Á¤¼ö¾ÐÃâ(ð¡â©äâõó; hydrostatic extrusion)

With the hydrostatic extrusion the billet in the container is surrounded with fluid media, is called also hydrostatics medium. The container space is sealed on the stem side and on the die side, so that the penetrating stem can compress the hydrostatics medium on pressing power, without the stem touches the billet. Also during extrusion the stem does not touch the billet. The rate, with which the billet moves when pressing in the direction of the die, is thus not equal to the ram speed, but is proportional to the displaced hydrostatics medium volume. For this process it is substantial that the billet seals the container space on applying the pressing power in the hydrostatics medium against the die, since otherwise the pressing power cannot be developed. It is thus a conical die and a careful sharpening billet a prerequisite of the process. Since the billet does not touch the container's wall, but between billet and container hydrostatics medium exists, prevails negligibly small friction of a liquid at the billet surface. Only the friction between billet and die is of importance for the deforming process. Likewise pressing of the billet is unnecessary at the press begin.