JPH08281436A - Two-electrode horizontal fillet welding submerged arc welding method for t-joint - Google Patents

Abstract

PURPOSE: To provide a two-electrode horizontal fillet welding submerged arc welding method of a T-joint to manufacture a welded wide flange shape with excellent efficiency by achieving the fillet welding under the prescribed welding conditions with a web in the horizontal position. CONSTITUTION: In a single layer fillet welding of a T-joint where a web is a thick steel prattle, a web 1 is in the horizontal position, and the fillet welding is achieved under the conditions where the diameter of L-pole wire: 3.2-6.4mm, the diameter of T-pole wire: 3.2-7.0mm, the ratio of the L-pole current to the T-pole current: 0.6-1.0, the voltage of L-pole: VL<=45V, the voltage of T-pole: VT<=50V, the angle of tiltation (a) of l,pole electrode: 3-30 deg., the angle of tiltation (b) of T-pole: 3-35 deg., the angle (c) of L-pole electrode: -10 to +10 deg., the angle (d) of tiltation of T-pole electrode: 0-30 deg., the distance between L-pole and T-pole: 10-120mm, the shortest distance between the L-pole and the flange: 0-10mm, and the shortest distance between the T-pole and the flange: 1-13mm. The web 1 is the thick steel plate exceeding 16mm and up to 32mm in thickness, and the fillet welding is achieved by the partial penetration method without groove.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for performing fillet welding of a T-joint of a thick steel plate in a horizontal position with high efficiency in the production of welded H-section steel and the like.

[0002]

2. Description of the Related Art H-section steel is produced by rolling H produced by hot rolling.
Welding H manufactured by assembling and welding shaped steel and thick steel plate
There is shaped steel. The latter is also referred to as a built H, and has the advantage that the dimensions such as wall thickness and width can be arbitrarily selected, and in many cases welded H-section steel is adopted for large dimensions such as for high-rise buildings.

In the production of welded H-section steel, downward fillet welding by a two-electrode latent arc welding method is usually adopted. This welding method is very common for fillet welding of T joints. The following are examples of horizontal fillet welding of thin steel sheets. The invention described in Japanese Examined Patent Publication No. 52-40299 relates to a welding method that does not cause welding defects such as pits and blow holes in fillet welding of steel sheets coated with a coating that is harmful to welding such as undercoating. Although not directly related to the present invention, in the publication, as an explanation of the prior art, a wire having a diameter of 3.2 mm or more is used.
As shown in (a), the inclination angle of the leading electrode (hereinafter referred to as the L pole when abbreviated) 4L is 40 to 60 ° with respect to the horizontal,
As shown in (b), it is described that a multilayer electrode buildup having an approximately isosceles triangular shape is performed with an inclination angle of a trailing electrode (hereinafter referred to as a T pole when abbreviated) 4T is approximately 35 to 55 °.

Further, in Japanese Laid-Open Patent Publication No. 57-68268, for example, in fillet welding between a tank side plate and an annular plate, in order to make the toe shape of the welded portion more gentle, And the side plate, and the relationship between the shortest distance between the trailing electrode and the side plate is defined, and welding is performed in one pool as shown in FIG. 5 with the inclination angle of the trailing electrode set to 60 to 90 °.

In the case of the welded H-section steel, in the case of a comparatively thin size with a web thickness of 16 mm or less, the welding strength is increased by increasing the leg length of the welded portion rather than allowing the web and the flange to sufficiently melt each other. I have secured. Therefore, the leg length is equal to or more than the plate thickness on both the web side and the flange side, and as shown in FIG. FIG. 6 is a schematic view showing a welded portion, 1
Is a web, 2 is a flange, and 3 is a welded portion (welded metal).

On the other hand, in the case of a welded H-section steel having a web thickness of more than 16 mm, it is not enough to secure the strength by overlaying, and partial penetration of 1/3 or more of the web thickness and flange side leg length of 1/3 or more, Alternatively, the strength must be ensured by the complete penetration and the leg length on the flange side of 1/4 or more. Therefore, when welding is performed in one pass, latent arc welding due to large heat input is required. However, when high heat input welding is performed in a horizontal position, undercut occurs on the flange side as shown in FIG. 7A and welding defects such as overlap occur on the web side as shown in FIG. 7B. As a solution to this, as shown in FIG. 6 above, the web side was groove-processed, and as shown in FIG. 8, the workpiece was tilted to perform the front welding downward, and the reverse was carried out to perform the back gouging and grinder finishing. After that, a method of welding the back side in a downward posture in a state where the object to be welded is tilted while being inverted has been generally used. FIG. 8 is a conceptual diagram showing this method, in which 1 is a web, 2 is a flange, and 4 is an electrode.

However, with this method, the work to be welded is reversed or moved for each work, and processes such as groove processing, gouging, and grinder finishing are indispensable, and it is difficult to improve the arc time rate as well as save labor. Met.
In recent years, with the increase in the size of structures represented by high-rise buildings, the size of steel materials used has also increased, and the plate thickness of H-section steel used as beams has also increased. Since the manufacturing time of H-section steel has been lengthened, increasing the efficiency of H-section steel production has become a new issue. Against this background, the present inventors have earnestly conducted research on a further fillet submerged arc welding method for T joints of thick steel plates, one end of which is disclosed in JP-A-5-57448 and JP-A-5-57448.
It is disclosed in Japanese Patent Publication No. 5-237659.

A high-efficiency fillet welding method for thick steel plates disclosed in Japanese Patent Laid-Open No. 5-57448 is as follows: As shown in FIG. Correspondingly, two-electrode latent arc welding with one pass on both sides is performed as complete or partial penetration. A firing type flux is used, the current ratio between the leading electrode and the trailing electrode is set to 0.65 to 1.00, the lead electrode is given a receding angle, and the trailing electrode is given an advancing angle. Further, the high-efficiency fillet welding method for thick steel plates described in Japanese Patent Laid-Open No. 5-237659 is to perform similar welding without providing a groove and limiting the composition of the flux and the wire.

According to these methods, the steps of gouging, grinder finishing, or groove processing, which have been conventionally required, can be omitted, so that the H-shaped steel production of thick steel plates can be dramatically improved as compared with the conventional methods. Became possible. However, also in this method, it is necessary to tilt the object to be welded by about 30 to 70 ° and perform the welding in a downward posture, as in the case of FIG. Therefore, there is no difference from the conventional method in that it is necessary to perform welding a total of four times in order to manufacture one H-section steel, and to perform the work of reversing the work piece every welding. Further, in this method, a positioner for inclining and rotating the object to be welded is essential, and without it, the work becomes more inefficient.

[0010]

SUMMARY OF THE INVENTION The present invention is intended to solve the above-mentioned problems, and specifically, during welding and assembling of thick H-section steel, welding defects such as undercuts and overlaps with the web held horizontally. By welding with a sufficient penetration depth and a leg length on the flange side, the aim is to produce a welded H-section steel with high efficiency by omitting the work of tilting the workpiece. By welding the two welding lines in the same direction in parallel, the welding H
The purpose is to significantly increase the efficiency of the production of shaped steel.

[0011]

According to the present invention as set forth in claim 1, in a single-layer fillet welding of a T joint in which a web material is a thick steel plate, the web is placed in a horizontal posture and the fillet welding is performed under the following welding conditions. This is a two-electrode horizontal fillet latent arc welding method for a T-joint, which is characterized in that it is performed. Note: L pole wire diameter: 3.2 to 6.4 mm, T pole wire diameter: 3.2 to 7.
0 mm, the ratio of L-pole current and the T-pole current _{(I T / I L):} 0.6~
1.0, L pole voltage _{(V L): V L ≦} 45V, T pole voltage _{(V T): V T ≦} 50V, L -pole electrode gradient (a): 3 to 30
°, T pole electrode inclination (b): 3 to 35 °, L pole electrode angle (c): −10 to + 10 °, T pole electrode angle (d): 0 to 30
°, distance between L pole and T pole (l): 10 to 120 mm, shortest distance between L pole and flange (e): 0 to 10 mm, shortest distance between T pole and flange (f): 1 to 13 mm.

The present invention according to claim 2 is that the web material is a thick steel plate having a plate thickness of more than 16 mm and up to 32 mm, and the fillet welding is fillet welding without groove processing by the partial penetration method. It is a two-electrode horizontal fillet latent arc welding method for the described T-joint. In the present invention according to claim 3, the web material is a thick steel plate having a plate thickness (t) of more than 16 mm and up to 60 mm, and fillet welding is performed on both sides of the web at a groove angle of 30 to 65 ° with respect to the plate thickness. 2. The T-joint according to claim 1, wherein the T-joint is fillet welding by a partial penetration method in which a groove groove having a depth of (1/5 to 1/3) t is provided.
Electrode horizontal fillet welding method.

According to a fourth aspect of the present invention, the web material is a thick steel sheet having a plate thickness (t) of more than 16 mm and 60 mm, and fillet welding is performed on both sides of the web at a groove angle of 30 to 65 °. 2. The T-joint according to claim 1, which is fillet welding by a complete penetration method in which a rectangular groove having a depth of (1/5 to 5/12) to the depth of t is provided.
Electrode horizontal fillet welding method. The present invention according to claim 5 is characterized in that the single-layer fillet welding according to any one of claims 1 to 4 is simultaneously performed in the T-joints at both ends of the web. This is a two-electrode horizontal fillet latent arc welding method.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The constitution and operation of the present invention will be described in detail below. The present inventors have earnestly conducted research on a method for efficiently performing fillet welding while maintaining a welded H-section steel, which is manufactured by assembling thick steel plates, in a horizontal posture, and as a result, obtained the following findings.

In order to obtain the penetration and the leg length in one pass, a large heat input welding of multiple electrodes is inevitably performed, the flange side undercuts due to the metal dripping, and the bead toe on the web side drips the metal. It is easy for overlap to occur. However, by appropriately selecting the electrode arrangement and welding conditions such as current value and voltage value, it may be possible to obtain a welding method that secures the necessary penetration and has a sufficient leg length and a smooth bead toe. all right.

In the case of partial penetration, a penetration depth of 1/3 or more of the web thickness is required, and in the case of complete penetration, a penetration depth of 1/2 or more of the web thickness is often required. The application of grooveless partial penetration welding is limited to the plate thickness of the web material up to 32 mm. If it exceeds 32 mm, the current value of the leading electrode inevitably increases in order to obtain a penetration depth of 1/3 or more of the web thickness, and the amount of welding becomes excessive, making it difficult to prevent welding bead overlap. .

When the plate thickness of the web material is 16 to 60 mm and partial penetration welding is performed, if the groove depth exceeds 1/3 and the depth becomes deeper, the welding amount increases and it is uneconomical. If it is shallower, there will be insufficient melting. In addition, if the groove angle is narrower than 30 °, insufficient melting or slag entrainment, cracking is likely to occur, and if it is wider than 65 °, not only is it uneconomical, but unmelted portion of the groove occurs, which is not preferable. .

Further, when the plate thickness of the web material is 16 to 60 mm and full penetration welding is performed, there is a risk of burn-through when the groove depth becomes deeper than 5/12, and it becomes shallower than 1/5. If this happens, insufficient penetration will occur, which is not preferable. Next, the welding conditions will be described. The function of the L pole is mainly to obtain a predetermined penetration depth, and the function of the T pole is to adjust the bead shape. In particular, in order to prevent undercuts and overlaps that occur in horizontal fillet welding, it is extremely important to select the T-pole electrode arrangement, current-voltage, and wire diameter. That is, it is preferable to select a small wire diameter for the L pole in order to obtain penetration, and to select a large wire diameter for the T pole in order to obtain a gentle bead shape without adding an excessive amount of welding.

If the diameter of the L pole wire is smaller than 3.2 mm, the bead width at the penetration tip becomes narrow and insufficient penetration, slag entrainment, blowholes and the like are likely to occur. If it is thicker than 6.4 mm, insufficient penetration will occur. When the amount of welding is excessive, overlap occurs and the bead has a convex shape. Therefore, it is necessary to adjust the amount of welding of the trailing electrode and adjust the bead shape. Therefore, the wire diameter of the T pole must be 3.2 to 7.0 mm. If the wire diameter is smaller than 3.2 mm, the welding amount increases and the above problems occur. If the wire diameter exceeds 7.0 mm, the arc spreads and undercut easily occurs on the flange side.

The ratio of the L pole current to the T pole current, I _T / I _L is
It should be 0.6-1.0. If it is less than 0.6, high temperature cracks are likely to occur in the weld metal formed by the preceding electrode, and welding defects such as poor fusion and slag inclusion also occur. In addition, the amount of welding is insufficient, resulting in insufficient throat thickness and undercut. When it is larger than 1.0, not only the weld metal formed by the trailing electrode is cracked, but also an overlap due to an excessive amount of welding and an undercut are generated.

The L pole voltage V _L is in order to obtain sufficient penetration.
Must be 45 V or less. If it exceeds 45V, undercutting will occur on the flange side. T pole voltage V _T is 50V
It is necessary to: If it is larger than 50V, undercut will occur on the flange side. The L-pole electrode gradient (hereinafter “electrode gradient” is also simply referred to as “gradient”) a shown in FIG. 2 is an important parameter for efficiently obtaining sufficient penetration. If a is less than 3 °, the direction of fusion does not face the flange side, and the butt portion cannot be melted, resulting in insufficient fusion. If it is greater than 30 °, the direction of fusion enters too much on the flange side, and so does butt jointing. The part cannot be melted sufficiently, resulting in insufficient melting.

The same T pole gradient b shown in FIG. 2 is important for preventing undercuts and overlaps. If b is smaller than 3 °, the leg length on the flange side will be insufficient and 35 °
If it is larger, the toe on the web side has an overlapping shape, and an undercut occurs on the toe on the flange side. The L-pole electrode angle (hereinafter “electrode angle” is also simply referred to as “angle”) c shown in FIG. 3 is important for efficient penetration. If it deviates from the range of -10 to + 10 °, the concentration of the arc will worsen and insufficient penetration will occur.

The T pole angle d shown in the same FIG. 3 is important for adjusting the bead shape. If it is smaller than 0 °, the bead shape becomes convex, and if it is larger than 30 °, undercut occurs on the flange side. Distance between the L and T poles is 10 to 120m
Must be m. If it deviates from this range, cracks will occur in the weld metal. On the other hand, if it exceeds 120 mm, the toe on the web side will have an overlapping shape, and the molten slag formed by the L pole will solidify, making the T pole arc unstable and making the bead uneven.

The shortest distance e between the L pole and the flange shown in FIG. 2 is an extremely important factor for obtaining a sufficient penetration depth. If it goes out of the range of 0 to 10 mm, the weld metal penetration end part shifts from the butt groove to cause insufficient penetration, and undercut occurs at the flange side toe part. The shortest distance f between the T pole and the flange shown in FIG. 2 is a very important factor for preventing the undercut on the flange side and the overlap on the web side. If the shortest distance between the T pole and the flange is less than 1 mm, undercut occurs on the flange side and the web side is likely to have an overlap shape. If it is larger than 13 mm, the leg length on the flange side cannot be obtained sufficiently.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiment of the present invention is shown in the conceptual diagram of FIG. 1
Is a web, 2 is a flange, and web 1 is in a horizontal position,
4a and 4b are a pair of electrodes for simultaneously welding the T joints on both sides of the web 1. Hereinafter, examples will be described with respect to the limiting content of the welding conditions constituting the present invention for each plate thickness, groove, and penetration condition of the web material. However, the following data relates to the T-joint on one side, and simultaneous welding on both sides under the same welding conditions is extremely easy as long as the web is in a horizontal posture.

[0026]

[Table 1]

[0027]

[Table 2]

[0028]

[Table 3]

[0029]

[Table 4]

Table 4 shows the welding H in which the web material according to claim 2 of the present invention is a thick steel plate having a plate thickness of 16 mm to 32 mm.
Examples No. 1 to No. 13 of two-electrode horizontal fillet latent arc welding without a groove in the production of shaped steel are shown. An AC power supply was used for both the leading electrode and the trailing electrode, and welding was performed as an inverted V connection. Table 1 shows the chemical composition of the steel sheet used, Table 2 shows the chemical composition of the wire, and Table 3 shows the composition of the flux using the firing type.

[0031]

[Table 5]

Table 5 shows a comparative example of the present invention corresponding to Table 4.
Indicates No.14 to No.29. In No. 14, since the L pole wire diameter is small, the penetration tip deviates from the groove abutment part, insufficient penetration occurs, and slag entrainment also occurs. N
At o.15, the diameter of the T pole wire was small, and the bead was convex, and the bead appearance deteriorated. In No. 16, since the ratio of the T pole current to the L pole current was small, slag entrainment and cracking occurred. In No. 17, the voltage of the L pole was high and undercut and insufficient penetration occurred. In No. 18, the voltage of the T pole was high and undercut occurred. In No. 19, the current ratio was high, causing overlap and insufficient penetration. In No. 20, the L pole gradient was large, and insufficient penetration occurred. In No. 21, the T pole inclination was large and an undercut occurred. In No. 22, the L pole angle was large and insufficient penetration occurred. In No. 23, the T pole angle was large and undercut occurred. In No. 24, the distance between the poles was large, and welding cracks and overlap occurred. In No. 25, the distance between the flange and the L pole was small, resulting in insufficient penetration and undercut. In No. 26, the distance between the flange and the T pole was large, and the leg length was insufficient. No.27
In, the distance between the flange and the T pole was small, and undercut occurred. In No. 28, the wire diameter of the L pole was large, so insufficient penetration occurred. In No. 29, the wire diameter of the T pole was large, so undercut occurred on the flange side.

[0033]

[Table 6]

In Table 6, Welding H in which the web material according to claim 3 of the present invention is a thick steel plate having a plate thickness exceeding 16 mm and up to 60 mm
2) by the partial penetration method with a groove for forming steel
Examples No. 30 to No. 38 of horizontal electrode fillet latent arc welding are shown.

[0035]

[Table 7]

Table 7 shows comparative examples corresponding to Table 6.
No. 39 to No. 46 are shown. In No. 39, the groove depth is small,
Insufficient penetration occurred. In No. 40, the groove angle was large, so unmelted parts remained in the groove. No. 41 had a narrow groove angle, so slag entrainment occurred. No.42 is L
Due to the high polar voltage, insufficient penetration and undercut occurred. In No. 43, the current ratio was high and undercut and overlap occurred. In No. 44, the leading electrode wire was thick, so insufficient penetration occurred. In No. 45, the T pole angle was large, so undercut occurred. In No. 46, the gap between the electrodes was small, so cracks occurred in the weld metal.

[0037]

[Table 8]

Table 8 shows the welding H in which the web material corresponding to claim 4 of the present invention is a thick steel plate having a plate thickness of 16 mm to 60 mm.
2) by the complete penetration method with a rectangular groove for shaped steel
Examples No. 47 to No. 56 of horizontal electrode fillet latent arc welding are shown.

[0039]

[Table 9]

Table 9 shows comparative examples corresponding to Table 8.
No.57 to No.64 are shown. No. 57 has a small groove depth,
Insufficient penetration occurred. In No. 58, the groove angle was large and the groove remained unmelted. No.59 has a narrow groove angle,
Entrapment of slag occurred. In No. 60, the groove depth was too deep and melted down. In No. 61, the distance between the L pole and the flange was large, penetration was insufficient, and overlap occurred. N
At o.62, the T pole inclination was large and undercut occurred. In No. 63, the L pole wire diameter was small and the penetration was deep, causing burn-through. In No. 64, the T pole angle is large,
Undercut has occurred.

[0041]

As described in detail above, according to the present invention, since welding can be performed while holding the web of the work piece in a horizontal position, the tilting work of the work piece which has been conventionally performed is unnecessary, and the cost is reduced. It is an industrially very effective technology that can shorten the delivery time, etc. Furthermore, by simultaneously welding both ends, it is possible to further reduce the production man-hours.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing a welding situation in an example of the present invention.

FIG. 2 is an explanatory diagram showing a distance between a flange and an electrode and an electrode inclination in the present invention.

FIG. 3 is an explanatory diagram showing an electrode angle and a distance between electrodes in the present invention.

FIG. 4 is an explanatory view showing a welding method in the conventional technique.

FIG. 5 is an explanatory view showing a welding method in another conventional technique.

FIG. 6 is an explanatory view showing the shape of a welded portion in the conventional technique.

FIG. 7 is an explanatory diagram showing welding defects in the conventional technique.

FIG. 8 is a conceptual diagram showing a welding situation in the conventional technique.

FIG. 9 is a conceptual diagram showing a welding situation in still another conventional technique.

[Explanation of symbols]

1 web 2 flange 3 welded portion 4 electrodes 4L L pole 4T T pole I _T / I _L L ratio of electrode current and the T electrode current V _L L pole voltage V _T T pole voltage a L-pole electrode slope b T-pole electrode slope c L pole electrode angle d T pole electrode angle e Shortest distance between L pole and flange f Shortest distance between T pole and flange l Distance between L pole and T pole t Plate thickness

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical display location B23K 33/00 B23K 33/00 Z (72) Inventor Shuichi Sakaguchi 1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba Prefecture Address Kawasaki Steel Co., Ltd. Technical Research Institute (72) Inventor Mitsutsugu Sugisaki 2-3 2-3 Uchisaiwaicho, Chiyoda-ku, Tokyo Inside Kawasaki Steel Co., Ltd. (72) Inventor Matsushima Nakajima 18 Showa-cho, Marugame, Kagawa Prefecture Kawatetsu Inside Metal Fabrica Co., Ltd.

Claims (5)

[Claims] 1. A two-electrode horizontal fillet for a T-joint, characterized in that, in a single-layer fillet welding of a T-joint whose web material is a thick steel plate, the web is placed in a horizontal posture and fillet welding is performed under the following welding conditions. Submerged arc welding method. Note: L pole wire diameter: 3.2 to 6.4 mm, T pole wire diameter: 3.2 to 7.
0 mm, the ratio of L-pole current and the T-pole current _{(I T / I L):} 0.6~
1.0, L pole voltage _{(V L): V L ≦} 45V, T pole voltage _{(V T): V T ≦} 50V, L -pole electrode gradient (a): 3 to 30
°, T pole electrode inclination (b): 3 to 35 °, L pole electrode angle (c): −10 to + 10 °, T pole electrode angle (d): 0 to 30
°, distance between L pole and T pole (l): 10 to 120 mm, shortest distance between L pole and flange (e): 0 to 10 mm, shortest distance between T pole and flange (f): 1 to 13 mm. 2. The two-electrode horizontal of the T-joint according to claim 1, wherein the web material is a thick steel plate having a plate thickness of 16 mm to 32 mm and the fillet welding is fillet welding without groove processing by the partial penetration method. Fillet submerged arc welding method. 3. The web material is a thick steel plate having a plate thickness (t) of more than 16 mm and 60 mm, and fillet welding is carried out on both sides of the web with a groove angle of 30 to 65 °, and a plate thickness (1/5 ~ 1/3) The two-electrode horizontal fillet latent arc welding method for a T-joint according to claim 1, which is fillet welding by a partial penetration method provided with a groove groove having a depth of t. 4. The web material is a thick steel plate having a plate thickness (t) of from 16 mm to 60 mm, and fillet welding is carried out at a groove angle of 30 to 65 ° on both sides of the web, with respect to the plate thickness (1/5 5-12) The two-electrode horizontal fillet latent arc welding method for a T-joint according to claim 1, which is fillet welding by a complete penetration method provided with a grooved groove of t depth. 5. A two-electrode horizontal fillet for a T-joint in the production of a welded H-section steel, characterized in that the single-layer fillet welding according to any one of claims 1 to 4 is performed simultaneously at the T-joints at both ends of the web. Submerged arc welding method.