KR20180110573A - Clad pipe producting apparatus using water pressure expansion and clad pipe producting method - Google Patents

Abstract

The present invention relates to a clad steel pipe manufacturing apparatus, and more particularly, to an apparatus for manufacturing a clad steel pipe, comprising: an outer pipe jig that supports the outer pipe; And an inner gutter configured to support an inner tube having an outer diameter smaller than the inner diameter of the outer tube by a predetermined gap and to supply and discharge water into the inner tube, Wherein the inner tube is formed of an inner alloy steel, the inner tube being inserted into the inner tube and fixing the position of the inner tube; An inner pipe hermetic seal coupled to one end of the inner pipe to seal the one end; A water supply pipe coupled to the inner frame and supplying water to the other open end of the inner pipe; And a water discharge pipe provided at one side of the water supply pipe for discharging the water inside the inner pipe to the outside, the outer pipe being moved so as to receive the inner pipe inside the outer pipe, The inner tube is plastically deformed by the predetermined gap, and the outer wall surface of the inner tube is tightly coupled to the inner wall surface of the outer tube so that the clad steel tube is manufactured .

Description

Technical Field [0001] The present invention relates to a clad steel pipe manufacturing apparatus and a clad pipe manufacturing method using the same,

The present invention relates to a clad steel pipe manufacturing apparatus and a clad steel pipe manufacturing method using the clad steel pipe manufacturing apparatus. More particularly, the present invention relates to a hydraulic inflatable clad steel pipe manufacturing apparatus capable of manufacturing a clad steel pipe having various diameters by water pressure, To a method of manufacturing a steel pipe.

Clad pipes are used for mining / refining and transporting corrosive oil or gas. The inner wall of the clad pipe directly contacting the oil or gas is formed of Corrosion Resistant Alloy (CRA), and the outer wall is formed of a general steel. That is, a clad steel pipe is a steel pipe formed by joining two different materials.

The reason why the clad steel pipe is formed of two different materials is that the corrosion-resistant alloy steel is expensive. That is, only the inner wall where the oil or gas is directly contacted is made of an inner alloy steel, and the stress is received by the ordinary steel of the outer wall.

Conventionally, a clad steel pipe manufacturing method can be divided into a metallurgical bonding method and a mechanical bonding method according to a clad bonding technique.

The steel pipe of the metal joining method is manufactured by joining the inner wall of the alloy steel through the known overlay welding or rolling or press fitting the already processed clad plate and performing seam welding.

In the mechanical coupling method, two tubes of two different materials (inner tube made of inner alloy steel and outer tube made of steel) are pressed together in a press or hydraulic molding die to join the two tubes together.

However, when a clad steel pipe is manufactured by a metal bonding method, it has an excellent bonding property and can be applied to a large-diameter steel pipe having a diameter of 24 inches or more. However, it has a disadvantage of high price and low productivity. In addition, it is not applicable to large-diameter steel pipes and has a disadvantage that it can not be applied to seamless pipes.

On the other hand, when a clad steel pipe is manufactured by a mechanical bonding method, it is advantageous in that it is highly productive and can be applied to a sealmless pipe with a low price. However, there is a disadvantage that the bonding property is inferior to the metal bonding method.

1 is a perspective view and a sectional view showing a state where two clad steel pipes 10 and 10a manufactured by a conventional clad pipe manufacturing method are connected to each other.

Since the clad steel pipe is extended several kilometers in length for gas transportation at the work site, a plurality of clad steel pipes are welded to each other. As shown in FIG. 1 (a), the two adjacent clad steel pipes 10 and 10a are arranged so that their end portions are in contact with each other, and joint welding 20 is performed.

As shown in Fig. 1 (b), each of the clad steel pipes 10 and 10a has the same thickness of the outer walls 10 and 10a, but the thickness d1? Of the inner wall 11.11a formed of the inner- d2) become non-uniform.

As a result, a difference (h) occurs in the thicknesses of the connection portions of the two pipes. If joint welding 20 is performed in this state, welding failure occurs. In order to prevent such welding failure, the thickness of the inner wall of the thicker side may be adjusted to be equal to the thickness of both sides. However, in this case, the overlay welding area is cut off, An additional problem has occurred.

Registered Patent No. 10-1579080 entitled " Cladded Steel Pipe Manufacturing Method for Bonding Steel Pipes of Different Material by Thermal Fusion Method "

SUMMARY OF THE INVENTION It is an object of the present invention to provide a new type of clad steel pipe manufacturing apparatus capable of improving productivity of a clad steel pipe with high productivity and a method of manufacturing a clad steel pipe using the same.

Another object of the present invention is to provide a method of manufacturing a clad steel pipe capable of eliminating a welding defect in a connecting region when a plurality of clad steel pipes are connected to each other.

The above objects and various advantages of the present invention will become more apparent from the preferred embodiments of the present invention by those skilled in the art.

The object of the present invention can be achieved by a hydraulic inflatable clad pipe manufacturing apparatus. The clad steel pipe manufacturing apparatus of the present invention comprises: an outer pipe jig which supports the outer pipe and is movable; And an inner gutter configured to support an inner tube having an outer diameter smaller than the inner diameter of the outer tube by a predetermined gap and to supply and discharge water into the inner tube, Wherein the inner tube is formed of an inner alloy steel, the inner tube being inserted into the inner tube and fixing the position of the inner tube; An inner pipe hermetic seal coupled to one end of the inner pipe to seal the one end; A water supply pipe coupled to the inner frame and supplying water to the other open end of the inner pipe; And a water discharge pipe provided at one side of the water supply pipe for discharging the water inside the inner pipe to the outside, the outer pipe being moved so as to receive the inner pipe inside the outer pipe, The inner tube is plastically deformed by the predetermined gap, and the outer wall surface of the inner tube is tightly coupled to the inner wall surface of the outer tube so that the clad steel tube is manufactured .

According to an embodiment of the present invention, it is possible to further include a welded portion that welds and fixes both ends of the inner tube and the outer tube which are in close contact with each other by water pressure.

On the other hand, the object of the present invention can be achieved by a method for manufacturing a hydraulic inflatable clad pipe. The method for manufacturing a clad steel pipe of the present invention includes the steps of forming an inner pipe by welding a boundary region of the inner alloy plate not in a cylindrical shape; Moving an outer tube having a diameter larger by a predetermined gap than the inner tube to cover the outside of the inner tube; Closing one end of the inner tube; Continuously supplying water, which forms a water pressure higher than the yield strength of the inner tube, inside the inner tube; Discharging the water inside the inner tube to the outside when the inner tube wall of the outer tube and the outer wall surface of the inner tube are in close contact with each other by plastic deformation when the inner tube is extended by the set gap by the water pressure; And welding both ends of the inner tube to the outer tube to complete the manufacture of the clad steel pipe.

According to one embodiment, when both ends of the inner tube are welded to the outer tube, the thickness of the thickness adjusting welding band formed inside the inner tube, the thickness of the inner tube and the thickness of the outer tube plus the total thickness And adjusting the thickness of the thickness-adjusting welding band so that the sum of the thickness of the thickness adjusting welding band is equal at both ends of the clad steel pipe.

The clad steel pipe manufacturing apparatus and the clad steel pipe manufacturing method according to the present invention are characterized in that an inner pipe formed to have a smaller set gap than the outer pipe is disposed concentrically inside the outer pipe and a water pressure greater than the breakage pressure is formed inside the inner pipe Water is supplied to expand the inner tube by water pressure, to adhere to the inner wall surface of the outer tube, and to weld the both ends to produce a clad steel pipe.

Since the clad steel pipe according to the present invention is manufactured by applying a uniform water pressure inside the inner pipe, the bonding property between the inner pipe and the outer pipe is improved. In addition, since the inner pipe is manufactured by plastic deformation by water pressure, the productivity can be increased as compared with the conventional metal bonding method, and it is also applicable to the seamless steel pipe compared to the mechanical bonding method.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view showing a structure of a connecting portion of a plurality of conventional clad steel pipes,
2 is a schematic view schematically showing the construction of a clad steel pipe manufacturing apparatus according to the present invention,
FIG. 3 is an exemplary view showing the state of the outer tube and the inner tube in the state of FIG. 2,
FIGS. 4 to 6 are schematic views illustrating a process of manufacturing a clad steel pipe using the clad steel pipe manufacturing apparatus according to the present invention.
7 is a view showing an example of a clad steel pipe manufactured using the clad steel pipe manufacturing apparatus according to the present invention,
8 is a view illustrating a shape of a connection portion of a plurality of clad steel pipes manufactured by using the clad pipe manufacturing apparatus according to the present invention,
FIG. 9 and FIG. 10 are views showing the result of structural analysis of the bonding pressure of the clad steel pipe manufactured by the clad pipe manufacturing apparatus according to the present invention.

For a better understanding of the present invention, a preferred embodiment of the present invention will be described with reference to the accompanying drawings. The embodiments of the present invention may be modified into various forms, and the scope of the present invention should not be construed as being limited to the embodiments described in detail below. The present embodiments are provided to enable those skilled in the art to more fully understand the present invention. Therefore, the shapes and the like of the elements in the drawings can be exaggeratedly expressed to emphasize a clearer description. It should be noted that in the drawings, the same members are denoted by the same reference numerals. Detailed descriptions of well-known functions and constructions which may be unnecessarily obscured by the gist of the present invention are omitted.

2 is a schematic view schematically showing the construction of a clad steel pipe manufacturing apparatus 100 according to the present invention.

As shown in the figure, the clad steel pipe manufacturing apparatus 100 according to the present invention is manufactured by joining an outer pipe 110 made of steel and an inner pipe 120 made of an inner alloy steel to each other. In this case, since the clad steel pipe manufacturing apparatus 100 according to the present invention is manufactured by expanding the inner pipe 120 by water pressure and bringing it into close contact with the inner wall face of the outer pipe 110, the adhesiveness of the entire region can be uniformly improved And it is advantageous in that productivity can be improved by a simple manufacturing method.

The outer tube 110 according to a preferred embodiment of the present invention is made of steel and the inner tube 120 is made of Inconel 625 of the corrosion-resistant alloy steel, but this is merely an example, and various types of inner alloy steel can be used.

The apparatus 100 for manufacturing a clad steel pipe according to the present invention includes an outer tube jig 130 for supporting an outer tube 110, an inner tube fixing part 140 for supporting the inner tube 120, And welds 150 that form welded and thickness-controlled weld bands 160.

The outer tube jig 130 fixes the position of the outer tube 110 during the process of joining the outer tube 110 and the inner tube 120 to each other. The outer tube jig 130 fixes the outer surface of the outer tube 110 so that the inner tube 120 can be inserted into the outer tube 110. The outer tube jig 130 may be formed with an insertion hole corresponding to the outer diameter of the outer tube 110 so that the outer tube 110 is inserted therein. In addition, the outer tube 110 may be provided in various forms capable of supporting the outer tube 110.

The outer pipe jig 130 is provided with a moving wheel at a lower portion thereof.

The inner pipe 140 supports the inner pipe 120 to connect the outer pipe 110 and the inner pipe 120 and supplies the water W to the inner pipe 120.

The inner pipe 140 is inserted into the inner pipe 120 to fix the inner pipe 120 and the inner pipe 141 is connected to the inner pipe 141 to supply the water W to the inner pipe 120 A water discharge pipe 145 connected to the inner frame 141 and discharging the water W in the inner pipe 120 to the outside and a water discharge pipe 145 connected to the inner frame 141 to seal one end of the inner pipe 120 And an inner tube hermetic support 147.

The inner frame 141 is disposed inside the inner tube 120 in the longitudinal direction of the inner tube 120 with a radial cross section to fix the shape of the inner tube 120. The inner frame 141 is designed so as not to interfere as much as possible with the water supplied into the inner tube 120 from contacting the inner wall surface of the inner tube 120.

The water supply pipe 143 extends from the inner frame 141 and supplies the water W to the inner pipe 120. The water supply pipe 143 is connected to the water supply pump to supply water. The water discharge pipe 145 is provided at one side of the water supply pipe 143 to discharge the water inside the internal pipe 120 to the outside. The water discharge pipe 145 is provided with an opening / closing valve. When the water supply pump is driven and water is supplied to the internal pipe 120 through the water supply pipe 143, the on / off valve is closed, the driving of the water supply pump is stopped, and when the internal pipe 120 is plastic- The valve is opened to discharge the water in the inner pipe 120 to the outside.

The inner tube hermetic support part 147 is coupled to one end of the inner tube 120 to open one end of the inner tube 120. As shown in FIG. 2, one end of the inner tube 120 is closed by the inner tube closed support portion 147 and the other end is opened. A water supply pipe 143 and a water discharge pipe 145 are provided at the other end of the opened inner pipe 120.

Here, although not shown in the drawing, the internal gauge fixing unit 140 is provided with a pressure gauge, and the pressure applied to the internal pipe 120 by the water supplied to the inside is indicated. The yield pressure of the inner tube 120 according to the material and thickness of the inner tube 120 is obtained by experiment and data is obtained. The water supply pump continuously supplies water to the inner pipe 120 so that a water pressure higher than the yield pressure corresponding to the type of the inner pipe 120 coupled to the inner pipe 140 is applied.

The weld 150 welds the inner tube 120 coupled to the inner tube 140 in a fused state to complete the molding of the inner tube 120. The weld 150 welds the joint along the longitudinal direction of the inner tube 120.

At this time, the welding part 150 may be a plasma arc welding (PAW) method or a gas tungsten arc welding (GTAW) method.

The welded bead 121 is formed in the inner pipe 120, as shown in FIG.

6, when the inner tube 120 is inflated by the water pressure and is in close contact with the inner wall surface of the outer tube 110, both ends of the inner tube 120 are connected to the outer tube 110, So that the positions of the inner tube 120 and the outer tube 110 are fixed.

A clad steel pipe manufacturing method using the clad steel pipe manufacturing apparatus 100 according to the present invention having such a construction will be described.

As shown in FIG. 2, the outer tube 110 made of steel is coupled to the outer tube jig 130 and fixed in position. The inner tube 120 is inserted into the inner frame 141 in a state in which the plate-like inner type alloy steel does not come round and is in contact with the outer tube.

As shown in FIG. 3, the welding part 151 welded to the welded part 150 welds the welding part to weld the bead 121 to complete the forming of the inner tube 120. At one end of the inner tube 120, an inner tube sealing support 147 is coupled to seal the inner tube 120.

At this time, as shown in FIG. 3, the outer tube 110 has an outer diameter R1 and a thickness t1. The inner tube 120 has an outer diameter R2 smaller than the inner diameter of the outer tube 110, and a thickness t2. The outer diameter of the inner tube 120 is smaller than the inner diameter of the outer tube 110 by a predetermined gap G. The setting gap G is set to a range in which the internal tube 120 can be plastically deformed by water pressure.

The outer tube jig 130 is moved to the inner tube holder 140 and the inner tube 120 is inserted into the outer tube 110 as shown in FIG. The outer tube 110 and the inner tube 120 are disposed concentrically and superimposed on each other.

In this state, the water supply pump is driven to supply the water to the inner pipe 120 through the water supply pipe 143. [ The water supply pump supplies water until the water pressure acting on the inner wall surface of the inner pipe 120 exceeds the inner pipe 120 yield pressure and plastic deformation occurs.

9, the outer tube 110 is made of steel and has an outer diameter R1 of 254 mm and a thickness t1 of 12.7 mm. The inner tube 120 is made of Inconel 625 and has an outer diameter R2 ) Is 222.6 mm, the thickness t2 is 3 mm, the gap G is 3 mm, and the total length is 6000 mm.

The yield strength of inner tube 120 is 507.3 MPa and the corresponding yield pressure is at least 16.3 MPa. The minimum forming pressure for total yielding of the inner tube 120 is 19.5 MPa.

5, when the water pressure of the water W filled in the inner tube 120 acts on the inner wall surface of the inner tube 120, plastic deformation progresses slowly as shown in FIG. 10 (a) do. 10 (b) is a data showing the stress distribution and contact pressure distribution of the inner tube 120.

 When the minimum molding pressure of 19.5 MPa is maintained for 30 seconds, plastic deformation progresses in the entire area of the inner tube 120, and the inner tube 120 is stretched so that the outer wall surface of the inner tube 120 is in contact with the outer tube 110 And is in contact with the wall surface. That is, the outer diameter d 3 of the inner tube 120 is increased corresponding to the inner diameter of the outer tube 110.

After the molding pressure is maintained for 30 seconds, the open / close valve is opened and the water W in the inner tube 120 is discharged to the outside. When the water is completely drained and the inside of the inner tube 120 is dried, both ends of the inner tube 120 and the outer tube 110 which are in close contact with each other are welded and fixed by the weld 150 as shown in FIG.

Thus, the production of the clad steel pipe 125 is completed as shown in Fig.

Here, as shown in FIG. 8, the thicknesses d3 and d4 of the inner tubes 120 and 120a are made different depending on the degree of plastic deformation of the produced clad steel pipes 125 and 125a.

The difference in the total thickness of the connecting region between the neighboring clad steel pipes 125 by the thickness difference h1 of the inner pipe is generated. This difference causes welding defects during joint welding.

In the present invention, as shown in the lower part of FIG. 10, thickness adjustment welding bands 160 and 160a are formed on both sides of the respective clad steel pipes 125 and 125a to eliminate the difference in height in order to prevent welding defect due to the thickness difference.

The thickness control welding band 160 is performed at both ends 123 and 123a of the inner tube 120 as shown in FIG. 6 to fix the outer tube 110 and the inner tube 120 in manufacturing the clad steel tube. The thickness adjusting welding band 160 is formed to be thicker than the reference welding bead and is processed in consideration of the thickness adjusting welding band 160a of the adjacent clad steel pipe.

That is, when the first clad pipe 125 and the second clad pipe 125a are to be connected to each other, the thickness d3 of the first inner pipe 120 of the first clad pipe 125, (D3 < d4) of the inner pipe 120a of the first clad steel pipe 125a and the inner pipe 120a of the first clad steel pipe 125a, So that the clad steel pipe 125a has the same thickness t.

At this time, the processing of each thickness-adjusting welding band 160, 160a is performed by using a lathe or the like to cut the relatively thick side. By doing so, jointing welding (refer to 20 in Fig. 1) is performed on the joint portion when they are aligned to the same thickness t.

If the thickness of both ends of a plurality of clad steel pipes connected to each other in this way is adjusted by the thickness adjusting welding band in the same manner, the welding defect is eliminated, and the troubles and troubles which had to cut the inner pipe can do.

As described above, the clad steel pipe manufacturing apparatus and the clad steel pipe manufacturing method using the same according to the present invention are arranged such that an inner pipe formed to be smaller in the set gap than the outer pipe is arranged concentrically inside the outer pipe, Water is supplied to form a large water pressure so that the inner tube is inflated by water pressure to be brought into close contact with the inner wall surface of the outer tube, and both ends are welded to produce a clad steel pipe.

Since the clad steel pipe according to the present invention is manufactured by applying a uniform water pressure inside the inner pipe, the bonding property between the inner pipe and the outer pipe is improved. In addition, since the inner pipe is manufactured by plastic deformation by water pressure, the productivity can be increased as compared with the conventional metal bonding method, and it is also applicable to the seamless steel pipe compared to the mechanical bonding method.

In addition, the clad steel pipe according to the present invention has thickness-adjusting welding bands formed at both ends thereof, so that the thickness of the clad steel pipe adjacent to the clad steel pipe can be controlled to be the same. Thereby, there is an advantage that the weld integrity can be ensured because there is no welding dropout caused by the thickness unevenness in the related art.

The clad pipe manufacturing apparatus of the present invention and the clad pipe manufacturing method using the clad pipe manufacturing apparatus of the present invention described above are merely illustrative and those skilled in the art will appreciate that various modifications and equivalent implementations It will be appreciated that embodiments are possible. Therefore, it is to be understood that the present invention is not limited to the above-described embodiments. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims. It is also to be understood that the invention includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.

100: Clad pipe manufacturing apparatus 110: External pipe
120: Inner alloy steel pipe 121: Weld bead
123: Both ends welding position 125: Clad steel pipe
130: External jig 140: Internal jig
141: inner frame 143: water supply pipe
145: water discharge pipe 147: internal pipe sealing support
150: welding part 151: welding rod
160: Thickness adjustment welding band

Claims (4)

An outer tube jig movably supporting the outer tube;
And an internal conduit provided to support an inner tube having an outer diameter smaller than the inner diameter of the outer tube by a predetermined gap and to supply and discharge water into the inner tube,
Wherein the outer tube is formed of a steel pipe, the inner tube is formed of an inner alloy steel,
The internal mediating unit may include:
An inner frame inserted into the inner tube to fix a position of the inner tube;
An inner pipe hermetic seal coupled to one end of the inner pipe to seal the one end;
A water supply pipe coupled to the inner frame and supplying water to the other open end of the inner pipe;
And a water discharge pipe provided at one side of the water supply pipe to discharge the water inside the internal pipe to the outside,
The outer pipe is moved so that the inner pipe is accommodated in the outer pipe, the water supply pipe supplies water, which forms a water pressure higher than the yield strength of the inner pipe, to the inner pipe, And the outer wall surface of the inner tube is tightly coupled to the inner wall surface of the outer tube so that the clad steel pipe is manufactured.
The method according to claim 1,
Further comprising a welded portion for welding and fixing both ends of the inner tube and the outer tube which are in close contact with each other by water pressure.
Forming an inner tube by welding the boundary region, the inner alloy plate not being cylindrical;
Moving an outer tube having a diameter larger by a predetermined gap than the inner tube to cover the outside of the inner tube;
Closing one end of the inner tube;
Continuously supplying water, which forms a water pressure higher than the yield strength of the inner tube, inside the inner tube;
Discharging the water inside the inner tube to the outside when the inner tube wall of the outer tube and the outer wall surface of the inner tube are in close contact with each other by plastic deformation when the inner tube is expanded by the predetermined gap by the water pressure;
And welding both ends of the inner tube to the outer tube to complete the production of the clad steel pipe.
The method of claim 3,
Wherein when the both ends of the inner tube are welded to the outer tube, the sum of the thickness of the thickness adjusting welding band formed inside the inner tube, the thickness of the inner tube and the thickness of the outer tube, Further comprising the step of machining the thickness of the thickness-adjusting weld band to be the same at both ends.

Images