JPS6130226A - Bend working method for metallic tube - Google Patents

Abstract

PURPOSE:To prevent the thickness deviation of a tube and the flatenning by arranging the shaft core of a presser roller on the same vertical line with the shaft core of a main roller as well as heating the inner side of a bend part to the prescribed temp. CONSTITUTION:A metallic tube 2 is arranged on the main roll 1 of a bender and the inside semicircle 2b of the bend part is heated to the plastic zone temp. of the blank material. A backing plate 3 is placed on the upper part of the tube 2 and a presser roller 4 is brought into contact thereupon and a rough bend is performed by rotating a bandle 5 along the roll 1 as well as rotating the roll 1. The final bend is then performed with arranging the main roll 1 and presser roll 4 so that the shaft core comes on the same vertical line by replacing the roll 1 with the roll having the diameter equivalent to the bend diameter. In this case the inner periphery 2b of the bend part is re-heated upto the plastic zone temp. The thickness deviation and flatenning are reduced with this method and the bend work at optional angle is enabled as well.

Description

[Detailed Description of the Invention] The invention of the present application relates to a method for bending metal tubes. Conventionally, when bending metal tubes, a method of inserting a core material into the tube and bending it with a bender machine has been adopted. However, in this method, after the tube is bent, the tube becomes flattened and oriented, which causes a deterioration in the quality and properties of the tube itself.

The invention of the present application & Go aims to provide a method for bending metal tubes that eliminates the above-mentioned drawbacks, and the gist thereof is to heat the inner half of the bent portion of the metal tube to a predetermined temperature and place it on the main roll of a bender machine. A metal tube is placed on the outside of the bent portion of the metal tube, and a metal fitting is placed on the outside of the bent portion of the metal tube. Multiple pressing rollers are placed in contact with the corresponding metal fitting, and the tip of the metal tube is placed on the main roll while rotating the main roll. Transfer and press along the outer periphery, and at this time, move the roller so that the axis of the main roll and the axis of the presser roller that comes into contact with the fitting on the metal tube are arranged on the same vertical plane. This is a metal tube bending method characterized by bending the metal L tube to the required angle by dividing the diameter of the main roll into stages, maintaining the roundness of the tube, and making it easier to bend the metal tube. It can be bent to any angle without facing the same direction.

Hereinafter, the method of the present invention will be explained in detail based on embodiments shown in the drawings.

Figure 1 & Go, the metal tube (
2), and place the inner half circumference (
2b) is heated, a metal fitting (3) is placed on top of the main roll (1) and the top of the tube (2), and a pressing roller (4) is placed on the top of the metal fitting (3). . Furthermore, the metal fittings (
8) This shows a state t+1 in which the metal tube part (2c) at the tip of the handle is gripped by a handle (5) formed in a split shape.

The heating temperature when heating the inner half circumference (2b) of the metal tube (2) is set to be within the plastic region of the material (600 to 950°C). Therefore, in the state shown in Figure 1, the metal tube (
2], the inner half circumference (2b) of the bent portion (2a) is heated to a state where it is plastically deformed, and is ready to start bending. However, do not insert the textured core material into the gold #4 W f2).

From the state shown in Figure 1, rotate the main roll (1) in the clockwise direction of the arrow, and rotate the inner periphery (
2b) along the outer periphery of the main roll (1) and rotate the handle (5) to roughly bend the metal tube (2) little by little to about 140 degrees (see Figure 2). At this time, Metal tube (2)
The metal tube (2) is sent forward while the metal fitting (8) placed above is also moved in the direction of the arrow.

In this case, it is important to bend the main roll (1) using a diameter that is slightly larger than the final bending diameter of the gold pA tube (approximately 13 times the metal 9M diameter). As a result of various experiments by changing the positional relationship between the press roller (4) placed on the stopper fitting (3) and the main roll (1), we found that the metal tube (2) was Perfect bending can be achieved by arranging the axis (1a) of the roll (1) and the axis (4a) of the presser roller (4) placed on the stopper (8) on a vertical line. That's the result. In this case, the final bending is performed using the metal tube bending diameter (one time the metal tube diameter) set for the final round as the diameter of the main roll (1). Also, select any part you want to bend here (2a
) Reheat the inner half circumference (2b) of the tube (2b) at 600 to 950'C. At this time, of course, as shown in the figure, the axis (1a) of the main roll (1)
and the shaft center (4) of the presser roller (4) on the stopper fitting (8).
a] are arranged so as to be located at the same vertical level.

Table 1 shows the results of a bending test using the method of the invention of the present application and a bending test using a commercially available bender machine, and the two were compared based on the flatness and wall thickness of the metal tube.

Table 1 However, as is clear from Table 1, when using the bending method of the present invention, the wall thickness reduction rate is extremely small, 1/6 to 1/8 of that of commercially available bender machines. The flatness is less than half that of commercially available bender machines, making it possible to bend metal tubes in a state close to a perfect circle. By using a slightly larger roll diameter and gradually bringing it closer to the final set roll diameter, the wall thickness reduction rate and flattening ratio can be brought closer to 0%.As described above, according to the present invention, metal The inside of the bent part of the pipe is heated in the plastic region, the axis of the presser roller on the pad is placed on a perpendicular line to the axis of the main roll of the bender machine, and the diameter of the main roll is changed. This method is ideal for bending serpentine metal tubes such as boiler tubes, as it allows you to freely bend the metal tube to the desired angle. I can maintain my temper. Therefore, the quality and performance of metal tubes can be improved to a much higher level than with conventional bender machines.

[Brief explanation of drawings]

FIG. 1, FIG. 2, FIG. 6, and FIG. 4 are explanatory diagrams each showing an embodiment of the bending method for 134' ft of gold according to the method of the present invention. In the figure, fIM main roll (2): metal tube (8): stopper metal fitting (4): holding roller (6): handle

Claims (1)

[Claims] 1. Heat half the inner circumference of the bent part of the metal tube to the required temperature and place it on the main roll of the bender machine, place a metal fitting on the outside of the bent part of the metal tube, and apply heat to the corresponding metal fitting. The tip of the metal tube is moved and pressed along the outer periphery of the main roll while rotating the main roll with a plurality of pressing rollers in contact with each other, and at this time,
The rollers are arranged so that the axial center of the main roll and the axial center of the presser roller that comes into contact with the fitting on the metal tube are arranged on the same vertical line, and the diameter of the main roll is adjusted in stages. A metal tube bending method characterized by bending the metal tube at a required angle.