Patent ID: 9364894
Filing Date: 2016-06-14
CPC Classification: B22C,B22D

Claim Text:
1. A method of treating a surface of a cavity of a die for casting comprising step A of treating the surface by sprayed particles where first particles to be sprayed of a spherical shape having a hardness that is greater than that of the die for casting are sprayed against the surface of the cavity and thus form first dimples of hemispherical shapes that have no pointed corners on the surface of the cavity, wherein the first dimples formed to have shallow hemisphere shapes, the diameters of the openings of the dimples that are being ten or more times greater than the depths of the dimple; further comprising, after step A of treating the surface by first particles is performed, step B of treating the surface by sprayed particles that form second dimples on the surface of the cavity by having second particles that have smaller diameters than those of the first particles and that have a hardness that is higher than that of the die for casting sprayed against the surface, the method forming the surface of the cavity that is made up of the first dimples and the second dimples intermingled with each other and having second dimples formed within the first dimples; and where the surface of the cavity thus formed has the first dimples uniformly dispersed on the surface, wherein the surface of the cavity is treated in step B in such a way that the traces of treatment, are eliminated from the surface thereby improving the fluidity of the molten metal.