The ASME B16.5 standard specifies the materials used for flanges and flanged fittings. These materials are grouped for easier selection and are associated with pressure-temperature ratings.
Materials Required for Flanges and Flanged Fittings
The materials for flanges and flanged fittings are listed in a table with the following restrictions:
Plate and flat bar materials may only be used for blind flanges and reducing flanges without hubs.
Flanges and flanged fittings shall be manufactured as a single piece according to the applicable material specification. This standard does not permit the assembly of multiple parts into the finished product by welding or other means.
Manufacturing Requirements for Forged Flanges
Each forged flange shall be manufactured from a material that is brought as close as possible to the finished shape and size through a compressive hot-working process, consolidating the material to form a wrought structure. During this process, the direction of metal flow should be aligned to best resist the stresses encountered in service.
Materials listed in Section II of the ASME Boiler and Pressure Vessel Code may be used, provided that the requirements of the selected material are identical to or more stringent than those of the ASTM specification for the grade, class, or type of material.
Common Material Categories in ASME B16.5
Group 1 Carbon Steel & Alloy Steel
| Material Group No. | Nominal Designation | Pressure-Temperature Rating Table | Forgings | Castings | Plates |
| 1.1 | C-Si | 2-1.1 | A105 | A216 Gr. WCB | A515 Gr. 70 |
| C-Mn-Si | A350 Gr. LF2 | … | A516 Gr. 70, A537 Cl. 1 | ||
| C-Mn-Si-V | A350 Gr. LF6 Cl. 1 | … | … | ||
| 3½Ni | A350 Gr. LF3 | … | … | ||
| 1.2 | C-Mn-Si | 2-1.2 | … | A216 Gr. WCC | … |
| C-Mn-Si-V | A350 Gr. LF6 Cl. 2 | A352 Gr. LCC, LC2, LC3 | … | ||
| 3½Ni | … | A352 Gr. LC3 | A203 Gr. E | ||
| 1.3 | C-Si | 2-1.3 | … | A352 Gr. LCB | A515 Gr. 65 |
| 2½Ni | … | … | A203 Gr. A | ||
| C-½Mo | … | A217 Gr. WC1 | A204 Gr. B | ||
| 1.4 | C-Si | 2-1.4 | … | … | A515 Gr. 60 |
| C-Mn-Si | A350 Gr. LF1 Cl. 1 | … | A516 Gr. 60 | ||
| 1.5 | C-½Mo | 2-1.5 | A182 Gr. F1 | … | A204 Gr. B |
| 1.7 | Ni-Cr-½Mo | 2-1.7 | A182 Gr. F2 | A217 Gr. WC4 | … |
| ¾Ni-¾Cr-1Mo | … | A217 Gr. WC6 | … | ||
| 1.9 | 1¼Cr-½Mo | 2-1.9 | A182 Gr. F11 Cl. 2 | … | A387 Gr. 11 Cl. 2 |
| 1.1 | 2¼Cr-1Mo | 2-1.10 | A182 Gr. F22 Cl. 3 | A217 Gr. WC9 | A387 Gr. 22 Cl. 2 |
| 1.11 | C-½Mo | 2-1.11 | … | … | A204 Gr. C |
| 1.13 | 5Cr-½Mo | 2-1.13 | A182 Gr. F5a | A217 Gr. C5 | … |
| 1.14 | 9Cr-1Mo-V | 2-1.14 | A182 Gr. F91 Type 1 | A217 Gr. C12A | A387 Gr. 91 Cl. 2 |
| 1.17 | 1Cr-½Mo | 2-1.17 | A182 Gr. F12 Cl. 2 | A217 Gr. C12 | … |
| 1.18 | 9Cr-2W-V | 2-1.18 | A182 Gr. F92 | … | … |
Group 2 Stainless Steel & Duplex Stainless Steel
| Material Group No. | Nominal Designation | Pressure-Temperature Rating Table | Forgings | Castings | Plates |
| 2.1 | 18Cr-8Ni | 2-2.1 | A182 Gr. F304 | A351 Gr. CF3 | A240 Gr. 304 |
| 18Cr–8Ni18Cr-8Ni | A182 Gr. F304H | A351 Gr. CF8 | A240 Gr. 304H | ||
| 2.2 | 16Cr-12Ni-2Mo | 2-2.2 | A182 Gr.F316 | A351 Gr.CF3M | A240 Gr.316 |
| 16Cr-12Ni-2Mo | A182 Gr.F316H | A351 Gr.CF8M | A240 Gr.316H | ||
| 18Cr-13Ni-3Mo | A182 Gr.F317 | … | A240 Gr.317 | ||
| 19Cr-10Ni-3Mo | … | A351 Gr.CG8M | … | ||
| 2.3 | 18Cr-8Ni | 2-2.3 | A182 Gr.F304L | … | A240 Gr.304L |
| 16Cr-12Ni-2Mo | A182 Gr.F316L | … | A240 Gr.316L | ||
| 18Cr-13Ni-3Mo | A182 Gr.F317L | … | … | ||
| 2.4 | 18Cr-10Ni-Ti | 2-2.4 | A182 Gr.F321 | … | A240 Gr.321 |
| 18Cr-10Ni-Ti | A182 Gr.F321H | … | A240 Gr.321H | ||
| 2.5 | 18Cr-10Ni-Cb | 2-2.5 | A182 Gr. F347 | … | A240 Gr. 347 |
| 18Cr-10Ni-Cb | A182 Gr. F347H | … | A240 Gr. 347H | ||
| 18Cr-10Ni-Cb | A182 Gr. F348 | … | A240 Gr. 348 | ||
| 18Cr-10Ni-Cb | A182 Gr. F348H | … | A240 Gr. 348H | ||
| 2.6 | 23Cr-12Ni | 2-2.6 | … | … | A240 Gr. 309H |
| 2.7 | 25Cr-20Ni | 2-2.7 | A182 Gr. F310 | … | A240 Gr. 310H |
| 2.8 | 20Cr-18Ni-6Mo | 2-2.8 | A182 Gr. F44 | A351 Gr. CK3MCuN | A240 Gr. S31254 |
| 22Cr-5Ni-3Mo-N | 2-2.8 | A182 Gr. F51 | – | A240 Gr. S31803 | |
| 25Cr-7Ni-4Mo-N | 2-2.8 | A182 Gr. F53 | – | A240 Gr. 32750 | |
| 24Cr-10Ni-4Mo-V | 2-2.8 | … | A995 Gr. CEBMN | … | |
| 25Cr-5Ni-2Mo-3Cu-N | 2-2.8 | … | A995 Gr. CD4MCuN | … | |
| 25Cr-7Ni-3.5Mo-W-Cb | 2-2.8 | … | A995 Gr. CD3MWCuN | … | |
| 25Cr-7.5Ni-3.5Mo-N-Cu-W | 2-2.8 | A182 Gr. F55 | … | A240 Gr. S32760 | |
| 2.9 | 23Cr-12Ni | 2-2.9 | … | … | A240 Gr. 309S |
| 25Cr-12Ni | 2-2.9 | … | … | A240 Gr. 310S | |
| 2.10 | 25Cr-12Ni | 2-2.10 | … | A351 Gr. CH8 | … |
| 25Cr-12Ni | 2-2.10 | … | A351 Gr. CH20 | … | |
| 2.11 | 18Cr-10Ni-Cb | 2-2.11 | … | A351 Gr. CF8C | … |
| 2.12 | 25Cr-20Ni | 2-2.12 | … | A351 Gr. CK20 | … |
Group 3 High Alloy Steel
| Material Group No. | Nominal Designation | Pressure-Temperature Rating Table | Forgings | Castings | Plates |
| 3.1 | 35Ni-35Fe-20Cr-Cb | 2-3.1 | A182 Gr.N08020 | … | A182 Gr.N08020 |
| 3.2 | 99.0Ni | 2-3.2 | B564 Gr.N02200 | … | B162 Gr.N02200 |
| 3.3 | 99.0Ni-Low C | 2-3.3 | … | … | B162 Gr.NO2201 |
| 3.4 | 67Ni-30Cu | 2-3.4 | B564 Gr.N04400 | … | B127 Gr.N04400 |
| 3.5 | 72Ni-15Cr-8Fe | 2-3.5 | B564 Gr.N06600 | … | B168 Gr.N06600 |
| 3.6 | 33Ni-42Fe-21Cr | 2-3.6 | A182 Gr.N08800 | … | A182 Gr.N08800 |
| 3.7 | 65Ni-28Mo-2Fe | 2-3.7 | B462 Gr.N10665 | … | B333 Gr.N10665 |
| 64Ni-29.5Mo-2Cr-2Fe-Mn-W | B462 Gr.N10675 | … | B333 Gr.N10675 | ||
| 3.8 | 54Ni-16Mo-15Cr | 2-3.8 | B462 Gr.N10276 | … | B575 Gr.N10276 |
| 60Ni-22Cr-9Mo-3.5Cb | B564 Gr.N06625 | … | B443 Gr.N06625 | ||
| 62Ni-28Mo-5Fe | … | … | B333 Gr.N10001 | ||
| 70Ni-16Mo-7Cr-5Fe | … | … | B434 Gr.N10003 | ||
| 61Ni-16Mo-16Cr | … | … | B575 Gr.N06455 | ||
| 42Ni-21.5Cr-3Mo-2.3Cu | B564 Gr.N08825 | … | B424 Gr.N08825 | ||
| 55Ni-21Cr-13.5Mo | B462 Gr.N06022 | … | B575 Gr.N06022 | ||
| 55Ni-23Cr-16Mo-1.6Cu | B462 Gr.N06200 | … | B575 Gr.N06200 | ||
| 3.9 | 47Ni-22Cr-9Mo-I8Fe | 2-3.9 | B572 Gr.N06002 | … | B435 Gr.N06002 |
| 21Ni-30Fe-22Cr-18Co-3Mo-3W | B572 Gr.R30556 | … | B435 Gr.R30556 | ||
| 3.10 | 25Ni-47Fe-21Cr-5Mo | 2-3.10 | … | … | B599 Gr.N08700 |
| 3.11 | 44Fe-25Ni-21Cr-Mo | 2-3.11 | A182 Gr.N08904 | … | A240 Gr.N08904 |
| 3.12 | 26Ni-43Fe-22Cr-5Mo | 2-3.12 | … | … | B620 Gr.N08320 |
| 47Ni-22Cr-20Fe-7Mo | … | … | B582 Gr.N06985 | ||
| 46Fe-24Ni-21Cr-6Mo-Cu-N | A182 Gr.N08367 | A351 Gr.CN3MN | B688 Gr.N08367 | ||
| 46Fe-24Ni-21Cr-6Mo-Cu-N | B462 Gr.N08367 | A351 Gr.CN3MN | B688 Gr.N08367 | ||
| 3.13 | 49Ni-25Cr-18Fe-6Mo | 2-3.13 | … | … | B582 Gr.N06975 |
| Ni-Fe-Cr-Mo-Cu-Low C | B564 Gr.N08031 | … | B625 Gr.N08031 | ||
| 3.14 | 47Ni–22Cr–19Fe–6Mo | 2-3.14 | … | … | B582 Gr. N06007 |
| 40Ni–29Cr–15Fe–5Mo | B462 Gr. N06030 | … | B582 Gr. N06030 | ||
| 58Ni–33Cr–8Mo | B462 Gr. N06035 | … | B575 Gr. N06035 | ||
| 3.15 | 42Ni–42Fe–21Cr | 2-3.15 | A182 Gr. N08810 | … | A240 Gr. N08810 |
| 42Ni–42Fe–21Cr | B564 Gr. N08810 | … | B409 Gr. N08810 | ||
| 3.16 | 35Ni–19Cr–1¼Si | 2-3.16 | B511 Gr. N08330 | … | B536 Gr. N08330 |
| 3.17 | 29Ni–20.5Cr–3.5Cu–2.5Mo | 2-3.17 | … | A351 Gr. CN7M | … |
| 3.19 | 57Ni–22Cr–14W–2Mo–La | 2-3.19 | B564 Gr. N06230 | … | B435 Gr. N06230 |
Key Factors in Material Selection
Temperature Range: The material should be suitable for the operating temperature range of the piping system (e.g., high or low temperatures).
Pressure Rating: The material group is associated with the pressure-temperature ratings table.
Corrosion Resistance: Materials should be selected based on the system’s media (e.g., acids, bases, saltwater).
Mechanical Properties: Consider yield strength, tensile strength, toughness, and other mechanical properties.
