Autofrettage in pressure sensors ensures zero-point stability

In the manufacturing operation of pressure sensors, autofrettage denotes the procedure of active ?overload? by subjecting the pressure sensor selectively once or many 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 many years 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, where during 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 section 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 each sensor design by means of a complicated FEM simulation and extensive test series.
Caution ? no experiments of your own! However, it should not be figured every sensor will automatically benefit from subjecting it to autofrettage. Autofrettage can only just be utilized for ductile materials, but under no circumstances for brittle ones. Conditioning must be scheduled and completed very selectively sufficient reason for great care through the production stages. Ill-considered ?overpressurising? of Belong by laymen who like experimenting can 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 way, a noticable difference in instrumentation will only be achieved, if at all, by hit or miss.

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