JPS63224814A - Manufacture of weld steel pipe for wheel rim - Google Patents

Abstract

PURPOSE:To manufacture a rim with a simple work at low cost at manufacturing the wheel rim by forming a steel strip slit at prescribed intervals into a cylinder, after welding butted parts then heat treating, followed by finishing the outer circumference. CONSTITUTION:The steel strip 2 fed out of a hot rolled coil 1 is slit 7 in constant pitches by a press 6 consisting of a punch 4 and die 5. Both lug parts are cut by a edge miller 9 to finish into a prescribed width, then formed into a cylindrical open pipe by plural pairs of forming rolls 10. After the butting parts of this open pipe are heated and softened by an electric resistance welding machine 11, pressure welding is performed by a squeeze roll 12. Nextly, after cutting to remove flashes generated on the inner and outer surfaces of the welded part by bead cutting machine 13, the weld zone is heat treated by a high-frequency induction heating apparatus 14 to soften into the same softness of a parent material, then the weld zone is cooled by a cooling apparatus 22. After that, the outer circumference is finished precisely into the prescribed dimension by a sizer 15, the cut into the prescribed length by a cutting machine 16 to manufacture the weld steel pipe 17 for the rim.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to the manufacture of welded steel pipes used for manufacturing wheel rims for vehicles such as automobiles (including two-wheeled vehicles), industrial vehicles, construction vehicles, and agricultural machinery. The present invention relates to a method for manufacturing a welded steel pipe that allows easy division and cutting of a rim-forming cylindrical body.

Conventional technology The rim of a vehicle wheel is made by cutting a steel band into a certain length, forming a steel plate into a cylindrical shape, welding the butted parts, and then roll-forming the cylindrical body to form a rim flange. It is generally manufactured by a method of forming a section, a bead seat section, and a well section.

However, rims manufactured using this method tend to have cracks in the welds during the process of removing the valve holes, and it takes time and effort to position the rim in order to avoid the welds and handle the valve holes. There are drawbacks.

Furthermore, if the hardness of the welded part is higher than that of the base metal, the welded part or its vicinity may break or cause processing cracks.

In order to eliminate these drawbacks, welded steel pipes (ERW steel pipes)
There is a method of manufacturing a rim by dividing and cutting into predetermined lengths to make a cylindrical body for the rim, and processing this cylindrical body with a roll forming machine. Rims manufactured using this method can be heat-treated to make the welded part almost as hard as the base metal, so weld cracks do not occur during roll forming, and valve hole drilling is simple and quick. There are advantages to doing so.

By the way, the conventional manufacturing method for welded steel pipes uses a hot-rolled coil made by winding a steel strip of a predetermined width into a coil shape, and continuously feeds out this hot-rolled coil, and then edges the ends of the coil to a predetermined width using an edge mirror. After cutting, it is continuously formed into a cylindrical open pipe using several sets of forming rolls, and the butted parts are successively joined using electric resistance welding.
After heat-treating the welded part and subsequently cooling the welded part, the outer diameter is finished to a predetermined accuracy in a sizing process.

Conventionally, a welded steel pipe manufactured in this manner was used and the welded steel pipe was divided into predetermined lengths to obtain a cylindrical body for the rim.

Problems to be Solved by the Invention When the welded steel pipe obtained as described above is used for the rim of a wheel, when the steel pipe is cut into predetermined short lengths, the cylindrical body for the wheel rim is Diameter is 200-700mm
Because of its large size, if you try to cut it by cutting, fusing, or other means, it will be extremely difficult to cut, and it will take a long time to meet the production pitch of the rim, or the cut surface will be extremely rough, making it unsuitable for practical use. Furthermore, in order to shorten the cutting time, the cutting capacity must be significantly increased, resulting in an increase in the size of the device and a significant increase in cost, making it unsuitable for practical use.

Means for Solving the Problems This invention proposes, as a means for solving the above-mentioned conventional problems, a method for manufacturing a welded steel pipe in which cuts are made in advance for dividing and cutting at a constant pitch. Cuts are made at a constant pitch at intervals equal to the material width of the rim in the continuously fed steel strip, and the strip with the cuts is continuously formed into a cylindrical open pipe. are sequentially joined by electric resistance welding, the welded part is heat treated (annealed, normalized) to make the hardness of the welded part equal to that of the base metal, then the welded part is cooled, and the outer diameter is reduced by a sizing process. This is a method to obtain a welded steel pipe that is finished to a predetermined precision and has cuts for dividing and cutting at intervals equal to the material width of the rim in the longitudinal direction of the pipe. As mentioned above, the welded steel pipe manufactured by this method already has cuts for dividing and cutting at a constant pitch in the pipe itself, so dividing and cutting to obtain a cylindrical body for rim forming can be easily and quickly performed. Cost reduction is also possible.

Disclosure based on Drawings of the Invention Fig. 1 is a manufacturing process diagram showing one embodiment of the invention, Fig. 2 is a perspective view illustrating how to make cuts in a steel strip, and Fig. 3 is a perspective view illustrating how to cut a steel strip.
The figure is also a longitudinal cross-sectional view showing the cross-sectional shapes of various cuts.

That is, the punch (4) placed after the uncoiler is applied to the steel strip (2) that is sequentially fed out from the hot rolled coil (1).
The cut (7) is made by the press (6) consisting of the and Gui (5).
are inserted at a constant pitch with a length having the required rim material width. The steel strip with cuts is Edge Mirror (
After both ears are cut and finished to a predetermined width by the machine 9), it is continuously formed into a cylindrical open pipe by several sets of forming rolls (10), and an electric resistance welder ( Squeeze roll (12) placed immediately after heating to high temperature by passing high frequency current by 11)
Apply pressure to join.

The welding ridges generated on the inner and outer surfaces of the welded steel pipe thus formed are completely cut and removed by the inner and outer surface bead cutting device (13). Welding with burr removed #
! The tube is heat-treated (annealed or normalized) only at the welded portion by a high-frequency induction heating device [14], so that the hardness of the welded portion is reduced to a value approximately equal to that of the base material. Subsequently, after the welded part is cooled by a cooling device (22), the welded steel pipe is finished by a sizer (15) so that the outer diameter is within tolerance, and then cut to a predetermined length by a cutting machine (1B), usually 50 mm.
00 to 18,000 mm> to obtain a welded steel pipe for rim (17). In the figure, (21) is an ultrasonic inspection machine for detecting harmful defects such as cracks and flaws in welded parts.

The electric resistance welded steel pipe (17) for a wheel rim thus obtained has cuts (7) at equal intervals except for the welded portion, as shown in the figure.

In addition, as for how to make the cut (7), for example, see Figure 2 (
As shown in a), the ears (8) at both ends have widths (
Either leave the edge of H) continuous and make a cut (7) only in the center of the steel plate, or cut the edge of width (for width) only on one ear (8) as shown in Figure (b). It can be left continuous and have a cut (7) from the center to the other ear (8), or it can have a cut (7) across the entire width. In addition, the cross-sectional shape of the cut (7) is shown in Figure 3 (a).
) as shown in the figure (19) or
A V-shaped groove (20) is formed by cutting only the top surface as shown in b), or a V-shaped groove (20) is formed on the top and bottom surfaces as shown in the same figure (C). , or a shape that is slightly connected at the center of the plate thickness.

Regarding the method of making the above-mentioned cuts and the cross-sectional shape, the most efficient combination is adopted from the viewpoint of ease of processing with the forming roll (10), accuracy of welding, ease of cutting, etc. Note that the length of the cut should be adjusted as appropriate depending on the board thickness and board width.

Effects of the Invention As explained above, according to the method of this invention, cuts can be made in the longitudinal direction at regular intervals, leaving only a small edge of the edge or the center of the plate thickness. As a result, the manufactured electrical resistance welded steel pipe has a cut in it, leaving the weld and its vicinity, so when this steel pipe is cut into short lengths to be used as wheel rim material, it is cut at the cut part, so it is difficult to cut. The cutting process can be carried out in an extremely short time, does not require any special cutting means, and has excellent effects in that costs can be reduced.

Exception: When manufacturing an electric resistance welded steel pipe with a diameter of 318.5 mm and a wall thickness of 2.5 to 4.0 m 1 Tl at a welding speed of 30 m/min, the steel strip (
The test was carried out under the conditions shown in Table 1, with a plate width of 1000 mm>, cross-sectional shape and cut length as shown in Table 1, and the steel strip could be made into a pipe without breaking from the cut due to the tensile force applied during pipe making.

In this example, the remaining thickness in the case of the notch shape was 1 mm.

[Brief explanation of drawings]

Fig. 1 is a manufacturing process diagram showing one embodiment of the present invention, Fig. 2 is a perspective view illustrating how to make cuts in the steel strip of the present invention, and Fig. 3 similarly shows the cross-sectional shapes of various cuts. FIG. 1...Hot rolled coil, 2...Strip steel, 4...Punch, 5...Gui, 6...Press, 7...
Cut, 8...Ear part, 9...Edge mirror, 1
0... Forming roll, 11... Electric resistance welding machine, 12... Squeeze roll, 13... Internal and external bead cutting device, 14... High frequency induction heating device, 15... Sizer, 16... ... Traveling cutting machine, 17... Welded steel pipe for rim, 19... Slit shape, 20... Concave groove, 21...
・Ultrasonic inspection machine, 22... Cooling device. Applicant: Sumitomo Metal Industries, Ltd. Kanai Wheel Industry Co., Ltd.

Claims (2)

[Claims] (1) A steel strip with cuts made at a constant pitch at intervals equal to the material width of the rim in the longitudinal direction was continuously formed into a cylindrical open pipe, and the butt parts were sequentially joined by electric resistance welding. After that, heat treatment is applied to the welded part, and then the welded part is cooled, and then the outer diameter is finished to a predetermined accuracy using a sizer, and cutting cuts are made at intervals corresponding to the material width of the rim in the longitudinal direction of the pipe. A method for producing a welded steel pipe for a wheel rim, characterized by obtaining a pipe. (2) The method for manufacturing a welded steel pipe for a wheel rim according to claim 1, wherein the cut is a cutout, a slit, or a groove.