JP3371061B2 - Method of manufacturing cold rolled steel strip by rolling before pickling - Google Patents
Method of manufacturing cold rolled steel strip by rolling before picklingInfo
- Publication number
- JP3371061B2 JP3371061B2 JP26922896A JP26922896A JP3371061B2 JP 3371061 B2 JP3371061 B2 JP 3371061B2 JP 26922896 A JP26922896 A JP 26922896A JP 26922896 A JP26922896 A JP 26922896A JP 3371061 B2 JP3371061 B2 JP 3371061B2
- Authority
- JP
- Japan
- Prior art keywords
- steel strip
- pickling
- scale
- rolling
- rolled steel
- 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 - Lifetime
Links
- 238000005554 pickling Methods 0.000 title claims description 60
- 239000010960 cold rolled steel Substances 0.000 title claims description 11
- 238000004519 manufacturing process Methods 0.000 title claims 3
- 238000005096 rolling process Methods 0.000 title description 53
- 229910000831 Steel Inorganic materials 0.000 claims description 80
- 239000010959 steel Substances 0.000 claims description 80
- 230000001680 brushing effect Effects 0.000 claims description 13
- 239000007921 spray Substances 0.000 claims description 10
- 238000005097 cold rolling Methods 0.000 description 20
- 239000010410 layer Substances 0.000 description 17
- 238000000034 method Methods 0.000 description 9
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 8
- 239000002436 steel type Substances 0.000 description 7
- 230000007547 defect Effects 0.000 description 6
- 239000000463 material Substances 0.000 description 6
- 238000000137 annealing Methods 0.000 description 5
- 238000010438 heat treatment Methods 0.000 description 5
- 239000002253 acid Substances 0.000 description 4
- 230000002093 peripheral effect Effects 0.000 description 4
- 238000005507 spraying Methods 0.000 description 4
- 239000006061 abrasive grain Substances 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- 238000005452 bending Methods 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 230000003247 decreasing effect Effects 0.000 description 2
- 238000004299 exfoliation Methods 0.000 description 2
- 239000012634 fragment Substances 0.000 description 2
- 239000010985 leather Substances 0.000 description 2
- 102200110702 rs60261494 Human genes 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 229910000532 Deoxidized steel Inorganic materials 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 229910000655 Killed steel Inorganic materials 0.000 description 1
- 238000010306 acid treatment Methods 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 238000005422 blasting Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000032798 delamination Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000008030 elimination Effects 0.000 description 1
- 238000003379 elimination reaction Methods 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000001953 recrystallisation Methods 0.000 description 1
- 239000002344 surface layer Substances 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
- 229910000859 α-Fe Inorganic materials 0.000 description 1
Landscapes
- Cleaning In General (AREA)
- Metal Rolling (AREA)
- Heat Treatment Of Strip Materials And Filament Materials (AREA)
- Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は、酸洗前の高圧下圧延に
よってスケールを機械的に除去すると共に、必要な特性
を作り込んだ冷延鋼帯を製造する方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for mechanically removing scale by high-pressure rolling before pickling and producing a cold-rolled steel strip having necessary properties.
【０００２】[0002]
【従来の技術】熱間圧延された鋼帯は、酸化物を主体と
するスケールで表面が覆われている。この熱延鋼帯を、
そのまま冷延等の下工程に送ると、熱延スケールに起因
する表面疵やクラック等の欠陥が発生する原因となる。
そこで、通常、酸洗によって熱延スケールを除去し、熱
延鋼帯を下工程に搬送している。この方法では、酸洗設
備，廃酸処理，脱スケール能の調整等の点で問題があ
り、また酸洗時に発生する水素の侵入によって鋼材の特
性が劣化する虞れもある。酸洗に起因する諸問題を解決
するため、酸洗工程に送り込まれる熱延鋼帯のスケール
を除去する方法が種々検討されている。たとえば、スケ
ールが付着した熱延鋼帯を高圧下率で冷間圧延すること
（以下、黒皮圧延という）が特公昭５４−１３３４６０
号公報，特開昭５７−４１８２１号公報，特開昭５７−
１０９１７号公報等で紹介されている。高圧下率の冷間
圧延により、スケールに亀裂が発生し、また鋼帯に対す
る付着力が低下するので、ショットブラスト，高圧水噴
射，ブラッシング，砥粒研削等により冷間圧延後の鋼帯
から容易に分離される。その結果、酸洗槽に搬入される
熱延鋼帯に付着しているスケールが少なくなり、酸洗工
程の負荷が軽減する。2. Description of the Related Art The surface of a hot-rolled steel strip is covered with a scale mainly composed of oxide. This hot rolled steel strip
If it is sent to a lower step such as cold rolling as it is, it may cause defects such as surface flaws and cracks due to the hot rolled scale.
Therefore, the hot-rolled scale is usually removed by pickling, and the hot-rolled steel strip is transported to the lower step. This method has a problem in terms of pickling equipment, waste acid treatment, adjustment of descaling ability, and the like, and there is a possibility that the characteristics of the steel material may be deteriorated by the penetration of hydrogen generated during pickling. In order to solve various problems caused by pickling, various methods for removing the scale of the hot-rolled steel strip fed into the pickling process have been studied. For example, cold-rolling a hot-rolled steel strip with scale attached thereto at a high-pressure reduction rate (hereinafter referred to as black-skin rolling) is disclosed in Japanese Examined Patent Publication No. 54-133460.
JP-A-57-41821, JP-A-57-41821
It is introduced in Japanese Patent No. 10917. Cold rolling at a high pressure ratio causes cracks in the scale and reduces the adhesion to the steel strip, so shot blasting, high-pressure water jetting, brushing, abrasive grain grinding, etc. can be performed easily from the steel strip after cold rolling. Is separated into As a result, the scale attached to the hot rolled steel strip carried into the pickling tank is reduced, and the load of the pickling step is reduced.
【０００３】[0003]
【発明が解決しようとする課題】熱延鋼帯を高圧下率で
黒皮圧延するとき、確かに酸洗工程の負荷が軽減される
ものの、鋼帯表面から剥離したスケールの破片が鋼帯表
面に付着・残存し易い。この場合のスケールは、熱延鋼
帯をテンションレベラーに通板したときに生じるスケー
ルと異なり、鋼帯表面に対する密着性が強い。そのた
め、酸洗槽に送り込まれるスケールが多く、予期したほ
どに酸洗負荷を軽減することができない。しかも、高圧
下圧延で熱延鋼帯から剥離したスケールの破片が鋼帯表
面に圧着され、或いは押し込まれ、酸洗工程での除去が
困難になり、後続する冷間圧延工程で表面疵等の欠陥を
発生させる原因となり易い。そのため、たとえば砥粒研
削等によってスケール破片を除去しているが、依然とし
て鋼帯表面に残留するものがある。When black-rolling a hot-rolled steel strip at a high pressure reduction rate, the load of the pickling step is certainly reduced, but the scale fragments peeled from the steel strip surface are the steel strip surface. Easily adheres to and remains on. The scale in this case has strong adhesion to the surface of the steel strip, unlike the scale produced when the hot-rolled steel strip is passed through the tension leveler. Therefore, many scales are sent to the pickling tank, and the pickling load cannot be reduced as expected. Moreover, the scale fragments separated from the hot-rolled steel strip by high-pressure rolling are pressure-bonded to the steel strip surface or pushed into the steel strip, making it difficult to remove in the pickling process, and causing surface defects such as surface defects in the subsequent cold rolling process. It is likely to cause defects. Therefore, although scale debris is removed by, for example, abrasive grain grinding or the like, some remains on the surface of the steel strip.
【０００４】本発明者等は、酸洗負荷の軽減に有効であ
る黒皮圧延の長所を活かすことを狙って、製品に表面疵
を発生させる残留スケールに対する対策を種々検討し
た。その結果、黒皮圧延後の鋼帯表面をブラッシングす
るとき残留スケールのほぼ全量が除去されること、また
圧延機のワークロールに熱延鋼帯から転写されたスケー
ル片をポリッシャー，高圧水スプレー，スクレーパ等で
取り除くとき、鋼帯表面に残留するスケール自体も大幅
に少なくなることを見い出し、別途出願した。このよう
にして、酸洗前の圧延で効率よくディスケーリングし、
酸洗槽に持ち込まれるスケールを減少させるとき、酸洗
負荷が軽減される。本発明は、ディスケーリングに有効
な酸洗前圧延を更に発展させたものであり、酸洗前圧延
によって必要な特性を作り込み、酸洗後に熱処理するだ
けで、或いは軽度の冷間圧延を施すだけで、要求特性を
備えた冷延鋼板を得ることを目的とする。The present inventors have studied various measures against residual scale which causes surface defects in products, aiming to utilize the advantage of black leather rolling which is effective in reducing the pickling load. As a result, almost all of the residual scale is removed when brushing the surface of the steel strip after black leather rolling, and the scale pieces transferred from the hot rolled steel strip to the work roll of the rolling mill are polished, sprayed with high pressure water, We found that the scale itself that remained on the surface of the steel strip was significantly reduced when it was removed with a scraper, and filed separately. In this way, descaling is efficiently performed by rolling before pickling,
When reducing the scale brought into the pickling tank, the pickling load is reduced. The present invention is a further development of pre-pickling rolling effective for descaling, in which required properties are created by pre-pickling rolling, and only heat treatment after pickling or mild cold rolling is performed. The purpose is to obtain a cold-rolled steel sheet having the required characteristics.
【０００５】[0005]
【課題を解決するための手段】本発明のディスケーリン
グ方法は、その目的を達成するため、表面に熱延スケー
ルが付着している熱延鋼帯を４０〜５０％の圧下率で冷
間圧延し、鋼帯表面から剥離したスケール片をブラッシ
ング及びスプレーで除去した後、鋼帯を酸洗槽に搬入し
て残留スケールを酸洗除去し、次いで焼鈍することを特
徴とする。本発明に従ったラインは、図１に示すように
構築される。熱延スケールが付着したままの熱延鋼帯１
は、ペイオフリール２から巻き戻され、ブライドルロー
ル３を経て冷間圧延機４で高圧下圧延される。熱延スケ
ールは、高圧下圧延によって亀裂，粉砕され、鋼帯１か
ら剥離される。鋼帯表面に残留しているスケール粉砕物
をブラシ５で除去した後、更にスプレー装置６に導入さ
れ、スプレーノズル７から高圧水を吹き付けることによ
って鋼帯の表面が清浄化される。ここで、内部から高圧
水を噴射させる機能を備えたブラシ５を使用するとき、
スプレー装置６を省略することも可能である。このよう
に処理された鋼帯は、次いで酸洗槽８に送り込まれ、表
面に僅かに残っているスケールが酸洗除去される。In order to achieve the object, the descaling method of the present invention cold-rolls a hot-rolled steel strip having a hot-rolled scale attached to its surface at a reduction rate of 40 to 50%. Then, after removing the scale pieces separated from the surface of the steel strip by brushing and spraying, the steel strip is carried into a pickling tank to remove residual scale by pickling, and then annealed. The line according to the invention is constructed as shown in FIG. Hot rolled steel strip 1 with hot rolled scale attached
Is unwound from the payoff reel 2, passed through a bridle roll 3, and rolled under high pressure by a cold rolling mill 4. The hot-rolled scale is cracked and crushed by rolling under high pressure and peeled from the steel strip 1. After the scale pulverized material remaining on the surface of the steel strip is removed by the brush 5, it is further introduced into the spray device 6 and the surface of the steel strip is cleaned by spraying high-pressure water from the spray nozzle 7. Here, when using the brush 5 having a function of ejecting high-pressure water from the inside,
It is also possible to omit the spray device 6. The steel strip thus treated is then sent to the pickling tank 8 and the scale slightly remaining on the surface is pickled and removed.
【０００６】酸洗後の鋼帯は、そのまま熱処理工程に送
られ、焼鈍によって所定の結晶粒度で均一なフェライト
組織に調整される。或いは、巻取りリール９で一旦巻き
取り、別途の熱処理ラインで熱処理することも可能であ
る。また、場合によっては必要形状を出すために、軽度
の冷間圧延を施すこともある。冷間圧延機としては、ポ
リッシャー，スプレーノズル又はスクレーパを周面に対
向させたワークロールを備えたものが好ましい。この場
合、熱延鋼帯からワークロールの周面に転写された熱延
スケールの粉砕物は、圧延ロールの表面に対向配置した
ポリッシャー，スプレーノズル，スクレーパ等によって
ロール表面から除去され、系外に排出される。ポリッシ
ャー，スプレーノズル，スクレーパ等は、回転方向に関
して圧下点よりも下流側の位置でワークロールの周面に
対向配置することが好ましい。また、ワークロールに接
して回転するバックアップロールに対しても、同様なポ
リッシャー，スプレーノズル，スクレーパ等を設けても
よい。The steel strip after pickling is sent to the heat treatment step as it is, and is annealed to have a uniform ferrite structure with a predetermined grain size. Alternatively, it is also possible to temporarily wind the winding reel 9 and heat-treat it in a separate heat-treatment line. In some cases, light cold rolling may be performed to obtain a required shape. As the cold rolling mill, one provided with a work roll having a peripheral surface facing a polisher, a spray nozzle or a scraper is preferable. In this case, the hot-rolled scale crushed material transferred from the hot-rolled steel strip to the peripheral surface of the work roll is removed from the roll surface by a polisher, a spray nozzle, a scraper, etc., which are arranged facing the surface of the rolling roll, and then removed from the system. Is discharged. It is preferable that the polisher, the spray nozzle, the scraper, and the like are arranged facing the peripheral surface of the work roll at a position downstream of the rolling point in the rotation direction. Further, the same polisher, spray nozzle, scraper and the like may be provided for the backup roll which rotates in contact with the work roll.
【０００７】冷間圧延機４は、圧下率が４０〜５０％と
なるように調整される。このような高圧下率が熱延鋼帯
１のディスケーリングに有効である理由を、本発明者等
は次のように考察した。熱延鋼帯１の表面に形成されて
いるスケールは、主としてＦｅ3Ｏ4で構成されるが、概
念的には内部から表層に向かって酸素濃度が順次高くな
るＦｅＯ層，Ｆｅ3Ｏ4層及びＦｅ2Ｏ3層が基地鋼の表面
に積層された構造をもつものと考えられる。実際、急冷
された鋼帯ほどＦｅＯ層が厚くなる傾向がみられる。ス
ケール層は、弱脱酸鋼では６〜７μｍと比較的薄く、Ｔ
ｉキルド鋼では９〜１０μｍと比較的厚くなっている。The cold rolling mill 4 is adjusted so that the rolling reduction is 40 to 50%. The present inventors considered the reason why such a high pressure reduction is effective for descaling of the hot-rolled steel strip 1 as follows. The scale formed on the surface of the hot-rolled steel strip 1 is mainly composed of Fe 3 O 4 , but conceptually, the FeO layer, the Fe 3 O 4 layer in which the oxygen concentration gradually increases from the inside toward the surface layer. It is considered that the Fe 2 O 3 and Fe 2 O 3 layers are laminated on the surface of the base steel. In fact, there is a tendency for the FeO layer to become thicker for the quenched steel strip. The scale layer of the weakly deoxidized steel is 6 to 7 μm, which is relatively thin.
The i-killed steel has a relatively large thickness of 9 to 10 μm.
【０００８】スケール層の大半を占めるＦｅ3 Ｏ4 層及
びＦｅ2 Ｏ3 層は硬質で脆く、比較的低い圧下力でもク
ラックが入り易い。たとえば、酸洗の前工程として組み
込まれている従来のテンションレベラー程度の圧下力
（約２％）や機械的な繰返し曲げ加工でも、クラックが
入り剥離する。硫酸酸洗でみられるような機械的な繰返
し曲げを与える装置でも、Ｆｅ2 Ｏ3 層，Ｆｅ3 Ｏ4 層
に亀裂を付けることができる。これに対し、基地鋼との
界面にあるＦｅＯ層は、展延性があり、低い圧下率では
基地鋼の伸びに従って変形する。そのため、テンション
レベラー程度の圧下力で下地鋼から剥離せず、酸洗槽に
持ち込まれる。しかし、圧下率を高く設定すると、基地
鋼とＦｅＯ層との変形量の差が大きくなり、基地鋼の伸
びに追従できなくなったＦｅＯ層にクラックが発生す
る。実際、冷間圧延で熱延鋼帯表面から剥離したスケー
ルの粉砕物を調査してみると、圧下率が低いときには剥
離したスケールが粉粒状であるのに対し、圧下率の上昇
に伴って粉砕物のサイズが大きく鱗片状になってくるこ
とが観察される。この圧下率に応じた剥離スケールの状
態変化は、高圧下率の圧延になるほどスケール層の内
部，換言すればＦｅＯ層まで入ったクラックを起点とし
てスケール剥離が生じ、スケール剥離量が多くなる原因
であると推察される。その結果、圧延後の鋼帯表面に残
存するスケールが大幅に少なくなる。The Fe 3 O 4 layer and the Fe 2 O 3 layer, which occupy most of the scale layer, are hard and brittle, and are easily cracked even with a relatively low rolling force. For example, even if a rolling force (about 2%) of a conventional tension leveler, which is incorporated as a pre-step of pickling, or mechanical repeated bending work, cracks are generated and peeling occurs. The Fe 2 O 3 layer and the Fe 3 O 4 layer can be cracked even by a device that gives mechanical repeated bending as seen in sulfuric acid pickling. On the other hand, the FeO layer at the interface with the base steel is malleable and deforms according to the elongation of the base steel at a low rolling reduction. Therefore, it is brought into the pickling tank without being peeled off from the base steel by the rolling force of about the tension leveler. However, when the rolling reduction is set to be high, the difference in deformation amount between the base steel and the FeO layer becomes large, and cracks occur in the FeO layer that cannot follow the elongation of the base steel. In fact, when investigating the crushed product of the scale peeled from the surface of the hot-rolled steel strip by cold rolling, the peeled scale was powdery when the rolling reduction was low, but it was crushed as the rolling reduction increased. It is observed that the size of the object becomes large and scale-like. The state change of the exfoliation scale according to the rolling reduction is caused by an increase in the amount of scale exfoliation due to the crack starting from the inside of the scale layer, in other words, the crack entering the FeO layer, as the high pressure rolling is performed. It is speculated that there is. As a result, the scale remaining on the surface of the steel strip after rolling is significantly reduced.
【０００９】しかし、鱗片状で剥離したスケール片は、
鋼材表面に対する付着性が強く、鋼帯から剥離されたも
のであっても、圧延ロール表面に移し取られた後、再度
鋼帯表面に圧着又は押し込まれる場合もある。そこで、
本発明者等は、冷間圧延後の鋼帯表面をブラッシングす
ることにより鋼帯表面から残存スケールを除去すると共
に、圧延ロール表面に付着しているスケール片を除去す
る方法を試みた。その結果、予想以上にスケールの除去
が行われ、酸洗槽８における酸洗条件が大幅に緩和され
ることを見い出した。また、ブラッシング中或いはブラ
ッシング後に高圧水スプレーするとき、鋼帯表面に残留
しているスケール片の除去が一層促進される。熱延鋼帯
を高圧下圧延するとき、基地鋼の展延に追従できないス
ケールには、亀裂，層間剥離等が生じ、基地鋼に対する
密着性が低下する。このような鋼帯をブラッシングする
とき、スケール層に発生している隙間にブラシ毛が入り
込み、鋼帯表面からスケールが除去される。このとき、
砥粒入りのブラシを使用すると、スケールの除去が一層
促進される。ブラッシング後にも残留しているスケール
は、たとえば１０〜５００ｋｇｆ／ｃｍ2 程度の高圧水
を吹き付けることにより、基地鋼を傷付けることなく除
去される。However, the scale-like peeled scale pieces are
Even if it is peeled from the steel strip and has strong adhesion to the surface of the steel material, it may be transferred to the surface of the rolling roll and then pressed or pressed again on the surface of the steel strip. Therefore,
The present inventors have tried a method of brushing the surface of the steel strip after cold rolling to remove the residual scale from the surface of the steel strip and to remove the scale pieces adhering to the surface of the rolling roll. As a result, it was found that the scale was removed more than expected and the pickling conditions in the pickling tank 8 were significantly eased. Further, when the high-pressure water is sprayed during or after the brushing, the removal of the scale pieces remaining on the surface of the steel strip is further promoted. When the hot-rolled steel strip is rolled under high pressure, cracks, delamination, etc. occur in the scale that cannot follow the expansion of the base steel, and the adhesion to the base steel decreases. When brushing such a steel strip, brush bristles enter the gaps generated in the scale layer, and the scale is removed from the surface of the steel strip. At this time,
The removal of scale is further promoted by using a brush containing abrasive grains. The scale remaining after the brushing is removed, for example, by spraying high-pressure water of about 10 to 500 kgf / cm 2 without damaging the base steel.
【００１０】このようにして、ブラッシングにより、大
半のスケールが鋼帯表面から除去されるので、酸洗処理
で取り除くべきスケールは極く僅かなものとなる。その
ため、酸洗負荷が大幅に軽減される。また、ブラッシン
グ中又はブラッシング後のスプレーで使用する高圧水と
して、８０〜９５℃に保持された温水を使用すると、高
圧下冷延に起因する加工熱で昇温した鋼帯を降温させる
ことなく酸洗槽に搬入できる。そのため、酸洗浴の温度
低下が抑制され、一定した酸洗条件下での処理が可能に
なると共に、酸洗浴の温度補償に必要なエネルギーも節
減される。酸洗前の高圧下圧延は、酸洗後に行われる通
常の冷間圧延と同様に鋼材を加工硬化させ、必要な特性
を作り込む。本発明にあっては、この高圧下圧延を通常
の酸洗後圧延に置き換えることにより、酸洗負荷の軽減
と共に、工程の省略化，単純化を図っている。このよう
な置換えが可能になったことは、酸洗前圧延によるディ
スケーリングの際に残留スケールの問題が解消されたこ
とに起因する。In this way, most of the scale is removed from the surface of the steel strip by brushing, so that the scale to be removed by the pickling treatment is extremely small. Therefore, the pickling load is significantly reduced. Moreover, when hot water held at 80 to 95 ° C. is used as the high-pressure water used during spraying during brushing or after brushing, acid is generated without lowering the temperature of the steel strip heated by the processing heat caused by cold rolling under high pressure. Can be carried into the washing tank. Therefore, the temperature drop of the pickling bath is suppressed, the treatment under constant pickling conditions becomes possible, and the energy required for temperature compensation of the pickling bath is also saved. In the high-pressure rolling before pickling, the steel material is work-hardened in the same manner as the ordinary cold rolling performed after pickling, and necessary characteristics are created. In the present invention, the high pressure rolling is replaced with the normal post-pickling rolling to reduce the pickling load and to simplify and simplify the process. The fact that such replacement is possible is due to elimination of the problem of residual scale during descaling by pre-pickling rolling.
【００１１】酸洗前に１０％以上の圧下率で冷間圧延さ
れた鋼帯は、加工硬化しており、硬度は増加するが伸び
が減少している。冷間圧延の圧下率が高いほど、焼鈍時
の再結晶開始温度が低く、また焼鈍後の結晶粒が均一に
なる。結晶粒が粗粒化すると、表面に凹凸のある肌荒れ
が発生し、良好な表面に仕上がらない。しかし、何れに
しても冷間圧延率の圧下率４０％以上での焼鈍後の組織
は、均一で安定した組織となる。したがって、酸洗前の
圧延で、圧下率を４０％以上とすることにより、その後
の焼鈍で良好な組織をもった鋼板が得られる。鋼板の組
織については、圧下率が大きい方が有利である。しか
し、圧下率が大きくなりすぎると、圧延荷重が高くな
り、ロールバイトでの面圧が高く、スケールを基地鋼に
押し込み圧着する場合がある。このような状態では、脱
スケール性が劣り、また酸洗後の鋼板表面にもスケール
起因の肌荒れが発生する。したがって、酸洗前の圧延で
の圧下率の上限は５０％とする。The steel strip cold-rolled at a reduction ratio of 10% or more before pickling has been work-hardened and has increased hardness but decreased elongation. The higher the reduction ratio of cold rolling, the lower the recrystallization start temperature during annealing, and the more uniform the crystal grains after annealing. If the crystal grains become coarse, the surface will be roughened and the surface will not be finished well. However, in any case, the structure after annealing at a cold rolling reduction of 40% or more becomes a uniform and stable structure. Therefore, by setting the rolling reduction to 40% or more in the rolling before pickling, a steel sheet having a good structure can be obtained in the subsequent annealing. With regard to the structure of the steel sheet, it is advantageous that the reduction rate is large. However, if the rolling reduction becomes too large, the rolling load becomes high, the surface pressure at the roll bite becomes high, and the scale may be pressed into the base steel and pressure-bonded. In such a state, the descaling property is inferior, and the surface of the steel sheet after pickling is roughened due to scale. Therefore, the upper limit of the reduction rate in rolling before pickling is 50%.
【００１２】[0012]
【実施例】板厚３．２ｍｍの熱延鋼帯を、図１に示すデ
ィスケーリングラインで酸洗に先立って圧下率５〜５０
％で冷間圧延した。熱延鋼帯としては、表１に示す成分
・組成を持ち、表面に平均厚み１０μｍの熱延スケール
が付着したままの熱延鋼帯を使用した。また、圧延中に
は、ロール周面に対向させたポリッシャーでワークロー
ル表面に転写されたスケール片を除去した。Example A hot-rolled steel strip having a plate thickness of 3.2 mm was drawn at a descaling line shown in FIG.
Cold rolled in%. As the hot-rolled steel strip, a hot-rolled steel strip having the components and compositions shown in Table 1 and having a hot-rolled scale having an average thickness of 10 μm attached to the surface was used. Further, during rolling, scale pieces transferred to the work roll surface were removed by a polisher facing the peripheral surface of the roll.
【００１３】 [0013]
【００１４】圧延によりディスケーリングした鋼帯を、
塩酸系の酸液を９０℃に保持した酸洗槽に搬入し、酸液
に各試験片を５秒間浸漬した。この酸洗条件は、通常の
酸洗条件とほぼ同じものである。しかし、酸洗槽に持ち
込まれるスケールが極めて少なくなっているため、酸洗
された鋼帯は、従来の酸洗結果を凌駕する表面性状をも
っていた。冷間圧延後、酸洗された鋼帯に対して熱処理
を施した。熱処理には、７５０℃まで加熱した後、６８
秒間均熱保持する条件を採用した。熱処理された鋼帯の
金属組織は、粗粒化しておらず、均一で且つ適正な粒度
をもっていた。また、鋼帯の機械試験値も冷延鋼板とし
て十分なものが得られた。A steel strip descaled by rolling is
The hydrochloric acid-based acid solution was carried into a pickling tank held at 90 ° C., and each test piece was immersed in the acid solution for 5 seconds. The pickling conditions are almost the same as the normal pickling conditions. However, since the scale brought into the pickling tank is extremely small, the pickled steel strip has a surface texture that surpasses conventional pickling results. After cold rolling, the pickled steel strip was heat-treated. For heat treatment, after heating to 750 ° C, 68
The condition of maintaining uniform heat for 2 seconds was adopted. The metal structure of the heat-treated steel strip was not coarse-grained and had a uniform and proper grain size. In addition, the mechanical test values of the steel strip were sufficient as a cold rolled steel sheet.
【００１５】たとえば、伸びについて評価すると、従来
法で製造された冷延鋼板と同レベルにある。具体的に
は、鋼種Ａ及び鋼種Ｂの伸びは、圧下率に応じてそれぞ
れ図３及び図４に示すように変化した。すなわち、一定
焼鈍温度における圧下率と伸びとの関係は、鋼種Ａでは
圧下率１０％以下，鋼種Ｂでは圧下率２０％以下の範囲
では、圧下率の上昇に従って得られる鋼板の伸びが低下
した。一方、鋼種Ａでは圧下率１０％以上，鋼種Ｂでは
圧下率２０％以上では、圧下率の上昇に応じて伸びも高
くなる。しかし、４０％未満の圧下率では、金属組織が
粗粒化することもある。したがって、酸洗前圧延後に酸
洗のみを施すことにより必要な特性を備えた冷延鋼帯を
得るためには、酸洗前圧延の圧下率を４０％以上にする
ことが必要である。圧下率４０％以上の領域では、圧下
率の上昇に伴って伸びが高くなり、金属組織が粗粒化す
ることもなく安定する。For example, when the elongation is evaluated, it is at the same level as the cold-rolled steel sheet manufactured by the conventional method. Specifically, the elongations of the steel types A and B changed as shown in FIGS. 3 and 4 depending on the rolling reduction. That is, regarding the relationship between the rolling reduction and the elongation at a constant annealing temperature, the elongation of the steel sheet obtained decreased as the rolling reduction increased in the range of the rolling reduction of 10% or less for the steel type A and 20% or less of the rolling reduction for the steel type B. On the other hand, when the rolling reduction is 10% or more for steel type A and the rolling reduction is 20% or more for steel type B, the elongation increases as the rolling reduction increases. However, if the rolling reduction is less than 40%, the metal structure may become coarse. Therefore, in order to obtain the cold-rolled steel strip having the required characteristics by performing only pickling after the pre-pickling rolling, it is necessary to set the reduction ratio of the pre-pickling rolling to 40% or more. In the region where the rolling reduction is 40% or more, the elongation increases as the rolling reduction increases, and the metal structure stabilizes without coarsening.
【００１６】[0016]
【発明の効果】以上に説明したように、本発明において
は、ディスケーリング機能をもつ酸洗前の高圧下冷間圧
延によって鋼帯を加工硬化させ、必要な特性を作り込ん
でいる。そのため、酸洗された鋼帯を熱処理するだけ
で、表面処理鋼用原板等の用途に使用できる冷延鋼帯が
得られる。また、冷間圧延を施す場合にあっても、軽度
の圧下率で製品形状を出すことができるため、工程の省
略，単純化が可能になる。しかも、酸洗負荷が減少し、
酸洗時間の短縮，酸洗設備の小規模化や低濃度酸液の使
用等が可能となり、また酸洗に起因する欠陥が素材に持
ち込まれることも抑制される。As described above, according to the present invention, the steel strip is work-hardened by cold rolling under a high pressure before pickling having a descaling function, and necessary characteristics are created. Therefore, only by heat-treating the pickled steel strip, a cold-rolled steel strip that can be used for applications such as a surface-treated steel plate can be obtained. Further, even when cold rolling is performed, the product shape can be obtained with a slight reduction, so that the steps can be omitted and simplified. Moreover, the pickling load is reduced,
The pickling time can be shortened, the pickling equipment can be downsized, and low-concentration acid solutions can be used. In addition, defects caused by pickling can be prevented from being introduced into the material.
【図１】 本発明に従った熱延鋼帯のディスケーリング
ライン1 is a descaling line for hot rolled steel strip according to the present invention.
【図２】 熱延鋼帯表面に形成されているスケールの層
構成FIG. 2 Layer structure of scales formed on the surface of hot-rolled steel strip
【図３】 鋼種Ａを高圧下圧延したときの圧下率と伸び
との関係[Fig. 3] Relationship between rolling reduction and elongation when steel type A is rolled under high pressure
【図４】 鋼種Ｂを高圧下圧延したときの圧下率と伸び
との関係[Fig. 4] Relationship between rolling reduction and elongation when steel type B is rolled under high pressure
１：スケールが付着している熱延鋼帯 ２：ペイオフ
リール ３：ブライドルロール ４：冷間圧延機
５：ブラシ ６：スプレー装置 ７：スプレーノ
ズル ８：酸洗槽 ９：巻取りリール1: Hot-rolled steel strip with scale attached 2: Payoff reel 3: Bridle roll 4: Cold rolling mill
5: Brush 6: Spray device 7: Spray nozzle 8: Pickling tank 9: Take-up reel
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.7 識別記号 ＦＩ Ｃ２３Ｇ 1/08 Ｃ２３Ｇ 1/08 3/02 3/02 (72)発明者 早川 淳也 大阪府堺市石津西町５番地 日新製鋼株 式会社 堺製造所内 (56)参考文献 特開 昭55−27408（ＪＰ，Ａ) 特開 昭60−145216（ＪＰ，Ａ) 特公 昭63−41647（ＪＰ，Ｂ１) (58)調査した分野(Int.Cl.7，ＤＢ名) B21B 45/04 B21B 45/06 B21B 45/08 ─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. 7 Identification code FI C23G 1/08 C23G 1/08 3/02 3/02 (72) Inventor Junya Hayakawa 5 Niishin Steel, Ishizu Nishimachi, Sakai City, Osaka Prefecture Stock company Sakai Factory (56) References JP 55-27408 (JP, A) JP 60-145216 (JP, A) JP 63-41647 (JP, B1) (58) Fields investigated (Int.Cl. 7 , DB name) B21B 45/04 B21B 45/06 B21B 45/08
Claims (2)
鋼帯を４０〜５０％の圧下率で冷間圧延し、鋼帯表面か
ら剥離したスケール片をブラッシングで除去した後、鋼
帯を酸洗槽に搬入して残留スケールを酸洗除去し、次い
で焼鈍することを特徴とする冷延鋼帯の製造方法。1. A hot-rolled steel strip having a hot-rolled scale adhered to its surface is cold-rolled at a reduction rate of 40 to 50% , and scale pieces peeled from the surface of the steel strip are removed by brushing. Is carried into a pickling tank to remove residual scale by pickling and then annealed, and a method for producing a cold rolled steel strip.
との間でスプレー処理する請求項１記載の冷延鋼帯の製
造方法。2. During brushing or brushing and pickling
The method for producing a cold-rolled steel strip according to claim 1 , wherein spray treatment is performed between the cold-rolled steel strip and the cold-rolled steel strip.
Priority Applications (8)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP26922896A JP3371061B2 (en) | 1995-10-11 | 1996-09-19 | Method of manufacturing cold rolled steel strip by rolling before pickling |
| PCT/JP1996/002903 WO1997013596A1 (en) | 1995-10-11 | 1996-10-07 | Method of descaling steel sheet in coil through high draft rolling |
| CN96191202A CN1079303C (en) | 1995-10-11 | 1996-10-07 | Method of descaling steel sheet in coil through high draft rolling |
| KR1019970703903A KR100229819B1 (en) | 1995-10-11 | 1996-10-07 | Method of descaling steel sheet in coil through high draft rolling |
| DE69625997T DE69625997T2 (en) | 1995-10-11 | 1996-10-07 | METHOD FOR DESCALING STEEL COILS BY ROLLING WITH HIGH ROLLING PRESSURE |
| US08/849,215 US6210501B1 (en) | 1995-10-11 | 1996-10-07 | Heavy-duty cold-rolling for mechanically descaling a hot-rolled steel strip before pickling |
| EP96932826A EP0796675B1 (en) | 1995-10-11 | 1996-10-07 | Method of descaling steel sheet in coil by high draft rolling |
| CN01124090.3A CN1184026C (en) | 1995-10-11 | 1996-10-07 | Device for removing oxide layer on surface of hot steel rolling belt |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7-290317 | 1995-10-11 | ||
| JP29031795 | 1995-10-11 | ||
| JP26922896A JP3371061B2 (en) | 1995-10-11 | 1996-09-19 | Method of manufacturing cold rolled steel strip by rolling before pickling |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH09164418A JPH09164418A (en) | 1997-06-24 |
| JP3371061B2 true JP3371061B2 (en) | 2003-01-27 |
Family
ID=26548676
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP26922896A Expired - Lifetime JP3371061B2 (en) | 1995-10-11 | 1996-09-19 | Method of manufacturing cold rolled steel strip by rolling before pickling |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3371061B2 (en) |
-
1996
- 1996-09-19 JP JP26922896A patent/JP3371061B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH09164418A (en) | 1997-06-24 |
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