ASME B16.5 · Standard reference
ASME B16.5-2025 material groups and bolting tables
Table 1.1-1 is the master material list of ASME B16.5-2025. For every accepted material it gives four things: the material group number used by the pressure–temperature tables, the nominal chemical designation, the rating table that governs the group, and the ASTM specifications accepted for forgings, castings and plates. The table runs from Group 1.1 to Group 3.19 across printed pages 5 to 7 — 116 rows in this edition, because many groups accept several specifications for the same nominal designation.
The group number is the link between the material tables and the rating tables. A Group 1.1 flange is rated from Tables 2-1.1 / 2-1.1C, a Group 2.13 flange from 2-2.13 / 2-2.13C, and so on; the C-suffixed table is the U.S. Customary companion of the SI table. Group 1 covers carbon, carbon-manganese and low-alloy steels, Group 2 the stainless and duplex steels, and Group 3 the nickel and special alloys. Plate materials are restricted to blind flanges and reducing flanges without hubs (para. 5.1 and General Note (b)).
Two companion tables complete the material section. Table 1.1-2 lists recommended bolting in four strength categories — high strength, intermediate strength, low strength, and nickel and special alloy — with a notes column that carries grade-specific limits. Table 1.1-3 recommends bolt, stud, nut and thread standards for carbon and alloy steel bolting. The 2025 edition revised Table 1.1-1 and Table 1.1-2 (adding A320 L7M, B511, B572 and B637 bolting), so the lists below are the current ones.
- Standard
- ASME B16.5-2025
- Table 1.1-1
- 116 rows, Groups 1.1–3.19
- Group 1
- Carbon, C-Mn and low-alloy steels
- Group 2
- Stainless and duplex steels
- Group 3
- Nickel and special alloys
- Bolting categories
- 4 (Tables 1.1-2 and 1.1-3)
How to read Table 1.1-1
- Column 1 is the material group number. It is the index used throughout Section 2 of the standard, not a quality or strength ranking. The numbering is not consecutive: Groups 1.6, 1.8, 1.12, 1.16 and 3.18 do not appear in the 2025 table.
- Column 2 is a nominal chemical designation (C-Si, 16Cr-12Ni-2Mo, 67Ni-30Cu), not a trade name. The same designation can appear more than once when different product forms are accepted.
- Column 3 names the pressure–temperature rating table for the group. Add a C for the U.S. Customary version: Group 2.13 is rated from Table 2-2.13 in SI units and Table 2-2.13C in U.S. Customary units.
- Columns 4 to 6 list the ASTM specifications the standard accepts by product form. Where the standard prints an ellipsis the cell is shown here as "—".
- Plate materials are listed only for blind flanges and reducing flanges without hubs; additional plate materials in ASME B16.34 may be used with the corresponding B16.34 Standard Class ratings (General Note (b)).
- Materials to ASME Boiler and Pressure Vessel Code, Section II may be used in place of a listed ASTM specification where the ASME requirements are identical to or more stringent than the ASTM ones (Note (1) to Table 1.1-1).
- Temperature limits belong to the rating tables, not to this list: General Note (a) sends the reader to the notes under Tables 2-1.1C through 2-3.17C.
Table 1.1-1 — Group 1 materials
Rows are listed in the order printed in Table 1.1-1, including the cases where a group spans several rows because it accepts several specifications for one product form.
B16.5 · ASME B16.5-2025
| Group | Nominal designation | P–T rating table | Forgings | Castings | Plates |
|---|---|---|---|---|---|
| 1.1 | C-Si | 2-1.1 | A105 | A216 Gr. WCB | A515 Gr. 70 |
| 1.1 | C-Mn-Si | 2-1.1 | A350 Gr. LF2 | — | A516 Gr. 70 |
| 1.1 | C-Mn-Si | 2-1.1 | — | — | A537 Cl. 1 |
| 1.1 | C-Mn-Si-V | 2-1.1 | A350 Gr. LF6 Cl. 1 | — | — |
| 1.1 | 3½Ni | 2-1.1 | A350 Gr. LF3 | — | — |
| 1.2 | C-Mn-Si | 2-1.2 | — | A216 Gr. WCC | — |
| 1.2 | C-Mn-Si | 2-1.2 | — | A352 Gr. LCC | — |
| 1.2 | C-Mn-Si-V | 2-1.2 | A350 Gr. LF6 Cl. 2 | — | — |
| 1.2 | 2½Ni | 2-1.2 | — | A352 Gr. LC2 | A203 Gr. B |
| 1.2 | 3½Ni | 2-1.2 | — | A352 Gr. LC3 | A203 Gr. E |
| 1.3 | C-Si | 2-1.3 | — | A352 Gr. LCB | A515 Gr. 65 |
| 1.3 | C-Mn-Si | 2-1.3 | — | — | A516 Gr. 65 |
| 1.3 | 2½Ni | 2-1.3 | — | — | A203 Gr. A |
| 1.3 | 3½Ni | 2-1.3 | — | — | A203 Gr. D |
| 1.3 | C-½Mo | 2-1.3 | — | A217 Gr. WC1 | — |
| 1.3 | C-½Mo | 2-1.3 | — | A352 Gr. LC1 | — |
| 1.4 | C-Si | 2-1.4 | — | — | A515 Gr. 60 |
| 1.4 | C-Mn-Si | 2-1.4 | A350 Gr. LF1 Cl. 1 | — | A516 Gr. 60 |
| 1.5 | C-½Mo | 2-1.5 | A182 Gr. F1 | — | A204 Gr. A |
| 1.5 | C-½Mo | 2-1.5 | — | — | A204 Gr. B |
| 1.7 | ½Cr-½Mo | 2-1.7 | A182 Gr. F2 | — | — |
| 1.7 | Ni-½Cr-½Mo | 2-1.7 | — | A217 Gr. WC4 | — |
| 1.7 | ¾Ni-¾Cr-1Mo | 2-1.7 | — | A217 Gr. WC5 | — |
| 1.9 | 1¼Cr-½Mo | 2-1.9 | — | A217 Gr. WC6 | — |
| 1.9 | 1¼Cr-½Mo-Si | 2-1.9 | A182 Gr. F11 Cl. 2 | — | A387 Gr. 11 Cl. 2 |
| 1.10 | 2¼Cr-1Mo | 2-1.10 | A182 Gr. F22 Cl. 3 | A217 Gr. WC9 | A387 Gr. 22 Cl. 2 |
| 1.11 | 3Cr-1Mo | 2-1.11 | A182 Gr. F21 | — | A387 Gr. 21 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 | 2-1.14 | A182 Gr. F9 | A217 Gr. C12 | — |
| 1.15 | 9Cr-1Mo-V | 2-1.15 | 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 | — | — |
| 1.17 | 5Cr-½Mo | 2-1.17 | A182 Gr. F5 | — | — |
| 1.18 | 9Cr-2W-V | 2-1.18 | A182 Gr. F92 | — | — |
The group number is the standard's material-group index, not a ranking. Read the working pressure for the row from the pressure–temperature table named in the third column; the C-suffixed companion gives the same group in U.S. Customary units. "—" marks a product form for which the standard lists no specification.
Table 1.1-1 — Group 2 materials
Rows are listed in the order printed in Table 1.1-1, including the cases where a group spans several rows because it accepts several specifications for one product form.
B16.5 · ASME B16.5-2025
| Group | Nominal designation | P–T rating table | Forgings | Castings | Plates |
|---|---|---|---|---|---|
| 2.1 | 18Cr-8Ni | 2-2.1 | A182 Gr. F304 | A351 Gr. CF3 | A240 Gr. 304 |
| 2.1 | 18Cr-8Ni | 2-2.1 | 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 |
| 2.2 | 16Cr-12Ni-2Mo | 2-2.2 | A182 Gr. F316H | A351 Gr. CF8M | A240 Gr. 316H |
| 2.2 | 18Cr-13Ni-3Mo | 2-2.2 | A182 Gr. F317 | — | A240 Gr. 317 |
| 2.2 | 19Cr-10Ni-3Mo | 2-2.2 | — | A351 Gr. CG8M | — |
| 2.3 | 18Cr-8Ni | 2-2.3 | A182 Gr. F304L | — | A240 Gr. 304L |
| 2.3 | 16Cr-12Ni-2Mo | 2-2.3 | A182 Gr. F316L | — | A240 Gr. 316L |
| 2.3 | 18Cr-13Ni-3Mo | 2-2.3 | A182 Gr. F317L | — | — |
| 2.4 | 18Cr-10Ni-Ti | 2-2.4 | A182 Gr. F321 | — | A240 Gr. 321 |
| 2.4 | 18Cr-10Ni-Ti | 2-2.4 | A182 Gr. F321H | — | A240 Gr. 321H |
| 2.5 | 18Cr-10Ni-Cb | 2-2.5 | A182 Gr. F347 | — | A240 Gr. 347 |
| 2.5 | 18Cr-10Ni-Cb | 2-2.5 | A182 Gr. F347H | — | A240 Gr. 347H |
| 2.5 | 18Cr-10Ni-Cb | 2-2.5 | A182 Gr. F348 | — | A240 Gr. 348 |
| 2.5 | 18Cr-10Ni-Cb | 2-2.5 | 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. 310H | — | A240 Gr. 310H |
| 2.8 | 20Cr-18Ni-6Mo | 2-2.8 | A182 Gr. F44 | A351 Gr. CK3MCuN | A240 Gr. S31254 |
| 2.9 | 23Cr-12Ni | 2-2.9 | — | — | A240 Gr. 309S |
| 2.9 | 25Cr-12Ni | 2-2.9 | — | — | A240 Gr. 310S |
| 2.10 | 25Cr-12Ni | 2-2.10 | — | A351 Gr. CH8 | — |
| 2.10 | 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 | — |
| 2.13 | 22Cr-5Ni-3Mo-N | 2-2.13 | A182 Gr. F51 | A995 Gr. CD3MN (4A) | A240 Gr. S31803 |
| 2.13 | 22Cr-5Ni-3Mo-N | 2-2.13 | A182 Gr. F60 | — | — |
| 2.13 | 22Cr-5Ni-3Mo-N | 2-2.13 | — | — | A240 Gr. S32205 |
| 2.13 | 25Cr-5Ni-3Mo-2Cu | 2-2.13 | — | — | A240 Gr. S32550 |
| 2.13 | 25Cr-7Ni-4Mo-N | 2-2.13 | A182 Gr. F53 | — | A240 Gr. S32750 |
| 2.13 | 24Cr-10Ni-4Mo-V | 2-2.13 | — | A995 Gr. CE8MN (2A) | — |
| 2.13 | 25Cr-5Ni-2Mo-3Cu-N | 2-2.13 | — | A995 Gr. CD4MCuN (1B) | — |
| 2.13 | 25Cr-7Ni-3.5Mo-W-Cb | 2-2.13 | — | A995 Gr. CD3MWCuN (6A) | — |
| 2.13 | 25Cr-7Ni-3.5Mo-N-Cu-W | 2-2.13 | A182 Gr. F55 | — | A240 Gr. S32760 |
The group number is the standard's material-group index, not a ranking. Read the working pressure for the row from the pressure–temperature table named in the third column; the C-suffixed companion gives the same group in U.S. Customary units. "—" marks a product form for which the standard lists no specification.
Table 1.1-1 — Group 3 materials
Rows are listed in the order printed in Table 1.1-1, including the cases where a group spans several rows because it accepts several specifications for one product form.
B16.5 · ASME B16.5-2025
| Group | Nominal designation | P–T rating table | Forgings | Castings | Plates |
|---|---|---|---|---|---|
| 3.1 | 35Ni-35Fe-20Cr-Cb | 2-3.1 | A182 Gr. N08020 | — | A240 Gr. N08020 |
| 3.1 | 35Ni-35Fe-20Cr-Cb | 2-3.1 | B462 Gr. N08020 | — | B463 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. N02201 |
| 3.4 | 67Ni-30Cu | 2-3.4 | B564 Gr. N04400 | A494 Gr. M35-1 | B127 Gr. N04400 |
| 3.4 | 67Ni-30Cu | 2-3.4 | — | A494 Gr. M35-2 | — |
| 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 |
| 3.6 | 33Ni-42Fe-21Cr | 2-3.6 | B564 Gr. N08800 | — | B409 Gr. N08800 |
| 3.7 | 65Ni-28Mo-2Fe | 2-3.7 | B462 Gr. N10665 | — | B333 Gr. N10665 |
| 3.7 | 65Ni-28Mo-2Fe | 2-3.7 | B564 Gr. N10665 | — | — |
| 3.7 | 64Ni-29.5Mo-2Cr-2Fe-Mn-W | 2-3.7 | B462 Gr. N10675 | — | B333 Gr. N10675 |
| 3.7 | 64Ni-29.5Mo-2Cr-2Fe-Mn-W | 2-3.7 | B564 Gr. N10675 | — | — |
| 3.8 | 54Ni-16Mo-15Cr | 2-3.8 | B462 Gr. N10276 | — | B575 Gr. N10276 |
| 3.8 | 54Ni-16Mo-15Cr | 2-3.8 | B564 Gr. N10276 | — | — |
| 3.8 | 60Ni-22Cr-9Mo-3.5Cb | 2-3.8 | B564 Gr. N06625 | — | B443 Gr. N06625 |
| 3.8 | 62Ni-28Mo-5Fe | 2-3.8 | — | — | B333 Gr. N10001 |
| 3.8 | 70Ni-16Mo-7Cr-5Fe | 2-3.8 | — | — | B434 Gr. N10003 |
| 3.8 | 61Ni-16Mo-16Cr | 2-3.8 | — | — | B575 Gr. N06455 |
| 3.8 | 42Ni-21.5Cr-3Mo-2.3Cu | 2-3.8 | B564 Gr. N08825 | — | B424 Gr. N08825 |
| 3.8 | 55Ni-21Cr-13.5Mo | 2-3.8 | B462 Gr. N06022 | — | B575 Gr. N06022 |
| 3.8 | 55Ni-21Cr-13.5Mo | 2-3.8 | B564 Gr. N06022 | — | — |
| 3.8 | 55Ni-23Cr-16Mo-1.6Cu | 2-3.8 | B462 Gr. N06200 | — | B575 Gr. N06200 |
| 3.8 | 55Ni-23Cr-16Mo-1.6Cu | 2-3.8 | B564 Gr. N06200 | — | — |
| 3.9 | 47Ni-22Cr-9Mo-18Fe | 2-3.9 | B572 Gr. N06002 | — | B435 Gr. N06002 |
| 3.9 | 21Ni-30Fe-22Cr-18Co-3Mo-3W | 2-3.9 | B572 Gr. R30556 | — | B435 Gr. R30556 |
| 3.10 | 25Ni-47Fe-21Cr-5Mo | 2-3.10 | — | — | A240 Gr. N08700 |
| 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 |
| 3.12 | 47Ni-22Cr-20Fe-7Mo | 2-3.12 | — | — | B582 Gr. N06985 |
| 3.12 | 46Fe-24Ni-21Cr-6Mo-Cu-N | 2-3.12 | A182 Gr. N08367 | A351 Gr. CN3MN | A240 Gr. N08367 |
| 3.12 | 46Fe-24Ni-21Cr-6Mo-Cu-N | 2-3.12 | B462 Gr. N08367 | — | B688 Gr. N08367 |
| 3.12 | 46Fe-24Ni-21Cr-6Mo-Cu-N | 2-3.12 | B564 Gr. N08367 | — | — |
| 3.12 | 58Ni-33Cr-8Mo | 2-3.12 | B462 Gr. N06035 | — | B574 Gr. N06035 |
| 3.12 | 58Ni-33Cr-8Mo | 2-3.12 | B564 Gr. N06035 | — | B575 Gr. N06035 |
| 3.13 | 49Ni-25Cr-18Fe-6Mo | 2-3.13 | — | — | B582 Gr. N06975 |
| 3.13 | Ni-Fe-Cr-Mo-Cu-Low C | 2-3.13 | B564 Gr. N08031 | — | B625 Gr. N08031 |
| 3.13 | Ni-Fe-Cr-Mo-Cu-Low C | 2-3.13 | B462 Gr. N08031 | — | — |
| 3.14 | 47Ni-22Cr-19Fe-6Mo | 2-3.14 | — | — | B582 Gr. N06007 |
| 3.14 | 40Ni-29Cr-15Fe-5Mo | 2-3.14 | B462 Gr. N06030 | — | B582 Gr. N06030 |
| 3.14 | 58Ni-33Cr-8Mo | 2-3.14 | B564 Gr. N06035 | — | — |
| 3.15 | 42Ni-33Ni-21Cr | 2-3.15 | A182 Gr. N08810 | — | A240 Gr. N08810 |
| 3.15 | 42Ni-33Ni-21Cr | 2-3.15 | B564 Gr. N08810 | — | B409 Gr. N08810 |
| 3.15 | 62Ni-28Mo-5Fe | 2-3.15 | — | A494 Gr. N-12MW | — |
| 3.15 | 53Ni-17Mo-16Cr-6Fe-5W | 2-3.15 | — | A494 Gr. CW-12MW | — |
| 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 |
The group number is the standard's material-group index, not a ranking. Read the working pressure for the row from the pressure–temperature table named in the third column; the C-suffixed companion gives the same group in U.S. Customary units. "—" marks a product form for which the standard lists no specification.
Table 1.1-2 — bolting specifications and their notes
The bolting table is printed as four parallel lists: high strength, intermediate strength, low strength, and nickel and special alloy. The number in each category heading is the note that applies to the whole category; the number in the notes column adds a grade-specific rule. A dash means no extra note is printed for that entry, so only the category note applies.
B16.5 · ASME B16.5-2025
| Strength category | ASTM specification | Grade | Notes |
|---|---|---|---|
| High strength | A193 | B7 | — |
| High strength | A193 | B16 | — |
| High strength | A320 | L7 | (10) |
| High strength | A320 | L7A | (10) |
| High strength | A320 | L7B | (10) |
| High strength | A320 | L7C | (10) |
| High strength | A320 | L43 | (10) |
| High strength | A354 | BC | — |
| High strength | A354 | BD | — |
| High strength | A540 | B21 | — |
| High strength | A540 | B22 | — |
| High strength | A540 | B23 | — |
| High strength | A540 | B24 | — |
| Intermediate strength | A193 | B5 | — |
| Intermediate strength | A193 | B6 | — |
| Intermediate strength | A193 | B6X | — |
| Intermediate strength | A193 | B7M | — |
| Intermediate strength | A193 | B8 Cl. 2 | (11) |
| Intermediate strength | A193 | B8 Cl. 2B | (11) |
| Intermediate strength | A193 | B8C Cl. 2 | (11) |
| Intermediate strength | A193 | B8M Cl. 2 | (11) |
| Intermediate strength | A193 | B8M Cl. 2B | (11) |
| Intermediate strength | A193 | B8T Cl. 2 | (11) |
| Intermediate strength | A320 | L7M | (10) |
| Intermediate strength | A320 | B8 Cl. 2 | (11) |
| Intermediate strength | A320 | B8C Cl. 2 | (11) |
| Intermediate strength | A320 | B8F Cl. 2 | (11) |
| Intermediate strength | A320 | B8M Cl. 2 | (11) |
| Intermediate strength | A320 | B8T Cl. 2 | (11) |
| Intermediate strength | A449 | — | (12) |
| Intermediate strength | A453 | 651 | (13) |
| Intermediate strength | A453 | 660 | (13) |
| Low strength | A193 | B8 Cl. 1 | (6) |
| Low strength | A193 | B8C Cl. 1 | (6) |
| Low strength | A193 | B8M Cl. 1 | (6) |
| Low strength | A193 | B8T Cl. 1 | (6) |
| Low strength | A193 | B8A | (6) |
| Low strength | A193 | B8CA | — |
| Low strength | A193 | B8MA | — |
| Low strength | A193 | B8TA | (6) |
| Low strength | A307 | B | — |
| Low strength | A320 | B8 Cl. 1 | (6) |
| Low strength | A320 | B8C Cl. 1 | (6) |
| Low strength | A320 | B8M Cl. 1 | (6) |
| Low strength | A320 | B8T Cl. 1 | (6) |
| Nickel and special alloy | B164 | — | (7)–(9) |
| Nickel and special alloy | B166 | — | (7)–(9) |
| Nickel and special alloy | B335 | N10665 | (7) |
| Nickel and special alloy | B335 | N10675 | (7) |
| Nickel and special alloy | B408 | — | (7)–(9) |
| Nickel and special alloy | B473 | — | (7) |
| Nickel and special alloy | B511 | N08830 | (7) |
| Nickel and special alloy | B574 | — | (7) |
| Nickel and special alloy | B572 | N06230 | (7) |
| Nickel and special alloy | B637 | N07740 | (7) |
| Nickel and special alloy | B637 | N07718 | (7) |
- 1 Repair welding of bolting material is prohibited.
- 2 High-strength bolting: may be used with all listed flange materials and gaskets.
- 3 Intermediate-strength bolting: may be used with all listed materials and gaskets provided the user has verified that a sealed joint can be maintained under the rated working pressure and temperature.
- 4 Low-strength bolting: may be used with all listed materials but only in Class 150 and Class 300 joints (see para. 5.3.4 and Nonmandatory Appendix B for gasket recommendations).
- 5 Nickel and special alloy bolting: intended for use with comparable nickel and special alloy parts.
- 6 Austenitic stainless, carbide-solution-treated but not strain-hardened. Use ASTM A194 nuts of a compatible material.
- 7 Nuts may be machined from the same material or from a compatible grade of ASTM A194.
- 8 Maximum operating temperature is set at 260 °C (500 °F) unless the material is annealed, solution-annealed or hot-finished, because hard temper lowers design stress in the creep-rupture range.
- 9 Forging quality is not accepted unless the producer that last heats or works the parts tests them to the requirements of another permitted condition in the same specification and certifies final tensile, yield and elongation properties equal to or better than that condition.
- 10 Ferritic material intended for low-temperature service. Use ASTM A194 Gr. 4 or Gr. 7 nuts; with A320 L7M bolting use A194 Gr. 7M or 2HM nuts.
- 11 Austenitic stainless, carbide-solution-treated and strain-hardened. Use ASTM A194 nuts of a compatible material.
- 12 Nuts for quenched-and-tempered bolts: ASTM A194 Gr. 2 or Gr. 2H. Stud mechanical-property requirements are the same as for bolts.
- 13 Special alloy intended for high-temperature service with austenitic stainless steel.
Specification and grade as printed. Notes are paraphrased from the standard; the numbers in brackets are the note numbers printed against each entry. A dash marks an entry with no grade or no extra note as printed.
What the four bolting categories mean
- High strength (note 2): bolting with allowable stresses not less than those of ASTM A193 Grade B7. It may be used in any flanged joint (para. 5.3.2).
- Intermediate strength (note 3): the listed bolting and other bolting of comparable strength. It may be used in any flanged joint provided the user verifies the ability to seat the gasket and keep the joint sealed (para. 5.3.3).
- Low strength (note 4): bolting with a specified minimum yield strength of no more than 206 MPa (30 ksi). It is limited to Class 150 and Class 300 joints (para. 5.3.4) and calls for the gasket practice in para. 5.4.2 and Nonmandatory Appendix B.
- Nickel and special alloy (note 5): bolting for use with comparable nickel and special alloy components; the grade-specific notes (7), (8) and (9) on nuts, operating temperature and forging quality apply.
- General Note (a): bolting must not be used beyond the temperature limits of the governing code. General Note (b): ASME BPVC Section II bolting materials may be used where their requirements are identical to or more stringent than the ASTM specification.
- The strength categories are defined by strength, not by the ASTM designation alone; a grade is listed here because it falls into the category, and the notes decide where it may be used.
Table 1.1-3 — bolting dimensional recommendations
This table is a recommendation, not a dimensional requirement for the flange: it tells the purchaser and the manufacturer which bolt, stud, nut and thread standards go with carbon steel and alloy steel bolting. Section 6.10 refers to it for flange bolting dimensions, and para. 6.10.2 notes that the tabulated stud-bolt lengths in the dimension tables are reference dimensions, so other bolting lengths may be selected.
B16.5 · ASME B16.5-2025
| Product | Carbon steel | Alloy steel |
|---|---|---|
| Stud bolts | ASME B18.31.2 | ASME B18.31.2 |
| Bolts smaller than ¾ in. | ASME B18.2.1, square or heavy hex head | ASME B18.2.1, heavy hex head |
| Bolts equal to or larger than ¾ in. | ASME B18.2.1, square or heavy hex head | ASME B18.2.1, heavy hex head |
| Nuts smaller than ¾ in. | ASME B18.2.2, heavy hex | ASME B18.2.2, heavy hex |
| Nuts equal to or larger than ¾ in. | ASME B18.2.2, hex or heavy hex | ASME B18.2.2, heavy hex |
| External threads | ASME B1.1, Cl. 2A coarse series | ASME B1.1, Cl. 2A coarse series up through 1 in.; eight thread series for larger bolts |
| Internal threads | ASME B1.1, Cl. 2B coarse series | ASME B1.1, Cl. 2B coarse series up through 1 in.; eight thread series for larger bolts |
Reproduced as printed. The table distinguishes carbon steel from alloy steel bolting and gives a separate rule for threads above 1 in.
ASME B16.5 material groups — questions
Which pressure–temperature table applies to my flange material?
Look the material up in Table 1.1-1 and take the table number in the "pressure–temperature rating table" column. The same row also gives the accepted forging, casting and plate specifications, so the certificate and the rating table can be checked against one entry. The C-suffixed table is the U.S. Customary companion of the SI table.
Can plate material be used for any B16.5 flange?
No. Para. 5.1 and General Note (b) to Table 1.1-1 restrict plate and flat-bar materials to blind flanges and reducing flanges without hubs. Additional plate materials listed in ASME B16.34 may be used with the corresponding B16.34 Standard Class ratings.
Which bolting counts as high strength, and where can it be used?
High-strength bolting is the category whose allowable stresses are not less than those of ASTM A193 Grade B7; the listed entries are A193 B7 and B16, the A320 L7 series and L43, A354 BC and BD, and A540 B21 to B24. It may be used in any flanged joint. Intermediate strength adds the A193 and A320 austenitic grades, A320 L7M, A449 and A453 651/660, and requires the user to verify gasket seating and joint tightness; low strength is limited to Class 150 and Class 300. Check the category note before substituting.
What changed in the 2025 edition in these tables?
The 2025 edition revised Table 1.1-1 and Table 1.1-2. The bolting table gained ASTM A320 L7M (now listed under intermediate strength) and ASTM B511 (N08830), B572 (N06230) and B637 (N07740, N07718) under nickel and special alloy, and the table notes were revised and renumbered. Table 1.1-1 also carries the 2025 additions to the forging specifications and the new rating table for Material Group 2.13 duplex steels. Confirm any bolting or material certificate against the 2025 list rather than an older one.