JPS5950915A - Manufacture of pipe of titanium, zirconium, or its alloy - Google Patents

Abstract

PURPOSE:To manufacture a pipe without causing buckling and rolling, by deciding the minimum roll diameter at the generating limit of edge buckling and the maximum roll diameter at the generating limit of rolling, and using a forming roll having the roll diameter satisfying a specified equation. CONSTITUTION:An edge stretching extent ES of a sheet-shaped hoop of titanium, zirconium, or its alloy, and an edge rising angle gamma are respectively obtained by changing the diameter phii of a forming roll in accordnce with each pipe diameter D. The minimum roll diameter phi min. at the generating limit of edge buckling is decided in accordance with each pipe diameter D basing on the presence or absence of the generation of buckling at a joined part, generating in accordance with the extent ES. And also, the maximum roll diameter phimax. at the generating limit of rolling is decided in accordance with each pipe diameter D basing on the presence or absence of the generation of rolling of a travelling hoop, generating in accordance with an edge rising angle gamma, and then a pipe having the prescribed diameter D is formed by using a forming roll having the roll diameter phii which satisfies the equation 1.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a tube made of dune, zirconium, or an alloy thereof.

When manufacturing tubes made of titanium, zirconium, or their alloy materials, a plate-shaped hoop of the material is passed between various forming rolls to form an open tube, and the joint edges extending in the longitudinal direction of the outer circumference of the tube are welded together. Methods for obtaining tubular bodies are known. Technical problems with this manufacturing method include edge buckling and rolling.

Here, edge buckling refers to the occurrence of so-called edge stretching in which the edge portion of the hoop is stretched compared to the center portion during continuous forming using forming rolls, and this stretched edge portion bends during welding and bends over t11. Edge buckling, which refers to the phenomenon of waving, makes the welded part unstable.

Also, rolling refers to the fact that the tube being formed rotates in the circumferential direction on the forming rolls about its axis, and due to this rolling, the edge joints do not run in a straight line but meander. ,
Since it deviates from the welding point, it causes welding defects.

In particular, tubes made of titanium, zirconium, or their alloys (hereinafter collectively referred to as titanium).

Thin wall compared to general pipes such as steel pipes (0.5vtyp, 0.5vtyp, 0.5vtyp.
7' is the mainstream), the yield strength is relatively high, the Young's modulus is small (approximately 1.I Edge buckling is particularly likely to occur due to factors such as insufficient roll reduction.

In addition, in most cases, high-frequency fat conduction welded pipes (
Since it is an electric resistance welded tube, there is no problem with circumferential misalignment of the edge joint, but with a titanium tube, 'I' I
Because G-welding is used, the electrode and edge join lines must be perfectly aligned, so rolling is a problem.

Therefore, conventionally, as a means to prevent the occurrence of the above-mentioned edge buckling, there is a method of increasing the diameter of the forming roll.
'Cbl), research on this point targeting general pipes has reached an advanced level.

However, as mentioned above, titanium tubes have different characteristics from ordinary tubes, so the conditions for ordinary tubes cannot be applied, and the roll diameter of titanium tube forming rolls has conventionally been determined entirely empirically. It had been. Therefore, when manufacturing titanium tubes with particularly large or small outer diameters, the roll diameter that can be used is completely unknown, and the roll diameter must be determined by hand, leading to a decrease in production efficiency. was.

Therefore, the present invention has been completed as a result of intensive research in view of the above-mentioned points, and it has been clarified that the occurrence of edge buckling and rolling is related to the edge stretch and edge rise angle of the hoop.

By determining the appropriate roll diameter based on this relationship, titanium tubes can be manufactured efficiently.

An object of the present invention is to provide a method for manufacturing a zirconium or zirconium alloy tube.

Therefore, its characteristics include titanium, zirconium,
In a method in which a plate-shaped hoop made of the alloy or the like is passed between forming rolls to form an open tube, and then the joint edges are welded to continuously manufacture the tube, the amount of edge stretch of the hoop ( g) 8) and the edge rising angle (γ) are determined by changing the forming roll diameter (φi) for each pipe diameter (D), and the buckling of the joining edge portion against the edge stretch -4J (Es) is calculated. The minimum roll diameter (φm1n) at the edge buckling occurrence limit is determined for each pipe diameter (D) from the presence or absence of edge buckling, and the rolling occurrence is determined from the presence or absence of rolling of the travel hoop with respect to the edge rising angle (γ). φ, obtained by determining the limit roll maximum diameter (φmax) for each pipe diameter (D), in = 3.5D≦φi≦1
The point is that a tube of a predetermined diameter (D) is formed using a forming roll having a roll diameter (φi) that satisfies the relationship: 1.40−φmax.

Embodiments of the present invention will be described in detail below with reference to the drawings.

The production of welded titanium tubes consists of a forming process, a welding process, and a sizing process, and FIG. 1 shows an outline of the forming process (1) and welding process (2).

In the forming process (1), a strip-shaped hoop (3) made of an alloy of titanium, zirconium, or copper alloy is passed between about 6 to 7 stages of forming rolls to form it into a cylindrical open tube (4). It is something.

The above-mentioned forming roll consists of a pair of upper and lower driven horizontal rolls, and as shown in Fig. 2, the edge part (5) of the hoop (3)
As shown in Fig. 6, the angle of the etched surface (5) can be controlled by the breakdown roll (6) that performs the initial forming up to a semicircle, and the fin plate (7) attached to the upper roll, as shown in Figure 6. It consists of a fin pass roll (8) for finishing forming and centering. Between these forming rolls are idler type side rolls (9) shown in Figure 4.
is located.

The method of forming the open tube (4) is shown in Figure 5 [A].
As shown in FIG.
There is a center forming method in which the edge locus Oo is an involute curve as shown in R], and a center forming method in which the bending radius is gradually reduced as shown in FIG. 5 [c]. Usually, setalol and flower are often used in combination of edge forming method and other methods.

The welding process (2) is similar to the forming process (1) as shown in Figure 6.
The edge joint (5) of the open pipe (4) after completion is welded in the longitudinal direction of the open pipe (4).
It consists of a squeeze roll θ1] which controls the amount of upset and the butt shape of the edge (5) in 4), and a TIG welding torch 0 placed either before or after the squeeze roll VO]).

Although not shown in the drawings, the sizing culm is used to finish the outer diameter tolerance by passing the pipe waiting to be welded through sizing rolls consisting of about four stages of upper and lower rolls each having a perfect circular hole shape.

Forming rolls () used in each of the above processes: rake-down rolls, fin pannel rolls, squeeze rolls,
At least the roll diameter (φi) of the breakdown roll (6) C, 3.5 D≦φ
i≦11.4n However, a roll having a diameter that satisfies the relationship D: diameter of the pipe to be manufactured is used.

In this way, if the forming roll diameter (φi) is set within the above range for the pipe diameter ([)] to be manufactured, buckling and rolling will not occur and high precision pipes will be produced. It is manufactured.

When manufacturing a pipe with a new diameter for which we have no prior manufacturing experience,
Since the appropriate roll diameter was unknown, it would be best to determine the roll diameter by hand or experience, but it is not a good idea to set it within the above range, and it is a trial and error process to determine the appropriate roll diameter. This reduces time loss and contributes to improving production efficiency.

Next, we will explain in detail the significance of the above-mentioned appropriate roll diameter (φj).In other words, this range is based on the first nutand break town row /l/(forming model in 61) as shown in FIG.
edge stretching (edge forming method)
En) and edge writer angle (γ) plus pipe diameter (D)
, the influence of the roll center diameter (φi) in total 91-1 The limit was determined based on the results of titanium tube manufacturing to date.

Here, Zfd shown in Figure 7 is the distance between the point where the hoop running center fin (improved hoop (3) starts contacting the lower roll (6a) and just below the roll, that is, the projected contact length), and the edge The rising angle (r) is the projected contact length Z)
This is the angle from the end of 0 to the edge vertex 03. Edge stretch 1i (Es) is the extension of the edge part (5) with respect to the hoop (3) on the center fin (0), and
・As shown in Figure 9, it is calculated geometrically, but the W1 formula is omitted.

In addition, Fig. 9 shows the shape of the hoop edge directly under the roll of the first stand, which is used in actual roll forming, is molded with plaster.
Figure 8 shows the actual measurement results in a graph.

In addition, the inside of the ring, in which the appropriate roll diameter was examined using the model of the upper and lower rolls of the first stand shown in Fig. 7, is the same as the projected contact length Z in the hoop edge shape in the actual roll forming shown in Fig. 9. ) and the edge rising angle (r) are similar to the model in Figure 7. This is because the edge stretch (En) of the first stand is larger than that of the other stands, and furthermore, the rolling is particularly affected by the symmetry of the molding in the first stand.

Now, the present inventors have found that the factor that causes edge buckling is related to edge stretch k (En), and the edge stretch (En) becomes smaller as the roll diameter (φi) becomes larger. Based on the empirical rule that rolling is more likely to occur if the roll diameter (φi) is too thick, the range of the correct roll diameter is set as the minimum roll diameter (φm1n) at which edge buckling occurs. As a result of repeated model experiments shown in Fig. 7, we assumed that the roll diameter at which the phenomenon begins to occur is within the range where the maximum diameter (φmax) [Relation only to (Es) L-1 Also, since it has been clarified that rolling is related only to the edge rising angle (r), regardless of the pipe diameter (0)), tIN is not applicable.

The experimental results are shown in FIGS. 10 and 11.

Figure 10 shows the relationship between the pipe diameter (r) and the roll diameter (φi), regardless of the edge stretch (El-1).
As r)) becomes larger and the roll diameter (φj) becomes smaller, edge stretch (En) increases, and when edge stretch (En) exceeds a predetermined value, edge buckling occurs. It shows. Figure 11 shows the relationship between the pipe diameter (D) and roll diameter (φi) with respect to the edge rising angle (γ). The angle (r) is large, and
This indicates that rolling occurs when the edge rising angle (r) becomes less than or equal to a predetermined value.

That is, it has become clear that the occurrence of buckling is related only to edge stretch (E8), and the occurrence of rolling is related only to the edge rising angle (γ).

If the relationships in Figures 10 and 11 are plotted with the pipe diameter (D) on the horizontal axis and the roll diameter (φi) on the vertical axis, the rolling occurrence limit and buckling occurrence limit are illustrated as shown in Figure 12. Nashi, φ. =3.5D, φm3X” 11.4D
It became clear that there was a relationship.

Therefore, the appropriate roll diameter (
If the range of φi) is expressed by the formula, φmin ” 3.5D≦φi≦11.4o=also Tla
It becomes X.

1. The forming roll to which the present invention is applied is at least a breakdown roll, but a fin pass roll,
It may be applied to squeeze rolls or sizing rolls.

As detailed above, the present invention has the following advantages: - When determining the appropriate roll diameter that does not cause buckling or rolling, the range can be instantly determined for the manufacture of titanium tubes to which the manufacturing conditions of membrane tubes cannot be directly applied. This makes it possible to improve production efficiency and manufacture high-precision, high-quality pipes.

Furthermore, the present invention is significant in that it has been clarified that buckling and rolling are related to edge stretch and edge rise angle, and that the relationship has been elucidated.

[Brief explanation of the drawing]

Fig. 1 is a schematic process diagram showing the manufacturing process of titanium tubes, Fig. 2 is a sectional view showing a breakdown roll, Fig. 3 is a sectional view showing a fin pass roll, Fig. 4 is a sectional view showing a Zide roll, Figure 5 is a schematic diagram showing the tube forming method, Figure 6 is a plan view showing the welding process, Figure 7 is an explanatory diagram of the model experiment,
Figure 8 is a graph showing the locus measurement results of the hoop edge directly under the top and bottom rolls of the first stand, Figure 9 is a perspective view of the hoop directly under the rolls of the first stand made of plaster, and Figure 10 shows the result of edge stretch. Pipe diameter and low) L/
FIG. 11 is a graph showing the influence of the tube diameter and roll diameter on the upper edge angle. FIG. 12 is a schematic diagram of the proper roll diameter range of the roll for forming titanium tubes. (3)...Hoop, (5)...Ecchi, (61...
・Forming roll (〕. Rake down roll), E8...Work sojisutre・sochi, γ...Edge rising angle, D...Pipe diameter, φi...
- Diameter of center of lower roll. 1

Claims (1)

[Claims] 1. A method of continuously manufacturing a tube by passing a plate hoop made of qp, zirconium, or its alloy between forming rolls to form an open tube, and then welding the joint edges. The hoop edge stretch amount (circle) and etch rise angle (γ) are determined by changing the forming roll diameter (φl) for each pipe diameter (D), and the difference between the fat edge stretch ti (E8) and From the presence or absence of buckling at the joining edge, determine the minimum roll diameter (
n1n) is determined for each pipe diameter (1)), and from the presence or absence of rolling of the traveling hoop with respect to the edge rising angle (r), the maximum roll diameter (4) at the rolling occurrence limit is determined.
) + 118
A method for manufacturing a titanium, zirconium, or alloy tube thereof, characterized in that a tube of a predetermined diameter (L) is formed using a forming roll having a roll diameter (φi) that satisfies the relationship X.