JPH07125095A - Manufacture of resin lined steel pipe with flange - Google Patents

Abstract

PURPOSE:To make superior the bonding properties between a main body lining layer and a flange lining layer, and prevent the generation of peeling off or the like between them due to the heat shrinkage of the like. CONSTITUTION:A bonding section between a flange resin lining layer 7 and a main body resin lining layer 3b is heated up to the resin melting temperature by a heating means 8, and the flange resin lining layer 7 is bonded securely and firmly with the main body resin lining layer 3b at the bonding section.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a resin lining steel pipe with a flange by lining a resin from the inner surface of the flanged steel pipe having a flange for joining to the pipe end to the pipe end.

[0002]

2. Description of the Related Art A flanged steel pipe used as a piping material integrally provided with a flange at the end of a steel pipe body is provided with a resin from the inner surface of the steel pipe body to the pipe end flange surface for the purpose of enhancing its corrosion resistance. There is a lining. When such a flanged resin-lined steel pipe is manufactured, if there is a resin-free portion from the inner surface of the pipe end portion to the flange surface, corrosion may progress from that portion during use. Therefore, in manufacturing, it is necessary to form the lining layer so that the resin exists without interruption not only on the inner surface of the steel pipe but also from the inner surface of the pipe end portion to the flange surface.

Therefore, conventionally, a resin pipe longer than the steel pipe body is inserted into the steel pipe, the resin pipe is expanded to line the inner surface of the steel pipe with the resin pipe, and the end portion of the resin pipe is A method in which the flange is returned along the pipe end flange surface (see, for example, JP-A-49-99370), or a method in which the resin tube is simultaneously expanded and the flange portion is integrally expanded (for example, JP-A-54-54).
A resin-lined steel pipe with a flange is manufactured by, for example, Japanese Patent No. 29382).

[0004] However, in the conventional manufacturing method using the above-described flanged work, after heating and softening the end portion of the resin pipe for inner surface lining inserted into the steel pipe with flange, the portion is subjected to the above-mentioned treatment. As described above, the flange is worked so as to be in close contact with the pipe end flange surface. Therefore, among thermoplastic resins, it is applicable to resins having relatively good elongation and excellent workability such as hard vinyl chloride resin, but resins called engineering plastics that have a high melting point and are difficult to extend, such as polyvinylidene fluoride. It is not applicable or extremely difficult to apply to resins such as (PVDF), polyphenylene sulfide (PPS) and polyether ether ketone (PEEK).

Moreover, residual stress is generated in the flange portion,
The resin may peel off from the steel pipe body or flange due to thermal expansion and contraction during use. Also, it is difficult to make the dimensions such as wall thickness and outer diameter of the flange part constant,
A lot of time is required for finishing.

[0006]

Therefore, the applicant of the present invention has previously proposed the following method for producing a resin lining steel pipe with a flange (Japanese Patent Application No. 5-75759).
issue). That is, this manufacturing method, as shown in FIG.
First, the flanged steel pipe 100 in which the flange 102 is integrally provided at the end of the steel pipe main body 101 and the main body resin lining layer 104 is formed on the inner surface of the steel pipe main body 101 is prepared. The main body resin lining layer 104 is the steel pipe main body 1
01 After applying the adhesive 103 to the inner surface, the steel pipe body 10
A synthetic resin pipe slightly shorter than 1 is inserted into the steel pipe main body 101, and the steel pipe main body 101 and the synthetic resin pipe are bonded and integrated with each other via an adhesive 103.

Next, the core mold 105 having substantially the same diameter as the inner diameter of the main body resin lining layer 104 is attached to the main body resin lining layer 1
04 is inserted from the end of the steel pipe main body 101 so as to be fitted to the front end thereof, and an injection molding die 106 is set on the end of the flanged steel pipe 100. Then, as shown in FIG. 10, the resin heated and melted to a predetermined temperature is used for the cavity 107.
The steel pipe main body 10 is injected into the steel pipe and solidified by cooling.
The flange resin lining layer 108 which is connected and integrated with the main body resin lining layer 104 is formed by injection molding from the inner surface of one end portion to the surface of the flange 102.

According to this method, it is not necessary to rework the end portion of the inner surface lining resin pipe. Therefore, as with the engineering plastics such as PPS described above, the lining is difficult because it has difficult physical properties such as dimensional stability, heat resistance, chemical resistance, etc. The resin that could not be used as a raw material can be used, and by doing so, it is possible to manufacture various types of flanged resin-lined steel pipes having excellent performance by utilizing the physical properties of the resin.

However, the above-mentioned manufacturing method proposed by the present applicant has the following problems. That is, since the flange resin lining layer 108 is formed by injecting the molten resin, the main body resin lining layer 104 is melted at a portion in contact with the molten resin and melted at the interface with the flange resin lining layer 108. However, due to the flow of the resin, the fusion may be partially insufficient, and the thermal expansion and contraction of the resin at the insufficient portion may cause peeling at the interface between the two, which may result in insufficient corrosion protection. There is.

In view of the above problems, the present invention is excellent in the bondability between the main body resin lining layer and the flange resin lining layer, and peels off at the interface between the main body resin lining layer and the flange resin lining layer due to expansion and contraction. An object of the present invention is to provide a method for producing a resin lining steel pipe with a flange that does not occur.

[0011]

In order to achieve the above object, a method of manufacturing a resin-lined steel pipe with a flange according to the present invention is directed to a steel pipe body, a flange provided at an end of the steel pipe body, and a steel pipe body. In a flanged steel pipe having a main body resin lining layer covering the wall surface to the vicinity of the pipe end, a flanged resin lining steel pipe including a step of forming a flange resin lining layer from the flange surface to the main body resin lining layer by injection molding The manufacturing method comprises a step of heating the joint between the flange resin lining layer and the main body resin lining layer to a resin melting temperature by a heating means.

In the above structure, the method of providing the resin lining layer on the steel pipe body is not particularly limited. For example, after applying an adhesive to the inner peripheral surface of the steel pipe body, a synthetic resin pipe shorter than the steel pipe body is used. There is a method of inserting it inside and integrating it with the steel pipe body. Examples of heating means for heating the main body resin lining layer and the flange resin lining layer until they melt include a heating plate, a high frequency dielectric heating device, an ultrasonic heating device, a high frequency induction heating device, and the like.

As the resin forming the lining layer, vinyl chloride resin, polyvinylidene fluoride (PVDF), polyphenylene sulfide (PPS), polyether ether ketone (PEEK), fluororesin (eg PV
DF) and the like. Further, the flanged steel pipe includes not only those in which the flanges are provided at both ends of the steel pipe body, but also those in which the flange is provided only at one end of the steel pipe body.

In addition to the above structure, it is preferable that the inner peripheral edge of the end of the main resin lining layer is cut out in a step shape or a taper shape. In the case of notching in a step shape, the length of the parallel part of the step is preferably 5 mm or more. The thickness of the step depends on the thickness of the main body resin lining layer,
When the thickness of the main body resin lining layer is 2 mm or less, it is preferably half or more of the thickness, and when the thickness of the main body resin lining layer is more than 2 mm, it is preferably about 1 to 3 mm within a range not exceeding half the thickness. .

Further, in the case of notching in a taper shape, it is preferable that the taper is 60 ° or less, particularly 45 ° or less from the steel pipe main body side toward the inner wall surface of the main body resin lining layer.

[0016]

According to the above construction, the injection molding die is set at the pipe end of the flanged steel pipe having the main body resin lining layer formed up to the vicinity of the end, and the flange resin lining layer is continuously connected to the main body resin lining layer by injection molding. By this injection molding, since the main body resin lining layer is melted by the injected molten resin, the obtained flange resin lining layer is substantially fused at the main resin lining layer and its joint portion. There is.

Then, the joint portion is further heated by the heating means to melt both resin lining layers and then cooled,
Both resin lining layers are joined more firmly and reliably. Further, if the inner peripheral edge of the end of the main resin lining layer is cut out in a stepped shape or a tapered shape, it is possible to secure a large area of the bonding interface between the main resin lining layer and the flange resin lining layer.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the drawings showing the embodiments thereof. 1 to 4 show a first method of manufacturing a resin-lined steel pipe with a flange according to the present invention.
Examples are shown in the order of steps. That is, the method of manufacturing the resin lining steel pipe with a flange is performed in the following process order.

As shown in FIG. 1, first, the steel pipe body 1
A flanged steel pipe 1 in which flanges 12 and 12 are integrally provided at both ends of 1 is prepared, and an adhesive 13 is applied to an inner surface of a steel pipe body 11 of the flanged steel pipe 1. The synthetic resin pipe 3a is inserted in the direction of the arrow and integrated with the steel pipe body 11 via the adhesive 13. In addition, synthetic resin pipe 3
a is slightly shorter than the steel pipe body 11.

Therefore, by bonding and integrating the synthetic resin pipe 3a with the steel pipe main body 11, as shown in FIG. 2, the main body resin lining layer 3b is formed except for the steel pipe main body end portion 14 in the vicinity of the flange 12. . As shown in FIG. 3, an injection molding die (flange type) 6 having the same axis as the pipe axis of the steel pipe main body 11 is attached to the end of the flanged steel pipe 1, and the core die 5 is attached to the main body resin lining layer 3b. Fit the end of.

Molten resin is injected into the cavity 62 from the resin injection port 61 to form the flange resin lining layer 7. As shown in FIG. 4, the hot platen (fusion head) 8 inserted from the pipe end is pressed against the joint between the flange resin lining layer 7 and the main body resin lining layer 3b, and at the joint,
Flange resin lining layer 7 and main body resin lining layer 3
The resin of b is melted, and both the lining layers 3b and 7 are more firmly fused at their joints.

In the method for manufacturing the resin lining steel pipe with a flange, as described above, the bulging lining layer 7 is molded by injection molding, and then the joint surface between the main body resin lining layer 3b and the flange resin lining layer 7 is heated by a heating means. By heating to a molten state, both the lining layers 3b and 7 can be more firmly fused at their joint surfaces.

Therefore, the flange lining layer 7 and the main body lining layer 3b are firmly integrated with each other, so that peeling or the like does not occur at the interface due to thermal expansion and contraction, and the flanged resin lining steel pipe always has sufficient strength and corrosion resistance. Can be provided. Of course, after the main body resin lining layer 3b is formed, the flange resin lining layer 7 is formed separately by injection molding from the inner surface of the unlined portion of the steel pipe body 11 to the surface of the flange 12, so that the inner surface of the steel pipe body 11 is formed. To the surface of the flange 12 at the pipe end, the resin lining layer is formed without interruption.
Therefore, the end of the resin pipe for the inner surface lining of the steel pipe is flanged as in the past, or the resin short pipe is bonded to the resin pipe with an adhesive and then the end is flanged. Even without doing so, the resin is surely lined from the inner surface of the steel pipe body 11 to the flange 12 surface of the pipe end,
It is possible to manufacture a resin lined steel pipe with a flange even when using a resin that has a high melting point and is difficult to stretch, which makes it difficult to apply a collar and use an adhesive.

In other words, polyvinylidene fluoride (PVDF) and polyphenylene sulfide (PP) are used as the lining material for the resin lining steel pipe with flange.
Resins having excellent physical properties such as S) and polyether ether ketone (PEEK) can be used, and products having excellent performance (for example, dimensional stability) can be obtained.

FIGS. 5 and 6 show a second embodiment of a method for manufacturing a resin lining steel pipe with a flange according to the present invention in the order of steps. In this embodiment, as shown in FIG. 5, a step portion 32 is formed by cutting out the inner peripheral surface of the main body resin lining layer 3b at the end portion in a step shape. Therefore, as shown in FIG. 6, the flange resin lining layer 7 is formed by injection molding as in the first embodiment.
By forming, the area of the joint portion between the flange resin lining layer 7 and the main body resin lining layer 3b increases.

Then, as shown in FIG. 6, the hot platen 8 is pressed against the joint portion to heat the flange resin lining layer 7 and the main body resin lining layer 3b in the joint portion and in the vicinity thereof to make them in a molten state. 3b and 7 can be more firmly fused to each other over a wide area. 7 and 8 show a third embodiment of a method for manufacturing a resin lining steel pipe with a flange according to the present invention in the order of steps.

In this embodiment, as shown in FIG. 7, at the end of the main body resin lining layer 3b, the taper portion 33 is formed by notching the inner peripheral surface of the main body resin lining layer 3b in a tapered shape. Therefore, as shown in FIG. 8, the flange resin lining layer 7 is formed by injection molding as in the first embodiment.
By forming, the area of the joint portion between the flange resin lining layer 7 and the main body resin lining layer 3b increases.

Then, as shown in FIG. 8, the hot platen 8 is pressed against the joint portion to heat the flange resin lining layer 7 and the main body resin lining layer 3b in the joint portion and in the vicinity thereof to be in a molten state. 3b and 7 can be more firmly fused to each other over a wide area.

[0029]

As described above, according to the method for producing a resin lining steel pipe with a flange according to the present invention, the method for producing a resin lining steel pipe with a flange is the same as the method for producing a resin lining steel pipe with a flange previously proposed by the applicant. When lining the part from the inner surface to the pipe end flange surface, the inner surface of the flanged steel pipe is lined with resin, and then the resin lining layer is formed by injection molding on the pipe end of the steel pipe. It is not necessary to perform end-reverse processing on the end of the pipe, or to join the short pipe made of resin to the resin pipe via an adhesive and then perform end-reverse processing on the end of the short pipe.

Therefore, in the case of manufacturing this kind of flanged resin-lined steel pipe, it has excellent physical properties in terms of dimensional stability, heat resistance, chemical resistance, etc., like the engineering plastics such as PPS mentioned above. However, it is possible to use the resin that could not be used as the lining material because it was difficult to process the flange and use the adhesive, and by extension, various flanged resin-lined steel pipes with excellent performance utilizing the physical properties of the resin. Can be manufactured.

Moreover, the joint portion between the main body resin lining layer and the flange resin lining layer is heated by the heating means so that the main body resin lining layer and the flange resin lining layer are
Since it integrates more reliably and firmly by fusion bonding, peeling at the interface between the main body resin lining layer and the flange resin lining layer does not occur due to thermal expansion and contraction,
It is possible to provide a resin lining steel pipe with a flange that always has sufficient strength and corrosion resistance.

If the inner peripheral edge of the end portion of the main body resin lining layer is cut out in a stepped shape or a tapered shape, the area of the joint surface between the main body resin lining layer and the flange resin lining layer becomes large, and a stronger joint is formed. can do.

[Brief description of drawings]

FIG. 1 is a view showing a first embodiment of a method for manufacturing a resin-lined steel pipe with a flange according to the present invention, which is a cross-sectional view showing a state before inserting a synthetic resin pipe as a main body lining layer into a steel pipe main body. Is.

FIG. 2 is a cross-sectional view showing a state in which a main body lining layer is formed in the steel pipe main body of the first embodiment.

FIG. 3 is a cross-sectional view showing a state in which an injection mold is set on the flange of the first embodiment and resin is injected into the cavity.

FIG. 4 is a cross-sectional view showing a state in which the joint portion between the flange resin lining layer and the main body resin lining layer of the first embodiment is fusion-bonded using a heating plate.

FIG. 5 is a view showing a second embodiment of the method for manufacturing a resin lining steel pipe with a flange according to the present invention, and a sectional view showing a state where an injection mold is set on the flange.

FIG. 6 is a cross-sectional view showing a state in which the joint portion between the flange resin lining layer and the main body resin lining layer of the second embodiment is fused by using a heating plate.

FIG. 7 is a view showing a third embodiment of the method for manufacturing a resin lining steel pipe with a flange according to the present invention, and a sectional view showing a state where an injection mold is set on the flange.

FIG. 8 is a cross-sectional view showing a state in which a joint portion between the flange resin lining layer and the main body resin lining layer of the third embodiment is fused using a hot platen.

FIG. 9 is a cross-sectional view showing a state before injection molding in the previously proposed method for manufacturing a flanged resin-lined steel pipe.

10 is a cross-sectional view showing the state after injection in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Steel pipe with flange 7 Flange resin lining layer 8 Hot platen (heating means) 3b Main body resin lining layer 11 Steel pipe body 12 Flange 14 Steel pipe body end portion near the flange 32 Step portion 33 Tapered portion

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location F16L 23/026 23/024 23/028 58/10 // B29K 105: 22 B29L 23:22

Claims (2)

[Claims] 1. A flanged steel pipe having a steel pipe main body, a flange provided at an end portion of the steel pipe main body, and a main body resin lining layer that covers an inner wall surface of the steel pipe main body up to the vicinity of the pipe end. A method for manufacturing a flanged resin lining steel pipe, comprising the step of forming a flange resin lining layer reaching a main body resin lining layer by injection molding, wherein a joining portion between the flange resin lining layer and the main body resin lining layer is heated. A method for manufacturing a resin lining steel pipe with a flange, comprising the step of heating to a resin melting temperature according to. 2. The method for producing a resin lining steel pipe with a flange according to claim 1, wherein the inner peripheral edge of the end portion of the main body resin lining layer is cut out in a step shape or a taper shape.