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EP0972593A1 - Procédé de coulée sous pression et produits ainsi obtenus - Google Patents

Procédé de coulée sous pression et produits ainsi obtenus Download PDF

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Publication number
EP0972593A1
EP0972593A1 EP99810629A EP99810629A EP0972593A1 EP 0972593 A1 EP0972593 A1 EP 0972593A1 EP 99810629 A EP99810629 A EP 99810629A EP 99810629 A EP99810629 A EP 99810629A EP 0972593 A1 EP0972593 A1 EP 0972593A1
Authority
EP
European Patent Office
Prior art keywords
die
cavity
gas
oxygen
molten metal
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.)
Withdrawn
Application number
EP99810629A
Other languages
German (de)
English (en)
Inventor
Yukio Kuramasu
Takaaki Ikari
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.)
3A Composites International AG
Nippon Light Metal Co Ltd
Original Assignee
Alusuisse Lonza Services Ltd
Alusuisse Technology and Management Ltd
Nippon Light Metal Co Ltd
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 Alusuisse Lonza Services Ltd, Alusuisse Technology and Management Ltd, Nippon Light Metal Co Ltd filed Critical Alusuisse Lonza Services Ltd
Publication of EP0972593A1 publication Critical patent/EP0972593A1/fr
Withdrawn legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D17/00—Pressure die casting or injection die casting, i.e. casting in which the metal is forced into a mould under high pressure
    • B22D17/14—Machines with evacuated die cavity

Definitions

  • the present invention relates to a die-casting method for productions of die-cast products useful not only as structural members but also as functional membere and die-cast products manufactured thereby.
  • molten aluminum or aluminum alloy (hereinafter referred to as "molten metal”) poured into a sleeve is forcibly injected into a cavity of a die-casting mold by a plunger.
  • gas such as air or water vapor are purged from the cavity in response to injection of the molten metal, but some of the gas remain as such in the cavity even after the injection.
  • die-casting molds designed for productions of thin-walled products or products having complicated configurations have portions acting as bottlenecks against metal flow, so that it is difficult to completely remove gas from the cavity.
  • a vacuum die-casting method was proposed.
  • a cavity of a die-casting mold is evacuated before injection of molten metal, so as to remove gas from the cavity.
  • the cavity is held at a degree of vacuum in the range of 200-500 millibar by the evacuation for instance.
  • the degree of vacuum can not be reduced less than said value, due to leakage of air through narrow gaps of dies. Leakage of air also occurs during pouring molten metal into a sleeve.
  • An oxygen die-casting method has been developed in order to eliminate defects in the vacuum die-casting method.
  • a cavity of a die-casting mold is filled with oxygen at a pressure higher than the atmospheric pressure so as to replace gas by oxygen in prior to injection of molten metal. Since oxygen gas fed into the cavity is effused through narrow gaps of dies as well as an injection hole, invasion of atmospheric gas through the narrow gaps or the injection hole can be prohibited.
  • the oxygen gas fed into the cavity is reacted with molten metal, and a reaction product Al 2 O 3 is dispersed as fine particles in a cast product without harmful influences on an obtained die-cast product.
  • Inclusion of the trapped gas also causes blisters in die-cast products, when the die-cast products are heat treated in such as T6 treatment (i.e., solution heating, quenching and then aging) for improvement of mechanical properties. In order to avoid such blisters, most of die-cast products are used without heat treatment.
  • T6 treatment i.e., solution heating, quenching and then aging
  • the present invention is aimed at elimination of such problems as above-mentioned.
  • the objective of the present invention is to remarkably reduce inclusion of gas by combining advantages of both the vacuum die-casting and the oxygen die-casting for die-cast products useful as functional members.
  • a die-casting method is characterized by evacuating a cavity of a die-casting mold to remove gas as well as water vapor from the cavity, followed by blowing oxygen gas into the cavity, and then forcibly injecting molten metal into the cavity.
  • the cavity of the die-casting mold is preferably evacuated to a degree of vacuum not higher than 100 millibar, Pressure of the cavity is then increased to a value higher than the atmospheric pressure by oxygen gas.
  • gas trapped in a cast product is remarkably reduced to a level less than 1cc/100g-Al. Consequently, die-cast products obtained have excellent mechanical properties required for functional members.
  • the die-cast products can be heat treated in T6 treatment without blisters derived from the trapped gas.
  • Fig. 1 a schematic view illustrating a die-casting machine to which the present invention is applied.
  • Fig. 2 is a view for explaining blowing oxygen through a sleeve into a cavity of a die-casting mold.
  • Fig. 3 is a view for explaining pouring an molten metal into a sleeve.
  • a sleeve 3 attached to a cavity 2 is coupled with a die-casting mold 1.
  • the sleeve 3 hae a pouring hole 4, through which molten metal 5 is poured in the sleeve 3.
  • the molten metal 5 in the sleeve 3 is pressed by a tip attached to a plunger rod 6 and forcibly injected into the cavity 2.
  • the molten metal 5 is cooled and solidified to a profile defined by the inner surface of the die-casting mold 1.
  • a die-cast product obtained in this way is taken from the die-casting mold 1 by pushing ejector pins like 8 in the cavity 2 after the die-cast product is cooled.
  • a suction nozzle 11 is attached to the die-casting mold 1 at the proper position such as its parting part, to connect the cavity 2 through the suction nozzle 11 to a vacuum pump.
  • a vacuum pump When the cavity 2 is evacuated through the suction nozzle 11, atmospheric air may probably invade through parts where the ejector pins like 8 are inserted during evacuation. Such air invasion is prohibited by sealing gaps between the ejector pins and the die parts with a sealing agent 13.
  • the pouring hole 4 is closed with the plunger tip 7, so that atmospheric air can not invade into the interior of the sleeve 3 through the pouring hole 4.
  • an oxygen nozzle 14 is opened to the interior of the sleeve 3.
  • the oxygen nozzle 14 is connected through a regulator valve 15 such as a regulator valve to an oxygen supply source.
  • gas such as air and water vapor are excluded from the cavity 2 as well as the interior of the sleeve 3 connected with the cavity 2. Even if the cavity 2 has a complicated configuration, gas are completely excluded from every nook and corner of the cavity 2 by adjusting a suction speed preferably in a range of 500-800 millibar/second.
  • the evacuation is preferably continued 1-2 seconds or so, under the condition that the pouring hole 4 is closed with the plunger tip 7.
  • the evacuation time period is set relatively longer, compared with a conventional vacuum die-casting method whereby the cavity 2 is evacuated for a time period shorter than 1 second without closing the pouring hole 4,
  • the cavity 2 is evacuated to a degree of vacuum preferably below 100 millibar due to the longer evacuation period. Water vapor derived from a parting agent adhering onto the inner surface of the die-casting mold 1 is separated from the inner surface of the die-casting mold and discharged outside.
  • Removal of water vapor is more effectively performed by the evacuation compared with blowing oxygen gas into the cavity, since a gaseous stream flows at a higher speed in the cavity 2.
  • a gaseous stream flows at a higher speed in the cavity 2.
  • the cavity 2 is evacuated to an insufficient degree of vacuum above 100 millibar, a relatively large amount of gas remain in the cavity 2.
  • a large amount of the gas remaining in the cavity 2 are not replaced by oxygen in the following oxygen blowing step but often included in a cast product.
  • oxygen gas is blown through the nozzle 14 into the cavity 2.
  • the oxygen supply is continued preferably 3-4 seconds until gasses and oxygen are effused through the parting part of the die-casting mold 1. Since oxygen gas is blown into the cavity 2 in the state decompressed in the former step, the oxygen gas nows as a high-speed stream to every nook and corner of the cavity 2. As a result, water vapor derived from the parting agent is completely washed off by the supplied oxygen gas.
  • the plunger tip 7 goes back to open the pouring hole 4 during continuation of the oxygen blowing.
  • oxygen gas is effused through the pouring hole 4, as shown in Fig. 2. Effusion of the oxygen gas effectively inhibits invasion of atmospheric air through the pouring hole 4 into the sleeve 3.
  • an molten metal 5 is poured from a ladle 16 into the sleeve 3. Since the oxygen gas is continuously effused during the pouring operation, the effusion of the oxygen gas effectively inhibits inflow of atmospheric air in accompaniment with the molten metal 5.
  • the die-casting mold 1 preferably preheated to 150-200 °C before the pouring step, in order to reduce thermal shock caused by the poured molten metal 5 and improve productivity.
  • the pouring hole 4 is closed with the molten metal 5. Since the closed state does not permit inflow of atmospheric air through the pouring hole 4 into the sleeve, supply of oxygen gas can be stopped.
  • the plunger 6 is forwarded to forcibly inject the molten metal 5 into the cavity 2.
  • the injected molten metal 5 is shaped to a bulk having a profile imitating the inner surface of the die-casting mold 1.
  • the bulk is cooled and solidified to a die-cast products having a predetermined configuration, Hereon, cast defects such as blowholes or porosity caused by inclusion of gas are not generated in the die-cast products, since gas such as air and water vapor are completely excluded from the cavity 2.
  • Oxygen gas remaining in the cavity 2 is reacted with the injected molten metal 5, and the reaction product Al 2 O 3 dispersed as fine products in the die-cast products without causing any harmful influences. Consequently, the die-cast products obtained in this way have excellent properties.
  • a die-casting mold 1 used in this example had a cavity 2 of 150 in diameter and 120 mm in length, a proper water-cooling means was provided at the die-casting mold 1 for partially cooling the die-casting mold 1,
  • a parting agent was sprayed 5 seconds onto an inner surface of the die-casting mold 1.
  • the die-casting mold 1 was then preheated at 180°C and located at a proper position in a die-casting machine.
  • the surrounding around a ejector pin 8 was sealed with a sealing agent 13, and a suction nozzle 11 was attached to a parting part of the die-casting mold 1.
  • the pouring hole 4 was closed with a plunger tip 7, and gas were sucked through the suction nozzle 11 from the cavity 2 and the interior of a sleeve 8 by evacuating the cavity 2 at a suction speed 700 millibar/second.
  • a vacuum gage (not shown) provided at a vacuum source 12 indicated 76 millibar.
  • a regulator valve 15 was opened to blow oxygen gas through an oxygen nozzle 14 into the cavity 2. Oxygen blowing was continued under such pressure condition that oxygen was effused through the parting part of the die-casting mold 1.
  • a die-cast products No.2 obtained by a conventional vacuum die-casting method and a die-cast products No.3 obtained by a conventional oxygen die-casting method from the same aluminum alloy were also subjected to the same Ransley and mechanical tests.
  • the cavity 2 was evacuated 1.5 seconds before injection of the molten metal 5.
  • oxygen die-casting method oxygen gas was blown into the cavity 2, and then the molten metal 6 was injected into the cavity 2 for 6 seconds while blowing oxygen gas.
  • the test results are shown in Table 1. It is noted from Table 1 that an amount of gas such as N 2 and H 2 in the die-cast products No.1 according to the present invention is extremely reduced as compared with values in the die-cast products Nos.2 and 3.
  • the die-cast products No.1 had ductility and tensile strength superior to those values of the die-cast products Nos. 2 and 3.
  • the die-cast products No.1 was improved in mechanical properties by T6 treatment (i.e., heating 3 hours at 480°C, water quenching and then aging 5 hours at 160°C) without occurrence of blisters due to the extremely reduced gaseous impurities.
  • gas such as air and water vapor derived from a parting agent adhering onto an inner surface of a die-casting mold is completely excluded from a cavity of the die-casting mold by oxygen blowing in succession to evacuation. Since an molten metal is injected into the cavity conditioned to the state perfectly free from gas, an obtained die-cast products does not include defects such as blowholes or porosity caused by the gas. Consequently, this new die-casting method is applicable for production of functional members as well as structural members, using advantages of high productivity.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Molds, Cores, And Manufacturing Methods Thereof (AREA)
EP99810629A 1998-07-14 1999-07-13 Procédé de coulée sous pression et produits ainsi obtenus Withdrawn EP0972593A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP19819898 1998-07-14
JP19819898 1998-07-14

Publications (1)

Publication Number Publication Date
EP0972593A1 true EP0972593A1 (fr) 2000-01-19

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP99810629A Withdrawn EP0972593A1 (fr) 1998-07-14 1999-07-13 Procédé de coulée sous pression et produits ainsi obtenus

Country Status (1)

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EP (1) EP0972593A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105414531A (zh) * 2015-12-31 2016-03-23 广东长盈精密技术有限公司 通槽的加工方法
CN113263163A (zh) * 2021-04-28 2021-08-17 深圳大学 一种高效消除固体表面吸附气体的方法及其应用

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1183468A (en) * 1966-06-30 1970-03-04 Int Lead Zinc Res Pore Free Die Casting
JPS558382A (en) * 1978-07-05 1980-01-21 Kawasaki Heavy Ind Ltd Diecast method
JPS5772764A (en) * 1980-10-24 1982-05-07 Fuso Light Alloys Co Ltd Die casting method
WO1990010516A1 (fr) * 1989-03-07 1990-09-20 Aluminum Company Of America Procede, equipement et produit de coulage sous pression
JPH08215822A (ja) * 1995-02-17 1996-08-27 Hitachi Metals Ltd ダイカスト鋳造方法

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1183468A (en) * 1966-06-30 1970-03-04 Int Lead Zinc Res Pore Free Die Casting
JPS558382A (en) * 1978-07-05 1980-01-21 Kawasaki Heavy Ind Ltd Diecast method
JPS5772764A (en) * 1980-10-24 1982-05-07 Fuso Light Alloys Co Ltd Die casting method
WO1990010516A1 (fr) * 1989-03-07 1990-09-20 Aluminum Company Of America Procede, equipement et produit de coulage sous pression
JPH08215822A (ja) * 1995-02-17 1996-08-27 Hitachi Metals Ltd ダイカスト鋳造方法

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 004, no. 033 (M - 003) 21 March 1980 (1980-03-21) *
PATENT ABSTRACTS OF JAPAN vol. 006, no. 157 (M - 150) 18 August 1982 (1982-08-18) *
PATENT ABSTRACTS OF JAPAN vol. 096, no. 012 26 December 1996 (1996-12-26) *

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105414531A (zh) * 2015-12-31 2016-03-23 广东长盈精密技术有限公司 通槽的加工方法
CN105414531B (zh) * 2015-12-31 2019-01-01 广东长盈精密技术有限公司 通槽的加工方法
CN113263163A (zh) * 2021-04-28 2021-08-17 深圳大学 一种高效消除固体表面吸附气体的方法及其应用

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