ABSTRACT
The paper describes the applicable heat resistant steels for pressure vessels, working on high temperature. Such a high temperature apparatus is, for example, an ammonia synthesizer. The wall thicknesses of a converter are planned to be determined with three different internal pressures and temperature values. The investigated heat-resistant steels are classified in three groups: ferritic, austenitic and duplex (ferrite + austenite). There is a great variety of heat resistant steels in material properties, heat resistance, weldability and price. For the curve fitting calculations, the Table Curve program was used.
