高周波焼入れ粉末焼結ローラの面圧強さに関する研究 : 粉末粒子径および相対曲率半径の影響

概要

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In order to elucidate the influences of particle size of powder and relative radius of curvature on surface durability of induction-hardened sintered powder metal rollers, the rollers with a diameter of 30 mm and 60 mm made by three kinds of particle sizes were fatigue-tested under a sliding-rolling contact condition using two cylinders testing machines. The three kinds of particle diameters were under 45 ixm, 75μm〜106μm and 150μm〜250μm, respectively. The surface durability of the roller became higher as the relative radius of curvature decreased. The surface durability of the roller made by the smallest particle size was almost equal to that of the roller made by the intermediate particle size. While the surface durability of the roller made by the largest particle size was inferior to those of the other rollers. The smaller the particle size became, the smaller the pore size became and the lager the pore cluster factor by fractal dimension became. The failure mode of all rollers was spalling. The minimum depth of the spalling crack agreed almost with the depth of the peak amplitude of the ratio of orthogonal shear stress to Vicker's hardness. It was understood that the pore size and the pore cluster factor were important parameters to evaluate the surface durability of the sintered powder metal rollers.
1998-06-25