Carbon steel flange materials: ASTM A105 and ASTM A350 chemical composition, pressure rating, and mechanical properties.

 

ASTM A105, A350, A694 CHEMICAL COMPOSITION

The chemical composition of carbon steel flange materials ASTM A105 (high-temperature service) and ASTM A350 LF1, LF2, LF3 (low-temperature service, i.e. LTCS).

ASTM A105 (HIGH-TEMPERATURE CARBON STEEL FLANGE)

Chemical Composition of ASTM A105 (in %)
Element C Mn P S Si Cu Ni Cr Mo V
0.35 max 0.60-1.05 0.035 max 0.040
max
0.10-0.35 0.40
max (1)
0.40
max (1)
0.30
max (1-2)
0.12
max (1-2)
0.08
max

Notes:

  1. The total of Cu, Ni, Niobium, Moly, and Vanadium shall not exceed 1.00%.
  2. The sum of Niobium and Molybdenum shall not exceed 0.32%.

 

ASTM A350 LF1 (LOW-TEMPERATURE CARBON STEEL FLANGE)

C% Mn% Si% S% P% Cr% Ni%
0.30 max 0.6/1.35 .15/.30 .040 max .035 max 0.30 max 0.40 max

 

ASTM A350 LF2

C% Mn% Si% S% P% Cr% Ni%
0.30 max 0.6/1.35 .15/.30 .040 max .035 max 0.30 max 0.40 max

 

ASTM A350 LF3 

C% Mn% Si% S% P% Cr% Ni%
0.20 max 0.90 .20/.35 .040 max .035 max 0.30 max 3.3/3.7

 

ASTM A694 F42 (HIGH YIELD CARBON STEEL FLANGE)

Grade 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

Grade C Mn P S Si
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

Grade C Mn P S Si
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

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

 

ASTM A105, A350 PRESSURE RATING

(Max working pressure of carbon steel flange ASTM A105 and ASTM A350 – by Class, in bar)

TEMP. C 150# 300# 400# 600# 900# 1500# 2500#
-29 to 38 19.6 51.1 68.1 102.1 153.2 255.3 425.5
50 19.2 50.1 66.8 100.2 150.4 250.6 417.7
100 17.7 46.6 62.1 93.2 139.8 233 388.3
150 15.8 45.1 60.1 90.2 135.2 225.4 375.6
200 13.8 43.8 58.4 87.6 131.4 219 365
250 12.1 41.9 55.9 83.9 125.8 209.7 349.5
300 10.2 39.8 53.1 79.6 119.5 199.1 331.8
325 9.3 38.7 51.6 77.4 116.1 193.6 322.6
350 8.4 37.6 50.1 75.1 112.7 187.8 313
375 7.4 36.4 48.5 72.7 109.1 181.8 303.1
400 6.5 34.7 46.3 69.4 104.2 173.6 289.3
425 5.5 28.8 38.4 57.5 86.3 143.8 239.7
450 4.6 23 30.7 46 69 115 191.7
475 3.7 17.4 23.2 34.9 52.3 87.2 145.3
500 2.8 11.8 15.7 23.5 35.3 58.8 97.9
538 1.4 5.9 7.9 11.8 17.7 29.5 49.2

To learn more about flange pressure rating, read this article.

 

ASTM A105, A350, A694 MECHANICAL PROPERTIES

ASTM A105, A350 FLANGE MATERIAL

Mechanical 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 15/12 ft-lbs
CVN at -50℉ 20/16 joules

 

ASTM A694 FLANGE MATERIAL

ASTM A694 Flange Material Grade Min Yield Strength (0.2 % Offset), in ksi [MPa] MinTensile Strength
in ksi [MPa]
Elongation in 2 in. or 50 mm, min %
ASTM A694 F42 42 [290] 60 [415] 20
ASTM A694 F46 46 [315] 60 [415] 20
ASTM A694 F48 48 [330] 62 [425] 20
ASTM A694 F50 50 [345] 64 [440] 20
ASTM A694 F52 52 [360] 66 [455] 20
ASTM A694 F56 56 [385] 68 [470] 20
ASTM A694 F60 60 [415] 75 [515] 20
ASTM A694 F65 65 [450] 77 [530] 20
ASTM A694 F70 70 [485] 82 [565] 18

 

ASTM A105, A350 RECOMMENDED SERVICE

The flange material selection depends on the temperature and the pressure of the piping system and the type of fluid to be conveyed. In the tables below, we report the recommended service for common ASTM forged grades.

MATERIAL MATERIAL GROUP RECOMMENDED SERVICE
A105 Carbon Steel General service such as oil, oil vapor, gas, steam and water at temperatures -20°F to 1000°F (-28°C to 537°C)
A350-LF2 CL1 Low-Temperature Carbon Steel (LTCS) Low-temperature service down to -50°F and not above 650°F (-46°C and not above 343°C)
A182-F11 CL2 1 1/4% Cr, 1/2% Mo Alloy Steel High temperatures service from -20°F to 1100°F to minimize graphitization (-28°C to 593§C)
A182-F22 CL3 2 1/4% Cr, 1% Mo Alloy Steel High-temperature services requiring greater strength than F11 at temperatures from -20°F to 1100°F (-28°C to 593°C)
A182-F5 5% Cr, 1/2% Mo Alloy Steel Corrosive/erosive refinery service requiring resistance at temperatures from -20°F to 1100§F (-28°C to 590°C)
A182-F9 9% Cr, 1% Mo Alloy Steel Fluids with higher Sulphur content to fight oxidation to 1100oF (593°C)

 

ASTM vs. EN CARBON STEEL FLANGE MATERIALS

Flanges Material Grades: Comparison European and American Standards
Material number EN ASTM
High-Temperature Carbon Steel Flange Materials
1.0038 RSt 37-2 S235JR
1.0570 St 52-3 S355J2 (1.0577)
1.0460 C 22.8 P250GH
1.0432 C 21 A 105
1.0352 – P245GH
Low-Temperature Carbon Steel (LTCS) Flange Materials
1.5637 10 Ni 14 12Ni14 A 350 Grade LF3
1.0566 TStE 355 P355QH1 (1.0571) A 350 Grade LF2
High Yield Carbon Steel Flange Materials
1.0486 StE 285 A 694 Grade F42
1.0562 StE 355 P355N A 694 Grade F52
1.8902 StE 420 P420N A 694 Grade F60
1.8905 StE 460 P460N A 694 Grade F70