JP5953744B2 - Groove for corner welding of welded four-sided box-shaped cross-section members - Google Patents

Description

  The present invention relates to a groove portion for corner welding of a welded and assembled four-sided box-shaped cross-section member suitable for a box column of a building structure.

FIG. 13 shows a cross-sectional shape of a welded and assembled four-sided box-shaped cross-section member that is often used as a box column in the construction field. The flange plate 1 and the web plate 2 are combined into a box-shaped cross section, and a “le-shaped” groove (see FIG. 12 (a)), “I” groove (FIG. 12 (b)), “V” groove (FIG. 12 (c)), or “I + V” groove (see FIG. 12 (d)) (for example, Patent Document 1) is assembled by welding and joining the corners a. In any groove shape, a backing metal 4 is attached to the bottom surface of the gap between the flange plate 1 and the web plate 2.
In the case of the “le-shaped” groove and the “I-shaped” groove, the groove processing is performed only on the web plate 2. Even in the “V-shaped” and “I + V-shaped” grooves (FIG. 12D), the flange plate 1 is welded and assembled in a four-sided box shape so that the corners are subjected to an extremely simple groove machining. The backing metal 4 is often attached at a right angle to the flange plate 1 at the corners of the cross-sectional member.

JP 2007-313524 A

By the way, when a steel material is welded, a heat affected zone is formed in the steel material joined by the welding heat, and strength and toughness deteriorate in this heat affected zone. FIGS. 9 and 10 show the heat applied to a welded joint manufactured by using CO ₂ gas welding and submerged arc welding (SAW) using a 590 N / mm ^second grade steel material (plate thickness 40 mm) and a 590 N / mm ^second grade welding material. The Charpy impact test results (test temperature 0 ° C.) of the affected part and DEPO are shown. Table 1 shows the mechanical properties of the materials used.

In CO ₂ gas welding and submerged arc welding (SAW), the heat input was controlled to be about 30,000 J / cm and 60,000 J / cm, respectively, and the interpass temperature was set to 150 ° C. or less.

  FIG. 11 shows the sampling position and notch position of the Charpy impact test piece. The notch was a side notch and was sampled so that its center was at a position of 1/4 of the plate thickness.

  Further, generally, defects such as insufficient welding of the weld metal are likely to occur at the corners of the first weld layer, which tends to be a starting point for brittle fracture.

  FIG. 2A is a view for explaining a corner welded portion of the flange plate 1 and the web plate 2 in the welded assembly four-sided box-shaped cross-section member, and around the weld metal 5 there is a heat affected zone 6 having deteriorated strength and toughness. The first layer weld 8 is located on the extension line of the slight gap 7 between the backing metal 8 and the flange plate 1. FIG. 2 (b) is a diagram schematically showing a case where a corner welded portion is brittle fracture. When deformed by receiving stress from a member such as a beam to be joined, the gap between the backing metal 4 and the flange plate 1 is shown. Stress concentrates locally at the tip of the minute gap 7 and a crack is generated, and a brittle fracture is likely to occur in the weld heat affected zone 6.

  In the case of the groove shown in FIGS. 12 (a) to 12 (d), the welding first layer corner portion 8 is positioned in the immediate vicinity of the gap 7, and the weld metal 5 is filled along the flange plate 1. Since the heat-affected zone 6 in which the strength and toughness continuously deteriorates and extends easily and propagates is located almost on the extended line, the corner welded portion is likely to break.

FIGS. 7A to 7C are explanatory diagrams of FEM analysis performed to verify this phenomenon, and model the deformation state of the welded assembly four-sided box section column 11 at the time of earthquake. FIG. 7A is an FEM analysis model, FIG. 7B is a schematic diagram showing a deformation state in the column beam joint portion 9, and FIG. 7C is an enlarged view of a portion of FIGS. The welding assembly tetrahedral box shape cross section column 11 590N / mm ² class steels, the beam member 10 is 490 N / mm ² grade steel welding material corner for welding 590N / mm ² class welding assembly tetrahedral box shape cross section column 11 Is assumed. Table 2 shows the mechanical properties of the materials used.

  In the analysis, as shown in FIG. 7, a load was applied to both ends of the beam 10, and the state of occurrence of plastic strain when the member deformation angle of the beam 10 reached 1/100 rad was verified.

  FIG. 8 shows a result of the analysis, and represents a plastic strain contour diagram. As the color is darker, the plastic strain is concentrated, that is, cracks are more likely to occur. From FIG. 8, it can be confirmed that strain concentrates in the vicinity of a minute gap generated between the backing metal 4 and the flange plate 1 and that a crack can be easily generated.

  Therefore, when the heat-affected zone with deteriorated toughness and strength is positioned linearly directly above the gap, it is assumed that the generated crack easily develops and the entire cross section of the weld zone is broken.

  Then, an object of this invention is to provide the groove part for corner welding of the welded four-sided box-shaped cross-section member which solves the said problem.

The object of the present invention can be achieved by the following means.
1. A groove portion for corner welding of a welded four-sided box-shaped cross-section member for welding adjacent flange plates and web plates at the corners of the welded four-sided box-shaped cross-sectional member, wherein the groove portion is the welded four-sided box-shaped section In a cross section perpendicular to the longitudinal direction of the member, the flange plate, the web plate disposed with a gap with the flange plate, and a backing metal disposed at the bottom of the gap, the flange plate , Having a notch in at least a portion facing the web plate, and the notch is shaped so that the first layer welding on the flange plate side when welding the notch does not melt the backing metal. A groove portion for corner welding of a welded four-sided box section member.
2. The notch portion is formed by notching the flange plate with a straight line of at least two sides, and among the sides, the length of the side connected to the backing metal is 5 mm or more and 10 mm or less on the short side shorter than the other side. 2. A groove portion for corner welding of the welded four-sided box-shaped cross-section member according to 1.
3. The notch is formed by cutting the flange plate with a straight line of at least two sides, and among the sides, the side connected to the backing metal has a shorter side than the other side, and the short side and the other side 3. The angle welding groove portion of the welded four-sided box-shaped cross-section member according to 1 or 2, wherein an angle formed by the side is 90 ° or more and 120 ° or less.
4). The side has two sides, the long side has the same length as the thickness of the web plate, and the short side has a length that does not melt the backing metal in the first layer welding when welding the notch. 4. A groove portion for corner welding of a welded four-sided box-shaped cross-section member according to 2 or 3, which is rectangular.
5.1 to 4 Neu not Re or one to welding tetrahedral box-section member welded to the corner welding groove of the welding tetrahedral box-section member according.

  In the present invention, by providing a groove with a step on the wedge plate side of the flange plate, a minute gap between the backing metal and the flange plate, which is a stress concentration part, and a welding initial layer in which welding defects are likely to occur. Since the corners are not close to each other, cracks are hardly generated from the tip of the gap.

  Even if a crack occurs from the tip of the gap, the heat-affected zone with deteriorated strength and toughness is no longer positioned on the extension line of the gap, so the propagation path after the crack is complicated and the crack is difficult to progress. Therefore, it is possible to reduce the risk of early breakage in the corner welded portion, which is extremely useful industrially.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1A is a view for explaining a corner welding groove portion of a welded four-sided box-shaped cross-section member according to an embodiment of the present invention, and FIG. It is a figure explaining the corner welding part of the conventional welding four face box-shaped cross-section member, (a) is after welding, (b) is a figure which shows the fracture condition of a welding part. (A) is a figure which shows the groove part for corner welding of the welded four-sided box-shaped cross-section member which concerns on the other Example of this invention, (b) is a part of groove part for corner welding shown to (a). The figure which shows the groove part for square welding which deform | transformed. (A) is a figure which shows the groove part for corner welding of the welded four-sided box-shaped cross-section member which concerns on the other Example of this invention, (b) is a part of groove part for corner welding shown to (a). The figure which shows the groove part for square welding which deform | transformed. The figure which shows the groove part for square welding of the welded four-sided box-shaped cross-section member which concerns on the other Example of this invention. (A) is a figure which shows the groove part for corner welding of the welded four-sided box-shaped cross-section member which concerns on the other Example of this invention, (b) is a part of groove part for corner welding shown to (a). The figure which shows the groove part for square welding which deform | transformed. BRIEF DESCRIPTION OF THE DRAWINGS It is explanatory drawing of the FEM analysis implemented in order to demonstrate the phenomenon which the groove part for square welding of the welded quadrilateral box-shaped member which concerns on this invention makes a subject, (a) is a FEM analysis model, (b) is a column beam. The schematic diagram which shows the deformation | transformation state in a junction part, (c) is the a section enlarged view of (a) and (b). The figure which shows the analysis result of the FEM analysis model of FIG. Heat affected zone and DEPO Charpy impact test results (test temperature) for welded joints manufactured using 590N / mm grade ² steel (plate thickness 40mm) and 590N / mm grade ² welding material by CO ₂ gas welding FIG. Heat affected zone and DEPO Charpy impact test results (test temperature 0) conducted on a welded joint manufactured using 590 N / mm grade ² steel (plate thickness 40 mm) and 590 N / mm grade ² welding material by submerged arc welding FIG. The figure which shows the test piece collection position and notch position of the Charpy impact test of FIG. The figure which shows the groove shape of the conventional corner welding part, (a) is a re-shaped groove, (b) is an I-shaped groove, (c) is a V-shaped groove, and (d) is an I + V-shaped groove. Indicates. The figure which shows the cross-sectional shape of a welding assembly quadrilateral box-shaped cross-section member.

  The groove portion for corner welding of the welded four-sided box-shaped cross-section member according to the present invention is the first layer in which defects are likely to occur on the extension line of the gap between the backing metal and the flange plate when the flange plate and the web plate are welded. It is characterized by having a groove shape in which the welded part and the welded heat affected zone with low strength and toughness are not located.

  FIG. 1 is a diagram showing a corner welding groove portion of a welded four-sided box-shaped cross-section member according to an embodiment of the present invention in a cross section perpendicular to the longitudinal direction, as a notch portion of a flange plate facing a web plate. The case where the first layer welding at the time of welding does not melt the backing metal is shown in the case of a substantially rectangular cutout.

  1A shows a state before welding and FIG. 1B shows a state after welding of a groove portion for corner welding shown in FIG. 1A. In these drawings, 1 is a flange plate, 2 is a web plate, and 3 is an open position. The tip space, 4 is a backing metal, 5 is a weld metal, 6 is a weld heat affected zone, 7 is a gap between the flange plate 1 and the backing metal 4, and 8 is a first layer weld.

  The groove portion shown in FIG. 1 (a) is a groove portion for corner welding for welding the flange plate 1 and the web plate 2 adjacent to each other at the corner portion of the welded four-sided box section member. In a cross section perpendicular to the longitudinal direction of the cross-section member, the flange plate 1, the web plate 2 disposed with a gap from the flange plate 1, and the flange plate 1 are in contact with each other, and are disposed across the web plate 2 from the bottom of the gap. The backing metal 4 is made up of.

  The flange plate 1 has a substantially rectangular notch at a portion facing the web plate 2. The notch portion has a length 1v of the long side 3a that is the same as the thickness of the web plate 2, and a length 1h of the short side 3b that is connected to the backing metal 4 at least when the notch portion is welded. The length is set so that the first layer welding 8 does not melt the backing metal 4.

  The groove space 3 filled with the weld metal 5 in the groove portion according to the present invention has a substantially rectangular cutout portion of the long side 3a and the short side 3b and an extension of the side surface where the backing plate 4 is in contact with the flange plate 1. It is composed of a space surrounded by a line (not shown) and the end surface of the wedge plate 2 on the flange plate 1 side.

  FIG. 1B shows a state after welding of the groove portion shown in FIG. 1A. In the corner welding, the flange plate 1 side and the wedge plate 2 on the bottom face of the backing metal 4 side of the groove space 3 are shown. Although the first layer weld 8 is formed on the side, in the present invention, the length 1h of the short side 3b connected to the backing metal 4 is at least a length at which the first layer welding does not melt the backing metal 4. The first layer weld 8 and the weld heat affected zone 6 when the long side 3 is welded are relatively not easily located on the extension line of the gap 7.

  In the welded four-sided box section member according to the present invention, even if the stress from the beam acts on the corner weld and a crack is generated at the tip of the gap 7, the weld heat affected zone 6 along the flange plate 1 is cracked. Since it is not on the extension line, the risk of brittle fracture is reduced.

  Immediately above the gap 7, the welding heat affected zone 6 is positioned orthogonal to the gap 7, but the toughness of the weld metal 5 is improved, the backing metal 4 and the flange plate 1 where the weld heat affected zone 6 is generated It is only necessary to use a steel material with high toughness to prevent crack propagation.

  When reducing the risk of brittle fracture at a corner weld in an actual structure, it is necessary to separate the strain concentration site from the heat affected zone by 5 mm or more in FIG. Considering that the root gap is about 7 mm to 8 mm for the root groove and about 15 mm at the maximum for the I-shaped groove in order to fill it with welding reasonably without generating, the length of the short side 3b The length 1h is preferably 5 mm or more and 10 mm or less, and more preferably, the angle Ra formed by the long side 3a and the short side 3b is 90 ° or more and 120 ° or less in order to facilitate groove processing.

  FIGS. 3 to 6 show a groove portion for corner welding of a welded four-sided box section member according to another embodiment of the present invention. In these figures, the same components as those in FIG.

  FIG. 3 shows a case where the web plate 2 has a “let-shaped” groove with the side facing the flange plate 1 as a hypotenuse, and FIG. 3A shows a substantially rectangular notch in the portion of the flange plate 1 facing the web plate 2. (B) is a case where the portion facing the web plate 2 of the flange plate 1 is cut off at two sides, and the angle Ra between the short side connected to the backing metal 4 and the other side exceeds 90 ° Indicates.

  FIG. 4 is a case of an “I” groove with the web plate 2 facing the flange plate 1 parallel to the flange plate 1, and FIG. 4A shows the portion of the flange plate 1 facing the web plate 2. In the case of having a substantially rectangular notch, (b) shows a plane where the flange plate 1 and the backing metal 4 are in contact with each other as the axis of symmetry, the thickness of the web plate 2 as one side, and a part of the backing metal 4 The notch shape with two sides with the cut-out length as the other side and the angle Rb formed by both sides exceeding 90 ° is also the flange plate 1 side with the plane where the flange plate 1 and the backing metal 4 are in contact as the axis of symmetry. The formed “deformed I” case is shown. An angle Ra formed between the side connected to the backing metal 4 on the flange plate 1 side and the other side is equal to the angle Rb.

  FIG. 5 shows that the side of the web plate 2 facing the flange plate 1 is the hypotenuse, the plane where the flange plate 1 and the backing metal 4 are in contact is the axis of symmetry, and the side of the flange plate 1 side facing the web plate 2 is the hypotenuse. The case of the “substantially V-shaped” groove is shown.

  FIG. 6 shows an “I + V-shaped” groove portion in which the cut-out portion is constituted by three sides. FIG. 6A is a cut-out portion at the side that opens the skin plate side of the groove portion in FIG. In this case, FIG. 4B shows a case where the skin plate side of the groove portion in FIG.

  The above description has been made on the groove shape in the cross section perpendicular to the longitudinal direction of the groove portion for corner welding of the welded four-sided box section member according to the present invention. The groove portion for corner welding is provided with the groove shape in an arbitrary cross section in the longitudinal direction of the member.

1 flange plate 2 web plate 3 groove space 4 backing metal 5 weld metal 6 weld heat affected zone 7 gap 8 first layer weld zone

Claims (5)

  A groove portion for corner welding of a welded four-sided box-shaped cross-section member for welding adjacent flange plates and web plates at the corners of the welded four-sided box-shaped cross-sectional member, wherein the groove portion is the welded four-sided box-shaped section In a cross section perpendicular to the longitudinal direction of the member, the flange plate, the web plate disposed with a gap with the flange plate, and a backing metal disposed at the bottom of the gap, the flange plate , Having a notch in at least a portion facing the web plate, and the notch is shaped so that the first layer welding on the flange plate side when welding the notch does not melt the backing metal. A groove portion for corner welding of a welded four-sided box section member.   The notch portion is formed by notching the flange plate with a straight line of at least two sides, and among the sides, the length of the side connected to the backing metal is 5 mm or more and 10 mm or less on the short side shorter than the other side. A groove portion for corner welding of the welded four-sided box-shaped cross-section member according to claim 1.   The notch is formed by cutting the flange plate with a straight line of at least two sides, and among the sides, the side connected to the backing metal has a shorter side than the other side, and the short side and the other side The angle portion formed by the side is 90 ° or more and 120 ° or less, and the groove portion for corner welding of the welded four-sided box section member according to claim 1 or 2.   The side has two sides, the long side has the same length as the thickness of the web plate, and the short side has a length that does not melt the backing metal in the first layer welding when welding the notch. The groove portion for corner welding of a welded four-sided box-shaped cross-section member according to claim 2 or 3, wherein the groove portion is rectangular. 5. A welded four-sided box-shaped cross-section member , wherein the gap is filled with a weld metal in a corner welding groove portion of the welded four-sided box-shaped cross-section member according to any one of claims 1 to 4.