Verification of lubricant friction coefficients
In our laboratory we have special equipment for verifying the coefficients of friction of lubricants and pastes used for lubrication of screw joints. We use the measured results in calculations of tightening torques.
- Equipment and measurement of coefficients of friction in the thread and under the head is performed in accordance with ČSN EN 16047.
- We develop our own lubricants for screw connections.
Example of friction coefficients measured in accordance with ČSN EN 16047The graphs show a steady course of friction in the thread and under the nut. The horizontal axis expresses the theoretical pressure in the thread p th, respectively under the nut p b, which increases during tightening. It is evident from the course of the curves that the friction does not change with increasing load.
Course of the coefficient of friction in the thread depending on the load
LF Booster - assembly paste for screwed joints
The course of the coefficient of friction under the nut depending on the load
Measured on bolts M33x3,5x300 according to ČSN 131520.2
Do you need the right tightening torque?
You can find the calculator at: utahovacimoment.tesneni.cz
1. Enter values
2. Design of optimal tightening torque
3. Display of the load level of the screw connection in the assembly state
The result is the tightening torque MU and the screw check for tensile stress σt [MPa], torque τk [MPa] and reduced stress for POWER ® torque LF kote 450.