TWI815756B - Anti-corrosion multilayers pipe - Google Patents

Abstract

An anti-corrosion multilayers pipe is provided. The anti-corrosion multilayers pipe comprises a body, a coupling, a clamping ring, and a cladding layer. Through the design of the body, the coupling, and the clamping ring, the anti-corrosion multilayers pipe of the can strengthen the locking ability among them. Moreover, the sealing effect can be improved, and the continuous assembly can be carried out by using the screwing operation between the body, the coupling, and the clamping ring when hanging vertically.

Description

Corrosion-resistant composite pipes

The present invention relates to a steel pipe, in particular to a corrosion-resistant composite pipe.

In existing engineering construction, such as concrete pump trucks, petroleum, chemical industry, shale gas transportation, and material transportation in electric power, metallurgy, coal, mining, cement and other industries, it is widely needed to use excellent wear resistance and heat resistance. Impact performance, corrosion-resistant steel pipe. Especially in oil mining, the presence of highly corrosive media such as carbon dioxide, hydrogen sulfide, chloride ions, and mineralized formation water seriously affects the service life of oil pipelines and the safe operation of oil and gas fields.

At present, it is difficult to achieve the above requirements for steel pipes made of a single material, and it will greatly increase the cost of the product. If two or more pipe bodies with different mechanical properties can be compositely processed, this problem can be solved well and the cost can be greatly reduced. Specifically, composite processed steel pipes refer to steel pipes lined with various anti-corrosion materials, such as plastic, rubber or fiberglass, which have been widely used in pipe bodies for transporting various corrosive media. However, the current composite processed steel pipes are still unable to be used in vertical hanging projects in the harsh operating environment of high temperature and strong acid corrosion.

Therefore, in order to overcome the shortcomings and deficiencies in the prior art, it is necessary for the present invention to provide an improved corrosion-resistant composite pipe to solve the problems existing in the above conventional technology.

The main purpose of the present invention is to provide a corrosion-resistant composite pipe that can be used in vertical hanging projects under the harsh operating environment of high temperature and strong acid corrosion by utilizing the design of the steel pipe body, joints and clamping rings.

In order to achieve the above purpose, the present invention provides a corrosion-resistant composite pipe. The corrosion-resistant composite pipe includes a steel pipe body, a joint, a clamping ring and an outer coating. The steel pipe body includes a pipe fitting, a first external thread section, a second external thread section and a flat section, wherein the first external thread section, the second external thread section and the flat section are formed on an outer surface of the pipe fitting, and the flat section is located on the first external thread between the section and the second external thread section; the joint includes a first internal thread part, a second internal thread part and an internal convex ring part, wherein the first internal thread part, the second internal thread part and the The inner convex ring part is formed on an inner ring surface of the joint, and the inner convex ring part is formed between the first internal thread part and the second internal thread part, and the first internal thread part is configured to be threaded in the On the first externally threaded section of the steel pipe body; the clamping ring includes a fitting portion and an internal threaded portion, wherein the fitting portion and the internal threaded portion are formed on an inner annular surface of the clamping ring, and the sleeve The coupling portion is fitted on the flat section of the steel pipe body, and the second externally threaded section of the steel pipe body is configured for the internally threaded section and the second internally threaded section of the joint to be threaded together; the outer covering includes a first connection section, a second connecting section and an intermediate section, wherein the intermediate section is located between the first connecting section and the second connecting section, and the intermediate section covers the plane section of the steel pipe body, and the first connecting section and The joint is connected, and the second connecting section is connected with the clamping ring.

In one embodiment of the present invention, the first external thread section of the steel pipe body has a first taper full tooth area and a first taper non-taper full tooth area, and the first taper full tooth area is located away from the On one side of the plane section, the first tapered non-taper full tooth area is located on the side close to the plane section.

In one embodiment of the present invention, the second external thread section of the steel pipe body has a second taper full tooth area, a second taper non-taper full tooth area, and a non-taper non-taper full tooth area in sequence. area and an annular slot area, the second tapered full tooth area is located on a side away from the plane section, and the annular slot area is located on a side close to the plane section.

In one embodiment of the present invention, the steel pipe body further includes a lining pipe, two metal rings and two fillet welds. The lining pipe is arranged on an inner annular surface of the pipe fitting, and the metal rings are respectively arranged on On two opposite flat ends of the pipe fitting, corresponding fillet welds are welded between one end of the lining pipe and the adjacent metal ring.

In one embodiment of the present invention, the material of the outer coating includes fiberglass, and the materials of the lining tube and the metal rings include titanium.

In one embodiment of the present invention, the joint further has a first groove and a second groove, the first groove is formed between the first internal thread part and the internal convex ring part, and the second A groove is formed between the second internal thread part and the internal convex ring part.

In one embodiment of the present invention, the joint further has a first annular gasket and a second annular gasket, and the inner convex ring portion has a first positioning end face and a second positioning end face, and the first ring The ring-shaped gasket is disposed on the first positioning end face facing the first internal thread part, and the second annular gasket is disposed on the second positioning end face facing the second internal thread part.

In one embodiment of the present invention, the clamping ring further includes a beveled groove and an annular gasket. The beveled groove is formed on an end surface of the clamping ring, and the beveled groove is adjacent to the Internal thread part.

In one embodiment of the present invention, the clamping ring further includes a positioning annular end surface, and the positioning annular end surface is located between the internal thread part and the fitting part.

In one embodiment of the present invention, an upper bevel end of the first connecting section of the outer covering is attached to the lower bevel end of the joint, and an upper bevel end of the second connecting section of the outer covering is attached to the lower bevel end of the joint. The lower beveled ends of the clamping rings are attached together.

As mentioned above, the corrosion-resistant composite pipe of the present invention can meet the needs of special geological environments by designing a steel pipe body made of carbon steel as the main body, and at the same time, a lining pipe is provided on the inner ring surface of the pipe fitting, where the material of the lining pipe includes Titanium, titanium alloy or stainless steel pipes, the outer surface of the pipe is covered with the outer coating, and the outer coating is glass fiber, thereby obtaining a composite pipe with high temperature resistance, acid corrosion resistance and high structural strength. In addition, the corrosion-resistant composite pipe of the present invention can strengthen the locking ability between each other through the design of the steel pipe body, the joint and the clamping ring, and at the same time improve its sealing effect. The steel pipe body, the steel pipe body, the joint and the clamping ring can be used for vertical hanging. The screwing operation between the joint and the clamping ring allows for continuous assembly. The corrosion-resistant composite pipe of the present invention still has good tolerance performance of non-corrosion and non-deterioration in a high-temperature corrosive environment with a temperature below 150°C and pH=1~2, thereby reducing the cost of the product and further enabling the corrosion-resistant composite pipe to be Pipes are widely used in various material transportation.

In order to make the above and other objects, features, and advantages of the present invention more apparent and understandable, embodiments of the present invention will be described in detail below along with the accompanying drawings. Furthermore, the directional terms mentioned in the present invention include, for example, up, down, top, bottom, front, back, left, right, inside, outside, side, peripheral, central, horizontal, transverse, vertical, longitudinal, axial, Radial, uppermost or lowermost, etc., are only directions with reference to the attached drawings. Therefore, the directional terms used are to illustrate and understand the present invention, but not to limit the present invention.

Please refer to Figures 1 and 2, which are corrosion-resistant composite pipes according to an embodiment of the present invention. The corrosion-resistant composite pipes include a steel pipe body 2, a joint 3, a clamping ring 4 and an outer coating 5. After additional combination, the steel pipe body 2, the joint 3, the clamping ring 4 and the outer coating 5 can become a composite steel pipe with high temperature resistance, acid corrosion resistance and high structural strength. The detailed structure, assembly relationship and operating principle of each component will be described in detail below.

Continuing to refer to Figures 1 and 2, the steel pipe body 2 includes a pipe fitting 21, a first external thread section 22, a second external thread section 23 and a planar section 24, wherein the first external thread section 22, the The second external thread section 23 and the flat section 24 are formed on an outer surface of the pipe 21 , and the flat section 24 is located between the first external thread section 22 and the second external thread section 24 .

Please refer to Figures 2 and 3. Further, the first external thread section 22 of the steel pipe body 2 has a first taper full tooth area 221 (Perfect Threads) and a first taper non-taper full tooth area. 222 (Imperfect Threads), the first tapered full tooth area 221 is located on the side away from the planar section 24 , and the first tapered non-tapered full tooth area 222 is located on the side close to the planar section 24 . Through the design of the first taper full tooth area 221 and the first taper non-taper full tooth area 222, the first external thread section 22 of the steel pipe body 2 can be firmly locked with the joint 3.

In addition, the second external thread section 23 of the steel pipe body 2 has a second taper full tooth area 231, a second taper non-taper full tooth area 232, a non-taper non-taper full tooth area 233 and An annular slotted hole area 234, in which the second tapered full tooth area 231 is on the side away from the planar section 24, the annular slotted hole area 234 is located on the side close to the planar section 24, and the annular slotted hole area 234 Configured to position the clamping ring 4 . In this embodiment, the length of the second taper full tooth area 231 is the same as the length of the second taper non-taper full tooth area 232, and the length of the second taper non-taper full tooth area 232 is the same as the length of the non-taper tooth area 231. The length of the tapered non-tapered full tooth area 233 is the same, and the length of the annular slot area 234 is smaller than the length of the non-tapered non-tapered full tooth area 233 . Through the design of the second taper full tooth area 231 and the second taper non-taper full tooth area 232, the second external thread section 23 of the steel pipe body 2 can be firmly locked with the clamping ring 4 , at the same time, by utilizing the design of the non-taper non-taper full-tooth area 233 and the annular slot area 234, the clamping ring 4 can be gradually moved in the direction of the plane section 24 and limited in the annular groove. Hole area 234.

Please refer to Figures 1, 5 and 6. The steel pipe body 2 also includes a lining pipe 25, two metal rings 26 and two fillet welds 27. The lining pipe 25 is arranged on an inner ring of the pipe fitting 21. surface, and the metal rings 26 are respectively arranged on two opposite planar ends of the pipe member 21, and corresponding fillet welds 27 are welded between one end of the lining pipe 25 and the adjacent metal rings 26. In this embodiment, the fillet weld 27 is connected between the corresponding lining pipe 25 and the metal ring 26 to form a plane (see Figure 6). In addition, the material of the outer coating 5 includes glass fiber, and the materials of the lining tube 25 and the metal rings 26 include titanium, titanium alloy or stainless steel. Since the outer coating 5 , the inner lining pipe 25 and the metal rings 26 have high wear resistance, high thermal shock resistance and corrosion resistance, through the outer coating 5 , the inner lining pipe 25 and the metal rings The design of the ring 26 enables both the outer surface and the inner ring surface of the pipe 21 to be covered, thereby obtaining a composite pipe that is resistant to high temperatures, acid corrosion, and has high structural strength.

Please refer to Figures 1, 2 and 7, the joint 3 includes a first internal thread part 31, a second internal thread part 32 and an internal convex ring part 33, wherein the first internal thread part 31, the The second internal thread part 32 and the inner convex ring part 33 are formed on an inner ring surface of the joint 3 , and the inner convex ring part 33 is formed between the first internal thread part 31 and the second internal thread part 32 , the first internal thread portion 31 is configured to be threaded on the first external thread section 22 of the steel pipe body 2, and the second internal thread portion 32 is configured to be screwed on the steel pipe body 2 of another corrosion-resistant composite pipe. The second external thread section 23. In this embodiment, the material of the joint 3 includes titanium, titanium alloy or stainless steel.

Continuing to refer to Figures 1, 2 and 7, furthermore, the connector 3 also has a first groove 34 and a second groove 35. The first groove 34 and the second groove 35 are It is recessed from the inner ring surface of the joint 3 and is located on two opposite sides of the inner convex ring portion 33 , wherein the first groove 34 is formed between the first internal thread portion 31 and the inner convex ring portion 33 . Two grooves 35 are formed between the second internal thread part 32 and the internal convex ring part 33 . When the joint 3 is combined with the steel pipe body 2, the design of the first groove 34 and the second groove 35 can provide a buffer space and disperse the accumulated energy during the threading of the joint 3 and the steel pipe body 2. stress, and at the same time, the first internal thread portion 31 and the first external thread section 22 can be prevented from being locked too tightly or too loosely.

In addition, the joint 3 also has a first annular gasket 36 and a second annular gasket 37. The inner convex ring portion 33 has a first positioning end surface 331 and a second positioning end surface 332. The first positioning end surface 331 and the second positioning end surface 332 are located on two opposite sides of the inner convex ring part 33. The first annular gasket 36 is disposed on the first positioning end surface 331 facing the first internal thread part 31. The second The annular gasket 37 is disposed on the second positioning end surface 332 facing the second internal thread portion 32 . In this embodiment, the material of the first annular gasket 36 and the second annular gasket 37 includes Teflon or expanded polytetrafluoroethylene (ePTFTE). When the joint 3 is combined with the steel pipe body 2, through the design of the first annular gasket 36 and the second annular gasket 37, the stress generated when the joint 3 and the steel pipe body 2 are screwed together can be absorbed. .

Please refer to Figure 1, Figure 2 and Figure 8. The clamping ring 4 is configured for clamping by a machine tool (not shown). The clamping ring 4 includes a fitting portion 41 and an internal thread portion 42. , wherein the fitting portion 41 and the internal threaded portion 42 are formed on an inner ring surface of the clamping ring 4, and the fitting portion 41 is fitted on the plane section 24 of the steel pipe body 2, and the steel pipe body 2 The second external thread section 23 is configured to be threaded with the internal thread portion 42 of the clamping ring 4 and the second internal thread portion 32 of the joint 3 . In this embodiment, the material of the clamping ring 4 includes titanium, titanium alloy or stainless steel.

Please refer to Figures 1, 9 and 10. Further, the clamping ring 4 further includes a bevel groove 43 and an annular gasket 44. The bevel groove 43 is formed on the clamping ring 4. On one end surface of the groove 43 , the bevel groove 43 is adjacent to the internal thread portion 42 . In this embodiment, the material of the annular gasket 44 includes Teflon or expanded polytetrafluoroethylene (ePTFTE). When the second externally threaded section 23 of the steel pipe body 2 is screwed together with the clamping ring 4 and another joint 3 in sequence, through the design of the bevel groove 43 and the annular gasket 44, the clamping ring can be provided 4 and the buffering when the joint 3 contacts.

In addition, the clamping ring 4 further includes a positioning annular end face 45 , the positioning annular end face 45 is located between the internal thread portion 42 and the fitting portion 41 , and the positioning annular end face 45 is configured to position the clamping ring 4 At a specific position of the second external thread section 23 of the steel pipe body 2.

Please refer to FIGS. 1 and 2 , the outer covering 5 includes a first connecting section 51 , a second connecting section 52 and an intermediate section 53 , wherein the intermediate section 53 is located between the first connecting section 51 and the third connecting section 51 . between the two connecting sections 52, and the middle section 53 covers the plane section 24 of the steel pipe body 2. In this embodiment, the first connecting section 51 is connected to the joint 3, and the second connecting section 52 is connected to the joint 3. The clamping rings 4 are connected.

Continuing to refer to Figures 1 and 2, furthermore, an upper bevel end 511 of the first connecting section 51 of the outer covering 5 is attached to the lower bevel end 38 of the joint 3. The outer covering 5 An upper bevel end 521 of the second connecting section 52 is attached to the lower bevel end 46 of the clamping ring 4 . Through the design of the upper slope end 511 of the first connecting section 51 and the upper slope end 521 of the second connecting section 52, the outer coating 5 can continuously cover the joint 3, the steel pipe body 2 and the clamping ring 4, thus improving its sealing effect and strengthening the covering property of the outer coating 5.

According to the above structure, the joint 3 and the clamping ring 4 are combined on the steel pipe body 2, and the outer coating 5 is continuously covered on the joint 3, the steel pipe body 2 and the clamping ring 4. , so that the outer surface of the steel pipe body 2 is coated to improve its sealing effect. At the same time, the outer coating 5 has high wear resistance, high thermal shock resistance and corrosion resistance, and is expected to be able to withstand severe corrosion at high temperatures and strong acids. In the working environment, it is used in vertical hanging projects to lock the threads of continuous pipes. It is estimated that the maximum withstand temperature is 150 ℃, and it can resist strong acid corrosion with pH=1~2.

As mentioned above, the corrosion-resistant composite pipe of the present invention can meet the needs of special geological environments by designing a steel pipe body 2 made of carbon steel as the main body, and at the same time, the lining pipe 25 is provided on the inner ring surface of the pipe fitting 21, wherein the lining pipe The material of 25 includes titanium, titanium alloy or stainless steel pipe. The outer surface of the pipe 21 is covered with the outer coating 5. The outer coating 5 is glass fiber, thereby obtaining a composite pipe with high temperature resistance, acid corrosion resistance and high structural strength. . In addition, the corrosion-resistant composite pipe of the present invention can strengthen the locking ability between each other through the design of the steel pipe body 2, the joint 3 and the clamping ring 4, and at the same time improve its sealing effect, which can be used when hanging vertically. The steel pipe body 2, the joint 3 and the clamping ring 4 are screwed together for continuous assembly. The corrosion-resistant composite pipe of the present invention still has good tolerance performance of non-corrosion and non-deterioration in a high-temperature corrosive environment with a temperature below 150°C and pH=1~2, thereby reducing the cost of the product and further enabling the corrosion-resistant composite pipe to be Pipes are widely used in various material transportation.

Please refer to Figure 11 , which is a corrosion-resistant composite pipe according to another embodiment of the present invention. It is similar to the above-mentioned embodiment of the present invention and generally uses the same component names and drawing numbers. The corrosion-resistant composite pipe includes a steel pipe body 2, A joint 3, a clamping ring 4 and an outer coating 5. The difference of the embodiment of the present invention is that the material of the joint 3 includes carbon steel, and the joint 3 also has a first collar 391 and two collars. Gasket 392 , wherein the materials of the first collar 391 and the collar gaskets 392 include titanium, titanium alloy or stainless steel, and the first collar 391 is wrapped in an inner part of the inner convex ring part 33 The annular surface, and the opposite sides of the first collar 391 each form a bevel hole 390, and the bevel holes 390 are configured for the collar gaskets 392 to fit therein respectively. As shown in FIG. 12 , the thickness of the end edge of the pipe 21 close to the first external thread section 22 matches the thickness of the first collar 391 , and the hypotenuse hole 390 adjacent to the first internal thread portion 31 is configured to A collar gasket 392 is fitted therein. When the first external thread section 22 is locked on the first internal thread portion 31 , the collar gasket 392 adjacent to the first internal thread portion 31 is configured to absorb the The extrusion force of the pipe 21. In addition, the bevel hole 390 adjacent to the second internal thread portion 32 is configured for another collar gasket 392 to fit therein when the second external thread section 23 is locked in the second internal thread portion 32 , the collar gasket 392 adjacent to the second internal thread portion 32 is configured to absorb the extrusion force of the pipe 21 .

Please refer to Figure 13, which is a corrosion-resistant composite pipe according to another embodiment of the present invention. It is similar to the above-mentioned embodiment of the present invention and generally uses the same component names and drawing numbers. The corrosion-resistant composite pipe includes a steel pipe body 2, A joint 3, a clamping ring 4 and an outer coating 5. The difference of the embodiment of the present invention is that the material of the joint 3 includes carbon steel, and the joint 3 also has a second collar 393, in which the pipe fitting 21 The thickness of the end edge near the first external thread section 22 matches the thickness of the second collar 393. The material of the second collar 393 includes Teflon or expanded polytetrafluoroethylene, and the second collar 393 is made of Teflon or expanded polytetrafluoroethylene. The collar 392 covers an inner annular surface of the inner convex ring portion 33. The design of the second collar 393 can replace the need to manufacture the joint 3 to prevent corrosion, effectively reducing the manufacturing cost.

Although the present invention has been disclosed through embodiments, they are not intended to limit the present invention. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection of the present invention is The scope shall be determined by the appended patent application scope.

2:Steel pipe body 21:Pipe fittings 22: First external thread section 221: First taper full tooth area 222: First taper non-taper full tooth area 23: Second external thread section 231: Second taper full tooth area 232: Second taper non-taper full tooth area 233: No taper, taper, non-taper, full tooth area 234: Annular slot area 24: Plane segment 25: Lined pipe 26:Metal ring 27: Fillet welding 3: Connector 31: First internal thread part 32: Second internal thread part 33: Inner convex ring part 331: First positioning end face 332: Second positioning end face 34: First trench 35:Second trench 36: First ring gasket 37:Second ring gasket 38: Lower bevel end 390: hypotenuse hole 391:The first set of rings 392: Collar gasket 393:Second set of rings 4: Clamping ring 41: Fitting Department 42: Internal thread part 43: hypotenuse groove 44: Ring gasket 45: Positioning the annular end face 46: Lower bevel end 5: Outer covering 51: First connection section 511: Upper bevel end 52: Second connection section 521: Upper bevel end 53: middle section

Figure 1 is a schematic diagram of a corrosion-resistant composite pipe assembled according to an embodiment of the present invention. Figure 2 is an exploded schematic diagram of a corrosion-resistant composite pipe component according to an embodiment of the present invention. Figure 3 is a partial schematic view of the first external thread section of a corrosion-resistant composite pipe according to an embodiment of the present invention. Figure 4 is a partial schematic diagram of a second externally threaded section of a corrosion-resistant composite pipe according to an embodiment of the present invention. Figure 5 is a schematic diagram of a steel pipe body of a corrosion-resistant composite pipe according to an embodiment of the present invention. FIG. 6 is a partial enlarged view of area A in FIG. 5 . Figure 7 is a schematic diagram of a joint of a corrosion-resistant composite pipe according to an embodiment of the present invention. Figure 8 is a schematic diagram of a clamping ring of a corrosion-resistant composite pipe according to an embodiment of the present invention. Figure 9 is a partial schematic diagram showing the positioning annular end surface of a corrosion-resistant composite pipe according to an embodiment of the present invention. Figure 10 is a partial schematic diagram showing a bevel groove and annular gasket of a corrosion-resistant composite pipe according to an embodiment of the present invention. Figure 11 is a schematic diagram of another embodiment of a corrosion-resistant composite pipe assembled together according to an embodiment of the present invention. FIG. 12 is a partial enlarged view of FIG. 11 . Figure 13 is a schematic diagram of yet another embodiment of a corrosion-resistant composite pipe assembled together according to an embodiment of the present invention.

2:Steel pipe body

21:Pipe fittings

22: First external thread section

23: Second external thread section

24: Plane segment

25: Lined pipe

26:Metal ring

3: Connector

31: First internal thread part

32: Second internal thread part

33: Inner convex ring part

34: First trench

35:Second trench

36: First ring gasket

37:Second ring gasket

38: Lower bevel end

4: Clamping ring

41: Fitting Department

42: Internal thread part

43: hypotenuse groove

44: Ring gasket

45: Positioning the annular end face

46: Lower bevel end

5: Outer covering

51: First connection section

52: Second connection section

53: middle section

Claims (12)

A corrosion-resistant composite pipe, including: A steel pipe body includes a pipe fitting, a first external thread section, a second external thread section and a flat section, wherein the first external thread section, the second external thread section and the flat section are formed on a side of the pipe fitting. The outer surface, and the plane section is located between the first external thread section and the second external thread section; A joint includes a first internal thread part, a second internal thread part and an inner convex ring part, wherein the first internal thread part, the second internal thread part and the inner convex ring part are formed on a part of the joint An inner ring surface, and the inner convex ring portion is formed between the first internal thread portion and the second internal thread portion, and the first internal thread portion is configured to be threaded on the first external thread section of the steel pipe body; A clamping ring includes a fitting portion and an internal threaded portion, wherein the fitting portion and the internal threaded portion are formed on an inner annular surface of the clamping ring, and the fitting portion is fitted on the steel pipe body. On the plane section, the second externally threaded section of the steel pipe body is configured for threading between the internally threaded part and the second internally threaded part of the joint; and An outer coating includes a first connecting section, a second connecting section and an intermediate section, wherein the intermediate section is located between the first connecting section and the second connecting section, and the intermediate section covers the steel pipe body The planar section is connected to the first connecting section and the joint, and the second connecting section is connected to the clamping ring. The corrosion-resistant composite pipe as claimed in claim 1, wherein the first external thread section of the steel pipe body has a first tapered full tooth area and a first tapered non-taper full tooth area, and the first tapered full tooth area The first tapered non-tapered full tooth area is located on the side close to the planar section. The corrosion-resistant composite pipe as described in claim 1, wherein the second external thread section of the steel pipe body has a second taper full tooth area, a second taper non-taper full tooth area, and a non-taper non-taper tooth area in sequence. A tapered full tooth area and an annular slot area, the second tapered full tooth area is located on a side away from the plane section, the annular slot area is located on a side close to the plane section, and the annular slot area is configured To position the clamping ring. The corrosion-resistant composite pipe as claimed in claim 1, wherein the steel pipe body further includes a lining pipe, two metal rings and two fillet welds, the lining pipe is arranged on an inner ring surface of the pipe fitting, and the metal rings Rings are respectively arranged on two opposite planar ends of the pipe fitting, and corresponding fillet welds are welded between one end of the lining pipe and the adjacent metal ring. The corrosion-resistant composite pipe as claimed in claim 4, wherein the material of the outer coating includes fiberglass, and the materials of the lining pipe and the metal rings include titanium, titanium alloy or stainless steel. The corrosion-resistant composite pipe as claimed in claim 1, wherein the joint further has a first groove and a second groove, and the first groove is formed between the first internal thread part and the internal convex ring part. , the second groove is formed between the second internal thread part and the internal convex ring part. The corrosion-resistant composite pipe as claimed in claim 1, wherein the joint further has a first annular gasket and a second annular gasket, and the inner convex ring portion has a first positioning end face and a second positioning end face, The first annular gasket is disposed on the first positioning end face facing the first internal thread part, and the second annular gasket is disposed on the second positioning end face facing the second internal thread part. The corrosion-resistant composite pipe as claimed in claim 1, wherein the clamping ring further includes a bevel groove and an annular gasket, the bevel groove is formed on one end surface of the clamping ring, and the bevel The groove is adjacent to the internally threaded portion. The corrosion-resistant composite pipe as claimed in claim 1, wherein the clamping ring further includes a positioning annular end surface, the positioning annular end surface is located between the internal thread part and the fitting part. The corrosion-resistant composite pipe as claimed in claim 1, wherein an upper bevel end of the first connection section of the outer coating is attached to the lower bevel end of the joint, and an upper bevel end of the second connection section of the outer coating is attached together. The upper bevel end is attached to the lower bevel end of the clamping ring. The corrosion-resistant composite pipe as claimed in claim 1, wherein the joint further has a first collar and two collar gaskets, the first collar covers an inner annular surface of the inner convex ring portion, and the Two opposite sides of the first collar each form a bevel hole, and the bevel holes are configured for the collar gaskets to be fitted therein respectively. The corrosion-resistant composite pipe as claimed in claim 1, wherein the joint further has a second collar, and the second collar covers an inner ring surface of the inner convex ring portion.