JP2002001529A - Column joint welding method for extra thick h-shape steel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electroslag welding method for an extra thick H-shape steel capable of improving welding efficiency and reducing weld defects such as incomplete fusion of a weld part in column joint welding for an extra thick H-shape steel having a flange thickness of 30 mm or more. SOLUTION: In this column joint welding method for an extra thick H-shape steel, a groove part is provided on a flange part so that a flange line is tilted at an angle of 30-60 deg. to a flange width direction, and either a water cooling copper plate or a copper plate or both of them is/are mounted inside or outside the flange so as to surround the groove part. As a result, leakage of molten metal during welding is prevented, an angle of welding wire to the groove line is adjusted at (20-α/3)-20 deg. then upward welding is continuously conducted by the electroslag welding method along the groove line.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for butt welding H-beams used in steel columns of building structures. More specifically, the present invention relates to a welding method for an extremely thick H-section steel having a flange thickness of 30 mm or more.

[0002]

2. Description of the Related Art In recent years, with the increase in the size and height of building structures, the development of manufacturing techniques for H-section steels used in steel columns of steel structures has progressed. A thick H-section steel with good weldability can be manufactured relatively inexpensively. On the other hand, when such an ultra-thick H-section steel is applied to a steel structure as a column material or the like, and joining is performed at a construction site, the joining technique of the ultra-thick H-section steel is problematic from the viewpoint of joint characteristics and workability. It has become.

[0003] Conventionally, as a method of using a relatively thin H-section steel as a column material and joining it at a construction site, the workability and
From the viewpoint of reliability, bolt joining has been the mainstream. However, in the case of an H-section steel having an extremely thick flange thickness of 30 mm or more, cross-sectional loss of a joint portion due to a bolt hole becomes a problem in bolt joining, and therefore, as shown in FIG. 2a, 2b) are joined by bolts 5,
In many cases, a hybrid joint is used to join the flanges (1a, 1b, 1c, 1d) by welding, or all the webs and flanges of the two materials to be joined are joined by welding.

[0004] In conventional welding of a column joint of H-section steel, welding is performed in a horizontal welding position, and in order to prevent dripping or running out of the weld metal at that time, multi-layer welding 30 with a relatively low current and a low welding amount is used. Is carried out, for example, a thickness of 80 m
For welding a very thick steel material having a thickness of m, the number of welding passes was as large as 70 and the welding efficiency was extremely reduced.

[0005] In conventional column joint welding of H-section steel,
Due to the multi-pass welding, fusion defect defect 31 is likely to occur between the laminations of each welding pass, and when multi-pass welding is performed with a very large number of passes such as extremely thick steel materials, a weld defect may occur. It is extremely high and it is difficult to maintain the quality of the weld.

That is, when welding an extremely thick H-section steel having a flange thickness of 30 mm or more by the conventional welding method, there is a problem in that the welding efficiency (welding time) and the joint quality (defective fusion defect) are deteriorated. Was.

[0007] As a method for improving the welding efficiency of the conventional multi-layer welding in the horizontal position, for example, Japanese Patent Application Laid-Open No.
An automatic welding method for a thick plate such as a blast furnace steel bar disclosed in Japanese Patent No. 281428 is known. In this welding method, the torch inclination angle is controlled in the groove depth direction of the groove or the groove of the K-shaped groove and gradually moved in the welding progress direction while weaving to finish one layer at a time from the lower surface of the groove. However, there is a limit to the improvement of welding efficiency especially when the groove width is narrow due to the limitation of the welding torch inclination angle due to the groove width. Further, this welding method requires an expensive device for controlling the weaving of a special torch, and is hardly practically used.

On the other hand, as a welding method in a vertical position, the welding efficiency of which is superior to that of the horizontal position welding method described above,
For example, diaphragm welding of a box column by an electroslag welding method disclosed in JP-A-61-78577 is generally known.

In this electroslag welding method, for example,
As shown in FIG. 11, the groove portion is covered with a backing metal 7 (or a water-cooled copper plate) to prevent the molten metal 13 and the molten slag 12 from flowing out, while abutting portions (opening portions) of steel plates 32 to be joined. Welding is performed efficiently in one pass with a high welding current of about 500 amperes in the vertical direction in the upright position, and the convection 14 to the upper steel plate and the retained heat of molten metal and molten slag are also used. Therefore, even when the groove portion is narrow, a good penetration depth can be secured, and high quality of the welded portion can be achieved. In addition, by supplying the welding wire 11 to the electrode nozzle 16 and oscillating the electrode nozzle 16 in the thickness direction or increasing the number of electrodes, it is possible to perform one-pass welding of an extremely thick steel plate having a thickness of about 100 mm. Become.

[0010] However, the conventional electroslag welding method is intended for vertical joint welding in the vertical position of a standing steel plate, and in the horizontal position for welding a column joint of an H-section steel in a horizontal position. There is no application example at all.

[0011]

DISCLOSURE OF THE INVENTION The present invention relates to a pole welding method which can improve welding efficiency and reduce welding defects such as poor fusion of welded portions in column joint welding of extremely thick H-section steel having a flange thickness of 30 mm or more. An object of the present invention is to provide an electroslag welding method for a thick H-section steel.

[0012]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and the gist thereof is as follows.

(1) In a method of welding a column joint made of an extremely thick H-section steel, a groove is provided on a flange portion so that a groove line forms an oblique angle with respect to the flange width direction, and the groove is surrounded. By installing one or both of a water-cooled copper plate and a steel plate on the inside and outside of the flange, the outflow of the molten metal during welding is prevented, and the electroslag welding method is used along the groove line. A column joint welding method for an ultra-thick H-section steel, characterized by selectively upward welding.

(2) The oblique angle of the groove with respect to the flange width direction is 30 to 60 deg. And the angle of the welding wire with respect to the groove line is (20-α / 3) to 20 de.
g. The extremely thick H according to the above (1),
Column joint welding method for section steel.

(3) The angle of the welding wire with respect to the groove line is adjusted by providing a welding tip such that the axis is inclined with respect to the axis of the electrode nozzle. ) Or (2), the method of joint welding a very thick H-section steel.

(4) Adjusting the angle of the welding wire with respect to the groove by supplying the welding wire with a bending habit in advance and supplying the welding wire to an electrode nozzle having a vertically long groove cross-sectional shape. The column joint welding method for an ultra-thick H-section steel according to the above (1) or (2), characterized in that:

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.

The electroslag welding method is an excellent welding method from the viewpoint of improving efficiency and reducing defects at the time of construction. However, since it is intended for vertical joint welding in the standing position of a standing steel plate, the extremely thick H The welding method cannot be directly applied to the horizontal groove of the column joint of the section steel.

Therefore, instead of providing the groove in the welding of the column joint in the horizontal direction as in the prior art, the inventors of the present invention have proposed:
By providing the groove at an oblique angle, the application of electroslag welding of an extremely thick H-section steel was eagerly studied.

FIGS. 1 and 5 are schematic views showing a method of joint welding a very thick H-section steel using the electroslag welding method of the present invention. In addition, in FIG. 1, the web (2a, 2b) of the H-shaped steel which is two to-be-joined materials is used using the splice plate 4,
Although the bolt connection is performed by the bolt 5, it is also possible to perform welding connection.

In the present invention, as shown in FIG. 1, the grooves (3a, 3b) of the flanges (1a, 1b, 1c, 1d) of the H-section steel to be joined are connected to the horizontal lines (h, h '). A backing metal 7 on the inside of the flange (web side) and a water-cooled copper plate 8 on the outside of the flange so as to cover the groove so that molten metal does not flow out during welding. Each is installed, and as shown in FIG. 5, the groove is welded by a welding wire 11 while moving upward along a groove line provided with a bevel from below.

According to the experiments by the inventors, it has been found that the quality of the welded portion is greatly affected by the groove line angle α, the angle of the welding wire, and the relative angle of the welding wire to the groove line.

FIG. 4 shows the groove line angle α for a very thick steel plate having a thickness of 70 mm and the angle β of the welding wire with respect to the groove line.
4 shows the state of occurrence of a welding defect in a welded part when the value is changed.

FIG. 4 shows that when the angle β of the welding wire with respect to the groove line is 0, that is, when the axis of the welding wire is parallel to the groove line, the welding defects in the weld tend to increase as the groove angle α decreases. And the groove line angle α is 60 deg. In the above, no welding defect occurs in the welded portion, but the groove angle is 60 deg. As shown in FIG. 2, poor welding of the weld metal 9 on the lower side of the groove into the steel plate, that is, welding defect of poor fusion 10 of the lower steel plate occurred.

The mechanism by which welding defects such as poor penetration (poor fusion) 10 occur in the weld metal 9 below the groove is considered as follows. As shown in FIG.
In the electroslag welding of the flanges 1a and 1c of the H-section steel using No. 1, unlike ordinary arc welding, the convection of the molten slag 12 above the molten metal 13 controls the melting phenomenon, and When welding with
The convection 14 of the molten slag to the steel plate on the top of the groove increases, and the convection 15 of the molten slag on the steel plate on the bottom of the groove tends to decrease. It is thought that it became shallow. The tendency of the convection 14 of the molten slag to the steel plate above the groove to increase, and conversely, the convection 15 of the molten slag to the steel plate below the groove to decrease, is due to the increase in the groove angle α and the It is thought that it becomes larger as the angle β of the welding wire decreases.

From the experiments shown in FIG. 4 and the like, welding defects with poor penetration can be suppressed by decreasing the groove angle α and increasing the angle β of the welding wire with respect to the groove, and β ≧ 20−
It has been found that by controlling the angle β of the welding wire with respect to the groove line so as to satisfy α / 3, welding defects with poor penetration can be suppressed. However, the groove angle is 30 deg. In the following, it has been found that even if the angle β of the welding wire with respect to the groove line is controlled, the defect of poor penetration at the weld cannot be prevented. If the angle β of the welding wire with respect to the groove line is too large, the possibility that the welding wire contacts the groove wall surface increases, and the angle β
Is 20 deg. When it exceeded, angle adjustment was impossible.

Further, as shown in FIG. 4, as the groove line angle α is larger, welding defects are less likely to occur, but as the groove line angle α becomes larger, the length of the welding line becomes longer and the welding efficiency is reduced. Therefore, in practice, the upper limit of the groove line angle α is 6
0 deg. It is desirable to be about.

For the above reasons, in the present invention, the welding groove angle α is set to 30 to 60 in order to secure the welding workability and the welding efficiency and to prevent the defect of poor penetration at the welded portion.
deg. And the angle β of the welding wire with respect to the groove line is (20−α / 3) to 20 deg. It is necessary to

In the present invention, the method of controlling the angle β of the welding wire with respect to the groove line is, for example, as shown in FIG.
As shown in FIG. 2, the angle can be obtained by making the angle β of the axis of the welding tip 17 at the tip of the electrode nozzle 16 with respect to the axis of the welding wire 11.

However, in this method, if the welding wire 11 is to be kept at a predetermined protrusion length L, the space 18 between the wall surface of the groove 1c and the electrode nozzle 16 becomes narrow, and the electrode nozzle 1
6 easily comes into contact with the wall surface of the groove 1c.
Needs to be large. When the groove interval is increased, the welding efficiency is reduced, and the toughness of the welded portion is reduced due to an increase in welding heat input. Therefore, when this method is used, it is desirable to adjust the protrusion length L and the groove gap g so as not to degrade the quality of the welded portion based on the welding conditions such as the plate thickness. In FIG. 5, 13 is a molten metal, and 1a and 1c are H-section steel flanges.

As another method of controlling the angle β of the welding wire in the present invention, as shown in FIG. 6, a bending habit imparting roller 19 and a guide are previously applied to the welding wire 11 supplied to the electrode nozzle 16 and the welding tip 17. There is a method of giving a bending habit by the roller 20. The method of giving a bending habit to the welding wire 11 with the bending habit imparting roller 19 is also used in a normal arc welding method,
The groove shape for passing the welding wire in the conventional electrode nozzle 16 was circular. When the electrode nozzle 16 having such a circular groove shape is used in electroslag welding, the electrode nozzle 16 is 500 to 100 in electroslag welding.
Since the welding wire is required to be longer than 0 mm as compared to arc welding, the welding wire is twisted when passing through the electrode nozzle 16, and the direction of the bending habit of the welding wire after passing through the welding tip 17 is likely to vary.

Therefore, in the present invention, the shape of the cross section 21 of the groove 22 for passing the welding wire of the electrode nozzle 16 is made to be vertically long, and the direction of the bending habit of the welding wire and the electrode nozzle 16
By supplying the welding wire 11 to the electrode nozzle 16 so as to match the longitudinal direction of the welding wire passage groove 22 of the welding wire, the variation in the bending habit direction of the welding wire after passing through the welding tip 17 is prevented, and With no contact between the nozzle 16 and the groove wall surface, the angle β of the tip of the welding wire 11 with respect to the axis of the welding tip 17 can be controlled.

According to the experiments by the inventors, the method of imparting a bending habit to such a welding wire has enabled narrow groove welding with a groove interval g of about 15 to 20 mm.

[0034]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which column welding of an H-section steel is performed by using the present welding method will be described below with reference to FIGS.

Flange thickness 70 mm, flange width 500 m
m, web thickness 30 mm, web width 1000 mm,
The webs of extremely thick H-section steel having a steel type of SM490 were joined by bolts, and the flanges were joined by butt joining by electroslag welding. The groove angle of the flange is 30 deg. And

Hereinafter, the welding method will be described in detail.

(Welding preparation step) (1) The end face of the H-section steel is cut by gas cutting. The web is cut in a cross-sectional direction perpendicular to the longitudinal direction of the H-section steel, and both flanges 1a, 1b, 1e, of the webs 2b, 2c of the H-section steel are cut.
1f is 30 deg. The groove was cut so as to become. At this time, the direction of the groove line angle was set as shown in FIGS. 7A, 3B, 3C, and 3D from the viewpoints of the following welding deformation and prevention of fracture due to brittle cracks in the welded portion.

Regarding welding deformation after welding, in electroslag welding, rotational deformation due to contraction of the welding end portion (upper groove) is likely to occur. Therefore, the groove angle is set such that the groove directions of the groove lines 3a, 3c, 3b, and 3d in the same flange intersect with each other so that rotational deformation does not accumulate at the time of longitudinal joint welding of the H-shaped steel columns. Provided. In order to prevent the propagation of the brittle crack and prevent the brittle fracture from becoming large, it is effective means to shift the welded portion, which is the starting point of the crack, from the same cross section. Therefore, the groove lines 3a and 3b and the groove lines 3c and 3d of the flanges facing each other in the joint portion of the H-shaped steel column are crossed with each other.

(2) The webs 2b and 2c of the H-section steel are drilled for bolt joining.

(3) As shown in the sectional view of the flange joint portion in FIG. 8, the backing metal 7 is attached inside the flange 1a (on the web side). In the case of electroslag welding, the backing metal 7 is attached particularly at the lower side of the groove at the time of welding.
And the corners of the H-shaped steel flange 1a and the backing metal 7 on the lower side of the groove are subjected to inner surface temporary welding 23 in advance at the factory, and the H The outer surface was temporarily welded 24 to the flange 1c of the H-section steel on the upper side of the groove when the section steel was built.

When the steel backing metal 7 was installed on the front side of the flange instead of the water-cooled copper plate 8, the inner surface was temporarily fixed.

(4) An H-section steel is erected, and the web is bolted and the backing metal and the upper flange are temporarily attached.

(Welding process) (5) As shown in the schematic view of the flange joint portion in FIG. 9, the tab plate 25 and the groove on the flange outer surface are provided at the welding start portion at the groove portion on the inner side surface (web side surface) of the flange. The tab plate 26 is attached to the welding end part (end part) of the part.

(6) The welding device is set at a predetermined position on the side of the welding end. As shown in FIG. 9, the welding device includes a welding power source 27, a welding wire feeder 28, a wire bending habit imparting roller 19, an electrode nozzle 16, a welding tip 17,
It is composed of an electrode nozzle lifting mechanism 29 and the like. The adjustment of the angle and the groove width direction of the welding electrode (16 + 17) was manually performed, and the elevation of the welding electrode (16 + 17) and the swing in the plate thickness direction were performed by automatic control.

(7) A water-cooled copper plate is placed on the groove on the front side of the flange.

(8) The flux is supplied and welding is started. The welding conditions were a welding current of 450 amps and a welding voltage of 5
Two volts and a slag bath depth of about 25 mm were used. The welding wire inclination angle was 15 deg. With respect to the angle of the groove line using the welding wire bending habit imparting mechanism of the present invention. The test was carried out with a tilt in the vertical direction.

(9) At the end of welding, the welding voltage was controlled to be slightly lower so that care was taken not to cause crater cracks.

(10) The operations of (4) to (9) are repeated, and the other flange is welded.

Table 1 shows a comparative example using the conventional multi-layered horizontal welding method and an example of the invention using the electroslag welding method with a bevel groove according to the present invention. In the present invention,
In order to confirm the effect of reducing the groove width by controlling the bending habit of the welding wire, the case where the groove width was 10 mm and 30 mm was evaluated. Regarding the welding time in the table, the welding time of one side flange is shown. Compared with the conventional multi-layer welding method of the comparative example, when the electros slag welding method of the invention example is used, the welding time is significantly reduced. It has become possible. In addition, in the invention examples, the effect of shortening the welding time by reducing the groove width was also confirmed.

Regarding the welding quality, as a result of performing a radiation transmission test and an ultrasonic flaw detection test on the welded portion, defective fusion was generated in the conventional method of the comparative example, while defect-freeness could be achieved in the example of the present invention. Was.

Regarding the impact absorption energy (0 ° C.) obtained by the Charpy test of the welded portion, the absorption energy tends to be lower in the electroslag welding of the invention example than in the multi-layer welding of the comparative example, and there is a groove. Although the absorbed energy tends to be further reduced as the interval is wider, all of them satisfy 27 J or more, which is a standard of a building structure.

Table 2 shows the invention examples in which the groove line angle α and the welding wire angle β with respect to the groove line are within the range of the present invention when welding is performed using the electroslag welding method with a bevel groove. The results, such as welding time and welding quality, of the comparative examples outside the range are shown. The welding conditions such as the used test piece, welding current value, and voltage value were the same as those in the above-described embodiment. Also,
The groove interval was 20 mm.

In Comparative Example 1, the groove line angle α was 60 deg.
Comparative Example 5
Has a groove angle α of 30 deg. Because of the smaller size, a defective defect occurred at the weld. In Comparative Example 4, the angle β of the welding wire with respect to the groove line was 25 deg. Therefore, the welding tip contacted the groove wall and interrupted the welding.

In Comparative Examples 2 and 3, the angle β of the welding wire with respect to the groove line was (20−α / 3) deg. Lower than that of the welds, the welds had poor penetration defects.

On the other hand, both the groove line angle α and the angle β of the welding wire with respect to the groove line are Examples 1 to 3 of the present invention.
In No. 5, good weld quality was obtained with no weld penetration defect, and both welding workability and efficiency were good.

[0056]

[Table 1]

[0057]

[Table 2]

[0058]

As described above, according to the present invention, in beam joint welding of an extremely thick H-section steel having a flange thickness of 30 mm or more, good welding workability and efficiency even with a narrow groove and no welding defects. One-pass electrogas arc welding with excellent weld quality can achieve extremely high efficiency welding compared to conventional multi-layer arc welding.

Therefore, the present invention greatly contributes to shortening the construction period and cost of on-site welding of building steel frames and the like.

[Brief description of the drawings]

FIG. 1 is a schematic view of an ultra-thick H-section steel column joint weld of the present invention.

FIG. 2 is a view showing a cross-sectional shape of a weld metal at the time of poor penetration when an oblique groove is welded by an electroslag welding method.

FIG. 3 is a view showing an image of a welding slag convection phenomenon at a welded portion when a bevel groove is welded by an electroslag welding method.

FIG. 4 is a diagram showing a state of occurrence of welding defects at a welded portion when a groove line angle α and an angle β of a welding wire with respect to a groove line are changed.

FIG. 5 is a cross-sectional view showing an embodiment for adjusting the angle of a welding wire according to the present invention, and showing an arrangement of a groove portion and a welding tip.

FIG. 6 is a view showing an embodiment for adjusting a welding wire angle according to the present invention, and is a view schematically showing a welding wire bending habit imparting mechanism.

FIG. 7 is a diagram illustrating a groove position of a joint portion of an extremely thick H-shaped steel column for describing an example of the present invention.

FIG. 8 is a flange cross-sectional view illustrating a temporary attachment state of a backing metal for describing an example of the present invention.

FIG. 9 is a view showing a welding condition of a column joint of an extremely thick H-section steel for explaining an example of the present invention.

FIG. 10 is a view showing a conventional column joint welding method for an extremely thick H-section steel by multi-layer horizontal welding.

FIG. 11 is a diagram showing a conventional vertical position joint welding method for a vertical steel plate by electroslag welding.

[Explanation of symbols]

1a, 1b, 1c, 1d, 1e, 1f H-section steel flange 2a, 2b, 2c H-section steel web 3a, 3b, 3c, 3d Flange groove 4 Splice plate 5 Bolt 6 Scallop 7 Backing metal 8 Water-cooled copper plate 9 Weld metal 10 Poor fusion of lower steel plate 11 Welding wire 12 Molten slag 13 Molten metal 14 Convection to upper steel plate 15 Convection to lower steel plate 16 Electrode nozzle 17 Welding tip 18 Distance between electrode nozzle and groove wall 19 Welding wire bending habit imparting roller 20 Roller guide 21 Cross section of electrode nozzle 22 Welding wire passage groove 23 Groove inner surface temporary welding 24 Groove outer surface temporary welding 25 Tab plate at welding start part 26 Tab plate at welding end part 27 Welding Power supply 28 Welding wire feeder 29 Electrode nozzle lifting mechanism 30 Multi-layer welding 31 Defective fusion defect 32 Standing plate A Welded section L Length of welding wire protruding a, a 'Welded section observation position b, b' Electrode nozzle cross-section observation position g Groove interval h, h 'Horizontal line α Groove for horizontal line Angle β Difference between groove angle and welding wire angle

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yoshihiro Inmaki 20-1 Shintomi, Futtsu-shi F-term in the Technology Development Division, Nippon Steel Corporation 2E125 AA04 AB01 AC15 AG03 AG12 AG56 BA55 BB02 BB22 BD01 BE02 BE05 CA05 CA14 CA90 EA01 EA33 EB12 4E081 YB05 YX02 YX03 YX07 YX17 YY12

Claims (4)

[Claims] In a method for welding a column joint of an extremely thick H-section steel, a groove is provided on a flange so that a groove is inclined at an angle to a width direction of the flange, and the groove is surrounded. By installing one or both of a water-cooled copper plate and a steel plate on the inside and outside of the flange to prevent outflow of molten metal during welding, continuous electroslag welding along the gap line -Joint welding of extra-thick H-section steel, characterized in that it is welded upward. 2. An oblique angle of the groove with respect to the flange width direction is 30 to 60 deg. And the angle of the welding wire with respect to the groove line is (20-α / 3) to 20 deg. The method according to claim 1, wherein the beam is welded to an extremely thick H-section steel. 3. The angle of the welding wire with respect to the groove line is adjusted by providing a welding tip so that the axis is inclined with respect to the axis of the electrode nozzle. 3. The method for welding a column-thickness H-section steel beam according to item 2. 4. A method for adjusting the angle of the welding wire with respect to the groove line by supplying a bending habit to the welding wire in advance and supplying the welding wire to an electrode nozzle having a vertically long groove cross-sectional shape. Claim 1.
Or the column joint welding method for an extremely thick H-section steel according to item 2.