JP2008201080A - Cylinder for molding machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve problems that since a cylinder for an injection molding machine molding a resin and the like to which glass fibers or the like are added in a large quantity requires high wear resistance, the cylinder in which hard particles such as tungsten carbide are dispersed in a lining layer of the cylinder for the molding machine is used, but if the lining layer contains hard particles in a large quantity, machinability becomes extremely inferior. <P>SOLUTION: The cylinder for the molding machine comprises a base in which the lining layer contains nickel, and hard particles in each of which tungsten carbide is dispersed in metal tungsten. Further, the cylinder is characterized in that the content of the tungsten carbide in the hard particles is 20-80% at an area ratio, the content of the hard particles occupying the lining layer is 20-80% at the area ratio, the maximum length of the hard particle is 250 μm or shorter, and the lining layer contains tungsten boride at an area ratio of 5-20%. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a cylinder having a composite structure that is mainly used in a plastic molding machine and has a lining layer formed on the inner surface of a hollow cylindrical cylinder base material.

  Cylinders for molding machines used for molding plastic products etc. are made of hollow cylindrical cylinder base material mainly made of steel in order to suppress corrosion and wear due to resin or additives added to resin during thermoforming. A lining layer made of an alloy having wear resistance and corrosion resistance (hereinafter referred to as a wear and corrosion resistance alloy) is formed on the inner surface. As a method for forming a lining layer made of a wear-resistant and corrosion-resistant alloy on the inner surface of the cylinder base material, a centrifugal casting method, a hot isostatic pressing method, a shrink fitting method, or the like is employed.

  Nickel-based alloys, cobalt-based alloys, and the like are used as wear-resistant and corrosion-resistant alloys that form the lining layer. Further, the wear resistance is further improved by dispersing hard particles such as tungsten carbide (WC), niobium carbide (NbC), titanium carbide (TiC), etc., in these wear and corrosion resistant alloys by centrifugal casting. Lining layers have also been proposed.

  Patent Document 1 includes, by weight, tungsten carbide: 30 to 45%, nickel + cobalt (total amount): 35 to 50%, molybdenum: 1% or less, chromium: 10% or less, boron: 1 to 3%, A tungsten carbide composite lining material for centrifugal casting containing silicon: 1 to 3%, manganese: 2% or less, iron: 8 to 25%, carbon: 1% or less is disclosed. Moreover, tungsten carbide consists of spherical powder with an average particle diameter of 6-12 micrometers, the volume ratio of tungsten carbide in a lining layer is 25-45%, and the particle | grain space | interval of tungsten carbide is 8-20 micrometers as an average free process. Are listed. Furthermore, it is described that the shape of tungsten carbide is made spherical to prevent the counterpart material from being damaged by metal friction. In addition, it is described that tungsten carbide particles are made fine and the interval between the particles is adjusted to make the processing time equivalent to that of a conventional Ni-based alloy lining material.

Patent Document 2 discloses an injection molding made of a steel selected from the group consisting of ASTM 193B-16 carbon steel and deplexed non-rust steel and having a corrosion and wear resistant nickel alloy liner made of carbide and boride containing alloy. A high temperature, corrosion resistant bimetal cylinder for machine use is disclosed. The cylinder alloy liner has the following composition:
Ingredient Weight%
Carbon 1.5 to 4.5
Silicon 1.5 to 3.5
Boron 1.0 to 3.0
Cobalt 1.0 to 6.0
Tungsten 30.0 to 60.0
Nickel Residue Also described is a high temperature corrosion resistant bimetallic cylinder containing not more than 7.0 wt% chromium and further not more than 15.0 wt% iron in the alloy liner.

In Patent Document 3,
Ingredient Weight percent Tungsten carbide 30-45
Nickel 22-61
Cobalt 37 or less Chrome 12 or less Boron 1.3 to 3.0
Silicon 0.7-3.3
Manganese 1.0 or less Iron 3.3 or less Carbon A cylinder having a lining layer obtained by integrally melting an alloy composed of 0.6 or less by centrifugal casting is disclosed. Also, the tungsten carbide has a different concentration in the thickness direction of the lining layer in the range of 40 to 80% by volume, and the tungsten carbide concentration in the layer near the substrate of the lining layer is set higher than the concentration in the near layer. A lining layer having a tungsten carbide concentration difference between the layers is described. Furthermore, it is stated that the tungsten carbide particles used are preferably relatively small particles of 100 mesh or less.

JP 7-290186 A Japanese Patent Laid-Open No. 6-15708 Japanese Patent Publication No.54-32413

  High wear resistance is required for a cylinder mounted on an injection molding machine for molding a resin containing a large amount of glass fiber or the like. Therefore, a cylinder in which hard particles such as tungsten carbide are dispersed is used as a lining layer of a cylinder for a molding machine. However, if a large amount of hard particles are contained in the lining layer in order to improve the wear resistance, the machinability is extremely inferior. Therefore, the machining time of the lining layer is increased, and problems such as a decrease in productivity and an increase in manufacturing cost occur.

  Patent Document 1 describes that tungsten carbide particles have an average particle diameter of 6 to 12 μm, and the machinability is improved by setting the particle interval to 8 to 20 μm. However, such a relatively small particle size tungsten carbide is easily melted and decomposed during heating and melting in actual production, and is difficult to be included in the lining layer of the cylinder.

  Patent Document 2 discloses an alloy liner containing 30 to 60% by weight of tungsten in a high temperature corrosion resistant bimetal cylinder for an injection molding machine, but machinability is not considered. Patent Document 3 discloses a non-ferrous alloy lining layer containing 30 to 45% by weight of tungsten carbide in a cylinder such as an extruder, but machinability is not considered.

  The present invention has been made against the background described above, and an object of the cylinder for a molding machine of the present invention is to provide a cylinder having excellent wear resistance and excellent machinability at low cost.

  In view of the above object, as a result of earnest research on the abrasion resistance and machinability evaluation of the lining layer containing various hard particles in the base containing nickel and the manufacturing conditions by the centrifugal casting method, the present inventors The present inventors have arrived at the present invention with the following knowledge.

  1. By adding hard particles in which tungsten carbide is dispersed in metallic tungsten into a nickel base having excellent corrosion resistance as a lining layer, the wear resistance can be improved without significantly impairing the machinability of the lining layer.

  2. By further crystallizing or precipitating tungsten boride on the hard particles of the present invention, the spacing between the hard particles can be appropriately dispersed, and the machinability can be further improved while maintaining the wear resistance. .

  In a cylinder for a molding machine in which a lining layer containing a wear-resistant and corrosion-resistant alloy is formed on the inner surface of a hollow cylindrical steel outer cylinder, the lining layer includes a base containing nickel, and tungsten carbide is dispersed in metallic tungsten. It is characterized by comprising hard particles.

  The content of tungsten carbide in the hard particles is 20 to 80% in terms of area ratio.

  The content of the hard particles in the lining layer is 20 to 80% by area ratio.

  The maximum length of the hard particles is 250 μm or less.

  The lining layer further includes 5 to 20% tungsten boride in area ratio.

  The component of the said lining layer is the mass%, C: 1.5-3.5%, Si: 0.1-3.0%, B: 0.5-3.0%, W: 40.0-60 It has a composition consisting of 0.0% and the balance substantially Ni.

  The lining layer is further characterized by containing at least one element selected from Cr: 1.0-10.0% or Fe: 1.0-15.0% by mass.

  The lining layer further includes at least one element selected from the group consisting of Mn: 2.0% or less and Cu: 5.0% or less in terms of mass%.

  The lining layer is further characterized by containing Co: 1.0 to 10.0% by mass.

  The lining layer is formed by a centrifugal casting method.

  The molding machine cylinder of the present invention will be described in detail below.

[1] Lining layer structure (1) The cylinder of the present invention has a lining layer in which hard particles in which tungsten carbide is dispersed in metallic tungsten are dispersed in a wear and corrosion resistant alloy mainly composed of nickel. The biggest feature. Tungsten carbide has a high hardness of Hv 2000 to 3000, and contributes to improved wear resistance. On the other hand, the hardness of metallic tungsten is about Hv360. By including tungsten carbide in metallic tungsten, it is possible to adjust the hardness of the hard particles as a whole and to adjust the wear resistance and machinability. Tungsten carbide is preferably dispersed substantially uniformly in a metallic tungsten in a lamellar or spherical shape.

(2) Content of tungsten carbide in hard particles is 20 to 80% in area ratio
The amount of tungsten carbide contained in the hard particles is 20 to 80% by area ratio, and more preferably 30 to 70%. If the tungsten carbide contained in the hard particles is less than 20% in terms of area ratio, the effect of improving wear resistance is insufficient. On the other hand, if the area ratio exceeds 80%, it becomes excessively hard and the machinability is remarkably lowered, which is not preferable.

(4) The content of hard particles contained in the lining layer is 20 to 80% in area ratio
The amount of hard particles contained in the lining layer is 20 to 80%, more preferably 30 to 70% in terms of area ratio. When the hard particles contained in the lining layer are less than 20% by area ratio, the effect of improving the wear resistance is insufficient. On the other hand, when the area ratio exceeds 80%, it becomes excessively hard and the machinability is remarkably lowered, which is not preferable.

(3) The maximum length of hard particles is 250 μm or less If the maximum length of hard particles contained in the lining layer is longer than 250 μm, the uniformity of the microscopic structure is impaired and the microscopically uneven wear on the inner surface of the cylinder. In addition to wear due to corrosion or the like, it is not preferable because hard particles are likely to fall off or fall off during use.

(5) Tungsten boride contained in the lining layer is 5 to 20% by area ratio
In the lining layer of the present invention, tungsten boride may be dispersed in an area ratio of 5 to 20%. This is preferable because it increases the hardness of the base and contributes to improvement of wear resistance. Further, when manufactured by centrifugal casting, tungsten boride is centrifuged together with the hard particles, and the intervals between the hard particles contained in the lining layer are appropriately dispersed, thereby contributing to improvement of machinability. If the area ratio of tungsten boride is less than 5%, the above effect cannot be obtained sufficiently. On the other hand, if the tungsten boride exceeds 20% in terms of area ratio, the amount of tungsten boride is excessive, and mechanical properties such as bending strength are lowered, which is not preferable.

[1] Composition of lining layer (% by mass)
(1) Essential component (a) C: 1.5 to 3.5%
C mainly combines with W to improve wear resistance by forming tungsten carbide. Moreover, some C couple | bonds with the alloy element in a base | substrate, and forms a carbide | carbonized_material. If C is less than 1.5%, the amount of tungsten carbide is insufficient, and sufficient wear resistance cannot be obtained. On the other hand, when C exceeds 3.5%, the amount of tungsten carbide becomes excessive, so that machinability is lowered and mechanical properties such as bending strength are lowered. The C content is preferably 2.0 to 3.0%.

(B) Si: 0.1 to 3.0%
Si has the effect of lowering the melting point of the alloy, and when manufactured by centrifugal casting, it contributes to improving the homogeneous distribution of the alloy in the circumferential and axial directions of the cylinder by increasing the fluidity of the molten alloy. In addition to being dissolved in the matrix, Si is partly combined with alloy elements such as Ni to crystallize or precipitate silicide, thereby contributing to improved wear resistance. If Si is less than 0.1%, this effect cannot be sufficiently obtained. On the other hand, when Si exceeds 3.0%, the amount of silicide becomes excessive, and mechanical properties such as bending strength are deteriorated, which is not preferable. The Si content is preferably 1.0 to 2.5%.

(C) B: 0.5 to 3.0%
B has the effect of lowering the melting point of the alloy in the same manner as Si described above, and when manufactured by centrifugal casting, by increasing the fluidity of the molten alloy, the homogeneous distribution of the alloy in the circumferential direction and the axial direction of the cylinder. Contributes to improved performance. B combines with alloy elements such as Ni and W to crystallize or precipitate borides, and contributes to improvement in wear resistance. When manufactured by the centrifugal casting method, the tungsten boride is centrifuged together with the W particles to disperse the particle intervals of the hard particles, thereby contributing to improvement of machinability. If B is less than 0.5%, this effect cannot be sufficiently obtained. On the other hand, if B exceeds 3.0%, the amount of boride becomes excessive, the fluidity of the molten alloy decreases, and the above effect cannot be obtained, and the mechanical properties such as the bending strength decrease, which is not preferable. The content of B is preferably 1.0 to 2.0%.

(D) W: 40.0 to 60.0%
W is a main element that mainly forms the hard particles of the present invention, and improves the wear resistance by the hard particles made of metallic tungsten and tungsten carbide. Further, a part of W combines with B in the matrix to crystallize or precipitate tungsten boride, contributing to improvement of wear resistance and homogeneous dispersion of hard particles. In other words, the presence of tungsten boride between the hard particles provides excellent machinability while having excellent wear resistance. When W is less than 40.0%, the amount of hard particles and tungsten boride is insufficient, and sufficient wear resistance cannot be obtained. On the other hand, if W exceeds 60.0%, the amount of hard particles and tungsten boride becomes excessive, and the machinability is lowered and mechanical properties such as bending strength are lowered.

(E) Remaining Ni
Ni is a main element that forms a base for holding hard particles. Ni exists mainly in a metallic state, and a part thereof combines with B to form a boride, strengthening the base. Ni is excellent in corrosion resistance and has a feature that its alloy has a lower melting point than other metal elements, such as Fe, by appropriately controlling B. Further, the balance of the lining layer of the present invention may be substantially Ni, and may contain, for example, gas components such as nitrogen, oxygen and hydrogen, and impurities inevitably mixed in production.

[2] Optional components The lining layer may appropriately contain the following elements depending on the purpose and usage of the cylinder.

(A) Cr: 1.0 to 10.0%
Cr mainly combines with B to form a boride, and partly combines with C to form a carbide to improve wear resistance. Further, the remainder is preferably added in order to dissolve in the base and improve the corrosion resistance. If Cr is less than 1.0%, the above effect is insufficient. On the other hand, when Cr exceeds 10.0%, the amount of boride becomes excessive, and the machinability is lowered and mechanical properties such as bending strength are lowered. In addition, as the melting point increases, the fluidity of the molten metal decreases, which is not preferable.

(B) Fe: 1.0 to 15.0%
Fe is inevitably mixed in from Fe contained in the base material by eroding the base material when the lining material is melted, which mainly forms the lining layer, during casting by the centrifugal casting method. Moreover, Fe has the effect | action which reduces the fluidity | liquidity of the molten metal opposite to Si and B, and may be added for fluidity | liquidity adjustment of a molten metal. If Fe is less than 1%, the above action is insufficient. On the other hand, if Fe exceeds 15%, corrosion resistance is lowered and mechanical properties such as bending strength are lowered, which is not preferable.

(C) Mn: 2.0% or less Mn has a deoxidizing action of the molten metal. Further, Mn is mixed from Mn contained in the base material by eroding the base material when the lining material is melted during centrifugal casting. The effect is sufficient if Mn is 2.0%. The Mn content is preferably 0.1 to 0.6%.

(D) Cu: 5.0% or less Cu is an element useful for improving the corrosion resistance of the alloy by dissolving in a matrix. Even if Cu exceeds 5.0%, this effect is saturated. Further, since Cu is an extremely expensive element, it has an effect of increasing the melting point of the molten metal, and it is desirable to determine its content in consideration of economy and use conditions.

(E) Co: 10.0% or less Co has the same effect as Ni, and is an element particularly useful for improving the toughness of the alloy and the corrosion resistance against sulfuric acid gas. Further, Co is an extremely expensive element, and the corrosion resistance is significantly lowered in an environment where hydrofluoric acid is generated in cylinder applications. Therefore, it is desirable to determine the content in consideration of economy and use conditions.

  The cylinder for a molding machine of the present invention contains tungsten carbide in the lining layer, and is excellent in wear resistance. Moreover, the cylinder for molding machines of this invention can improve machinability by including metallic tungsten. Further, the machinability can be further improved by controlling the dispersion of the hard particles by tungsten boride.

  The invention is illustrated in detail by the following examples. The present invention is not limited to these.

  As the outer cylinder, a machine structural steel having an outer diameter of φ100 mm and a length of 800 mm provided with a through hole having an inner diameter of φ34 mm in the axial direction was prepared. Further, as a powder for forming the lining layer, a mixed powder prepared by mixing a predetermined amount of the hard particles of the present invention prepared in advance with the base alloy powder was prepared. Here, several kinds of hard particles having different tungsten carbide contents were used. Further, several kinds of hard particles having different particle diameters were used.

  First, the mixed powder was charged into the through hole of the outer cylinder, and both ends of the through hole were sealed with a metal lid. This was heated to a predetermined temperature in a heating furnace to melt the mixed powder, and then set on a centrifugal casting machine. This was rotated at a predetermined rotational speed by a centrifugal casting machine, and a cylinder material was produced by forming a lining layer having a thickness of about 5 mm on the inner surface of the through hole of the cylinder outer cylinder. After cooling this, the lids at both ends were processed and removed to obtain a cylinder material having an outer diameter of φ100 mm and a length of 760 mm.

  50 mm was cut from one end face of the cylinder material, and a test material having an outer diameter of 100 mm and a length of 50 mm was collected. A test piece for measuring chemical components was collected from the vicinity of the inner diameter φ30 mm position (position corresponding to the inner diameter of the product) of the lining layer, and the chemical components of each test material were measured. Table 1 shows the results.

  Sample No. in Table 1 1 to 6 are embodiments of the present invention, in which the lining layer is composed of a base containing nickel and hard particles in which tungsten carbide is dispersed in metallic tungsten.

  Specimen No. Reference numeral 7 is a comparative example in which the lining layer is composed of a base containing nickel and metal tungsten particles.

  Specimen No. 8 is a conventional example, in which the lining layer is made of a nickel alloy having corrosion resistance.

  Specimen No. 9 is a conventional example, in which the lining layer is composed of a base containing nickel and tungsten carbide particles.

  In addition, specimen No. 1 to 6, the area ratio and the maximum length of the hard particles at the position corresponding to the product inner diameter were measured using an optical microscope and an image analyzer. Furthermore, using a scanning electron microscope (SEM) and an image analysis device, the area ratio of tungsten carbide and the area ratio of tungsten boride in the hard particles were determined.

  Similarly, the test material No. 7, the area ratio of metal tungsten particles, the maximum length, and the area ratio of tungsten boride were measured. In addition, specimen No. The area ratio of tungsten carbide particles, the maximum length, and the area ratio of tungsten boride in 9 were measured.

  Furthermore, an abrasion test piece having an outer diameter of φ10 mm × length of 15 mm including the lining layer of each test material was collected, and an abrasive wear test of the lining layer was performed to evaluate the wear resistance. The abrasive wear test was performed by pressing the lining layer forming surface of each test piece against a SiC abrasive sandpaper (# 400) rotating at 150 rpm at a pressure of 90 N for a certain time. At that time, the weight before and after the test was measured, and the difference between the two was used as the weight loss, and the wear resistance was evaluated. The evaluation is based on the conventional test material No. The wear loss of 8 was set to 100, and the relative weight loss of other test materials was compared.

  FIG. 1 shows a schematic diagram of the abrasive wear test. In FIG. 1, B is the lining layer portion of the test piece, and A is the outer cylinder portion of the test piece. a is the SiC abrasive sandpaper (# 400), and P is the pressure.

  Further, from the lining layer of each test material, a bending test piece of 5 mm × 1.5 mm × 40 mm was taken from the position corresponding to the inner diameter of the product, and the bending strength was measured by performing a four-point bending test.

  The lining layer was processed to have an inner diameter of 30 mm by using a BTA processing machine with an inner diameter of the cylinder material (outer diameter: φ100 mm × length: 710 mm) after each specimen was collected. At that time, the time required for processing was measured. The evaluation of machinability is based on the conventional test material No. The processing time of 8 was set to 1.0, and the relative processing time of other specimens was compared.

  Table 2 shows the above test results and evaluation results. That is, hard particle area%, (tungsten carbide / hard particle) area ratio, hard particle maximum length (μm), tungsten boride area%, wear loss, machinability, and bending strength (MPa).

  FIG. 2 shows a schematic cross-sectional view of the cylinder material of the present invention. In FIG. 2, the part A is an outer cylinder, the part B is a layer in which hard particles are dispersed, the part C is a layer in which hard particles are poor, and the part D is a hollow part. The mixed powder melted in the heating furnace is welded to the outer cylinder (b) by centrifugal casting. In addition, since the hard particles in the molten mixed powder have a large specific gravity, they are aggregated on the outer cylinder side during centrifugal casting to form a layer (b) where the hard particles are dispersed. The remaining portion having a small specific gravity forms a layer (c) having poor hard particles on the hollow portion (d) side. The cylinder for a molding machine according to the present invention is used as a lining layer by processing and removing part of the part C and the part B and exposing the part B.

  FIG. 3 is a metallographic photograph of the part A shown in FIG. 3 shows the sample No. of the invention example. The metal structure photograph of 1 is shown. The white particles (for example, 2) in the part B in FIG. 3 are the hard particles of the present invention. Reference numeral 11 denotes a boundary between a layer in which hard particles are dispersed (b) and a layer in which hard particles are poor (c). Reference numeral 12 denotes a product inner diameter equivalent position. The cylinder material is processed to an inner diameter up to the product inner diameter equivalent position (12) shown in FIG. 3 to obtain a cylinder for a molding machine of the present invention.

  FIG. 4 shows a schematic diagram of the lining layer of the present invention. In FIG. 4, 1 is the base, 2 is the hard particle of the present invention, 3 is tungsten boride, and d is the maximum length of the hard particle 2.

  FIG. 1 is a scanning electron micrograph of one lining layer. In FIG. 5, the gray portions are 20 to 100 μm and the relatively large massive grayish white portions are hard particles 2 of the present invention, and the relatively small white granular portions of 1 to 5 μm are tungsten boride 3. In the lining layer of the present invention, it can be seen that tungsten boride 3 is dispersed between the hard particles 2.

  FIG. 6 shows a schematic diagram of the hard particles of the present invention. In FIG. 6, 4 indicates tungsten carbide and 5 indicates metallic tungsten.

  Sample No. of the present invention. The wear loss of 1-6 is 9-17. Compared to 8, the wear resistance is very good. On the other hand, the test material No. The machinability of Nos. 1 to 6 is 1.2 to 3.2. There is no fading compared to 8. That is, the test material No. 1-6 have excellent wear resistance and good machinability. Moreover, the test material No. of this invention. The bending strength of 1 to 6 is 502 to 669 MPa and has sufficient strength.

  The test material No. In No. 6, the content of tungsten boride is as low as 2%, so that the interval between the hard particles is narrowed and the hard particles are concentrated. Therefore, the wear resistance is improved, but the machinability is slightly inferior.

  Sample No. of Comparative Example Reference numeral 7 denotes a lining layer made of a base containing nickel and metal tungsten particles. That is, the test material No. No. 7 does not contain tungsten carbide in the lining layer and is composed only of metallic tungsten. Since it does not contain hard tungsten carbide, machinability is as good as 1.7, but wear loss is 92, which is extremely inferior in wear resistance.

  Sample No. of conventional example 8 is a known nickel-based cylinder. Since it does not contain hard particles, the machinability is good but the wear resistance is remarkably inferior.

  Sample No. of conventional example 9 is a structure in which the lining layer is composed of a base containing nickel and tungsten carbide particles. That is, metallic tungsten is not contained in the lining layer, which is outside the scope of the present invention. Specimen No. Since No. 9 does not contain metallic tungsten, wear resistance is improved, but machinability is remarkably inferior.

  Sample No. of the present invention. 1 was used to manufacture a molding machine cylinder having an outer diameter of 90 mm, an inner diameter of 30 mm, and a total length of 500 mm. At that time, the processing time of the inner lining layer was the same as that of the conventional nickel-based cylinder, and the processing cost was also the same. Moreover, when this cylinder for molding machines was subjected to actual injection molding, it showed wear resistance 10 times or more that of a conventional nickel base cylinder.

  The cylinder for a molding machine of the present invention exhibits excellent wear resistance in general plastic molding. In particular, a resin containing a large amount of glass fiber or the like exhibits extremely excellent wear resistance and contributes to productivity improvement of plastic molding improvement. Moreover, since the cylinder for molding machines of this invention is excellent in machinability, the processing cost of the lining layer at the time of cylinder manufacture can be reduced, and the cylinder which is excellent in abrasion resistance can be provided at low cost.

It is the schematic of an abrasive wear test. It is a cross-sectional schematic diagram of the cylinder for molding machines of this invention. Sample No. of the present invention. 1 is a metallographic photograph taken by an optical microscope. It is a schematic diagram of the lining layer of this invention. Sample No. of the present invention. 1 is a scanning electron micrograph of one lining layer. It is a schematic diagram of the hard particle | grains of this invention.

Explanation of symbols

a SiC abrasive sandpaper, P pressure,
1 lining layer base, 2 hard particles of the present invention, 3 tungsten boride,
4 Tungsten carbide, 5 Metal tungsten,
(B) Base material, (b) Layer in which hard particles are dispersed, (c) Layer in which hard particles are poor, (d) Hollow part,
d maximum length of hard particles,
11 The boundary between the layer in which hard particles are dispersed and the layer in which hard particles are poor,
12 Product internal diameter equivalent position

Claims (10)

In a cylinder for a molding machine in which a lining layer containing a wear-resistant and corrosion-resistant alloy is formed on the inner surface of a hollow cylindrical steel outer cylinder, the lining layer includes a base containing nickel, and tungsten carbide is dispersed in metallic tungsten. A cylinder for a molding machine, characterized by comprising hard particles. The cylinder for molding machines according to claim 1, wherein the content of tungsten carbide in the hard particles is 20 to 80% in terms of area ratio. The cylinder for a molding machine according to claim 1 or 2, wherein the content of the hard particles in the lining layer is 20 to 80% in terms of area ratio. The cylinder for a molding machine according to any one of claims 1 to 3, wherein the maximum length of the hard particles is 250 µm or less. The cylinder for a molding machine according to any one of claims 1 to 4, wherein the lining layer further contains 5 to 20% of tungsten boride in an area ratio. The component of the said lining layer is the mass%, C: 1.5-3.5%, Si: 0.1-3.0%, B: 0.5-3.0%, W: 40.0-60 The cylinder for a molding machine according to any one of claims 1 to 5, having a composition consisting of 0.0% and the balance substantially Ni. The lining layer further contains at least one element selected from Cr: 1.0 to 10.0% or Fe: 1.0 to 15.0% by mass%. Cylinder for molding machine. 8. The molding machine according to claim 6, wherein the lining layer further contains at least one element selected from the group consisting of Mn: 2.0% or less and Cu: 5.0% or less by mass%. Cylinder. The cylinder for a molding machine according to any one of claims 6 to 8, wherein the lining layer further contains Co: 1.0 to 10.0% by mass. The molding machine cylinder according to claim 1, wherein the lining layer is formed by a centrifugal casting method.