Mechanism of Grinding Surface Integrity Effects on Wear Resistance of Gray Cast Iron Materials

HT250 grey cast iron is a material of significance in the manufacture of precision machine tool guideways. The performance of guideways is significantly affected by the wear resistance of the machined surface. The present paper studies comparative grinding experiments conducted on HT250 using CBN and SiC wheels. The aim was to investigate the potential benefits of CBN grinding in enhancing surface wear resistance and to illuminate the underlying mechanisms. The results of these experiments demonstrate that, compared with SiC grinding, CBN grinding produces guideway specimens’ subsurface layer with finer grains (refined by approximately 15%) and notably higher microhardness (peak value of 382 HV). These microstructural improvements directly enhance the wear resistance of the ground surface. Within the tested parameter range, the optimal wear-resistant surfaces were obtained at a grinding speed of v_s = 30 m/s, a feed rate of v_f = 2000 mm/min, and a depth of cut of a_p = 6 μm. Under these conditions, surface roughness is better than R_a 0.4 μm, and surface microhardness achieves its maximum value. The wear tests were conducted using a ball-on-disk configuration under room temperature, oil lubrication, and applied loads ranging from 20 N to 80 N. The results show that, under the same loading and wear testing conditions, the wear depth of specimens machined with CBN wheels is reduced to 80–50% of that of specimens processed with conventional SiC wheels.