JPH0615111B2 - Bead removal method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a high-frequency resistance welding method for producing a welded section steel having a right-angled corner portion such as a welded H-section steel between a web and a flange. The present invention relates to a removing method for removing generated welding beads.

[Conventional technology]

Conventionally, the following method is generally known as a method for removing the welding beads of this type.

Make a notch in the bead with an idle disc cutter and push the bead with the notch with a roll. And after that, as a finish, the bead portion that was pressed and broken is removed with a brush. (Japanese Patent Laid-Open No. 64-1009013
(Gazette) Immediately after welding and forming to a shaped steel, oxygen is blown to the heated welding bead. At this time, the bead portion is ablated by the oxidation reaction and oxygen pressure generated in the bead. (Refer to Japanese Utility Model Laid-Open No. 54-10926) While the welding bead generated by the welding of the web and the flange is in a red hot state, the bead portion is repaired and removed by crushing the bead in the red hot state with a roll. What to do. (See Japanese Laid-Open Patent Publication No. 56-62682) [Problems to be solved by the present invention] However, in such a conventional removing method, in the above-mentioned case, due to the structure of an idle disk cutter or the like which makes a cut in the bead portion, From a small-sized shaped steel (1
It is difficult to deal with (50H or less).

Also, due to changes in bead size and material strength, some parts cannot be completely broken. Further, due to the runout of the shaped steel, the blade breakage of the idle disk cutter occurs (even if the runout width is about 0.2 to 0.5 mm, the breakage occurs).

In this way, in the bead removal only by mechanical contact cutting such as an idle disk cutter, the number of replacement steps increases from the mechanical life such as the above-mentioned cutting edge breakage,
Maintenance work becomes troublesome.

In one case, the installation position of the oxygen blowing nozzle is limited to the position immediately after the apparatus for performing the welding forming on the shaped steel. This means that the slag generated during bead welding is scattered on the web support roll and the auxiliary equipment in the apparatus for welding and shaping the shaped steel, and affects the welding quality. In addition, roll entrainment may occur.

In the further case, the equipment, efficiency, etc. are good, but the pretreatment agent (chemical conversion treatment) remains due to entering the gap portion 18 (see FIG. 10) in the bead crushing portion 17 during the post-treatment electrodeposition coating. Will occur. This is
In the remaining portion of the pretreatment agent, coating failure will occur.

The present invention was devised in view of the above-mentioned circumstances, and its purpose is to remove beads regardless of the size of shaped steel and to perform maintenance for that purpose easily. Bead removal can be performed efficiently and reliably in a stable state without affecting the welding work for forming steel, and without being affected by the bead shape and the amount of heat of the bead, and prevent uneven coating. It is to provide a bead removal method that can be performed.

[Means for Solving the Problems]

According to the method of the present invention, a bead melting portion is provided in a section steel production line having a right-angled corner portion. Then, at the bead melting portion, the bead portion generated at the right-angled corner portion during the welding operation to the shaped steel is to be ablated and removed by gouging using a plasma torch. It also eliminates mechanical life and size restrictions so that it can respond to changes in bead size and material.

As this gouging process, there is known a technique of gouging a flat plate surface with plasma momentum, as disclosed in JP-A-58-81563. This describes the tilt angle between the vertical line from the member to be gouged and the plasma torch with respect to one direction (the gouging traveling direction) because it is a flat plate.

Therefore, this is different from the case where the bead portion generated at the right-angled corner portion is fused and removed by gouging as in the present invention. Therefore, in the gouging processing to the right-angled corner portion in the method of the present invention, the inclination angle between the vertical line from the member to be gouged and the plasma torch is set in two directions, that is, the gouging advancing direction and the direction orthogonal to the gouging advancing direction. Angle setting is required.

Further, at this inclination angle, it is 3 in JP-A-58-81563.
Although it is described in a wide range of 0 ° to 70 °, the gouging at a right angle corner becomes extremely poor in cutting property when it becomes 45 ° or more, and a corrugated gouging surface is obtained. Therefore, 40 to obtain a stable gouging surface. The best range is around 30 ° to 45 °.

As described above, conventionally, no technique has been established for performing gouging processing using a plasma torch at a right-angled corner portion.

Therefore, in the bead removing method of the present invention, each use condition of the plasma torch at the time of performing gouging processing is set as follows.

"Inclination angle of plasma torch" When gouging with plasma, if the torch is not tilted, the molten metal cannot be blown away, so the molten metal will flow back and fill the gouging location.

Further, at the right-angled corner portion, the plasma arc serves as a wall for both the web and the flange, and therefore it is necessary to make a large inclination in order to blow off the molten metal.

From these facts, as shown in FIG. 4, the angle θ ₁ between the flange 1a and the plasma torch 2 in the shaped steel 1 in the direction of gouging is set to 20 ° to 40 °, and the gouging proceeds as shown in FIG. The angle θ ₂ between the flange 1a and the plasma torch 2 in the direction perpendicular to the direction is 50 ° to 7 °.
Set at 0 °.

20 ° at the angle θ ₁ and 70 ° at the angle θ ₂ are
It is a value due to physical constraints.

"Swirl Flow Direction and Velocity of Plasma Arc Working Gas in Plasma Torch" As shown in FIG. 2, the swirl direction and flow velocity of the plasma arc working gas generated in the screw portion 3 in the plasma torch 2 are also the molten metal and the flash. Need to be set in order to reliably blow away.

Therefore, the swirl direction of the plasma arc working gas is
When the shaped steel 1 flows as shown in the drawing, the torch 2 on the front side of the drawing turns right and the torch (not shown) on the opposite side of the drawing turns left.

When the swirling flow direction of the plasma arc working gas is set to the flow direction of the shaped steel on the production line as described above, the molten metal is easily blown off, and the welded surface can be improved. And when they are respectively turned in the opposite directions, a molten metal pool or the like is formed and the abraded surface cannot be cleaned.

Also, the swirl velocity of the plasma arc working gas is
The screw angle θ (see FIG. 7) is reduced from 7.8 ° to 6 to 7 °, and the screw shape of the screw portion 3 is increased from two to one.

"Nozzle shape in plasma torch" If the nozzle diameter is small and the arc concentration is too strong, the arc shifts from the bead and the surrounding base material (shaped steel) moves due to the shaking of the arc and the shaking of the base material (shaped steel). It will be ablated. Therefore, by dispersing the energy density of the arc to some extent, it is possible to allow each of the above-mentioned fluctuations, and it is possible to carry out stable welding of the bead portion without cutting the base material (shaped steel). it can.

However, if the energy density is dispersed too much, the surrounding base material (shaped steel) will also be ablated, and the amount of electric power used will increase because of the dispersion.

From these facts, the shape of the nozzle 4 in the plasma torch 2 is such that the diameter D of the nozzle injection port is changed from the conventional 2.5φ to 3.0φ to 3.5φ and the nozzle injection port length L is changed as shown in FIG. Is formed from the conventional 6 mm to 8 mm to 10 mm. Then, the energy density of the arc is dispersed to some extent to cover the entire bead portion. Note that the diameter D of the nozzle injection port is 3.0φ to 3.5
φ has almost the same fusing performance.

“Distance between the plasma torch and the bead to be ablated” When the distance between the bead and the plasma torch changes due to a change in the bead shape, a subtle change occurs in the shape of the treated surface after the bead ablation treatment, resulting in a smooth surface. It disappears and uneven coating occurs on this surface.

Therefore, immediately before the weld forming portion on the shaped steel, the bead portion generated in the weld forming portion is crushed by a roll before the bead melting portion where the bead is removed. As a result, the shape of the bead portion is made constant, and the distance between the plasma torch and the bead portion is made constant. At this time, as shown in FIG. 9, the distance L ₀ from the base material of the plasma torch 2 (the bead portion of the shaped steel 1) is 8 because
The most effective setting is about mm.

In order to prevent uneven coating, the surface of the bead-melting section is crushed with a roll after the slag removing section, etc., to smooth the surface of the bead-melting processing. .

"Air blow" During bead cutting with a plasma torch, if a flash scatters between the base material (shaped steel) and the torch, a short circuit will occur and the base material (shaped steel) will be flawed. In addition, the blown-out flash accumulates on the base material (shaped steel) and the torch, causing a short circuit.

Therefore, as shown in FIG. 2, the air blow nozzle 5 is attached immediately after the installation position of the torch 2. And the air pressure is 2-3 kg / so that the direction of the plasma arc does not change.
cm ² Further, the injection diameter of the air blow nozzle 5 is set to 6
φ to 8φ.

〔Example〕

Hereinafter, the bead removing method of the present invention will be described with reference to an example in which the bead removing method is performed at the time of manufacturing a welded H-section steel. (See FIGS. 1 to 9) In order to remove the bead based on the method of the present invention, the welding H
The bead removing device 6 (see FIG. 1) arranged on the production line for the shaped steel 1 is provided immediately after the high frequency resistance welded portion 7 forming the welded H-shaped steel, and is used for welding the shaped steel. A bead crushing portion 10 composed of a roll 9 for crushing the bead portion 8 generated at the time of work, a bead melting portion 11 which is provided at a certain distance from the high frequency resistance welding portion 7, and melts the bead portion 8, and this bead. The slag removing unit 13 including a brush 12 installed in the latter stage of the melting unit 11 and a crushing unit 14 including a roll 9 that crushes the bead-treated surface of the bead melting unit 11 are provided. Here, reference numeral 15 is a web support roll, and reference numeral 16 is a flange support roll.

And the plasma torch 2 of the bead melting part 11 here
(See FIG. 2), the working gas is air, and the pressure is 5 kg / cm ² . Further, the injection port diameter D of the nozzle 4 is set to 3.0.
Set φ to 8 mm for the injection port length L. The nozzle distance L ₀ from the bead portion 8 of the plasma torch 2 is 8 mm. Further, the flange 1a in the shaped steel 1 in the gouging traveling direction
The angle θ ₁ between the plasma torch 2 and the plasma torch 2 is 35 °, and the angle θ ₂ between the flange 1a and the plasma torch 2 in the direction intersecting the gouging traveling direction at right angles is 55 °.

When the bead removing device 6 having the above-described structure and carrying out the bead removing method of the present invention is used to remove the bead portion 8 generated during the welding formation of the welded H-section steel 1, the bead portion 8 does not come into contact with the bead portion 8. Because of this, the tool life is longer than that of conventional mechanical cutting, and even small sizes (80H) can be handled. In addition, the size and material of the bead portion 8 can be freely adjusted by changing the current value, and the material (SUS,
etc.) can be handled by changing the plasma working gas (air to oxygen or argon).

Further, in order to stabilize the welded surface of the bead portion 8 processed by the plasma torch 2, the bead head is pressed by the roll 9 of the bead crushing portion 10 in a region where the bead portion 8 is heated, and the bead portion 8 and the plasma are By making the distance from the torch 2 constant, the welded surface of the bead portion 8 can be stabilized.

In addition, if the pressing force of the roll 9 in the heating area of the bead portion is pressed even more strongly, the bead fusing depth will result in fusing of thin ones of 1.5 mm to 0.5 mm. Power consumption can be saved.

In addition, in order to finish the beaded abraded surface treated with the plasma torch 2 into a smoother surface, after the abrading, the roll 9 of the crushed portion 14 is pressed to form a smoother abraded surface with a better appearance. You can At this time, the roll 9 is installed in the latter stage of the slag removing section so that it only contacts the bead section 8.

In this way, the work of removing the beads generated during welding of the welded H-section steel is performed.

In addition to the welded H-section steel of the above-described embodiment, the removal method of the present invention can be applied to removal of beads such as electric resistance welded pipe and T-section steel.

〔The invention's effect〕

According to the bead removing method of the present invention, since the bead can be removed in the cold region by positively melting it in the bead melting portion, the H-shaped steel is not limited to the removing work position. Bead removal work can be performed at a position distant from the position of the welded portion. Therefore, the oxidized slag generated and scattered during the bead removing operation does not affect the welded portion to the H-section steel, and the bead can be reliably removed.

Also, the bead is not removed (welded) near the position of the weld to the H-section steel as in the conventional removal device, but it is performed at a position farther than the value of the welded part to the H-section steel, so a welding quality control index. The shape of the bead can be sufficiently confirmed.

Furthermore, bead removal can be performed regardless of the size of the shaped steel, and maintenance for that is also easy.Bead removal can be performed efficiently and reliably in a stable state without being affected by the bead shape and bead heat quantity, and uneven coating occurs. You can avoid it.

[Brief description of drawings]

FIG. 1 is a schematic view showing a bead removing device for carrying out the bead removing method of the present invention, FIG. 2 is an enlarged detailed view of part A of FIG. 1, and FIG. 3 is a view taken along the line BB of FIG. 4 and 5 are schematic views showing a torch angle, FIG. 6 is a schematic perspective view showing a working gas swirl state in the torch, and FIG. 7 is a schematic view showing a screw portion in the torch, and FIG. FIG. 9 is a schematic view showing the nozzle shape of the torch, FIG. 9 is a schematic view showing the distance between the torch and the fusing portion, and FIG. 10 is a schematic view showing a conventional bead removal state. 1 ... Section steel, 1a ... Flange, 1b ... Web, 2 ...
… Plasma torch, 3 …… Screw part, 4 …… Nozzle, 5…
... Air blow nozzle, 6 ... Bead removing device, 7 ...
High frequency resistance weld, 8 ... Bead, 9 ... Roll, 1
0 …… Bead crushing part, 11 …… Bead melting part, 12 ……
Brush, 13 ... Slag removing part, 14 ... Crushing part, 15
...... Web support roll, 16 …… Flange support roll,
17: bead crushing part, 18: gap part.

Claims (4)

[Claims] Claim: What is claimed is: 1. In a production line for a shaped steel having a right-angled corner, a bead melt generated by gouging using a plasma torch to remove a bead generated at the right-angled corner during welding work on the shaped steel. And a bead melting portion to remove the bead portion, wherein the angle between the flange and the plasma torch of the shaped steel in the gouging advancing direction is 20 ° to 40 °, and the gouging advancing direction. The angle between the flange and the plasma torch in a direction intersecting at a right angle is 50 ° to 70 °, the swirl flow direction of the plasma arc working gas is set to the flow direction of the shaped steel on the production line, and in the plasma torch The thread angle of the screw part is 6 to 7 °, the thread shape of the screw part is one thread, and the nozzle shape of the plasma torch is the nozzle injection port. Bead removal method comprising the in 3.0Fai～3.5Fai, also to the formation of the nozzle jet orifice length 8Mm～10mm. 2. The bead portion generated in the weld forming portion is crushed by a roll immediately before the weld forming portion to the shaped steel in the preceding stage of the bead melting portion for removing the bead so that the bead portion has a constant shape. The bead removing method according to claim 1, wherein the distance between the plasma torch and the bead portion is constant. 3. The bead removing method according to claim 1, wherein the welded surface is crushed by a roll at the latter stage of the bead melting section and at the latter stage of the slag removing section. 4. Immediately after the installation position of the plasma torch, the air pressure is set to ² to 3 kg / cm ² and an air nozzle having a nozzle injection port diameter of 6φ to 8φ is attached to blow the flash from the plasma torch. The bead removal method according to claim 1, which is characterized in that.