JPH04337009A - Production of composite different-diameter tubular body - Google Patents

Abstract

PURPOSE:To produce the above tubular body by using a solid core made by molding machinable ceramics, packing metallic powder into a spacing to can the core, then subjecting the core to an HIP treatment (hot isostatic pressurization treatment) and boring the core with a drill. CONSTITUTION:The solid core 4 molded of the machinable ceramics is inserted into the hollow part 2 of a shell base body 1 having a hollow part 2 and the metallic powder body 5 is packed into the spacing between the inside surface of the hollow part 2 of the shell base body 1 and the outside surface of the solid core 4 to can the base body; thereafter, the base body is subjected to the HIP treatment. The solid core 4 is thereafter bored with a tool, such as drill, and the remaining core is removed by collapse, by which the composite different-diameter tubular body is obtd.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention provides corrosion resistance for plastic injection molding machine nozzles, synthetic resin pipes, crosshead dies for tube extrusion molding machines, straight dies, etc.
The present invention relates to a method for manufacturing a composite pipe body of different diameters, which is a component that requires wear resistance.

0002

[Prior Art] For example, in the case of a nozzle for a plastic injection molding machine, it is usually made of nitrided steel or tool steel, which is annealed and processed into a desired different inner diameter in a relatively soft state, and then nitrided or hardened. - It was hardened by tempering to give it wear resistance.

However, the durability of reinforced plastic molding in recent years is insufficient, and the use of composite nozzles whose inner surfaces are HIP-lined with Ni-based/Co-based wear-resistant alloys is increasing. As a method for manufacturing a composite nozzle whose inner surface is HIP-lined with the Ni-based/Co-based wear-resistant alloy, for example, the method described in JP-A-61-186406 is known.

This known method involves inserting a pressure-guiding metal tube into the inner surface of the outer shell base, filling the gap defined by the inner surface of the outer shell base and the outer surface of the metal tube with metal powder, and then canning. After that, by performing HIP treatment (hot isostatic pressing treatment), an inner shell body made of sintered alloy is formed in close contact with the inner surface of the outer shell base body, and then the outer shell base body and the inner shell body are machined. was applied to finish it into a predetermined shape.

[0005]

[Problems to be Solved by the Invention] However, in the conventional lining forming method using the HIP method, it is not possible to form the inner surface into a net shape with different diameters, and since the material is highly hard and difficult to cut, it is difficult to form the lining by machining. This process requires many steps and a long time. Therefore, in contrast to the trend toward high hardness lining properties to improve wear resistance, there is a need for lining materials that are easy to machine at the expense of high hardness. The reality is that there are restrictions on the lining material.

[0006] Furthermore, in the conventional method, since machining is required, there is a problem in that the shape of the inner surface with different diameters is limited to a shape that can be machined. Due to the above-mentioned restrictions, improvement of the injection or extrusion function related to the shape of the inner diameter of the nozzle or die (crosshead die, straight die) has been hindered. Therefore, an object of the present invention is to provide a method for manufacturing a composite tube with different diameters by the HIP method, which does not depend on machining and allows net shaping.

[0007]

[Means for Solving the Problems] In order to achieve the above object, the present invention has taken the following measures. That is, the feature of the method for manufacturing a composite tube with different diameters of the present invention is that a solid core formed from a machinable ceramic material is inserted into the hollow portion of an outer shell base having a hollow portion, and After filling the gap between the inner surface of the hollow part of the shell base and the outer surface of the solid core with metal powder and canning, HIP treatment was performed, and then the solid core was drilled with a tool such as a drill. After that, the remaining core is disintegrated and removed to obtain a composite tube with different diameters.

[0008]

According to the present invention, the inner diameter of parts such as nozzles and dies having different inner diameters depends on the outer peripheral shape of the solid core. Since machining of the outer peripheral shape of the solid core is easy, it is possible to manufacture parts having complicated inner diameters of different diameters. Since this solid core is made of ceramic, it does not undergo diffusion bonding with the metal lining material, so there is no need for a mold release agent used in ordinary metal cores, and it can be disintegrated and removed by drilling.

Furthermore, since the ceramic core is made of a machinable ceramic material close to the outer shell base (steel), the inner diameter of the finished part can be formed into a highly accurate net shape.

0010

EXAMPLE A method of manufacturing a nozzle capsule as an example of a composite tube with different diameters will be explained with reference to FIGS. 1 and 2. First, a hollow part 2 is provided in a body part 1 of a nozzle body serving as an outer shell base, and an opening at one end of this hollow part 2 is closed by welding with an upper lid 3.

On the other hand, the solid core 4 to be inserted into the hollow portion 2 is made of machinable ceramics. The outer diameter of the core 4 is determined by subtracting the diameter increase due to thermal expansion when the HIP treatment temperature (900 to 1000° C.) is reached from room temperature to the desired drawing dimension. The solid core 4 is a free-cutting ceramic that has a thermal expansion (between R.T. and 960°C) of 8 to 9 x 10-6 cm/°C, which is close to that of metal, and can be machined, and is also strong in terms of strength. Excellent commercially available machinable ceramics are used.

The surface roughness of the solid core 4 is polished to 0.1S, which is the desired drawing specification. Next, the solid core 4 is inserted into the hollow part 2 of the body part 1 of the nozzle body, and the gap between the inner surface of the hollow part 2 and the outer surface of the solid core 4 is filled with metal powder 5, After that, hollow part 2
The other opening is closed by welding with the lower lid 6. At this time,
Both ends of the solid core 4 are positioned by fitting into spigot parts 7 and 8 formed on the upper and lower lids 3 and 6. Then, the air in the hollow portion 2 is degassed through a deaeration pipe 9 formed in the lower lid 6, and after that, the deaeration pipe 9 is closed and sealed to complete the canning operation, and then the whole is subjected to HIP processing. Through this HIP process, the metal powder is sintered to form a lining layer 10 on the inner surface of the hollow part 2.

[0013] This HIP treatment is carried out at 960°C and 100°C.
After holding at 0 kgf/cm2 for 3 hours, the furnace was cooled. After the HIP treatment, the upper and lower lids 3 and 6 at both ends of the body 1 of the nozzle body are cut and removed to expose both ends of the solid core 4, and then from both ends to the vicinity of the minimum diameter part,
A hole is made in the solid core 4 using a pilot hole drill smaller than the inner diameter of the finished product. Then, for the remainder of the core 4 remaining after drilling,
By applying vibration and light impact, the lining layer 10
to fall off.

Thus, the inner surface of the lining layer 10 became the inner surface of the nozzle, the inner diameter of the nozzle was formed into a net shape, and the surface roughness was equivalent to 0.3S. Specific examples will be described below. The materials of each component are as follows. ■ Outer shell base ~ JIS-SCM440 (chromium molybdenum steel) ■ Machinable ceramics (standard structure)
~K2O; 9.5wt%, MgO; 14.
5”, F; 6.3”, Al2 O3; 1
6.7", B2 O3; 8.5",
SiO3; 47.2” ■ Metal powder (one example) ~17.5wt%Cr,
24.0wt%Mo, 3.6wt%B, 2.
9wt%Si, 1.0wt%Cu, Bal
The conditions for disintegration and removal of the core (machinable ceramics) by Ni drilling are as follows.

That is, the test is carried out using a general-purpose carbide drill under the following conditions. a) Cutting speed: 10m/min or more (standard 15
m/min) b) Feed; 50mm/min
n or more (standard 60mm/min) c) Depth of cut
; - e) Cutting fluid; Unnecessary (dry method) By drilling under conditions higher than that, the core was able to disintegrate and be removed.

The present invention is not only applicable to the method for manufacturing the nozzle capsule, but also applies to, for example, tapered inner diameter uniaxial and biaxial cylinders, nozzles for biaxial cylinders, and crossheads for pipe/tube extrusion molding machines. The present invention can be applied to methods for manufacturing composite tubes with different diameters, such as dies, straight dies, and inflation dies (spiral dies) for blown film forming machines.

[0017]

According to the present invention, the inner diameter of parts such as nozzles and dies having different inner diameters can be manufactured by using a solid core. This solid core can be machined, and since it is made of ceramic, it does not undergo diffusion bonding with the metal lining material during HIP processing, and does not require a mold release agent that is used in ordinary metal cores. In addition, since the ceramic core is similar to that of the capsule body (steel), the inner diameter can be molded into a highly accurate net shape.

Furthermore, after HIP forming, the solid core can be disintegrated and removed by drilling a pilot hole smaller than the inner diameter of the finished product.
Cutting, electrical discharge machining, etc. are not required after HIP. Therefore, it is possible to manufacture inner diameters with different diameters that are subject to processing restrictions, and the nozzle and die extrusion functions can be improved.

[Brief explanation of drawings]

[Figure 1] HIP of nozzle capsule as a composite tube with different diameters
It is a sectional view before processing.

FIG. 2 is a cross-sectional view of the nozzle capsule from which the core has been removed after HIP treatment.

[Explanation of symbols]

1 Outer shell base (body of nozzle body) 2 Hollow part 4 Solid core 5 Metal powder

Claims (1)

[Claims] Claim 1: A solid core molded from a machinable ceramic material is inserted into the hollow part of an outer shell base, and the inner surface of the hollow part of the outer shell base is connected to the outer surface of the solid core. After filling the gap with metal powder and canning, HI
Manufacturing a composite different diameter tube body, characterized in that the solid core is subjected to P treatment, and then the solid core is drilled with a tool such as a drill, and then the remaining core is collapsed and removed to obtain a composite different diameter tube body. Method.