Effect of casting mould on grain size and mechanical properties of X120Mn12 steel

This study investigated the effects of grain size variations on the microstructure and mechanical properties of austenitic manganese steels (X120Mn12), which were cast in sand and permanent moulds. The effects of the mould type on the grain size of the alloys cast without heat treatment were determined. While the permanent mould alloy was cooled in open air after casting, the sand castings were cooled in the mould. In addition to measuring the grain size, OM (Optical Microscopy), XRD (X-Ray Diffraction), XRF (X-Ray Fluorescence), SEM, EDX (Energy-Dispersive X-Ray Spectroscopy), hardness, tensile, and impact tests were performed on the produced alloys. The permanent mould had a higher cooling rate, and therefore, the samples cast in it had a more refined grain structure. Thus, we could obtain a grain structure that was likely to exhibit the desired properties. Permanent mould casting resulted in 4.46% lower hardness, 46.15% higher tensile strength, 12.30% higher yield, and 52.84% lower elongation than sand casting. The notch impact test value was 1.18% higher, while the surface roughness (Ra) was 8.98% lower in the sand mould samples than in the permanent mould samples. The sand mould samples wore 53.48% more in the abrasive wear test.