Proof load of steel nuts, coarse thread
Steel nuts (coarse thread)ISO 898-2 (JIS B 1052-2)Unlike bolts, the proof stress rises with nominal diameter within the same property class. Steel nuts (fine thread)ISO 898-6 (JIS B 1052-6)A separate standard from the coarse thread. At the same property class the stress is higher, and the range of nominal diameters is narrower.Stainless steel nuts (coarse thread)ISO 3506-2 (JIS B 1054-2)The proof stress does not change with the nominal diameter; it splits into two according to the nut height.Stainless steel nuts (fine thread)ISO 3506-2 (JIS B 1054-2)The proof stress is the same as for the coarse thread. The larger stress area makes the proof load larger by the same amount.
Notes
- The proof load is the effective sectional area multiplied by the proof stress. The effective sectional area is calculated as given in JIS B 1082. Checked against the table in the source (JIS B 1052-2:2014, Table 4).
- Unlike bolts, the proof stress rises with nominal diameter within the same property class. For property class 5 they are 580 / 590 / 610 / 630 N/mm2 — four steps.
- The table covers only the designations given in the source. Nominal diameters of 5 mm and above are covered; M3 and M4 are not in the source. A blank means that, for that size, that property class is not specified. Property class 9 is specified only up to 16 mm.
- The values here are for room temperature. Mechanical properties change at high and low temperatures, so do not apply these values directly.
- Sources: JIS B 1052-2, JIS B 0205-4, JIS B 1082