Tungsten Carbide (sp.gr. 15)

Various alloys available (low carbon, high carbon, chrome steel, stainless steel, etc.) in a variety of forms:

Ball bearings Good wear, very round but will result in metallic contamination. Cost directly related to material and inversely proportional to size. 1/16″ to 6″.

Shot Irregular shapes with lumps and bumps, but only cost effective alternative for steel in sizes less than 1mm. Inexpensive, sizes from 90 microns to 3mm.

Other forms Steel wire can be cut and formed to produce diagonals, ballcones (looks like a flattened ice cream cone), pins (rods), oval balls and other shapes.

The first of the “engineered” class of grinding media, glass beads (small balls) and balls were developed specifically for grinding applications where sand wasn’t available. Glass is manufactured in various grades (Lead-free Soda Lime, borosilicate, low alkali, black glass, and others) in sizes from 1 micron to 2 inches.

Good wear properties coupled with reasonable roundness means this is the best material to start with when conducting grinding trials. Low cost.

Glass balls are also available in precision grades and are used in optical resolution systems and as “spacers” for precision electronics. Colored glass balls are used for both engineering and decorative applications.