INFLUENCE OF TEMPERATURE ON THE RESISTANCE TO FATIGUE BY BRAKING ON WIRES OF ALLOY CONDUCTORS 6201-T81 AND THERMORESISTANT ALUMINUM.
Fatigue; Fretting; Cable Conductors; Wire; Aluminum Alloy; high temperatures
This work aimed to study the effect of temperature on fretting fatigue tests on aluminum alloy wires (6201-T81) and heat-resistant aluminum wires from overhead conductors. A previous study (GARCIA, 2019) presented a device to successfully test yarn under fretting fatigue condition at room temperature. To provide real temperature conditions, controlled heating equipment was developed and installed on the existing device. The equipment was developed based on the classical proportional integral derivative (PID) temperature control. Thus, the development of the controlled heating equipment and the assembly of the device were presented with the methodology to perform the tests at high temperature. Fatigue tests under fretting conditions were performed on 6201-T81 aluminum wires and TAL alloy wires at room temperature, 75°C and 150°C with a normal load of 500 N. The wires subjected to the fretting fatigue test were examined with a scanning electron microscope (SEM). Fault surface evaluations showed failure characteristics due to fretting fatigue. The wire-to-wire contact marks generated by the device present, in the fracture region, all the characteristics found in the inner layers of the conductor cables of fractured transmission lines in use by fatigue in fretting conditions, such as a clearly defined adhesion zone and zones of partial slippage and presence of aluminum oxide, where the partial slip regime prevailed.