WO2015019409A1 - Process for producing cold-rolled low-carbon-steel strip - Google Patents

Process for producing cold-rolled low-carbon-steel strip Download PDF

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Publication number
WO2015019409A1
WO2015019409A1 PCT/JP2013/071193 JP2013071193W WO2015019409A1 WO 2015019409 A1 WO2015019409 A1 WO 2015019409A1 JP 2013071193 W JP2013071193 W JP 2013071193W WO 2015019409 A1 WO2015019409 A1 WO 2015019409A1
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cold
steel strip
rolled
rolling
roll
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PCT/JP2013/071193
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French (fr)
Japanese (ja)
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洋一 谷村
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日新製鋼株式会社
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Priority to CN201380077756.XA priority Critical patent/CN105377458B/en
Priority to PCT/JP2013/071193 priority patent/WO2015019409A1/en
Publication of WO2015019409A1 publication Critical patent/WO2015019409A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B1/00—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations
    • B21B1/22—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling plates, strips, bands or sheets of indefinite length
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B1/00—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations
    • B21B1/22—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling plates, strips, bands or sheets of indefinite length
    • B21B2001/228—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling plates, strips, bands or sheets of indefinite length skin pass rolling or temper rolling
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B2267/00—Roll parameters
    • B21B2267/10—Roughness of roll surface
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B27/00—Rolls, roll alloys or roll fabrication; Lubricating, cooling or heating rolls while in use
    • B21B27/02—Shape or construction of rolls
    • B21B27/021—Rolls for sheets or strips

Definitions

  • the present invention relates to a method for producing a low carbon steel cold-rolled steel strip excellent in surface smoothness.
  • a low carbon steel cold-rolled steel strip excellent in surface smoothness is manufactured by temper rolling a cold-rolled steel strip that has been cold-rolled to a predetermined thickness.
  • temper rolling a bright roll is used as a work roll, and the smooth surface of the bright roll is transferred to a material to be rolled (cold rolled steel strip), so that the surface of the rolled material is finished in a smooth state.
  • temper rolling two methods of wet temper rolling and dry temper rolling are widely known.
  • temper rolling oil lubricating oil
  • temper rolling oil lubricating oil
  • indentation flaws generated on the material to be rolled are prevented. . Note that the indentation occurs when foreign matter is caught between the work roll and the material to be rolled and the foreign matter is pushed into the material to be rolled.
  • dry temper rolling is temper rolling in a state where the material to be rolled and the work roll are almost dry without supplying temper rolling oil (lubricating oil) to the surface of the material to be rolled and the work roll. is there.
  • temper rolling oil lubricating oil
  • the smooth surface of the bright roll is efficiently transferred to the material to be rolled.
  • since there is no cleaning action of temper rolling oil foreign matter is likely to adhere to the material to be rolled and the work roll, and indentation wrinkles are likely to occur.
  • the manufacturing method of the low carbon steel cold-rolled steel strip currently disclosed by patent document 1 degrease-cleans the cold-rolled steel strip which consists of low carbon steel, Then, this cold-rolled steel strip is dry-temper-rolled with a bright roll. Is.
  • this method of manufacturing a low-carbon steel cold-rolled steel strip after the fats and oils and foreign matter adhering to the surface of the material to be rolled (cold-rolled steel strip) are removed by the degreasing cleaning treatment, Since the dry temper rolling is performed, the material to be rolled can be temper-rolled with less adhesion of foreign matters, and a product steel strip excellent in surface smoothness can be produced.
  • the degreasing cleaning treatment can remove foreign matter adhering to the surface of the cold-rolled steel strip to some extent, but the degreasing cleaning is performed. It is difficult to remove foreign matter adhering to the material to be rolled after processing and foreign matter adhering to the work roll of the dry temper rolling mill. Therefore, indentation flaws may sometimes occur on the surface of the product steel strip after dry temper rolling. In order to prevent foreign matter from adhering to the surface of the work roll of the dry temper rolling mill, it is possible to ensure that foreign matter adheres to the surface of the work roll even if the dry temper rolling mill and its surroundings are thoroughly cleaned. It is difficult to prevent.
  • wet temper rolling is adopted instead of dry temper rolling, foreign matter adhering to the surface of the material to be rolled and the work roll can be completely removed by the cleaning action of the temper rolling oil, and indentation flaws are generated. Can be prevented.
  • the transfer efficiency of the smooth surface of the bright roll with respect to the material to be rolled is reduced, and the surface smoothness of the product steel strip is required to be constant (for example, the surface roughness Ra). May be less than 0.3 ⁇ m).
  • the present invention was devised in view of the above-mentioned problems, and when wet temper rolling is used to prevent the occurrence of indentation flaws in the cold-rolled steel strip, and when dry tempering pressure is adopted. It aims at providing the manufacturing method of the low carbon steel cold-rolled steel strip which can manufacture the cold-rolled steel strip which has surface smoothness comparable as the cold-rolled steel strip manufactured.
  • the method for producing a low-carbon steel cold-rolled steel strip according to the present invention is based on the assumption that the steel strip made of low-carbon steel is cold-rolled and then subjected to wet temper rolling using a bright roll. Is characterized in that at least one pass is carried out using a dull roll and then the final pass is carried out using a smooth roll.
  • the surface roughness Ra of the cold-rolled steel strip subjected to the wet temper rolling is 0.3 ⁇ m or less.
  • the smooth roll has a surface roughness Ra of 0.1 ⁇ m to 0.3 ⁇ m.
  • the surface roughness Ra of the dull roll is 1.0 ⁇ m to 1.8 ⁇ m.
  • the method for producing a low-carbon steel cold-rolled steel strip of the present invention it is possible to prevent the occurrence of indentation or the like in the product steel strip without reducing the surface smoothness of the product steel strip.
  • This low carbon steel cold-rolled steel strip manufacturing method uses a low-carbon steel slab prepared in a predetermined steel composition as a raw material, and cold-rolls the steel strip obtained through a hot rolling process, pickling process, etc. After that, wet temper rolling is performed.
  • wet temper rolling it is possible to omit the degreasing cleaning process for removing the cold rolling oil or the like adhering to the material to be rolled after the cold rolling.
  • work hardening due to cold rolling is unlikely to occur in low carbon steel, it is possible to omit the step of annealing the material to be rolled after cold rolling and before wet temper rolling.
  • the steel material type of the low-carbon steel cold-rolled steel strip is, for example, a low-carbon steel having a C content of 0.12% by mass or less.
  • a typical example of this low carbon steel is “SPCC” described in the “Reference” column of JIS G 3141 “Cold rolled steel sheet and steel strip”. This SPCC has a C content of 0.12% by mass or less, an Mn content of 0.50% by mass or less, a P content of 0.040% by mass or less, and an S content of 0.045% by mass or less.
  • the balance consists of Fe and inevitable impurities.
  • the cold rolling mill that performs the cold rolling for example, a lever type cold rolling mill capable of reversing the rolling direction can be used.
  • a dull roll is used in the first pass.
  • the dull roll is continuously used unless it is the final pass.
  • the dull roll preferably has a surface roughness Ra of 1.0 ⁇ m to 1.8 ⁇ m, and the smooth roll has a surface roughness Ra of 0.1 ⁇ m to 0.3 ⁇ m. Is desirable.
  • the number of passes is not particularly limited.
  • the surface roughness Ra is a center line average roughness defined in JIS B 0601.
  • the cold rolling reduction ratio is appropriately determined according to the use of the steel strip, and is preferably about 50% to 70%, for example.
  • a bright roll is used as a work roll of a wet temper rolling mill, and rolling is performed while supplying temper rolling oil (lubricating oil) to both the work roll and the material to be rolled.
  • the elongation ( ⁇ ) of the steel strip in wet temper rolling needs to be controlled in the range of 0.2 to 1.5%.
  • the width load corresponding to the elongation ( ⁇ ) is about 0.3 to 0.7 Ton / mm.
  • the reason why the elongation ( ⁇ ) is limited to the above range (0.2 to 1.5%) is that the temper rolling with a lower elongation than this has a weak transfer effect on the roll surface and the smoothness of the surface of the product steel strip. This is because temper rolling exceeding the above range causes a significant decrease in the ductility of the product steel strip, making it difficult to ensure good press workability.
  • the preferred elongation ( ⁇ ) is about 0.4 to 1.0%, and most preferably 0.6 to 0.8%.
  • the applicant of the present application has previously performed cold rolling using a smooth roll having a surface roughness Ra of 0.4 ⁇ m to 0.6 ⁇ m in all passes as a work roll of a cold rolling mill. After degreasing and cleaning, dry temper rolling was performed to produce a product steel strip (low carbon steel cold-rolled steel strip) that satisfies a certain specification (for example, surface roughness Ra is 0.3 ⁇ m or less).
  • a product steel strip low carbon steel cold-rolled steel strip
  • a certain specification for example, surface roughness Ra is 0.3 ⁇ m or less.
  • the inventor of the present application adopted a wet temper rolling as a temper rolling, and on the premise that generation of indentation flaws is completely prevented, It came to solve it paying attention to the surface roughness of the work roll used in rolling. That is, as described above, in cold rolling, the first pass uses a dull roll, and the second pass and beyond, except when the final pass is used, the dull roll is used continuously, and the smooth pass is used in the final pass. It was found that the product steel strip after wet temper rolling can satisfy the above-mentioned certain specifications.
  • the reason why the product steel strip can satisfy the above-mentioned specific specifications by changing the surface roughness of the work roll of the cold rolling mill is considered to be related to the formation of oil pits.
  • cooling and lubrication of the material to be rolled and the work roll are performed while supplying rolling oil to the material to be rolled and the work roll.
  • Ra surface roughness
  • the rolling oil enters the irregularities on the surface of the dull roll and the surface functions as an oil pit when the dull roll is used. Oil pits are hardly formed on the rolled material. Then, in the final pass, by using a smooth roll having a surface roughness Ra of 0.1 ⁇ m to 0.3 ⁇ m (having a surface roughness much smaller than the previously used smooth roll), the coated film after cold rolling is used.
  • the surface roughness of the rolled material is much smaller than before, and even if the transfer efficiency of the bright roll to the material to be rolled is reduced in wet temper rolling, it compensates for the decrease in the transfer efficiency, and after temper rolling
  • the surface roughness of the product steel strip can be secured sufficiently. That is, it becomes possible to satisfy the certain specification (surface roughness Ra is 0.3 ⁇ m or less).
  • the wet roll is adopted as the temper rolling performed after the cold rolling, and the work roll of the temper rolling mill
  • the tempered rolling oil is supplied to both the rolled material and the rolled material, and the foreign matter adhering to the work roll and the surface of the rolled material is washed away by the cleaning action of the tempered rolling oil, so that the occurrence of indentation flaws in the rolled material is prevented. can do.
  • the first pass of cold rolling uses a dull roll having a surface roughness Ra of 1.0 ⁇ m to 1.8 ⁇ m, and the second pass and thereafter continue to use the same dull roll except for the final pass.
  • a low-carbon steel slab is used as a raw material, and cold rolling is performed on a material to be rolled obtained through hot rolling and pickling treatment (descaling treatment) of a hot-rolled steel sheet.
  • cold rolling a dull roll having a surface roughness Ra of 1.0 ⁇ m to 1.8 ⁇ m is used as a work roll in the first to fourth passes, and the surface roughness Ra is 0.1 ⁇ m to 0.3 ⁇ m in the fifth pass as the final pass.
  • the smooth roll is used as a work roll.
  • a product steel strip (low-carbon steel cold-rolled steel strip) having a surface roughness adjusted by wet temper rolling was obtained without degreasing and washing the cold-rolled steel strip obtained in this way.
  • This steel strip is a plate material equivalent to SPCC-1B (JIS G3141) (tempering classification: hard, surface finishing classification: bright finish).
  • a low-carbon steel slab is used as a raw material, and the rolled material obtained through hot rolling and pickling treatment of a hot-rolled steel plate is 1-5.
  • Cold rolling is performed using a smooth roll with a surface roughness Ra of 0.4 ⁇ m to 0.6 ⁇ m as a work roll up to the pass, and the resulting cold-rolled steel strip is degreased and washed, and then dry tempered
  • a product steel (low-carbon steel cold-rolled steel strip) strip whose surface roughness was adjusted by rolling was also obtained.
  • This steel strip is also a plate material equivalent to SPCC-1B (JIS G3141) (tempering classification: hard, surface finishing classification: bright finish).
  • the steel composition, hot rolling conditions, and cold rolling conditions in the manufacturing method according to the embodiment of the present invention and the conventional manufacturing method are as follows (1) to (3). That is, (1) Steel composition has a C content of 0.02 to 0.06 mass%, an Mn content of 0.4 to 0.48 mass%, a P content of 0.02 mass%, and an S content. Is 0.01% by mass. (2)
  • the hot rolling conditions are a hot rolling finishing temperature of 875 to 935 ° C. and a winding temperature of 535 to 635 ° C. (3)
  • the cold rolling conditions are a rolling reduction of 52.6% and a cold-rolled sheet thickness of 1.61 mm.
  • a bright roll having a smooth surface subjected to a wet grinding process (using a grinding wheel of grain size # 320) was used as a work roll.
  • “ND-10 Kai” manufactured by Daido Chemical Co., Ltd.
  • the steel strip elongation was 0.6 to 0.7%.
  • FIG. 1 shows the measurement result of the surface roughness of the product steel strip obtained by the manufacturing method according to the embodiment of the present invention, and the measurement result of the surface roughness of the product steel strip obtained by the previous manufacturing method of FIG. Indicates.
  • the product steel strip obtained by the manufacturing method according to the embodiment of the present invention has an N number (production number) of 21 and an average value of the surface roughness Ra of 0.148 (0.154).
  • the standard deviation was 0.011 (0.011), the maximum value was 0.169 (0.171), and the minimum value was 0.125 (0.132).
  • the value outside () shows the surface (namely, upper surface) of a steel strip
  • the value inside () shows the back surface (namely, lower surface) of a steel strip. No indentation flaws were found in the product steel strip obtained by this manufacturing method.
  • the product steel strip obtained by the conventional manufacturing method has an N number (production number) of 304 (304), an average value of the surface roughness Ra of 0.151 (0.169), and a standard deviation.
  • the maximum value was 0.035 (0.033), the maximum value was 0.284 (0.292), and the minimum value was 0.078 (0.075).
  • the present invention can be applied to, for example, a production line for producing a low-carbon steel cold-rolled steel strip excellent in surface smoothness, and the produced low-carbon steel cold-rolled steel strip includes mechanical parts, electric / electronic It is suitably used for equipment parts, automobile parts and the like.

Abstract

The purpose of the present invention is to produce a cold-rolled steel strip having no indentation flaws by adopting wet temper rolling, the cold-rolled steel strip being comparable in surface smoothness to the cold-rolled steel strip produced in the case of adopting dry temper rolling. A steel strip constituted of low-carbon steel is cold-rolled, and then subjected to wet temper rolling using bright rolls to thereby produce a cold-rolled low-carbon-steel strip that has a surface roughness Ra of 0.3 μm or less. The cold rolling is performed in such a manner that at least one pass is performed using dull rolls having a surface roughness Ra of 1.0-1.8 μm and thereafter the final pass is performed using smooth rolls having a surface roughness Ra of 0.1-0.3 μm.

Description

低炭素鋼冷延鋼帯の製造方法Low carbon steel cold rolled steel strip manufacturing method
　本発明は、表面平滑性に優れた低炭素鋼冷延鋼帯の製造方法に関する。 The present invention relates to a method for producing a low carbon steel cold-rolled steel strip excellent in surface smoothness.
　一般に、表面平滑性に優れた低炭素鋼冷延鋼帯は、所定の板厚に冷間圧延された冷延鋼帯が調質圧延されることによって製造される。調質圧延では、ワークロールとしてブライトロールが用いられ、ブライトロールの平滑面が被圧延材（冷延鋼帯）に転写されることで当該圧延材の表面が平滑な状態に仕上げられる。 Generally, a low carbon steel cold-rolled steel strip excellent in surface smoothness is manufactured by temper rolling a cold-rolled steel strip that has been cold-rolled to a predetermined thickness. In temper rolling, a bright roll is used as a work roll, and the smooth surface of the bright roll is transferred to a material to be rolled (cold rolled steel strip), so that the surface of the rolled material is finished in a smooth state.
　調質圧延としては、ウエット調質圧延およびドライ調質圧延の２方式が広く知られている。ウエット調質圧延は、被圧延材およびワークロールの双方に調質圧延油（潤滑油）を供給しながら調質圧延を行うものである。この調質圧延油による洗浄作用によって被圧延材の表面の油脂類（冷間圧延時の圧延油等）や鉄粉、その他の異物が洗い流される結果、被圧延材に生じる押し込み疵が防止される。なお、押し込み疵は、ワークロールと被圧延材との間に異物が噛み込み、当該異物が被圧延材に押し込まれることにより発生する。しかし、ウエット調質圧延によれば、ワークロールと被圧延材との間に調質圧延油が介在することから、被圧延材に対するブライトロールの平滑面の転写効率が低下し、製品鋼帯の表面粗度が大きくなってしまうという問題がある。 As temper rolling, two methods of wet temper rolling and dry temper rolling are widely known. In the wet temper rolling, temper rolling is performed while supplying temper rolling oil (lubricating oil) to both the material to be rolled and the work roll. As a result of washing of the surface of the material to be rolled (such as rolling oil during cold rolling), iron powder, and other foreign matters by the cleaning action of the tempered rolling oil, indentation flaws generated on the material to be rolled are prevented. . Note that the indentation occurs when foreign matter is caught between the work roll and the material to be rolled and the foreign matter is pushed into the material to be rolled. However, according to wet temper rolling, since the temper rolling oil is interposed between the work roll and the material to be rolled, the transfer efficiency of the smooth surface of the bright roll to the material to be rolled is lowered, and the product steel strip There is a problem that the surface roughness becomes large.
　一方、ドライ調質圧延は、調質圧延油（潤滑油）を被圧延材およびワークロールの表面に供給することなく、被圧延材およびワークロールがほぼ乾燥した状態で調質圧延を行うものである。このため、調質圧延中は、ワークロールが油膜を介することなく被圧延材に直接接触するため、ブライトロールの平滑面が効率的に被圧延材に転写されることとなる。しかし、ドライ調質圧延によれば、調質圧延油の洗浄作用がないことから、異物が被圧延材やワークロールに付着し易く、押し込み疵が発生し易くなる。 On the other hand, dry temper rolling is temper rolling in a state where the material to be rolled and the work roll are almost dry without supplying temper rolling oil (lubricating oil) to the surface of the material to be rolled and the work roll. is there. For this reason, during the temper rolling, since the work roll is in direct contact with the material to be rolled without passing through the oil film, the smooth surface of the bright roll is efficiently transferred to the material to be rolled. However, according to dry temper rolling, since there is no cleaning action of temper rolling oil, foreign matter is likely to adhere to the material to be rolled and the work roll, and indentation wrinkles are likely to occur.
　特許文献１に開示されている低炭素鋼冷延鋼帯の製造方法は、低炭素鋼からなる冷延鋼帯を脱脂洗浄処理した後、この冷延鋼帯をブライトロールによりドライ調質圧延するものである。この低炭素鋼冷延鋼帯の製造方法によれば、脱脂洗浄処理により被圧延材（冷延鋼帯）の表面に付着している油脂類および異物が除去された後に、当該被圧延材がドライ調質圧延されることから、異物の付着が少ない状態で被圧延材を調質圧延することができ、表面平滑性に優れた製品鋼帯を製造することができる。 The manufacturing method of the low carbon steel cold-rolled steel strip currently disclosed by patent document 1 degrease-cleans the cold-rolled steel strip which consists of low carbon steel, Then, this cold-rolled steel strip is dry-temper-rolled with a bright roll. Is. According to this method of manufacturing a low-carbon steel cold-rolled steel strip, after the fats and oils and foreign matter adhering to the surface of the material to be rolled (cold-rolled steel strip) are removed by the degreasing cleaning treatment, Since the dry temper rolling is performed, the material to be rolled can be temper-rolled with less adhesion of foreign matters, and a product steel strip excellent in surface smoothness can be produced.
特開２００７－１３０６７９号公報JP 2007-130679 A
　ところが、特許文献１に開示されている低炭素鋼冷延鋼帯の製造方法では、脱脂洗浄処理により、冷延鋼帯の表面に付着している異物をある程度除去することはできるものの、脱脂洗浄処理後に被圧延材に付着した異物や、ドライ調質圧延機のワークロールに付着した異物を除去することは困難である。そのため、ドライ調質圧延後の製品鋼帯の表面に時々押し込み疵が発生することがある。ドライ調質圧延機のワークロールの表面に異物が付着しないように、ドライ調質圧延機およびその周囲の清掃作業を徹底して行うなどしてもワークロールの表面に異物が付着することを完全に防止することは難しい。 However, in the method for producing a low-carbon steel cold-rolled steel strip disclosed in Patent Document 1, the degreasing cleaning treatment can remove foreign matter adhering to the surface of the cold-rolled steel strip to some extent, but the degreasing cleaning is performed. It is difficult to remove foreign matter adhering to the material to be rolled after processing and foreign matter adhering to the work roll of the dry temper rolling mill. Therefore, indentation flaws may sometimes occur on the surface of the product steel strip after dry temper rolling. In order to prevent foreign matter from adhering to the surface of the work roll of the dry temper rolling mill, it is possible to ensure that foreign matter adheres to the surface of the work roll even if the dry temper rolling mill and its surroundings are thoroughly cleaned. It is difficult to prevent.
　ドライ調質圧延の代わりにウエット調質圧延を採用すれば、調質圧延油の洗浄作用によって被圧延材やワークロールの表面に付着する異物を完全に除去することができ、押し込み疵の発生を防止することができる。しかし、既述したように、ウエット調質圧延によれば、被圧延材に対するブライトロールの平滑面の転写効率が低下し、製品鋼帯の表面平滑性が一定の要求（例えば、表面粗度Ｒａが０．３μｍ以下であること）を満たすことが難しくなる場合がある。 If wet temper rolling is adopted instead of dry temper rolling, foreign matter adhering to the surface of the material to be rolled and the work roll can be completely removed by the cleaning action of the temper rolling oil, and indentation flaws are generated. Can be prevented. However, as described above, according to the wet temper rolling, the transfer efficiency of the smooth surface of the bright roll with respect to the material to be rolled is reduced, and the surface smoothness of the product steel strip is required to be constant (for example, the surface roughness Ra). May be less than 0.3 μm).
　本発明は、既述の問題に鑑みて創案されたものであり、ウエット調質圧延を採用することにより冷延鋼帯における押し込み疵の発生を防止するとともに、ドライ調質圧を採用した場合に製造される冷延鋼帯と同程度の表面平滑性を有する冷延鋼帯を製造することができる、低炭素鋼冷延鋼帯の製造方法を提供することを目的とする。 The present invention was devised in view of the above-mentioned problems, and when wet temper rolling is used to prevent the occurrence of indentation flaws in the cold-rolled steel strip, and when dry tempering pressure is adopted. It aims at providing the manufacturing method of the low carbon steel cold-rolled steel strip which can manufacture the cold-rolled steel strip which has surface smoothness comparable as the cold-rolled steel strip manufactured.
　本発明の低炭素鋼冷延鋼帯の製造方法は、低炭素鋼からなる鋼帯を冷間圧延した後、ブライトロールを用いてウエット調質圧延を行うものを前提としており、前記冷間圧延は、少なくとも１パスをダルロールを用いて実施した後、最終パスをスムースロールを用いて実施するものである、ことを特徴とするものである。 The method for producing a low-carbon steel cold-rolled steel strip according to the present invention is based on the assumption that the steel strip made of low-carbon steel is cold-rolled and then subjected to wet temper rolling using a bright roll. Is characterized in that at least one pass is carried out using a dull roll and then the final pass is carried out using a smooth roll.
　かかる低炭素鋼冷延鋼帯の製造方法によれば、ウエット調質圧延を採用したことにより、調質圧延油の洗浄作用によってワークロールや被圧延材の表面に付着した異物が洗浄除去されるので被圧延材（冷延鋼帯）における押し込み疵の発生を防止することができる。また、ウエット調質圧延前の冷間圧延において、ダルロールを用いた冷間圧延を行うとき、ダルロールの表面がオイルピットとして機能し、被圧延材にオイルピットが形成され難くなる。そして、スムースロールを用いた冷間圧延が最終パスで行われることで、被圧延材の表面平滑性が高められる。この最終パスで用いるスムースロールとして表面粗度が十分に小さなものを用いることで、ウエット調質圧延において被圧延材に対するブライトロールの転写効率が低くなっても、その転写効率の低下分を補って、調質圧延後の製品鋼帯の表面粗度を十分に平滑にすることが可能である。 According to such a method for producing a low-carbon steel cold-rolled steel strip, by adopting wet temper rolling, foreign matter adhering to the surface of the work roll and the material to be rolled is washed away by the cleaning action of the temper rolling oil. Therefore, generation | occurrence | production of the indentation flaw in a to-be-rolled material (cold rolled steel strip) can be prevented. Further, in cold rolling before wet temper rolling, when performing cold rolling using a dull roll, the surface of the dull roll functions as an oil pit, and it is difficult to form an oil pit on the material to be rolled. And the surface smoothness of a to-be-rolled material is improved because the cold rolling using a smooth roll is performed by the last pass. By using a smooth roll with a sufficiently small surface roughness in this final pass, even if the transfer efficiency of the bright roll to the material to be rolled becomes low in wet temper rolling, the decrease in the transfer efficiency is compensated. It is possible to sufficiently smooth the surface roughness of the product steel strip after temper rolling.
　好ましくは、前記ウエット調質圧延を行った冷延鋼帯の表面粗度Ｒａは０．３μｍ以下である。 Preferably, the surface roughness Ra of the cold-rolled steel strip subjected to the wet temper rolling is 0.3 μm or less.
　好ましくは、前記スムースロールの表面粗度Ｒａは０．１μｍ～０．３μｍである。 Preferably, the smooth roll has a surface roughness Ra of 0.1 μm to 0.3 μm.
　好ましくは、前記ダルロールの表面粗度Ｒａは１．０μｍ～１．８μｍである。 Preferably, the surface roughness Ra of the dull roll is 1.0 μm to 1.8 μm.
　本発明の低炭素鋼冷延鋼帯の製造方法によれば、製品鋼帯の表面平滑性を低下させることなく、製品鋼帯における押し込み疵等の発生を防止することが可能である。 According to the method for producing a low-carbon steel cold-rolled steel strip of the present invention, it is possible to prevent the occurrence of indentation or the like in the product steel strip without reducing the surface smoothness of the product steel strip.
本発明の実施例に係る低炭素鋼冷延鋼帯の製造方法により得られた製品鋼帯の表面粗度の測定結果を示す表および棒グラフである。グラフの横軸は製品鋼帯の表面粗度を示し、グラフの縦軸はＮ数（製造個数）を示す。It is a table | surface and a bar graph which show the measurement result of the surface roughness of the product steel strip obtained by the manufacturing method of the low carbon steel cold-rolled steel strip which concerns on the Example of this invention. The horizontal axis of the graph indicates the surface roughness of the product steel strip, and the vertical axis of the graph indicates the N number (production number). 従前の低炭素鋼冷延鋼帯の製造方法により得られた製品鋼帯の表面粗度の測定結果を示す表および棒グラフである。グラフの横軸は製品鋼帯の表面粗度を示し、グラフの縦軸はＮ数（製造個数）を示す。It is a table | surface and a bar graph which show the measurement result of the surface roughness of the product steel strip obtained by the manufacturing method of the conventional low carbon steel cold-rolled steel strip. The horizontal axis of the graph indicates the surface roughness of the product steel strip, and the vertical axis of the graph indicates the N number (production number).
　以下、本発明の実施の形態に係る低炭素鋼冷延鋼帯の製造方法について説明する。この低炭素鋼冷延鋼帯の製造方法は、所定の鋼組成に調製された低炭素鋼のスラブを素材として、熱間圧延工程、酸洗工程等を経て得られた鋼帯に冷間圧延を行い、その後、ウエット調質圧延を行うものである。なお、ウエット調質圧延を採用したことにより、冷間圧延後、被圧延材に付着した冷間圧延油等を除去するための脱脂洗浄処理は省略することが可能である。また、低炭素鋼については冷間圧延による加工硬化が生じ難いことから、冷間圧延後、ウエット調質圧延前に被圧延材を焼鈍処理する工程も省略することが可能である。 Hereinafter, a method for producing a low-carbon steel cold-rolled steel strip according to an embodiment of the present invention will be described. This low carbon steel cold-rolled steel strip manufacturing method uses a low-carbon steel slab prepared in a predetermined steel composition as a raw material, and cold-rolls the steel strip obtained through a hot rolling process, pickling process, etc. After that, wet temper rolling is performed. In addition, by adopting wet temper rolling, it is possible to omit the degreasing cleaning process for removing the cold rolling oil or the like adhering to the material to be rolled after the cold rolling. In addition, since work hardening due to cold rolling is unlikely to occur in low carbon steel, it is possible to omit the step of annealing the material to be rolled after cold rolling and before wet temper rolling.
　上記低炭素鋼冷延鋼帯の鋼材種は、例えば、Ｃ含有量が０.１２質量％以下の低炭素鋼である。この低炭素鋼の代表例としては、ＪＩＳ　Ｇ　３１４１「冷延圧延鋼板及び鋼帯」の「参考」欄に記載された「ＳＰＣＣ」が挙げられる。このＳＰＣＣは、Ｃ含有量が０．１２質量％以下、Ｍｎ含有量が０．５０質量％以下、Ｐ含有量が０．０４０質量％以下、Ｓ含有量が０．０４５質量％以下であり、残部は、Ｆｅおよび不可避不純物からなる。 The steel material type of the low-carbon steel cold-rolled steel strip is, for example, a low-carbon steel having a C content of 0.12% by mass or less. A typical example of this low carbon steel is “SPCC” described in the “Reference” column of JIS G 3141 “Cold rolled steel sheet and steel strip”. This SPCC has a C content of 0.12% by mass or less, an Mn content of 0.50% by mass or less, a P content of 0.040% by mass or less, and an S content of 0.045% by mass or less. The balance consists of Fe and inevitable impurities.
　上記冷間圧延を行う冷間圧延機としては、例えば、圧延方向の逆転が可能なレバース式冷間圧延機を使用することができる。この冷間圧延機のワークロールとしては、１パス目はダルロールを用いる。２パス目以降も、それが最終パスとなる場合を除き、引き続きダルロールを用いる。最終パスではスムースロールを用いる。但し、上記ダルロールは、表面粗度Ｒａが１．０μｍ～１．８μｍのものとすることが望ましく、また、上記スムースロールは、表面粗度Ｒａが０．１μｍ～０．３μｍのものとすることが望ましい。パス数は特に限定されるものではないが、例えばパス数が「５」である場合は、１～４パス目までは、ダルロールを用い、最終パスとなる５パス目のみ、スムースロールを用いる。なお、表面粗度Ｒａは、ＪＩＳ　Ｂ　０６０１で規定されている中心線平均粗さである。なお、冷延圧下率は、鋼帯の用途に応じ適宜決められるものであるが、例えば約５０％～７０％とするのが望ましい。 As the cold rolling mill that performs the cold rolling, for example, a lever type cold rolling mill capable of reversing the rolling direction can be used. As a work roll of this cold rolling mill, a dull roll is used in the first pass. In the second and subsequent passes, the dull roll is continuously used unless it is the final pass. Use a smooth roll in the final pass. However, the dull roll preferably has a surface roughness Ra of 1.0 μm to 1.8 μm, and the smooth roll has a surface roughness Ra of 0.1 μm to 0.3 μm. Is desirable. The number of passes is not particularly limited. For example, when the number of passes is “5”, a dull roll is used for the first to fourth passes, and a smooth roll is used only for the fifth pass as the final pass. The surface roughness Ra is a center line average roughness defined in JIS B 0601. The cold rolling reduction ratio is appropriately determined according to the use of the steel strip, and is preferably about 50% to 70%, for example.
　上記ウエット調質圧延では、ウエット調質圧延機のワークロールとしてブライトロールを用い、ワークロールおよび被圧延材の双方に調質圧延油（潤滑油）を供給しながら圧延が行われる。ウエット調質圧延における鋼帯の伸び率（ε）は、０.２～１.５％の範囲に制御することを要する。この伸び率（ε）に相応する幅荷重は、概ね０．３～０．７Ｔｏｎ／ｍｍ程度である。伸び率（ε）を上記範囲（０.２～１.５％）に限定したのは、これより低い伸び率の調質圧延では、ロール表面の転写効果が弱く製品鋼帯表面の平滑性の不足をきたし、他方その範囲を越える調質圧延では、製品鋼帯の延性の低下が大きく、良好なプレス加工性等を確保し難くなるからである。好ましい伸び率（ε）は、約０.４～１.０％であり、最も好ましくは０.６～０.８％である。 In the wet temper rolling, a bright roll is used as a work roll of a wet temper rolling mill, and rolling is performed while supplying temper rolling oil (lubricating oil) to both the work roll and the material to be rolled. The elongation (ε) of the steel strip in wet temper rolling needs to be controlled in the range of 0.2 to 1.5%. The width load corresponding to the elongation (ε) is about 0.3 to 0.7 Ton / mm. The reason why the elongation (ε) is limited to the above range (0.2 to 1.5%) is that the temper rolling with a lower elongation than this has a weak transfer effect on the roll surface and the smoothness of the surface of the product steel strip. This is because temper rolling exceeding the above range causes a significant decrease in the ductility of the product steel strip, making it difficult to ensure good press workability. The preferred elongation (ε) is about 0.4 to 1.0%, and most preferably 0.6 to 0.8%.
　本願出願人は、従前、冷間圧延機のワークロールとして表面粗度Ｒａが０．４μｍ～０．６μｍのスムースロールを全パスで用いて冷間圧延を行い、その後、当該冷延鋼帯を脱脂洗浄したうえで、ドライ調質圧延して一定の仕様（例えば表面粗度Ｒａが０．３μｍ以下）を満たす製品鋼帯（低炭素鋼冷延鋼帯）を製造していた。この製造方法では、製品鋼帯に時々押し込み疵が発生していたため、本願発明者は、製品鋼帯が上記一定の仕様を満たしつつ押し込み疵の発生を完全に防止することが可能な低炭素鋼冷延鋼帯の製造方法について鋭意実験研究を積み重ねた。 The applicant of the present application has previously performed cold rolling using a smooth roll having a surface roughness Ra of 0.4 μm to 0.6 μm in all passes as a work roll of a cold rolling mill. After degreasing and cleaning, dry temper rolling was performed to produce a product steel strip (low carbon steel cold-rolled steel strip) that satisfies a certain specification (for example, surface roughness Ra is 0.3 μm or less). In this manufacturing method, since indentation flaws were occasionally generated in the product steel strip, the inventor of the present application is able to completely prevent the occurrence of indentation flaws while the product steel strip satisfies the above-mentioned certain specifications. The earnest experimental research was accumulated about the manufacturing method of the cold-rolled steel strip.
　その結果、本願発明者は、調質圧延としてウエット調質圧延を採用することにより、押し込み疵の発生を完全に防止することを前提として、ブライトロールの転写効率の低下の問題については、冷間圧延において使用するワークロールの表面粗度に着目して解決するに至った。つまり、既述したように、冷間圧延において、１パス目はダルロールを用い、２パス目以降も、最終パスとなる場合を除き、引き続きダルロールを用い、最終パスでスムースロールを用いることにより、ウエット調質圧延後の製品鋼帯が上記一定の仕様を満たすことが可能であるという知見を得た。 As a result, the inventor of the present application adopted a wet temper rolling as a temper rolling, and on the premise that generation of indentation flaws is completely prevented, It came to solve it paying attention to the surface roughness of the work roll used in rolling. That is, as described above, in cold rolling, the first pass uses a dull roll, and the second pass and beyond, except when the final pass is used, the dull roll is used continuously, and the smooth pass is used in the final pass. It was found that the product steel strip after wet temper rolling can satisfy the above-mentioned certain specifications.
　このように冷間圧延機のワークロールの表面粗度を変更することにより、製品鋼帯が上記一定の仕様を満たすことが可能となる理由は、オイルピットの形成が関わっていると考えられる。冷間圧延を行うときは、被圧延材およびワークロールに圧延油が供給されながらこれらの被圧延材およびワークロールの冷却、潤滑が行われる。従前のように、全パスについて表面粗度Ｒａが０．４μｍ～０．６μｍのスムースロールを用いて冷間圧延を行った場合、被圧延材にオイルピットが形成されてしまい、冷間圧延後の被圧延材には多数のオイルピットが形成されてしまう。 The reason why the product steel strip can satisfy the above-mentioned specific specifications by changing the surface roughness of the work roll of the cold rolling mill is considered to be related to the formation of oil pits. When performing cold rolling, cooling and lubrication of the material to be rolled and the work roll are performed while supplying rolling oil to the material to be rolled and the work roll. As before, when cold rolling is performed using a smooth roll having a surface roughness Ra of 0.4 μm to 0.6 μm for all passes, oil pits are formed in the material to be rolled, and after cold rolling, A large number of oil pits are formed in the material to be rolled.
　本実施形態における冷間圧延のように、最終パス以外でワークロールとしてダルロールを用いる場合、ダルロールを使用中は、ダルロールの表面の凹凸に圧延油が入り込み当該表面がオイルピットとして機能するため、被圧延材にオイルピットが形成され難くなる。そして、最終パスで、表面粗度Ｒａが０．１μｍ～０．３μｍのスムースロール（従前用いていたスムースロールよりも表面粗度が格段に小さなもの）を用いることで、冷間圧延後の被圧延材の表面粗度は、従前より格段に小さくなり、ウエット調質圧延において被圧延材に対するブライトロールの転写効率が低くなっても、その転写効率の低下分を補って、調質圧延後の製品鋼帯の表面粗度を十分に確保できる。つまり、前記一定の仕様（表面粗度Ｒａが０．３μｍ以下）を満たすことが可能となる。 When using a dull roll as a work roll other than the final pass as in the cold rolling in the present embodiment, the rolling oil enters the irregularities on the surface of the dull roll and the surface functions as an oil pit when the dull roll is used. Oil pits are hardly formed on the rolled material. Then, in the final pass, by using a smooth roll having a surface roughness Ra of 0.1 μm to 0.3 μm (having a surface roughness much smaller than the previously used smooth roll), the coated film after cold rolling is used. The surface roughness of the rolled material is much smaller than before, and even if the transfer efficiency of the bright roll to the material to be rolled is reduced in wet temper rolling, it compensates for the decrease in the transfer efficiency, and after temper rolling The surface roughness of the product steel strip can be secured sufficiently. That is, it becomes possible to satisfy the certain specification (surface roughness Ra is 0.3 μm or less).
　以上のように、本発明の実施の形態に係る低炭素鋼冷延鋼帯の製造方法によれば、冷間圧延の後に行う調質圧延としてウエット方式を採用し、調質圧延機のワークロールおよび被圧延材の双方に調質圧延油が供給され、当該調質圧延油の洗浄作用によってワークロールや被圧延材の表面に付着した異物が洗い流されるので被圧延材における押し込み疵の発生を防止することができる。また、冷間圧延の１パス目は表面粗度Ｒａが１．０μｍ～１．８μｍのダルロールを用い、２パス目以降も、最終パスとなる場合を除き、引き続き同じダルロールを用い、最終パスで表面粗度Ｒａが０．１μｍ～０．３μｍのスムースロールを用いた冷間圧延を実施することにより、ウエット調質圧延を採用しても従前と同レベルの表面粗度（例えば表面粗度Ｒａが０．３μｍ以下）の製品鋼帯を製造することが可能である。 As described above, according to the manufacturing method of the low-carbon steel cold-rolled steel strip according to the embodiment of the present invention, the wet roll is adopted as the temper rolling performed after the cold rolling, and the work roll of the temper rolling mill The tempered rolling oil is supplied to both the rolled material and the rolled material, and the foreign matter adhering to the work roll and the surface of the rolled material is washed away by the cleaning action of the tempered rolling oil, so that the occurrence of indentation flaws in the rolled material is prevented. can do. Also, the first pass of cold rolling uses a dull roll having a surface roughness Ra of 1.0 μm to 1.8 μm, and the second pass and thereafter continue to use the same dull roll except for the final pass. By carrying out cold rolling using a smooth roll having a surface roughness Ra of 0.1 μm to 0.3 μm, even if wet temper rolling is employed, the same surface roughness (for example, surface roughness Ra) Can produce a product steel strip of 0.3 μm or less).
　以下、本発明の実施例について説明する。この実施例では、低炭素鋼スラブを素材とし、熱間圧延および熱延鋼板の酸洗処理（脱スケール処理）を経由して得られる被圧延材に対し、冷間圧延を行う。冷間圧延は１～４パス目まで表面粗度Ｒａが１．０μｍ～１．８μｍのダルロールをワークロールとして用い、最終パスである５パス目で表面粗度Ｒａが０．１μｍ～０．３μｍのスムースロールをワークロールとして用いる。これにより得られた冷延鋼帯を脱脂洗浄処理することなく、ウエット調質圧延を施して表面粗度を調整した製品鋼帯（低炭素鋼冷延鋼帯）を得た。この鋼帯は、ＳＰＣＣ－１Ｂ（ＪＩＳ　Ｇ３１４１）相当の板材（調質区分：硬質、表面仕上げ区分：ブライト仕上げ）である。 Hereinafter, examples of the present invention will be described. In this embodiment, a low-carbon steel slab is used as a raw material, and cold rolling is performed on a material to be rolled obtained through hot rolling and pickling treatment (descaling treatment) of a hot-rolled steel sheet. In cold rolling, a dull roll having a surface roughness Ra of 1.0 μm to 1.8 μm is used as a work roll in the first to fourth passes, and the surface roughness Ra is 0.1 μm to 0.3 μm in the fifth pass as the final pass. The smooth roll is used as a work roll. A product steel strip (low-carbon steel cold-rolled steel strip) having a surface roughness adjusted by wet temper rolling was obtained without degreasing and washing the cold-rolled steel strip obtained in this way. This steel strip is a plate material equivalent to SPCC-1B (JIS G3141) (tempering classification: hard, surface finishing classification: bright finish).
　また、従前の低炭素鋼冷延鋼帯の製造方法として、低炭素鋼スラブを素材とし、熱間圧延および熱延鋼板の酸洗処理を経由して得られる被圧延材に対し、１～５パス目まで表面粗度Ｒａが０．４μｍ～０．６μｍのスムースロールをワークロールとして用いて冷間圧延を行い、これにより得られた冷延鋼帯を脱脂洗浄処理したうえで、ドライ調質圧延を施して表面粗度を調整した製品鋼（低炭素鋼冷延鋼帯）帯も得た。この鋼帯も、ＳＰＣＣ－１Ｂ（ＪＩＳ　Ｇ３１４１）相当の板材（調質区分：硬質、表面仕上げ区分：ブライト仕上げ）である。 In addition, as a conventional method for producing a low-carbon steel cold-rolled steel strip, a low-carbon steel slab is used as a raw material, and the rolled material obtained through hot rolling and pickling treatment of a hot-rolled steel plate is 1-5. Cold rolling is performed using a smooth roll with a surface roughness Ra of 0.4 μm to 0.6 μm as a work roll up to the pass, and the resulting cold-rolled steel strip is degreased and washed, and then dry tempered A product steel (low-carbon steel cold-rolled steel strip) strip whose surface roughness was adjusted by rolling was also obtained. This steel strip is also a plate material equivalent to SPCC-1B (JIS G3141) (tempering classification: hard, surface finishing classification: bright finish).
　本発明の実施例に係る製造方法および従前の製造方法における鋼組成、熱間圧延条件、冷間圧延条件は、何れも次の（１）～（３）通りである。すなわち、（１）鋼組成は、Ｃ含有量が０．０２～０．０６質量％、Ｍｎ含有量が０．４～０．４８質量％、Ｐ含有量が０．０２質量％、Ｓ含有量が０．０１質量％である。（２）熱間圧延条件は、熱延仕上げ温度が８７５～９３５℃、巻取り温度が５３５～６３５℃である。（３）冷間圧延条件は、圧下率が５２．６％、冷延板厚が１．６１ｍｍである。 The steel composition, hot rolling conditions, and cold rolling conditions in the manufacturing method according to the embodiment of the present invention and the conventional manufacturing method are as follows (1) to (3). That is, (1) Steel composition has a C content of 0.02 to 0.06 mass%, an Mn content of 0.4 to 0.48 mass%, a P content of 0.02 mass%, and an S content. Is 0.01% by mass. (2) The hot rolling conditions are a hot rolling finishing temperature of 875 to 935 ° C. and a winding temperature of 535 to 635 ° C. (3) The cold rolling conditions are a rolling reduction of 52.6% and a cold-rolled sheet thickness of 1.61 mm.
　調質圧延条件としては、ワークロールとして湿式研削処理（粒度＃３２０の研削砥石使用）を施した平滑面を有するブライトロールを使用した。ウエット調質圧延では、調質圧延油として「ＮＤ－１０改」（大同化学株式会社製）を濃度６％で使用した。いずれの調質圧延でも鋼帯伸び率を０．６～０．７％とした。 As the temper rolling conditions, a bright roll having a smooth surface subjected to a wet grinding process (using a grinding wheel of grain size # 320) was used as a work roll. In the wet temper rolling, “ND-10 Kai” (manufactured by Daido Chemical Co., Ltd.) was used as a temper rolling oil at a concentration of 6%. In any temper rolling, the steel strip elongation was 0.6 to 0.7%.
　図１に本発明の実施例に係る製造方法により得られた製品鋼帯の表面粗度の測定結果を示し、図２に従前の製造方法により得られた製品鋼帯の表面粗度の測定結果を示す。図１に示すように、本発明の実施例に係る製造方法により得られた製品鋼帯は、Ｎ数（製造個数）が２１、表面粗度Ｒａの平均値が０．１４８（０．１５４）、標準偏差が０．０１１（０．０１１）、最大値が０．１６９（０．１７１）、最小値が０．１２５（０．１３２）となった。なお、（）外の値は鋼帯の表面（つまり上面）、（）内の値は鋼帯の裏面（つまり下面）を示す。この製造方法により得られた製品鋼帯に押し込み疵は発見されなかった。 FIG. 1 shows the measurement result of the surface roughness of the product steel strip obtained by the manufacturing method according to the embodiment of the present invention, and the measurement result of the surface roughness of the product steel strip obtained by the previous manufacturing method of FIG. Indicates. As shown in FIG. 1, the product steel strip obtained by the manufacturing method according to the embodiment of the present invention has an N number (production number) of 21 and an average value of the surface roughness Ra of 0.148 (0.154). The standard deviation was 0.011 (0.011), the maximum value was 0.169 (0.171), and the minimum value was 0.125 (0.132). In addition, the value outside () shows the surface (namely, upper surface) of a steel strip, and the value inside () shows the back surface (namely, lower surface) of a steel strip. No indentation flaws were found in the product steel strip obtained by this manufacturing method.
　これに対して、従前の製造方法により得られた製品鋼帯は、Ｎ数（製造個数）が３０４（３０４）、表面粗度Ｒａの平均値が０．１５１（０．１６９）、標準偏差が０．０３５（０．０３３）、最大値が０．２８４（０．２９２）、最小値が０．０７８（０．０７５）となった。 On the other hand, the product steel strip obtained by the conventional manufacturing method has an N number (production number) of 304 (304), an average value of the surface roughness Ra of 0.151 (0.169), and a standard deviation. The maximum value was 0.035 (0.033), the maximum value was 0.284 (0.292), and the minimum value was 0.078 (0.075).
　両製造方法を比較すると、Ｎ数が大きく相違しているため、表面粗度Ｒａの標準偏差、最大値および最長値が大きく相違しているが、表面粗度Ｒａの平均値は概ね等しいといえる。つまり、本発明の実施例に係る製造方法によれば、従前の製造方法により製造された冷延鋼帯と同程度の表面粗度Ｒａを有するものを製造することができるといえる。 When the two manufacturing methods are compared, since the N number is greatly different, the standard deviation, the maximum value, and the longest value of the surface roughness Ra are greatly different, but the average value of the surface roughness Ra is substantially equal. . That is, according to the manufacturing method according to the example of the present invention, it can be said that a steel sheet having the same surface roughness Ra as that of the cold-rolled steel strip manufactured by the conventional manufacturing method can be manufactured.
　本発明は、例えば、表面平滑性に優れた低炭素鋼冷延鋼帯を製造するための製造ラインに適用可能であり、製造された低炭素鋼冷延鋼帯は、機械部品、電気・電子機器部品、自動車部品等に好適に使用される。 The present invention can be applied to, for example, a production line for producing a low-carbon steel cold-rolled steel strip excellent in surface smoothness, and the produced low-carbon steel cold-rolled steel strip includes mechanical parts, electric / electronic It is suitably used for equipment parts, automobile parts and the like.

Claims (4)

  1. 　低炭素鋼からなる鋼帯を冷間圧延した後、ブライトロールを用いてウエット調質圧延を行う低炭素鋼冷延鋼帯の製造方法において、
    　前記冷間圧延は、少なくとも１パスをダルロールを用いて実施した後、最終パスをスムースロールを用いて実施するものである、ことを特徴とする低炭素鋼冷延鋼帯の製造方法。     In the method for producing a low-carbon steel cold-rolled steel strip, cold-rolling a steel strip made of low-carbon steel and then performing wet temper rolling using a bright roll,
    The cold rolling is performed by performing at least one pass using a dull roll, and then performing a final pass using a smooth roll.
  2. 　請求項１に記載の低炭素鋼冷延鋼帯の製造方法において、
    　前記ウエット調質圧延を行った冷延鋼帯の表面粗度Ｒａは０．３μｍ以下であることを特徴とする低炭素鋼冷延鋼帯の製造方法。     In the manufacturing method of the low carbon steel cold-rolled steel strip according to claim 1,
    The method for producing a low-carbon steel cold-rolled steel strip, wherein the cold-rolled steel strip subjected to the wet temper rolling has a surface roughness Ra of 0.3 μm or less.
  3. 　請求項１に記載の低炭素鋼冷延鋼帯の製造方法において、
    　前記スムースロールの表面粗度Ｒａは０．１μｍ～０．３μｍであることを特徴とする低炭素鋼冷延鋼帯の製造方法。     In the manufacturing method of the low carbon steel cold-rolled steel strip according to claim 1,
    The method for producing a low-carbon steel cold-rolled steel strip, wherein the smooth roll has a surface roughness Ra of 0.1 μm to 0.3 μm.
  4. 　請求項１又は３に記載の低炭素鋼冷延鋼帯の製造方法において、
    　前記ダルロールの表面粗度Ｒａは１．０μｍ～１．８μｍであることを特徴とする低炭素鋼冷延鋼帯の製造方法。     In the manufacturing method of the low carbon steel cold-rolled steel strip according to claim 1 or 3,
    A method for producing a low carbon steel cold-rolled steel strip, wherein the dull roll has a surface roughness Ra of 1.0 μm to 1.8 μm.
PCT/JP2013/071193 2013-08-06 2013-08-06 Process for producing cold-rolled low-carbon-steel strip WO2015019409A1 (en)

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