EP0053510B1 - Procédé d'extrusion - Google Patents

Procédé d'extrusion Download PDF

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Publication number
EP0053510B1
EP0053510B1 EP19810305652 EP81305652A EP0053510B1 EP 0053510 B1 EP0053510 B1 EP 0053510B1 EP 19810305652 EP19810305652 EP 19810305652 EP 81305652 A EP81305652 A EP 81305652A EP 0053510 B1 EP0053510 B1 EP 0053510B1
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EP
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Prior art keywords
extruded
extrusion
air
tubular product
billet
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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
EP19810305652
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German (de)
English (en)
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EP0053510A3 (en
EP0053510A2 (fr
Inventor
Masao Nishihara
Tomiharu Matsushita
Masataka Noguchi
Akira Ohte
Kazuo Arimura
Tetsuo Kimura
Akira Iwai
Nobuo Hayashida
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.)
Kobe Steel Ltd
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Kobe Steel Ltd
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Publication date
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Publication of EP0053510A2 publication Critical patent/EP0053510A2/fr
Publication of EP0053510A3 publication Critical patent/EP0053510A3/en
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Publication of EP0053510B1 publication Critical patent/EP0053510B1/fr
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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
    • B21C23/00—Extruding metal; Impact extrusion
    • B21C23/007—Hydrostatic extrusion
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
    • B21C23/00—Extruding metal; Impact extrusion
    • B21C23/32—Lubrication of metal being extruded or of dies, or the like, e.g. physical state of lubricant, location where lubricant is applied
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
    • B21C43/00—Devices for cleaning metal products combined with or specially adapted for use with machines or apparatus provided for in this subclass

Definitions

  • This invention relates to a method for extruding solid or tubular products using a lubricant, including removing the deposit of carbonised lubricant produced on the surface of each extruded product thereby to improve the quality of the extruded product and facilitate their after treatment.
  • a lubricated extruding process in which a billet precoated with a carbon-base lubricant is loaded into a container after heating the extruded through a die and/or a mandrel or in which the container as well as the die and/or mandrel is coated with a carbon-base lubricant prior to loading a heated billet in to the container for extrusion and the hydrostatic extrusion process in which a hot billet loaded in a container is extruded by the pressure medium applied to the surface of the billet (with the forced lubricating effect of the pressure medium) each have a common problem in that the surfaces of the extruded tubular product are darkened due to depositions of a carbide formed by the extrusion at a high temperature.
  • the carbide deposit on the extruded product not only lowers its value but also can cause corrosion when the tubular product is used as a condenser tube of a heat exchanger or the like.
  • air is also fed to an outer surface of the extruded tubular product at a combustion improver feed zone located downstream of the extrusion die to burn off the carbide of said lubricant deposited on the outer surface of said extruded tubular product, and water is fed to the outer surface of the extruded tubular product at a water cooling zone located downstream of said combustion improver feed zone to suppress oxidation on the outer surface and suppress grain growth of said extruded tubular product.
  • the feeding rate of air fed to the outer surface of the extruded tubular product is controlled to satisfy the following conditions:
  • FIGS. 1 and 2 illustrate a conventional hydrostatic extrusion and a similar hydrostatic extrusion incorporating the method of the present invention, respectively.
  • a hot hollow billet 3 which is heated to a high temperature of 500°C or more is loaded into a container 1 and a pressure medium 4 such as a commercially available non-soap type grease, liquid polymer or the like is spread on a mandrel 6 which projects from the front end of a press stem 7 through a seal piston 5, a pressure medium 4 surrounding hollow billet 3 which is extruded by displacement of the stem 7 into a tubular product 3a through a space defined between the mandrel 6 and a press die 2, as shown in Figure 1.
  • a pressure medium 4 such as a commercially available non-soap type grease, liquid polymer or the like
  • the pressure medium 4 sticks to the extruded billet and forms carbide deposits on the inner and outer surfaces of the tubular product 3a which is extruded at a high temperature.
  • the hollow billet 3 is precoated with a carbon-base lubricant and heated before charging into the container 1, and then extruded into a tubular form 3a through the mandrel 6 and die 2.
  • a heated hollow billet 3 is charged into the container 1 after precoating the container 1, mandrel 6 and die 2 with carbon-base lubricant and similarly extruded into a tubular form 3a through the mandrel 6 and die 2.
  • carbide of the lubricant is deposited onto the surfaces of the extruded tubular product in a manner similar to the hydrostatic extrusion.
  • the carbonized lubricant or pressure medium deposit lowers the quality of the product and will cause corrosive degradation. Thus as mentioned before the deposit should be removed completely.
  • FIG. 1 depicts a hot lubricated extrusion incorporating the method of the present invention, in which a container 1, die 2, hollow billet 3, pressure medium 4, seal piston 5, mandrel 6 and stem 7 are arranged substantially in the same manner as in Figure 1.
  • an axial bore 8 is provided centrally through the mandrel 6 to feed a combustion improver or a mixture of a combustion improver and water as shown in Figure 2.
  • a combustion improver or a mixture of a combustion improver and water to the bore 8
  • bores 9 and 16 are provided through the stem 7 in communication with the bore 8.
  • the stem 7 holds the mandrel 6 and is held in a crosshead 15 which is movable back and forth together with the stem 7.
  • air is referred to as an example of a combustion improver which is fed to a supply passage 17 alone through a valve 14 or together with water which is fed from a pump 11 through a valve 12.
  • combustion improver in the present invention, it is preferred to employ a combustion improver in the form of a gas in view of the ease of control of the feeding of the improver continuously from outside into the extruded tubular product through the axial through bores in the mandrel 6 and stem 7 or other components of the press. It is particularly preferred to use atmospheric air which is easily available and advantageous from the standpoint of cost and safety.
  • combustion improver alone can attain the purpose of the present invention
  • its combined use with water serves to cool the mandrel by forming a mist when the combustion improver is in the form of a gas like air.
  • the combustion improver is fed in a mist form to cool off the tube, the carbide deposits on the inner surface of the tubular product are burned off immediately upon extrusion thereof so that the temperature drop of the tube does not hinder the removal of the carbide.
  • the required air in compressed form is fed from an air compressor 13 into the extruded tube through the air supply passage 17 and axial bores 16, 9 and 8.
  • the air is slightly heated during its passage through the mandrel 6, by absorbing heat from the latter, to a level higher than 50°C, while the hollow billet 3 is heated to 500 to 1150°C prior to loading it into the container 1 and extruding it at a stem speed of 40 to 50 mm/sec.
  • the air which is supplied in this manner reacts with the lubricant or pressure medium 4 which is extruded with the tubular product 3a through the gap between the mandrel 6 and billet 3, to completely burn off the lubricant or pressure medium by virtue of the heat of the extruded tubular product 3. If the tubular product is extruded at a low temperature, it is necessary to select a suitable lubricant or pressure medium which will be burnt off at the lower temperature.
  • a billet heated similarly to a temperature above 500°C may be charged into the container and extruded by means of a commercially available pressure medium such as a non-soap type grease containing an inorganic compound as a tackifier in a mineral oil or a viscous liquid polymer.
  • a commercially available pressure medium such as a non-soap type grease containing an inorganic compound as a tackifier in a mineral oil or a viscous liquid polymer.
  • a viscous liquid polymer it is preferred to employ a viscous liquid polymer as a pressure medium for hydrostatic extrusion.
  • the complete burn-off of the lubricant or pressure medium by air or another combustion improver which is fed into the extruded tubular product through the axial bore 8 in the mandrel in accordance with the method of the present invention can be applied to billets in a very wide temperature range.
  • the combustion improver is in the form of a gas like air as in the above-described embodiment, it should be fed at such a rate that the oxygen content in the gas is sufficient for completely burning off the lubricant or pressure medium which is extruded along with the billet 3 through the gap between the mandrel 6 and billet 3.
  • the extruded tubular product 3a may bear on its inner surface closely deposited amorphous carbon particles to a thickness of 0.3 to 0.5 microns. Therefore, it is sufficient to feed oxygen in sufficient quantity to completely burn off the 0.5 micron thick amorphous carbon deposit but desirably more than the minimum amount of oxygen should be supplied for reliable and stable operation.
  • the combustion improver is used in a mist form
  • water in a reservoir or tank 10 is fed by a pump 11 through a valve 12 as shown in Figure 2 and mixed under increased pressure with the compressed air from the air compressor 13, the mist being fed to the axial bore 8 of the mandrel 6 through the supply passage 17 and axial bores 16 and 9.
  • the misty combustion improver gas is fed also into the tubular product being extruded as mentioned hereinbefore but its acceleration of the cooling effect on the extruded tube causes no problems since the carbide on the inner surfaces of the extrudate is burned off immediately upon extrusion by the die 2 and mandrel 6.
  • Copper-base materials above all, pure copper and cupro-nickel are very susceptible to oxidation although brass is relatively immune from oxidation.
  • oxygen which is fed in an excess amount remains in the tube after complete combustion of the carbide deposits without reacting with the metal or is released from the front end of the extruded tube 3a, so that the inner surfaces retain a clean brass colour.
  • pure copper or cupro-nickel use of excess oxygen supply causes production of an oxide film on the base metal by reaction with the residual oxygen which lingers in the tube after complete combustion of the carbide deposits. This also occurs in brass if oxygen is supplied in an extremely excessive amount.
  • the existence of a slight oxidation film or a thin drawable film of Cu 2 0 is permissible, which however turns into CuO if oxygen is supplied in an excess amount.
  • the production of the oxidation film of CuO causes deteriorations in the surface properties in the drawing stage, and it is difficult to remove it by reduction by bright annealing which is usually effected subsequent to the drawing. Therefore, the feed rate of the combustion improver should be so controlled as not to produce an oxidation film of CuO.
  • the present invention has succeeded in establishing effective and reliable principles as a result of repeated experiments and studies. More particularly, the carbide (of the lubricant or pressure medium) which deposits on the inner surfaces of the tubular extrudate 3a through the gap between the mandrel 6 and billet 3 is complete burned off in the region to which the combustion improver such as oxygen and air is blown in from the inner end of the axial bore 8 of the mandrel 6.
  • the combustion improver should not remain, even in a small amount in the tube after it has passed from the region where combustion takes place if a sound tubular product 3a is to be manufactured in which the inner surfaces are completely free of combustible carbide and in which the base metal is not oxidised.
  • the combustion improver still remains in the tube which has passed the combustion region and reacts with the base metal to form an objectionable oxidation film, the oxidation reaction terminating when the combustion improver becomes scarce because of the formation of the oxidation film.
  • the feed rate Q of the combustion improver for good extrusion is commonly in the range defined below. It has been experimentally confirmed that this method is effective for the extrusion of a billet of copper or a copper alloy using air as the combustion improver.
  • the feed of the combustion improver should be cut off when the extruding speed becomes zero upon completion of extrusion of the tubular product 3a. If the feed is cut off with a time delay at the time of completion of extrusion localized oxidation takes place due to the presence of excess oxygen as mentioned before and the oxidized area extends toward the front end of the tubular product 3a. However, a slight time delay should desirably be allowed in the actual operation.
  • the time point for stopping the feed of combustion improver if it is cut off before the extrusion is complete, the combustion of the carbide in the extruded tubular product 3a becomes incomplete and deposits of combustible carbide appear at the rear end of the extruded product.
  • the feed of the combustion improver is stopped after a delay, an oxidation film is formed at the rear end of the product to a conspicuous degree due to the supply of excess oxygen.
  • the feed of the combustion improver should be controlled in a suitable time range which does not lower the production yield, and in actual operations should suitably be stopped within a time range from one second before to five seconds after the termination of the extrusion of the tubular product 3a.
  • the billet may be extruded under a condition in which a slight oxidation film is formed on the inner surface of the extruded tube by residual oxygen, and reducing the oxidation film by feeding through the mandrel 6 a DX gas (2.85% CO, 1.99% H, 11.9% CO and the balance of N) in the succeeding cooling phase of the tubular product 3a. Since the DX gas is fed after termination of the extrusion, it is necessary to maintain the tubular product 3a in a temperature range suitable for the reduction reaction.
  • the residual gas in the extruded tube may be replaced by a non-oxidative gas such as an inert gas or reduction gas to improve the quality of the product.
  • Tables 1 to 3 illustrate the results of more specific extrusion experiments according to the method of the present invention in comparison with corresponding conventional methods.
  • the subject of the experiment is captioned on each table and in Tables 2 and 3 the 'h value' is defined as:
  • deposited carbonized lubricant on the outer surface of extruded material can also be removed by feeding combustion improver to the outer surface of the extruded material which leaves the extrusion die, and bringing coolant liquid into contact with the outer surface of the material after the carbonized lubricant is burned off.
  • carbonized lubricant remaining on the outer surface can be completely removed, oxidation film formation can be prevented, and crystal grain growth of the extruded product can also be suppressed.
  • the thickness of the carbonized lubricant retained on the outer surface of the extruded tube is at most 1.4 um.
  • the optimum amount of combustion improver is fed to the extruded material while the material is still hot. If the amount of combustion improver is insufficient, carbide will remain on the outer surface, but if the amount of combustion improver is too much, an oxidized film is formed on the outer surface of the extruded material.
  • FIG. 3 is a diagram of an apparatus for carrying out the method of the invention.
  • An air feeding zone A is provided downstream of the extrusion die 2 so that air is brought into contact with the outer circumference of the extruded material.
  • a water cooling zone w is provided downstream of said air feeding zone A, so as to prevent oxidation and to suppress crystal grain growth of the extruded material.
  • the amount of air feed should be proportional to the surface area of the extruded material that passes through the combustion zone (air feeding zone) per unit time period. Therefore, the air feeding rate q(cm/m) can be obtained by the following formula: where K is a constant factor in cm, D is the outer diameter of extruded material (cm), R is the extrusion ratio, and V is the extrusion speed (stem speed) (cm/sec.)
  • Figure 5 shows the relationship between the period of time for the material to pass through the air feeding zone and the amount of air fed.
  • the desired period for the material to pass through the air feeding zone varies depending on the amount of air fed, but if the amount of air fed is 140x10 3 cc/m, the period shall preferably be shorter than 0.13 second. If the amount of air fed is 70x10 3 cc/m, the period shall preferably be shorter than 0.35 second. Generally as the amount of air fed becomes less, the period should be longer, but then the extruded material will cool resulting in coarse grains within the extruded material.
  • Crystal grains of extruded cupro-nickel tube do not grow even if the tube is slowly cooled in the atmosphere.
  • aluminium brass crystal grains grow rapidly and the surface gets rough when it is drawn.
  • the length of air feeding zone is considered for aluminium brass.
  • the extrusion conditions are:
  • the period of time for the material to pass through the air feeding zone is 0.41 second, which is a sufficient period for the carbonised lubricant to completely burn off judging from Figure 5.
  • the outer surface of the extruded material can be cleared and grain growth can be suppressed by the provision of an air feeding zone which is followed by a water cooling zone at the downstream side of a hot hydrostatic extrusion die.
  • the present invention is particularly excellent at completely removing the combustible carbide of the lubricant or pressure medium which tends to deposit on the surfaces of the solid or tubular product, permitting production of solid or tubular products with clean and defect-free surfaces in a simple manner.
  • the combustion improver which may mainly consist of a combustion improver gas such as oxygen and air or a mixture of a combustion improver and water is fed to the initial billet extruding point of the die and/or mandrel to cause complete combustion of the combustible carbide under the high extruding temperature.
  • the outer surface of the extruded material can be cleaned by removing carbonized lubricant by means of applying combustion improver. Oxidation and undesirable grain growth of the extruded material can be prevented by bringing coolant into direct contact with the outer surface.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Extrusion Of Metal (AREA)

Claims (3)

1. Un procédé d'extrusion d'un métal avec lubrification à chaud dans lequel une billette de cuivre ou d'un alliage de cuivre est extrudée pour donner une forme tubulaire au moyen d'une filière et/ou d'un mandrin, avec un lubrifiant organique interposé entre la billette et la filière et/ou le mandrin, cette méthode consistant à introduire de l'air ou un mélange d'air et d'eau dans le produit tubulaire extrudé dans un passage d'introduction dans le mandrin pour éliminer par combustion le carbure provenant du lubrifiant déposé sur la surface interne du produit tubulaire extrudé, cet air étant introduit à un débit de Q compris dans l'intervalle K1.d.R.V.≦Q≦ K2.d.R.V. (où Ki=0,00018 cm et Kz=0,0142 cm, d est le diamètre interne du produit en cm, R est le rapport d'extrusion et V est la vitesse d'extrusion de la billette en cm/s). et à arrêter l'introduction de l'air ou du mélange d'air et d'eau après achèvement de l'extrusion.
2. Un procédé tel que revendiqué dans la revendication 1, caractérisée en ce que l'on. envoie aussi de l'air sur la surface externe du produit tubulaire extrudé dans une zone d'introduction de promoteur de combustion située en aval de la filière d'extrusion pour éliminer par combustion le carbure provenant du lubrifiant déposé sur la surface externe du produit tubulaire extrudé et on envoie de l'eau sur la surface externe du produit tubulaire extrudé dans une zone de refroidissement par l'eau située en aval de la zone d'introduction du promoteur de combustion pour supprimer l'oxydation de la surface externe et supprimer la croissance du grain du produit tubulaire extrudé.
3. Un procédé tel que revendiqué dans la revendication 2, caractérisé en ce que le débit d'air envoyé sur la surface externe du produit tubulaire extrudé soit régulé de façon à satisfaire aux conditions suivantes:
Figure imgb0009
où Kg=0,0003 cm et K4=0,0007 cm, q est le débit d'introduction d'air (cm3/mn), D est le diamètre extérieur du produit tubulaire extrudé (cm), R est le rapport d'extrusion, et V est la vitesse d'extrusion (vitesse de la tige) (cm/s).
EP19810305652 1980-11-29 1981-11-30 Procédé d'extrusion Expired EP0053510B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP16991880A JPS5791822A (en) 1980-11-29 1980-11-29 High-temperature lubrication extrusion method for tubular product
JP169918/80 1980-11-29

Publications (3)

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EP0053510A2 EP0053510A2 (fr) 1982-06-09
EP0053510A3 EP0053510A3 (en) 1982-07-14
EP0053510B1 true EP0053510B1 (fr) 1985-05-22

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EP19810305652 Expired EP0053510B1 (fr) 1980-11-29 1981-11-30 Procédé d'extrusion

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EP (1) EP0053510B1 (fr)
JP (1) JPS5791822A (fr)
CA (1) CA1191480A (fr)
DE (1) DE3170645D1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6708752B2 (en) 2001-04-19 2004-03-23 Alcoa Inc. Injector for molten metal supply system
US6712126B2 (en) 2001-04-19 2004-03-30 Alcoa, Inc. Continuous pressure molten metal supply system and method

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5919769B2 (ja) * 1981-11-04 1984-05-08 昭和アルミニウム株式会社 真空用アルミニウム製中空押出形材の製造法
WO2002085560A1 (fr) * 2001-04-19 2002-10-31 Alcoa Inc. Injecteur pour systeme d'alimentation en metal en fusion
ITPD20010302A1 (it) 2001-12-28 2003-06-28 Bbs Riva Spa Dispositivo idraulico per pompare e / p intercettare metallo allo stato fuso
US7934627B2 (en) 2005-10-13 2011-05-03 Alcoa Inc. Apparatus and method for high pressure extrusion with molten aluminum

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1182193B (de) * 1960-04-07 1964-11-26 Hydraulik Gmbh Kuehlvorrichtung an Metallrohrpressen
DE1602309A1 (de) * 1967-05-12 1970-04-23 Mannesmann Ag Verfahren und Vorrichtung zum Entfernen von Schmiermittelbelaegen von den Oberflaechen stranggepresster Gegenstaende
DE2739800A1 (de) * 1977-09-03 1979-03-22 Schloemann Siemag Ag Verfahren und einrichtung zur herstellung von kupferrohren, insbesondere mittels indirekt-metallstrangpressen

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6708752B2 (en) 2001-04-19 2004-03-23 Alcoa Inc. Injector for molten metal supply system
US6712126B2 (en) 2001-04-19 2004-03-30 Alcoa, Inc. Continuous pressure molten metal supply system and method
US6712125B2 (en) 2001-04-19 2004-03-30 Alcoa Inc. Continuous pressure molten metal supply system and method for forming continuous metal articles

Also Published As

Publication number Publication date
CA1191480A (fr) 1985-08-06
JPS5791822A (en) 1982-06-08
EP0053510A3 (en) 1982-07-14
JPS6144563B2 (fr) 1986-10-03
DE3170645D1 (en) 1985-06-27
EP0053510A2 (fr) 1982-06-09

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