JPS5927649B2 - U press method in steel pipe manufacturing by U, O, E method - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to the creation of a U-pressing method for manufacturing steel pipes using the U, O, E methods, and aims to provide a U-pressing method that can expand the range of possible U-pressing. It is.

U,, O) Kaiser-type, Burson-type, and other types of U press equipment are used for manufacturing E steel pipes, but the common features of the conventional U press methods using these equipment are: 1. The key point is that the steel plate is formed into a U-shape using multiple presses.

FIGS. 1a and 1b show a conventional U-pressing process using such Kaiser-type U-press equipment. First, as shown in FIG. 1, a steel plate 2 placed on brake rollers 1, is gradually pushed and bent by the descending U-punch 3, and as the U-punch 3 further descends, the U-punch 3 hits the saddle 4 through the steel plate 2 and presses it down, and as the saddle 4 descends, the link 5 , 5, the brake rollers 1 and 1 move toward each other, and press and bend the steel plate 2 to perform a U-press.

In this type of conventional U press using a single press,
Although it is possible to obtain a reasonably appropriate U-press shape, the equipment used to perform U-plus naturally has a press capacity limit, and for this reason, conventional U-pressing using such equipment With this method, there was a problem in that it was not possible to form a thick plate exceeding a certain limit or a proper U-press molding with high strength. The present invention was devised in view of the current situation, and is a method that allows proper U-pressing of steel plates with a lower load than conventional methods, and also allows thick-walled or high-strength steel plates to be U-pressed. Its purpose is to provide.

In order to achieve such an object, the present invention
Instead of performing U-pressing in one press, U-pressing to form a steel pipe into a U-shape is performed in multiple times, and the multiple presses are performed by changing the gap interval of the brake roller or the saddle height, or both. As a result, the pressing contact point of the brake roller against the steel plate is located closer to the outside in the width direction of the steel plate as the press advances, and this makes it possible to perform U-pressing with a lower load than before. .

Next, embodiments of the present invention will be described based on the drawings.

FIG. 2 shows a Kaiser type U press equipment, in which 3 is a U punch that presses down the steel plate 2 from above, 4 is a saddle located below the U punch 3, and 6 and 6 are the saddles 4 and 6. Brake garters 1, 1, which are linked together via a link 5 and move in the direction of the arrow in the figure, are brake rollers attached to each of the brake garters 6, and the steel plate 2 is moved from the state shown by the broken line in the figure to the U-punch 3 as shown in the figure. When the U-punch 3 further descends from the state shown in the figure, the steel plate 2
hits the saddle 4, and from this moment the brake garters 1, 6 move toward the steel plate 2 via the link 5, and the brake rollers 1, 1 in contact with the steel plate 2 push and bend the steel plate 2, thereby performing a U-press. In the present invention, such a series of U-pressing steps is carried out in multiple steps while changing the press conditions. Specifically, the change in the press conditions means that the brake roller 1 shown in FIG. Gap G (G=L
O-t-k-Wpl where LO: span, t: thickness of steel plate, k: radius of brake roller, Wp: K of U punch width
) or the height of the saddle 4, or both of these, and by changing these, the present invention improves the brake roller 1,
The pressing contact point of one steel plate 2 with respect to the steel plate 2 is made to be closer to the outside in the width direction of the steel plate 2 than that of the succeeding one, and for this reason, the gap G of the brake roller 1 is increased during the preceding press. The saddle height can be made larger or the saddle height can be lowered.

3 to 5 show examples of changing the press conditions when the present invention is configured as a two-time press. In FIG. 3, the brake rollers 1 and 1 are changed in the first press. Position it in the state shown by the broken line in the figure, 2
In the second press, the press is placed in the state shown by the solid line, and the gap is changed by (ΔG) between the two.

This position adjustment is performed by moving the brake roller 1 forward and backward in the U-punch 3 direction on the brake gutter 16 using a device not shown. In addition, in Fig. 4, the saddle 4 is set at the height shown by the broken line in the figure in the first pressing press, and the height shown by the solid line in the second pressing press, and the saddle height is changed by (△H) between the two. This height change is performed by, for example, inserting a liner or the like into the upper surface of the saddle 4. Furthermore, Figure 5 shows the above 3rd figure.
This is a combination of those shown in Figures and Figure 4, and the gap change (△G) and the saddle height change (△H) are made between the first press and the second press. .
In changing the press conditions shown in Figures 3 to 5 above,
In both cases, the pressing contact point of the brake rollers 1, 1 with respect to the steel plate in the first pressing press is closer to the outside in the width direction of the steel plate than in the second pressing press, and as a result, the pressing contact point of the first pressing press is closer to the outside in the steel plate width direction. It becomes possible to obtain a larger moment than that of the second pressing press. The present invention has the above-described configuration, and as shown in FIGS. 7a and 7b.
As shown in , in the first pressing press, the forming angle θ1 (the angle formed by the horizontal tangent to the brake roller and the steel plate) becomes 60〈θ, and in the second pressing press, the forming angle θ2 becomes 800〈θ2. It is molded to have a diameter of 110 mm.

FIG. 6 shows the relationship between the forming load and forming angle in the two-time press according to the present invention in comparison with the conventional one.

In the figure, the broken line A shows the forming curve according to the conventional method, and according to this forming method, there are two peak load points, point A, and point A2, in the process of U pressing by one press. If the press capacity limit of the equipment is Pc, U press forming will be impossible. On the other hand, in the U press according to the present invention, the shape is formed as shown by the solid line B in the first pressing press, and the load is released at point B3, but the peak load points are at point B, point and point B2. The load is considerably lower than the maximum load at point A, point A2 of the method, and even the press limit capacity of the equipment. Steel plate is B
It is formed to 602 x θ and x 900 at three points. Then,
The conditions are changed based on any one of those shown in FIGS. 3 to 5, and a second press is performed, whereby the steel plate is formed as shown by the chain line C.

That is, since the steel plate has already been formed up to point B3 in the first pressing press, the substantial forming in the second pressing starts from point C, and after forming up to point C2, the load is removed. However, the peak load point is only point C1. The steel plate is formed at point C2 at 80°C until <θ2>110°. As described above, according to the U-press method of the present invention, as is clear from the comparison with the peak load points of the conventional method, ie, the a1 point and the A2 point, the U-press can be performed with an overall low load. Therefore, it is understood that if the pressing capacity is kept constant, it is possible to U-press form a steel plate with a thicker wall or higher strength than with the conventional method.

The table below shows specific examples of the two-press press according to the present invention in comparison with conventional methods. In the above table, Examples 1 to 4 are cases in which conditions are changed based on FIG. 3, Examples 5 and 6 are conditions changed based on FIG. 4, and Examples 7 to 9 are cases in which conditions are changed based on FIG. 5. This shows that.

As is clear from this table, it can be seen that according to the method according to the present invention, a load reduction effect of about 20 to 30% compared to the conventional method can be obtained no matter which condition is changed. In addition, in each of the above embodiments, the present invention was configured as a U press method using a two-time press.
It goes without saying that U-press molding can be performed by pressing three or more times.

According to the U-press method according to the present invention as described above,
When U-pressing a steel plate using a multiple press press, by changing the gap interval and/or saddle height of the brake rollers, the pressing contact point of the brake rollers 1, 1 on the steel plate in the preceding press can be adjusted accordingly. Since the subsequent press is placed closer to the outside in the width direction of the steel plate than the connection point, the maximum load in U press forming of the steel plate can be significantly reduced. It is possible to perform U-pressing on thick-walled or high-strength steel plates that exceed a certain limit, and has an excellent industrial effect in that the range of U-pressing possible with existing equipment can be greatly expanded.

[Brief explanation of drawings]

FIGS. 1a and 1b are explanatory diagrams showing a conventional U-pressing process. FIG. 2 is an explanatory diagram schematically showing the U press equipment. 3 to 5 are explanatory diagrams showing aspects of changing the U-pressing conditions in the U-pressing method according to the present invention.
FIG. 6 shows the relationship between the load and forming angle of the U-press method according to the present invention in comparison with the conventional method. FIGS. 7a and 7b are explanatory diagrams showing the shape of the steel plate after one-time pressing and two-time pressing in the present invention. In the figures, 1 indicates a brake roller, 3 indicates a U-punch, and 4 indicates a saddle. .

Claims (1)

[Claims] 1 When U-pressing a steel plate using a multiple press press, by changing the brake roller gap interval and/or saddle height, the pressing contact point of the brake roller with the steel plate in the preceding press can be adjusted to the following. U in steel pipe manufacturing using the U, O, E method, characterized in that the pressing contact point of the brake roller on the steel plate in the press is located closer to the outside in the width direction of the steel plate.
Press method.