High-performance steels for pressure vessels

As consumption of energy in the world is rising, there is growing interest in the building of pressure vessels as well as apparatus engineering and equipment construction for the storage of gases or technical liquids. For these applications, like boilers, reactors and columns, unalloyed or Nb-microalloyed steels with a minimum yield strength of up to 460 MPa have been used and produced as heavy plates according to rules and international standards and specifications (i.e. DIN EN 10028, ASTM, ASME).
The production and properties of modern steels for welded pressure vessels, which meet the actual requirements very well, are discussed here. In this respect, thanks to specific secondary metallurgy during steelmaking, targeted Nb-microalloying, innovative rolling strategies and (if necessary) optimized heat treatment conditions, it is possible to produce a fine-grained microstructure in order to cover the highest material property requirements, in particular toughness and resistance to brittle failure. Multiple certifications of different steel grades according to different specifications for plates made from pressure vessel steels are common practice. Additionally, important aspects regarding the processing behaviour of modern steels for pressure vessels are stress-relief heat treatment and welding. Here, modern pressure vessel steels meet the highest demands for a practice-oriented processing of plates.