JPH1177301A - Cladding method by welding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the occurrence of cracks in case of earthquake or the like by imparting toughness to the weld zone of a steel structural member and thereby enhancing deformability. SOLUTION: Using a welding rod having lower yield strength than the base metal, dressing welding 7a, 7b, 7c is carried out in such a manner as to cover at least the weld heat affected part of the main weld zone, stress concentrated part of the weld bead toe part, or deteriorated part 5a, 5b of the material, in the weld zone 6 of a steel structural member 1. As a result, using heat generation accompanied with the plastic deformation of dressing bead at the time of earthquake, temperature is raised at the weld heat affected part or the weld bead toe part, so that brittle fracture is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a build-up welding method capable of preventing brittle fracture from a stress-concentrated portion or a heat-affected zone in a weld.

[0002]

2. Description of the Related Art Conventionally, brittle fractures originating from a welded heat-affected zone, a scallop, a bottom / backing metal, or a tack welded portion such as an end tab have been generated in a welded portion such as a column / beam joint. It is a problem.

Therefore, as shown in, for example, Japanese Patent Application Laid-Open No. 52-98642, a high strength welding material is used to reinforce a welded metal joint at a location where fatigue cracks easily occur or in the vicinity thereof. A joint welding method has been proposed in which decorative welding is performed to increase fatigue strength and relax residual stress.

[0004]

However, in the case of performing a decorative welding of a welded metal joint with a high-strength welding material, the welded joint lacks elasticity (toughness), causing an earthquake or the like. In this case, there is a problem that cracks are easily generated.

[0005] In order to improve the deformability of a steel structural member, it is important to prevent brittle destruction. Steel materials tend to cause brittle fracture when the temperature is low, but the starting point is the weld heat-affected zone in the welded portion such as the column / beam joint, the scallop, the bottom / backing metal, or the temporary welded portion such as the end tab. In brittle fracture, brittle fracture can be prevented by increasing the temperature of the starting point.

A technical object of the present invention is to provide a welded portion of a steel structural member with a toughness to improve the deformability and prevent occurrence of cracks in the event of an earthquake or the like.

[0007]

According to a first overlay welding method of the present invention, at least a weld heat-affected zone of a main welded portion or a stress concentrated portion of a weld bead toe at a welded joint of a steel structural member. By using a welding rod with a lower yield strength than the base metal to cover, we use the heat generated by plastic deformation of the decorative bead during an earthquake to make use of the heat generated by the weld heat affected zone or the weld bead toe. , To prevent brittle fracture.

In the first overlay welding method of the present invention, when a tensile load is applied to the weld joint during an earthquake, the decorative bead is first plastically deformed and generates heat. Then, the heat generated by the plasticization of the decorative bead portion raises the temperature of the weld heat-affected zone of the main weld portion or the stress concentration portion of the weld bead toe portion, thereby preventing brittle fracture.

The second overlay welding method according to the present invention covers at least a tack welded portion, a material degraded portion, or a stress / strain concentrated portion which is expected to be a starting point of brittle fracture in a welded joint of a steel structural member. In addition, by using a welding rod with a lower yield strength than the base material, make-up welding is used to make use of the heat generated by plastic deformation of the decorative bead during an earthquake, and to make use of the heat generated by tack-welding, material deterioration, or stress / strain concentration. It is characterized in that the temperature of the site is raised to prevent brittle fracture.

In the second overlay welding method of the present invention, when a tensile load is applied to the weld joint during an earthquake, the decorative bead is first plastically deformed and generates heat. Then, the temperature of the tack welded portion, the material deterioration portion, or the stress / strain concentration portion, which is expected to be a starting point of brittle fracture in the welded portion due to heat generated by plasticization of the decorative bead portion, is increased, and brittle fracture is prevented. .

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. Hereinafter, the present invention will be described with reference to the illustrated embodiments. FIG. 1 is an explanatory view showing a first embodiment in which the overlay welding method according to the present invention is applied to scallops. As shown in the figure, scallops 3 formed at the end of a web 2 of H-section steel 1
a, 3b, that is, a continuous portion 5a from the web 2 on the outer side of the scallop, which becomes a material deterioration portion by forming the scallop 3a, 3b, to the upper and lower flanges 4a, 4b.
5b and on the surface of the weld bead of the butt weld 6 at the end of the web 2, respectively, using a welding rod having a lower yield strength and a higher elongation ability than the base metal, and using the welding rods 7 a, 7 b, 7.
c is formed.

In the overlay welding method of this embodiment, when a tensile load is applied to the welded joints and the continuous portions 5a, 5b during an earthquake, the decorative welds 7a, 7b, 7c are plastically deformed and generate heat. Then, due to the heat generated by the plasticization of the decorative bead portion, the material degraded portions, that is, the continuous portions 5a and 5b which are expected to be the starting points of the weld heat affected zone and the brittle fracture of the main weld zone.
The temperature of the butt-welded portion 6 at the tip of the web 2, which becomes the stress / strain concentration site, is increased, and brittle fracture is prevented.

Embodiment 2 FIG. FIG. 2 is an explanatory view showing a second embodiment in which the overlay welding method according to the present invention is applied to an end tab. Note that the tab used here does not hinder the finishing material and is not cut. As shown in the figure, the tack welding portion 13 of the tabs 12a and 12b attached on the extension of the welding line at both ends of the butt welding portion of the plate 11 and the plate 11
Are formed on the surface of the weld bead at the joint of the welded portions 14 by using welding rods having a lower yield strength and a higher elongation ability than the base metal, respectively.

In the overlay welding method of this embodiment,
When a tensile load is applied to the welded joint during an earthquake, the decorative welds 7d and 7e are plastically deformed and generate heat. Then, due to the heat generated by the plasticization of the decorative bead portion, the temperature of the tack weld portion 13 of the tabs 12a and 12b, which is expected to be a starting point of brittle fracture, is increased, and brittle fracture is prevented.

Embodiment 3 FIG. 3 is an explanatory view showing a third embodiment in which the build-up welding method according to the present invention is applied to butt welding in which back welding is performed after backlashing. As shown in the figure, on both side edges of the surface of the uppermost weld bead of the re-shaped butt weld portion 22 of the plate material 21 and on the back surface of the post-hanging weld portion 23, the yield strength is lower and the elongation ability is higher than that of the base material. Decorative welds 7f, 7g, 7h are formed using a welding rod.

In the overlay welding method of this embodiment,
When a tensile load is applied to the welded joint during an earthquake, the decorative welds 7f, 7g, and 7h are plastically deformed and generate heat. Then, due to the heat generated by the plasticization of the decorative bead portion, the temperatures of the weld heat-affected portions 24a and 24b of the main weld portion and the back welded portion 22 on the back side are increased, and brittle fracture is prevented.

Embodiment 4 FIG. 4 shows a fourth example in which the overlay welding method according to the present invention is applied to a butt welding using a backing material.
FIG. 4A shows an example of direct joining to a steel pipe column or the like, and FIG. 4B shows an example of joining a steel pipe column to a diaphragm. (A) and (b), as shown in the figure, both side edges of the surface of the uppermost weld bead of the re-shaped butt welded portion 33 of the plate material 32 using the backing material 31, and the temporary welding portions 34a, 34b of the backing material 31 On the surface of 34b, decorative weld portions 7i, 7j, 7k, 7l are formed using welding rods having a lower yield strength and a higher elongation ability than the base material, respectively.

In the overlay welding method of this embodiment,
When a tensile load is applied to the welded joints during an earthquake, the decorative welds 7i, 7j, 7k, 7l are plastically deformed and generate heat.
And, by the heat generated by plasticization of this decorative bead part,
The temperatures of the weld heat affected zones 35a and 35b of the main weld and the tack welded zones 34a and 34b, which are expected to be the starting points of brittle fracture, are increased, and brittle fracture is prevented.

Embodiment 5 FIG. 5 is an explanatory view showing a fifth embodiment in which the overlay welding method according to the present invention is applied to fillet welding. As shown in the figure, on both side edges of the surface of the fillet welded portions 42a and 42b on both sides of the plate material 41,
Decorative welds 7m, 7n, 7o, 7p using welding rods having lower yield strength and higher elongation ability than the base material, respectively.
Is formed.

In the overlay welding method of this embodiment,
When a tensile load is applied to the weld joint during an earthquake, the decorative welds 7m, 7n, 7o, and 7p are plastically deformed and generate heat.
And, by the heat generated by plasticization of this decorative bead part,
The temperature of the weld heat affected zone of the main weld is increased, and brittle fracture is prevented.

Embodiment 6 FIG. 6 is an explanatory view showing a sixth embodiment in which the build-up welding method according to the present invention is applied to flared welding. As shown in the figure, on both side edges of the surface of the welded portion 52 of the corner of the L-shaped plate member 51, using a welding rod having a lower yield strength and a higher elongation ability than the base material, respectively, the decorative weld portions 7q and 7r. Is formed.

In the overlay welding method of this embodiment,
When a tensile load is applied to the weld joints during an earthquake, the decorative welds 7q and 7r are plastically deformed and generate heat. Then, due to the heat generated by the plasticization of the decorative bead portion, the temperature of the weld heat affected zone of the main weld zone is increased, and brittle fracture is prevented.

In each of the above-described embodiments, an example is described in which the decorative weld is formed at a specific portion of the surface of the main weld. However, the decorative weld is formed on the surface of the main weld. May be formed so as to cover the entire area, and in this case, the heat generation effect by plasticizing the decorative bead portion can be further enhanced.

[0024]

As described above, according to the present invention, at least the welding heat affected zone of the main welded portion or the stress concentrated portion of the weld bead toe at the welded joint portion of the steel structural member is covered. Welding with a welding rod having a lower yield strength than that of the material, and using the heat generated by plastic deformation of the decorative bead when a tensile load is applied to the weld joint during an earthquake, the effect of welding heat on the main weld Since the temperature of the stress concentrated portion of the welded portion or the toe of the weld bead is increased, it is possible to prevent brittle fracture of the weld heat affected zone of the main welded portion or the stress concentrated portion of the weld bead toe.

Further, according to the present invention, the base metal is formed so as to cover at least a tack welded portion, a material degraded portion or a stress / strain concentrated portion which is expected to be a starting point of brittle fracture in a welded joint of a steel structural member. Welding using a welding rod with a lower yield strength than that of the welded joint, and using the heat generated by the plastic deformation of the decorative bead when a tensile load is applied to the weld joint during an earthquake, the tack weld or the material deterioration Alternatively, since the temperature of the stress / strain concentration portion is increased, brittle fracture of the tack welded portion, the material deterioration portion, or the stress / strain concentration portion can be prevented.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a first embodiment in which a build-up welding method of the present invention is applied to scallops.

FIG. 2 is an explanatory view showing a second embodiment in which the overlay welding method of the present invention is applied to an end tab.

FIG. 3 is an explanatory view showing a third embodiment in which the build-up welding method of the present invention is applied to a butt welding in which back welding is performed after a back suspension.

FIG. 4 is an explanatory view showing a fourth embodiment in which the overlay welding method of the present invention is applied to a butt welding using a backing material.

FIG. 5 is an explanatory diagram showing a fifth embodiment in which the overlay welding method of the present invention is applied to fillet welding.

FIG. 6 is an explanatory view showing a sixth embodiment in which the overlay welding method of the present invention is applied to flared welding.

[Explanation of Signs] 1 H-section steel (steel structural member) 3a, 3b Scallop (material deterioration part) 5a, 5b Continuous part (material deterioration part) 6 Butt weld (stress / strain concentration part) 7a, 7b, 7c, 7d, 7e, 7f, 7g, 7h, 7
i, 7j, 7k, 71, 7m, 7n, 7o, 7p, 7
q, 7r Decorative welds 11, 21, 32, 41 Plates (steel frame members) 12a, 12b Tabs 13, 34a, 34b Temporary welds 22, 33 Re-shaped butt welds 23 Back welds after suspension 24a, 24b , 35a, 35b Weld heat affected zone 42a, 42b Fillet weld zone 51 L-shaped plate (steel frame member) 52 Corner weld zone

Claims (2)

[Claims] 1. A welding rod having a lower yield strength than a base material so as to cover at least a weld heat affected zone of a main weld or a stress concentration zone of a weld bead toe at a weld joint of a steel structural member. By overlay welding, utilizing the heat generated by plastic deformation of the decorative bead during an earthquake, the temperature of the weld heat-affected zone or the weld bead toe is raised to prevent brittle fracture. Welding method. 2. A method for covering at least a tack-welded portion, a material-deteriorated portion, or a stress / strain concentrated portion, which is expected to be a starting point of brittle fracture in a welded joint of a steel structural member.
By using a welding rod with a lower yield strength than the base metal to make a decorative weld, the heat generated by plastic deformation of the decorative bead during an earthquake can be used to create a temporary welded part, a material deteriorated part, or a stress / strain concentrated part. An overlay welding method characterized by raising the temperature to prevent brittle fracture.