Deoxidizing agent
Deoxidizers are additives like silicon, aluminum, or manganese that bind oxygen and form slag. They prevent porosity and improve strength, but too high concentrations can embrittle the weld.
Physical-Chemical Mechanism of Action
Deoxidizers like silicon (Si), aluminum (Al), or manganese (Mn) have a strong affinity for oxygen. They react in the molten pool and bind oxygen into molecular slag that floats to the surface of the metal.
Metallurgical Relevance & Risks in Welding
Using deoxidizers prevents pore formation in the weld pool and improves weld strength. However, too high a content of deoxidizers (e.g., silicon above 0.40%) can cause the weld to become brittle. This increases susceptibility to hot cracking and reduces mechanical toughness.
Shop Practice & Action Instructions
When selecting deoxidizers, pay attention to the correct content relative to the metal being welded. For low-carbon steel (e.g., 0.1% C), a silicon content of up to 0.40% is suitable. For higher carbon content or special applications, the content may vary. Ensure deoxidizers are applied correctly and the weld pool is cleaned regularly.