Degradation of springs used in high-voltage breaker under the simulated operating conditions

As a key part of high-voltage breakers, spring actuators are widely used for their advantages of simple structure, rapid response, and no pollution. As the energy storage unit, the spring is prone to stress relaxation and fatigue fracture due to the complex manufacturing process, large working load, long serving time, and environmental impact. To address these issues, the degraded characteristics of the typical 60Si2CrVA alloy steel spring were studied in the simulated working conditions, and the influence of different temperature, humidity, and salt spray conditions on the performance of the spring was analyzed. The results show that temperature and salt spray corrosion are two of the main factors to affect the mechanical performance of the spring. As the temperature increases, the maximum stress loss rate of the spring increases quickly in the initial stage and then gradually keeps stable in the second stage. Under corrosive conditions, the springs are more likely to reach the stress relaxation rate threshold in a short time. For the life prediction of springs, the mathematical model was constructed by an adjusted Arrhenius equation to fit the experimental data, and calculate the numerical parameters of the spring under different environmental conditions. It is found that the service life of the spring is about 28.51 years when running at 30°C with a stress relaxation threshold of 6%.