BS 7814:1995

This British Standard specifies the materials, mechanical properties and marking requirements for bolts and screws incorporating either underhead locking or anti-rotation features when tested at an ambient temperature between 15 °C and 30 °C.

It applies to bolts and screws:

1. with ISO metric M2 to M20 threads conforming to BS 3643-2:1981;
2. with mechanical properties 80, 90 or 100¹⁾ as appropriate;
3. for use within the temperature range – 50 °C to + 250 °C.

As the decarburization of any underhead locking or anti-rotation feature will seriously impair its intended function, partial or complete decarburization as given in BS EN 20898-1:1992 does not apply to this standard. There is instead a requirement for carbon restoration to ensure that no decarburization of the locking or anti-rotation feature takes place during the heat treatment process.

NOTE Performance at temperatures outside the operating range is not within the requirements of this standard.