JP2004237309A - Nozzle member for light alloy injection-molding machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a nozzle member for light alloy injection-molding machine which has excellent corrosion resistance and inexpensive, prevents the damage caused by galling and can be regenerated profitably. <P>SOLUTION: In the nozzle member used for the injection-molding machine for injection-molding the molten light alloy, a sleeve composed of a cobalt base heat resistant alloy or a cermet base alloy is engaged at least at a portion where the inner surface of the nozzle body composed of iron base alloy and a plunger member come in contact. The above engagement is fixed by either a thermal-fit means or a cooling-fit means. A come-out preventive member is arranged in the end part at the opening hole side of the above sleeve. The hardness of this sleeve at 600°C is ≥ 350 Hv. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention is a nozzle used in an injection molding machine that heats, stirs and melts a material, injects it into a molten or semi-molten state and injects it into a mold to mold a product in order to injection-mold a light alloy such as magnesium and aluminum. It relates to members.
[0002]
[Prior art]
In an injection molding machine for injection molding a light alloy such as magnesium or aluminum, as shown in FIG. 3, the injection molding machine includes a cylindrical cylinder 1 and a nozzle member 6, both of which are formed by a plurality of fasteners such as bolts 5. They are connected together. A heater 4 is provided on the outer peripheral surface of the cylinder 1. At the time of injection molding, the granular light alloy chip 3 put into the cylinder 1 is brought into a molten state by the heater 4. The light alloy such as magnesium in a molten state is extruded by the plunger member 2 moving forward and backward in the hollow portion of the cylinder 1, is injected into the mold 8 through the nozzle hole 7 of the nozzle member 6, and is formed into a predetermined product shape. Molded.
[0003]
Light alloys such as magnesium have a very low viscosity in a molten state and therefore have high fluidity. For this reason, the nozzle member is brought into contact with the nozzle position being shifted between the nozzle receiving portion having a spherical surface formed on the mold or a sprue bush incorporated in the mold and the nozzle member provided at the tip of the cylinder. When injected, the melted light alloy leaks from the gap between the misalignments, making molding impossible.
[0004]
Thus, the nozzle member is an important member for the light alloy injection molding machine, and various proposals have been made.
[0005]
For example, in Patent Document 1, as a nozzle tip portion of a nozzle body joined to a nozzle touch portion of a mold, a thermal conductivity of 20 kcal / m.m. hr. It is described that a material such as SUS having a temperature of not more than ° C is used. This is because when the nozzle body and the mold made of an iron-based material are joined, by preventing the heat from flowing out of the nozzle body to the mold, and by preventing the temperature drop in the temperature uncontrolled region at the nozzle tip, This prevents solidification of a molding material made of a molten metal in a non-temperature-controlled region at the nozzle tip, thereby reliably performing metal injection molding.
[0006]
Patent Document 2 discloses an injection-molding member for injection-molding a low-melting-point metal, in which a base material of an outer member is made of a nickel-base heat-resistant alloy, and a contact between the base material and the molten metal for injection. The surface of the part is coated with a cobalt-based heat-resistant alloy, which satisfies the conditions of erosion resistance, abrasion resistance, and high-temperature strength required for injection molding machine members of molten metal such as Mg. What can prevent damages such as shortening of service life, breakage and breakage is disclosed.
[0007]
[Patent Document 1]
JP-A-9-10907 [Patent Document 2]
Japanese Patent No. 2862799 [0008]
[Problems to be solved by the invention]
Since the nozzle member used for the injection molding machine for light alloys such as aluminum and magnesium reaches a high temperature range of about 600 ° C. during use, selection of the material is very important. In other words, the material forming the nozzle member is required to have a high strength that does not soften even in a high temperature range of about 600 ° C. and that it does not melt even when it comes into contact with the molten light alloy.
[0009]
As a material that almost satisfies these requirements, an iron-based tool steel having excellent heat resistance such as JIS standard SKD61, which is a hot die steel, has been used as a nozzle member. However, although these tool steels are excellent in erosion resistance and wear resistance, when the plunger slides through the nozzle member, there is a problem that the nozzle member is susceptible to galling and molding becomes impossible. Was.
[0010]
In addition, if the base material of the nozzle member is made of a nickel-based heat-resistant alloy and the entire surface in contact with the molten metal on the inner peripheral surface is lined with a cobalt-based alloy that is excellent in heat resistance and erosion resistance, erosion resistance, abrasion resistance, and high temperature strength However, the cost is very high, which is economically disadvantageous.
[0011]
Accordingly, the present invention has been made in view of the above problems, and provides a nozzle member for a light alloy injection molding machine that is low in cost, has excellent erosion resistance, can prevent damage due to galling, and is advantageous in regenerating the nozzle member. Aim.
[0012]
[Means for Solving the Problems]
The nozzle member for a light alloy injection molding machine of the present invention is characterized in that a sleeve made of a cobalt-based alloy or a cermet-based alloy is fitted to at least a part of the inner surface of a nozzle body made of an iron-based alloy and a plunger member in contact therewith. I do.
[0013]
In the present invention, a sleeve made of a cobalt-based alloy or a cermet-based alloy is fixed to at least a part of an inner surface of a nozzle body made of an iron-based alloy, which is in contact with a plunger member, by any one of shrink fitting and cold fitting. It is characterized by. Further, a stopper member for preventing the sleeve from coming off is provided at the opening-side end of the sleeve.
[0014]
Furthermore, the hardness at 600 ° C. of the sleeve fitted to at least a part of the inner surface of the nozzle body that comes into contact with the plunger member is Hv350 or more.
[0015]
[Action]
According to the configuration of the present invention, a nozzle body is made of an iron-based alloy without using a nickel-based heat-resistant alloy as in the prior art, and a sleeve made of a cobalt-based alloy or a cermet-based alloy is provided on the inner surface of the nozzle body. Since the fitting is performed, galling with the plunger member is prevented, and an inexpensive nozzle member for a light alloy injection molding machine can be obtained.
[0016]
By providing a stopper member at the end on the opening side of the sleeve, even if the stress generated by shrink fitting or cold fitting at the injection molding temperature is reduced, the sleeve can be reliably prevented from falling out of the nozzle body.
[0017]
In order to prevent galling with the injection plunger member during injection molding, it is desirable that the sleeve has a hardness at 600 ° C. of Hv 350 or more.
[0018]
Further, when the nozzle is replaced, only the sleeve need be replaced instead of the entire nozzle member, which is excellent in economy.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic sectional view of a nozzle member according to a first embodiment of the present invention. In FIG. 1, the main body 10 of the nozzle 9 was manufactured by processing into a predetermined shape using an iron-based alloy.
[0020]
Next, by weight, a cobalt-based alloy powder composed of Cr: 10.9%, B: 1.6%, Si: 0.5%, Mn: 0.5%, and substantially Co and inevitable impurities is used. The sleeve 11 having an outer diameter of 55 mm, an inner diameter of 45 mm, and a length of 150 mm was manufactured by pressure sintering by the HIP method.
[0021]
Further, the sleeve 11 was shrink-fitted to a portion of the inner surface of the nozzle body 10 which was in contact with a plunger member (not shown) to obtain a nozzle member for a light alloy injection molding machine of the present invention. The nozzle member for a light alloy injection molding machine of the present invention may be obtained by cold fitting the sleeve 11 to the inner surface of the nozzle body 10.
[0022]
When the nozzle member of this example was incorporated into a light alloy injection molding machine and injection molding was performed for a long period of time, no galling with the plunger member was observed on the inner surface of the nozzle, and stable molding was possible.
[0023]
FIG. 2 is a schematic sectional view of a nozzle member according to another embodiment of the present invention. In FIG. 2, the main body 10 of the nozzle member is made of an iron-based alloy, and a sleeve 11 made of a cobalt-based alloy is fitted on the inner surface thereof. Further, a retaining member 12 made of an iron-based alloy was screwed to the opening end of the sleeve 11 with a screw 13 to obtain a nozzle member for a light alloy injection molding machine of the present invention.
[0024]
FIG. 3 is a schematic sectional view of a nozzle member according to another embodiment of the present invention. The retaining member 12 was configured to be fastened to the nozzle body 10 with a bolt 14.
[0025]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to the nozzle member for light alloy injection molding machines of this invention, the galling between the nozzle inner surface and the plunger member at the time of injection is not recognized, and injection molding can be performed stably.
[Brief description of the drawings]
FIG. 1 is a schematic sectional view of a nozzle member according to a first embodiment of the present invention.
FIG. 2 is a schematic sectional view of a nozzle member according to another embodiment of the present invention.
FIG. 3 is a schematic sectional view of a nozzle member according to another embodiment of the present invention.
FIG. 4 is a schematic sectional view of a light alloy injection molding machine.
[Explanation of symbols]
1 cylinder, 2 plunger member, 3 light alloy tip, 4 heater,
5 bolt, 6 nozzle member, 7 nozzle hole, 8 mold,
9 nozzle member, 10 nozzle body, 11 sleeve,
12 retaining member, 13 screwed part, 14 bolt

Claims (4)

A nozzle member used in an injection molding machine for injection-molding a molten light alloy, wherein at least a part of an inner surface of a nozzle body made of an iron-based alloy and a plunger member contact each other, a sleeve made of a cobalt-based heat-resistant alloy or a cermet-based alloy. A nozzle member for a light alloy injection molding machine, wherein the nozzle member is fitted. The nozzle member for a light alloy injection molding machine according to claim 1, wherein the fitting is fixed by any one of shrink fitting and cold fitting. 3. The nozzle member for a light alloy injection molding machine according to claim 1, wherein a stopper member is provided at an end of the sleeve on the opening side. The nozzle member for a light alloy injection molding machine according to any one of claims 1 to 3, wherein the sleeve has a hardness at 600 ° C of Hv350 or more.

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