applications Including water, oil, and gases at temperatures between -29 ~ 593ºC* (Not prolonged use > 470ºC).
A182 F2	0.75% Ni; Mo; 0.75% Cr Low Alloy Steel	Non-corrosive applications including water, oil, and gases at temperatures F2:-29ºC ~ 538ºC, WC5: -29ºC ~ 575ºC
A182 F11	1 1/4% Chrome; 1/2% Moly Low Alloy Steel	Non-corrosive applications inclusive of water, oil, and gases at temperatures between -30ºC (-20ºF) and +593ºC (+1100ºF).
A182 F22	2 1/4% Chrome Low Alloy Steel	Non-corrosive applications inclusive of water, oil, and gases at temperatures between -30ºC (-20ºF) and +593ºC (+1100ºF).
A182 F5/F5a	5% Chrome; 1/2% Moly, Medium Alloy Steel	Mild corrosive or erosive applications as well as non-corrosive applications at temperatures between -30ºC (-20ºF) and +650ºC (+1200ºF).
A182 F9	9% Chrome; 1% Moly, Medium Alloy Steel	Mild corrosive or erosive applications as well as non-corrosive applications at temperatures between -30ºC (-20ºF) and +650ºC (+1200ºF).
A182 F91	9% Chrome; 1% Moly; V-N, Medium Alloy Steel	Mild corrosive or erosive applications as well as non-corrosive applications at temperatures between -30ºC (-20ºF) and +650ºC (+1200ºF).

Stainless Steel Flanges

When to Use Stainless Steel

Stainless Steel Flange Materials ASTM A182

Stainless steel flanges (A182 F304/316/321) match A312 SS pipes. High chromium content provides excellent corrosion resistance.

Application	Why Stainless Steel
Corrosive environments	Resists acids, alkalis, salts
Food & beverage	Non-reactive, easy to clean/sterilize
Pharmaceutical/biotech	Maintains purity, no contamination
High temperature	316/310/321 resist scaling
Cryogenic (LNG)	Austenitic grades retain toughness
Marine/coastal	Saltwater corrosion resistance

Grade selection:

304/304L: General purpose, good corrosion resistance
316/316L: Better resistance (Mo content), chloride environments
321: Stabilized for high-temperature service

Cost factors: SS prices depend on Ni, Cr, Mo content fluctuating on the LME.

Chemical Composition ASTM A182 F304/F316/F321

ASTM A182 Stainless Steel Flanges Materials Composition, %

Grade	C	Mn	P	S	Si	Ni	Cr	Mo	Nb	Ti	Others
F304(1)	0.08	2.0	0.045	0.030	1.0	8.0-11.0	18.0-20.0
F304H	0.04-0.10	2.0	0.045	0.030	1.0	8.0-11.0	18.0-20.0
F304L(1)	0.030	2.0	0.045	0.030	1.0	8.0-13.0	18.0-20.0
F304N(2)	0.08	2.0	0.045	0.030	1.0	8.0-10.5	18.0-20.0
F304LN(2)	0.030	2.0	0.045	0.030	1.0	8.0-10.5	18.0-20.0
F309H	0.04-0.10	2.0	0.045	0.030	1.0	12.0-15.0	22.0-24.0
F310	0.25	2.0	0.045	0.030	1.0	19.0-22.0	24.0-26.0
F310H	0.04-0.10	2.0	0.045	0.030	1.0	19.0-22.0	24.0-26.0
F310MoLN	0.030	2.0	0.030	0.015	0.40	21.0-23.0	24.0-26.0	2.0-3.0			N 0.10-0.16
F316	0.08	2.0	0.045	0.030	1.0	10.0-14.0	16.0-18.0	2.0-3.0
F316H	0.04-0.10	2.0	0.045	0.030	1.0	10.0-14.0	16.0-18.0	2.0-3.0
F316L(1)	0.030	2.0	0.045	0.030	1.0	10.0-15.0	16.0-18.0	2.0-3.0
F316N(2)	0.08	2.0	0.045	0.030	1.0	11.0-14.0	16.0-18.0	2.0-3.0
F316LN(2)	0.030	2.0	0.045	0.030	1.0	11.0-14.0	16.0-18.0	2.0-3.0
F316Ti	0.08	2.0	0.045	0.030	1.0	10.0-14.0	16.0-18.0	2.0-3.0		(3)	N 0.10 max
F317	0.08	2.0	0.045	0.030	1.0	11.0-15.0	18.0-20.0	3.0-4.0
F317L	0.030	2.0	0.045	0.030	1.0	11.0-15.0	18.0-20.0	3.0-4.0
F321	0.08	2.0	0.045	0.030	1.0	9.0-12.0	17.0-19.0			(4)
F321H	0.04-0.10	2.0	0.045	0.030	1.0	9.0-12.0	17.0-19.0			(5)
F347	0.08	2.0	0.045	0.030	1.0	9.0-13.0	17.0-20.0		(6)
F347H	0.04-0.10	2.0	0.045	0.030	1.0	9.0-13.0	17.0-20.0		(7)
F348	0.08	2.0	0.045	0.030	1.0	9.0-13.0	17.0-20.0		(6)		Co 0.20 Ta 0.10
F348H	0.04-0.10	2.0	0.045	0.030	1.0	9.0-13.0	17.0-20.0		(7)		Co 0.20 Ta 0.10

Notes:

Grades F304, F304L, F316, and F316L shall have a maximum Nitrogen of 0.10%.
Grades F304N, F316N, F304LN, and F316LN shall have a Nitrogen of 0.10 to 0.16%.
Grade F316Ti shall have a Titanium content five times above the Carbon plus Nitrogen and not more than 0.70%.
Grade F321 shall have a Titanium content five times above the Carbon and not more than 0.70%.
Grade F321H shall have a Titanium content four times above the Carbon and not more than 0.70%.
Grades F347 and F348 shall have a Niobium content ten times above the Carbon and not more than 1.10%.
Grades F347H and F348H shall have a Niobium content above than eight times the Carbon and not more than 1.10%.

Mechanical Properties A182 F304/F316/F321

ASTM A182 Grade	Minimum Tensile Strengthin MPa	Minimum Yield pointin Mpa	Minimum Elongationin %	Minimum Reduction of inmin, %
ASTM A182 F304	515	205	30	50
ASTM A182 F304L	485	170	30	50
ASTM A182 F316	515	205	30	50
ASTM A182 F316L	485	170	30	50
ASTM A182 F321	515	205	30	50

Recommended service for stainless steel flange materials:

MATERIAL	MATERIAL GROUP	RECOMMENDED SERVICE
A182-F304	18% Cr, 8% Ni Stainless Steel	Corrosive services and atmospheres from -450°F to 1000°F (-268°C to 537°C)
A182-F316	18% Cr, 8% Ni, 2% Mo Stainless Steel	High resistance to corrosion from -450°F to 1000°F (-268°C to 537°C).

ASTM vs. EN Stainless Steel Flange Materials

Flanges Material Grades: Comparison of European and American Standards

Material Number	EN	ASTM
1.4541 X 6 CrNiTi 18 10	X6CrNiTi18-10	A 182 Grade F321
1.4571 X 6 CrNiMoTi 17 12 2	X6CrNiMoTi17-12-2	A 182 Grade F316Ti
1.4301 X 5 CrNi 18 10	X5CrNi18-10	A 182 Grade F304
1.4306 X 2 CrNi 19 11	–	A 182 Grade F304L
1.4307	X2CrNi18-9	A 182 Grade F304L
1.4401 X 5 CrNiMo 17 12 2	X5CrNiMo17-12-2	A 182 Grade F316
1.4404 X 2 CrNiMo 17 13 2	X2CrNiMo17-12-2	A 182 Grade F316L
1.4462 X 2 CrNiMoN 22 5 3	X2CrNiMoN22-5-3	A 182 Grade F51 (Duplex)
1.4529 X 1 NiCrMoCuN 25 20 6	X1NiCrMoCuN25-20-7	UNS N 08926
1.4539 X 1 NiCrMoCuN 25 20 5	X1NiCrMoCu25-20-5	A 182 Grade F904L
1.4547	X1CrNiMoCuN20-18-7	UNS S 31254

Duplex Flanges

When to Use Duplex/Super Duplex

Duplex Flange ASTM A182 UNS S31803 UNS S32205

Duplex flanges (A182 F51/F53/F55) match A790/A928 pipes. The austenite + ferrite microstructure provides:

2× strength of austenitic SS (304/316)
Superior corrosion resistance to chlorides/sulfides
Magnetic properties (unlike austenitic SS)

Application	Why Duplex/Super Duplex
Chloride environments	Excellent pitting/crevice corrosion resistance
High-pressure systems	Mechanical strength >> standard SS
Offshore/marine	Seawater and H₂S resistance
Chemical processing	Handles aggressive chemicals
Desalination	Chloride corrosion resistance
Pollution control	Resists acidic flue gases

Grade	UNS	Cr	Mo	Ni	Cu
Duplex 2205	S31803/S32205	21-23%	2.5-3.5%	4.5-6.5%	-
Super Duplex	S32750/S32760	24-26%	3-5%	5.5-8%	0.5-3%

Chemical Composition ASTM A182 Duplex and Super Duplex

%	Duplex 2205(ASTM A182 UNS S31803 – UNS S32205)	Super DuplexASTM A182 UNS S32750 – 32760)
C	0-0.03	0.03 max
Mn	2.0	1.5
Si	1.0	0.8
P	0-0.03	0.035
S	0-0.02	0.02
Cr	21-23	24-26
Mo	2.5-3.5	3.0-5.0
Ni	4.5-6.5	5.5-8.0
N	0.08-0.2	0.2-0.35
Cu	–	0.5-3.0

The most widely used duplex flange grade is 2205, due to its superior corrosion resistance and mechanical strength. The designation “2205” refers to the chemical composition: 22% Chromium and 5% Nickel.

Super Duplex flanges offer even higher strength and corrosion resistance than standard duplex steel. The main difference is the addition of copper to the alloy (along with increased Chromium, Molybdenum, and Nickel). Copper gives Super Duplex improved resistance to hot chlorides and strong reducing acids such as sulphuric acid.

While UNS S31803/S32205 (duplex) and UNS S32750/S32760 (super duplex) are standard designations, most superalloy manufacturers use proprietary trade names (e.g., UR52N+ by Usinor/Arcelor, Ferralium, Zeron, Sandvik SAF 2205 22Cr).

Mechanical Properties A182 Duplex and Super Duplex

Mechanical Properties	Duplex 2205(ASTM A182 UNS S31803 – UNS S32205)	Super DuplexASTM A182 UNS S32750 – 32760)
Tensile Strength (in MPa)	620	770
Proof Stress 0.2% (in MPa)	450	550
A5 Elongation (in %)	25	25

Physical Attribute	Duplex 2205(ASTM A182 UNS S31803 – UNS S32205)	Super DuplexASTM A182 UNS S32750 – 32760)
Density (g.cm3)	7.805	7.810
Modulus of Elasticity (GPa)	200	205
Electrical Resistivity (Ω.m)	0.085×10-6	0.085×10-6
Thermal Conductivity (W/m.K)	19 at 100°C	17 at 100°C
Thermal Expansion (m/m.K)	13.7×10-6 to 100°C	13.5×10-6 to 200°C

Nickel Alloy Flanges

When to Use Nickel Alloys

Nickel alloy flanges (Inconel, Hastelloy, Monel, Alloy 20) are specified when other materials cannot withstand the corrosion, temperature, or pressure demands.

Application	Why Nickel Alloy
Extreme corrosion	Resists acids, alkalis, chlorides
High temperature	Maintains strength at elevated temps
Cryogenic (LNG)	Retains toughness at low temps
Marine/offshore	Seawater corrosion resistance
Nuclear reactors	Withstands radioactive environments
Pollution control	Resists acidic flue gases

ASTM Specifications for Nickel Alloy Flanges

ASTM Specification	Flange Type
ASTM B160	Nickel 200 Flange
ASTM B166	Inconel 600 Flange
ASTM B564	Inconel 625 Flange
ASTM B425	Incoloy 800 Flange
ASTM B564	Incoloy 825 Flange
ASTM B564	Monel K400 Flange
ASTM B564	Hastelloy C276 Flange

Chemical Composition Nickel-Alloy Flanges

Superalloy Grade	UNS	C	Mn	S	Si	Cr	Ni	Mo	Cu	Ti	Fe
Nickel 200	N02200	0.08	0.18	0.005	0.18	–	99.5(a)	–	0.13	–	0.2
Nickel 201	N02201	0.01	0.18	0.005	0.18	–	99.6(a)	–	0.13	–	0.2
Monel 400	N04400	0.15	1	0.012	0.25	–	66.5(a)	–	31.5	–	1.25
Monel K-500	N05500	0.13	0.75	0.005	0.25	–	66.5(a)	–	29.5	0.6	1
Hastelloy B	N10665	0.05 max	1	–	1	1	61	28	–	–	5
Hastelloy D	–	0.12	0.9	–	9.25	1	82	–	3	–	2
Inconel 600	N06600	0.08	0.5	0.008	0.25	15.5	76.0(a)	–	0.25	–	8
Inconel 800	N08800	0.05	0.75	0.008	0.5	21	32.5	–	0.38	0.38	46
Hastelloy C-276	N10276	0.01	0.5	0.02	0.03	15.5	57	16	–	–	5.5
Inconel 625	N06025	0.05	0.25	0.008	0.25	21.5	61.0(a)	9	–	0.2	2.5
Incoloy 825	N08825	0.03	0.5	0.015	0.25	21.5	42	3	2.25	0.9	30
Hastelloy G	N06030	0.03	1.5	0.02	0.5	22.25	44	6.5	2	–	19.5
20Cb-3	N08020	0.04	1	0.02	0.5	20	34	2.5	3.5	–	–

Mechanical Properties Nickel-Alloy Flanges

Superalloy grade	UNS Equivalent	Yield Strength (in ksi)	Tensile Strength (in ksi)	Elongation %	Rockwell	Brinell
Nickel 200	N02200	15	55	35	–	90-120
Nickel 201	N02201	12	50	35	–	90-120
Monel 400	N04400	25	70	35	–	110-149
Monel K-500	N05500	100	140	17	–	265-346
Hastelloy B-2	N10665	51	110	40	C22	–
Hastelloy D-205	–	49	114	57	C30-39	–
Inconel 600	N06600	30	80	35	–	120-170
Inconel 800	N08800	30	75	30	–	120-184
Hastelloy C-276	N10276	60	115	50	–	184
Inconel 625	N06025	39	98	30	–	180
Incoloy 825	N08825	35	85	30	–	120-180
Hastelloy G-30	N06030	51	100	56	–	–
20Cb-3	N08020	35	80	30	B84-90	160

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Previous Comments

Flosil-betFebruary 27, 2020

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Rahul JainDecember 17, 2020

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Arun KhotFebruary 17, 2021

can you please tell me equivalent material for A694 F60 (which should have almost similar is chemical composition and yield strength.) Thank you.

Kalikund SteelFebruary 8, 2023

Really nice information keep it up.

Rahul MehtaMarch 21, 2023

Its Very Nice Information to read….Good job Keep Posting

VinayAugust 23, 2024

Great article! I was wondering, do you have any recommendations for specific applications where one ASTM material might outperform another? For example, which material would be best for high-pressure systems?

Fabrizio SuteraNovember 12, 2024

Thank you for your positive feedback on the article! In regards to your question about specific applications where one ASTM material might outperform another, it is important to consider the properties and characteristics of each material to determine the best fit for high-pressure systems. For high-pressure systems, materials with excellent strength and corrosion resistance are crucial. ASTM A105 carbon steel flanges are commonly used in high-pressure applications due to their good mechanical properties and resistance to oxidation and scaling at elevated temperatures. They are also cost-effective compared to other materials. However, in more demanding environments with corrosive or high-temperature conditions, alloy and stainless steel flanges such as ASTM A182 and A350 would be preferred. These materials offer enhanced resistance to corrosion, higher strength, and better performance at elevated temperatures. When it comes to extremely corrosive environments, nickel alloy flanges like Inconel, Incoloy, and Hastelloy (UNS S32205) are often chosen. These materials possess exceptional corrosion resistance properties, making them suitable for applications involving acids, alkalis, and seawater. In summary, while ASTM A105 carbon steel flanges are commonly used in high-pressure systems, the selection of the most appropriate material depends on the specific requirements of the application. Considering factors such as pressure, temperature, and corrosive environment will help determine the ideal ASTM material that can outperform others in a given scenario.