In the manufacturing operation of pressure sensors, autofrettage denotes the process of active ?overload? by subjecting the pressure sensor selectively once or several times to a pressure above the nominal pressure range. This technique is applied, to experience maximum stability, in particular 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 areas of the sensor, in which during the selective overload the yield point of the sensor material is locally exceeded, become plasticised, producing a permanent change of the instrumentation characteristics. This selective effect on the structural conditions by way of autofrettage is an integral portion of the development of the sensor and of the associated manufacturing process. Which pressure the sensor is put through and how often, should be determined individually for every sensor design through an elaborate FEM simulation and extensive test series.
Caution ? no experiments of your! However, it should not be figured every sensor will automatically reap the benefits of subjecting it to autofrettage. Autofrettage can only just be utilized for ductile materials, but for no reason for brittle ones. Conditioning should 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 can not only damage the sensor permanently, but also result in dangerous preliminary damage and subsequently possibly in accidents due to fatigue and bursting of the sensor. In Discount , a noticable difference in instrumentation is only going to be achieved, if at all, by hit or miss.