JP2002173755A - Hot-dip galvanized steel sheet having excellent spot weldability, and its manufacturing method - Google Patents
Hot-dip galvanized steel sheet having excellent spot weldability, and its manufacturing methodInfo
- Publication number
- JP2002173755A JP2002173755A JP2001305610A JP2001305610A JP2002173755A JP 2002173755 A JP2002173755 A JP 2002173755A JP 2001305610 A JP2001305610 A JP 2001305610A JP 2001305610 A JP2001305610 A JP 2001305610A JP 2002173755 A JP2002173755 A JP 2002173755A
- Authority
- JP
- Japan
- Prior art keywords
- steel sheet
- hot
- galvanized steel
- plating
- dip galvanized
- 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.)
- Granted
Links
Landscapes
- Coating With Molten Metal (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、自動車用などに用
いられる溶融亜鉛めっき鋼板に関し、特に、スポット溶
接性に優れた溶融亜鉛めっき鋼板およびその製造方法に
関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot-dip galvanized steel sheet used for automobiles and the like, and more particularly to a hot-dip galvanized steel sheet excellent in spot weldability and a method for producing the same.
【０００２】[0002]
【従来の技術】亜鉛系めっき鋼板は、その優れた犠牲防
食性のため自動車用防錆鋼板として国内外を問わず実用
化されている。なかでも、溶融亜鉛めっき鋼板、合金化
溶融亜鉛めっき鋼板は製造コストが低廉で高耐食性を有
することから、現在自動車用防錆鋼板の主流となってい
る。2. Description of the Related Art Galvanized steel sheets have been put to practical use in Japan and overseas as rust-resistant steel sheets for automobiles because of their excellent sacrificial corrosion resistance. Among them, hot-dip galvanized steel sheets and alloyed hot-dip galvanized steel sheets are currently the mainstream of rust-preventive steel sheets for automobiles because of their low production cost and high corrosion resistance.
【０００３】自動車製造工程で問題となる亜鉛系めっき
鋼板の性能の一つとして、スポット溶接性が挙げられ
る。周知のとおり、溶接性はめっき付着量と密接な関係
があり、付着量低減により溶接性は改善される。しかし
ながら、自動車用鋼板として十分な耐食性を確保するた
めに必要なめっき付着量を付与しようと思えば、亜鉛め
っき鋼板のスポット溶接性はめっきのない冷延鋼板など
との比較で劣っている。[0003] One of the performances of galvanized steel sheet which is a problem in the automobile manufacturing process is spot weldability. As is well known, the weldability is closely related to the coating weight, and the weldability is improved by reducing the coating weight. However, if an attempt is made to provide a coating weight necessary for ensuring sufficient corrosion resistance as a steel sheet for automobiles, the spot weldability of a galvanized steel sheet is inferior to that of a cold-rolled steel sheet without plating.
【０００４】亜鉛系めっき鋼板のスポット溶接性改善に
関しては、従来から以下に示すようないくつかの提案が
なされている。例えば、特開昭63−230861号公報などに
は、亜鉛めっき鋼板の表面にZnO を主体とする酸化皮膜
を付与することで、スポット溶接性を改善するという技
術が開示されており、この他にも亜鉛系めっきの表層に
酸化被膜を付与することでスポット溶接性を改善しよう
とする提案が多数開示されている。[0004] With respect to the improvement of spot weldability of galvanized steel sheets, several proposals as described below have hitherto been made. For example, Japanese Patent Application Laid-Open No. 63-230861 discloses a technique of improving spot weldability by providing an oxide film mainly composed of ZnO on the surface of a galvanized steel sheet. Also, many proposals for improving spot weldability by providing an oxide film on the surface layer of zinc-based plating have been disclosed.
【０００５】また、最近ではめっき最表層の金属Zn量、
Al2O3 量を規定した特開平10−330902号公報などや、酸
化膜量および酸化膜中のZn酸化膜量とAl酸化膜量との比
を規定した特開2000− 73183号公報などが開示されてい
る。しかしながら、上記技術は主に合金化溶融亜鉛めっ
き鋼板を対象にした技術である。[0005] Recently, the amount of metal Zn in the outermost layer of the plating,
And like JP 10-330902 discloses that defines the amount of Al 2 O 3, etc. JP 2000- 73183 discloses that defines the ratio of the Zn oxide film amount and the Al oxide film of the oxide film amount and oxide film It has been disclosed. However, the above technique is a technique mainly for an alloyed hot-dip galvanized steel sheet.
【０００６】すなわち、同じ溶融系亜鉛めっき鋼板であ
っても、めっき層が主に純亜鉛層からなる溶融亜鉛めっ
き鋼板と、めっき層がZn-Fe 金属間化合物からなる合金
化溶融亜鉛めっき鋼板とでは、そのスポット溶接時の溶
接挙動が根本的に異なり、溶融亜鉛めっき鋼板の溶接性
は、合金化溶融亜鉛めっき鋼板のそれに比べて著しく劣
るという問題がある。That is, even with the same hot-dip galvanized steel sheet, a hot-dip galvanized steel sheet in which the coating layer is mainly composed of a pure zinc layer and an alloyed hot-dip galvanized steel sheet in which the coating layer is made of a Zn-Fe intermetallic compound Thus, there is a problem that the welding behavior at the time of spot welding is fundamentally different, and the weldability of the hot-dip galvanized steel sheet is significantly inferior to that of the alloyed hot-dip galvanized steel sheet.
【０００７】一方、近年、従来問題であったドロスなど
の外観品質上の問題が解決されつつあるため、従来自動
車用防錆鋼板の主流であった合金化溶融亜鉛めっき鋼板
に代わって、溶融亜鉛めっき鋼板が自動車用防錆鋼板と
して採用される機運が高まってきた。溶融亜鉛めっき鋼
板は、合金化処理を施さないため製造コスト的にも有利
であり、今後の自動車用防錆鋼板としての需要の伸びが
予想される。On the other hand, in recent years, the problem of appearance quality such as dross, which has been a problem in the past, is being solved. Momentum that plated steel sheets are adopted as rust-preventive steel sheets for automobiles has increased. Hot-dip galvanized steel sheets are advantageous in terms of manufacturing cost because they are not subjected to alloying treatment, and demand for anticorrosion steel sheets for automobiles is expected to grow in the future.
【０００８】したがって、性能上の問題として溶融亜鉛
めっき鋼板のスポット溶接性の改善が切望されている。[0008] Therefore, improvement of spot weldability of hot-dip galvanized steel sheet has been desired as a performance problem.
【０００９】[0009]
【発明が解決しようとする課題】本発明は、前記した従
来技術の問題点を解決し、スポット溶接性に優れた溶融
亜鉛めっき鋼板およびその製造方法を提供することを目
的とする。SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems of the prior art and to provide a hot-dip galvanized steel sheet excellent in spot weldability and a method for producing the same.
【００１０】[0010]
【課題を解決するための手段】本発明者らは前記した溶
融亜鉛めっき鋼板のスポット溶接性改善に関して鋭意検
討した結果、下記の知見(1) 、(2) 、（3)を得、本発明
に至った。 (1) スポット溶接性の改善にはめっき層の性状の規定お
よび鋼板の降伏応力の規定が非常に重要であり、鋼板
の降伏応力：YSとめっき付着単位面積当たりのめっき
付着量：Ｗおよびめっき付着単位面積当たりのめっき
層中の総Al量：Ｘもしくはめっき／鋼板界面に存在する
Fe−Al金属間化合物中のAl量を除いためっき付着単位面
積当たりのめっき層中のAl量：Ｙとの関係を規定するこ
とによって、スポット溶接性が著しく改善される。Means for Solving the Problems The present inventors have conducted intensive studies on the improvement of spot weldability of the above-mentioned hot-dip galvanized steel sheet and obtained the following findings (1), (2) and (3). Reached. (1) To improve the spot weldability, it is very important to define the properties of the plating layer and the yield stress of the steel sheet. The yield stress of the steel sheet: YS and the coating weight per unit area of the coating weight: W and the plating Total amount of Al in plating layer per unit area of adhesion: X or exists at plating / steel plate interface
By defining the relationship with the amount of Al in the plating layer per unit area of plating: Y excluding the amount of Al in the Fe-Al intermetallic compound, spot weldability is significantly improved.
【００１１】(2) 上記した規定に加えて、めっき層中の
Pb、Sb、Bi、As、CdおよびSnの合計量（合計濃度）を規
定することによって、さらにスポット溶接性が向上す
る。 (3) 上記(1),(2) に加えて、溶融亜鉛めっきの場合、 鋼
板に１〜20ppm （：質量ppm ）のＢを添加するか、また
は0.010 〜0.050 ％（：質量％）のＰを添加することに
より、著しく連続打点性を向上させることができる。(2) In addition to the above rules,
By defining the total amount (total concentration) of Pb, Sb, Bi, As, Cd and Sn, spot weldability is further improved. (3) In addition to the above (1) and (2), in the case of hot-dip galvanization, 1 to 20 ppm (: mass ppm) of B is added to the steel sheet, or 0.010 to 0.050% (: mass%) of P By adding, the continuous hitting property can be remarkably improved.
【００１２】すなわち、第１の発明は、溶融亜鉛めっき
鋼板の降伏応力：YS(MPa) 、めっき付着単位面積当たり
のめっき付着量：Ｗ(g/m2)およびめっき付着単位面積当
たりのめっき層中の総Al量：Ｘ(g/m2)が下記式(1) およ
び(2) を満足することを特徴とするスポット溶接性に優
れた溶融亜鉛めっき鋼板である。 0.15≦〔YS／（５×Ｗ）〕−〔Ｘ／２〕………(1) 0.10≦Ｘ≦0.50 …………………………………(2) 第２の発明は、溶融亜鉛めっき鋼板の降伏応力：YS(MP
a) 、めっき付着単位面積当たりのめっき付着量：Ｗ(g/
m2)、めっき付着単位面積当たりのめっき層中の総Al
量：Ｘ(g/m2)、および、めっき／鋼板界面に存在するFe
−Al金属間化合物中のAl量を除いためっき付着単位面積
当たりのめっき層中のAl量：Ｙ(g/m2)が下記式(3) およ
び(4) を満足することを特徴とするスポット溶接性に優
れた溶融亜鉛めっき鋼板である。That is, the first invention relates to a yield stress of a galvanized steel sheet: YS (MPa), a coating weight per unit area of plating: W (g / m 2 ), and a plating layer per unit area of plating. A hot-dip galvanized steel sheet having excellent spot weldability, characterized in that the total amount of Al therein: X (g / m 2 ) satisfies the following formulas (1) and (2). 0.15 ≦ [YS / (5 × W)] − [X / 2] (1) 0.10 ≦ X ≦ 0.50 ………………………… (2) Yield stress of hot-dip galvanized steel sheet: YS (MP
a), Plating weight per unit area of plating: W (g /
m 2 ), total Al in the plating layer per unit area of plating adhesion
Amount: X (g / m 2 ) and Fe present at the plating / steel interface
-Characterized in that the amount of Al in the plating layer per unit area of plating excluding the amount of Al in the Al intermetallic compound: Y (g / m 2 ) satisfies the following formulas (3) and (4): Hot-dip galvanized steel sheet with excellent spot weldability.
【００１３】 0.30≦〔YS／（５×Ｗ）〕−〔Ｙ／２〕………(3) 0.10≦Ｘ≦0.50 …………………………………(4) 前記した第１の発明、第２の発明においては、めっき層
中のPb、Sb、Bi、As、CdおよびSnの合計量が、0.02質量
％以下（以下、本発明においては質量％をmass％と記
す）であることが好ましい（第１の発明の好適態様、第
２の発明の好適態様）。0.30 ≦ [YS / (5 × W)] − [Y / 2] (3) 0.10 ≦ X ≦ 0.50 ………………… (4) In the first invention and the second invention, the total amount of Pb, Sb, Bi, As, Cd, and Sn in the plating layer is 0.02 mass% or less (hereinafter, mass% is referred to as mass% in the present invention). (Preferred embodiment of the first invention, preferred embodiment of the second invention).
【００１４】また、前記した第１の発明、第１の発明の
好適態様、第２の発明、第２の発明の好適態様において
は、めっき層中のFe含有量が、好ましくは５mass％以
下、より好ましくは２mass％以下、さらに好ましくは１
mass％以下であることが好ましい。また、前記第１〜第
２の発明（それぞれ好適態様も含む）においては、鋼板
は、Ｂ：１〜20massppm および／またはＰ：0.010 〜0.
050 mass％を含有するものであることが好ましい。[0014] In the above-mentioned first invention, preferred embodiment of the first invention, second invention, and preferred embodiment of the second invention, the Fe content in the plating layer is preferably 5 mass% or less, More preferably 2 mass% or less, further preferably 1 mass% or less.
It is preferably at most mass%. In the first and second inventions (including the preferred embodiments, respectively), the steel sheet may have B: 1-20 massppm and / or P: 0.010-0.
Preferably, it contains 050 mass%.
【００１５】第３の発明は、鋼板を溶融亜鉛めっき浴に
浸漬後、引き上げてめっき付着量制御のためのガスワイ
ピングを行う溶融亜鉛めっき鋼板の製造方法において、
溶融亜鉛めっき浴中の溶解Al濃度：ＮAl（mass％）およ
びガスワイピング後のめっき付着単位面積当たりのめっ
き付着量：Ｗ(g/m2)が下記式(5) を満足する条件下で鋼
板に溶融亜鉛めっきを施すことを特徴とするスポット溶
接性に優れた溶融亜鉛めっき鋼板の製造方法である。[0015] A third invention relates to a method for producing a hot-dip galvanized steel sheet in which a steel sheet is immersed in a hot-dip galvanizing bath and then pulled up to perform gas wiping for controlling the coating weight.
The concentration of dissolved Al in the hot-dip galvanizing bath: N Al (mass%) and the amount of plating per unit area of plating after gas wiping: W (g / m 2 ) satisfy the following formula (5). This is a method for producing a hot-dip galvanized steel sheet having excellent spot weldability, characterized by subjecting the steel sheet to hot-dip galvanizing.
【００１６】 0.12≦ＮAl≦YS／（10×Ｗ）……………………(5) 上記式(5) 中、 YS：得られる溶融亜鉛めっき鋼板の降伏応力(MPa) を示す。前記した第３の発明においては、溶融亜鉛めっ
き浴中のPb、Sb、Bi、As、CdおよびSnの濃度の合計量
が、0.02mass％以下であることが好ましい（第３の発明
の好適態様）。0.12 ≦ N Al ≦ YS / (10 × W) (5) In the above formula (5), YS represents the yield stress (MPa) of the obtained hot-dip galvanized steel sheet. In the third aspect, the total amount of the concentrations of Pb, Sb, Bi, As, Cd, and Sn in the hot-dip galvanizing bath is preferably 0.02 mass% or less (preferred embodiment of the third aspect). ).
【００１７】また、前記した第３の発明、第３の発明の
好適態様においては、得られる溶融亜鉛めっき鋼板のめ
っき層中のFe含有量が、好ましくは５mass％以下、より
好ましくは２mass％以下、さらに好ましくは１mass％以
下であることが好ましい。また、前記第３の発明におい
ては、鋼板は、Ｂ：１〜20massppm および／またはＰ：
0.010 〜0.050 mass％を含有するものであることが好ま
しい。Further, in the third and third aspects of the present invention, the Fe content in the galvanized layer of the obtained hot-dip galvanized steel sheet is preferably 5 mass% or less, more preferably 2 mass% or less. And more preferably 1 mass% or less. Further, in the third invention, the steel sheet may have B: 1 to 20 massppm and / or P:
Preferably, it contains 0.010 to 0.050 mass%.
【００１８】[0018]
【発明の実施の形態】以下、本発明をさらに詳細に説明
する。本発明者らは、前記課題を解決するために、溶融
亜鉛めっき鋼板（：GI、非合金化溶融亜鉛めっき鋼板）
のスポット溶接時の溶接点におけるめっき層の溶融状態
および素地鋼板の機械的性質に着目して鋭意検討した結
果、下記知見を見出し、本発明に至った。BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. The present inventors have developed a galvanized steel sheet (: GI, non-alloyed hot-dip galvanized steel sheet) to solve the above-mentioned problems.
As a result of intensive studies focusing on the molten state of the plating layer at the welding point during spot welding and the mechanical properties of the base steel sheet, the following findings were found, and the present invention was reached.
【００１９】溶融亜鉛めっき鋼板のスポット溶接性を合
金化溶融亜鉛めっき鋼板や電気Zn-Ni 合金めっき鋼板、
電気Zn-Fe 合金めっき鋼板などの亜鉛系合金めっき鋼板
と比較した場合、以下に示すような溶融亜鉛めっき鋼板
特有のスポット溶接挙動が明らかになった。すなわち、
ウェルドローブを調査した結果、溶融亜鉛めっき鋼板の
場合、合金化めっき、合金めっきに比べて、同一ナゲッ
トを得るために必要な電流値が高く、適性溶接電流範囲
が高電流側にシフトするという問題が生じる。The spot weldability of hot-dip galvanized steel sheet is alloyed. Hot-dip galvanized steel sheet, electric Zn-Ni alloy coated steel sheet,
When compared with galvanized steel sheets such as electroplated Zn-Fe alloy coated steel sheets, the following spot welding behavior unique to hot-dip galvanized steel sheets was clarified. That is,
Investigation of weld lobes revealed that the galvanized steel sheet required a higher current value to obtain the same nugget than alloyed plating and alloy plating, causing the appropriate welding current range to shift to the higher current side. Occurs.
【００２０】このことはすなわち、高い電流値でスポッ
ト溶接しなければならないことを意味する。したがっ
て、連続打点溶接において、高電流での溶接が原因とな
って電極の損耗が早くなり、合金化溶融亜鉛めっき鋼板
に比べて連続打点性が劣るという問題を招く。This means that spot welding must be performed at a high current value. Therefore, in continuous spot welding, electrode wear is accelerated due to welding at a high current, which causes a problem that continuous spotting properties are inferior to alloyed hot-dip galvanized steel sheets.
【００２１】この溶接電流値が高電流値側にシフトする
原因は、下記の機構によるものと推定される。図１(a)
に、本発明者らが着目したスポット溶接時の溶接点にお
けるめっき層の溶融状態および素地鋼板同士の当接状態
を、縦断面図によって示す。また、図１(b) に溶融亜鉛
めっき層の層構造を、縦断面図によって示す。The reason why the welding current value shifts to the high current value side is presumed to be due to the following mechanism. Fig. 1 (a)
Next, the molten state of the plating layer and the abutting state of the base steel plates at the welding points at the time of spot welding, which the present inventors focused on, are shown by longitudinal sectional views. FIG. 1B shows the layer structure of the hot-dip galvanized layer in a longitudinal sectional view.
【００２２】なお、図１(a) において、１は素地鋼板
（素材鋼板）、２は溶融亜鉛めっき層（以下、めっき層
とも記す）、３は溶融した亜鉛、４は電極（溶接電
極）、５は隙間、d1はスポット溶接時の両素地鋼板当接
部の直径、d2はスポット溶接時の通電部の直径、Ｌは溶
接点近傍の両素地鋼板間の距離を示す。また、図１(b)
において、１は素地鋼板、２は溶融亜鉛めっき層（：め
っき層）、10はFe−Al金属間化合物であるFe−Al合金
層、11はFe−Zn金属間化合物であるFe−Zn合金層、12は
η相であるZn層を示す。In FIG. 1 (a), 1 is a base steel plate (base steel plate), 2 is a hot-dip galvanized layer (hereinafter also referred to as a plated layer), 3 is molten zinc, 4 is an electrode (welding electrode), 5 shows a gap, d 1 is the diameter of both the base steel sheet abutting portion during spot welding, d 2 is the diameter of the current supply portion during spot welding, L is the distance between the base steel sheet in the vicinity of the welding point. FIG. 1 (b)
In the above, 1 is a base steel sheet, 2 is a hot-dip galvanized layer (: plated layer), 10 is an Fe-Al alloy layer which is an Fe-Al intermetallic compound, and 11 is an Fe-Zn alloy layer which is an Fe-Zn intermetallic compound And 12 indicate a Zn layer which is an η phase.
【００２３】なお、図１(b) におけるFe−Zn合金層11、
Zn層12にはAlが含まれている。すなわち、溶融亜鉛めっ
き鋼板のめっき層２は純亜鉛が主体で融点が 420℃程度
と低いため、スポット溶接性時には通電後ただちに融解
する。この時、加圧された電極４で挟まれた鋼板間の密
着部周辺の隙間５は溶融した亜鉛３で埋まることにな
る。The Fe—Zn alloy layer 11 shown in FIG.
The Zn layer 12 contains Al. That is, since the plating layer 2 of the hot-dip galvanized steel sheet is mainly made of pure zinc and has a low melting point of about 420 ° C., it melts immediately after energization during spot welding. At this time, the gap 5 around the contact portion between the steel plates sandwiched between the pressed electrodes 4 is filled with the molten zinc 3.
【００２４】電極４による加圧部周辺の隙間５の間隔、
すなわち溶接点近傍の両素地鋼板間の距離Ｌが大きい場
合には、溶融亜鉛の周囲への広がりはさほど大きくない
が、隙間５が狭い場合には毛細管現象で溶融亜鉛は周囲
に広がることになる。この場合、結果的に通電面積が広
がり、めっき層が高融点なため隙間５に溶融亜鉛が広が
りにくい合金化溶融亜鉛めっきに比べ溶接電流密度が低
下する。The interval between the gaps 5 around the pressurized portion by the electrodes 4,
That is, when the distance L between the two base steel plates near the welding point is large, the spread of the molten zinc to the periphery is not so large, but when the gap 5 is narrow, the molten zinc spreads to the periphery by the capillary phenomenon. . In this case, as a result, the current-carrying area is widened, and the welding current density is reduced as compared with alloyed hot-dip galvanizing, in which the molten zinc is difficult to spread in the gap 5 because the plating layer has a high melting point.
【００２５】したがって、溶融亜鉛めっき鋼板の場合、
同じナゲット径を得るのに必要な電流値は、合金化溶融
亜鉛めっきに比べて高くなる。さらに、上記した理由
で、連続打点性も合金化溶融亜鉛めっき鋼板に比べ劣る
ようになる。本発明者らは、上記した溶融亜鉛めっき鋼
板のスポット溶接性の劣化機構に基づき、溶接性を改善
するための方針として下記(1) 、(2) に想到した。Therefore, in the case of a hot-dip galvanized steel sheet,
The current required to obtain the same nugget diameter is higher than that of galvannealed. Further, for the above-mentioned reason, the continuous hitting property becomes inferior to that of the galvannealed steel sheet. The present inventors have conceived the following (1) and (2) as a policy for improving weldability based on the above-described mechanism of deterioration of spot weldability of a galvanized steel sheet.
【００２６】(1) 電極加圧部周囲の鋼板間の隙間５をで
きるだけ大きくする。 (2) 隙間５に入り込んだ溶融亜鉛の周囲への拡散を防
ぐ。 上記方針に基づき、めっき層性状、鋼板性状と溶接性と
の関係について鋭意検討した結果、上記(1) の観点か
ら、溶融亜鉛めっき鋼板の機械的特性、特に溶融亜鉛め
っき鋼板の降伏応力：YSを規定し、さらに上記(2) の観
点から、周囲に流れ出る亜鉛の絶対量および亜鉛の濡れ
性を制御することによって、またさらに鋼板にＢおよび
／またはＰを添加することによって、溶融亜鉛めっき鋼
板であっても良好なスポット溶接性を確保することが可
能であることが明らかになった。(1) The gap 5 between the steel plates around the electrode pressing portion is made as large as possible. (2) The diffusion of the molten zinc that has entered the gap 5 to the surroundings is prevented. Based on the above policy, the authors conducted intensive studies on the relationship between the properties of the coating layer, the properties of the steel sheet and the weldability. From the viewpoint of (1) above, the mechanical properties of the hot-dip galvanized steel sheet, especially the yield stress of the hot-dip galvanized steel sheet: YS In addition, from the viewpoint of the above (2), by controlling the absolute amount of zinc flowing around and the wettability of zinc, and further adding B and / or P to the steel sheet, the hot-dip galvanized steel sheet Even in this case, it was clarified that good spot weldability can be ensured.
【００２７】また、溶融亜鉛の電極加圧部から周囲への
拡散を抑制する場合、亜鉛の濡れ性が悪い方が有利であ
り、このためには、めっき層中のAl量、特に溶融亜鉛中
に固溶しているAl量を少なくする必要があることを見出
した。この理由は、溶融亜鉛に固溶しているAlが、めっ
き表面に存在している酸化物を還元し、濡れ性を向上さ
せるためであると考えられる。In order to suppress the diffusion of the molten zinc from the electrode pressing portion to the surroundings, it is advantageous that the wettability of the zinc is poor. For this reason, the amount of Al in the plating layer, particularly It has been found that it is necessary to reduce the amount of Al dissolved in the solid solution. It is considered that the reason for this is that Al dissolved in the molten zinc reduces oxides present on the plating surface and improves wettability.
【００２８】しかし、一方では、めっき層の密着性を確
保するために、一定量以上のAl添加が必要である。さら
に、同様の考え方で、通常、溶融亜鉛めっき時にめっき
浴に含有されることの多いPb、Sb、Bi、As、CdおよびSn
に関して、めっき層中のPb、Sb、Bi、As、CdおよびSnの
合計量を0.02mass％以下と規制することが極めて有効で
あることが分かった。On the other hand, however, it is necessary to add a certain amount or more of Al in order to secure the adhesion of the plating layer. Further, with the same concept, Pb, Sb, Bi, As, Cd and Sn, which are often contained in a plating bath during hot-dip galvanizing.
It was found that regulating the total amount of Pb, Sb, Bi, As, Cd, and Sn in the plating layer to 0.02 mass% or less was extremely effective.
【００２９】すなわち、本発明は、溶融亜鉛めっき鋼板
のスポット溶接性を改善するために、溶融亜鉛めっき鋼
板の降伏応力をできるだけ上げ、めっき付着量を所定必
要量まで低減させ、かつ、めっき層中のAl量も可能な限
り下げ、さらに好ましくは、溶融亜鉛の濡れ性を良好に
するめっき層中のPb、Sb、Bi、As、CdおよびSnの合計量
を規制するものである。That is, in order to improve the spot weldability of a hot-dip galvanized steel sheet, the present invention increases the yield stress of the hot-dip galvanized steel sheet as much as possible, reduces the amount of coating applied to a predetermined required amount, Is also reduced as much as possible, and more preferably, the total amount of Pb, Sb, Bi, As, Cd and Sn in the plating layer for improving the wettability of the molten zinc.
【００３０】さらに、上記した溶融亜鉛めっき鋼板の降
伏応力、めっき付着量およびめっき層中Al量の規定は独
立でなく、下記式(1) または(3) かつ式(2)[式(4)]で与
えられる関係を満足することが必要であることが明らか
となった。 0.15≦〔YS／（５×Ｗ）〕−〔Ｘ／２〕………(1) 0.10≦Ｘ≦0.50……………………………………(2)[(4)] 0.30≦〔YS／（５×Ｗ）〕−〔Ｙ／２〕………(3) なお、上記式(1) 〜(4) 中、 YS：溶融亜鉛めっき鋼板の降伏応力(MPa) Ｗ：めっき付着単位面積当たりのめっき付着量(g/m2) Ｘ：めっき付着単位面積当たりのめっき層中の総Al量(g
/m2) Ｙ：めっき／鋼板界面に存在するFe−Al金属間化合物中
のAl量を除いためっき付着単位面積当たりのめっき層中
のAl量(g/m2) を示す。Further, the rules for the yield stress, the coating weight and the amount of Al in the coating layer of the hot-dip galvanized steel sheet are not independent, and are defined by the following formulas (1) or (3) and (2) [formula (4). It became clear that it was necessary to satisfy the relationship given by 0.15 ≦ [YS / (5 × W)] − [X / 2] (1) 0.10 ≦ X ≦ 0.50 ……………………… (2) [(4)] 0.30 ≦ [YS / (5 × W)] − [Y / 2] (3) In the above formulas (1) to (4), YS: yield stress (MPa) of hot-dip galvanized steel sheet W: X: Amount of plating per unit area of plating (g / m 2 ) X: Total amount of Al in plating layer per unit area of plating (g
/ m 2 ) Y: Shows the amount of Al (g / m 2 ) in the plating layer per unit area of plating adhesion excluding the amount of Al in the Fe-Al intermetallic compound present at the plating / steel plate interface.
【００３１】上記した式(1) 中の｛〔YS／（５×Ｗ）〕
−〔Ｘ／２〕｝が0.15未満の場合、または式(3) 中の
｛〔YS／（５×Ｗ）〕−〔Ｙ／２〕｝が0.30未満の場
合、スポット溶接性が低下する。なお、式(1) および式
(3) の右辺に対して特に上限は定めない。何故ならば、
素地鋼板（素材鋼板）により様々にYSは変化するからで
ある。｛[YS / (5 × W)] in the above equation (1)
When [[X / 2]] is less than 0.15, or when [[YS / (5 × W)]-[Y / 2]} in the formula (3) is less than 0.30, the spot weldability decreases. Equation (1) and equation (1)
There is no particular upper limit for the right side of (3). because,
This is because YS changes in various ways depending on the base steel sheet (material steel sheet).
【００３２】また、式(2)[(4)]中のＸが0.10以上かつ0.
50以下の範囲に、めっき密着性とスポット溶接性の両方
が良好となる領域がある。さらに、本発明によれば、溶
融亜鉛の濡れ性を向上させるめっき層中のPb、Sb、Bi、
As、CdおよびSnの合計量を0.02mass％以下に規制するこ
とによって、スポット溶接性向上効果がより効果的に発
現することが明らかとなった。In the formula (2) [(4)], X is 0.10 or more and 0.1.
Within the range of 50 or less, there is a region where both plating adhesion and spot weldability are good. Further, according to the present invention, Pb, Sb, Bi,
It became clear that the effect of improving spot weldability was more effectively exhibited by regulating the total amount of As, Cd and Sn to 0.02 mass% or less.
【００３３】すなわち、本発明によれば、めっき層中の
Pb、Sb、Bi、As、CdおよびSnの合計量を0.02mass％以下
に規制することによって、スポット溶接性向上効果を安
定して得ることができる。なお、本発明においては溶融
亜鉛めっき鋼板の溶融亜鉛めっき層中のFe含有量が好ま
しくは５mass％以下、より好ましくは２mass％以下、さ
らに好ましくは１mass％以下であることが好ましい。That is, according to the present invention, in the plating layer
By regulating the total amount of Pb, Sb, Bi, As, Cd and Sn to 0.02 mass% or less, the effect of improving spot weldability can be stably obtained. In the present invention, the Fe content in the hot-dip galvanized steel sheet is preferably 5 mass% or less, more preferably 2 mass% or less, and even more preferably 1 mass% or less.
【００３４】これは、前記した合金化溶融亜鉛めっき鋼
板のように、めっき層中のFe含有量が５mass％を超える
場合、めっき密着性を低下させるFe−Zn合金層の成長に
よって、プレス成形時のめっき密着性が低下するためで
ある。本発明の溶融亜鉛めっき鋼板のめっき付着量は、
要求される耐食性に従って定めることができ、特に制限
を受けるものではないが、めっき付着量が、鋼板片面当
たり、すなわち、めっき付着単位面積当たり20〜300g/m
2 であることが好ましく、さらには20〜100g/m2 である
ことがより好ましい。This is because, when the Fe content in the plating layer exceeds 5 mass%, as in the above-mentioned alloyed hot-dip galvanized steel sheet, the growth of the Fe—Zn alloy layer that reduces the plating adhesion causes a problem during press forming. This is because the plating adhesion of the metal is reduced. The coating weight of the hot-dip galvanized steel sheet of the present invention is:
It can be determined according to the required corrosion resistance, and is not particularly limited, but the coating weight per one side of the steel sheet, that is, 20 to 300 g / m
2 , more preferably 20 to 100 g / m 2 .
【００３５】これは、めっき付着量が20g/m2未満の場
合、耐食性が低下し、300g/m2 を超える場合、耐食性向
上効果が実用上飽和し経済的でないためである。前記し
た本発明の溶融亜鉛めっき鋼板を得るための製造方法と
しては、通常の連続溶融亜鉛めっきラインにおいて、溶
融亜鉛めっき浴中の溶解Al濃度：ＮAl（mass％）を、め
っき付着単位面積当たりのめっき付着量（ガスワイピン
グによるめっき付着量制御後のめっき付着量）：Ｗ(g/m
2)および溶融亜鉛めっき鋼板の降伏応力：YS(MPa) との
関係において、下記式(5) なる関係を満足することが必
要になる。This is because when the coating weight is less than 20 g / m 2 , the corrosion resistance is reduced, and when it exceeds 300 g / m 2 , the effect of improving the corrosion resistance is practically saturated and is not economical. As a manufacturing method for obtaining the hot-dip galvanized steel sheet of the present invention described above, in a normal continuous hot-dip galvanizing line, the dissolved Al concentration in the hot-dip galvanizing bath: N Al (mass%) is measured per unit area of plating adhesion. Coating weight (coating weight after plating weight control by gas wiping): W (g / m
In relation to 2 ) and the yield stress of the hot-dip galvanized steel sheet: YS (MPa), it is necessary to satisfy the following equation (5).
【００３６】0.12≦ＮAl≦YS／（10×Ｗ）………(5) めっき浴に溶解しているAlの濃度：ＮAlの上限値は、前
記したように、良好なスポット溶接性を確保するため
に、めっき付着量：Ｗ(g/m2)および溶融亜鉛めっき鋼板
の降伏応力：YS(MPa) との関係において制約されるめっ
き層中のAl量を制御するために規定されるものである。0.12 ≦ N Al ≦ YS / (10 × W) (5) Concentration of Al dissolved in the plating bath: The upper limit of N Al is, as described above, good spot weldability. In order to ensure, the coating amount is specified in order to control the amount of Al in the coating layer which is restricted in relation to the relationship between the coating weight: W (g / m 2 ) and the yield stress of the galvanized steel sheet: YS (MPa). Things.
【００３７】また、その下限値は、めっき密着性の観点
から規定され、溶融亜鉛めっき浴中の溶解Al濃度：ＮAl
（mass％）がこの値より小さくなると、めっき密着性が
著しく低下する。なお、上記した本発明の溶融亜鉛めっ
き鋼板の製造方法においては、素材鋼板の降伏応力、ガ
スワイピングによるめっき付着量制御および溶融亜鉛め
っき浴中の溶解Al濃度などに基づいて、溶融亜鉛めっき
浴中の溶解Al濃度：ＮAl（mass％）、めっき付着単位面
積当たりのめっき付着量（ガスワイピングによるめっき
付着量制御後のめっき付着量）：Ｗ(g/m2)および溶融亜
鉛めっき鋼板の降伏応力：YS(MPa) が前記式(5) なる関
係を満足するように制御することができる。The lower limit is defined from the viewpoint of plating adhesion, and the dissolved Al concentration in the hot dip galvanizing bath: N Al
If (mass%) is smaller than this value, the plating adhesion will be significantly reduced. In the method for producing a hot-dip galvanized steel sheet according to the present invention described above, the yield stress of the base steel sheet, the control of the amount of coating applied by gas wiping and the concentration of dissolved Al in the hot-dip galvanizing bath, etc. Al concentration: N Al (mass%), coating weight per unit area of coating (coating weight after controlling coating weight by gas wiping): W (g / m 2 ) and yield of hot-dip galvanized steel sheet Stress: YS (MPa) can be controlled so as to satisfy the relationship represented by the above equation (5).
【００３８】さらに、本発明においては、溶融亜鉛の濡
れ性を向上させるめっき層中のPb、Sb、Bi、As、Cdおよ
びSnの合計量を0.02mass％以下に規制することによっ
て、スポット溶接性向上効果がより効果的に発現するた
め、溶融亜鉛めっき浴中のPb、Sb、Bi、As、CdおよびSn
の濃度の合計量を、0.02mass％以下に規制することが好
ましい。Further, in the present invention, the total amount of Pb, Sb, Bi, As, Cd and Sn in the plating layer for improving the wettability of the hot-dip zinc is regulated to 0.02 mass% or less, so that the spot weldability is improved. Pb, Sb, Bi, As, Cd and Sn in the hot-dip galvanizing bath because the improvement effect appears more effectively
Is preferably regulated to 0.02 mass% or less.
【００３９】なお、上記した本発明においては、前記し
たと同様の理由で、得られる溶融亜鉛めっき鋼板のめっ
き層中のFe含有量が、好ましくは５mass％以下、より好
ましくは２mass％以下、さらに好ましくは１mass％以下
であることが好ましい。以上、本発明について述べた
が、前記したように本発明においては溶融亜鉛めっきの
濡れ性の観点から、めっき層中のPb、Sb、Bi、As、Cdお
よびSnの合計量を規制し、そのために製造時の溶融亜鉛
めっき浴中のPb、Sb、Bi、As、CdおよびSnの濃度の合計
量を規制することが好ましいが、その他の元素、例えば
溶融亜鉛めっき鋼板の耐食性向上を目的として添加され
るMg、Cr、Mn、CoおよびNiなどの元素はこれを制限する
ものでなく、めっき層中にこれらの元素を１種または２
種以上含有した溶融亜鉛めっき鋼板も本発明の溶融亜鉛
めっき鋼板に包含される。In the present invention, for the same reason as described above, the Fe content in the galvanized layer of the obtained hot-dip galvanized steel sheet is preferably 5% by mass or less, more preferably 2% by mass or less, and furthermore Preferably, it is 1 mass% or less. As described above, the present invention has been described.In the present invention, as described above, from the viewpoint of hot-dip galvanizing, the total amount of Pb, Sb, Bi, As, Cd, and Sn in a plating layer is regulated. It is preferable to regulate the total amount of the concentrations of Pb, Sb, Bi, As, Cd and Sn in the hot-dip galvanizing bath during production, but other elements, for example, added for the purpose of improving the corrosion resistance of the hot-dip galvanized steel sheet The elements such as Mg, Cr, Mn, Co and Ni are not limited thereto, and one or two of these elements may be contained in the plating layer.
Hot-dip galvanized steel sheets containing more than one kind are also included in the hot-dip galvanized steel sheets of the present invention.
【００４０】なお、前記した式(1) および(3) における
考察では、めっき付着単位面積当たりのめっき層中の総
Al量：Ｘ(g/m2)には制限を設けていない。しかし、Ｘが
0.10g/m2未満では、めっき密着性が著しく劣り、また、
Ｘが0.50g/m2を超えると固溶しているAl量が過大となり
溶接は不可能である。したがって、Ｘは前記式(2)
〔(4) 〕を満たす必要がある。It should be noted that the considerations in the above equations (1) and (3) indicate that the total
Al amount: X (g / m 2 ) is not limited. But X is
If it is less than 0.10 g / m 2 , the plating adhesion is remarkably poor, and
If X exceeds 0.50 g / m 2 , the amount of Al dissolved in the solid solution becomes excessive and welding is impossible. Therefore, X is expressed by the formula (2)
It is necessary to satisfy [(4)].
【００４１】また、本発明においては素材鋼板の鋼種も
特に制限を受けるものではなく、溶融亜鉛めっき鋼板の
降伏応力：YSが前記した式(1) または式(3) を満足して
いれば、それ以外の機械的特性、鋼中成分、製造方法な
どは特に制限を受けるものではないが、好ましいのは、
鋼板に、Ｂ：１〜20massppm および／またはＰ：0.010
〜0.050 mass％を含有させることである。In the present invention, the steel type of the base steel sheet is not particularly limited. If the yield stress: YS of the hot-dip galvanized steel sheet satisfies the above formula (1) or (3), Other mechanical properties, components in steel, manufacturing method and the like are not particularly limited, but are preferably
B: 1 to 20 massppm and / or P: 0.010
-0.050 mass%.
【００４２】本発明で好ましい鋼中成分としてＢおよび
Ｐを規定した理由は、 以下による。上述のように、スポ
ット溶接時に溶接電流密度を確保して溶接できるように
するためには、 鋼板間での溶融亜鉛の広がりを極力抑制
する必要があり、そのために加圧部周囲の鋼板間の隙間
をできるだけ広くする必要がある。この場合、特に重要
となる鋼板側の特性として、溶接時に鋼板がさらされる
温度での強度、いわゆる高温強度が挙げられる。すなわ
ち、この高温強度が高ければ溶接時の溶融亜鉛の広がり
は抑制され、良好な溶接性が確保できる。本発明では、
素材のもともとの機械的性質を損なわずに高温強度を確
保するためには、鋼中に所定量のＢおよび／またはＰを
添加することが極めて有効であることが判明した。すな
わち、鋼中へ１〜20massppm のＢおよび／または0.010
〜0.050mass ％のＰを含有させることにより溶融亜鉛め
っき鋼板の連続打点性が著しく向上することが明らかに
なった。含有させるＢが１massppm 未満では連続打点性
改善効果が不十分であるからであり、また20massppm 超
では該効果が飽和するためコスト的に不利になるからで
ある。また、含有させるＰが0.010mass ％未満では連続
打点性改善効果が不十分であるからであり、また0.050m
ass ％超では該効果が飽和するのみならず素材の十分な
加工性を確保するのが困難となるからである。The reasons for defining B and P as preferred components in steel in the present invention are as follows. As described above, in order to secure the welding current density during spot welding and enable welding, it is necessary to minimize the spread of molten zinc between the steel sheets, and therefore, between the steel sheets around the pressurized part The gap must be as wide as possible. In this case, a particularly important property on the steel sheet side is strength at a temperature to which the steel sheet is exposed during welding, so-called high-temperature strength. That is, if the high-temperature strength is high, the spread of molten zinc during welding is suppressed, and good weldability can be ensured. In the present invention,
It has been found that it is extremely effective to add a predetermined amount of B and / or P to steel in order to secure high-temperature strength without impairing the original mechanical properties of the material. That is, 1-20 mass ppm of B and / or 0.010 mass ppm
It has been clarified that the incorporation of up to 0.050 mass% of P significantly improves the continuous hitting property of the hot-dip galvanized steel sheet. If the B content is less than 1 mass ppm, the effect of improving the continuous hitting property is insufficient, and if it exceeds 20 mass ppm, the effect is saturated and the cost is disadvantageous. On the other hand, if the content of P is less than 0.010 mass%, the effect of improving the continuous hitting property is insufficient.
If the content exceeds ass%, not only the effect is saturated but also it becomes difficult to ensure sufficient workability of the material.
【００４３】なお、素材鋼板としては、上記Ｂおよび／
またはＰに加え、Ｃ：0.0010〜0.0050mass％、Si：0.00
5 〜0.050mass ％、Mn：0.01〜1.0mass ％、Al：0.02〜
0.05mass％、Ti：0.0001〜0.10mass％、Nb：0.0001〜0.
05mass％を含有し、残部鉄および不可避的不純物からな
るものが好ましい。その理由は以下のとおりである。 Ｃ：0.0010〜0.0050mass％ 本発明品は主に自動車のパネル類を対象としたものであ
る。周知のとおり、近年自動車のパネルには良好な加工
性、特に複雑な形状にも加工できるような深絞り性が要
求されている。このような加工性を確保するためには、
Ｃ量は0.0050mass％以下にすることが好ましい。また、
下限は該効果とコストとの関係で決定されるが、0.0010
mass％以上とすることが好ましい。As the material steel plate, B and / or
Or, in addition to P, C: 0.0010 to 0.0050 mass%, Si: 0.00
5 to 0.050 mass%, Mn: 0.01 to 1.0 mass%, Al: 0.02 to
0.05 mass%, Ti: 0.0001-0.10 mass%, Nb: 0.0001-0.
The one containing 0.05 mass% and the balance being iron and unavoidable impurities is preferable. The reason is as follows. C: 0.0010 to 0.0050 mass% The present invention is mainly intended for automobile panels. As is well known, in recent years, panels for automobiles have been required to have good workability, particularly deep drawability for processing even complicated shapes. In order to ensure such workability,
The C content is preferably set to 0.0050 mass% or less. Also,
The lower limit is determined by the relationship between the effect and cost, but 0.0010
It is preferable to be at least mass%.
【００４４】Si：0.005 〜0.050mass ％ Siは、0.050mass ％を超えるとめっき性が劣化する傾向
があり、0.050mass ％以下とすることが好ましい。ま
た、下限は該効果とコストとの関係で決定されるが、0.
005 mass％以上とすることが好ましい。 Mn：0.01〜1.0mass ％ Mnは、ｒ値の低下と耐食性の観点から1.0 mass％以下と
することが好ましい。また、下限は該効果とコストとの
関係で決定されるが、0.01mass％以上とすることが好ま
しい。Si: 0.005 to 0.050% by mass When Si exceeds 0.050% by mass, the plating property tends to deteriorate, and is preferably 0.050% by mass or less. Also, the lower limit is determined by the relationship between the effect and cost,
It is preferably at least 005 mass%. Mn: 0.01 to 1.0 mass% Mn is preferably set to 1.0 mass% or less from the viewpoint of a decrease in r value and corrosion resistance. The lower limit is determined by the relationship between the effect and the cost, but is preferably 0.01% by mass or more.
【００４５】Al：0.02〜0.05mass％ Alは脱酸剤として0.02mass％以上の添加が好ましい。ま
た、多すぎると介在物が増加するため0.05mass％以下と
することが好ましい。 Ti：0.0001〜0.10mass％ Tiは鋼中の有害物であるＮをTiN として固定させるため
に0.0001mass％以上添加することが好ましい。また、多
すぎるとTiC が増え加工性を劣化させるので、0.10mass
％以下とすることが好ましい。Al: 0.02 to 0.05 mass% Al is preferably added as a deoxidizing agent in an amount of 0.02 mass% or more. If the content is too large, inclusions increase, so that the content is preferably set to 0.05 mass% or less. Ti: 0.0001 to 0.10 mass% Ti is preferably added in an amount of 0.0001 mass% or more to fix N, which is a harmful substance in steel, as TiN. On the other hand, if the content is too large, TiC increases and the workability deteriorates.
% Is preferable.
【００４６】Nb：0.0001〜0.05mass％ NbはNbC として熱延中に熱延結晶粒を制御するためとＣ
を固定させるために0.0001mass％以上添加することが好
ましい。また、添加しすぎると微細析出物としてｒ値を
低下させるため、0.05mass％以下とすることが好まし
い。Nb: 0.0001 to 0.05 mass% Nb is used as NbC to control hot-rolled crystal grains during hot-rolling.
Is preferably added in an amount of 0.0001 mass% or more in order to fix. Further, if added too much, the r value is reduced as fine precipitates, so that the content is preferably 0.05 mass% or less.
【００４７】[0047]
【実施例】以下、本発明を実施例に基づいてさらに具体
的に説明する。 （実施例１〜15、比較例１〜６）表１に示す組成になる
極低炭素冷延鋼板を素材とし、表２に示すめっき条件で
連続溶融亜鉛めっきラインで溶融亜鉛めっきを施した。EXAMPLES The present invention will be described below more specifically based on examples. (Examples 1 to 15, Comparative Examples 1 to 6) An ultra-low carbon cold rolled steel sheet having the composition shown in Table 1 was used as a material, and hot dip galvanizing was performed in a continuous galvanizing line under the plating conditions shown in Table 2.
【００４８】次に、得られた溶融亜鉛めっき鋼板のめっ
き層に関して、めっき層を５mass％塩酸に溶解し、溶解
液を誘導結合プラズマ発光分光分析装置（ICP ）を用い
て分析し、めっき付着単位面積当たりのめっき層中の総
Al量、めっき付着単位面積当たりのめっき付着量並びに
めっき層中のPb、Sb、Bi、As、CdおよびSnの合計量（合
計濃度）およびFe含有量（Fe濃度）を求めた。Next, with respect to the plating layer of the obtained hot-dip galvanized steel sheet, the plating layer was dissolved in 5 mass% hydrochloric acid, and the solution was analyzed using an inductively coupled plasma emission spectrometer (ICP) to determine the plating adhesion unit. Total in the plating layer per area
The amount of Al, the amount of plating per unit area of plating and the total amount (total concentration) of Pb, Sb, Bi, As, Cd and Sn in the plating layer and the Fe content (Fe concentration) were determined.
【００４９】また、めっき鋼板を発煙硝酸に浸漬させ、
純亜鉛層およびZn−Fe合金層を溶解し、めっき／鋼板界
面に存在するFe−Al金属間化合物のみを残存させた状態
とした後、Fe−Al金属間化合物を上記と同様に５mass％
塩酸に溶解し、溶解液を ICPで分析し、Fe−Al金属間化
合物中のめっき付着単位面積当たりのAl量を定量した。Further, the plated steel sheet is immersed in fuming nitric acid,
After dissolving the pure zinc layer and the Zn-Fe alloy layer to leave only the Fe-Al intermetallic compound present at the plating / steel plate interface, the Fe-Al intermetallic compound was 5 mass% in the same manner as described above.
The solution was dissolved in hydrochloric acid, and the solution was analyzed by ICP to determine the amount of Al per unit area of plating adhesion in the Fe-Al intermetallic compound.
【００５０】表１に、上記で得られためっき層性状およ
び溶融亜鉛めっき鋼板の降伏応力：YSの測定結果を示
す。また、得られた溶融亜鉛めっき鋼板に対して、下記
に示す溶接条件でスポット溶接性の調査を行い、板厚：
ｔ(mm)に対して 4.5×（ｔ1/2 ）で示されるナゲット径
が得られる電流値：Ｉ0(kA) および連続打点数の調査を
行った。Table 1 shows the properties of the coating layer obtained above and the measurement results of the yield stress: YS of the hot-dip galvanized steel sheet. In addition, spot weldability of the obtained hot-dip galvanized steel sheet was investigated under the following welding conditions,
The current value: I 0 (kA) at which a nugget diameter represented by 4.5 × (t 1/2 ) with respect to t (mm) was obtained, and the number of continuous hits were investigated.
【００５１】なお、連続打点性調査における溶接電流値
は、４×（ｔ1/2 ）で示されるナゲット径が得られる電
流値：Ｉ1(kA) および最小の溶着電流値：Ｉ2(kA) の平
均値を用いた。 （スポット溶接条件：） 電極；ＤＲ型、先端径： 6.0mmφ、先端曲率半径：40m
m、外径：16mmφ、材質：Cu−Cr 溶接条件；通電時間：10サイクル、加圧力：1960Ｎ（20
0kgf） 加圧条件；通電前：30サイクル、通電後：７サイクル アップスロープ、ダウンスロープ無し 連続打点溶接速度：１点／２秒 表２に、上記で得られたスポット溶接性の調査結果を示
す。Incidentally, the welding current value in the continuous spotting investigation was a current value: I 1 (kA) at which a nugget diameter represented by 4 × (t 1/2 ) was obtained and a minimum welding current value: I 2 (kA) ) Was used. (Spot welding conditions :) Electrode; DR type, tip diameter: 6.0mmφ, tip radius of curvature: 40m
m, Outer diameter: 16mmφ, Material: Cu-Cr Welding conditions; Energizing time: 10 cycles, Pressure: 1960N (20
0kgf) Pressurizing condition; 30 cycles before energization, 7 cycles after energization No up slope, down slope Continuous spot welding speed: 1 point / 2 seconds Table 2 shows the results of the spot weldability investigation obtained above. .
【００５２】さらに、得られた溶融亜鉛めっき鋼板に対
して、下記に示す条件でデュポン衝撃試験を行い、めっ
き密着性を評価した。 （めっき密着性評価方法：） デュポン衝撃試験の条件； 荷重： 9.8Ｎ（1kgf）、落重高さ：100cm 、ポンチ径：
6.35mm（1/4 inch） 溶融亜鉛めっき鋼板のデュポン衝撃試験後、凸部に対し
てセロハンテープ剥離を行いめっき剥離量に応じて評点
を１〜５とした。Further, the obtained hot-dip galvanized steel sheet was subjected to a DuPont impact test under the following conditions to evaluate the plating adhesion. (Plating adhesion evaluation method :) DuPont impact test conditions; Load: 9.8 N (1 kgf), Dropping height: 100 cm, Punch diameter:
After the DuPont impact test on the 6.35 mm (1/4 inch) hot-dip galvanized steel sheet, cellophane tape peeling was performed on the convex portions, and the scores were 1 to 5 according to the amount of plating peeling.
【００５３】評価方法は、テープにより剥離しためっき
層について、面積100mm2あたりの亜鉛の蛍光Ｘ線カウン
トを測定してカウント数（cps ）が 100未満を評点５、
100以上、 200未満を評点４、200 以上、 300未満を評
点３、300 以上、 400未満を評点２、400 以上を評点１
とした。すなわち、めっき剥離の無いものが評点５で、
評点１になるに従いめっき剥離量が多くなる。The evaluation method was as follows. For the plating layer peeled off by the tape, the fluorescent X-ray count of zinc per 100 mm 2 area was measured, and the count number (cps) was less than 100.
100 or more, less than 200, score 4, 200 or more, less than 300, score 3, 300 or more, less than 400, score 2, 400 or more, score 1
And In other words, those without plating peeling were rated 5,
As the score becomes 1, the amount of plating peeling increases.
【００５４】表２に、上記で得られめっき密着性の評価
結果を示す。 （比較例７〜９）表１に示す組成になる極低炭素冷延鋼
板を素材とした合金化溶融亜鉛めっき鋼板、電気Zn−Ni
合金めっき鋼板および電気Zn−Fe合金めっき鋼板に関し
て前記した方法と同様の方法でスポット溶接性、めっき
密着性を評価した。Table 2 shows the evaluation results of the plating adhesion obtained above. (Comparative Examples 7 to 9) An alloyed hot-dip galvanized steel sheet made of an ultra-low carbon cold-rolled steel sheet having the composition shown in Table 1 and electric Zn-Ni
The spot weldability and plating adhesion were evaluated in the same manner as described above for the alloy plated steel sheet and the electric Zn-Fe alloy plated steel sheet.
【００５５】表３に、得られた評価結果を示す。表２お
よび表３に示すように、溶融亜鉛めっき鋼板の降伏応
力、めっき付着単位面積当たりのめっき付着量およびめ
っき付着単位面積当たりのめっき層中Al量の３者を規定
し、またはさらにＢおよび／またはＰ所定量含有する鋼
板を用いた本発明の溶融亜鉛めっき鋼板は、従来の溶融
亜鉛めっき鋼板に比べて優れたスポット溶接性を有す
る。Table 3 shows the obtained evaluation results. As shown in Tables 2 and 3, the yield stress of the hot-dip galvanized steel sheet, the amount of plating per unit area of plating and the amount of Al in the plating layer per unit area of plating are defined, or B and The hot-dip galvanized steel sheet of the present invention using a steel sheet containing a predetermined amount of P has a higher spot weldability than a conventional hot-dip galvanized steel sheet.
【００５６】また、本発明の溶融亜鉛めっき鋼板は、優
れたスポット溶接性を有すると共に、合金化溶融亜鉛め
っき鋼板、電気Zn−Ni合金めっき鋼板および電気Zn−Fe
合金めっき鋼板に対して、優れためっき密着性を有す
る。Further, the hot-dip galvanized steel sheet of the present invention has excellent spot weldability, and has an alloyed hot-dip galvanized steel sheet, an electrical Zn—Ni alloy-coated steel sheet, and an electrical Zn—Fe
Has excellent plating adhesion to alloy plated steel sheets.
【００５７】[0057]
【表１】 [Table 1]
【００５８】[0058]
【表２】 [Table 2]
【００５９】[0059]
【表３】 [Table 3]
【００６０】[0060]
【表４】 [Table 4]
【００６１】[0061]
【発明の効果】本発明によれば、従来問題となっていた
溶融亜鉛めっき鋼板のスポット溶接性の問題を解決し、
スポット溶接性およびめっき密着性に優れた溶融亜鉛め
っき鋼板を提供することが可能となった。According to the present invention, the problem of spot weldability of a galvanized steel sheet, which has been a problem in the past, is solved.
It has become possible to provide a hot-dip galvanized steel sheet having excellent spot weldability and plating adhesion.
【図１】スポット溶接時の溶接点におけるめっき層の溶
融状態および素地鋼板同士の当接状態を示す縦断面図
(a) 並びに溶融亜鉛めっき層の層構造を示す縦断面図
(b)である。FIG. 1 is a longitudinal sectional view showing a molten state of a plating layer and a contact state between base steel plates at a welding point during spot welding.
(a) and a vertical sectional view showing the layer structure of the hot-dip galvanized layer
(b).
【符号の説明】 １ 素地鋼板（素材鋼板） ２ 溶融亜鉛めっき層（：めっき層） ３ 溶融した亜鉛 ４ 電極（溶接電極） ５ 隙間 10 Fe−Al金属間化合物（：Fe−Al合金層） 11 Fe−Zn金属間化合物（：Fe−Zn合金層） 12 η相（：Zn層） d1 スポット溶接時の両素地鋼板当接部の直径 d2 スポット溶接時の通電部の直径[Description of Signs] 1 Base steel sheet (base steel sheet) 2 Hot-dip galvanized layer (: plated layer) 3 Melted zinc 4 Electrode (welding electrode) 5 Gap 10 Fe-Al intermetallic compound (: Fe-Al alloy layer) 11 Fe-Zn intermetallic compound (: Fe-Zn alloy layer) 12 η phase (: Zn layer) d 1 Diameter of abutting part on both base steel plates during spot welding d 2 Diameter of conducting part during spot welding
───────────────────────────────────────────────────── フロントページの続き (72)発明者 加藤 千昭 千葉県千葉市中央区川崎町１番地 川崎製 鉄株式会社技術研究所内 (72)発明者 池田 倫正 千葉県千葉市中央区川崎町１番地 川崎製 鉄株式会社技術研究所内 (72)発明者 石井 和秀 千葉県千葉市中央区川崎町１番地 川崎製 鉄株式会社技術研究所内 Ｆターム(参考） 4K027 AA02 AA05 AA22 AB13 AB44 AC52 AE03 AE11 AE21 AE23 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Chiaki Kato 1 Kawasaki-cho, Chuo-ku, Chiba City, Chiba Prefecture Inside the Technical Research Institute of Kawasaki Steel Co., Ltd. Kazuhide Ishii, Inventor Kazuhide Ishii 1 Kawasaki-cho, Chuo-ku, Chiba City, Chiba Prefecture F-term (reference) 4K027 AA02 AA05 AA22 AB13 AB44 AC52 AE03 AE11 AE21 AE23
Claims (7)
a) 、めっき付着単位面積当たりのめっき付着量：Ｗ(g/
m2)およびめっき付着単位面積当たりのめっき層中の総A
l量：Ｘ(g/m2)が下記式(1) および(2) を満足すること
を特徴とするスポット溶接性に優れた溶融亜鉛めっき鋼
板。 記 0.15≦〔YS／（５×Ｗ）〕−〔Ｘ／２〕………(1) 0.10≦Ｘ≦0.50 …………………………………(2)1. Yield stress of hot-dip galvanized steel sheet: YS (MP
a), Plating weight per unit area of plating: W (g /
m 2 ) and total A in the plating layer per unit area of plating adhesion
l: A hot-dip galvanized steel sheet having excellent spot weldability, wherein X (g / m 2 ) satisfies the following formulas (1) and (2). 0.15 ≦ [YS / (5 × W)] − [X / 2] (1) 0.10 ≦ X ≦ 0.50 ……………… (2)
a) 、めっき付着単位面積当たりのめっき付着量：Ｗ(g/
m2)、めっき付着単位面積当たりのめっき層中の総Al
量：Ｘ(g/m2)、および、めっき／鋼板界面に存在するFe
−Al金属間化合物中のAl量を除いためっき付着単位面積
当たりのめっき層中のAl量：Ｙ(g/m2)が下記式(3) およ
び(4) を満足することを特徴とするスポット溶接性に優
れた溶融亜鉛めっき鋼板。 記 0.30 ≦〔YS／（５×Ｗ）〕−〔Ｙ／２〕……(3) 0.10 ≦Ｘ≦0.50 ………………………………(4)2. Yield stress of hot-dip galvanized steel sheet: YS (MP
a), Plating weight per unit area of plating: W (g /
m 2 ), total Al in the plating layer per unit area of plating adhesion
Amount: X (g / m 2 ) and Fe present at the plating / steel interface
-Characterized in that the amount of Al in the plating layer per unit area of plating excluding the amount of Al in the Al intermetallic compound: Y (g / m 2 ) satisfies the following formulas (3) and (4): Hot-dip galvanized steel sheet with excellent spot weldability. 0.30 ≤ [YS / (5 x W)]-[Y / 2] (3) 0.10 ≤ X ≤ 0.50 ............ (4)
Snの合計量が、0.02mass％以下であることを特徴とする
請求項１または２記載のスポット溶接性に優れた溶融亜
鉛めっき鋼板。3. Pb, Sb, Bi, As, Cd and Pb in a plating layer.
The hot-dip galvanized steel sheet having excellent spot weldability according to claim 1 or 2, wherein the total amount of Sn is 0.02 mass% or less.
／またはＰ：0.010〜0.050 mass％を含有する請求項１
〜３のいずれかに記載のスポット溶接性に優れた溶融亜
鉛めっき鋼板。4. The steel sheet according to claim 1, wherein B: 1 to 20 mass ppm and / or P: 0.010 to 0.050 mass%.
4. A hot-dip galvanized steel sheet having excellent spot weldability according to any one of Items 1 to 3.
上げてめっき付着量制御のためのガスワイピングを行う
溶融亜鉛めっき鋼板の製造方法において、溶融亜鉛めっ
き浴中の溶解Al濃度：ＮAl（mass％）およびガスワイピ
ング後のめっき付着単位面積当たりのめっき付着量：Ｗ
(g/m2)が下記式(5) を満足する条件下で鋼板に溶融亜鉛
めっきを施すことを特徴とするスポット溶接性に優れた
溶融亜鉛めっき鋼板の製造方法。 記 0.12≦ＮAl≦YS／（10×Ｗ）……………………(5) 上記式(5) 中、 YS：得られる溶融亜鉛めっき鋼板の降伏応力(MPa) を示す。After immersed 5. steel sheet hot-dip galvanizing bath, in the manufacturing method of the galvanized steel sheet to perform gas wiping for coating weight control by pulling, dissolved Al concentration in the molten zinc plating bath: N Al ( mass%) and the amount of plating applied per unit area of plating after gas wiping: W
A method for producing a hot-dip galvanized steel sheet having excellent spot weldability, wherein a hot-dip galvanized steel sheet is provided under conditions where (g / m 2 ) satisfies the following formula (5). 0.12 ≦ N Al ≦ YS / (10 × W) (5) In the above formula (5), YS represents the yield stress (MPa) of the obtained galvanized steel sheet.
CdおよびSnの濃度の合計量が、0.02mass％以下であるこ
とを特徴とする請求項５記載のスポット溶接性に優れた
溶融亜鉛めっき鋼板の製造方法。6. Pb, Sb, Bi, As, in a hot-dip galvanizing bath.
The method for producing a hot-dip galvanized steel sheet excellent in spot weldability according to claim 5, wherein the total amount of the concentrations of Cd and Sn is 0.02 mass% or less.
／またはＰ：0.010〜0.050 mass％を含有する請求項５
または６に記載のスポット溶接性に優れた溶融亜鉛めっ
き鋼板の製造方法。7. The steel sheet according to claim 5, wherein B: 1 to 20 mass ppm and / or P: 0.010 to 0.050 mass%.
Or the method for producing a galvanized steel sheet having excellent spot weldability according to 6.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001305610A JP3646685B2 (en) | 2000-09-29 | 2001-10-01 | Hot-dip galvanized steel sheet excellent in spot weldability and its manufacturing method |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000301527 | 2000-09-29 | ||
| JP2000-301527 | 2000-09-29 | ||
| JP2001305610A JP3646685B2 (en) | 2000-09-29 | 2001-10-01 | Hot-dip galvanized steel sheet excellent in spot weldability and its manufacturing method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2002173755A true JP2002173755A (en) | 2002-06-21 |
| JP3646685B2 JP3646685B2 (en) | 2005-05-11 |
Family
ID=26601311
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2001305610A Expired - Fee Related JP3646685B2 (en) | 2000-09-29 | 2001-10-01 | Hot-dip galvanized steel sheet excellent in spot weldability and its manufacturing method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3646685B2 (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2004315965A (en) * | 2003-03-28 | 2004-11-11 | Jfe Steel Kk | Hot dip galvanized steel sheet having excellent spot weldability and slidability on press working, and production method therefor |
| JP2009256703A (en) * | 2008-04-14 | 2009-11-05 | Nippon Steel Corp | Highly corrosion-resistant hot dip galvanized steel |
| JP2010070851A (en) * | 2008-08-21 | 2010-04-02 | Kawada Kogyo Kk | Hot-dip galvanized member superior in coatability by thermal spraying |
| KR20150060904A (en) * | 2012-10-31 | 2015-06-03 | 제이에프이 스틸 가부시키가이샤 | Hot-dip galvanized steel sheet |
-
2001
- 2001-10-01 JP JP2001305610A patent/JP3646685B2/en not_active Expired - Fee Related
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2004315965A (en) * | 2003-03-28 | 2004-11-11 | Jfe Steel Kk | Hot dip galvanized steel sheet having excellent spot weldability and slidability on press working, and production method therefor |
| JP2009256703A (en) * | 2008-04-14 | 2009-11-05 | Nippon Steel Corp | Highly corrosion-resistant hot dip galvanized steel |
| JP2010070851A (en) * | 2008-08-21 | 2010-04-02 | Kawada Kogyo Kk | Hot-dip galvanized member superior in coatability by thermal spraying |
| KR20150060904A (en) * | 2012-10-31 | 2015-06-03 | 제이에프이 스틸 가부시키가이샤 | Hot-dip galvanized steel sheet |
| KR101718469B1 (en) * | 2012-10-31 | 2017-03-21 | 제이에프이 스틸 가부시키가이샤 | Galvanized steel sheet |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3646685B2 (en) | 2005-05-11 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| KR100888908B1 (en) | Surface treated steel plate and method for production thereof | |
| JP3990539B2 (en) | High-strength hot-dip galvanized steel sheet and high-strength galvannealed steel sheet excellent in plating adhesion and press formability and method for producing the same | |
| CN102011053B (en) | High-yield-ratio high-strength thin steel sheet excelling in weldability and ductility and manufacturing method thereof | |
| JP3809074B2 (en) | High-strength hot-dip galvanized steel sheet with excellent plating adhesion and press formability and method for producing the same | |
| JP7358542B2 (en) | Method for manufacturing alloyed hot-dip galvanized steel sheet resistant to liquid metal embrittlement | |
| JP2016084543A (en) | Hot-dip plating steel sheet excellent in plating adhesion and method for manufacturing the same | |
| JP5417797B2 (en) | High strength hot dip galvanized steel sheet and method for producing the same | |
| JP2610948B2 (en) | Manufacturing method of galvannealed steel sheet with excellent spot weldability | |
| JP2011208264A (en) | Vehicle chassis member excellent in corrosion resistance and method of manufacturing the same | |
| EP0434874B1 (en) | Galvannealed steel sheet having improved spot-weldability | |
| JP3600804B2 (en) | Hot-dip galvanized steel sheet with excellent formability | |
| KR20140131203A (en) | Method for manufacturing high-strength hot-dip zinc surface quality, plating adhesion and superior weldability galvanized steel sheet | |
| JP2002309358A (en) | Galvannealed steel sheet with excellent workability | |
| JP3501748B2 (en) | High-strength hot-dip galvanized steel sheet with excellent workability and its manufacturing method | |
| JP3646685B2 (en) | Hot-dip galvanized steel sheet excellent in spot weldability and its manufacturing method | |
| JP4150277B2 (en) | High strength galvannealed steel sheet excellent in press formability and method for producing the same | |
| JP4947565B2 (en) | A method for producing a high-strength hot-dip galvanized steel sheet excellent in plating adhesion and press formability. | |
| JP4718682B2 (en) | High-strength galvannealed steel sheet and high-strength hot-dip galvanized steel sheet excellent in plating adhesion and press formability and manufacturing method thereof | |
| JP2002241916A (en) | Plated steel sheet having excellent corrosion resistance, workability and weldability and production method therefor | |
| CN110088349B (en) | High manganese hot-dip aluminum-plated steel sheet having excellent sacrificial corrosion protection and plating properties, and method for producing same | |
| JP2002180225A (en) | Plated steel sheet having excellent corrosion resistance and workability | |
| JP7506350B2 (en) | Steel welded parts | |
| JP3694480B2 (en) | Method for producing high tension molten Zn-Mg-Al plated steel sheet | |
| JPH0565612A (en) | Hot-dip galvanizing method for si-containing steel sheet | |
| JP3531595B2 (en) | Hot-dip galvanized steel sheet excellent in spot weldability and press formability and method for producing the same |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20040929 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20041012 |
|
| 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: 20050118 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20050131 |
|
| R150 | Certificate of patent or registration of utility model |
Free format text: JAPANESE INTERMEDIATE CODE: R150 Ref document number: 3646685 Country of ref document: JP Free format text: JAPANESE INTERMEDIATE CODE: R150 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20080218 Year of fee payment: 3 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20090218 Year of fee payment: 4 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20100218 Year of fee payment: 5 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20100218 Year of fee payment: 5 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20110218 Year of fee payment: 6 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20120218 Year of fee payment: 7 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20120218 Year of fee payment: 7 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20130218 Year of fee payment: 8 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20130218 Year of fee payment: 8 |
|
| LAPS | Cancellation because of no payment of annual fees |