High performance steels for pressure vessels

While consumption of energy in the world is rising there is growing interest in the building of pressure vessels as well in apparatus engineering and equipment construction for the storage of gases or technical liquids. For these applications, unalloyed or Nb-microalloyed steels with a minimum yield strength of up to 460MPa have been used and produced as heavy plates according to rules and standards and specifications (i.e. DIN EN 10028, ASTM, ASME). This paper discusses the production and properties of modern steels for welded pressure vessels, which fit the actual requirements very well. Due to purposeful Nb-microalloying, innovative rolling strategies and (if necessary) optimised heat treatment conditions are possible to produce a fine grained microstructure in order to cover the highest material property requirements, in particular the toughness and the resistance against brittle failure. Additionally, important aspects regarding the processing behaviour of modern steels for pressure vessels are highlighted. (AU) © TMS