Eutectic Ledeburite Rim
The eutectic ledeburite border is a fine, cellular mixture of austenite and cementite during solidification of cast iron. It forms a hard carbide network and limits the plastic deformability of the structure.
Physical-Chemical Mechanism of Action
During cooling of cast iron, the eutectic ledeburite border forms by simultaneous solidification of austenite and cementite. This process creates a fine, cellular structure with a hard carbide network.
Metallurgical Relevance & Welding Risks
The eutectic ledeburite border limits the plastic deformability of the steel and can lead to cracks if the material is not welded correctly. Too fast cooling can coarsen the border and increase hardness, leading to hot cracks.
Workshop Practice & Action Guidelines
To minimize the risk of cracks and hot cracks, controlled cooling should be ensured during welding. The cooling time should be between 5 and 20 seconds to achieve a balanced structure. If necessary, use a cooling rod or cooling unit to regulate the temperature in the border.