... steel, 2High-speed steel, High-carbon steel 1.silicon carbide fiber disc, has good flexibility, high Intensity ... ,rose-red Sharp cutting, good edges holdout, durableSuitable for form grinding, knives, Measuring instrumentGreen silicon carbideGCgreenOnly no harder ... Optical glass, vitrify and other hard friable materials.Black silicon carbideCblack Harder than corundum, crisper, less flexibility.Suitable ...