In the case of large components, shot peening is generally performed by moving peening equipment that follows a trajectory on the component surface using a robot. In this study, we aimed to obtain a functional approximation of the intensity (arc height of the Almen strip) distributions in the shot stream. The intensity distributions using various peening times and standoff distances were measured under two different experimental conditions. The measured intensity distributions were approximated by modified Gaussian distribution functions, which included the saturation curve. Three coefficients in the functions depended on the peening time and the standoff distance. For tilted shot peening, the intensity distributions were more complex because the standoff distance at each Almen strip was different. The intensity distributions of the tilted plates calculated using the modified Gaussian distribution function, which considered the variation in the standoff distance, were in good agreement with the experimental results. The intensity distributions of twice-shot peening differed from those of once-shot peening because the second peening area overlapped the first peening area. The modified Gaussian distribution function and the saturation function were used to determine the intensity distribution of a twice-shot-peened sample. These calculated values were in good agreement with the experimental results.
The effects of the surface roughness of a dull roll and rolling reduction on the glossiness and surface roughness of dull-finished phosphor bronze were investigated. It was found that the glossiness was reduced by dull finishing from 650 to less than 10 GU in any dull roll whose nominal surface roughness was more than 8 μmRz. The smallest reduction ratio to obtain a surface of Ra > 1 μm was 5%. The surface of 12, 16, and 20 μmRz dull rolls could not be completely transcribed to the surface of the phosphor bronze plate even with the rolling reduction ratio of 10%. This is presumably because the rolling force was insufficient to fill the valleys of the surface of dull rolls. When the surface roughness Ra of dull-finished phosphor bronze was more than 0.2225 μm, which means the Rayleigh criterion was satisfied, the glossiness drastically decreased. When the roughness was larger than 0.5 μmRa, the glossiness was proportional to the inverse of the square of surface roughness, which is in good agreement with a theoretically proposed equation.
The power consumption of motors is considered to account for ～40% of total power consumption in the world. The demand for reducing the power consumption of motors, that is, improving their efficiency, has been increasing. One measure to meet this demand is the use of an amorphous motor with a motor core made of amorphous alloy foil. However, amorphous alloy is highly brittle and the material itself is a thin foil. Therefore, the production of motor cores by blanking using a highly efficient press machine has been considered difficult thus far. The authors aimed at the practical application of highly efficient cutting of amorphous alloy foil by warm blanking. The effect of various blanking conditions on the properties of the cut surface and tool wear was experimentally examined. The results indicate that cut surfaces free from defects such as cracks can be stably obtained by blanking at a heating temperature in the range of 200℃, even under relatively large clearance. In addition, it was experimentally demonstrated that the excellent magnetic properties of amorphous alloy foil are not lost during warm blanking in the range of 200℃ and that blanking tools are not deteriorated by heat.