JPS61103658A - Injection cylinder for die casting machine - Google Patents

Abstract

PURPOSE:To prevent the thermal deformation, crack and abrupt wear of an inside cylinder and to extend considerably the life of an injection cylinder by compressing and fitting the inside cylinder having ultra high resistance to heat and wear to the part near the molten metal pouring hole of the inside circumferential surface of said cylinder and providing a heat medium introducing hole to an outside cylinder. CONSTITUTION:The inside cylinder 2 consisting of the material such as ceramics or cermet having the ultra high resistance to heat and wear is preliminarily compressed and fitted to the inside circumferential surface of the outside cylinder of the aluminum injection cylinder at least near the molten metal pouring part 6 thereof. The plural holes 4 for introducing the heat medium are provided to the cylinder 1 and the cylinder 2 is heated to prevent the thermal deformation, crack and abrupt wear during the molten metal pouring of the cylinder 2, by which the cylinder life is considerably extended.

Description

[Detailed description of the invention] [Industrial application field] The present invention provides aluminum (AI), magnesium (Mg
), zinc (Zn), iron (Fe), tin (S n), copper (C
u), molybdenum (Mo), etc., and its alloys at high temperature (400-1600°C) molten metal (hereinafter referred to as molten metal)
This invention relates to an improvement of an injection sill installed in a casting device for mold casting.

[Conventional technology]

A metal mold a remains consists of a movable mold and a fixed mold, and the void (hereinafter referred to as the mold void) of a mold (usually a metal mold, hereinafter simply referred to as the mold) has a void in a shape corresponding to the required product shape. This is a precision casting method in which molten metal is injected under pressure and solidified to produce cast products. For this mold casting, the above-mentioned A1. Mtl, Zn, Fe, Sn, Cu, M.

etc. and their alloys have been applied.

The temperature of the molten metal varies depending on the metal or alloy, but is approximately 40℃.
Since the temperature is in the range of 0 to 1600℃, the area between the pouring hole of the injection molding device installed in the casting equipment and the mold cavity is exposed to the high temperature of the molten metal, which may cause thermal deformation, oxides, or welding of the molten metal. happens.

Therefore, especially in mold casting of metals with high melting points such as iron, copper, and their alloys, heat-resistant materials that can withstand high-temperature molten metal of 900 to 1600° C. are used as the material for the injection molding. However, since iron-based heat-resistant alloys such as hot work tool steel generally have a short life, alloys based on W or Mo are used.

[Problem that the invention seeks to solve]

In mold casting, which involves high-temperature casting such as iron and copper,
Even when super heat-resistant alloys are used, cracks and rapid wear occur in the injection molding ring, and the molten metal bites into, adheres to, or melts into the cylinder wall where the molten metal comes into contact with the flow during injection, resulting in continuous failure. This poses a problem in that not only does it become impossible to form a mold aiL, but also the life of the injection mold is significantly shortened.

Furthermore, since the heat-resistant alloys based on W and Mo have low thermal conductivity, they rapidly absorb the heat retained in the molten metal and lower its temperature. For this reason, the fB hot water injected into the injection molding becomes highly viscous before it is press-fitted into the mold cavity, and there is a problem in that it becomes difficult to inject and press-fit it with a piston.

The present invention eliminates these problems, α, and prevents thermal deformation, cracks, or 4 Q
An object of the present invention is to provide an injection cylinder for forming mold castings, which can extend its life without causing wear and tear, and can continuously obtain sound mold casting products without lowering the temperature of the casting hot water. This is the purpose.

[Means for solving problems]

As shown in Fig. 1.2, the injection molding ring for mold casting of the present invention has ceramics, thermium γY, etc. The inner cylinder 2 made of a non-ferrous metal material having super heat resistance and super wear resistance is fitted with an appropriate tightening margin, and
This is characterized in that the outer cylinder 1 is provided with one or more holes 4 through which a heat medium for heating and cooling can be introduced.

The inner fill 2 may be fitted over the entire length of the outer cylinder 1 in the vicinity of the injection port 6, or may be divided into a plurality of pieces, or may be fitted only to the necessary portions. You may wear it.

[For production]

Since the material of the inner vi2 is a non-metallic H1 heat-resistant and super wear-resistant material such as ceramics or therme fushi, it has extremely excellent heat resistance, corrosion resistance, wear resistance, etc., and is not wettable by molten metal.

In addition, since the thermal conductivity is low, the retained heat of the injected molten metal is not rapidly taken away, so it does not make injection press-fitting by the piston 7 difficult. , thermal shock resistance, and mechanical properties may be inferior to metal materials, but by selecting the material and fitting with an appropriate tightening margin, this α can be sufficiently compensated for.

Inner vI2 fits into outer cylinder 1 with appropriate tightening margin (static fit)
Therefore, compressive stress (hereinafter referred to as preliminary compressive stress) is generated in the inner cylinder. This pre-compression stress works extremely effectively for this type of tool.

That is, since the injection cylinder first injects the molten metal from the injection port 6, a large thermal shock occurs on the surface of the inner cylinder 2 near the lower part 12a of the injection port 6.

Further, after the interior 1i@2 is filled with molten metal until it is injected by the piston 7, a temperature gradient occurs between the inner and outer surfaces (the inner surface is at a high temperature) due to rapid heating of the inner surface.

Both of the two spatulas generate a large tensile stress due to the thermal gradient l2, but the pre-compressive stress of the inner 1i112, which was generated in advance by fitting the outer 1i11 with a tightening margin, is balanced with this tensile stress. It is possible to reduce the tensile stress to zero or to limit the generation of tensile stress to a small amount.

Further, tensile stress is further added due to the liquid pressure of the molten metal pushed out by the piston 7, but the structure that generates this preliminary compressive stress is effective in canceling out the stress.

The degree of fitting with interference (fitting rate) varies depending on the shape, material, casting conditions, etc. of the inner and outer cylinders, but o, oos ~
It is preferable to select an opening of 0.02, and it is also preferable to vary this fitting ratio in the axial direction.

The outer fillill hole 4 has heat for heating or cooling:
The introduction of the medium plays a major role in alleviating the temperature gradient.

Heating or cooling is selected depending on casting conditions, product shape, material, degree of fitting, etc. As the heat medium, an appropriate fluid such as water, air, gas, or steam is selected.

〔Example〕

FIG. 1 is a longitudinal cross-sectional view showing an embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along the line AA in FIG.

The outer cylinder 1 if 11 is attached to the fixed mold 5 so as to communicate with the mold fill (not shown), and the inner cylinder 2 is fitted into the inner circumference near the molten metal injection port 6 with an appropriate tightness, and the outer cylinder 1 The outer end is pressed by iE3 which is fixed to the end of.

The outer fill is provided with six holes 4 for introducing the heat medium, and a device (not shown) for introducing the heat medium is provided.
is connected to.

A piston 7 is fitted into the inner periphery of the inner cylinder 2 and the outer cylinder 11, and injects and presses the molten metal injected from the injection port 6 into the mold cavity 1.

The inner cylinder 2 is made of a super heat-resistant material such as ceramics or cermet, which has excellent heat resistance, corrosion resistance, and abrasion resistance, is difficult to wet with molten metal, and has low (or high) thermal conductivity.

As for ceramics, SiC, 5IALON (Ceraty X consisting of Si, At!, O, N)
Altos, 3AffitOs, 2SiOt, Z
ro 2 , S isN 4, etc. are used.

The tIS1 table shows the various properties of SiC, which is an example of this and is made of a pressureless sintered A-type phase and has a density of 95% or more.The characteristics are listed as follows. It is.

1) It has superior thermal shock resistance compared to alumina, is less susceptible to damage due to thermal shock from molten metal, etc., and can extend its life several times longer.

2) Thermal conductivity is comparable to tungsten carbide and several times higher than alumina, so it can prevent overheating of the outer cylinder.

3) It is stable in air up to 1,000 degrees Celsius, which prevents thermal deformation during high-temperature use and maintains the same thermal strength.

4) Excellent chemical resistance allows it to withstand wetting even in molten metal.
It is also extremely resistant to ``claws'', which are the biggest weakness of injection cylinders.

5) To withstand telegrams, it can be used in combination with an outer cylinder and lid made of charcoal material.

6) Excellent 11M wear resistance, which improves service life and eliminates or saves lubricants.

In addition, wear and tear on the piston, which is the mating tool, can be reduced.

〔Effect of the invention〕

As detailed above, the injection ring for mold casting of the present invention can be used not only for mold casting using molten aluminum, but also for mold casting of high melting point metals such as iron-based alloys. Preliminary compressive stress is applied to the inner cylinder, and the temperature can be controlled from the outer cylinder.
It does not suffer from thermal deformation, cracks, or rapid wear and tear, and its useful life can be greatly extended. Furthermore, the outer cylinder is made of lqa material for hot molding, and can be reused for a long period of time by simply replacing the inner cylinder, making it extremely economical and providing numerous industrial advantages.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view showing an embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along the line AA in FIG. 1: Outer cylinder, 2: Inner cylinder, 4: Hole, 6: Inlet agent Patent attorney Takashi Honma (procedural amendment written document) March 8, 1939

Claims (1)

[Claims] At least near the molten metal injection hole on the inner peripheral surface of the outer cylinder into which the piston is inserted, an inner cylinder made of a non-ferrous metal material having super heat resistance and super wear resistance, such as ceramics or cermet, is fitted with an appropriate tightness. An injection cylinder for a mold casting machine, characterized in that the outer cylinder is provided with one or more holes through which a heat medium can be introduced.