Copper (Cu)
Copper improves resistance to corrosion and atmospheric effects through its electrochemical protective ability and oxygen binding.
Physical-Chemical Mechanism of Action
Copper forms a thin, corrosion-resistant layer on the surface of the steel. This layer prevents direct contact between the steel and air or water, reducing corrosion. In addition, copper binds oxygen, which reduces the conditions that encourage corrosion.
Metallurgical Relevance & Welding Risks
Too high a copper content can alter the structure of the steel and impair its mechanical properties. Excess copper causes grain coarsening, which reduces toughness and hardness. It can also cause difficulties in welding because copper has poor conductivity for heat and electricity.
Shop Practice & Action Instructions
Ensure that the copper content in the steel is within the permissible range (typically between 0.1 and 0.5 %). When welding, use suitable protective measures and avoid overheated welds to prevent corrosion. Monitor the temperature and cooling of the steel to ensure proper structure development.