JPH02263903A - Manufacture of combined cylinder - Google Patents

Abstract

PURPOSE:To manufacture a combined cylinder having high and uniform joining stress and high reliability even if small in diameter by joining a metal-made outer cylinder and a ceramic-made inner cylinder through an intermediate layer formed with HIP treatment. CONSTITUTION:A ring-like lower part liner 10a and lower cover 12 are fitted into lower end side in the axial direction of the metal outer cylinder member 7 of Cr-Mo steel, etc., and fixed with welding, etc., and the ceramic-made columnar member 8 having excellent wear resistance is concentrically supported to the above member 7 with the upper and lower linears 10a, 10b. Successively, the metal powder of copper alloy, etc., having coefficient of linear expansion larger than that of the member 7 is charged into gap between the above members 7, 8 from a powder charging hole 16 at the upper liner 10b, and after packing the powder into the gap, an upper cover 11 is fixed with welding, etc., to the upper end side of the member 7 to form combined raw material 15. The HIP treatment is executed to this raw material 15 to form the intermediate layer 3, and also the intermediate layer 3 and the outer cylinder member 7 are diffusion-joined and after cooling slowly, the cylinder hole 6 is bored in the above member 8 to manufacture the combined cylinder 1.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a method for manufacturing a composite cylinder equipped in an injection molding machine or an extrusion machine used for injection or extrusion molding of plastics, ceramics, ferrite, rare earth magnetic powder, etc. Regarding.

(Prior art) Conventionally, the inner circumferential surface of the outer cylinder of the cylinder body installed in injection molding machines or extrusion machines for plastics, etc. has been made of Ni-based alloy Co-based base metal with excellent wear resistance and corrosion resistance. The inner layer was formed by centrifugal casting, hot isostatic pressing (hereinafter referred to as HIP), or the like.

However, in recent years, with the shift to composite materials from plastic materials,
While increasing the proportion of mixtures such as glass fiber in plastics, injection or extrusion molding of ceramics, ferrite, rare earth magnetic powder, etc. has also come to be carried out. For this reason, the inner layer made of the above-mentioned non-ferrous alloy lacks wear resistance, and early deterioration of the inner layer causes a reduction in the service life of the cylinder.

Therefore, in order to solve the above problem, a composite cylinder is provided in which the inner layer of the cylinder is made of ceramic having excellent wear resistance and corrosion resistance. The composite cylinder is usually made by shrink-fitting a metal pipe onto the outer periphery of a ceramic pipe, and is made up of an inner cylinder made of ceramic and an outer cylinder made of metal. Further, in order to prevent the shrink fit stress from decreasing due to the difference in linear expansion coefficient between the outer cylinder and the inner cylinder when the cylinder is used at high temperatures, for example, Japanese Patent Laid-Open No. 60-221223 discloses It has also been proposed that an intermediate layer made of a metal having a coefficient of linear expansion larger than that of the outer cylinder is formed between the outer cylinder and the inner cylinder, as disclosed in .

(Problems to be Solved by the Invention) As mentioned above, composite cylinders are joined by shrink fitting, but the ceramics forming the inner cylinder are generally
Since the toughness is low and the bending strength is also low, only a low shrink fit ratio can be selected during the shrink fit. moreover,
In terms of processing accuracy, it is important to uniformly fit the joining surfaces in the above-mentioned shrink fit, that is, the inner circumferential surface of the metal outer cylinder and the outer circumferential surface of the ceramic inner cylinder or intermediate layer, over the entire surface by machining. It is extremely difficult. Therefore, uniform bonding is not obtained on the bonding surfaces, and the shrink fit stress acting on the bonding surfaces, that is, the bonding stress between the outer cylinder and the inner cylinder or the intermediate layer when the cylinder is used, is not uniform. The distribution was uniform, and there was a drawback that sufficient bonding strength could not be obtained.

For this reason, when the cylinder is used at particularly high temperatures, the bonding stress gradually decreases due to thermal expansion of the outer tube as the cylinder heats up, causing the inner tube to come off or the bonding stress to be unevenly distributed. As a result, a gap is partially formed in the joint surface, and the inner cylinder cannot be backed up uniformly, so that in severe cases, an accident may occur in which the inner cylinder is destroyed.

In particular, in so-called small-diameter cylinders, where the inner diameter of the cylinder is smaller than 40 mmφ, the inner and outer diameters of the outer cylinder are small, so the shrink fit rate can only be lower than the low shrink fit rate mentioned above. . For this reason, it is not possible to obtain enough shrink fit stress to sufficiently tighten and hold the inner cylinder, and the reality is that small-diameter composite cylinders with inner cylinders made of ceramics have not been put into practical use. .

The present invention has been made in view of the above-mentioned problems, and aims to provide a method for manufacturing a composite cylinder that has strong and uniform bonding stress regardless of the shrink fit rate or the processing accuracy of the bonded surfaces. There is.

(Means for Solving the Problems) The present invention, which has been made to achieve the above-mentioned object, has an intermediate structure between an outer cylinder 2 made of metal forming a cylinder body and an inner cylinder 4 made of a wear-resistant material. A method for manufacturing a composite cylinder 1 on which a layer 3 is formed, comprising: inserting a cylindrical member 8 made of ceramic with excellent wear resistance concentrically into an outer cylinder member 7 made of a high-strength metal material;
The gap between the two members 7 and 8 is filled with metal powder 9 having a coefficient of linear expansion larger than that of the outer cylinder member 7 to form a composite material 15.
After forming and subjecting the composite material 15 to hot isostatic pressing,
The structure of the invention is that the cylinder hole 6 is bored in the axial center of the cylindrical member 8 along the axial direction.

(Function) In the present invention, by filling the gap between the outer cylindrical member and the cylindrical member with a metal powder having a linear expansion coefficient larger than that of the outer cylindrical member and performing HIPIP treatment, a high-density sintered material made of the metal powder is formed. The body layer was formed as an intermediate layer. In this case, the intermediate layer, regardless of the processing accuracy of the outer circumferential surface of the cylindrical member,
The entire outer peripheral surface is uniformly bonded. On the other hand, the cylindrical member is not easily deformed or damaged during the HIP process, and 1 (the high tightening caused in the intermediate layer by the IP process is held by force. Since the bonding surface with the surface is diffusion bonded by HIPIP processing and metallurgically integrated, the outer cylinder and the intermediate layer are bonded uniformly and firmly.

A cylinder hole is opened in the cylindrical member made of the composite material thus manufactured, and the cylindrical member is processed into an inner cylinder. still,
Since there is a large difference in melting point between the cylindrical member and the intermediate layer, HIPIP
Not treated or diffusion bonded.

As described above, in the composite cylinder manufactured by the present invention, the cylindrical member and the outer cylinder member are uniformly and firmly joined via the intermediate layer, so that the inner cylinder, intermediate layer, and outer cylinder are bonded to each other. Uniform and strong bonding is achieved over the entire surface to be bonded. In addition, since the intermediate layer has a larger coefficient of linear expansion than the outer cylinder, even when the cylinder is used at high temperatures, the bonding stress does not decrease (and no gaps are formed between the joint surfaces of each member, so that the outer cylinder and the intermediate layer , it is possible to grip the inner cylinder evenly and strongly and back it up.

(Example) Examples of the present invention will be described below with reference to the drawings.

FIG. 1 shows a cross section of a main part of a composite cylinder 1 manufactured by the manufacturing method according to this embodiment. The cylinder 1 has a wear-resistant layer 3 on the inner peripheral surface of a metallic outer cylinder 2 forming a cylinder body, with an intermediate layer 3 made of a sintered body of metal powder having a coefficient of linear expansion larger than that of the outer cylinder 2. An inner cylinder 4 made of ceramic with excellent properties is fixed concentrically.

In the figure, reference numeral 5 denotes a hopper hole communicating with a hopper for charging the molding material into the cylinder.

A cylinder hole 6 is provided in the axial center of the inner cylinder 4 along the axial direction.
A screw, piston, plunger, etc. is usually inserted into the cylinder hole, and the molding material introduced from the hopper hole 5 is extruded or injected into a mold or die under high pressure to form the mold. form the body.

The method for manufacturing the composite cylinder will be described below.

FIG. 2 shows H in the manufacturing process of the composite cylinder.
The configuration of the composite material 15 before IP processing is shown.

First, the composite material 15 will be explained according to the manufacturing process.

A ring-shaped lower liner 10a and a lower lid 12 are provided at the lower end side in the axial direction of the outer cylinder member 7, which is made of a high-strength material such as Cr-Mo steel or high-Mn steel, and is used to form the outer cylinder 2.
Fit together and secure using an appropriate method such as welding. A ceramic cylindrical member 8 for forming the inner cylinder 4 is inserted into the outer cylinder member 7 and fitted into the ring hole of the lower liner 10a. Then, while inserting the upper liner 10b having the powder injection hole 16 into the upper part of the cylindrical member 8, the outer cylindrical member 7
It fits on the upper end side. The upper and lower liners 10a, 1
The cylindrical member 8 is supported in a circular manner at the axial center of the outer cylinder member 7 by the cylindrical member 0b.

The cylindrical member 8 is preferably selected from materials that not only have excellent wear resistance but also have good machinability so that the cylinder hole 6 described above can be easily formed. for example,
"Machinable Ceramic" (trade name, manufactured by Ishiya Yakuhin ■) has excellent wear resistance and machinability, and is suitable for the cylindrical member.

Next, a metal powder 9 having a coefficient of linear expansion larger than that of the outer cylinder member 7 is introduced into the gap between the cylindrical member 8 and the outer cylinder member 7 through the powder injection hole 16 formed in the upper liner. to be filled. The metal powder 9 is subjected to HIP, which will be described later.
Since it is processed into a high-density sintered body layer and forms an intermediate layer, it needs to have a coefficient of linear expansion larger than that of the outer cylinder member 7 and a melting point higher than the HIP processing temperature.

Examples of such metals include, for example, JP-A-62-1743
The copper alloy described in Publication No. 1 can be used.

Furthermore, when filling the metal powder 9, the powder 9 is introduced while vibrating the outer cylindrical member 7 into which the cylindrical member 8 is inserted using an appropriate vibrator or the like so as to obtain a high packing density. is desirable.

After filling the metal powder 9, the upper lid 11 is equipped with a degassing pipe 14.
is fitted onto the upper end side of the outer cylindrical member 7, and the two are fixed together by an appropriate method such as welding to form the composite material 15.

Next, the composite material 15 is heated to 600'C while being evacuated from the degassing pipe 8. This not only exhausts air and moisture in the filled layer of the alloy powder 9 (e.g., H2O, CO, etc.)

The main purpose of this operation is to discharge CO□, N2). If composite material 15 were simply degassed at room temperature, it would be HI.
In the case of P treatment, the aforementioned gas components are released from the columnar member 8 during the HIP treatment, and defects caused by the gas components are likely to be formed in the intermediate layer or at the joints of each member.

After the degassing treatment, the metal powder 9 is
is formed as an intermediate layer which is a high-density sintered body. As described above, the intermediate layer is in uniform contact with the entire outer peripheral surface of the cylindrical member 8, and grips the cylindrical member 8 with a high tightening force due to formation by HIP processing. On the other hand, the intermediate layer 3 is diffusion bonded to the outer cylinder member 7 by HIP processing,
Metallurgically integrated. Therefore, the outer cylindrical member 7 is in uniform contact with the cylindrical member 8 via the intermediate layer 3, and is strongly joined to the cylindrical member 8.

After the HIP treatment, it is slowly cooled, and a cylinder hole 6 is bored along the axial direction in the axial center of the cylindrical member 8 to form the inner cylinder 4. Further, after forming the hopper hole 5 in the outer cylinder member 7,
The outer peripheral surface is uniformly processed to form an outer cylinder 2, and a composite cylinder 1 is obtained.

In the composite cylinder 1 described above, the linear expansion coefficient of the intermediate layer 3 is set larger than that of the outer cylinder 2, as described above. For example, the difference in linear expansion coefficient between the inner cylinder and the outer cylinder is 2 to 5xlO-h.
/'C, it is preferable to adjust the linear expansion coefficient of the intermediate layer to a value that is 3 to 5X10-'/'c larger than the linear expansion coefficient of the outer cylinder. This is because the intermediate layer follows the thermal expansion of the outer cylinder and applies appropriate bonding stress to the inner cylinder.

Although this embodiment describes a composite cylinder installed in an injection molding machine or an extrusion machine, the present invention is not limited to this, and the nozzle or head ring for injection or extrusion molding may be made of a composite of ceramics and metal. It is also applicable when formed as a.

Specific examples will be described below.

■ Made of Cr-Mo steel (JIS SCM440), inner diameter 32 (+0.1~0.2) mmφ, outer diameter 65Mφ
, an outer cylinder member with a length of 750 mm2 was prepared.

(2) A lower liner and a lower cover are fitted to the lower end side of the outer cylinder member, and the lower cover and the outer cylinder member are fixed by welding. Further, an upper liner was fitted to the upper end side of the outer cylinder member.

■ Made of commercially available machinable ceramic. Outer diameter 32m
A cylindrical member having a diameter of 730 mmf and a length of 730 mmf was inserted into the outer cylindrical member (2) above, and was supported concentrically by the upper and lower liners.

■ While vibrating the outer cylinder member with the cylinder member described in ■ above in it using a vibrator, inject metal powder with the composition shown below into the gap between the outer cylinder member and the cylinder member through the powder injection hole in the upper liner. It was filled.

Metal powder composition (unit weight %) Ni: 2.0 to 5.2%, Zr: 0.01
~0.5%Si: 0.5~2.0%, Cr:
0.1-0.5%Co: 0.5-2.0%, -)
: 0.5-1.5% balance is substantially Cu.

At this time, the thickness of the metal powder filled layer was 2.1 mm,
The powder filling ratio was targeted at 0.7.

(2) After filling the powder, a top cover equipped with a degassing pipe was fitted to the upper end of the outer cylinder member and fixed by welding to obtain an intermediate material.

(2) While evacuating the intermediate material obtained above from the degassing tube, the temperature of the intermediate material was raised to 600''C, and the degassing tube was sealed.The ultimate degree of vacuum at this time was 0.005 Torr.

■ Degassed intermediate material at 960″C, 100100O/
CD, for 2.5 hours to form an intermediate layer and diffusion bond the intermediate layer and the outer cylinder member.

■ After slow cooling, a cylinder hole was bored in the cylindrical member.

First, diamond chips or CBN chips (BN
A cylinder hole was formed by deep hole processing (so-called BT^ processing) with a diamond grindstone (#800) and then honing with a diamond grindstone (#800) to an inner diameter of 22 mmφ and a surface roughness of 1.6S Rmax.

■ Next, a part of the hopper is formed by milling, and the outer periphery of the outer cylinder member is uniformly processed to have an inner diameter of 22 mmφ and an outer diameter of 58 mm.
A composite cylinder with numφ and length of 680 mmf was obtained.

(Effects of the Invention) In the manufacturing method of the present invention, an intermediate layer made of metal powder having a coefficient of linear expansion larger than that of the outer cylinder is formed between the outer cylinder and the inner cylinder of the composite cylinder by HIP treatment, so that the inner cylinder can Regardless of the machining accuracy of the outer circumferential surface of the inner cylinder and the inner circumferential surface of the outer cylinder, the entire outer circumferential surface of the inner cylinder is always uniformly and strongly gripped and backed up by the intermediate layer and the outer cylinder. Therefore, according to the present invention, it is possible to manufacture a composite cylinder with high reliability in which accidents such as dislodgement and destruction of the inner cylinder are extremely rare even when used at normal temperatures as well as when used at high temperatures.

In addition, as the outer cylinder and inner cylinder are joined through the intermediate layer formed by HIP processing as described above, it is possible to use ceramic inner cylinders for small diameter cylinders, which has not been practical with shrink fit. This made it possible to manufacture small-diameter composite cylinders.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a main part of a composite cylinder manufactured according to an embodiment of the present invention, and FIG. 2 is an explanatory cross-sectional view of a composite material for manufacturing a composite cylinder according to an embodiment. 1.-Composite cylinder-12-Outer cylinder, 3-.Intermediate layer, 4
-・-Inner cylinder, 6・-Cylinder hole, 7-・Outer cylinder member, 8
-Cylindrical member, 9-metal powder, 15-composite material. Shadow 1:

Claims (1)

[Claims] (1) Method for manufacturing a composite cylinder (1) in which an intermediate layer (3) is formed between a metal outer cylinder (2) forming the cylinder body and an inner cylinder (4) made of a wear-resistant material, which fixes both. A cylindrical member (8) made of ceramic with excellent wear resistance is inserted concentrically into an outer cylindrical member (7) made of a high-strength metal material, and the gap between the two members (7) and (8) is is filled with a metal powder (9) having a coefficient of linear expansion larger than that of the outer cylinder member (7) to form a composite material (15).
5) A method for manufacturing a composite cylinder, characterized in that, after hot isostatic pressing, a cylinder hole (6) is formed in the axial center of the cylindrical member (8) along the axial direction.