PURPOSE: To manufacture an accurate metallic disk with excellent flatness by coining by increasing the applied quantity per unit area of lubricants at the center part of surface of disklike metallic material than that of peripheral part and in the range of specific times and under.
CONSTITUTION: When disklike metallic material 1 is held between two dies with smooth pressure surface and is coined in a die ring regulating the expansion limit of material in the diametral direction, the coining is performed by increasing the applied quantity per unit area of lubricants at the center part 3 of the disk than that of its surrounding part 2 and being taken in the range of double and under. The preceeding of the deformation of the outside part with small deformation resistance at the early stage of working is prevented and the accurate metallic disk with excellent flatness and stable dimensional accuracy is manufactured. In case of doughnut disklike metallic plate 5, the supplied quantity of lubricants is increased at the part of the doughnut-like center face 8.
HATA TOMOKATSU
INABAYASHI YOSHITO
YAMAZAKI ATSUSHI
KAWASAKI STEEL CO
ITOH C & CO LTD