Chromium
Chromium forms a dense oxide layer in steels that prevents corrosion and increases hardness. It also improves weldability and resistance to chemical attack.
Physical-Chemical Mechanism of Action
Chromium reacts with oxygen in the air to form a dense, stabilized oxide layer. This layer protects the metal from further corrosion and prevents further reactions from occurring.
Metallurgical Relevance & Risks in Welding
Chromium significantly improves the corrosion resistance of steels. It reduces the occurrence of cracks and increases the strength of the weld. However, too much chromium (over 12%) can lead to increased hardness, which can make welding more difficult and increase susceptibility to hot cracking.
Workshop Practice & Action Guidelines
Use chromium in steels with caution to achieve an optimal balance between corrosion resistance and weldability. For high-chromium alloys (e.g., austenitic), ensure proper cooling to stabilize the microstructure. Avoid excessive hardness by controlling the chromium content.