Elastic moduli of grinding wheel based on a simplified model.

The elastic modulus of grinding wheel is one of the very important mechanical properties on the grinding performance and theory of grinding. To obtain this value, the direct measurements on grinding wheels or the mathematical methods from the theoretical relation among volume fractions of grains, bonds and pores that are constituents of a grinding wheel and from each elastic moduli of the constituents are tried in the past. No simple and effective explanation was, however, established between the elastic modulus and composition of grinding wheel. In this paper, a simplified structure model was contrived and from this model, was induced the theoretical formula of the elastic modulus. The elastic modulus of grinding wheel is expressed as E, elastic moduli of grains and bonds as Eg and Eb, volume fractions of abrasive grains and bonds in the grinding wheel as Vg and Vb. Then, following relation is obtained: E={1/Vg1/3Eg+3(1-Vg1/3)2/VbEb}-1To verify this formula, test specimens of vitrified grinding wheel were trial-manufactured, based on the grain percentage: 43-51%, grade (hardness): H-R, and grain size: #46-#120 of WA, #60 and #80 of GC, and the elastic moduli of specimens were measured by bending method.The specimen size is 5(thickness)×12.8(width)×120mm(length). The obtained values were compared with the calculated ones from the formula, and the results showed a good agreement in each combination of the volume fractions of grains and bonds, employing elastic modulus of WA grain Eg: 35.7×105kgf/cm2 and of vitrified bond Eb: 6.31×105kgf/cm2. The elastic moduli of specimens are in the range of 1-8×105kgf/cm2. Therefore, the values of elastic moduli from the simplified model of grinding wheel are inferred to be reasonable.