It is known to optimize steel or stainless steel tubes for use with respect to service life and other characteristics, which can change disadvantageously over time and temperature, through autofrettage. It is further known that steel can be hardened, and that, for example, surface and edge layers can be hardened within limits in a targeted manner through a wide variety of methods, such as by influencing the temperature. For this purpose, the material is brought to certain temperatures, for example in furnaces or by means of electrical induction, and then further processed. Moreover, special corrosion-resistant steels or stainless steels are described for special applications which cannot be hardened by the means described above.
The application of additional layers is also known in order to protect steel from certain influences, such as the application of paint in especially corrosive environments. Such problems also arise particularly for tubes in an industrial setting or in measuring elements such as manometers, for example.
USPTO Backgrounds
USPTO Backgrounds