Forming of materials

Claim 2

Apparatus for producing from a workpiece a product of reduced cross-section comprising a workpiece, an orifice defining the reduced product cross-section, means for applying a bulk compressive stress to the whole of the workpiece to influence the workpiece to extrude through said orifice, a tool having a working face of smaller cross-section than the workpiece and mounted for application to a localised region of the bulkstressed workpiece adjacent said orifice, and means for effecting relative rotary movement between the tool and the workpiece to apply an additional compressive stress at said localised region to influence the localised region to extrude through said orifice, whereby the material of the workpiece is subjected to an additional compressive stress at said localised region thereof and is formed through the orifice defining the product crosssection under the combined influence of said bulk compressive stress and said additional compressive stress.

Claim 3

Apparatus according to claim 1 including means for rotating the tool in a circular path with the working face thereof in pressure contact with the material of the workpiece.

Claim 4

Apparatus according to claim 1 comprising a container, the bore of the container having a tapered end reducing to a smaller cross-section, means for applying pressure to the workpiece in the container so as to set up a bulk compressive stress in the whole of the workpiece and so as to force the corresponding end of the workpiece into the tapered end of the bore of the container, the tool comprising a rotary member with an end face having a projecting tool member, the tool member having a material working face, means for rotating the rotary member with the end face thereof in contact with the forward end of the workpiece in the tapered end of the bore of the container so that the tool member is moved in a circular path with its material working face in pressure contact with the material of the workpiece.

Claim 5

Apparatus according to claim 3 wherein an orifice defining the product cross-section is formed in the material working face of the tool member.

Claim 6

Apparatus according to claim 3 wherein an orifice defining the product cross-section is formed in the face of the rotary member forward of the material working face of the projecting tool member, which is of solid form.

Claim 7

Apparatus according to claim 3 wherein the rotary member has a plurality of projecting tool members each having an associated orifice defining the product cross-section.

Claim 8

Apparatus according to claim 5 wherein a plurality of orifices defining the product cross-section are formed in the face of the rotary member forward of the material working face of the projecting tool member.

Claim 9

Apparatus according to claim 3 wherein means are provided for the feeding of lubricant to the face of the rotary member behind the projecting tool member.

Claim 10

Apparatus according to claim 3 wherein the rotary member is sleeve shaped and is rotatably mOunted on a stationary stem located within the sleeve, the tool member being formed projecting from the annular end face of the sleeve shaped rotary member, the rotary member being rotated with said annular end face and the corresponding end of the stationary stem in contact with the workpiece.

Claim 11

Apparatus according to claim 9 wherein the end of the stationary stem is pointed and projects from said sleeve whereby the pressure applied to the workpiece in the container causes feed of the material of the workpiece over the pointed end of the stationary stem into the region of the annular end face of the sleeve shaped rotary member.

Claim 12

Apparatus according to claim 3 wherein a mandrel is supported coaxially in the container to adapt the apparatus for handling of a tubular workpiece which fits about the mandrel in the container, the pressure applied to the workpiece in the container causing feed of the material of the workpiece into the tapered end of the bore of the container about the mandrel, the end face of the rotary member having held in contact with the annular end face of the billet in the forward part of the tapered end of the bore of the container so that the tool member projecting from the end face of the rotary member is moved in a circular path to traverse said annular end face of the workpiece.

Claim 13

Apparatus according to claim 1 in which the tool is fixed against rotation, means for rotating the workpiece with the localised region thereof at all times in pressure engagement with the fixed tool.

Claim 14

Apparatus according to claim 12 in which the means for rotating the workpiece comprises a rotatable mandrel supporting the workpiece at the localised region thereof and means for keying the mandrel to the end of the workpiece.

Claim 15

Extrusion apparatus for producing from a workpiece a product of reduced cross-section comprising an extrusion orifice defining the product cross-section, means for locating a workpiece adjacent the inlet of the extrusion orifice, means for applying a bulk compressive stress to the whole of the workpiece to influence the workpiece to extrude through said orifice, means for applying an additional localised compressive stress at a localised region of the workpiece adjacent the inlet end of said orifice to influence the localised region to extrude through said orifice, said last mentioned means comprising a tool having a working face of smaller cross-section than the workpiece and mounted for application to said localised region adjacent said orifice, and means for effecting relative rotary movement between the tool and the workpiece to effect application of said additional localised compressive stress, said tool working face being located radially outwardly from the rotational center of said rotary movement and oriented so as to oppose said relative rotary movement and thus compressively stress said localised region of the workpiece adjacent said orifice, whereby the material of the workpiece is subjected to an additional compressive stress at said localised region thereof and is formed through the orifice defining the product cross-section under the combined influence of said bulk compressive stress and said additional compressive stress.

Claim 16

Extrusion apparatus for producing from a workpiece a product of reduced cross-section comprising an extrusion orifice defining the product cross-section, means for locating a workpiece adjacent the inlet of the extrusion orifice, means for applying a bulk compressive stress to the whole of the workpiece to influence the workpiece to extrude through said orifice, means for applying an additional localised compressive stress at a localised region of the workpiece adjacent the inlet end of said orifice to influence the localised region to extrude through said orifice, said last mentioned means comprising a tool having a working face of smaller cross-section than the workpiece and mounted for application to said localised region adjacent said orifice, and means for effecting relative rotary movement between the tool and the workpiece to effect application of said additional localised compressive stress, said tool working face being located radially outwardly from the rotational center of said rotary movement and oriented so as to oppose said relative rotary movement and thus compressively stress said localised region of the workpiece adjacent said orifice, whereby the material of the workpiece is subjected to an additional compressive stress at said localised region thereof and is formed through the orifice defining the product cross-section under the combined influence of said bulk compressive stress and said additional compressive stress.