What condition does graphitization cause in boiler steel?

Graphitization is a process that occurs in certain types of steel when exposed to high temperatures over time, particularly in environments with high carbon content. In the context of boiler steel, graphitization leads to the transformation of cementite (iron carbide) into graphite. This change diminishes the material's overall mechanical properties, primarily its strength. As the harder cementite is converted into softer graphite, the steel loses its ability to withstand stress and pressure, resulting in increased brittleness.

The weakening of the structure is particularly concerning in boiler applications because steel needs to maintain its integrity to handle the rigorous thermal and pressure conditions. Therefore, the condition that graphitization causes in boiler steel is a significant reduction in strength, leading to potential failure or cracking under operational stresses.