The metallurgical mystery of silicon calcium alloy: why can it become a necessity for high-end manufacturing?
2026,01,14
In modern metallurgical industry, Silicon Calcium Alloy has become an indispensable key material for producing high-quality steel and cast iron. The reason why this alloy is so important is due to its unique chemical composition and excellent metallurgical properties.
The multiple affinities of calcium: its natural purifying ability
Due to the strong affinity between calcium and oxygen, sulfur, hydrogen, nitrogen, and carbon in molten steel, silicon calcium alloys are mainly used for deoxidation, degassing, and sulfur fixation in molten steel. This characteristic makes calcium a versatile tool in the purification process of molten steel:
Deoxygenation ability: Calcium can effectively remove dissolved oxygen from molten steel
Desulfurization effect: forming stable calcium sulfide and reducing sulfur content in steel
Degassing effect: Combining hydrogen, nitrogen and other gases to reduce steel defects
2. Dynamic metallurgical reactions: the entire process from addition to purification
The addition of silicon calcium to molten steel produces a strong exothermic effect. This exothermic reaction not only provides the heat required for metallurgical processes, but more importantly:
Calcium turns into calcium vapor in molten steel: Due to the boiling point of calcium (1484 ℃) being lower than the temperature of the steel, calcium rapidly vaporizes
Strong stirring effect: During the rising process of calcium vapor, it vigorously stirs the molten steel
Promote the upward movement of inclusions: This stirring effect is beneficial for the upward movement of non-metallic inclusions
3. Inclusion modification: transition from harmful to harmless
After deoxidation of silicon calcium alloy, non-metallic inclusions with larger particles that are easy to float are produced, and the shape and properties of non-metallic inclusions are also changed.
This process includes:
Transforming high melting point solid inclusions into low melting point liquid inclusions
Promote the aggregation of small particle inclusions into large particles
Change the shape of inclusions to make them more rounded and dispersed
