In the manufacturing operation of pressure sensors, autofrettage denotes the procedure 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, specifically of the zero point, in later operation. Assuming a suitable design of the sensor, autofrettage enables a long time of trouble-free operation of the sensors even at high load cycles reaching the specified overload range, without leading to zero-point shift or similar effects.
In autofrettage, certain local regions of the sensor, where through the selective overload the yield point of the sensor material is locally exceeded, become plasticised, producing a permanent change of the instrumentation characteristics. pressure gauge 10 bar on the structural conditions by way of autofrettage is an integral the main 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 by means of an elaborate 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 used for ductile materials, but under no circumstances 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 additionally result in dangerous preliminary damage and subsequently possibly in accidents caused by fatigue and bursting of the sensor. In this manner, an improvement in instrumentation is only going to be achieved, if at all, by hit or miss.