Proof load
Material and thread type
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
- There is no proof load table in the source; the values are the effective sectional area multiplied by the proof stress. The effective sectional area is calculated as given in JIS B 1082. Where the source has the same table, the values have been checked against it. (the source has no table for stainless steel nuts).
- 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 1052-6, JIS B 1054-2, JIS B 0205-4, JIS B 1082