JPS6138270B2 - - Google Patents
Info
- Publication number
- JPS6138270B2 JPS6138270B2 JP8617581A JP8617581A JPS6138270B2 JP S6138270 B2 JPS6138270 B2 JP S6138270B2 JP 8617581 A JP8617581 A JP 8617581A JP 8617581 A JP8617581 A JP 8617581A JP S6138270 B2 JPS6138270 B2 JP S6138270B2
- Authority
- JP
- Japan
- Prior art keywords
- pickling
- gold dust
- stainless steel
- hydrochloric acid
- seconds
- 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.)
- Expired
Links
- 238000005554 pickling Methods 0.000 claims description 40
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims description 37
- 241000430525 Aurinia saxatilis Species 0.000 claims description 28
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 claims description 22
- 229910000831 Steel Inorganic materials 0.000 claims description 20
- 239000010959 steel Substances 0.000 claims description 20
- 229910017604 nitric acid Inorganic materials 0.000 claims description 17
- 229910001220 stainless steel Inorganic materials 0.000 claims description 17
- 238000000034 method Methods 0.000 claims description 15
- 230000007797 corrosion Effects 0.000 claims description 13
- 238000005260 corrosion Methods 0.000 claims description 13
- 238000007654 immersion Methods 0.000 claims description 13
- 239000010935 stainless steel Substances 0.000 claims description 5
- 238000010438 heat treatment Methods 0.000 claims description 4
- 238000005422 blasting Methods 0.000 claims description 2
- JULDKEYYPIYHLQ-UHFFFAOYSA-N 3-hydroxy-2-[[2-[(3-hydroxy-4-oxopyran-2-yl)methyl-methylamino]ethyl-methylamino]methyl]pyran-4-one Chemical compound O1C=CC(=O)C(O)=C1CN(C)CCN(C)CC=1OC=CC(=O)C=1O JULDKEYYPIYHLQ-UHFFFAOYSA-N 0.000 claims 1
- 238000000137 annealing Methods 0.000 description 16
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 description 14
- 238000012360 testing method Methods 0.000 description 10
- 239000010960 cold rolled steel Substances 0.000 description 8
- 229910001105 martensitic stainless steel Inorganic materials 0.000 description 8
- 238000010306 acid treatment Methods 0.000 description 7
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 7
- 238000005098 hot rolling Methods 0.000 description 6
- 125000000391 vinyl group Chemical group [H]C([*])=C([H])[H] 0.000 description 6
- 229920002554 vinyl polymer Polymers 0.000 description 6
- 238000005097 cold rolling Methods 0.000 description 5
- 239000007788 liquid Substances 0.000 description 4
- 238000005498 polishing Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 3
- 229910000734 martensite Inorganic materials 0.000 description 3
- 230000006866 deterioration Effects 0.000 description 2
- 238000001000 micrograph Methods 0.000 description 2
- 239000011253 protective coating Substances 0.000 description 2
- 238000005096 rolling process Methods 0.000 description 2
- 201000004384 Alopecia Diseases 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 230000003796 beauty Effects 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000007598 dipping method Methods 0.000 description 1
- 230000003676 hair loss Effects 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000009996 mechanical pre-treatment Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 150000002739 metals Chemical group 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 238000001878 scanning electron micrograph Methods 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 239000002436 steel type Substances 0.000 description 1
- 239000002344 surface layer Substances 0.000 description 1
- 230000000007 visual effect Effects 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
- C23G1/00—Cleaning or pickling metallic material with solutions or molten salts
- C23G1/02—Cleaning or pickling metallic material with solutions or molten salts with acid solutions
- C23G1/08—Iron or steel
- C23G1/085—Iron or steel solutions containing HNO3
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)
Description
本発明は粒界腐食起因による表面疵の発生を防
止するフエライト系およびマルテンサイト系ステ
ンレス熱延鋼帯の連続酸洗方法に関するものであ
る。
熱延後焼鈍されたフエライト系ステンレス鋼帯
およびマルテンサイト系ステンレス鋼帯の酸化ス
ケールの除去は、連続酸洗ラインでシヨツトプラ
スト等の機械的予備脱スケールを施した後、硝弗
酸に浸漬して表層を溶解するとともに残存スケー
ルを除去する方法が一般に行われている。ところ
が、硝、弗酸で酸洗すると、第１図の鋼帯表面の
走査型電子顕微鏡観察写真に示すごとく、表面の
結晶粒界が溝状に腐食され、これを冷延するとゴ
ールドダストと称される微小ヘゲが発生する問題
がある。
ゴールドダストは冷延仕上げのままでは表面が
平滑であつて、第２図の100倍の顕微鏡写真にお
いてもその存在が判明せず、鋼板の保護ビニール
被膜を剥離してはじめて第３図の100倍の顕微鏡
写真に示すように微小ヘゲ疵の存在が認められる
ものである。これらゴールドダストは反射光によ
つてきらきらと光るとともに手触りも不良で、ス
テンレス鋼の商品価値を著しく悪化させる原因の
一つとなつている。このようにゴールドダストは
冷延仕上げ状態ではその存在を発見できない極め
て厄介な表面欠陥である。また、ゴールドダスト
の存在により鋼板表面に層状間隔を形成し、ステ
ンレス鋼本来の特性である耐銹性を阻害すること
にもなるので、ゴールドダストの発生のないステ
ンレス鋼板の提供が切望されていた。
その対策として従来は酸洗工程後熱延鋼帯をベ
ルトグラインダー研摩して粒界腐食部を除去して
いた。しかしながら、この研摩作業には研摩材料
の消費と研摩ロスを判い製造コストが高騰するこ
とが避けられないばかりでなく、研摩作業そのも
のが本質的なゴールドダストの発生防止対策でな
い欠点があつた。
本発明の目的は、フエライト系ステンレスおよ
びマルテンサイト系ステンレス冷延鋼帯に発生す
る粒界腐食起因のゴールドダストを本質的に防止
することができる連続酸洗方法を提供しようとす
るものである。
本発明によれば、酸洗時に粒界腐食に起因する
ゴールドダストの発生を防止するに際し、熱延さ
れた鋼帯に熱処理を施した後または熱処理を施す
ことなくシヨツトブラスト等の機械的予備脱スケ
ールを施し、まず５〜20％の希塩酸で20〜80秒間
浸漬酸洗し、次いで５〜13％の希硝酸で20〜40秒
間浸漬酸洗することにより、上記目的を達成する
ことができる。
本発明者等は、フエライト系ステンレスの代表
鋼であるSUS430の熱延板を用い、焼鈍条件を
種々変化させた時の各種酸液中における酸洗性と
冷延後のゴールドダストの発生程度を調査した。
その結果を表１に示す。表１に示す試験におい
て、ゴールドダスト発生数は供試鋼板表面にビニ
ールテープを粘着した後、このテープを剥離し、
鋼板表面に発生したゴールドダストの数を目視に
より数える方法をとつた。また、酸洗性は目視に
よる表面状況の観察、顕微鏡による粒界腐食の観
察およびJIS Ｚ 2371に規定される塩水噴霧試験
による耐発銹性を調べて評価した。また、酸洗工
程の処理条件は以下の通りである。
(1) 硝・弗酸処理条件
15％HNO3＋３％HF（60℃）、60秒浸漬
(2) 塩酸処理条件
20％HCl（60℃）、60秒浸漬
(3) 硝酸処理条件
10％HNO3（60℃）、30秒浸漬
表１から明らかなとおり、従来法の硝・弗酸処
理の場合No.1の例に示すごとく通常の焼鈍でも
軽度ではあるが粒界腐食を生じており、特に
No.2、３の例のように高温焼鈍するかまたは焼
鈍を全くしない時に粒界腐食が著しく、ゴールド
ダストが頻発する。これに対し、No.4〜９の例
に示すごとく塩酸酸洗した場合焼鈍状態に関係な
く粒界腐食は認められず、ゴールドダストが殆ん
ど発生しないことが確認された。しかし、No.7
〜９の例に示すごとく塩酸単独酸洗では酸洗後耐
銹性に劣ることがわかる。この対策としては、
No.4〜６の例に示すごとく塩酸酸洗後さらに硝
酸酸洗を施すことにより解決され、同時に酸洗後
表面の仕上り色調もより一層向上することも確認
された。なお、No.6の例に示すごとく未焼鈍板
を塩酸酸洗後硝酸酸洗した場合は酸洗面の耐銹性
が劣つているが、これを冷延後焼鈍および酸洗仕
上げすれば良好な耐銹性を有する面が得られた。
The present invention relates to a continuous pickling method for hot-rolled ferritic and martensitic stainless steel strips that prevents the occurrence of surface flaws due to intergranular corrosion. Oxidation scale on ferritic stainless steel strips and martensitic stainless steel strips that have been annealed after hot rolling can be removed by mechanical preliminary descaling such as shotplast in a continuous pickling line, and then immersion in nitric hydrofluoric acid. A commonly used method is to dissolve the surface layer and remove remaining scale. However, when pickling with nitric acid or hydrofluoric acid, the grain boundaries on the surface corrode in the form of grooves, as shown in the scanning electron microscope photograph of the steel strip surface in Figure 1. There is a problem in that minute baldness occurs. Gold dust has a smooth surface when it is cold-rolled, and its presence cannot be seen even in the 100x micrograph shown in Figure 2, and the 100x image shown in Figure 3 cannot be seen until the protective vinyl coating on the steel plate is peeled off. As shown in the photomicrograph, the presence of minute scratches is recognized. These gold dusts sparkle when reflected by light and have a poor feel to the touch, and are one of the causes of a significant deterioration in the commercial value of stainless steel. As described above, gold dust is an extremely troublesome surface defect that cannot be detected in the cold-rolled finished state. In addition, the presence of gold dust forms layered gaps on the surface of the steel sheet, impairing the rust resistance that is an inherent characteristic of stainless steel, so there has been a strong desire to provide a stainless steel sheet that does not generate gold dust. . As a countermeasure, conventionally, after the pickling process, the hot rolled steel strip was polished with a belt grinder to remove intergranular corrosion areas. However, this polishing operation not only unavoidably increases manufacturing costs due to the consumption of polishing materials and polishing losses, but also has the disadvantage that the polishing operation itself is not an essential measure to prevent the generation of gold dust. An object of the present invention is to provide a continuous pickling method that can essentially prevent gold dust caused by intergranular corrosion occurring in cold-rolled steel strips of ferritic stainless steel and martensitic stainless steel. According to the present invention, in order to prevent the generation of gold dust due to intergranular corrosion during pickling, mechanical preliminary work such as shot blasting is carried out after or without heat treatment on a hot rolled steel strip. The above purpose can be achieved by descaling, first immersion pickling in 5-20% dilute hydrochloric acid for 20-80 seconds, and then immersion pickling in 5-13% dilute nitric acid for 20-40 seconds. . The present inventors used hot-rolled sheets of SUS430, a representative steel of ferritic stainless steel, to investigate the pickling properties in various acid solutions and the degree of gold dust generation after cold rolling when various annealing conditions were changed. investigated.
The results are shown in Table 1. In the test shown in Table 1, the number of gold dust generated was measured by attaching vinyl tape to the surface of the test steel plate and then peeling off the tape.
A method was used to visually count the number of gold dust generated on the surface of the steel plate. In addition, pickling properties were evaluated by visual observation of the surface condition, observation of intergranular corrosion using a microscope, and rust resistance by a salt spray test specified in JIS Z 2371. Further, the processing conditions of the pickling step are as follows. (1) Nitric/hydrofluoric acid treatment conditions 15%HNO 3 +3%HF (60℃), 60 seconds immersion (2) Hydrochloric acid treatment conditions 20%HCl (60℃), 60 seconds immersion (3) Nitric acid treatment conditions 10%HNO 3 (60℃), immersion for 30 seconds As is clear from Table 1, in the case of conventional nitric/hydrofluoric acid treatment, intergranular corrosion occurs, albeit mildly, even with normal annealing, as shown in example No. 1. especially
As in Examples No. 2 and 3, when high-temperature annealing or no annealing is performed, intergranular corrosion is significant and gold dust frequently occurs. On the other hand, when the samples were pickled with hydrochloric acid as shown in Examples Nos. 4 to 9, intergranular corrosion was not observed regardless of the annealing state, and it was confirmed that almost no gold dust was generated. However, No.7
As shown in Examples 1 to 9, it can be seen that pickling with hydrochloric acid alone results in poor rust resistance after pickling. As a countermeasure for this,
As shown in Examples Nos. 4 to 6, the problem was solved by further performing nitric acid pickling after hydrochloric acid pickling, and at the same time, it was confirmed that the finished color tone of the surface after pickling was further improved. As shown in example No. 6, when an unannealed plate is pickled with hydrochloric acid and then pickled with nitric acid, the rust resistance of the pickled plate is poor, but it can be improved by annealing and finishing with pickling after cold rolling. A surface with rust resistance was obtained.
【表】【table】
【表】
マルテンサイト系ステンレスの代表鋼である
SUS 410について各種酸洗液中における酸洗性と
冷延後のゴールドダストの発生程度を試験した結
果を表２に示す。表２に示す試験はフエライト系
ステンレスにつき前述した試験と同様にして行つ
た。なお、酸洗処理条件は以下の通りであつた。
(1) 硝・弗酸処理条件
８％HNO3＋２％HF（60℃）、30秒浸漬
(2) 塩酸処理条件
10％HCl（60℃）、30秒浸漬
(3) 硝酸処理条件
10％HNO3（50℃）、30秒浸漬
下表２から明らかなように、マルテンサイト系
ステンレス鋼の場合もフエライト系ステンレス鋼
と同様に、熱処理の有無にかかわらず、塩酸酸洗
後硝酸酸洗を施すことにより、酸洗面の仕上がり
状況は非常に良好で、粒界腐食は認められず、冷
延後ゴールドダストの発生をほぼ完全に防止でき
ることが確認された。[Table] Representative martensitic stainless steel
Table 2 shows the results of testing the pickling properties of SUS 410 in various pickling solutions and the degree of gold dust generation after cold rolling. The tests shown in Table 2 were conducted on ferritic stainless steel in the same manner as the tests described above. Note that the pickling treatment conditions were as follows. (1) Nitric/hydrofluoric acid treatment conditions: 8% HNO 3 +2% HF (60℃), immersion for 30 seconds (2) Hydrochloric acid treatment conditions: 10% HCl (60℃), immersion for 30 seconds (3) Nitric acid treatment conditions: 10% HNO 3 (50℃), immersion for 30 seconds As is clear from Table 2 below, similarly to ferritic stainless steel, martensitic stainless steel is subjected to hydrochloric acid pickling followed by nitric acid pickling, regardless of heat treatment. As a result, the finish of the pickled steel was very good, no intergranular corrosion was observed, and it was confirmed that the generation of gold dust after cold rolling could be almost completely prevented.
【表】
本発明の適用に関し、フエライト系ステンレス
鋼としては、SUS430、434、446など、マルテン
サイト系ステンレス鋼としては、SUS410、
420J2、440Aなど全てに好適であり、いずれの鋼
の場合も熱延工程は特に限定されるものではな
く、既知の通常条件によつて行うことができる。
熱延後の焼鈍は次に示す焼鈍条件において特に
有効に作用する。
(1) JIS Ｇ 4306に規定されるフエライト系およ
びマルテンサイト系ステンレス熱延鋼帯に通常
施される焼鈍。
(2) フエライト系ステンレス鋼に対するリジング
発生軽減対策として知られているA1点以上の
温度に加熱する高温焼鈍。
(3) フエライト系およびマルテンサイト系ステン
レス鋼を熱延後放射を極力抑制して主に自己保
有熱により行なう通常よりも低温の焼鈍。
(4) フエライト系およびマルテンサイト系ステン
レス鋼を熱延後特に焼鈍を施さない方法。
熱延焼鈍後の脱スケールはシヨツトプラスト、
軽圧延、曲げロール等の機械的予備処理と、塩酸
に次ぐ硝酸酸洗を組み合わせる方法によつて行わ
れる。塩酸酸洗における濃度および液温条件は鋼
種あるいは酸化スケール生成状況によつて異なる
が、実際の連続酸洗工程での酸洗所要時間はせい
ぜい２分であるから、その時間内に酸洗できるよ
うに条件を決定すべきである。その条件として好
適例を挙げると表３に示すようになる。[Table] Regarding the application of the present invention, examples of ferritic stainless steel include SUS430, 434, and 446, and examples of martensitic stainless steel include SUS410,
It is suitable for all steels such as 420J2 and 440A, and the hot rolling process is not particularly limited for any of the steels, and can be carried out under known normal conditions. Annealing after hot rolling works particularly effectively under the following annealing conditions. (1) Annealing normally applied to ferritic and martensitic stainless hot rolled steel strips specified in JIS G 4306. (2) High-temperature annealing that heats ferritic stainless steel to a temperature above point A, which is known as a measure to reduce the occurrence of ridging. (3) After hot-rolling ferritic and martensitic stainless steels, annealing is performed at a lower temperature than usual, using mainly self-retained heat to suppress radiation as much as possible. (4) A method in which ferritic and martensitic stainless steels are not annealed after hot rolling. Shotplast is used for descaling after hot rolling annealing.
It is carried out by a method that combines mechanical pretreatment such as light rolling and bending rolls, and pickling with hydrochloric acid and then nitric acid. The concentration and liquid temperature conditions for hydrochloric acid pickling vary depending on the steel type and oxide scale formation status, but in actual continuous pickling process the time required for pickling is at most 2 minutes, so pickling can be completed within that time. The conditions should be determined accordingly. Preferred examples of the conditions are shown in Table 3.
【表】
塩酸酸洗条件は、５％以上20％以下の希塩酸で
20〜80秒間浸漬処理する必要があり、各々下限未
満では酸洗効果がなく、上限をこえては粒界腐食
が顕著となり、ゴールドダスト原因となる。ま
た、硝酸酸洗条件は、５〜13％の希硝酸で20〜40
秒間浸漬処理する必要があり、各々下限未満では
耐銹性劣化防止効果が少なく、上限を越えては粒
界腐食が顕著となるので好ましくない。塩酸酸洗
後の耐銹性改善策としての硝酸酸洗条件は、フエ
ライト系ステンレス鋼では、５〜15％HNO3で液
温50〜65℃、マルテンサイト系ステンレス鋼で
は、５〜13％HNO3で液温35〜60℃の範囲が好適
である。浸漬時間はいずれの鋼も20〜40秒程度が
望ましい。なお、HNO3濃度および液温がこれ以
上になるとNOxガスが発生するので注意を要す
る。酸洗後の冷延工程は特に制限されず、既知の
方法で行うことができる。以下、本発明方法を好
適実施例につき説明する。
実施例 １
板厚４mmのJIS規格SUS410、420J2の熱延鋼帯
を通常の焼鈍温度750℃で５時間焼鈍後、シヨツ
トプラストにより予備脱スケールし、次いで塩酸
および硝酸の順に酸洗後1.5mmに冷延し、その後
焼鈍、酸洗により2D仕上げの冷延鋼帯を製造し
た。この冷延鋼帯のビニールテープによるゴール
ドダスト試験を行なつたが、ゴールドダストの発
生は認められなかつた。
実施例 ２
板厚３mmのJIS規格SUS430の熱延鋼帯を通常の
焼鈍温度800℃で10時間焼鈍後、シヨツトプラス
トにより予備脱スケールし、次いで塩酸および硝
酸の順に酸洗後0.4mmに冷延し、その後光輝焼鈍
炉によりBA仕上げの冷延鋼帯を製造した。この
冷延鋼帯のビニールテープによるゴールドダスト
発生試験を行なつたが、ゴールドダストの発生は
全然認められなかつた。
さらに、この鋼帯に表面保護被膜（SG）を張
つた後、）業務用冷蔵庫の外板に取り付けた。そ
の後表面保護被膜（SG）を剥離したが、ゴール
ドダストの発生は認められず、ステンレス鋼の美
麗さは何ら損われていないことが確認された。
実施例 ３
板厚３mmのJIS規格SUS410、430の熱延、未焼
鈍鋼帯をシヨツトプラストにより予備脱スケール
し、次いで塩酸および硝酸の順に酸洗後0.7mmに
冷延し、その後焼鈍、酸洗により2D仕上げの冷
延鋼帯を製造した。この冷延鋼帯のビニールテー
プによるゴールドダスト発生試験を行なつたが、
ゴールドダストの発生はほとんど見られず、また
実際の使用上においても特に問題のないことが確
認された。本発明によるフエライト系およびマル
テンサイト系ステンレス冷延鋼帯における粒界腐
食起因のゴールドダストの発生防止法は、熱延鋼
帯の酸洗方法を塩酸次いで硝酸とすることにより
次のような効果をあげることができる。
(1) ゴールドダストの発生は殆んど皆無の状態で
表面性状が極めて良好である。
(2) 塩酸に次ぐ硝酸酸洗の場合、従来の硝、弗酸
法のようにNOxガスの発生がないので排ガス
処理設備が簡単であるとともに、その実施が容
易である。
(3) 本発明によるゴールドダストの防止法は、従
来の皮相的なものではなく、本質的なものであ
つて実効が顕著である。[Table] Hydrochloric acid pickling conditions are 5% to 20% diluted hydrochloric acid.
It is necessary to perform the immersion treatment for 20 to 80 seconds, and below each lower limit, there is no pickling effect, and above the upper limit, intergranular corrosion becomes noticeable and causes gold dust. In addition, the nitric acid pickling conditions are 20 to 40% dilute nitric acid of 5 to 13%.
It is necessary to perform a dipping treatment for seconds, and if the lower limit is less than the respective lower limit, the rust resistance deterioration prevention effect will be small, and if the upper limit is exceeded, intergranular corrosion will become noticeable, which is not preferable. The conditions for pickling with nitric acid as a measure to improve rust resistance after hydrochloric acid pickling are 5-15% HNO 3 and a liquid temperature of 50-65°C for ferritic stainless steel, and 5-13% HNO for martensitic stainless steel. 3 and a liquid temperature in the range of 35 to 60°C is suitable. The immersion time for all steels is preferably about 20 to 40 seconds. Note that if the HNO 3 concentration and liquid temperature exceed these values, NOx gas will be generated, so care must be taken. The cold rolling step after pickling is not particularly limited, and can be performed by a known method. The method of the present invention will now be described with reference to preferred embodiments. Example 1 Hot-rolled steel strips of JIS standard SUS410 and 420J2 with a plate thickness of 4 mm were annealed at the normal annealing temperature of 750°C for 5 hours, preliminarily descaled by shotplast, then pickled with hydrochloric acid and nitric acid in that order, and cooled to 1.5 mm. A cold-rolled steel strip with a 2D finish was produced by rolling, followed by annealing and pickling. A gold dust test was conducted using a vinyl tape on this cold rolled steel strip, but no gold dust was observed. Example 2 A hot rolled steel strip of JIS standard SUS430 with a thickness of 3 mm was annealed at the normal annealing temperature of 800°C for 10 hours, preliminarily descaled by shotplast, then pickled in hydrochloric acid and nitric acid in that order, and cold rolled to 0.4 mm. Then, a cold rolled steel strip with BA finish was produced using a bright annealing furnace. A gold dust generation test was conducted using a vinyl tape on this cold rolled steel strip, but no gold dust generation was observed. Furthermore, after applying a surface protective coating (SG) to this steel strip, it was attached to the outer panel of a commercial refrigerator. After that, the surface protective coating (SG) was removed, but no gold dust was observed, confirming that the beauty of the stainless steel was not impaired in any way. Example 3 A hot-rolled, unannealed steel strip of JIS standard SUS410 or 430 with a thickness of 3 mm was preliminarily descaled by shotplast, then pickled in hydrochloric acid and nitric acid in that order, cold rolled to 0.7 mm, and then annealed and pickled. A cold-rolled steel strip with 2D finishing was produced. A gold dust generation test was conducted using vinyl tape on this cold-rolled steel strip.
Almost no gold dust was observed, and it was confirmed that there were no particular problems in actual use. The method for preventing the generation of gold dust caused by intergranular corrosion in cold-rolled ferritic and martensitic stainless steel strips according to the present invention achieves the following effects by pickling hot-rolled steel strips using hydrochloric acid and then nitric acid. I can give it to you. (1) The surface quality is extremely good with almost no gold dust. (2) In the case of nitric acid pickling, which follows hydrochloric acid, no NOx gas is generated unlike the conventional nitric and hydrofluoric acid methods, so the exhaust gas treatment equipment is simple and it is easy to implement. (3) The method for preventing gold dust according to the present invention is not a conventional method that is superficial, but is essential and has remarkable effectiveness.
添付図面は金属の表面組成を表わす顕微鏡写真
であつて、第１図は従来の硝、弗酸法で酸洗され
た熱延焼鈍鋼帯表面の走査型電子顕微鏡による
700倍拡大写真、第２図は冷延鋼帯表面の顕微鏡
による100倍拡大写真、第３図は第２図と同一場
所をビニールテープ剥離試験して発生したゴール
ドダストを示す顕微鏡による100倍拡大写真であ
る。
The attached drawings are micrographs showing the surface composition of metals, and Figure 1 is a scanning electron micrograph of the surface of a hot-rolled annealed steel strip that has been pickled using the conventional nitric and hydrofluoric acid method.
700x magnification photo, Figure 2 is a 100x magnification photo of the cold rolled steel strip surface taken with a microscope, and Figure 3 is a 100x magnification photo taken with a microscope showing gold dust generated during a vinyl tape peel test at the same location as in Figure 2. It's a photo.
Claims (1)
の発生を防止するに際し、熱延された鋼帯に熱処
理を施した後または熱処理を施すことなくシヨツ
トブラスト等の機械的予備脱スケールを施し、ま
ず５〜20％の希塩酸で20〜80秒間浸漬酸洗し、次
いで５〜13％の希硝酸で20〜40秒間浸漬酸洗する
ことを特徴とする表面疵の発生を防止するフエラ
イト系およびマルテンサイト系ステンレス熱帯鋼
体の連続酸洗方法。1. In order to prevent the generation of gold dust due to intergranular corrosion during pickling, mechanical preliminary descaling such as shot blasting is applied to the hot rolled steel strip after heat treatment or without heat treatment, Ferritic and malten to prevent surface flaws, characterized by first immersion pickling in 5-20% diluted hydrochloric acid for 20-80 seconds, then immersion pickling in 5-13% diluted nitric acid for 20-40 seconds. Continuous pickling method for site-based tropical stainless steel bodies.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8617581A JPS57200573A (en) | 1981-06-04 | 1981-06-04 | Continuous pickling method of ferrite and martensite stainless hot rolled steel band for preventing surface from being flawed |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8617581A JPS57200573A (en) | 1981-06-04 | 1981-06-04 | Continuous pickling method of ferrite and martensite stainless hot rolled steel band for preventing surface from being flawed |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS57200573A JPS57200573A (en) | 1982-12-08 |
| JPS6138270B2 true JPS6138270B2 (en) | 1986-08-28 |
Family
ID=13879415
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP8617581A Granted JPS57200573A (en) | 1981-06-04 | 1981-06-04 | Continuous pickling method of ferrite and martensite stainless hot rolled steel band for preventing surface from being flawed |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS57200573A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6391974U (en) * | 1986-12-05 | 1988-06-14 |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS60130414A (en) * | 1983-12-20 | 1985-07-11 | Mitsubishi Heavy Ind Ltd | Descaling method of steel strip |
| KR101316393B1 (en) * | 2011-08-10 | 2013-10-08 | 주식회사 포스코 | Eco-friendly scale removing system of martensitic stainless steel sheet and method for manufacturing martensitic stainless steel sheet using the same |
| JP6173514B1 (en) * | 2016-03-24 | 2017-08-02 | 日新製鋼株式会社 | Manufacturing method of ferritic stainless steel sheet |
| CN109594085A (en) * | 2018-12-05 | 2019-04-09 | 敬业钢铁有限公司 | A kind of hot rolled steel plate derusting method |
| CN110814032B (en) * | 2019-10-18 | 2021-11-19 | 甘肃酒钢集团宏兴钢铁股份有限公司 | Cold rolling method for 2B surface 439 ferritic stainless steel |
-
1981
- 1981-06-04 JP JP8617581A patent/JPS57200573A/en active Granted
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6391974U (en) * | 1986-12-05 | 1988-06-14 |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS57200573A (en) | 1982-12-08 |
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