Nitrogen-alloyed austenitic steels with extraordinary strength properties and outstanding corrosion resistance

摘要

Starting from austenitic standard steels with nitrogen addition, the possibilities to increase the strength levels of these steel grades are presented. The effect of nitrogen additions on the properties of these steels is described. Fullyaustenitic steels with 0.2% proof stress levels between 400 and 500 N/mm{sup}2 are described, the mechanical properties of these grades are shown at room temperature and at elevated temperatures.Compared with the stainless steels commonly used for the construction of chemical equipment, the strength levels of nitrogen-alloyed steels are clearly higher, whereas the benefits of austenite, for instance high toughness and favourable processingbehaviour, is retained. Corrosion tests reveal that these steels, in comparison to austenitic standard steels, exhibit a very good resistance both against pitting induced by chlorides and against various acids. The influence of nitrogen content on the"effective sum" is discussed in this context. Notes are given in respect to processing of these steels, particularly welding.