JPH0518659B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing column materials for steel structures and the like.

Beam joints (joint parts) of circular pipe columns in steel structures are formed thick or provided with annular protrusions in order to ensure required joint rigidity. FIG. 8 shows an assembly column made by joining circular pipes 45, 45 and a thick-walled circular pipe 46 that will become a joint part by butt welding of the pipe end faces, and a beam 42 attached to the outer surface of the thick-walled circular pipe 46. FIG. 9 shows an example in which circular pipes 48 having annular projections 47 are welded together to form an assembled column, and the flanges 42, 1, 42 of the beam 42 are attached to the annular projections 47, 47. , 1 is applied and welded and joined.

The column shown in FIG. 8 above is assembled using drawn steel pipes, welded steel pipes, etc. as the circular pipes 45 and 46, and the thick-walled circular pipe 46 forming the joint part and the circular pipes 45 and 4 on both sides thereof are assembled using drawn steel pipes, welded steel pipes, etc.
Since the thickness of No. 5 changes rapidly at the welded joint W, there is a drawback that stress concentration and a decrease in proof strength due to local deformation are likely to occur during use. Furthermore, it is undesirable that there are two weld lines in a portion that causes stress concentration.

On the other hand, a centrifugally cast tube is used as the circular tube 48 used to assemble the column having the annular projections 47, 47. Figure 10 shows the casting method. Reference numeral 1 denotes a mold, and a large diameter portion 7 is provided at one end of the inner surface of the mold. Reference numeral 8 denotes a liner fitted into the large diameter portion 7, and the step wall surface 81 of the liner 8 and the step wall surface 71 of the large diameter portion 7 define an annular groove 9 that goes around the inner peripheral surface of the mold. There is. In addition, 5 and 5 are hot water stopper bands (end plates) fitted to the openings at both ends of the mold.
It is. When molten steel is poured into the mold 1 while rotating about its centerline, a circular tube 48 having an annular protrusion 47 formed by an annular groove 9 forms under the action of centrifugal force as shown in the figure. available.

The centrifugal force casting method is suitable for mass production, and enables the production of circular tubes (column materials) as assembled column constituent units at low cost. Further, since the column assembled using the circular pipe as a constituent unit has only one weld line W at the joint, it is advantageous in terms of strength compared to the column shown in FIG. 8.

However, in the centrifugal casting according to the casting method described above, assembly of the mold for forming the annular groove 9 requires a lot of time and effort, and productivity is extremely low. Wall surface 8
No. 1,71 is easily deformed and cracked due to thermal stress during casting, and has a short service life. Moreover, the positions of the annular protrusions 47, 47, the spacing between the protrusions, the protrusion height, etc. necessary for the joint part change each time depending on the design of the column, so the mold and liner must be adjusted until the drawings are finalized. There are drawbacks such as the inability to start production and therefore significant difficulty in meeting delivery dates.

Further, since the above-mentioned conventional column joint part has a shape that bulges outward from the surfaces of the straight pipe parts above and below, the entire bulging surface of the joint part is covered with the beam 42. Regardless of the case, partially, for example, 2
If beams are connected only in one direction or three directions,
The bulging surfaces other than the parts where the beams are joined remain exposed and can be seen directly, resulting in an unsightly appearance.

Furthermore, since the joint section of a conventional column has a circular external cross-sectional shape, when welding the beams together, an arc-shaped bevel is formed on the end face of the beam to match the convex peripheral surface of the joint section. must be formed. Welding and assembling the beam to the joint part of the convex surface is extremely troublesome work, and the productivity is also very low.

The present invention solves the above-mentioned problems regarding the cylindrical column, and as shown in FIG.
On one end side, the inner surface bulges inward, and the outer surface has a flat surface 2 included inside the extended circumferential surface of the straight pipe part.
To provide a method for manufacturing a column material in which a reduced diameter portion 21 having a diameter of 2 is formed through a tapered portion 25.

The method for manufacturing the column material of the present invention is to use a centrifugally cast tube having a thick walled large diameter portion that bulges outward at one end of the straight pipe portion as a blank tube, and to draw the thick walled large diameter portion. A column material having the above shape is obtained by reducing the diameter.

The present invention will be explained in detail below.

As shown in FIG. 2, the centrifugally cast pipe used as the raw pipe in the present invention has a thick-walled, large-diameter part that bulges outward through a tapered part 13 at one end of a straight pipe part 11. It has 12. The straight pipe portion 11 and the thick large diameter portion 12 have the same inner diameter, and the tapered portion 13
is an inner circumferential surface 14 and a tapered surface 15 forming a conical surface on the outer circumference.
It is defined by.

The centrifugally cast tube 10 is cast according to the casting method shown in FIG. 1 is a centrifugal casting mold, 2 is a straight pipe forming part in the mold, 3 is a large diameter part, and 4 is a tapered surface. End plates 5, 5 are fitted into the openings at both ends of the mold 1, and a predetermined amount of molten steel is poured into the mold from the pouring hole 6 of the end plate 5 under rotation about the central axis of the mold. A molten metal cylinder 10' having a predetermined layer thickness is formed along the inner wall surface of the mold by the action of centrifugal force and is solidified to obtain a cast pipe having the shape shown in FIG.

Next, the centrifugally cast pipe 10 is made into a blank pipe, and its thick large diameter portion 12 and tapered portion 13 are subjected to drawing processing using a press, a roll, or the like. The drawing process of the raw tube 10 may be performed in the as-cast state after being pulled out from the mold, or may be performed after being subjected to subsequent heat treatment such as normalizing treatment. Through this drawing process, the diameter of the thick large diameter part 12 and tapered part 13 of the raw pipe is reduced, and as shown in FIG. 1, the inner surface is bulged inward while maintaining the required wall thickness. A flat surface 22 is formed on the outer surface. The plane 22 is formed to be included inside the extended surface of the circumferential surface of the straight pipe portion 11 . In addition, in the drawing process, in order to avoid a sudden change in the level difference between the outer surfaces of the thick-walled reduced-diameter part 21 and the straight pipe part 11 having the flat surface 22, the gap between the thick-walled reduced-diameter part 21 and the straight-tube part 11 is A tapered surface 23 is formed on the outer surface. In addition,
The inner tapered surface 24 is formed in the process of diameter reduction by drawing. These tapered surfaces 23 and 24 provide a tapered portion 25 between the thick diameter reduced portion 21 and the straight pipe portion 11.

Figure 4 shows an example of a column material obtained by drawing a raw pipe. The thick reduced diameter portion 21 has a substantially rectangular outer shape consisting of four flat surfaces 22. The corner 26 between the planes may be a curved surface that curves in the circumferential direction as shown. The plane 22 of the thick-walled reduced diameter portion 21 is the surface to which the beam is joined, and therefore the thick-walled reduced-diameter portion 21
is formed into an arbitrary polygonal shape having a number of planes corresponding to the number of beams to be joined. Figure 5 is 2
This is an example of a column member having a thick diameter reduced portion 21 that forms two flat surfaces 22 and the other portion is a circular arc surface 27 that curves in the circumferential direction. Depending on the direction of beam connection,
Two planes 22 may be formed in two orthogonal directions. Further, when the number of beams to be connected is one, only a portion of the thick-walled diameter-reduced portion may be formed into a flat surface, and the other portion may be formed into an arcuate surface. In addition, the curved surface 26 and the circular arc surface 27 at the corner between the two planes in the above example are formed to be included inside the extended circumferential surface of the straight pipe portion 11 or to substantially coincide with the extended circumferential surface. However, it may protrude outward from the extended circumferential surface within a range that does not impair the aesthetic appearance in use. Furthermore, if there is a step between the curved surface 26 or arcuate surface 27 at the corner and the inner circumferential surface of the straight pipe section 11, a tapered surface 28 may be formed.

A necessary number of the pillar members 20 are prepared, and the pillars are assembled as a unit by welding the end faces on the thick-walled diameter-reduced portion 21 side and the end faces on the straight pipe portion 11 side together. FIG. 6 shows an example in which a beam 42 is joined to a joint portion 41 of an assembled column 40 manufactured in this manner. The beam 42 is joined to each plane 22 of the joint section 41. Further, there is only one weld line W in the joint portion 21.

According to the method of the present invention, a centrifugally cast pipe is used as a raw pipe,
A column material as a unit of an assembled column can be obtained by subjecting a portion thereof to a simple forming process by drawing, so it is cheaper than a manufacturing method using a drawn steel pipe or the like. Moreover, the inner surface shape of the mold used for centrifugal casting of the raw pipe is a relatively simple shape defined by the straight pipe forming part 2, the large diameter part 3, and the inclined surface 4 therebetween. Since a complicated casting method as shown in the figure is not required, there are no problems such as troublesome mold assembly or early damage to the mold.

In addition, in a column in which the column material according to the present invention is assembled as a unit, the joint part has a shape smaller in diameter than the outside diameter of the straight pipe part by drawing, and the outer surface of the joint part and the straight pipe part are Since the difference in level from the outside surface is very small, it has a superior aesthetic appearance when in use compared to conventional pillars that have a joint section with an outwardly bulging shape. Moreover, the joint part has the required wall thickness, and the thickness gradually changes from the thick wall part to the straight pipe part, and there is only one weld line at the joint part, so it is not strong. But it's excellent.

In addition, since the joint part of the beam at the joint part is flat, the end face groove shape of the beam can be linear, and it can be adjusted to the convex curved surface of the joint part, as in the case of joining a beam to a conventional column. There is no need to form an arcuate groove. Therefore,
It is easy to insert and assemble beams between columns, and welding is also easy.

Furthermore, the pillar materials manufactured by the present invention can be used not only as pillar materials for buildings, etc., but also as concrete blocks for constructing marine structures (e.g., sea walls, breakwaters, piers, off-shore breakwaters, mooring facilities for aquaculture). Used as pile material in combination with. It is particularly useful as a pile material when the pile driving continuous block method (PBS method), which has been attracting attention recently, is applied.
In this PBS construction method, as shown in FIG. 7, at the bottom of the pile 20, a wedge receiver 52 suspended from a PC steel wire 51 has a truncated conical inner wedge 53 and an inclined inner circumference that matches the outer circumferential surface of the wedge receiver 52. Outer wedge with faces 5
This is a construction method in which a concrete block 55 is stacked on top of the wedge, and a wedge effect is gradually created by the weight of the stacked concrete blocks, and the specified concrete block is set. Afterwards, when the PC steel wire is tensioned, the block and stake become an integral structure. In this case, the point part of the pile 20 is a stress concentration part, so it needs to be thicker than other parts in order to withstand stress, and it needs to be thicker than other parts to withstand stress. A polygonal shape can produce a much stronger wedge effect. From this point of view as well, the column material in which a polygonal thick wall portion is formed according to the present invention is suitable as a pile material for the PBS method.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway front view schematically showing the shape of the column material after drawing according to the present invention, Fig. 2 is a partially cutaway front view illustrating the raw pipe used in the present invention, and Fig. 3 is an axial cross-sectional view showing the method of centrifugal casting of raw pipes,
4 and 5 are perspective views illustrating the column material obtained by the present invention, and FIG. 6 is a perspective view illustrating the usage status of a column assembled as a unit from the column material obtained by the present invention. FIG. 7 is a sectional view illustrating another usage mode of the pillar material obtained by the present invention, FIG.
FIG. 9 is a partially cutaway front view showing the joint part of a conventional column, and FIG. 10 is a sectional view showing a conventional centrifugal casting method for column material. 1... Centrifugal casting mold, 2... Straight pipe forming part, 3...
...Large diameter part, 10...Made pipe (centrifugally cast pipe), 11...
...Straight pipe part, 12...Thick walled large diameter part, 13...Tapered part, 20...Column material of the present invention, 21...Thick walled part, 2
2...plane, 25...tapered part, 40...assembly column, 41...joint part, 42...beam, W...welding line.

Claims (1)

[Claims] 1 At one end of the straight pipe part, a thick-walled reduced diameter part is formed through a tapered part, the inner surface of which bulges inward, and the outer surface of which has a plane included inside the extended circumferential surface of the straight pipe part. In this method, a centrifugally cast tube having a thick-walled large-diameter portion that bulges outward through a tapered portion on one end side of a straight pipe portion is used as a base tube, and the thick-walled large-diameter portion is and a method for manufacturing a column material, characterized in that by drawing the tapered part, the diameter is reduced while maintaining a required wall thickness, the inner surface bulges inward, and a flat surface is formed on the outer surface.