JP2006000890A - Method for melting metallic material in metal molding machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a melting cylinder for melting a metallic material in a metal molding machine, which melting cylinder can improve heating efficiency by heating the metallic material in the melting cylinder from the periphery of a body and a bottom surface. <P>SOLUTION: An ingot having a cylindrical shape (a round rod shape) is used as the metallic material. The metallic material is inserted into the melting cylinder longitudinally provided in a heat holding cylinder, and is partially or completely melted. The melting cylinder is composed of a funnel shape bottom portion connected to the body, an outlet pipe which is located at the center of the bottom and has a diameter smaller than that of the body, an auxiliary heating material laterally arranged in the center of the body in the neighborhood of the bottom portion, and a heating means arranged on the outside peripheries of the body and the outlet pipe. The metallic material is supported by the auxiliary heating material on the bottom portion. The metallic material is heated from the periphery of the body and the bottom surface. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for melting a metal material in a metal molding machine that uses a cylindrical (round bar-shaped) ingot as a metal material, melts the metal material, and injects the metal material into a mold, thereby injection-molding a desired product. It is.

As a forming means for magnesium alloy or the like, a molten metal holding cylinder (heating holding cylinder) is provided with a heating means on the outer periphery of a cylindrical body having a nozzle port at the tip, and a measuring chamber connected to the nozzle port is formed in the tip by reducing the diameter. ) By supplying a granular metal material and melting and accumulating it, or by supplying and accumulating molten metal melted in a melting furnace to a molten metal holding cylinder, and by moving the internal injection plunger back and forth, the molten metal is metered and gold Some are injecting into molds.
Also, as a casting method for metal products, a cylindrical metal material cast by cooling the metal slurry is supplied to the injection device sideways and preheated, then heated to a semi-molten state, stored in a heating chamber, and sucked. Some are injected into the mold by a rod.
Japanese Patent Application No. 2003-24773 JP 2001-252759 A

  Since the granular metal material is easy to oxidize and is light in weight, even if it falls into the molten metal holding cylinder, there are few things that sink into the molten metal and immediately melt, and many of them float on the surface of the molten metal and are long to hot air. Because it is exposed, sludge is likely to occur. The generation of sludge can be suppressed by replacing the metal material with an ingot such as an ingot or a cylindrical body (also referred to as a round bar) that is less oxidized than the granular material.

  However, ingots and columnar bodies cannot be supplied directly to the molten metal holding cylinder, and are supplied after being completely melted by a melting furnace, or preheated by a preheating barrel and then heated to a semi-molten state and stored in a heating chamber. As a result, the metal forming machine becomes large and maintenance work is also required.

  The above problem is to adopt a cylindrical body for the melting furnace of the metal material, and provide the melting cylinder vertically in the heating and holding cylinder equipped with the injection means to heat or melt the columnar metal material while semi-melting or completely melting This can be solved by supplying the heated holding cylinder in a state.

  Such a metal forming machine can be composed of a heating and holding cylinder and a melting cylinder smaller than the melting furnace, so it is not large-sized and easy to maintain, but the metal material is melted by heating means around the melting cylinder. Therefore, the heating efficiency is lower than in the case of a melting furnace in which a metal material is immersed in a molten metal and heated directly, and it takes time to melt.

The inefficiency of heating in this melting cylinder is that heating of the metal bottom is limited to the periphery of the body because it is difficult to heat the bottom and top surfaces of the material, and it takes time until the center reaches the melting temperature.
In addition, the clearance that is set based on the difference between the inner diameter of the melting cylinder and the diameter of the cylindrical metal material also contributes. Until now, the clearance has been set in consideration of the ease of insertion of the metal material, and has been set by determining the inner diameter of the melting cylinder from the diameter of the metal material before heating (during non-thermal expansion). In the setting of the inner diameter, there is a tolerance in the diameter of the metal material and the inner diameter of the melting cylinder, so that the clearance is set larger in consideration of the tolerance.

  The heating efficiency of the metal material by the melting cylinder decreases as the clearance increases. If the clearance is set small to improve heating efficiency and the outer surface of the metal material is brought closer to the inner surface of the melting cylinder, it is often difficult to drop and insert the metal material to the bottom surface of the melting cylinder due to its own weight. Due to the delay in the supply due to the troublesome arrangement, the amount of accumulation in the heating and holding cylinder is reduced, which may hinder the molding operation.

  The present invention has been conceived in order to solve the above-described conventional problems, and the object of the present invention is to solve the problem of the heating efficiency in the melting cylinder by heating from the bottom as well as around the body of the metal material. In addition, the inefficiency of heating around the body can be solved by setting clearance for thermal expansion, and metal in a new metal forming machine that can suppress the generation of sludge by surface processing of metal materials It is to provide a method for melting a material.

  The present invention for the above-described object uses a cylindrical (round bar-shaped) ingot as a metal material, and inserts the metal material into a melting cylinder provided vertically in a heating and holding cylinder, so that the above melting The tube has a funnel-shaped bottom connected to the body, an outflow pipe having a smaller diameter than the body at the center of the bottom, a heating auxiliary material installed in the body adjacent to the bottom, and outside the body and the outflow pipe. It comprises heating means provided in the periphery, the metal material is supported on the bottom by the heating auxiliary material, and the metal material is heated from the periphery and the bottom surface.

  Further, the heating auxiliary material is horizontally installed in the center near the bottom portion in the trunk portion, or a plurality of heating auxiliary materials are arranged transversely in the center near the bottom portion in the trunk portion to support the metal material. The heating means is embedded in the heating auxiliary material, and the metal material is heated by the periphery of the trunk and the heating auxiliary material.

  In the present invention, the clearance c of the body caused by the difference between the body inner diameter D of the melting tube and the diameter d of the metal material does not exceed 1 mm during the thermal expansion of both the melting tube and the metal material, and the metal The melting tube is set in a range where insertion is possible at the time of non-thermal expansion of the material, and the melting cylinder is made of a metal material having a linear expansion coefficient smaller than that of the metal material.

  The metal material used in the present invention is made of a low melting point metal alloy such as a magnesium alloy or an aluminum alloy, and the metal material is heated and melted after cutting and removing impurities formed on the nest and the surface of the material surface layer. That's it.

  In the above configuration, since the bottom surface of the metal material is partially supported by the heating auxiliary material and located on the funnel-shaped bottom portion, the heating auxiliary material is accompanied by the softening of the metal material due to heating from the outer periphery of the body portion. Enters the inside from the bottom due to the load of the metal material. Since the heating auxiliary material is heated by heat transfer from the barrel or by an embedded heating means, the metal material is also heated from within the bottom surface, and combined with the heating from the barrel periphery, the heating efficiency is improved. Compared to the conventional case in which the bottom surface of the metal material is fully supported by the inner bottom surface and the periphery of the cylinder is heated, the melting time can be shortened.

  In addition, in a metal material with a metal structure that exhibits thixotropic properties, the distribution state of the eutectic that melts at the solid-liquid coexisting temperature is non-uniform. Since it is melted, the molten mass does not hinder the outflow to the heated holding cylinder.

  In addition, the insertion clearance is set to a range that does not exceed 1 mm when both the melting cylinder and the metal material are thermally expanded, and can be inserted when the metal material is not thermally expanded. Since it naturally becomes smaller due to the thermal expansion of the metal material after insertion, the heating efficiency around the trunk is improved, and the melting time is shortened in combination with the internal heating by the heating auxiliary material, so it corresponds to the molding cycle It is possible to supply and accumulate metal materials. Furthermore, the surface of the metal material nest and impurities such as oxide adhering to the surface are cut and removed, and the metal material is melted in the melting cylinder, so the generation of sludge due to oxide is reduced, and sludge elimination is included. The period of regular maintenance can be extended, and the production efficiency is improved due to the reduced number of maintenance. In addition, defective molded products due to sludge mixing are significantly reduced and the yield is improved.

  In the figure, reference numeral 1 denotes a metal forming machine, which is composed of a heating and holding cylinder 2 having a nozzle member 22 at the tip of a cylindrical body 21, a melting cylinder 3 of a cylindrical (round bar-shaped) ingot metal material M, and an injection holding cylinder 2. The injection driving device 4 is arranged at the rear.

  The heating and holding cylinder 2 is provided with the melting cylinder 3 at a supply port provided in the middle upper side of the cylinder 21 and heating means 24 by a band heater on the outer periphery of the cylinder. The temperature of the heating and holding cylinder 2 by the heating means 24 is the liquidus temperature and the solidus temperature when the metal material M used for forming is an ingot exhibiting thixotropic properties at a temperature in the solid-liquid coexistence temperature region. In the case of a normal ingot that completely melts, it is set to a temperature equal to or higher than the liquidus temperature.

  The heating and holding cylinder 2 is attached to the support member 23 at the rear end of the cylinder, and is inclined with the injection driving device 4 at an angle of 45 ° with respect to the horizontal plane. The inside of the tip portion positioned downward by this oblique installation is a measuring chamber 25 that communicates with the nozzle opening of the nozzle member 22. An injection plunger 26a of injection means 26 connected to the injection drive device 4 is fitted into the measuring chamber 25 so as to be able to advance and retract. The injection plunger 26a is attached to the tip of a rod 26b inserted from the sealed rear end of the heating and holding cylinder 2 and includes a check valve 26c having a seal ring embedded in the outer peripheral surface thereof so as to be able to advance and retreat around the shaft portion.

  The melting tube 3 is horizontally installed in the center of the funnel-shaped bottom 32 connected to the cylindrical body 31, the outflow pipe 33 having a smaller diameter than the body 31 at the center of the bottom, and the body in the vicinity of the bottom 32. A heating auxiliary member 34 made of a stainless steel round bar and a heating means 35 such as a band heater or an induction heater provided around the outer periphery of the body 31 and the outflow passage 33 are formed. Is attached to open and close. The heating means 35 of the body 31 is divided into a plurality of zones from the lower side to the upper side of the heating auxiliary material 34 so as to be individually temperature-controllable.

  The heating auxiliary material 34 is not limited to one, and is omitted in the figure, but a plurality of heating auxiliary members 34 may be horizontally mounted in parallel with each other, and as shown in FIG. You can lay it horizontally. In this case, the body part 31 is inserted from the upper opening of the body part 31 to the boundary between the body part 31 and the bottom part 32 and latched. When the inside of the bottom portion is positively heated by the heating auxiliary material 34, although not shown, the heating auxiliary material is formed of a tubular body, and a cartridge heater is inserted from the body portion into the body portion. It is preferable to heat separately.

  In the melting cylinder 3 having the above-described configuration, the outflow pipe 33 is inserted into the supply port provided in the cylinder body 21, and the upper portion of the body portion 31 is held by the arm member 27 fixed to the support member 23, and is vertically attached to the heating holding cylinder 2. Is provided. Reference numeral 37 denotes an injection pipe for an inert gas such as argon gas inserted along the outflow pipe 33 up to the molten metal surface L of the heating and holding cylinder 2.

  As the columnar metal material M, a low melting point metal alloy such as a magnesium alloy or an aluminum alloy is used. Further, in use, it is preferable to remove impurities such as surface nests generated during casting and oxides adhering to the surface by cutting. Oxygen in the air entering the surface oxide and nests on the surface tends to generate metal oxide by heating and melting the metal material M to become sludge, which deposits in the heating and holding cylinder 2 and hinders the molding operation. Therefore, the generation of sludge can be reduced by cutting the surface layer to a depth of 1 to 5 mm and removing it.

  The metal material M is inserted into the barrel portion of the melting cylinder 3 heated from the upper opening to a temperature equal to or higher than the liquidus temperature. The metal material M falls in the melting tube 3 by its own weight to the place where the bottom surface is in contact with the heating auxiliary material 34 and is received by the heating auxiliary material 34. In the melting cylinder, the heating means 35 of the barrel 31 receives heat from the periphery of the barrel and the center of the bottom surface where the heating auxiliary material 34 is in contact. Since the metal material M softens when the material temperature exceeds the solidus temperature, the heating auxiliary material 34 receiving the load of the metal material M enters the center portion from the bottom surface. As the heating auxiliary material 34 enters, the softened bottom surface protrudes on both sides of the heating auxiliary material 34 as shown by phantom lines in FIG. Heat. Thereby, the heating of the metal material M is efficiently performed in combination with the heating from the periphery of the trunk.

When the material temperature exceeds the liquidus temperature by the melting cylinder 3, the metal material M is completely melted to become hot water, but in the metal material M in which the metal structure exhibits thixotropic properties at a temperature in the solid-liquid coexistence temperature region, The eutectic distributed therebetween melts at a temperature in the solid-liquid coexistence temperature region before reaching the liquidus temperature, and becomes a semi-molten state due to the liquid phase and the solid phase. Melting preceded by lower undergoing heating from the inside the body and surrounding the central portion, are stored as melt M ₁ of a semi-molten state exhibiting a reduced diameter thixotropic properties outflow pipe 33 into the heating holding cylinder 2 flows from the bottom 32 . When the amount of melting increases, the outflow pipe 33 flows down while accumulating in the bottom portion 32.

In a metallographic structure exhibiting thixotropic properties, the eutectic distribution state is not uniform, so that the molten state is not evenly mixed and may be melted down from the metal material M as a small molten mass. However, since there is a heated funnel-shaped bottom 32 and an outflow pipe 33 below the heating auxiliary material 34, the molten mass melts down on the bottom wall surface and remelts while flowing through the outflow pipe 33 from the bottom wall surface. Will be broken up. Further, when a molten pool is generated in the bottom portion 32, the molten metal sinks into the molten pool and is re-melted. Therefore, even if a molten mass occurs, the melting is performed without any problem, and the outflow pipe 33 is not clogged by the molten mass. Therefore, the melting time can be shortened.
For comparison, the melting time is reduced by about 10 minutes in comparison with the case where the same metal material M is inserted into the flat bottom melting tube described in Patent Document 1 and the bottom surface is fully supported and heated from around the body. .

The semi-molten melt M ₁ accumulated in the heating and holding cylinder 3 flows into the measuring chamber 25 by the backward movement of the injection plunger 26a and is measured, and then injected into a mold (not shown) by the forward movement of the injection plunger 26a. Is done.

  In the melting tube 3, the heating efficiency in the body portion 31 increases as the clearance c generated in the relationship between the body portion inner diameter D and the diameter d of the metal material M decreases. On the contrary, since it becomes difficult to insert the metal material M, it is preferable to set the clearance c for the thermal expansion in consideration of the ease of insertion. The clearance c is set for the diameter d and the body inner diameter D at the time of thermal expansion obtained from the linear expansion coefficient of the material of the metal material M and the metal material employed in the melting cylinder 3, and the heat of both of them. It is set in a range that does not exceed 1 mm during expansion and allows insertion of the cylindrical metal material M. In order to limit the expansion of the clearance c due to thermal expansion, a metal material having an expansion coefficient smaller than the linear expansion coefficient of the metal material is used for the melting cylinder 31.

  With the clearance c set for this thermal expansion, the clearance c between the melting tube 3 that has already been heated and expanded since the metal material M is not thermally expanded when the unheated metal material M is inserted. Is formed larger than that at the time of thermal expansion by the amount of non-thermal expansion. Accordingly, the metal material M can be smoothly inserted even with a clearance c not exceeding 1 mm set for thermal expansion, the heating efficiency in the body 31 is increased, and the melting time of the metal material M is further shortened. Will come to be.

Metal material Magnesium alloy (AZ91D) Linear expansion coefficient 27.0 × 10 ⁻⁶ / K
Shape: cylindrical body, length: 300 mm, mass: 1.5 kg
Melting tube
Material Stainless steel (SUS304) Linear expansion coefficient 16.5 × 10 ^-6 / K
Shape Cylindrical body, bottom depth 30mm, outflow pipe inner diameter 40mm
Heating auxiliary material
Material Stainless steel (SUS304) Linear expansion coefficient 16.5 × 10 ^-6 / K
Shape Round bar Diameter 12mm

Non-thermal expansion Thermal expansion (550 ° C)
Metal material Diameter mm 60.0 60.899
Dissolving cylinder body inner diameter mm 61.3 61.856
Clearance mm 1.3 0.965
Clearance at insertion (61.856-60.0) = 1.856mm
Melting time (600 ° C) About 12 minutes

Comparison of melting time Comparison with non-expansion set clearance 1.8mm However, melting cylinder body diameter 61.8mm, metal material diameter 60.0mm
Melting time (600 ° C) Approx. 20 minutes Result: Clearance at insertion 1.856mm is set clearance at non-expansion 1.8mm
The clearance was 0.056 mm larger than that, but the melting time was short, which was about 8 minutes.

1 is a longitudinal side view of an embodiment of a metal forming machine that can employ a melting method of a metal material according to the present invention. It is a lower vertical side view of a melting cylinder. It is a lower longitudinal front view similarly. It is a plane sectional view of other embodiments which crossed and arranged a plurality of heating auxiliary materials on the bottom in a trunk part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Metal forming machine 2 Heating holding cylinder 3 Melting cylinder 31 Body part 32 Bottom part 33 Outflow pipe 34 Heating auxiliary material 35 Heating means 36 Cover member

Claims (8)

When a cylindrical (round bar-shaped) ingot is used as a metal material, the metal material is inserted into a melting cylinder vertically provided in a heating and holding cylinder, and then semi-molten or completely melted.
The melting tube includes a funnel-shaped bottom continuous to the body, an outflow pipe having a smaller diameter than the body at the center of the bottom, a heating auxiliary material disposed in the body close to the bottom, and the body and the outflow pipe. In a metal forming machine characterized in that the metal material is supported from the periphery and the bottom surface by supporting the metal material on the bottom by the heating auxiliary material. A method for melting metal materials.   2. The method for melting a metal material in a metal forming machine according to claim 1, wherein the heating auxiliary material is installed in the center in the vicinity of the bottom portion in the body portion to support the metal material.   The melting of the metal material in the metal forming machine according to claim 1, wherein a plurality of the heating auxiliary materials are crossed horizontally in the center of the body portion close to the bottom portion to support the metal material. Method.   The method for melting a metal material in a metal forming machine according to any one of claims 1 to 3, wherein a heating means is embedded in the heating auxiliary material, and the metal material is heated by the periphery of the trunk and the heating auxiliary material.   The clearance c of the barrel portion resulting from the difference between the barrel inner diameter D of the melting cylinder and the diameter d of the metal material does not exceed 1 mm during the thermal expansion of both the melting cylinder and the metal material, and the non-heat of the metal material The method for melting a metal material in a metal forming machine according to claim 1, wherein the metal material is set in a range that allows insertion during expansion.   6. The method for melting a metal material in a metal forming machine according to claim 1, wherein the melting cylinder is made of a metal material having a linear expansion coefficient smaller than that of the metal material.   The said metal raw material consists of low melting metal alloys, such as a magnesium alloy and an aluminum alloy, The melting method of the metal raw material in the metal forming machine in any one of Claims 1-6 characterized by the above-mentioned.   The method for melting a metal material in a metal forming machine according to claim 1 or 7, wherein the heat melting of the metal material is carried out after cutting and removing impurities attached to the nest and the surface formed on the material surface layer.

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