JP3868069B2 - Stainless steel descaling apparatus and descaling method - Google Patents
Stainless steel descaling apparatus and descaling method Download PDFInfo
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- pickling
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Description
【０００１】
【発明の属する技術分野】
本発明は、熱間加工の際に、あるいは熱処理の際にステンレス鋼の表面にできたスケールを除去するための、ステンレス鋼のデスケール装置及びデスケール方法に関する。
【０００２】
【従来の技術】
ステンレス鋼のスケールを除去するためには、通常は硝酸−弗酸の酸洗液を用いている。しかし近年、廃棄された硝酸あるいは硝酸塩は環境汚染を起こすために規制が強化される趨勢にある。このため硝酸を用いないステンレス鋼の酸洗法が望まれている。表面にスケールが発生したステンレス鋼を、溶融アルカリのソルトバスに浸漬するとスケールが変質し、その後の酸洗でスケールの除去が容易となる事が知られている。しかしこのソルトバスを用いるデスケール方法においても、ソルトバス後の酸洗には従来は専ら硝酸−弗酸の酸洗液が用いられていた。このため硝酸の使用量を十分には低減する事ができなかった。
【０００３】
【発明が解決しようとする課題】
本発明は、硝酸、硝酸塩の廃棄量を十分に低減する事ができ、かつ従来よりも高能率でスケールを除去する事が可能な、ステンレス鋼のデスケール装置とデスケール方法の提供を課題としている。
【０００４】
【課題を解決するための手段】
本発明は、（１）入側から出側方向に、１または２以上の酸洗槽を有する予備系列と、溶融アルカリを収納したソルトバスと、１または２以上の酸洗槽を有する仕上系列とを順次配してなるステンレス鋼のデスケール装置において、何れの酸洗槽にも硝酸を含有する酸洗液を用いる事なく、また予備系列と仕上系列のそれぞれの少なくとも１の酸洗槽を硫酸−弗酸の酸洗槽とし、仕上系列の硫酸−弗酸の酸洗槽の使用済みの液を予備系列の硫酸−弗酸の酸洗槽に供給する構造とした事を特徴とする、ステンレス鋼のデスケール装置である。
【０００５】
また（２）予備系列の硫酸−弗酸の酸洗槽が、硫酸：２５〜６０ｇ／Ｌ，ＨＦ：３〜１０ｇ／Ｌの硫酸−弗酸の酸洗槽であり、仕上系列の硫酸−弗酸の酸洗槽が、硫酸４０〜８０ｇ／Ｌ，ＨＦ：５〜１５ｇ／Ｌ，Ｆｅ3+＞５ｇ／Ｌの硫酸−弗酸の酸洗槽である事を特徴とする、前記（１）に記載のフェライト系ステンレス鋼のデスケール装置である。
【０００６】
また（３）予備系列の硫酸−弗酸の酸洗槽が、硫酸：６０〜２００ｇ／Ｌ，ＨＦ：１０〜２５ｇ／Ｌの硫酸−弗酸の酸洗槽であり、仕上系列の硫酸−弗酸の酸洗槽がＨ2ＳＯ4：１００〜２５０ｇ／Ｌ，ＨＦ：１５〜５０ｇ／Ｌ，Ｆ3+＞５ｇ／Ｌの硫酸−弗酸の酸洗槽である事を特徴とする、前記（１）に記載のオーステナイト系ステンレス鋼のデスケール装置である。
【０００７】
また（４）硫酸−弗酸の酸洗液が、温度が３５〜６５℃の硫酸−弗酸の酸洗液であることを特徴とする、前記（１）〜（３）の何れかに記載のステンレス鋼のデスケール装置である。
【０００８】
尚、前記（１）〜（４）において仕上系列の硫酸−弗酸の酸洗槽を、浴の酸化還元電位を＋２５０ｍＶ以上に維持し浴中のＦｅ２＋を一定割合でＦｅ３＋に変換するための過酸化水素を添加する仕上系列の硫酸−弗酸の酸洗槽としてもよい。
【０００９】
また（５）予備系列の硫酸−弗酸の酸洗槽と、仕上系列の硫酸−弗酸の酸洗槽の一方あるいは双方が、２０〜３０Ｎｍ３／ｈｒ／ｍ３当たりの空気を連続的に導入する硫酸−弗酸の酸洗槽であることを特徴とする、前記（１）から（４）の何れかに記載のオーステナイト系ステンレス鋼のデスケール装置である。
【００１０】
また（６）前記（２），（４），（５）何れかに記載のデスケール装置によりデスケーリングを行う事を特徴とする、フェライト系ステンレス鋼のデスケール方法である。
【００１１】
また（７）前記（３），（４），（５）の何れかに記載のデスケール装置によりデスケーリングを行う事を特徴とする、オーステナイト系ステンレス鋼のデスケール方法である。
【００１２】
本発明では酸洗液が硝酸を含有しないものであれば、予備系列、仕上系列に更に他の酸洗槽を配する事を拒むものではない。本発明の各酸洗槽の間には、あるいは酸洗槽とソルトバスの間には、必要に応じて酸洗液等が混じりあう事を防止するための公知の水洗設備が設けられており、また最後の酸洗槽の後には公知の水洗設備やデスマット機能を備えた水洗設備が設けられている事は云うまでもない。
【００１３】
【発明の実施の形態】
予備系列では、従来は硫酸、塩酸等が酸洗液として使用されている。本発明ではこれ等に代えて、硫酸−弗酸の酸洗液を用いる。本発明では仕上系列で使用済みの酸洗液を用いるが、この硫酸−弗酸の酸洗液は従来の硫酸あるいは塩酸に比べてステンレス鋼のスケールに強く作用し、次ぎのソルトバスに入る際のステンレス鋼のスケールを従来よりも著しく薄くする。この結果、ソルトバスを出た後のステンレス鋼のスケールは、従来よりも一層除去が容易となる。
【００１４】
予備系列の酸洗液は、フェライト系ステンレス鋼の場合は、硫酸：２５〜６０ｇ／Ｌ，ＨＦ：３〜１０ｇ／Ｌのものが好ましい。またオーステナイト系ステンレス鋼の場合は、硫酸６０〜２００ｇ／Ｌ，ＨＦ：１０〜２５ｇ／Ｌのものが好ましい。本発明では予備系列の酸洗液を後で述べる仕上系列の酸洗液と同じ種類の硫酸−弗酸系とし、仕上系列で使用済みの硫酸−弗酸の酸洗液を仕上系列の硫酸−弗酸の酸洗槽から受け入れて使用する。この結果、仕上系列の硫酸−弗酸の酸洗液は予備系列で再利用され、また予備系列では従来の酸洗液よりも強い作用を有する酸洗液となって再利用される。
【００１５】
ソルトバスを用いない場合はステンレス鋼のデスケールには長時間を要する。本発明では、スケールを高能率に除去するために、溶融アルカリのソルトバスを用いる。ステンレス鋼のスケールはこの溶融アルカリによって変質し除去が容易となる。このソルトバス用のソルトとしては、例えばコリーンソルトＤＧＳ（商品名、(株)パーカーコーポレーション製）を４３０〜４７０℃に加熱して使用する事ができる。
【００１６】
仕上系列では、従来は硝酸−弗酸が酸洗液として使用されている。本発明では硝酸を用いないで、硫酸−弗酸の酸洗液を用いる。本発明の仕上系列の酸洗液は硫酸−弗酸であるが、予備系列でスケールが十分に薄くなっているために、またソルトバスでこの薄いスケールも除去し易いように変質しているために、従来の硝酸−弗酸の場合と同様に、あるいは従来の硝酸−弗酸の場合よりも高能率でスケールを除去することができる。
【００１７】
仕上系列の酸洗液は、フェライト系ステンレス鋼の場合は、硫酸４０〜８０ｇ／Ｌ，ＨＦ：５〜１５ｇ／Ｌ，Ｆｅ3+＞５ｇ／Ｌのものが好ましい。またオーステナイト系ステンレス鋼の場合は、Ｈ2ＳＯ4：１００〜２５０ｇ／Ｌ，ＨＦ：１５〜５０ｇ／Ｌ，Ｆｅ3+＞５ｇ／Ｌのものが好ましい。Ｆｅ3+は、例えば硫酸第２鉄として酸洗液に添加する。Ｆｅ3+は、２Ｆｅ3+＋Ｆｅ→３Ｆｅ2+となるために、酸化剤として硝酸にとって代われる。
【００１８】
操業中のＦｅ3+は、溶液中のＦｅ2+を一定割合で変換して得られる事が好ましい。酸洗液中の酸化還元電位が＋２５０ｍＶ以上で酸洗液中のＦｅ3+はステンレス鋼表面でＦｅ2+に定常的に一定速度で変化する。この酸化還元電位は、酸洗液に過酸化水素を添加する事により、また２０〜３０Ｎｍ3／ｈｒ／酸洗液１ｍ3の空気を酸洗液に連続的に導入する事により、あるいは双方を行う事により＋２５０ｍＶ以上とする事ができる。
【００１９】
仕上系列の酸洗液は、周期的に分析する事によりその成分を管理するが、酸洗力が劣化した場合は、既に述べた如く予備系列の酸洗槽に移送し、仕上系列の酸洗液には硫酸、弗酸等を添加補充して酸洗力を回復させて使用する。
【００２０】
【実施例】
本発明者等は、フェライト系ステンレス鋼（JIS SUS430ステンレス鋼）の熱延線材を焼鈍後、予備系列、仕上系列の酸を変えて、デスケーリングを行った。その結果を表１に示した。番号１〜４は予備系列に塩酸又は硫酸を用い、仕上系列に硝酸−弗酸を用いた従来例である。この際には各処理時間が１０分で、ライン速度が遅い場合には優れた脱スケール結果が得られるが、処理時間が５分の高能率デスケールの場合は脱スケール結果は悪い。番号５は予備系列にも硝酸−弗酸を用いた例であるが、この際には処理時間が５分の場合にも優れたデスケール結果が得られるる。しかしこの際には、硝酸の使用量が多くなるという問題点が発生する。
【００２１】
番号６は、予備系列に本発明の予備系列用の酸洗液よりも希薄な硫酸−弗酸の酸洗液を用いた比較例であり、番号７は仕上系列に本発明よりも希薄な酸洗液を用いた比較例である。これ等の場合に、処理時間が５分の高能率デスケールを行うと、脱スケールは不十分となる。
【００２２】
【表１】
番号８及び９は予備系列および仕上系列の双方に本発明でそれぞれ特定した硫酸−弗酸の酸洗液を用いた例である。この際には処理時間が１０分の場合も、また処理時間が５分の高能率デスケールの場合も、極めて優れた脱スケール結果が得られた。
【００２４】
本発明者等は、オーステナイト系ステンレス鋼（JIS SUS304ステンレス鋼）の熱延線材を焼鈍後、鋼帶を、予備系列、仕上系列の酸を変えて、デスケーリングを行った。その結果を表２に示した。番号１１〜１４は予備系列に塩酸又は硫酸を用い、仕上系列に硝酸−弗酸を用いた従来例である。この際には各処理時間が１０分でライン速度が遅い場合には優れた脱スケール結果が得られるが、処理時間が５分の高能率デスケールの場合には脱スケール結果は不十分でありあるいは不良である。
【００２５】
【表２】
番号５は予備系列にも硝酸−弗酸を用いた例である。この際の予備系列の液は仕上系列で使用したものではないが、脱スケール性は不十分である。番号１６は予備系列に本発明よりも希薄な硫酸−弗酸の酸洗液を用いた比較例であり、番号１７は仕上系列に本発明よりも希薄な酸洗液を用いた比較例である。これ等の場合に、処理時間が５分の高能率デスケーリングを行うと、脱スケールは不十分となる。
【００２７】
番号１８及び１９は予備系列および仕上系列の双方に本発明でそれぞれ特定した硫酸−弗酸の酸洗液を用いた例である。この際には処理時間が１０分の、ライン速度が遅い場合も、また処理時間が５分の高能率デスケールの場合も、極めて優れた脱スケール結果が得られた。
【００２８】
【発明の効果】
本発明によると、硝酸を用いないで、且つ従来よりも高能率で、ステンレス鋼のスケールを除去する事ができる。本発明を線材のデスケーリングの実施例について述べたが、本発明はステンレス鋼板、ステンレス鋼パイプ、ステンレス棒鋼などの形状の異なるステンレス鋼のデスケーリングにも適用できることはいうまでもない。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a stainless steel descaling apparatus and a descaling method for removing scale formed on the surface of stainless steel during hot working or heat treatment.
[0002]
[Prior art]
In order to remove the stainless steel scale, a pickling solution of nitric acid-hydrofluoric acid is usually used. In recent years, however, discarded nitric acid or nitrates have been in a tendency to be tightened in order to cause environmental pollution. For this reason, the pickling method of the stainless steel which does not use nitric acid is desired. It is known that when stainless steel with a scale formed on it is immersed in a molten alkali salt bath, the scale is altered, and the scale can be easily removed by subsequent pickling. However, even in the descaling method using the salt bath, nitric acid-hydrofluoric acid pickling solution has been conventionally used for the pickling after the salt bath. For this reason, the amount of nitric acid used could not be reduced sufficiently.
[0003]
[Problems to be solved by the invention]
An object of the present invention is to provide a stainless steel descaling apparatus and a descaling method that can sufficiently reduce the amount of nitric acid and nitrate discarded, and that can remove scales more efficiently than before.
[0004]
[Means for Solving the Problems]
The present invention includes (1) a preliminary series having one or two or more pickling tanks, a salt bath containing molten alkali, and a finishing series having one or two or more pickling tanks from the inlet side to the outlet side. In the stainless steel descaler, which is arranged sequentially, at least one pickling tank in each of the preliminary series and the finishing series is not used in any pickling tank without using a pickling solution containing nitric acid. Stainless steel characterized in that it has a structure in which used liquid of a finishing-type sulfuric acid-hydrofluoric acid pickling tank is supplied to a preliminary series of sulfuric acid-hydrofluoric acid pickling tank as a hydrofluoric acid pickling tank It is a steel descaling device.
[0005]
(2) The sulfuric acid-hydrofluoric acid pickling tank of the preliminary series is a sulfuric acid-hydrofluoric acid pickling tank of sulfuric acid: 25-60 g / L and HF: 3-10 g / L. The acid pickling tank is a sulfuric acid-hydrofluoric acid pickling tank of sulfuric acid 40-80 g / L, HF: 5-15 g / L, Fe 3+ > 5 g / L, (1) 2. A descaling device for ferritic stainless steel described in 1.
[0006]
(3) The sulfuric acid-hydrofluoric acid pickling tank of the preliminary series is a sulfuric acid-hydrofluoric acid pickling tank of sulfuric acid: 60 to 200 g / L, HF: 10 to 25 g / L, and the finishing series sulfuric acid-hydrofluoric acid tank. The acid pickling tank is a sulfuric acid-hydrofluoric acid pickling tank of H 2 SO 4 : 100 to 250 g / L, HF: 15 to 50 g / L, F 3+ > 5 g / L, It is a descaling apparatus of the austenitic stainless steel as described in (1).
[0007]
(4) The sulfuric acid-hydrofluoric acid pickling solution is a sulfuric acid-hydrofluoric acid pickling solution having a temperature of 35 to 65 ° C. Stainless steel descaling equipment.
[0008]
Incidentally, the above (1) to (4) sulfate above sequence specification in - converting the pickling bath hydrofluoric acid, the Fe 2+ of maintaining bath redox potential + 250mV above the bath to Fe 3+ at a constant rate It is also possible to use a finishing-type sulfuric acid-hydrofluoric acid pickling tank in which hydrogen peroxide is added .
[0009]
Further, (5) one or both of a preliminary series sulfuric acid-hydrofluoric acid pickling tank and a finishing series sulfuric acid-hydrofluoric acid pickling tank continuously supply air per 20-30 Nm 3 / hr / m 3. The descaling apparatus for austenitic stainless steel according to any one of (1) to (4) , wherein the apparatus is a sulfuric acid-hydrofluoric acid pickling tank to be introduced.
[0010]
The (6) above (2), (4), (5), characterized in that performing the descaling by descaling device according to what Re or a descaling method of ferritic stainless steel.
[0011]
(7) A descaling method for austenitic stainless steel, wherein the descaling is performed by the descaling apparatus according to any one of (3), (4), and (5 ) .
[0012]
In the present invention, if the pickling solution does not contain nitric acid, it does not refuse to arrange another pickling tank in the preliminary series and the finishing series. Between each pickling tank of the present invention, or between the pickling tank and the salt bath, there is provided a known water washing facility for preventing the pickling liquid and the like from being mixed if necessary. Needless to say, after the last pickling tank, a well-known water washing facility or a water washing facility having a desmut function is provided.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
In the preliminary series, conventionally, sulfuric acid, hydrochloric acid, and the like are used as the pickling solution. In the present invention, a pickling solution of sulfuric acid-hydrofluoric acid is used instead. In the present invention, a used pickling solution is used in the finishing series. This sulfuric acid-hydrofluoric acid pickling solution acts more strongly on the stainless steel scale than conventional sulfuric acid or hydrochloric acid, and enters the next salt bath. The stainless steel scale is significantly thinner than before. As a result, the stainless steel scale after leaving the salt bath is easier to remove than in the prior art.
[0014]
In the case of a ferritic stainless steel, the preliminary pickling solution is preferably sulfuric acid: 25-60 g / L, HF: 3-10 g / L. In the case of austenitic stainless steel, sulfuric acid of 60 to 200 g / L, HF: 10 to 25 g / L is preferable. In the present invention, the preliminary pickling solution is the same type of sulfuric acid-hydrofluoric acid type as the finishing series pickling solution described later, and the sulfuric acid-hydrofluoric acid pickling solution used in the finishing series is the finishing type sulfuric acid- Used from a pickling tank of hydrofluoric acid. As a result, the finishing series sulfuric acid-hydrofluoric acid pickling liquid is reused in the preliminary series, and in the preliminary series, it is reused as a pickling liquid having a stronger action than the conventional pickling liquid.
[0015]
When a salt bath is not used, it takes a long time to descale stainless steel. In the present invention, a molten alkali salt bath is used in order to efficiently remove the scale. The stainless steel scale is altered by the molten alkali and can be easily removed. As the salt for the salt bath, for example, Colleen Salt DGS (trade name, manufactured by Parker Corporation) can be heated to 430 to 470 ° C. and used.
[0016]
In the finishing series, nitric acid-hydrofluoric acid is conventionally used as the pickling solution. In the present invention, sulfuric acid-hydrofluoric acid pickling solution is used without using nitric acid. The finishing series pickling solution of the present invention is sulfuric acid-hydrofluoric acid, but the scale is sufficiently thin in the preliminary series, and the thin scale is easily altered by a salt bath so that it can be easily removed. In addition, the scale can be removed in the same manner as in the case of conventional nitric acid-hydrofluoric acid or at a higher efficiency than in the case of conventional nitric acid-hydrofluoric acid.
[0017]
In the case of ferritic stainless steel, the finishing series pickling solution is preferably 40 to 80 g / L sulfuric acid, HF: 5 to 15 g / L, and Fe 3+ > 5 g / L. In the case of austenitic stainless steel, H 2 SO 4 : 100 to 250 g / L, HF: 15 to 50 g / L, and Fe 3+ > 5 g / L are preferable. For example, Fe 3+ is added to the pickling solution as ferric sulfate. Since Fe 3+ becomes 2Fe 3+ + Fe → 3Fe 2+ , it is replaced by nitric acid as an oxidizing agent.
[0018]
Fe 3+ in the operation, it is preferably obtained by converting the Fe 2+ in the solution at a constant rate. When the oxidation-reduction potential in the pickling solution is +250 mV or more, Fe 3+ in the pickling solution changes constantly to Fe 2+ at a constant rate on the stainless steel surface. This oxidation-reduction potential can be achieved by adding hydrogen peroxide to the pickling solution, continuously introducing 20-30 Nm 3 / hr / 1 m 3 pickling solution into the pickling solution, or both. By doing so, it can be +250 mV or more.
[0019]
The components of the finishing series pickling solution are controlled by periodic analysis. However, if the pickling ability deteriorates, it is transferred to the preliminary series pickling tank as described above, and the finishing series pickling solution is used. The solution is replenished with sulfuric acid, hydrofluoric acid, etc. to recover the pickling power.
[0020]
【Example】
The inventors of the present invention performed descaling by annealing the hot-rolled wire of ferritic stainless steel (JIS SUS430 stainless steel), changing the acid in the preliminary series and finishing series. The results are shown in Table 1. Nos. 1 to 4 are conventional examples using hydrochloric acid or sulfuric acid for the preliminary series and nitric acid-hydrofluoric acid for the finishing series. At this time, each processing time is 10 minutes, and an excellent descaling result can be obtained when the line speed is low, but the descaling result is poor when the processing time is a high efficiency descale. No. 5 is an example in which nitric acid-hydrofluoric acid is also used for the preliminary series. In this case, an excellent descale result can be obtained even when the treatment time is 5 minutes. However, in this case, there arises a problem that the amount of nitric acid used is increased.
[0021]
No. 6 is a comparative example using a sulfuric acid-hydrofluoric acid pickling solution diluted in a preliminary series as compared with the preliminary series pickling solution of the present invention, and No. 7 is a diluted acid in the finishing series than in the present invention. It is a comparative example using a washing | cleaning liquid. In these cases, if high-efficiency descaling is performed for 5 minutes, descaling becomes insufficient.
[0022]
[Table 1]
Nos. 8 and 9 are examples using the sulfuric acid-hydrofluoric acid pickling solution specified in the present invention for both the preliminary series and the finishing series. In this case, an extremely excellent descaling result was obtained both in the case where the treatment time was 10 minutes and in the case of the high-efficiency descaling where the treatment time was 5 minutes.
[0024]
The inventors of the present invention performed descaling by annealing austenitic stainless steel (JIS SUS304 stainless steel) hot-rolled wire rods, changing the steel rods in the preliminary series and finishing series. The results are shown in Table 2. Numbers 11 to 14 are conventional examples using hydrochloric acid or sulfuric acid for the preliminary series and nitric acid-hydrofluoric acid for the finishing series. In this case, an excellent descaling result is obtained when each processing time is 10 minutes and the line speed is slow, but when the processing time is a high efficiency descale, the descaling result is insufficient or It is bad.
[0025]
[Table 2]
No. 5 is an example in which nitric acid-hydrofluoric acid is also used for the preliminary series. The preliminary series liquid at this time is not used in the finishing series, but the descalability is insufficient. Reference numeral 16 is a comparative example using a dilute sulfuric acid-hydrofluoric acid pickling solution for the preliminary series, and No. 17 is a comparative example using a dilute pickling liquid for the finishing series. . In these cases, descaling becomes insufficient when high-efficiency descaling is performed for 5 minutes.
[0027]
Nos. 18 and 19 are examples using the sulfuric acid-hydrofluoric acid pickling solution specified in the present invention for both the preliminary series and the finishing series. In this case, an extremely excellent descaling result was obtained both when the processing time was 10 minutes and the line speed was low, and when the processing time was high-efficiency descaling.
[0028]
【The invention's effect】
According to the present invention, the scale of stainless steel can be removed without using nitric acid and with higher efficiency than in the past. Although the present invention has been described with respect to the embodiment of the descaling of the wire, it goes without saying that the present invention can also be applied to descaling of stainless steels having different shapes such as stainless steel plates, stainless steel pipes, stainless steel bars and the like.
Claims (7)
Ｈ２ＳＯ４：１００〜２５０ｇ／Ｌ，ＨＦ：１５〜５０ｇ／Ｌ，Ｆｅ３＋＞５ｇ／Ｌの硫酸−弗酸の酸洗槽である事を特徴とする、請求項１に記載のオーステナイト系ステンレス鋼のデスケール装置。The preliminary sulfuric acid-hydrofluoric acid pickling tank is a sulfuric acid-hydrofluoric acid pickling tank of sulfuric acid: 60 to 200 g / L, HF: 10-25 g / L, and the finishing sulfuric acid-hydrofluoric acid pickling tank. vat H 2 SO 4: 100~250g / L , HF: 15~50g / L, sulfuric acid Fe 3+> 5g / L - characterized in that it is a pickling bath hydrofluoric acid, according to claim 1 Descaler for austenitic stainless steel.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20562897A JP3868069B2 (en) | 1997-07-31 | 1997-07-31 | Stainless steel descaling apparatus and descaling method |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20562897A JP3868069B2 (en) | 1997-07-31 | 1997-07-31 | Stainless steel descaling apparatus and descaling method |
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| Publication Number | Publication Date |
|---|---|
| JPH1150283A JPH1150283A (en) | 1999-02-23 |
| JP3868069B2 true JP3868069B2 (en) | 2007-01-17 |
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| KR101289147B1 (en) * | 2010-12-28 | 2013-07-23 | 주식회사 포스코 | Environmental-Friendly and High Speed Pickling Process for Ferritic Stainless Cold Strip with Good Surface Quality |
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