ISO 898-1: Technical requirements for mechanical properties of bolts, screws, and studs
The international standard ISO 898-1 regulates the physical and mechanical parameters of fasteners made of carbon and alloy steels. The document covers bolts, screws, and studs with metric threads (coarse and fine pitch) tested within a temperature range of 10 °C to 35 °C. It is important to note that when operating in extreme temperature conditions, the stated performance characteristics may change.
Size ranges:
- Fine pitch: from M8x1 to M39x3.
- Coarse pitch: from M1.6 to M39.
Property classes according to ISO 898-1: 4.6, 4.8, 5.6, 5.8, 6.8, 8.8, 9.8, 10.9, 12.9.
EV Group China notes that this standard does not apply to set screws and other elements not subject to tensile loads (these parts are regulated by ISO 898-5). The specification does not cover requirements for fatigue resistance, stress corrosion cracking, weldability, or tightening friction coefficients.
Certain types of fasteners, such as those with countersunk or low heads, may exhibit deviations from standard tensile or torsional test requirements due to design features of the head geometry that reduce the shear area.
ISO 898-2: Mechanical properties of nuts made of carbon and alloy steel
The ISO 898-2 standard classifies nuts by type based on their height and functional purpose. EV Group China offers high-strength fasteners that meet strict engineering requirements:
| Nut type | Description | Height range (m min) |
|---|---|---|
| Type 1 | Standard hexagon nut | 0.80D ≤ m min < 0.89D |
| Type 2 | High nut | m min ≥ 0.89D |
| Type 0 | Thin nut | 0.45D ≤ m min < 0.80D |
For specialized products (prevailing torque nuts, flanged connections, or non-standard nut shapes), parameters are determined individually in the relevant specifications. When designing non-standard fasteners, calculations are based on the m(th, design) parameter — the minimum thread height relative to the nominal diameter D.