DDW

The hydraulic torque-angle-controlled tightening method indirectly measures the elongation of the bolt. With the thread pitch, a precise rotation angle can be linked to a defined change of length of the bolted joint. Both the compression strain within the clamped parts and the elastic and plastic deformations occurring in the interfaces until full contact are measured. However, this measurement can only be used for defining the preload if the rotation angle is actually transferred into a change of length of the bolted joint. Therefore, it must be ensured that all interfaces are perfectly superimposed with a defined rotation angle starting torque prior to angle measurement, and that the components to be tensioned can withstand the required surface pressure. Precise calculations are critical here. The hydraulic torque-angle-controlled tightening method developed by HYTORC not only monitors the rotation angle starting torque and the rotation angle, but also the final torque. The system does not approve the tightening process as correctly terminated until the required rotation angle and the final torque are within the required parameter range. Accuracy can be increased even further when the bolted joint is tightened to the superelastic range. During the tightening process, all process parameters are controlled, documented and archived by the Eco2TOUCH control. This tightening method is especially suitable for bolted joints with short grip lengths and in production processes/production lines. It may only be used when bolted joints in accordance with ISO 4014, ISO 4017 and ISO 4762 in threaded holes (blind holes) are assembled. Furthermore, suitable lubricants are to be used to prevent seizure or fretting.