The effect of the chemical composition of two low-carbon steels, C18E and 22MnB5, on their behavior after forming by fine blanking was investigated. A specific tool, adaptable to a tensile testing machine, was designed to replicate an industrial half-cutting process. This tool allows for the production of samples with simple geometries and easy modification of the processing conditions. Residual elements in the raw material, concentrated in segregation bands, appear to play a key role in crack initiation within the shear zone during the blanking process. The role of non-metallic inclusions is discussed to explain the presence of large cracks in C18E, while 22MnB5 only shows damage nucleation. After fine blanking, a carbonitriding heat treatment process was performed to modify the initial microstructure and achieve the required mechanical properties in the final parts. Continuous cooling transformation diagrams were created for both steels to guide this process. The results of this study demonstrate the better formability of 22MnB5 by fine blanking, compared to that of C18E.

The damage evolution of Ni-Cu-Mo conventionally sintered (CS) steels was investigated and compared to the damage resistance of a fully dense equivalent model material obtained by spark plasma sintering (SPS). The complex microstructure of the CS material—comprising martensite, bainite, and nickel-rich austenitic areas—was successfully reproduced via SPS followed by an additional post-sintering heat treatment. A residual porosity of less than 1% was achieved with SPS, compared to 8–14% with conventional sintering. Consequently, the steel produced by SPS exhibited higher ductility and tensile strength than the CS samples. CS and SPS samples both displayed a sharp decrease in Young’s modulus with strain, even at the onset of loading, indicating early damage nucleation and growth. A quantitative analysis of the porosity in fractured CS samples revealed no significant evolution in the pore dimensions and number. Concerning the SPS samples, the number and volume fraction of porosities were significantly higher in the fractured specimens compared to pristine ones. Two damage models derived from the continuum damage mechanics, one purely elastic, the other fully plastic, were compared with experimental data. It is shown that the elastic damage model could be successfully applied to the CS material, whereas, for the SPS process route, the steel underwent plastic straining assisted by plastic damage mechanisms.