JP2018079503A - Method for manufacturing spot weldment and spot welding electrode - Google Patents
Method for manufacturing spot weldment and spot welding electrode Download PDFInfo
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本発明は、スポット溶接に関する。より詳細には、本発明は、重ね合わせた鋼板などの被溶接板を電気抵抗発熱で溶融させて接合するスポット溶接によって溶接物を製造する方法に関すると共に、かかる溶接のためのスポット溶接電極にも関する。 The present invention relates to spot welding. More specifically, the present invention relates to a method of manufacturing a welded product by spot welding in which welded plates such as stacked steel plates are melted and joined by electric resistance heat generation, and also to a spot welding electrode for such welding. Related.
従前より、鋼板同士の接合には溶接が多く用いられている。例えば自動車の車体は、鋼板同士を溶接することで一般に構成されている。溶接の種類としてスポット溶接があり、自動車１台でみた場合では鋼板の接合箇所の多くがスポット溶接で接合されている。 Conventionally, welding is often used for joining steel plates. For example, the body of an automobile is generally configured by welding steel plates together. There is spot welding as a type of welding, and when viewed with one automobile, many of the joining points of the steel plates are joined by spot welding.
スポット溶接では、重ね合わせた鋼板に対して電極間で局所的に通電して抵抗熱を発生させる。抵抗発熱により鋼板が溶融するので、最終的には溶融に起因して鋼板同士の接合がなされる。より具体的には、スポット溶接は、対を成す電極を備えた溶接ガンを一般的に用いる。かかる対を成す電極で重ね合わせた鋼板を挟み込み圧力を加えながら電極間に電流を流す。これにより鋼板に抵抗発熱が生じ、鋼板が局所的に溶融するので、その部分が最終的に冷却固化して点状の溶接部が形成される。 In spot welding, resistance heat is generated by locally energizing the stacked steel plates between the electrodes. Since the steel plates are melted by the resistance heat generation, the steel plates are finally joined due to the melting. More specifically, spot welding typically uses a welding gun with a pair of electrodes. Current is passed between the electrodes while sandwiching the steel plates overlapped by the pair of electrodes and applying pressure. As a result, resistance heat is generated in the steel sheet, and the steel sheet is locally melted, so that the portion is finally cooled and solidified to form a dotted weld.
スポット溶接で形成される点状の溶接部は“ナゲット”と一般に称される。ナゲットは、抵抗発熱に起因した鋼板の溶融部分が冷却固化した部分に相当し、このナゲットの存在によって鋼板同士が接合され、所望のスポット溶接物が得られることになる。 A spot weld formed by spot welding is generally referred to as a “nugget”. The nugget corresponds to a portion where the molten portion of the steel plate caused by resistance heat generation is cooled and solidified, and the steel plates are joined together by the presence of the nugget, and a desired spot weld is obtained.
本願発明者らは、スポット溶接に起因する応力の問題点に気付き、そのための対策を取る必要性を見出した。 The inventors of the present application have noticed the problem of stress caused by spot welding, and have found that it is necessary to take countermeasures therefor.
具体的には以下の問題があることを本願発明者は見出した。スポット溶接では、上述した如く溶接に供する重ね合わせた鋼板（以下では「被溶接積層体」とも称す）を電極で挟持した状態で被溶接積層体を加圧しながら通電させるが、かかるスポット溶接に起因して被溶接積層体に不都合な応力がもたらされる虞がある。特に、スポット溶接に起因して、被溶接積層体にもたされる不都合な応力の分布（例えば「最大引張応力以上となる引張応力の分布」）が鋼板母材とナゲットとの界面に位置付けられることがある。このような界面における応力は、溶接物にとって望ましくなく、遅れ破壊および／または疲労破壊などの誘因となり得る。そのような場合には、例えば特許文献１のように溶接工程・溶接条件を工夫することで対応可能であるものの、今度は生産性が低下する等の新たな問題が発生する虞がある。 Specifically, the present inventors have found that there are the following problems. In spot welding, as described above, the laminated steel sheets (hereinafter also referred to as “welded laminates”) to be welded are energized while pressing the laminate to be welded while being sandwiched between electrodes. As a result, an undesirable stress may be caused to the welded laminate. In particular, an unfavorable stress distribution (for example, “a tensile stress distribution exceeding the maximum tensile stress”) applied to the welded laminate due to spot welding is positioned at the interface between the steel plate base material and the nugget. Sometimes. Such stresses at the interface are undesirable for the weldment and can lead to delayed fracture and / or fatigue failure. In such a case, it can be dealt with by devising the welding process and welding conditions as in Patent Document 1, for example, but there is a possibility that a new problem such as a decrease in productivity may occur.
本発明はかかる事情に鑑みて為されたものである。即ち、本発明の主たる目的は、溶接物にもたらされる応力に鑑みた好適なスポット溶接技術を提供することである。 The present invention has been made in view of such circumstances. That is, the main object of the present invention is to provide a suitable spot welding technique in view of the stress caused to the welded article.
本願発明者は、従来技術の延長線上で対応するのではなく、新たな方向で対処することによって上記問題点の解決を試みた。その結果、上記主たる目的が達成されたスポット溶接物の製造方法の発明に至ると共に、それを実施するためのスポット溶接電極の発明にも至った。 The inventor of the present application tried to solve the above-mentioned problem by dealing with a new direction instead of dealing with the extension of the prior art. As a result, the present invention has led to an invention of a method for manufacturing a spot welded article in which the above-mentioned main object has been achieved, and an invention of a spot weld electrode for carrying out the invention.
本発明の製造方法の発明は、スポット溶接物を製造する方法に関し、
少なくとも２枚の鋼板を重ね合わせて得られる被溶接積層体を一対の電極で加圧しながら通電を行うスポット溶接において、電極と被溶接積層体との接触面は、互いに直交する方向の一方の寸法が他方の寸法より小さい非均一形状を有することを特徴とする。
The invention of the manufacturing method of the present invention relates to a method of manufacturing a spot welded article,
In spot welding in which energization is performed while pressing a welded laminate obtained by superposing at least two steel plates with a pair of electrodes, the contact surface between the electrode and the welded laminate is one dimension in a direction perpendicular to each other. Has a non-uniform shape smaller than the other dimension.
また、本発明の溶接電極は、スポット溶接に用いる電極に関している。かかる本発明のスポット溶接電極は、互いに直交する方向の一方の寸法が他方の寸法よりも小さい非均一形状面が電極先端部に含まれていることを特徴とする。 The welding electrode of the present invention relates to an electrode used for spot welding. The spot welding electrode of the present invention is characterized in that the electrode tip portion includes a non-uniformly shaped surface in which one dimension in a direction perpendicular to each other is smaller than the other dimension.
本発明では、被溶接積層体に生じ得る応力を好適に偏移させることができる。具体的には、被溶接積層体にもたらされる不都合な応力の分布（例えば「最大引張応力以上となる引張応力の分布」）を鋼板母材とナゲットとの界面よりも内側に位置付けることができる。これは、不都合となり得る応力を鋼板母材とナゲットとの界面を避けるように制御できることを意味している。このように本発明では不都合な応力の分布領域を鋼板母材とナゲットとの界面から外すことができるので、遅れ破壊および／または疲労破壊などの誘因が減じられた所望の溶接物を得ることができる。なお、本発明は、電極と被溶接積層体との接触面を“非均一形状”の特異な面にすることに存するので、スポット溶接の生産性自体の低下を引き起こす虞はない。 In the present invention, the stress that can occur in the welded laminate can be suitably shifted. Specifically, an unfavorable stress distribution (for example, “a distribution of a tensile stress equal to or greater than the maximum tensile stress”) caused to the welded laminate can be positioned inside the interface between the steel plate base material and the nugget. This means that stress that can be inconvenient can be controlled so as to avoid the interface between the steel plate base material and the nugget. Thus, in the present invention, an undesired stress distribution region can be removed from the interface between the steel plate base material and the nugget, so that it is possible to obtain a desired weld with reduced incentives such as delayed fracture and / or fatigue fracture. it can. Note that the present invention resides in that the contact surface between the electrode and the laminate to be welded is a unique surface of “non-uniform shape”, so there is no possibility of causing a decrease in the productivity of spot welding itself.
以下では、図面を参照して本発明の一実施形態に係る「スポット溶接物の製造方法」および「スポット溶接電極」をより詳細に説明する。図面における各種の要素は、本発明の理解のために模式的かつ例示的に示したにすぎず、外観や寸法比などは実物と異なり得る。 Hereinafter, a “spot welded product manufacturing method” and a “spot weld electrode” according to an embodiment of the present invention will be described in more detail with reference to the drawings. Various elements in the drawings are merely schematically and exemplarily shown for understanding of the present invention, and the appearance, dimensional ratio, and the like may be different from the actual ones.
本明細書において「スポット溶接物」といった用語は、いわゆるスポット溶接（抵抗スポット溶接）によって得られる溶接物、即ち、電気抵抗による発熱（ジュール熱）を利用して互いに溶接された鋼板を指している。したがって、本発明において「スポット溶接物」は、広義には、溶接ガンを用いてスポット溶接された少なくとも２枚の鋼板のことを意味しており、狭義には、「互いに直交する方向の一方の寸法が他方の寸法よりも小さい非均一形状面が電極先端部に含まれるスポット溶接電極」によってスポット溶接された鋼板のことを意味している。 In this specification, the term “spot weld” refers to a weld obtained by so-called spot welding (resistance spot welding), that is, steel plates welded to each other using heat generated by electrical resistance (Joule heat). . Therefore, in the present invention, the “spot welded product” means, in a broad sense, at least two steel plates spot-welded using a welding gun, and in a narrow sense, “one of the directions orthogonal to each other”. It means a steel plate spot welded by a “spot welding electrode in which a non-uniformly shaped surface having a smaller dimension than the other dimension is included in the electrode tip”.
本明細書で直接的または間接的に説明される“上下”の方向は、製造時にスポット溶接される鋼板の重ね合せに基づいており、鋼板同士が重ね合わされる方向（すなわち、重ね合せで得られる被溶接積層体の積層方向）が上下方向に相当する。本発明に係る典型的な態様として鋼板同士が全体に水平状態で重ね合わされる場合を例にとると「鉛直下向き」が「下方向」に相当し、その反対側が「上方向」に相当する。 The “up and down” directions described directly or indirectly herein are based on the superposition of steel plates that are spot welded during manufacture, and are obtained by the superposition of steel plates (ie, by superposition). The lamination direction of the laminate to be welded) corresponds to the vertical direction. Taking a case where steel plates are overlapped as a whole as a typical embodiment according to the present invention, “vertically downward” corresponds to “downward” and the opposite side corresponds to “upward”.
［本発明の製造方法］
本発明に係る製造方法は、スポット溶接物を製造するための方法である。具体的には、本発明の製造方法は、少なくとも２枚の鋼板を重ね合わせて得られる被溶接積層体を一対の電極で加圧しながら通電を行うスポット溶接において、電極と被溶接積層体との接触面が「互いに直交する方向の一方の寸法が他方の寸法より小さい非均一形状」となるように電極と被溶接積層体とを互いに接触させる。
[Production method of the present invention]
The manufacturing method according to the present invention is a method for manufacturing a spot welded product. Specifically, in the manufacturing method of the present invention, in spot welding in which energization is performed while pressing a welded laminate obtained by superposing at least two steel plates with a pair of electrodes, the electrode and the welded laminate are The electrode and the laminate to be welded are brought into contact with each other so that the contact surface has a “non-uniform shape in which one dimension in a direction perpendicular to each other is smaller than the other dimension”.
本発明の製造方法では、いわゆる溶接ガン電極を鋼板に対して接触させた状態でスポット溶接を行うところ、かかる電極と被溶接積層体との接触面が“非均一形状”（互いに直交する方向の一方の寸法が他方の寸法より小さい非均一形状）となっている。つまり、“電極と鋼板との接触面”という観点でスポット溶接を捉えた場合、そのスポット溶接の接触面が「互いに直交する方向の一方の寸法が他方の寸法より小さい非均一形状」となるように電極が被溶接積層体に対して接触する。このような特徴に起因して、被溶接積層体に生じる応力が好適に制御される。より具体的には、被溶接積層体に生じる不都合な応力の分布を好適に偏移させることができ、鋼板母材とナゲットとの界面を避けるように「鋼板の最大引張応力以上となる引張応力」の発生位置・分布領域を制御できる。 In the manufacturing method of the present invention, spot welding is performed in a state where a so-called welding gun electrode is in contact with a steel plate, and the contact surface between the electrode and the laminate to be welded has a “non-uniform shape” (in a direction orthogonal to each other). One dimension is smaller than the other dimension). In other words, when spot welding is considered from the viewpoint of “contact surface between electrode and steel plate”, the contact surface of the spot welding becomes “a non-uniform shape in which one dimension in a direction perpendicular to each other is smaller than the other dimension”. The electrode contacts the welded laminate. Due to such characteristics, the stress generated in the welded laminate is suitably controlled. More specifically, the distribution of the unfavorable stress generated in the laminate to be welded can be suitably shifted, and so as to avoid the interface between the steel plate base material and the nugget, the “tensile stress exceeding the maximum tensile stress of the steel plate” Can be controlled.
被溶接積層体において鋼板母材とナゲットとの界面に「鋼板の最大引張応力以上となる引張応力」が存在すると、遅れ破壊および／または疲労破壊などの誘因となり得る。つまり、そのような過度な応力がもたらされる被溶接積層体の領域に「鋼板母材とナゲットとの界面」が含まれると、静的・動的疲労破壊を誘発する要因となり得る。この点、本発明では鋼板母材とナゲットとの界面から外れるように過度な応力を位置付けることができる。本発明では「鋼板の最大引張応力以上となる引張応力」が鋼板母材とナゲットとの界面に存在せず、かかる界面よりも内側にかかる不都合な応力の分布を偏移させることができる。よって、本発明に従って得られた溶接物は、静的・動的疲労破壊を誘発する要因が減じられ、長期疲労強さなどの点でより優れた溶接鋼板となる。 In the welded laminate, the presence of “tensile stress greater than or equal to the maximum tensile stress of the steel sheet” at the interface between the steel sheet base metal and the nugget can cause delayed fracture and / or fatigue fracture. That is, if the “interface between the steel plate base metal and the nugget” is included in the region of the laminate to be welded that causes such excessive stress, it can be a factor inducing static / dynamic fatigue failure. In this regard, in the present invention, excessive stress can be positioned so as to deviate from the interface between the steel plate base material and the nugget. In the present invention, “tensile stress equal to or greater than the maximum tensile stress of the steel plate” does not exist at the interface between the steel plate base material and the nugget, and the distribution of inconvenient stress applied to the inside of the interface can be shifted. Therefore, the welded material obtained according to the present invention is reduced in the factors that induce static and dynamic fatigue failure, and becomes a welded steel plate that is more excellent in terms of long-term fatigue strength.
本発明の製造方法は、スポット溶接時の電極と被溶接積層体との接触面に特徴を有しており、特にその接触面の平面視形状１０に特徴を有している（図１参照）。具体的には、図示するように接触面の平面視形状１０は「互いに直交する方向の一方の寸法ａが他方の寸法ｂより小さい非均一形状」となっている。つまり、電極２０が被溶接積層体５０（鋼板３０の重ね合せで得られる積層体５０）に接触させて行うスポット溶接において電極２０と被溶接積層体５０との接触面の形状１０は、互いに直交する寸法ａおよび寸法ｂが“非均一形状の接触面”を形成すべく寸法差を有している。 The manufacturing method of the present invention is characterized by the contact surface between the electrode and the laminate to be welded during spot welding, and particularly has a feature in a plan view shape 10 of the contact surface (see FIG. 1). . Specifically, as shown in the figure, the planar shape 10 of the contact surface is “a non-uniform shape in which one dimension a in a direction perpendicular to each other is smaller than the other dimension b”. That is, in spot welding performed by bringing the electrode 20 into contact with the welded laminate 50 (laminate 50 obtained by superimposing the steel plates 30), the shape 10 of the contact surface between the electrode 20 and the welded laminate 50 is orthogonal to each other. Dimension a and dimension b have a dimensional difference so as to form a “non-uniform contact surface”.
本明細書にいう「電極と被溶接積層体との接触面」とは、広義には、少なくとも２枚の鋼板の重ね合わせで構成される被溶接積層体と、スポット溶接に用いる電極とを互いに接触させた際にもたらされる接触面を意味しており、狭義には、図１に示す如くスポット溶接時にて被溶接積層体５０の外側主面と溶接ガンの電極２０とが成す接触部分の平面視形状１０（被溶接積層体の積層方向に沿って上側または下側からみた接触部分の透視平面形状）を意味している。 The term “contact surface between an electrode and a laminate to be welded” in the present specification means, in a broad sense, a laminate to be welded constituted by superposition of at least two steel plates and an electrode used for spot welding. This means a contact surface that is brought into contact with each other. In a narrow sense, as shown in FIG. 1, the plane of the contact portion formed by the outer main surface of the welded laminate 50 and the electrode 20 of the welding gun during spot welding is shown. The visual shape 10 (the transparent planar shape of the contact portion viewed from the upper side or the lower side along the stacking direction of the welded laminate) is meant.
また、本明細書にいう「互いに直交する方向の一方の寸法が他方の寸法より小さい非均一形状を有する」とは、広義には、平面形状の直交寸法が互いに異なることを意味しており、狭義には、電極と被溶接積層体との接触面の平面形状について、図１に示す如く互いに直交する方向の一方の寸法ａと他方の寸法ｂとを比べた場合、一方の寸法ａが他方の寸法ｂよりも小さくなり、それによって、スポット溶接時における電極２０と被溶接積層体５０との接触部の平面視形状１０が異方形となることを意味している。 In addition, the phrase “having a non-uniform shape in which one dimension in a direction perpendicular to each other is smaller than the other dimension” in the present specification means that the orthogonal dimensions of the planar shape are different from each other in a broad sense. In a narrow sense, when one dimension a in the direction orthogonal to each other and the other dimension b are compared as shown in FIG. 1 with respect to the planar shape of the contact surface between the electrode and the laminate to be welded, one dimension a is the other. This means that the shape 10 in plan view of the contact portion between the electrode 20 and the welded laminate 50 during spot welding becomes anisotropic.
「一方の寸法ａが他方の寸法ｂよりも小さい非均一形状」としては、種々の形状が考えられ、例えば図１の下側に示すように楕円形、矩形または菱形（もしくは斜方形）であってよい。“楕円形”は図１の最下左に示すように互いに直交する短径長さａ１と長径長さｂ１とから成る非均一形状である。“矩形”は図１の最下中央に示すように互いに直交する短軸長さａ２と長軸長さｂ２とから成る非均一形状である。そして、“菱形”／“斜方形”は図１の最下右に示すように互いに直交する短軸長さａ３と長軸長さｂ３とから成る４辺が等しい四角形の非均一形状である。本発明では、このような形状が電極と被溶接積層体との接触面の非均一形状として得られると、スポット溶接に際して被溶接積層体に生じる応力を好適に制御できる。つまり、被溶接積層体に生じる応力の分布を好適に偏移させることができ、鋼板母材とナゲットとの界面を避けるように不都合な応力（鋼板の最大引張応力以上となる引張応力）の発生位置・分布領域を制御できる。 As the “non-uniform shape in which one dimension a is smaller than the other dimension b”, various shapes are conceivable, for example, an ellipse, a rectangle, or a rhombus (or rhombus) as shown in the lower side of FIG. It's okay. The “elliptical shape” is a non-uniform shape composed of a minor axis length a 1 and a major axis length b 1 which are orthogonal to each other, as shown at the bottom left in FIG. The “rectangular shape” is a non-uniform shape composed of a short axis length a 2 and a long axis length b 2 orthogonal to each other as shown in the lowermost center of FIG. The “rhombus” / “rhombic” is a non-uniform shape of a quadrangle having the same four sides consisting of the short axis length a 3 and the long axis length b 3 orthogonal to each other, as shown at the bottom right in FIG. is there. In the present invention, when such a shape is obtained as a non-uniform shape of the contact surface between the electrode and the welded laminate, the stress generated in the welded laminate during spot welding can be suitably controlled. In other words, the stress distribution generated in the welded laminate can be appropriately shifted, and inadvertent stress (tensile stress exceeding the maximum tensile stress of the steel plate) is generated to avoid the interface between the steel plate base material and the nugget. The position / distribution area can be controlled.
ある好適な態様では、一方の寸法が他方の寸法の５０％以上８３％以下となっている。つまり、図２に示すように、電極と被溶接積層体との接触面につき、一方の寸法が他方の寸法の５０％以上８３％以下となっている。より具体的にいえば、接触部分の平面視形状１０において互いに直交する一方の寸法ａと他方の寸法ｂとを比べた場合、一方の寸法ａが他方の寸法ｂの５０％以上８３％以下となることで相対的に短くなっている。 In a preferable aspect, one dimension is 50% or more and 83% or less of the other dimension. That is, as shown in FIG. 2, one dimension is 50% or more and 83% or less of the other dimension about the contact surface of an electrode and a to-be-welded laminated body. More specifically, when comparing one dimension a orthogonal to the other dimension b in the plan view shape 10 of the contact portion, one dimension a is 50% or more and 83% or less of the other dimension b. It becomes relatively short by becoming.
図示する態様でいえば、電極と被溶接積層体との接触面の楕円形につき、好ましくは短径長さａ１が長径長さｂ１の５０％以上８３％以下となっている。つまり、電極と被溶接積層体との接触面が０．５ｂ≦ａ≦０．８３ｂの直交寸法比を有する平面視楕円形となるようにスポット溶接を行うことが好ましい。 Speaking in a manner to be shown, per elliptical contact surface between the electrode and the object to be welded laminate, preferably short necked length a 1 is less than or equal to 83% to 50% or more of major axis length b 1. That is, it is preferable to perform spot welding so that the contact surface between the electrode and the laminate to be welded has an elliptical shape in plan view having an orthogonal dimension ratio of 0.5b ≦ a ≦ 0.83b.
このように「一方の寸法が他方の寸法の５０％以上８３％以下」となる直交寸法比の条件では、スポット溶接に際して被溶接積層体に生じる応力がより好適に制御される。つまり、被溶接積層体に生じる応力の分布を好適に偏移させることができ、鋼板母材とナゲットとの界面を避けるように発生位置・分布領域が制御された応力（鋼板の最大引張応力以上となる引張応力）が被溶接積層体にもたらされる。 In this way, under the condition of the orthogonal dimension ratio in which “one dimension is 50% or more and 83% or less of the other dimension”, the stress generated in the welded laminate during spot welding is more suitably controlled. In other words, the stress distribution generated in the laminate to be welded can be suitably shifted, and the stress at which the generation position / distribution region is controlled to avoid the interface between the steel plate base material and the nugget (greater than the maximum tensile stress of the steel plate) (Tension stress) is brought to the welded laminate.
別のある好適な態様では、他方の寸法が６ｍｍ以上８ｍｍ以下となっている。つまり、図３に示すように、電極と被溶接積層体との接触面につき、相対的に長い寸法である“他方の寸法”が６ｍｍ以上８ｍｍ以下となっている。より具体的にいえば、接触部分の平面視形状１０において互いに直交する寸法のうちでより長い寸法が６ｍｍ以上８ｍｍ以下となっている。一方の寸法ａが他方の寸法ｂの５０％以上８３％以下となっている態様を兼ねる場合、“他方の寸法ｂ”が６ｍｍ以上８ｍｍ以下となり、“一方の寸法ａ”は３ｍｍ以上６．６４ｍｍ以下となる。 In another preferable aspect, the other dimension is 6 mm or more and 8 mm or less. That is, as shown in FIG. 3, the “other dimension”, which is a relatively long dimension, is 6 mm or more and 8 mm or less on the contact surface between the electrode and the laminate to be welded. More specifically, the longer dimension among the dimensions orthogonal to each other in the plan view shape 10 of the contact portion is 6 mm or more and 8 mm or less. When one dimension a is also 50% or more and 83% or less of the other dimension b, “the other dimension b” is 6 mm or more and 8 mm or less, and “one dimension a” is 3 mm or more and 6.64 mm. It becomes as follows.
図示する態様でいえば、電極と被溶接積層体との接触面の楕円形につき、長径長さｂ１が好ましくは６ｍｍ以上８ｍｍ以下となっている。つまり、電極と被溶接積層体との接触面につき６ｍｍ以上８ｍｍ以下の長径条件を有する平面視楕円形となるようにスポット溶接を行うことが好ましい。 Speaking in a manner to be shown, per elliptical contact surface between the electrode and the object to be welded laminate, the major axis length b 1 is preferably has a 6mm or 8mm or less. That is, it is preferable to perform spot welding so that the contact surface between the electrode and the laminate to be welded has an elliptical shape in plan view having a major axis condition of 6 mm or more and 8 mm or less.
このように「他方の寸法が６ｍｍ以上８ｍｍ以下」となる直交寸法の条件では、スポット溶接に際して被溶接積層体に生じる応力がより好適に制御される。つまり、被溶接積層体に生じる応力の分布を好適に偏移させることができ、鋼板母材とナゲットとの界面を避けるように発生位置・分布領域が制御された応力（鋼板の最大引張応力以上となる引張応力）が被溶接積層体にもたらされる。 In this way, under the condition of the orthogonal dimension in which “the other dimension is 6 mm or more and 8 mm or less”, the stress generated in the welded laminate during spot welding is more suitably controlled. In other words, the stress distribution generated in the laminate to be welded can be suitably shifted, and the stress at which the generation position / distribution region is controlled to avoid the interface between the steel plate base material and the nugget (greater than the maximum tensile stress of the steel plate) (Tension stress) is brought to the welded laminate.
ここで、本発明に関連する“非均一形状”に起因する被溶接積層体の応力制御を詳述しておく。本発明では、電極と被溶接積層体との接触面について互いに直交する方向の一方の寸法が他方の寸法より小さい非均一形状となっており、それによって、被溶接積層体に生じる応力が好適に制御され得る。特に、引張応力などの応力に関して「鋼板の最大引張応力以上となる応力の分布」が鋼板母材とナゲットとの界面には存在せず、かかる界面よりも内側に偏移するように制御され得る。これは図４（Ａ）と図４（Ｂ）とを比べると良く理解できる。図４（Ａ）は、電極と被溶接積層体との接触面が“非均一形状”となるスポット溶接の場合の「界面」と「最大引張応力以上となる引張応力の領域」との相対的な位置関係を平面透過図で示している。一方、図４（Ｂ）は、電極と被溶接積層体との接触面が“非均一形状”となっていないスポット溶接（特に従来技術の如く接触面が“円形”となるスポット溶接）の場合の「界面」と「最大引張応力以上となる引張応力の領域」との相対的な位置関係を平面透過図で示している。双方とも、図５に示す如くのスポット溶接に基づいている。つまり、図４（Ａ）および図４（Ｂ）に示す「界面」と「最大引張応力以上となる引張応力の領域」との相対的な位置関係は、鋼板合せ間隙５７が存在する被溶接積層体５０をスポット溶接電極２０で加圧しながらスポット溶接する態様に基づいている。 Here, the stress control of the welded laminate due to the “non-uniform shape” related to the present invention will be described in detail. In the present invention, one dimension in the direction orthogonal to the contact surface between the electrode and the welded laminate is a non-uniform shape smaller than the other dimension. Can be controlled. In particular, with regard to stress such as tensile stress, the “stress distribution exceeding the maximum tensile stress of the steel sheet” does not exist at the interface between the steel sheet base metal and the nugget and can be controlled to shift to the inside of the interface. . This can be well understood by comparing FIG. 4 (A) and FIG. 4 (B). FIG. 4A shows the relative relationship between the “interface” and “region of tensile stress exceeding the maximum tensile stress” in the case of spot welding in which the contact surface between the electrode and the laminate to be welded has a “non-uniform shape”. The positional relationship is shown in a plane transmission diagram. On the other hand, FIG. 4B shows the case of spot welding in which the contact surface between the electrode and the laminate to be welded is not “non-uniform” (particularly spot welding in which the contact surface is “circular” as in the prior art). The relative positional relationship between the “interface” and the “tensile stress region greater than or equal to the maximum tensile stress” is shown in a plane transparent view. Both are based on spot welding as shown in FIG. That is, the relative positional relationship between the “interface” shown in FIGS. 4 (A) and 4 (B) and the “tensile stress region greater than or equal to the maximum tensile stress” is the welded laminate in which the steel plate alignment gap 57 exists. This is based on an aspect in which the body 50 is spot-welded while being pressed by the spot welding electrode 20.
ここでいう「界面」とは、鋼板母材とナゲットとの界面（特に図４に示すように平面透過視における界面）のことを指しており、それゆえ、被溶接積層体においてナゲット（例えばスポット溶接後のナゲット）と鋼板との境目ポイントを示している。そして、「最大引張応力以上となる引張応力の領域」とは、広義には、スポット溶接に際して被溶接積層体に発生する応力に関して被溶接積層体又は鋼板の引張応力以上となる過度の応力のことを意味しており（ある見方で捉えるとスポット溶接後の被溶接積層体に残留し得る過度の応力）のことを指しており、狭義には、鋼板合せ間隙を有する被溶接積層体に対してスポット溶接を実施した後で得られる溶接鋼板にて遅れ破壊および／または疲労破壊などを誘発する要因となる応力（特に引張応力）のことを意味している。 The term “interface” as used herein refers to the interface between the steel plate base material and the nugget (particularly, the interface as seen in a plan view as shown in FIG. 4). This shows the boundary point between the welded nugget) and the steel plate. The term “tensile stress region above the maximum tensile stress” is, in a broad sense, excessive stress that exceeds the tensile stress of the welded laminate or steel plate with respect to the stress generated in the welded laminate during spot welding. (In a certain way, it refers to the excessive stress that can remain in the welded laminate after spot welding). It means stress (particularly tensile stress) that causes delayed fracture and / or fatigue fracture in a welded steel sheet obtained after spot welding.
図４（Ａ）および図４（ｂ）の双方とも「最大引張応力以上となる引張応力」の分布領域が斜線で示されている。図示するように“均一形状”の図４（Ｂ）では「最大引張応力以上となる引張応力」の斜線領域がより広範となっており、界面ポイントを含みつつそれを超えて大きく存在しているのに対して、“非均一形状”の図４（Ａ）では「最大引張応力以上となる引張応力」の斜線領域がより狭幅となっており、界面ポイントにまで至っていない。つまり、本発明に従った“非均一形状”の図４（Ａ）の場合、鋼板母材とナゲットとの界面に過度な応力の領域が存在しておらず、“均一形状”の図４（Ｂ）と比べると、かかる不都合な応力が界面よりも内側に偏移したと解すことができる。ここで、界面に「最大引張応力以上となる引張応力」が存在すると、遅れ破壊および／または疲労破壊などの誘因となり得る。つまり、引張応力などに代表される応力として大きい不都合な応力が鋼板母材とナゲットとの界面に含まれると、静的・動的疲労破壊を誘発する要因となり得る。この点、図４（Ａ）に示すように本発明においては鋼板母材とナゲットとの界面から避けるようにかかる応力の分布が位置付けられることになる。特に図５にも鑑みると、被溶接積層体を加圧しながらスポット溶接する際に発生する高い引張応力の分布がナゲットの径内に収まることによって割れ起点となりやすい「ナゲットの“際（きわ）”での局所的な応力集中」が本発明で抑制されるといえる。従って、本発明においては、遅れ破壊（例えば水素脆化による破壊）および／または疲労破壊の発生が抑制された溶接鋼板が最終的に得られることになる。 In both FIG. 4 (A) and FIG. 4 (b), the distribution region of “tensile stress equal to or greater than the maximum tensile stress” is indicated by hatching. As shown in the figure, in FIG. 4B of “uniform shape”, the hatched region of “tensile stress greater than or equal to the maximum tensile stress” is wider, and there is a large area beyond that including the interface point. On the other hand, in FIG. 4A of “non-uniform shape”, the hatched area of “tensile stress equal to or greater than the maximum tensile stress” is narrower and does not reach the interface point. That is, in the case of FIG. 4A of “non-uniform shape” according to the present invention, there is no region of excessive stress at the interface between the steel plate base material and the nugget, and FIG. Compared with B), it can be understood that such an inconvenient stress has shifted inward from the interface. Here, the presence of “tensile stress equal to or greater than the maximum tensile stress” at the interface can cause delayed fracture and / or fatigue fracture. That is, if an unfavorable stress as a stress typified by a tensile stress or the like is included in the interface between the steel plate base material and the nugget, it can be a factor inducing static / dynamic fatigue failure. In this regard, as shown in FIG. 4 (A), in the present invention, the distribution of stress applied so as to avoid from the interface between the steel plate base material and the nugget is positioned. In particular, in view of FIG. 5 as well, the “nugget” of “nugget”, which tends to be a starting point of cracking because the distribution of high tensile stress generated when spot welding is performed while pressing the laminate to be welded, is within the diameter of the nugget. It can be said that the "local stress concentration at" is suppressed by the present invention. Therefore, in the present invention, a welded steel sheet in which delayed fracture (for example, fracture due to hydrogen embrittlement) and / or fatigue fracture is suppressed is finally obtained.
本発明の製造方法において「互いに直交する方向の一方の寸法が他方の寸法より小さい非均一形状」としては、上述したように種々の形状が考えられ、例えば、楕円形、矩形または菱形（もしくは斜方形）などが挙げられる。ある好適な１つ態様でいえば、図６に示すように、接触面の形状１０が略楕円形状となっている。つまり、スポット溶接時の電極と被溶接積層体との接触部について平面視（平面透過視）の形状が略楕円形状となっていることが好ましい。 In the manufacturing method of the present invention, as the “non-uniform shape in which one dimension in a direction orthogonal to each other is smaller than the other dimension”, various shapes are conceivable as described above, for example, an ellipse, a rectangle, or a rhombus (or an oblique shape). Square). In one preferred embodiment, as shown in FIG. 6, the shape 10 of the contact surface is substantially elliptical. That is, it is preferable that the shape in plan view (plan view) of the contact portion between the electrode and the laminate to be welded during spot welding is substantially elliptical.
本明細書でいう「略楕円形状」とは、完全な楕円形であることに限らず、それから変更されつつも当業者の認識として依然“楕円”に通常含まれ得る形状をも含んでいる。本発明の観点でいえば、直交する短軸長さと長軸長さを有する形状であれば、楕円の曲部分の態様はいかなるものであってもよい。 The term “substantially elliptical shape” as used in the present specification is not limited to a perfect elliptical shape, but includes shapes that can be normally included in an “elliptical shape” as recognized by those skilled in the art while being changed therefrom. From the viewpoint of the present invention, as long as the shape has a short axis length and a long axis length perpendicular to each other, the shape of the elliptical curved portion may be any shape.
接触面の形状が略楕円形状となる態様では、例えば、図６に示すように電極先端部が楕円形態となった電極２０を用いてよい。あくまでも１つの例示にすぎないが、図示するように、電極先端部が切頭形状を有し、電極切頭面２８が楕円形となったガン電極２０を用いてよい。 In an aspect in which the shape of the contact surface is substantially elliptical, for example, an electrode 20 having an elliptical tip shape as shown in FIG. 6 may be used. Although it is only one example, the gun electrode 20 in which the electrode tip portion has a truncated shape and the electrode truncated surface 28 has an elliptical shape may be used as illustrated.
ある好適な態様では、“一方の寸法”が成す方向に沿って複数のナゲットが整列するようにスポット溶接を実施する。例えば図７に示すように、電極と被溶接積層体とが成す接触面の非均一形状１０につき、相対的に短い寸法に沿って複数のナゲット６０が整列するようにスポット溶接を逐次実施する。図示する態様から分かるように「複数のナゲットが整列するようにスポット溶接を実施する」とは、複数のスポット溶接によってもたらされる複数のナゲット６０が“一方の寸法ａが成す方向”、即ち、“相対的に短い寸法の方向”に沿って略整列していることを意味している。これは、スポット溶接時の電極と被溶接積層体との接触面の形状１０につき、ナゲットの配列方向に垂直な方向の長さがより短くなっていることを意味している。換言すれば、複数のナゲット６０の整列ラインと、“一方の寸法ａが成す方向”、即ち、“相対的に短い寸法の方向”とが略平行になっている。ここでいう「略平行」とは、完全に“平行”でなくてもよく、それから僅かにずれた態様であってもよい（例えばそれらが成す鋭角が０°よりも大きくかつ１０°以下となる態様であってもよい）ことを意味している。 In a preferred embodiment, spot welding is performed such that a plurality of nuggets are aligned along a direction defined by “one dimension”. For example, as shown in FIG. 7, spot welding is sequentially performed so that a plurality of nuggets 60 are aligned along a relatively short dimension with respect to the non-uniform shape 10 of the contact surface formed by the electrode and the laminate to be welded. As can be seen from the illustrated embodiment, “performing spot welding so that a plurality of nuggets are aligned” means that the plurality of nuggets 60 produced by the plurality of spot weldings are in the “direction in which one dimension a is formed”, that is, “ It means substantially aligned along the direction of “relatively short dimension”. This means that the length in the direction perpendicular to the arrangement direction of the nuggets is shorter with respect to the shape 10 of the contact surface between the electrode and the welded laminate during spot welding. In other words, the alignment lines of the plurality of nuggets 60 and the “direction of one dimension a”, that is, the “direction of a relatively short dimension” are substantially parallel. The term “substantially parallel” as used herein may not be completely “parallel” but may be slightly deviated therefrom (for example, the acute angle formed by them is greater than 0 ° and 10 ° or less). It may be an aspect).
“一方の寸法”が成す方向に沿って複数のナゲットが整列するようにスポット溶接を実施する場合、スポット溶接に際して応力が被溶接積層体に発生し易い。複数のナゲットが横並びで設けられることになるので、隣接するナゲット（即ち、接合部）に起因して、個々のナゲットでは、それと鋼板母材との界面で応力（特に引張応力）が生じやすい（図５を参照のこと）。この点、本発明では、そのような応力が発生したとしても、応力を制御して、鋼板母材とナゲットとの界面に対して「最大引張応力以上となる引張応力」の分布領域を外すことができる。つまり、本発明はかかる応力発生の不都合を好適に回避するように働くので、応力に起因する静的・動的疲労破壊の発生を減じることができる。換言すれば、「一方の寸法が成す方向に沿って複数のナゲットが整列するようにスポット溶接を実施する態様」では、特に本発明の応力の発生位置・分布領域の制御が功を奏しやすいといえる。 When spot welding is performed such that a plurality of nuggets are aligned along the direction of “one dimension”, stress is easily generated in the welded laminate during spot welding. Since a plurality of nuggets are provided side by side, stress (especially tensile stress) is likely to occur at the interface between the nugget and the steel plate base material due to adjacent nuggets (that is, joints) ( See FIG. In this regard, in the present invention, even if such a stress occurs, the stress is controlled to remove the distribution region of “tensile stress exceeding the maximum tensile stress” from the interface between the steel plate base material and the nugget. Can do. In other words, the present invention works to suitably avoid such inconvenience of stress generation, so that the occurrence of static / dynamic fatigue failure due to stress can be reduced. In other words, in the “embodiment in which spot welding is performed so that a plurality of nuggets are aligned along the direction in which one dimension is formed”, the control of the stress generation position / distribution region of the present invention is particularly effective. I can say that.
ここで、本発明の応力の発生位置・分布領域の制御が功をより奏しやすいといった観点でいえば、本発明に用いる鋼板は、いわゆる“高張力鋼板”および／または“高炭素含有鋼板”であってよい。これにつき詳述する。例えば自動車製造におけるスポット溶接を例にとると、鋼板はいわゆる“自動車鋼板”である。本発明で用いる鋼板の鋼材自体は、特に限定されるものでなく、炭素鋼、合金鋼、ニッケルクロム鋼、ニッケルクロムモリブデン鋼、クロム鋼、クロムモリブデン鋼、マンガン鋼などであってよい。また、代表的な鋼板の種類でいうと、被溶接板としての鋼板は、冷間圧延鋼板（ＳＰＣ材）、熱延鋼板、熱間圧延軟鋼板（ＳＰＨ材）、電気亜鉛めっき鋼板（ＳＥＣ材、ＳＥＨ材）、溶融亜鉛めっき鋼板（ＳＧＣ材、ＳＧＨ材）、溶融アルミめっき鋼板、塗装電気めっき鋼板、ステンレス鋼板（ＳＵＳ材）、アルミ板、銅板などであってよい。なお、鋼板の厚さは、特に制限はないものの、０．３ｍｍ以上１０ｍｍ以下、より限定すれば０．５ｍｍ以上５．０ｍｍ以下、更に限定すれば０．５ｍｍ以上２．０ｍｍ以下（１つ例示すれば、約１．６ｍｍ）であってよい。 Here, from the viewpoint that the control of the stress generation position / distribution region of the present invention is more effective, the steel plate used in the present invention is a so-called “high-tensile steel plate” and / or “high carbon-containing steel plate”. It may be. This will be described in detail. For example, taking spot welding in automobile manufacture as an example, the steel sheet is a so-called “automobile steel sheet”. The steel material itself of the steel plate used in the present invention is not particularly limited, and may be carbon steel, alloy steel, nickel chrome steel, nickel chrome molybdenum steel, chrome steel, chrome molybdenum steel, manganese steel, or the like. In terms of typical steel plate types, steel plates as welded plates include cold rolled steel plates (SPC materials), hot rolled steel plates, hot rolled mild steel plates (SPH materials), electrogalvanized steel plates (SEC materials). , SEH material), hot dip galvanized steel plate (SGC material, SGH material), hot dip galvanized steel plate, painted electroplated steel plate, stainless steel plate (SUS material), aluminum plate, copper plate and the like. The thickness of the steel plate is not particularly limited, but is 0.3 mm to 10 mm, more preferably 0.5 mm to 5.0 mm, and further limited to 0.5 mm to 2.0 mm (one example) About 1.6 mm).
本願発明者は、高強度の鋼板のスポット溶接において上述した如く鋼板母材との界面に応力（不都合な引張応力）が生じやすいことを見出した。特に、引張強度が高い鋼板はその傾向が見られやすく、それゆえ、高張力鋼板および／または高炭素含有鋼板を被溶接積層体として含むスポット溶接では、鋼板母材との界面に応力（特に不都合な引張応力）が生じやすいといえる。この点、本発明では、そのような応力が発生したとしても、応力の発生位置・分布領域を制御して、鋼板母材とナゲットとの界面から「最大引張応力以上となる引張応力」の分布領域を外すことができる。つまり、本発明は応力発生の不都合を好適に回避するように働くことになり、応力に起因する静的・動的疲労破壊の発生を減じることができる。換言すれば、“高張力鋼板”および／または“高炭素含有鋼板”を被溶接積層体に含むスポット溶接の態様」では、本発明の応力の発生位置・分布領域の制御が功を奏しやすいといえる。“高張力鋼板”および／または“高炭素含有鋼板”につき包括的に述べると、本発明では例えば０．２重量％の炭素含有量および９８０ＭＰａ以上の引張強さの少なくとも一方を有する鋼板を被溶接積層体として含むことが好ましい。炭素含有量の上限値は特に制限はないものの例えば１重量％であり、引張強さの上限値も特に制限はなく例えば２０００ＭＰａである。 The inventor of the present application has found that stress (inconvenient tensile stress) is likely to occur at the interface with the steel plate base material as described above in spot welding of a high-strength steel plate. In particular, steel plates with high tensile strength tend to show such a tendency. Therefore, in spot welding including a high-tensile steel plate and / or a high-carbon steel plate as a welded laminate, stress (particularly inconvenient) is applied to the interface with the steel plate base material. It can be said that a large tensile stress) is likely to occur. In this regard, in the present invention, even if such a stress occurs, the distribution and distribution of “tensile stress exceeding the maximum tensile stress” from the interface between the steel plate base material and the nugget is controlled by controlling the generation position / distribution region of the stress. The area can be removed. That is, the present invention works to suitably avoid the inconvenience of stress generation, and the occurrence of static / dynamic fatigue failure due to stress can be reduced. In other words, in the aspect of spot welding including “high-strength steel plate” and / or “high carbon-containing steel plate” in the welded laminate, the control of the stress generation position / distribution region of the present invention is likely to be effective. I can say that. Comprehensively describing “high-strength steel plate” and / or “high carbon-containing steel plate”, in the present invention, for example, a steel plate having at least one of a carbon content of 0.2 wt% and a tensile strength of 980 MPa or more is welded. It is preferable to include as a laminated body. The upper limit value of the carbon content is not particularly limited but is, for example, 1% by weight, and the upper limit value of the tensile strength is not particularly limited, for example, 2000 MPa.
同様に本発明の応力の発生位置・分布領域の制御が功をより奏しやすいという観点でいえば、スポット溶接前では被溶接積層体に鋼板合せ隙間が存在していてよい。例えば図８に示す如く、鋼板同士の間の鋼板接触部分５５に起因して鋼板合せ隙間５７が存在していてよい。かかる場合、図５に示すように鋼板合せ間隙５７が存在する被溶接積層体５０に対してスポット溶接電極２０で加圧しながらスポット溶接を行うことになり（加圧力は例えば０．５ｋＮ以上２０ｋＮ以下、より限定すれば１ｋＮ以上１０ｋＮ以下、１つ例示すると６．３ｋＮである）、被溶接積層体に応力がよりもたらされ易くなる（図５の態様では特に発明の理解のためにスポット溶接時の加圧で鋼板３０が撓む態様を示している）。この点、本発明では、そのような応力が発生したとしても、応力の発生位置・分布領域を制御して、鋼板母材とナゲットとの界面から「最大引張応力以上となる引張応力」の分布領域を外すことができる。つまり、本発明はかかる応力発生の不都合を回避するように働くことになり、応力に起因する静的・動的疲労破壊の発生を減じることができる。なお、本発明に関していう「鋼板合せ隙間」は、スポット溶接前の被溶接積層体における鋼板間の微小間隙を実質的に意味しており、鋼板接触部分５５に起因してもたらされるものに限らず、鋼板（鋼板材料）の公差によってもたらされる隙間であってもよい。鋼板合せ隙間につき、隙間高さ寸法（鋼板の積層方向に沿った隙間寸法）は、例えば０．５ｍｍ以上２．５ｍｍ以下であり、より限定すれば１．０ｍｍ以上２．０ｍｍ以下、更に限定すれば１．２ｍｍ以上１．６ｍｍ以下（１つ例示すると約１．４ｍｍ）である。一方、隙間幅寸法（鋼板の積層方向と直交する方向に沿った間隙寸法）は、２０ｍｍ以上６０ｍｍ以下であり、より限定すれば３０ｍｍ以上５０ｍｍ以下、更に限定すれば３５ｍｍ以上４５ｍｍ以下（１つ例示すると約４０ｍｍ）である。また、ここでいう「鋼板接触部分」は、被溶接積層体において鋼板間に存在して鋼板同士を橋渡しするものを意味しており、例えば鋼板接続部材（ナゲット、リベットおよび螺子部材など）である。ある１つの好適な態様にすぎないが、鋼板合せ隙間の幅方向（図８に示すように鋼板３０の主面に沿った方向）は、スポット溶接時の電極と被溶接積層体との接触面の「非均一形状」の“一方の寸法が成す方向”と略整合していてよい。つまり、鋼板合せ隙間の幅方向と、上記接触面の「非均一形状」における“相対的に短い寸法の方向”とが略平行となっていてよい。 Similarly, from the viewpoint that the control of the stress generation position / distribution region of the present invention is more effective, there may be a steel plate alignment gap in the welded laminate before spot welding. For example, as shown in FIG. 8, a steel plate alignment gap 57 may exist due to a steel plate contact portion 55 between the steel plates. In such a case, spot welding is performed while pressurizing with the spot welding electrode 20 to the welded laminate 50 in which the steel plate alignment gap 57 exists as shown in FIG. 5 (the applied pressure is not less than 0.5 kN and not more than 20 kN, for example) More specifically, it is 1 kN or more and 10 kN or less, and exemplarily one is 6.3 kN), and stress is more likely to be applied to the welded laminate (in the embodiment of FIG. This shows a mode in which the steel plate 30 is bent by the pressurization. In this regard, in the present invention, even if such a stress occurs, the distribution and distribution of “tensile stress exceeding the maximum tensile stress” from the interface between the steel plate base material and the nugget is controlled by controlling the generation position / distribution region of the stress. The area can be removed. That is, the present invention works so as to avoid such inconvenience of stress generation, and can reduce the occurrence of static / dynamic fatigue failure due to stress. The “steel plate alignment gap” as referred to in the present invention substantially means a minute gap between the steel plates in the welded laminate before spot welding, and is not limited to that caused by the steel plate contact portion 55. It may be a gap caused by a tolerance of a steel plate (steel plate material). The gap height dimension (gap dimension along the laminating direction of the steel sheets) is, for example, 0.5 mm or more and 2.5 mm or less, more specifically 1.0 mm or more and 2.0 mm or less. For example, it is 1.2 mm or more and 1.6 mm or less (one example is about 1.4 mm). On the other hand, the gap width dimension (gap dimension along the direction orthogonal to the laminating direction of the steel plates) is 20 mm or more and 60 mm or less, more preferably 30 mm or more and 50 mm or less, and further limited 35 mm or more and 45 mm or less (one example). Then, it is about 40 mm). Further, the “steel plate contact portion” here means a member that exists between the steel plates in the welded laminate and bridges the steel plates, and is, for example, a steel plate connecting member (nugget, rivet, screw member, etc.). . Although it is only one suitable aspect, the width direction (direction along the main surface of the steel plate 30 as shown in FIG. 8) is the contact surface between the electrode and the welded laminate during spot welding. The “non-uniform shape” of “a direction formed by one dimension” may be substantially aligned. That is, the width direction of the steel plate alignment gap and the “direction of relatively short dimension” in the “non-uniform shape” of the contact surface may be substantially parallel.
［本発明のスポット溶接電極］
次に、本発明のスポット溶接電極について説明する。本発明の電極は、上述のスポット溶接物の製造に好適な電極である。すなわち、本発明のスポット溶接電極では、互いに直交する方向の一方の寸法が他方の寸法よりも小さい非均一形状面が電極先端部に含まれている。
[Spot Welding Electrode of the Present Invention]
Next, the spot welding electrode of the present invention will be described. The electrode of this invention is an electrode suitable for manufacture of the above-mentioned spot weldment. That is, in the spot welding electrode of the present invention, the electrode tip portion includes a non-uniformly shaped surface in which one dimension in a direction perpendicular to each other is smaller than the other dimension.
本発明の電極は、その先端部の形状に特徴を有している。図９に示すように、電極先端部には、互いに直交する寸法ａおよび寸法ｂにつき寸法差を有する非均一形状面１０が含まれている。これは、スポット溶接時に被溶接積層体と接触する部分として互いに直交する方向の一方の寸法が他方の寸法よりも小さい非均一形状面を電極が含んでいることを意味している。 The electrode of the present invention is characterized by the shape of its tip. As shown in FIG. 9, the electrode tip portion includes a non-uniformly shaped surface 10 having a dimensional difference between a dimension a and a dimension b orthogonal to each other. This means that the electrode includes a non-uniformly shaped surface in which one dimension in a direction perpendicular to each other is smaller than the other dimension as a portion that contacts the welded laminate during spot welding.
ここでいう「互いに直交する方向の一方の寸法が他方の寸法よりも小さい非均一形状面が電極先端部に含まれている」は、広義には、電極先端部の平面視形状の直交寸法が互いに異なることを意味しており、狭義には、電極の長手方向（電極高さ方向）に直交する平面における電極先端部の形状が異方形となっていることを意味している。かかる直交平面における電極先端部の形状は、図９に示す如く互いに直交する方向の一方の寸法ａと他方の寸法ｂとを比べた場合、一方の寸法ａが他方の寸法ｂよりも小さくなっている。本発明でいう「電極先端部」とは、図９に示すように、電極最先端に向かってテーパ状に幅寸法が減じられる部分を指している。図示する態様でいえば、テーパ開始ポイント２５ａから電極最先端ポイント２５ｂにまで至る局所的部分が電極先端部に相当する。 Here, “the electrode tip includes a non-uniformly shaped surface in which one dimension in a direction perpendicular to each other is smaller than the other dimension” means that the orthogonal dimension of the shape of the electrode tip in plan view is broadly defined. This means that they are different from each other, and in a narrow sense, it means that the shape of the tip of the electrode in a plane perpendicular to the longitudinal direction (electrode height direction) of the electrode is anisotropic. The shape of the tip of the electrode in the orthogonal plane is such that when one dimension a and the other dimension b in the directions orthogonal to each other are compared as shown in FIG. 9, one dimension a is smaller than the other dimension b. Yes. As shown in FIG. 9, the “electrode tip” in the present invention refers to a portion where the width dimension is reduced in a tapered shape toward the tip of the electrode. In the illustrated embodiment, a local portion from the taper start point 25a to the electrode tip point 25b corresponds to the electrode tip.
図示する態様から分かるように、本発明のスポット溶接電極でいう“非均一形状面”は、電極先端部の断面図における形状に関しており、それゆえ、本発明のスポット溶接電極は、テーパ開始ポイント２５ａから電極最先端ポイント２５ｂまでの局所的部分の断面形状が“非均一形状”となっている。換言すれば、本発明のスポット溶接電極では、電極高さ方向と直交する面で切り取った電極先端部の断面形状が「互いに直交する方向の一方の寸法が他方の寸法よりも小さい非均一形状」となっている。 As can be seen from the illustrated embodiment, the “non-uniformly shaped surface” referred to in the spot welding electrode of the present invention relates to the shape in the sectional view of the electrode tip, and therefore the spot welding electrode of the present invention has a taper start point 25a. The cross-sectional shape of the local portion from the electrode tip point 25b to the electrode tip point 25b is a “non-uniform shape”. In other words, in the spot welding electrode of the present invention, the cross-sectional shape of the electrode tip portion cut by a plane orthogonal to the electrode height direction is “a non-uniform shape in which one dimension in the direction orthogonal to each other is smaller than the other dimension” It has become.
本発明のスポット溶接電極に関して「一方の寸法ａが他方の寸法ｂよりも小さい非均一形状面」は、種々のものが考えられ、例えば図９に示すように楕円形、矩形または菱形（もしくは斜方形）であってよい。“楕円形”は図９の最下左に示すように互いに直交する短径長さａ１と長径長さｂ１とから成る非均一形状である。“矩形”は図９の最下中央に示すように互いに直交する短軸長さａ２と長軸長さｂ２とから成る非均一形状である。“菱形”／“斜方形”は図９の最下右に示すように互いに直交する短軸長さａ３と長軸長さｂ３とから成る４辺が等しい四角形の非均一形状である。本発明のスポット溶接電極は、その電極先端部に非均一形状面を含んでいるので、スポット溶接に際して被溶接積層体に生じる応力を好適に制御することができる。つまり、被溶接積層体に生じる応力の分布を好適に偏移させることができ、鋼板母材とナゲットとの界面を避けるように「最大引張応力以上となる引張応力」の発生位置・分布領域を制御できる（図４（Ａ）および４（Ｂ）参照）。 Regarding the spot welding electrode of the present invention, “a non-uniformly shaped surface in which one dimension“ a ”is smaller than the other dimension“ b ”may be various, for example, as shown in FIG. Square). The “elliptical shape” is a non-uniform shape composed of a minor axis length a 1 and a major axis length b 1 which are orthogonal to each other, as shown at the bottom left of FIG. “Rectangle” is a non-uniform shape composed of a short axis length a 2 and a long axis length b 2 orthogonal to each other as shown in the lowermost center of FIG. “Rhombus” / “rhombic” is a non-uniform shape of a quadrangle having the same four sides composed of a short axis length a 3 and a long axis length b 3 which are orthogonal to each other, as shown at the bottom right in FIG. Since the spot welding electrode of the present invention includes a non-uniformly shaped surface at the electrode tip, the stress generated in the welded laminate during spot welding can be suitably controlled. In other words, the distribution of the stress generated in the welded laminate can be suitably shifted, and the generation position / distribution area of “tensile stress exceeding the maximum tensile stress” is set so as to avoid the interface between the steel plate base material and the nugget. It can be controlled (see FIGS. 4A and 4B).
ある好適な態様では、電極先端部が切頭形状を有し、電極切頭面が非均一形状面となっている。例えば図１０（Ａ）〜１０（Ｃ）に示すように、スポット溶接電極２０が切頭型の電極となっており、その切頭面２８が非均一形状面を成している。つまり、“切頭型”の場合、本発明のスポット溶接電極は、その最先端面が非均一形状面（互いに直交する寸法につき一方の寸法が他方の寸法よりも小さい非均一形状面）となっている。図１０（Ａ）は切頭面２８が短径長さａ１と長径長さｂ１とから成る楕円形状面となっており、図１０（Ｂ）は切頭面２８が互いに直交する短軸長さａ２と長軸長さｂ２とから成る矩形状面となっており、図１０（Ｃ）は切頭面２８が互いに直交する短軸長さａ３と長軸長さｂ３とから成る菱形状面・斜方形面となっている。 In a preferred aspect, the electrode tip portion has a truncated shape, and the electrode truncated surface has a non-uniformly shaped surface. For example, as shown in FIGS. 10A to 10C, the spot welding electrode 20 is a truncated electrode, and the truncated surface 28 forms a non-uniformly shaped surface. In other words, in the case of the “truncated type”, the spot welding electrode of the present invention has a non-uniformly shaped surface (a non-uniformly shaped surface in which one dimension is smaller than the other dimension with respect to dimensions perpendicular to each other). ing. 10A, the truncated surface 28 is an elliptical surface having a minor axis length a 1 and a major axis length b 1, and FIG. 10B is a minor axis in which the truncated surfaces 28 are orthogonal to each other. has a rectangular surface having a length a 2 and major axis b 2 Prefecture, FIG 10 (C) and the minor axis length a 3 and major axis b 3 that truncated surfaces 28 are perpendicular to each other It has a rhombus-shaped surface and an oblique surface.
特に図１０（Ａ）の電極は、切頭面２８が略楕円形を有するが、“楕円”がそもそも角張った形状でなく、その点で図１０（Ｂ）および１０（Ｃ）と区別され得る。図１０（Ａ）に示すスポット溶接電極２０は、その電極先端部の「互いに直交する方向の一方の寸法が他方の寸法よりも小さい非均一形状面」が略楕円形となっている。ここでいう「略楕円形」とは、上述した如く、完全な楕円形に限らず、それから変更されつつも当業者の認識として依然“楕円”に通常含まれる形状を含んでいる（つまり、直交する短軸長さと長軸長さを有する形状であれば、楕円の曲部分の態様はいかなるものであってもよい）。あくまでも一例であるが、本発明のスポット溶接電極２０に係る略楕円形状の切頭面２８は、好ましくは短径長さａ１が長径長さｂ１の５０％以上８３％以下となっている。また、本発明のスポット溶接電極２０に係る略楕円形状の切頭面２８は、好ましくは長径長さｂ１が６ｍｍ以上８ｍｍ以下となっている。このような態様の溶接電極を用いると、スポット溶接に際して被溶接積層体に生じる応力をより好適に制御できる。つまり、被溶接積層体に生じる応力の分布を好適に偏移させることができ、鋼板母材とナゲットとの界面を避けるように「最大引張応力以上となる引張応力」の発生位置・分布領域が制御され得る。 In particular, in the electrode of FIG. 10A, the truncated surface 28 has a substantially oval shape, but the “ellipse” is not an angular shape in the first place, and can be distinguished from FIGS. 10B and 10C in that respect. . The spot welding electrode 20 shown in FIG. 10 (A) has a substantially elliptical shape in which “one non-uniformly shaped surface in which one dimension in a direction orthogonal to each other is smaller than the other dimension” of the electrode tip. The “substantially elliptical shape” as used herein is not limited to a perfect elliptical shape as described above, but includes a shape that is usually included in an “ellipse” as recognized by those skilled in the art, although it is changed from that. As long as the shape has a short axis length and a long axis length, the shape of the ellipsoidal curved portion may be any). Although merely one example, the truncated surface 28 of the substantially elliptical shape of the spot welding electrodes 20 of the present invention are preferably short necked length a 1 is less than or equal to 83% to 50% or more of major axis length b 1 . Further, a substantially elliptical shape of a truncated surface 28 of the spot welding electrodes 20 of the present invention, preferably the major axis length b 1 is a 6mm or 8mm or less. If the welding electrode of such an aspect is used, the stress which arises in a to-be-welded laminated body at the time of spot welding can be controlled more suitably. In other words, the distribution of stress generated in the laminate to be welded can be suitably shifted, and the generation position / distribution region of “tensile stress exceeding the maximum tensile stress” is set so as to avoid the interface between the steel plate base material and the nugget. Can be controlled.
本発明のスポット溶接電極の先端部は、“切頭面”を有する形態に特に限定されるものではない。図１１に示すように、切頭面を有さないようにスポット溶接電極２０の先端部にて電極幅寸法が電極最先端まで漸次減じられた形態を本発明のスポット溶接電極が有していてもよい。つまり、電極高さ方向と直交する面で切り取った電極先端部の断面形状面が「互いに直交する方向の一方の寸法が他方の寸法よりも小さい非均一形状面」となっていれば、電極と被溶接積層体との接触面が“非均一形状”となるので、スポット溶接に際して被溶接積層体に生じる応力を好適に制御できる。よって、被溶接積層体に生じる応力の分布を好適に偏移させることができ、鋼板母材とナゲットとの界面を避けるように「最大引張応力以上となる引張応力」の発生位置・分布領域を制御できる。図１１においては、電極高さ方向と直交する面で切り取った電極先端部の２つの断面Ｉおよび断面ＩＩの双方とも“非均一形状面”となっている。 The tip of the spot welding electrode of the present invention is not particularly limited to a form having a “truncated surface”. As shown in FIG. 11, the spot welding electrode of the present invention has a configuration in which the electrode width dimension is gradually reduced to the tip of the electrode so that it does not have a truncated surface. Also good. In other words, if the cross-sectional shape surface of the electrode tip portion cut by a surface orthogonal to the electrode height direction is “a non-uniform shape surface in which one dimension in the direction orthogonal to each other is smaller than the other dimension”, Since the contact surface with the welded laminate has a “non-uniform shape”, the stress generated in the welded laminate during spot welding can be suitably controlled. Therefore, the distribution of the stress generated in the welded laminate can be shifted favorably, and the generation position / distribution area of “tensile stress exceeding the maximum tensile stress” can be set so as to avoid the interface between the steel plate base material and the nugget. Can be controlled. In FIG. 11, both of the two cross sections I and II of the electrode tip portion cut by a plane orthogonal to the electrode height direction are “non-uniformly shaped surfaces”.
本発明のスポット溶接電極の材質は、常套的な溶接ガン電極と同様であってよい。あくまでも例示にすぎないが、例えば、本発明ののスポット溶接電極の電極材質は、アルミナ分散銅、クロム銅およびクロムジルコニウム銅から成る群から選択される少なくとも１種であってよい。また、本発明のスポット溶接電極は、電極先端部と電極胴部とが一体化して成る“一体型”に特に限定されず、電極先端部を取り替えることができる“キャップ型”であってもよい。“キャップ型”の場合、電極チップが消耗した際の廃棄部品をより減じることができる。 The material of the spot welding electrode of the present invention may be the same as a conventional welding gun electrode. For example, the electrode material of the spot welding electrode of the present invention may be at least one selected from the group consisting of alumina-dispersed copper, chromium copper, and chromium zirconium copper. Further, the spot welding electrode of the present invention is not particularly limited to the “integrated type” in which the electrode tip and the electrode body are integrated, and may be a “cap type” in which the electrode tip can be replaced. . In the case of the “cap type”, it is possible to further reduce the number of waste parts when the electrode tip is consumed.
本発明の電極のより詳細な事項、更なる具体的な態様、または使用時の態様などその他の事項は、上述の［本発明の製造方法］で説明しているので、重複を避けるためにここでの説明は省略する。なお、本発明の電極を備えたスポット溶接装置についていえば、それは、常套的なスポット溶接機と同様の加圧・通電部、電源部、電力制御部および接続用のケーブル類などから構成されていてよい（つまり、溶接ガン電極以外の各種の装置要素は常套的なものであってよい）。また、かかる溶接装置は、その全体として捉えた装置タイプにつき、“定置形スポット溶接機”、“卓上形スポット溶接機”、“ポータブルスポット溶接機”または“マルチスポット溶接機”のいずれのタイプであってもよい。 Other matters, such as more detailed matters, further specific aspects, or usage aspects of the electrode of the present invention are described in the above [Production method of the present invention]. The description in is omitted. As for the spot welding apparatus provided with the electrode of the present invention, it is composed of a pressurizing / energizing unit, a power source unit, a power control unit, and cables for connection similar to a conventional spot welding machine. (I.e., various device elements other than the welding gun electrode may be conventional). In addition, such welding equipment can be of any type, such as “stationary spot welder”, “desktop spot welder”, “portable spot welder” or “multi-spot welder”. There may be.
以上、本発明の実施態様について説明してきたが、本発明の適用範囲における典型例を示したに過ぎない。したがって、本発明は、上記の実施形態に限定されず、種々の変更がなされ得ることは当業者に容易に理解されよう。 The embodiments of the present invention have been described above, but only typical examples within the scope of the present invention are shown. Therefore, it will be easily understood by those skilled in the art that the present invention is not limited to the above-described embodiment, and various modifications can be made.
例えば、上記においては、一対のスポット溶接電極の各々につき、被溶接積層体との接触面が“非均一形状”となる態様を中心に説明してきたが、本発明はかかる態様に限定されない。例えば、一対のスポット溶接電極のいずれか一方のみ（すなわち、対を成す２つの電極のうちのいずれか１つの電極のみ）が、被溶接積層体との間で“非均一形状”の接触面となるような態様であってもよい。 For example, in the above description, the aspect in which the contact surface with the welded laminate has a “non-uniform shape” has been described for each of the pair of spot welding electrodes, but the present invention is not limited to such an aspect. For example, only one of the pair of spot welding electrodes (that is, only one of the two electrodes in a pair) is contacted with the contact surface having a “non-uniform shape” with the welded laminate. The aspect which becomes may be sufficient.
また、上記においては、“抵抗スポット溶接”によって溶接物を得る態様を中心に説明してきたが、本発明はかかる態様に限定されない。例えば、被溶接板表面の溶接箇所となる部分に突起を設ける“プロジェクション溶接”であってもよく、あるいは、接合面にろう材を設置して抵抗発熱でろう付けを行う“抵抗ろう付け”の態様などであってもよい。 In the above description, the description has been focused on the aspect of obtaining the welded material by “resistance spot welding”, but the present invention is not limited to such an aspect. For example, it may be “projection welding” in which protrusions are provided on the welded portion of the surface of the plate to be welded, or “resistance brazing” in which a brazing material is placed on the joint surface and brazing is performed by resistance heating. An aspect etc. may be sufficient.
本発明に関連する実施例を説明する。 Examples relating to the present invention will be described.
以下の条件のスポット溶接についてシミュレーションを実施した（図５および図８参照）。
（被溶接積層体）
・鋼板枚数：２枚
・鋼板厚さ：各１．６ｍｍ
・鋼板合せ間隙：１．４ｍｍ
・鋼板の全板幅：１００ｍｍ
・鋼板の板奥行き：５０ｍｍ
・スポット溶接位置：鋼板１００ｍｍ×５０ｍｍの中央ポイント
・鋼板の材料強度：１３００ＭＰａ
・鋼板合せ隙間の幅寸法（隙間幅寸法）：４０ｍｍ
（実施例のスポット溶接プロセス）
シミュレーションで想定したスポット溶接態様は図５に示される。まず、図５（ｉ）に示すように、２枚の鋼板３０を重ね合わせた被溶接積層体５０を前提とする。図示するように２枚の鋼板３０の間には接続部分／鋼板接触部分５５（例えば既に形成されたナゲット部など）に起因して鋼板合せ間隙５７が存在する。かかる被溶接積層体５０を一対のスポット溶接電極２０で挟み込んでスポット溶接を行う。具体的には、電極間で通電路が形成されるように、図５（ｉｉ）に示すように被溶接積層体５０の対向する外面にそれぞれ当接するように同一の溶接電極２０で被溶接積層体５０を挟み込み、その状態でスポット溶接を行う。かかるスポット溶接に際しては一対のスポット溶接電極２０から被溶接積層体５０に対して外側から内側に向かって加圧力（より具体的には鋼板の積層方向に沿って被溶接積層体の外側から内側へと向かう加圧力）が加えられるが、その際の加圧力は６．３ｋＮとした。かかる加圧力に起因して、図５（ｉｉｉ）に示すようにスポット溶接時に鋼板３０は局所的・部分的に撓むことになる。
A simulation was performed for spot welding under the following conditions (see FIGS. 5 and 8).
(Welded laminate)
-Number of steel plates: 2-Steel plate thickness: 1.6 mm each
・ Steel plate gap: 1.4mm
・ Full width of steel plate: 100mm
・ Plate depth of steel plate: 50mm
-Spot welding position: Central point of steel plate 100 mm x 50 mm-Material strength of steel plate: 1300 MPa
・ Width dimension of gap between steel plates (gap width dimension): 40mm
(Example spot welding process)
The spot welding mode assumed in the simulation is shown in FIG. First, as shown in FIG. 5 (i), it is assumed that a welded laminate 50 in which two steel plates 30 are overlapped. As shown in the drawing, a steel plate alignment gap 57 exists between the two steel plates 30 due to the connection portion / steel plate contact portion 55 (for example, a nugget portion already formed). The welded laminate 50 is sandwiched between a pair of spot welding electrodes 20 to perform spot welding. Specifically, as shown in FIG. 5 (ii), the same welding electrode 20 is used to laminate the welded layers so as to make contact with the opposing outer surfaces of the welded laminate 50 so that a current path is formed between the electrodes. The body 50 is sandwiched and spot welding is performed in this state. In such spot welding, a pressure is applied from the pair of spot welding electrodes 20 to the welded laminate 50 from the outside to the inside (more specifically, from the outside to the inside of the laminate to be welded along the laminating direction of the steel plates). Applied pressure), and the applied pressure at that time was set to 6.3 kN. Due to the applied pressure, as shown in FIG. 5 (iii), the steel plate 30 is locally and partially bent during spot welding.
シミュレーション結果を図１２に示す。図１２に示すグラフおよび表は、接触面形状（スポット溶接時の電極と被溶接積層体との接触面の平面視形状）と、「最大引張応力以上となる引張応力」の分布領域（最大引張応力以上となる長手方向の引張応力分布長さ）との相関関係を示している。かかる図１２から下記事項を把握することができる。
・電極と被溶接積層体との接触面として一方の寸法が他方の寸法よりも小さい“非均一形状”の場合、被溶接積層体にもたらされる「最大引張応力以上となる引張応力」の分布が鋼板母材とナゲットとの界面よりも内側に位置付けられる。
・電極と被溶接積層体との接触面として一方の寸法（短径長さ）が他方の寸法（長径長さ）の５０％以上８３％以下となる“非均一形状”の場合に応力分布の偏移効果がより明確にみられる。
・同様にして電極と被溶接積層体との接触面として他方の寸法（長径長さ）が６ｍｍ以上８ｍｍ以下となる“非均一形状”の場合に応力分布の偏移効果がより明確にみられる。
The simulation result is shown in FIG. The graph and table shown in FIG. 12 show the contact surface shape (planar shape of the contact surface between the electrode and the laminate to be welded during spot welding) and the distribution region (maximum tensile stress equal to or greater than the maximum tensile stress). It shows the correlation with the tensile stress distribution length in the longitudinal direction that is greater than or equal to the stress. The following items can be grasped from FIG.
・ When one dimension is smaller than the other dimension as the contact surface between the electrode and the welded laminate, the distribution of “tensile stress exceeding the maximum tensile stress” provided to the welded laminate is It is positioned inside the interface between the steel plate base material and the nugget.
-Stress distribution in the case of a "non-uniform shape" where one dimension (minor axis length) is 50% or more and 83% or less of the other dimension (major axis length) as the contact surface between the electrode and the welded laminate The shift effect is more clearly seen.
Similarly, the effect of shifting the stress distribution is more clearly seen when the other dimension (major axis length) is 6 mm or more and 8 mm or less as the contact surface between the electrode and the laminate to be welded. .
以上の如く、本発明に従ってスポット溶接を実施すれば、「最大引張応力以上となる引張応力」が鋼板母材とナゲットとの界面に存在せず、かかる界面よりも内側に不都合な応力を偏移させることができることが分かった。つまり、本発明に従って得られた溶接物は、静的・動的疲労破壊を誘発する要因が減じられ、長期疲労強さにより優れた溶接鋼板となり得る。 As described above, when spot welding is performed according to the present invention, there is no “tensile stress exceeding the maximum tensile stress” at the interface between the steel plate base material and the nugget, and inconvenient stress is shifted to the inside of the interface. I found out that That is, the welded article obtained according to the present invention can be a welded steel sheet that has reduced factors that induce static and dynamic fatigue failure and is superior in long-term fatigue strength.
本発明の製造方法およびスポット溶接電極は、例えば自動車の車体製造に用いることができ、より具体的には鋼板同士の溶接に用いることができる。特に、本発明では、遅れ破壊および／または疲労破壊などの誘因が減じられるので、その利用価値は高いといえる。 The production method and spot welding electrode of the present invention can be used, for example, for the production of automobile bodies, and more specifically, can be used for welding steel plates. In particular, in the present invention, since the incentive such as delayed fracture and / or fatigue fracture is reduced, it can be said that its utility value is high.
また、本発明は、特に自動車製造の分野に限ることはなく、溶接が必要とされる他の製造業分野で利用することもできる。あくまでも例示にすぎないが、例えば自動二輪、トラック、トラクター、造船、大型容器製造、高層ビル鉄骨、各種金属製品・電化製品などの種々の製造業分野で本発明を利用できる。 Further, the present invention is not particularly limited to the field of automobile manufacturing, and can be used in other manufacturing industries where welding is required. The present invention can be used in various fields of manufacturing such as motorcycles, trucks, tractors, shipbuilding, large-scale container manufacturing, high-rise building steel frames, various metal products / electrical appliances, and the like.
１０ 電極と被溶接積層体との接触面の形状／非均一形状面
２０ 電極（スポット溶接に用いる電極／溶接ガン電極）
２５ａ テーパ開始ポイント
２５ｂ 電極最先端ポイント
２８ 電極切頭面
３０ 鋼板
５０ 被溶接積層体
５５ 鋼板接触部分
５７ 鋼板合せ隙間
６０ ナゲット
10 Shape of contact surface between electrode and welded laminate / non-uniformly shaped surface 20 Electrode (electrode used for spot welding / welding gun electrode)
25a Taper start point 25b Electrode cutting edge point 28 Electrode truncated surface 30 Steel plate 50 Laminate to be welded 55 Steel plate contact portion 57 Steel plate alignment gap 60 Nugget
Claims (10)
少なくとも２枚の鋼板を重ね合わせて得られる被溶接積層体を一対の電極で加圧しながら通電を行うスポット溶接において、該電極と該被溶接積層体との接触面は、互いに直交する方向の一方の寸法が他方の寸法より小さい非均一形状を有する、スポット溶接物の製造方法。 A method of manufacturing a spot weldment, comprising:
In spot welding in which energization is performed while pressing a welded laminate obtained by stacking at least two steel plates with a pair of electrodes, the contact surface between the electrode and the welded laminate is in one direction orthogonal to each other. A method of manufacturing a spot welded article, which has a non-uniform shape that is smaller than the other dimension.
互いに直交する方向の一方の寸法が他方の寸法よりも小さい非均一形状面が電極先端部に含まれる、スポット溶接電極。 An electrode used for spot welding,
A spot welding electrode in which a non-uniformly shaped surface in which one dimension in a direction perpendicular to each other is smaller than the other dimension is included in the electrode tip.
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| WO2012036262A1 (en) * | 2010-09-16 | 2012-03-22 | 住友金属工業株式会社 | Molded member and manufacturing method thereof |
| WO2014045431A1 (en) * | 2012-09-24 | 2014-03-27 | 新日鐵住金株式会社 | Spot welding method for high-strength steel sheet excellent in joint strength |
| JP2014087220A (en) * | 2012-10-25 | 2014-05-12 | Neturen Co Ltd | Power-supplying device |
| JP2016083676A (en) * | 2014-10-24 | 2016-05-19 | 株式会社神戸製鋼所 | Spot welding method |
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| WO2012036262A1 (en) * | 2010-09-16 | 2012-03-22 | 住友金属工業株式会社 | Molded member and manufacturing method thereof |
| WO2014045431A1 (en) * | 2012-09-24 | 2014-03-27 | 新日鐵住金株式会社 | Spot welding method for high-strength steel sheet excellent in joint strength |
| JP2014087220A (en) * | 2012-10-25 | 2014-05-12 | Neturen Co Ltd | Power-supplying device |
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