← Glossary
Primary carbon
Primary carbon is carbon that crystallizes directly from the melt in cast iron as graphite or primary cementite. It influences the solidification behavior and castability.
Physical-Chemical Mechanism of Action
Primary carbon forms in the melt as graphite (hexagonal carbon) or primary cementite (carbon in amorphous state). This occurs during fast cooling and with low carbon contents.
Metallurgical Relevance & Welding Risks
Too high primary carbon can lead to hot cracking because the steel becomes glass-hard. It also affects castability and solidification behavior of cast iron.
Workshop Practice & Action Guidelines
To control primary carbon, the melting process must be precisely managed. If the carbon content is too high, the pouring time can be extended or cooling adjusted to encourage graphite formation.
MetallurgieSchweißtechnik