Materials and welding metallurgy

Creep-resistant and heat-resistant steels

This module distinguishes two frequently confused groups: steels resistant to oxidation at high temperature and steels intended for long-term loading under creep conditions. For welding, the material standard, EN ISO 15608 group, creep/oxidation behaviour, preheat, PWHT and compatible filler material are decisive.

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Topic overview

This module distinguishes two frequently confused groups: steels resistant to oxidation at high temperature and steels intended for long-term loading under creep conditions. For welding, the material standard, EN ISO 15608 group, creep/oxidation behaviour, preheat, PWHT and compatible filler material are decisive.

The priority is chemical resistance of the surface at high temperature: oxidation, scaling, sulfidation and carburisation. Typical grades contain higher chromium, often silicon/aluminium, and nickel in austenitic types.

The priority is strength under long-term loading at elevated temperature: creep, relaxation and precipitate stability. Typical materials include Cr-Mo, Cr-Mo-V and 9–12 % Cr steels, as well as some nickel- or cobalt-base alloys.

The basis of heat resistance. It forms a protective Cr₂O₃ layer, improves oxidation resistance and, in CrMo steels, also contributes to creep strength.

What the module covers

  • Heat-resistant and creep-resistant steels
  • 1. Standards and typical applications
  • 2. Elements that improve high-temperature properties
  • 3. Typical steel groups
  • 4. Procedure for the welding engineer before welding
  • Essential requirements
  • Why it is critical
  • Most common mistake
Educational content does not replace current standards, approved WPS/WPQR documentation or decisions by competent welding coordination personnel.