JPH0533111A - Galvannealed steel sheet - Google Patents
Galvannealed steel sheetInfo
- Publication number
- JPH0533111A JPH0533111A JP18892091A JP18892091A JPH0533111A JP H0533111 A JPH0533111 A JP H0533111A JP 18892091 A JP18892091 A JP 18892091A JP 18892091 A JP18892091 A JP 18892091A JP H0533111 A JPH0533111 A JP H0533111A
- Authority
- JP
- Japan
- Prior art keywords
- steel sheet
- steel
- plating
- layer
- interface
- 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]
【産業上の利用分野】本発明は、鋼板とその上に設けた
めっき層とから構成される一種の複合材料である合金化
溶融亜鉛めっき鋼板に関し、より具体的には、めっき皮
膜と鋼板基材との密着性に優れた合金化溶融亜鉛めっき
鋼板、特に家電用塗装鋼板、自動車用鋼板として好適な
合金化溶融亜鉛めっき鋼板に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an alloyed hot-dip galvanized steel sheet which is a kind of composite material composed of a steel sheet and a plating layer provided thereon, and more specifically, a plating film and a steel sheet base. TECHNICAL FIELD The present invention relates to an alloyed hot dip galvanized steel sheet having excellent adhesion to a material, particularly a coated steel sheet for household appliances, and an alloyed hot dip galvanized steel sheet suitable as an automobile steel sheet.
【０００２】[0002]
【従来の技術】近年、家電、建材、および自動車の産業
分野においては亜鉛系のめっき鋼板が大量に使用されて
いるが、とりわけ経済性とその防錆機能、さらには塗装
後の耐食性、加工性等の性能の点で合金化溶融亜鉛めっ
き鋼板が広く用いられようになってきている。合金化溶
融亜鉛めっき鋼板は、鋼板基材にめっき層を合金化して
複合化した一種の複合材料であり、通常、連続的に溶融
亜鉛めっきした鋼板を熱処理炉で 500〜600 ℃の材料温
度に３〜30s 加熱することによりFe−Zn合金めっき層を
形成せしめて製造される。その場合、鋼板は、溶融めっ
き前に連続炉において予熱されH2＋N2の保護雰囲気中、
材料に応じた焼鈍温度条件で還元焼鈍され、次いでめっ
き浴温度前後に冷却され、しかる後溶融亜鉛めっきが施
される。保護雰囲気の露点は−35℃から−20℃の範囲に
ありこれよりも高い露点では不めっきが生じる場合があ
る。不めっきの発生は焼鈍過程で生じる鋼板表面のSi、
Mn等の酸化物が原因である。2. Description of the Related Art In recent years, a large amount of zinc-based plated steel sheets have been used in the industrial fields of home appliances, building materials, and automobiles. Especially, they are economical and their rust preventive function, and corrosion resistance and workability after painting. In terms of performance such as the above, galvannealed steel sheets have been widely used. A galvannealed steel sheet is a kind of composite material in which a steel sheet base material is alloyed with a plating layer to form a composite.Usually, hot-dip galvanized steel sheet is heated in a heat treatment furnace to a material temperature of 500 to 600 ° C. It is manufactured by forming a Fe-Zn alloy plating layer by heating for 3 to 30 seconds. In that case, the steel sheet is preheated in a continuous furnace before hot dip coating in a protective atmosphere of H 2 + N 2 ,
It is subjected to reduction annealing under annealing temperature conditions suitable for the material, then cooled to around the plating bath temperature, and then subjected to hot dip galvanizing. The dew point of the protective atmosphere is in the range of -35 ° C to -20 ° C, and higher dew points may cause non-plating. The occurrence of non-plating is caused by Si on the steel plate surface during the annealing process,
The cause is oxides such as Mn.
【０００３】合金化溶融亜鉛めっき鋼板のめっき層はFe
−Znの金属間化合物より成り、一般にその平均Fe濃度は
８〜12wt％である。そのめっき付着量は通常片面当り25
〜70g/m2であり、これより薄いものは通常の手段では製
造することが難しく、またこの範囲を上回る厚いものは
めっき層の耐パウダリング性を確保することが困難であ
るので一般には製造されていない。めっき皮膜中には通
常0.12〜0.2 ％前後のAlが含有されることが多い。これ
は合金化溶融亜鉛めっき鋼板と同一設備で製造される通
常の溶融亜鉛めっき鋼板のめっき／鋼界面における合金
層の生成を抑制してめっき層の加工性を保持するために
添加されるAlが不可避的に混入することもあるが、通常
は、合金化溶融亜鉛めっき層の耐パウダリング性を確保
し、かつ溶融めっき時のドロスの発生を抑制するうえか
らもめっき浴中に0.08〜0.11％程度のAlを混入させるこ
とがむしろ適当であると考えられているからである。Al
はめっき時にめっき層中に富化する傾向があるため、そ
のようなAl含有めっき浴でめっきすればめっき層中のAl
濃度は0.12〜0.2 ％の範囲となるのである。The coating layer of the galvannealed steel sheet is Fe
It consists of an intermetallic compound of --Zn, and generally has an average Fe concentration of 8 to 12 wt%. The plating amount is usually 25 per side
~ 70 g / m 2 , thinner than this is difficult to produce by ordinary means, thicker than this range is difficult to ensure the powdering resistance of the plating layer is generally produced. It has not been. The plating film usually contains about 0.12 to 0.2% of Al. This is because Al added to suppress the formation of an alloy layer at the plating / steel interface of a normal hot-dip galvanized steel sheet produced by the same equipment as the alloyed hot-dip galvanized steel sheet and to maintain the workability of the galvanized layer. It may inevitably be mixed, but usually 0.08 to 0.11% in the plating bath in order to secure the powdering resistance of the galvannealed layer and to suppress the generation of dross during hot dipping. This is because it is considered appropriate to mix Al in a certain amount. Al
Tends to be enriched in the plating layer during plating.
The concentration is in the range of 0.12 to 0.2%.
【０００４】一方、合金化溶融亜鉛めっき鋼板の鋼板素
材としては従来低炭素Alキルド鋼が用いられることが多
かったが、近年その用途の拡大に伴って深絞り性が要求
されることが多くなったためいわゆるIF鋼と呼ばれる極
低炭素鋼が使用される場合も増加している。このIF鋼(i
nterstitial-free 鋼) は、不可避的なＮ、Ｃ等の侵入
型固溶元素をTiもしくはNb等の合金元素で固定した材料
であり、非時効性で加工性の高い素材である。かかるIF
鋼の成分として通常Ｃ≦0.003 ％、Si≦0.04％、Mn:0.1
2 〜0.30％、Ｐ:0.01 〜0.02％、Ｓ:0.008〜0.02％、Ｎ
≦0.04％、Al:0.02 〜0.05％、Ti:0.02 〜0.06％、Nb≦
0.015 ％の素材が広く採用されている。なお、Nbに関し
ては添加されない場合もあり、またフェライト粒界の脆
化防止のために20ppm 以下のＢがさらに添加される場合
もある。On the other hand, low carbon Al-killed steel has often been used as a steel sheet material for the galvannealed steel sheet, but in recent years, deep drawability is often required as its application is expanded. Therefore, the number of cases where ultra-low carbon steel called IF steel is used is increasing. This IF steel (i
(nterstitial-free steel) is an inevitable interstitial solid solution element such as N or C fixed with an alloy element such as Ti or Nb, and is a non-aging and highly workable material. Such IF
As a steel component, usually C ≦ 0.003%, Si ≦ 0.04%, Mn: 0.1
2 to 0.30%, P: 0.01 to 0.02%, S: 0.008 to 0.02%, N
≤0.04%, Al: 0.02-0.05%, Ti: 0.02-0.06%, Nb≤
0.015% material is widely used. Note that Nb may not be added, and 20 ppm or less of B may be further added to prevent embrittlement of ferrite grain boundaries.
【０００５】このように、合金化溶融亜鉛めっき鋼板は
広い用途を有するが、金属間化合物系の皮膜を有するた
めに、めっき／鋼界面の密着性が低いという欠点があ
る。すなわち、Ni−Zn、Fe−Zn等の電気めっき手段によ
る合金めっきも含めて皮膜に変形能のない場合、めっき
皮膜と鋼との界面に剪断力が作用した場合、界面で剥離
が生じやすいという欠点がある。結果的には、特に塗装
した後の衝撃的な変形や、剪断等の加工で剥離を生じや
すいほか、接着材で接合した場合に鋼板／めっき界面で
剥離してしまうことがある。かかる問題点について電気
めっき系の場合には、あらかじめ鋼板表面にNi濃度の高
いNi−Zn層の薄層を施すなどの適当な前処理手段で解決
できることが知られているが、合金化溶融亜鉛めっき鋼
板に関しては適当な手段がほとんどないのが実状であ
る。As described above, the alloyed hot-dip galvanized steel sheet has a wide range of uses, but it has a drawback that the plating / steel interface has low adhesion because it has an intermetallic compound coating. That is, Ni-Zn, Fe-Zn and the like, if the coating is not deformable, including alloy plating by electroplating means, if a shearing force acts on the interface between the plated coating and steel, peeling is likely to occur at the interface. There are drawbacks. As a result, in particular, it is likely that peeling will occur due to shocking deformation after coating, processing such as shearing, and peeling may occur at the steel plate / plating interface when joining with an adhesive. It is known that such a problem can be solved by an appropriate pretreatment means such as applying a thin layer of a Ni-Zn layer having a high Ni concentration on the surface of a steel sheet in advance in the case of electroplating system. The reality is that there are few suitable means for plated steel sheets.
【０００６】[0006]
【発明が解決しようとする課題】従来の合金化溶融亜鉛
めっき鋼板では、めっき／鋼界面の密着力が非常に小さ
く、そのため各種の過酷な変形や衝撃 (特に塗装後の)
を受けた場合にそれに耐えられない。したがって、本発
明の目的は、めっき／鋼界面の密着力を大幅に向上させ
た合金化溶融亜鉛めっき鋼板を提供することである。よ
り具体的には、本発明の目的は、めっき／鋼界面の密着
力の指標である剥離面積率30％以下、かつ成形性の指標
としての機械特性値として、伸び45％以上、γ値1.5 以
上である合金化溶融亜鉛めっき鋼板を提供することであ
る。In the conventional galvannealed steel sheet, the adhesion force at the plating / steel interface is very small, so that various severe deformations and impacts (especially after coating)
I cannot bear it if I receive it. Therefore, an object of the present invention is to provide an alloyed hot-dip galvanized steel sheet having a significantly improved adhesion at the plating / steel interface. More specifically, the object of the present invention is to provide a peeling area ratio of 30% or less, which is an index of the adhesion force at the plating / steel interface, and a mechanical property value as an index of formability, an elongation of 45% or more and a γ value of 1.5. An object of the present invention is to provide an alloyed hot-dip galvanized steel sheet.
【０００７】[0007]
【課題を解決するための手段】かかるめっき／鋼界面の
剥離の問題は、界面の幾何学的な形状、めっき層および
基板の機械的な性質や物理常数 (例えば弾性率) 等によ
るばかりでなく、真の界面密着強度によって最も強く支
配されると考えられる。従って、界面の密着性に優れた
鋼板を得るためにはめっき層の改質、めっき／鋼界面の
幾何学的形状の適正化、鋼板素材の適正化等の観点から
ばかりでなく真の界面密着度の改善のための対策が必要
となる。そこで、かかる観点から本発明者らが、合金化
溶融亜鉛めっき鋼板のめっき／鋼界面の密着力改善に関
して鋭意検討した結果、極低炭素鋼において基板表面の
結晶方位を制御しα｛111 ｝方位およびこの近傍方位面
を抑制し鋼板表面にα[001] 晶帯面を増加させることが
めっき層／鋼板界面の密着力向上に有効なことを見い出
し、本発明を完成した。The problem of peeling at the plating / steel interface is not limited to the geometrical shape of the interface, the mechanical properties of the plating layer and the substrate, the physical constant (eg, elastic modulus), and the like. , And is believed to be most strongly governed by the true interfacial adhesion strength. Therefore, in order to obtain a steel sheet with excellent interfacial adhesion, not only from the viewpoint of modifying the plating layer, optimizing the geometric shape of the plating / steel interface, optimizing the steel sheet material, etc. It is necessary to take measures to improve the degree. From this point of view, the inventors of the present invention have earnestly studied the improvement of the adhesion force at the plating / steel interface of the galvannealed steel sheet, and as a result, the crystal orientation of the substrate surface in the ultra-low carbon steel is controlled and The present invention has been completed by discovering that suppressing the azimuth plane in the vicinity and increasing the α [001] crystal band plane on the surface of the steel sheet is effective in improving the adhesion at the plating layer / steel sheet interface.
【０００８】ここに、本発明は、極低炭素鋼板とその上
に被覆されためっき層から構成された合金化溶融亜鉛め
っき鋼板であって、該極低炭素鋼板が、Ｃ≦0.008 重量
％、Ｐ≦0.03重量％、かつTi≧0.02重量％またはTi＋Nb
≧0.02重量％であり、さらに該極低炭素鋼板の表層のフ
ェライト方位が、Ｘ線回折積分強度比で Ｉ(222) ／Ｉ(200) ≦ 3.8 鋼板内部のフェライト方位が、同じくＸ線回折積分強度
比で Ｉ(222) ／Ｉ(200) ≧ 12 であり、前記めっき層が、重量割合で、Al／Zn≧0.15
％、Fe／(Fe+Zn): 8〜15％であることを特徴とする合金
化溶融亜鉛めっき鋼板である。The present invention is an alloyed hot-dip galvanized steel sheet comprising an ultra-low carbon steel sheet and a plating layer coated thereon, wherein the ultra-low carbon steel sheet has C ≦ 0.008% by weight, P ≦ 0.03% by weight and Ti ≧ 0.02% by weight or Ti + Nb
≧ 0.02% by weight, and the ferrite orientation of the surface layer of the ultra-low carbon steel sheet is I (222) / I (200) ≦ 3.8 in terms of X-ray diffraction integrated intensity ratio. The strength ratio is I (222) / I (200) ≧ 12, and the plating layer has a weight ratio of Al / Zn ≧ 0.15.
%, Fe / (Fe + Zn): 8 to 15%, which is an alloyed hot-dip galvanized steel sheet.
【０００９】[0009]
【作用】このように、本発明によれば、上述の表面配向
性を有する鋼板を0.10〜0.2 ％AlのZnめっき浴で溶融め
っきし、さらに合金化処理を施すことによりめっき／鋼
界面の密着力が格段に向上するのである。このようなす
ぐれた作用効果が発揮される機構については現在必ずし
も明確でないが、以下のように考えられる。つまり、鋼
板と合金化溶融亜鉛めっき層の密着力が向上するために
は、α−Fe表層が侵食されFe濃度が過剰のГ相ないしは
α−FeのZn固溶体に近い組成の薄層が形成されることが
必要と考えられる。ところが、α−Feの面方位により溶
融亜鉛との反応性が異なり、α｛111 ｝近傍面ではかか
る領域が形成されにくいのに対して、α[001] 晶帯の近
傍面では溶融亜鉛との反応でかかる領域が形成され易
い。またZn中のAl濃度が低い場合はГ相は形成される
が、上記に相当する薄層は形成されにくい。As described above, according to the present invention, the steel sheet having the above-mentioned surface orientation is hot-dipped with a Zn plating bath of 0.10 to 0.2% Al, and further subjected to an alloying treatment to achieve adhesion at the plating / steel interface. The power is greatly improved. The mechanism by which such excellent action and effect are exhibited is not always clear at present, but it is considered as follows. That is, in order to improve the adhesion between the steel sheet and the galvannealed layer, the α-Fe surface layer is eroded to form a Γ phase with an excessive Fe concentration or a thin layer having a composition close to that of a Zn solid solution of α-Fe. It is considered necessary to However, the reactivity with molten zinc differs depending on the plane orientation of α-Fe, and such a region is less likely to be formed on the surface near α {111}. Such a region is easily formed by the reaction. When the Al concentration in Zn is low, the Γ phase is formed, but the thin layer corresponding to the above is hard to be formed.
【００１０】また、かかる薄層の形成は、鋼の純度にも
依存し、極低炭素鋼等では形成されやすいが固溶炭素の
存在する鋼やＰ添加鋼では生じにくい。したがって、特
定の組成をもった鋼に表層のα−Feの配向性を制御し比
較的Al濃度の高いZnめっき浴でめっきし、合金化処理す
ることで格段に界面密着性に優れた合金化溶融亜鉛めっ
き鋼板を提供することができる。かくして、極低炭素鋼
の表層のα｛111 ｝の発達を抑制し、α｛100 ｝、α
｛110 ｝の成長を促進することで望ましいめっき密着性
が得られるが、極低炭素鋼の優れた機械的特性を満たす
には鋼板内部でα｛111 ｝を十分発達させる必要があ
る。このように鋼板の表層のみでα｛111 ｝の発達を抑
制し、内部でα｛111｝の発達を促進する方法の一つと
して具体的には、焼鈍前の鋼板にアルカリ水溶液を塗布
した後、焼鈍することで可能となる。なお、この点、従
来はこのような考えはなく、脱脂にアルカリ液が用いら
れるが水洗後焼鈍されてきた。The formation of such a thin layer also depends on the purity of the steel, and is easily formed in ultra-low carbon steel or the like, but is less likely to occur in steel containing solute carbon or P-added steel. Therefore, by controlling the orientation of α-Fe in the surface layer on steel with a specific composition, plating with a Zn plating bath with a relatively high Al concentration, and alloying it, alloying with outstanding interfacial adhesion is achieved. A hot-dip galvanized steel sheet can be provided. Thus, the development of α {111} on the surface of ultra low carbon steel is suppressed, and α {100}, α
Although desirable plating adhesion can be obtained by promoting the growth of {110}, α {111} must be sufficiently developed inside the steel plate to satisfy the excellent mechanical properties of the ultra-low carbon steel. In this way, as one of the methods of suppressing the development of α {111} only in the surface layer of the steel sheet and promoting the development of α {111} inside, specifically, after applying an alkaline aqueous solution to the steel sheet before annealing, It becomes possible by annealing. Regarding this point, conventionally, there is no such idea, and an alkaline solution is used for degreasing, but it has been annealed after washing with water.
【００１１】次に、本発明において上述のような限定を
なした理由を説明する。本発明においては基板となる鋼
板は極低炭素IF鋼であり、そのためには鋼成分として重
量比でＣ＜0.008 ％、Ｐ＜0.03％、Ti≧0.02％またはTi
＋Nb≧0.02％を満たすことが要求される。Next, the reason why the above-mentioned limitation is made in the present invention will be explained. In the present invention, the steel plate that serves as the substrate is an ultra-low carbon IF steel, and for that purpose, C <0.008%, P <0.03%, Ti ≧ 0.02% or Ti is used as a steel component by weight ratio.
It is required to satisfy + Nb ≧ 0.02%.
【００１２】Ｃはその量が多いと固溶体をつくりやすく
成形性が低下する上、Fe濃度が過剰のΓ相ないしα−Fe
のZn固溶体に近い組成の薄層の形成を妨げる。ＣはTiや
Nbで固定することができるがＣの濃度が増加すると必要
なTiもしくはNbの濃度が増加しコストアップにつなが
る。そのため上限は0.008 ％とする。If the amount of C is large, it tends to form a solid solution and the formability is deteriorated, and in addition, the Γ phase or α-Fe having an excessive Fe concentration is used.
Prevents the formation of a thin layer with a composition close to that of Zn solid solution. C is Ti or
It can be fixed with Nb, but if the concentration of C increases, the required concentration of Ti or Nb increases, which leads to an increase in cost. Therefore, the upper limit is 0.008%.
【００１３】ＰはFe濃度が過剰のΓ相ないしはα−Feの
Zn固溶体に近い組成の薄層の形成を妨げる作用があり、
Ti添加鋼あるいはTi・Nb添加鋼においては合金化溶融亜
鉛めっき皮膜と鋼の界面の密着性を低下させる。さらに
ＰはTiと結合してTiのＣ固定を妨げる。このような点か
ら上限を0.03％とする。P is a Γ phase or α-Fe with an excessive Fe concentration.
Has the effect of preventing the formation of a thin layer having a composition close to that of a Zn solid solution,
In Ti-added steel or Ti / Nb-added steel, the adhesion at the interface between the galvannealed coating and the steel is reduced. Further, P binds to Ti and prevents C fixation of Ti. From this point, the upper limit is 0.03%.
【００１４】Ti、もしくはTi＋NbはＣを固定しIF鋼とす
るために必要であるが、Ｎ、Ｓ、Ｐとも結合するため通
常0.02％以上必要である。特に上限は規定されないが、
一般には 0.2％以下である。Ti or Ti + Nb is necessary to fix C to form IF steel, but it is usually required to be 0.02% or more because it is also combined with N, S and P. No upper limit is specified,
Generally, it is 0.2% or less.
【００１５】本発明に対して直接の影響はないので特に
規定はしないが、本発明の好適態様によれば、他の合金
元素として、Si≦0.04％、Mn≦0.80％、Ｓ≦0.02％、Ｎ
≦0.05％、およびAl≦0.05％の少なくとも一種が必要に
応じて共存するものとする。またフェライト粒界の脆化
防止のために20ppm 以下のＢがさらに添加される場合も
ある。Although there is no direct influence on the present invention, no particular definition is made, but according to the preferred embodiment of the present invention, as other alloying elements, Si ≦ 0.04%, Mn ≦ 0.80%, S ≦ 0.02%, N
At least one of ≦ 0.05% and Al ≦ 0.05% coexists as necessary. Further, B may be further added in an amount of 20 ppm or less in order to prevent embrittlement of ferrite grain boundaries.
【００１６】したがって、より特定的には、本発明の対
象とする鋼板は、次の鋼組成を有するものである。Ｃ:
0.008％以下、Si:0.04 ％以下、Mn:0.80 ％以下、Ｐ:0.
03 ％以下、Ｓ:0.02 ％以下、Ti:0.02 〜0.2 ％、ただ
し、Nbを含有する場合、Ti+Nb:0.02〜0.2 ％、Ｎ:0.05
％以下、Al:0.05 ％以下、所望によりＢ:20 ppm以下。Therefore, more specifically, the steel sheet targeted by the present invention has the following steel composition. C:
0.008% or less, Si: 0.04% or less, Mn: 0.80% or less, P: 0.
03% or less, S: 0.02% or less, Ti: 0.02 to 0.2%, but when Nb is contained, Ti + Nb: 0.02 to 0.2%, N: 0.05
% Or less, Al: 0.05% or less, and optionally B: 20 ppm or less.
【００１７】次に、鋼板表層のフェライト方位がＸ線回
折積分強度比でＩ(222) ／Ｉ(200)≦3.8 、鋼板内部の
フェライト方位がＩ(222) ／Ｉ(200) ≧12を満たす必要
がある。Next, the ferrite orientation of the surface layer of the steel sheet satisfies I (222) / I (200) ≤3.8 by the X-ray diffraction integrated intensity ratio, and the ferrite orientation inside the steel sheet satisfies I (222) / I (200) ≥12. There is a need.
【００１８】ただし、本明細書において、上記Ｘ線回折
強度は、Mo管球を用い加速電圧30kv、電流100mA の条件
で測定するものとしＩ(222) 、Ｉ(200) は下記の式によ
り基準化した値を用いるものとする。 Ｉ(hkl) ＝ [I(hkl)m −Ｉb]／Ｉ(hkl)s Ｉ(hkl) : 規準化された(hkl) 面の積分強度 Ｉ(hkl)m : (hkl) 面の強度カウント Ｉb : バックグラウンドカウント Ｉ(hkl)s : 還元Fe標準試料の(hkl) 面の積分強度 また鋼板表面層の方位はめっき層をインヒビター含有酸
液で除去した状態で測定するものとし、鋼板内部の方位
は表面から板厚の1/4 を研磨除去した後測定するものと
する。In the present specification, however, the X-ray diffraction intensity is measured using a Mo tube under the conditions of an acceleration voltage of 30 kv and a current of 100 mA, and I (222) and I (200) are standardized according to the following equations. The converted value shall be used. I (hkl) = [I (hkl) m-Ib] / I (hkl) s I (hkl): Normalized integrated intensity of (hkl) plane I (hkl) m: (hkl) intensity count Ib : Background count I (hkl) s: Integrated strength of (hkl) plane of reduced Fe standard sample Also, the orientation of the steel sheet surface layer shall be measured with the plating layer removed with an acid solution containing an inhibitor. Shall be measured after polishing and removing 1/4 of the plate thickness from the surface.
【００１９】前述のように合金化溶融亜鉛めっき層と鋼
との界面の密着性を高めるためには鋼板表層のα｛100
｝、α｛110 ｝の成長を促進し、α｛111 ｝の発達を
抑制する必要がある。ところで、α｛100 ｝の発達とα
｛110 ｝の発達はほぼ比例関係にあるためα｛100 ｝と
α｛111 ｝の状態を規定すれば、フェライトの配向性を
記述できる。As described above, in order to enhance the adhesiveness at the interface between the galvannealed layer and the steel, α {100 of the surface layer of the steel sheet is used.
}, Α {110} growth must be promoted and α {111} development must be suppressed. By the way, the development of α {100} and α
Since the development of {110} is almost proportional, the orientation of ferrite can be described by defining the states of α {100} and α {111}.
【００２０】したがって、本発明では、α｛111 ｝とα
｛100｝のＸ線回折強度比Ｉ(222)／Ｉ(200) を採用す
る。α｛111 ｝はZnとの反応性が小さく、Fe濃度が過剰
のΓ相ないしはα−FeのZn固溶体に近い組成の薄層を形
成しにくいため、めっき／鋼界面の密着性にはあまり望
ましいものではない。むしろ界面の密着性の向上にはα
｛100 ｝、α｛110 ｝を発達させてZnとの反応を大きく
する必要がある。鋼板表層のフェライト方位が、Ｘ線回
折積分強度比で、Ｉ(222) ／Ｉ(200) ＞3.8 では望まし
い密着性は達成できない。一方、鋼板内部のフェライト
方位が、同じくＸ線回折積分強度比で、Ｉ(222) ／Ｉ(2
00) ＜12では鋼板内部の再結晶が不十分で満足な延性、
深絞り性を確保することはできない。Therefore, in the present invention, α {111} and α
The X-ray diffraction intensity ratio I (222) / I (200) of {100} is adopted. α {111} has a low reactivity with Zn, and it is difficult to form a Γ phase with an excessive Fe concentration or a thin layer having a composition close to that of a Zn solid solution of α-Fe, so it is very desirable for the adhesion at the plating / steel interface. Not a thing. Rather, to improve the adhesion of the interface, α
It is necessary to develop {100} and α {110} to increase the reaction with Zn. If the ferrite orientation of the surface layer of the steel sheet is I (222) / I (200)> 3.8 in terms of X-ray diffraction integrated intensity ratio, the desired adhesion cannot be achieved. On the other hand, the ferrite orientation inside the steel plate is I (222) / I (2
00) <12, the recrystallization inside the steel sheet is insufficient and satisfactory ductility,
Deep drawability cannot be ensured.
【００２１】このように、鋼板表面と内部とでＸ線回折
積分強度比を変えるには、前述のように鋼板表面にアル
カリを塗布する等の前処理を行うか、あるいは焼鈍雰囲
気の露点を変えることが好ましい。さらに鋼板上に形成
されためっき層が、重量割合で、Al／Zn≧0.15％、Fe／
(Fe+Zn) :8〜15％であることが要求される。上記めっき
層におけるAlは鋼板とめっき面の界面強度を向上させる
作用があり、特にα｛100 ｝、｛110 ｝面のめっき層と
の密着性を高める作用があると考えられるが、Al／Znが
0.15％未満では十分な密着性が確保されない。一方、上
記めっき層のFe濃度は高い方が「Fe濃度が過剰のΓ相な
いしはα−FeのZn固溶体に近い組成の薄層」の形成に寄
与し、鋼表面が侵食され密着性が向上するが、15％超で
はパウダリングしやすくなる。８％未満では未合金化亜
鉛が残存して溶接性の低下が起こる。望ましくはFe:9〜
11％である。As described above, in order to change the X-ray diffraction integrated intensity ratio between the surface of the steel sheet and the inside thereof, pretreatment such as applying an alkali to the surface of the steel sheet is performed as described above, or the dew point of the annealing atmosphere is changed. Preferably. Further, the plating layer formed on the steel sheet is, by weight ratio, Al / Zn ≧ 0.15%, Fe /
(Fe + Zn): Required to be 8 to 15%. Al in the plating layer has the function of improving the interfacial strength between the steel plate and the plating surface, and is particularly considered to have the function of increasing the adhesion between the plating layer on the α {100} and {110} planes. But
If it is less than 0.15%, sufficient adhesion cannot be secured. On the other hand, the higher Fe concentration of the plating layer contributes to the formation of "a thin layer having a composition close to that of a Γ phase or an α-Fe Zn solid solution having an excessive Fe concentration", and the steel surface is eroded to improve the adhesion. However, if it exceeds 15%, it becomes easier to powder. If it is less than 8%, unalloyed zinc remains and the weldability deteriorates. Desirably Fe: 9 ~
11%.
【００２２】ここに、本発明にかかる合金化溶融亜鉛め
っき鋼板の製造に際しては、所定の成分よりなる極低炭
素鋼スラブを、たとえば、通常の手段により熱間圧延、
酸洗、冷間圧延の各工程を経て得た鋼板を脱脂洗浄した
後、その鋼板表面に１％NaOH水溶液を塗布したまま乾燥
し、これを例えばO2濃度10ppm 以下、露点−40℃以下の
H2＋N2雰囲気中所定の再結晶温度で焼鈍し、しかる後、
溶融亜鉛めっきおよび合金化処理することにより得られ
る。めっき浴には通常0.08％以上のAlを添加する。めっ
き過程でAlがめっき層、特に鋼板／めっき界面に濃化す
るため、めっき後0.15％以上のAl濃度とすることができ
る。合金化処理は300 〜600 ℃で40h 〜2sで可能である
が: 特に450 〜530 ℃で200 〜5sで行うことが望まし
い。以上のような条件を満たす本発明にかかる合金化溶
融亜鉛めっき鋼板は鋼板表面の結晶配向性効果とめっき
層中のAl濃度の効果によりめっき層／鋼板界面の密着性
を著しく高めることができる。次に、本発明をその実施
例によって更に具体的に説明する。しかし、これはあく
まで例示であって、したがってこれにより本発明が不当
に制約されるものではない。In producing the alloyed hot-dip galvanized steel sheet according to the present invention, an ultra-low carbon steel slab having predetermined components is hot-rolled, for example, by a conventional means.
After degreasing and washing the steel sheet obtained through each step of pickling and cold rolling, the steel sheet surface is dried with a 1% NaOH aqueous solution applied, for example, with an O 2 concentration of 10 ppm or less and a dew point of −40 ° C. or less.
Anneal at a predetermined recrystallization temperature in an H 2 + N 2 atmosphere, and then
It is obtained by hot dip galvanizing and alloying treatment. Usually 0.08% or more of Al is added to the plating bath. Since Al is concentrated in the plating layer, particularly the steel plate / plating interface during the plating process, the Al concentration can be 0.15% or more after plating. The alloying treatment can be carried out at 300-600 ° C for 40h-2s: it is particularly preferred to carry out at 450-530 ° C for 200-5s. The alloyed hot-dip galvanized steel sheet according to the present invention satisfying the above conditions can remarkably enhance the adhesion at the plating layer / steel sheet interface due to the crystal orientation effect on the steel sheet surface and the effect of Al concentration in the plating layer. Next, the present invention will be described more specifically by way of its examples. However, this is merely an example, and thus the present invention is not unduly limited.
【００２３】[0023]
【実施例】表１に示す鋼組成を有する３種類の極低炭素
鋼冷延鋼板の未焼鈍材(板厚 0.8mmt)を250 ×100 mmに
裁断して供試鋼板とした。この鋼板を後述する表２に示
す各種方法で前処理した後、竪型溶融亜鉛めっき装置を
用いて溶融めっきを行った。鋼板は、この装置内で、露
点−22℃〜−50℃、酸素濃度１〜８ppm のN2＋26％H2の
雰囲気中750 〜850 ℃×60s の焼鈍処理を施し、次いで
460 ℃の鋼板温度に冷却の後、全Al濃度0.137 ％、全Fe
濃度0.020 ％の溶融亜鉛めっき浴中で溶融めっきを行っ
た。めっき時間は1sであり、ガスワイパーによりZn付着
量は約50g/m2(片面当り) に調整した。溶融亜鉛めっき
済みの試験片は500 ℃の塩浴中に18〜21s浸漬して合金
化処理を行った。[Examples] Three types of ultra-low carbon steel cold-rolled steel sheets having the steel compositions shown in Table 1 were cut into 250 x 100 mm unannealed sheets (sheet thickness 0.8 mmt) to obtain test steel sheets. After pretreating this steel sheet by various methods shown in Table 2 described later, hot-dip galvanizing was performed using a vertical hot-dip galvanizing apparatus. The steel sheet was annealed at 750 to 850 ° C x 60 s in an atmosphere of N 2 + 26% H 2 with a dew point of -22 ° C to -50 ° C and an oxygen concentration of 1 to 8 ppm in this apparatus, and then,
After cooling to steel plate temperature of 460 ℃, total Al concentration 0.137%, total Fe
Hot-dip galvanizing was performed in a hot-dip galvanizing bath with a concentration of 0.020%. The plating time was 1 s, and the Zn adhesion amount was adjusted to about 50 g / m 2 (per surface) with a gas wiper. The hot-dip galvanized test piece was immersed in a salt bath at 500 ° C for 18 to 21 seconds for alloying treatment.
【００２４】[0024]
【表１】 [Table 1]
【００２５】このようにして合金化処理を施した供試材
の機械的特性を調査するためJIS 5号試験片により引張
り試験を行った。各供試材について伸び(El)とランクフ
ォード値 (ｒ値、圧延方向) を表２の中に示した。また
合金化処理後の試料から25mmφの試験片を採取、0.5vol
％のインヒビター(商品名、朝日化学製「インビット710
N」) を含有した10％HCl 液でめっき層を溶解し、これ
をICPQ法でめっき層の組成分析に供するとともに、残部
鋼板をＸ線回折の試料とした。めっき層中のFe濃度、つ
まりFe/(Fe＋Zn)(％) を表２に示す。なお、めっき層中
のAl濃度、つまりAl/Zn(％) は0.19％であった。A tensile test was carried out using JIS No. 5 test pieces in order to investigate the mechanical properties of the test materials thus alloyed. Table 2 shows the elongation (El) and the Rankford value (r value, rolling direction) for each test material. Also, a 25 mmφ test piece was taken from the sample after the alloying treatment, and 0.5 vol
% Inhibitor (brand name, Asahi Kagaku "Inbit 710"
The plating layer was dissolved with a 10% HCl solution containing N ") and subjected to composition analysis of the plating layer by the ICPQ method, and the remaining steel plate was used as a sample for X-ray diffraction. Table 2 shows the Fe concentration in the plating layer, that is, Fe / (Fe + Zn) (%). The Al concentration in the plating layer, that is, Al / Zn (%) was 0.19%.
【００２６】Ｘ線回折積分強度の測定装置は理学電機製
RU-200であり、1 degree/minの速度で行った。最初に酸
洗面を測定し、その後板厚の1/4 まで化学研磨を行い、
その面の測定を行った。結果はそれぞれ表面、内部とし
て表２に示す。ただし、上記測定装置(RU-200)は、Mo管
球を用い加速電圧30kv、電流100mA の条件で測定を行う
ものであって、またＸ線回折積分強度Ｉ(222) ／Ｉ(20
0) は下記の式により基準化した値を用い、その比を求
めた。X-ray diffraction integrated intensity measuring device is manufactured by Rigaku Denki
RU-200, and the speed was 1 degree / min. First, measure the pickled surface, then chemically polish to 1/4 of the plate thickness,
The surface was measured. The results are shown in Table 2 as the surface and the inside, respectively. However, the above-mentioned measuring device (RU-200) uses a Mo tube for measurement under the conditions of an acceleration voltage of 30 kv and a current of 100 mA, and the X-ray diffraction integrated intensity I (222) / I (20
For (0), a value normalized by the following formula was used, and the ratio was calculated.
【００２７】 Ｉ(hkl) ＝ [I(hkl)m −Ｉb]／Ｉ(hkl)s Ｉ(hkl) : 規準化された(hkl) 面の積分強度 Ｉ(hkl)m : (hkl) 面の強度カウント Ｉb : バックグラウンドカウント Ｉ(hkl)s : 還元Fe標準試料の(hkl) 面の積分強度 次いで、前述のようにして合金化処理を施した供試材か
らJIS K6850 準拠の引張り剪断試験片を作成し、引張り
剪断試験を行った。I (hkl) = [I (hkl) m −Ib] / I (hkl) s I (hkl): Normalized integrated intensity of (hkl) plane I (hkl) m: (hkl) plane Strength count Ib: Background count I (hkl) s: Integrated strength of (hkl) plane of reduced Fe standard sample Then, a tensile shear test piece according to JIS K6850 from the test material alloyed as described above. Was prepared and subjected to a tensile shear test.
【００２８】使用した接着剤は、 (株) コニシ製「ＣＹ
ＢＯＮＤ」 (商品名) で、これを約３μm の厚みに塗布
した。このようにめっき面を接着剤で接合した試験片の
引張り試験を行い、剥離もしくは破壊箇所を特定し、合
金化溶融亜鉛めっき鋼板のめっき／鋼界面での剥離面積
比率を用いて密着性を評価した。結果は表２まとめて示
す。この比率が大きいと密着性が低く、小さいと密着性
が高いため、接着剤／めっき界面での剥離もしくは接着
剤の凝集破壊が生じていることを示す。比較例では、い
ずれも鋼／めっき界面の密着性が不十分 (剥離面積率30
％超)か機械的特性が不十分(El 45％未満、ｒ値 1.5未
満) である。The adhesive used is "CY" manufactured by Konishi Co., Ltd.
BOND ”(trade name) was applied to a thickness of about 3 μm. In this way, the tensile test of the test piece with the plated surface bonded with an adhesive is performed, the peeling or breaking point is specified, and the adhesion is evaluated using the peeling area ratio at the plating / steel interface of the galvannealed steel sheet. did. The results are summarized in Table 2. If this ratio is large, the adhesiveness is low, and if it is small, the adhesiveness is high, indicating that peeling at the adhesive / plating interface or cohesive failure of the adhesive occurs. In each of the comparative examples, the adhesion at the steel / plating interface is insufficient (peeling area ratio 30
%) Or insufficient mechanical properties (El less than 45%, r value less than 1.5).
【００２９】[0029]
【表２】 [Table 2]
【００３０】[0030]
【発明の効果】以上のように、本発明にかかる合金化溶
融亜鉛めっき鋼板は、めっき皮膜の界面剪断剥離強度を
向上させた優れた表面処理鋼板として、特に家電用塗装
鋼板および自動車用鋼板として有用である。INDUSTRIAL APPLICABILITY As described above, the galvannealed steel sheet according to the present invention is an excellent surface-treated steel sheet with improved interfacial shear peel strength of the plating film, especially as a coated steel sheet for household appliances and a steel sheet for automobiles. It is useful.
Claims (1)
き層から構成された合金化溶融亜鉛めっき鋼板であっ
て、該極低炭素鋼板が、Ｃ≦0.008 重量％、Ｐ≦0.03重
量％、かつTi≧0.02重量％またはTi＋Nb≧0.02重量％で
あり、さらに該極低炭素鋼板の表層のフェライト方位
が、Ｘ線回折積分強度比で Ｉ(222) ／Ｉ(200) ≦ 3.8 鋼板内部のフェライト方位が、同じくＸ線回折積分強度
比で Ｉ(222) ／Ｉ(200) ≧ 12 であり、前記めっき層が、重量割合で、Al／Zn≧0.15
％、Fe／(Fe+Zn): 8〜15％であることを特徴とする合金
化溶融亜鉛めっき鋼板。Claim: What is claimed is: 1. An alloyed hot-dip galvanized steel sheet comprising an ultra low carbon steel sheet and a plating layer coated thereon, wherein the ultra low carbon steel sheet has C≤0.008% by weight. , P ≦ 0.03% by weight and Ti ≧ 0.02% by weight or Ti + Nb ≧ 0.02% by weight, and the ferrite orientation of the surface layer of the ultra-low carbon steel sheet is I (222) / I (200 ) 3.8 The ferrite orientation inside the steel sheet is I (222) / I (200) ≧ 12 in the same X-ray diffraction integrated intensity ratio, and the plating layer is Al / Zn ≧ 0.15 in weight ratio.
%, Fe / (Fe + Zn): 8 to 15%, an alloyed hot-dip galvanized steel sheet.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP18892091A JP2600528B2 (en) | 1991-07-29 | 1991-07-29 | Galvannealed steel sheet |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP18892091A JP2600528B2 (en) | 1991-07-29 | 1991-07-29 | Galvannealed steel sheet |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0533111A true JPH0533111A (en) | 1993-02-09 |
| JP2600528B2 JP2600528B2 (en) | 1997-04-16 |
Family
ID=16232201
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP18892091A Expired - Lifetime JP2600528B2 (en) | 1991-07-29 | 1991-07-29 | Galvannealed steel sheet |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2600528B2 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2007066600A1 (en) * | 2005-12-06 | 2007-06-14 | Kabushiki Kaisha Kobe Seiko Sho | High-strength galvannealed sheet steels excellent in powdering resistance and process for production of the same |
| JP2014058741A (en) * | 2012-08-22 | 2014-04-03 | Nippon Steel & Sumitomo Metal | Hot dip galvannealed steel sheet excellent in productivity and press formability and production method thereof |
-
1991
- 1991-07-29 JP JP18892091A patent/JP2600528B2/en not_active Expired - Lifetime
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2007066600A1 (en) * | 2005-12-06 | 2007-06-14 | Kabushiki Kaisha Kobe Seiko Sho | High-strength galvannealed sheet steels excellent in powdering resistance and process for production of the same |
| EP1978113A1 (en) * | 2005-12-06 | 2008-10-08 | Kabushiki Kaisha Kobe Seiko Sho | High-strength galvannealed sheet steels excellent in powdering resistance and process for production of the same |
| US8025982B2 (en) | 2005-12-06 | 2011-09-27 | Kobe Steel, Ltd. | High-strength hot dip galvannealed steel sheet having high powdering resistance and method for producing the same |
| EP1978113A4 (en) * | 2005-12-06 | 2011-09-28 | Kobe Steel Ltd | High-strength galvannealed sheet steels excellent in powdering resistance and process for production of the same |
| EP1978113B1 (en) | 2005-12-06 | 2018-08-01 | Kabushiki Kaisha Kobe Seiko Sho | High-strength galvannealed sheet steels excellent in powdering resistance and process for production of the same |
| JP2014058741A (en) * | 2012-08-22 | 2014-04-03 | Nippon Steel & Sumitomo Metal | Hot dip galvannealed steel sheet excellent in productivity and press formability and production method thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2600528B2 (en) | 1997-04-16 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| KR101636443B1 (en) | HOT-DIP Al-Zn COATED STEEL SHEET AND METHOD FOR MANUFACTURING THE SAME | |
| JP3898923B2 (en) | High-strength hot-dip Zn-plated steel sheet excellent in plating adhesion and ductility during high processing and method for producing the same | |
| JP3684135B2 (en) | Si-containing high-strength hot-dip galvanized steel sheet with excellent corrosion resistance and method for producing the same | |
| US20200216927A1 (en) | Hot dipped high manganese steel and manufacturing method therefor | |
| KR102527548B1 (en) | plated steel | |
| JP3267178B2 (en) | Zn-Al alloy plated steel sheet with excellent workability | |
| JPH06256903A (en) | Galvannealed steel sheet excellent in press workability and plating peeling resistance | |
| JP2002309358A (en) | Galvannealed steel sheet with excellent workability | |
| JP2841889B2 (en) | Manufacturing method of alloyed hot-dip galvanized steel sheet | |
| JP2002004018A (en) | High strength hot-dip galvanized steel sheet having good corrosion resistance after coating and good press- workability, and coated steel sheet | |
| JP3163986B2 (en) | Galvannealed steel sheet | |
| JP2600528B2 (en) | Galvannealed steel sheet | |
| JPH11140587A (en) | Galvannealed steel sheet excellent in plating adhesion | |
| JPH0681099A (en) | Galvannealed steel sheet | |
| JP2002371342A (en) | Hot-dip galvanized steel sheet and manufacturing method therefor | |
| JP2000336467A (en) | Galvanized steel sheet and production thereof | |
| JP2932701B2 (en) | Galvannealed steel sheet | |
| JP2903732B2 (en) | Alloyed hot-dip galvanized steel sheet | |
| JP4846550B2 (en) | Steel plate for galvannealed alloy and galvannealed steel plate | |
| JP3198900B2 (en) | Manufacturing method of thin galvanized steel sheet | |
| JP3198902B2 (en) | Manufacturing method of thin galvanized steel sheet | |
| JPH05311372A (en) | Galvannealed steel sheet for adhesive structure | |
| JP2756547B2 (en) | Hot-dip Zn-based plating of hard-to-plate steel sheet | |
| JP2002173756A (en) | High strength galvannealed steel sheet having excellent plating adhesion and corrosion resistance, and method of manufacturing the same | |
| JPH05148604A (en) | Manufacture of galvanized steel sheet |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 19961119 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20080129 Year of fee payment: 11 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20090129 Year of fee payment: 12 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20100129 Year of fee payment: 13 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20110129 Year of fee payment: 14 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20120129 Year of fee payment: 15 |
|
| EXPY | Cancellation because of completion of term | ||
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20120129 Year of fee payment: 15 |