WO2004087351A1 - Heat insulation plunger sleeve for die casting machine - Google Patents

Abstract

A heat insulation plunger sleeve for a die casting machine exhibiting excellent heat insulation/thermal insulation performance and excellent stability as a structural member and capable of sustaining stabilized pressure casting operation by suppressing temperature drop of non-ferrous metal molten metal as much as possible. The heat insulation plunger sleeve for a die casting machine comprises a first metal layer of highly heat resistant metal on the inner circumferential side, a second metal layer on the outer circumferential side, and a ceramics layer formed between the first and second metal layers, wherein the ceramics layer is formed of ceramics powder compacted to have a relative density of 50%-90% and/or ceramics fibers.

Description

 Description Thermal insulation plunger sleeve for die casting machine

 TECHNICAL FIELD The present invention relates to a heat insulating plunger sleeve used for producing a non-ferrous metal product by a die casting machine. Background art

 Production of non-ferrous metal products using a die casting machine is performed by injecting molten non-ferrous metal such as aluminum alloy or magnesium alloy into a mold cavity through a plunger sleeve.

 As shown in Fig. 1, a plunger sleeve for a die-casting machine (also called a "short sleeve") (10) is used by attaching it to a die-casting die (80). The mold (80) is composed of a fixed mold (82) to which the plunger sleeve (10) is attached, and a movable mold (not shown) detachable from the fixed mold (82).

 The plunger sleep (10) has a hollow cylindrical shape, and the hollow portion (12) has a fixed base attached to the mold (80) and a tap hole that communicates with the inside of the mold (80).

(13), the opening on the tip side where the plunger tip (70) enters

(14).

 A hot water supply port (15) for injecting the non-ferrous metal melt into the plunger sleeve (10) is provided on the peripheral surface on the tip side of the plunger sleeve (10).

A connecting means (16) such as a flange for attaching the plunger sleeve (10) to the fixed die (82) is formed on the base end side of the plunger sleeve (10). With the plunger sleep (10) connected to the mold (80), with the plunger tip (70) slightly entering through the opening (14), the molten non-ferrous metal is poured from the hot water supply port (15), By pressing the plunger tip (70) toward the mold side, the non-ferrous metal melt is press-fitted into the mold (80), and injection molding is performed.

 The plunger sleep (10) has a resistance to corrosion, a thermal shock resistance, a sliding property against the plunger tip (70), Friction resistance is required. For the plunger sleeve (10), an alloy tool steel (JIS-G440) represented by SKD61 is used as a material having these properties.

 However, when the non-ferrous metal melt is supplied to the plunger sleeve (10) in the above-described assembling operation, if the temperature drop of the non-ferrous metal melt is large, defects such as a hot boundary and a poor running of the melt occur in the manufactured product. It is difficult to ensure stable quality. In addition, due to the temperature drop of the non-ferrous metal melt, the non-ferrous metal melt solidifies on the inner surface of the plunger sleeve (10), and the plunger tip (70) wears out, adversely affecting the service life of the plunger sleeve (10). There is a problem that the quality is deteriorated due to the contamination.

 One of the causes of the temperature drop of the non-ferrous metal melt is that the thermal conductivity of the plunger sleeve (10) is high (the thermal conductivity of the SKD61 alloy tool steel: about 34 W / m · K). Is mentioned.

In order to suppress the temperature drop of the non-ferrous metal melt due to the plunger sleeve (10), as shown in Fig. 7, the ceramic layer (90) (92) of the plunger sleeve (10) has a ceramic sintered layer ( 94) has been devised. Providing the ceramic sintered layer (94) improves the heat insulation of the plunger sleeve (10). The plunger-sleeve (10) in Fig. 7 has a ceramic sintered body cylinder that forms a ceramic sintered layer (94) on the outer periphery of a cylindrical inner metal layer (90) divided into half cylinders. It is formed by fitting it in a state to form an annular shape, and further fitting an outer metal body divided into half cylinders around its outer periphery.

 However, since the plunger sleeve (10) has a different coefficient of thermal expansion between the metal layers (90) and (92) and the ceramic sintered layer (94), the molten non-ferrous metal alloy is placed inside the plunger sleeve (10). When injected, cracks, cracks, peeling, etc. may occur between the metal layer (90) and the ceramic sintered layer (94). Disclosure of the invention

 SUMMARY OF THE INVENTION An object of the present invention is to provide a heat insulating material for a die casting machine which has excellent heat insulating properties and stability as a structural member, suppresses a temperature drop of a non-ferrous metal melt as much as possible, and can maintain a stable pressurizing operation. It is to provide a plunger sleeve.

 In order to achieve the above object, a heat insulating plunger sleeve for a die casting machine of the present invention comprises a first metal layer made of a metal having excellent heat resistance on an inner peripheral side. The first metal layer comprises a second metal layer on an outer peripheral side. A ceramics layer is formed between the layer and the second metal layer, and the ceramics layer is formed from ceramic powder and / or ceramic fibers compacted to a relative density of 50% to 90%.

By interposing a ceramics layer compacted with ceramic powder and / or ceramic fibers between the first metal layer and the second metal, it exhibits excellent heat insulation. The heat insulating effect of the conventional sintered ceramic layer utilizing the low thermal conductivity of ceramics depends on the thickness of the ceramic layer, and it was necessary to thicken the ceramic layer to obtain the desired heat insulating effect. However However, as in the present invention, by forming the ceramic layer by consolidating the ceramic layer without sintering it with ceramic powder and / or ceramic fiber, it exhibits a thermal insulation performance that greatly exceeds the effect expected from the thickness of the ceramic layer. . This heat insulation performance is due to the fact that a heat insulating region is formed to consolidate the ceramic powder or ceramic fiber without sintering, and the interfacial thermal resistance between the ceramic layer and the first and second metal layers is remarkable. Probably because of the high price. Since the interfacial thermal resistance at the layer boundary is extremely high, it is considered that the ceramic layer exhibits excellent heat insulation even with a very thin layer thickness of 2 mm or less, or even 1 mm or less. BRIEF DESCRIPTION OF THE FIGURES

 FIG. 1 is an explanatory diagram showing a use state of a plunger sleeve for a die casting machine.

 FIG. 2 is a cross-sectional view along the axial direction of the heat-insulating plunger sleeve for a die-casting machine according to the present invention.

 FIG. 3 is a cross-sectional view taken along the line II-II of FIG.

 FIG. 4 is an explanatory view showing one example of a method for manufacturing the heat insulating plunger sleeve for a die casting machine of the present invention.

 FIG. 5 is a sectional view showing a different embodiment of the present invention.

 FIG. 6 is a cross-sectional view of the measurement sample.

 FIG. 7 is a cross-sectional view of a conventional plunger sleeve for a die casting machine. BEST MODE FOR CARRYING OUT THE INVENTION

The heat insulating plunger sleeve (10) for a die casting machine of the present invention is a ceramic powder compacted to a relative density of 50% or more and 90% or less during a sleeve. And / or a ceramic layer (30) made of ceramic fiber is provided. The relative density is defined as the ratio between the density of the ceramic layer and the true density of the ceramics constituting the ceramic layer.

 As shown in FIGS. 2 and 3, the plunger sleeve (10) has a first metal layer (20) made of a metal having excellent heat resistance on the inner peripheral side, and an outer periphery of the first metal layer (20). A ceramic layer (30) made of ceramic powder and / or ceramic fiber compacted to a relative density of 50% or more and 90% or less, and the same or different metal as the first metal layer (20) on the outer periphery of the ceramic layer (30) And is formed by concentrically laminating a second metal layer (40) made of.

 In the following, an embodiment in which the ceramic layer (30) has a single-layer structure will be described. However, as shown in FIG. 5, the ceramic layer (30) may have a plurality of structures.

The first metal layer (20) is preferably made of a metal material having corrosion resistance to the non-ferrous metal melt and having excellent heat resistance and abrasion resistance, and the inner surface in contact with the metal melt may be subjected to nitriding treatment. desirable. For example, in terms of% by weight, C: 0.32 to 0.42%, Si: 0.8 to 1.2%, Mn: 0.5% or less, Cr: 4.5 to 5. 5%, Mo: 1.0 to 1.6%, V: 0.5 to 1.2%, the balance being substantially Fe, C: 0.4 to 0.5%, Si : 0.15 to 0.5%, Cr: 1.3 to 1.7%, Mo: 0.15 to 0.3%, A1: 0.7 to 1.2%, remaining real Fe nitride, C: 0.73 to 0.83%, Si: 0.15 to 0.35%, Cr: 3.8 to 4.5%, W: 17.0 to 19.0%, V: 0.8 to 1.5%, balance: High-speed steel of Fe, etc., C: 0.4 to 0.7%, S i: 0.5 to 2.0%, Mn: 0.5% or less, Cr: 4.0 to 6.0%, W: 10.0 to; L5.0%, V: 0.5 Up to 1.0%, with the balance being substantially Fe. Wear. Further, for the first metal layer (20), a sintered metal having a composite structure in which titanium carbide is mixed as a dispersed phase in a matrix of titanium or a titanium alloy may be used. As this sintered metal, titanium (T i) is used as a matrix, and titanium carbide (T i C) occupying 20 to 30% by area is mixed therein. i-Mo alloy (Mo content: 20 to 35% by weight) as matrix, with titanium carbide (TiC) occupying 20 to 30 area% mixed with Ti alloy-Ti C-based composite sintered metal. 'It is advantageous to design the thickness of the first metal layer (20) to be thin within a range where a predetermined mechanical strength is maintained, as described later. According to the total thickness of the plunger sleeve (10) and the hole diameter of the hollow portion (12), it is desirable to determine the range of about 3 to 15 mm, preferably about 3 to 10 mm.

The ceramic layer (30) is formed by compacting ceramic powder or ceramic fibers. As ceramic materials, oxides, nitrides, borides, carbides, can illustrate Kei compound ceramics, for example, A l ₂ 〇 _{3, A 1 2 03 - S} i O 2, Z R_〇 _2, S i 〇 ₂ , Si ₃ N ₄ , BN, Ti B ₂ , Si C, and Mo Si ₂ at least one material can be used. When a plurality of types are used, they may be a simple mixture or a composite. The average particle size of the ceramic powder is preferably 0.5 / zm to 100 m, and the ceramic fiber is preferably 1 βm to 20 m in diameter and 10 ^ πι to 30 mm in length. The ceramic fiber may be a non-woven fabric.

The thickness of the ceramic layer (30) is preferably at least 0.1 mm in order to obtain a predetermined heat insulating effect. However, if the thickness is too large, the stability of the laminated structure may be impaired. Therefore, the thickness is preferably 2 mm or less, and more preferably 1 mm or less. Further, it is more preferable that the thickness be 0.5 mm or less. In this way, the layer thickness is reduced and the powdery or fibrous The ceramic layer (30) follows the thermal expansion and contraction of the metal layer (20) (40) generated during the manufacture and use of the plunger sleeve (10) by consolidating the lamic material without sintering. The ceramic layer (30) acts as a thermal stress absorption relaxation layer. In order to obtain a predetermined heat insulating effect while securing the robustness of the laminated structure, it is appropriate that the relative density of the ceramic layer (30) is 50% or more and 90% or less, and 70% or more and 90% or less. It is desirable to do the following.

 As the second metal layer (40), the same type as that of the first metal layer (20) can be used. However, since the second metal layer (40) is not directly in contact with the non-ferrous metal melt, corrosion resistance to the non-ferrous metal melt is not required. Further, since the second metal layer (40) is insulated by the ceramic layer (30), high heat resistance is not required unlike the first metal layer (20). Since the plunger tip (70) does not slide as in (20), wear resistance is not required. Therefore, carbon steel for machine structural use such as S45C (JIS-G4051) or steel material for general structure such as SS400 (JIS-G3101) may be used as appropriate. .

 The thickness of the second metal layer (40) may be appropriately adjusted within a range where a predetermined mechanical strength is maintained, and depends on the total thickness of the plunger sleep (10) and the hole diameter of the hollow portion (12). Therefore, it is preferable to determine the range of about 10 to 50 mm, preferably about 15 to 40 mm.

The method of manufacturing the plunger sleeve (10) will be described by way of an example. The plunger sleeve (10) is, as shown in FIG. 4, a first cylindrical body (22) constituting a first metal layer (20). A second cylindrical body (42) constituting a second metal layer (40) having an inner diameter larger than the outer diameter of the first cylindrical body (22) is concentrically provided on the outer periphery of the first cylindrical body (22). ) And the second cylindrical body (42) are filled with ceramic powder and / or ceramic fiber, and the first cylindrical body (22) is extended from the inside and the second cylindrical body (42). Hydrostatic pressure including working load in the direction of pressing from outside Performs pressure forming such as pressing (HIP), hot extrusion, and cold isostatic pressing. As a result, the ceramic powder and / or fibers between the cylinders (22) and (42) are pressed by the cylinders (22) and (42) to form a consolidated ceramic layer (30). Unlike the sintered ceramic, the ceramic layer (30) follows the expansion and contraction of the cylindrical body (22) (42) in the press forming process, so that the ceramic layer (20) has a corrugated shape. Become. When the pressure molding is performed by HIP, an unbonded layer (34) having low adhesion is formed at the layer boundary between the ceramic layer (30) and the first metal layer (20). Since (34) has a remarkably high interfacial thermal resistance, it has been confirmed that the heat insulation is significantly improved. After performing the pressure forming process, it may be cut into a predetermined length, and both end surfaces may be closed with end plates (17, 18) as shown in FIG. One end plate (Π) can be formed in a flange shape as connection means (16) to the mold (80). End plate (17)

After installing (18), the plunger sleeve (10) can be obtained by performing appropriate machining such as opening a hot water supply port (15).

 The plunger sleeve (10) having a three-layer structure of the first metal layer (20), the ceramic layer (30) and the second metal layer (40) has been described above.

As shown in FIG. 5, the second metal layer (40) is made into a plurality of layers (41) (41), and each metal layer (41)

A structure in which a ceramic layer (30) made of ceramic powder and / or ceramic fiber having a relative density of 50% or more and 90% or less can be provided between (41). The number of ceramic layers (30) may be appropriately determined according to the required conditions such as heat insulation.

 The spacing between the ceramic layers (30) may be determined as appropriate, but it is preferable that the spacing does not exceed the thickness of the first metal layer (20).

<Example 1>

In order to examine the thermal insulation of the plunger sleeve (10) of the present invention, Five types of plate-shaped measurement samples (S) with different thicknesses of the metal layer were prepared, and a thermal conductivity measurement test was performed. In addition, a comparative sample (S ') containing a ceramic sintered plate instead of ceramic powder was prepared, and a thermal conductivity measurement test was similarly performed.

 As shown in FIG. 6, the measurement samples (S1 to S5) were formed with a concave portion (54) in a base layer (52) made of the same material as the second metal layer (40), and a ceramic fiber (56) was formed. It was filled, covered with a surface layer (58) made of the same material as the first metal layer (20), and subjected to HIP processing. The comparative sample S ′ was produced by applying a cold pressure from the surface layer (58) side with the ceramics sintered plate interposed between the base layer (52) and the surface layer (58).

 The sample and each condition of the test are shown below.

 • Measurement sample

 Sample size: diameter 50 mm, thickness 19 mm, surface layer thickness 3 mm

 Ceramic layer thickness: S 1 = 0.2 mm, S 2 = 0.3 mm, S 3 = 0.5 mm, S 4 = 0.9 mm, S 5 = 1.5 mm, Comparative sample SI is thick 6 mm ceramic sintered plate

 Surface material: 0.3% by weight C: 0.3%, Si: 1.0%, Mn: 0.4%, Cr: 5.0%, Mo: 1.25%, V: 1.0%, balance substantially F e (thermal conductivity 34 W / mK)

Base material: tensile strength 4 2 k 111111 ² 3 S 400 (thermal conductivity 59 / mK)

Ceramic material… A 1 2O 3-S i ₂ fiber

 • Thermal conductivity measurement test conditions

 Measurement method: temperature gradient method

 Measurement direction: sample thickness direction (surface layer is set to high temperature side)

 Measuring temperature ... 3 4 to 4 5

Temperature difference at the measuring end: 7. 9 to 8. 25 (Heat flow per unit area: about 14 kW / m

 Sample pressure: Approx. 72 kPa (High thermal conductive grease is used at the interface between the device and the sample)

 •Measurement result

 The apparent heat of the inner layer calculated from the measured value of the entire sample (total thickness) and thermal conductivity (α), and the measured value (α) and the thermal conductivity of the sample constituent materials according to Fourier's law. Table 1 shows the conductivity (αι).

 table 1

 Unit: W / m · K As shown in Table 1, the total thermal conductivity of the measurement sample (S) and the surface layer are the thermal conductivity of the first metal layer (20) forming the sample (34 W / m · K). It can also be seen that the thermal conductivity was almost the same as that of the comparative sample S 'using a 6-mm-thick ceramic sintered plate.

The ceramic layer (30) was omitted, and the entire contact interface between the surface layer (58) and the base layer (52) was completely diffusion-bonded (3 mm surface layer, 16 mm base layer, 19 mm total wall thickness). In the case of), the thermal conductivity of the whole sample is about 52.9 W / m · K when calculated according to Fourier's law. Comparing this with the measured value of the thermal conductivity () in Table 1 above, the thermal insulation effect of the ceramic layer (30) is extremely large. I understand that

 The test samples S 1 to S 5 were formed by heat insulation of the layer (34) formed between the ceramic layer (30) and the first metal layer (20) and the entire interface sandwiching the ceramic layer (30). It was also confirmed that the homogeneity of the properties was high, and that there was little heat deviation in the circumferential and axial directions, and little distortion due to the heat deviation.

<Example 2>

 By changing the thickness of the ceramic layer (30), a plunger sleeve (10) having the shape shown in Figs. 2 and 3 is manufactured by HIP, and the first metal layer (10) is formed by the difference in the thickness of the ceramic layer (30). The inner surface condition of 20) was observed and evaluated. The metal and ceramic materials used were the same as in Example 1.

 The dimensions and HIP conditions of the plunger sleeve (10) are shown below.

 First metal layer (20): inner diameter 150 mm, thickness 7 mm

 Ceramic layer (30): 1 mm, 2 mm and 3 mm thick

 Second metal layer (40): outer diameter 260 mm

 Overall length of plunger sleeve (10): 100 mm

 HIP conditions: 1100 bar, 950 ° C

 Observation of the inner surface of the first metal layer (30) of the manufactured plunger sleeve (10) revealed the following results.

 Table 2

表 2を参照すると、 セラミックス層（30)の厚さが薄い場合には（2 m m 以下）、 セラミックス層（30)が全体的に均一に圧縮を受け、 第 1金属層 (20)の内面が真円又はほぼ真円を維持するのに対し、 セラミックス層（3 0)の厚さが 3 m mの場合には、 局部的に応力が集中し、 第 1金属層（20) に凹みが生じてしまうことがわかる。 なお、 第 1金属層（20)に凹みが生 じた場合には、 真円にするために別途機械加工を施せばよい。

Referring to Table 2, when the thickness of the ceramic layer (30) is small (2 mm Below), the ceramic layer (30) is uniformly compressed as a whole, and the inner surface of the first metal layer (20) maintains a perfect or almost perfect circle, whereas the thickness of the ceramic layer (30) is When the thickness is 3 mm, it can be seen that the stress is locally concentrated and the first metal layer (20) is dented. If a dent is formed in the first metal layer (20), it may be separately machined to make it a perfect circle.

 From the above, it can be seen that the thickness of the ceramic layer (30) is desirably 2 mm or less, and more desirably 1 mm or less, from the viewpoint of manufacturing. Example 3>

 Comparison with the plunger sleeve (10) of the present invention having a ceramic layer (30) having a thickness of 2 mm and a ceramic sintered body (94) having a relative density of 98% and a thickness of 6 mm (see FIG. 7) Plunger sleeves were prepared, and the actual production was performed by injecting ADC12 (A1 alloy) melt at 680 into both plunger sleeves.

 As a result, the plunger sleeve (10) of the present invention has a perfect circular shape on the inner surface of the first metal layer (20) of the plunger sleeve (10) even if the structure is manufactured for three thousand times (shot). The degree was kept. This is because the ceramic layer (30) is consolidated rather than sintered, so even if the first metal layer (20) thermally expands due to the injection of the molten metal, the stress is relaxed by the ceramic layer (30). That's because. On the other hand, in the comparative shot sleeve, cracks occurred in the ceramic sintered body (94) at 200 shots, the roundness of the first metal layer (90) was reduced, and it was impossible to manufacture. Specifically, the plunger tip (70) stopped working. This is due to the difference in thermal expansion between the ceramic sintered body (94) and the first metal layer (90) that occurs when the molten metal is supplied.

As described above, the plunger sleep (10) having the ceramic layer (30) of the present invention is less than the plunger sleeve using the ceramic sintered body (94). In addition, it is understood that it has excellent durability. Industrial applicability

 INDUSTRIAL APPLICABILITY As described above, the present invention provides a die cast which is excellent in heat insulation and heat retention and stability as a structural member, can suppress the temperature drop of the non-ferrous metal melt as much as possible, and can maintain a stable pressurized structure operation. Useful as an insulated plunger sleeve for machines.

Claims

The scope of the claims 1. At the base end of the hollow cylinder, there is a tap hole (13) that can communicate with the mold (80) and connection means (16) that can communicate with the mold (80), and a plunger tip (70) at the tip. A plunger sleeve for a die-casting machine having an opening (14) to be inserted and a hot water supply port (15) for injecting molten metal into the peripheral surface, wherein the plunger sleeve has heat resistance on the inner peripheral side. It has a first metal layer (20) made of excellent metal, a second metal layer (40) on the outer peripheral side, and a ceramic layer (20) between the first metal layer (20) and the second metal layer (40). 30), and the ceramic layer (30) is made of ceramic powder and / or ceramic fiber compacted to a relative density of 50% or more and 90% or less, and is a heat-insulating plunger sleeve for a die-cast machine. .  2. The second metal layer (40) is formed from a plurality of metal layers (41) (41), and the relative density between each metal layer (41) (41) is 50% or more and 90% or less. The heat-insulating plunger sleeve for a die-casting machine according to claim 1, wherein a ceramic layer (30) made of compacted ceramic powder and / or ceramic fiber is interposed.  3. The heat-insulating plunger sleeve for a die-cast machine according to claim 1, wherein the thickness of the ceramic layer (30) is 2 mm or less. 4. The heat insulating plunger sleeve for a die casting machine according to claim 1, wherein the thickness of the first metal layer (20) is 3 to 15 mm.  5. The first metal layer (20) is, by weight%, C: 0.32 to 0.42%, Si : 0.8 to 1.2%, Mn: 0.5% or less, Cr: 4.5 to 5.5%, Mo: 1.0 to: 1.6%, V: 0.5 to 1 3. The heat-insulating plunger sleeve for a die-casting machine according to claim 1 or 2, wherein the balance is substantially Fe. 6. ceramic layer (30), A l ₂ 〇 _{3, A 1 2 O 3 -} S i O 2, Z r O 2 S i 〇 _{2, S i 3 N 4,} BN, T i B 2, S i C, and, M o S i ₂ or Ranaru least one powder or fiber in which claim 1 or claim 2 insulation plunger scan Li part for die casting machines according to selected from the group.