Autofrettage in pressure sensors ensures zero-point stability

In the manufacturing operation of pressure sensors, autofrettage denotes the procedure of active ?overload? by subjecting Weird 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 Definitive 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 areas of the sensor, in which through 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 means of autofrettage can be an integral area of the development of the sensor and of the associated manufacturing process. Which pressure the sensor is put through 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 should not be figured every sensor will automatically benefit from subjecting it to autofrettage. Autofrettage can only be utilized for ductile materials, but under no circumstances for brittle ones. Conditioning should be scheduled and carried out very selectively and with 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 additionally 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, by hit or miss.

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