A method is used to manufacture a tube having a hollow interior for housing an axle shaft. The tube is formed in a single machine having a fixed base and a single press structure movable toward the fixed base. The single machine includes first and second die assemblies coupled to the fixed base and first and second mandrels coupled to the single press structure. The method includes the steps of placing a billet into the first die assembly, pressing the billet into the first die assembly with the first mandrel to producing a pre-formed billet, and moving the pre-formed billet from the first die assembly to the second die assembly. THE method further includes the steps of pressing the pre-formed billet into the second die assembly with the second mandrel to elongate the pre-formed billet and form a hollow interior therein to produce an extruded tube.

A method is used to manufacture a tube having a hollow interior for housing an axle shaft. The tube is formed in a single machine having a fixed base and a single press structure movable toward the fixed base. The single machine includes first and second die assemblies coupled to the fixed base and first and second mandrels coupled to the single press structure. The method includes the steps of placing a billet into the first die assembly, pressing the billet into the first die assembly with the first mandrel to producing a pre-formed billet, and moving the pre-formed billet from the first die assembly to the second die assembly. THE method further includes the steps of pressing the pre-formed billet into the second die assembly with the second mandrel to elongate the pre-formed billet and form a hollow interior therein to produce an extruded tube.

An adjustable diameter die assembly for extruding a heated and malleable workpiece being forcefully moved downstream includes a die having a first ring and a second ring spaced apart from the first ring, the die having an axial portion extending intermediate the first and second rings that defines a throughbore having an axial diameter that is adjustable. The adjustable diameter die assembly includes a piston/cylinder combination operatively coupled to the die that, when actuated, causes (1) a compression of the first and second rings toward one another such that the axial diameter is decreased or (2) a stretching of the first and second rings away from one another such that the adjustable axial diameter is adjusted, respectively.

An adjustable diameter die assembly for extruding a heated and malleable workpiece being forcefully moved downstream includes a die having a first ring and a second ring spaced apart from the first ring, the die having an axial portion extending intermediate the first and second rings that defines a throughbore having an axial diameter that is adjustable. The adjustable diameter die assembly includes a piston/cylinder combination operatively coupled to the die that, when actuated, causes (1) a compression of the first and second rings toward one another such that the axial diameter is decreased or (2) a stretching of the first and second rings away from one another such that the adjustable axial diameter is adjusted, respectively.

A friction stir processing system can include a rotatable die assembly. The rotatable die assembly can include a die body and a plurality of die segments. The die body includes a die base and a die stem. The die stem extends axially from the die base, the die stem defines an extrusion cavity, and the die body is formed from a first material. The plurality of die stems are coupled to the die stem. The plurality of die segments are disposed around the extrusion cavity to collectively form a die surface opposite to the die base. The plurality of die segments are formed from a different material than the die body.

In extrusion processing in which diameter reduction is performed by pressing a raw pipe having a core bar inserted therein into a die having a small inner diameter portion on its tip end side, a differential thickness pipe having a thick-walled portion at its tip end can be molded using a core bar having a small cross-section portion formed at its tip end. It is also possible to mold a differential thickness pipe having a thick-walled part at an intermediate axial position by using a raw pipe having a thin-walled portion at its tip end. For example, such a raw pipe can be molded by extrusion processing using a core bar having no small cross section portion at its tip end, prior to the above-described formation of the thick-walled portion. When higher dimensional accuracy is required, a so-called “counter punch” may be used in the formation of the thick-walled portion.

In extrusion processing in which diameter reduction is performed by pressing a raw pipe having a core bar inserted therein into a die having a small inner diameter portion on its tip end side, a differential thickness pipe having a thick-walled portion at its tip end can be molded using a core bar having a small cross-section portion formed at its tip end. It is also possible to mold a differential thickness pipe having a thick-walled part at an intermediate axial position by using a raw pipe having a thin-walled portion at its tip end. For example, such a raw pipe can be molded by extrusion processing using a core bar having no small cross section portion at its tip end, prior to the above-described formation of the thick-walled portion. When higher dimensional accuracy is required, a so-called “counter punch” may be used in the formation of the thick-walled portion.

A method is used to manufacture an article using a machine having a fixed base and a press structure movable toward the fixed base. The machine also includes a die assembly and a container both coupled to the fixed base. The machine further includes a mandrel assembly comprising a rotatable platform coupled to the press structure and having a first platform mandrel aligned with the die assembly and a second platform mandrel aligned with the container. The method includes the steps of placing a first starting component into the die assembly, pressing the first starting component to form the article, moving the second platform mandrel into the container simultaneously with the step of pressing the first starting component, and rotating the rotatable platform to align the second platform mandrel with the die assembly and to align the first platform mandrel with the container.

If a mandrel for extruding metal pipes, having two axially offset pressing surfaces with different radial embossing and having a transition region between these two pressing surfaces has a support surface in the transition region then the negative effect of narrowing, which arises owing to the mandrel shifting from a first pressing position, in which the first of the two pressing surfaces interacts with a die, to a second pressing position, in which the second pressing surface interacts with the die, can be minimized.

If a mandrel for extruding metal pipes, having two axially offset pressing surfaces with different radial embossing and having a transition region between these two pressing surfaces has a support surface in the transition region then the negative effect of narrowing, which arises owing to the mandrel shifting from a first pressing position, in which the first of the two pressing surfaces interacts with a die, to a second pressing position, in which the second pressing surface interacts with the die, can be minimized.