This SAE Standard covers the mechanical and material requirements for three grades of steel nuts suitable for use in automotive and related engineering applications, in sizes 1/4 to 1-1/2 in, inclusive, and with dimensions conforming with the requirements of the latest issue of ASME B18.2.2 or ASME B18.6.3, as applicable.
| Nut Grade | C max | Mn min | P max | S max |
|---|---|---|---|---|
| 2 | 0.47 | ... | 0.12/2/ | 0.15*'! |
| 5 | 0.55 | 0.30 | o.os!4!! | 0.15(°!*5! |
| 8 | 0.55 | 0.30 | 0.04 | 0.05(^! |
NOTES :
1. All values are for ladle analysis (percent by weight) and are subject to standard varia- tions for check analysis as given in SAE J409.
2. Resulfurized and rephosphorized material is not subject to rejection based on check analysis for sulfur.
3. If agreed between purchaser and producer, sulfur content may be 0.23 max.
4. Phosphorus content may be 0.13 max for acid bessemer steel only.
5. If agreed between purchaser and producer, sulfur content may be 0.35 max and phos- phorus content may be 0.12 max provided that manganese content is 0.70 min.
6. If agreed between purchaser and producer, sulfur content may be 0.33 max provided that manganese content is 1.35 min.
| Nut Grade Nut Size Thread Series Nut Type |
2(4) 1/4 thru 1-1/2 UNC and BUN Proof Load Stress, psi (1) |
5 1/4 thru 1 UNC and SUN Proof Load Stress, psi (1) |
5 1/4 thru 1 UNF,12 UN and Finer Proof Load Stress, psi (1) |
5 Over 1 thru 1-1/2 UNC and SUN Proof Load Stress.psi (1) |
5 Over 1 thru 1-1'2 UNF,12UN and Finer Proof Lo-ad Stress, psi (1) |
8 1/4 thru 1-1J2 UNC and SUN Proof Load Stress, psi (1) |
8 1/4 thru 11-112 UNF,12UN and Finer Proof Load Stress, psi (1) |
|---|---|---|---|---|---|---|---|
| Hex | - | 120 000 | 109 000 | 105 000 | 94 000 | 150 000 | 150 000 |
| Hex Aange | - | 120 000 | 109 000 | 105 000 | 94 000 | 150 000 | 150 000 |
| Hex Jam (3) | - | 72 000 | 65 000 | 63 000 | 57 000 | 90 000 | 90 000 |
| Heavy Hex Jam (3) | - | 72 000 | 65 000 | 63 000 | 57 000 | 90 000 | 90 000 |
| Hex Slotted (3) | - | 96 000 | S7 000 | 84 000 | 75 000 | 120 000 | 120 000 |
| Heavy Hex (3) | - | 133 000 | 120 000 | 116 000 | 105 000 | 165 000 | 150 000 |
| Hex Thick (3) | - | 133 000 | 120 000 | 116 000 | 105 000 | 165 000 | 150 000 |
| Heavy Hex Slotted (3) | - | 105 000 | 96 000 | 92 000 | S4 000 | 132 000 | 120 000 |
| Hex Thick Slotted (3) | - | 105000 | 96000 | 92:000 | S4000 | 132000 | 12000-0 |
| Square (2) | 90 000 | - | - | - | - | - | - |
1.The proof load in pounds for a nut is computed by multiplying the proof load stress, in psi (Ibf/ink ), for the nut grade, size, thread series, and type, as shown in Table 2, and the stress area, in sq in (in'), for the applicable size and thread series shown in Table 3. (See Appendix A, Table A1 for computed values for some products.)
2.Grade 2 is normally applicable to square nuts only, and square nuts are normally available in Grade 2 only.
3.Proof load stress values for hex jam, heavy hex jam, hex slotted, heavy hex, hex thick, heavy hex slotted, and hex thick slotted nuts are based on requirements for hex nuts. Primarily, each value is derived from the ratio of minimum thickness of the product involved to the minimum thickness of hex or square machine screw nuts and hex nuts (see ASME B18.2.2 and ASME B18.6.3) of the same size—and adjusted to compensate for differences in width across flats, width and depth of slots, and depth of countersink.
| Coarse Thread Serles | Coarse Thread Serles | Fine Thread Serie.a | Fine Thread Serles | S-Thread Series |
8-Thf1'ad Series |
|---|---|---|---|---|---|
| UNC | UNC | UNF | UNF | 8 UN | 8 UN |
| Nominal Size and Threads Per Inch | Tensile Stress Area ,sq in | Nominal Size and Threads Per Inch | Tensile Stress Area ,sq ln | Nominal Size and Threads Per Inch | Tensile Stress Area sq in |
| 1/4 -20 | 0.0318 | 1/4 -28 | 0.0364 | - | - |
| 5/16 -18 | 0.0524 | 5/16-24 | 0.0580 | - | - |
| 318 -16 | 0.0775 | 318 -24 | 0.0878 | - | - |
| 7116 -14 | 0.1063 | 7/16- 20 | 0.1187 | - | - |
| 112 -13 | 0.1419 | 1/2 -20 | 0.1599 | - | - |
| 9/16 -12 | 0.182 | 9/16- 18 | 0.203 | - | - |
| 5/8-11 | 0.226 | 518 -18 | 0.256 | - | - |
| 314 -10 | 0.334 | 3/4 -16 | 0.373 | - | - |
| 7/6 - 9 | 0.462 | 7/8- 14 | 0.509 | - | - |
| 1-8 | 0.606 | 1-12 | 0.663 | 1 - 8 | 0.606 |
| 1-1/8- 7 | 0.763 | 1-1/8-12 | 0.856 | 1-1/8 -8 | 0.790 |
| 1-1/4 -7 | 0.969 | 1-1/4 -12 | 1.073 | 1-1/4 -8 | 1.000 |
| 1-318-6 | 1.155 | 1-3/S - 12 | 1.315 | 1-31S -8 | 1.233 |
| 1-112-6 | 1.405 | 1-112-12 | 1.581 | 1-1/2 -8 | 1.492 |