JPS59209425A - U press tool for uoe steel tube manufacturing process - Google Patents

Abstract

PURPOSE:To smoothen preprocessing for O press forming and regular welding that follow U forming and to improve the quality of a steel tube by specifying a tool used for U press bending in manufacturing UOE steel tubes. CONSTITUTION:A tool 1 used for U press forming is so made so that the range of angle theta on the bottom 1a is 100-150 deg., and the radius of U-shaped steel plate sprung back after U press has a radius of curvature R that becomes the bending radius nearly corresponding to succeeding O press, and the radius of curvature on both sides 1b, 1b of the tool 1 that continue from the bottom 1a is made to a radius R1 which is smaller than the radius of curvature R of the bottom 1a by at least 30%.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the creation of a U-press tool for UOE@Lightning manufacturing process, and improves the workability of O-press, temporary press, etc. when performing 0177 bending in the UOE steel pipe manufacturing process. The purpose is to improve the quality of the product obtained by main welding by making welding pre-treatments such as cleaning and drying of the welded part easy and complete.

As one of the methods for manufacturing steel pipes, it is well known that the UOE method is particularly suitable for obtaining large steel pipes. That is, in this method, the end of the raw steel plate is marked, then 0177 bent, then O-pressed and welded, but conventional steel pipe manufacturing using this method has various problems regarding 0177 bending. However, it is not easy to obtain the desired steel pipe smoothly and properly. If the radius of the U-curve of the lid is extremely small, the seam portion 1Oa will overlap during handling of the raw tube 10 after zero pressing, as shown in Figure 1 (,), and the cleaning and drying of the seam portion 10a will be difficult In addition to being incomplete, during the subsequent tacking work, the seam portions 10a, 10a must be pushed out from inside the pipe and the tacking must be performed while correcting the lap state, which significantly impedes work efficiency and results in inferior quality. I have no choice but to become something like that.

Also, even if this U bending radius does not overlap with the 0 press as described above, if it is smaller than the appropriate range, the 0
As shown in Figure 1(b), the seams are brought into close contact by pressing, and the pre-welding treatment such as cleaning and drying is incomplete, resulting in defects such as blowholes and slag entrainment in the welded parts. This is likely to occur. On the other hand, if the U-bending radius is large as shown in Figure 1 (c), excessive springback will occur after O-pressing, and tacking may require excessive force to butt the seams and may not be suitable. It is difficult to correct and clamp the material into a correct shape, and especially if it is excessive, the springback force will cause the material 10 to stick tightly to the 0-grace die 11 as shown in FIG. It becomes extremely difficult to take out and carry out, and furthermore, it becomes difficult to carry it into the O-press die 11. Of course, tack attachment inevitably involves problems such as time.

The present invention has been devised after repeated studies in view of the above-mentioned circumstances, and by making the above-mentioned zero-curve press tool a specific one, the above-mentioned disadvantages can be effectively eliminated and favorable workability can be achieved. Through this process, we succeeded in accurately obtaining product steel pipes with excellent quality. That is, one example of such a U press forming mechanism is as shown in FIG. A saddle plate 4 supported by a link mechanism 3 is provided between the
On the saddle plate 4, a bunch 1 that is pushed and pressed down by a cylinder 2 is disposed oppositely, and the bunch 1 is pushed against the wood board 10 carried onto the brake rolls 5, 5 by the carrying means 6.
As the process is shown step-by-step in FIG. The middle part of the steel plate 8 is pressed down together with the saddle plate 4, and the bunch 1 passes through the line of the brake rolls 5, 5 and is pushed down, thereby shaping the raw steel plate 8 into a U shape.
After bending, the brake rolls 5, 5 are pushed inward to push both ends of the raw steel plate 8 inward.As for overpressure, the degree of overpressure will be determined by taking into account the springback of the steel plate. This spring;
The strength of the material is directly proportional to the strength of the material, and inversely proportional to the thickness of the material.If the thickness of the material is large, the springback strength is:
Even if the same shape is to be obtained, it is necessary to change the pressing conditions depending on the strength and plate thickness. The present inventors have confirmed that the influence of the U-press tool on the case of the housing is also large, and that when the bending radius is large with the press tool, the springback will also be large, and furthermore, it is constrained by the press limit, The curve is an angle, and the joining angle range of the material plate relative to the circumferential surface of bunch 1 is the third
As shown in (d) of the figure, the maximum angle is approximately 230°, so in order to form a U-shape, the springback amount must be 50°.
It was confirmed that it is necessary to determine the tool shape so that the That is, regarding this springback weighing foot, the following formula (I) is shown, for example, in Machinery Engineering Handbook 17-58.

However, here, Δθ: Spring-kink angle θ as shown in Figure 4: Initial bending angle M: Bending moment at initial bending E: Elastic modulus, second moment of inertia, thickness of material surface t ,
If the length is t, then the value is tt3//12 ρ: Radius of the neutral plane during bending Note that M in equation (I) can be approximated by assuming that the material is a 141j plastic body, as shown in Fig. 5. As in, the length of t is calculated as follows: =tX.

M=tf ayV-d'j=! Therefore, since the maximum bending angle during U press is θmax = 230°, in order to form a U shape, it is necessary to make Δθ 50° or less. be.

By the way, in general, the UOE image, 1. J tube thickness range is 6 to 5
0wn, and its strong luni has a yield stress of 30 to 70
K9/rmn, and its outer diameter is 400 to 1500 φ, which corresponds to this. The range of the Ullll radius is given by formula 1. Since it is sufficient to save the range of approximately 150 to 70 Cbtrm, the results of the study using the following equation (II) can be summarized as shown in FIG. 6.

Δθ−3・1・Hill・θ (II) t Here θ: 2300 E: 21000 Km! σy: 30 to 70 t: 6.4 to 50 mn ρ: 150 to 700 In other words, in this figure, a diagonal line corresponding to the bending radius ρ is found at the bottom, and from the intersection of the diagonal line and the material plate strength σy upward The springback angle is found by drawing a perpendicular line to the line and intersecting it with the diagonal line of the plate thickness t. However, in this case, in the case of an immediate radius face, the springback limit angle is 50°. From the relationship, it is clear that considerable limitations occur in the thin to medium thickness range.

Note that in order to make a U steel plate that can be loaded into a zero press machine, the distance between the width d at the upper end of the U steel plate and the width of the die forming surface is F(D-d)≧203, as shown in FIG. There is peace of mind that comes with the value of

However, in the past, over-pressing was done in consideration of the amount of springback of the steel plate, and the width of the opening end was formed within the width range of the die forming surface in order to make a U steel plate that could be loaded into an O-press machine. has been thoroughly studied and formed with a punch suitable for this purpose, but the punch is one for each outer diameter size, regardless of the thickness or strength of the steel Buddha. In order to bend and form high-strength, thin-walled copper plates, the radius is usually extremely small.In this case, the U-bending radius generally tends to be small. As a result, the seam portion lags or at least the seam portion is not sealed, and a preferable welding pretreatment is performed.F#,'<, Welding defects are inevitable, and tacking and other operations must be done by analogy. Therefore, the inventor Tera first investigated the appropriate range of seam spacing due to springback after O-pressing, and found that 5.
~30 tonnage, and at this level, good tacking can be achieved efficiently, and the seam can be cleaned and dried accurately, resulting in excellent quality of the welded part. Later, such an appropriate amount of springback 5 to 3
Further consideration of the U-shaped shape to obtain 0 mm revealed that the above-mentioned disadvantages (
Difficulty matching the seam due to overlap or close contact of the seam, or excessive springback, or failure to take out the seam from the 0-grace die, etc.) at the bottom of the U-formed steel plate.
It depends on the average radius R after springback in the range of 0 to 1200, and it is possible to obtain the best preposition after O-press when the half-way of the 0-press die and the radius of this part match. Through many experiments, it has been confirmed that the permissible range is roughly ±25 fog. This allowable range may be expanded depending on the O press conditions, but in order to realize economical and efficient operation, K should be ±25m.
It is appropriate to keep it within the range.

The reason for the above relationship is that the degree of influence of whether the seam portions 10a, 10a are closed or opened after 0 greasing is large in the portions away from the portion 10a. , each part B in Fig. 8,
C.

If the angle between D and the seam part is dθ, and the distance from each part to the seam part 10 & groove is L, then the amount of displacement of the seam part can be expressed as L-dθ, and parts B, C,
The degree of influence is greatest in the order of D. Therefore, in such a U steel sheet subjected to O-pressing, the state of B, C or D@ far from the seam portion 10a is the same as the seam portions 10a, 10 after 0-pressing.
It is clear that this has a decisive influence on the state between a. Furthermore, the deformation process of the U steel plate during this O-pressing is as shown in Fig. 9, but while the BC part in Fig. 8 described above only undergoes deformation that conforms to the O-pressing surface 41, the upper part (on the seam side) has a radius γ smaller than its radius l, as shown in Fig. 10 during the O-press deformation process.
The shape of the bridge is pressed as a whole to fit the die, so the result will be the same regardless of the shape as long as the part near the seam is not extremely smaller than the minimum radius (γ) that can be bent during the pressing process. becomes.

Next, when considering the U press bending radius d8, where the die radius is the part BC in Figure 8 after the O press, as shown in Figure 10, d8 - ρ' (θ - Δθ) = ρ・θ − a'(1-stop gradient θ-2θ E-, so 1=1-moxibustion (I[) ρ' ρ E-t.If the O press die radius is 100, then the first
As shown in Figures 1 and 412, D.

Figure = ρ 100 t, therefore ρ = 100-100, and if the U press punch radius is R, then ρ--=R-
Therefore, from the above formula (■), where ρ=R0, the following is obtained. As an example, the 0 press die radius (wo) is 503
The calculation results for the sieve are shown in FIG. 13, and it is clear that the radius of the bunch 1, which is a V-press tool, varies greatly depending on the plate thickness and strength.

Therefore, we developed the above-mentioned steel plate made by Suzu Linda Bakku Co., Ltd., and created a Y steel plate that can be over-flessed and loaded into an O-press machine, and also has a U-press tool ( Examining the punch), it is found that in a simple circular press tool with a radius as shown in Fig. 44, a thin p
'1bI due to Susringbank limit as shown in the figure
The seam portion 10a cannot be press-formed into a suitable U-shaped steel plate due to the fact that it cannot be bent.

This results in an upwardly opening shape with a wide space between IUa and cannot be loaded into an O press machine. Also, assuming that a U-shaped shape is possible, the U-shaped @ width d of the plate as shown in Figure 15.
Since the diameter of the O-braces is equal to
), making charging difficult or impossible. Therefore, in the present invention, as shown in FIG. It has a radius of curvature R, which is a bending radius approximately equivalent to the press die radius, and
The radius of curvature of the two a-regular parts 1b, 1b of the tool 1, which is 100 to 150 degrees at the m part and continuous to the bottom part 11L, is smaller than the radius R mentioned above and has a radius R1. Based on the results of field trials, the value is set to be in the range of R = 0.3R to 0.9R, and furthermore, both tools with such a radius R of 4° ] The angular range θ1 of the part is 40° or more, and by using such a specific U press tool, all of the above-mentioned requirements are satisfied (- U press for always preferred O press forming) It is possible to appropriately obtain m=.When R is thicker than 0.9R, the same disadvantage as in the circular press tool shown in Fig. 14 is recognized, and when it is 0.3R or less, it is preferable. This makes it difficult to obtain U-pressed copper plates.

According to the present invention as described above, U-bending in the UOE steel pipe manufacturing process is precisely performed as a state in which subsequent O-brace forming, subsequent tack bonding, or pre-treatment for main bath welding can be carried out smoothly and appropriately. Therefore, it is possible to manufacture the desired steel pipe efficiently and smoothly, and the quality properties of the welded part and other parts are sufficiently improved. This is a highly effective invention.

[Brief explanation of the drawing]

The drawings show the technical solution of the present invention.
The figure is an explanatory diagram summarizing the inconvenient conditions in the O-press and subsequent pipe-forming process due to inappropriate U-bending radius, Figure 2 is a front view showing an overview of the U-press forming mechanism, and Figure 3 is an explanatory diagram showing step-by-step the forming process of a raw steel plate by this U-brace forming mechanism, Fig. 4 is an explanatory diagram showing the relationship between spring bank angles, and Fig. 5 is the bending moment I during initial bending in the calculation formula. - Explanatory diagram for M, 6th
The figure is a diagram summarizing the bending radius, material plate strength, and the relationship between the plate thickness and spring bank angle for practical UOE steel pipes. Figure 7 shows a U-shaped steel plate that can be loaded into an O-press machine. Figure 8 is an explanatory diagram showing the relationship between the influence of each part of the U-shaped steel plate during O-forming, and Figure 9 summarizes the deformation process of the U-shaped @ plate during O-press forming. The explanatory diagram shown in Figure 10 shows that the bottom of the U-shaped steel plate after O-bracing is 0.
11 and 12 are explanatory diagrams of the U press bending radius, which is the press die radius.
The figure is a diagram summarizing the relationship between the U press tool radius, plate thickness, and material @ plate strength for an O press die radius of 503 cm. Figure @14 is an explanatory diagram of a simple circular U press tool. The figure is an explanatory diagram of the disadvantageous relationship when the width of the U-shaped steel plate and the diameter of the O-press die are equal, and FIG. 16 is an explanatory diagram illustrating the configuration of the U-press tool according to the present invention in cross section. In these drawings, 1 is the punch which is the U press tool, 1a is the bottom, 1b is the both sides, 2 is the cylinder of the U press tool, 3 is the link mechanism, 4 is the saddle grate, 5 is the brake roll, and 8 is the The material steel plate, 10 is the raw pipe after O-pressing, 10a is the seam part thereof, and 11 is the O-pressing die. Zheng / purchasing CC) (d) 2nd purchase 10 countries and a half

Claims (1)

[Claims] The radius of curvature of the U-shaped steel plate where the bottom 1oo-x5o0 yoke circumference of the tool used in the U-forming process to obtain steel pipes by bending and forming steel plates by the UOE method is approximately equivalent to the subsequent O-press radius. A UOE @ U press for tube manufacturing process, characterized in that the radius of curvature on both sides of the tool continuous to the bottom is at least 30% smaller than the radius of curvature of the bottom. tool.