JP6051817B2 - Method for suppressing fatigue damage of welded structure, tool for forming impact mark used in the method, and welded structure - Google Patents
Method for suppressing fatigue damage of welded structure, tool for forming impact mark used in the method, and welded structure Download PDFInfo
- Publication number
- JP6051817B2 JP6051817B2 JP2012261047A JP2012261047A JP6051817B2 JP 6051817 B2 JP6051817 B2 JP 6051817B2 JP 2012261047 A JP2012261047 A JP 2012261047A JP 2012261047 A JP2012261047 A JP 2012261047A JP 6051817 B2 JP6051817 B2 JP 6051817B2
- Authority
- JP
- Japan
- Prior art keywords
- mark
- hitting
- tool
- forming
- weld bead
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 238000000034 method Methods 0.000 title claims description 33
- 230000006378 damage Effects 0.000 title claims description 26
- 239000011324 bead Substances 0.000 claims description 50
- 239000000463 material Substances 0.000 claims description 36
- 238000003466 welding Methods 0.000 claims description 15
- 230000015572 biosynthetic process Effects 0.000 claims description 14
- 238000009751 slip forming Methods 0.000 claims description 4
- 230000035882 stress Effects 0.000 description 30
- 229910000831 Steel Inorganic materials 0.000 description 11
- 239000010959 steel Substances 0.000 description 11
- 239000010953 base metal Substances 0.000 description 6
- 230000000052 comparative effect Effects 0.000 description 6
- 230000001629 suppression Effects 0.000 description 4
- 238000007664 blowing Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 239000012141 concentrate Substances 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 230000035939 shock Effects 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 101100334009 Caenorhabditis elegans rib-2 gene Proteins 0.000 description 1
- 230000032683 aging Effects 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 239000002360 explosive Substances 0.000 description 1
- 238000007689 inspection Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 231100000241 scar Toxicity 0.000 description 1
Landscapes
- Golf Clubs (AREA)
Description
本発明は、鋼橋などの溶接構造物において、溶接部に疲労き裂などの疲労損傷が発生するのを抑制する溶接構造物の疲労損傷抑制方法、その方法に用いられる打撃痕形成用工具、および溶接構造物に関する。 The present invention relates to a method for suppressing fatigue damage of a welded structure that suppresses occurrence of fatigue damage such as fatigue cracks in a welded part in a welded structure such as a steel bridge, a tool for forming a hitting mark used in the method, And a welded structure.
近年、鋼橋の老朽化に伴い腐食や疲労に伴う損傷事例の報告が増加している。これらの防止には、まず検査体制を確立することが必要であるが、特に疲労損傷の場合は、通過車両などの作用外力を軽減したり、設計製作の面から溶接品質を向上させたりすることが重要である。
鋼橋などの溶接構造物では、割れなどの欠陥が溶接部に生じたり、溶接ビードの形状が不適で応力集中が溶接ビードの止端（溶接ビードを形成する溶接金属の表面が金属製部材（母材）の表面と交わる境界）に発生したりすると、繰り返し応力による影響と溶接残留応力の影響が重畳して疲労き裂が溶接部に発生しやすくなり、疲労破壊をもたらす場合がある。
In recent years, with the aging of steel bridges, reports of damage cases due to corrosion and fatigue are increasing. In order to prevent these problems, it is necessary to establish an inspection system first. However, especially in the case of fatigue damage, it is necessary to reduce external forces such as passing vehicles and improve welding quality from the viewpoint of design and production. is important.
In welded structures such as steel bridges, defects such as cracks occur in the welded part, the weld bead shape is inappropriate, and the stress concentration is the toe of the weld bead (the surface of the weld metal forming the weld bead is a metal member ( If it occurs at the boundary crossing the surface of the base material), the influence of repeated stress and the influence of welding residual stress are superimposed, and fatigue cracks are likely to occur in the welded part, resulting in fatigue failure.
このような疲労破壊を抑制するため、特許文献１〜３には、溶接ビードの止端に圧縮残留応力を導入して溶接部の疲労強度を向上させる方法が記載されている。
特許文献１には、溶接部の疲労強度向上方法およびそれを用いた溶接構造物に関し、溶接ビードの止端近傍を超音波振動しながら打撃して塑性変形させる加工装置により、特定寸法の溝を所定の打撃条件で加工することで高速に作業者の熟練度に依存しないで安心して疲労強度を向上させることが記載されている。
In order to suppress such fatigue failure, Patent Documents 1 to 3 describe a method of improving the fatigue strength of the welded portion by introducing compressive residual stress to the toe of the weld bead.
Patent Document 1 relates to a method for improving the fatigue strength of a welded portion and a welded structure using the welded portion. It is described that the fatigue strength can be improved with peace of mind without depending on the skill level of the worker at high speed by processing under a predetermined striking condition.
また、特許文献２には、レーザ衝撃ピーニング方法に関し、レーザ光源からのパルスレーザビームを使用して、表面の薄層、もしくはプラズマを形成する表面のコーティングを瞬間的に気化させてその爆発力により表面の一部に局所的に圧縮力を発生させる方法で、ガスタービンエンジンのファン動翼に圧縮残留応力を導入させることが記載されている。
更に、特許文献３には、溶接継手の疲労特性改善打撃処理方法及びその装置に関し、先端が特定寸法の打撃ピンを用いて、溶接止端に打撃痕による特定寸法の溝部が形成されるように鋼材表面を圧縮して溶接部に圧縮残留応力を導入することが記載されている。
Further, Patent Document 2 relates to a laser shock peening method, which uses a pulsed laser beam from a laser light source to instantaneously vaporize a surface thin layer or a coating on a surface that forms plasma, by using its explosive force. It is described that compressive residual stress is introduced into a fan blade of a gas turbine engine by a method in which a compressive force is locally generated on a part of the surface.
Furthermore, Patent Document 3 relates to a method and apparatus for improving the fatigue characteristics of a welded joint so that a groove having a specific size is formed at the weld toe by using an impact pin having a specific size at the tip. It describes that compressive residual stress is introduced into a welded portion by compressing the steel surface.
また、非特許文献１には、ハンマーピーニング及びＴＩＧ処理による高強度鋼（ＳＭ５７０）の溶接継手部の疲労強度向上法に関し、ハンマーピーニングを施すと疲労強度が低下する場合があるため、溶接止端の応力集中や残留応力を低減させる新たなハンマーピーニング法について検討した結果が記載されている。 Further, Non-Patent Document 1 relates to a method for improving the fatigue strength of a welded joint portion of high strength steel (SM570) by hammer peening and TIG treatment. The results of a study on a new hammer peening method that reduces the stress concentration and residual stress of the steel are described.
しかしながら、特許文献１に記載の方法は、溶接ビードの止端部に圧縮残留応力を導入する手段として、チップを超音波振動させて溶接ビードの止端に特定寸法の溝を加工する装置を用いるため、従来の空気圧でチップを駆動する装置と比較すると高価で入手も困難という問題点がある。
また、特許文献２に記載の方法は、溶接ビードの止端部に圧縮残留応力をレーザ衝撃ピーニングにより導入する方法であるため、素材の前処理が必要で、且つ装置が高価で大きく、鋼橋などの大形溶接構造物に適用することが難しいという問題点がある。
However, the method described in Patent Document 1 uses an apparatus that ultrasonically vibrates the tip to process a groove having a specific dimension at the toe of the weld bead as a means for introducing compressive residual stress into the toe of the weld bead. Therefore, there is a problem that it is expensive and difficult to obtain as compared with a conventional device for driving a chip with air pressure.
In addition, the method described in Patent Document 2 is a method of introducing compressive residual stress into the toe portion of the weld bead by laser shock peening, so that pretreatment of the material is necessary and the apparatus is expensive and large. There is a problem that it is difficult to apply to large welded structures such as.
更に、特許文献３に記載の方法は、溶接ビードの止端部に圧縮残留応力をハンマーピーニングにより導入する方法であるが、先端の曲率半径が２〜１０ｍｍの打撃ピンを母材表面に溶接金属に触れないように押し当てて圧縮残留応力を導入する方法であるため、圧縮残留応力を導入することが難しいという問題点がある。
また、非特許文献１には、ハンマーピーニングを施すと疲労強度が低下する場合があるため、溶接止端の応力集中や残留応力を低減させる新たなハンマーピーニング法について検討した結果が記載されているが、ハンマーピーニングは、通常、作業者がピーニング工具を工具先端が溶接ビードの止端に斜め上方から当たるように持って行われる。このため、図４に示すように、母材１の表面上にリブ２を直立させた面外ガセット継手にハンマーピーニングを施した場合、溶接ビード３の止端４に応力集中となる深い溝が形成され、溶接ビード３の止端４の近傍から疲労き裂が発生するおそれがある。
Furthermore, the method described in Patent Document 3 is a method in which compressive residual stress is introduced into the toe portion of the weld bead by hammer peening. A hammering pin having a tip radius of curvature of 2 to 10 mm is welded to the base metal surface. However, it is difficult to introduce the compressive residual stress because it is a method of introducing the compressive residual stress by pressing so as not to touch.
In addition, Non-Patent Document 1 describes the results of studying a new hammer peening method for reducing the stress concentration and residual stress at the weld toe because fatigue strength may decrease when hammer peening is performed. However, hammer peening is usually performed by an operator holding the peening tool so that the tip of the tool hits the toe end of the weld bead from obliquely above. For this reason, as shown in FIG. 4, when hammer peening is applied to an out-of-plane gusset joint in which the rib 2 is upright on the surface of the base material 1, a deep groove that causes stress concentration is formed at the toe 4 of the weld bead 3. There is a possibility that a fatigue crack is formed from the vicinity of the toe 4 of the weld bead 3.
従って、本発明は、上述した問題点に鑑みてなされたものであり、その目的は、鋼橋などの溶接構造物の溶接部に疲労き裂などの疲労損傷が発生することを確実に抑制することのできる溶接構造物の疲労損傷抑制方法、その方法に用いられる打撃痕形成用工具、および溶接構造物を提供することを目的とするものである。 Accordingly, the present invention has been made in view of the above-described problems, and the object thereof is to reliably suppress the occurrence of fatigue damage such as fatigue cracks in the welded portion of a welded structure such as a steel bridge. It is an object of the present invention to provide a method for suppressing fatigue damage of a welded structure, a tool for forming an impact mark used in the method, and a welded structure.
上記課題を解決するために、本発明のうち請求項１に係る溶接構造物の疲労損傷抑制方法は、溶接ビードと隣接する母材の表面に打撃痕形成用工具を用いて打撃痕を形成するハンマーピーニング又は超音波衝撃処理を施す、溶接構造物の疲労損傷抑制方法であって、前記打撃痕形成用工具として、平坦でかつ半径が１．５ｍｍ以上３．０ｍｍ以下の円形で形成された打撃痕形成面を先端に有する打撃痕形成用工具を用い、該打撃痕形成用工具により前記溶接ビードの止端より前記母材側に０．５ｍｍ離れた位置から３ｍｍまでの領域において、最大深さが０．１ｍｍ以上０．５０ｍｍ未満の打撃痕を前記溶接ビードに沿って連続的に形成することを特徴としている。
なお、円形で形成された打撃痕形成面の円形の定義として、長径／短径の比が、１〜１．１であれば、略円形として使用できる。長径の向きは、溶接線に対して特定しない。
In order to solve the above-mentioned problems, a fatigue damage suppression method for a welded structure according to claim 1 of the present invention forms a hitting mark on the surface of a base material adjacent to a weld bead using a hitting mark forming tool. A method for suppressing fatigue damage of a welded structure, which is subjected to hammer peening or ultrasonic impact treatment, wherein the hitting scar forming tool is flat and has a round shape with a radius of 1.5 mm to 3.0 mm. In a region from a position 0.5 mm away from the toe of the weld bead to 3 mm from the toe end of the weld bead by the tool for forming a hitting mark having a mark forming surface at the tip, the maximum depth is 3 mm. Is characterized in that striking traces of 0.1 mm or more and less than 0.50 mm are continuously formed along the weld bead.
In addition, if the ratio of the major axis / minor axis is 1 to 1.1 as the definition of the circular shape of the hitting mark forming surface formed in a circular shape, it can be used as a substantially circular shape. The direction of the major axis is not specified with respect to the weld line.
また、本発明のうち請求項２に係る溶接構造物の疲労損傷抑制方法は、請求項１記載の溶接構造物の疲労損傷抑制方法において、前記打撃痕形成用工具として、前記打撃痕形成面に対する垂直方向において傾斜する側面を有する円錐台形状に形成された打撃痕形成用工具を用いることを特徴としている。
更に、本発明のうち請求項３に係る溶接構造物の疲労損傷抑制方法は、請求項１又は２記載の溶接構造物の疲労損傷抑制方法において、前記打撃痕形成用工具として、前記打撃痕形成面の周囲に０．１５ｍｍ以上０．５０ｍｍ以下の曲率半径で円弧状に湾曲する面取り部を有する打撃痕形成用工具を用いることを特徴としている。
According to a second aspect of the present invention, there is provided a method for suppressing fatigue damage of a welded structure according to claim 1, wherein the method for suppressing fatigue damage of a welded structure according to claim 1 is applied as the tool for forming a hitting mark to the hitting mark forming surface. It is characterized by using a tool for forming an impact mark formed in a truncated cone shape having a side surface inclined in the vertical direction.
Furthermore, the fatigue damage suppression method for a welded structure according to claim 3 of the present invention is the fatigue damage suppression method for a welded structure according to claim 1 or 2, wherein the hitting trace formation is used as the hitting trace forming tool. It is characterized in that a tool for forming an impact mark having a chamfered portion that is curved in an arc shape with a radius of curvature of 0.15 mm or more and 0.50 mm or less is used around the surface.
また、本発明のうち請求項４に係る溶接構造物は、溶接ビードと隣接する母材の表面に打撃痕を形成した溶接構造物であって、前記打撃痕が、前記溶接ビードの止端より前記母材側に０．５ｍｍ離れた位置から３ｍｍまでの領域において、最大深さが０．１ｍｍ以上０．５０ｍｍ未満で形成されていることを特徴としている。 Moreover , the welding structure which concerns on Claim 4 among this invention is a welding structure which formed the hit | damage trace on the surface of the base material adjacent to a weld bead , Comprising : The said hit | damage trace is from the toe of the said weld bead. In the region from the position 0.5 mm away from the base material side to 3 mm , the maximum depth is 0.1 mm or more and less than 0.50 mm.
本発明によれば、溶接ビードの止端近傍に３００ＭＰａを越える圧縮残留応力を導入することが可能となるので、鋼橋などの溶接構造物の溶接部に疲労き裂などの疲労損傷が発生することを確実に抑制することができる。 According to the present invention, it is possible to introduce a compressive residual stress exceeding 300 MPa in the vicinity of the toe of the weld bead, so that fatigue damage such as a fatigue crack occurs in a welded portion of a welded structure such as a steel bridge. This can be reliably suppressed.
以下、本発明の実施の形態を図面を参照して説明する。図１は、本発明に係る溶接構造物の疲労損傷抑制方法を実施するときに用いられる打撃痕形成用工具の一例を示す斜視図である。図２は、図１に示す打撃痕形成用工具を示し、（ａ）は図１におけるＸＺ平面に沿って切断した断面図、（ｂ）は図１におけるＹＺ平面に沿って切断した断面図、（ｃ）は底面図である。 Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing an example of a tool for forming an impact mark used when the method for suppressing fatigue damage of a welded structure according to the present invention is performed. 2 shows the tool for forming a hitting mark shown in FIG. 1, (a) is a sectional view cut along the XZ plane in FIG. 1, (b) is a sectional view cut along the YZ plane in FIG. 1, (C) is a bottom view.
先ず、本発明を実施するときに用いられる打撃痕形成用工具６は、ＳＭ５７０等の高強度鋼から形成されているとともに、図１及び図２に示すように、先端に打撃痕形成面７を形成している。この打撃痕形成面７は、溶接ビード３（図４参照）と隣接する母材１の表面に打撃痕５を形成するためのものである。打撃痕形成面７は、図２に示すように、平坦でかつ半径が１．５ｍｍ以上３．０ｍｍ以下、即ち直径Ｄが３．０ｍｍ以上６．０ｍｍ以下の円形で形成されている。 First, the hitting trace forming tool 6 used when practicing the present invention is made of high-strength steel such as SM570, and as shown in FIGS. Forming. The hitting mark forming surface 7 is for forming the hitting marks 5 on the surface of the base material 1 adjacent to the weld bead 3 (see FIG. 4). As shown in FIG. 2, the hitting mark forming surface 7 is flat and has a radius of 1.5 mm to 3.0 mm, that is, a circle having a diameter D of 3.0 mm to 6.0 mm.
このように、打撃痕形成用工具６の先端に形成された打撃痕形成面７を平坦としたのは、平坦でないと、母材１側に形成された打撃痕５の深さ及び幅（打撃痕形成用工具７の移動方向である図４において紙面に対して直交する方向に直交する方向の長さ）にばらつきを生じるからである。また、打撃痕形成面７を半径が１．５ｍｍ以上３．０ｍｍ以下の円形としたのは、半径が１．０ｍｍ未満の場合には、形成された打撃痕５の深さ及び幅にばらつきが生じ、形状が安定して得られない。一方、半径が３．０ｍｍより大きい場合には、打撃痕形成面７の面積が大きくなるため、母材１に対して十分な深さの打撃痕５を形成することができなくなり、溶接ビード３の止端４の近傍への圧縮残留応力導入による疲労強度向上効果が小さくなるからである。 In this way, if the hitting mark forming surface 7 formed at the tip of the hitting mark forming tool 6 is not flat, the depth and width of the hitting mark 5 formed on the base material 1 side (the hitting) This is because variations occur in the length of the direction perpendicular to the paper surface in FIG. Further, the reason that the hitting mark forming surface 7 is a circle having a radius of 1.5 mm or more and 3.0 mm or less is that when the radius is less than 1.0 mm, the depth and width of the formed hitting mark 5 vary. The shape is not obtained stably. On the other hand, when the radius is larger than 3.0 mm, the area of the hitting mark forming surface 7 becomes large, so that the hitting mark 5 having a sufficient depth cannot be formed with respect to the base material 1, and the weld bead 3. This is because the effect of improving the fatigue strength due to the introduction of compressive residual stress in the vicinity of the toe 4 is reduced.
また、打撃痕形成用工具６は、図２に示すように、打撃痕形成面７に対する垂直方向において傾斜する側面を有する円錐台形状に形成されている。このように、打撃痕形成用工具６を円錐台形状とすることにより、度重なる打撃によっても工具の形状を保ちやすいという効果を奏する。
更に、打撃痕形成用工具６としては、図２に示す形状に限らず、図３に示すように、打撃痕形成面７に対する垂直方向において傾斜する側面を有する円錐台形状に形成されるとともに、打撃痕形成面７の周囲に０．１５ｍｍ以上０．５０ｍｍ以下の曲率半径ｒＯで円弧状に湾曲する面取り部８を形成したものを用いてもよい。
Further, as shown in FIG. 2, the hitting trace forming tool 6 is formed in a truncated cone shape having a side surface that is inclined in a direction perpendicular to the hitting trace forming surface 7. In this way, by forming the hitting trace forming tool 6 in the shape of a truncated cone, there is an effect that it is easy to maintain the shape of the tool even by repeated hitting.
Further, the hitting trace forming tool 6 is not limited to the shape shown in FIG. 2, and as shown in FIG. 3, the hitting trace forming tool 6 is formed in a truncated cone shape having a side surface inclined in a direction perpendicular to the hitting trace forming surface 7. may be used in which the formation of the chamfered portion 8 curved in an arc shape with a radius of curvature r O of 0.15mm or 0.50mm or less around the striking trace formed surface 7.
ここで、面取り部８の曲率半径ｒＯを０．１５ｍｍ以上０．５０ｍｍ以下とした理由は以下の理由からである。すなわち面取り部８の曲率半径ｒＯが０．１５ｍｍ未満では、打撃痕５の底の端部に応力が集中しやすい状態になるからである。また、面取り部８の曲率半径ｒＯが０．５０ｍｍを超えると母材１の表面に接触する打撃痕形成面７の接触面積が大きくなるため、母材１に対して十分な深さの打撃痕５を形成することができなくなり、溶接ビード３の止端４の近傍への圧縮残留応力導入による疲労強度向上効果が小さくなるからである。 The reason why the curvature radius r O in the chamfer 8 was 0.15mm or 0.50mm or less because of the following reasons. That is, when the radius of curvature r O of the chamfered portion 8 is less than 0.15 mm, stress tends to concentrate on the bottom end of the hitting mark 5. Further, if the radius of curvature r O of the chamfered portion 8 exceeds 0.50 mm, the contact area of the hitting mark forming surface 7 that comes into contact with the surface of the base material 1 becomes large, so that the base material 1 is hit with a sufficient depth. This is because the trace 5 cannot be formed, and the effect of improving the fatigue strength by introducing the compressive residual stress in the vicinity of the toe 4 of the weld bead 3 is reduced.
このような打撃痕形成用工具６を用いて本発明を実施する際には、図４において、溶接ビード３と隣接する母材１の表面に、打撃痕形成用工具６を垂直に押し当てて打撃し、打撃痕形成用工具６を溶接線方向（図４における紙面に対して直交する方向、図１における矢印Ｙ方向）に相対的に移動させ、前記打撃痕形成用工具６による打撃と前記打撃痕形成用工具６の移動を繰り返して当該表面に打撃痕５を形成するハンマーピーニング又は超音波衝撃処理を施す。
つまり、打撃痕形成面７が溶接ビード３の止端４と隣接するように打撃痕形成用工具６の位置を調整した後、打撃痕形成用工具６の打撃痕形成面７を母材１の表面に垂直に押し当てて打撃し、溶接ビード３の止端４より母材１側に５ｍｍまでの領域において、最大深さが０．０３ｍｍ以上０．５０ｍｍ未満の打撃痕５を形成する。
When carrying out the present invention using such a hitting trace forming tool 6, the hitting trace forming tool 6 is pressed vertically against the surface of the base material 1 adjacent to the weld bead 3 in FIG. 4. The hammer 6 is moved relative to the welding line direction (the direction perpendicular to the paper surface in FIG. 4, the direction of the arrow Y in FIG. 1). Hammer peening or ultrasonic impact treatment for forming the hitting marks 5 on the surface by repeating the movement of the hitting mark forming tool 6 is performed.
That is, after adjusting the position of the striking trace forming tool 6 so that the striking trace forming surface 7 is adjacent to the toe 4 of the weld bead 3, the striking trace forming surface 7 of the striking trace forming tool 6 is used as the base material 1. A hitting mark 5 having a maximum depth of 0.03 mm or more and less than 0.50 mm is formed in a region of 5 mm from the toe 4 of the weld bead 3 to the base metal 1 side by hitting the surface perpendicularly to the surface.
次に、打撃痕形成用工具６の打撃痕形成面７を母材１の表面から引き離した後、打撃痕形成用工具６を溶接ビード３の溶接線方向に所定距離だけ移動させる。そして、再び打撃痕形成用工具６の打撃痕形成面７を母材１の表面に垂直に押し当てて打撃し、母材１の表面に打撃痕５を形成し、この打撃痕形成用工具６による打撃と打撃痕形成用工具６の移動とを繰り返して、複数の打撃痕５を溶接ビード３に沿って連続的に形成する。
これにより、複数の打撃痕５が、溶接ビード３の止端部４より母材１側に５ｍｍまでの領域において、最大深さが０．０３ｍｍ以上０．５０ｍｍ未満で形成された溶接構造物が得られる。
ここで、打撃痕５が、溶接ビード３の止端４より母材１側に５ｍｍまでの領域において、最大深さが０．０３ｍｍ以上０．５０ｍｍ未満で形成することとしたのは、次の理由による。打撃痕５の最大深さが溶接ビード３の止端４より母材１側に５ｍｍを超えて形成されると、止端近傍に圧縮残留応力が十分に導入されないからである。
Next, after the striking trace forming surface 7 of the striking trace forming tool 6 is separated from the surface of the base material 1, the striking trace forming tool 6 is moved by a predetermined distance in the weld line direction of the weld bead 3. Then, the striking trace forming surface 7 of the striking trace forming tool 6 is again pressed against the surface of the base material 1 for impact, and the striking trace 5 is formed on the surface of the base material 1. A plurality of hitting marks 5 are continuously formed along the weld bead 3 by repeating the hitting and the movement of the hitting mark forming tool 6.
As a result, a welded structure in which a plurality of hitting marks 5 are formed with a maximum depth of 0.03 mm or more and less than 0.50 mm in a region up to 5 mm on the base material 1 side from the toe end 4 of the weld bead 3. can get.
Here, in the area | region to 5 mm in the base material 1 side from the toe 4 of the weld bead 3, the hit | damage trace 5 decided to form with the maximum depth 0.03 mm or more and less than 0.50 mm. Depending on the reason. This is because if the maximum depth of the hitting mark 5 is more than 5 mm closer to the base material 1 than the toe 4 of the weld bead 3, the compressive residual stress is not sufficiently introduced in the vicinity of the toe.
また、打撃痕５の最大深さが０．０３ｍｍ以上０．５０ｍｍ未満でとしたのは、打撃痕５の最大深さが０．０３ｍｍよりも浅いと止端近傍に圧縮残留応力が十分に導入されないからであり、０．５０ｍｍ以上であると、引張負荷時に打撃痕底部に応力が集中し、疲労き裂発生の起点となるからである。
なお、打撃痕５が、溶接ビード３の止端４より母材１側に０．５ｍｍ離れた位置から３ｍｍまでの領域において、最大深さが０．１ｍｍ以上０．５０ｍｍ未満で形成されていると一層好ましい。この理由は、止端近傍への圧縮残留応力の導入が十分になされるからである。
Also, the maximum depth of the hitting mark 5 is 0.03 mm or more and less than 0.50 mm. If the maximum depth of the hitting mark 5 is shallower than 0.03 mm, sufficient compressive residual stress is introduced near the toe. This is because if the thickness is 0.50 mm or more, stress concentrates on the bottom of the impact mark at the time of a tensile load, which becomes a starting point of fatigue crack generation.
The hitting marks 5 are formed with a maximum depth of 0.1 mm or more and less than 0.50 mm in a region from a position 0.5 mm away from the toe 4 of the weld bead 3 to the base material 1 side to 3 mm. And more preferable. This is because the compressive residual stress is sufficiently introduced in the vicinity of the toe.
本発明者らは、表１（実施例１〜８、比較例１〜６）に示す先端形状を有する打撃痕形成用工具を用いて、１２ｍｍ厚×１００ｍｍ×３００ｍｍの鋼板にハンマーピーニング（空気圧：約０．５８８ＭＰａ（約６ｋｇ／ｃｍ２）、周波数：９０Ｈｚ、移動速度：０．２５ｍｍ／秒による）で溶接線に沿って１００ｍｍの長さにわたって溶接ビードの止端より母材側に５ｍｍまでの領域において打撃痕の最大深さが０．０２ｍｍ〜０．５０ｍｍとなるように打撃痕形成用工具を垂直に繰り返し打撃した後、打撃痕５の端部（止端４側の端部）から１ｍｍ離れた位置の残留応力をＸ線により測定した。Ｘ線を用いた残留応力測定は、ビーム径１ｍｍφで行った。試験結果を表１に示す。 The present inventors used hammer peening (air pressure: air pressure) to a steel plate of 12 mm thickness × 100 mm × 300 mm using a tool for forming an impact mark shown in Table 1 (Examples 1-8, Comparative Examples 1-6). About 0.588 MPa (about 6 kg / cm 2 ), frequency: 90 Hz, moving speed: according to 0.25 mm / second) over a length of 100 mm along the weld line up to 5 mm from the toe of the weld bead to the base metal side After repeatedly hitting the tool for forming a hitting mark vertically so that the maximum depth of the hitting mark becomes 0.02 mm to 0.50 mm in the region, 1 mm from the end of the hitting mark 5 (end on the toe 4 side) The residual stress at a remote location was measured by X-ray. Residual stress measurement using X-rays was performed with a beam diameter of 1 mmφ. The test results are shown in Table 1.
表１の実施例１〜４は、溶接ビード３と隣接する母材１の表面に、溶接ビード３の止端４より母材側に５ｍｍまでの領域において最大深さが０．０３ｍｍ以上０．５０ｍｍ未満の打撃痕５を打撃痕形成面７の直径Ｄが３ｍｍ、４ｍｍ、５ｍｍ、６ｍｍの打撃痕形成用工具６により溶接ビード３に沿って連続的に形成した場合を示している。
また、表１の実施例５〜８は、溶接ビード３と隣接する母材１の表面に、溶接ビード３の止端４より母材側に５ｍｍまでの領域において最大深さが０．０３ｍｍ以上０．５０ｍｍ未満の打撃痕５を打撃痕形成面７の直径Ｄが３ｍｍ、４ｍｍ、５ｍｍ、６ｍｍ、面取り部８の曲率半径ｒＯが０．１５ｍｍ、０．２０ｍｍ、０．５０ｍｍの打撃痕形成用工具６により溶接ビード３に沿って連続的に形成した形成した場合を示している。
In Examples 1 to 4 of Table 1, the maximum depth is 0.03 mm or more in the region of 5 mm from the toe 4 of the weld bead 3 to the base metal side on the surface of the base metal 1 adjacent to the weld bead 3. The case is shown in which the hitting marks 5 of less than 50 mm are continuously formed along the weld bead 3 by the hitting mark forming tool 6 having a diameter D of the hitting mark forming surface 7 of 3 mm, 4 mm, 5 mm, and 6 mm.
Further, in Examples 5 to 8 in Table 1, the maximum depth is 0.03 mm or more in the region up to 5 mm from the toe 4 of the weld bead 3 to the surface of the base material 1 adjacent to the weld bead 3. Stroke marks 5 having a diameter D of 3 mm, 4 mm, 5 mm, and 6 mm and a radius of curvature r O of the chamfered portion 8 of 0.15 mm, 0.20 mm, and 0.50 mm are formed. The case where it formed continuously along the weld bead 3 with the work tool 6 is shown.
一方、表１の比較例１〜３は図６に示す打撃痕形成用工具１０の先端に円形（直径Ｄ：２ｍｍ、３ｍｍ、４ｍｍ）の打撃痕形成面１１が球面状（曲率半径ｒ：１．５ｍｍ、２ｍｍ、４ｍｍ）に形成されたものを用いて打撃痕５を溶接ビード３と隣接する母材１の表面に形成した場合を示し、比較例４、５は図７に示す打撃痕形成用工具１２の先端に正方形（1辺の長さＬ：３ｍｍ、５ｍｍ）の打撃痕形成面１３が平面状に形成されたものを用いて打撃痕５を溶接ビード３と隣接する母材１の表面に形成した場合を示している。また、比較例６は、打撃痕形成面７の直径Ｄが６ｍｍであるものの、打撃痕の最大深さが０．０３ｍｍ未満のものを示す。
なお、表１のＲａは打撃痕５の最大深さを示すものである。
On the other hand, in Comparative Examples 1 to 3 of Table 1, a round (diameter D: 2 mm, 3 mm, 4 mm) hitting mark forming surface 11 is spherical (curvature radius r: 1) at the tip of the hitting mark forming tool 10 shown in FIG. 5 mm, 2 mm, and 4 mm) are used to show the impact mark 5 formed on the surface of the base material 1 adjacent to the weld bead 3, and Comparative Examples 4 and 5 show the impact mark formation shown in FIG. Using the tool 12 having a square (1 side length L: 3 mm, 5 mm) striking trace forming surface 13 formed in a flat shape, the striking trace 5 is formed on the base material 1 adjacent to the weld bead 3. The case where it forms on the surface is shown. Comparative Example 6 shows a case where the maximum depth of the hitting trace is less than 0.03 mm, although the diameter D of the hitting trace forming surface 7 is 6 mm.
In Table 1, Ra represents the maximum depth of the hitting mark 5.
実施例１〜８と比較例１〜６を比較すると、比較例１〜６では打撃痕５により溶接ビード３の止端４の近傍に導入される圧縮残留応力が６０ＭＰａ〜２７０ＭＰａであるのに対し、実施例１〜８では打撃痕５により溶接ビード３の止端４の近傍に導入される圧縮残留応力が３００ＭＰａ〜３３０ＭＰａとなることがわかる。
したがって、実施例１〜８のように、打撃痕形成用工具６として、平坦でかつ半径が１．５ｍｍ以上３．０ｍｍ以下の円形で形成された打撃痕形成面７を先端に有する打撃痕形成用工具６を用い、打撃痕形成用工具６により溶接ビード３の止端４より母材１側に５ｍｍまでの領域において、最大深さが０．０３ｍｍ以上０．５０ｍｍ未満の打撃痕５を溶接ビード３に沿って連続的に形成することで、溶接ビード３の止端４の近傍に３００ＭＰａを超える圧縮残留応力を導入することが可能となるので、鋼橋などの溶接構造物の溶接部に疲労き裂などの疲労損傷が発生することを確実に抑制することができる。
When Examples 1-8 are compared with Comparative Examples 1-6, in Comparative Examples 1-6, the compressive residual stress introduced in the vicinity of the toe 4 of the weld bead 3 by the hitting marks 5 is 60 MPa to 270 MPa. In Examples 1 to 8, it can be seen that the compressive residual stress introduced in the vicinity of the toe 4 of the weld bead 3 by the hitting marks 5 is 300 MPa to 330 MPa.
Therefore, as in Examples 1 to 8, as the hitting trace forming tool 6, hitting trace forming having a hitting trace forming surface 7 which is flat and has a radius of 1.5 mm or more and 3.0 mm or less at the tip. The tool 6 for welding is used to weld the impact mark 5 having a maximum depth of 0.03 mm or more and less than 0.50 mm in the region from the toe 4 of the weld bead 3 to the base material 1 side by the impact mark forming tool 6 up to 5 mm. By continuously forming along the bead 3, it becomes possible to introduce a compressive residual stress exceeding 300 MPa in the vicinity of the toe 4 of the weld bead 3. The occurrence of fatigue damage such as fatigue cracks can be reliably suppressed.
また、実施例５〜８のように、打撃痕形成用工具６として、打撃痕形成面７の周囲に０．１５ｍｍ以上０．５０ｍｍ以下の曲率半径で円弧状に湾曲する面取り部８を有する打撃痕形成用工具６を用いることで、打撃痕５の周囲に応力集中が発生することを防止することができる。
また、本発明者らは、図５に示す溶接継手を溶接電流：２８０Ａ、溶接電圧：３２Ｖ、溶接速度：２８ｃｐｍの溶接条件にて試験片として作製し、打撃痕形成面の形状が矩形（３×４ｍｍ）の打撃痕形成用工具及び打撃痕形成面の形状が円形（半径１．５ｍｍ、直径３．０ｍｍ）の打撃痕形成用工具をそれぞれ用いて、ハンマーピーニング（空気圧：約０．５８８ＭＰａ（約６ｋｇ／ｃｍ２）、周波数：９０Ｈｚ、移動速度：０．２５ｍｍ／秒による）で打撃痕形成用工具を垂直に繰り返し打撃した。図８に、打撃痕形成面の形状が矩形の打撃痕形成用工具を用いて母材表面に打撃痕を形成した場合と打撃痕形成面の形状が円形の打撃痕形成用工具を用いて母材表面に打撃痕を形成した場合とを比較して示す写真を示す。
Further, as in Examples 5 to 8, as the hitting trace forming tool 6, the hitting having the chamfered portion 8 curved in an arc shape with a radius of curvature of 0.15 mm or more and 0.50 mm or less around the hitting trace forming surface 7. By using the trace forming tool 6, it is possible to prevent stress concentration from occurring around the hitting trace 5.
In addition, the present inventors made the weld joint shown in FIG. 5 as a test piece under the welding conditions of welding current: 280 A, welding voltage: 32 V, welding speed: 28 cpm, and the shape of the impact mark formation surface is rectangular (3 × 4 mm) hammer peening (pneumatic pressure: about 0.588 MPa (air pressure: about 0.588 MPa) using a tool for forming an impact mark and a tool for forming an impact mark having a circular shape (radius 1.5 mm, diameter 3.0 mm). The striking trace forming tool was repeatedly struck vertically at a frequency of about 6 kg / cm 2 ), frequency: 90 Hz, and moving speed: 0.25 mm / sec. FIG. 8 shows a case in which a striking trace is formed on the surface of the base material using a striking trace forming tool having a rectangular striking mark formation surface and a striking mark forming surface having a circular shape. The photograph shown in comparison with the case where an impact mark is formed on the material surface is shown.
その結果、打撃痕形成面の形状が矩形（３×４ｍｍ）の打撃痕形成用工具を用いて母材表面に打撃痕を形成した場合は、図８（ｂ）に示すように、溶接止端の線と打撃痕の端線との間に１．８ｍｍの隙間が発生した。これに対し、打撃痕形成面の形状が円形（半径：１．５ｍｍ、直径３．０ｍｍ）で平面状の打撃痕形成用工具を用いて母材表面に打撃痕を形成した場合は、図８（ａ）に示すように、溶接止端の線と打撃痕の端線との間に隙間は見られず、溶接止端の線と打撃痕の端線との間に隙間を発生させることなく止端より母材側に０．５ｍｍ〜３ｍｍまでの領域において打撃痕を形成できることを確認できた。 As a result, when a hitting mark is formed on the base material surface using a hitting mark forming tool having a rectangular (3 × 4 mm) hitting mark forming surface, as shown in FIG. A gap of 1.8 mm was generated between this line and the end line of the hit mark. On the other hand, when the shape of the hitting mark forming surface is circular (radius: 1.5 mm, diameter 3.0 mm) and the hitting mark is formed on the base material surface using a flat hitting mark forming tool, FIG. As shown to (a), a clearance gap is not seen between the line of a welding toe and the end line of a hitting mark, but without generating a gap between the line of a welding toe and the end line of a hitting mark It was confirmed that a hitting mark could be formed in a region from 0.5 mm to 3 mm on the base material side from the toe.
１…母材
２…リブ
３…溶接ビード
４…止端
５…打撃痕
６，１０，１２…打撃痕形成用工具
７，１１，１３…打撃痕形成面
８…面取り部
DESCRIPTION OF SYMBOLS 1 ... Base material 2 ... Rib 3 ... Weld bead 4 ... Stop end 5 ... Blowing trace 6, 10, 12 ... Blowing trace formation tool 7, 11, 13 ... Blowing trace formation surface 8 ... Chamfering part
Claims (4)
前記打撃痕形成用工具として、平坦でかつ半径が１．５ｍｍ以上３．０ｍｍ以下の円形で形成された打撃痕形成面を先端に有する打撃痕形成用工具を用い、該打撃痕形成用工具により前記溶接ビードの止端より前記母材側に０．５ｍｍ離れた位置から３ｍｍまでの領域において、最大深さが０．１ｍｍ以上０．５０ｍｍ未満の打撃痕を前記溶接ビードに沿って連続的に形成することを特徴とする溶接構造物の疲労損傷抑制方法。 A method for suppressing fatigue damage of a welded structure, in which hammer peening or ultrasonic impact treatment is performed on a surface of a base material adjacent to a weld bead by using a hammer mark forming tool to form a hammer mark,
As the hitting mark forming tool, a hitting mark forming tool having a hitting mark forming surface that is flat and formed in a circle having a radius of 1.5 mm or more and 3.0 mm or less at the tip is used. In a region from a position 0.5 mm away from the toe of the weld bead to the base material side to 3 mm , a maximum hit depth of 0.1 mm or more and less than 0.50 mm is continuously formed along the weld bead. A method for suppressing fatigue damage of a welded structure, characterized by comprising:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2012261047A JP6051817B2 (en) | 2011-11-29 | 2012-11-29 | Method for suppressing fatigue damage of welded structure, tool for forming impact mark used in the method, and welded structure |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2011260545 | 2011-11-29 | ||
| JP2011260545 | 2011-11-29 | ||
| JP2012261047A JP6051817B2 (en) | 2011-11-29 | 2012-11-29 | Method for suppressing fatigue damage of welded structure, tool for forming impact mark used in the method, and welded structure |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2013136093A JP2013136093A (en) | 2013-07-11 |
| JP6051817B2 true JP6051817B2 (en) | 2016-12-27 |
Family
ID=48912298
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2012261047A Active JP6051817B2 (en) | 2011-11-29 | 2012-11-29 | Method for suppressing fatigue damage of welded structure, tool for forming impact mark used in the method, and welded structure |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP6051817B2 (en) |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102007036972A1 (en) * | 2007-08-04 | 2009-02-05 | Mtu Aero Engines Gmbh | Method for joining and joining connection of two components made of metal material |
| JP4987816B2 (en) * | 2008-07-28 | 2012-07-25 | 新日本製鐵株式会社 | Automatic impact processing method and automatic impact processing apparatus for improving the fatigue characteristics of welded joints |
| JP4441641B1 (en) * | 2008-11-25 | 2010-03-31 | 国立大学法人名古屋大学 | Fatigue crack repair method for steel structures |
| JP4751484B1 (en) * | 2010-01-28 | 2011-08-17 | 新日本製鐵株式会社 | Fatigue property improving impact treatment apparatus for welded joint, fatigue property improving method, and method for manufacturing welded joint with improved fatigue property |
-
2012
- 2012-11-29 JP JP2012261047A patent/JP6051817B2/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| JP2013136093A (en) | 2013-07-11 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| TWI396600B (en) | Out-of-plane gusset weld joints and manufacturing method therefor | |
| JP2014014831A (en) | Fatigue strength improving method of weld zone and welded joint | |
| JP2011131260A (en) | Method for increasing fatigue strength of weld zone, and weld joint | |
| KR101577261B1 (en) | Method for preventing fatigue damage in welded structures, tool for forming impact area, and welded structure | |
| JP5844551B2 (en) | Manufacturing method of welded joint | |
| JP5251486B2 (en) | Machining method using ultrasonic impact treatment | |
| JP4837428B2 (en) | Ultrasonic impact treatment method for weld toe | |
| JP6495569B2 (en) | Tool for forming impact marks | |
| JP4895407B2 (en) | Peening method and welded joint using it | |
| JP2013071140A (en) | Welded joint excellent in fatigue resistance and method for manufacturing the same | |
| JP5977077B2 (en) | Welding peening method | |
| JP5919986B2 (en) | Hammer peening treatment method and welded joint manufacturing method using the same | |
| JP2013233590A (en) | Welded joint superior in fatigue characteristic | |
| JP6051817B2 (en) | Method for suppressing fatigue damage of welded structure, tool for forming impact mark used in the method, and welded structure | |
| JP5898498B2 (en) | Method for improving fatigue strength of welded part and welded joint | |
| JP5327567B1 (en) | Peening method and welded joint | |
| JP2013136094A (en) | Weld structure of steel | |
| JP6017938B2 (en) | Method for suppressing fatigue damage of welded structure and tool for forming hitting marks | |
| JP5955752B2 (en) | Method for suppressing fatigue damage of welded structure and tool for forming hitting marks | |
| JP6339760B2 (en) | Method for suppressing fatigue damage of welded structure and tool for forming hitting marks | |
| JP5252112B1 (en) | Peening construction method | |
| JP5599652B2 (en) | Welded joint | |
| JP6747416B2 (en) | Tool for forming impact mark and method for producing welded joint | |
| WO2012164774A1 (en) | Welded joint | |
| JP6696604B1 (en) | Needle peening method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20150825 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20160517 |
|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20160518 |
|
| A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20160706 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20161101 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20161114 |
|
| R150 | Certificate of patent or registration of utility model |
Ref document number: 6051817 Country of ref document: JP Free format text: JAPANESE INTERMEDIATE CODE: R150 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |