JPH0841666A - Descaling picking method - Google Patents

Descaling picking method

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Publication number
JPH0841666A
JPH0841666A JP17675094A JP17675094A JPH0841666A JP H0841666 A JPH0841666 A JP H0841666A JP 17675094 A JP17675094 A JP 17675094A JP 17675094 A JP17675094 A JP 17675094A JP H0841666 A JPH0841666 A JP H0841666A
Authority
JP
Japan
Prior art keywords
acid
steel
sulfuric acid
descaling
pickling
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.)
Pending
Application number
JP17675094A
Other languages
Japanese (ja)
Inventor
Yoshihiro Kuroki
義博 黒木
Mitsuaki Uchida
満秋 内田
Yoji Toki
洋司 土岐
Masatoshi Nakagawa
誠敏 中川
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Daido Steel Co Ltd
Original Assignee
Daido Steel Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Daido Steel Co Ltd filed Critical Daido Steel Co Ltd
Priority to JP17675094A priority Critical patent/JPH0841666A/en
Publication of JPH0841666A publication Critical patent/JPH0841666A/en
Pending legal-status Critical Current

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  • Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)

Abstract

PURPOSE:To prevent the pitting of the surface of a steel at the time of removing the scale on the steel surface by pickling by conducting pickling in two stages respectively in a bath with the composition regulated. CONSTITUTION:When the scale formed on the surface of a steel is removed, the steel is dipped in about 10% aq. sulfuric acid to dissolve and remove the scale consisting of Fe3O4, Fe2O3, FeO, etc. The steel surface is then washed with water, the remaining aq. sulfuric acid is neutralized with aq. NaOH, and the steel is introduced into a surface-treating tank contg. aq. KMnO4 alkalized with NaOH to make the scale which has not been dissolved in the aq. sulfuric acid easily soluble in acid. The steel is then secondly pickled after shower washing with aq. sulfuric acid to completely dissolve off the scale on the steel surface. In this operation, when the first and second aq. sulfuric acid are electrolyzed to recover sulfuric acid, the first and second aq. sulfuric acid are separately electrolyzed, hence the Mn ion content of the first aq. sulfuric acid is reduced to >=500ppm, and the steel surface is not pitted.

Description

【発明の詳細な説明】Detailed Description of the Invention

【0001】[0001]

【産業上の利用分野】本発明は鋼材を脱スケールの目的
で酸洗処理する方法の改良に関し、ピッチング(孔食)
の発生を防止した酸洗方法を提供する。
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a method of pickling a steel material for the purpose of descaling, such as pitting.
A pickling method that prevents the occurrence of

【0002】[0002]

【従来の技術】鋼材とくに線材のコイルを脱スケールの
ため酸洗処理する酸浴として、以前は塩酸浴が多く用い
られたが、塩酸ヒュームが装置の腐食をひきおこすとと
もに環境に悪影響を与えるので、現在はほとんど硫酸浴
で酸洗が実施されている。 ところが硫酸浴には、脱ス
ケールに伴ってピッチングが生じるという欠点がある。
2. Description of the Related Art Hydrochloric acid baths have been widely used as acid baths for pickling steel coils, especially wire coils, for descaling, but since fume hydrochloric acid causes corrosion of equipment and adversely affects the environment, Currently, most pickling is carried out in a sulfuric acid bath. However, the sulfuric acid bath has a drawback that pitting occurs along with descaling.

【0003】一方、酸洗後の酸液をイオン交換膜をそな
えた浴で電解して酸を分離回収し、再利用することが行
なわれている。 この酸回収再利用を行なうとき、ピッ
チングの問題はいっそう深刻になる。
On the other hand, the acid solution after pickling is electrolyzed in a bath provided with an ion exchange membrane to separate and recover the acid and reuse it. When performing this acid recovery and reuse, the problem of pitching becomes more serious.

【0004】[0004]

【発明が解決しようとする課題】本発明の目的は、鋼材
の脱スケール酸洗に伴う上記の問題を解消し、ピッチン
グの発生を回避して脱スケールを行なうことのできる酸
洗方法を提供することにある。
SUMMARY OF THE INVENTION An object of the present invention is to provide a pickling method which solves the above problems associated with the descaling and pickling of steel materials and which can perform descaling while avoiding the occurrence of pitting. Especially.

【0005】[0005]

【課題を解決するための手段】本発明の鋼材の脱スケー
ル酸洗方法は、鋼材を硫酸浴で脱スケールする酸洗方法
であって、酸浴浸漬I−中和−表面調整−酸浴浸漬II−
被膜処理の諸工程からなる方法において、酸浴浸漬Iの
酸浴として、その中のMnイオンの合計量を500ppm
以下に規制したものを使用することを特徴とする。
The descaling and pickling method for steel products according to the present invention is a pickling method for descaling steel products in a sulfuric acid bath, which is acid bath dipping I-neutralization-surface conditioning-acid bath dipping. II-
In a method consisting of various steps of coating treatment, the total amount of Mn ions in the acid bath Immersion I is 500 ppm.
It is characterized by using those regulated below.

【0006】使用後の酸液を電解処理して酸を分離回収
し循環再使用する場合は、酸浴浸漬Iの酸液と酸浴浸漬
IIの酸液とを混合することなく別個に処理し別個に循環
させるべきである。
When the acid solution after use is electrolytically treated to separate and collect the acid for reuse by circulation, the acid solution of the acid bath dipping I and the acid bath dipping
It should be treated separately and circulated separately without mixing with the acid solution of II.

【0007】[0007]

【作用】脱スケールのための酸洗は、通常、まず10%
程度のH2SO4温浴槽に鋼材を浸漬し(酸浴浸漬I)、
表面の酸化物(Fe34,Fe23,FeO)を溶解す
ることからはじまる。 シャワーで水洗してから中和槽
で酸を中和し、鋼材はデスマット調整槽とよばれる表面
調整槽に送られる。(「デスマット」とは、酸難溶性の
スケール「スマット」を酸易溶性のスケールに改質する
操作である。)ここでは、H2SO4浴で溶解されなかっ
た鋼材表面のFe−Cr−O化合物を、アルカリ性のK
MnO4水溶液中で酸に溶けやすい形態に変える。
Function: Pickling for descaling is usually 10%
Immerse the steel material in a hot H 2 SO 4 bath (acid bath immersion I),
It begins with the dissolution of surface oxides (Fe 3 O 4 , Fe 2 O 3 , FeO). After washing with water in a shower and neutralizing the acid in a neutralizing tank, the steel material is sent to a surface conditioning tank called a desmut adjusting tank. (By "desmutting" is an operation to modify the scale "smut" acid sparingly soluble scale of San'eki soluble.) In this case, Fe-Cr- of undissolved steel surface in H 2 SO 4 bath O compound, alkaline K
Change to a form that is easily soluble in acid in MnO 4 aqueous solution.

【0008】表面調整を受けた鋼材は、シャワー水洗を
経て、第二のH2SO4温浴槽に入り(酸浴浸漬II)、前
の工程で溶けやすくされたFe−Cr−O化が溶解す
る。このようにして酸洗を終った鋼材は、シャワー水洗
ののち、発錆を防止し後続の伸線作業を容易にするため
の被膜処理を受けて、製品となる。
The steel material subjected to the surface conditioning is washed with shower water and then enters a second hot bath of H 2 SO 4 (acid bath dipping II) to dissolve the Fe-Cr-O compound, which was easily dissolved in the previous step. To do. The steel material that has been pickled in this way is subjected to a coating treatment for preventing rusting and facilitating the subsequent wire drawing work after shower rinsing and becomes a product.

【0009】上記のプロセスにおいてピッチングの原因
を追求したところ、Fe3+の存在がFe3++Fe→2F
2+の機構により、鋼材の地金を溶かし出す現象として
ピッチングが起ることがわかった。
[0009] was pursuing the cause of pitching in the above-mentioned process, the presence of Fe 3+ is Fe 3+ + Fe → 2F
It has been found that the mechanism of e 2+ causes pitting as a phenomenon of melting the metal of the steel material.

【0010】Fe3+イオンは、H2SO4にFeが溶解し
ただけでは発生せず、Fe2+が酸化を受けることにより
生成する。 Fe2+を酸化してFe3+にする酸化力のあ
るイオンは、Mn7+,Mn4+およびCr6+である。 鋼
材がH2SO4に溶けたとき、Mn6+やCr3+が生成する
が、これらは安定で酸化力に乏しいことから、Fe2+
Fe3+に酸化するのは、主として調整槽のMnO4 -に由
来するMn7+と考えられる。 Mn7+は酸性では安定で
あるがアルカリ性では不安定で、他のものを酸化して安
定なMn6+になろうとする。 調整槽で鋼材に付着した
MnO4 -をシャワーにより完全に取除くことは困難であ
って、MnO4 -は酸浴浸漬IIのH2SO4浴に入り、酸液
の電解回収に際してSO4 2-アニオンに伴われて再生硫
酸の中に入り、酸浴浸漬Iの酸液中に混入して行く。
このMnO4 -に含まれるMn7+が、中和槽におけるアル
カリ性条件下でピッチングをひきおこすと理解される。
Fe 3+ ions are not generated only by dissolving Fe in H 2 SO 4 , but are generated by oxidation of Fe 2+ . The oxidizing ions of Fe 2+ to Fe 3+ are Mn 7+ , Mn 4+ and Cr 6+ . When steel materials are dissolved in H 2 SO 4 , Mn 6+ and Cr 3+ are generated, but since these are stable and have poor oxidizing power, it is mainly the adjustment tank that oxidizes Fe 2+ to Fe 3+. It is considered to be Mn 7+ derived from MnO 4 . Mn 7+ is stable in acid but unstable in alkaline, and tends to oxidize other substances to become stable Mn 6+ . It is difficult to completely remove MnO 4 adhered to the steel material by a shower in the adjusting tank, and MnO 4 enters the H 2 SO 4 bath of the acid bath immersion II, and SO 4 2 is used for electrolytic recovery of the acid solution. - is accompanied anions enters the reproduction sulfate, go mixed acid solution of acid bath immersion I.
It is understood that Mn 7+ contained in this MnO 4 causes pitting under alkaline conditions in the neutralization tank.

【0011】従って、酸浴浸漬Iの工程にMn7+(存在
するとすればMn4+も)を存在させないことが、ピッチ
ングの防止に有効という結論になる。
Therefore, it is concluded that the absence of Mn 7+ (and Mn 4+ , if present) in the step of acid bath dipping I is effective in preventing pitting.

【0012】許容できるMnイオンの量のひとつのめや
すとして、発明者らは経験により、500ppm の上限を
設けた。 好ましくは、酸浴浸漬Iの酸液中のMnイオ
ン量が300〜400ppm を超えたら、この酸液を更新
する。 上述の機構から容易に考えられるとおり、酸浴
浸漬IIの酸液を電解回収した酸は、酸浴浸漬Iに戻さな
いことが望ましい。 従って、酸の電解回収・再使用を
する場合、IとIIの酸を合体させず、個別に処理をして
それぞれの酸浴槽に循環させるべきである。ただし、酸
浴浸漬IIの酸液においてもMn7+の量を高めることは好
ましくないから、Mnイオン量が1000ppm を超えた
ら、酸浴IIも新しく建浴しなおす必要がある。
As a rough guide to the allowable amount of Mn ions, the inventors have empirically established an upper limit of 500 ppm. Preferably, when the amount of Mn ions in the acid solution of Acid Bath Immersion I exceeds 300 to 400 ppm, the acid solution is renewed. As can be easily considered from the above mechanism, it is desirable that the acid obtained by electrolytically recovering the acid solution in the acid bath immersion II is not returned to the acid bath immersion I. Therefore, when electrolytically recovering and reusing the acids, the acids I and II should not be combined but treated separately and circulated in the respective acid baths. However, since it is not preferable to increase the amount of Mn 7+ even in the acid solution of the acid bath immersion II, it is necessary to newly rebuild the acid bath II when the Mn ion amount exceeds 1000 ppm.

【0013】[0013]

【実施例】下記の各槽を連続した脱スケール酸洗装置に
おいて、軸受鋼、構造用鋼、バネ鋼の線材(φ7〜44
mm)のコイルを、連続的に酸洗した。
EXAMPLES In a descaling and pickling apparatus in which each of the following tanks was continuously connected, a bearing steel, a structural steel, and a spring steel wire rod (φ7 to 44)
mm) coil was continuously pickled.

【0014】 1)酸浴浸漬I:10%H2SO4、60m3、60℃ 2)シャワー :散水 3)中和 :NaOH水溶液、常温 4)表面調整 :4%KMnO4+12%NaOH、8
5℃ 5)シャワー :散水 6)酸浴浸漬II:10%H2SO4、12m3、60℃ 7)シャワー :散水 8)被膜処理 :リン酸塩「ボンダリューベ」 酸液は、浴の自動分析を行なって、H2SO4量が所定の
値を下回ったときは一部を抜き出し、濾過してから電解
により再生し、槽に戻すようにした。 ロス分に応じて
新しい酸を補給することはいうまでもない。 H2SO4
の電解回収は、カチオン交換膜2枚をそなえた3室式電
解槽を使用して行ない、陽極液、陰極液とも脱泡(それ
ぞれO2ガス、H2ガスを含んでいる)をし、陰極液はさ
らに分離槽で固体(Feの酸化物、水酸化物)の沈降分
離を行なって、電解槽に循環させた。 酸液の抜き出し
量は、どちらも平均3m3/時である。
1) Acid bath immersion I: 10% H 2 SO 4 , 60 m 3 , 60 ° C. 2) Shower: Water spray 3) Neutralization: NaOH aqueous solution, room temperature 4) Surface preparation: 4% KMnO 4 + 12% NaOH, 8
5 ° C 5) Shower: Water sprinkling 6) Acid bath immersion II: 10% H 2 SO 4 , 12m 3 , 60 ° C 7) Shower: Water sprinkling 8) Coating treatment: Phosphate “Bonda Leube” Acid solution Analysis was carried out, and when the amount of H 2 SO 4 fell below a predetermined value, a part was extracted, filtered, regenerated by electrolysis, and returned to the tank. It goes without saying that new acid is replenished according to the loss. H 2 SO 4
The electrolytic recovery of was carried out using a three-chamber electrolysis cell equipped with two cation exchange membranes, defoaming the anolyte and catholyte (containing O 2 gas and H 2 gas, respectively) The liquid was further subjected to sedimentation separation of solids (Fe oxides and hydroxides) in a separation tank and circulated in the electrolytic tank. The average amount of acid solution withdrawn was 3 m 3 / hour in both cases.

【0015】酸浴浸漬IとIIとから抜き出した酸液を分
離せず一体にして電解処理して循環させた場合、酸浴浸
漬IのMnイオンの量は操業7日後に500ppm に達
し、建浴の必要が生じた。 両者を分離して別個に電解
処理し循環させたときは、操業30日後、酸浴浸漬Iの
Mnイオン濃度は500ppm 以下であったが、酸浴浸漬
IIのMnイオン濃度が1000ppm に達し、建浴が必要
になった。
When the acid solutions extracted from the acid bath immersions I and II are not separated but integrally electrolyzed and circulated, the amount of Mn ions in the acid bath immersion I reaches 500 ppm after 7 days of operation, The need for a bath arose. When both were separated and electrolyzed separately and circulated, the Mn ion concentration of the acid bath immersion I was 500 ppm or less after 30 days of operation,
The Mn ion concentration of II reached 1000 ppm and required a bath.

【0016】[0016]

【発明の効果】本発明に従って脱スケールの酸洗の酸浴
成分をコントロールすれば、硫酸酸洗の欠点であるピッ
チングの発生を回避して鋼材の脱スケール酸洗を実施す
ることができる。 とくに、酸浴浸漬IおよびIIの酸液
を別個に電解して酸を回収する好ましい態様によるとき
は、ピッチング発生を回避するための建浴の頻度を下げ
て、酸を十分に利用することができ、経済的であるとと
もに廃棄物の発生量を低減できる。
By controlling the acid bath components of the descaling pickling according to the present invention, the descaling pickling of steel can be carried out while avoiding the occurrence of pitting, which is a drawback of sulfuric acid pickling. Particularly in the case of the preferred embodiment in which the acid solutions of the acid bath dips I and II are separately electrolyzed to recover the acid, the frequency of the building bath for avoiding the occurrence of pitting may be reduced to sufficiently utilize the acid. In addition to being economical, the amount of waste generated can be reduced.

Claims (2)

【特許請求の範囲】[Claims] 【請求項1】 鋼材を硫酸浴で脱スケールする酸洗方法
であって、酸浴浸漬I−中和−表面調整−酸浴浸漬II−
被膜処理の諸工程からなる方法において、酸浴浸漬Iの
酸浴として、その中のMnイオンの合計量を500ppm
以下に規制したものを使用することを特徴とする脱スケ
ール酸洗方法。
1. A pickling method for descaling a steel material in a sulfuric acid bath, which comprises acid bath dipping I-neutralization-surface conditioning-acid bath dipping II-
In a method consisting of various steps of coating treatment, the total amount of Mn ions in the acid bath Immersion I is 500 ppm.
A descaling pickling method characterized by using the following regulated ones.
【請求項2】 使用後の酸液を電解処理して酸を分離回
収し循環再使用する脱スケール酸洗方法において、酸浴
浸漬Iの酸液と酸浴浸漬IIの酸液とを混合することなく
別個に処理し別個に循環させることを特徴とする請求項
1の脱スケール酸洗方法。
2. In a descaling pickling method in which an acid solution after use is electrolytically treated to separate and collect the acid, and is reused by circulation, the acid solution of acid bath immersion I and the acid solution of acid bath immersion II are mixed. The descaling pickling method according to claim 1, wherein the descaling pickling is performed separately and separately circulated.
JP17675094A 1994-07-28 1994-07-28 Descaling picking method Pending JPH0841666A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP17675094A JPH0841666A (en) 1994-07-28 1994-07-28 Descaling picking method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP17675094A JPH0841666A (en) 1994-07-28 1994-07-28 Descaling picking method

Publications (1)

Publication Number Publication Date
JPH0841666A true JPH0841666A (en) 1996-02-13

Family

ID=16019159

Family Applications (1)

Application Number Title Priority Date Filing Date
JP17675094A Pending JPH0841666A (en) 1994-07-28 1994-07-28 Descaling picking method

Country Status (1)

Country Link
JP (1) JPH0841666A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2012097336A (en) * 2010-11-04 2012-05-24 Kurita Engineering Co Ltd Scale removing method of chromium-containing steel material

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2012097336A (en) * 2010-11-04 2012-05-24 Kurita Engineering Co Ltd Scale removing method of chromium-containing steel material

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