2018 Volume 59 Issue 692 Pages 171-175
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.
