1. Typology

The main types of refractory steels and alloys can be classified according to their metallographic structure as follows.

• Martensitic or semi-ferritic steels

  • 5-10% Cr steels

    They generally have Si, Al, Mo and V additions. Strictly speaking, they are not stainless steels, but their use puts them in the category of refractory steels. In this category, we find 6% Cr steels, used for superheater tubes in thermal power plants (X8CrMoV6 steel), or to withstand hydrogen under pressure at high temperatures.

  • 9-10% Cr steels

    They are used for superheater tubes (X10CrMo9, X10CrMoVNb9).

  • 10-13% Cr steels

    They are...