JP6079466B2 - Lap welded member of high strength steel plate and method for producing the same - Google Patents
Lap welded member of high strength steel plate and method for producing the same Download PDFInfo
- Publication number
- JP6079466B2 JP6079466B2 JP2013128737A JP2013128737A JP6079466B2 JP 6079466 B2 JP6079466 B2 JP 6079466B2 JP 2013128737 A JP2013128737 A JP 2013128737A JP 2013128737 A JP2013128737 A JP 2013128737A JP 6079466 B2 JP6079466 B2 JP 6079466B2
- Authority
- JP
- Japan
- Prior art keywords
- longitudinal direction
- weld
- lap
- steel plate
- lap weld
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Landscapes
- Resistance Welding (AREA)
- Laser Beam Processing (AREA)
- Heat Treatment Of Articles (AREA)
- Body Structure For Vehicles (AREA)
Description
本発明は、高強度鋼板の重ね溶接部材およびその製造方法に関する。 The present invention relates to a lap weld member of a high-strength steel plate and a method for manufacturing the same.
衝突安全性の向上と燃費の向上とを両立するため、自動車車体を構成するモノコックボディの骨格をなす構造部材（以下、「自動車用構造部材」という）への高強度鋼板の適用が拡大している。現在、自動車用構造部材には引張強度が９８０ＭＰａ級の高張力鋼板が用いられており、さらに、最近は引張強度が１１８０ＭＰａ級以上の高張力鋼板の適用も検討されている。また、プレス成形と同時に焼入れを行うホットスタンプ法を用いることにより引張強度が１５００ＭＰａ以上の高強度の自動車用構造部材の製造も進められている。ホットスタンプ法によれば、鋼板が高温の軟質な状態でプレス成形を行うために成形後の寸法精度に関する問題の発生が少ないとともに、高温かつ高延性の状態でプレス成形を行うことができることから成形性に優れるという大きなメリットがある。 In order to achieve both improved collision safety and improved fuel efficiency, the application of high-strength steel sheets to structural members that form the framework of the monocoque body that constitutes the body of an automobile (hereinafter referred to as “structural members for automobiles”) has expanded. Yes. Currently, high-strength steel sheets having a tensile strength of 980 MPa are used for structural members for automobiles, and recently, application of high-tensile steel sheets having a tensile strength of 1180 MPa or more is also being studied. In addition, the production of high-strength automotive structural members having a tensile strength of 1500 MPa or more has been promoted by using a hot stamp method in which quenching is performed simultaneously with press molding. According to the hot stamping method, the steel sheet is pressed in a soft state at a high temperature, so that there is little problem with dimensional accuracy after forming, and press forming can be performed in a high temperature and high ductility state. There is a great merit that it is excellent in performance.
一般的に、自動車用構造部材は、これら鋼板の成形品をスポット溶接により他の成形品と溶接することにより構築される。しかし、１１８０ＭＰａ以上の高張力鋼板やホットスタンプ鋼板などの高強度鋼板の母材は、焼入れにより強化されているため、スポット溶接を行うとスポット溶接部の熱影響部（ＨＡＺ）が焼き戻しを受け、母材よりも軟化する。ＨＡＺの軟化（以下、「ＨＡＺ軟化」ともいう）は、例えば５９０ＭＰａ鋼板では殆ど問題にならなかったものの、９８０ＭＰａ鋼板では認められ、特に水冷機能を有する連続焼鈍設備（ＷＱ−ＣＡＬ）でマルテンサイト組織とされた１１８０ＭＰａ以上の高張力鋼板やホットスタンプ鋼板のスポット溶接部のＨＡＺにおいて著しく発生する。例えば、１１８０ＭＰａ級の冷延鋼板では母材の硬度はビッカース硬さＨｖ３７０から４２０程度であるのに対し、ＨＡＺの最軟化部の硬度はＨｖ３００程度にまで低下する。 Generally, the structural member for automobiles is constructed by welding a molded product of these steel plates to other molded products by spot welding. However, the base material of high-strength steel plates such as high-strength steel plates and hot stamped steel plates of 1180 MPa or higher is strengthened by quenching, so that when spot welding is performed, the heat-affected zone (HAZ) of the spot welded portion is tempered. Softer than the base material. Although softening of HAZ (hereinafter also referred to as “HAZ softening”) hardly occurred in, for example, a 590 MPa steel plate, it was recognized in a 980 MPa steel plate, and in particular, a martensite structure in a continuous annealing facility (WQ-CAL) having a water cooling function. It occurs remarkably in the HAZ of spot welds of high-tensile steel plates and hot stamped steel plates of 1180 MPa or higher. For example, in a 1180 MPa grade cold-rolled steel sheet, the hardness of the base material is about Vickers hardness Hv 370 to 420, whereas the hardness of the most softened portion of the HAZ is reduced to about Hv 300.
図１２は、高強度鋼板からなる部材（１５００ＭＰａ級のホットスタンプ鋼板部材）のスポット溶接部の硬さ分布の一例を示すグラフである。 FIG. 12 is a graph showing an example of the hardness distribution of the spot welded portion of a member made of a high-strength steel plate (1500 MPa class hot stamped steel plate member).
図１２のグラフに示すように、１５００ＭＰａ級のホットスタンプ材の場合には、母材はビッカース硬さＨｖ４５０程度であるが、ＨＡＺの最軟化部はＨｖ３００程度となり、ＨＡＺの最軟化部は母材よりもＨｖ１５０程度低下する。 As shown in the graph of FIG. 12, in the case of a 1500 MPa class hot stamp material, the base material has a Vickers hardness of about Hv450, but the HAZ softest part is about Hv300, and the HAZ softest part is the base material. Hv is reduced by about 150.
図１３は、図１２に示すスポット溶接部の硬さ分布を有するホットスタンプ鋼板部材が、ＨＡＺ最軟化部を起点として破断した状況を示す説明図であり、図１３（ａ）は上面図、図１３（ｂ）は断面図である。 FIG. 13 is an explanatory view showing a state in which the hot stamped steel plate member having the hardness distribution of the spot welded portion shown in FIG. 12 is broken starting from the HAZ most softened portion, and FIG. 13 (a) is a top view, FIG. 13 (b) is a sectional view.
このようなＨＡＺ軟化は、スポット溶接の継手評価である、引張せん断試験、および十字引張試験の結果には影響しないものの、スポット溶接部を含んだホットスタンプの部品のフランジ部全体に引張荷重が負荷されると、図１３（ａ）および図１３（ｂ）に示すように、ＨＡＺ最軟化部に局所的にひずみが集中して破断することがある。このように、１１８０ＭＰａ以上の鋼板のプレス成形品におけるスポット溶接部のＨＡＺ軟化は、衝突時にプレス成形品の破断の起点となることがある。 Although this HAZ softening does not affect the results of the tensile shear test and cross tension test, which are joint evaluations of spot welding, a tensile load is applied to the entire flange portion of the hot stamping part including the spot weld. Then, as shown in FIGS. 13 (a) and 13 (b), strain may concentrate locally on the HAZ softest part and break. As described above, the HAZ softening of the spot welded portion in the press-formed product of a steel plate of 1180 MPa or more may be a starting point of the fracture of the press-formed product at the time of collision.
例えばＡピラー，Ｂピラー，ルーフレール，サイドシルといった、閉じた横断面を有するとともにこの横断面を成すためにスポット溶接されるフランジを備える自動車車体の筒状の構造部材は、自動車の衝突時に破断することなく塑性変形することにより、衝撃エネルギーを効果的に吸収してキャビン内の乗客を保護することを求められる。しかしながら、厳しい衝突モードの場合、例えば、米国道路安全保険協会（ＩＩＨＳ）のＳＵＶ側面衝突試験の場合、高強度鋼板を用いたＢピラーリンフォースは、Ｂピラーのフランジのスポット溶接部のＨＡＺ最軟化部にひずみが集中して破断起点となってＢピラーが衝突中に破断し、キャビン内へのＢピラーの侵入量が大きくなり、目標とする衝突性能を得られなくなることがある。また、Ｅｕｒｏ ＮＣＡＰのポール側突試験の場合、ルーフレールのフランジのスポット溶接部のＨＡＺ最軟化部にひずみが集中して破断起点となってルーフレールが破断してしまうことにより目標とする衝突性能を得られなくなることがある。 For example, a tubular structural member of an automobile body having a closed cross section, such as an A pillar, a B pillar, a roof rail, and a side sill and having a flange that is spot welded to form the cross section, is torn at the time of a car collision. Therefore, it is required to effectively absorb impact energy and protect passengers in the cabin by plastic deformation. However, in severe collision mode, for example, in the case of the American Road Safety Insurance Association (IIHS) SUV side collision test, B pillar reinforcement using high strength steel plate is the softest HAZ of the spot welds on the flange of the B pillar. In some cases, strain concentrates on the part and becomes a starting point of breakage, and the B-pillar breaks during the collision, and the amount of the B-pillar entering the cabin increases, and the target collision performance may not be obtained. Also, in the case of Euro NCAP pole side collision test, the target collision performance is obtained by the fact that strain concentrates on the HAZ softened part of the spot welded part of the flange of the roof rail and the roof rail breaks as a starting point of breakage. It may not be possible.
このため、これら１１８０ＭＰａ以上の高強度鋼板の自動車車体への適用では、自動車用構造部材におけるフランジに形成されたスポット溶接部のＨＡＺ最軟化部が衝突により破断起点とならない必要がある。 For this reason, in the application of these high-strength steel plates of 1180 MPa or more to the automobile body, the HAZ softest part of the spot weld formed on the flange of the automobile structural member needs not to be the starting point of breakage due to the collision.
非特許文献１には、ホットスタンプ成形されるルーフレールにおける衝突による破断の危険がある部分を、ホットスタンプ成形時に行う熱処理によって母材の強度を低下することによって、スポット溶接を行われてもＨＡＺ軟化を生じず、ＨＡＺ軟化部を起点とする自動車用構造部材の破断を防止する方法が開示されている。 Non-Patent Document 1 describes that HAZ softening is possible even when spot welding is performed by reducing the strength of a base material by heat treatment performed at the time of hot stamping at a portion of a roof rail that is hot stamped at risk of fracture. There is disclosed a method for preventing breakage of a structural member for an automobile starting from a HAZ softened portion.
非特許文献２には、ホットスタンプ成形品であるＢピラーのフランジ部を高周波加熱による焼戻しによって母材の強度を低下させ、スポット溶接を行われてもＨＡＺ軟化が生じず、ＨＡＺ軟化部を起点とする自動車用構造部材の破断を防止する方法が開示されている。 Non-Patent Document 2 describes that the strength of the base metal is reduced by tempering the B pillar, which is a hot stamped product, by high-frequency heating, and HAZ softening does not occur even if spot welding is performed. A method for preventing breakage of a structural member for an automobile is disclosed.
非特許文献１により開示されるようにルーフレールからＡピラーまで一体化された部品でルーフレールの部位を広い範囲で強度を調整する方法では、ルーフレールの比較的広い範囲に低強度部が不可避的に形成されることになり、高い強度が得られるというホットスタンプ成形部品のメリットを充分に享受することができず、軽量化の効果も限定的なものとなる。加えて、この方法では、焼入れ領域と未焼き入れ領域との間に不可避的に形成される比較的広い遷移領域において、強度特性がばらつき易く、部品の衝突性能にばらつきを生じる恐れがある。さらに、スポット溶接部を含む領域が軟化するため、スポット溶接継手の引張せん断強さが低下するおそれもある。 As disclosed in Non-Patent Document 1, in the method of adjusting the strength of the roof rail part over a wide range with the parts integrated from the roof rail to the A pillar, a low strength part is inevitably formed in a relatively wide range of the roof rail. As a result, the advantage of the hot stamped part that high strength can be obtained cannot be fully enjoyed, and the effect of weight reduction is also limited. In addition, in this method, strength characteristics are likely to vary in a relatively wide transition region inevitably formed between the quenching region and the unquenched region, and there is a risk of variation in the collision performance of components. Furthermore, since the area including the spot welded portion is softened, the tensile shear strength of the spot welded joint may be reduced.
非特許文献２により開示されるように、ホットスタンプ成形後にＢピラーのフランジを広範囲にわたり高周波加熱により焼き戻し軟化させる方法は、広範囲な焼き戻しにより発生する熱ひずみによってＢピラーが変形し、Ｂピラーの寸法精度が低下する恐れがある。Ｂピラーのみならず、Ａピラー，ルーフレールといったドアー開口部周りに配置される自動車用構造部材には、車体の建て付け精度を確保するために特に高い寸法精度が要求され、例えばドアーパネルとの間の隙間（パーティング）がドアーパネルの全周において均一になることが要求される。このため、ドアー開口部周りに配置される自動車用構造部材の寸法精度の低下は、自動車の外観品質を著しく損なう。また、フランジを広範囲に焼き戻すことにより、自動車用構造部材の強度が低下し、ホットスタンプ材の高強度な特性を享受できなくなる。さらに、スポット溶接部を含む領域が軟化するため、スポット溶接継手の引張せん断強さが低下するおそれもある。 As disclosed in Non-Patent Document 2, the method of softening the B pillar flange by high-frequency heating after hot stamping by high-frequency heating is that the B pillar is deformed by the thermal strain generated by the wide range of tempering. There is a risk that the dimensional accuracy of the will decrease. Not only the B pillar but also the structural members for automobiles arranged around the door opening such as the A pillar and the roof rail are required to have a particularly high dimensional accuracy in order to ensure the accuracy of building the vehicle body. The gap (parting) is required to be uniform over the entire periphery of the door panel. For this reason, the reduction in the dimensional accuracy of the structural member for automobiles arranged around the door opening part significantly impairs the appearance quality of the automobile. Further, by tempering the flange over a wide range, the strength of the structural member for automobile is lowered, and the high strength characteristics of the hot stamp material cannot be enjoyed. Furthermore, since the area including the spot welded portion is softened, the tensile shear strength of the spot welded joint may be reduced.
また、Ｂピラーなどの自動車用構造部材の構造の設計段階において、Ｂピラーのフランジにおけるスポット溶接部のＨＡＺ最軟化部が衝突時に破断するひずみに達することがないように、自動車用構造部材へのレインフォースメントの追加や、自動車用構造部材の板厚の増加などを行うことも考えられる。しかしながら、この方法では、部品点数や板厚の増加による自動車車体のコスト上昇や自動車車体の重量増加が避けられない。 In addition, in the design stage of the structure of an automotive structural member such as a B-pillar, the structural member for an automotive structural member may be prevented so that the HAZ softened portion of the spot welded portion of the flange of the B-pillar does not reach a strain that breaks at the time of collision. It is also possible to add reinforcement or increase the thickness of structural members for automobiles. However, this method inevitably increases the cost of the automobile body and increases the weight of the automobile body due to an increase in the number of parts and the plate thickness.
本発明は、従来の技術が有するこのような課題に鑑みてなされたものであり、引張強度が１１８０ＭＰａ以上の高強度鋼板またはその成形品に溶接（代表的にはスポット溶接）を行った場合でも、衝突時に溶接部のＨＡＺ最軟化部が起点となって低歪みで破断することを防止できる高強度鋼板の重ね溶接部材およびその製造方法を提供することを目的とする。 The present invention has been made in view of such problems of the prior art, and even when welding (typically spot welding) is performed on a high-strength steel sheet having a tensile strength of 1180 MPa or more or a molded product thereof. An object of the present invention is to provide a lap-welded member of a high-strength steel sheet that can be prevented from breaking at low strain starting from the HAZ softened part of the welded part at the time of collision, and a method for producing the same.
本発明は以下に列記の通りである。
（１）少なくとも、引張強度が１１８０ＭＰａ以上の鋼板またはその成形体である第１の構成部材と、他の鋼板またはその成形体であって第１の構成部材に重ねられて溶接された第２の構成部材とを備える重ね溶接部材であって、
重ね溶接部材は、溶接により形成された溶接金属と、重ね溶接部材の長手方向に溶接金属に隣接して少なくとも第１の構成部材側に設けられた長穴とを有し、
長穴は、重ね溶接部材の長手方向への長さがこの長手方向と直交する方向への長さよりも長い形状を有するとともに長手方向の一部に平行部を有し、溶接金属の周囲に形成されているＨＡＺ最軟化部にかからないように設けられていること
を特徴とする重ね溶接部材。本明細書では第１の重ね溶接部材ともいう。
The present invention is listed below.
(1) At least a first structural member which is a steel plate having a tensile strength of 1180 MPa or more or a molded body thereof, and another steel plate or a molded body thereof which is overlapped and welded to the first structural member. A lap weld member comprising component members,
The lap weld member has a weld metal formed by welding, and an elongated hole provided on the first component member side at least in the longitudinal direction of the lap weld member adjacent to the weld metal,
The long hole has a shape in which the length in the longitudinal direction of the lap weld member is longer than the length in the direction orthogonal to the longitudinal direction, and has a parallel portion in a part of the longitudinal direction, and is formed around the weld metal. A lap weld member characterized in that the lap weld member is provided so as not to be applied to the HAZ softened portion. In this specification, it is also referred to as a first lap weld member.
（２）少なくとも、引張強度が１１８０ＭＰａ以上の鋼板またはその成形体である第１の構成部材と、他の鋼板またはその成形体であって第１の構成部材に重ねられて溶接された第２の構成部材とを備える重ね溶接部材であって、
重ね溶接部材は、溶接により重ね溶接部材の長手方向に複数形成された溶接金属と、複数の溶接金属のうち少なくとも一対の隣接する２つの溶接金属の間で少なくとも第１の構成部材側に設けられた長穴とを有し、
長穴は、重ね溶接部材の長手方向への長さがこの長手方向と直交する方向への長さよりも長い形状を有するとともに長手方向の一部に平行部を有し、２つの溶接金属それぞれの周囲に形成されているＨＡＺ最軟化部にかからないように設けられていること
を特徴とする重ね溶接部材。本明細書では第２の重ね溶接部材ともいう。
(2) At least a first structural member that is a steel plate having a tensile strength of 1180 MPa or more or a molded body thereof, and another steel plate or a molded body that is overlapped and welded to the first structural member. A lap weld member comprising component members,
The lap weld member is provided at least on the first component side between a plurality of weld metals formed in the longitudinal direction of the lap weld member by welding and at least a pair of two adjacent weld metals among the plurality of weld metals. A long hole,
The long hole has a shape in which the length in the longitudinal direction of the lap weld member is longer than the length in the direction orthogonal to the longitudinal direction, and has a parallel portion in a part of the longitudinal direction . A lap weld member, characterized in that the lap weld member is provided so as not to be applied to a HAZ softened portion formed in the periphery. In this specification, it is also referred to as a second lap weld member.
（３）少なくとも、引張強度が１１８０ＭＰａ以上の鋼板またはその成形体である第１の構成部材と、他の鋼板またはその成形体であって第１の構成部材に重ねられて溶接された第２の構成部材とを備える重ね溶接部材であって、
重ね溶接部材は、溶接により形成された１つ以上の溶接金属と、溶接金属のうち少なくとも１つの溶接金属において、重ね溶接部材の長手方向の両隣りに隣接してこれを挟むように第１の構成部材側に設けられた２つの長穴とを有し、
長穴は、重ね溶接部材の長手方向への長さがこの長手方向と直交する方向への長さよりも長い形状を有するとともに長手方向の一部に平行部を有し、溶接金属の周囲に形成されているＨＡＺ最軟化部にかからないように設けられていること
を特徴とする重ね溶接部材。本明細書では第３の重ね溶接部材ともいう。
(3) At least a first structural member which is a steel plate having a tensile strength of 1180 MPa or more or a molded body thereof, and another steel plate or a molded body thereof which is overlapped and welded to the first structural member. A lap weld member comprising component members,
The lap weld member includes a first weld metal formed by welding and at least one of the weld metals so as to sandwich the lap weld member adjacent to both sides in the longitudinal direction of the lap weld member. Two elongated holes provided on the component side,
The long hole has a shape in which the length in the longitudinal direction of the lap weld member is longer than the length in the direction orthogonal to the longitudinal direction, and has a parallel portion in a part of the longitudinal direction, and is formed around the weld metal. A lap weld member characterized in that the lap weld member is provided so as not to be applied to the HAZ softened portion. In this specification, it is also referred to as a third lap weld member.
（４）第１の構成部材または第２の構成部材と重ね合わされてスポット溶接された鋼板またはその成形体である第３の構成部材を備える（１）項から（３）項までのいずれか１項に記載された重ね溶接部材。 (4) Any one of the items (1) to (3) provided with a third component member that is a steel plate or a formed body thereof that is spot-welded and overlapped with the first component member or the second component member. The lap weld member described in the item.
（５）長穴はナゲットの端から長手方向へ２．０ｍｍ以上離れて形成され、長手方向への長穴の平行部の長さが５ｍｍ以上５０ｍｍ以下であるとともに、長手方向と直交する方向への長穴の長さは３ｍｍ以上１５√ｔ（ｍｍ）以下である（１）項から（５）項までのいずれか１項に記載された重ね溶接部材。ただし、ｔは第１の構成部材の板厚（ｍｍ）である。 (5) The long hole is formed 2.0 mm or more away from the end of the nugget in the longitudinal direction, and the length of the parallel part of the long hole in the longitudinal direction is 5 mm or more and 50 mm or less, and in the direction orthogonal to the longitudinal direction. The lap-welded member according to any one of items (1) to (5), wherein the length of the elongated hole is 3 mm or more and 15√t (mm) or less. Here, t is the plate thickness (mm) of the first component member.
（６）長穴はレーザビームによる穴あけもしくは５００℃以上の温度での金型での打ち抜きにより形成される（１）項から（５）項までのいずれか１項に記載された重ね溶接部材。 (6) The lap weld member described in any one of items (1) to (5), wherein the elongated hole is formed by drilling with a laser beam or punching with a mold at a temperature of 500 ° C. or higher.
（７）（１）項から（６）項までのいずれか１項に記載された重ね溶接部材を構造部材として備えることを特徴とする自動車。 (7) An automobile comprising the lap weld member described in any one of items (1) to (6) as a structural member.
（８）少なくとも、引張強度が１１８０ＭＰａ以上の鋼板またはその成形体である第１の構成部材と他の鋼板またはその成形体である第２の構成部材とを重ね合わせて溶接する重ね溶接部材の製造方法であって、
第１の構成部材に部分的に少なくとも１つの、前記重ね溶接部材長手方向への長さが該長手方向と直交する方向への長さよりも長い形状を有するとともに長手方向の一部に平行部を有する長穴を設ける第１の工程と、
長穴を形成された第１の構成部材と第２の構成部材とを重ね合わせ、重ね溶接部材の長手方向に少なくとも長穴に隣接する部位で溶接し、溶接により形成される溶接金属の周囲のＨＡＺ最軟化部が長穴にかからないようにナゲットを形成する第２の工程とを備えること
を特徴とする重ね溶接部材の製造方法。
(8) Manufacture of a lap-welded member that overlaps and welds at least a first structural member that is a steel plate having a tensile strength of 1180 MPa or more or a molded body thereof and another steel plate or a second structural member that is a molded body thereof. A method,
At least one of the first component members has a shape in which the length in the longitudinal direction of the lap weld member is longer than the length in the direction perpendicular to the longitudinal direction, and a parallel portion is partially formed in the longitudinal direction. A first step of providing a long hole having ;
The first component member and the second component member formed with a long hole are overlapped, welded at least at a site adjacent to the long hole in the longitudinal direction of the lap weld member, and around the weld metal formed by welding. And a second step of forming a nugget so that the HAZ most softened portion does not cover the elongated hole.
（９）第２の工程において、第１の構成部材と、第２の構成部材と、これらとは他の鋼板又はその成形体である第３の構成部材とを重ね合わせてスポット溶接する（８）項に記載された重ね溶接部材の製造方法。 (9) In the second step, the first constituent member, the second constituent member, and the third constituent member that is another steel plate or a molded body thereof are overlapped and spot-welded (8 The manufacturing method of the lap-welded member described in the item).
（１０）長穴は溶接金属の端から長手方向へ２．０ｍｍ以上離れて形成され、長手方向への長穴の平行部の長さが５ｍｍ以上５０ｍｍ以下であるとともに、長手方向と直交する方向への長穴の長さは３ｍｍ以上１５√ｔ（ｍｍ）以下である（８）項または（９）項に記載された重ね溶接部材の製造方法。ただし、ｔは第１の構成部材の板厚（ｍｍ）である。 (10) The elongated hole is formed at a distance of 2.0 mm or more from the end of the weld metal in the longitudinal direction, and the length of the parallel portion of the elongated hole in the longitudinal direction is 5 mm or more and 50 mm or less, and the direction orthogonal to the longitudinal direction The method for producing a lap weld member described in the item (8) or (9), wherein the length of the long hole is 3 mm or more and 15√t (mm) or less. Here, t is the plate thickness (mm) of the first component member.
（１１）長穴をレーザビームによる穴あけもしくは５００℃以上の温度での金型での打ち抜きにより設ける（８）項から（１０）項までのいずれか１項に記載された重ね溶接部材の製造方法。 (11) The method for manufacturing a lap weld member according to any one of items (8) to (10), wherein the long hole is provided by drilling with a laser beam or punching with a die at a temperature of 500 ° C. or higher. .
本発明における「長穴」とは、部材の長手方向への長さがそれと直交する方向への長さよりも長い形状を有するとともに長手方向の一部に平行部を有する穴を意味する。 The “long hole” in the present invention means a hole having a shape in which the length in the longitudinal direction of the member is longer than the length in the direction perpendicular to the member and having a parallel portion in a part of the longitudinal direction.
本発明により、引張強度が１１８０ＭＰａ以上の高強度鋼板またはその成形品の組立てに溶接（代表的にはスポット溶接）を用いた場合でも、衝突時に溶接部のＨＡＺ最軟化部が低歪みで破断することを抑制できるようになる。これにより、例えば衝突時の乗員保護性能に優れ、高強度で形状精度の高い自動車用構造部材を提供できるようになる。 According to the present invention, even when welding (typically spot welding) is used for assembling a high-strength steel sheet having a tensile strength of 1180 MPa or more or a molded product thereof, the HAZ softest part of the welded part breaks with low strain at the time of collision. Can be suppressed. As a result, for example, it is possible to provide an automobile structural member that has excellent occupant protection performance at the time of a collision, high strength, and high shape accuracy.
本発明を実施するための形態を、添付図面を参照しながら説明する。なお、以降の説明では、溶接がスポット溶接である場合を例にとる。 A mode for carrying out the present invention will be described with reference to the accompanying drawings. In the following description, the case where welding is spot welding is taken as an example.
本発明は、引張強度が１１８０ＭＰａ以上の高強度鋼板を少なくとも１枚含む２枚以上の鋼板の重ね合わせ部を溶接する高強度鋼板の重ね溶接部材およびその製造方法に関するので、これらを順次説明する。
１．重ね溶接部材
本発明に係る重ね溶接部材１は、以下に説明する第１の重ね溶接部材、第２の重ね溶接部材または第３の重ね溶接部材として把握されるので、これらを、図１（ａ）、図１（ｂ）に示されるＢピラーの例を参照しながら、順次説明する。
The present invention relates to a lap weld member of a high-strength steel plate that welds an overlap portion of two or more steel plates including at least one high-strength steel plate having a tensile strength of 1180 MPa or more, and a manufacturing method thereof.
1. Lap Welding Member Since the lap welding member 1 according to the present invention is grasped as a first lap welding member, a second lap welding member, or a third lap welding member described below, these are shown in FIG. ) And will be described sequentially with reference to the example of the B pillar shown in FIG.
図１（ａ），図１（ｂ）は、Ｂピラーに本発明に係る第１〜３の重ね溶接部材を適用した状況を示し、図１（ａ）はＢピラーをサイドパネルアウタ側から透視したＢピラーリンフォースの斜視図であり、図１（ｂ）はＢピラーのＡ−Ａ断面図である。 FIGS. 1A and 1B show a state in which the first to third lap weld members according to the present invention are applied to a B pillar, and FIG. 1A is a perspective view of the B pillar from the side panel outer side. FIG. 1B is a cross-sectional view taken along line AA of the B pillar.
［第１の重ね溶接部材］
第１の重ね溶接部材は、少なくとも，第１の構成部材１と第２の構成部材７とを備える。第１の重ね溶接部材を構成する鋼板の重ね枚数は２枚もしくは３枚である。３枚重ねの場合は、第１の構成部材１および第２の構成部材７に加え、さらにこれらに重ねあわされて溶接される第３の構成部材１１を備える。
[First lap welding member]
The first lap weld member includes at least a first component member 1 and a second component member 7. The number of the steel plates constituting the first lap weld member is two or three. In the case of stacking three sheets, in addition to the first component member 1 and the second component member 7, a third component member 11 that is overlapped and welded thereto is provided.
第１の構成部材１は、引張強度が１１８０ＭＰａ以上の鋼板またはその成形体（以下、成形体の場合も含めて、鋼板と称する。）である。第２の構成部材７および第３の構成部材１１は、それぞれ第１の構成部材１とは別の、他の鋼板である。２枚重ね構造であれば、第２の構成部材７と第１の構成部材１とが重ねあわされてスポット溶接される。図１のように３枚重ね構造であれば、第２の構成部材７および第３の構成部材１１は、第１の構成部材１に重ねられてスポット溶接される。 The first constituent member 1 is a steel plate having a tensile strength of 1180 MPa or more or a molded body thereof (hereinafter referred to as a steel plate including a molded body). The second constituent member 7 and the third constituent member 11 are other steel plates different from the first constituent member 1. In the case of the two-layer structure, the second component member 7 and the first component member 1 are overlapped and spot welded. In the case of a three-layer structure as shown in FIG. 1, the second component member 7 and the third component member 11 are overlapped with the first component member 1 and spot welded.
このように、第１の重ね溶接部材は、第１の構成部材１および第２の構成部材７が（３枚重ね構造の場合はさらに第３の構造部材１１が）部分的に重ね合わされ、重ね合わせ部がスポット溶接されることにより、組み立てられた構造を有している。 In this way, the first lap weld member includes the first component member 1 and the second component member 7 partially overlapped (in the case of the three-layer structure, the third structure member 11). The mating portion is spot welded to have an assembled structure.
第１の重ね溶接部材において、第１の構成部材１は、スポット溶接により形成されたナゲット（溶接金属）２と長穴３とを有する。長穴３は、第１の重ね溶接部材の長手方向にナゲット２に隣接して少なくとも第１の構成部材１側に設けられる。長穴３は、ナゲット２の周囲に形成されているＨＡＺ最軟化部にかからないように設けられる。 In the first lap weld member, the first component 1 has a nugget (welded metal) 2 and a long hole 3 formed by spot welding. The long hole 3 is provided at least on the first component 1 side adjacent to the nugget 2 in the longitudinal direction of the first lap weld member. The long hole 3 is provided so as not to be applied to the HAZ most softened portion formed around the nugget 2.
第１の構成部材１を構成する鋼板は、連続焼鈍設備でマルテンサイトを含む焼入れ組織とした高張力鋼板や、ホットスタンプ用の鋼板をオーステナイト温度以上に加熱し、水冷金型で成形しながら焼入れることにより強度を高めたホットスタンプ鋼板が例示される。 The steel plate constituting the first component 1 is a high-strength steel plate having a quenching structure containing martensite in a continuous annealing facility or a hot stamping steel plate heated to an austenite temperature or higher and fired while being formed in a water-cooled mold. The hot stamped steel plate which raised the intensity | strength by putting is illustrated.
スポット溶接部２の破断は、部材の強度を主として担う第１の構成部材１がマルテンサイト組織の割合が多い引張強度が高い鋼板であるほど発生し易い傾向にある。したがって、第１の構成部材１がたとえばホットスタンプなどにより１５００ＭＰａ級以上の引張強度を有する場合に、本発明は特に大きな効果を発揮する。第１の構成部材１を構成する鋼板の引張強度の上限には特に制限はないが、２０００ＭＰａとすることが望ましい。 The fracture of the spot welded portion 2 tends to occur more easily as the first structural member 1 mainly responsible for the strength of the member is a steel plate having a higher martensite structure and a higher tensile strength. Therefore, the present invention exhibits a particularly great effect when the first component 1 has a tensile strength of 1500 MPa class or more by, for example, hot stamping. Although there is no restriction | limiting in particular in the upper limit of the tensile strength of the steel plate which comprises the 1st structural member 1, It is desirable to set it as 2000 MPa.
第１の構成部材１，第２の構成部材７および第３の構成部材１１を構成する鋼板の板厚の範囲も、通常の自動車強度部材用途に使用される、０．６ｍｍ〜２．６ｍｍ程度では十分適用可能である。 The thickness range of the steel plates constituting the first component member 1, the second component member 7 and the third component member 11 is also about 0.6 mm to 2.6 mm, which is used for ordinary automotive strength member applications. Is sufficiently applicable.
例えば、本発明をＢピラーに適用する場合は、サイドパネルアウタ（第３の構成部材１１）として板厚０．７ｍｍの２７０ＭＰａ級合金化溶融亜鉛めっき鋼板と、リンフォース（第１の構成部材１）として板厚１．８ｍｍの１５００ＭＰａ級ホットスタンプ鋼板もしくは板厚１．６ｍｍの１８００ＭＰａ級ホットスタンプ鋼板と、インナ（第２の構成部材７）として板厚１．２ｍｍの４４０ＭＰａ級冷延鋼板との３枚重ね構造であることが例示される。 For example, when the present invention is applied to a B-pillar, a 270 MPa class galvannealed steel sheet having a thickness of 0.7 mm as a side panel outer (third constituent member 11) and a reinforcement (first constituent member 1). ) As a 1500 MPa class hot stamped steel sheet having a thickness of 1.8 mm or a 1800 MPa class hot stamped steel sheet having a thickness of 1.6 mm, and a 440 MPa class cold rolled steel sheet having a thickness of 1.2 mm as the inner (second component 7). The three-layer structure is exemplified.
また、本発明をルーフレールに適用する場合は、サイドパネルアウタとして板厚０．７ｍｍの２７０ＭＰａ級合金化溶融亜鉛めっき鋼板と、リンフォースとして板厚１．２ｍｍの１５００ＭＰａ級ホットスタンプ鋼板と、インナとして板厚１．４ｍｍの５９０ＭＰａ級冷延鋼板との３枚重ね構造であることが例示される。 When the present invention is applied to a roof rail, a 270 MPa class galvannealed steel plate having a thickness of 0.7 mm as a side panel outer, a 1500 MPa class hot stamped steel plate having a thickness of 1.2 mm as a reinforcement, and an inner A three-ply structure with a 590 MPa grade cold-rolled steel sheet having a thickness of 1.4 mm is exemplified.
本発明をバンパーリンフォースに適用する場合は、リンフォースアウタ（第１の構成部材）として板厚１．４ｍｍの１８００ＭＰａ級ホットスタンプ鋼板と、リンフォースインナ（第２の構成部材）として板厚１．４ｍｍの５９０ＭＰａ級冷延鋼板との２枚重ね構造であることが例示される。 When the present invention is applied to a bumper reinforcement, a 1800 MPa class hot stamped steel plate having a thickness of 1.4 mm as a reinforcement outer (first component), and a plate thickness of 1 as a reinforcement inner (second component). It is exemplified by a two-ply structure with a 4 mm 590 MPa grade cold rolled steel sheet.
これらの例では、第１の構成部材１のみが１１８０ＭＰａ級以上の高強度鋼板であったが、第２の構成部材７または第３の構成部材１１が１１８０ＭＰａ級以上の高強度鋼板であってもよい。重ね合わされる第２の構成部材７が１１８０ＭＰａ級以上の高強度鋼板の場合、衝突時に重ね合わされる第２の構成部材７のスポット溶接部のＨＡＺ最軟化部での破断が予想されるケースでは、第２の構成部材７についても部分的に長穴３を形成すればよい。逆に衝突時に第２の構成部材７のスポット溶接のＨＡＺ最軟化部での破断が発生しないと予想されるケースでは、第２の構成部材７については長穴３を形成する必要はない。 In these examples, only the first component member 1 was a high-strength steel plate of 1180 MPa class or higher, but even if the second component member 7 or the third component member 11 is a high-strength steel plate of 1180 MPa class or higher. Good. In the case where the second constituent member 7 to be superposed is a high-strength steel plate of 1180 MPa class or more, in the case where a fracture at the HAZ softened portion of the spot welded portion of the second constituent member 7 superposed at the time of collision is expected, What is necessary is just to form the long hole 3 partially also about the 2nd structural member 7. FIG. On the other hand, in the case where it is predicted that no fracture will occur at the HAZ softened portion of the spot welding of the second component member 7 at the time of collision, it is not necessary to form the elongated hole 3 for the second component member 7.
第１の構成部材１の鋼板の表面は、非めっきでもよいし、めっきがされていてもよい。用いられるめっき鋼板としては、電気亜鉛めっき鋼板、電気亜鉛系合金めっき鋼板（たとえばＺｎ−Ｎｉ合金電気めっき鋼板）、溶融亜鉛めっき鋼板、合金化溶融亜鉛めっき鋼板、溶融アルミニウムめっき鋼板、溶融亜鉛−アルミニウム合金めっき鋼板などが例示される。またこれらがホットスタンプされた鋼板であってもよい。 The surface of the steel plate of the first component 1 may be non-plated or plated. Examples of the plated steel sheet used include an electrogalvanized steel sheet, an electrogalvanized alloy-plated steel sheet (for example, a Zn-Ni alloy electroplated steel sheet), a hot-dip galvanized steel sheet, an alloyed hot-dip galvanized steel sheet, a hot-dip aluminum-plated steel sheet, and hot-dip zinc-aluminum. Examples include alloy-plated steel sheets. Further, these may be hot stamped steel plates.
スポット溶接により第１の構成部材１と第２の構成部材７の界面に形成されるナゲット２のナゲット径は、４√ｔ以上７√ｔ以下（ｔ：重ね面の薄い側の板厚（ｍｍ））であることが望ましい。３枚重ね構造であれば、第１の構成部材１と第３の構成部材１１の界面においても同様である。 The nugget diameter of the nugget 2 formed at the interface between the first component member 1 and the second component member 7 by spot welding is 4√t or more and 7√t or less (t: plate thickness on the thin side of the overlapping surface (mm )) Is desirable. The three-layer structure is the same at the interface between the first component member 1 and the third component member 11.
［第２の重ね溶接部材］
第２，３の重ね溶接部材の以降の説明では、上述した第１の重ね溶接部材と相違する部分を説明し、共通する部分については重複する説明を適宜省略する。
[Second lap welding member]
In the subsequent description of the second and third lap weld members, portions that are different from the first lap weld member described above will be described, and overlapping descriptions of the common portions will be omitted as appropriate.
第２の重ね溶接部材は、複数のナゲット２と長穴３とを有する。複数のナゲット２は、スポット溶接により重ね溶接部材の長手方向に複数並んでされる。スポット溶接のピッチ、すなわち隣接するナゲット２の間の距離は、例えば２０〜１００ｍｍ程度であるが、これに限定されるものではなく、製品の仕様に応じて適宜設定すればよい。 The second lap weld member has a plurality of nuggets 2 and long holes 3. A plurality of nuggets 2 are arranged in the longitudinal direction of the lap weld member by spot welding. The pitch of spot welding, that is, the distance between adjacent nuggets 2 is, for example, about 20 to 100 mm, but is not limited to this, and may be set as appropriate according to product specifications.
長穴３は、複数のナゲット２のうち少なくとも一対の隣接する２つのナゲット２，２の間で少なくとも第１の構成部材１側に設けられる。長穴３は、２つのナゲット２，２それぞれの周囲に形成されているＨＡＺ最軟化部にかからないように設けられる。 The long hole 3 is provided at least on the first component 1 side between at least a pair of two adjacent nuggets 2 among the plurality of nuggets 2. The long hole 3 is provided so as not to be applied to the HAZ most softened portion formed around each of the two nuggets 2 and 2.
［第３の重ね溶接部材］
第３の重ね溶接部材は、スポット溶接により形成された１つ以上のナゲット２と２つの長穴３，３とを有する。２つの長穴３は、ナゲット２のうち少なくとも１つのナゲット２において、重ね溶接部材の長手方向の両隣りに隣接してナゲット２を挟むように第１の構成部材１側にいずれも設けられる。２つの長穴３は、いずれも、ナゲット２の周囲に形成されているＨＡＺ最軟化部にかからないように設けられている。
[Third lap welding member]
The third lap weld member has one or more nuggets 2 and two elongated holes 3 formed by spot welding. The two long holes 3 are provided on the first component 1 side so as to sandwich the nugget 2 adjacent to both sides in the longitudinal direction of the lap weld member in at least one nugget 2 of the nuggets 2. Both of the two long holes 3 are provided so as not to reach the HAZ most softened portion formed around the nugget 2.
第１の重ね溶接部材〜第３の重ね溶接部材における長穴３は、スポット溶接部２の打点の間に配置された長穴３がナゲット２の端から２．０ｍｍ以上離れて形成されることが望ましい。長穴３がナゲット２に近過ぎると、溶接時に溶融金属が飛び出すおそれがあるとともに継手強度が低下するためである。 The elongated hole 3 in the first lap weld member to the third lap weld member is formed such that the elongated hole 3 disposed between the hit points of the spot welded portion 2 is separated from the end of the nugget 2 by 2.0 mm or more. Is desirable. This is because if the long hole 3 is too close to the nugget 2, the molten metal may jump out during welding and the joint strength decreases.
後述する図２（ａ）により示すように、第１の重ね溶接部材〜第３の重ね溶接部材の長手方向への長穴３の平行部の長さは５ｍｍ以上５０ｍｍ以下であるとともに、長手方向と直交する方向への長穴３の長さ（幅）は３ｍｍ以上１５√ｔ（ｍｍ）以下（ただしｔは第１の構成部材１の板厚（ｍｍ）である）であることが望ましい。長穴３の長さが５ｍｍ未満では、十分な歪み吸収領域とはいえず、５０ｍｍを越えると自動車用構造部品の性能を低下させるためである。また、長穴３の幅は、３ｍｍ未満であると十分な歪み吸収ができず、１５√ｔ（ｍｍ）を超えると、自動車用構造部品の強度の低下が大きくなるためである。 As shown in FIG. 2A to be described later, the length of the parallel portion of the long hole 3 in the longitudinal direction of the first lap weld member to the third lap weld member is 5 mm or more and 50 mm or less, and the longitudinal direction. It is desirable that the length (width) of the long hole 3 in the direction orthogonal to is 3 mm or more and 15√t (mm) or less (where t is the plate thickness (mm) of the first component 1). If the length of the long hole 3 is less than 5 mm, it cannot be said that the strain-absorbing region is sufficient, and if it exceeds 50 mm, the performance of the structural component for automobile is deteriorated. Moreover, if the width of the long hole 3 is less than 3 mm, sufficient strain absorption cannot be achieved, and if it exceeds 15√t (mm), the strength of the structural component for automobiles is greatly reduced.
フランジに長穴３を設ける場合、長穴３の長手方向と直交する長さ（幅）は、フランジの幅の５０％以下とすることが望ましい。 When the elongated hole 3 is provided in the flange, the length (width) orthogonal to the longitudinal direction of the elongated hole 3 is preferably 50% or less of the width of the flange.
また、長穴３の位置は、長穴３の端からフランジの端までの距離が３ｍｍ以上となるように、フランジの端から離すことが望ましく、より好適には５ｍｍ以上離れることが望ましい。フランジの端から長穴３までの距離が近過ぎると、衝突時のフランジの変形により長穴が早期に破断するおそれがあるためである。 Further, the position of the long hole 3 is preferably separated from the end of the flange so that the distance from the end of the long hole 3 to the end of the flange is 3 mm or more, more preferably 5 mm or more. This is because if the distance from the end of the flange to the long hole 3 is too short, the long hole may break early due to deformation of the flange at the time of collision.
さらに、第１の重ね溶接部材〜第３の重ね溶接部材における長穴３は、レーザビームによる穴あけもしくは５００℃以上の温度での金型での打ち抜きにより設けられることが、穴あけ端面での遅れ破壊によるマイクロクラックの発生を防止する観点から、望ましい。 Further, the long hole 3 in the first lap weld member to the third lap weld member may be provided by drilling with a laser beam or punching with a die at a temperature of 500 ° C. or higher, so that the delayed fracture at the drilling end surface. It is desirable from the viewpoint of preventing the occurrence of microcracks.
次に、具体的な態様例として、Ｂピラーおよびルーフレールでの適用例について、それぞれ図１（ａ）および（ｂ）、図２（ａ）および図２（ｂ）を参照してさらに説明する。 Next, as a specific example, application examples in the B pillar and the roof rail will be further described with reference to FIGS. 1A and 1B, FIG. 2A and FIG. 2B, respectively.
図１（ａ），図１（ｂ）は、Ｂピラーに本発明に係る第１〜３の重ね溶接部材を適用した状況を示す説明図であって、図１（ａ）はＢピラーをサイドパネルアウタ側から透視したＢピラーリンフォースの斜視図であり、図１（ｂ）はＢピラーのＡ−Ａ断面図である。 FIG. 1A and FIG. 1B are explanatory views showing a situation in which the first to third lap weld members according to the present invention are applied to a B pillar, and FIG. FIG. 1B is a perspective view of a B pillar reinforcement seen through from the panel outer side, and FIG. 1B is a cross-sectional view of the B pillar taken along line AA.
Ｂピラー０においては、第１の構成部材であるＢピラーリンフォース１と、第２の構成部材であるインナ材７と、第３の構成部材であるサイドパネルアウタ材１１とが重ね合わされて、フランジ部（Ｂピラーリンフォース１においてはフランジ１ａ）に断続的に複数のスポット溶接部２が形成されている。この例では、Ｂピラーリンフォース１の上部では、スポット溶接部２の間に長穴３が形成され、Ｂピラーリンフォース１の下部では、同様にスポット溶接部２の間に長穴３が形成され、Ｂピラーの高さ方向中間部では、スポット溶接部２の間には長穴３が形成されていない。 In the B pillar 0, the B pillar reinforcement 1 as the first component, the inner material 7 as the second component, and the side panel outer material 11 as the third component are overlapped, A plurality of spot welds 2 are intermittently formed on the flange (the flange 1a in the B pillar reinforcement 1). In this example, an elongated hole 3 is formed between the spot welds 2 at the upper part of the B pillar reinforcement 1, and an elongated hole 3 is similarly formed between the spot welds 2 at the lower part of the B pillar reinforcement 1. In addition, the elongated hole 3 is not formed between the spot welds 2 in the intermediate portion in the height direction of the B pillar.
上部の長穴３の形成は、衝突時にＢピラー０の上部でのスポット溶接部のＨＡＺ最軟化部での破断による折れを防止し、下部の長穴３の形成は、衝突での大変形領域でのスポット溶接のＨＡＺ最軟化部での破断を防止する。ＨＡＺ最軟化部が破断するひずみに達しない、Ｂピラーリンフォース１のフランジ１ａの高さ方向中央部には、長穴３を形成しない。このように、長穴３の形成は、衝突時のスポット溶接部２のＨＡＺ最軟化部を起点とする破断を防止するために、必要最小限であればよい。 The formation of the upper elongated hole 3 prevents breakage due to breakage at the HAZ softened portion of the spot welded portion at the upper part of the B pillar 0 at the time of collision, and the formation of the lower elongated hole 3 is a large deformation region due to the collision. To prevent breakage at the HAZ softest part of spot welding. The elongated hole 3 is not formed in the central portion in the height direction of the flange 1a of the B pillar reinforcement 1 that does not reach the strain at which the HAZ softest portion breaks. Thus, the formation of the long hole 3 may be the minimum necessary to prevent breakage starting from the HAZ most softened portion of the spot welded portion 2 at the time of collision.
このように、Ｂピラー０のフランジ部では、Ｂピラー０の高さ方向位置に応じて、一つのスポット溶接部２に隣接して一つの長穴３が形成され（第１の重ね溶接部材）、隣接する二つのスポット溶接部２の間に一つの長穴３が形成され（第２の重ね溶接部材）、さらに、一つのスポット溶接部２の両隣に隣接して二つの長穴３が形成されている（第３の重ね溶接部材）といえる。 As described above, in the flange portion of the B pillar 0, one long hole 3 is formed adjacent to one spot weld portion 2 in accordance with the height direction position of the B pillar 0 (first lap weld member). In addition, one long hole 3 is formed between two adjacent spot welds 2 (second lap weld member), and two long holes 3 are formed adjacent to both sides of one spot weld 2. (Third lap welding member).
なお、図１の例では、Ｂピラーリンフォース１の内側に第４の構成部材であるヒンジリンフォース１５（例えば９８０ＭＰａ級冷延鋼板）が重ねあわされて、互いの溝底部で２枚重ね溶接されている。 In the example of FIG. 1, a hinge reinforcement 15 (for example, a 980 MPa class cold-rolled steel plate) as a fourth constituent member is overlapped inside the B pillar reinforcement 1 and two sheets are welded at the bottom of each groove. Has been.
図２（ａ），図２（ｂ）は、ルーフレールに本発明に係る第１〜３の重ね溶接部材を適用した状況を示す説明図であって、図２（ａ）はルーフレールをルーフレールインナ側から透視したルーフレールアウタリンフォースの斜視図であり、図２（ｂ）はルーフレールのＢ−Ｂ断面図である。 2 (a) and 2 (b) are explanatory views showing a situation in which the first to third lap weld members according to the present invention are applied to the roof rail, and FIG. 2 (a) shows the roof rail on the roof rail inner side. FIG. 2 is a perspective view of the roof rail outer force seen through, and FIG. 2B is a cross-sectional view of the roof rail taken along line BB.
ルーフレール００においては、第３の構成部材であるサイドパネルアウタ５、第１の構成部材であるルーフレールアウタ４、および第２の構成部材であるルーフレールインナ１２が重ね合わされて、フランジ部（ルーフレールアウタ４では４ａ）に断続的に複数のスポット溶接部２が形成されている。ルーフレールアウタ４のスポット溶接部２の間に局所的な長穴３が形成されている。これにより、ルーフレールアウタ４の強度を極力下げることなく、スポット溶接のＨＡＺ最軟化部での破断を抑制することができる。なお、図２（ａ）における符号６はＡピラーを示す。 In the roof rail 00, the side panel outer 5 that is the third component, the roof rail outer 4 that is the first component, and the roof rail inner 12 that is the second component are overlapped to form a flange portion (the roof rail outer 4). Then, a plurality of spot welds 2 are formed intermittently in 4a). A local slot 3 is formed between the spot welds 2 of the roof rail outer 4. Thereby, the fracture | rupture in the HAZ softest part of spot welding can be suppressed, without reducing the intensity | strength of the roof rail outer 4 as much as possible. In addition, the code | symbol 6 in Fig.2 (a) shows A pillar.
このように、ルーフレール００のフランジ部では、ルーフレール００の長手位置に応じて、一つのスポット溶接部２に隣接して一つの長穴３が形成され（第１の重ね溶接部材）、隣接する二つのスポット溶接部２の間に一つの長穴３が形成され（第２の重ね溶接部材）、さらに、一つのスポット溶接部２の両隣に隣接して二つの長穴３が形成されている（第３の重ね溶接部材）といえる。 As described above, in the flange portion of the roof rail 00, one elongated hole 3 is formed adjacent to one spot welded portion 2 (first lap weld member) in accordance with the longitudinal position of the roof rail 00. One elongated hole 3 is formed between two spot welds 2 (second lap weld member), and two elongated holes 3 are formed adjacent to both sides of one spot weld 2 (see FIG. It can be said that this is a third lap weld member.
次に、本発明における長穴３の技術的意義を説明する。
図３（ａ）は、低強度鋼板の成形体である第２の構成部材７にスポット溶接により接合される第１の構成部材１のフランジ１ａの近傍の一例を模式的に示す説明図であり、図３（ｂ）は図３（ａ）中の測定位置Ｃ（第１の構成部材１における破線により示す板厚中央位置）における第１の構成部材１の硬さ分布の一例を示すグラフである。
Next, the technical significance of the long hole 3 in the present invention will be described.
Fig.3 (a) is explanatory drawing which shows typically an example of the vicinity of the flange 1a of the 1st structural member 1 joined to the 2nd structural member 7 which is a molded object of a low strength steel plate by spot welding. FIG. 3B is a graph showing an example of the hardness distribution of the first component member 1 at the measurement position C (plate thickness center position indicated by the broken line in the first component member 1) in FIG. is there.
図３（ａ）に示すように、１５００ＭＰａ級冷延鋼板の成形品（第１の構成部材）１が、フランジ１ａを介して、４４０ＭＰａ級鋼板の成形品７（第２の構成部材）と重ね合わされ、フランジ１ａの延設方向へ断続的にスポット溶接部２が形成され（図３では一つのスポット溶接部２を示す）、第１の構成部材１のフランジ１ａのスポット溶接部２に隣接して長穴３が形成されている。 As shown in FIG. 3 (a), a 1500 MPa-class cold-rolled steel sheet molded product (first constituent member) 1 is overlapped with a 440 MPa-class steel plate molded product 7 (second constituent member) via a flange 1a. The spot welded portion 2 is intermittently formed in the extending direction of the flange 1a (one spot welded portion 2 is shown in FIG. 3), and is adjacent to the spot welded portion 2 of the flange 1a of the first component 1 A long hole 3 is formed.
図３（ｂ）のグラフに示すように、スポット溶接部２の周囲には、硬さが３００Ｈｖ程度に低下するＨＡＺ最軟化部が形成されているが、長穴３が、ＨＡＺ最軟化部にかからないように設けられている。 As shown in the graph of FIG. 3 (b), the HAZ most softened portion whose hardness is reduced to about 300 Hv is formed around the spot welded portion 2, but the long hole 3 is formed in the HAZ most softened portion. It is provided so that it does not take.
図４（ａ）は、本発明の効果を示すグラフであり、図３に示すような１５００ＭＰａ級のホットスタンプ材に４４０ＭＰａ級冷延鋼板がスポット溶接された部材のフランジを模擬した引張試験片に引張荷重を与えた場合の応力−歪み線図であり、図４（ｂ）は、比較例の引張試験片を示す説明図であり、図４（ｃ）は本発明例の引張試験片（第３の重ね溶接部材）を示す説明図である。 FIG. 4A is a graph showing the effect of the present invention. In a tensile test piece simulating a flange of a member in which a 440 MPa class cold-rolled steel plate is spot welded to a 1500 MPa class hot stamp material as shown in FIG. 4 is a stress-strain diagram when a tensile load is applied, FIG. 4B is an explanatory view showing a tensile test piece of a comparative example, and FIG. FIG.
図４（ｃ）に示す引張試験片、すなわち１５００ＭＰａ級の鋼板（第１の構成部材）１が４４０ＭＰａ級の鋼板（第２の構成部材）７と重ね合わされスポット溶接部２が形成され、さらに非常に狭い範囲の長穴３（幅１０ｍｍ，長さ１５ｍｍ，平行部長さ１０ｍｍ）がスポット溶接部２を挟んで第１の構成部材１に設けられた引張試験片では、図４（ｂ）のような長穴３を設けない引張試験片と比較して、図４（ａ）に示すように、引張荷重に対して破断の発生する歪み量が格段に増加し、吸収エネルギーが大きくなっていた。これは、試験片（すなわち重ね構造部材）に引張荷重が負荷されたときに、長穴３の周辺にもひずみがかかり、スポット溶接のＨＡＺ最軟化部にのみ局所的にひずみが集中することが抑制されたため、スポット溶接部２においてＨＡＺ最軟化部が存在していても、図４（ａ）のグラフに示すように、重ね溶接部材が破断する変形量が向上したものである。このような機構により、ＨＡＺ最軟化部が起点となる少ない歪みでの破断が抑制される。 The tensile test piece shown in FIG. 4C, that is, a 1500 MPa class steel plate (first constituent member) 1 is overlapped with a 440 MPa class steel plate (second constituent member) 7 to form a spot welded portion 2, and further In a tensile test piece in which a long hole 3 (width 10 mm, length 15 mm, parallel portion length 10 mm) in a narrow range is provided in the first component 1 with the spot weld 2 interposed therebetween, as shown in FIG. Compared with a tensile test piece not provided with an elongated hole 3, as shown in FIG. 4 (a), the amount of strain at which breakage occurred with respect to the tensile load was significantly increased, and the absorbed energy was increased. This is because when a tensile load is applied to the test piece (that is, the laminated structure member), the periphery of the elongated hole 3 is also strained, and the strain is locally concentrated only in the HAZ softened portion of spot welding. Therefore, even if the HAZ most softened portion is present in the spot welded portion 2, as shown in the graph of FIG. 4A, the deformation amount at which the lap weld member breaks is improved. By such a mechanism, the fracture | rupture with few distortions which a HAZ softest part starts is suppressed.
また、高強度鋼板の断続的なスポット溶接部２の間の所定の範囲のみに長穴３を形成するため、従来のフランジ１ａを広範囲に焼き戻す手法や、重ね溶接部材の広い範囲に軟化領域を形成する手法に比べると、穴あけ時の熱歪みの影響が小さいため、部品の変形が極めて小さい。そのため、Ｂピラー，ルーフレール，Ａピラーなどの高い形状精度を要求される自動車用構造部材への適用に適する。加えて、長穴３がスポット溶接部２の間の局所的な部分であるため、重ね溶接部材の強度低下が小さく、ホットスタンプ材など高強度材の材料特性を十分に生かすことができる。 Further, in order to form the long hole 3 only in a predetermined range between the intermittent spot welds 2 of the high-strength steel plate, a conventional method of tempering the flange 1a in a wide range, a softening region in a wide range of the lap weld member Compared with the method of forming the metal, the deformation of the component is extremely small because the influence of thermal distortion during drilling is small. Therefore, it is suitable for application to automobile structural members that require high shape accuracy such as B pillars, roof rails, and A pillars. In addition, since the long hole 3 is a local portion between the spot welded portions 2, the strength reduction of the lap weld member is small, and the material characteristics of a high strength material such as a hot stamp material can be fully utilized.
このようにして、図１（ａ）〜図１（ｄ）に示すように、側面衝突でキャビン内の乗員を保護する重要部材であるＢピラー，ルーフレール，サイドシルなどの、キャビンを取り囲んで配置される自動車用構造部材に本発明を適用することにより、これらの自動車用構造部材のスポット溶接部のＨＡＺ最軟化部での破断を抑制でき、側面衝突時に対する安全性を高めることができる。さらに、パーリンフォース，ドアビーム，フロアメンバー，フロントサイドメンバー，リアサイドメンバーへも本発明を適用することにより、これらの部品の強度特性を高めることができる。 In this way, as shown in FIGS. 1 (a) to 1 (d), the B pillar, roof rail, side sill and the like, which are important members for protecting passengers in the cabin by side collision, are arranged so as to surround the cabin. By applying the present invention to structural members for automobiles, it is possible to suppress breakage at the HAZ most softened portion of the spot welded portion of these structural members for automobiles, and it is possible to improve safety against side collision. Furthermore, the strength characteristics of these parts can be enhanced by applying the present invention to the perlin force, door beam, floor member, front side member, and rear side member.
長穴３は、図５に示すように種々の形態をとりうる。図５（ａ）〜図５（ｆ）は、高強度鋼板である第１の構成部材１におけるスポット溶接部２と長穴３の関係を概念的に示す説明図である。 The long hole 3 can take various forms as shown in FIG. FIG. 5A to FIG. 5F are explanatory views conceptually showing the relationship between the spot welded portion 2 and the long hole 3 in the first component 1 which is a high-strength steel plate.
図５（ａ）は、第１の構成部材１のフランジ１ａのスポット溶接部２の間それぞれに、スポット溶接部２と一直線上に長穴３が２つ形成されたものである。 FIG. 5A shows a structure in which two elongated holes 3 are formed in a straight line with the spot welded portion 2 between the spot welded portions 2 of the flange 1 a of the first component 1.
図５（ｂ）は、第１の構成部材１のフランジ１ａのスポット溶接部２の間それぞれに、スポット溶接部２と一直線上に、端部にＲ部を有する長穴３が２つ形成されたものである。 FIG. 5B shows that two elongated holes 3 each having an R portion at the end are formed in a straight line with the spot welded portion 2 between the spot welded portions 2 of the flange 1a of the first component 1. It is a thing.
図５（ｃ）は、第１の構成部材１のフランジ１ａのスポット溶接部２の間で、スポット溶接部２よりも第１の構成部材１の端面１ｂ側に長穴３が形成されたものである。 FIG. 5 (c) shows a structure in which a long hole 3 is formed on the end surface 1 b side of the first component member 1 with respect to the spot welded portion 2 between the spot welded portions 2 of the flange 1 a of the first component member 1. It is.
図５（ｄ）は、第１の構成部材１のフランジ１ａのスポット溶接部２の間で、曲げＲ部１ｃ側に長穴３が形成されたものである
図５（ｅ）は、第１の構成部材１のフランジ１ａのスポット溶接部２の間に、２つの長穴３が並んで形成されたものである。
FIG. 5D shows an elongated hole 3 formed on the bending R portion 1 c side between the spot welded portions 2 of the flange 1 a of the first component 1. FIG. The two elongated holes 3 are formed side by side between the spot welds 2 of the flange 1a of the component 1 of FIG.
さらに、図５（ｆ）は、第１の構成部材１のフランジ１ａのスポット溶接部２の間に、長さが長い長穴３が一つ形成されたものである。
２．重ね溶接部材の製造方法
本発明において重ね溶接部材を製造するには、長穴を形成した後にスポット溶接する。以下、この重ね溶接部材の製造方法を説明する。
Further, FIG. 5 (f) shows that one long hole 3 having a long length is formed between the spot welds 2 of the flange 1 a of the first component 1.
2. Manufacturing Method of Lap Welding Member In order to manufacture a lap welding member in the present invention, spot welding is performed after forming a long hole. Hereinafter, the manufacturing method of this lap welding member is demonstrated.
なお、以下の説明は、主として２枚重ね構造についてのものであるが、３枚重ね構造でも同様である。また、図１に示すような、重ね溶接部材の長手方向に複数の溶接部および長穴が形成される部材を想定して説明する。 The following description is mainly about the two-layer structure, but the same applies to the three-layer structure. Further, description will be made assuming a member in which a plurality of welds and long holes are formed in the longitudinal direction of the lap weld member as shown in FIG.
第１の工程で引張強度が１１８０ＭＰａ以上の第１の構成部材１の母材に部分的に長穴３を形成し、他の鋼板（第２の構成部材）と重ね合わせ、第２の工程で長穴３の外側の母材部にて長穴３に隣接する部位にスポット溶接を行うことによりナゲット２を形成する。 In the first step, the elongated hole 3 is partially formed in the base material of the first constituent member 1 having a tensile strength of 1180 MPa or more and overlapped with another steel plate (second constituent member). In the second step The nugget 2 is formed by performing spot welding on a portion adjacent to the elongated hole 3 at the base material portion outside the elongated hole 3.
まず、第１の工程では、スポット溶接により断続的にナゲット２の形成が予定されている部分の間に、例えば略矩形状の長穴３を形成する。すなわち、スポット溶接前に、スポット溶接予定位置の間に部分的に長穴３を形成し、第２の工程でスポット溶接する。 First, in the first step, for example, a substantially rectangular long hole 3 is formed between portions where the nugget 2 is scheduled to be formed intermittently by spot welding. That is, before spot welding, the elongated holes 3 are partially formed between the spot welding scheduled positions, and spot welding is performed in the second step.
スポット溶接の溶接条件には特に制限はなく、少なくとも対象となる鋼板の重ね合わせ界面にナゲット径が４√ｔ以上７√ｔ以下（ｔ：重ね面の薄い側の板厚（ｍｍ））となるナゲット２が形成されるように適宜決定すればよい。例えば、単相交流スポット溶接機もしくはインバータ直流スポット溶接機を用い、溶接電極の先端直径を６〜８ｍｍの範囲とし、先端の曲率半径Ｒを例えば４０ｍｍとし、加圧力を２．５〜６．０ｋＮの範囲とし、溶接電流の電流値を７〜１１ｋＡの範囲とし、通電時間を１０／６０〜４０／６０秒の範囲とすればよい。スポット溶接条件は例示した条件に限定されるものではなく、鋼種や板厚などに応じて適宜調整すればよいことは言うまでもない。 There are no particular restrictions on the welding conditions for spot welding, and the nugget diameter is at least 4√t and not more than 7√t (t: plate thickness (mm) on the thin side of the overlapping surface) at least at the overlapping interface of the target steel plates. What is necessary is just to determine suitably so that the nugget 2 may be formed. For example, a single-phase AC spot welder or an inverter DC spot welder is used, the tip diameter of the welding electrode is in the range of 6 to 8 mm, the curvature radius R of the tip is, for example, 40 mm, and the applied pressure is 2.5 to 6.0 kN. The current value of the welding current may be in the range of 7 to 11 kA, and the energization time may be in the range of 10/60 to 40/60 seconds. It goes without saying that the spot welding conditions are not limited to the exemplified conditions, and may be adjusted as appropriate according to the steel type, plate thickness, and the like.
長穴３の形成方法は、レーザビームによる穴あけもしくは５００℃以上の温度での金型での打ち抜きが挙げられる。好適にはレーザビームによる穴あけである。レーザビームは、エネルギーが安定しているためである。レーザビームとしては、ディスクレーザ，ファイバーレーザ，ダイレクトダイオードレーザ，ＹＡＧレーザ，炭酸ガスレーザを用いることが例示される。穴あけ条件は、ビーム径：０．０５〜０．２ｍｍ，出力：０．５〜１０ｋＷ，溶接速度：０．５〜２０ｍ／ｍｉｎ，アシストガス：酸素，窒素，空気であることが例示される。 Examples of the method of forming the long hole 3 include drilling with a laser beam or punching with a mold at a temperature of 500 ° C. or higher. Drilling with a laser beam is preferred. This is because the energy of the laser beam is stable. Examples of the laser beam include disk laser, fiber laser, direct diode laser, YAG laser, and carbon dioxide laser. Examples of the drilling conditions include beam diameter: 0.05 to 0.2 mm, output: 0.5 to 10 kW, welding speed: 0.5 to 20 m / min, assist gas: oxygen, nitrogen, and air.
第２の工程では、第１の構成部材１は、第２の構成部材と重ね合わされ、スポット溶接によりナゲット２を形成することにより第２の構成部材と接合される。 In the second step, the first constituent member 1 is overlapped with the second constituent member and joined to the second constituent member by forming a nugget 2 by spot welding.
第２の構成部材が１１８０ＭＰａ級以上の高強度鋼板である場合など、衝突時に第２の構成部材のスポット溶接部のＨＡＺ最軟化部での破断が予想されるケースでは、第２の構成部材についても、前述の第１の工程での説明と同様に、予め部分的に長穴３を形成すればよい。 In the case where the second constituent member is a high strength steel plate of 1180 MPa class or higher, and the HAZ softened portion of the spot welded portion of the second constituent member is expected to break at the time of collision, the second constituent member In the same manner as described in the first step, the elongated hole 3 may be partially formed in advance.
以上の説明は、重ね枚数が２枚の場合を例にとったが、重ね枚数が３枚の場合、すなわち例えば図１に示すように、第２の構成部材７と第３の構成部材１１との間に第１の構成部材１を配置する構造の場合には、第２の工程でさらに第３の構成部材を重ね合わせ３枚重ねでスポット溶接を行うようにしてもよい。 In the above description, the case where the number of stacked sheets is two is taken as an example. However, when the number of stacked sheets is three, that is, as shown in FIG. 1, for example, the second component member 7 and the third component member 11 In the case of the structure in which the first constituent member 1 is arranged between the two, the third constituent member may be further overlapped in the second step, and spot welding may be performed by superimposing three sheets.
また、第１、２の構成部材１，７をいずれも引張強度が１１８０ＭＰａ以上の高強度鋼板により構成するとともに第３の構成部材１１を引張強度が例えば２７０〜９８０ＭＰａ級の鋼板により構成する場合には、第１の構成部材１または第２の構成部材７の一方または双方に長穴３を形成してから（長穴３は必要性に応じて一方または双方に形成するかを判断する）、第１の構成部材１と第２の構成部材７と第３の構成部材１１とを重ねてスポット溶接するようにしてもよい。 Further, when both the first and second constituent members 1 and 7 are made of a high strength steel plate having a tensile strength of 1180 MPa or more and the third constituent member 11 is made of a steel plate having a tensile strength of, for example, 270 to 980 MPa. After forming the long hole 3 in one or both of the first structural member 1 or the second structural member 7 (determining whether the long hole 3 is formed in one or both according to necessity), The first component member 1, the second component member 7, and the third component member 11 may be overlapped and spot welded.
以上説明した本発明に係る重ね溶接構造は、引張強度が１１８０ＭＰａ以上の高強度鋼板を含む自動車用構造部材への適用に適する。例えば、Ｂピラー，Ａピラー，ルーフレール，サイドシル，バンパーリンフォース，ドアビーム，フロアメンバー，フロントサイドメンバー，リアサイドメンバーなどへ適用可能である。 The lap welded structure according to the present invention described above is suitable for application to an automotive structural member including a high-strength steel plate having a tensile strength of 1180 MPa or more. For example, the present invention can be applied to B pillars, A pillars, roof rails, side sills, bumper reinforcements, door beams, floor members, front side members, rear side members, and the like.
以上の説明では、溶接がスポット溶接である場合を例にとったが、本発明はスポット溶接に限定されるものではなく、レーザ溶接やアーク溶接といったスポット溶接以外の他の溶接についても等しく適用される。 In the above description, the case where the welding is spot welding has been taken as an example, but the present invention is not limited to spot welding, and is equally applied to other welding other than spot welding such as laser welding and arc welding. The
図６（ａ）〜図９（ａ）は、いずれも、低強度鋼板の成形品である第２の構成部材７とともに重ね溶接部材を構成する、高強度鋼板（１５００ＭＰａ級ホットスタンプ鋼板）の成形品である第１の構成部材１における各種の溶接部２−１〜２〜４と長穴３の関係を概念的に示す説明図であり、図６（ｂ）〜図９（ｂ）は、それぞれ図６（ａ）〜図９（ａ）中の断面図における硬さ測定位置Ｃにおける第１の構成部材１の硬さの測定結果を示すグラフである。 6 (a) to 9 (a) are all formed of a high-strength steel plate (1500 MPa class hot stamped steel plate) that constitutes a lap weld member together with the second component member 7 that is a molded product of a low-strength steel plate. It is explanatory drawing which shows notionally the relationship between the various welding parts 2-1 to 2-4 and the long hole 3 in the 1st structural member 1 which is goods, FIG.6 (b)-FIG.9 (b) It is a graph which shows the measurement result of the hardness of the 1st structural member 1 in the hardness measurement position C in sectional drawing in Fig.6 (a)-FIG.9 (a), respectively.
図６（ａ）は、第１の構成部材１のフランジ１ａにＣ字状レーザ溶接部２−１を形成し、隣接するＣ字状レーザ溶接部２−１，２−１の間それぞれに、Ｃ字状レーザ溶接部２−１と一直線上に長穴３が２つ形成されたものである。 FIG. 6A shows that a C-shaped laser welded portion 2-1 is formed on the flange 1a of the first component 1, and between the adjacent C-shaped laser welded portions 2-1, 2-1 respectively. Two elongated holes 3 are formed in a straight line with the C-shaped laser welded part 2-1.
図７（ａ）は、第１の構成部材１のフランジ１ａにリング状レーザ溶接部２−２を形成し、隣接するリング状レーザ溶接部２−２，２−２の間それぞれに、リング状レーザ溶接部２−２と一直線上に長穴３が２つ形成されたものである。 FIG. 7A shows a ring-shaped laser welded portion 2-2 formed on the flange 1a of the first component 1, and a ring-like shape between the adjacent ring-shaped laser welded portions 2-2 and 2-2. Two elongated holes 3 are formed in a straight line with the laser welded portion 2-2.
図８（ａ）は、第１の構成部材１のフランジ１ａに円状レーザ溶接部２−３を形成し、隣接する円状レーザ溶接部２−３，２−３の間それぞれに、円状レーザ溶接部２−３と一直線上に長穴３が２つ形成されたものである。 FIG. 8A shows a circular laser welded portion 2-3 formed on the flange 1a of the first component 1, and a circular shape is formed between the adjacent circular laser welded portions 2-3 and 2-3. Two elongated holes 3 are formed in a straight line with the laser weld 2-3.
さらに、図９（ａ）は、第１の構成部材１のフランジ１ａに円状アーク溶接部２−４を形成し、隣接する円状アーク溶接部２−４，２−４の間それぞれに、円状アーク溶接部２−４と一直線上に長穴３が２つ形成されたものである。 Furthermore, Fig.9 (a) forms the circular arc welding part 2-4 in the flange 1a of the 1st component 1, and each between the adjacent circular arc welding parts 2-4 and 2-4, Two elongated holes 3 are formed in a straight line with the circular arc welded portion 2-4.
本発明を、実施例を参照しながら、より具体的に説明する。
供試材の化学成分を表１に示す。表１の単位は質量％であり、表１に示される以外の残部はＦｅおよび不順物である。
The present invention will be described more specifically with reference to examples.
Table 1 shows chemical components of the test materials. The units in Table 1 are mass%, and the balance other than those shown in Table 1 is Fe and irregular substances.
表１における供試材ＳＱ１５００は、非めっきの冷延鋼板をホットスタンプして得た引張強度１５００ＭＰａ級のホットスタンプ鋼板であり、供試材ＳＱＺ１５００は、合金化溶融亜鉛めっき鋼板をホットスタンプして得た引張強度１５００ＭＰａ級ホットスタンプ鋼板であり、供試材ＳＱ１８００は、非めっきの冷延鋼板をホットスタンプして得た引張強度１８００ＭＰａ級ホットスタンプ鋼板であり、供試材ＪＳＣ１２７０は、非めっきの引張強度１２７０ＭＰａ級の冷延鋼板である。また、表１における供試材ＪＳＣ４４０は、非めっきの４４０ＭＰａ級鋼板である。 The test material SQ1500 in Table 1 is a hot stamped steel plate with a tensile strength of 1500 MPa obtained by hot stamping a non-plated cold rolled steel plate, and the test material SQZ1500 is obtained by hot stamping an alloyed hot dip galvanized steel plate. The obtained tensile strength is a 1500 MPa class hot stamped steel plate, the test material SQ1800 is a hot stamped steel plate having a tensile strength of 1800 MPa obtained by hot stamping a non-plated cold-rolled steel plate, and the test material JSC1270 is a non-plated steel plate. It is a cold-rolled steel sheet having a tensile strength of 1270 MPa. Moreover, the specimen JSC440 in Table 1 is a non-plated 440 MPa grade steel plate.
レーザビームによる穴あけにより略矩形状の長穴３を形成し、その後スポット溶接し、試験片とした。 A substantially rectangular elongated hole 3 was formed by drilling with a laser beam, and then spot-welded to obtain a test piece.
図１０は、本実施例で用いた試験片８の形状を示す説明図である。
試験片８は、供試材９である鋼板にレーザビームにより穴あけした。レーザ穴あけには、ファイバーレーザを用い、ビーム径０．２ｍｍとし、速度１．０〜２．０ｍ／ｍｉｎ、アシストガス：窒素とした。
FIG. 10 is an explanatory diagram showing the shape of the test piece 8 used in this example.
The test piece 8 was drilled with a laser beam in a steel plate as the specimen 9. For laser drilling, a fiber laser was used, the beam diameter was 0.2 mm, the speed was 1.0 to 2.0 m / min, and the assist gas was nitrogen.
次に供試材である鋼板１０を、図１０に示すように重ね合わせ、重ね合わせ部で、スポット溶接を行ってスポット溶接部２，２を形成した。スポット溶接は、単相交流スポット溶接機を用い、ＤＲ型電極（先端の直径６ｍｍ，曲率半径４０ｍｍ）を用い、加圧力：４００ｋｇｆ，通電時間２０ｃｙｃ，電流値：ナゲット径６．０ｍｍが得られる電流値である。母材のビッカース硬さは、ＳＱ１５００：４７０、ＳＱＺ１５００：４７０、ＳＱ１８００：５６０、ＳＰＣ１２７０：４２０である。またスポット溶接のＨＡＺの最軟化部のビッカース硬さはＳＱ１５００：２９０、ＳＱＺ１５００：２９０、ＳＱ１８００：３９０、ＳＰＣ１２７０：２８０である。 Next, as shown in FIG. 10, the steel plate 10 as a test material was overlapped, and spot welding was performed at the overlapped portion to form spot welds 2 and 2. Spot welding uses a single-phase AC spot welder, DR type electrodes (tip diameter 6 mm, curvature radius 40 mm), applied pressure: 400 kgf, energization time 20 cyc, current value: current with nugget diameter 6.0 mm. Value. The Vickers hardness of the base material is SQ1500: 470, SQZ1500: 470, SQ1800: 560, SPC1270: 420. Moreover, the Vickers hardness of the softest part of HAZ of spot welding is SQ1500: 290, SQZ1500: 290, SQ1800: 390, and SPC1270: 280.
次に、各試験片８で引張試験を実施した。引張試験は評点間距離５０ｍｍとし、引張速度３ｍｍ／ｍｉｎ一定とした。破断までのひずみ（評点間隔５０ｍｍとし、鋼板にクラックが入りチャート上で急激に荷重が低下するひずみ）が３％未満の場合を×とし、３％以上３．５％未満を△とし、３．５％以上４％未満を□とし、４％以上のものを○とした。試験結果を図１１のグラフと表２にまとめて示す。 Next, a tensile test was performed on each test piece 8. In the tensile test, the distance between ratings was 50 mm, and the tensile speed was constant at 3 mm / min. 2. When the strain until breakage (grading interval is 50 mm, the steel plate is cracked and the load suddenly drops on the chart) is less than 3%, x is 3% or more and less than 3.5%, and Δ. 5% or more and less than 4% was indicated by □, and 4% or more by ◯. The test results are summarized in the graph of FIG.
図１１のグラフおよび表２に示すように、本発明例では、破断伸びが３．５％超であるのに対し、比較例ではスポット溶接のＨＡＺ最軟化部で小さいひずみで破断した（破断伸び３．０％未満）。 As shown in the graph of FIG. 11 and Table 2, in the example of the present invention, the elongation at break was over 3.5%, whereas in the comparative example, the HAZ softened part of spot welding broke with a small strain (breaking elongation). Less than 3.0%).
０ Ｂピラー／重ね溶接部材
００ ルーフレール／重ね溶接部材
１ Ｂピラーリンフォース／第１の構成部材
１ａ フランジ
１ｂ 端面
１ｃ 曲げＲ部
２ スポット溶接部／ナゲット（溶接金属）
２−１ Ｃ字状レーザ溶接部（溶接金属）
２−２ リング状レーザ溶接部（溶接金属）
２−３ 円状レーザ溶接部（溶接金属）
２−４ 円状アーク溶接部（溶接金属）
３ 長穴
４ ルーフレールアウタ／第１の構成部材
４ａ フランジ
５、１１ サイドパネルアウタ／第３の構成部材
６ Ａピラー
７ Ｂピラーインナ／第２の構成部材
８ 試験片
９，１０ 供試材
１２ ルーフレールインナ／第２の構成部材
１５ ヒンジリンフォース／第４の構成部材
0 B pillar / lap weld member 00 roof rail / lap weld member 1 B pillar reinforcement / first component 1a flange 1b end face 1c bend R portion 2 spot weld / nugget (welded metal)
2-1 C-shaped laser weld (welded metal)
2-2 Ring-shaped laser weld (welded metal)
2-3 Circular laser weld (welded metal)
2-4 Circular arc welds (welded metal)
3 Long hole 4 Roof rail outer / first component 4a Flange 5, 11 Side panel outer / third component 6 A pillar 7 B pillar inner / second component 8 Test piece 9, 10 Test material 12 Roof rail inner / Second component 15 hinge reinforcement / fourth component
Claims (11)
当該重ね溶接部材は、前記溶接により形成された溶接金属と、当該重ね溶接部材の長手方向に前記溶接金属に隣接して少なくとも前記第１の構成部材側に設けられた長穴とを有し、
前記長穴は、前記長手方向への長さが該長手方向と直交する方向への長さよりも長い形状を有するとともに長手方向の一部に平行部を有し、前記溶接金属の周囲に形成されているＨＡＺ最軟化部にかからないように設けられていること
を特徴とする重ね溶接部材。 At least a first structural member that is a steel plate having a tensile strength of 1180 MPa or more or a molded body thereof, and a second structural member that is another steel plate or a molded body thereof and is overlapped and welded to the first structural member. A lap weld member comprising:
The lap weld member has a weld metal formed by the welding, and a long hole provided at least on the first component side adjacent to the weld metal in the longitudinal direction of the lap weld member,
The elongated hole has a shape in which the length in the longitudinal direction is longer than the length in the direction orthogonal to the longitudinal direction, and has a parallel portion in a part of the longitudinal direction, and is formed around the weld metal. A lap weld member characterized in that the lap weld member is provided so as not to be applied to the HAZ softest part.
当該重ね溶接部材は、前記溶接により当該重ね溶接部材の長手方向に複数形成された溶接金属と、前記複数の溶接金属のうち少なくとも一対の隣接する２つの溶接金属の間で少なくとも第１の構成部材側に設けられた長穴とを有し、
前記長穴は、前記長手方向への長さが該長手方向と直交する方向への長さよりも長い形状を有するとともに長手方向の一部に平行部を有し、前記２つの溶接金属それぞれの周囲に形成されているＨＡＺ最軟化部にかからないように設けられていること
を特徴とする重ね溶接部材。 At least a first structural member that is a steel plate having a tensile strength of 1180 MPa or more or a molded body thereof, and a second structural member that is another steel plate or a molded body thereof and is overlapped and welded to the first structural member. A lap weld member comprising:
The lap weld member is at least a first constituent member between a weld metal formed in the longitudinal direction of the lap weld member by the welding and at least a pair of two adjacent weld metals among the plurality of weld metals. A slot provided on the side,
The elongated hole has a shape in which the length in the longitudinal direction is longer than the length in the direction orthogonal to the longitudinal direction, and has a parallel portion in a part of the longitudinal direction, A lap weld member, characterized in that the lap weld member is provided so as not to be applied to the HAZ softened portion formed in the above.
当該重ね溶接部材は、前記溶接により形成された１つ以上の溶接金属と、前記溶接金属のうち少なくとも１つの溶接金属において、前記重ね溶接部材の長手方向の両隣りに隣接してこれを挟むように第１の構成部材側に設けられた２つの長穴とを有し、
前記長穴は、前記長手方向への長さが該長手方向と直交する方向への長さよりも長い形状を有するとともに長手方向の一部に平行部を有し、前記溶接金属の周囲に形成されているＨＡＺ最軟化部にかからないように設けられていること
を特徴とする重ね溶接部材。 At least a first structural member that is a steel plate having a tensile strength of 1180 MPa or more or a molded body thereof, and a second structural member that is another steel plate or a molded body thereof and is overlapped and welded to the first structural member. A lap weld member comprising:
The lap weld member is sandwiched between one or more weld metals formed by the welding and at least one of the weld metals adjacent to both sides in the longitudinal direction of the lap weld member. Two elongated holes provided on the first component side,
The elongated hole has a shape in which the length in the longitudinal direction is longer than the length in the direction orthogonal to the longitudinal direction, and has a parallel portion in a part of the longitudinal direction, and is formed around the weld metal. A lap weld member characterized in that the lap weld member is provided so as not to be applied to the HAZ softest part.
ただし、ｔは第１の構成部材の板厚（ｍｍ）である。 The elongated hole is formed 2.0 mm or more away from the end of the weld metal in the longitudinal direction, and the length of the parallel part of the elongated hole in the longitudinal direction is 5 mm or more and 50 mm or less, and the longitudinal direction The lap weld member according to any one of claims 1 to 4, wherein a length of the elongated hole in a direction orthogonal to each other is 3 mm or more and 15√t (mm) or less.
Here, t is the plate thickness (mm) of the first component member.
前記第１の構成部材に部分的に少なくとも１つの、前記重ね溶接部材長手方向への長さが該長手方向と直交する方向への長さよりも長い形状を有するとともに長手方向の一部に平行部を有する長穴を設ける第１の工程と、
該長穴を形成された該第１の構成部材と前記第２の構成部材とを重ね合わせ、前記重ね溶接部材の長手方向に少なくとも前記長穴に隣接する部位で溶接し、当該溶接により形成される溶接金属の周囲のＨＡＺ最軟化部が前記長穴にかからないように前記溶接金属を形成する第２の工程とを備えること
を特徴とする重ね溶接部材の製造方法。 It is a method for manufacturing a lap weld member in which at least a first structural member that is a steel plate having a tensile strength of 1180 MPa or more or a molded body thereof and a second structural member that is another steel plate or a molded body thereof are overlapped and welded. And
At least one part of the first component member has a shape in which the length in the longitudinal direction of the lap weld member is longer than the length in the direction orthogonal to the longitudinal direction and is parallel to a part of the longitudinal direction A first step of providing a slot having
The first component member formed with the elongated hole and the second component member are overlapped, welded at least at a site adjacent to the elongated hole in the longitudinal direction of the lap weld member, and formed by the welding. And a second step of forming the weld metal so that the HAZ softened portion around the weld metal does not cover the elongated hole.
ただし、ｔは第１の構成部材の板厚（ｍｍ）である。 The elongated hole is formed 2.0 mm or more away from the end of the weld metal in the longitudinal direction, and the length of the parallel part of the elongated hole in the longitudinal direction is 5 mm or more and 50 mm or less, and the longitudinal direction method for producing a lap weld member according to claim 8 or claim 9 wherein the length length of the hole in the direction is 3mm or more 15√t (mm) or less perpendicular.
Here, t is the plate thickness (mm) of the first component member.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2013128737A JP6079466B2 (en) | 2013-06-19 | 2013-06-19 | Lap welded member of high strength steel plate and method for producing the same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2013128737A JP6079466B2 (en) | 2013-06-19 | 2013-06-19 | Lap welded member of high strength steel plate and method for producing the same |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2015003552A JP2015003552A (en) | 2015-01-08 |
| JP6079466B2 true JP6079466B2 (en) | 2017-02-15 |
Family
ID=52299828
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2013128737A Active JP6079466B2 (en) | 2013-06-19 | 2013-06-19 | Lap welded member of high strength steel plate and method for producing the same |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP6079466B2 (en) |
Families Citing this family (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP6281522B2 (en) * | 2015-04-07 | 2018-02-21 | Ｊｆｅスチール株式会社 | Method for determining side sill structure for vehicle |
| EP3254795A1 (en) * | 2016-06-09 | 2017-12-13 | Outokumpu Oyj | Resistance spot welding electrode and use of the electrode |
| MX2020004379A (en) | 2017-10-31 | 2020-08-20 | Nippon Steel Corp | Structural material. |
| JP2021142763A (en) * | 2018-04-11 | 2021-09-24 | 本田技研工業株式会社 | Body structure of automobile |
| JP6928719B2 (en) * | 2018-04-11 | 2021-09-01 | 本田技研工業株式会社 | Car body structure |
| EP3804899B1 (en) * | 2018-05-31 | 2023-08-30 | Nippon Steel Corporation | Spot welded joint, vehicle framework component provided with spot welded joint, and method of manufacturing spot welded joint |
| JP2019217546A (en) | 2018-06-22 | 2019-12-26 | 株式会社神戸製鋼所 | Joining method and joint structural body of plated steel sheet |
| JP6687178B1 (en) * | 2018-10-31 | 2020-04-22 | 日本製鉄株式会社 | Automotive frame members |
| WO2020090916A1 (en) * | 2018-10-31 | 2020-05-07 | 日本製鉄株式会社 | Automobile frame member |
| JP2020159489A (en) * | 2019-03-27 | 2020-10-01 | 日本製鉄株式会社 | Stacked-joint structure and automobile frame component |
| WO2020241500A1 (en) * | 2019-05-24 | 2020-12-03 | 日本製鉄株式会社 | Spot welded joint, and method for manufacturing spot welded joint |
| JP7453539B2 (en) | 2020-05-15 | 2024-03-21 | 日本製鉄株式会社 | Resistance spot welded joints, automobile parts, hat-shaped parts, and method for manufacturing resistance spot welded joints |
| FR3111320A1 (en) * | 2020-06-16 | 2021-12-17 | Psa Automobiles Sa | Spar reinforcement for motor vehicle |
| CN113020771B (en) * | 2021-03-23 | 2022-05-20 | 中国兵器科学研究院宁波分院 | Welding device and welding method for welding annular lap joint on lap joint piece |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002079388A (en) * | 2000-09-06 | 2002-03-19 | Nippon Steel Corp | Method for laser beam welding of shock-absorbing member having excellent shock absorption characteristic against axial collapse |
| JP2005349398A (en) * | 2004-06-08 | 2005-12-22 | Nissan Motor Co Ltd | Panel joining structure and joining method |
| JP5169475B2 (en) * | 2008-05-20 | 2013-03-27 | 新日鐵住金株式会社 | Resistance welding method |
| JP2012187617A (en) * | 2011-03-11 | 2012-10-04 | Nissan Motor Co Ltd | Joined body of high tensile strength steel sheet and resistance welding method for high tensile strength steel sheet |
-
2013
- 2013-06-19 JP JP2013128737A patent/JP6079466B2/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| JP2015003552A (en) | 2015-01-08 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP6079466B2 (en) | Lap welded member of high strength steel plate and method for producing the same | |
| JP6149522B2 (en) | Lap welded member of high strength steel plate and method for producing the same | |
| JP6191263B2 (en) | Lap welded member and manufacturing method thereof | |
| US10549388B2 (en) | Method of welding overlapped portion, method of manufacturing overlap-welded member, overlap-welded member, and automotive part | |
| JP5741648B2 (en) | Molded member and manufacturing method thereof | |
| JP4968201B2 (en) | Laser welded structural member and manufacturing method thereof | |
| US20180222536A1 (en) | Motor vehicle component made of triple-layer laminated steel | |
| KR102607041B1 (en) | B-pillar center beam and manufacturing method | |
| EP3762278B1 (en) | A body side structural frame of a vehicle | |
| JP6379819B2 (en) | Lap welding member, lap resistance seam welding method of lap welding member, and lap welding member for automobile having lap welding part | |
| JP7422080B2 (en) | Tailored blank, method for manufacturing tailored blank, press-formed product, and method for manufacturing press-formed product | |
| JP7151762B2 (en) | SPOT WELD JOINTS, MOTOR VEHICLE STRUCTURE COMPONENTS WITH SPOT WELD JOINTS, AND METHOD FOR MANUFACTURING THE SPOT WELD JOINTS | |
| WO2023157424A1 (en) | Lap welded joint, automobile skeleton member, and method for manufacturing lap welded joint | |
| JP2024033955A (en) | A method for manufacturing a lap welded joint, an automobile frame member, and a lap welded joint. |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| RD01 | Notification of change of attorney |
Free format text: JAPANESE INTERMEDIATE CODE: A7421 Effective date: 20151016 |
|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20160203 |
|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20160929 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20161004 |
|
| A521 | Written amendment |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20161107 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20161220 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20170102 |
|
| R151 | Written notification of patent or utility model registration |
Ref document number: 6079466 Country of ref document: JP Free format text: JAPANESE INTERMEDIATE CODE: R151 |
|
| S533 | Written request for registration of change of name |
Free format text: JAPANESE INTERMEDIATE CODE: R313533 |
|
| R350 | Written notification of registration of transfer |
Free format text: JAPANESE INTERMEDIATE CODE: R350 |