CA1089411A - High temperature hydrostatic extrusion of an aluminium containing billet using polyethylene wax as lubricant - Google Patents

High temperature hydrostatic extrusion of an aluminium containing billet using polyethylene wax as lubricant

Info

Publication number
CA1089411A
CA1089411A CA316,827A CA316827A CA1089411A CA 1089411 A CA1089411 A CA 1089411A CA 316827 A CA316827 A CA 316827A CA 1089411 A CA1089411 A CA 1089411A
Authority
CA
Canada
Prior art keywords
billet
polyethylene wax
aluminum
weight
lubricant
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
CA316,827A
Other languages
French (fr)
Inventor
Martin Burstrom
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
ABB Norden Holding AB
Original Assignee
ASEA AB
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by ASEA AB filed Critical ASEA AB
Application granted granted Critical
Publication of CA1089411A publication Critical patent/CA1089411A/en
Expired legal-status Critical Current

Links

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B21MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21CMANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
    • B21C23/00Extruding metal; Impact extrusion
    • B21C23/007Hydrostatic extrusion
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B21MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21CMANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
    • B21C23/00Extruding metal; Impact extrusion
    • B21C23/32Lubrication of metal being extruded or of dies, or the like, e.g. physical state of lubricant, location where lubricant is applied

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Lubricants (AREA)
  • Extrusion Of Metal (AREA)
  • Forging (AREA)
  • Metal Extraction Processes (AREA)
  • Laminated Bodies (AREA)

Abstract

APPLICATION

OF

MARTIN BURSTR?M

FOR

HIGH TEMPERATURE HYDROSTATIC EXTRUSION OF AN ALUMINUM-CONTAINING
BILLET USING POLYETHYLENE WAX AS LUBRICANT

ABSTRACT OF THE DISCLOSURE

Surface imperfections on the surface of an extrusion-formed aluminum or aluminum alloy product are reduced by applying a coating of polyethylene wax to the surface of the billet prior to heating and subsequent hydrostatic extrusion through the die opening of a forming tool.

Description

~0E39411 BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
The present inven-tion relates to a ~lethod for extruding I metallic objects through a die, and more specifically to a ¦ method which provides for an improved surface quality of the produc-t when extruded at elevated temperatures.
DESCRIPTION OF THE PRIOR ART
In the hydrostatic extrusion of metallic billets in extrusion presses, the billet is surrounded by a pressure medium, I and this pressure medium causes the billet to be pressed out through the clie portion of the press in order to form a rod, tube or wireshaped product. If the extrusion is carried out at an elevated temperature, e.g., if the billets are preheated ¦ pri~r to extrusion, a lubricant layer i5 normally applied to to the surface of the billet to aid in the extrusion processing ~ and to reduce the surface imperfections in the extruded product ¦ caused by contact with the die opening. Typical lubricants applied to billets in such circumstances are stearatesO such Il as zinc stearate and sodium stearate, highly viscous mineral I oil, and a finely divided soft inoryanic material such as ¦ chalk, talcum, graphite, molybdenum disulphide and soft metals.
When the billet extrusion is carried out at room temperature, i.e., the billet is not preheated prior to extrusion, processing lubricants can also be'applied to the ¦ surface of ~he billet so a~ to maintain a lubricating film ' . :~
- , ~
-1 ' between the billet and the die (or forming tool3 during the extrusion step. Indeed, beeswax has been previously used in such circumstances as a lubricant when the billets are made of ,1 aluminum or aluminum alloys. However~ i-t has been recognized ~I that beeswax cannot be used as a lubricant when the billet is extruded at an elevated temperature.
It is an object of the present invention to provide a ¦ method for extruding metallic billets, specifically billets made Il of aluminum or aluminum alloys, at elevated temperatures through ~i a die opening wherein the surface of the extruded product has i less surface imperfections due to cladding and galling created ¦as the billet passes through the die opening than has been previously obtainable.
~I SUMMARY OF THE INVENTION l I
¦1 According to the present invention, extruded aluminum or aluminum alloy products are formed which have reduced surface ¦imperfections as a result of the application to the surfaces of-Ithe aluminum or aluminum alloy billets, prior to ¦¦extrusion, of a lubricating layer o polyethylene wax.
¦I The inventive technique has particular application to extrusion processes wherein the billets pass through dies ¦
~(forming tools) which result in the cross-sections of the billets being reduced by more than 50 to I. ¦
¦¦ Thus, in accordance with one embodiment of the present ¦ invention, thè aluminum or aluminum alloy billet is coated with . ' ' .
. , . :

~ - 2 - ~ ~
- . : . , ~

I i the polyethylene wax lubricant, heated to a temperature of ~bove , 130 C., and then hydrostatically pressea through the die opening !l in a suitable forming tool. At this elevated temperature, the polyethylene waxes will indeed melt; however, and most surpris-5 1¦ ingly, it has been found that they will retain their ability tolubricate the passage of the billet through the die opening in ' the forming tool.
In accordance with another embodiment of the present ~ invention, the polyethylene wax-coated billet is heated to at least 200 C. prior to passage thr.ough the die opening in the forming tool. The advantage of this embodiment resides in the fact that the required pressure needed to press the billet through the die opening-in the forming tool is reduced and the cross sectional reduction-in the size o~ the billet can be increased.
1l It has been found that the polyethylene.waxes used as lubricants ¦ in accordance with the present invention ~unction quite well at above 200 C., and even up to 400 C., which temperatures are far above the melting points o~ available polyethylene waxes.
l The polyethylene waxes used as the lu~ricating agents ¦ in accordance with the present invention comprise polyethylenes having molecular weights.between 2,000 and 15,000. Particularly, preferred polyethylene waxes include polyethylenes having molecula ¦ weights exceeding 5,000. Minor~amounts of straight and branched ~;
~ chain hydrocarbons having molecular weights of up to 1,500 ..
I may be optionally added o the poly-thylenes to form the wax.

, I

l . - 3 - .

The aluminum alloys which can be used to form the billets in the ¦1 method of the invention con~ist~ of at lea~t 855~ by weight of aluminium Il and at mo~t 15% by wei~ht of alloyin~ material~. For example, one .
Il suitable alloy may comprise 5,5% by weight copper, 0.5% by 5, weight lead, 0.5% by weight bismuth, with the remainder being aluminum (AA 2011 ) ~ Another suitable alloy may comprise 4O5%
~¦ by weight copper, 1.5% by weight magnesium, 0.6% by weight ¦ manganese with the remainder being aluminum (AA 2024). Another ! suitable alloy may comprise 5.2% by weight of magnesium, 0.1% by I weight of magnanese, 0.1% by weight chromium, with the remainder being aluminum (AA 5056). other suitable alloys may comprise the following constituents as follows: 0.7% by weight magnesium, 0.4% by weight silicon, with the remainder being aluminum (AA
¦l 6063); 1.0% by weight magnesium, 0.6% by weight silicon, 0.25%
¦1l. by weight copper, 0~25% by weight chromium, with the remainder ¦
being aluminum (AA 6061); 5.5% by we.ight zinc, 2~5% by weight magnesium, 1~5% by weight copper, 0.3% by weight chromium, I with the remainder being aluminum (AA 7075); and 6.8% by weight ¦I zinc, 2.7% by weight magnesium, 2~0% by weight copper, 0.3% by ~I weight chromium, with the remainder being aluminum (AA 7178).
¦, The polyethylene wax can be applied to the surface of the billet by first dissolving the polyethylene wax in a ¦~ suitable solvent (e.g. white spirit) and then either penciL
Il coating or spraying tbe solution onto the billet which has been warmed to about 100- C. or, alternati~cly, by ir~ersing =he - ,'~
Il .' , '11 . .
Il - 4 - ~ i~
. _._ _ _ . ... _ _ . . . . . . .

, warm~d billet in solution containing the polye-thylene. Once the ~
~I solvent has been allowed to evaporate by equilibriation with the ¦
surrounding atmosphere, a suitable thin film o the polyethylene ~I wax will be leEt on the billet surface.
, The novel features of the presen-t invention will now be explained and better understood by reference to the accompanying Il Figure and the following discussion.
I DESCRIPTION OF THE FIGURE
...
The Figure shows a cross-sectional side view of an extrusion device, supported on a suitable press table and containing an extrudable meetallic billet, in accordance with the present invention.
DESCRIPTIO~ OF THE PREFERRED EMBODIMENTS

I As shown in the Figure, on-top of a press table 1 is 15 l¦ positioned a cylinder 3 within which an operating piston 2 is ! positioned or reclprocating movement. -These structures are all ¦
- ¦¦ located within a hydraulic press (no-t shown) which includes a cylinder with-a piston or operating piston 2. Resting on the -~ top of table 1 and inside of cylinder 3 is a die support 5 1~l with-central hQle 12, which itself supports a die 4 with opening 11. The table 1 has a hole 13 which has a larger diameter than hole 12, and which is positioned directly beneath hole 12 !
Between piston 2 and die 4 is a mandrel 6 having a conical upper Il portion 7, a mandrel holder plate 8 with a recess9 or the l~ mandrel (the top of the recess 9 being shaped in a corresponding .~
.,' - ~ . ., ~~l, ~ 5 ~ I
~- .

fashion to the shape of upper conlcal portion 7 of the mandrel) l~ and a support tube 10 for the mandrel holder plate. The support ~I tube 10 is supported by the die 4 and functions to hold the ¦¦ mandrel 6 in its correct position. ;;
¦i In operation, a billet 14 oE aluminum or an aluminum ¦ alloy (for example an alloy containing 5.5% by weight of zinc, ¦ 2.5% by weight magnesium, 1.5% by weight copper, 0.3/O by weight chromium, with the remainder aluminum (AA 7075))is inserted into ~ ;
l the cylinder (the billet having a cylindrical shape and having an axiai hole lS therethrough for the mandrel 6). The mandrel and mandrel holder plate is then properly inserted into the - ~
cylinder 3. A pressure medium 16, such as castor oil, lS ~ :
poured into the cylinder such that it fills the space above and then, by flow through holes 17, below the mandrel holder plate 8. ;;~
Piston 2 i5 p~sitioned to extend into cylinder 3 and by movement ;
downwardly causes pressure build up on billet 14. In this regard, the pressure medium is retained within~the cylinder aue to the use of seals 20 and 21 which are respectively arranged between the die support and the cylinder, and between the piston and the cylinder. Once a suitable pressure build up is ~ achieved, i.e., between 500 and l500 MPa, and due to the fact ;
i , .
¦ that the lower portion 18 oE billet 14 is shaped in a corres-¦ ponding fashion to the inlet cone 19 of the die 4, the billet ¦I will be extruded through opening 11 in die 4.

: -L~

` Before the billet 14 is placed in the extrusion device, I however, it is coated with a polyethylene wax and heated to at least 200 C. in accordance with the present inven-tion.
I More specifically, the billet 14 can be first cleaned by 1~ both washing and trichloroe-thylene and then blasting with steel shot (e.g., steel shot havlng a grain size of 0.7-0,8 mm);
heated to about 100 c.,-pencil coated with a hot (120 C.) solu-tion of polyethylene wax solution (e.g., solution comprising jj 15 parts by weight of a polyethylene wax having a melting point of between 120 C. and 130 C. and a molecular weight of the major part thereof of 9,000 (and identified as PA l90 by Fabwerke Hoechst AG) and 85 parts by weight white spirit solvent);l ¦ allowed to equilibriate with the surrounding atmosphere such that¦
' the white spirit solvent evaporates, leaving a thin film of I polyethylene wax on the surface o~ the billet; and heated to a ¦ temperature of240 C, I -Actually, as the billet passes through the nozzle in the ¦¦ die, the billet temperature will rise to about 350-600 C.
Of course the billet is to be extruded into the shape of 20 1l rod or wireshaped product according to the invention, the design ;
¦ of the press is not quite the same as shown in the Figure; it is ¦1 simpler since neither the mandrel or mandrel holder plate is Il needed.
. ~ ' - ' , . ':

11 , ' ' . ` '' : ~
1 - 7 _ _ . . , . ,; ,,, ,~ ,, .... ~ .. .

While there has been shown and described what is ¦ considered to be the preferred embodiment of the present .
invention, it will be obvious to those skilled in the art that ~ various changes and modifications may be made therein without ;-5 1l departing from the invention as defined in the appended claims.

1.1 ` ' ,.. . ` . ':' ' ~ ~

11 ' ' . . - ~
~I ' ` ' :

.: .

Claims (6)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:
1. In a method of hydrostatically extruding an aluminum-containing billet wherein the billet is first preheated to a temperature of above 130° C. and is then pressed through the die opening of a forming tool by a liquid pressure medium, the improvement wherein said billet, prior to extrusion, is coated with a lubricant consisting essentially of polyethylene wax which is melted prior to extrusion.
2. The method of claim 1 wherein said polyethylene wax consists of polyethylenes having molecular weights between 2,000 and 15,000.
3. The method of claim 2 wherein said polyethylenes have a molecular weight of at least 5,000.
4. The method of claim 1 wherein said polyethylene wax lubricant is coated onto said billet by pencilling a solution containing said polyethylene wax and a white spirit solvent onto said billet and thereafter allowing the solvent to evaporate.
5. The method of claim 1, wherein said polyethylene wax lubricant is coated onto said billet by immersing said billet in a solution containing said polyethylene wax and a white spirit solvent, removing said billet from the solution, and thereafter allowing the solvent to evaporate.
6. The method of Claim 1 wherein said aluminum-containing billet is formed with at least 85% by weight of aluminium and at most 15% by weight of alloying materials.
CA316,827A 1977-11-28 1978-11-24 High temperature hydrostatic extrusion of an aluminium containing billet using polyethylene wax as lubricant Expired CA1089411A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE7713412-0 1977-11-28
SE7713412A SE409120B (en) 1977-11-28 1977-11-28 USE OF A POLYETHEN WAX AS LUBRICANT IN HYDROSTATIC EXTRACTION OF ALUMINUM OR ALUMINUM ALLOY

Publications (1)

Publication Number Publication Date
CA1089411A true CA1089411A (en) 1980-11-11

Family

ID=20333012

Family Applications (1)

Application Number Title Priority Date Filing Date
CA316,827A Expired CA1089411A (en) 1977-11-28 1978-11-24 High temperature hydrostatic extrusion of an aluminium containing billet using polyethylene wax as lubricant

Country Status (6)

Country Link
JP (1) JPS5483663A (en)
CA (1) CA1089411A (en)
DE (1) DE2849867A1 (en)
FR (1) FR2409799A1 (en)
GB (1) GB2010158B (en)
SE (1) SE409120B (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5191779A (en) * 1989-12-06 1993-03-09 Toyo Seikan Kaisha, Ltd. Method of producing a metallic can using a saturated branched chain containing hydrocarbon lubricant
CN103978061B (en) * 2014-05-14 2015-12-09 上海汽车变速器有限公司 Elongated heavy wall variable cross-section endoporus tungsten alloys device and method

Also Published As

Publication number Publication date
GB2010158A (en) 1979-06-27
GB2010158B (en) 1982-02-10
FR2409799A1 (en) 1979-06-22
DE2849867A1 (en) 1979-05-31
JPS5483663A (en) 1979-07-03
SE7713412L (en) 1979-05-29
SE409120B (en) 1979-07-30

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