JP2680719B2 - Manufacturing method of bimetallic cylinder - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing a bimetallic cylinder excellent in corrosion resistance and wear resistance used in injection molding or extrusion molding of various plastic materials. .

(Prior Art) A method of manufacturing a bimetallic cylinder proposed in JP-A-63-312902 will be described with reference to FIGS. Bimetallic cylinders are filled with corrosion-resistant and wear-resistant alloy powder on the inner wall surface of a screw hole formed in a cylinder body made of one-piece steel, molded by a hot isostatic pressing (hereinafter referred to as HIP) device, and This is a manufacturing method in which sinter is applied, but in the cases of FIGS. 4 to 6, the core is taken out after completion of HIP by coating the core with an inorganic release agent.

That is, in FIG. 5 (and FIG. 6), the cylinder 3
For example, it is made of a steel material such as SCM440, and a pair of holes 5a, 5a into which adjacent screws or rotors are inserted are formed by communicating portions 5b which are parallel to each other in the axial direction and along the axial direction. On the other hand, the single core 2 shown in FIG. 4 uses a metal material having a coefficient of thermal expansion larger than that of the cylinder 3 by at least 4 × 10 ⁻⁶ cm / ° C. or more, such as austenitic stainless steel material. Thus, a gap is generated at the boundary between the inner diameter surface 3a of the cylinder 3 formed by the holes 5a, 5a of the cylinder 3 and the core 2 at room temperature (room temperature).

The cross section of the single core 2 has a cylinder inner diameter surface 3a.
And a pair of columnar portions 2a, 2a having a similar shape to the cross-sectional shape formed by connecting a pair of holes 5a, 5a, and both columnar portions 2a, 2a traversing the communication portion 5b.
And a wall-shaped portion 2b is formed integrally and continuously. The dimensions of the entire surface of the core 2 and the inner surface of the cylinder are
It is assumed that a substantially eyeglass-shaped powder filling space 4 is formed between the space 3a and the space 3a. When the core 2 is inserted, the release agent 1 is coated on the entire outer peripheral surface of the core 2. This is because both the cylinder 3 and the core 2 are made of a metal material,
In addition, since metal powder is used for guarding, diffusion bonding is avoided by a later HIP process, and detachment of the core 2 is facilitated. And the release agent 1 at this time
An aqueous one-pack type paste made of 100% inorganic material is used as a material for the above.

This is to prevent adverse effects on heat. For example, using a paste containing a mixture of (zirconia + pure water + inorganic binder), etc., spray coating the entire outer peripheral surface of the core 2 to a thickness of about 0.3 t, and then hardening at room temperature ( 15 ° C. × 1 Hr), and after checking that the pencil hardness is 4H or more, the single core 2 is concentrically mounted inside the cylinder inner diameter surface 3a. Also HIP
The processing is the same as the conventional usage. After closing both ends of the cylinder 3 in the axial direction, the whole is sealed in a HIP device.
By applying a hot isostatic press under a heating temperature of 150 ° C. and a pressurizing condition of 1000 kgf / cm ² × 4Hr, for example, a Co-based abrasion-resistant and corrosion-resistant alloy powder filled in the space 4 is coated on the inner surface of the cylinder. The lining layer 6 is formed integrally on the 3a side. Next, take out after HIP processing, let it cool down,
Can be easily removed by cutting both ends of the closed core and extruding the single core 2.

(Problem to be Solved by the Invention) Corrosion-resistant and wear-resistant alloy powder for the lining layer formed on the inner surface of the cylinder is filled as in the conventional method, and the core 2
Is coated with an inorganic release agent 1, the lining layer is sintered by HIP processing, the core is taken out by the difference in thermal expansion in the cooling process, and the cylinder inner diameter surface of required dimensions and shape is obtained without cutting. It was necessary to spray coat the core with an inorganic release agent and cure it at room temperature. However, with this coating, it was difficult to obtain a uniform film thickness.

The present invention has been proposed to solve the above-mentioned conventional problems.

(Means for Solving the Problem) For this reason, the present invention is a multi-axis uniaxial or more, the cross-sectional shape is a circular, hexagonal polygonal cylinder inner surface, corrosion and corrosion resistance by hot isostatic pressing method. In a method for manufacturing a bimetallic cylinder for lining a wear material, a core having a coefficient of thermal expansion larger than that of the cylinder base material is used as a core that is inserted into a hole of the cylinder base material to form the space for the lining layer, and black oxide is used. Chemical treatment such as film treatment is applied to form a strong oxide film, followed by hot isostatic pressing.
This is a method in which a core is taken out after forming a gap between the lining layer and the core in the cooling process after the same treatment, and this is a means for solving the problem.

(Function) By inserting a core into the hole formed in the cylinder base material, a space for filling the corrosion-resistant and wear-resistant material is formed, and after filling the space with the corrosion-resistant and wear-resistant material, hot work etc. The material is sealed in a pressure pressurizing device, and the material is sintered and diffusion bonded. Thereafter, if the cylinder base material is cooled to room temperature, the core and the lining layer are easily separated by the stress generated by the difference in thermal expansion between the cylinder and the core, and the core can be removed from the core by extrusion.

(Embodiment) The present invention will be described below based on an embodiment of the drawings. Figs. 1 to 3 show an embodiment of the present invention, in which 11 is a core and a pair of left and right first and second cores. 11a, 11b are in the shape of spectacles that are joined at the facing surface, a similar hole 12a into which the core 11 is inserted is opened in the cylinder 12, and a metal powder is provided between the core 11 and the hole 12a. A filling space 13 is formed. The material of the core 11 is a material having a coefficient of thermal expansion larger than that of the material of the cylinder 12 (for example, steel material such as S25C).
By performing a chemical treatment such as black oxide film treatment on the surface of 11 to form a strong oxide film, the diffusion phenomenon of atoms is inhibited, and the lining layer 14 between the cylinder 12 and the space 13 is filled. Core 11 and lining layer rather than diffusion bond strength
The gap between the core 14 and the core 11 becomes weaker, and a gap is generated at the boundary between the lining layer 14 and the core 11 at room temperature during the cooling process. For example, S25C is used for the material of the cylinder 12, and the core 11 is subjected to black oxidation treatment with the core material being austenitic stainless steel (for example, SUS304) having a thermal expansion coefficient larger than that of the cylinder 12.

As the black oxidation treatment method, for example, the core 11 is first degreased, and then the current density is about 30 A / dm ^{2 in a} phosphoric acid solution.
Electrolytic polishing is carried out at a temperature of about 2 minutes. Next, the surface is activated in a hydrochloric acid solution at room temperature for about 1 minute, and then immersed in a caustic soda solution of the main component at 130 to 140 ° C. for 1 to 3 minutes. It is then neutralized by immersion in a 0.3% solution of chromic anhydride for about 30 seconds. Then it is dried. By this treatment, the iron oxide film 15 of about 1 to 2 μm is formed.

This core 11 is inserted into the cylinder 12, the metal powder filling space 13 is filled with, for example, Ni-based corrosion-resistant, wear-resistant alloy powder,
Then, after closing both ends in the axial direction, vacuuming is performed and the whole is put in the HIP device. For example, heating temperature of 930 ° C, 1200 kg
The lining layer 14 is formed by hot isostatic pressing under f / cm ² × 3 Hr press condition. See also Naka 11
The oxide film 15 formed by the black oxidation treatment on is very stable and does not disappear during the HIP treatment, or the oxide film is broken due to the deformation of the bonding interface, and some clean surfaces are exposed and bonded. Produce points.

However, since the area of the joined portion is small, the joining strength is small, and due to the difference in the thermal expansion coefficient between the core 11 and the cylinder 12 during the cooling process after HIP treatment to room temperature, the core 11 and the lining layer 14 are A very large stress is generated in the vicinity of the interface of, so that even if the oxide film is partially broken, the bonding area is small and the bonding strength is small, so the neutralization 11 and the lining layer 14 easily separate during the cooling process. .

Then, by cutting both ends in the axial direction, the core 11 can be removed from the mold by extrusion. A lining layer having uniform corrosion resistance and wear resistance is formed on the inner surface of the cylinder 12. In addition, by setting the dimensions and the cross-sectional shape in consideration of the difference in thermal expansion in advance, it is possible to manufacture the highly accurate cylinder inner diameter surface only by light polishing without cutting after demolding.

(Effects of the Invention) As described in detail above, the present invention uses a material having a coefficient of thermal expansion larger than that of the cylinder base material for the core, and performs chemical treatment such as black oxide film treatment on the surface. Compared to the method of coating the core with an inorganic release agent and removing the core after HIP, a uniform film can be formed, so that a highly accurate cylinder inner diameter surface can be manufactured.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of a core used in the method of the present invention, FIG. 2 is a front sectional view showing a state in which the core of FIG. 1 is set in a hole of a cylinder, and FIG. FIG. 4 is a front sectional view showing a state where a core is taken out after formation, FIG. 4 is a perspective view of a core used in a conventional method, and FIG. 5 is a front view showing a state where the core is inserted into a hole of a cylinder. FIG. 6 is a front sectional view showing a state in which the core of FIG. 5 is taken out after the lining layer is formed. Description of main parts of the figure 11 …… Core 11a …… 1st core 11b …… 2nd core 12 …… Cylinder 12a …… Hole 13 …… Space for metal powder filling 14 …… Lining layer 15 …… Oxidation Film

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Haruo Katsuno No. 1 Takamichi, Iwazuka-machi, Nakamura-ku, Nagoya, Aichi Prefecture Mitsubishi Heavy Industries, Ltd. Nagoya Machinery Works (72) Inventor, Kazuyuki Tanaka, Iwazuka, Nakamura-ku, Nagoya, Aichi Prefecture Mt. Takadō No. 1 Mitsubishi Heavy Industries, Ltd. Nagoya Machinery Works (56) References JP-A-2-194107 (JP, A) JP-A-3-61306 (JP, A) JP-A-63-312902 (JP , A)

Claims (1)

(57) [Claims] (1) a multi-axis of one or more axes and a circular cross section;
In the method of manufacturing a bimetallic cylinder in which a hexagonal polygonal cylinder inner surface is lined with a corrosion-resistant and wear-resistant material by the hot isostatic pressing method, the space for the lining layer is formed by inserting it into the hole of the cylinder base material. For the core to be formed, a material with a coefficient of thermal expansion larger than that of the cylinder base material is used, chemical treatment such as black oxide film treatment is applied to form a strong oxide film, and then hot isostatic pressing is performed. A method for producing a bimetallic cylinder, characterized in that a core is taken out after a gap is created between the lining layer and the core in the cooling process after the treatment.