초록 ▼

To increase the extrusion speed for extrusion of light-weight metal such as aluminum, without incurring hot short cracks, or fissures, and retaining high-quality smooth surface of the extruded material, the region of the extrusion chamber immediately ahead of the extrusion die (3) is cooled by placi

To increase the extrusion speed for extrusion of light-weight metal such as aluminum, without incurring hot short cracks, or fissures, and retaining high-quality smooth surface of the extruded material, the region of the extrusion chamber immediately ahead of the extrusion die (3) is cooled by placing a cooling ring (12, 12′) between the bore (9) of the extrusion cylinder in which the ram piston (13) operates. The cooling ring may be a unitary structure, or a multi-part structure, in which an independent inner ring is located within a cooling ring (12). For mechanical strength, a prestressing outer ring (20) is shrink-fitted around the cooling ring. The outer ring is retained, for example by screws (24), on the cylinder (2) within which the extrusion chamber (9, 10) is located. The cooling fluid may be water, a vaporizable liquid, or a gas, and is separated from the billet (1) within the extrusion chamber.

대표청구항 ▼

The combination of apparatus for extrusion of a metal billet (1), particularly hot short crack sensitive metal such as aluminum and other light-weight metals, while maintaining a smooth surface finish, having an extrusion cylinder (2) defining an extrusion chamber (9) formed as a bore in a housing;

The combination of apparatus for extrusion of a metal billet (1), particularly hot short crack sensitive metal such as aluminum and other light-weight metals, while maintaining a smooth surface finish, having an extrusion cylinder (2) defining an extrusion chamber (9) formed as a bore in a housing; a ram piston (13) operable, at least in part, in said extrusion chamber; an extrusion die (3) positioned to receive extruded material of said billet, with means for cooling the billet in the region where the metal of the billet is subject to greatest deformation, said cooling means comprising a cooling ring (12, 12′) located immediately in advance－in the direction of extrusion－of the die (3), the cooling ring having an inner bore which matches the bore (9) of the extrusion cylinder and forms a coaxial extension of said bore at the side of the die, the axial length of said cooling ring (12, 12′) being less than twice the diameter of the bore; means (14, 15, 18, 26, 27, 28, 29) for circulating a cooling fluid in said cooling ring, while separating and isolating said cooling fluid from said billet, being closed off therefrom, and located in the region in which the major extent of deformation of the billet, as it is being extruded, occurs, said fluid circulating means being uniformly distributed about the chamber at a minimum diameter which is less than 1.5 times the diameter of the ram piston (13); and a stress accepting ring means (20) tightly surrounding said cooling ring (12, 12′), said stress-accepting ring means being secured to said extrusion cylinder.