SPECIFICATION FOR STEEL RIVETS AND BARS FOR RIVETS, PRESSURE VESSELS
(Identical with ASTM Specification A31-XX, where XX represents the latest issue year.)
1. Scope
1.1 This specification covers steel rivets for use in boilers and pressure vessels and steel bars for use in the manufacture of rivets.
1.2 Two grades are covered:
- 1.2.1 Grade A — Bars having a yield point of 23 000 psi (160 MPa) minimum with no controls on carbon content.
- 1.2.2 Grade B — Bars having a yield point of 29 000 psi (200 MPa) minimum with carbon 0.28% maximum.
- 1.2.3 Rivets are manufactured from the applicable bar grade.
1.3 The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are for information only.
2. Referenced Documents
2.1 ASTM Standards:
- A29/A29M Specification for Steel Bars, Carbon and Alloy, Hot-Wrought, General Requirements for
- A370 Test Methods and Definitions for Mechanical Testing of Steel Products
- A751 Test Methods, Practices, and Terminology for Chemical Analysis of Steel Products
- F1470 Guide for Fastener Sampling for Specified Mechanical Properties and Performance Inspection
2.2 ASME Standards:
- B18.1.1 Small Solid Rivets 6 Inch Nominal Diameter and Smaller
- B18.1.2 Large Rivets 6 Inch Nominal Diameter and Larger
- B18.24 Part Identifying Number (PIN) Code System Standard for B18 Fastener Products
3. Ordering Information
3.1 Orders for rivets and bars under this specification shall include:
- 3.1.1 Specification designation and date of issue,
- 3.1.2 Quantity — Number of pieces for rivets and weight for bars,
- 3.1.3 Name of product and grade (A or B),
- 3.1.4 Size (diameter and length),
- 3.1.5 Rivet head type,
- 3.1.6 If inspection at point of manufacture is required,
- 3.1.7 DELETED
- 3.1.8 Additional testing or special requirements, if required,
- 3.1.9 For establishment of a part identifying system, see ASME B18.24.
NOTE 1 — A typical ordering description is: ASME SA-31, 2015 edition, 10 000 pieces, steel rivets Grade A, button head.
4. Materials and Manufacture
4.1 The steel shall be made by any of the following processes: open-hearth, electric-furnace, or basic-oxygen.
4.2 Rivets shall be manufactured from rivet bars conforming to the applicable grade ordered.
4.3 Rivets shall be manufactured by hot- or cold-heading.
4.4 Bars shall be furnished as rolled and not pickled, blast cleaned, or oiled. At producer's option, bars may be cleaned for inspection or cold drawn.
5. Chemical Composition
5.1 The steel shall conform to chemical composition prescribed in Table 1.
| Element | Grade A | Grade B | ||
|---|---|---|---|---|
| Heat Analysis | Product Analysis | Heat Analysis | Product Analysis | |
| Carbon, max., % | — | — | 0.28 | 0.31 |
| Manganese, % | 0.30-0.60 | 0.27-0.63 | 0.30-0.80 | 0.27-0.83 |
| Phosphorus, max., % | 0.040 | 0.048 | 0.040 | 0.048 |
| Sulfur, max., % | 0.050 | 0.058 | 0.050 | 0.058 |
5.2 Heat Analysis — An analysis of each heat of steel shall be made by the bar manufacturer to determine for Grades A and B the percentages of carbon, manganese, phosphorus, and sulfur. This analysis shall be made from a test ingot taken during the pouring of the heat. The chemical composition thus determined shall be reported to the purchaser or his representative and shall conform to the requirements for heat analysis in accordance with Table 1.
5.3 Product Analysis — An analysis may be made by the purchaser from finished materials representing each heat. The chemical composition thus determined shall conform to the requirements for product analysis prescribed in Table 1.
5.4 Application of heats of steel to which bismuth, selenium, tellurium, or lead has been intentionally added shall not be permitted.
5.5 Chemical analyses shall be performed in accordance with Test Methods, Practices, and Terminology A751.
6. Mechanical Properties
6.1 Rivet Bend Tests:
6.1.1 The rivet shank of Grade A steel shall stand being bent cold through 180° flat on itself, as shown in Fig. 1, without cracking on the outside of the bent portion.
6.1.2 The rivet shank of Grade B steel shall stand being bent cold through 180° without cracking on the outside of the bent portion in accordance with Table 2.
| Diameter of Rivet Shank, in. | Ratio of Bend Diameter to Diameter of Rivet Shank | |
|---|---|---|
| Grade A | Grade B | |
| ¾ and under | flat | 1 |
| Over ¾ | flat | 1½ |
6.2 Rivet Flattening Tests
6.2.1 The rivet head shall stand being flattened, while hot, to a diameter 2½ times the diameter of the shank, as shown in Fig. 2, without cracking at the edges.
6.3 Bar Tensile Properties
6.3.1 Bars shall conform to the tensile requirements in accordance with Table 3.
| Property | Grade A | Grade B |
|---|---|---|
| Tensile strength, psi (MPa) | 45 000-55 000 (310-380) | 58 000-68 000 (400-470) |
| Yield point, min., psi (MPa) | 23 000 (160) | 29 000 (200) |
| Elongation in 8 in. or 200 mm, min., % | 27 | 22 |
| Elongation in 2 in. or 50 mm, min., % | 33 | 25 |
6.4 Bar Bend Tests:
6.4.1 The test specimen for Grade A steel bars shall stand being bent cold through 180° flat on itself without cracking on the outside of the bent portion.
6.4.2 The test specimen for Grade B steel bars shall stand being bent cold through 180° without cracking on the outside of the bent portion to an inside diameter which shall have a relation to the diameter of the specimen in accordance with Table 4.
| Specimen Diameter, in. | Ratio of Bend Diameter to Diameter of Specimen | |
|---|---|---|
| Grade A | Grade B | |
| ¾ and under | flat | — |
| Over ¾ | flat | 1 |
7. Dimensions, Mass, and Permissible Variations
7.1 Rivets:
7.1.1 The dimensions of rivets shall conform to B18.1.2 for nominal diameters 6 in. and larger and B18.1.1 for nominal diameters 6 in. and less.
7.1.2 Snap gage measurement shall be made at the point of minimum diameter, but it is not required that the rivet shall turn completely in the gage. Measurements of the maximum tolerance shall be made with a ring gage, all rivets to slip full to the head in the gage of the required size for the various diameters.
7.2 Bars
7.2.1 The diameter of hot-finished rivet bars shall not vary from the size specified by more than the amounts in accordance with Table 5.
| Specified Size, in. | Variations from Size, in. | Out-of-RoundA, in. | |
|---|---|---|---|
| Over | Under | ||
| ¾ and under | 0.005 | 0.005 | 0.008 |
| Over ¾ to 7/16, incl | 0.006 | 0.006 | 0.009 |
| Over 7/16 to 5/8, incl | 0.007 | 0.007 | 0.010 |
| Over 5/8 to 7/8, incl | 0.008 | 0.008 | 0.012 |
| Over 7/8 to 1, incl | 0.009 | 0.009 | 0.013 |
| Over 1 to 1⅛, incl | 0.010 | 0.010 | 0.015 |
| Over 1⅛ to 1¼, incl | 0.011 | 0.011 | 0.016 |
| Over 1¼ to 1⅜, incl | 0.012 | 0.012 | 0.018 |
| Over 1⅜ to 1½, incl | 0.014 | 0.014 | 0.021 |
| A Out-of-round is the difference between the maximum and minimum diameters of the bar, measured at the same cross-section. | |||
8. Workmanship, Finish, and Appearance
8.1 Rivets
8.1.1 The finished rivets shall be true to form, concentric, and free of injurious defects.
8.2 Bars:
8.2.1 Bars shall be free of visible pipe, undue segregation, and injurious surface imperfections.
8.2.2 Surface Finish — The bars shall have a commercial hot-wrought finish obtained by conventional hot rolling. See 4.4 for producer's descaling option.
9. Number of Tests and Retests
9.1 Rivets
9.1.1 Sampling for rivet bend and rivet flattening tests shall be in accordance with Guide F1470, detection process.
9.2 Bars:
9.2.1 Two tension tests shall be made from each heat, unless the finished material from a heat is less than 50 tons (45 Mg), when one tension test will be sufficient. However, for material 2 in. (51 mm) and under in thickness, when the material from one heat differs ¾ in. (9.5 mm) or more in thickness, one tension test shall be made from both the thickest and the thinnest material rolled regardless of the weight represented. Each test shall conform to the specified requirements.
9.2.2 Retests on bars may be made in accordance with Specification A29/A29M.
10. Specimen Preparation
10.1 Rivets
10.1.1 Rivets shall be tested in their full-size finished condition.
10.2 Bars:
10.2.1 Test specimen selection and preparation shall be in accordance with Specification A29/A29M and Test Methods and Definitions A370.
10.2.2 Tension and bend test specimens for rivet bars which have been cold drawn shall be normalized before testing.
11. Test Methods
11.1 Rivets
11.1.1 Rivet bend and flattening tests shall be in accordance with the manufacturers standard test procedures.
11.2 Bars
11.2.1 Tension and bend tests shall be conducted in accordance with Test Methods and Definitions A370, and especially Supplement I thereof, on steel bar products.
12. Inspection
12.1 If the testing described in Section 9 is required by the purchaser, it shall be specified in the inquiry and contract or order.
12.2 The inspector representing the purchaser shall have free entry at all times, while work on the contract of the purchaser is being performed, to all parts of the manufacturer's works that concern the manufacture of the material ordered. The manufacturer shall afford the inspector all reasonable facilities, without charge, to satisfy him that the material is being furnished in accordance with this specification. All tests (except product analysis) and inspection shall be made at the place of manufacture prior to shipment, unless otherwise specified, and shall be so conducted as not to interfere unnecessarily with the operation of the works.
13. Rejection and Rehearing
13.1 Rivets
13.1.1 Rivets that fail to conform to the requirements of this specification may be rejected. Rejection should be reported to the producer or supplier promptly and in writing. In case of dissatisfaction with the results of the test, the producer or supplier may make claim for a rehearing.
13.2 Bars
13.2.1 Rejection and rehearing shall be in accordance with Specification A29/A29M.
14. Certification
14.1 The manufacturer shall furnish certification that the material was manufactured and tested in accordance with this specification together with a report of the heat analysis (5.2) and mechanical property test results (Section 6) as applicable to the product ordered. The report shall include the manufacturer's name, ASTM designation, grade, heat number (bars only), and authorized signature.
15. Responsibility
15.1 The party responsible for the fastener shall be the organization that supplies the fastener to the purchaser.
16. Packaging and Package Marking
16.1 Rivets
16.1.1 Rivets shall be properly packed and marked to prevent damage and loss during shipment.
16.2 Bars
16.2.1 Bars shall be packed and marked in accordance with Specification A29/A29M.
17. Keywords
17.1 bars; carbon steel; pressure vessel rivets; rivets; steel
