JP3091418B2 - Hot rolled stainless steel sheet and method for producing the same - Google Patents
Hot rolled stainless steel sheet and method for producing the sameInfo
- Publication number
- JP3091418B2 JP3091418B2 JP08259318A JP25931896A JP3091418B2 JP 3091418 B2 JP3091418 B2 JP 3091418B2 JP 08259318 A JP08259318 A JP 08259318A JP 25931896 A JP25931896 A JP 25931896A JP 3091418 B2 JP3091418 B2 JP 3091418B2
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- Prior art keywords
- hot
- scale
- rolled
- stainless steel
- steel sheet
- Prior art date
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- Heat Treatment Of Sheet Steel (AREA)
- Heat Treatment Of Steel (AREA)
- Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)
Description
【0001】[0001]
【発明の属する技術分野】本発明は、熱延ステンレス鋼
板およびその製造方法に関し、詳しくは、酸洗などのス
ケール除去工程を省略して加工を施すのに好適な、ある
いは酸洗時の脱スケール性さらには脱スケール後の表面
性状に優れる熱延ステンレス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-rolled stainless steel sheet and a method for producing the same, and more particularly, to a method suitable for performing processing by omitting a scale removing step such as pickling, or descaling during pickling. TECHNICAL FIELD The present invention relates to a hot-rolled stainless steel sheet having excellent surface properties after descaling and a method for producing the same.
【0002】[0002]
【従来の技術】ステンレス鋼はCrやNiなどの合金元素を
多量に含有させて普通鋼に比べ著しく耐食性を高めた材
料であり、一般には、連続鋳造により精錬した溶鋼を凝
固させて鋼スラブとなし、この鋼スラブを1100〜1300℃
程度に加熱後熱間圧延して熱延鋼板(その時々の状態に
より熱延鋼帯、熱延コイルともいう)となし、この熱延
鋼板を連続的あるいはバッチ的に焼鈍し、さらに硫酸槽
および硝酸・弗酸混酸槽を通して酸洗した後、冷間圧延
して冷延鋼板(その時々の状態により冷延鋼帯、冷延コ
イルともいう)となし、この冷延鋼板をさらに焼鈍−酸
洗するという工程で製造される。2. Description of the Related Art Stainless steel is a material that contains a large amount of alloying elements such as Cr and Ni and has a significantly higher corrosion resistance than ordinary steel. In general, stainless steel is formed by solidifying molten steel refined by continuous casting to form a steel slab. None, this steel slab is 1100-1300 ℃
After being heated to a degree, hot rolling is performed to form a hot-rolled steel sheet (also referred to as a hot-rolled steel strip or hot-rolled coil depending on the state at that time). The hot-rolled steel sheet is annealed continuously or batchwise, and further, a sulfuric acid bath and After pickling through a nitric acid / hydrofluoric acid mixed acid bath, it is cold-rolled to form a cold-rolled steel sheet (also referred to as a cold-rolled steel strip or a cold-rolled coil depending on the state at that time). This cold-rolled steel sheet is further annealed and pickled. It is manufactured in the process of doing.
【0003】通常は冷延鋼板を各種用途に供するが、熱
延後の焼鈍−酸洗鋼板を冷延せずそのまま供用する場合
もある。ステンレス鋼においては、Crを多量に含有する
ことから熱間圧延時に表面に(Fe,Cr)2O3や(Fe,Cr)3O4を
主体とした Fe-Cr系酸化層が、さらに鋼中のSiによりこ
の Fe-Cr系酸化層と地金との界面にSiO2からなる中間酸
化層が形成される。これらの酸化層(スケール)を有し
たままの熱延鋼板を焼鈍後に冷間圧延すると、圧延中に
スケールが剥離して冷延ロールを傷めるほか圧延材に噛
み込んで表面欠陥の原因となる。[0003] Usually, cold-rolled steel sheets are used for various applications, but in some cases, annealed-pickled steel sheets after hot rolling are used without being cold-rolled. Since stainless steel contains a large amount of Cr, a Fe-Cr-based oxide layer mainly composed of (Fe, Cr) 2 O 3 and (Fe, Cr) 3 O 4 An intermediate oxide layer of SiO 2 is formed at the interface between the Fe-Cr-based oxide layer and the base metal by the Si inside. If a hot-rolled steel sheet having such an oxide layer (scale) is annealed and then cold-rolled, the scale peels off during the rolling and damages the cold-rolled rolls, and causes bites in the rolled material to cause surface defects.
【0004】かかる有害なスケールを除去するために熱
延後に酸洗工程が設けられるのであるが、ステンレス鋼
に特有の前記組成のスケールは、非常に緻密であって酸
洗脱スケール性(酸洗性)が悪いことから酸洗ラインを
律速し生産性を阻害する。そこで酸洗負荷を軽減して酸
洗のスピードアップを図るために、鋼板表面に鋼球や砂
等の硬質微粒(ショット粒)を高圧噴射してスケールに
クラックを導入するいわゆるショットブラスト処理が従
来広く行われている。しかし、ショットブラストされた
鋼板表面にはショット目と呼ばれる凹凸が刻まれ、表面
粗度が大きくなり、表面品質が冷延鋼板のレベルに達し
ない。そのため、比較的安価な熱延ステンレス鋼酸洗板
を冷延鋼板の代替品として広く供給できないという問題
がある。[0004] To remove such harmful scales, a pickling step is provided after hot rolling. However, the scale having the above-mentioned composition peculiar to stainless steel is very dense and has a pickling descalability (pickling). ), The rate of the pickling line is limited and productivity is impaired. To reduce the pickling load and increase the speed of pickling, so-called shot blasting, in which hard fine particles (shot particles) such as steel balls or sand are injected at high pressure onto the steel sheet surface to introduce cracks into the scale, has been conventionally used. Widely used. However, irregularities called shots are formed on the surface of the steel plate subjected to the shot blasting, the surface roughness increases, and the surface quality does not reach the level of the cold rolled steel plate. Therefore, there is a problem that a relatively inexpensive hot-rolled stainless steel pickled plate cannot be widely supplied as a substitute for a cold-rolled steel plate.
【0005】もう一つの酸洗負荷軽減策としてはスケー
ルの薄層化が指向され、熱延工程でのスケール生成を抑
制する技術として、例えば特開昭58-53323号公報、特開
昭59-97710号公報、特開昭61-123403 号公報等に開示さ
れるように、熱間圧延の最終圧延機出側から巻取機まで
の区間に、内部を不活性または還元性ガス雰囲気に制御
できるボックスを設け、圧延後の熱延鋼帯が該ボックス
内を通過できるように構成する方法が知られている。Another measure for reducing the pickling load is to reduce the thickness of the scale. Techniques for suppressing scale formation in the hot rolling process include, for example, JP-A-58-53323 and JP-A-59-53323. No. 97710, as disclosed in Japanese Patent Application Laid-Open No. 61-123403, etc., in the section from the exit side of the final rolling mill to the winder of hot rolling, the inside can be controlled to an inert or reducing gas atmosphere. A method is known in which a box is provided so that a hot-rolled steel strip after rolling can pass through the box.
【0006】これは、熱間圧延の各パスでそれ以前に生
成したスケールは除去され、巻取後に残るのは最終パス
後に生成したスケールのみであって、最終圧延機出側か
ら巻取機までの鋼帯通過区間を無酸化性雰囲気に維持し
て当該区間でのスケール生成を防止すればスケール厚が
抑制できるという技術思想に基づく。しかし、この方法
は、最終圧延機出側から巻取機に至る長大な区間全域を
ガスシールして大量のガスを供給しなければならないた
め実用的でない。[0006] This is because the scale generated before each pass of the hot rolling is removed, and only the scale generated after the final pass remains after winding, and the scale from the final rolling mill discharge side to the winder is removed. Is based on the technical idea that the scale thickness can be suppressed by maintaining the steel strip passing section in a non-oxidizing atmosphere to prevent scale formation in the section. However, this method is not practical because a large amount of gas must be supplied by gas-sealing the entire long section from the exit side of the final rolling mill to the winding machine.
【0007】また、上記以外の薄スケール化技術とし
て、例えば特開平4-238620号公報に、熱間仕上げ圧延前
に高圧水を特定範囲の衝突圧で鋼帯表面に噴射するとい
うデスケーリング方法が提案されている。しかし、この
方法をステンレス鋼に適用すると、仕上げ圧延ロール面
と鋼帯表面とで金属同士が焼き付いて表面欠陥の原因と
なる。As a thinning technique other than the above, for example, Japanese Patent Application Laid-Open No. Hei 4-238620 discloses a descaling method in which high-pressure water is sprayed onto a steel strip surface at a specific range of collision pressure before hot finish rolling. Proposed. However, when this method is applied to stainless steel, the metal is seized between the finish rolling roll surface and the steel strip surface, causing surface defects.
【0008】また、光沢等の表面特性が重視されない用
途向けの熱延ステンレス鋼板にあっては、スケール付き
のまま使用できれば酸洗工程を省略できて大幅なコスト
ダウンが期待できるのであるが、従来の工程で製造され
たスケール付き熱延ステンレス鋼板は、これに金型で曲
げ・絞り等の加工を施すと、スケールが部分的に剥離し
て、金型寿命を低下させたり、剥離した粉塵によって作
業環境が悪化するという問題がある。Further, in the case of a hot-rolled stainless steel sheet for applications where surface characteristics such as glossiness are not important, if it can be used with a scale, it is possible to omit the pickling step and to expect a significant cost reduction. When a hot-rolled stainless steel sheet with a scale manufactured in the step is subjected to processing such as bending and drawing with a mold, the scale is partially peeled off, shortening the mold life, and There is a problem that the working environment deteriorates.
【0009】[0009]
【発明が解決しようとする課題】この発明の目的は、上
記従来技術の問題を解決し、スケール付きのまま加工し
ても剥離・発塵しないレベルのスケール密着性を備え、
また、酸洗前のショットブラスト処理を必要としないレ
ベルの酸洗性を備えた熱延ステンレス鋼板およびその製
造方法を提供することにある。SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art, and to provide a level of scale adhesion that does not peel or generate dust even when processed with a scale.
Another object of the present invention is to provide a hot-rolled stainless steel sheet having a level of pickling property that does not require a shot blast treatment before pickling, and a method for producing the same.
【0010】[0010]
【課題を解決するための手段】本発明者らは上記目的の
実現に向けて、スケール付き熱延ステンレス鋼板のスケ
ール構造が該熱延ステンレス鋼板の加工時のスケール密
着性(換言すれば剥離性)および酸洗性に及ぼす影響、
ならびに前記スケール構造と熱延条件との関係について
鋭意実験・検討を重ねた。その結果、特定組成でかつ特
定スケール構造の熱延ステンレス鋼板が上記要請を満足
する特性を具有し、当該熱延ステンレス鋼板は特定の熱
延条件下で得られるという新規な知見を得るに至り、か
かる知見に基づいて次に述べる本発明を完成した。Means for Solving the Problems To achieve the above object, the inventors of the present invention have developed a scale structure of a hot-rolled stainless steel sheet with a scale having a scale adhesion (in other words, peeling property) at the time of processing the hot-rolled stainless steel sheet. ) And its effect on pickling,
In addition, intensive experiments and examinations were repeated on the relationship between the scale structure and the hot rolling conditions. As a result, a hot rolled stainless steel sheet having a specific composition and a specific scale structure has characteristics satisfying the above requirements, and the hot rolled stainless steel sheet leads to a new finding that it can be obtained under specific hot rolling conditions. Based on such knowledge, the present invention described below has been completed.
【0011】本発明は、Crを10wt%以上含有し、表層の
スケール厚さが 2.5μm 以下であることを特徴とする熱
延ステンレス鋼板であり、好ましくは、さらに、Siを
1.0wt%以下含有するとともにスケール層と下地合金と
の界面に形成される含Si酸化物層の厚さを 0.1μm 以下
とすることを特徴とする熱延ステンレス鋼板である。上
記本発明に係る熱延ステンレス鋼板は、Crを10wt%以
上、好ましくはSiを 1.0wt%以下、含有するスラブを熱
間圧延して鋼帯コイルとする熱延ステンレス鋼板の製造
方法において、下記に定義される展伸比が 150以上とな
るように熱間圧延することを要旨とする。The present invention is a hot-rolled stainless steel sheet containing 10 wt% or more of Cr and having a scale thickness of a surface layer of 2.5 μm or less.
A hot-rolled stainless steel sheet containing 1.0 wt% or less and having a thickness of a Si-containing oxide layer formed at an interface between a scale layer and a base alloy of 0.1 μm or less. The above-described hot-rolled stainless steel sheet according to the present invention is a hot-rolled stainless steel sheet producing a steel strip coil by hot rolling a slab containing 10 wt% or more of Cr, preferably 1.0 wt% or less of Si. It is the gist that hot rolling is performed so that the elongation ratio defined in the above becomes 150 or more.
【0012】記 展伸比=(鋼帯コイルの圧延面の面積)/(スラブの圧
延面の面積)[0012] Elongation / ratio = (area of rolled surface of steel strip coil) / (area of rolled surface of slab)
【0013】[0013]
【発明の実施の形態】本発明の熱延ステンレス鋼板は、
Crを10wt%以上含有し、表層のスケール厚さが 2.5μm
以下であるがゆえに、とくに加工時のスケール密着性に
優れるものである。本発明者らは、スケール密着性の良
好な熱延ステンレス鋼板を得るべく多くの実験を重ね、
従来にないスケール厚さ 2.5μm 以下のスケール構造を
有する熱延ステンレス鋼板においてスケール密着性が格
段に高い値を示すことを新たに知見した。BEST MODE FOR CARRYING OUT THE INVENTION The hot-rolled stainless steel sheet of the present invention
Contains Cr at 10wt% or more, and the surface scale thickness is 2.5μm
Because of the following, it is particularly excellent in scale adhesion during processing. The present inventors have repeated many experiments to obtain a hot-rolled stainless steel sheet with good scale adhesion,
We have newly found that scale adhesion shows a remarkably high value in a hot-rolled stainless steel sheet having a scale structure with an unprecedented scale thickness of 2.5 μm or less.
【0014】すなわち加工時にスケールが剥離しないた
めには、表層スケール厚さが2.5 μm以下であることが
必須である。ただし、ステンレス鋼においてCr含有量が
10wt%未満の場合、鋼スラブを1100〜1300℃程度に加熱
後粗圧延、仕上圧延し、600〜1050℃で巻き取る一般的
な熱間圧延方法で展伸比≧150 として製造された熱延コ
イル製品では、2.5 μm以下の厚さのスケール構造を得
ることが困難であるだけでなく、ステンレス鋼が本来備
えるべき耐食性が不十分なものとなるため、Cr含有量を
10wt%以上に制限する。なお、スケール厚さは薄いほど
好ましいので下限を設ける特段の理由はない。また、Cr
含有量の上限については、通常のステンレス鋼のCr含有
量の上限(20wt%程度)としておけばよい。That is, in order for the scale not to peel off during processing, the thickness of the surface layer scale must be 2.5 μm or less. However, the Cr content in stainless steel
If less than 10wt% , heat the steel slab to about 1100-1300 ℃
After rough rolling, finish rolling and winding at 600 to 1050 ° C
Hot rolled steel manufactured with an elongation ratio ≥150 by a simple hot rolling method
It is not only difficult to obtain a scale structure with a thickness of 2.5 μm or less, but also the corrosion resistance that stainless steel should originally have is insufficient.
Limit to 10 wt% or more. There is no particular reason for setting the lower limit because the smaller the scale thickness, the better. Also, Cr
The upper limit of the content may be set as the upper limit (about 20 wt%) of the Cr content of ordinary stainless steel.
【0015】本発明の熱延ステンレス鋼板は、さらに、
Siを 1.0wt%以下含有するとともにスケール層と下地合
金との界面に形成される含Si酸化物層の厚さを 0.1μm
以下とすることが好ましい。この熱延ステンレス鋼板
は、加工時の密着性に優れると同時に、優れた酸洗脱ス
ケール性(酸洗性)を備えたものとなる。本発明者ら
は、熱延ステンレス鋼板の酸洗性支配要因を見出すべく
鋭意検討した結果、酸洗性が、表層スケールと下地合金
との界面に形成された含Si酸化物層(SiO2層と考えられ
る) の厚さに大きく依存し、この厚さが 0.1μm を超え
ると酸洗性が著しく悪化して酸洗前にショットブラスト
処理等の機械的スケール除去を施す必要があるが、 0.1
μm 以下であればその必要がない程に酸洗性が向上する
ことがわかった。すなわち、酸洗前の機械的スケール除
去を要さずそのため例えばショット目が刻まれず酸洗後
の表面品質に優れる熱延ステンレス鋼板を得るには、前
記含Si酸化物層の厚さが 0.1μm 以下であることが好ま
しい。The hot-rolled stainless steel sheet of the present invention further comprises:
Contain not more than 1.0 wt% of Si, and reduce the thickness of the Si-containing oxide layer formed at the interface between the scale layer and the base alloy by 0.1 μm
It is preferable to set the following. This hot-rolled stainless steel sheet has excellent adhesiveness during processing and, at the same time, has excellent pickling descaling properties (pickling properties). The present inventors have conducted intensive studies to find out the controlling factors of the pickling property of a hot-rolled stainless steel sheet. As a result, the pickling property was found to be higher than that of the Si-containing oxide layer (SiO 2 layer) formed at the interface between the surface scale and the base alloy. When the thickness exceeds 0.1 μm, the pickling properties deteriorate significantly and it is necessary to remove mechanical scale such as shot blasting before pickling.
It was found that the pickling property was improved to the extent that it was not required to be less than μm. In other words, in order to obtain a hot-rolled stainless steel sheet that does not require mechanical scale removal before pickling and therefore has excellent surface quality after pickling without cutting, for example, the thickness of the Si-containing oxide layer is 0.1 μm. The following is preferred.
【0016】しかし、下地合金中のSi含有量が1.0 wt%
を超えると、鋼スラブを1100〜1300℃程度に加熱後粗圧
延、仕上圧延し、600 〜1050℃で巻き取る一般的な熱間
圧延方法でCr含有量≧10wt%、展伸比≧150 として製造
された熱延コイル製品では、含Si酸化物層の厚さが大き
くなって0.1 μmを超えてしまうため鋼中Si含有量は1.
0 wt%以下とする。なお、含Si酸化物層の厚さは薄いほ
ど好ましいため特に下限を設ける必要はない。他方、Si
は鋼の脱酸に有効なほか高温での耐酸化性を向上させる
有効な元素であって比較的重要であるため、鋼中に0.1
wt%程度以上は含むことが好ましい。However, when the Si content in the base alloy is 1.0 wt%
Above, the steel slab is heated to about 1100-1300 ° C and then
General hot rolling, finishing and rolling at 600 to 1050 ° C
Manufactured by rolling method with Cr content ≧ 10 wt%, elongation ratio ≧ 150
In the hot-rolled coil products thus manufactured, the thickness of the Si-containing oxide layer was so large that it exceeded 0.1 μm, so the Si content in steel was 1.
0 wt% or less. Note that the lower the thickness of the Si-containing oxide layer, the better. On the other hand, Si
Is an element that is effective for deoxidation of steel and improves oxidation resistance at high temperatures and is relatively important.
It is preferable to contain about wt% or more.
【0017】ステンレス鋼中の成分元素としては、Cr、
Si以外に、耐食性向上元素のNiさらにはCu, Mo、鋼中S
固定元素のMn、脱酸元素のAl、それにC,N固定元素の
Ti,Nb, Zr, V等々が添加されることが多いが、これら
の成分は常法に沿って添加すればよく、それぞれの含有
量は本発明において特に限定されない。上記本発明の熱
延ステンレス鋼板は、Crを10wt%以上、好ましくはSiを
1.0wt%以下、含有するスラブを熱間圧延して鋼帯コイ
ルとする熱延ステンレス鋼板の製造方法において、展伸
比〔=(鋼帯コイルの圧延面の面積)/(スラブの圧延
面の面積)〕が 150以上となるように熱間圧延すること
により製造できる。The constituent elements in stainless steel include Cr,
In addition to Si, corrosion-resistant elements such as Ni, Cu, Mo, and S in steel
Fixed element Mn, deoxidized element Al, and C, N fixed element
Ti, Nb, Zr, V, and the like are often added, but these components may be added according to a conventional method, and the contents of the respective components are not particularly limited in the present invention. The hot-rolled stainless steel sheet of the present invention contains Cr in an amount of 10 wt% or more, preferably Si.
In a method for producing a hot-rolled stainless steel sheet in which a slab containing not more than 1.0 wt% is hot-rolled to form a steel strip coil, the expansion ratio [= (the area of the rolled surface of the steel strip coil) / (the Area)] is 150 or more.
【0018】この理由の詳細は明らかではないが、表層
スケール厚さが 2.5μm 以下に抑制される点について
は、展伸比の大きい熱延条件では表面スケールも展伸
し、圧延が進むにつれて薄くなることに加え、これまで
行われていなかった 150以上という大きい展伸比で熱延
することにより、熱延後期に部分的にスケールに亀裂が
発生し、亀裂発生部分に新たに露呈した下地合金面に新
たにスケールが生成し、この新生スケールが最終的に亀
裂前のスケールよりもさらに薄くなるためと考えられ
る。Although the details of this reason are not clear, the point that the surface scale thickness is suppressed to 2.5 μm or less is that the surface scale also expands under hot rolling conditions with a large expansion ratio, and becomes thinner as rolling progresses. In addition to this, the base alloy was exposed to a large scale at a large elongation ratio of 150 or more, which had not been done before, causing cracks to partially occur in the scale in the latter half of hot rolling and newly exposing to the crack initiation part It is considered that a new scale is generated on the surface, and the new scale eventually becomes thinner than the scale before the crack.
【0019】また、含Si酸化物層の厚さが 0.1μm 以下
に抑制される点について、発明者らは実験を行い、含Si
酸化物層はスラブ加熱中あるいは熱延初期(粗圧延中)
の温度である1100℃以上の高温で生成・成長するが、熱
延後期(仕上げ圧延中)の温度域(概ね 600〜1050℃)
ではほとんど生成しないという知見を得ており、このこ
とから、巻き取り後にこのように薄い含Si酸化物層が存
在するのは、初期の含Si酸化物層が前記同様に展伸され
て薄くなることに加え、熱延後期に生じる前記亀裂部分
に露呈した下地合金面に新たな含Si酸化物層が生成し難
くなるためと考えられる。The inventors conducted experiments on the point that the thickness of the Si-containing oxide layer was suppressed to 0.1 μm or less, and
Oxide layer during slab heating or early in hot rolling (during rough rolling)
Temperature of 1100 ° C or higher, but the temperature range in the latter half of hot rolling (during finish rolling) (generally 600 to 5050 ° C)
It has been found that almost no silicon oxide is formed, and from this, the existence of such a thin Si-containing oxide layer after winding is because the initial Si-containing oxide layer is expanded and thinned as described above. In addition, it is considered that a new Si-containing oxide layer is less likely to be generated on the surface of the underlying alloy exposed to the cracks generated in the latter half of hot rolling.
【0020】なお、展伸比の上限は、熱間圧延設備の圧
延能力の許す範囲であるならば良く特に規制されない。The upper limit of the stretching ratio is not particularly limited as long as it is within the range of the rolling capacity of the hot rolling equipment.
【0021】[0021]
【実施例】表1に示す成分のステンレス鋼スラブを、表
2に示す種々の厚さに調え同表に示す種々の展伸比で熱
間圧延してコイルに巻き取り、同表に示す種々の熱延仕
上げ板厚の熱延板を得た。スラブ加熱温度は鋼Aでは11
50℃、鋼Bでは1200℃、鋼C,DおよびEでは1100℃と
し、コイル巻取温度はいずれも 800℃とした。EXAMPLES Stainless steel slabs having the components shown in Table 1 were adjusted to various thicknesses shown in Table 2, hot-rolled at various expansion ratios shown in the table, wound up into coils, and various types shown in the table. Hot-rolled sheet having a hot-rolled finished sheet thickness of Slab heating temperature is 11 for steel A
The temperature was 50 ° C., 1200 ° C. for steel B, 1100 ° C. for steels C, D and E, and the coil winding temperature was 800 ° C. for all.
【0022】[0022]
【表1】 [Table 1]
【0023】スケールおよび含Si酸化物層の厚さの測定
に関しては、熱延板より切り出し断面を研磨した試料の
研磨面をSEM観察し、その撮影像からスケール表面と
下地合金表面との距離を直接測定して得た値をスケール
厚さとし、さらにAES分析を行ってスケール層の組成
を同定し、Siピークが検出された層の厚さを測定して得
た値を含Si酸化物層厚さとした。また、このように同定
した含Si酸化物層をさらにX線回折で分析するとSiO2ピ
ークが認められた。Regarding the measurement of the thickness of the scale and the silicon-containing oxide layer, the polished surface of a sample cut out from a hot rolled plate and polished in cross section was observed by SEM, and the distance between the scale surface and the base alloy surface was determined from the photographed image. The value obtained by direct measurement is regarded as the scale thickness, and the composition of the scale layer is identified by AES analysis, and the value obtained by measuring the thickness of the layer where the Si peak is detected is used as the thickness of the Si oxide-containing layer. I did it. When the Si-containing oxide layer thus identified was further analyzed by X-ray diffraction, a SiO 2 peak was observed.
【0024】加工時のスケール密着性はスケール剥離量
で評価した。これは、熱延板の圧延方向に幅10mm×長さ
100mm の引張試験片を切り出し、該試験片の標点部分
(10mm×20mm)の表裏面に粘着テープを貼り付け、10%
の引張加工を施した後テープを剥がし取り、剥がし取っ
た前後でのテープの重量増分を測定して得たものであ
る。The scale adhesion at the time of processing was evaluated by the scale peeling amount. This is 10 mm width x length in the rolling direction of the hot rolled sheet.
Cut out a 100mm tensile test piece, apply adhesive tape to the front and back of the marked part (10mm x 20mm) of the test piece, and
The tape was peeled off after the tensile processing was performed, and the weight increase of the tape before and after peeling was measured.
【0025】酸洗性については、熱延板から 100×100m
m の試験片を切り出し、硫酸(H2SO4[200g/l]) と混酸(H
NO3[150g/l]+HF[25g/l])を用いて実験室的に酸洗を行
い、酸洗後の板面を目視観察して次の4段階のグレード
で評価した。 1:スケール残りなし (スケール残り部の面積率
0%) 2:点状スケール残りがある(スケール残り部の面積率
1%以下) 3:塊状スケール残りがある(スケール残り部の面積率
1%超え5%未満) 4:縞状スケール残りがある(スケール残り部の面積率
5%以上) これらの結果を表2に併せ示す。The pickling property is 100 × 100 m from the hot rolled sheet.
m test piece was cut out and mixed with sulfuric acid (H 2 SO 4 [200 g / l]) and mixed acid (H
Pickling was performed in a laboratory using NO 3 [150 g / l] + HF [25 g / l]), and the plate surface after the pickling was visually observed and evaluated according to the following four grades. 1: No remaining scale (0% area ratio of remaining scale) 2: There is a dot scale residue (1% or less area ratio of remaining scale) 3: There is a lump scale residue (1% area ratio of remaining scale) 4: Less than 5%) 4: Striped scale remains (area ratio of remaining scale is 5% or more). These results are also shown in Table 2.
【0026】[0026]
【表2】 [Table 2]
【0027】例えば、鋼Aのスラブ(SUS430[16C
r-0.06C];No.1〜15)を熱延した熱延板についての展伸
比と、スケール厚さ、含Si酸化物層厚さ、スケール剥離
量、酸洗性との関係を図1、図2、図3、図4にそれぞ
れ示す。スケール厚さおよび含Si酸化物層厚さは、スラ
ブ厚および熱延仕上げ厚のレベルに関わらず、展伸比が
高いものほど薄くなり、展伸比150 以上でスケール厚さ
2.5μm 以下が達成されると同時に含Si酸化物層厚さも
0.1μm 以下に制御できる。(図1、図2参照)。それ
に伴い、展伸比 150以上を満足するNo.5、10、11、1
2、15では、スケール剥離量が 0.1mg/cm2以下と非常に
少なく(図3参照)、また、酸洗後のスケール残りも見
られない(図4参照)。すなわち、この熱延板はスケー
ル除去を行わず黒皮(熱延タイトスケールの俗称)のま
まで加工しても金型劣化や粉塵公害などを起こす心配の
ないレベルのスケール密着性を備え、同時に酸洗前に機
械的スケール除去を行わなくても酸洗性に優れるスケー
ル構造が備わっている。For example, a slab of steel A (SUS430 [16C
r-0.06C]; No. 1 to 15), the relationship between the draw ratio of hot-rolled sheet, scale thickness, Si-containing oxide layer thickness, scale peeling amount, and pickling properties 1, 2, 3, and 4 respectively. Regardless of the slab thickness and the hot-rolled finish thickness, the scale thickness and the thickness of the Si-containing oxide layer become thinner as the elongation ratio becomes higher.
2.5μm or less is achieved and the thickness of the Si-containing oxide layer is
It can be controlled to 0.1μm or less. (See FIGS. 1 and 2). Along with that, No. satisfying an expansion ratio of 150 or more. 5, 10, 11, 1
In Nos. 2 and 15, the scale peeling amount was very small at 0.1 mg / cm 2 or less (see FIG. 3), and no scale residue after pickling was observed (see FIG. 4). In other words, this hot-rolled sheet has a level of scale adhesiveness that does not cause mold deterioration or dust pollution even if it is processed as black scale (common name of hot-rolled tight scale) without removing scale and at the same time, A scale structure with excellent pickling properties is provided without mechanical scale removal before pickling.
【0028】この傾向は、Niを多量に含有するオーステ
ナイトステンレス鋼スラブB(SUS304;No.16〜
20)およびCr量が11wt%程度と比較的少ないスラブC,
D(No.21〜26)でも同様である。しかし、Si含有量が
1.4wt%のスラブEを展伸比 200.0で製造した熱延板
(No.27)では、スケール厚さは 2.0μm に抑制されて
加工後のスケール剥離量は0.02mg/cm2と少なく良好なス
ケール密着性を示すものの、スケール層中の含Si酸化物
層の厚さが0.21μm と 0.1μm を超えており、酸洗後に
点状のスケール残りが見られた。This tendency is evident from the fact that austenitic stainless steel slab B containing a large amount of Ni (SUS304;
20) and slab C with relatively small Cr content of about 11 wt%,
The same applies to D (No. 21 to 26). However, the Si content
In the hot-rolled sheet (No. 27) produced with slab E of 1.4 wt% at an elongation ratio of 200.0, the scale thickness was suppressed to 2.0 μm, and the scale peeling amount after processing was as small as 0.02 mg / cm 2, which was excellent. Despite exhibiting scale adhesion, the thickness of the Si-containing oxide layer in the scale layer was 0.21 μm, which exceeded 0.1 μm, and dotted scale residues were observed after pickling.
【0029】以上、本発明方法に従って展伸比 150以上
で圧延された熱延ステンレス鋼板は、元のスラブ厚と熱
延仕上げ板厚によらず、黒皮のままで加工を施した場合
のスケール剥離量が少ないことが明らかである。また、
Si含有量を 1.0wt%以下に制限したステンレス鋼素材を
用いて本発明方法に従って熱延すれば、ショットブラス
ト等の機械的前処理を介さずとも酸洗脱スケール性に優
れた熱延ステンレス鋼板が得られることが明らかであ
る。As described above, the hot-rolled stainless steel sheet rolled at an elongation ratio of 150 or more in accordance with the method of the present invention has a scale obtained by processing with black scale regardless of the original slab thickness and the hot-rolled finished sheet thickness. It is clear that the amount of peeling is small. Also,
Hot-rolled stainless steel sheet excellent in pickling and descaling properties without mechanical pretreatment such as shot blasting, if hot-rolling is performed according to the method of the present invention using a stainless steel material having a Si content limited to 1.0 wt% or less. It is clear that is obtained.
【0030】[0030]
【発明の効果】本発明によれば、スケール密着性に秀で
た熱延ステンレス鋼板が得られるから、金型劣化や粉塵
公害の心配なくスケール付きのままの加工に供用でき、
さらに、ショットブラスト等の機械的スケール破壊処理
を施さなくともスケールを効率よく酸洗除去できること
から、冷間圧延工程を省略した熱延ままの製品要求仕様
に対してもショット目等の凹凸のない良好な表面性状の
ステンレス鋼板を提供することができる。According to the present invention, a hot-rolled stainless steel sheet excellent in scale adhesion can be obtained, so that it can be used for processing with a scale without fear of mold deterioration and dust pollution.
Furthermore, since the scale can be efficiently pickled and removed without performing mechanical scale destruction treatment such as shot blasting, there is no unevenness such as shots even for the hot rolled product required specification omitting the cold rolling step. A stainless steel plate having good surface properties can be provided.
【図面の簡単な説明】[Brief description of the drawings]
【図1】展伸比とスケール厚さとの関係を示すグラフで
ある。FIG. 1 is a graph showing a relationship between an expansion ratio and a scale thickness.
【図2】展伸比と含Si酸化物層厚さとの関係を示すグラ
フである。FIG. 2 is a graph showing the relationship between the elongation ratio and the thickness of a silicon-containing oxide layer.
【図3】展伸比と加工後のスケール剥離量との関係を示
すグラフである。FIG. 3 is a graph showing the relationship between the elongation ratio and the amount of scale peeling after processing.
【図4】展伸比と酸洗性との関係を示すグラフである。FIG. 4 is a graph showing a relationship between an elongation ratio and pickling properties.
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 平7−204703(JP,A) (58)調査した分野(Int.Cl.7,DB名) B21B 3/02,45/00 ────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-7-204703 (JP, A) (58) Fields investigated (Int. Cl. 7 , DB name) B21B 3 / 02,45 / 00
Claims (4)
厚さが 2.5μm 以下であることを特徴とする熱延ステン
レス鋼板。1. A hot-rolled stainless steel sheet containing 10 wt% or more of Cr and having a surface thickness of 2.5 μm or less.
もにスケール層と下地合金との界面に形成される含Si酸
化物層の厚さを 0.1μm 以下とする請求項1記載の熱延
ステンレス鋼板。2. The hot-rolled stainless steel according to claim 1, further comprising 1.0 wt% or less of Si and a thickness of a silicon-containing oxide layer formed at an interface between the scale layer and the base alloy being 0.1 μm or less. steel sheet.
延して鋼帯コイルとする熱延ステンレス鋼板の製造方法
において、下記に定義される展伸比が 150以上となるよ
うに熱間圧延することを特徴とする熱延ステンレス鋼板
の製造方法。 記 展伸比=(鋼帯コイルの圧延面の面積)/(スラブの圧
延面の面積)3. A method for producing a hot-rolled stainless steel sheet in which a slab containing Cr of 10% by weight or more is hot-rolled to form a steel strip coil, wherein a hot-rolled stainless steel sheet is formed so that an elongation ratio defined below becomes 150 or more. A method for producing a hot-rolled stainless steel sheet, characterized by rolling. Elongation ratio = (Area of rolled surface of steel strip coil) / (Area of slab rolled surface)
有する請求項3記載の方法。4. The method according to claim 3, wherein said slab further contains 1.0 wt% or less of Si.
Priority Applications (6)
Application Number | Priority Date | Filing Date | Title |
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JP08259318A JP3091418B2 (en) | 1996-09-30 | 1996-09-30 | Hot rolled stainless steel sheet and method for producing the same |
TW086114158A TW338729B (en) | 1996-09-30 | 1997-09-27 | Hot roll stainless steel tape and the manufacturing method |
US08/939,945 US5948181A (en) | 1996-09-30 | 1997-09-29 | Hot-rolled stainless steel strip and method for producing the same |
KR1019970049636A KR100237526B1 (en) | 1996-09-30 | 1997-09-29 | Hot-rolled stainless steel strip and method for producing the same |
DE69717757T DE69717757T2 (en) | 1996-09-30 | 1997-09-30 | Hot rolled stainless steel strip and process for its manufacture |
EP97307720A EP0835698B1 (en) | 1996-09-30 | 1997-09-30 | Hot-rolled stainless steel strip and method for producing the same |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP08259318A JP3091418B2 (en) | 1996-09-30 | 1996-09-30 | Hot rolled stainless steel sheet and method for producing the same |
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JPH1099912A JPH1099912A (en) | 1998-04-21 |
JP3091418B2 true JP3091418B2 (en) | 2000-09-25 |
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ID=17332421
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CN102921726B (en) * | 2012-11-15 | 2015-04-22 | 沈阳大学 | Method for improving corrosion resistance of hot-rolled plate by utilizing oxide scale |
JP6376218B2 (en) * | 2014-09-10 | 2018-08-22 | 新日鐵住金株式会社 | Austenitic stainless steel sheet that is difficult to diffuse and bond |
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