US3756054A

US3756054A - Method of manufacturing rods or wire of compound material having non-circular cross-section by hydrostatic extrusion

Info

Publication number: US3756054A
Application number: US00224090A
Authority: US
Inventors: J Nilsson
Original assignee: ASEA AB
Current assignee: ABB Norden Holding AB
Priority date: 1971-02-12
Filing date: 1972-02-07
Publication date: 1973-09-04
Anticipated expiration: 1990-09-04
Also published as: NL7201769A; FR2125375B1; GB1369920A; CA956267A; DE2204257A1; SE364885B; FR2125375A1

Abstract

A wire or rod having an aluminum or aluminum alloy core and a copper or copper alloy casing is produced by hydrostatic extrusion of a compound billet through a die having a conical inlet with an outerpart with a cone angle between 70* and 115* and an inner part with a cone angle between 130* and 150*, the diameter of the inner part being substantially equal to the greatest dimension of the die opening.

Description

Umted States Patent 1 1 1111 3,756,054 Hilsson 1451 Sept. 4, 1973 METHOD OF MANUFACTURING RODS OR [56] References Cited WIRE OF COMPOUND MATERIAL HAVING UNITED STATES PATENTS NON-CIRCULAR CROSS-SECTION BY 3,620,059 11 1971 Nilsson 72/60 HYDROSTATIC EXTRUSION 3,583,204 6/1971 Nilsson 72/467 Inventor: Jan Nilsson, Robertsforsa Sw 2,218,459 /1940 Smger 72/467 [73] Assignee: Allmanna Svenska Elektriska Primary Examiner-Richard J. Herbst Atkiebolaget, Vasteras, Sweden Att0rney-Jennings Bailey, Jr.

1 [22] F1 ed Feb 7, 1972 ABSTRACT [21] Appl' 224,090 A wire or rod having an aluminum or aluminum alloy core and a copper or copper alloy casing is produced Foreign Application p i Data by hydrostatic extrusion of a compound billet through a die having a conical inlet with an outerpart with a Feb. 12, 1971 Sweden 1844/71 cone ang e bet ee and 1 5 a an inner p with 52 vs. C]. 72/60, 72/467 8 3 angle between the diameter 51 1111. C1. B21c 3/10 "3 ""F subsemlally equal the greatest [58] Field of Search 72/60, 253, 467

6 Claims, 4 Drawing Figures I I A f 2 2 I r2 7 y I2 -u 2-: -/3 l 1 V T E 8 1 0 Painted Sept. 4,1973

Fig

2 Sheets-Sheet 1 Patented Sept. 4, 1973 3,755,054

2 Sheets-Sheet 2 METHOD OF MANUFACTURING RODS OR WIRE OF COMPOUND MATERIAL HAVING NON-CIRCULAR CROSS-SECTION BY HYDROSTATIC EXTRUSION BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing rods or wire having non-circular crosssection, from compound material having a core of aluminum or an aluminum alloy and a casing of copper or a copper alloy surrounding the core, by means of hydrostatic extrusion.

2. The Prior Art It is known to use a compound billet for such an extrusion process formed of a core of aluminum and a casing of a copper tube surrounding the core. The billet is inserted in a pressure chamber containing a pressure medium. Under influence of a high all-round hydrostatic pressure, the billet is extruded through an opening in a die and thus shaped to a product having the desired cross-section. In order to join the core and the casing, they are sealed together at the rear end of the billet, for example with a sealing ring or a lid of elastomeric material which prevents the pressure medium from penetrating between the core and the surrounding tube.

The prior applications of Burstrom, S.N. 32,195, filed Apr. 27, 1970 and Nilsson, S.N. 758,308, filed Sept. 9, 1968 describe hydrostatic extrusion of compound products using a core of one material and a casing of another material. The die used for the extrusion process has a conical inlet opening. For hydrostatic extrusion the cone is normally very pointed, having a cone angle of about 45. The use of dies with such pointed cones has produced satisfactory results when extruding homogenous material and if it is possible to perform the extrusion at relatively low pressure. So far dies having relatively pointed cones, usually with a cone angle between 45 and 75, have been used for extruding compound material having an aluminum core and copper casing.

Wire or sections having non-circular cross-section, particularly having rectangular crosssection and large side ratio, covered with a thin copper casing have been difficult to extrude. The material in the casing becomes thicker on the short sides than on the long sides. The layer becomes thinnest in the middle of the long sides and the material in the aluminum core may break through the copper layer.

SUMMARY OF THE INVENTION It has been found that the geometrical shape of the die has an enormous influence on the result of the extrusion process, particularly when the product being extruded has a rectangular cross-section. According to the invention, the inlet of the die has inner and outer parts of differing cone angles, the angle of the inner part being greater than that of the outer part. Better results are obtained by extruding wire or sections in a die having a double conical inlet opening in accordance with the invention than by extrusion through a die having a conventional single-cone inlet opening, and sections having smaller copper reduction area can be produced. The extrusion must be carried outwith an extrusion ratio exceeding 20, but it preferably exceeds 50.

The extrusion ratio should preferably lie between and 250, but may be as high as 500.

The double conical inlet opening of the die should be shaped so that the outer, first conical part is more pointed than the inner, second conical part. The diameter at the transition between the conical parts of the inlet opening should be approximately equal to the greatest dimension of the die opening. For a rectangular extrusion opening, therefore, the diameter of the transition should be approximately equal to the diagonal of the rectangle. The angle of the first cone should be 70- and the angle of the second cone lS5. Particularly good results have been achieved using angles of 7585 and l45, respectively.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be described in more detail with reference to the accompanying drawings.

FIG. 1 shows schematically a section through a pressure chamber during extrusion of a billet,

FIG. 2 shows on a larger scale a view of the die from the inlet side and;

FIGS. 3 and 4 sections through the die on the lines A-A and B-B of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the drawings 1 designates a press stand and 2 a pressure-generating plunger arranged in a hydraulic press, not otherwise shown, in which there is a cylinder for operation of the plunger 2. The pressure chamber includes a high pressure cylinder 3 constructed of a steel cylinder 4, a strip mantle 5 of rectangular highstrength strip metal wound on under pre-stressing, and end pieces 6. Between the end pieces 6 and a spacer 7,

sealing rings

8 and 9 are arranged to provide seals between the cylinder 4 and the extrusion die 10 and the piston 2, respectively. In the pressure chamber is a billet 11 comprising a core 12 of aluminum or an aluminum alloy and a casing 13 of copper or a copper alloy surrounding the core. At the inner end of the billet there is an annular groove 14 in the core in which lies a ring 15 which prevents the pressure medium 16 from penetrating between the core and the casing. In this way the surfaces are kept free from contamination and a high pressure is obtained between the core and the casing, which gives good adhesion. The adhesion can be further improved by providing the core 12 with an additional groove 18. An extruded bar is designated 17.

In FIGS. 2 4, 20 designates the double conical inlet opening. 21 is the outer, first conical part of the inlet opening and 22 its inner, second conical part. The cone angles are designated a and I3 The rectangular extrusion opening is designated 23 and its diagonal D, the width B and the height B. At the transition between the

conical parts

21 and 22 the diameter is approximately equal to the diagonal D of the rectangle 23. The angle a should be 70l 15 and the angle B l25l55. Extremely good results have been obtained in dies having x= 80 and B= I claim:

1. Method of manufacturing rods or wire of compound material, having non-circular cross-section, with a core consisting essentially of aluminum and a casing consisting essentially of copper surrounding the core, by means of hydrostatically extruding a billet composed of a core and a casing surrounding the core and sealed to the core at the rear end of the billet, which comprises inserting said billet in a pressure chamber and extruding the billet under the influence of a hydrostatic pressure in a pressure medium in the chamber surrounding the billet through a die with an opening shaped to the desired cross-section, the die having a double conical inlet opening (20) and the outer, first conical part (21) having a cone angle (a) between 70 and 1 and the inner, second conical part (22) having a cone angle (B) between 130 and 150, the extruding ratio being greater than :1.

2. Method according to claim 1, in which the extrusion ratio is between 50:1 and 500:1.

3. Die for hydrostatically extruding sections having noncircular cross-section and a core of aluminum and easing of copper the die (10) having a double conical inlet opening (20) and the outer, first conical part (21) having a cone angle (a) between and 1 15 and the inner, second conical part (22) having a cone angle (B) between 130 and 150.

4. Die according to claim 3, in which the diameter at the transition between the first and second conical parts (21,11) of the inlet opening (20) is approximately equal to the largest dimension D of the die opening.

5. Die according to claim 3, in which the die opening (23) is rectangular and the diameter at the transition between the first and second conical parts (21, 22) of the inlet opening (20) is approximately equal to the length of the diagonal (D) of the die opening (23).

6. Die according to claim 3, in which the cone angle (a) of the first conical part (21) is between and and the cone angle (B) of the second conical part (22) is between and l45.

a: in s :r is

Claims

2. Method according to claim 1, in which the extrusion ratio is between 50:1 and 500:1.
3. Die for hydrostatically extruding sections having noncircular cross-section and a core of aluminum and casing of copper the die (10) having a double conical inlet opening (20) and the outer, first conical part (21) having a cone angle ( Alpha ) between 70* and 115* and the inner, second conical part (22) having a cone angle ( Beta ) between 130* and 150* .
4. Die according to claim 3, in which the diameter at the transition between the first and second conical parts (21,11) of the inlet opening (20) is approximately equal to the largest dimension D of the die opening.
5. Die according to claim 3, in which the die opening (23) is rectangular and the diameter at the transition between the first and second conical parts (21, 22) of the inlet opening (20) is approximately equal to the length of the diagonal (D) of the die opening (23).
6. Die according to claim 3, in which the cone angle ( Alpha ) of the first conical part (21) is between 75* and 85* and the cone angle ( Beta ) of the second conical part (22) is between 135* and 145* .