JP4262018B2 - Structure building member and manufacturing method thereof - Google Patents

Structure building member and manufacturing method thereof Download PDF

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JP4262018B2
JP4262018B2 JP2003271260A JP2003271260A JP4262018B2 JP 4262018 B2 JP4262018 B2 JP 4262018B2 JP 2003271260 A JP2003271260 A JP 2003271260A JP 2003271260 A JP2003271260 A JP 2003271260A JP 4262018 B2 JP4262018 B2 JP 4262018B2
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welding
covering
steel
plate
stainless steel
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JP2004131843A (en
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之郎 釣
正次 村瀬
千昭 加藤
最仁 藤原
昆 王
喜有 中尾
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JFE Steel Corp
JFE Engineering Corp
Nippon Yakin Kogyo Co Ltd
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Nippon Yakin Kogyo Co Ltd
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本発明は、構造物構築部材、詳しくは海洋構造物の海中部、干満帯、飛沫帯および海上部に適用されて長期にわたり優れた防食性を維持できる防食性に優れた構造物構築部材、およびその製造方法に関する。   The present invention is a structure building member, particularly a structure building member with excellent anticorrosion properties that can be applied to the mid-sea, tidal zone, splash zone, and upper sea of marine structures to maintain excellent anti-corrosion properties over a long period of time, and It relates to the manufacturing method.

海洋空間を有効利用するため様々な海洋構造物が開発されてきた。近年は環境調和の観点から、従来の埋め立て工法に対して海洋ジャケット構造物を用いた工法が注目されつつある。このような海洋構造物には鋼管や鋼管杭等が用いられるが、実際の腐食環境が極めて厳しいため、何らかの防食対策が必須となる。特に大型の鋼構造物の場合には、すべての腐食箇所を適宜見つけ出して補修し、長年に亘って維持・管理するには膨大なコストが必要となる。したがってライフサイクルコストの観点からすれば、初期投資がやや高額になっても、可及的平易な管理方法で長期の耐食性維持を可能にする防食工法を適用することが、長い目で見た場合のトータルコスト低減につながるので有利である。   Various marine structures have been developed to make effective use of marine space. In recent years, from the viewpoint of environmental harmony, a construction method using a marine jacket structure has been attracting attention compared to a conventional landfill construction method. Steel pipes, steel pipe piles, and the like are used for such offshore structures, but some anticorrosion measures are essential because the actual corrosive environment is extremely severe. In particular, in the case of large steel structures, enormous costs are required to find and repair all corroded areas as appropriate, and to maintain and manage them for many years. Therefore, from the viewpoint of life cycle cost, it is necessary to apply a corrosion prevention method that allows long-term corrosion resistance to be maintained with the simplest possible management method even if the initial investment becomes slightly high. This is advantageous because it leads to a total cost reduction.

海洋構造物における鋼材の防食方法は、当該鋼材の適用部位によって適否が大きく異なる。例えば、海中部（常に海水中に漬かっている部位）の防食は電気防食によってなされることが多い。すなわち、Al合金系の犠牲陽極の取付けあるいは外部からの電流供給により、鋼材表面の電位を本来の腐食電位よりも卑な方向にシフトさせ、鉄の溶解反応を抑制する防食方法である。この方法は海中部に対しては低コストで容易かつ確実に防食できるため極めて優れた方法であるが、常に鋼材表面に防食電流が流れていないと防食効果を発揮しえないため、干満帯〜海上部に対して用いても効果に乏しい。   The suitability of a steel material corrosion prevention method in an offshore structure varies greatly depending on the application site of the steel material. For example, anticorrosion in the sea (parts that are always immersed in seawater) is often made by electrocorrosion. In other words, this is an anticorrosion method that suppresses the dissolution reaction of iron by shifting the potential of the steel surface in a base direction relative to the original corrosion potential by attaching an Al alloy-based sacrificial anode or supplying an electric current from the outside. This method is extremely excellent because it can be easily and surely protected against corrosion at low cost in the sea, but the anticorrosion effect cannot be exhibited unless the corrosion protection current always flows on the steel surface. Even if used on the sea, it is not effective.

そこで、従来の技術では、電気防食技術と塗覆装技術を併用することにより鋼材の海中部から海上部までの防食を行っている。塗覆装技術としては塗装や重防食が適用されているが、所謂防食寿命は塗装で10年程度、重防食で20〜30年程度であり、大型の鋼構造物の長期に亘る防食を考えるとその防食寿命は必ずしも十分ではない。   Therefore, in the conventional technique, corrosion prevention is performed from the underwater part of the steel material to the upper part of the sea by using both the anticorrosion technique and the coating technique. Painting and heavy anti-corrosion are applied as coating technology, but the so-called anti-corrosion life is about 10 years for painting and about 20 to 30 years for heavy anti-corrosion. Consider long-term corrosion prevention for large steel structures. And its anti-corrosion life is not always enough.

近年、これらの問題を克服するため、耐食性に優れる金属で鋼構造物の表面をライニングする手法が提案されている（例えば特許文献１、特許文献２、特許文献３参照）。
特開平11−179552号公報 特開平11−129090号公報 特開平2000−280068号公報 In recent years, in order to overcome these problems, a method of lining the surface of a steel structure with a metal having excellent corrosion resistance has been proposed (see, for example, Patent Document 1, Patent Document 2, and Patent Document 3).
Japanese Patent Laid-Open No. 11-179552 JP-A-11-129090 Japanese Unexamined Patent Publication No. 2000-280068

しかしながら、特許文献１所載の技術では、耐食金属板をインダイレクトシーム溶接で鋼材表面に固定するものであるため、耐食金属板同士の重なり部が不可避的に隙間構造となり、耐食金属板として同公報第〔0012〕欄に記載されているような各種ステンレス鋼板を用いた場合、隙間腐食が発生するという問題がある。   However, in the technique described in Patent Document 1, since the corrosion-resistant metal plates are fixed to the steel surface by indirect seam welding, the overlapping portions of the corrosion-resistant metal plates inevitably have a gap structure, which is the same as the corrosion-resistant metal plate. There is a problem that crevice corrosion occurs when various stainless steel plates as described in the publication [0012] column are used.

また、特許文献２所載の技術は、薄金属シートと厚金属基材表面との抵抗溶接による固相接合部をアーク溶接で溶融接合する技術であり、この溶融接合部は良好な機械的性質を有するものの、その実施例で薄金属シートとして用いられているSUS316は海洋生物が付着した際の隙間腐食に対する耐性に乏しいため長期の耐用は期待できないばかりか、一旦抵抗シーム溶接した箇所をさらにアーク溶接で溶融接合することから、アーク溶接時の過大な入熱量により溶接部およびその周囲の熱影響部の長期耐食性が著しく劣化する危険性がある。すなわち、アーク溶接時の過大な入熱量のため、スパッタの付着や表面酸化スケールの形成によって耐食性が低下するだけでなく、溶接ビード部周囲の溶接熱影響部において、クロムカーバイドが析出して粒界にクロム欠乏層が形成され、耐食性が著しく低下するのである。また、アーク溶接の際に使用する溶接棒組成について何ら考慮していないため、溶接ビート部の耐食性金属成分が希釈され、特に鋼材と接合した場合に、耐食性が低下する。   The technique described in Patent Document 2 is a technique in which a solid-phase joint by resistance welding between a thin metal sheet and a surface of a thick metal base material is melt-joined by arc welding, and this melt-joint has good mechanical properties. However, SUS316 used as a thin metal sheet in this example has poor resistance to crevice corrosion when marine organisms adhere to it, so long-term durability cannot be expected. Since fusion bonding is performed by welding, there is a risk that the long-term corrosion resistance of the welded part and the surrounding heat-affected part may be significantly deteriorated due to an excessive heat input during arc welding. That is, due to the excessive heat input during arc welding, not only does corrosion resistance decrease due to spatter adhesion or the formation of surface oxide scale, but chromium carbide precipitates in the weld heat affected zone around the weld bead, causing grain boundaries. Thus, a chromium-deficient layer is formed, and the corrosion resistance is remarkably lowered. In addition, since no consideration is given to the composition of the welding rod used in arc welding, the corrosion resistance metal component of the weld beat portion is diluted, and particularly when bonded to a steel material, the corrosion resistance decreases.

一方、特許文献３所載の技術は、薄板状のチタン材を抵抗溶接にて鋼構造物の表面に接合し、さらに前記チタン材同士の重ね継ぎ手部を溶融溶接することにより、長期の防食性を付与する技術である。一般に、鋼材とチタンは極めて脆い金属間化合物を形成するため、機械的強度、耐疲労性および耐食性の観点から長期の耐久性を有する溶融接合部を得ることが極めて困難であることは広く知られている。一方、鋼材の表面に耐食性金属をラインニングする防食方法においては、鋼材表面を耐食性金属で完全に密封し腐食因子を遮断することが肝要である。特許文献３所載の技術は、前記金属間化合物を形成することなく鋼材表面を完全に密封する技術として、エポキシ樹脂等でチタンライニング材と鋼構造物の間の隙間をシールすることを提唱している。しかしながら、チタン表面は酸化チタンを主体とした極めて不活性な不動態被膜で完全に覆われているため樹脂の付着性が極めて悪く、湿度の高い海洋環境で長期間に渡ってチタンラインニング材と鋼構造物の隙間を完全に密封することは期待できない。また、エポキシ樹脂は金属と比較して十分な耐衝撃性を有しないため、台風等により漂流物がこのシール部に激突した際にエポキシ樹脂の割れや剥落によってシールが破られる可能性がある。   On the other hand, the technique described in Patent Document 3 is a long-term anticorrosive property by joining a thin plate-like titanium material to the surface of a steel structure by resistance welding, and further melt-welding the lap joint portion between the titanium materials. Is a technology that gives In general, steel and titanium form extremely brittle intermetallic compounds, and it is widely known that it is extremely difficult to obtain a melt-bonded portion having long-term durability from the viewpoint of mechanical strength, fatigue resistance, and corrosion resistance. ing. On the other hand, in the anticorrosion method in which a corrosion-resistant metal is lined on the surface of the steel material, it is important to completely seal the steel material surface with the corrosion-resistant metal and block the corrosion factor. The technique described in Patent Document 3 proposes sealing the gap between the titanium lining material and the steel structure with an epoxy resin or the like as a technique for completely sealing the steel surface without forming the intermetallic compound. ing. However, since the titanium surface is completely covered with a very inert passive film mainly composed of titanium oxide, the adhesion of the resin is extremely poor, and the titanium lined material can be used for a long time in a high-humidity marine environment. It cannot be expected to completely seal the gaps in the steel structure. In addition, since epoxy resin does not have sufficient impact resistance compared to metal, when a drifting object collides with this seal portion due to a typhoon or the like, the seal may be broken by cracking or peeling off of the epoxy resin.

さらに、特許文献３所載の技術では、海中部のチタンライニング材と鋼材が隣接する部位において、異種金属接触による鋼材の腐食が発生する可能性がある。異種金属接触腐食を抑制する手法として電気防食が考えられるが、鋼材が充分防食できるような電位までカソード分極した場合には、分極によって発生した水素をチタンが吸蔵し、チタン板の脆化や水素誘起割れが発生するため鋼構造物に長期の防食性を付与することが困難である。   Furthermore, in the technique described in Patent Document 3, there is a possibility that corrosion of the steel material due to contact with different metals may occur at a site where the titanium lining material and the steel material in the sea part are adjacent to each other. Although anti-corrosion can be considered as a technique to suppress the contact corrosion of different metals, when cathode polarization is carried out to such a potential that the steel can be sufficiently protected, the hydrogen generated by the polarization is absorbed by titanium, and the titanium plate becomes brittle or hydrogen. Since induced cracking occurs, it is difficult to impart long-term corrosion resistance to steel structures.

以上のように、チタンそのものは極めて優れた耐食性金属であるものの、溶接性および異種金属接触腐食の観点から長期の鋼材の防食付与に供するのは適切ではない。   As described above, although titanium itself is an extremely excellent corrosion-resistant metal, it is not appropriate to provide long-term corrosion protection for steel from the viewpoint of weldability and dissimilar metal contact corrosion.

このように、耐食金属板による鋼材被覆に係る従来の技術は、海洋・河川・湖沼・運河等の腐食環境の厳しい地域で使用される鋼構造物に長期にわたって十分な耐食性を付与しうるものとはいえないのが現状である。   As described above, the conventional technology related to the coating of steel with a corrosion-resistant metal plate can provide sufficient corrosion resistance over a long period of time to steel structures used in severe corrosive environments such as the ocean, rivers, lakes, and canals. The current situation is not to say.

かかる従来技術の現状に鑑み、本発明は、耐食金属板による鋼材被覆技術において、腐食環境の厳しい地域で使用される鋼構造物に長期にわたって十分な耐食性を付与しうる防食性に優れた構造物構築部材およびその製造方法を提供することを目的とする。   In view of the current state of the prior art, the present invention is a structure excellent in anticorrosion property that can provide sufficient corrosion resistance over a long period of time to a steel structure used in an area where the corrosive environment is severe in the steel material coating technology using a corrosion resistant metal plate. It aims at providing a construction member and a manufacturing method for the same.

前記目的を達成した本発明は、以下のとおりである。   The present invention that has achieved the above object is as follows.

（１） 鋼材の表面の少なくとも一部を一枚又は複数枚の覆装板で被覆してなる構造物構築部材であって、前記覆装板は下記のＰＲＥが43以上になる板厚0.2 〜5.0mm のオーステナイト系耐海水ステンレス鋼からなり、前記覆装板を前記鋼材表面に仮止めしてなる第１の溶接部と、前記覆装板の端部同士の重なり部の隙を下記のＰＲＥが50以上の溶接棒を用いたＴＩＧ溶接により密封してなる第２の溶接部と、前記覆装板の被覆境界部と前記鋼材表面との隙を下記のＰＲＥが50以上の溶接棒を用いたＴＩＧ溶接により密封してなる第３の溶接部とを有し、かつ前記第２および第３の溶接部が前記オーステナイト系耐海水ステンレス鋼と同等以上の耐食性を有することを特徴とする構造物構築部材。
記
ＰＲＥ＝Cr＋3.3 ×Mo＋20×Ｎ。ただしＷ含有の場合は、ＰＲＥ＝Cr＋3.3 ×（Mo＋0.5 ×Ｗ）＋20×Ｎとする。ここに右辺の元素記号はその元素の濃度（mass% ）を表す。 (1) A structural construction member obtained by covering at least a part of the surface of a steel material with one or a plurality of covering plates, and the covering plate has a plate thickness of 0.2 to 43 below PRE. It consists 5.0mm austenitic seawater stainless steel, a first weld the KutsugaeSoban formed by tacking on the steel material surface, below the gap of the overlapping portion of the ends of the KutsugaeSoban PRE A gap between the second welded portion sealed by TIG welding using a welding rod of 50 or more and the covering boundary portion of the covering plate and the surface of the steel material is used for a welding rod having the following PRE of 50 or more. And a third welded portion sealed by TIG welding , and the second and third welded portions have a corrosion resistance equal to or higher than that of the austenitic seawater-resistant stainless steel. Construction member.
Record
PRE = Cr + 3.3 × Mo + 20 × N. However, in the case of containing W, PRE = Cr + 3.3 × (Mo + 0.5 × W) + 20 × N. Here, the element symbol on the right side represents the concentration (mass%) of the element.

（２） 鋼材の表面の少なくとも一部を一枚又は複数枚の覆装板で被覆してなる構造物構築部材であって、前記覆装板は下記のＰＲＥが43以上になる板厚0.2 〜5.0mm のオーステナイト系耐海水ステンレス鋼からなり、前記覆装板を前記鋼材表面に仮止めしてなる第１の溶接部と、前記覆装板の端部同士の重なり部を固定してなる第４の溶接部と、前記覆装板の端部同士の重なり部の隙を下記のＰＲＥが50以上の溶接棒を用いたＴＩＧ溶接により密封してなる第２の溶接部と、前記覆装板の被覆境界部と前記鋼材表面との隙を下記のＰＲＥが50以上の溶接棒を用いたＴＩＧ溶接により密封してなる第３の溶接部とを有し、かつ前記第２、第３の溶接部が前記オーステナイト系耐海水ステンレス鋼と同等以上の耐食性を有することを特徴とする構造物構築部材。 (2) A structural construction member formed by covering at least a part of the surface of a steel material with one or a plurality of covering plates, and the covering plate has a plate thickness of 0.2 to 43 in which the following PRE is 43 or more. A first welded portion made of 5.0 mm austenitic seawater resistant stainless steel, wherein the covering plate is temporarily fixed to the surface of the steel material, and an overlapping portion between the end portions of the covering plate is fixed. 4, a second welded portion in which the gap between the end portions of the covering plate is sealed by TIG welding using a welding rod having a PRE of 50 or more, and the covering plate And a third welded portion in which the following PRE is sealed by TIG welding using a welding rod having a PRE of 50 or more , and the second and third welds. The structure has a corrosion resistance equal to or higher than that of the austenitic seawater resistant stainless steel. Built members.

記
ＰＲＥ＝Cr＋3.3 ×Mo＋20×Ｎ。ただしＷ含有の場合は、ＰＲＥ＝Cr＋3.3 ×（Mo＋0.5 ×Ｗ）＋20×Ｎとする。ここに右辺の元素記号はその元素の濃度（mass% ）を表す。 PRE = Cr + 3.3 × Mo + 20 × N. However, in the case of containing W, PRE = Cr + 3.3 × (Mo + 0.5 × W) + 20 × N. Here, the element symbol on the right side represents the concentration (mass%) of the element.

（３） 前記構造物構築部材に、重防食塗料が塗装され、および／または前記構造物構築部材の鋼材に、電気防食用電極が装着されていることを特徴とする（１）または（２）に記載の構造物構築部材。 ( 3 ) The structure construction member is coated with a heavy anticorrosion paint, and / or a steel material for the structure construction member is equipped with an electrode for electrocorrosion protection (1) or (2) The structure construction member according to 1.

（４） 鋼材の表面に、下記のＰＲＥが43以上になるオーステナイト系耐海水ステンレス鋼からなる板厚0.2 〜5.0mm の複数枚の覆装板をその隣り合う端部同士が重なるように配置し、前記覆装板を前記鋼材表面に抵抗溶接で仮止め後、前記覆装板の端部同士の重なり部の隙、および前記覆装板の被覆境界部と前記鋼材表面との隙を、溶接電流50Ａ以上160 Ａ未満、溶接速度80mm/min以上600mm/min 未満の条件下で下記のＰＲＥが50以上の溶接棒を使用するＴＩＧ溶接により、密封することを特徴とする構造物構築部材の製造方法。 ( 4 ) A plurality of covering plates with a thickness of 0.2 to 5.0 mm made of austenitic seawater-resistant stainless steel with the following PRE of 43 or more are arranged on the surface of the steel so that the adjacent ends overlap each other. Then, after temporarily fixing the covering plate to the steel surface by resistance welding, welding the gap between the end portions of the covering plate and the gap between the covering boundary portion of the covering plate and the steel surface Manufacture of a structural construction member characterized by sealing by TIG welding using a welding rod having a PRE of 50 or more under the conditions of an electric current of 50 A or more and less than 160 A and a welding speed of 80 mm / min or more and less than 600 mm / min. Method.

記
ＰＲＥ＝Cr＋3.3 ×Mo＋20×Ｎ。ただしＷ含有の場合は、ＰＲＥ＝Cr＋3.3 ×（Mo＋0.5 ×Ｗ）＋20×Ｎとする。ここに右辺の元素記号はその元素の濃度（mass% ）を表す。 PRE = Cr + 3.3 × Mo + 20 × N. However, in the case of containing W, PRE = Cr + 3.3 × (Mo + 0.5 × W) + 20 × N. Here, the element symbol on the right side represents the concentration (mass%) of the element.

（５） 鋼材の表面に、下記のＰＲＥが43以上になるオーステナイト系耐海水ステンレス鋼からなる板厚0.2 〜5.0mm の複数枚の覆装板をその隣り合う端部同士が重なるように配置し、前記覆装板を前記鋼材表面に抵抗溶接で仮止め後、前記覆装板の重なり部を抵抗スポット溶接で固定し、さらに前記覆装板の端部同士の重なり部の隙、および前記覆装板の被覆境界部と前記鋼材表面との隙を、溶接電流50Ａ以上160 Ａ未満、溶接速度80mm/min以上600mm/min 未満の条件下で下記のＰＲＥが50以上の溶接棒を使用するＴＩＧ溶接により、密封することを特徴とする構造物構築部材の製造方法。 ( 5 ) Arrange a plurality of covering plates with a thickness of 0.2-5.0mm made of austenitic seawater-resistant stainless steel with the following PRE of 43 or more on the surface of the steel material so that the adjacent ends overlap each other. The covering plate is temporarily fixed to the steel surface by resistance welding, and then the overlapping portion of the covering plate is fixed by resistance spot welding, and further, the gap between the overlapping portions of the covering plate, and the covering TIG that uses welding rods with the following PRE of 50 or more under the conditions of a welding current of 50 A or more and less than 160 A, a welding speed of 80 mm / min or more and less than 600 mm / min, with a gap between the covering boundary of the plate and the steel surface. A method for manufacturing a structure building member, wherein the structure building member is sealed by welding.

記
ＰＲＥ＝Cr＋3.3 ×Mo＋20×Ｎ。ただしＷ含有の場合は、ＰＲＥ＝Cr＋3.3 ×（Mo＋0.5 ×Ｗ）＋20×Ｎとする。ここに右辺の元素記号はその元素の濃度（mass% ）を表す。 PRE = Cr + 3.3 × Mo + 20 × N. However, in the case of containing W, PRE = Cr + 3.3 × (Mo + 0.5 × W) + 20 × N. Here, the element symbol on the right side represents the concentration (mass%) of the element.

（６） 前記ＴＩＧ溶接による隙の密封後、前記構造物構築部材に、重防食塗料を塗装し、および／または前記構造物構築部材の鋼材に、電気防食用電極を装着することを特徴とする（４）または（５）に記載の構造物構築部材の製造方法。 ( 6 ) After sealing the gap by the TIG welding, the structure construction member is coated with a heavy anticorrosion paint, and / or an electrode for an anticorrosion is attached to the steel material of the structure construction member. (4) The manufacturing method of the structure construction member as described in (5) .

本発明によれば、耐食金属板による鋼材の被覆を効果的に行うことが可能となる。特に、被覆領域内部空間を密閉できるとともに被覆領域境界の隙間腐食を確実に防止できるようになるので、腐食環境の厳しい地域で使用される鋼構造物に長期にわたって十分な耐食性を付与することができるようになるという優れた効果を奏する。   According to the present invention, it is possible to effectively cover a steel material with a corrosion-resistant metal plate. In particular, since the internal space of the coating area can be sealed and the crevice corrosion at the boundary of the coating area can be surely prevented, sufficient corrosion resistance can be imparted to a steel structure used in an area where the corrosive environment is severe over a long period of time. There is an excellent effect of becoming.

本発明において、オーステナイト系耐海水ステンレス鋼とは、オーステナイト系ステンレス鋼のうち、JIS G 0578「ステンレス鋼の塩化第二鉄腐食試験方法」で測定された孔食発生臨界温度（：ＣＰＴ）が40℃以上になる耐食性を有するものを指す。   In the present invention, the austenitic seawater resistant stainless steel is austenitic stainless steel having a pitting corrosion critical temperature (: CPT) measured by JIS G 0578 “Method of ferric chloride corrosion test of stainless steel” of 40 It refers to those that have corrosion resistance that exceeds ℃.

図１は、本発明に係る構造物構築部材の１例を示す模式図である。例えば鋼管、鋼管杭等の鋼材１の表面の少なくとも一部が一枚又は複数枚の覆装板２で被覆されている。覆装板２は板厚が0.2 〜5.0mm のオーステナイト系耐海水ステンレス鋼板である。覆装板２は第１の溶接部３で鋼材１表面に仮止めされ、覆装板２、２の端部同士の重なり部２ａの隙が第２の溶接部４で密封され、覆装板２の被覆境界部と鋼材１表面との隙が第３の溶接部５で密封されている。   FIG. 1 is a schematic diagram showing an example of a structure building member according to the present invention. For example, at least a part of the surface of the steel material 1 such as a steel pipe or a steel pipe pile is covered with one or a plurality of covering plates 2. The covering plate 2 is an austenitic seawater resistant stainless steel plate having a thickness of 0.2 to 5.0 mm. The covering plate 2 is temporarily fixed to the surface of the steel material 1 by the first welding portion 3, and the gap of the overlapping portion 2 a between the end portions of the covering plates 2 and 2 is sealed by the second welding portion 4. The gap between the covering boundary portion 2 and the surface of the steel material 1 is sealed by the third welded portion 5.

図２は、本発明に係る構造物構築部材の１例を示す模式図である。図１と同じ符号で示すものは同一であることを意味する。覆装板２は第１の溶接部３および抵抗スポット溶接による第１の溶接部６で鋼板表面に仮止めされ、覆装板２，２の端部同士の重なり部２ａの隙が第２の溶接部４で密封され、覆装板２の被覆境界部と鋼材１表面との隙が第３の溶接部５で密封されている。   FIG. 2 is a schematic diagram showing an example of a structure building member according to the present invention. The same reference numerals as those in FIG. 1 mean the same thing. The covering plate 2 is temporarily fixed to the surface of the steel plate by the first welded portion 3 and the first welded portion 6 by resistance spot welding, and the gap of the overlapping portion 2a between the end portions of the covering plates 2 and 2 is the second. Sealed by the welded portion 4, and the gap between the covering boundary portion of the covering plate 2 and the surface of the steel material 1 is sealed by the third welded portion 5.

図３は、本発明に係る構造物構築部材の１例を示す模式図である。図１と同じ符号で示すものは同一であることを意味する。覆装板２は第１の溶接部３および抵抗シーム溶接による第１の溶接部８で鋼板表面に仮止めされ、覆装板２，２の端部同士の重なり部２ａの隙が第２の溶接部４で密封され、覆装板２の被覆境界部と鋼材１表面との隙が第３の溶接部５で密封されている。   FIG. 3 is a schematic view showing an example of a structure building member according to the present invention. The same reference numerals as those in FIG. 1 mean the same thing. The covering plate 2 is temporarily fixed to the surface of the steel plate by the first welded portion 3 and the first welded portion 8 by resistance seam welding, and the gap of the overlapping portion 2a between the end portions of the covering plates 2 and 2 is the second. Sealed by the welded portion 4, and the gap between the covering boundary portion of the covering plate 2 and the surface of the steel material 1 is sealed by the third welded portion 5.

図４は、本発明に係る構造物構築部材の１例を示す模式図である。図１と同じ符号で示すものは同一であることを意味する。覆装板２は第１の溶接部３および抵抗シーム溶接による第１の溶接部８および抵抗スポット溶接による第１の溶接部６で鋼板表面に仮止めされ、覆装板２，２の端部同士の重なり部２ａの隙が第２の溶接部４で密封され、覆装板２の被覆境界部と鋼材１表面との隙が第３の溶接部５で密封されている。   FIG. 4 is a schematic view showing an example of a structure building member according to the present invention. The same reference numerals as those in FIG. 1 mean the same thing. The covering plate 2 is temporarily fixed to the surface of the steel plate by the first welded portion 3, the first welded portion 8 by resistance seam welding, and the first welded portion 6 by resistance spot welding, and ends of the covering plates 2 and 2 The gap between the overlapping portions 2 a is sealed by the second welded portion 4, and the gap between the covering boundary portion of the covering plate 2 and the surface of the steel material 1 is sealed by the third welded portion 5.

図５は、本発明に係る構造物構築部材の１例を示す模式図である。図１と同じ符号で示すものは同一であることを意味する。覆装板２は第１の溶接部３で鋼板表面に仮止めされ、さらに覆装板２，２の端部同士の重なり部２ａが抵抗スポット溶接により第４の溶接部７で固定され、覆装板２，２の端部同士の重なり部２ａの隙が第２の溶接部４で密封され、覆装板２の被覆境界部と鋼材１表面との隙が第３の溶接部５で密封されている。   FIG. 5 is a schematic view showing an example of a structure building member according to the present invention. The same reference numerals as those in FIG. 1 mean the same thing. The covering plate 2 is temporarily fixed to the surface of the steel plate by the first welded portion 3, and the overlapping portion 2a between the end portions of the covering plates 2 and 2 is fixed by the fourth welded portion 7 by resistance spot welding. The gap of the overlapping portion 2 a between the end portions of the covering plates 2 and 2 is sealed by the second welded portion 4, and the gap between the covering boundary portion of the covering plate 2 and the surface of the steel material 1 is sealed by the third welded portion 5. Has been.

図６は、本発明に係る構造物構築部材の１例を示す模式図である。図１と同じ符号で示すものは同一であることを意味する。覆装板２は第１の溶接部３および抵抗スポット溶接による第１の溶接部６で鋼板表面に仮止めされ、さらに覆装板２，２の端部同士の重なり部２ａが抵抗スポット溶接により第４の溶接部７で固定され、覆装板２，２の端部同士の重なり部２ａの隙が第２の溶接部４で密封され、覆装板２の被覆境界部と鋼材１表面との隙が第３の溶接部５で密封されている。   FIG. 6 is a schematic view showing an example of a structure building member according to the present invention. The same reference numerals as those in FIG. 1 mean the same thing. The covering plate 2 is temporarily fixed to the surface of the steel plate by the first welding portion 3 and the first welding portion 6 by resistance spot welding, and the overlapping portion 2a between the end portions of the covering plates 2 and 2 is formed by resistance spot welding. Fixed by the fourth weld 7, the gap of the overlapping portion 2 a between the end portions of the covering plates 2, 2 is sealed by the second welding portion 4, and the covering boundary portion of the covering plate 2 and the surface of the steel 1 The gap is sealed by the third weld 5.

図７は、本発明に係る構造物構築部材の１例を示す模式図である。図１と同じ符号で示すものは同一であることを意味する。覆装板２は第１の溶接部３および抵抗シーム溶接による第１の溶接部８で鋼板表面に仮止めされ、さらに覆装板２，２の端部同士の重なり部２ａが抵抗スポット溶接により第４の溶接部７で固定され、覆装板２，２の端部同士の重なり部２ａの隙が第２の溶接部４で密封され、覆装板２の被覆境界部と鋼材１表面との隙が第３の溶接部５で密封されている。   FIG. 7 is a schematic view showing an example of a structure building member according to the present invention. The same reference numerals as those in FIG. 1 mean the same thing. The covering plate 2 is temporarily fixed to the surface of the steel plate by the first welding portion 3 and the first welding portion 8 by resistance seam welding, and the overlapping portion 2a between the end portions of the covering plates 2 and 2 is formed by resistance spot welding. Fixed by the fourth weld 7, the gap of the overlapping portion 2 a between the end portions of the covering plates 2, 2 is sealed by the second welding portion 4, and the covering boundary portion of the covering plate 2 and the surface of the steel 1 The gap is sealed by the third weld 5.

図８は、本発明に係る構造物構築部材の１例を示す模式図である。図１と同じ符号で示すものは同一であることを意味する。覆装板２は第１の溶接部３、抵抗シーム溶接による第１の溶接部８および抵抗スポット溶接による第１の溶接部６で鋼板表面に仮止めされ、さらに覆装板２，２の端部同士の重なり部２ａが抵抗スポット溶接により第４の溶接部７で固定され、覆装板２，２の端部同士の重なり部２ａの隙が第２の溶接部４で密封され、覆装板２の被覆境界部と鋼材１表面との隙が第３の溶接部５で密封されている。   FIG. 8 is a schematic view showing an example of a structure building member according to the present invention. The same reference numerals as those in FIG. 1 mean the same thing. The covering plate 2 is temporarily fixed to the surface of the steel plate by the first welded portion 3, the first welded portion 8 by resistance seam welding, and the first welded portion 6 by resistance spot welding. The overlapping part 2a between the parts is fixed by the fourth welding part 7 by resistance spot welding, and the gap of the overlapping part 2a between the end parts of the covering plates 2 and 2 is sealed by the second welding part 4, A gap between the covering boundary portion of the plate 2 and the surface of the steel material 1 is sealed by the third welded portion 5.

さらに、本発明では前述した第２の溶接部４および第３の溶接部５におけるＣＰＴが40℃以上である。   Furthermore, in this invention, CPT in the 2nd weld part 4 and the 3rd weld part 5 which were mentioned above is 40 degreeC or more.

また、本発明では、溶接性と耐食性の観点から、鋼材に被覆する覆装板としては、オーステナイト系耐海水ステンレス鋼板を用いる。オーステナイト系以外のステンレス鋼板では、炭素鋼との溶接性が悪く、炭素鋼からなる鋼材にライニングすることが困難である。また、オーステナイト系ステンレス鋼板であってもＣＰＴが40℃未満のものは耐海水性に乏しく、海洋地域での長期使用に耐えない。   In the present invention, from the viewpoint of weldability and corrosion resistance, an austenitic seawater-resistant stainless steel plate is used as the covering plate that covers the steel material. Stainless steel plates other than austenitic steel have poor weldability with carbon steel, and it is difficult to line the steel material made of carbon steel. Even austenitic stainless steel sheets having a CPT of less than 40 ° C. have poor seawater resistance and cannot withstand long-term use in marine areas.

なお、さらに良好な溶接性と耐食性を確保する観点から、前記オーステナイト系耐海水ステンレス鋼は、前記ＰＲＥの値が43以上になる組成のものが好ましい。かかるオーステナイト系耐海水ステンレス鋼の適合例（S1、S2）と不適合例（S3）を表１に示す。   From the viewpoint of ensuring better weldability and corrosion resistance, the austenitic seawater resistant stainless steel preferably has a composition with a PRE value of 43 or more. Examples of conformity (S1, S2) and non-conformity (S3) of such austenitic seawater resistant stainless steel are shown in Table 1.

Figure 0004262018
Figure 0004262018

前記覆装板の板厚は、耐衝撃性と施工性の観点から0.2 〜5.0mm とする。覆装板の板厚が0.2mm よりも薄いと、鋼材との溶接が困難となり、施工性が低下するばかりか、設置後の構造物構築部材の被覆部に流木や船舶が当った際に、その衝撃により覆装板が破損して防食性が失われる可能性が高い。一方、覆装板の板厚が5.0mm よりも厚いと、コストが急激に増大するだけでなく、重量が過大でハンドリングが困難となり鋼材被覆作業効率が著しく低下する。   The thickness of the covering plate is 0.2 to 5.0 mm from the viewpoint of impact resistance and workability. If the thickness of the cover plate is less than 0.2mm, welding with the steel material becomes difficult, and not only the workability deteriorates, but also when the driftwood or ship hits the cover of the structure construction member after installation, There is a high possibility that the covering plate is damaged by the impact and the corrosion resistance is lost. On the other hand, if the thickness of the covering plate is thicker than 5.0 mm, not only will the cost increase rapidly, but the weight will be excessive and difficult to handle, and the steel covering efficiency will be significantly reduced.

第１の溶接部３、６、８は、被覆板を鋼材表面の所定の位置に仮止めし、第２、第３、第４の溶接部４、５、７を形成する溶接施工時の位置ずれを防いでいる。   The 1st welding parts 3, 6, and 8 are the positions at the time of welding construction which temporarily fix | stop a covering plate in the predetermined position of the steel material surface, and form the 2nd, 3rd, 4th welding parts 4, 5, and 7 Prevents slippage.

第２の溶接部４は、覆装板２、２の端部同士の重なり部２ａに形成される上板の端面と下板の板面との隙を密封している（図１〜図８；（ｂ））。また、第３の溶接部５は、覆装板２の被覆境界部と鋼材１表面との隙を密封している（図１〜図８；（ｃ））。これにより、覆装板２で覆われた鋼材表面部分は外部から遮断され、厳しい腐食環境から保護される。第４の溶接部７は、覆装板２、２の端部同士の重なり部２ａを固定し、第２、第３の溶接部４、５を形成する溶接施工時の位置ずれを効果的に防止することができる。   The second welded portion 4 seals the gap between the end surface of the upper plate and the plate surface of the lower plate formed in the overlapping portion 2a between the end portions of the covering plates 2 and 2 (FIGS. 1 to 8). (B)). Moreover, the 3rd welding part 5 has sealed the clearance gap between the coating | coated boundary part of the covering board 2, and the steel material 1 surface (FIGS. 1-8; (c)). Thereby, the steel material surface part covered with the covering board 2 is interrupted | blocked from the outside, and is protected from a severe corrosive environment. The 4th welding part 7 fixes the overlap part 2a of the edge parts of the covering plates 2 and 2, and the position shift at the time of the welding construction which forms the 2nd and 3rd welding parts 4 and 5 is effective. Can be prevented.

なお、第２の溶接部４は、その範囲が鋼材１までは達していないものとすることが好ましい。第２の溶接部４の範囲が鋼材１にまで及んだものは、オーステナイト系耐海水ステンレス鋼板への溶接入熱量が過大であって、その熱影響部ではクロムカーバイドの析出により粒界にクロム欠乏層が形成され、耐食性が低下するおそれがあるからである。   In addition, it is preferable that the range of the second welded portion 4 does not reach the steel material 1. In the case where the range of the second welded part 4 extends to the steel material 1, the amount of heat input to the austenitic seawater-resistant stainless steel plate is excessive, and in the heat-affected zone, chromium is precipitated at the grain boundaries due to the precipitation of chromium carbide. This is because a deficient layer is formed and the corrosion resistance may be lowered.

また、第２、第３の溶接部は、覆装板であるオーステナイト系耐海水ステンレス鋼板と同等以上の耐食性をもたせたもの、すなわち前記ＣＰＴが40℃以上の性能を有するものとする。第２、第３の溶接部のＣＰＴが40℃未満では、この部位で孔食及び隙間腐食が進行し、長期の耐食性は望めない。   In addition, the second and third welds have corrosion resistance equivalent to or higher than that of the austenitic seawater-resistant stainless steel plate as the covering plate, that is, the CPT has a performance of 40 ° C. or higher. When the CPT of the second and third welds is less than 40 ° C., pitting corrosion and crevice corrosion proceed at this portion, and long-term corrosion resistance cannot be expected.

また、本発明の構造物構築部材では、海中部に配設される部分の海水中における異種金属接触腐食とステンレス鋼の隙間腐食の抑制を目的として、構造物構築部材の鋼材に電気防食用電極を装着し、電気防食を併用することが好ましい。電気防食の方法は特に限定しないが、外部電源方式や犠牲陽極方式が挙げられ、防食電位としては-770〜-1000mV vs.SCEが好ましい。一方、海上部に配設される部分については、台風時などにおける漂流物等の衝突が起こらず樹脂被覆層の割れや剥落が発生しないので、構造物構築部材の表面に重防食塗料を塗装したものとするのが好ましい。これによりさらに長期の耐食性を確保することが可能となる。重防食塗料の塗装は少なくとも非ライニング部に施せばよいが、ステンレス被覆部表面にも被覆境界部から50mm以上施されることが好ましい。重防食塗料の具体例としては、重防食ウレタン塗料、超厚膜型エポキシ塗料や水中硬化型エポキシ塗料等が挙げられるが、本発明では特にこれらに限定するものではない。   In addition, in the structure building member of the present invention, the electrode for cathodic protection is applied to the steel of the structure building member for the purpose of suppressing contact corrosion of dissimilar metals and crevice corrosion of stainless steel in seawater at a portion disposed in the sea. It is preferable to use a combination of anticorrosion. There are no particular restrictions on the method of cathodic protection, but examples include an external power supply method and a sacrificial anode method, and the anticorrosion potential is preferably -770 to -1000 mV vs. SCE. On the other hand, the parts placed on the sea are coated with heavy anti-corrosion paint on the surface of the structure construction member because there is no collision with drifting objects during typhoons and the resin coating layer does not crack or peel off. Preferably. Thereby, it becomes possible to ensure further long-term corrosion resistance. The heavy anticorrosion paint may be applied to at least the non-lining portion, but it is preferably applied to the surface of the stainless steel coating portion by 50 mm or more from the coating boundary portion. Specific examples of heavy anticorrosion paints include heavy anticorrosion urethane paints, ultra-thick film type epoxy paints, underwater curing type epoxy paints, and the like, but the present invention is not particularly limited thereto.

本発明では、コイルから切出したオーステナイト系耐海水ステンレス鋼板（以下、単にステンレス鋼板ともいう。）を鋼材表面に被覆する際に、鋼構造物の形状とステンレス鋼板の板厚に応じて事前にステンレス鋼板に曲げ加工を施してもよい。例えば、板厚0.4mm のステンレス鋼板を径の大きい鋼管に巻き付ける場合には、コイルからステンレス鋼板を所定の寸法で切出した後、特段の加工を施すことなく鋼管の表面に這わせ、固定することにより容易かつ安価に被覆できる。一方、板厚2.0mm のステンレス鋼板を鋼管の表面に被覆する場合には、コイルまたは切板から所定の寸法のステンレス鋼板を切出し、プレス加工や曲げ加工等によってステンレス鋼板を所定の形状に成形した後に鋼管に取付けることにより、寸法精度よく被覆できるようになる。   In the present invention, when an austenitic seawater-resistant stainless steel plate (hereinafter also simply referred to as a stainless steel plate) cut out from a coil is coated on the surface of the steel material, the stainless steel is preliminarily formed according to the shape of the steel structure and the thickness of the stainless steel plate. The steel sheet may be bent. For example, when a stainless steel plate with a thickness of 0.4 mm is wound around a steel pipe with a large diameter, the stainless steel plate is cut out from the coil to a predetermined size and then placed on the surface of the steel pipe without special processing. Can be easily and inexpensively coated. On the other hand, when a steel plate with a thickness of 2.0 mm is coated on the surface of a steel pipe, a stainless steel plate of a predetermined size is cut out from a coil or a cut plate, and the stainless steel plate is formed into a predetermined shape by pressing or bending. By attaching to the steel pipe later, it becomes possible to cover with dimensional accuracy.

本発明では、鋼材表面被覆用に切出したステンレス鋼板（前記覆装板に相当）を鋼材表面に被覆する際には、まず１番目に用いる覆装板を鋼材表面に抵抗溶接で仮止めする。次に２番目に用いる覆装板を、１番目のものと端部同士が所定の重なり幅で重なり合うように鋼材表面に被覆（：所謂重ね継ぎ被覆）し、鋼材表面に抵抗溶接で仮止めする。同様に、所定の枚数の覆装板を順次抵抗溶接で仮止めして鋼材表面全周をステンレス鋼板で重ね継ぎ被覆する。また、鋼材に覆装板を重ね継ぎ被覆する方向は特に限定しない。例えば鋼管に覆装板を重ね継ぎ被覆する場合には、鋼管の円周方向にわたって複数枚の覆装板を重ね継ぎ被覆する方法、あるいは鋼管の管長方向にわたって複数枚の覆装板を重ね継ぎ被覆する方法、いずれでもかまわない。仮止めには利便性の面から抵抗溶接を用いる。この仮止め部が前記第１の溶接部に相当する。   In the present invention, when a stainless steel plate (corresponding to the covering plate) cut out for covering the steel surface is coated on the surface of the steel material, the covering plate used first is temporarily fixed to the steel surface by resistance welding. Next, a second covering plate is coated on the surface of the steel material so that the first and the end portions overlap with each other with a predetermined overlap width (so-called lap joint coating), and temporarily fixed to the steel surface by resistance welding. . Similarly, a predetermined number of covering plates are sequentially temporarily fixed by resistance welding, and the entire circumference of the steel material is overlap-coated with a stainless steel plate. Further, the direction in which the covering plate is overlapped and coated on the steel material is not particularly limited. For example, when covering a steel pipe with a cover plate, the method of covering a plurality of cover plates over the circumferential direction of the steel pipe, or a method of covering a plurality of cover plates over the pipe length of the steel pipe You can use either method. Resistance welding is used for temporary fixing for convenience. This temporary fixing portion corresponds to the first welded portion.

第１の溶接部を形成する抵抗溶接としては、抵抗スポット溶接、インダイレクト抵抗スポット溶接、抵抗シーム溶接、インダイレクト抵抗シーム溶接が挙げられる。溶接部が外界と接する場合には、溶接部の耐食性を低下させないために、抵抗スポット溶接により第１の溶接部6、8を形成することが好ましい。   Examples of resistance welding that forms the first weld include resistance spot welding, indirect resistance spot welding, resistance seam welding, and indirect resistance seam welding. When the welded portion is in contact with the outside world, the first welded portions 6 and 8 are preferably formed by resistance spot welding in order not to reduce the corrosion resistance of the welded portion.

また、第２の溶接部を形成するＴＩＧ溶接を施工する際の覆装板の位置ずれを防止するために、第１の溶接部として、図１〜図８に示す第１の溶接部３に加え、さらに、抵抗スポット溶接および／または抵抗シーム溶接により第１の溶接部６、８を形成し仮止めすることが好ましい。   Moreover, in order to prevent the position shift of the covering board at the time of constructing TIG welding which forms a 2nd weld part, as the 1st weld part, in 1st weld part 3 shown in FIGS. In addition, the first welds 6 and 8 are preferably formed and temporarily fixed by resistance spot welding and / or resistance seam welding.

図２、４、６、８には抵抗スポット溶接による第１の溶接部６を示す。この抵抗スポット溶接による第１の溶接部６は、その中心が覆装板の上板の端部が位置する鋼材１表面の位置Ｃから３〜50mmに位置し、また抵抗スポット溶接の中心同士の間隔が５〜50mmであることが好ましい。抵抗スポット溶接の中心位置が50mm超の場合、または溶接間隔が50mm超の場合は、覆装板の仮止めの効果が充分でなく、一方、抵抗スポット溶接の中心位置が３mm未満の場合、または溶接間隔が５mm未満の場合は、溶接施工における作業性が劣るおそれがあるからである。   2, 4, 6, and 8 show the first weld 6 by resistance spot welding. The center of the first welded portion 6 by this resistance spot welding is 3 to 50 mm from the position C on the surface of the steel material 1 where the end of the upper plate of the covering plate is located. The interval is preferably 5 to 50 mm. If the center position of resistance spot welding is more than 50 mm, or if the welding interval is more than 50 mm, the temporary fixing of the covering plate is not sufficient, while the center position of resistance spot welding is less than 3 mm, or This is because, when the welding interval is less than 5 mm, workability in welding construction may be deteriorated.

図３、４、７、８には抵抗シーム溶接による第１の溶接部８を示す。この抵抗シーム溶接による第１の溶接部８は覆装板の下板またはその端部を鋼材表面に仮止めするものとすることが好ましい。図３、４、７、８に示す様に下板の端部を第１の溶接部８により仮止めする場合がさらに好ましい。また、この第１の溶接部８は第２の溶接部４により外界から隔離されることになるので高度の防食性は要求されないことから、拘束力の強い抵抗シーム溶接により形成することが好ましい。   3, 4, 7, and 8 show the first weld 8 by resistance seam welding. It is preferable that the first welded portion 8 by resistance seam welding temporarily fixes the lower plate of the covering plate or its end to the steel surface. As shown in FIGS. 3, 4, 7, and 8, it is more preferable that the end portion of the lower plate is temporarily fixed by the first welded portion 8. Moreover, since this 1st welding part 8 is isolated from the external field by the 2nd welding part 4, since high corrosion resistance is not requested | required, it is preferable to form by resistance seam welding with a strong restraint force.

覆装板端部同士の重なり幅は10mm以上とするのが好ましい。この重なり幅が10mm未満の場合、抵抗溶接部と後述するＴＩＧ溶接部とが重なる場合が生じ、その場合、重なる部分が２回加熱されることとなり、溶接熱影響部の表面に酸化スケールが成長して耐食性を劣化させるおそれがあるからである。また、この重なり幅は500mm 以下とすることが好ましい。500mm 超では覆装板の使用量の増大によりコストが増加するのみならず、下板を鋼材に固定した溶接部と覆装板同士の重なり部を密封するＴＩＧ溶接部との距離が増加するため、仮止め溶接による固定の効果が減じるおそれがあるからである。   The overlapping width between the end portions of the covering plate is preferably 10 mm or more. If this overlap width is less than 10 mm, the resistance weld and the TIG weld described later may overlap. In this case, the overlap will be heated twice, and an oxide scale will grow on the surface of the weld heat affected zone. This is because the corrosion resistance may be deteriorated. The overlapping width is preferably 500 mm or less. Above 500mm, not only will the cost increase due to the increase in the amount of covering plate used, but also the distance between the welded portion where the lower plate is fixed to the steel and the TIG welded portion that seals the overlap between the covering plates will increase. This is because the fixing effect by temporary fixing welding may be reduced.

なお、仮止めに先立って覆装板の位置を仮決めするためにプラスチック製バンド等の補助具を用いてもかまわない。   An auxiliary tool such as a plastic band may be used to temporarily determine the position of the covering plate prior to temporary fixing.

さらにまた、第２の溶接部を形成するＴＩＧ溶接を施工する際の覆装板の位置ずれを防止するために、第１の溶接部３、６、８に加え、さらに、抵抗スポット溶接により覆装板の端部同士の重なり部に第４の溶接部７を形成し固定することが好ましい。   Furthermore, in order to prevent displacement of the covering plate when performing TIG welding for forming the second welded portion, in addition to the first welded portions 3, 6 and 8, it is further covered by resistance spot welding. It is preferable to form and fix the fourth welded portion 7 at the overlapping portion between the end portions of the mounting plate.

図５、６、７、８には抵抗スポット溶接による第４の溶接部７を示す。この抵抗スポット溶接による第４の溶接部７はその中心が覆装板上板の端部が位置する覆装板下板表面の位置Ｄから３〜50mmに位置し、また抵抗スポット溶接の中心同士の間隔が５〜50mmであることが好ましい。抵抗スポット溶接の中心位置が50mm超の場合、または溶接間隔が50mm超の場合は、覆装板の仮止めの効果が充分でなく、一方、抵抗スポット溶接の中心位置が３mm未満の場合、または溶接間隔が５mm未満の場合は、溶接施工における作業性が劣るおそれがあるからである。   5, 6, 7 and 8 show a fourth weld 7 by resistance spot welding. The center of the fourth welded portion 7 by resistance spot welding is located 3 to 50 mm from the position D of the lower surface of the covering plate where the end of the upper plate of the covering plate is located. Is preferably 5 to 50 mm. If the center position of resistance spot welding is more than 50 mm, or if the welding interval is more than 50 mm, the temporary fixing of the covering plate is not sufficient, while the center position of resistance spot welding is less than 3 mm, or This is because, when the welding interval is less than 5 mm, workability in welding construction may be deteriorated.

第１の溶接部による仮止め、またはさらに第４の溶接部による固定が完了すると、鋼材長手方向の所定部分の表面の全周がステンレス鋼板で重ね継ぎ被覆された状態となっているが、その被覆領域内の鋼材表面はまだ外界に開放されている。そこで次にこの被覆領域の境界部の隙、すなわちステンレス鋼板端面と鋼材表面間の隙（１次隙）、およびステンレス鋼板端部同士の重なり部の上板端面と下板表面間の隙（２次隙）を密封する。   When temporary fixing by the first welded portion, or further fixing by the fourth welded portion is completed, the entire circumference of the surface of the predetermined portion in the longitudinal direction of the steel material is in a state of being lap-coated with a stainless steel plate, The steel surface in the coating area is still open to the outside world. Then, next, the gap at the boundary of this covering region, that is, the gap between the stainless steel plate end surface and the steel surface (primary gap), and the gap between the upper plate end surface and the lower plate surface of the overlapping portion of the stainless steel plate ends (2 Next gap) is sealed.

この密封は、これら隙をなす部材を重ね隅肉溶接することにより行なう。１次隙の密封溶接部が前記第３の溶接部、２次隙の密封溶接部が前記第２の溶接部に対応する。   This sealing is performed by laminating fillet welds of these gap members. The primary gap sealed weld corresponds to the third weld and the secondary gap sealed weld corresponds to the second weld.

この重ね隅肉溶接は、被覆された鋼材表面を腐食環境から完全に遮断して長期の耐食性を付与し、被覆したステンレス鋼板を鋼材表面に力学的に固定し、さらにステンレス鋼板端面における隙間腐食を完全に防止する。このために、溶接電流50Ａ以上160 Ａ未満、溶接速度80mm/min以上600mm/min 未満の条件で前記ＰＲＥが50以上になる溶接棒（溶加材またはフィラーともいう。）を用いるＴＩＧ溶接により行なう必要がある。ＴＩＧ溶接電流が50Ａ未満あるいはＴＩＧ溶接速度が600mm/min 以上の場合、入熱量の低下により十分なビードが形成されず溶接部の強度が著しく低下する。一方、ＴＩＧ溶接電流が160 Ａ以上あるいはＴＩＧ溶接速度が80mm/min未満の場合、覆装板同士の重ね隅肉溶接において溶接部が下板の板厚を貫通するだけではなく、覆装板と鋼材との重ね隅肉溶接部においても、クロムカーバイドの析出により粒界にクロム欠乏層が形成されるだけでなく、ビード近傍のステンレス表面に酸化スケールが形成されるため、溶接ビード部周囲の熱影響部の防食性が著しく低下する。   This lap fillet welding provides long-term corrosion resistance by completely shielding the coated steel surface from the corrosive environment, mechanically fixing the coated stainless steel plate to the steel surface, and further crevice corrosion at the end surface of the stainless steel plate. Prevent completely. For this purpose, TIG welding is performed by using a welding rod (also referred to as filler material or filler) having a PRE of 50 or more under the conditions of a welding current of 50 A or more and less than 160 A and a welding speed of 80 mm / min or more and less than 600 mm / min. There is a need. When the TIG welding current is less than 50 A or the TIG welding speed is 600 mm / min or more, a sufficient bead is not formed due to a decrease in heat input, and the strength of the welded portion is significantly reduced. On the other hand, when the TIG welding current is 160 A or more or the TIG welding speed is less than 80 mm / min, the welded portion not only penetrates the thickness of the lower plate in the overlap fillet welding of the covering plates, Even in a lap fillet weld with steel, not only a chromium-depleted layer is formed at the grain boundary due to the precipitation of chromium carbide, but also an oxide scale is formed on the stainless steel surface near the bead. The corrosion resistance of the affected area is significantly reduced.

なお、ＴＩＧ溶接を施す場合には、溶接する部分の隙間が0.1mm 未満になるよう押さえロールで制御することが好ましい。特に溶接する覆装板の板厚が0.8mm 以下の場合には、溶接時に0.1mm 以上の隙間が存在すると覆装板からの抜熱が阻害され、溶接欠陥が生じるおそれがあるからである。本発明では、押さえロールが溶接トーチの前方に位置すればトーチからの距離やその大きさを限定しないが、一例として、押さえロールの中心とトーチの距離が５〜50mm、押さえロールの直径10〜50mm等が挙げられる。   In addition, when performing TIG welding, it is preferable to control with a press roll so that the clearance of the part to weld may be less than 0.1 mm. In particular, when the thickness of the covering plate to be welded is 0.8 mm or less, if there is a gap of 0.1 mm or more during welding, heat removal from the covering plate may be hindered and a welding defect may occur. In the present invention, if the pressing roll is positioned in front of the welding torch, the distance from the torch and the size thereof are not limited, but as an example, the distance between the center of the pressing roll and the torch is 5 to 50 mm, and the diameter of the pressing roll is 10 to 50mm etc. are mentioned.

また、イナートガス例えばArガスの流量は５〜15l/minが好ましい。Arガス流量が５l/min 未満の場合には、溶接時のアークが不安定となり溶接ビード部の酸化を十分に抑制し難く、一方、Arガス流量が15l/min 超の場合には、溶接部の冷却速度が過大となり良好な溶接ビードを得難い。   The flow rate of the inert gas such as Ar gas is preferably 5 to 15 l / min. When the Ar gas flow rate is less than 5 l / min, the arc during welding becomes unstable and it is difficult to sufficiently suppress oxidation of the weld bead. On the other hand, when the Ar gas flow rate exceeds 15 l / min, the weld zone It is difficult to obtain a good weld bead due to excessive cooling rate.

さらに、溶接ビードの耐食性を長期間維持するために、溶接ビード部の耐食性金属の希釈を抑制しなければならず、そのため本発明のＴＩＧ溶接では、前記ＰＲＥが50以上になる化学組成のフィラーを用いなければならない。かかるフィラーの具体例を表２に示す。   Furthermore, in order to maintain the corrosion resistance of the weld bead for a long period of time, dilution of the corrosion resistant metal in the weld bead portion must be suppressed. Therefore, in the TIG welding of the present invention, a filler having a chemical composition that makes the PRE 50 or more is used. Must be used. Specific examples of such fillers are shown in Table 2.

Figure 0004262018
Figure 0004262018

このようなフィラーを用いて前記電流・速度条件でＴＩＧ溶接してなる第２、第３の溶接部は前記ＣＰＴが40℃以上の性能を有するものとなる。   The second and third welds formed by TIG welding under the current / speed conditions using such a filler have the CPT of 40 ° C. or higher.

なお、フィラーの好適な送り速度は溶接棒の径および覆装板の板厚によって異なるが、例えば、1.0mm φの溶接棒を使用する場合、板厚0.4mm の場合には80〜200mm/min 、板厚1.5mm の場合には300 〜500mm/min がそれぞれ好ましい。他の板厚の場合、これらから線型補間（内挿・外挿）した値が好ましい。フィラーの送り速度が上記好適範囲の下限を下回った場合には、ビード部が小さくなるばかりでなく耐食性金属成分の希釈が発生し耐食性が著しく低下する。一方、フィラーの送り速度が上記好適範囲の上限を超えた場合には、溶接部に投入した熱量の大部分がフィラーの溶融に消費されるため、溶接ビード部の溶け込み量が減少し溶接強度が低下するだけでなく、ビード形状の維持も困難になる。   The suitable feed rate of the filler varies depending on the diameter of the welding rod and the thickness of the covering plate.For example, when using a 1.0 mm φ welding rod, the plate thickness is 0.4 to 80 mm / min. When the plate thickness is 1.5 mm, 300 to 500 mm / min is preferable. In the case of other plate thicknesses, values obtained by linear interpolation (interpolation / extrapolation) from these are preferable. When the feed rate of the filler falls below the lower limit of the above preferred range, not only the bead portion becomes small, but also the corrosion-resistant metal component is diluted and the corrosion resistance is remarkably lowered. On the other hand, when the filler feed rate exceeds the upper limit of the above preferred range, most of the heat input to the welded portion is consumed for melting the filler, so the penetration amount of the weld bead portion is reduced and the welding strength is reduced. Not only does this decrease, it also becomes difficult to maintain the bead shape.

また、本発明では、前記ＴＩＧ溶接の完了後、必要に応じて前述した電気防食措置または重防食塗装を施すことが好ましい。電気防食措置は、本発明の構造物構築部材の鋼材に電気防食用電極をスポット溶接等で装着するものである。電気防食の方法は特に限定しないが、外部電源方式や犠牲陽極方式が挙げられ、防食電位としては-770〜-1000mV vs.SCEが好ましい。一方、重防食塗装は、少なくとも覆装板で被覆された以外の部分（非ライニング部という）に重防食塗料を塗装するものである。重防食塗料の具体例としては、重防食ウレタン塗料、超厚膜型エポキシ塗料や水中硬化型エポキシ塗料等が挙げられるが、本発明では特にこれらに限定するものではない。   In the present invention, it is preferable to apply the above-described cathodic protection or heavy anticorrosion coating as necessary after the completion of the TIG welding. In the anticorrosion measure, an electrode for anticorrosion is attached to the steel material of the structure building member of the present invention by spot welding or the like. There are no particular restrictions on the method of cathodic protection, but examples include an external power supply method and a sacrificial anode method, and the anticorrosion potential is preferably -770 to -1000 mV vs. SCE. On the other hand, heavy anti-corrosion coating is a method in which a heavy anti-corrosion paint is applied to at least a portion (referred to as a non-lining portion) other than that covered with a covering plate. Specific examples of the heavy anticorrosion paint include a heavy anticorrosion urethane paint, an ultra-thick film type epoxy paint, an underwater curing type epoxy paint, and the like, but the present invention is not particularly limited thereto.

（実施例１）
鋼材として炭素鋼からなる鋼管表面の黒皮をブラスト処理で取り除いてなる鋼管杭を用いた。覆装板として、板厚0.4mm のオーステナイト系耐海水ステンレス鋼（表１のS1）の帯板コイルから鋼管杭の寸法に合わせた所定長さだけ巻き戻して切断することにより複数枚切出したものを用いた。 (Example 1)
The steel pipe pile which removed the black skin of the steel pipe surface which consists of carbon steel by blasting as steel materials was used. A cover plate made of austenite seawater resistant stainless steel (S1 in Table 1) with a thickness of 0.4mm was cut out by unwinding and cutting a predetermined length according to the dimensions of the steel pipe pile. Was used.

複数の覆装板を順次インダイレクト抵抗スポット溶接により鋼管杭表面に仮止め溶接し（第１の溶接部３形成）、互いの端部を重ね合わせて鋼管杭表面の円周方向に這わせて一周させることにより、鋼管杭の両端部３ｍから内側の領域をステンレス鋼板による重ね継ぎ被覆部となした。前記インダイレクト抵抗スポット溶接は、ステンレス鋼板の端面から50mm以上内側で、かつ、後程行うＴＩＧ溶接の熱影響部と重ならない適宜の位置で行なった。ステンレス鋼板同士の重なり部の幅は30〜50mmとした。ここでのインダイレクト抵抗スポット溶接の施工条件を以下に示す。
・インダイレクト抵抗スポット溶接（施工条件INDSP-1 ）
溶接電流：6500Ａ
電極径：溶接側、非溶接側（アース側）とも16mmφ
加圧力：溶接側、非溶接側（アース側）とも2.0kN/mm2
電極間距離：200mm
スポット溶接間隔：150mm
次いで、前記ステンレス鋼板の重なり部の上板端面と下板表面とがなす段差部（鋼管杭長さ方向に延在）をその全長にわたりＴＩＧ溶接により重ね隅肉溶接し（第２の溶接部４形成）、該段差部の隅に存在していた隙を密封した。さらに、前記重ね継ぎ被覆部の境界においてステンレス鋼板端面と鋼管杭表面とがなす段差部（鋼管杭円周方向に延在）をその全長にわたりＴＩＧ溶接により重ね隅肉溶接し（第３の溶接部５形成）、該段差部の隅に存在していた隙を密封した。ここでのＴＩＧ溶接の施工条件を以下に示す。
・ＴＩＧ溶接（施工条件TIG-1 ）
溶接電流：80Ａ
溶接速度：140mm/min
Arガス流量：10l/min
フィラー：表２のF4
フィラー送り速度：140mm/min
なお、前記鋼材と同一組成・同一厚さの鋼材試片および前記被覆板と同一組成・同一厚さのステンレス鋼板試片とを用いて同様のＴＩＧ溶接により作製した鋼材試片とステンレス鋼板試片の重ね隅肉溶接継手試料、およびステンレス鋼板試片同士の重ね隅肉溶接継手試料の各溶接部について測定したＣＰＴ値はそれぞれ50℃、60℃であった。このようにして図１に示す構造物構築部材を製造した。 A plurality of covering plates are sequentially temporarily welded to the surface of the steel pipe pile by indirect resistance spot welding (formation of the first welded portion 3), and the end portions of the covering plates are overlapped in the circumferential direction of the steel pipe pile surface. By making one round, the inner region from both end portions 3m of the steel pipe pile became a lap joint covering portion made of a stainless steel plate. The indirect resistance spot welding was performed at an appropriate position not less than 50 mm inside from the end surface of the stainless steel plate and not overlapping with the heat affected zone of TIG welding performed later. The width of the overlapping part between the stainless steel plates was 30-50 mm. The construction conditions of indirect resistance spot welding here are shown below.
・ Indirect resistance spot welding (Construction conditions INDSP-1)
Welding current: 6500A
Electrode diameter: 16mmφ for both welded side and non-welded side (ground side)
Pressure: 2.0kN / mm 2 for both welded side and non-welded side (ground side)
Distance between electrodes: 200mm
Spot welding interval: 150mm
Next, a stepped portion (extending in the length direction of the steel pipe pile) formed by the upper plate end surface and the lower plate surface of the overlapping portion of the stainless steel plate is overlapped and welded by TIG welding over the entire length (second welded portion 4). Formation), the gap that existed in the corner of the step was sealed. Further, a step portion (extending in the circumferential direction of the steel pipe pile) formed by the end face of the stainless steel plate and the steel pipe pile surface at the boundary of the lap joint covering part is overlapped and welded by TIG welding over the entire length (third welded part). 5 formation), the gap existing in the corner of the stepped portion was sealed. The construction conditions of TIG welding here are shown below.
・ TIG welding (Construction conditions TIG-1)
Welding current: 80A
Welding speed: 140mm / min
Ar gas flow rate: 10l / min
Filler: F4 in Table 2
Filler feed rate: 140mm / min
A steel specimen and a stainless steel specimen prepared by the same TIG welding using a steel specimen having the same composition and thickness as the steel and a stainless steel specimen having the same composition and thickness as the covering plate. The CPT values measured for the welds of the lap fillet welded joint sample and the lap fillet welded joint sample of the stainless steel plate specimens were 50 ° C. and 60 ° C., respectively. Thus, the structure building member shown in FIG. 1 was manufactured.

前記ＴＩＧ溶接完了後、ステンレス鋼板に覆われていない鋼管杭の両端部３ｍの領域について、該両端部の一方に重防食塗装、他方に電気防食措置を施した。この重防食塗装では、前記重ね継ぎ被覆部の境界のＴＩＧ溶接部から該被覆部側に50mm入った部分のステンレス鋼板表面をサンドペーパで研削し、該研削部からこれに連なる露出した鋼管杭の端にかけての領域を、ポリウレタンプライマー（330 プライマー、第一工業製薬（株）製）の平均乾燥膜厚50μm にて被覆し、常温で２時間ほど放置してプライマー中の有機溶剤の蒸発とプライマーの硬化を完了させた後、そこをさらに無溶剤型ポリウレタン防食層（パーマガード137 、第一工業製薬（株）製）の平均膜厚2.5mm にて被覆した。また前記電気防食措置では、海中での腐食電位が-900mV vs.SCE 程度になるよう、露出した鋼管杭の表面にAlの犠牲陽極をスポット溶接で取付けた。   After the completion of the TIG welding, a heavy anticorrosion coating was applied to one end of the steel pipe piles not covered with the stainless steel plate, and an anticorrosion measure was applied to the other end. In this heavy anticorrosion coating, the surface of the stainless steel plate that is 50 mm from the TIG welded portion at the boundary of the lap joint covering portion to the covering portion side is ground with sandpaper, and the end of the exposed steel pipe pile connected to this from the grinding portion. Is covered with an average dry film thickness of 50μm of polyurethane primer (330 Primer, Daiichi Kogyo Seiyaku Co., Ltd.) and left at room temperature for about 2 hours to evaporate the organic solvent in the primer and cure the primer. Then, it was further coated with an average film thickness of 2.5 mm of a solventless polyurethane anticorrosive layer (Permguard 137, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.). Further, in the above-described cathodic protection measures, an Al sacrificial anode was attached to the exposed steel pipe pile surface by spot welding so that the corrosion potential in the sea was about -900 mV vs. SCE.

このような防食仕様を施した鋼管杭を、重防食塗装部が海上部、電気防食措置部が海中部に位置するように海岸中に打ち込み、５年間暴露試験を行なった。結果を表３に示す。いずれの部位についても良好な防食性を示した。
（実施例２）
鋼材として炭素鋼からなる鋼管表面の黒皮をブラスト処理で取り除いてなる鋼管杭を用いた。覆装板として、板厚0.4mm のオーステナイト系耐海水ステンレス鋼（表１のS2）の帯板コイルから鋼管杭の寸法に合わせた所定長さだけ巻き戻して切断することにより複数枚切出したものを用いた。 Steel pipe piles with such anti-corrosion specifications were driven into the coast so that the heavy anti-corrosion coating part was located on the sea and the electro-corrosion protection part was located on the sea, and an exposure test was conducted for 5 years. The results are shown in Table 3. All parts showed good anticorrosive properties.
(Example 2)
The steel pipe pile which removed the black skin of the steel pipe surface which consists of carbon steel by blasting as steel materials was used. A cover plate made of 0.4mm thick austenitic seawater-resistant stainless steel (S2 in Table 1) cut out from the strip coil by unwinding and cutting it by a predetermined length according to the dimensions of the steel pipe pile. Was used.

複数の覆装板を順次インダイレクト抵抗スポット溶接により鋼管杭表面に仮止め溶接し（第１の溶接部３形成）、互いの端部を重ね合わせて鋼管杭表面の円周方向に這わせて一周させることにより、鋼管杭の両端部３ｍから内側の領域をステンレス鋼板による重ね継ぎ被覆部となした。前記インダイレクト抵抗スポット溶接は、ステンレス鋼板の端面から50mm以上内側で、かつ、後程行うＴＩＧ溶接の熱影響部と重ならない適宜の位置で行なった。ステンレス鋼板同士の重なり部の幅は30〜50mmとした。ここでのインダイレクト抵抗スポット溶接の施工条件は実施例１と同じINDSP-1 とした。   A plurality of covering plates are sequentially temporarily welded to the surface of the steel pipe pile by indirect resistance spot welding (formation of the first welded portion 3), and the end portions of the covering plates are overlapped in the circumferential direction of the steel pipe pile surface. By making one round, the inner region from both end portions 3m of the steel pipe pile became a lap joint covering portion made of a stainless steel plate. The indirect resistance spot welding was performed at an appropriate position not less than 50 mm inside from the end surface of the stainless steel plate and not overlapping with the heat affected zone of TIG welding performed later. The width of the overlapping part between the stainless steel plates was 30-50 mm. The construction conditions for indirect resistance spot welding here were INDSP-1 as in Example 1.

次いで、前記ステンレス鋼板の重なり部の上板端面と下板表面とがなす段差部（鋼管杭長さ方向に延在）をその全長にわたりＴＩＧ溶接により重ね隅肉溶接し（第２の溶接部４形成）、該段差部の隅に存在していた隙を密封した。さらに、前記重ね継ぎ被覆部の境界においてステンレス鋼板端面と鋼管杭表面とがなす段差部（鋼管杭円周方向に延在）をその全長にわたりＴＩＧ溶接により重ね隅肉溶接し（第３の溶接部５形成）、該段差部の隅に存在していた隙を密封した。ここでのＴＩＧ溶接の施工条件を以下に示す。
・ＴＩＧ溶接（施工条件TIG-2 ）
溶接電流：80Ａ
溶接速度：140mm/min
Arガス流量：10l/min
フィラー：表２のF3
フィラー送り速度：140 mm/min
なお、前記鋼材と同一組成・同一厚さの鋼材試片および前記被覆板と同一組成・同一厚さのステンレス鋼板試片とを用いて同様のＴＩＧ溶接により作製した鋼材試片とステンレス鋼板試片の重ね隅肉溶接継手試料、およびステンレス鋼板試片同士の重ね隅肉溶接継手試料の各溶接部について測定したＣＰＴ値はそれぞれ45℃、55℃であった。このようにして図１に示す構造物構築部材を製造した。 Next, a stepped portion (extending in the length direction of the steel pipe pile) formed by the upper plate end surface and the lower plate surface of the overlapping portion of the stainless steel plate is overlapped and welded by TIG welding over the entire length (second welded portion 4). Formation), the gap that existed in the corner of the step was sealed. Further, a step portion (extending in the circumferential direction of the steel pipe pile) formed by the end face of the stainless steel plate and the surface of the steel pipe pile at the boundary of the lap joint covering part is overlapped and welded by TIG welding over the entire length (third welded part). 5 formation), the gap existing in the corner of the stepped portion was sealed. The construction conditions of TIG welding here are shown below.
・ TIG welding (Construction conditions TIG-2)
Welding current: 80A
Welding speed: 140mm / min
Ar gas flow rate: 10l / min
Filler: F3 in Table 2
Filler feed rate: 140 mm / min
A steel specimen and a stainless steel specimen prepared by the same TIG welding using a steel specimen having the same composition and thickness as the steel and a stainless steel specimen having the same composition and thickness as the covering plate. The CPT values measured for the welds of the lap fillet welded joint samples and the lap fillet welded joint samples of the stainless steel plate specimens were 45 ° C. and 55 ° C., respectively. Thus, the structure building member shown in FIG. 1 was manufactured.

前記ＴＩＧ溶接完了後、実施例１と同様に重防食塗装と電気防食措置を施した。   After completion of the TIG welding, a heavy anticorrosion coating and an anticorrosion measure were applied as in Example 1.

このような防食仕様を施した鋼管杭を、重防食塗装部が海上部、電気防食措置部が海中部に位置するように海岸に打ち込み、５年間暴露試験を行った。結果を表３に示す。いずれも部位についても良好な防食性を示した。
（実施例３）
鋼材として炭素鋼からなる鋼管表面の黒皮をブラスト処理で取り除いてなる鋼管杭を用いた。覆装板として、板厚0.4mm のオーステナイト系耐海水ステンレス鋼（表１のS1）の帯板コイルから鋼管杭の寸法に合わせた所定長さだけ巻き戻して切断することにより複数枚切出したものを用いた。 Steel pipe piles with such anti-corrosion specifications were driven into the coast so that the heavy anti-corrosion coating part was located on the sea and the anti-corrosion measure part was located on the sea, and an exposure test was conducted for 5 years. The results are shown in Table 3. In any case, the anticorrosive property was good for the part.
(Example 3)
The steel pipe pile which removed the black skin of the steel pipe surface which consists of carbon steel by blasting as steel materials was used. A cover plate made of austenite seawater resistant stainless steel (S1 in Table 1) with a thickness of 0.4mm was cut out by unwinding and cutting a predetermined length according to the dimensions of the steel pipe pile. Was used.

複数の覆装板を順次インダイレクト抵抗スポット溶接により鋼管杭表面に仮止め溶接し（第１の溶接部３形成）、互いの端部を重ね合わせて鋼管杭表面の円周方向に這わせて一周させることにより、鋼管杭の両端部３ｍから内側の領域をステンレス鋼板による重ね継ぎ被覆部となした。前記インダイレクト抵抗スポット溶接は、ステンレス鋼板の端面から50mm以上内側で、かつ、後程行うＴＩＧ溶接の熱影響と重ならない適宜の位置で行なった。ステンレス鋼板同士の重なり部の幅は30〜50mmとした。ここでのインダイレクト抵抗スポット溶接の施工条件は実施例１と同じINDSP-1 とした。   A plurality of covering plates are sequentially temporarily welded to the surface of the steel pipe pile by indirect resistance spot welding (formation of the first welded portion 3), and the end portions of the covering plates are overlapped in the circumferential direction of the steel pipe pile surface. By making one round, the inner region from both end portions 3m of the steel pipe pile became a lap joint covering portion made of a stainless steel plate. The indirect resistance spot welding was performed at an appropriate position not less than 50 mm inside from the end face of the stainless steel plate and not overlapping with the thermal effect of TIG welding performed later. The width of the overlapping part between the stainless steel plates was 30-50 mm. The construction conditions for indirect resistance spot welding here were INDSP-1 as in Example 1.

次いで、前記ステンレス鋼板の重なり部の上板端面と下板表面とがなす段差部（鋼管杭長さ方向に延在）をその全長にわたりＴＩＧ溶接により重ね隅肉溶接し（第２の溶接部４の形成）、該段差部の隅に存在していた隙を密封した。さらに、前記重ね継ぎ被覆部の境界においてステンレス鋼板端面と鋼管杭表面とがなす段差部（鋼管杭円周方向に延在）をその全長にわたりＴＩＧ溶接により重ね隅肉溶接し（第３の溶接部５の形成）、該段差部の隅に存在していた隙を密封した。ここでのＴＩＧ溶接の施工条件を以下に示す。
・ＴＩＧ溶接（施工条件TIG-3 ）
溶接電流：60Ａ
溶接速度：140mm/min
Arガス流量：10l/min
フィラー：表２のF1
フィラー送り速度：140mm/min
なお、前記鋼材と同一組成・同一厚さの鋼材試片および前記被覆板と同一組成・同一厚さのステンレス鋼板試片とを用いて同様のＴＩＧ溶接により作製した鋼材試片とステンレス鋼板試片の重ね隅肉溶接継手試料、およびステンレス鋼板試片同士の重ね隅肉溶接継手試料の各溶接部について測定したＣＰＴ値はそれぞれ50℃、60℃であった。このようにして図１に示す構造物構築部材を製造した。 Next, a stepped portion (extending in the length direction of the steel pipe pile) formed by the upper plate end surface and the lower plate surface of the overlapping portion of the stainless steel plate is overlapped and welded by TIG welding over the entire length (second welded portion 4). Formation), and the gap that existed in the corner of the stepped portion was sealed. Further, a step portion (extending in the circumferential direction of the steel pipe pile) formed by the end face of the stainless steel plate and the surface of the steel pipe pile at the boundary of the lap joint covering part is overlapped and welded by TIG welding over the entire length (third welded part). 5), the gap that existed in the corner of the step was sealed. The construction conditions of TIG welding here are shown below.
・ TIG welding (Construction conditions TIG-3)
Welding current: 60A
Welding speed: 140mm / min
Ar gas flow rate: 10l / min
Filler: F1 in Table 2
Filler feed rate: 140mm / min
A steel specimen and a stainless steel specimen prepared by the same TIG welding using a steel specimen having the same composition and thickness as the steel and a stainless steel specimen having the same composition and thickness as the covering plate. The CPT values measured for the welds of the lap fillet welded joint samples and the lap fillet welded joint samples of the stainless steel plate specimens were 50 ° C. and 60 ° C., respectively. Thus, the structure building member shown in FIG. 1 was manufactured.

前記ＴＩＧ溶接完了後、実施例１と同様に重防食塗装と電気防食措置を施した。   After completion of the TIG welding, a heavy anticorrosion coating and an anticorrosion measure were applied as in Example 1.

このような防食仕様を施した鋼管杭を、重防食塗装部が海上部、電気防食措置部が海中部に位置するように海岸中に打ち込み、５年間暴露試験を行なった。結果を表３に示す。いずれの部位についても良好な防食性を示した。
（実施例４）
鋼材として炭素鋼からなる鋼管表面の黒皮をブラスト処理で取り除いてなる鋼管杭を用いた。覆装板として、板厚1.5mm のオーステナイト系耐海水ステンレス鋼（表１のS2）の帯板コイルから鋼管杭の寸法に合わせた所定長さだけ巻き戻して切断することにより複数枚切出したものを用いた。 Steel pipe piles with such anti-corrosion specifications were driven into the coast so that the heavy anti-corrosion coating part was located on the sea and the electro-corrosion protection part was located on the sea, and an exposure test was conducted for 5 years. The results are shown in Table 3. All parts showed good anticorrosive properties.
(Example 4)
The steel pipe pile which removed the black skin of the steel pipe surface which consists of carbon steel by blasting as steel materials was used. A cover plate made of austenite seawater resistant stainless steel (S2 in Table 1) with a thickness of 1.5mm. Was used.

複数の覆装板を順次インダイレクト抵抗スポット溶接により鋼管杭表面に仮止め溶接し（第１の溶接部３の形成）、互いの端部を重ね合わせて鋼管杭表面の円周方向に這わせて一周させることにより、鋼管杭の両端部３ｍから内側の領域をステンレス鋼板による重ね継ぎ被覆部となした。前記インダイレクト抵抗スポット溶接は、ステンレス鋼板の端面から50mm以上内側で、かつ、後程行うＴＩＧ溶接の熱影響と重ならない適宜の位置で行なった。ステンレス鋼板同士の重なり部の幅は30〜50mmとした。また、該重なり部の外側の該重なり部に近い位置でステンレス鋼板下板と鋼管杭とをインダイレクト抵抗シーム溶接により仮止め溶接した（第１の溶接部８の形成）。ここでのインダイレクト抵抗スポット溶接の施工条件は実施例１と同じINDSP-1 とした。また、インダイレクト抵抗シーム溶接の施工条件は以下に示す。
・インダイレクト抵抗シーム溶接（施工条件INDSM-1 ）
溶接電流：7970Ａ
ローラ電極寸法：溶接側150mm φ×３mm
非溶接側（アース側）150 mmφ×16mm
加圧力：溶接側2.0kN/mm2 、非溶接側（アース側）4.8kN/mm2
溶接速度：2.0 ｍ/min
次いで、前記ステンレス鋼板の重なり部の上板端面と下板表面とがなす段差部（鋼管杭長さ方向に延在）をその全長にわたりＴＩＧ溶接により重ね隅肉溶接し（第２の溶接部４の形成）、該段差部の隅に存在していた隙を密封した。さらに、前記重ね継ぎ被覆部の境界においてステンレス鋼板端面と鋼管杭表面とがなす段差部（鋼管杭円周方向に延在）をその全長にわたりＴＩＧ溶接により重ね隅肉溶接し（第３の溶接部５の形成）、該段差部の隅に存在していた隙を密封した。ここでのＴＩＧ溶接の施工条件を以下に示す。
・ＴＩＧ溶接（施工条件TIG-4 ）
溶接電流：115 Ａ
溶接速度：350mm/min
Arガス流量：10l/min
フィラー：表２のF2
フィラー送り速度：350mm/min
なお、前記鋼材と同一組成・同一厚さの鋼材試片および前記被覆板と同一組成・同一厚さのステンレス鋼板試片とを用いて同様のＴＩＧ溶接により作製した鋼材試片とステンレス鋼板試片の重ね隅肉溶接継手試料、およびステンレス鋼板試片同士の重ね隅肉溶接継手試料の各溶接部について測定したＣＰＴ値はそれぞれ45℃、55℃であった。このようにして図９に示す構造物構築部材を製造した。 A plurality of covering plates are sequentially temporarily welded to the surface of the steel pipe pile by indirect resistance spot welding (formation of the first welded portion 3), and the ends of each of the covering plates are overlapped in the circumferential direction on the surface of the steel pipe pile. The inner region from both end portions 3m of the steel pipe pile became a lap joint covering portion made of a stainless steel plate. The indirect resistance spot welding was performed at an appropriate position not less than 50 mm inside from the end face of the stainless steel plate and not overlapping with the thermal effect of TIG welding performed later. The width of the overlapping part between the stainless steel plates was 30-50 mm. Moreover, the stainless steel plate lower plate and the steel pipe pile were temporarily fixed by indirect resistance seam welding at a position near the overlapping portion outside the overlapping portion (formation of the first welded portion 8). The construction conditions for indirect resistance spot welding here were INDSP-1 as in Example 1. The construction conditions for indirect resistance seam welding are shown below.
・ Indirect resistance seam welding (Construction conditions INDSM-1)
Welding current: 7970A
Roller electrode dimensions: Welded side 150mm φ × 3mm
Non-welded side (ground side) 150 mmφ × 16mm
Pressure: Welding side 2.0 kN / mm 2, the non-welded side (ground side) 4.8kN / mm 2
Welding speed: 2.0 m / min
Next, a stepped portion (extending in the length direction of the steel pipe pile) formed by the upper plate end surface and the lower plate surface of the overlapping portion of the stainless steel plate is overlapped and welded by TIG welding over the entire length (second welded portion 4). Formation), and the gap that existed in the corner of the stepped portion was sealed. Further, a step portion (extending in the circumferential direction of the steel pipe pile) formed by the end face of the stainless steel plate and the surface of the steel pipe pile at the boundary of the lap joint covering part is overlapped and welded by TIG welding over the entire length (third welded part). 5), the gap that existed in the corner of the step was sealed. The construction conditions of TIG welding here are shown below.
・ TIG welding (Construction conditions TIG-4)
Welding current: 115 A
Welding speed: 350mm / min
Ar gas flow rate: 10l / min
Filler: F2 in Table 2
Filler feed rate: 350mm / min
A steel specimen and a stainless steel specimen prepared by the same TIG welding using a steel specimen having the same composition and thickness as the steel and a stainless steel specimen having the same composition and thickness as the covering plate. The CPT values measured for the welds of the lap fillet welded joint samples and the lap fillet welded joint samples of the stainless steel plate specimens were 45 ° C. and 55 ° C., respectively. In this way, the structure building member shown in FIG. 9 was manufactured.

前記ＴＩＧ溶接完了後、実施例１と同様に重防食塗装と電気防食措置を施した。   After completion of the TIG welding, a heavy anticorrosion coating and an anticorrosion measure were applied as in Example 1.

このような防食仕様を施した鋼管杭を、重防食塗装部が海上部、電気防食措置部が海中部に位置するように海岸中に打ち込み、５年間暴露試験を行なった。結果を表３に示す。いずれの部位についても良好な防食性を示した。
（実施例５）
鋼材として炭素鋼からなる鋼管表面の黒皮をブラスト処理で取り除いてなる鋼管杭を用いた。覆装板として、板厚0.4mm のオーステナイト系耐海水ステンレス鋼（表１のS1）の帯板コイルから鋼管杭の寸法に合わせて所定の長さだけを巻き戻して切断することにより複数枚切出したものを用いた。 Steel pipe piles with such anti-corrosion specifications were driven into the coast so that the heavy anti-corrosion coating part was located on the sea and the electro-corrosion protection part was located on the sea, and an exposure test was conducted for 5 years. The results are shown in Table 3. All parts showed good anticorrosive properties.
(Example 5)
The steel pipe pile which removed the black skin of the steel pipe surface which consists of carbon steel by blasting as steel materials was used. As a covering plate, a plurality of sheets are cut out by unwinding and cutting only a predetermined length according to the dimensions of the steel pipe pile from the strip coil of 0.4mm thick austenitic seawater resistant stainless steel (S1 in Table 1) Used.

複数の覆装板を順次インダイレクト抵抗スポット溶接により鋼管杭表面に仮止め溶接し（第１の溶接部３の形成）、互いの端部を重ね合わせて鋼管杭表面の円周方向に這わせて一周させることにより、鋼管杭の両端部３ｍから内側の領域をステンレス鋼板による重ね継ぎ被覆部となした。前記インダイレクト抵抗スポット溶接は、ステンレス鋼板の端面から50mm以上内側で、かつ、後程行うＴＩＧ溶接の熱影響と重ならない適宜の位置で行なった。ステンレス鋼板同士の重なり部の幅は50〜70mmとした。   A plurality of covering plates are sequentially temporarily welded to the surface of the steel pipe pile by indirect resistance spot welding (formation of the first welded portion 3), and the ends of each of the covering plates are overlapped in the circumferential direction on the surface of the steel pipe pile. The inner region from both end portions 3m of the steel pipe pile became a lap joint covering portion made of stainless steel. The indirect resistance spot welding was performed at an appropriate position not less than 50 mm inside from the end face of the stainless steel plate and not overlapping with the thermal effect of TIG welding performed later. The width of the overlapping part between the stainless steel plates was 50 to 70 mm.

さらに、前記ステンレス鋼板の重なり部の上板端面と下板端面とが成す段差部（鋼管杭長さ方向に延在）をその全長方向に亘って仮固定するために、前記段差部の両側に、段差部から15mmの位置に、溶接中心間距離15mmの間隔でインダイレクト抵抗スポット溶接を施した（第１の溶接部６および第４の溶接部７の形成）。ここでのこれらのインダイレクト抵抗スポット溶接の施工条件を以下に示す。
・インダイレクト抵抗スポット溶接（INDSP-2 ）
溶接電流：6500Ａ
電極径：溶接側、非溶接側（アース側）とも16mmφ
加圧力：溶接側、非溶接側（アース側）とも2.0kN/mm2
電極間距離：200mm
次いで、前記段差部をその全長方向に亘りＴＩＧ溶接により重ね隅肉溶接し（第２の溶接部４の形成）、該段差部の隅に存在していた隙間を密封した。さらに、前記重ね継ぎ溶接部の境界においてステンレス鋼板端面と鋼管杭表面とが成す段差部（鋼管杭円周方向に延在）をその全長に亘りＴＩＧ溶接により重ね隅肉溶接し（第３の溶接部５の形成）、該段差部の隅に存在していた隙間を密封した。ここでのＴＩＧ溶接の施工条件は実施例１と同じTIG-1 とした。 Furthermore, in order to temporarily fix the step portion (extending in the length direction of the steel pipe pile) formed by the upper plate end surface and the lower plate end surface of the overlapping portion of the stainless steel plate, on both sides of the step portion. Then, indirect resistance spot welding was performed at a position 15 mm from the stepped portion at a distance of 15 mm between the weld centers (formation of the first welded portion 6 and the fourth welded portion 7). The construction conditions of these indirect resistance spot weldings are shown below.
・ Indirect resistance spot welding (INDSP-2)
Welding current: 6500A
Electrode diameter: 16mmφ for both welded side and non-welded side (ground side)
Pressure: 2.0kN / mm 2 for both welded side and non-welded side (ground side)
Distance between electrodes: 200mm
Next, the stepped portion was overlapped and fillet welded by TIG welding over the entire length direction (formation of the second welded portion 4), and the gap existing at the corner of the stepped portion was sealed. Further, the step portion (extending in the circumferential direction of the steel pipe pile) formed by the end face of the stainless steel plate and the surface of the steel pipe pile at the boundary of the lap joint weld is overlapped by TIG welding over the entire length (third welding). Formation of the portion 5), the gap existing in the corner of the step portion was sealed. The construction conditions for TIG welding here were the same as TIG-1 in Example 1.

なお、前記鋼材と同一組成・同一厚さの鋼材試片および前記被覆板と同一組成・同一厚さのステンレス鋼板試片とを用いて同様のＴＩＧ溶接により作製した鋼材試片とステンレス鋼板試片の重ね隅肉溶接継手試料、およびステンレス鋼板試片同士の重ね隅肉溶接継手試料の各溶接部について測定したＣＰＴ値はそれぞれ50℃、60℃であった。このようにして図６に示す構造物構築部材を製造した。   A steel specimen and a stainless steel specimen prepared by the same TIG welding using a steel specimen having the same composition and thickness as the steel and a stainless steel specimen having the same composition and thickness as the covering plate. The CPT values measured for the welds of the lap fillet welded joint samples and the lap fillet welded joint samples of the stainless steel plate specimens were 50 ° C. and 60 ° C., respectively. In this way, the structure building member shown in FIG. 6 was manufactured.

前記ＴＩＧ溶接完了後、実施例１と同様に重防食塗装と電気防食措置を施した。   After completion of the TIG welding, a heavy anticorrosion coating and an anticorrosion measure were applied as in Example 1.

このような防食仕様を施した鋼管杭を、重防食塗装部が海上部、電気防食措置部が海中部に位置するように海岸中に打ち込み、５年間暴露試験を行なった。結果を表３に示す。いずれの部位についても良好な防食性を示した。
（実施例６）
鋼材として炭素鋼からなる鋼管表面の黒皮をブラスト処理で取り除いてなる鋼管杭を用いた。覆装板として、板厚0.4mm のオーステナイト系耐海水ステンレス鋼（表１のS1）の帯板コイルから鋼管杭の寸法に合わせて所定の長さだけを巻き戻して切断することにより複数枚切出したものを用いた。 Steel pipe piles with such anti-corrosion specifications were driven into the coast so that the heavy anti-corrosion coating part was located on the sea and the electro-corrosion protection part was located on the sea, and an exposure test was conducted for 5 years. The results are shown in Table 3. All parts showed good anticorrosive properties.
(Example 6)
The steel pipe pile which removed the black skin of the steel pipe surface which consists of carbon steel by blasting as steel materials was used. As a covering plate, a plurality of sheets are cut out by unwinding and cutting only a predetermined length according to the dimensions of the steel pipe pile from the strip coil of 0.4mm thick austenitic seawater resistant stainless steel (S1 in Table 1) Used.

複数の覆装板を順次インダイレクト抵抗スポット溶接により鋼管杭表面に仮止め溶接し（第１の溶接部３の形成）、互いの端部を重ね合わせて鋼管杭表面の円周方向に這わせて一周させることにより、鋼管杭の両端部３ｍから内側の領域をステンレス鋼板による重ね継ぎ被覆部となした。前記インダイレクト抵抗スポット溶接は、ステンレス鋼板の端面から50mm以上内側で、かつ、後程行うＴＩＧ溶接の熱影響と重ならない適宜の位置で行なった。ステンレス鋼板同士の重なり部の幅は50〜70mmとした。また、該重なり部の内側のステンレス鋼板下板の端部近傍と鋼管杭とをインダイレクト抵抗シーム溶接により仮止め溶接した（第１の溶接部８の形成）。ここでのインダイレクト抵抗スポット溶接の施工条件は実施例１と同じINDSP-1 とした。また、インダイレクト抵抗シーム溶接の施工条件は以下に示す。
・インダイレクト抵抗シーム溶接（施工条件INDSM-2 ）
溶接電流：5000Ａ
ローラ電極寸法：溶接側 150mm φ×３mm
非溶接側（アース側） 150mm φ×16mm
加圧力：溶接側2.0kN/mm2 、非溶接側（アース側）4.8kN/mm2
溶接速度：2.0 ｍ/min
次いで、前記段差部をその全長方向に亘りＴＩＧ溶接により重ね隅肉溶接し（第２の溶接部４の形成）、該段差部の隅に存在していた隙間を密封した。さらに、前記重ね継ぎ溶接部の境界においてステンレス鋼板端面と鋼管杭表面とが成す段差部（鋼管杭円周方向に延在）をその全長に亘りＴＩＧ溶接により重ね隅肉溶接し（第３の溶接部５の形成）、該段差部の隅に存在していた隙間を密封した。ここでのＴＩＧ溶接の施工条件は実施例１と同じTIG-1 とした。 A plurality of covering plates are sequentially temporarily welded to the surface of the steel pipe pile by indirect resistance spot welding (formation of the first welded portion 3), and the ends of each of the covering plates are overlapped in the circumferential direction on the surface of the steel pipe pile. The inner region from both end portions 3m of the steel pipe pile became a lap joint covering portion made of a stainless steel plate. The indirect resistance spot welding was performed at an appropriate position not less than 50 mm inside from the end face of the stainless steel plate and not overlapping with the thermal effect of TIG welding performed later. The width of the overlapping part between the stainless steel plates was 50 to 70 mm. Moreover, the edge part vicinity of the stainless steel plate lower plate inside this overlap part, and the steel pipe pile were temporarily fixed-welded by indirect resistance seam welding (formation of the 1st welding part 8). The construction conditions for indirect resistance spot welding here were INDSP-1 as in Example 1. The construction conditions for indirect resistance seam welding are shown below.
・ Indirect resistance seam welding (Construction conditions INDSM-2)
Welding current: 5000A
Roller electrode dimensions: Welded side 150mm φ × 3mm
Non-welded side (ground side) 150mm φ × 16mm
Pressure: Welding side 2.0 kN / mm 2, the non-welded side (ground side) 4.8kN / mm 2
Welding speed: 2.0 m / min
Next, the stepped portion was overlapped and fillet welded by TIG welding over the entire length direction (formation of the second welded portion 4), and the gap existing at the corner of the stepped portion was sealed. Further, the step portion (extending in the circumferential direction of the steel pipe pile) formed by the end face of the stainless steel plate and the surface of the steel pipe pile at the boundary of the lap joint weld is overlapped by TIG welding over the entire length (third welding). Formation of the portion 5), the gap existing in the corner of the step portion was sealed. The construction conditions for TIG welding here were the same as TIG-1 in Example 1.

なお、前記鋼材と同一組成・同一厚さの鋼材試片および前記被覆板と同一組成・同一厚さのステンレス鋼板試片とを用いて同様のＴＩＧ溶接により作製した鋼材試片とステンレス鋼板試片の重ね隅肉溶接継手試料、およびステンレス鋼板試片同士の重ね隅肉溶接継手試料の各溶接部について測定したＣＰＴ値はそれぞれ50℃、60℃であった。このようにして図３に示す構造物構築部材を製造した。   A steel specimen and a stainless steel specimen prepared by the same TIG welding using a steel specimen having the same composition and thickness as the steel and a stainless steel specimen having the same composition and thickness as the covering plate. The CPT values measured for the welds of the lap fillet welded joint samples and the lap fillet welded joint samples of the stainless steel plate specimens were 50 ° C. and 60 ° C., respectively. In this way, the structure building member shown in FIG. 3 was manufactured.

前記ＴＩＧ溶接完了後、実施例１と同様に重防食塗装と電気防食措置を施した。   After completion of the TIG welding, a heavy anticorrosion coating and an anticorrosion measure were applied as in Example 1.

このような防食仕様を施した鋼管杭を、重防食塗装部が海上部、電気防食措置部が海中部に位置するように海岸中に打ち込み、５年間暴露試験を行なった。結果を表３に示す。いずれの部位についても良好な防食性を示した。
（実施例７）
鋼材として炭素鋼からなる鋼管表面の黒皮をブラスト処理で取り除いてなる鋼管杭を用いた。覆装板として、板厚0.4mm のオーステナイト系耐海水ステンレス鋼（表１のS1）の帯板コイルから鋼管杭の寸法に合わせて所定の長さだけを巻き戻して切断することにより複数枚切出したものを用いた。 Steel pipe piles with such anti-corrosion specifications were driven into the coast so that the heavy anti-corrosion coating part was located on the sea and the electro-corrosion protection part was located on the sea, and an exposure test was conducted for 5 years. The results are shown in Table 3. All parts showed good anticorrosive properties.
(Example 7)
The steel pipe pile which removed the black skin of the steel pipe surface which consists of carbon steel by blasting as steel materials was used. As a covering plate, a plurality of sheets are cut out by unwinding and cutting only a predetermined length according to the dimensions of the steel pipe pile from the strip coil of 0.4mm thick austenitic seawater resistant stainless steel (S1 in Table 1) Used.

複数の覆装板を順次インダイレクト抵抗スポット溶接により鋼管杭表面に仮止め溶接し（第１の溶接部３の形成）、互いの端部を重ね合わせて鋼管杭表面の円周方向に這わせて一周させることにより、鋼管杭の両端部３ｍから内側の領域をステンレス鋼板による重ね継ぎ被覆部となした。前記インダイレクト抵抗スポット溶接は、ステンレス鋼板の端面から50mm以上内側で、かつ、後程行うＴＩＧ溶接の熱影響と重ならない適宜の位置で行なった。ステンレス鋼板同士の重なり部の幅は50〜70mmとした。また、該重なり部の内側のステンレス鋼板下板の端部近傍と鋼管杭とをインダイレクト抵抗シーム溶接により仮止め溶接した（第１の溶接部８の形成）。ここでのインダイレクト抵抗スポット溶接の施工条件は実施例１と同じINDSP-1 とした。また、インダイレクト抵抗シーム溶接の施工条件は実施例６と同じINDSM-2 とした。   A plurality of covering plates are sequentially temporarily welded to the surface of the steel pipe pile by indirect resistance spot welding (formation of the first welded portion 3), and the ends of each of the covering plates are overlapped in the circumferential direction on the surface of the steel pipe pile. The inner region from both end portions 3m of the steel pipe pile became a lap joint covering portion made of stainless steel. The indirect resistance spot welding was performed at an appropriate position not less than 50 mm inside from the end face of the stainless steel plate and not overlapping with the thermal effect of TIG welding performed later. The width of the overlapping part between the stainless steel plates was 50 to 70 mm. Moreover, the edge part vicinity of the stainless steel plate lower plate inside this overlap part, and the steel pipe pile were temporarily fixed-welded by indirect resistance seam welding (formation of the 1st welding part 8). The construction conditions for indirect resistance spot welding here were INDSP-1 as in Example 1. The construction conditions for indirect resistance seam welding were the same as INDSM-2 in Example 6.

また、前記ステンレス鋼板の重なり部（鋼管杭長さ方向に延在）をその全長方向に亘って仮固定するために、ステンレス鋼板の重なり部の上板端面と下板端面が成す段差部から重なり部内側に15mmの位置に、溶接中心間距離15mmの間隔でインダイレクト抵抗スポット溶接を施した（第４の溶接部７の形成）。ここでのインダイレクト抵抗スポット溶接の施工条件は、実施例５と同じINDSP-2 とした。   Further, in order to temporarily fix the overlapping portion of the stainless steel plate (extending in the length direction of the steel pipe pile) over the entire length direction, the overlapping portion of the stainless steel plate overlaps with the step portion formed by the upper plate end surface and the lower plate end surface. Indirect resistance spot welding was performed at a position of 15 mm between the weld centers at a position of 15 mm inside the part (formation of the fourth weld 7). The indirect resistance spot welding conditions here were the same as INDSP-2 in Example 5.

次いで、前記段差部をその全長方向に亘りＴＩＧ溶接により重ね隅肉溶接し（第２の溶接部４の形成）、該段差部の隅に存在していた隙間を密封した。さらに、前記重ね継ぎ溶接部の境界においてステンレス鋼板端面と鋼管杭表面とが成す段差部（鋼管杭円周方向に延在）をその全長に亘りＴＩＧ溶接により重ね隅肉溶接し（第３の溶接部５の形成）、該段差部の隅に存在していた隙間を密封した。ここでのＴＩＧ溶接の施工条件は実施例１と同じTIG-1 とした。   Next, the stepped portion was overlapped and fillet welded by TIG welding over the entire length direction (formation of the second welded portion 4), and the gap existing at the corner of the stepped portion was sealed. Further, the step portion (extending in the circumferential direction of the steel pipe pile) formed by the end face of the stainless steel plate and the surface of the steel pipe pile at the boundary of the lap joint weld is overlapped by TIG welding over the entire length (third welding). Formation of the portion 5), the gap existing in the corner of the step portion was sealed. The construction conditions for TIG welding here were the same as TIG-1 in Example 1.

なお、前記鋼材と同一組成・同一厚さの鋼材試片および前記被覆板と同一組成・同一厚さのステンレス鋼板試片とを用いて同様のＴＩＧ溶接により作製した鋼材試片とステンレス鋼板試片の重ね隅肉溶接継手試料、およびステンレス鋼板試片同士の重ね隅肉溶接継手試料の各溶接部について測定したＣＰＴ値はそれぞれ50℃、60℃であった。このようにして図７に示す構造物構築部材を製造した。   A steel specimen and a stainless steel specimen prepared by the same TIG welding using a steel specimen having the same composition and thickness as the steel and a stainless steel specimen having the same composition and thickness as the covering plate. The CPT values measured for the welds of the lap fillet welded joint samples and the lap fillet welded joint samples of the stainless steel plate specimens were 50 ° C. and 60 ° C., respectively. In this way, the structure building member shown in FIG. 7 was manufactured.

前記ＴＩＧ溶接完了後、実施例１と同様に重防食塗装と電気防食措置を施した。   After completion of the TIG welding, a heavy anticorrosion coating and an anticorrosion measure were applied as in Example 1.

このような防食仕様を施した鋼管杭を、重防食塗装部が海上部、電気防食措置部が海中部に位置するように海岸中に打ち込み、５年間暴露試験を行なった。結果を表３に示す。いずれの部位についても良好な防食性を示した。
（比較例１）
鋼材として炭素鋼からなる鋼管表面の黒皮をブラスト処理で取り除いてなる鋼管杭を用いた。覆装板として、板厚0.4mm のオーステナイト系耐海水ステンレス鋼（表１のS1）の帯板コイルから鋼管杭の寸法に合わせた所定長さだけ巻き戻して切断することにより複数枚切出したものを用いた。 Steel pipe piles with such anti-corrosion specifications were driven into the coast so that the heavy anti-corrosion coating part was located on the sea and the electro-corrosion protection part was located on the sea, and an exposure test was conducted for 5 years. The results are shown in Table 3. All parts showed good anticorrosive properties.
(Comparative Example 1)
The steel pipe pile which removed the black skin of the steel pipe surface which consists of carbon steel by blasting as steel materials was used. A cover plate made of austenite seawater resistant stainless steel (S1 in Table 1) with a thickness of 0.4mm was cut out by unwinding and cutting a predetermined length according to the dimensions of the steel pipe pile. Was used.

複数の覆装板を順次インダイレクト抵抗スポット溶接により鋼管杭表面に仮止め溶接し、互いの端部を重ね合わせて鋼管杭表面の円周方向に這わせて一周させることにより、鋼管杭の両端部３ｍから内側の領域をステンレス鋼板による重ね継ぎ被覆部となした。前記インダイレクト抵抗スポット溶接は、ステンレス鋼板の端面から50mm以上内側の適宜の位置で行なった。ステンレス鋼板同士の重なり部の幅は30〜50mmとした。また、該重なり部の外側の該重なり部に近い位置でステンレス鋼板と鋼管杭とをインダイレクト抵抗シーム溶接により仮止め溶接した。ここでのインダイレクト抵抗スポット溶接、インダイレクト抵抗シーム溶接の施工条件はそれぞれ前記施工条件INDSP-1 、INDSM-1 とした。   Both ends of the steel pipe pile are welded to the surface of the steel pipe pile by indirect resistance spot welding in sequence, and the ends of each cover plate are overlapped with each other and rolled around in the circumferential direction of the steel pipe pile surface. The inner region from the portion 3m was a lap joint covering portion made of a stainless steel plate. The indirect resistance spot welding was performed at an appropriate position 50 mm or more inside from the end face of the stainless steel plate. The width of the overlapping part between the stainless steel plates was 30-50 mm. Further, the stainless steel plate and the steel pipe pile were temporarily welded by indirect resistance seam welding at a position near the overlapping portion outside the overlapping portion. The construction conditions for indirect resistance spot welding and indirect resistance seam welding here were the construction conditions INDSP-1 and INDSM-1, respectively.

次いで、前記ステンレス鋼板の重なり部の上板端面と下板表面とがなす段差部（鋼管杭長さ方向に延在）をその全長にわたりＴＩＧ溶接により重ね隅肉溶接し、該段差部の隅に存在していた隙を密封した。さらに、前記重ね継ぎ被覆部の境界においてステンレス鋼板端面と鋼管杭表面とがなす段差部（鋼管杭円周方向に延在）をその全長にわたりＴＩＧ溶接により重ね隅肉溶接し、該段差部の隅に存在していた隙を密封した。ここでのＴＩＧ溶接の施工条件を以下に示す。
・ＴＩＧ溶接（施工条件TIG-X1）
溶接電流：150 Ａ
溶接速度：600mm/min
Arガス流量：10l/min
フィラー：使用せず
なお、前記鋼材と同一組成・同一厚さの鋼材試片および前記被覆板と同一組成・同一厚さのステンレス鋼板試片とを用いて同様のＴＩＧ溶接により作製した鋼材試片とステンレス鋼板試片の重ね隅肉溶接継手試料、およびステンレス鋼板試片同士の重ね隅肉溶接継手試料の各溶接部について測定したＣＰＴ値はそれぞれ20℃、25℃であった。 Next, the step portion (extending in the length direction of the steel pipe pile) formed by the upper plate end surface and the lower plate surface of the overlapping portion of the stainless steel plate is overlapped and welded by TIG welding over the entire length, and is formed at the corner of the step portion. The gap that existed was sealed. Further, a step portion (extending in the circumferential direction of the steel pipe pile) formed by the end face of the stainless steel plate and the steel pipe pile surface at the boundary of the lap joint covering portion is overlapped by TIG welding over the entire length thereof, and a corner of the step portion is formed. The gap that existed in was sealed. The construction conditions of TIG welding here are shown below.
・ TIG welding (Construction conditions TIG-X1)
Welding current: 150 A
Welding speed: 600mm / min
Ar gas flow rate: 10l / min
Filler: Not used, but a steel specimen having the same composition and thickness as that of the steel material and a stainless steel specimen having the same composition and thickness as that of the covering plate and the same TIG welding. The CPT values measured for the welds of the lap fillet welded joint sample of the stainless steel plate and the lap fillet welded joint sample of the stainless steel plate specimens were 20 ° C. and 25 ° C., respectively.

前記ＴＩＧ溶接完了後、実施例１と同様にして、該両端部の一方に重防食塗装、他方に電気防食措置を施した。   After completion of the TIG welding, in the same manner as in Example 1, a heavy anticorrosion coating was applied to one of the both ends, and an anticorrosion measure was applied to the other.

このような防食仕様を施した鋼管杭を、重防食塗装部が海上部、電気防食措置部が海中部に位置するように海岸中に打ち込み、５年間暴露試験を行なった。結果を表３に示す。溶接ビード部およびその周囲の熱影響部に孔食が発生した。
（比較例２）
鋼材として炭素鋼からなる鋼管表面の黒皮をブラスト処理で取り除いてなる鋼管杭を用いた。覆装板として、板厚0.4mm のオーステナイト系耐海水ステンレス鋼（表１のS1）の帯板コイルから鋼管杭の寸法に合わせた所定長さだけ巻き戻して切断することにより複数枚切出したものを用いた。 Steel pipe piles with such anti-corrosion specifications were driven into the coast so that the heavy anti-corrosion coating part was located on the sea and the electro-corrosion protection part was located on the sea, and an exposure test was conducted for 5 years. The results are shown in Table 3. Pitting corrosion occurred at the weld bead and the surrounding heat affected zone.
(Comparative Example 2)
The steel pipe pile which removed the black skin of the steel pipe surface which consists of carbon steel by blasting as steel materials was used. A cover plate made of austenite seawater resistant stainless steel (S1 in Table 1) with a thickness of 0.4mm was cut out by unwinding and cutting a predetermined length according to the dimensions of the steel pipe pile. Was used.

複数の覆装板を順次インダイレクト抵抗スポット溶接により鋼管杭表面に仮止め溶接し、互いの端部を重ね合わせて鋼管杭表面の円周方向に這わせて一周させることにより、鋼管杭の両端部３ｍから内側の領域をステンレス鋼板による重ね継ぎ被覆部となした。前記インダイレクト抵抗スポット溶接は、ステンレス鋼板の端面から50mm以上内側の適宜の位置で行なった。ステンレス鋼板同士の重なり部の幅は30〜50mmとした。また、該重なり部の外側の該重なり部に近い位置でステンレス鋼板と鋼管杭とをインダイレクト抵抗シーム溶接により仮止め溶接した。ここでのインダイレクト抵抗スポット溶接、インダイレクト抵抗シーム溶接の施工条件はそれぞれ前記施工条件INDSP-1 、INDSM-1 とした。   Both ends of the steel pipe pile are welded to the surface of the steel pipe pile by indirect resistance spot welding in sequence, and the ends of each cover plate are overlapped with each other and rolled around in the circumferential direction of the steel pipe pile surface. The inner region from the portion 3m was a lap joint covering portion made of a stainless steel plate. The indirect resistance spot welding was performed at an appropriate position 50 mm or more inside from the end face of the stainless steel plate. The width of the overlapping part between the stainless steel plates was 30-50 mm. Further, the stainless steel plate and the steel pipe pile were temporarily welded by indirect resistance seam welding at a position near the overlapping portion outside the overlapping portion. The construction conditions for indirect resistance spot welding and indirect resistance seam welding here were the construction conditions INDSP-1 and INDSM-1, respectively.

次いで、前記ステンレス鋼板の重なり部の上板端面と下板表面とがなす段差部（鋼管杭長さ方向に延在）をその全長にわたりＴＩＧ溶接により重ね隅肉溶接し、該段差部の隅に存在していた隙を密封した。さらに、前記重ね継ぎ被覆部の境界においてステンレス鋼板端面と鋼管杭表面とがなす段差部（鋼管杭円周方向に延在）をその全長にわたりＴＩＧ溶接により重ね隅肉溶接し、該段差部の隅に存在していた隙を密封した。ここでのＴＩＧ溶接の施工条件を以下に示す。
・ＴＩＧ溶接（施工条件TIG-X2）
溶接電流：190 Ａ
溶接速度：400mm/min
Arガス流量：10l/min
フィラー：表２のF4
フィラー送り速度：400mm/min
なお、前記鋼材と同一組成・同一厚さの鋼材試片および前記被覆板と同一組成・同一厚さのステンレス鋼板試片とを用いて同様のＴＩＧ溶接により作製した鋼材試片とステンレス鋼板試片の重ね隅肉溶接継手試料、およびステンレス鋼板試片同士の重ね隅肉溶接継手試料の各溶接部について測定したＣＰＴ値はそれぞれ30℃、30℃であった。 Next, the step portion (extending in the length direction of the steel pipe pile) formed by the upper plate end surface and the lower plate surface of the overlapping portion of the stainless steel plate is overlapped and welded by TIG welding over the entire length, and is formed at the corner of the step portion. The gap that existed was sealed. Further, a step portion (extending in the circumferential direction of the steel pipe pile) formed by the end face of the stainless steel plate and the steel pipe pile surface at the boundary of the lap joint covering portion is overlapped by TIG welding over the entire length thereof, and a corner of the step portion is formed. The gap that existed in was sealed. The construction conditions of TIG welding here are shown below.
・ TIG welding (Construction conditions TIG-X2)
Welding current: 190 A
Welding speed: 400mm / min
Ar gas flow rate: 10l / min
Filler: F4 in Table 2
Filler feed rate: 400mm / min
A steel specimen and a stainless steel specimen prepared by the same TIG welding using a steel specimen having the same composition and thickness as the steel and a stainless steel specimen having the same composition and thickness as the covering plate. The CPT values measured for the welds of the lap fillet welded joint samples and the lap fillet welded joint samples of the stainless steel plate specimens were 30 ° C. and 30 ° C., respectively.

前記ＴＩＧ溶接完了後、実施例１と同様にして、該両端部の一方に重防食塗装、他方に電気防食措置を施した。   After completion of the TIG welding, in the same manner as in Example 1, a heavy anticorrosion coating was applied to one of the both ends, and an anticorrosion measure was applied to the other.

このような防食仕様を施した鋼管杭を、重防食塗装部が海上部、電気防食措置部が海中部に位置するように海岸中に打ち込み、５年間暴露試験を行なった。結果を表３に示す。溶接ビード部には孔食が発生しなかったものの、その周囲の熱影響部には孔食が発生した。
（比較例３）
鋼材として炭素鋼からなる鋼管表面の黒皮をブラスト処理で取り除いてなる鋼管杭を用いた。覆装板として、板厚0.4mm のオーステナイト系ステンレス鋼（表１のS3）の帯板コイルから鋼管杭の寸法に合わせた所定長さだけ巻き戻して切断することにより複数枚切出したものを用いた。 Steel pipe piles with such anti-corrosion specifications were driven into the coast so that the heavy anti-corrosion coating part was located on the sea and the electro-corrosion protection part was located on the sea, and an exposure test was conducted for 5 years. The results are shown in Table 3. Although pitting corrosion did not occur in the weld bead portion, pitting corrosion occurred in the surrounding heat affected zone.
(Comparative Example 3)
The steel pipe pile which removed the black skin of the steel pipe surface which consists of carbon steel by blasting as steel materials was used. As the covering plate, a strip of austenitic stainless steel (S3 in Table 1) with a thickness of 0.4mm, which is cut out by unwinding and cutting a predetermined length according to the dimensions of the steel pipe pile, is used. It was.

複数の覆装板を順次インダイレクト抵抗スポット溶接により鋼管杭表面に仮止め溶接し、互いの端部を重ね合わせて鋼管杭表面の円周方向に這わせて一周させることにより、鋼管杭の両端部３ｍから内側の領域をステンレス鋼板による重ね継ぎ被覆部となした。前記インダイレクト抵抗スポット溶接は、ステンレス鋼板の端面から50mm以上内側の適宜の位置で行なった。ステンレス鋼板同士の重なり部の幅は30〜50mmとした。また、該重なり部の外側の該重なり部に近い位置でステンレス鋼板と鋼管杭とをインダイレクト抵抗シーム溶接により仮止め溶接した。ここでのインダイレクト抵抗スポット溶接、インダイレクト抵抗シーム溶接の施工条件はそれぞれ前記施工条件INDSP-1 、INDSM-1 とした。   Both ends of the steel pipe pile are welded to the surface of the steel pipe pile by indirect resistance spot welding in sequence, and the ends of each cover plate are overlapped with each other and rolled around in the circumferential direction of the steel pipe pile surface. The inner region from the portion 3m was a lap joint covering portion made of a stainless steel plate. The indirect resistance spot welding was performed at an appropriate position 50 mm or more inside from the end face of the stainless steel plate. The width of the overlapping part between the stainless steel plates was 30-50 mm. Further, the stainless steel plate and the steel pipe pile were temporarily welded by indirect resistance seam welding at a position near the overlapping portion outside the overlapping portion. The construction conditions for indirect resistance spot welding and indirect resistance seam welding here were the construction conditions INDSP-1 and INDSM-1, respectively.

次いで、前記ステンレス鋼板の重なり部の上板端面と下板表面とがなす段差部（鋼管杭長さ方向に延在）をその全長にわたりＴＩＧ溶接により重ね隅肉溶接し、該段差部の隅に存在していた隙を密封した。さらに、前記重ね継ぎ被覆部の境界においてステンレス鋼板端面と鋼管杭表面とがなす段差部（鋼管杭円周方向に延在）をその全長にわたりＴＩＧ溶接により重ね隅肉溶接し、該段差部の隅に存在していた隙を密封した。ここでのＴＩＧ溶接の施工条件は前記施工条件TIG-1 とした。   Next, the step portion (extending in the length direction of the steel pipe pile) formed by the upper plate end surface and the lower plate surface of the overlapping portion of the stainless steel plate is overlapped and welded by TIG welding over the entire length, and is formed at the corner of the step portion. The gap that existed was sealed. Further, a step portion (extending in the circumferential direction of the steel pipe pile) formed by the end face of the stainless steel plate and the steel pipe pile surface at the boundary of the lap joint covering portion is overlapped by TIG welding over the entire length thereof, and a corner of the step portion is formed. The gap that existed in was sealed. The construction conditions for TIG welding here were the construction conditions TIG-1.

なお、前記鋼材と同一組成・同一厚さの鋼材試片および前記被覆板と同一組成・同一厚さのステンレス鋼板試片とを用いて同様のＴＩＧ溶接により作製した鋼材試片とステンレス鋼板試片の重ね隅肉溶接継手試料、およびステンレス鋼板試片同士の重ね隅肉溶接継手試料の各溶接部について測定したＣＰＴ値はそれぞれ30℃、30℃であった。   A steel specimen and a stainless steel specimen prepared by the same TIG welding using a steel specimen having the same composition and thickness as the steel and a stainless steel specimen having the same composition and thickness as the covering plate. The CPT values measured for the welds of the lap fillet welded joint samples and the lap fillet welded joint samples of the stainless steel plate specimens were 30 ° C. and 30 ° C., respectively.

前記ＴＩＧ溶接完了後、実施例１と同様にして、該両端部の一方に重防食塗装、他方に電気防食措置を施した。   After completion of the TIG welding, in the same manner as in Example 1, a heavy anticorrosion coating was applied to one of the both ends, and an anticorrosion measure was applied to the other.

このような防食仕様を施した鋼管杭を、重防食塗装部が海上部、電気防食措置部が海中部に位置するように海岸中に打ち込み、５年間暴露試験を行なった。結果を表３に示す。溶接ビード部は良好な耐食性を示したものの、ステンレス鋼板母材およびビード部周囲の熱影響部で孔食および海洋生物付着による隙間腐食が発生した。
（比較例４）
鋼材として炭素鋼からなる鋼管表面の黒皮をブラスト処理で取り除いてなる鋼管杭を用いた。覆装板として、板厚0.4mm のオーステナイト系耐海水ステンレス鋼（表１のS1）の帯板コイルから鋼管杭の寸法に合わせた所定長さだけ巻き戻して切断することにより複数枚切出したものを用いた。 Steel pipe piles with such anti-corrosion specifications were driven into the coast so that the heavy anti-corrosion coating part was located on the sea and the electro-corrosion protection part was located on the sea, and an exposure test was conducted for 5 years. The results are shown in Table 3. Although the weld bead portion showed good corrosion resistance, pitting corrosion and crevice corrosion due to adhesion of marine organisms occurred in the heat-affected zone around the stainless steel plate base material and the bead portion.
(Comparative Example 4)
The steel pipe pile which removed the black skin of the steel pipe surface which consists of carbon steel by blasting as steel materials was used. A cover plate made of austenite seawater resistant stainless steel (S1 in Table 1) with a thickness of 0.4mm was cut out by unwinding and cutting a predetermined length according to the dimensions of the steel pipe pile. Was used.

複数の覆装板を順次インダイレクト抵抗スポット溶接により鋼管杭表面に仮止め溶接し、互いの端部を重ね合わせて鋼管杭表面の円周方向に這わせて一周させることにより、鋼管杭の両端部３ｍから内側の領域をステンレス鋼板による重ね継ぎ被覆部となした。前記インダイレクト抵抗スポット溶接は、ステンレス鋼板の端面から50mm以上内側の適宜の位置で行なった。ステンレス鋼板同士の重なり部の幅は30〜50mmとした。   Both ends of the steel pipe pile are welded to the surface of the steel pipe pile by indirect resistance spot welding in sequence, and the ends of each cover plate are overlapped with each other and rolled around in the circumferential direction of the steel pipe pile surface. The inner region from the portion 3m was a lap joint covering portion made of a stainless steel plate. The indirect resistance spot welding was performed at an appropriate position 50 mm or more inside from the end face of the stainless steel plate. The width of the overlapping part between the stainless steel plates was 30-50 mm.

次いで、前記ステンレス鋼板の重なり部の上板と下板とを上板端に可及的に近い位置で鋼管杭長さ方向に沿った全長にわたりインダイレクト抵抗シーム溶接により縫合接合した。さらに、前記重ね継ぎ被覆部の境界においてステンレス鋼板と鋼管杭とをステンレス鋼板端に可及的に近い位置で鋼管杭円周方向に沿った全長にわたりインダイレクト抵抗シーム溶接により縫合接合した。この縫合接合線で囲まれた領域内の鋼材表面は外界から遮断された。ここでのインダイレクト抵抗スポット溶接、インダイレクト抵抗シーム溶接の施工条件はそれぞれ前記施工条件INDSP-1 、INDSM-1 とした。   Next, the upper plate and the lower plate of the overlapped portion of the stainless steel plates were joined by indirect resistance seam welding over the entire length along the steel pipe pile length direction at a position as close as possible to the upper plate end. Further, the stainless steel plate and the steel pipe pile were joined by stitching by indirect resistance seam welding over the entire length along the circumferential direction of the steel pipe pile at a position as close as possible to the end of the stainless steel plate at the boundary of the lap joint covering portion. The surface of the steel material in the region surrounded by the suture joint line was blocked from the outside. The construction conditions for indirect resistance spot welding and indirect resistance seam welding here were the construction conditions INDSP-1 and INDSM-1, respectively.

なお、前記鋼材と同一組成・同一厚さの鋼材試片および前記被覆板と同一組成・同一厚さのステンレス鋼板試片とを用いて同様のインダイレクト抵抗シーム溶接により作製した鋼材試片とステンレス鋼板試片の縫合接合継手試料、およびステンレス鋼板試片同士の縫合接合継手試料の各溶接部について測定したＣＰＴ値はそれぞれ30℃、40℃であった。   In addition, a steel specimen and stainless steel produced by the same indirect resistance seam welding using a steel specimen having the same composition and thickness as the steel and a stainless steel specimen having the same composition and thickness as the covering plate. The CPT values measured for each welded portion of the stitched joint specimen of the steel plate specimen and the stitched joint specimen of the stainless steel specimen were 30 ° C. and 40 ° C., respectively.

前記インダイレクト抵抗シーム溶接完了後、実施例１と同様にして、該両端部の一方に重防食塗装、他方に電気防食措置を施した。   After completion of the indirect resistance seam welding, a heavy anticorrosion coating was applied to one of the both end portions, and an anticorrosion measure was applied to the other, in the same manner as in Example 1.

このような防食仕様を施した鋼管杭を、重防食塗装部が海上部、電気防食措置部が海中部に位置するように海岸中に打ち込み、５年間暴露試験を行なった。結果を表３に示す。   Steel pipe piles with such anti-corrosion specifications were driven into the coast so that the heavy anti-corrosion coating part was located on the sea and the electro-corrosion protection part was located on the sea, and an exposure test was conducted for 5 years. The results are shown in Table 3.

ステンレス鋼板で被覆した部位については、縫合接合部において、インダイレクトシーム溶接時に発生した隙間部から隙間腐食が発生した。また、非縫合接合部においては、ステンレス鋼板母材そのものの耐食性は問題ないものの、位置的に上方に存在する露出した鋼管杭で発生した流れ錆（もらい錆）によって表面が汚染された。一方、鋼管杭本体については、海上部に位置する露出部位で剥離状の錆や錆瘤が発生した。また海中部に位置する露出部位ではステンレス鋼板が軟鋼 (炭素鋼）より貴な腐食電位を示すため、鋼材の腐食が加速される所謂異種金属接触腐食が認められた。   About the site | part coat | covered with the stainless steel plate, crevice corrosion generate | occur | produced from the clearance gap part which generate | occur | produced at the time of indirect seam welding in the stitching joining part. In addition, although the corrosion resistance of the stainless steel plate base material itself was not a problem at the non-sewn joint portion, the surface was contaminated by the flow rust (reception rust) generated in the exposed steel pipe pile existing above. On the other hand, about the steel pipe pile main body, peeling-like rust and rust were generated in the exposed part located in the sea upper part. Moreover, since the stainless steel plate shows a noble corrosion potential over mild steel (carbon steel) at the exposed part located in the sea, so-called dissimilar metal contact corrosion that accelerates corrosion of the steel material was observed.

Figure 0004262018
Figure 0004262018

本発明の一実施形態を示す模式図（ａ：立体図、ｂ：Ａ部断面図、ｃ：Ｂ部断面図）である。It is a schematic diagram (a: solid figure, b: A section sectional view, c: B section sectional view) which shows one embodiment of the present invention. 本発明の一実施形態を示す模式図（ａ：立体図、ｂ：Ａ部断面図、ｃ：Ｂ部断面図）である。It is a schematic diagram (a: solid figure, b: A section sectional view, c: B section sectional view) which shows one embodiment of the present invention. 本発明の一実施形態を示す模式図（ａ：立体図、ｂ：Ａ部断面図、ｃ：Ｂ部断面図）である。It is a schematic diagram (a: solid figure, b: A section sectional view, c: B section sectional view) which shows one embodiment of the present invention. 本発明の一実施形態を示す模式図（ａ：立体図、ｂ：Ａ部断面図、ｃ：Ｂ部断面図）である。It is a schematic diagram (a: solid figure, b: A section sectional view, c: B section sectional view) which shows one embodiment of the present invention. 本発明の一実施形態を示す模式図（ａ：立体図、ｂ：Ａ部断面図、ｃ：Ｂ部断面図）である。It is a schematic diagram (a: solid figure, b: A section sectional view, c: B section sectional view) which shows one embodiment of the present invention. 本発明の一実施形態を示す模式図（ａ：立体図、ｂ：Ａ部断面図、ｃ：Ｂ部断面図）である。It is a schematic diagram (a: solid figure, b: A section sectional view, c: B section sectional view) which shows one embodiment of the present invention. 本発明の一実施形態を示す模式図（ａ：立体図、ｂ：Ａ部断面図、ｃ：Ｂ部断面図）である。It is a schematic diagram (a: solid figure, b: A section sectional view, c: B section sectional view) which shows one embodiment of the present invention. 本発明の一実施形態を示す模式図（ａ：立体図、ｂ：Ａ部断面図、ｃ：Ｂ部断面図）である。It is a schematic diagram (a: solid figure, b: A section sectional view, c: B section sectional view) which shows one embodiment of the present invention. 本発明の一実施形態を示す模式図（ａ：立体図、ｂ：Ａ部断面図、ｃ：Ｂ部断面図）である。It is a schematic diagram (a: solid figure, b: A section sectional view, c: B section sectional view) which shows one embodiment of the present invention.

符号の説明Explanation of symbols

１ 鋼材（鋼管、鋼管杭等）
２ 覆装板（オーステナイト系耐海水ステンレス鋼板）
２ａ 覆装板端部同士の重なり部
３ 第１の溶接部
４ 第２の溶接部
５ 第３の溶接部
６ 第１の溶接部（抵抗スポット溶接）
７ 第４の溶接部
８ 第１の溶接部（抵抗シーム溶接） 1 Steel materials (steel pipes, steel pipe piles, etc.)
2 Covering plate (Austenitic seawater resistant stainless steel plate)
2a Overlapping portion of covering plate end portions 3 First welded portion 4 Second welded portion 5 Third welded portion 6 First welded portion (resistance spot welding)
7 Fourth welded portion 8 First welded portion (resistance seam welding)

Claims (6)

鋼材の表面の少なくとも一部を一枚又は複数枚の覆装板で被覆してなる構造物構築部材であって、前記覆装板は下記のＰＲＥが43以上になる板厚0.2 〜5.0mm のオーステナイト系耐海水ステンレス鋼からなり、前記覆装板を前記鋼材表面に仮止めしてなる第１の溶接部と、前記覆装板の端部同士の重なり部の隙を下記のＰＲＥが50以上の溶接棒を用いたＴＩＧ溶接により密封してなる第２の溶接部と、前記覆装板の被覆境界部と前記鋼材表面との隙を下記のＰＲＥが50以上の溶接棒を用いたＴＩＧ溶接により密封してなる第３の溶接部とを有し、かつ前記第２および第３の溶接部が前記オーステナイト系耐海水ステンレス鋼と同等以上の耐食性を有することを特徴とする構造物構築部材。
記
ＰＲＥ＝Cr＋3.3 ×Mo＋20×Ｎ。ただしＷ含有の場合は、ＰＲＥ＝Cr＋3.3 ×（Mo＋0.5 ×Ｗ）＋20×Ｎとする。ここに右辺の元素記号はその元素の濃度（mass% ）を表す。 A structure construction member formed by covering at least a part of the surface of a steel material with one or a plurality of covering plates, the covering plate having a plate thickness of 0.2 to 5.0 mm so that the following PRE is 43 or more The following PRE is 50 or more in the gap between the first welded portion made of austenitic seawater-resistant stainless steel and temporarily fastening the covering plate to the steel surface and the end portion of the covering plate. TIG welding using a welding rod in which the following PRE is 50 or more between the second welded portion sealed by TIG welding using a welding rod and the gap between the covering boundary portion of the covering plate and the steel surface And a third welded portion that is hermetically sealed, and the second and third welded portions have corrosion resistance equal to or higher than that of the austenitic seawater resistant stainless steel.
Record
PRE = Cr + 3.3 × Mo + 20 × N. However, in the case of containing W, PRE = Cr + 3.3 × (Mo + 0.5 × W) + 20 × N. Here, the element symbol on the right side represents the concentration (mass%) of the element. 鋼材の表面の少なくとも一部を一枚又は複数枚の覆装板で被覆してなる構造物構築部材であって、前記覆装板は下記のＰＲＥが43以上になる板厚0.2 〜5.0mm のオーステナイト系耐海水ステンレス鋼からなり、前記覆装板を前記鋼材表面に仮止めしてなる第１の溶接部と、前記覆装板の端部同士の重なり部を固定してなる第４の溶接部と、前記覆装板の端部同士の重なり部の隙を下記のＰＲＥが50以上の溶接棒を用いたＴＩＧ溶接により密封してなる第２の溶接部と、前記覆装板の被覆境界部と前記鋼材表面との隙を下記のＰＲＥが50以上の溶接棒を用いたＴＩＧ溶接により密封してなる第３の溶接部とを有し、かつ前記第２、第３の溶接部が前記オーステナイト系耐海水ステンレス鋼と同等以上の耐食性を有することを特徴とする構造物構築部材。
記
ＰＲＥ＝Cr＋3.3 ×Mo＋20×Ｎ。ただしＷ含有の場合は、ＰＲＥ＝Cr＋3.3 ×（Mo＋0.5 ×Ｗ）＋20×Ｎとする。ここに右辺の元素記号はその元素の濃度（mass% ）を表す。 A structure construction member formed by covering at least a part of the surface of a steel material with one or a plurality of covering plates, the covering plate having a plate thickness of 0.2 to 5.0 mm so that the following PRE is 43 or more 4th welding which consists of austenitic seawater-resistant stainless steel, and fixes the overlap part of the 1st welding part which temporarily fixes the said covering board to the said steel material surface, and the edge parts of the said covering board And a second welded portion in which the gap between the end portions of the covering plate is sealed by TIG welding using a welding rod having a PRE of 50 or more, and the covering boundary of the covering plate And a third welded portion in which the following PRE is sealed by TIG welding using a welding rod having a PRE of 50 or more , and the second and third welded portions are Structure construction member characterized by having corrosion resistance equivalent to or better than austenitic seawater resistant stainless steel .
Record
PRE = Cr + 3.3 × Mo + 20 × N. However, in the case of containing W, PRE = Cr + 3.3 × (Mo + 0.5 × W) + 20 × N. Here, the element symbol on the right side represents the concentration (mass%) of the element. 前記構造物構築部材に、重防食塗料が塗装され、および／または前記構造物構築部材の鋼材に、電気防食用電極が装着されていることを特徴とする請求項１または２に記載の構造物構築部材。 The structure according to claim 1 or 2 , wherein a heavy-duty anticorrosive paint is applied to the structure building member, and / or an electrode for cathodic protection is attached to a steel material of the structure building member. Construction member. 鋼材の表面に、下記のＰＲＥが43以上になるオーステナイト系耐海水ステンレス鋼からなる板厚0.2 〜5.0mm の複数枚の覆装板をその隣り合う端部同士が重なるように配置し、前記覆装板を前記鋼材表面に抵抗溶接で仮止め後、前記覆装板の端部同士の重なり部の隙、および前記覆装板の被覆境界部と前記鋼材表面との隙を、溶接電流50Ａ以上160 Ａ未満、溶接速度80mm/min以上600mm/min 未満の条件下で下記のＰＲＥが50以上の溶接棒を使用するＴＩＧ溶接により、密封することを特徴とする構造物構築部材の製造方法。
記
ＰＲＥ＝Cr＋3.3 ×Mo＋20×Ｎ。ただしＷ含有の場合は、ＰＲＥ＝Cr＋3.3 ×（Mo＋0.5 ×Ｗ）＋20×Ｎとする。ここに右辺の元素記号はその元素の濃度（mass% ）を表す。 On the surface of the steel material, a plurality of covering plates having a thickness of 0.2 to 5.0 mm made of austenitic seawater-resistant stainless steel having the following PRE of 43 or more are arranged so that their adjacent ends overlap each other. After temporarily fixing the covering plate to the steel surface by resistance welding, the gap between the end portions of the covering plate and the gap between the covering boundary portion of the covering plate and the steel surface is set to a welding current of 50 A or more. A method for producing a structure building member, wherein sealing is performed by TIG welding using a welding rod having a PRE of 50 or more under the conditions of less than 160 A and a welding speed of 80 mm / min or more and less than 600 mm / min.
PRE = Cr + 3.3 × Mo + 20 × N. However, in the case of containing W, PRE = Cr + 3.3 × (Mo + 0.5 × W) + 20 × N. Here, the element symbol on the right side represents the concentration (mass%) of the element. 鋼材の表面に、下記のＰＲＥが43以上になるオーステナイト系耐海水ステンレス鋼からなる板厚0.2 〜5.0mm の複数枚の覆装板をその隣り合う端部同士が重なるように配置し、前記覆装板を前記鋼材表面に抵抗溶接で仮止め後、前記覆装板の重なり部を抵抗スポット溶接で固定し、さらに前記覆装板の端部同士の重なり部の隙、および前記覆装板の被覆境界部と前記鋼材表面との隙を、溶接電流50Ａ以上160 Ａ未満、溶接速度80mm/min以上600mm/min 未満の条件下で下記のＰＲＥが50以上の溶接棒を使用するＴＩＧ溶接により、密封することを特徴とする構造物構築部材の製造方法。
記
ＰＲＥ＝Cr＋3.3 ×Mo＋20×Ｎ。ただしＷ含有の場合は、ＰＲＥ＝Cr＋3.3 ×（Mo＋0.5 ×Ｗ）＋20×Ｎとする。ここに右辺の元素記号はその元素の濃度（mass% ）を表す。 On the surface of the steel material, a plurality of covering plates having a thickness of 0.2 to 5.0 mm made of austenitic seawater-resistant stainless steel having the following PRE of 43 or more are arranged so that their adjacent ends overlap each other. After temporarily fixing the covering plate to the steel surface by resistance welding, the overlapping portion of the covering plate is fixed by resistance spot welding, and further, the gap between the overlapping portions of the covering plate, and the covering plate TIG welding using a welding rod having a PRE of 50 or more under the conditions of a welding current of 50 A or more and less than 160 A and a welding speed of 80 mm / min or more and less than 600 mm / min, with the gap between the coating boundary and the steel material surface, A method for producing a structure building member, characterized by sealing.
PRE = Cr + 3.3 × Mo + 20 × N. However, in the case of containing W, PRE = Cr + 3.3 × (Mo + 0.5 × W) + 20 × N. Here, the element symbol on the right side represents the concentration (mass%) of the element. 前記ＴＩＧ溶接による隙の密封後、前記構造物構築部材に、重防食塗料を塗装し、および／または前記構造物構築部材の鋼材に、電気防食用電極を装着することを特徴とする請求項４または５に記載の構造物構築部材の製造方法。 After sealing the gap by the TIG welding, the structure building member, coating a heavy duty coating, and / or the steel of the structure building member, according to claim 4, characterized in that attaching the sacrificial electrode Or the manufacturing method of the structure construction member of 5 .
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