KR0130527B1 - Built steel pipe electric pole and method for producing the same - Google Patents

Abstract

This invention relates to a built-up steel pipe utility pole with a receiver of each joint forming an expanding pipe and a method of making the same. The inventive pole has receivers of expanding pipe and is of multilayered built-up structure to ensure economical efficiency and operation efficiency with bending stress of more than reference strength. In order to do this, one end of a small diameter's utility pole assembly is formed as a receiver of an expanding pipe that can be joined to an insertion of a large diameter's utility pole assembly. In this utility pole assembly its steel pipe's expanding part is heated at 200deg.C, and a drawing oil with kinematic viscosity of 90 and over on the basis of 50deg.C is first applied to a relatively small diameter dice tomove it forward to the expanding part's inside. After that the surface of the steel pipe is heated at 300 to 450deg.C to move the dice of the small diameter backward and then cooled at a room temperature by using the relatively large diameter dice through the same procedure.

Description

Prefabricated steel pipe pole and manufacturing method

1 to 5 illustrate an embodiment of the present invention.

1 is an installation state of the assembled pole.

2 and 5 are manufacturing process diagrams.

3 is a partially cutaway side view of the die.

4 is an enlarged view of the approach portion of the dice.

6 is a partially separated perspective view of the insertion hole and the water polo as another embodiment of the present invention.

7 is its cross sectional view.

8 is an explanatory diagram of a conventional drawing die

* Explanation of symbols for main parts of the drawings

1a, 1b, 1c, 1d: Jeonju Organization 3: Insertion

5: expansion tube 6: water polo

7: fixing bolt 61: guide protrusion

62: engaging projection 301: insertion hole

The present invention relates to a method for manufacturing a prefabricated steel pipe pole in which the water duct of the coupling portion is expanded.

Conventional prefabricated steel pipe poles are welded to both ends of several poles (approximately 3 to 4) of different pole diameters, and each flange part is fastened with bolts and nuts to form one assembled steel pipe pole. Forming. Such conventional steel pipe poles have an outer diameter that decreases toward the tip, whereby a group of about 3 m is assembled into 3 to 4 or other required numbers in a mountainous area or a vulnerable area in which vehicles are difficult to enter. In each group, the so-called pieces and insulator stand, which are scaffolding, are separately welded and plated. These steel pipe poles shall meet the conditions that do not involve deformation when a 500 kg / cm 2 load is applied to the joint.

However, the steel pipe pole is not only expensive to manufacture, but also has a lot of difficulty because it is necessary to fasten bolts and nuts by hand by hand in the air by using a triangular crane (gin) when assembling in the field. There is a risk of losing its function as a pole due to weakness of strength. In other words, when an external force such as wind pressure is provided above the design value after installation, a phenomenon in which the bolted flanged joint is destroyed may occur.

The present inventors have attempted to solve the above problems, but the form of the water pipe of the coupling portion to form a shaft tube (縮 管), but the strength and economical efficiency is low and shows a large turbulence in the manufacturing method is finally adopted. The reason is as follows.

First, when a certain portion of an existing steel pipe is axially piped, an outer diameter of 100 mm or more is usually used in the form of extrusion or drawing processing, and in the case of a steel pipe having an outer diameter of 100 mm or less, a swaging machine can be used. .

However, in order to form prefabricated poles, steel poles with at least outer diameter of 190.7mm (t: 5 to 6.4) must be used, and the strength given to the joining part must be large, and the taper angle of the part must be large so that other poles are joined to the apparatus of the pole. Since the insertion hole of is able to be closely fitted in appearance or strength, at least four dies which can gradually reduce the outer diameter of the steel pipe are obtained in order to obtain a pole body that can be assembled without such play and having such conditions. It is necessary to precisely control the dies, so that a large plastic processing machine must be manufactured separately without using an existing extruder, a drawing machine, or a swaging machine.

Only then can the Jeonju organization be manufactured at a given strength (about 500㎏ / ㎠) without cracking, biting, or dimensional change in the shaft forming the shaft.In this case, the mold cost, installation cost, manufacturing cost, etc. are enormous. This is a complicated problem. It is an object of the present invention to provide a method of manufacturing steel pipe poles which can be assembled in a multistage manner and have a water pipe to have a standard strength and secure economical and workability.

In order to achieve the above object, the present invention consists of a water port forming an expansion pipe that can be coupled to an insertion hole of a large diameter electric pole in one end of a small diameter electric pole, and the expansion portion of the electric pole is heated to around 200 ° C. to a primary molding die. 50 ° C. The kinematic viscosity of 90 or more is applied to advance the tube into the expansion tube, and the primary tube is expanded. The tube tube is re-heated to 300 to 450 ° C. for secondary expansion using a secondary molding die and cooled at room temperature.

Embodiments of the present invention will now be described with reference to the accompanying drawings.

FIG. 1 shows a state in which four electric poles 1a, 1b, 1c, and 1d having different outer diameters and a base body 2 buried underground are combined to form one assembled pole. Each of the electric poles (1a, 1b, 1c, 1d) is a structure that the outer diameter becomes smaller toward the top, each of its length is about 3m, the minimum outer diameter is about 190.7mm, the maximum outer diameter is 267.4mm. The pole pole groups 1a, 1b, 1c, and 1d actually constitute one set of three to four or more. In addition, each pole organization (1a, 1b, 1c, 1d) is formed in the water pipe and the insertion port is expanded at both ends. As an example, when the coupling portion is described based on two poles 1b and 1c coupled in the middle, one end of the pole diameter pole 1c can be coupled to the insertion hole 3 of the pole pole pole 1c. The water port 6 which consists of the expansion pipe part 5 which has the taper part 4 is formed.

On one side of the expansion pipe 5 of the water port 6, a nut 8, to which the fixing bolt 7 can be fastened, is welded to the insertion hole 3 of the large-diameter pole pole body 1b. After inserting the water polo (6) of the fixing bolt (7) is to complete the coupling.

6 and 7 show another embodiment of avoiding the rotation by the fixing bolt 7 when the insertion portion 3 and the water polo 6 is coupled as described above.

In this case, the guide projection 61 is formed in the longitudinal direction in the insertion hole 301 of the large diameter pole pole 101b, and the guide protrusion 61 of the insertion hole 301 is formed in the water duct 601 of the pole diameter pole pole 101c in the small diameter. And a coupling protrusion 62 which can be combined with the guide protrusion 61 to match the coupling protrusion 62 to insert the opening 601 of the small diameter pole pole 101c into the insertion hole of the large pole pole pole 101b. When inserted into the 301, the rotation of the coupling direction between the electric poles (101b, 101c) by the guide projection 61 and the engaging projection 62 is not to occur.

2 to 5 are shown to explain the manufacturing method of the present invention. Explain this. 2 shows the equipment for expanding the steel pipe 21 and the steps of the first process, the steel pipe 21 is fixed to the jig 23 installed on the surface plate 22 and for expanding the expansion pipe A. In a system consisting of a hydraulic pump 24 and a hydraulic cylinder 25 having a force of about 200 tons and two dies 27 which can be screwed into the ram 26 of the hydraulic cylinder 25 and differ in outer diameter. It can be expanded by.

As shown in FIG. 3, the die 27 has an approach 28, a bearing 29, and a relief 30, which are introduced into the expansion pipe A, formed on the outer surface at a constant angle. The thread portion 31 that can be screwed with the end of the ram 26 of the cylinder 25 is formed.

The angle θ1 of the approach 28 is larger than the relief 30 θ2, and in particular, the bearing 29 has an extreme point at which the maximum inner diameter of the expansion pipe A is formed at a point opposite to the advancing direction to the expansion pipe A. (B) is formed. This is formed in the opposite direction to the pole 83 of the bearing 82 given in the conventional drawing die 81 shown in FIG. 8 on the approach 83 side. This is an important means for avoiding the rupture or scratch of the expansion part A in connection with the oil drawn later.

Therefore, the die 27 as described above is fastened to the ram 26 as shown in FIG. By means of heating to around 200 ℃ to give ductility.

Next, drawing oil is applied to the surface of the die 27. This drawing oil uses Korea Lube Co., Ltd.'s brand name D-300S, which is specially produced with a synthetic oil (mixture of polar adsorption agent and extreme pressure additive) having a viscosity of 90 cSt (kinetic viscosity) of 50 ° C or higher. This resulted in scratches and local ruptures on die surface and inner surface of steel pipe with drawing oil of 90cSt or less based on the existing kinematic viscosity of 50 ° C. will be.

When drawing oil is applied to the die 27 as described above, the hydraulic cylinder 25 is operated as shown in FIG. 5 to carry out the primary expansion work for advancing the die 27 into the expansion part A and retreating 300 to 350 mm. After completion of the primary expansion, the secondary molding die having a larger diameter than the primary molding die (the outer diameter is determined in consideration of the shrinkage rate when cooled after expansion) is re-expanded, as illustrated in FIG. The surface of the expansion pipe A is heated to 300 to 450 ° C. (surface temperature) by a heating means such as an automatic oxygen welding machine, and then the die 27 is advanced to expand the water pit 6 by the bearing 29 and die. When the (27) is retracted and cooled at room temperature, the inner diameter is gradually contracted, which is the same as the outer diameter of the insertion hole 3.

As mentioned above, when the expansion pipe (A) is heated to below the recrystallization temperature, the drawing oil is applied to the die, and the expansion pipe is expanded twice, so that the expansion pipe (A) is ductile, so the expansion work is quick and there is no defect. However, since there is no change in the organization of the steel pipe, it is possible to maintain the rigidity of the steel pipe (material).

The completed electric pole of the present invention was tested by a bending strength tester, the maximum strength of the pole is 1.016㎏ / ㎠, the conventional flange is significantly improved than the strength of steel pipe pole (500㎏ / ㎠) of the food good stiffness In terms of economics, it is easy to overcome the costs and process difficulties to take the form of shafts, and the relatively simple facilities and processes resulted in improved workability and appearance quality. .

Claims (2)

After heating the expansion part of the steel pipe to around 200 ° C, apply drawing oil having a kinematic viscosity of 90 ° C or higher to the primary molding die and advance it into the expansion part to expand the primary, and expand the primary expansion part 300 to 450 The method of manufacturing a prefabricated steel pipe pole after reheating using a secondary molding die having a diameter larger than that of the primary molding die after applying the above-mentioned drawing oil after heating to ℃. 4. The method of manufacturing a prefabricated steel pipe pole according to claim 3, wherein the bearings of the primary forming die and the secondary forming die are formed with poles forming the maximum inner diameter of the expansion pipe at points opposite to the advancing direction of the expansion pipe.