JPS59189976A - Lining method for hollow pipe - Google Patents

Abstract

PURPOSE:To easily manufacture a hollow pipe having suitable wear and corrosion resistance, etc., by charging a lining material in a hollow pipe, hermetically sealing said pipe in an unoxidizing atmosphere, heating it, and then rotatively cooling it. CONSTITUTION:A lining material in a powdery or cluster state is charged in a hollow pipe, and the interior of said hollow pipe is held in an unoxidizing atmosphere such as an inert or vacuum one and hermetically sealed f to isolate it from the open air. Thereafter, the hollow pipe is heated g pref. under a stationary condition to melt the lining material, rotated h to perform centrifugal casting and then cooled i. Hence, the hollow pipe having the treated inner surface is easily manufactured at a low cost.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hollow tube lining method used for lining the inner surface of a hollow tube, such as a cylinder for a resin molding machine, with a wear-resistant and corrosion-resistant alloy.

Examples of parts that require wear resistance and corrosion resistance include resin molding machines, mortar pumps, slurry pumps,
There are cylinders used in compressors, etc.

On the other hand, glass fiber and carbon fiber are included in the resin molded body.

By mixing reinforcing materials such as metal fibers, the strength of the resin molded body,
In recent years, attempts have been made to improve the properties of materials such as flame retardancy and abrasion resistance. Therefore, the cylinder part of a resin forming machine is required to have stricter characteristics than before, such as less wear due to reinforcing materials and additives added to the resin, and less corrosion due to gases emitted from the resin and additives. has been done.

By the way, in cylinders in conventional resin molding machines, cylinder parts are molded from nitrided steel using the BTA method using a deep hole drill, and then the inner surface of the cylinder is nitrided and hardened to provide wear resistance to the surface. I was trying to grant it.

However, although this nitrided cylinder has excellent surface wear resistance, it has poor corrosion resistance.
In particular, when exposed to strong corrosive and abrasive environments, such as special resin cylinders for injection molding machines and cylinders for mortar pumps, they have the disadvantage of short service life.

Therefore, there has been a strong desire to develop a new alloy that is both corrosion resistant and wear resistant and inexpensive. Several new alloys have been developed based on this request, but they are all expensive, and it is said that their use alone as a material for cylinder parts is economically undesirable because it reduces the manufacturing cost of the cylinder. It had some problems.

Therefore, the conventional method to solve these problems is as follows.
A method has been considered in which the inner surface of the cylinder is lined with a wear-resistant and corrosion-resistant alloy by thermal spraying or overlay welding. However, in this method, 4'1. ! The inner diameter of the resin cylinder for the copper mine forming machine is small at about 25 to 50 mm, and if it is long (300 to 1200 mm), it is necessary to insert a torch into the inner diameter part and perform thermal spraying or overlay welding, so the work is difficult. The problem was that it was difficult and complicated.

This invention was made to solve these conventional problems, and the inside of a hollow tube charged with a lining material in the form of powder or chunks is heated to a non-oxidizing atmosphere such as an inert atmosphere or a vacuum atmosphere. The lining material is melted by heating in an atmosphere, and then the hollow tube is rotated and centrifugally cast, whereby the inner surface is lined with a wear-resistant and corrosion-resistant alloy suitable for, for example, cylinders for special resin injection molding machines. The aim is to provide a hollow tube lining method that allows hollow tubes to be manufactured easily and at low cost9.
It is said that

That is, the method for lining a hollow tube according to the present invention is as follows:
When lining the inner surface of a hollow tube, a lining material in the form of powder or chunks is charged into the hollow tube, and the inside of the hollow tube is made into a non-melting atmosphere such as an inert atmosphere or a vacuum atmosphere. After the hollow tube is sealed and isolated from the outside air, the hollow tube is preferably heated in a stationary state to melt the lining material, and then rotated and centrifugally cast, and then cooled.

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

1 and 2 are process block diagrams showing an example of the hollow tube lining method according to the present invention, and explanatory diagrams showing the cross-sectional state of the hollow tube in the main steps of FIG. , 1 is a metal hollow tube such as a cylinder base injection, 2 is a pellet-like lining material lining the inner wall surface of the metal hollow tube 1, and 3 is a sealing lid.

The metal hollow tube 1 is molded, for example, from carbon steel by the BTA method using a deep hole drill, and serves as a cylinder main tube when manufacturing cylinder parts for injection molding machines of special resin. The inner diameter d of the metal hollow tube 1 is 1.0 mm larger than the inner diameter d2 of the lining hollow tube 4, for example, a cylinder part, shown in FIG.
It is formed to have an extremely large diameter (see FIG. 2(a)).

On the other hand, the lining material 2 is, for example, Co-Cr-Ni −
It is made into pellets by melting wear-resistant and corrosion-resistant alloys such as B-based self-fluxing alloys in a melting furnace, such as an electric furnace or a high-frequency induction furnace, and is used as a material for lining the inner wall surface of the hollow metal tube 1. It is used.

Next, this pellet-shaped lining material 2 is applied to the inner wall surface of the metal hollow tube 1 to a predetermined thickness of 1. Weigh out the amount necessary for lining, and charge this amount into the metal hollow tube l. Then, with the pellet-like lining material 2 charged into the hollow metal tube 1, the inside of the hollow metal tube 1 is made into a non-oxidizing atmosphere such as an inert atmosphere or a vacuum atmosphere, and both ends of the tube are covered with electrically closed lids 3. Block it with At this time, as a method to make the inside of the metal hollow tube 1 a non-oxidizing atmosphere, after charging the pellet-shaped lining material 2 into the metal hollow tube 1,
The air inside is replaced with argon (Ar) gas, and both ends are closed with airtight lids 3 (see FIG. 2(b)). More preferably, the pellet-shaped lining material 2 is charged into the metal hollow tube 1 and both ends thereof are closed with sealing M3, and then a vacuum pump is inserted through a suction port (not shown) provided in one of the sealing lids 3. The pressure is reduced to create a vacuum inside the metal hollow tube 1, and then the suction port is closed.

Next, in this way, create a non-oxidizing atmosphere.
For example, in the case of the Co-Cr-N1-B self-fluxing alloy, the metal hollow tube 1 is charged into a furnace heated to about 1200°C,
This furnace is kept in the furnace for a predetermined period of time, and the pellet-shaped lining material 2 inside the metal hollow tube 1 is melted in an inert atmosphere or a vacuum atmosphere. After a predetermined period of time has elapsed, the metal hollow tube l is taken out of the furnace and immediately attached to a centrifuge (not shown), the centrifuge motor is started, and centrifugal casting is started at a predetermined rotational speed. 2 [see Δ(C)). In order to apply centrifugal force during centrifugal casting, either a horizontal axis or a vertical axis can be used as the rotation direction, but in the case of a small diameter and long cylinder part, as shown in Fig. 2 ( It is preferable to use the horizontal axis as shown in C). The rotation by this centrifuge is 8 times
Continue until cooled to 00°C, at which point stop the centrifuge motor. Thereafter, the metal hollow tube 1 is slowly cooled to room temperature.

Next, the metal hollow tube 1 is cut to a predetermined length as a cylinder component, the sealing lid 3 is removed, and the metal tube 1 is cut into a predetermined length as a cylinder component, and the sealing lid 3 is removed, as shown in FIG. 2(d).
As shown in FIG. 2, the surface of the lining 5 is subjected to a grinding finish such as honing to obtain the lined hollow tube 4.

As described above, in the method for lining a hollow tube such as a cylinder according to the present invention, a lining material 2 such as a pellet is melted in the hollow tube 1 in a non-oxidizing atmosphere such as an inert atmosphere or a vacuum atmosphere. Since the material used for the lining 5 is then taken out of the furnace and centrifugally cast, it is not oxidized, and the centrifugal force applies a large static pressure to the inner wall surface of the hollow metal tube l for diffusion welding, resulting in a uniform and strong weld. This results in a lining layer.

Furthermore, since the reinige material is centrifugally cast and solidified while sealed in the metal hollow tube 1, the inside of the metal hollow tube 1 is kept warm, and gradually starts from the outer periphery of the metal hollow tube 1. cooled down. This means that directional solidification is possible because the lining material 2, such as a self-fluxing alloy, diffusion-welded to the inner wall surface of the hollow metal tube 1 is cooled from the outer circumferential side of the hollow metal tube 1 and gradually solidifies. This means that there are no shrinkage pores that occur during solidification.

5 Next, one embodiment of the present invention will be described.

First, a Co-based wear-resistant alloy having the chemical components shown in the table was remelted at 1480'C in an electric furnace to create a self-fluxing alloy in the form of pellets.

Next, this self-fluxing alloy was made into an outer diameter of 100 mm, an inner diameter of 32 mm,
After filling a cylinder with a length of 1000 mm (71 carbon 611! (SC)) with the amount necessary to line the inner wall of the cylinder with a thickness of 3 mm on one side, the inside of the cylinder was filled with argon (Ar) gas. After that, the cylinder was replaced with carbon steel and its ends were sealed with carbon steel cloth lids, and then placed in a furnace at about 1200°C and heated, and after the self-fluxing alloy was melted by heating, the cylinder was taken out from the furnace. The cylinder was mounted on a centrifuge and cooled to 800°C while rotating, and then gradually cooled to room temperature.Then, the cylinder was cut to a predetermined length and finished by cutting to produce the desired cylinder part. .

4U cylinder parts! When I observed the inside of the product,
It was found that the J wear and corrosion resistant layer was uniformly formed and had almost no shrinkage pores. Furthermore, in cutting the inner surface of the cylinder, it was confirmed that the machinability was good despite the hardness of the surface.

As explained above, according to the present invention, when lining the inner surface of a hollow tube, a lining material in the form of powder or chunks is charged into the hollow tube, and the inside of the hollow tube is kept in an inert atmosphere. Alternatively, after creating a non-oxidizing atmosphere such as a vacuum atmosphere and sealing the inside to isolate it from the outside air, the hollow tube is heated and the lining material is melted. Applications that require wear and corrosion resistance, such as cylinders for mortar pumps. This method has the remarkable effect that hollow tubes suitable for the following applications can be manufactured easily and at low cost.

[Brief explanation of the drawing]

FIG. 1 is a process block diagram showing an embodiment of the hollow tube lining method according to the present invention, and FIGS. 2(a) to (d) are cross sections of the hollow tube showing states in the main steps of FIG. It is a diagram. l...Hollow tube, 2...Lining material, 3...Closing lid, 4...Lining hollow saving, 5...Lining. Patent Applicant: Daido Hekushuko Co., Ltd. Representative Patent Attorney Yutaka Oshio Figure 1-420- Figure 2

Claims (1)

[Claims] (1) When lining the inner surface of a hollow tube, a lining material in the form of powder or chunks is charged into the hollow tube, and the inside of the hollow tube is kept in an inert atmosphere or vacuum atmosphere, etc. The lining of the hollow tube is characterized in that the hollow tube is heated to melt the lining material after the inside thereof is made into a neutral atmosphere and isolated from the outside air by using cloth, and then the hollow tube is rotated and centrifugally cast to be cooled. Method.