In the manufacturing operation of pressure sensors, autofrettage denotes the process of active ? Trade Secret ? by subjecting Belong or several times to a pressure above the nominal pressure range. This process is applied, to experience maximum stability, specifically of the zero point, in later operation. Assuming the right design of the sensor, autofrettage enables a long time of trouble-free operation of the sensors even at high load cycles achieving the specified overload range, without resulting in zero-point shift or similar effects.
In autofrettage, certain local regions of the sensor, in which through the selective overload the yield point of the sensor material is locally exceeded, become plasticised, resulting in a permanent change of the instrumentation characteristics. This selective effect on the structural conditions by way of autofrettage is an integral area of the development of the sensor and of the associated manufacturing process. Which pressure the sensor is subjected to and how often, must be determined individually for each sensor design through a complicated FEM simulation and extensive test series.
Caution ? no experiments of your own! However, it must not be figured every sensor will automatically benefit from subjecting it to autofrettage. Autofrettage can only just be utilized for ductile materials, but for no reason for brittle ones. Conditioning must be scheduled and completed very selectively sufficient reason for great care during the production stages. Ill-considered ?overpressurising? of pressure sensors by laymen who like experimenting will not only damage the sensor permanently, but also bring about dangerous preliminary damage and subsequently possibly in accidents due to fatigue and bursting of the sensor. In this manner, an improvement in instrumentation will only be achieved, if at all, by hit or miss.