JP3202539B2 - Hot-dip ferritic stainless steel sheet excellent in bending workability and method for producing the same - Google Patents
Hot-dip ferritic stainless steel sheet excellent in bending workability and method for producing the sameInfo
- Publication number
- JP3202539B2 JP3202539B2 JP13688895A JP13688895A JP3202539B2 JP 3202539 B2 JP3202539 B2 JP 3202539B2 JP 13688895 A JP13688895 A JP 13688895A JP 13688895 A JP13688895 A JP 13688895A JP 3202539 B2 JP3202539 B2 JP 3202539B2
- Authority
- JP
- Japan
- Prior art keywords
- hot
- steel sheet
- dip
- stainless steel
- alloy layer
- 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.)
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Description
【0001】[0001]
【産業上の利用分野】本発明は、建築外装材、自動車部
材等、曲げ加工や比較的軽度のプレス加工を受ける用途
に適用される溶融めっきフェライト系ステンレス鋼板お
よびその製造法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot-dip coated ferritic stainless steel sheet applicable to applications such as architectural exterior materials and automobile parts, which are subjected to bending and relatively light pressing, and a method for producing the same.
【0002】[0002]
【従来の技術】Al系やZn系の溶融めっきを施したフ
ェライト系ステンレス鋼板は、その優れた耐食性、耐候
性に加え、外観の美麗さや色調、防眩性等いわゆる意匠
性の上でも種々の表面を比較的容易に提供できることか
ら、近年外装用建材を主としてその適用範囲が急速に広
まりつつある。2. Description of the Related Art In addition to its excellent corrosion resistance and weather resistance, ferritic stainless steel sheets which have been subjected to hot-dip plating of Al-based and Zn-based alloys have various appearances such as beautiful appearance, color tone, and anti-glare properties. Since the surface can be provided relatively easily, its application range has been rapidly expanding mainly for exterior building materials in recent years.
【0003】ステンレス鋼の表面はいわゆる不動態皮膜
で覆われているために、また溶融めっきを施す際の製造
工程内における加熱処理によって生成する表面酸化皮膜
のために、一般に溶融めっきした場合のめっき密着性の
確保や点状のめっき欠陥の回避が難しく、従来この点を
改良し健全な溶融めっき鋼板を製造するためのさまざま
な工夫が提案されてきた。[0003] Since the surface of stainless steel is covered with a so-called passivation film, and because of a surface oxide film generated by a heat treatment in a manufacturing process when hot-dip coating is performed, plating is generally performed by hot-dip plating. It is difficult to ensure adhesion and avoid spot-like plating defects. Conventionally, various measures have been proposed to improve this point and produce a sound hot-dip coated steel sheet.
【0004】例えば、Cr含有鋼の溶融めっき密着性の
改善手段として、特開昭60−262950号公報、特
開昭61−147865号公報には予めNiを電気めっ
きすることでその後の溶融めっき層の健全性を確保する
技術が、また特開昭64−28351号公報には同様の
目的でFe−B合金をプレめっきする技術が開示されて
いる。さらには、特開平2−250948号、特開平3
−28358号、特開平3−28359号、特開平3−
36250号、特開平3−56654号、特開平3−6
4437号、特開平3−64438号及び特開平3−6
4439号の各公報にはいずれもCr含有鋼の溶融めっ
きに際し、工程中の加熱処理時に生成する表面酸化物の
還元をより容易にし、かつめっき金属と母材との間に形
成する脆弱な合金層の厚さを減ずることで、曲げ加工時
のめっき密着性を改善しようとする技術が開示されてい
る。For example, Japanese Patent Application Laid-Open Nos. Sho 60-262950 and 61-147865 disclose a method of improving the adhesion of hot-dip plating of Cr-containing steel by pre-electroplating Ni to form a hot-dip coating layer. A technique for pre-plating an Fe-B alloy for the same purpose is disclosed in JP-A-64-28351. Further, JP-A-2-250948, JP-A-3-250948,
-28358, JP-A-3-28359, JP-A-3-28359
No. 36250, JP-A-3-56654, JP-A-3-6
No. 4437, JP-A-3-64438 and JP-A-3-6
No. 4439 discloses a fragile alloy formed between a plated metal and a base material, which facilitates the reduction of surface oxides generated during heat treatment during the process of hot dip plating of Cr-containing steel. There is disclosed a technique for improving the plating adhesion during bending by reducing the thickness of a layer.
【0005】[0005]
【発明が解決しようとする課題】しかしながら、こうし
ためっき密着性や溶融めっき鋼板としての加工性が改善
された溶融めっきフェライト系ステンレス鋼板にあって
も、曲げ加工された場合、基材のフェライト系ステンレ
ス鋼板が劈開破面を呈する脆性割れが発生するという問
題がある。However, even in such a hot-dip ferritic stainless steel sheet having improved plating adhesion and workability as a hot-dip coated steel sheet, the ferritic stainless steel as a base material when bent is formed. There is a problem that a brittle crack in which a steel plate exhibits a cleavage fracture surface occurs.
【0006】ことに、近年のように種々の排気ガスや煤
煙等による大気腐食環境が厳しくなりつつある状況下で
は、溶融めっき鋼板の基材自体の耐錆性、耐候性をより
優れたものとする必要性から、基材のCr量の増加や、
Mo,Nb等の元素が添加された、より高合金が使用さ
れるようになってきており、その分必然的に加工性が低
下するため、こうした溶融めっきフェライト系ステンレ
ス鋼は加工割れが発生し易いものとなる。[0006] Particularly, in a situation where the atmospheric corrosion environment due to various exhaust gases and soot is becoming severe as in recent years, the rust resistance and weather resistance of the base material itself of the hot-dip coated steel sheet are improved. To increase the amount of Cr in the base material,
Higher alloys to which elements such as Mo and Nb are added have been used, and workability is inevitably reduced by that amount. Therefore, such hot-dip ferritic stainless steels have work cracks. It will be easy.
【0007】さらに、建築外装材の中で特に溶融めっき
フェライト系ステンレス鋼板の用途として急速に適用が
拡大しつつある屋根材では、より長尺の部材が施工上も
有利であることから、その加工は素材の長手方向に連続
的に施すロールフォーミングが主流であり、曲げ形状が
比較的複雑で局部的な曲げ半径が板厚と同等程度の厳し
いものが多くかつその加工速度も比較的速いことから、
溶融めっきフェライト系ステンレス鋼板の加工割れが発
生し易い状況となっている。[0007] Further, in the case of roofing materials, which are rapidly expanding in use as hot-dip ferritic stainless steel sheets among building exterior materials, in particular, the use of longer members is advantageous in construction. The mainstream is roll forming, which is performed continuously in the longitudinal direction of the material.Because the bending shape is relatively complicated, the local bending radius is often as severe as the plate thickness, and the processing speed is relatively fast. ,
Hot-dip galvanized ferritic stainless steel sheets are easily cracked.
【0008】このような加工割れについて、例えば溶融
Alめっきフェライト系ステンレス鋼板の場合をみる
と、基材とめっき層の境界部には、脆弱な合金層を形成
するが、この合金層が厚くなり過ぎると加工の際に容易
に割れを発生し、めっき層の破断を誘発することが知ら
れており、このことから合金層の過度な成長を抑える作
用を有するSiが10wt%程度Al浴に添加され、Al
−Fe−Siを主成分とする合金層を3μm程度の厚さ
に止めることが通常行われている。しかし、この合金層
は非常に硬くかつ脆いので、厳しい加工が行われる際に
は割れが入ることが避けられない。一方で、この合金層
が存在しない場合には加工部のめっき層の密着性に問題
があり、例えば平板の状態で実施されるいわゆるボール
インパクトテスト等のめっき剥離テストでは不具合がな
くとも、曲げ加工後の特に外側表面のテープ剥離テスト
では容易にめっき剥離が認められるようになる。[0008] Regarding such work cracking, for example, in the case of a hot-dip Al-plated ferritic stainless steel sheet, a brittle alloy layer is formed at the boundary between the base material and the plating layer, but this alloy layer becomes thicker. It is known that when it is too long, cracks are easily generated during processing, which causes breakage of the plating layer. Therefore, about 10 wt% of Si having an effect of suppressing excessive growth of the alloy layer is added to the Al bath. And Al
It is common practice to stop the alloy layer containing -Fe-Si as a main component to a thickness of about 3 µm. However, since this alloy layer is very hard and brittle, it is inevitable that cracks will occur when severe processing is performed. On the other hand, when this alloy layer does not exist, there is a problem in the adhesion of the plating layer in the processed portion. For example, even if there is no defect in a plating peeling test such as a so-called ball impact test performed in a flat state, bending processing is performed. Later, particularly in the tape peeling test of the outer surface, plating peeling can be easily recognized.
【0009】しかしながら、こうした曲げ後のめっき密
着性の悪いものにあっては、基材ステンレスにまで達す
る割れは発生しないことが明らかとなった。すなわち、
溶融めっきフェライト系ステンレス鋼板における合金層
は、加工部のめっき密着性の確保の上では有用であるも
のの、加工割れを誘発する起点となり易いという有害な
作用を併せ持つのである。[0009] However, it has been clarified that cracks down to the base stainless steel do not occur in such poor plating adhesion after bending. That is,
The alloy layer in the hot-dip ferritic stainless steel sheet is useful for ensuring the plating adhesion of the processed portion, but also has a detrimental effect that it is likely to be a starting point for inducing a work crack.
【0010】さらに、本発明者らの検討によれば、こう
した溶融めっきフェライト系ステンレス鋼板の曲げ加工
において基材にまで割れが発生する場合には、まず、一
旦合金層に脆性的な割れが発生し、そこが起点となって
めっき層および基材ステンレス層内に伝播するのである
が、この際とくに基材側に伝播する割れは、その初期に
おいて脆性破面を呈するものであることが明らかとなっ
た。さらに、一般に曲げ加工性の改善には延性の改善が
有効とされているが、溶融めっきフェライト系ステンレ
ス鋼板にあっては、基材の延性を改善しただけでは上記
のような、合金層を起点として基材内部への脆性破壊の
進展を抑えることが困難であることが判明した。すなわ
ち、溶融めっきフェライト系ステンレス鋼板の曲げ性改
善のためには、従来知見による延性向上対策とは異な
る、新しい知見に基づいた改善が必要である。Further, according to the study of the present inventors, when such a hot-dip coated ferritic stainless steel sheet is cracked to the base material, first, brittle cracks are first formed in the alloy layer. Then, it becomes the starting point and propagates in the plating layer and the base stainless steel layer. At this time, it is clear that the crack that propagates particularly to the base material side exhibits a brittle fracture surface in the initial stage. became. Furthermore, although ductility is generally considered to be effective in improving bending workability, in hot-dip ferritic stainless steel sheets, simply improving the ductility of the base material causes the starting point of the alloy layer as described above. It has been found that it is difficult to suppress the progress of brittle fracture inside the substrate. That is, in order to improve the bendability of a hot-dip ferritic stainless steel sheet, it is necessary to make improvements based on new knowledge, which is different from ductility improvement measures based on conventional knowledge.
【0011】本発明は、上記のような状況に鑑み、ロー
ルフォーミングの如き比較的速い加工速度で曲げ半径が
板厚程度の厳しい曲げ加工を連続的に施した場合でも、
加工割れが発生せずかつ曲げ加工部のめっき密着性にも
優れた溶融めっきフェライト系ステンレス鋼板を提供す
ることを目的とするものである。[0011] In view of the above situation, the present invention is intended to be applied to a case where a severe bending process having a bending radius of about a plate thickness is continuously performed at a relatively high processing speed such as roll forming.
It is an object of the present invention to provide a hot-dip coated ferritic stainless steel sheet that does not cause processing cracks and has excellent plating adhesion at a bent portion.
【0012】[0012]
【課題を解決するための手段】本発明は、上述したよう
に従来の考え方とは異なる新しい知見に基づいてなされ
たもので、フェライト系ステンレス鋼板にAlあるいは
Zn等のいわゆる溶融めっきを施した際にめっき層と基
材ステンレス鋼板との境界部に形成する硬質かつ脆弱な
合金層内に微細な亀裂がある一定以上の頻度で存在した
ものでは、曲げ加工によって発生する応力が、合金層内
に存在する微細亀裂が開口することで解放されるため
に、基材内部への脆性的な亀裂の伝播が必然的に回避さ
れることとなり、従って、溶融フェライト系ステンレス
鋼板として、その合金層内に一定の頻度以上の微小亀裂
を含むものは、厳しい曲げ加工を受けても基材ステンレ
スに割れが発生し難く、まためっき層の割れも最少に維
持できるのみならず、めっき層の密着性も良好という優
れた特性を具備することを知見し、完成したものであ
る。SUMMARY OF THE INVENTION The present invention has been made on the basis of a new finding different from the conventional concept as described above, and is applied to a case where a so-called hot-dip plating such as Al or Zn is applied to a ferritic stainless steel sheet. In the hard and brittle alloy layer formed at the boundary between the plating layer and the base stainless steel plate, if there is a micro-crack at a certain frequency or more, the stress generated by the bending process will be Since the existing microcracks are released by opening, the propagation of brittle cracks inside the substrate is inevitably avoided, and therefore, as a molten ferritic stainless steel sheet, For those containing micro-cracks of a certain frequency or more, even if subjected to severe bending, the base stainless steel is unlikely to crack and the cracks in the plating layer can be kept to a minimum. Adhesiveness of the plating layer was found that having a good property of good, has been completed.
【0013】すなわち本発明は、フェライト系ステンレ
ス被めっき鋼板表面と溶融めっき層との境界面に、前記
ステンレス鋼と溶融めっき金属との合金層が存在し、か
つ前記合金層中に亀裂を有することを特徴とする曲げ加
工性に優れた溶融めっきフェライト系ステンレス鋼板お
よびその製造法を要旨とする。[0013] That is, the present invention provides that an alloy layer of the stainless steel and the hot-dip metal exists at a boundary surface between the surface of the ferritic stainless steel-plated steel sheet and the hot-dip coating layer, and that the alloy layer has a crack. The gist of the present invention is a hot-dip ferritic stainless steel sheet having excellent bending workability and a method for producing the same.
【0014】すなわち具体的には、フェライト系ステン
レス被めっき鋼板と溶融めっき層との境界面に、前記ス
テンレス鋼と溶融めっき金属との合金層が面積率で少な
くとも60%以上存在し、かつめっき鋼板表面に垂直な
任意の断面から見て前記合金層厚みの50%以上の長さ
を有する微細な亀裂を被めっき鋼板表面に平行な長さ1
mm当たり50本以上前記合金層中に有することを特徴と
する曲げ加工性に優れた溶融めっきフェライト系ステン
レス鋼板であり、また、フェライト系ステンレス被めっ
き鋼板と溶融めっき層との境界面に、前記ステンレス鋼
と溶融めっき金属との合金層が面積率で少なくとも60
%以上存在し、必要に応じて350〜400℃の温度に
5時間以上保定した後、被めっき鋼板と溶融めっき金属
との合金層に、最大伸び率0.1%以上を加えることに
よって、めっき鋼板表面に垂直な任意の断面から見て前
記合金層厚みの50%以上の長さを有する微細な亀裂を
被めっき鋼板表面に平行な長さ1mm当たり50本以上前
記合金層中に存在させることを特徴とする曲げ加工性に
優れた溶融めっきフェライト系ステンレス鋼板の製造法
である。That is, specifically, at the interface between the ferritic stainless steel-plated steel sheet and the hot-dip coating layer, an alloy layer of the stainless steel and the hot-dip metal is present in an area ratio of at least 60% or more. When viewed from an arbitrary cross section perpendicular to the surface, a fine crack having a length of 50% or more of the alloy layer thickness is formed in a length 1 parallel to the surface of the steel plate to be plated.
It is a hot-dip ferritic stainless steel sheet excellent in bending workability characterized by having in the alloy layer 50 or more per mm, and at the interface between the ferritic stainless steel plated steel sheet and the hot-dip coating layer, The alloy layer of stainless steel and hot-dip plating metal has an area ratio of at least 60.
% Or more and, if necessary, maintained at a temperature of 350 to 400 ° C. for 5 hours or more, and then, by adding a maximum elongation of 0.1% or more to the alloy layer of the steel sheet to be plated and the hot-dip metal, Fine cracks having a length of 50% or more of the thickness of the alloy layer as viewed from an arbitrary cross section perpendicular to the surface of the steel sheet are present in the alloy layer at a rate of 50 or more per 1 mm parallel to the surface of the steel sheet to be plated. This is a method for producing a hot-dip coated ferritic stainless steel sheet having excellent bending workability.
【0015】上記方法において、最大伸び率0.1%以
上を加える手段として、スキンパス圧延、半径100mm
以下のロールを1本以上通過させるベンディング型レベ
ラー矯正、テンション型レベラー矯正の何れかまたは2
種以上を施すことができる。また、上記フェライト系ス
テンレス鋼板は重量%でC :0.08%以下、
Si:1.0%以下、Mn:1.0%以下、
Cr:11〜25%、N :0.03%以下を含有
し、さらに必要に応じてNb:1.5%以下、
Ti:0.5%以下、Mo:2.5%以下、
Cu:0.5%以下の1種または2種以上を含有し、
残部がFeおよび不可避不純物からなることを特徴とす
る。また溶融めっき金属としてはZnを主成分とする金
属、またはAlを主成分とする金属とすることができ
る。In the above method, as means for adding a maximum elongation of 0.1% or more, skin pass rolling, a radius of 100 mm
Either one of bending type leveler straightening and tension type leveler straightening that passes one or more of the following rolls or 2
Seeds or more can be applied. The ferritic stainless steel sheet has a C content of 0.08% or less by weight,
Si: 1.0% or less, Mn: 1.0% or less,
Cr: 11 to 25%, N: 0.03% or less, and if necessary, Nb: 1.5% or less,
Ti: 0.5% or less, Mo: 2.5% or less,
Cu: contains 0.5% or less of one or more kinds,
The balance is made up of Fe and unavoidable impurities. The hot-dip plating metal may be a metal containing Zn as a main component or a metal containing Al as a main component.
【0016】[0016]
【作用】次に、本発明についてさらに詳細に説明する。
まず、本発明にいう溶融めっきフェライト系ステンレス
鋼にあっては、溶融めっき層と被めっきステンレス鋼板
との境界部に形成される合金層は、面積率で60%以上
存在することが必要である。これよりも少ない場合には
曲げ加工性によってめっき層が容易に剥離する可能性が
著しく高くなる。合金層は、通常の光学顕微鏡による金
属断面組織観察手法によって200倍程度でその有無を
充分確認できるものである。本発明にいう合金層の面積
率とは鋼板表面に垂直な任意の断面を200倍の視野に
て少なくとも20視野以上観察した結果から決定したも
のであり、観察視野内の鋼板表面に平行な長さ当たりに
合金層が存在する長さの割合のことである。Next, the present invention will be described in more detail.
First, in the hot-dip ferritic stainless steel according to the present invention, the alloy layer formed at the boundary between the hot-dip layer and the stainless steel plate to be plated needs to be present in an area ratio of 60% or more. . If the amount is less than this, the possibility that the plating layer is easily peeled off due to the bending workability becomes extremely high. The presence or absence of the alloy layer can be sufficiently confirmed at a magnification of about 200 times by an ordinary technique for observing a metal cross-sectional structure using an optical microscope. The area ratio of the alloy layer referred to in the present invention is determined from the result of observing any cross section perpendicular to the steel sheet surface in at least 20 visual fields at a magnification of 200 times, and the length parallel to the steel sheet surface in the observation visual field. It is the ratio of the length where the alloy layer exists at a time.
【0017】一方、合金層が面積率で60%以上存在す
る場合めっき層の密着性は確保されるけれども、一般に
合金層は非常に脆弱であるため、曲げ加工された場合に
はこの合金層から脆性的な割れが発生し、被めっきステ
ンレス鋼板内部やめっき層へ伝播して、被めっき鋼板自
体の割れやめっき層の割れの原因となる。これを抑える
ためには合金層自体に予め微細な亀裂をある頻度以上で
発生させておくことが重要であることがわかった。すな
わち、種々検討の結果、めっき鋼板表面に垂直な断面観
察した場合鋼板表面に平行な長さ1mm当たり50本以上
が必要でる。これ以下の頻度では、例えば90゜曲げを
行なう場合、被めっきステンレス鋼板表面に割れが発生
する可能性が著しく高くなる。さらに、180゜曲げや
加工速度の速い厳しい加工を施す場合には、微細な亀裂
を長さ1mm当たり90本以上とすることが好ましい。On the other hand, when the alloy layer is present in an area ratio of 60% or more, the adhesion of the plating layer is ensured, but the alloy layer is generally very fragile. Brittle cracks occur and propagate to the inside of the stainless steel plate to be plated and to the plating layer, causing cracks in the plated steel plate itself and in the plating layer. It has been found that in order to suppress this, it is important to previously generate fine cracks in the alloy layer itself at a certain frequency or more. That is, as a result of various studies, when a cross section perpendicular to the surface of the plated steel sheet is observed, 50 or more pieces are required per 1 mm length parallel to the steel sheet surface. If the frequency is lower than this, for example, when a 90 ° bending is performed, the possibility that cracks occur on the surface of the stainless steel plate to be plated becomes extremely high. Further, in the case of performing 180 ° bending or severe processing with a high processing speed, it is preferable that the number of fine cracks is 90 or more per 1 mm in length.
【0018】なお、ここでいう合金層中の微細な亀裂と
は、図1の模式図に示すように、合金層厚みの50%以
上の長さを有し、通常の光学顕微鏡による金属断面組織
観察手法によって200倍程度で充分確認できるもので
あり、本発明にいう長さ1mm当たり50本とは200倍
の視野にて少なくとも20視野以上観察した結果から決
定したものである。合金層中の亀裂の長さが合金層厚み
の50%未満の亀裂も含めて1mm当たり50本以上とし
ても、曲げ加工によって被めっきステンレス鋼板に割れ
が生ずることがあることから、亀裂の長さは合金層厚み
の50%以上とした。The fine cracks in the alloy layer referred to herein are, as shown in the schematic diagram of FIG. 1, a length of 50% or more of the thickness of the alloy layer, and a metal cross-sectional structure by a normal optical microscope. It can be sufficiently confirmed at about 200 times by an observation method, and the number of 50 lines per 1 mm in the present invention is determined from the result of observation of at least 20 visual fields in a 200 times visual field. Even if the length of the cracks in the alloy layer is 50 or more per mm including cracks of less than 50% of the thickness of the alloy layer, cracks may occur in the stainless steel plate to be plated by bending, so the length of the cracks Is 50% or more of the thickness of the alloy layer.
【0019】次に、被めっきステンレス鋼の成分の限定
理由について述べる。Cはフェライト系ステンレス鋼の
靭性を低下させる元素であり、本発明の場合0.08wt
%がその上限となる。この範囲を超えてCが含有される
溶融めっきフェライト系ステンレス鋼板にあっては、例
え合金層中の微小亀裂の存在頻度が90本/mm以上あっ
ても基材靭性が劣るため曲げ加工時に割れが発生し易く
なる。NもCと全く同様の理由でその上限は0.03wt
%となる。Next, the reasons for limiting the components of the stainless steel to be plated will be described. C is an element that lowers the toughness of the ferritic stainless steel.
% Is the upper limit. In the hot-dip ferritic stainless steel sheet containing C exceeding this range, even if the frequency of micro cracks in the alloy layer is 90 / mm or more, the base material is inferior in toughness. Is more likely to occur. The upper limit of N is 0.03 wt% for exactly the same reason as C.
%.
【0020】Siは、過剰に含有すると冷間での加工性
を著しく損なうばかりでなく、ホットコイルの靭性をも
低下させ、基材自体の製造性を低下させるため1.0wt
%以下とする。Mnは、脱酸剤およびSの粒界への偏析
抑制に有効な元素であるが、過剰添加は素材の延性を低
下させるため1.0wt%以下とする。If Si is contained excessively, it not only impairs the workability in the cold significantly, but also lowers the toughness of the hot coil and lowers the productivity of the base material itself.
% Or less. Mn is an element effective for suppressing the segregation of the deoxidizing agent and S to the grain boundaries, but excessive addition lowers the content of 1.0 wt% or less because the ductility of the material is reduced.
【0021】Crはステンレス鋼にあっては、その耐食
性の上で必須の基本添加元素である。この意味から下限
は11wt%となる。一方、その含有量に応じてステンレ
ス鋼としての耐食性は向上するが25%を超えて添加さ
れても、その耐食性向上効果が飽和し、曲げ加工性は著
しく劣化するため、本発明にあっては25wt%をその上
限とする。Cr is a basic additive element essential for stainless steel in terms of its corrosion resistance. From this meaning, the lower limit is 11 wt%. On the other hand, the corrosion resistance as stainless steel is improved according to the content, but even if it is added in excess of 25%, the effect of improving the corrosion resistance is saturated, and the bending workability is significantly deteriorated. 25 wt% is the upper limit.
【0022】Nbは一般には溶接部の耐食性特に耐粒界
腐食性の確保、素材結晶粒の粗大化抑制、素材の強化に
有効な添加元素であり、フェライト系ステンレス鋼にあ
ってもこれらの目的で添加される場合が多い。本発明に
あっては、特に基材のフェライト系ステンレス鋼板の製
造性確保の点からホットコイル段階における靭性向上の
目的で、また製品板での加工性や強度確保の点から結晶
粒粗大化抑制の目的で、さらには溶接部耐食性確保のた
めに選択的に添加することができる。しかし、1.5wt
%を超えて添加するとこれらの効果は飽和するばかりで
なく、基材ステンレス鋼板の靭性を著しく劣化させるこ
とから、1.5wt%を上限とした。In general, Nb is an additive element effective for securing the corrosion resistance of the welded portion, particularly the intergranular corrosion resistance, suppressing the coarsening of the material crystal grains, and strengthening the material. Often added. In the present invention, in particular, for the purpose of improving the toughness at the hot coil stage from the viewpoint of ensuring the productivity of the ferritic stainless steel sheet as the base material, and suppressing the grain coarsening from the viewpoint of ensuring the workability and strength of the product sheet. Can be selectively added for the purpose of further improving the corrosion resistance of the welded portion. However, 1.5wt
%, These effects not only saturate, but also significantly deteriorate the toughness of the base stainless steel sheet, so the upper limit was 1.5 wt%.
【0023】TiはNbと同様の目的で本発明にあって
は選択的に添加することができる。しかし、0.5wt%
を超えて添加してもこれらの効果は飽和し、いたずらに
合金コストを上昇させることから、上限を0.5wt%と
した。Ti can be selectively added in the present invention for the same purpose as Nb. However, 0.5wt%
, The effect is saturated and the alloy cost is unnecessarily increased. Therefore, the upper limit is set to 0.5 wt%.
【0024】Moは、耐食性向上に有効な元素で、特に
Cr添加だけでは得られない局部腐食に対する抵抗力を
向上させる効果が大きいため、耐候性ステンレス鋼にあ
っては広く使用されており、本発明のような溶融めっき
フェライト系ステンレス鋼板の主たる利用目的からMo
についても選択的に添加できる。しかし、2.5wt%を
超えて添加しても、これらの効果は飽和し、いたずらに
合金コストを増大させることから、2.5wt%を上限と
した。Mo is an element effective in improving the corrosion resistance. In particular, Mo has a great effect of improving the resistance to local corrosion that cannot be obtained only by adding Cr. Therefore, Mo is widely used in weather-resistant stainless steel. From the main use of hot-dip ferritic stainless steel sheet as in the invention, Mo
Can also be selectively added. However, even if added in excess of 2.5 wt%, these effects are saturated and the alloy cost is unnecessarily increased. Therefore, the upper limit is set to 2.5 wt%.
【0025】CuはMoと同様の目的で本発明にあって
は選択的に添加することができる。しかし、0.5wt%
を超えて添加するとこれらの効果は飽和するばかりでは
なく、基材ステンレス鋼板の靭性を著しく劣化させるこ
とから、0.5wt%を上限とした。Cu can be selectively added in the present invention for the same purpose as Mo. However, 0.5wt%
If added in excess of, these effects not only saturate, but also significantly deteriorate the toughness of the base stainless steel sheet, so the upper limit was 0.5 wt%.
【0026】なお、Nb,Ti,MoおよびCuについ
てはそれぞれ上述したとおり、本発明にあっては選択的
に添加できるものであるが、本発明の溶融めっきフェラ
イト系ステンレス鋼板が主としてその耐候性を利用する
ものであること、また複雑な形状に加工される場合がほ
とんどであることから、これらの4元素は少なくとも1
種以上含むことが好ましい。As described above, Nb, Ti, Mo and Cu can be selectively added in the present invention, but the hot-dip ferritic stainless steel sheet of the present invention mainly has the weather resistance. These four elements are at least one because they are used and are often processed into complicated shapes.
It is preferred to include more than one species.
【0027】溶融めっき処理後、350〜400℃の温
度に5時間以上保定することが好ましい。350℃以上
に加熱保持することによって、めっき合金層が軟化し、
めっき鋼板の加工性が向上することから、下限を350
℃とした。しかし、400℃を超えて加熱保持すると、
被めっきステンレス鋼原板が脆化し、逆に曲げ加工性が
著しく阻害されることから、400℃を上限とした。ま
た、加熱保定時間が、5時間未満では、めっき合金層が
十分に軟化せず、曲げ加工性が十分に向上しないことか
ら、5時間以上とした。After the hot-dip plating, the temperature is preferably maintained at 350 to 400 ° C. for 5 hours or more. By heating and holding at 350 ° C. or higher, the plating alloy layer softens,
Since the workability of the plated steel sheet is improved, the lower limit is 350
° C. However, when heated and held above 400 ° C,
The upper limit was set to 400 ° C., because the stainless steel plate to be plated was embrittled and, conversely, the bending workability was significantly impaired. If the heating retention time is less than 5 hours, the plating alloy layer is not sufficiently softened, and the bending workability is not sufficiently improved.
【0028】次に、溶融めっきフェライト系ステンレス
鋼板の合金層に50本/mm以上の微細な亀裂を存在させ
るための手段の限定理由について述べる。被めっき鋼板
と溶融めっき金属との合金層に加える最大伸び率を0.
1%以上とした。ここで、最大伸び率とは、スキンパス
圧延、レベラー矯正などによって前記合金層の表裏面い
ずれかに直接加わる伸び変形率の最大値をいう。前記合
金層は、硬質で非常に脆弱であることから、わずかな最
大伸び率によっても容易に破砕される。0.1%以上の
最大伸び率によって合金層中の微細な亀裂を50本/mm
以上とすることが可能であることから、前記合金層に加
える最大伸び率の下限を0.1%とした。Next, the reason for limiting means for causing fine cracks of 50 / mm or more in the alloy layer of the hot-dip ferritic stainless steel sheet will be described. The maximum elongation to be added to the alloy layer of the steel sheet to be plated and the hot-dip metal is 0.
1% or more. Here, the maximum elongation refers to the maximum value of the elongation / deformation that is directly applied to one of the front and back surfaces of the alloy layer by skin pass rolling, leveler straightening, or the like. The alloy layer is hard and very fragile, so that it is easily crushed even with a slight maximum elongation. 50 cracks / mm in the alloy layer with a maximum elongation of 0.1% or more
Since the above can be achieved, the lower limit of the maximum elongation added to the alloy layer is set to 0.1%.
【0029】また、前述したように合金層は被めっき鋼
板や溶融めっき金属に比べて硬質であることから、合金
層に0.1%以上の最大伸びを加える手段として、スキ
ンパス圧延、半径100mm以下のロールを1本以上通過
させるベンディング型レベラー矯正、テンション型レベ
ラー矯正の1種または2種以上を施すことが好ましい。
スキンパス圧延は、めっき合金層の微細分断に有効であ
ることから、圧下率を0.1%以上とすることが望まし
い。しかし、あまり圧下率が大きいと、加工硬化し、逆
に曲げ加工性が劣化することから、3.0%以下とする
ことが望ましい。レベラー矯正もめっき合金層の微細分
断に有効である。レベラー矯正を行なう場合、ベンディ
ング型レベラーとテンション型レベラーの2種類があ
る。ベンディング型レベラー矯正を行なう場合、ロール
半径が100mmを超えるものは、めっき合金層に十分な
曲げ変形が加わらず、最大伸び率0.1%以上とするこ
とが困難で、めっき合金層の微細分断に至らないため、
ロール半径は100mm以下とした。また、テンション型
レベラー矯正を行なう場合、伸び率が0.1%未満で
は、合金層に0.1%以上の最大伸び率が加わらず、め
っき合金層の微細分断に至らないので、伸び率は0.1
%以上であることが望ましい。As described above, since the alloy layer is harder than the steel sheet to be plated or the hot-dip metal, skin pass rolling and a radius of 100 mm or less are used as means for applying a maximum elongation of 0.1% or more to the alloy layer. It is preferable to apply one or more of bending type leveler correction and tension type leveler correction in which one or more rolls pass through.
Since skin pass rolling is effective in finely dividing the plating alloy layer, it is desirable that the rolling reduction is 0.1% or more. However, if the rolling reduction is too large, work hardening occurs, and conversely, bending workability deteriorates. Leveler correction is also effective for fine division of the plating alloy layer. When performing leveler correction, there are two types of bending type levelers and tension type levelers. When performing bending-type leveler straightening, if the roll radius exceeds 100 mm, sufficient bending deformation is not applied to the plating alloy layer, and it is difficult to achieve a maximum elongation of 0.1% or more. Does not lead to
The roll radius was 100 mm or less. In addition, when performing a tension type leveler correction, if the elongation is less than 0.1%, the maximum elongation of 0.1% or more is not applied to the alloy layer, and the plating alloy layer is not finely divided. 0.1
% Is desirable.
【0030】[0030]
【実施例】表1に示す化学成分を有するフェライト系ス
テンレス鋼の0.8mm厚の冷延焼鈍板を用いてAlある
いはZnの溶融めっきフェライト系ステンレス鋼板を製
造した。その後、この溶融めっきフェライト系ステンレ
ス鋼板に表2に示す熱処理あるいはレベラー矯正、スキ
ンパス圧延を施して、t/2−90゜,180゜曲げを
行い、曲げ面の割れの有無を評価した。この結果を表2
に併せて示した。曲げ面の観察評価は、Al系のめっき
ではNaOHの濃厚水溶液でめっき金属層をさらにりん
酸水溶液でめっき合金層を溶解した後、またZn系のめ
っきでは硝酸水溶液でめっき金属層をさらにりん酸水溶
液でめっき合金層を溶解した後、肉眼で行なった。割れ
の評価は、全く割れのないものを評点1、逆に2枚に分
離するほどの割れは評点5とし、その間を官能的に3段
階に分類評価した。EXAMPLE A hot-rolled ferritic stainless steel sheet of Al or Zn was produced using a 0.8 mm thick cold-rolled annealed ferritic stainless steel having the chemical composition shown in Table 1. Thereafter, the hot-dip ferritic stainless steel sheet was subjected to the heat treatment or leveler straightening and skin pass rolling shown in Table 2, and was subjected to t / 2-90 ° and 180 ° bending to evaluate the presence or absence of cracks in the bent surface. Table 2 shows the results.
Are also shown. In the case of Al-based plating, the plating metal layer was dissolved with a concentrated aqueous solution of NaOH, and the plating alloy layer was further dissolved with a phosphoric acid aqueous solution. After dissolving the plating alloy layer with an aqueous solution, the measurement was performed with the naked eye. For the evaluation of cracks, those having no cracks were given a rating of 1, and conversely, cracks that could be separated into two pieces were given a rating of 5, and the interval between them was sensuously classified and evaluated in three stages.
【0031】[0031]
【表1】 [Table 1]
【0032】[0032]
【表2】 [Table 2]
【0033】[0033]
【表3】 [Table 3]
【0034】[0034]
【表4】 [Table 4]
【0035】[0035]
【表5】 [Table 5]
【0036】[0036]
【表6】 [Table 6]
【0037】その結果、溶融めっき金属と被めっきステ
ンレス鋼板の境界に生成した合金層の長さ1mmあたり5
0本以上クラックが発生しているNo.1〜42の試料
は、90゜曲げの曲げ面が健全で割れの発生もなく良好
な曲げ性を示した。特に、合金層の長さ1mmあたり90
本クラックが発生しているNo.2〜12、No.15
〜20、No.22〜30、No.32〜33、No.
35〜40、No.43〜46の試料は、180゜曲げ
においても曲げ面が健全で割れの発生もなく極めて良好
な曲げ性を示した。一方、比較に実施したレベラー矯正
およびスキンパス圧延を施すことなく合金層の長さ1mm
あたりのクラック数が50本未満のNo.47〜70の
試料は、90゜曲げおよび180゜曲げのいずれの曲げ
加工においても脆性破面を呈するクラックが発生した。As a result, 5 mm per 1 mm of the length of the alloy layer formed at the boundary between the hot-dip metal and the stainless steel plate to be plated.
No. 0 or more cracks occurred. The samples Nos. 1 to 42 exhibited good bendability with a 90 ° bending surface being sound and without cracking. In particular, 90 mm per 1 mm of the length of the alloy layer
No. in which this crack occurred. Nos. 2 to 12; Fifteen
-20, no. 22-30, No. 32 to 33;
35 to 40; The samples Nos. 43 to 46 exhibited a very good bending property even when bent at 180 ° without any cracks. On the other hand, the length of the alloy layer was 1 mm without performing the leveler straightening and skin pass rolling performed for comparison.
No. with less than 50 cracks per unit. Samples Nos. 47 to 70 exhibited cracks exhibiting brittle fracture surfaces in both bending at 90 ° and bending at 180 °.
【0038】[0038]
【発明の効果】本発明により、曲げ加工性の優れた溶融
めっきフェライト系ステンレス鋼板の製造が可能になっ
た。従来、曲げ加工性の不良な製品は歩留り落ちとせざ
るを得なかったが、本発明により製品歩留りが増大し、
工業的な利益は極めて大きい。従来、溶融めっきフェラ
イト系ステンレス鋼は、主として軽加工の部材に用いら
れることを期待して製造されたものである。しかし、簡
単な曲げ加工でも割れが生ずるため、例え割れのない状
態で使用されたとしても、石がぶつかるなどの頻繁に起
こり得る軽度の事故によって破壊が生ずる危険性を払拭
できず、広範に使用されることはなかった。このような
場合、従来Niを多量に含んだオーステナイト系ステン
レス鋼をめっき原板とした溶融めっきオーステナイト系
ステンレス鋼が用いられてきた。本発明により、溶融め
っきフェライト系ステンレス鋼の曲げ加工性が向上し、
しかも簡単な事故でも懸念された破壊の危険性が解消し
たため、Niを含む高価な溶融めっきオーステナイト系
ステンレス鋼板の必要がなくなる。特に屋根材では、熱
膨張率の低い溶融めっきフェライト系ステンレス鋼が使
用できるため、構造体としての設計も容易になった。こ
のように、本発明により間接的に得られる経済的な効果
も大きい。According to the present invention, it has become possible to produce a hot-dip coated ferritic stainless steel sheet having excellent bending workability. Conventionally, products with poor bending workability had to be reduced in yield, but the present invention increases product yield,
The industrial benefits are huge. Conventionally, hot-dip ferritic stainless steel has been manufactured mainly with the expectation that it will be used for light-worked members. However, even a simple bending process causes cracks, so even if it is used without cracks, it cannot be wiped out the risk of destruction due to frequent minor accidents such as hitting stones, so it is widely used It was never done. In such a case, hot-dip galvanized austenitic stainless steel using an austenitic stainless steel containing a large amount of Ni as a plating base plate has conventionally been used. According to the present invention, the bending workability of hot-dip ferritic stainless steel is improved,
Moreover, since the risk of destruction, which has been concerned even in a simple accident, has been eliminated, the need for expensive hot-dip austenitic stainless steel sheets containing Ni is eliminated. Particularly, for roofing materials, hot-dip galvanized ferritic stainless steel having a low coefficient of thermal expansion can be used. Thus, the economic effect obtained indirectly by the present invention is also large.
【図1】めっきステンレス鋼板のめっき部分の断面を示
す模式図。FIG. 1 is a schematic view showing a cross section of a plated portion of a plated stainless steel plate.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 平松 博之 福岡県北九州市戸畑区飛幡町1番1号 新日本製鐵株式会社 八幡製鐵所内 (72)発明者 田野 和広 福岡県北九州市戸畑区飛幡町1番1号 新日本製鐵株式会社 八幡製鐵所内 (56)参考文献 特開 平6−316753(JP,A) (58)調査した分野(Int.Cl.7,DB名) C23C 2/00 - 2/40 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Hiroyuki Hiramatsu 1-1-1, Hibata-cho, Tobata-ku, Kitakyushu-shi, Fukuoka Nippon Steel Corporation Yawata Works (72) Inventor Kazuhiro Tano Tobata-ku, Tobata-ku, Kitakyushu-shi, Fukuoka No. 1-1, Nippon Steel Corporation Yawata Works (56) References JP-A-6-316753 (JP, A) (58) Fields investigated (Int. Cl. 7 , DB name) C23C 2 / 00-2/40
Claims (10)
溶融めっき層との境界面に、前記ステンレス鋼と溶融め
っき金属との合金層が面積率で少なくとも60%以上存
在し、かつめっき鋼板表面に垂直な任意の断面から見て
前記合金層厚みの50%以上の長さを有する微細な亀裂
を被めっき鋼板表面に平行な長さ1mm当たり50本以上
前記合金層中に有することを特徴とする曲げ加工性に優
れた溶融めっきフェライト系ステンレス鋼板。At least 60% or more of the alloy layer of the stainless steel and the hot-dip metal is present at the interface between the ferritic stainless steel-coated steel sheet and the hot-dip coating layer, and is perpendicular to the surface of the hot-dip steel sheet. Bending characterized by having at least 50 fine cracks having a length of 50% or more of the thickness of the alloy layer as viewed from an arbitrary cross section per 1 mm length parallel to the surface of the steel sheet to be plated. Hot-dip ferritic stainless steel sheet with excellent resistance.
テンレス被めっき鋼板と溶融めっき層との境界面に、前
記ステンレス鋼と溶融めっき金属との合金層が面積率で
少なくとも60%以上存在し、かつめっき鋼板表面に垂
直な任意の断面から見て前記合金層厚みの50%以上の
長さを有する微細な亀裂を被めっき鋼板表面に平行な長
さ1mm当たり50本以上前記合金層中に有することを特
徴とする曲げ加工性に優れた溶融めっきフェライト系ス
テンレス鋼板。2. The composition contains C: 0.08% or less, Si: 1.0% or less, Mn: 1.0% or less, Cr: 11 to 25%, and N: 0.03% or less by weight%. An alloy layer of the stainless steel and the hot-dip metal is present at an interface of at least 60% or more at an interface between the hot-dip layer and the ferritic stainless steel-plated steel sheet whose balance is composed of Fe and unavoidable impurities, and the surface of the coated steel sheet A fine crack having a length of 50% or more of the thickness of the alloy layer as viewed from an arbitrary cross section perpendicular to the surface of the alloy layer. Hot-dip ferritic stainless steel sheet with excellent bending workability.
避不純物からなるフェライト系ステンレス被めっき鋼板
と溶融めっき層との境界面に、前記ステンレス鋼と溶融
めっき金属との合金層が面積率で少なくとも60%以上
存在し、かつめっき鋼板表面に垂直な任意の断面から見
て前記合金層厚みの50%以上の長さを有する微細な亀
裂を被めっき鋼板表面に平行な長さ1mm当たり50本以
上前記合金層中に有することを特徴とする曲げ加工性に
優れた溶融めっきフェライト系ステンレス鋼板。C .: 0.08% or less by weight, C: 1.0% or less, Mn: 1.0% or less, Cr: 11 to 25%, N: 0.03% or less by weight%, Further, it contains one or more of Nb: 1.5% or less, Ti: 0.5% or less, Mo: 2.5% or less, Cu: 0.5% or less, with the balance being Fe and unavoidable impurities. An alloy layer of the stainless steel and the hot-dip metal is present at an area ratio of at least 60% or more at the interface between the ferritic stainless steel-plated steel sheet and the hot-dip coating layer, and from any cross section perpendicular to the surface of the coated steel sheet. It is characterized by having at least 50 fine cracks having a length of at least 50% of the thickness of the alloy layer in the alloy layer per 1 mm in length parallel to the surface of the steel sheet to be plated, and having excellent bending workability. Hot-dip ferritic stainless steel sheet.
属またはAlを主成分とする金属であることを特徴とす
る請求項1,2あるいは3のそれぞれに記載の曲げ加工
性に優れた溶融めっきステンレス鋼板。4. A hot-dip plating metal whose main component is Zn.
Metal or a metal mainly composed of Al
4. The bending process according to claim 1, 2, or 3.
Hot-dip coated stainless steel sheet with excellent resistance .
溶融めっき層との境界面に、前記ステンレス鋼と溶融め
っき金属との合金層が面積率で少なくとも60%以上存
在する溶融めっきを施した後、被めっき鋼板と溶融めっ
き金属との合金層に、最大伸び率0.1%以上を加える
ことによって、被めっきステンレス鋼板表面に垂直な任
意の断面から見て前記合金層厚みの50%以上の長さを
有する微細な亀裂を被めっき鋼板表面に平行な長さ1mm
当たり50本以上前記合金層中に存在させることを特徴
とする曲げ加工性に優れた溶融めっきフェライト系ステ
ンレス鋼板の製造法。5. A hot-dip coating method in which an alloy layer of the stainless steel and the hot-dip metal is present on the interface between the ferritic stainless steel-coated steel sheet and the hot-dip coating layer in an area ratio of at least 60% or more. By adding a maximum elongation of 0.1% or more to the alloy layer of the plated steel sheet and the hot-dip metal, a length of 50% or more of the alloy layer thickness as viewed from any cross section perpendicular to the surface of the stainless steel plate to be plated. 1mm length parallel to the surface of the steel plate to be plated
A method for producing a hot-dip-coated ferritic stainless steel sheet having excellent bending workability, characterized in that 50 or more steel sheets are present in the alloy layer.
溶融めっき層との境界面に、前記ステンレス鋼と溶融め
っき金属との合金層が面積率で少なくとも60%以上存
在する溶融めっきを施し、350〜400℃の温度に5
時間以上保定した後、被めっき鋼板と溶融めっき金属と
の合金層に、最大伸び率0.1%以上を加えることによ
って、被めっき鋼板表面に垂直な任意の断面から見て前
記合金層厚みの50%以上の長さを有する微細な亀裂を
被めっき鋼板表面に平行な長さ1mm当たり50本以上前
記合金層中に存在させることを特徴とする曲げ加工性に
優れた溶融めっきフェライト系ステンレス鋼板の製造
法。6. Hot-dip coating is performed on the interface between the ferritic stainless steel-plated steel sheet and the hot-dip coating layer so that the alloy layer of the stainless steel and the hot-dip metal is present in an area ratio of at least 60% or more. 5 degrees Celsius
After holding for more than an hour, by adding a maximum elongation of 0.1% or more to the alloy layer of the steel sheet to be plated and the hot-dip metal, the thickness of the alloy layer as viewed from any cross section perpendicular to the surface of the steel sheet to be plated A hot-plated ferritic stainless steel sheet excellent in bending workability, characterized in that at least 50 fine cracks having a length of 50% or more are present in the alloy layer per 1 mm in length parallel to the surface of the steel sheet to be plated. Manufacturing method.
テンレス被めっき鋼板と溶融めっき層との境界面に、前
記ステンレス鋼と溶融めっき金属との合金層が面積率で
少なくとも60%以上存在する溶融めっきを施し、35
0〜400℃の温度に5時間以上保定した後、被めっき
鋼板と溶融めっき金属との合金層に、最大伸び率0.1
%以上を加えることによって、めっき鋼板表面に垂直な
任意の断面から見て前記合金層厚みの50%以上の長さ
を有する微細な亀裂を被めっき鋼板表面に平行な長さ1
mm当たり50本以上前記合金層中に存在させることを特
徴とする曲げ加工性に優れた溶融めっきフェライト系ス
テンレス鋼板の製造法。7. The composition contains C: 0.08% or less, Si: 1.0% or less, Mn: 1.0% or less, Cr: 11 to 25%, and N: 0.03% or less by weight%. Is subjected to hot-dip plating in which an alloy layer of the stainless steel and the hot-dip plating metal is present in an area ratio of at least 60% or more at the interface between the ferritic stainless steel-plated steel sheet comprising Fe and unavoidable impurities and the hot-dip coating layer;
After maintaining at a temperature of 0 to 400 ° C. for 5 hours or more, the alloy layer of the steel sheet to be plated and the hot-dip metal is coated with a maximum elongation of 0.1%.
% Or more, a fine crack having a length of 50% or more of the thickness of the alloy layer as viewed from an arbitrary cross section perpendicular to the surface of the coated steel sheet has a length 1 parallel to the surface of the steel sheet to be plated.
A method for producing a hot-dip coated ferritic stainless steel sheet having excellent bending workability, characterized in that 50 or more per mm are present in the alloy layer.
避不純物からなるフェライト系ステンレス被めっき鋼板
と溶融めっき層との境界面に、前記ステンレス鋼と溶融
めっき金属との合金層が面積率で少なくとも60%以上
存在する溶融めっきを施し、350〜400℃の温度に
5時間以上保定した後、被めっき鋼板と溶融めっき金属
との合金層に、最大伸び率0.1%以上を加えることに
よって、めっき鋼板表面に垂直な任意の断面から見て前
記合金層厚みの50%以上の長さを有する微細な亀裂を
被めっき鋼板表面に平行な長さ1mm当たり50本以上前
記合金層中に存在させることを特徴とする曲げ加工性に
優れた溶融めっきフェライト系ステンレス鋼板の製造
法。8. The composition contains C: 0.08% or less, Si: 1.0% or less, Mn: 1.0% or less, Cr: 11 to 25%, and N: 0.03% or less by weight%. Further, it contains one or more of Nb: 1.5% or less, Ti: 0.5% or less, Mo: 2.5% or less, Cu: 0.5% or less, with the balance being Fe and unavoidable impurities. Hot-dip plating in which an alloy layer of the stainless steel and the hot-dip plating metal is present in an area ratio of at least 60% or more at a boundary surface between the ferritic stainless steel-plated steel sheet and the hot-dip coating layer at a temperature of 350 to 400 ° C. After holding for 5 hours or more, by adding a maximum elongation of 0.1% or more to the alloy layer of the steel sheet to be plated and the hot-dip metal, the thickness of the alloy layer as viewed from an arbitrary cross section perpendicular to the surface of the coated steel sheet is increased. Fine turtle with a length of 50% or more A method for producing a hot-dip galvanized ferritic stainless steel sheet excellent in bending workability, characterized in that 50 or more cracks are present in the alloy layer per 1 mm length parallel to the surface of the steel sheet to be plated.
して、スキンパス圧延、半径100mm以下のロールを1
本以上通過させるベンディング型レベラー矯正、テンシ
ョン型レベラー矯正の1種または2種以上を施すことを
特徴とする請求項5,6,7あるいは8のそれぞれに記
載の曲げ加工性に優れた溶融めっきステンレス鋼板の製
造法。9. As means for adding a maximum elongation of 0.1% or more, skin pass rolling, a roll having a radius of 100 mm or less is used.
Bending type leveler straightening passing the above hot dipping stainless with excellent bending workability as claimed in each of claims 5, 6, 7 or 8, characterized by applying one or more of the tension-type leveler straightening Steel sheet manufacturing method.
金属またはAlを主成分とする金属であることを特徴と
する請求項5,6,7あるいは8のそれぞれに記載の曲
げ加工性に優れた溶融めっきステンレス鋼板の製造法。10. An excellent bending workability according to claim 5 , wherein the hot-dip plating metal is a metal mainly composed of Zn or a metal mainly composed of Al. preparation of hot dipping stainless steel plate was.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP13688895A JP3202539B2 (en) | 1995-03-27 | 1995-06-02 | Hot-dip ferritic stainless steel sheet excellent in bending workability and method for producing the same |
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP7-68413 | 1995-03-27 | ||
JP6841395 | 1995-03-27 | ||
JP13688895A JP3202539B2 (en) | 1995-03-27 | 1995-06-02 | Hot-dip ferritic stainless steel sheet excellent in bending workability and method for producing the same |
Publications (2)
Publication Number | Publication Date |
---|---|
JPH08325697A JPH08325697A (en) | 1996-12-10 |
JP3202539B2 true JP3202539B2 (en) | 2001-08-27 |
Family
ID=26409637
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Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP13688895A Expired - Lifetime JP3202539B2 (en) | 1995-03-27 | 1995-06-02 | Hot-dip ferritic stainless steel sheet excellent in bending workability and method for producing the same |
Country Status (1)
Country | Link |
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JP (1) | JP3202539B2 (en) |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP3307312B2 (en) * | 1998-01-06 | 2002-07-24 | 住友金属工業株式会社 | Method for producing alloyed hot-dip galvanized steel sheet with excellent low-temperature chipping resistance and workability |
JP4510320B2 (en) * | 2001-04-19 | 2010-07-21 | 新日本製鐵株式会社 | Hot-dip aluminized steel sheet with excellent corrosion resistance after processing and manufacturing method thereof |
KR102177521B1 (en) * | 2016-05-30 | 2020-11-11 | 제이에프이 스틸 가부시키가이샤 | Ferritic stainless steel sheet |
-
1995
- 1995-06-02 JP JP13688895A patent/JP3202539B2/en not_active Expired - Lifetime
Also Published As
Publication number | Publication date |
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JPH08325697A (en) | 1996-12-10 |
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