초록 ▼

A method for producing a high strength workpiece material includes the steps of: placing an alloy material 10 into a central space of a cylindrical mold 2; vertically compressing both end faces of the material in the central space with a press member 5 and a first support member 3, thereby causing o

A method for producing a high strength workpiece material includes the steps of: placing an alloy material 10 into a central space of a cylindrical mold 2; vertically compressing both end faces of the material in the central space with a press member 5 and a first support member 3, thereby causing one lengthwise end of the material to flow radially outward along an end face of the cylindrical mold 2 to form an expanded part; bringing the press member 5 into contact with a lengthwise end face of the expanded part so as to press the expanded part against the end face of the cylindrical mold 2; and increasing the distance between the press member 5 and the end face of the cylindrical mold 2 while decreasing the distance between the press member 5 and the first support member 3, thereby continuously causing the radially outward flow from one end to another end of the material to gradually increase the thickness of the expanded part.

대표청구항 ▼

1. A method for producing a high strength workpiece material, comprising the steps of: placing a cylindrical mold having a vertically extending central space into a vertically extending central opening of a fixed mold in a vertically movable manner;placing a small diameter, long metal or alloy start

1. A method for producing a high strength workpiece material, comprising the steps of: placing a cylindrical mold having a vertically extending central space into a vertically extending central opening of a fixed mold in a vertically movable manner;placing a small diameter, long metal or alloy starting material into a central space of the cylindrical mold;vertically compressing both end faces of said small diameter, long starting material in said central space with a first press member and a support member, thereby causing one lengthwise end of said starting material to flow radially outward along an end face of said cylindrical mold to form an expanded part;bringing a second press member into contact with a lengthwise end face of said expanded part so as to press said expanded part against the end face of said cylindrical mold; andincreasing a distance between said second press member and the end face of said cylindrical mold while decreasing a distance between said first press member and said support member, thereby continuously causing the radially outward flow from one end to another end of said small diameter, long starting material to gradually increase a thickness of said expanded part and finally produce a large diameter, short billet having an outer diameter surface abutting against a wall surface of the central opening of the fixed mold. 2. The method according to claim 1, wherein said first press member and said second press member are integrally advanced and said cylindrical mold is retracted by an amount larger than the advancement amount of said press members. 3. The method according to claim 1, further comprising the step of, after increasing the thickness of said expanded part and producing said large diameter, short billet, vertically compressing only a central region of said billet to form a recess. 4. The method according to claim 1, further comprising the step of, before increasing the thickness of said expanded part, vertically compressing only a central region of said starting material to form a recess. 5. The method according to claim 1, further comprising the step of, after increasing the thickness of said expanded part and producing said large diameter, short billet, removing a central region of said billet by machining. 6. The method according to claim 1, wherein said starting material is an ingot. 7. The method according to claim 1, wherein said starting material is a powder compact. 8. The method according to claim 7, wherein said starting material includes a fine powder compact disposed on the support member side and a coarse powder compact disposed on the first press member side. 9. The method according to claim 1, wherein said starting material includes a first material which is disposed on the support member side and a second material which is of a different kind from that of said first material and disposed on the first press member side. 10. The method according to claim 1, wherein said starting material is a light alloy. 11. A high-strength workpiece material producing apparatus for plastic-working a small diameter, long metal or alloy starting material into a large diameter, short billet, comprising: a fixed mold having a vertically extending central opening;a cylindrical mold having a vertically extending central opening for receiving said small diameter, long starting material and being placed into the central opening of the fixed mold in a vertically movable manner;a support member for supporting said starting material in said central opening from one end side;a first press member for pressing said starting material in said central opening from another end side;a second press member for pressing from another end side an expanded part of said starting material which is expanded radially outward along an end face of said cylindrical mold when said starting material is pressed by said first press member; anddistance control means for increasing a distance between said second press member and said cylindrical mold while decreasing a distance between said first press member and said support member so as to finally produce said large-diameter, short billet having an outer diameter surface abutting against a wall surface of the central opening of the fixed mold. 12. The apparatus according to claim 11, wherein said first press member and said second press member are provided integrally. 13. The apparatus according to claim 11, wherein said first press member has a protrusion for forming a recess in a central region of said starting material.