Autofrettage in pressure sensors ensures zero-point stability

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 process is applied, to experience maximum stability, in particular 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 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. This selective influence on the structural conditions by means of autofrettage is an integral part of the development of the sensor and of the associated manufacturing process. Which pressure gauge octa is put through and how often, should 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 concluded that every sensor will automatically reap the benefits of 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 through the production stages. Ill-considered ? pressure gauge 10 bar ? 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 caused by 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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