Materials for Flanges

CARBON STEEL FLANGES

The chemical composition and the mechanical properties of the three main carbon steel flanges material 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
Carbon Steel Flange Materials

CHEMICAL COMPOSITION ASTM A105, A350, A694

ASTM A105 (High-temperature carbon steel flange material)

CMnPSSiCuNiCrMoV
A105–0.60––0.10–––
0.351.050.0350.0400.350.400.400.300.120.08

ASTM A350 (Low-Temperature carbon steel flange material)

C%Mn%Si%S%P%Cr%Ni%
A350 LF10.30 max0.6/1.35.15/.30.040 max.035 max0.30 max0.40 max
A350 LF20.30 max0.6/1.35.15/.30.040 max.035 max0.30 max0.40 max
A350 LF30.20 max0.9.20/.35.040 max.035 max0.30 max3.3/3.7

ASTM A694 (High-yield carbon steel flanges)

CMnPSSi
ASTM A694 F420.26-0.2651.60-1.640.025-0.0300.025-0.0300.15-0.35
ASTM A694 F520.26-0.2651.60-1.640.025-0.0300.025-0.0300.15-0.35
ASTM A694 F600.26-0.2651.60-1.640.025-0.0300.025-0.0300.15-0.35
ASTM A694 F650.26-0.2651.60-1.640.025-0.0300.025-0.0300.15-0.35

MECHANICAL PROPERTIES A105, A350, A694

ASTM A105 (High-temperature carbon steel flange material)

PropertyASTM A105ASTM A350-LF2
Tensile Strength Min, psi70,00070,000-95,000
Tensile Strength Min, N/mm²485485-655
Yield Strength Min, psi36,00036,000
Yield Strength Min, N/mm²250250
Elongation (%)2222
Reduction of Area (%)3030
Hardness, maximum18715/12 ft-lbs
CVN at -50℉20/16 joules

ASTM A694 (High-yield carbon steel flanges)

ASTM A694 Flange Material GradeMin Yield Strength (0.2 % Offset), in ksi [MPa]MinTensile StrengthElongation in 2 in. or 50 mm, min %
in ksi [MPa]
A694 F4242 [290]60 [415]20
A694 F4646 [315]60 [415]20
A694 F4848 [330]62 [425]20
A694 F5050 [345]64 [440]20
A694 F5252 [360]66 [455]20
A694 F5656 [385]68 [470]20
A694 F6060 [415]75 [515]20
A694 F6565 [450]77 [530]20
A694 F7070 [485]82 [565]18

ALLOY STEEL FLANGES

Alloy flange materials (chrome-moly) have higher chrome and molybdenum content than carbon steel flanges. Alloy steel flange materials suit high temperature and high-pressure applications and improved resistance to corrosion when compared to regular carbon steel flanges grades.

Alloy Steel Flange Materials
alloy steel flanges ASTM A182

ASTM A182 alloy flanges are extremely ductile, strong and tough and easy to weld and offer oxidation and scaling resistance. These grades match with ASTM A335 alloy steel pipes.

CHEMICAL COMPOSITION ASTM A182 F5, F9, F11, F22

ELEMENT & PROPERTIESLOW ALLOY STEELMEDIUM ALLOY STEEL
F11 CL2F22 CL3F5F9
CARBON0.10-0.200.05-0.150.15 MAX0.15 MAX
MANGANESE0.30-0.800.30-0.600.30-0.600.30-0.60
PHOSPHORUS MAX0.0400.0400.030.030
SULFUR MAX0.0400.0400.030.030
SILICON0.50-1.000.50 MAX0.50 MAX0.50-1.00
NICKEL MAX––0.50–
CHROMIUM1.00-1.502.00-2.504.00-6.008.0-10.0
MOLYBDENUM0.44-0.650.87-1.130.44-0.650.90-1.10
OPPER MA––––
COLUMBIUM MAX––––
VANADIUM MAX––––

MECHANICAL PROPERTIES A182

ELEMENT & PROPERTIESLOW ALLOY STEELMEDIUM ALLOY STEEL
F11 CL2F22 CL3F5F9
TENSILE STRENGTH PSI (MPA)70,000 (485)75,000 (515)70,000 (485)85,000 (585)
YIELD STRENGTH PSI MIN40,000 (275)45,000 (310)40,000 (275)55,000 (380)
ELONGATION 2” % MIN20202020
REDUCTION AREA % MIN30303540
HARDNESS (HB) MAX*143 ~ 207156 ~ 207143 ~ 217179 ~ 217

Recommended service for alloy steel flange material grades ASTM A182:

ASTM A182 ALLOY STEEL FLANGETRADE DESIGNATIONRECOMMENDED SERVICE
A182 F1C-1/2 Mo Low Alloy SteelNon-corrosive applications Including water, oil, and gases at temperatures between -29 ~ 593ºC* (Not prolonged use > 470ºC).
A182 F20.75% Ni; Mo; 0.75% Cr Low Alloy SteelNon-corrosive applications including water, oil, and gases at temperatures F2:-29ºC ~ 538ºC, WC5: -29ºC ~ 575ºC
A182 F111 1/4% Chrome; 1/2% Moly Low Alloy SteelNon-corrosive applications including water, oil, and gases at temperatures between -30ºC (-20ºF) and +593ºC (+1100ºF).
A182 F222 1/4% Chrome Low Alloy SteelNon-corrosive applications including water, oil, and gases at temperatures between -30ºC (-20ºF) and +593ºC (+1100ºF).
A182 F5/F5a5% Chrome; 1/2% Moly, Medium Alloy SteelMild corrosive or erosive applications as well as non-corrosive applications at temperatures between -30ºC (-20ºF) and +650ºC (+1200ºF).
A182 F99% Chrome; 1% Moly, Medium Alloy SteelMild corrosive or erosive applications as well as non-corrosive applications at temperatures between -30ºC (-20ºF) and +650ºC (+1200ºF).
A182 F919% Chrome; 1% Moly; V-N, Medium Alloy SteelMild corrosive or erosive applications as well as non-corrosive applications at temperatures between -30ºC (-20ºF) and +650ºC (+1200ºF).

STAINLESS STEEL FLANGES

The key elements that differentiate stainless steel materials for flanges, compared to other grades, are the Nickel (Ni), Chrome (Cr), and Molybdenum content (Mo). The price for these metals fluctuates daily on the London Metal Exchange (Nickel, Moly) and on the ferroalloy market (ferrochrome).

Stainless Steel Flange Materials ASTM A182
Stainless steel flanges ASTM A182

CHEMICAL COMPOSITION ASTM A182 F304/F316/F321

ASTM A182 Stainless Steel Flanges Materials Composition, %
ASTM A182 GRADECMnPSSiNiCrMoNbTiOthers
F304(1)0.082.00.0450.0301.08.0-11.018.0-20.0
F304H0.04-0.102.00.0450.0301.08.0-11.018.0-20.0
F304L(1)0.0302.00.0450.0301.08.0-13.018.0-20.0
F304N(2)0.082.00.0450.0301.08.0-10.518.0-20.0
F304LN(2)0.0302.00.0450.0301.08.0-10.518.0-20.0
F309H0.04-0.102.00.0450.0301.012.0-15.022.0-24.0
F3100.252.00.0450.0301.019.0-22.024.0-26.0
F310H0.04-0.102.00.0450.0301.019.0-22.024.0-26.0
F310MoLN0.0302.00.0300.0150.4021.0-23.024.0-26.02.0-3.0N 0.10-0.16
F3160.082.00.0450.0301.010.0-14.016.0-18.02.0-3.0
F316H0.04-0.102.00.0450.0301.010.0-14.016.0-18.02.0-3.0
F316L(1)0.0302.00.0450.0301.010.0-15.016.0-18.02.0-3.0
F316N(2)0.082.00.0450.0301.011.0-14.016.0-18.02.0-3.0
F316LN(2)0.0302.00.0450.0301.011.0-14.016.0-18.02.0-3.0
F316Ti0.082.00.0450.0301.010.0-14.016.0-18.02.0-3.0(3)N 0.10 max
F3170.082.00.0450.0301.011.0-15.018.0-20.03.0-4.0
F317L0.0302.00.0450.0301.011.0-15.018.0-20.03.0-4.0
F3210.082.00.0450.0301.09.0-12.017.0-19.0(4)
F321H0.04-0.102.00.0450.0301.09.0-12.017.0-19.0(5)
F3470.082.00.0450.0301.09.0-13.017.0-20.0(6)
F347H0.04-0.102.00.0450.0301.09.0-13.017.0-20.0(7)
F3480.082.00.0450.0301.09.0-13.017.0-20.0(6)Co 0.20
Ta 0.10
F348H0.04-0.102.00.0450.0301.09.0-13.017.0-20.0(7)Co 0.20
Ta 0.10

Notes:

  1. Grades F304, F304L, F316, and F316L shall have a maximum Nitrogen of 0.10%.
  2. Grades F304N, F316N, F304LN, and F316LN shall have a Nitrogen of 0.10 to 0.16%.
  3. Grade F316Ti shall have a Titanium content five times above the Carbon plus Nitrogen and not more than 0.70%.
  4. Grade F321 shall have a Titanium content five times above the Carbon and not more than 0.70%.
  5. Grade F321H shall have a Titanium content four times above the Carbon and not more than 0.70%.
  6. Grades F347 and F348 shall have a Niobium content ten times above the Carbon and not more than 1.10%.
  7. 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 GradeMinimum Tensile Strength
in MPa		Minimum Yield point
in Mpa		Minimum Elongation
in %		Minimum Reduction of in
min, %
ASTM A182 F3045152053050
ASTM A182 F304L4851703050
ASTM A182 F3165152053050
ASTM A182 F316L4851703050
ASTM A182 F3215152053050

Recommended service for stainless steel flange materials:

MATERIALMATERIAL GROUPRECOMMENDED SERVICE
A182-F30418% Cr, 8% Ni Stainless SteelCorrosive services and atmospheres from -450°F to 1000°F (-268°C to 537°C)
A182-F31618% Cr, 8% Ni, 2% Mo Stainless SteelHigh 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 European and American Standards
Material numberENASTM
Stainless Steel Flange Materials
1.4541 X 6 CrNiTi 18 10X6CrNiTi18-10A 182 Grade F321
1.4571 X 6 CrNiMoTi 17 12 2X6CrNiMoTi17-12-2A 182 Grade F316Ti
1.4301 X 5 CrNi 18 10X5CrNi18-10A 182 Grade F304
1.4306 X 2 CrNi 19 11–A 182 Grade F304L
1.4307 –X2CrNi18-9A 182 Grade F304L
1.4401 X 5 CrNiMo 17 12 2X5CrNiMo17-12-2A 182 Grade F316
1.4404 X 2 CrNiMo 17 13 2X2CrNiMo17-12-2A 182 Grade F316L
1.4462 X 2 CrNiMoN 22 5 3X2CrNiMoN22-5-3A 182 Grade F51 (Duplex)
1.4529 X 1 NiCrMoCuN 25 20 6X1NiCrMoCuN25-20-7UNS N 08926
1.4539 X 1 NiCrMoCuN 25 20 5X1NiCrMoCu25-20-5A 182 Grade F904L
1.4547 –X1CrNiMoCuN20-18-7UNS S 3125

DUPLEX FLANGES

Duplex steel (ASTM A182 2205) is an extremely corrosion resistant, work hardenable stainless steel, whose microstructure consists of a mixture of austenite and ferrite phases.

Duplex Flange ASTM A182 UNS S31803 UNS S32205
Duplex Flange ASTM A182 UNS S31803 UNS S32205

Due to this particular chemical and physical composition, duplex stainless steel UNS S31803 features the properties characteristic of both types of stainless steel materials (ferritic and austenitic).

Generally speaking, duplex stainless steel is way tougher than ferritic stainless steels, has a superior strength than austenitic steels (series 300 and 400) and has superior resistance to corrosion when compared to SS304 and SS316 (high intragranular corrosion, also in chloride and sulfide environments).

Whilst austenitic stainless steels are non-magnetic, duplex stainless steel shows magnetic properties.

Duplex and super duplex flanges match with ASTM A790 seamless pipes (or A928 welded duplex pipes).

CHEMICAL COMPOSITION ASTM A182 DUPLEX AND SUPER DUPLEX

%Duplex 2205
(ASTM A182 UNS S31803 – UNS S32205)		Super Duplex
ASTM A182 UNS S32750 – 32760)
C0-0.030.03 max
Mn2.01.5
Si1.00.8
P0-0.030.035
S0-0.020.02
Cr21-2324-26
Mo2.5-3.53.0-5.0
Ni4.5-6.55.5-8.0
N0.08-0.20.2-0.35
Cu–0.5-3.0

The most widely used grade for Duplex flange is 2205, due to its superior resistance to corrosion and mechanical strength.

The designation “2205” is related to the chemical composition of this material, which features 22% of chromium and 5% of nickel.

Super Duplex flange show an even superior strength and a higher corrosion resistance than standard duplex steel (and austenitic grades, of course).

The main difference between a duplex and a super duplex grade is the addition of copper to the alloy (in addition to increased amounts of Chromium, Moly, and Nickel).

The addition of copper gives Super Duplex Stainless Steel an improved resistance to hot chlorides and strong reducing acids, like sulphuric acid, compared to a standard Duplex grade.

Whilst UNS S31803, UNS 32205 (duplex) and UNS S32750, UNS S32760 are standard designations, most manufacturers of superalloys attribute proprietary names to these steels (example UR52N+ is a Usinor/Arcelor Super Duplex steel, Ferralium, Zeron, Sandvik SAF 2205 22Cr, etc).

MECHANICAL PROPERTIES A182 DUPLEX AND SUPER DUPLEX

Mechanical PropertiesDuplex 2205
(ASTM A182 UNS S31803 – UNS S32205)		Super Duplex
ASTM A182 UNS S32750 – 32760)
Tensile Strength (in MPa)620770
Proof Stress 0.2% (in MPa)450550
A5 Elongation (in %)2525
Physical AttributeDuplex 2205
(ASTM A182 UNS S31803 – UNS S32205)		Super Duplex
ASTM A182 UNS S32750 – 32760)
Density (g.cm3)7.8057.810
Modulus of Elasticity (GPa)200205
Electrical Resistivity (Ω.m)0.085×10-60.085×10-6
Thermal Conductivity (W/m.K)19 at 100°C17 at 100°C
Thermal Expansion (m/m.K)13.7×10-6 to 100°C13.5×10-6 to 200°C

The significant addition of Chromium in Duplex Steel grades, that protects the alloy against corrosion, is a source of steel embrittlement at temperatures over about 300°C. However, at lower temperatures duplex steels show better ductility properties than ferritic and martensitic stainless steels (they can easily be used at a temperature below -50 C°).

NICKEL ALLOY FLANGES

ASTM SPECIFICATIONS FOR NICKEL ALLOY FLANGES

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 GradeUNS EquivalentAlloy Composition
CMnSSiCrNiMoCuTiFe
Nickel 200N022000.080.180.0050.18…99.5(a)…0.13…0.2
Nickel 201N022010.010.180.0050.18…99.6(a)…0.13…0.2
Monel 400N044000.1510.0120.25…66.5(a)…31.5…1.25
Monel K-500N055000.130.750.0050.25…66.5(a)…29.50.61
Hastelloy BN106650.05 max1…116128……5
Hastelloy D–0.120.9…9.25182…3…2
Inconel 600N066000.080.50.0080.2515.576.0(a)…0.25…8
Inconel 800N088000.050.750.0080.52132.5…0.380.3846
Hastelloy C-276N102760.010.50.020.0315.55716……5.5
Inconel 625N060250.050.250.0080.2521.561.0(a)9…0.22.5
Incoloy 825N088250.030.50.0150.2521.54232.250.930
Hastelloy GN060300.031.50.020.522.25446.52…19.5
20Cb-3N080200.0410.020.520342.53.5……

MECHANICAL PROPERTIES NICKEL-ALLOY FLANGES

Superalloy gradeUNS EquivalentYield Strength (in 
ksi)		Tensile Strength (in ksi)Elongation %RockwellBrinell
Nickel 200N02200155535–90-120
Nickel 201N02201125035–90-120
Monel 400N04400257035–110-149
Monel K-500N0550010014017–265-346
Hastelloy B-2N106655111040C22–
Hastelloy D-205–4911457C30-39–
Inconel 600N06600308035–120-170
Inconel 800N08800307530–120-184
Hastelloy C-276N102766011550184
Inconel 625N06025399830–180
Incoloy 825N08825358530–120-180
Hastelloy G-30N060305110056––
20Cb-3N08020358030B84-90160