JPS6156794A - Manufacture of welded tube including powders - Google Patents

Abstract

PURPOSE:To weld safely and obtain high quality products by detecting the temperature of weld zone and the speed of weld tubes and controlling the quantity of power by the detection signal through a welding temperature control circuit. CONSTITUTION:The speed of revolution of a motor 3 for coiling is controlled to maintain the bulk surface of powders in a welded tube at the range of constant controls between an opening part of a powder supply tube 6 and a starting point of coiling the metallic tube so that it can follow the falling flow speed of powders. Accordingly, the speed change of the welded tube brings on the change of weld temperature. Therefore, the temperature of weld zone is detected by a weld temperature detector 38 and the speed of the welded tube is detected by a welded tube speed detector 36. These detection signals are sent to a weld temperature control circuit 37, from which the power quality of the electric source for welding is controlled to be in the range of weld temperature, which can secure high quality welding regularly.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention relates to flux used in semi-automatic and fully automatic arc welding, and various powders for denitrification, deoxidation, etc. used in refining and casting of molten steel. The present invention relates to an apparatus for manufacturing a welded tubular body made of a friendly metal.

[Prior art]

Conventionally, as a method for manufacturing a powder-filled welded tubular body, there is a method disclosed in Japanese Patent Publication No. 58-187300, namely: (1) A spool wound with a long metal tube is placed on a vibrating table. A method of filling a metal tube from a powder t-hopper while vibrating a long coiled metal tube wound around the spool. Bending and forming the strip from both sides of the center force,
Next, the ends of the bend are joined by welding to form a tubular body, and a powder supply pipe is inserted between the bent ends of the unwelded part to reach the tubular body immediately after welding, and the powder supply pipe is inserted into the tubular body to be continuously formed. When continuously supplying powder from the powder supply pipe, a method has been proposed in which the powder is supplied while the metal strip and the tubular body are held horizontally or inclined.

However, in the case of method (1) above, if the powder contains particles that compensate for differences in specific gravity or particle size, the particles will separate due to the difference in specific gravity or particle size, etc., resulting in a uniform particle distribution. In addition to the quality drawback of not being able to fill the powder in the same state, there is also the problem of extremely low efficiency because it takes a huge amount of time to fill the entire length of the long coiled metal tube wound around the spool. There is.

In addition, in the case of method (2) above, it is difficult to densely fill the tubular body with powder while keeping the tubular body production line level, and unfilled voids occur, making it difficult to obtain high quality products. Moreover, when winding up or transporting a powder-filled welded tubular body, the inside of the tubular body...! In addition, when the tubular body manufacturing line is tilted in the method (2) above, there is no means for controlling the welding speed of the tubular body with respect to the powder charging speed. It is difficult to reliably and stably maintain the powder deposition surface at a predetermined position within the tubular body immediately after welding, and if the powder deposition surface is too close to the welding part, the powder will change in quality due to the welding heat, causing a There is a problem that gas is generated from the powder, and furthermore, if the powder deposition surface is too far away from the welding part, the powder filling becomes incomplete and it becomes difficult to confirm the filling state.

[Purpose and structure of the invention]

The purpose of the present invention is to provide a method for manufacturing a powder-filled welded pipe that can eliminate all the problems of the conventional method described above. The welded pipe 7 is formed by sequentially bending the strip 1 in the width direction and sequentially welding the bent edges, and the powder supply conduit 6 is connected from the opening of the unwelded bent portion of the metal strip 1. 1. By inserting the powder into the welded pipe Z through the conduit 6 and supplying the powder into the welded pipe Z, the powder is rolled up. In a method for manufacturing a coiled powder-filled welded tube, when the welded tube is tilted at an angle greater than the angle of repose of the falling powder and the powder is supplied falling into the welded tube, the surface on which the powder is deposited is the welded part. so that it is always maintained within the defined control range from the rear conduit opening to the start point of welded pipe winding.
The feeding speed of the solution/liquid pipe is synchronously controlled according to the amount of powder supplied, while the temperature of the welding zone and the welding pipe speed are detected, and the detection signal is used to control the power of the welding power source via the welding temperature control circuit. A method for manufacturing a powder-filled welded pipe, characterized in that the T-weld temperature is controlled to always maintain a sound welded part.

〔Example〕

Next, the invention will be explained in detail using fully illustrated examples.

The drawing shows one embodiment of the present invention, which shows a strip feeding spool 2 around which a long metal strip 1 such as a steel strip is wound, and a tubular body in a winder 11 provided diagonally below the strip feeding spool 2. On the inclined tubular body manufacturing line between the take-up spool 4, there are guide rolls 12 facing both sides of the metal strip 1, and a first forming process that sequentially bends and forms the metal strip 1 so that it has a circular cross section. A forming roll group consisting of rolls 13 to 4th forming roll 16, a welding tool 5 connected to a welding power source 17 and consisting of an fC welding power supply terminal, and a pressure welding roll 18 are sequentially arranged from above to below, The spool 4 is rotated by a variable speed electric motor B via a reduction gear (not shown).

The inlet of a powder feeder 21 having an electrically controlled feed adjustment device M is connected to the outlet of a hopper 20 containing powder 19 for welding flux or other purposes via an on-off valve 22, and The upper part of the powder supply conduit 6 is connected to the outlet of the powder feeder 21 via an on-off valve 26, and the powder supply conduit 6 is connected between the third forming roll 15 and the fourth forming roll 16 and immediately before the completion of the tubular body. is inserted obliquely downward along the center of the tubular body between the bent ends of the metal strip,
In addition, the lower end of the powder supply conduit 6 is arranged at a slightly lower level than the pressure roll 18.

The powder feeder 21 may include, for example, a cylindrical cage 7/da having a powder inlet and a powder outlet, a powder feeding screw housed in the cage, and a screen whose speed can be adjusted freely. A drive device such as a DC motor that rotates the motor is used.

A powder upper limit position detector 8 is arranged at a position close to the outer surface of the welded pipe 7 at a level slightly below the lower end of the powder supply conduit B, and below the powder upper limit position detector 8. In this case, a powder accumulation surface monitoring detector 24 and a powder lower limit position detector 9 close to the outer surface of the welded pipe 7 are arranged in sequence, and each of the detectors 8°9.24 is, for example, the welded pipe 7. A detector consisting of a gamma ray projector, a gamma ray sensor, etc., which are sandwiched and opposed to each other, is used.

Each of the detectors 8, 9.24 is connected to an input section of a detection signal processing circuit 250, and an input section of an output processing circuit 26 is connected to an output section of the detection signal processing circuit 25; The output section of the powder level display section 2
7 and powder level record X! Total 28 is connected to a motor control circuit 29 that controls the rotation speed of the motor B for rotating the take-up spool, and the detection signal processing circuit 25. The output processing circuit 26 and the motor control circuit 29 constitute the motor rotation speed control device 10.

The powder supply conductor H6, electrical IJ machine rotation speed control device 1
0. Guide roll 12. Forming roll groups 16 to 16, pressure rolls 18. The powder feeder 21 and the like are supported by an inclined support 30, which is pivotally connected to a base 61 by a horizontal shaft 32, and which is connected to the inclined support filter O and the base 31.
It is connected to the support table through a hydraulic pressure/slider 56 for adjusting the inclination of the support table, and it is also possible to set the optimum inclination angle according to the properties of the powder.

In order to maintain the powder accumulation surface 65 in the welded pipe within a certain control range between the opening of the powder supply conduit B and the metal pipe winding start point, the winding electric motor is set to follow the falling flow velocity of the powder. The rotational speed of B is controlled, and the resulting change in the speed of the welded pipe causes a change in the welding temperature. Therefore, in this invention, the temperature of the weld zone is detected by the welding temperature detector 38, and the welding tube speed (welding tube feeding speed) is detected by the gold bath liquid tube speed detector 36vc, and these detection signals are used to detect the welding temperature. The temperature is sent to the control circuit 37, and the welding temperature control circuit 67
The amount of power input to the welding power source is controlled to keep the welding temperature within a range that always ensures sound welding quality.

As a control factor for automatic control of welding temperature, we only failed to detect the temperature of the weld immediately after welding and to detect the speed of the welded tube, but in order to improve the accuracy of welding temperature control, changes in the plate thickness of the gold scrap plate and other factors were considered. The following welding temperature control method may be adopted by adding the factors that affect welding.

The starting end of the welded tube 7 is closed by an appropriate means before being wound around the tubular body take-up spool 4, and after the filling of powder into the tubular body is completed, the end of the welded tube 7 is welded by an appropriate means at the end of the powder filling. The tube 7 is closed.

When this invention is fully implemented, the means for welding the bent end of the metal strip may be high frequency welding or low frequency welding.

Welding means such as plasma welding, 'HG@contact, and direct current electric welding may be employed.

Note that the present invention also includes a case where a powdered substance is used instead of powder to increase the efficiency of feeding into the pipe.

〔Effect of the invention〕

According to this invention, when the welded pipe is tilted at an angle of repose greater than the angle of repose of the falling powder and the powder is dropped and supplied into the welded pipe, the deposition surface of the powder is directly connected to the winding of the welded pipe from the conduit opening at the rear of the welded pipe. The feed rate of the welded tube is controlled synchronously with the amount of powder supplied so that it is always maintained within the predetermined control range up to the starting point, while the temperature of the weld zone and the welded tube speed are detected. Based on the detection signal, the power input to the welding power source is controlled via the welding temperature control circuit so that the welding temperature always provides a healthy weld, so when filling the welding pipe Z with powder, Even if the feed speed of the welded pipe changes, the powder will not be adversely affected by the heat of welding, and the welded area will not be adversely affected by the adhesion of powder, allowing for sound welding. Therefore, it is possible to obtain a product of good quality and to perform manufacturing with good production efficiency.

[Brief explanation of the drawing]

The drawings are a) showing an embodiment of the present invention, in which Fig. 1 is a schematic side view showing an apparatus for manufacturing a powder-filled welded tubular body, and Fig. 2 is an enlarged view of a part of the manufacturing apparatus. Fig. 3 is an enlarged partial longitudinal side view showing a powder accumulation surface level detection control device in the manufacturing equipment, and Figs. FIG. 2 is a cross-sectional view showing the sequence in which the powder-filled welded tubular body is manufactured, and corresponds to the position A-A-G-C, 151 in FIG. 1; In the figure, 1 is a metal strip, 2 is a strip feeding spool, and 6
is an electric motor, 4 is a tubular body take-up spool, 5 is a welding tool, 6 is a powder supply conduit, 7 is a welding pipe, 8 is a powder upper limit position detector, 9 is a powder lower limit position detector, 10 is an electric motor rotational speed control device; 13 to 16; first to fourth forming rolls; 1;
8 is pressure roll 1, 19'i powder 5.20
11''・214 powder 47 (-dar), 24 is a detector for monitoring the powder accumulation surface, 25 is a detection signal processing circuit, 26 is an output processing circuit, 27 is a powder display unit, and 28 is a powder level recorder. , 29 is a motor control circuit, 30 is a tilt support table, 35 is a hydraulic solinoda for adjusting the tilt of the support table, 64 is a powder-filled welded tubular body, 65 is a powder deposition surface, 66 is a welded pipe speed detector, 6
7 is a welding temperature control circuit, and 58 is a welding τ temperature detector. Figure 8 Figure 9 Figure 10

Claims (1)

[Claims] A welded pipe 7 is formed by sequentially bending a long metal strip 1 in the width direction and sequentially welding the bent edges, and a pipe for supplying powder from the opening of the unwelded bent portion of the metal strip 1. In a method of manufacturing a coiled powder-filled welded tube by inserting a conduit 6, supplying the powder into the welded tube 7 through the conduit 6, and then rolling it up, the welded tube is dropped. When powder is supplied falling into a welded pipe at an angle greater than the angle of repose of the powder, a control method is established in which the deposition surface of the powder is from the conduit opening behind the weld to the start point of winding the welded pipe. The welding tube feed rate is synchronously controlled according to the powder supply amount so that it is always maintained within the range.The welding zone temperature and welding tube speed are also detected, and the detection signal is used to control the welding temperature control circuit. A method for manufacturing a powder-filled welded pipe, characterized by controlling the power input of a welding power source so that the welding temperature always provides a healthy welded part.