Resumen:
This standard specifies a method of determining the coefficient of friction in the thread when tightening bolts or nuts under specified conditions. It is only applicable for comparison purposes, such as a comparison of bolt/nut assemblies with different surface finishes or for cases where different lubricants are to be assessed. Application-oriented tightening tests relevant for determining the coefficient of friction in bolt/nut assemblies forming part of specific structural units are not covered in detail in this standard given the complexity of requirements involved. This standard is based on the assumption that there is a calculational linear relationship between torque, clamp force and coefficient of friction across the whole measuring range. With this standard, the influence of the clamping torque of the nut on the connection can be seen, especially at low torques, e. g. as they occur in shear connections with Hi-Loks and aluminium rings. For high-strength connections and high preload forces, however, the influence of the clamping torque on the connection is only very small or even negligible. Unless otherwise agreed, tests should be carried out at room temperature. However, tests under specified conditions are to be carried out in a temperature range from 18 °C to 27 °C. This standard is intended for aerospace applications only. For general technical applications, see DIN EN ISO 16047.
Keywords:
Aerospace transport, Air transport, Bolted joints, Bolts, Coefficient of friction, Conditions, Definitions, Designations, Dimensions, Fasteners, Friction torque, Initial stressing, k value, Mathematical calculations, Mechanical testing, Nuts, Ratings, Resilience, Screws (bolts), Studs (fasteners), Surface roughness, Symbols, Tensile strain, Tensile strength, Test performance, Testing, Threads, Tightening torque, Torque, Washers, Yield strength