US2221299A - Extrusion apparatus - Google Patents

Description

Nov. 12, 1940.

J. B. JONES EXTRUSION APPARATUS Filed June 28, 1939 INVENTOR! Jornv B. Jouzs.

Patented Nov. 12, 1940 UNITED STATES EXTRUSION APPARATUS John B Jones, New Kensington, Pa., assignor to Aluminum Company of America, Pittsburgh, Pa, a corporation of Pennsylvania Application June 28, 1939, Serial No. 281,552

8 Claims.

. This invention relates to improvements in mechanism or apparatus for the production of hollow seamless shapes or sections by extrusion processes.

In known extrusion practice it has been customary in the production of hollow seamless sections to employ hollow metal billets, or metal charges, through an interior opening of which extends a mandrel terminating within an extrusion die orifice, the die orifice controlling the exterior configuration or contour of the final extruded shape or die-expressed product, and the mandrel serving to control the interior configuration or contour of the product. In this known form of extrusion apparatus, the mandrel was either held stationary with respect to longitudinal axial movement through the die orifice, or it was permitted to travel through the die orifice with the metal being extruded. In both instances, however, the mandrel was unsupported with respect to its end adjacent the exterior configuration-controlling die orifice.

It has likewise been known to extrude a section or shape from a solid metal billet or charge, without the use of a mandrel extending through the metal charge or billet. In this latter instance, what have been commonly termed porthole dies have been employed, wherein a stub mandrel adjacent the die orifice has been so arranged that the metal of the solid billet divides and flows under the influence of pressure around the mandrel and thereafter coalesces within a space defined by a portion of the mandrel'and the die orifice to produce a hollow seamless shape.

The three forms of extrusion apparatus above referred to have certain inherent structural limitations in so far as their operation and commercial production of satisfactory and acceptable extruded product are concerned. 'For example, the unsupported mandrel type of extrusion mechanism has usually resulted in the production of hollow, seamless, extruded sections which have inherent variations in wall thickness. This objection has been attributed to the fact that the free or unsupported end of the mandrel is subject to floating or shifting with respect to the exterior configuration-controlling die orifice.

As to the porthole die type of extrusion apparatus, it has been found that excessive pressures are necessary to force a solid metal billet through the, passages adjacent the stub mandrel, with the result that exceptionally high extrusion temperatures are developed with attendant die deterioration and breakage. This latter type of apparatus, however, has otherwise found increasing use and approval, in view of its more rigid mandrel-supporting means, as compared to the previously described extrusion apparatus incorporating a mandrel extending through the entire length of a hollow metal billet.

It is an object of the present invention to provide extrusion mechanism which is capable of incorporating those features of the porthole type extrusion apparatus, such as the rigid support for the stub mandrel which results in the commercial production of hollow, seamless, extruded sections having wall thicknesses maintained within close working tolerances, while at the same time provide an extrusion mechanism which will overcome the excessive pressures and high operating temperatures now associated with the porthole die type of extrusion apparatus.

It is a further object of this invention 'to provide a novel extrusion apparatus which incorporates the desirable features of known extrusion equipment, and which lends itself to ready adaption to many forms of extrusion apparatus now in use without any considerable reconstruction or modification of the same.

Other objects and advantages will present themselves *on consideration of the following specification when read in conjunction with the drawing appended hereto and forming a part hereof, in which:

Fig. 1 represents a sectional elevation through a portion of an extrusion press incorporating a die and mandrel arrangement fulfilling the objects'and advantages of the invention;

Fig. 2 isan end view of a mandrel-supporting annulus shown in assembled position in Fig. 1, and as viewed from the left in that assembly;

Fig. 3 is an end view in elevationof an exterior configuration-controlling die shown in assembled position in Fig. 1, and as viewed from the left in that assembly; and

Fig. 4 is a fragmentary sectional elevation of the die and mandrel arrangement disclosed in Fig. 1 as taken along the line IVIV of Fig. 2.

In its broadest aspect the apparatus of this invention comprises a female or exterior configuration-controlling die in cooperation with a mandrel member for controlling the interior contour or configuration of the seamless hollow section to be produced, the mandrel member being securely positioned with respect to that portion of the same that extendswithin the female die orifice, whereby the mandrel is supported against any objectionable shifting or floating with respect to the female die orifice.

Referring to a more specific description of the invention, reference being made to the drawing for a preferred form of apparatus incorporating the features of the invention, reference numeral l represents the head or forward platen of any well-recognized type of extrusion press. A billet cylinder H is disposed adjacent the head III, the

billet cylinder illustrated herein having the 'customary hardened steel liners or sleeves l2 and M, respectively, within its bore. A tool carrier I5 is provided for receiving and supporting the extrusion die assembly represented in its entirety by the reference numeral l6.

The extrusion die assembly it comprises a die holder l1, preferably in the form of an annulus, within a central bore of which are supported in abutting relationship an exterior configurationcontrolling female die member i8 (Fig. 3) and a mandrel-supporting annulus or member l9 (Fig. 2). In order that the die member 13 and annulus l9 may be secured in definite abutting relationship with respect to each other, suitable dowel pins 20 have been provided. In like manner a key 2|, in cooperation with a complementary keyway 22 extending into the interior bore of die holder l1 and exterior surface of die l8, insures alignment of the entire die assembly and mandrel-supporting annulus with respect to the die holder 11.

An interiorly shouldered ring or annulus 23, which is secured to the carrier l5 by means of any suitable fastening devices, such as the fiatheaded screws 24, is adapted to engage a complementary shouldered portion formed on the exterior of the tool holder l1, whereby means are provided for afilxing or securing the tool assembly l6 within the tool carrier HE. A back-up ring or block 25, together with a filler block 26, acts in a capacity to carry or transmit the extrusion pressures developed during an extrusion operation, to the carrier I5. This construction also provides means for rapid removal of the tool holder l1, and its associated tool assembly it, on the mere withdrawal of back-up block 25 and filler member 25, the removal of these latter elements permitting translation of the tool holder i1 towards the right (as viewed in Fig. 1), with subsequent vertical removal from the tool carrier l5.

The aforedescribed tool carrier [5, together with the associated elements supported therein, is preferably reciprocably mounted with respect to the billet cylinder II in such a manner that the vertical displacement of a suitable locking bar 2! permits translation of the tool carrier 15 toward and away from the billet cylinder H. A seal is provided between the tool holder l1 and billet cylinder H This seal preferably takes the form of an interiorly chamfered surface on liner It in engagement witlr a complementary exteriorly tapered surface on tool holder H.

-A mandrel 23 is provided for the purpose of controlling the interior contour or configuration of the hollow, seamless, extruded shape or section adapted to be produced by the apparatus of this invention. This mandrel 2B is preferably telescopically mounted with respect to the customary extrusion ram. Since the ram and telescopic connection with the mandrel is well known in the art, it has not been considered necessary to illustrate the same. The mandrel is provided, adjacent its forward, normally unsupported end, with an interior contour-controlling nose-piece 29 which is preferably, replaceably secured to the main body of the mandrel through the medium of a threaded connection 3ll.

The nose-piece 29, in its cooperative relationship with the mandrel 23 and mandrel-supporting annulus l9, constitutes one of the significant features .of this invention and is now described in more detail.

The mandrel nose-piece 29 is suitably constructed with a forwardly flaring shoulder or chamfer 3| which is preferably followed by a cylindrical centerlngiiand bearing portion 32, a

second forwardly tapering portion 33 being provided which connects the aforementioned centering portion with an interior configuration-controlling portion 34 extending into and preferably through the exterior configuration-controlling die orifice 35. The die orifice 35 is immediately relieved, as at 33, on its egress side.

Referring now to the mandrel-supporting annulus or member l9, this annulus is provided with a forwardly tapering or flared cavity or chamber 31, the flared wall of which is in spaced relation to and approximately in parallelism with the flared portions 3 i33 of the nose-piece 29 of the mandrel 28. Thus, an annular funnel-like passage is formed between the annulus l9 and the adjacent portion of the mandrel for directing flow 'of metal to the die orifice. The annulus is provided with narrow circumferentially-spaced mandrel-centering and supporting wings 38 preferably formed integral with the wall of the cavity 31 and extending radially inwardly to a position to engage the cylindrical surface 32 of the mandrel nose-piece, thereby supporting the mandrel against radial shifting relative to the die orifice. Each wing 38, there preferably being three wings, is chamfered, as at 39, for engagement with the chamfered surface 31 of the mandrel nose-piece,

which construction serves to positively position the mandrel with respect to its forward axial position in the die orifice 35. The tapered surface of the cavity 31 terminates in an aperture M which is preferably slightly larger, but otherwise a substantial counterpart of the die orifice 35. This construction presents a relatively fiat shoulder 42 adjacent the entrance to the orifice 35, which shoulder serves to insure a definite shearing edge for the metal being extruded.

In the operation of the mechanism of this invention, an extrusion billet or charge (not shown), pierced or otherwise provided with a longitudinal interior opening to receive the mandrel 28, is first charged into the billet cylinder II to substantially fill the interior bore of liner M. The ram (not shown) is thereafter advanced to project the mandrel 23 through the longitudinal opening in the billet and to bring its afiixed mandrel nose-piece 23 into positive, centered and abutting relationship with respect to annulus l9 and die 18 (Figs. 1 and 4). .In this position, the mandrel being positively, radially supported and centered as aforede scribed, the ram is reciprocated relative to its telescopically connected mandrel to initially force a portion of the metal of the billet forwardly to fill the unobstructed pertions of. chamber 31 and finally express or extrude the metal of the billet through the passage formed between the die orifice 35 and nosepiece portion 34 to produce the desired hollow,

seamless, extruded section.

35, which eliminates any variation in wall thickmandrel member extending through the entire length of the pierced billet and terminating within the die aperture in spaced relationship thereto, said mandrel having an exterior configuration within the die aperture which defines the interior configuration of the shape to be produced, and positive means associated with said die and mandrel, immediately adjacent the die aperture, for retaining and maintaining the mandrel in fixed position with respect to said die aperture.

2. In an extrusion apparatus for-producing hollow seamless sections from pierced billets, the combination with a fixed die having an aperture, of a mandrel extending through a billet to be extruded and having a reduced end portion terminating within said die aperture in spaced relation thereto, said aperture and said reduced portion of the mandrel defining the exterior and interior configuration of the metal extruded through the die, and means associated with said die and mandrel at a plurality of circumferentially-spaced points forwardly of said die aperture for maintaining said reduced portion of the mandrel in predetermined fixed position relative to said die aperture. I

3. In anextrusion apparatus for producing hollow seamless sectionsfrom hollow billets, a die having an aperturedefining the exterior configuration of the shape to be produced,a mandrel extending through the entire length of the hollow billet and terminating within the die aperture in spaced relationship thereto, said mandrel having an exterior configuration within the die aperture which defines the interior configuration of the shape to be produced, a mandrel-supportingmember engaging said mandrel forwardly of said die and having a passageway for flow of metal to said die, and means for holding said member in fixed position relative to said die.

4. In an extrusion apparatus for producing hollow seamless sections from pierced billets, the combination with a fixed die having an aperture, of a mandrel extending through a billet to be extruded, a nose-piece on the end of said mandrel and disposed within said aperture in spaced relationship thereto, said aperture and said nosepiece cooperating to define the exterior and interior configuration of the metal extruded through the die, and a plurality of circumferentiallyspaced members rigidly associated with said die and engaging said mandrel for holding said nosepiece in fixed position relative to said die aperture.

5. In an extrusion apparatus for producing hoilow seamless sections from pierced billets, the combination with a fixed die having an aperture, of a mandrel extending through a billet to be extruded and having a reduced end portion terminating within said die aperture in spaced relation thereto, said aperture and said reduced portion of the mandrel defining the exterior and interior configuration of the metal extruded through the die, an annulus disposed forwardly of said die and having a cavity forming an annular passageway for'fiow of metal along said mandrel to said die aperture, a plurality of wings on said annulus and engaging said mandrel at circumierentially-spaced points, and means cooperating with said annulus for rigidly holding it in predetermined position relative to said die.

6. In an extrusion apparatus for producing hollow seamless sections from pierced billets, a die having an aperture, an annulus associated with said die, means for maintaining said annulus in fixed position relative to said die, said annulus having a flared cavity forming a funnel-like passageway leading to said die aperture, a man-' drel extending through a billet to be extruded to a point adjacent said annulus, a nose-piece secured to the forward end of said mandrel and extending through said cavity and terminating within said aperture in spaced relation thereto, said aperture and said nose-piece cooperating to define the exterior and interior configuration of the seamless sections produced by the metal extruded through the die, and means disposed circumferentially of said annulus and extending radially across said cavity into supporting engagement with said nose-piece.

'7. In an extrusion apparatus for producing hollow seamless sections from pierced billets, a die having an aperture" defining the exterior configuration of the shape to be produced, an annulus associated with said die, means for maintaining said annulus in fixed position relative to said die, said annulus having a flared cavity forming a funnel-like passageway leading to said die aperture, a mandrel extending through a billet to be extruded to a point adjacent said annulus, a nosepiece secured to said mandrel and having a terminal portion located within said die aperture in spaced relation thereto to define the interior configuration of the shape to be produced, said annulus being formed with a plurality of circumferentially-spaced wings extending radially across said cavity into supporting engagement with said nose-piece at a point intermediate said terminal portion and the forward end of said mandrel.

8. In an extrusion apparatus for-producing hollow seamless sections from hollow billets, a die having an aperture defining the exterior con-' figuration of the shape to be produced, an annulus associated with said die, means for mainacross said cavity into supporting engagement with said nose-piece at a point intermediate said terminal portion and the forward end of said mandrel, the exterior faces of said nose-piece forwardly and rearwardly of said point of engagement of said wings with the nose-piece being flared in parallelism with the flared wall of said cavity in said annulus.

JOHN B. JONES.

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