JPS63252628A - Manufacture of rim of wheel for automobile - Google Patents

Abstract

PURPOSE:To improve productivity by forming a resistance welding steel pipe of specified thickness and outer diameter ratio with fin pass forming after subjecting a steel plate blank to double bending forming and full cage roll forming, then executing cutting and roll forming. CONSTITUTION:The steel plate fed out of a hot rolled coil 1 is worked by a double bending roll 2 for its edge forming and subjected to bend forming by a full cage roll 3. A forming stock is formed in cylindrical shape in order by a fin pass roll 4 to form the thin resistance welding steel pipe of t/D <=1% thickness and outer diameter ratio via an electric resistance welding machine 5 and squeezing roll 6. It is then cut after debarring, cooling and shape correction and a steel pipe 11 for manufacturing a rim is made, in succession a rim 17 is obtd. via a cylindrical body 12 for forming rim. Due to the rim 17 being manufactured from resistance welding steel pipe the man-hour is reduced and the productivity is drastically improved.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to the manufacture of wheel rims for automobiles (including motorcycles), and is directed to an automobile in which rims of good quality can be manufactured using thin-walled electric resistance welded steel pipes. The present invention relates to a method of manufacturing a rim for a commercial wheel.

Conventional technology The rim of an automobile wheel is made by cutting a steel band into a certain length, forming a steel plate into a cylindrical shape, and welding the butted parts.The resulting cylindrical body is then roll-formed 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, with rims manufactured using this method, cracks may appear in the welded area in the process after the valve hole is formed, and it takes time and effort to position the rim in order to avoid the welded area and trace the valve hole. 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 material, so weld cracks do not occur during roll forming, and valve hole drilling can be performed easily and quickly. There is an advantage that it can be done.

By the way, the conventional manufacturing method for ERW steel pipes uses a hot-rolled coil made by winding a steel band of a predetermined width into a coil shape, and continuously feeds out this hot-rolled coil, and then uses an edge mirror to shape both ends of the coil into a predetermined width. After cutting it to the desired size, it is continuously formed into a cylindrical open pipe using several sets of forming rolls, and the butt 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.

However, the t of the conventional electric resistance welded steel pipe manufactured in this way
The limit of /D (thickness t, outer diameter D) exceeds 1%, and for example, in the case of outer diameter 318.5w++n, the wall thickness is usually 3.5 to 19 bars. Rim materials for automobile wheels usually have a t/D of about 0.6 to 1.0%, but in conventional manufacturing methods, during cylindrical forming, the vicinity of the edge of the plate becomes wavy (buckling) in the longitudinal direction. Phenomenon) It is not possible to control the butt of the welded part, and welding defects are likely to occur.

The present invention advantageously solves these drawbacks of conventional forming methods, and provides a method for manufacturing an ERW steel pipe with a t/D of 1.0% or less, and for manufacturing an automobile wheel rim from this thin-walled ERW steel pipe. This is what we propose.

Means for Solving the Problems The gist of the present invention is to form a steel plate into a cylindrical shape through a forming process and a fin bath process that continuously employ double bending and full cage roll forming, and to butt the cylindrical shapes. 1 obtained by sequentially electrical resistance welding the parts
In the cutting process, a steel pipe with /[) of 51.0% (where [ is the plate thickness and D is the outer diameter) is cut into intervals having the required width to form a cylindrical body, and the cylindrical body is passed through a roll forming machine. A method of manufacturing a rim for an automobile wheel, characterized in that the rim is formed into a rim having a rim flange part, bead seams 1 to 1, and a well part.

Disclosure based on drawings of the invention FIG. 1 is a diagram showing an embodiment of the manufacturing process of the present invention.

However, after finishing the steel plates that are sequentially fed out from the hot-rolled coil (1) by binge rolls to a predetermined width using an edge mirror (not shown), the bending rigidity of the edges of the steel plates is improved to prevent edge buckling. To prevent this, double bending rolls (2) are used to form the edges of the steel plate at the initial stage, and full cage rolls (3) are used to minimize the elongation of the steel plate edges during forming. The material to be formed is bent and formed using a forming process that employs forming.
4) is successively formed into a cylindrical shape, the abutting portions of the formed steel plates are electrically resistance welded Pa (5), heated to a high temperature by passing a high frequency current, and then squeezed with a squeeze roll (6) placed immediately after. A thin-walled electric resistance welded steel pipe with t/D≦1.0% is manufactured by applying pressure and welding.

Next, the welding process generated on the inner and outer surfaces of this electric resistance welded steel pipe is completely removed using an inner and outer heat cutting device (force), and after a cooling process, the shape is corrected through a sizer (9), and the running cutting IJI (10) to obtain a type N steel pipe (11) for rim manufacturing of a certain length.

The length of this electric resistance welded steel pipe is usually 5000 to 18000 mm. The long electric IJE tube (11
) is cut into pieces at intervals having a required width to form a rim-forming cylindrical body (12).

This cylindrical body (12) is rounded by cutting the edges of both end faces or by crushing it with rollers (13),
After the edge is formed into a rounded cylinder, it is finished into a rim shape by roll forming [(14) and the rim member (1
5) is molded, and a rim (17) is formed by punching out a valve hole (16) for attaching a valve to a desired position of this rim member (15).

If the welded portion of the ERW steel pipe is heat treated using an induction heating device (not shown), the hardness of the welded portion will be reduced as shown in FIG. 2, and workability during rim forming will be improved. Additionally, an ultrasonic flaw detector (8) is provided to detect harmful defects such as cranks and scratches in welded parts.

As described in detail of the invention, according to the method of this invention, a forming method that employs double bending and full cage roll forming is applied to the steel sheets sequentially fed out from the hot-rolled coil, thereby achieving a t/D of 51.0% or less. Since long electric resistance welded steel pipes can be manufactured, it is possible to manufacture automobile wheel rims using electric resistance welded steel pipes, and productivity is improved by reducing the number of man-hours, and it is possible to fully automate the manufacturing line.

Example Using a test material having the components shown in Table 1, an outer diameter of 318.
5++un, wall thickness 3.2~L6mm (i/D:
1.0~0.5%)')') Electric R steel pipe welded part T112
Pipe production was carried out using the method of the present invention and the conventional method at a speed of 0 m/min. The results are shown in Table 2.

As is clear from Table 2, when manufactured by the method of the present invention, it is possible to manufacture pipes with a t/D of 0.6% (wall thickness 1.9 tnm). In contrast, when manufactured by the conventional method, even when 1/[) was 1% (thickness 3.2 mm>), the abutted portions were wavy and welding was impossible.

Margin below Table 1 Table 2 O: Good X: Bad

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing an example of the process for manufacturing a rim of an automobile wheel according to the present invention, and FIG. 2 is a diagram showing a comparison of hardness distribution before and after heat treatment in a welded part. DESCRIPTION OF SYMBOLS 1...Hot rolled coil, 2...Double bending roll, 3...Full cage roll, 4...Fin pass roll, 5...Welding machine, 6...
Squeeze roll, 7... Bead cutting device, 8...
・Ultrasonic flaw detector, 9...side, 10...
Traveling cutting machine, 11... Electric resistance welded steel pipe, 12... Cylindrical body, 13... Roller, 14... Roll forming machine, 15... Rim member, 16... Valve hole, 11... ·rim. Applicant: Sumitomo Metal Industries, Ltd.

Claims (1)

[Claims] A steel plate is continuously formed into a cylindrical shape through a forming process that employs double bending forming and full cage roll forming, and a fin pass process, and the butt portions of the cylindrical shape are sequentially electrically resistance welded to obtain t/D≦ In the process of cutting a steel pipe of 1.0% (where t is the plate thickness and D is the outer diameter),
An automobile wheel characterized in that a cylindrical body is formed by cutting at intervals having a required width, and the cylindrical body is formed into a rim having a rim flange portion, a bead seat portion, and a well portion using a roll forming machine. rim manufacturing method.