Carbon Partitioning and Carbide Precipitation During Quenching and Partitioning Process of 12%Cr Martensitic Stainless Steel

Most research on Q&P heat treatments is limited to suppressed carbide precipitation models. This study investigates the carbon partitioning and carbide precipitation of Q&P stainless steel containing 12% chromium. According to the investigation conducted using field emission scanning electron microscopy (FESEM), precipitation of iron carbide was observed in the specimens partitioned at 450 degrees C. Analysis via X-ray diffraction (XRD) and energy-dispersive spectroscopy (EDS) confirmed that carbide precipitation occurred in the microstructure as partitioning temperature increased from 370 to 450 degrees C. The difference in hardness between samples partitioned at 370 and 450 degrees C was due to carbide precipitation during the partitioning of the sample at 450 degrees C and a more stable retained austenite (RA) at 370 degrees C. The RA percentage and austenite lattice parameter decreased as the partitioning temperature rose from 370 to 450 degrees C due to carbide precipitation, resulting in a reduction in carbon sources.