Abstract: A surface treatment method of an aluminum extruding die having wear resistance and separation resistance is provided. The surface treatment method of an aluminum extruding die includes a first nitriding treatment step for forming a diffusion hardened layer 6 containing carbon and nitrogen at a surface layer portion of a die main body 5 by heating and retaining the die main body 5 made of tool steel in a nitriding gas atmosphere containing carburizing gas, and a second nitriding treatment step for forming a compound layer 7 substantially not containing carbon on a surface of the diffusion hardened layer 6 by heating and retaining the die main body 5 to which the first nitriding treatment was executed in a nitriding gas atmosphere not containing carburizing gas.

Abstract: An apparatus for automatically inserting a plug in and to a predetermined position therein a raw pipe such as an aluminum pipe which is to be drawn for instance in a drawbench. The apparatus comprises a suppport roller which supports a plug-supporting rod at its intermediate portion near to an end of the rod, the support roller bearing a lower surface of the portion and being movable along the plug-supporting rod. The apparatus further comprises a pipe-transporting device for transporting the raw pipe, which device grips both ends of the raw pipe so as to move it towards the plug-supporting rod in a direction in alignment with an axis of said rod. A pusher protrudes forward from the pipe-transporting device so that the device starts to carry the support roller at a given instant whereby the raw pipe is prevented from directly riding the support roller and is thus protected from being scratched, and forcible pressing of the plug onto an inner surface of the raw pipe being also avoided.

Abstract: A pipe centering apparatus is of such a structure that pipes of certain kinds such as aluminum short pipes transported by a conveyor are centered with their longitudinal centers aligned with each other, before the pipes are subjected to chamfering or other processes. The pipe centering apparatus in the invention comprises a pair of right and left gears in mesh with each other and rotatably mounted on a main frame, a pair of right and left racks respectively in mesh with the right and left gears, and a pair of right and left regulators respectively secured to the right and left racks so as to come into contact with ends of the pipes, wherein the gears are rotated to cause the regulators to move towards each other and to contact the pipe ends, thereby precisely centering the pipes even where the pipes are not of strictly the same length.

Abstract: Apparatus for automatically forming pointed ends for raw metal pipes such as aluminum pipes subject to a drawing process, the pointed end of the pipes being of a reduced diameter convenient for the drawing process. A transporting device moves each raw pipe, which is in alignment with an axis of a pipe inlet of a swaging machine for producing the pointed ends, to a position below the inlet. Each pipe is raised by a lifting device to a height of the pipe inlet so as to be chucked by a gripping device which moves forward to insert a leading end of the pipe into the inlet. The lifting device and the raw pipe are kept out of contact with each other while the leading end is being processed to form the pointed end at the inserted end in the swaging machine whereby efficiency and productivity are improved for the process.

Abstract: A metallic pipe-cutting apparatus is constructed to cut elongate metallic pipes such as aluminum pipes into shorter pipes of a predetermined length, and comprises a main body, a chuck disposed rearwardly of the main body so as to hold trailing ends of the elongate metallic pipes, and a supporter disposed forwardly of the main body, with the main body interposed between the chuck and the supporter. The supporter comprises supporting pins which are to be inserted in leading ends of the pipes whose trailing ends are clamped by the chuck, so that the pipes clamped at their both ends are moved intermittently a predetermined distance so as to be successively cut into the predetermined length, with their outer peripheral surfaces not being scratched or flawed due to sliding contact with clampers or other members.

Abstract: A method for producing aluminum drums having highly smooth surfaces, the method including two steps; the preparation of an aluminum pipe by extrusion, and the drawing of the pipe through a die unit, wherein the die unit comprises a die and a plug, the die having an approach angle of 45.degree. to 75.degree. C. and the plug having an approach angle of 10.degree. to 20.degree..