SSH EN 14831:2005

Fasteners - Tightening performance - Torque/Angle simplified test method

Scope

This European standard specifies a test method for fasteners with ISO metric thread from M6 to M16 and with property classes 8.8 to 12.9 for bolts and screws and with property classes 8 to 12 for nuts, to check their tightening performance in the elastic range.
It applies to steel fasteners with an ISO metric thread according to ISO 68-1.
It applies to fasteners having a friction coefficient from 0,06 up to and including 0,18. For higher values of friction coefficients, the dispersion of test results increases and the test method should not be applied. For lower values friction of coefficients, which are for very specific applications and require special lubrication, this standard does not apply.
This comparative test method can be used to monitor stability of a production process (such as coating, lubrication, shot-blasting) or to compare various production manufacturing lots. It can also be used to detect fasteners, which are out of specification.
NOTE This simplified test method has been developed to avoid systematic use of more complex procedures.
In case of dispute the torque/tension test method according to EN ISO 16047 is the referee test.
This standard does not apply for assessment of fasteners in actual assembly conditions; it does not allow the measurement of operating friction coefficients.