JPH10204540A - Production of cold rolled high-carbon steel strip - Google Patents
Production of cold rolled high-carbon steel stripInfo
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- JPH10204540A JPH10204540A JP1737697A JP1737697A JPH10204540A JP H10204540 A JPH10204540 A JP H10204540A JP 1737697 A JP1737697 A JP 1737697A JP 1737697 A JP1737697 A JP 1737697A JP H10204540 A JPH10204540 A JP H10204540A
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Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、均一な形状、特性
を有し、かつ比較的軟質で良好な加工特性を有する高炭
素冷延鋼帯を工業的に安定して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 industrially and stably producing a high-carbon cold-rolled steel strip having a uniform shape and properties, a relatively soft and good working property.
【０００２】[0002]
【従来の技術】一般に、刃物、ゼンマイ、ワッシャー、
バネ、シートベルト金具、その他の高硬度機械部品は、
ＪＩＳ Ｇ ３３１１に規定のみがき特殊鋼帯である高
炭素冷延鋼帯を素材とし、打抜き、曲げ、プレス加工、
切削等の加工工程と、焼入れ、焼戻し、その他の熱処理
工程とを経て製造される。その製品品質の向上、安定
化、製造コストの低減を図るには、素材の高炭素冷延鋼
帯が軟質で加工性がよく、かつ組織の均一性に優れてい
ることが必要である。2. Description of the Related Art Generally, blades, springs, washers,
Spring, seat belt fittings and other high-hardness machine parts
A high carbon cold-rolled steel strip, a special steel strip specified in JIS G 3311, is used as a material for punching, bending, pressing,
It is manufactured through a processing step such as cutting, quenching, tempering, and other heat treatment steps. In order to improve the product quality, stabilize, and reduce the manufacturing cost, it is necessary that the high-carbon cold-rolled steel strip as the material is soft, has good workability, and has excellent structure uniformity.
【０００３】上記高炭素冷延鋼帯は、熱延鋼帯を酸洗し
たのち、冷間圧延と焼鈍が施され、所望の硬度に調整さ
れて製造されるが、加工前には軟質で加工し易く、加工
後に施される熱処理において所定の硬度が得られ、か
つ、製品としての使用に十分な硬度と耐摩耗性が要求さ
れる。そのため、冷間圧延後の焼鈍は、高温で処理する
必要があり、このために鋼帯同志の密着による焼付疵が
発生し易いが、鋼帯表面はその用途上、光沢性を要求さ
れるために厳しい表面検査により焼鈍焼付疵による品質
不良が発生し易いという問題がある。[0003] The high-carbon cold-rolled steel strip is manufactured by pickling a hot-rolled steel strip, then cold rolling and annealing to adjust the hardness to a desired hardness. It is required to have a predetermined hardness by heat treatment performed after processing, and to have sufficient hardness and abrasion resistance for use as a product. Therefore, annealing after cold rolling must be performed at a high temperature, and as a result, seizure flaws are likely to occur due to close contact between steel strips. There is a problem that poor quality is liable to occur due to annealing seizure due to severe surface inspection.
【０００４】従来、高炭素冷延鋼帯を軟質で加工し易い
組織にするための方法としては、熱間圧延においてラン
アウトテーブル上で急冷して相変態を完了させ、その相
変態を完了した鋼帯を５００〜６２０℃で巻取った高炭
素熱延鋼帯を母材として、該母材を圧下率２０％以上で
冷間圧延し、その後ベル型炉にてＡｃ１点以上７７０℃
以下の温度で焼鈍する方法（特開昭５８−５５５３２号
公報）、Ｃ：０．２７〜０．９０％、Ｓｉ：０．１５〜
０．３０％、Ｍｎ：０．６０〜０．９０％、Ｐ：０．０
３０％以下、Ｓ：０．０３５％以下、残部Ｆｅおよび不
可避的不純物からなる鋼に通常の熱間圧延を施し、次い
で酸洗して得られる熱延鋼帯を出発材として、高炭素冷
延鋼帯を製造する方法において、前記出発材としての熱
延鋼帯を６８０〜７２０℃の温度に１５時間以上保持す
る一次焼鈍を行い、次いで２０〜４５％の圧下率で冷間
圧延を行い、その後６３０〜７２０℃の温度で１０時間
以上保持する仕上焼鈍を行う方法（特開昭６１−７６６
１９号公報）、高炭素鋼を熱間圧延してからの冷却にお
いて、冷却速度を炭素量０．６％未満では３０〜４５℃
／ｓｅｃ、炭素量０．６％以上では１５〜４５℃／ｓｅ
ｃとし、その後の巻取りを炭素量０．６％未満では４６
０〜６００℃、炭素量０．６％以上０．８％未満で５５
０〜６４０℃、炭素量０．８％以上では６２０〜６８０
℃で行い、冷間圧延を炭素量０．６％未満では圧下率５
０〜８５％、炭素量０．６％以上０．８％未満では３０
〜７０％、炭素量０．８％以上では２５〜６０％で実施
した後、球状化焼鈍を炭素量０．８％未満では６８０〜
Ａｃ１点、炭素量０．８％以上では６８０〜７５０℃で
施す方法（特開平３−１２２２１６号公報）、Ｃ：０．
３％以上の高炭素熱延鋼板に、中間冷間圧延を圧下率４
５％以上で行った後、中間焼鈍を箱焼鈍によりＣ：０．
８％未満の場合は６８０℃〜Ａｃ１点、Ｃ：０．８％以
上の場合は６８０〜７５０℃で、２０〜４０時間均熱し
て施し、最終冷間圧延を圧下率が１３％以上とし、しか
も中間冷間圧延前後の板厚および最終冷間圧延後の板厚
をそれぞれｔ0、ｔ1およびｔ2とするとき、中間冷間圧
延の圧下比の対数ｌｎ（ｔ0／ｔ1）に対して、最終冷間
圧延の圧下比の対数ｌｎ（ｔ1／ｔ2）が０．５倍以下と
なるようにして行い、最終焼鈍を箱焼鈍により５５０〜
７００℃で１〜６時間均熱して施す方法（特公平７−１
１６５１９号公報）、Ｃ：０．６〜１．３％、Ｓｉ：
０．５％以下、Ｍｎ：１％以下、Ｃｒ：１．６％以下、
残部実質的にＦｅからなる化学組成を有する高炭素熱延
鋼帯を、水素５０容量％以上で、残部が窒素である雰囲
気炉中、Ａｃ１点〜７８０℃の温度域に１時間以上均熱
保持後、６０℃／Ｈｒ以下の冷却速度でＡｒ１点直下ま
で冷却する第１段の均熱・徐冷と、Ａｃ１点直下に３〜
２０時間均熱保持後、６０℃／Ｈｒ以下の冷却速度でＡ
ｒ１点以下まで冷却する第２段の均熱・徐冷とからなる
一次焼鈍処理に付した後、冷間圧延を行い、ついで６０
０℃〜Ａｃ１点直下の温度域での二次焼鈍処理を施す方
法（特開平４−２０２６２９号公報）等が提案されてい
る。Conventionally, as a method for forming a high-carbon cold-rolled steel strip into a soft and easy-to-work structure, in hot rolling, rapid transformation is performed on a run-out table to complete the phase transformation, and the steel having undergone the phase transformation is completed. Using a high-carbon hot-rolled steel strip obtained by winding the strip at 500 to 620 ° C as a base material, the base material is cold-rolled at a rolling reduction of 20% or more, and then, at a point of Ac 1 point or more and 770 ° C in a bell furnace.
A method of annealing at the following temperature (Japanese Patent Laid-Open No. 58-55532), C: 0.27 to 0.90%, Si: 0.15 to
0.30%, Mn: 0.60 to 0.90%, P: 0.0
30% or less, S: 0.035% or less, steel containing normal balance of Fe and unavoidable impurities is subjected to ordinary hot rolling, and then hot-rolled steel strip obtained by pickling is used as a starting material to start high-carbon cold rolling. In the method for producing a steel strip, primary annealing is performed by holding the hot-rolled steel strip as the starting material at a temperature of 680 to 720 ° C for 15 hours or more, and then cold rolling is performed at a rolling reduction of 20 to 45%, Thereafter, a method of performing finish annealing in which the temperature is maintained at a temperature of 630 to 720 ° C. for 10 hours or more (Japanese Patent Application Laid-Open No. 61-766)
No. 19), in the cooling after hot rolling of high carbon steel, if the cooling rate is less than 0.6% carbon, the cooling rate is 30 to 45 ° C.
/ Sec, 15 to 45 ° C / sec when the carbon content is 0.6% or more.
and the subsequent winding is 46 if the carbon content is less than 0.6%.
0 to 600 ° C, 55% for carbon content of 0.6% or more and less than 0.8%
0 to 640 ° C, 620 to 680 when the carbon content is 0.8% or more
C., and cold rolling is performed at a rolling reduction of 5% if the carbon content is less than 0.6%.
0 to 85%, 30 for carbon content of 0.6% or more and less than 0.8%
After performing the spheroidizing annealing at a carbon content of 0.8% or more at 25 to 60%, the spheroidizing annealing is performed at a carbon content of less than 0.8% at 680 to 70%.
When the Ac point is 1 and the carbon content is 0.8% or more, the method is carried out at 680 to 750 ° C. (JP-A-3-122216).
Intermediate cold rolling of high-carbon hot-rolled steel sheets of 3% or more with a rolling reduction of 4
After performing at 5% or more, the intermediate annealing was performed by box annealing to obtain C: 0.
If it is less than 8%, it is 680 ° C. to Ac1 point, and if it is 0.8% or more, it is soaked at 680 to 750 ° C. for 20 to 40 hours, and the final cold rolling is performed with a rolling reduction of 13% or more. Moreover, when the sheet thickness before and after the intermediate cold rolling and the sheet thickness after the final cold rolling are t 0 , t 1 and t 2 , respectively, the logarithm of the reduction ratio ln (t 0 / t 1 ) of the intermediate cold rolling is obtained. On the other hand, the logarithm ln (t 1 / t 2 ) of the reduction ratio of the final cold rolling is set to be 0.5 times or less, and the final annealing is performed by box annealing to 550 to 550.
Heating at 700 ° C for 1 to 6 hours
No. 16519), C: 0.6 to 1.3%, Si:
0.5% or less, Mn: 1% or less, Cr: 1.6% or less,
A high-carbon hot-rolled steel strip having a chemical composition substantially consisting of Fe is heated to 50% by volume or more of hydrogen and kept in a temperature range of Ac 1 point to 780 ° C. for 1 hour or more in an atmosphere furnace in which the balance is nitrogen. Thereafter, the first stage of soaking / slow cooling to cool directly below the Ar 1 point at a cooling rate of 60 ° C./Hr or less, and 3 to 3 immediately below the Ac 1 point.
After maintaining the soaking temperature for 20 hours, A was cooled at a cooling rate of 60 ° C./Hr or less.
After being subjected to a primary annealing treatment comprising a second stage of soaking and gradual cooling in which the temperature is lowered to r1 or lower, cold rolling is performed, and then 60
A method of performing a secondary annealing treatment in a temperature range from 0 ° C. to just below the Ac1 point (JP-A-4-202629) has been proposed.
【０００５】[0005]
【発明が解決しようとする課題】上記特開昭５８−５５
５３２号公報に開示の方法は、冷間圧延前の焼鈍工程を
省略し、酸洗した後冷間圧延し、その後の焼鈍をＡｃ１
点以上で実施するものであるが、前記したとおり高炭素
冷延鋼帯表面はブライト肌であるため、バッチコイル焼
鈍炉で処理する限りはＡｃ１点以上の高温焼鈍のため、
焼鈍焼付き疵が発生し、実生産設備では安定して高炭素
冷延鋼帯を製造することは困難である。しかも、この方
法は、熱間圧延のランアウトテーブル上で急冷して相変
態を完了した鋼帯を５００〜６２０℃で巻取った高炭素
熱延鋼帯を母材として使用するのが前提であるが、５５
０℃以下では母材の延性が低下し、次工程での酸洗ライ
ン内破断や、冷間圧延時の破断が発生するため、操業を
著しく阻害するという欠点を有している。SUMMARY OF THE INVENTION The above-mentioned JP-A-58-55 is disclosed.
No. 532 discloses a method in which an annealing step before cold rolling is omitted, pickling is performed, then cold rolling is performed, and the subsequent annealing is performed using Ac1.
As described above, since the surface of the high-carbon cold-rolled steel strip has a bright skin as described above, as long as it is processed in a batch coil annealing furnace, it is for high-temperature annealing of more than Ac1 point.
Anneal seizure flaws occur, and it is difficult to stably produce high-carbon cold-rolled steel strip with actual production equipment. In addition, this method is based on the premise that a high-carbon hot-rolled steel strip obtained by winding a steel strip which has been rapidly cooled on a hot-rolling run-out table and phase transformation is completed at 500 to 620 ° C. is used as a base material. But 55
If the temperature is 0 ° C. or lower, the ductility of the base material is reduced, and breakage in the pickling line in the next step or breakage during cold rolling occurs, which has a disadvantage that the operation is significantly impaired.
【０００６】また、特開昭６１−７６６１９号公報に開
示の方法は、熱延鋼帯の一次焼鈍温度が６８０〜７２０
℃とＡｃ１点以下であるため、十分に軟質な高炭素鋼帯
が得られない。In the method disclosed in Japanese Patent Application Laid-Open No. 61-76619, the primary annealing temperature of a hot-rolled steel strip is 680 to 720.
° C and the Ac1 point or less, a sufficiently soft high carbon steel strip cannot be obtained.
【０００７】さらに、特開平３−１２２２１６号公報に
開示の方法は、中間焼鈍温度がＡｃ１点以下のため焼鈍
時間が２０〜４０時間も必要となり、能率面で不利であ
る。Further, the method disclosed in Japanese Patent Application Laid-Open No. 3-122216 is disadvantageous in terms of efficiency because the intermediate annealing temperature is lower than the Ac1 point, requiring an annealing time of 20 to 40 hours.
【０００８】さらにまた、特公平７−１１６５１９号公
報に開示の方法は、中間焼鈍を６８０℃〜Ａｃ１点以下
で２０〜４０時間行うため、能率面で不利であり、実生
産設備では無駄が多い。また、特開平３−２１１２３５
号公報中には、「中間焼鈍温度がＡｃ１点より高いと
Ｃ：０．６％以下の鋼ではフェライト相が生成するため
球状化率が低下し、Ｃ：０．６％超でも一部が完全にオ
ーステナイト化するため、焼鈍後の冷却において粗いパ
ーライトが生成し、やはり球状化率が低下する。」との
記載があり、Ｃ：０．３〜０．８％の高炭素熱延鋼帯で
は、球状化率が低下することは避けられないという問題
点を有している。しかも、仕上焼鈍温度を箱焼鈍により
５５０〜７００℃で１〜６時間均熱して施すが、軟化の
ためには焼鈍温度を高くする必要があり、高炭素熱延鋼
帯では、焼付き疵が発生するため低温で焼鈍せざるを得
ず、薄物材の軟化焼鈍は困難である。Furthermore, the method disclosed in Japanese Patent Publication No. Hei 7-116519 is disadvantageous in terms of efficiency because the intermediate annealing is performed at 680 ° C. to an Ac point or less for 20 to 40 hours, and wasteful in actual production equipment. . Also, Japanese Patent Application Laid-Open No. Hei 3-21235
In the gazette, "If the intermediate annealing temperature is higher than the Ac1 point, the steel having a C: 0.6% or less generates a ferrite phase, so that the spheroidization ratio is reduced. Because of the complete austenitization, coarse pearlite is generated during cooling after annealing, and the spheroidization rate is also lowered. "C: 0.3 to 0.8% high carbon hot rolled steel strip However, there is a problem that the spheroidization rate cannot be reduced. Moreover, the final annealing temperature is soaked by box annealing at 550 to 700 ° C. for 1 to 6 hours. However, it is necessary to increase the annealing temperature for softening. Since it occurs, it has to be annealed at a low temperature, and soft annealing of a thin material is difficult.
【０００９】また、特開平４−２０２６２９号公報に開
示の方法は、Ａｃ１点以上７８０℃以下の温度まで焼鈍
温度を上げた際の均熱時間を１時間以上としているが、
上限が明記されていない。Ａｃ１点以上での長時間焼鈍
は、後述するとおり焼鈍後に球状セメンタイトを得るこ
とが困難であり、加工後はかえって劣化し、その後冷間
圧延、焼鈍を繰り返しても、高炭素鋼帯の加工性の向上
は望めない。さらに、コイル焼鈍においてＡｃ１点以上
で短時間焼鈍を実現するための具体的な方法が開示され
ていないため、実機では良好な球状化組織を安定して得
ることが不可能である。In the method disclosed in Japanese Patent Application Laid-Open No. Hei 4-202629, the soaking time when the annealing temperature is raised to a temperature between Ac 1 point and 780 ° C. is 1 hour or more.
No upper limit is specified. As described later, it is difficult to obtain spherical cementite after annealing for a long time at an Ac point or more, and it is rather deteriorated after working. Even after repeated cold rolling and annealing, the workability of a high carbon steel strip is improved. Improvement cannot be expected. Further, since no specific method for realizing short-time annealing at an Ac1 point or higher in coil annealing is not disclosed, it is impossible to stably obtain a good spheroidized structure with an actual machine.
【００１０】本発明の目的は、上記従来技術の問題点を
解消し、従来の高炭素冷延鋼帯と同等以上の加工性を有
し、かつ結晶組織の均質性に優れた高炭素冷延鋼帯を、
焼鈍時間の短縮を実現しつつ、焼付き疵の発生を防止し
て安価に安定して製造できる高炭素冷延鋼帯の製造方法
を提供することにある。An object of the present invention is to solve the above-mentioned problems of the prior art, to provide a high carbon cold rolled steel sheet having workability equal to or higher than that of a conventional high carbon cold rolled steel strip and having excellent crystal structure homogeneity. Steel strip,
An object of the present invention is to provide a method of manufacturing a high-carbon cold-rolled steel strip that can stably produce at low cost while preventing the occurrence of seizure flaws while shortening the annealing time.
【００１１】[0011]
【課題を解決するための手段】本発明の請求項１の高炭
素冷延鋼帯の製造方法は、Ｃ：０．３〜０．８％、Ｓ
ｉ：０．０３〜０．３５％、Ｍｎ：０．２０〜１．５０
％を含有し、残部が実質的にＦｅおよび不可避的不純物
からなる高炭素鋼片を、熱間圧延、酸洗、脱スケールし
たのち、冷間圧延を圧下率２５％以上８０％以下で実施
後、７５容量％以上の水素と残部が実質的に窒素および
不可避的不純物からなるガス雰囲気のベル型バッチ焼鈍
炉を用い、下記（１）〜（９）の焼鈍条件で焼鈍するこ
ととしている。 （１） 第１段均熱温度までの加熱速度：２０℃／Ｈｒ
〜１００℃／Ｈｒ （２） 第１段均熱温度×時間：Ａｃ１点〜Ａｃ１点＋
５０℃×８Ｈｒ以下 （３） 第１段均熱完了後の冷却速度：５０℃／Ｈｒ以
下 （４） 第１段冷却完了時の冷却到達温度：Ａｒ１点以
下 （５） 第２段均熱温度までの加熱速度：２０℃／Ｈｒ
〜１００℃／Ｈｒ （６） 第２段均熱温度×時間：Ａｃ１点〜Ａｃ１点＋
５０℃×８Ｈｒ以下 （７） 第２段均熱完了後の冷却速度：５０℃／Ｈｒ以
下 （８） 第２段冷却完了時の冷却到達温度：Ａｒ１点以
下 （９） 以降は２０℃／Ｈｒ〜１００℃／Ｈｒで室温ま
で冷却According to the first aspect of the present invention, there is provided a method for producing a high-carbon cold-rolled steel strip, comprising: C: 0.3 to 0.8%;
i: 0.03 to 0.35%, Mn: 0.20 to 1.50
%, The balance being substantially Fe and unavoidable impurities, after hot rolling, pickling and descaling, and then performing cold rolling at a rolling reduction of 25% or more and 80% or less. And a bell-type batch annealing furnace in a gas atmosphere consisting of 75% by volume or more of hydrogen and the balance substantially consisting of nitrogen and unavoidable impurities, and performing annealing under the following annealing conditions (1) to (9). (1) Heating rate up to the first stage soaking temperature: 20 ° C / Hr
１００100 ° C./Hr (2) First-stage soaking temperature × time: Ac1 point to Ac1 point +
(3) Cooling rate after completion of first-stage soaking: 50 ° C / Hr or less (4) Ultimate cooling temperature after completion of first-stage cooling: Ar1 point or less (5) Second-stage soaking temperature Heating rate up to: 20 ° C / Hr
１００100 ° C./Hr (6) Second stage soaking temperature × time: Ac1 point to Ac1 point +
(7) Cooling rate after completion of second-stage soaking: 50 ° C / Hr or less (8) Ultimate cooling temperature after completion of second-stage cooling: Ar 1 point or less (9) After that, 20 ° C / Hr Cool to room temperature at ~ 100 ° C / Hr
【００１２】このように、Ｃ：０．３〜０．８％、Ｓ
ｉ：０．０３〜０．３５％、Ｍｎ：０．２０〜１．５０
％を含有し、残部が実質的にＦｅおよび不可避的不純物
からなる高炭素鋼片を、熱間圧延、酸洗、脱スケールし
たのち、冷間圧延を圧下率２５％以上８０％以下で実施
することによって、パーライトが微細化され、次いで、
７５容量％以上の水素と残部が実質的に窒素および不可
避的不純物からなるガス雰囲気のベル型バッチ焼鈍炉を
用い、前記（１）〜（９）の焼鈍条件で焼鈍することに
よって、パーライトの形成を防止して短時間でセメンタ
イトを球状化でき、軟質な高炭素冷延鋼帯を得ることが
できる。Thus, C: 0.3-0.8%, S
i: 0.03 to 0.35%, Mn: 0.20 to 1.50
%, The balance being substantially Fe and inevitable impurities, hot rolling, pickling, descaling, and then cold rolling at a rolling reduction of 25% or more and 80% or less. By this, the pearlite is refined,
Using a bell-type batch annealing furnace in a gas atmosphere consisting of 75% by volume or more of hydrogen and the balance substantially consisting of nitrogen and unavoidable impurities, annealing is performed under the annealing conditions (1) to (9) to form pearlite. , Spheroidizing cementite in a short time, and a soft high-carbon cold-rolled steel strip can be obtained.
【００１３】また、本発明の請求項２の高炭素冷延鋼帯
の製造方法は、Ｃ：０．３〜０．８％、Ｓｉ：０．０３
〜０．３５％、Ｍｎ：０．２０〜１．５０％を含有し、
残部が実質的にＦｅおよび不可避的不純物からなる高炭
素鋼片を、熱間圧延、酸洗、脱スケールしたのち、冷間
圧延を圧下率２５％以上８０％以下で実施後、７５容量
％以上の水素と残部が実質的に窒素および不可避的不純
物からなるガス雰囲気のベル型バッチ焼鈍炉を用い、前
記（１）〜（９）の焼鈍条件で一次焼鈍処理したのち、
圧下率２０％以上８０％以下で冷間圧延を行い、ベル型
バッチ焼鈍炉で６００℃〜Ａｃ１点直下で仕上焼鈍を行
うこととしている。The method for producing a high-carbon cold-rolled steel strip according to claim 2 of the present invention is characterized in that: C: 0.3 to 0.8%, Si: 0.03
０．３0.35%, Mn: 0.20 to 1.50%,
After the high-carbon steel slab substantially consisting of Fe and unavoidable impurities is subjected to hot rolling, pickling, and descaling, cold rolling is performed at a rolling reduction of 25% to 80%, and then 75% by volume or more. Using a bell-type batch annealing furnace in a gas atmosphere in which hydrogen and the balance substantially consist of nitrogen and unavoidable impurities, under the annealing conditions (1) to (9),
Cold rolling is performed at a rolling reduction of 20% or more and 80% or less, and finish annealing is performed in a bell-type batch annealing furnace at 600 ° C. to just below Ac1 point.
【００１４】このように、Ｃ：０．３〜０．８％、Ｓ
ｉ：０．０３〜０．３５％、Ｍｎ：０．２０〜１．５０
％を含有し、残部が実質的にＦｅおよび不可避的不純物
からなる高炭素鋼片を、熱間圧延、酸洗、脱スケールし
たのち、冷間圧延を圧下率２５％以上８０％以下で実施
することによって、パーライトが微細化され、次いで、
７５容量％以上の水素と残部が実質的に窒素および不可
避的不純物からなるガス雰囲気のベル型バッチ焼鈍炉を
用い、前記（１）〜（９）の焼鈍条件で一次焼鈍処理す
ることによって、冷却過程におけるパーライトの形成を
防止して短時間でセメンタイトを球状化でき、さらに、
圧下率２０％以上８０％以下で仕上冷間圧延を行い、ベ
ル型バッチ焼鈍炉で６００℃〜Ａｃ１点直下で仕上焼鈍
を行うことによって、冷間圧延歪を開放して結晶粒が成
長し、軟質な高炭素冷延鋼帯を得ることができる。Thus, C: 0.3-0.8%, S
i: 0.03 to 0.35%, Mn: 0.20 to 1.50
%, The balance being substantially Fe and inevitable impurities, hot rolling, pickling, descaling, and then cold rolling at a rolling reduction of 25% or more and 80% or less. By this, the pearlite is refined,
Cooling is performed by performing primary annealing under the above-described annealing conditions (1) to (9) using a bell-type batch annealing furnace in a gas atmosphere consisting of 75% by volume or more of hydrogen and the balance substantially consisting of nitrogen and inevitable impurities. Cementite can be spheroidized in a short time by preventing the formation of pearlite in the process,
The finish cold rolling is performed at a rolling reduction of 20% or more and 80% or less, and the finish annealing is performed in a bell-type batch annealing furnace at a temperature of 600 ° C. to just below Ac1 point, thereby releasing the cold rolling strain and growing crystal grains. A soft high-carbon cold-rolled steel strip can be obtained.
【００１５】さらに、本発明の請求項３の高炭素冷延鋼
帯の製造方法は、請求項１、２で一次焼鈍処理した後、
圧下率２０％以上８５％以下の冷間圧延と、ベル型バッ
チ焼鈍炉での６００℃〜Ａｃ１点直下の仕上焼鈍処理と
を２回以上繰り返すこととしている。このように、一次
焼鈍処理した後、圧下率２０％以上８５％以下の冷間圧
延と、ベル型バッチ焼鈍炉での６００℃〜Ａｃ１点直下
の仕上焼鈍処理とを２回以上繰り返すことによって、セ
メンタイトの球状化率が更に向上してほぼ１００％に近
づき、より軟質な冷延鋼帯を製造可能となり、最終板厚
が薄物、例えば、板厚０．３ｍｍのように１回の冷間圧
延では所望の板厚が得られない場合は、一旦冷間圧延を
中止して仕上焼鈍を同様の条件で行って軟質化した後、
再度冷間圧延を行うことによって所望の板厚となし、再
度仕上焼鈍を同様の条件で行って軟質化することによ
り、板厚０．３ｍｍの軟質な高炭素冷延鋼帯を得ること
ができる。Further, the method for producing a high-carbon cold-rolled steel strip according to claim 3 of the present invention comprises the steps of:
Cold rolling at a rolling reduction of 20% or more and 85% or less and finish annealing at 600 ° C. to just below Ac1 point in a bell-type batch annealing furnace are repeated at least twice. As described above, after the primary annealing treatment, the cold rolling with a reduction ratio of 20% or more and 85% or less and the finish annealing treatment at 600 ° C. to just below Ac1 point in a bell-type batch annealing furnace are repeated twice or more. The spheroidization rate of cementite is further improved and approaches nearly 100%, and a softer cold-rolled steel strip can be manufactured, and the final sheet thickness is thin, for example, one time cold-rolling to a sheet thickness of 0.3 mm. In the case where the desired sheet thickness is not obtained, after the cold rolling is once stopped and the finish annealing is performed under the same conditions to soften,
Cold rolling is again performed to obtain a desired sheet thickness, and finish annealing is performed again under the same conditions to soften the sheet, whereby a soft high-carbon cold-rolled steel strip having a sheet thickness of 0.3 mm can be obtained. .
【００１６】さらにまた、本発明の請求項４の高炭素冷
延鋼帯の製造方法は、Ｃ：０．３〜０．８％、Ｓｉ：
０．０３〜０．３５％、Ｍｎ：０．２０〜１．５０％を
含有し、残部が実質的にＦｅおよび不可避的不純物から
なる高炭素鋼片を、熱間圧延、酸洗、脱スケールしたの
ち、圧下率２５％以上８０％以下の冷間圧延で、かつ鋼
板粗度を中心平均粗さで０．３μｍ以上１．２μｍ以下
を付与した後、７５容量％以上の水素と残部が実質的に
窒素および不可避的不純物からなるガス雰囲気のベル型
バッチ焼鈍炉を用い、前記（１）〜（９）の焼鈍条件で
一次焼鈍処理したのち、伸び率０．６％以上４．０％以
下での調質圧延で、鋼板粗度を０．２μｍ以下に処理す
ることとしている。Further, the method for producing a high-carbon cold-rolled steel strip according to claim 4 of the present invention is characterized in that: C: 0.3 to 0.8%;
A high-carbon steel slab containing 0.03 to 0.35%, Mn: 0.20 to 1.50%, and the balance substantially consisting of Fe and unavoidable impurities is subjected to hot rolling, pickling, and descaling. Then, after cold rolling at a rolling reduction of 25% or more and 80% or less, and a steel sheet roughness of 0.3 μm or more and 1.2 μm or less in center average roughness, hydrogen of 75% by volume or more and the balance Using a bell-type batch annealing furnace in a gas atmosphere consisting of nitrogen and unavoidable impurities, first annealing under the annealing conditions (1) to (9), the elongation is 0.6% or more and 4.0% or less. , The roughness of the steel sheet is reduced to 0.2 μm or less.
【００１７】このように、Ｃ：０．３〜０．８％、Ｓ
ｉ：０．０３〜０．３５％、Ｍｎ：０．２０〜１．５０
％を含有し、残部が実質的にＦｅおよび不可避的不純物
からなる高炭素鋼片を、熱間圧延、酸洗、脱スケールし
たのち、圧下率２５％以上８０％以下の冷間圧延で、か
つ鋼板粗度を中心平均粗さで０．３μｍ以上１．２μｍ
以下を付与した後、７５容量％以上の水素と残部が実質
的に窒素および不可避的不純物からなるガス雰囲気のベ
ル型バッチ焼鈍炉を用い、前記（１）〜（９）の焼鈍条
件で一次焼鈍処理したのち、伸び率０．６％以上４．０
％以下での調質圧延で、鋼板粗度を０．２μｍ以下に処
理することによって、パーライトが微細化されると共
に、鋼板の接触面積が減少して焼鈍時の焼鈍焼付き疵が
防止され、軟質で加工性に優れ、かつ結晶組織の均質性
に優れた高炭素冷延鋼帯を得ることができる。Thus, C: 0.3-0.8%, S
i: 0.03 to 0.35%, Mn: 0.20 to 1.50
%, And the balance is substantially hot-rolled, pickled and descaled from high-carbon steel slabs substantially composed of Fe and unavoidable impurities, and then subjected to cold rolling at a rolling reduction of 25% or more and 80% or less, and Steel plate roughness is 0.3μm or more and 1.2μm in center average roughness
After imparting the following, primary annealing is performed using a bell-type batch annealing furnace in a gas atmosphere consisting of 75% by volume or more of hydrogen and the balance substantially consisting of nitrogen and inevitable impurities under the annealing conditions (1) to (9). After treatment, elongation is 0.6% or more and 4.0
%, By processing the steel plate roughness to 0.2 μm or less by temper rolling at not more than 0.2%, the pearlite is refined, the contact area of the steel plate is reduced, and the annealing seizure flaw at the time of annealing is prevented. A high-carbon cold-rolled steel strip that is soft, has excellent workability, and has excellent crystal structure homogeneity can be obtained.
【００１８】[0018]
【発明の実施の形態】本発明に使用される打抜き性、曲
げ成形性等の塑性加工を前提とする高炭素鋼帯の化学成
分の限定理由は、以下の通りである。BEST MODE FOR CARRYING OUT THE INVENTION The reasons for limiting the chemical composition of a high carbon steel strip used in the present invention, assuming plastic working such as punching properties and bending formability, are as follows.
【００１９】Ｃは、鋼に強度、焼入れ性、耐摩耗性等を
付与する作用を有する元素で、低いほど軟質化して加工
性は良くなるが、０．３％未満では焼入れ性が不足し、
熱処理後に所定の硬度が得られない。一方、０．８％を
超えると熱延鋼帯の段階での硬度が高く、冷間圧延が困
難となるので、０．３〜０．８％とした。C is an element having an effect of imparting strength, hardenability, wear resistance and the like to steel. The lower the C, the softer the workability and the better the workability.
A predetermined hardness cannot be obtained after heat treatment. On the other hand, if it exceeds 0.8%, the hardness at the stage of the hot-rolled steel strip is high, and cold rolling becomes difficult.
【００２０】Ｓｉは、脱酸材として添加する元素である
が、０．０３％未満では脱酸効果が十分ではなく、ま
た、０．３５％を超えると脱酸能力が飽和し、かつ固溶
硬化により素材の成形性を阻害するため、０．０３〜
０．３５％とした。Si is an element to be added as a deoxidizing material, but if it is less than 0.03%, the deoxidizing effect is not sufficient, and if it exceeds 0.35%, the deoxidizing ability is saturated and solid solution 0.03 ~
0.35%.
【００２１】Ｍｎは、強度、焼入れ性を向上させると共
に、セメンタイトの安定化作用を有する元素であるが、
０．２％未満では安定した焼入れ性を確保することがで
きず、また、１．５％を超えると焼入れ性の改善効果が
飽和すると共に、素材の硬度上昇をもたらすので、０．
２〜１．５％とした。Mn is an element which improves the strength and hardenability and has the effect of stabilizing cementite.
If it is less than 0.2%, stable hardenability cannot be secured, and if it exceeds 1.5%, the effect of improving the hardenability is saturated and the hardness of the material is increased.
2 to 1.5%.
【００２２】上記化学組成を有する高炭素鋼片の熱間圧
延は、通常の方法で行われ、熱延条件に特別の制限はな
いが、熱延鋼帯の巻取りは、相変態終了後に行うのが好
ましい。The hot rolling of the high carbon steel slab having the above chemical composition is carried out by a usual method, and there is no particular limitation on the hot rolling conditions, but the winding of the hot rolled steel strip is carried out after the completion of the phase transformation. Is preferred.
【００２３】本発明の請求項１における冷間圧延におけ
る圧下の目的は、パーライトを微細化し、次の焼鈍で球
状化を促進するものであるが、圧下率２５％未満ではパ
ーライトを十分微細化できず、冷間圧延の効果が発揮で
きず、圧下率８０％を超えるとエッジ割れ等の問題を生
じるので、２５〜８０％とした。The purpose of the reduction in the cold rolling in claim 1 of the present invention is to make pearlite finer and to promote spheroidization in the next annealing, but if the rolling reduction is less than 25%, pearlite can be made sufficiently fine. However, the effect of cold rolling cannot be exhibited, and if the rolling reduction exceeds 80%, problems such as edge cracking occur.
【００２４】ベル型バッチ焼鈍炉によるバッチコイル焼
鈍では、最外周の温度と最冷点の温度差が大きく、最冷
点の温度がＡｃ１点以上を確保し、かつ、最外周のＡｃ
１点を超えた均熱温度を８時間以内とするのは困難であ
る。このため、本発明におけるベル型バッチ焼鈍炉での
バッチコイル焼鈍では、表１、図１に示すとおり、温度
０℃、圧力０．１ＭＰａにおいて、熱伝導率が窒素の約
７倍、密度が窒素の約１４倍の水素を、雰囲気ガス中７
５容量％以上とすることによって、コイル幅９６０ｍ
ｍ、コイル外径１８４７ｍｍ、コイル内径６１０ｍｍ、
重量１８Ｔｏｎのコイルを均熱温度７７０℃で焼鈍した
場合の均熱時間とコイル内温度差との関係を示す図２に
示すとおり、コイル内部の熱伝達性が向上し、従来の窒
素を主体とする場合に比較し、コイル内外周の温度差を
小さくすることが可能となり、ベル型バッチ焼鈍炉を適
用することができる。In the case of batch coil annealing using a bell-type batch annealing furnace, the temperature difference between the outermost peripheral temperature and the coldest point is large, and the coldest point temperature is at least Ac1 point.
It is difficult to keep the soaking temperature beyond one point within 8 hours. Therefore, in the batch coil annealing in the bell-type batch annealing furnace according to the present invention, as shown in Table 1 and FIG. 1, at a temperature of 0 ° C. and a pressure of 0.1 MPa, the thermal conductivity is about 7 times that of nitrogen and the density is nitrogen. About 14 times as much hydrogen as
By setting it to 5% by volume or more, the coil width is 960m
m, coil outer diameter 1847 mm, coil inner diameter 610 mm,
As shown in FIG. 2, which shows the relationship between the soaking time and the temperature difference in the coil when the coil having a weight of 18 Ton was annealed at a soaking temperature of 770 ° C., the heat transfer inside the coil was improved, and the conventional nitrogen was mainly used. The temperature difference between the inner and outer peripheries of the coil can be reduced as compared with the case in which a bell-type batch annealing furnace can be applied.
【００２５】[0025]
【表１】 [Table 1]
【００２６】７５容量％以上の水素と残部実質窒素から
なる雰囲気ガス中での焼鈍処理は、図３に示すとおり、
加熱速度２０〜１００℃／ＨｒでＡｃ１点〜Ａｃ１点＋
５０℃に８時間以下均熱したのち、５０℃／Ｈｒ以下で
Ａｒ１点以下まで徐冷する第１段均熱、徐冷工程と、加
熱速度２０〜１００℃でＡｃ１点〜Ａｃ１点＋５０℃に
８Ｈｒ以下均熱したのち、５０℃／Ｈｒ以下でＡｒ１点
以下まで徐冷する第２段均熱、徐冷工程と、以降室温ま
で２０〜１００℃／Ｈｒの速度で冷却する放冷工程とか
らなる。なお、代表的なヒートパターンの一例を図４に
示す。As shown in FIG. 3, the annealing treatment in an atmosphere gas comprising 75% by volume or more of hydrogen and the balance substantially consisting of nitrogen is as follows.
Ac1 point to Ac1 point at heating rate of 20 to 100 ° C / Hr +
After soaking at 50 ° C. for 8 hours or less, the first stage soaking and slow cooling step of gradually cooling to 50 ° C./Hr or less to 1 point or less of Ar and 1 point of Ac to 1 point of Ac + 50 ° C. at a heating rate of 20 to 100 ° C. After soaking for 8 hours or less, the second stage soaking and slow cooling step of gradually cooling to 50 ° C./Hr or less to 1 point Ar or less, and then the cooling step of cooling to room temperature at a rate of 20 to 100 ° C./Hr. Become. FIG. 4 shows an example of a typical heat pattern.
【００２７】上記第１段均熱工程における均熱は、熱延
組織のパーライトをオーステナイト中に固溶させる工程
であり、均熱後の徐冷は、未溶解の残留炭化物を核とす
る固溶Ｃの析出により球状化炭化物を生成させる工程で
ある。加熱速度を２０〜１００℃／Ｈｒとしたのは、２
０℃／Ｈｒ未満では操業効率が悪く、また、１００℃／
Ｈｒを超えると加熱効率が悪くなってコイル内の温度不
均一を生じ易い。均熱温度をＡｃ１点〜Ａｃ１点＋５０
℃としたのは、Ａｃ１点＋５０℃を超えると球状化炭化
物粒形成の核となる未溶解の炭化物を残留させることが
できなくなり、冷却条件を制御してもパーライトが生成
し、また、Ａｃ１点未満ではセメンタイトの球状化に長
時間を要するからである。均熱時間を８時間以下とした
のは、８時間以上の条件では冷却過程にパーライトが生
成する可能性が高いからである。The soaking in the first-stage soaking step is a step in which pearlite having a hot-rolled structure is solid-dissolved in austenite. This is a step of generating spheroidized carbide by precipitation of C. The reason why the heating rate was set to 20 to 100 ° C./Hr is 2
If the temperature is less than 0 ° C / Hr, the operation efficiency is poor, and
If the temperature exceeds Hr, the heating efficiency deteriorates, and the temperature in the coil tends to be uneven. The soaking temperature is from Ac1 point to Ac1 point +50
When the temperature exceeds the Ac1 point + 50 ° C, undissolved carbide serving as nuclei for forming spheroidized carbide grains cannot be left, and pearlite is generated even when the cooling conditions are controlled. If the amount is less than the above, it takes a long time to make the cementite spheroidized. The reason why the soaking time is set to 8 hours or less is that under conditions of 8 hours or more, there is a high possibility that pearlite is generated in the cooling process.
【００２８】第１段均熱後の冷却速度を５０℃／Ｈｒ以
下としたのは、５０℃／Ｈｒを超える冷却速度では固溶
Ｃの析出が抑制されるため、未溶解炭化物を核とする球
状化炭化物の生成が不十分となり、オーステナイトに多
量のＣが固溶したままＡｒ１変態が生起し、層状パーラ
イト組織となってしまうからである。また、冷却到達温
度をＡｒ１点以下としたのは、冷却到達温度がＡｒ１点
を超えると球状化炭化物の生成率が低下するからで、Ａ
ｒ１点より低い温度であればよいが、必要以上に降温さ
せると、それに続く第２段の均熱を行う際の処理効率な
らびに熱経済性の悪化を招くため、Ａｒ１点〜Ａｒ１点
−２０℃で十分である。この第１段均熱、徐冷処理によ
りコイル内の温度は、コイルの中心と外周で球状化率を
低下させない範囲で均一化される。The reason why the cooling rate after the first-stage soaking is set to 50 ° C./Hr or less is that if the cooling rate exceeds 50 ° C./Hr, the precipitation of solid solution C is suppressed, so that undissolved carbides are used as nuclei. This is because the generation of spheroidized carbide becomes insufficient, and the Ar1 transformation occurs while a large amount of C is dissolved in austenite to form a layered pearlite structure. The reason why the cooling temperature is set to the Ar1 point or lower is that if the cooling temperature exceeds the Ar1 point, the generation rate of the spheroidized carbide decreases.
The temperature may be lower than the r1 point, but if the temperature is lowered more than necessary, the processing efficiency and the thermoeconomic efficiency at the time of performing the subsequent second-stage soaking are deteriorated. Is enough. By this first-stage soaking and slow cooling treatment, the temperature in the coil is made uniform within a range where the spheroidization ratio does not decrease at the center and the outer periphery of the coil.
【００２９】上記第２段均熱、徐冷工程における均熱
は、前記第１段均熱、徐冷工程の後更に球状化炭化物の
生成率向上のための処理で、軟質な鋼帯が製造可能とな
る。第２段均熱、徐冷工程における加熱速度、均熱温
度、均熱時間、冷却速度ならびに冷却到達温度を限定し
た理由は、前記第１段均熱、徐冷工程で記載した通りで
ある。The above-mentioned soaking in the second-stage soaking and slow-cooling process is a process for further improving the generation rate of spheroidized carbide after the above-mentioned first-stage soaking and slow-cooling process. It becomes possible. The reason why the heating rate, the soaking temperature, the soaking time, the cooling rate, and the cooling ultimate temperature in the second-stage soaking and slow-cooling steps are limited is as described in the first-stage soaking and slow cooling step.
【００３０】上記第１段ならびに第２段均熱、徐冷工程
後、Ａｒ１点以下から室温までの冷却速度を２０〜１０
０℃／Ｈｒとしたのは、２０℃／Ｈｒ未満では操業効率
が悪く、また、１００℃／Ｈｒを超えるとコイル内外周
の温度差が大きくなり、焼鈍焼付きが多発するからであ
る。After the first and second stage soaking and slow cooling steps, the cooling rate from the Ar 1 point or lower to room temperature is 20 to 10
The reason why the temperature is set to 0 ° C./Hr is that if the temperature is less than 20 ° C./Hr, the operation efficiency is poor, and if the temperature exceeds 100 ° C./Hr, the temperature difference between the inner and outer circumferences of the coil becomes large and annealing seizure frequently occurs.
【００３１】本発明の請求項２においては、前記第１段
ならびに第２段均熱、徐冷工程後、圧下率２０〜８０％
で仕上冷間圧延を行う。仕上冷間圧延の圧下率は、プロ
セス合理化のために圧延機の能力の許す限り大きい方が
好ましいが、軟化の点では冷間圧延の圧下率が２０％付
近にピークがある。圧下率が２０％未満の場合は、結晶
粒の分断が少なく、仕上焼鈍時の粒成長エネルギーが不
足して軟化されない。また、圧下率が８０％を超えた場
合は、結晶粒が小さくなるため、球状化時の炭化物が大
きくならず十分軟化されないため、破断が生じる。その
ため、仕上冷間圧延の圧下率２０％付近で所定の板厚に
なるのであれば、最も軟化した高炭素冷延鋼帯を製造す
ることができる。In the second aspect of the present invention, after the first and second stages of soaking and slow cooling steps, the rolling reduction is 20 to 80%.
Perform finish cold rolling. The rolling reduction in the finish cold rolling is preferably as large as the capacity of the rolling mill permits in order to streamline the process, but in terms of softening, the rolling reduction in the cold rolling has a peak at around 20%. When the rolling reduction is less than 20%, the crystal grains are less fragmented, and are not softened due to insufficient grain growth energy during finish annealing. On the other hand, when the rolling reduction exceeds 80%, the crystal grains become small, so that the carbide at the time of spheroidization does not become large and is not sufficiently softened, so that breakage occurs. Therefore, if the sheet thickness becomes a predetermined value in the vicinity of the rolling reduction of 20% in the finish cold rolling, the softened high carbon cold rolled steel strip can be manufactured.
【００３２】仕上冷間圧延後の仕上焼鈍処理は、一次冷
間圧延、中間焼鈍でセメンタイトの球状化は十分進んで
いるため、仕上焼鈍は冷間圧延後の歪を解消し、結晶粒
が成長すればよいのでＡｃ１点以下でよく、しかも均熱
温度、均熱時間の影響が殆どないので、コイルの最冷点
温度で６００℃以上で１時間あれば十分である。仕上焼
鈍温度は、０．５ｍｍ以下の薄物材をコイル焼鈍すると
焼鈍焼付き疵が発生し、これが製品の光沢度の低下等の
悪影響を及ぼすため、できる限り低い方が望ましいが、
６００℃未満ではフェライトの再結晶、粒成長が不十分
となり、軟質化効果に不足をきたすが、コイルの最冷点
温度で６００℃以上確保すれば、焼鈍焼付き疵を生じる
ことなく軟化焼鈍が可能となる。また、Ａｃ１点を超え
るとオーステナイト相が生成し、冷却過程で層状パーラ
イトが現れて硬質化すると共に、焼付き疵の発生する恐
れがあるからである。In the finish annealing after the finish cold rolling, the spheroidization of the cementite is sufficiently advanced by the primary cold rolling and the intermediate annealing. Therefore, the finish annealing eliminates the strain after the cold rolling, and the crystal grains grow. Therefore, the temperature may be lower than the Ac1 point, and the soaking temperature and the soaking time have almost no influence. The finish annealing temperature is preferably as low as possible because a coiled steel sheet having a thickness of 0.5 mm or less generates annealing seizure flaws, which adversely affects the glossiness of the product.
If the temperature is lower than 600 ° C., recrystallization and grain growth of ferrite become insufficient and the softening effect is insufficient.However, if the coil is maintained at the coldest temperature of 600 ° C. or higher, the softening annealing can be performed without causing the burning seizure flaw. It becomes possible. On the other hand, if it exceeds the Ac1 point, an austenite phase is formed, and layered pearlite appears during the cooling process to become hard, and there is a possibility that seizure flaws may occur.
【００３３】上記仕上焼鈍処理は、前記中間焼鈍処理と
異なり、必ずしも高水素雰囲気とする必要はなく、窒素
主体の雰囲気であってもよい。この仕上焼鈍処理におい
ては、均熱保持時間はそれほど重要ではなく、約１時間
程度の均熱保持時間で十分である。また、冷却速度の制
御は、特に必要はなく、例えば、自然放冷とすることも
できる。Unlike the above-mentioned intermediate annealing, the finish annealing does not necessarily have to be performed in a high hydrogen atmosphere, but may be an atmosphere mainly composed of nitrogen. In this finish annealing treatment, the soaking time is not so important, and a soaking time of about 1 hour is sufficient. Further, the control of the cooling rate is not particularly required, and for example, natural cooling can be performed.
【００３４】上記第１段および第２段均熱、徐冷工程か
らなる中間焼鈍処理後、圧下率２０〜８０％で冷間圧延
を行っても、最終板厚が薄物、例えば、０．３ｍｍ以下
の場合は、１回の冷間圧延では所望の板厚が得られない
場合は、一旦冷間圧延を中止して仕上焼鈍処理を同様の
条件で行って軟質化したのち、再度冷間圧延を行って所
望の板厚となし、仕上焼鈍処理を行う。この仕上冷間圧
延および仕上焼鈍処理は、仕上板厚に応じて複数回実施
することができる。After the intermediate annealing process including the first and second stage soaking and slow cooling steps, even if cold rolling is performed at a rolling reduction of 20 to 80%, the final sheet thickness is small, for example, 0.3 mm. In the following cases, if the desired thickness cannot be obtained by one cold rolling, the cold rolling is temporarily stopped, the finish annealing treatment is performed under the same conditions to soften, and then the cold rolling is performed again. To a desired plate thickness, and a finish annealing treatment is performed. The finish cold rolling and finish annealing can be performed a plurality of times according to the finish plate thickness.
【００３５】本発明の請求項４においては、冷間圧延時
に鋼板粗度を中心線平均粗さ（Ｒａ）で０．３μｍ以上
１．２μｍ以下付与することによって、鋼板の接触面積
を減少し、焼鈍時の焼鈍焼付き防止が可能となる。中心
線平均粗さが０．３μｍ未満では、焼鈍時の焼鈍焼付き
防止効果がなく、また、中心線平均粗さが１．２μｍを
超えると焼鈍後の調質圧延をブライトロールで実施して
も、鋼板粗度が十分に低下せず、ブライトネスを要求さ
れる製品には適用できないためである。In the fourth aspect of the present invention, the contact area of the steel sheet is reduced by providing the steel sheet with a center line average roughness (Ra) of 0.3 μm or more and 1.2 μm or less during cold rolling. Prevention of seizure during annealing becomes possible. When the center line average roughness is less than 0.3 μm, there is no effect of preventing the seizure during annealing, and when the center line average roughness exceeds 1.2 μm, the temper rolling after annealing is performed with a bright roll. This is because the steel sheet roughness does not sufficiently decrease and cannot be applied to products requiring brightness.
【００３６】本発明の請求項４における鋼板粗度を中心
線平均粗さ０．３μｍ以上１．２μｍ以下付与した後の
調質圧延は、冷間圧延時に焼鈍時の焼鈍焼付き防止のた
め付与された中心線平均粗さ０．３μｍ以上１．２μｍ
以下の鋼板粗度を整えることを主目的とし、最終製品粗
度が中心線平均粗さで０．２０μｍ以下となるよう伸び
率０．６％以上４．０％以下で実施する。調質圧延時の
伸び率が０．６％未満では、最終製品粗度が中心線平均
粗さで０．２０μｍ以下を確保することができず、ま
た、伸び率が４．０％超では、最終製品粗度が中心線平
均粗さで０．２０μｍ以下を確保できるが、鋼板硬度が
高くなり、本来の目的とする軟質鋼板の製造ができな
い。In the fourth aspect of the present invention, the temper rolling after imparting the roughness of the steel sheet with a center line average roughness of 0.3 μm or more and 1.2 μm or less is performed in order to prevent seizure during annealing during cold rolling. Center line average roughness 0.3 μm or more and 1.2 μm
The main purpose is to adjust the following steel plate roughness, and the elongation is 0.6% or more and 4.0% or less so that the final product roughness is 0.20 μm or less in center line average roughness. If the elongation percentage during temper rolling is less than 0.6%, the final product roughness cannot secure a center line average roughness of 0.20 μm or less, and if the elongation percentage exceeds 4.0%, Although the final product roughness can secure a center line average roughness of 0.20 μm or less, the hardness of the steel sheet becomes high, and the original intended soft steel sheet cannot be manufactured.
【００３７】[0037]
実施例１ 表２に示す化学組成の鋼Ｎｏ．１〜４の高炭素鋼片を、
仕上板厚２ｍｍ、仕上温度８４０℃、巻取温度６５０℃
の熱延条件で熱間圧延して高炭素熱延鋼帯となし、酸
洗、脱スケールしたのち、圧下率７０％で冷間圧延を行
い、水素９９容量％、残部窒素からなるガス雰囲気のベ
ル型バッチ焼鈍炉を用いて、表３に示す試験Ｎｏ．１〜
２５の第１〜第２段均熱、徐冷工程からなる一次焼鈍処
理を行い、高炭素冷延鋼帯を得た。各高炭素冷延鋼帯か
ら試験片を切り出し、ＪＩＳ Ｚ２２４４に規定のビッ
カース硬さ試験方法に準じてビッカース硬さ（ＨＶ）を
測定し、各高炭素冷延鋼帯の鋼種毎に、ＪＩＳ Ｇ ３
３１１に規定のみがき特殊帯鋼に規定される焼なまし後
のビッカース硬さと比較した軟質度（表４参照）で評価
した。Example 1 Steel No. 1 having the chemical composition shown in Table 2 1 to 4 high carbon steel slabs
Finish plate thickness 2mm, Finish temperature 840 ° C, Winding temperature 650 ° C
After hot rolling under hot rolling conditions to form a high carbon hot rolled steel strip, pickling and descaling, cold rolling is performed at a rolling reduction of 70%, and a gas atmosphere consisting of 99% by volume of hydrogen and the balance of nitrogen Using a bell-type batch annealing furnace, test Nos. 1 to
A first annealing treatment comprising 25 first and second-stage soaking and slow cooling steps was performed to obtain a high-carbon cold-rolled steel strip. A test piece was cut out from each high-carbon cold-rolled steel strip, and Vickers hardness (HV) was measured according to the Vickers hardness test method specified in JIS Z2244. 3
Evaluation was made based on the softness (see Table 4) in comparison with the Vickers hardness after annealing specified for the special steel strip specified in 311.
【００３８】[0038]
【表２】 [Table 2]
【００３９】[0039]
【表３】 [Table 3]
【００４０】[0040]
【表４】 [Table 4]
【００４１】表３に示すとおり、一次焼鈍処理における
均熱温度がＡｃ１点未満の試験Ｎｏ．２の高炭素冷延鋼
帯は、ビッカース硬度ＨＶ：１８０となり、軟質化が十
分でない。一次焼鈍処理における各段の均熱温度がＡｃ
１点＋５０℃を超える試験Ｎｏ．５、１７の高炭素冷延
鋼帯は、ビッカース硬度ＨＶ：１９２、１６６と硬質で
ある。一次焼鈍処理における各段の均熱時間が８時間を
超える試験Ｎｏ．９、２１の高炭素冷延鋼帯は、ビッカ
ース硬度ＨＶ：１９８、１７９と硬質である。一次焼鈍
処理における冷却速度が５０℃／Ｈｒを超える試験Ｎ
ｏ．１１、２３の高炭素冷延鋼帯も硬質である。一次焼
鈍処理における冷却到達温度がＡｒ１点以上の試験Ｎ
ｏ．１２、２４の高炭素冷延鋼帯も、ビッカース硬度Ｈ
Ｖ：１７６、１８９と硬質である。As shown in Table 3, in test No. 1 in which the soaking temperature in the primary annealing treatment was less than the Ac1 point. The high-carbon cold-rolled steel strip No. 2 has a Vickers hardness HV: 180 and is not sufficiently softened. The soaking temperature of each stage in the primary annealing process is Ac
Test No. exceeding 1 point + 50 ° C The high carbon cold rolled steel strips Nos. 5 and 17 are hard with Vickers hardness HV: 192, 166. Test No. 1 in which the soaking time of each stage in the primary annealing treatment exceeded 8 hours. The high carbon cold-rolled steel strips of Nos. 9 and 21 are hard with Vickers hardness HV: 198, 179. Test N in which cooling rate in primary annealing exceeds 50 ° C / Hr
o. The high-carbon cold-rolled steel strips 11 and 23 are also hard. Test N in which the ultimate cooling temperature in the primary annealing treatment is Ar 1 point or more
o. 12, 24 high carbon cold rolled steel strips also have Vickers hardness H
V: Hard as 176, 189.
【００４２】これに対し、一次焼鈍処理における各段の
均熱温度がＡｃ１点〜Ａｃ１＋５０℃、各段の均熱時間
が８時間以内、冷却速度が５０℃／Ｈｒ以下、冷却到達
温度がＡｒ１点直下と本発明条件を満足させる試験Ｎ
ｏ．１、３、４、６〜８、１０、１４〜１６、１８〜２
０、２２および２５の高炭素冷延鋼帯は、表３に示すと
おり、いずれもビッカース硬度（ＨＶ）が標準よりも軟
質である。また、表３に示すとおり、試験Ｎｏ．２６の
ように一次焼鈍処理における各段の加熱速度、冷却速度
が５℃／Ｈｒ、３℃／Ｈｒでも高炭素冷延鋼帯の硬度に
は悪影響を及ぼさないが、焼鈍処理の生産効率の面なら
びに省エネルギーの面でのメリットはない。On the other hand, in the primary annealing treatment, the soaking temperature of each stage is from Ac1 point to Ac1 + 50 ° C., the soaking time of each stage is within 8 hours, the cooling rate is 50 ° C./Hr or less, and the cooling temperature is Ar1 point. Test N that satisfies the conditions of the present invention immediately below
o. 1, 3, 4, 6-8, 10, 14-16, 18-2
As shown in Table 3, the high-carbon cold-rolled steel strips of 0, 22, and 25 all have a Vickers hardness (HV) that is softer than the standard. In addition, as shown in Table 3, Test No. Although the heating rate and cooling rate of each stage in the primary annealing treatment at 5 ° C./Hr and 3 ° C./Hr do not adversely affect the hardness of the high-carbon cold-rolled steel strip as shown in FIG. There is no merit in energy saving.
【００４３】実施例２ 前記表２に示す化学組成の鋼Ｎｏ．１〜４の高炭素鋼片
を、仕上板厚：２ｍｍ、仕上温度：８４０℃、巻取温
度：６５０℃の熱延条件で熱間圧延して高炭素熱延鋼帯
となし、酸洗、脱スケールしたのち、圧下率５０％で中
間冷間圧延を行い、次いで水素９９容量％、残部窒素か
らなるガス雰囲気のベル型バッチ焼鈍炉を用い、表５に
示す試験Ｎｏ．２６〜５０の第１〜第２段均熱、徐冷工
程からなる一次焼鈍処理を行った。次に圧下率２０％で
冷間圧延したのち、水素９９容量％、残部窒素からなる
ガス雰囲気のベル型バッチ焼鈍炉を用い、均熱温度：６
００℃、均熱時間：１時間の仕上焼鈍処理を施し、高炭
素冷延鋼帯を得た。得られた各高炭素冷延鋼帯から試験
片を切り出し、ＪＩＳ Ｚ ２２４４に規定のビッカー
ス硬さ試験方法に準じてビッカース硬さ（ＨＶ）を測定
し、各高炭素冷延鋼帯の鋼種毎に、ＪＩＳ Ｇ ３３１
１に規定のみがき特殊帯鋼に規定される焼なまし後のビ
ッカース硬さと比較した軟質度（表４参照）で評価し
た。その結果を表５に示す。Example 2 Steel No. 1 having the chemical composition shown in Table 2 above was used. The high carbon steel slabs of Nos. 1-4 are hot-rolled under hot rolling conditions of a finishing plate thickness: 2 mm, a finishing temperature: 840 ° C, and a winding temperature: 650 ° C to form a high-carbon hot-rolled steel strip, pickling, After descaling, intermediate cold rolling was performed at a rolling reduction of 50%. Then, using a bell-type batch annealing furnace in a gas atmosphere consisting of 99% by volume of hydrogen and the balance of nitrogen, test Nos. A primary annealing treatment consisting of 26 to 50 first and second stage soaking and slow cooling steps was performed. Next, after cold rolling at a rolling reduction of 20%, a bell-type batch annealing furnace in a gas atmosphere consisting of 99% by volume of hydrogen and the balance of nitrogen was used, and a soaking temperature: 6
A finish annealing treatment at 00 ° C. and soaking time of 1 hour was performed to obtain a high carbon cold-rolled steel strip. A test piece was cut out from each of the obtained high-carbon cold-rolled steel strips, and the Vickers hardness (HV) was measured according to the Vickers hardness test method specified in JIS Z 2244. And JIS G 331
Evaluation was made based on the softness (see Table 4) in comparison with the Vickers hardness after annealing specified for the special steel strip specified in Example 1. Table 5 shows the results.
【００４４】[0044]
【表５】 [Table 5]
【００４５】表５に示すとおり、一次焼鈍処理における
均熱温度がＡｃ１点未満の試験Ｎｏ．２７の高炭素冷延
鋼帯は、ビッカース硬度ＨＶ：１７４となり、軟質化が
十分でない。一次焼鈍処理における各段の均熱温度がＡ
ｃ１点＋５０℃を超える試験Ｎｏ．３０、４１の高炭素
冷延鋼帯は、ビッカース硬度ＨＶ：１８８、１６０と硬
質である。一次焼鈍処理における各段の均熱時間が８時
間を超える試験Ｎｏ．３４、４５の高炭素冷延鋼帯は、
ビッカース硬度ＨＶ：１９５、１７４と硬質である。一
次焼鈍処理における冷却速度が５０℃／Ｈｒを超える試
験Ｎｏ．３６、４７の高炭素冷延鋼帯も硬質である。一
次焼鈍処理における冷却到達温度がＡｒ１点以上の試験
Ｎｏ．３７、４８の高炭素冷延鋼帯も、ビッカース硬度
ＨＶ：１７１、１８０と硬質である。As shown in Table 5, in Test No. 1 in which the soaking temperature in the primary annealing treatment was less than the Ac1 point. The 27 high-carbon cold-rolled steel strip has a Vickers hardness HV of 174 and is not sufficiently softened. The soaking temperature of each stage in the primary annealing process is A
Test no. The high carbon cold rolled steel strips 30 and 41 are hard with Vickers hardness HV: 188 and 160. Test No. 1 in which the soaking time of each stage in the primary annealing treatment exceeded 8 hours. 34, 45 high carbon cold rolled steel strip
Vickers hardness HV is as high as 195 and 174. Test No. 1 in which the cooling rate in the primary annealing treatment exceeded 50 ° C./Hr. The high carbon cold rolled steel strips 36 and 47 are also hard. Test No. in which the ultimate cooling temperature in the primary annealing treatment was Ar 1 point or more. The high carbon cold rolled steel strips of 37 and 48 are also hard with Vickers hardness HV: 171 and 180.
【００４６】これに対し、一次焼鈍処理における各段の
均熱温度がＡｃ１点〜Ａｃ１点＋５０℃、各段の均熱時
間が８時間以内、冷却速度が５０℃／Ｈｒ以下、冷却到
達温度がＡｒ１点直下と本発明条件を満足させる試験Ｎ
ｏ．２６、２８、２９、３１〜３３、３５、３８〜４
０、４２〜４４、４６および４９の高炭素冷延鋼帯は、
表５に示すとおり、いずれもビッカース硬度（ＨＶ）が
標準よりも軟質である。また、表５に示すとおり、試験
Ｎｏ．５０のように一次焼鈍処理における各段の加熱速
度、冷却速度が５℃／Ｈｒ、３℃／Ｈｒでも高炭素冷延
鋼帯の硬度には悪影響を及ぼさないが、焼鈍処理の生産
効率の面ならびに省エネルギーの面でのメリットはな
い。On the other hand, in the primary annealing treatment, the soaking temperature of each stage is from Ac1 point to Ac1 point + 50 ° C., the soaking time of each stage is within 8 hours, the cooling rate is 50 ° C./Hr or less, and the cooling ultimate temperature is Test N that satisfies the conditions of the present invention just below Ar1 point
o. 26, 28, 29, 31-33, 35, 38-4
0,42-44,46 and 49 high carbon cold rolled steel strip
As shown in Table 5, Vickers hardness (HV) is softer than the standard. In addition, as shown in Table 5, Test No. Even if the heating rate and cooling rate of each stage in the primary annealing treatment are 5 ° C./Hr and 3 ° C./Hr as in 50, the hardness of the high carbon cold rolled steel strip is not adversely affected, but the production efficiency of the annealing treatment is reduced. There is no merit in energy saving.
【００４７】実施例３ 鋼中の化学成分の影響を調査すべく、表６に示す鋼Ｎ
ｏ．５〜１４の各高炭素鋼片を、仕上板厚：２ｍｍ、仕
上温度：８４０℃、巻取温度６５０℃の熱延条件で熱間
圧延して高炭素熱延鋼帯となし、各高炭素熱延鋼帯を酸
洗、脱スケール処理したのち、圧下率７０％で冷間圧延
を実施後、水素９９容量％、残部窒素からなるガス雰囲
気のベル型バッチ焼鈍炉を用い、加熱速度：５０℃／Ｈ
ｒ、第１段均熱温度：７４０℃、第１段均熱時間：４Ｈ
ｒ、第１段均熱完了後の冷却速度１０℃／Ｈｒで６６０
℃まで冷却後、加熱速度：５０℃／Ｈｒ、第２段均熱温
度：Ａｃ１点＋２０℃、第２段均熱時間：５時間、第２
段均熱完了後の冷却速度３０℃／Ｈｒ、冷却到達温度：
Ａｒ１点−１０℃の第２段均熱、徐冷を行って一次焼鈍
処理を行った。得られた各高炭素冷延鋼帯から試験片を
採取し、実施例１と同様にＪＩＳ Ｚ ２２４４に規定
のビッカース硬さ試験方法に準じてビッカース硬さを測
定した。その結果を表６に示す。Example 3 In order to investigate the influence of chemical components in steel, steel N shown in Table 6 was used.
o. Each high carbon steel slab of 5 to 14 was hot-rolled under hot rolling conditions of a finishing plate thickness: 2 mm, a finishing temperature: 840 ° C, and a winding temperature of 650 ° C to form a high-carbon hot-rolled steel strip. After pickling and descaling the hot-rolled steel strip, cold rolling was performed at a rolling reduction of 70%, and a bell-type batch annealing furnace in a gas atmosphere consisting of 99% by volume of hydrogen and the balance of nitrogen was used. ° C / H
r, first-stage soaking temperature: 740 ° C, first-stage soaking time: 4H
r, 660 at a cooling rate of 10 ° C./Hr after completion of the first-stage soaking
After cooling to 0 ° C., heating rate: 50 ° C./Hr, second-stage soaking temperature: Ac 1 point + 20 ° C., second-stage soaking time: 5 hours, second
Cooling rate after completion of stage soaking: 30 ° C / Hr, ultimate cooling temperature:
The first annealing treatment was performed by performing a second-stage soaking at an Ar point of −10 ° C. and slow cooling. A test piece was collected from each of the obtained high-carbon cold-rolled steel strips, and the Vickers hardness was measured in the same manner as in Example 1 according to the Vickers hardness test method specified in JIS Z 2244. Table 6 shows the results.
【００４８】[0048]
【表６】 [Table 6]
【００４９】表６に示すとおり、本発明の範囲外である
鋼Ｎｏ．１０、１４の高炭素冷延鋼帯は、それぞれＳ
ｉ、Ｍｎの添加量が本発明範囲の上限を超えるため、他
の本発明に該当する鋼帯に比べ硬質である。また、鋼Ｎ
ｏ．７、１１の高炭素冷延鋼帯は、Ｓｉ、Ｍｎの添加量
が本発明範囲の下限を下回るため、軟質となっている。
鋼Ｎｏ．７の高炭素冷延鋼帯では、Ｓｉ含有率が低いた
め、焼入れ、焼戻し後の疲労強度において酸化物の増大
による特性劣化の危険性を伴う。また、鋼Ｎｏ．１１の
高炭素冷延鋼帯では、Ｍｎ含有率が低いため、焼入れ性
が低下し、焼入れ、焼戻し後、十分な硬度が得られない
危険性がある。As shown in Table 6, the steel Nos. 10 and 14 high carbon cold rolled steel strips
Since the addition amounts of i and Mn exceed the upper limit of the range of the present invention, the steel strip is harder than other steel strips corresponding to the present invention. In addition, steel N
o. The high-carbon cold-rolled steel strips Nos. 7 and 11 are soft because the addition amounts of Si and Mn are below the lower limit of the range of the present invention.
Steel No. In the high carbon cold rolled steel strip of No. 7, since the Si content is low, there is a risk of deterioration of characteristics due to an increase in oxides in fatigue strength after quenching and tempering. In addition, steel No. In the high-carbon cold-rolled steel strip of No. 11, since the Mn content is low, the quenchability decreases, and there is a risk that sufficient hardness cannot be obtained after quenching and tempering.
【００５０】実施例４ 一次焼鈍処理後の冷間圧延における圧下率と、冷間圧延
後の仕上焼鈍における均熱温度の影響を調査するため、
前記表６に示す鋼Ｎｏ．１２の高炭素鋼片を、仕上板
厚：２ｍｍ、仕上温度：８４０℃、巻取温度６５０℃の
熱延条件で熱間圧延して高炭素熱延鋼帯となし、酸洗、
脱スケール処理したのち、圧下率４０％で中間冷間圧延
を実施後、水素９９容量％、残部窒素からなるガス雰囲
気のベル型バッチ焼鈍炉を用い、加熱速度：５０℃／Ｈ
ｒ、第１段均熱温度：Ａｃ１点＋３０℃、第１段均熱時
間：４時間、第１段均熱後の冷却速度：４０℃／Ｈｒ、
第１段冷却時の冷却到達温度：Ａｒ１点−１０℃の第１
段の均熱、徐冷後、加熱速度：１０℃／Ｈｒ、第２段均
熱温度：Ａｃ１点＋２０℃、第２段均熱時間：４時間、
第２段均熱後の冷却速度：１０℃／Ｈｒ、第２段冷却時
の冷却到達温度：Ａｒ１点の第２段均熱、徐冷を行って
一次焼鈍処理を施した。次いで圧下率を表７に示すとお
り２０〜８５％の範囲で変化させて仕上冷間圧延したの
ち、水素９９容量％、残部窒素からなるガス雰囲気のベ
ル型バッチ焼鈍炉を用い、均熱温度：６００℃〜７２０
℃、仕上焼鈍時間１時間および５時間の仕上焼鈍処理を
施して高炭素冷延鋼帯を得た。得られた各高炭素冷延鋼
帯から試験片を採取し、実施例１と同様にＪＩＳ Ｚ
２２４４に規定のビッカース硬さ試験方法に準じてビッ
カース硬さ（ＨＶ）を測定した。その結果を表７に示
す。Example 4 In order to investigate the effects of the rolling reduction in the cold rolling after the primary annealing and the soaking temperature in the finish annealing after the cold rolling,
The steel No. shown in Table 6 above. No. 12 high-carbon steel slab was hot-rolled under hot-rolling conditions of a finishing plate thickness of 2 mm, a finishing temperature of 840 ° C., and a winding temperature of 650 ° C. to form a high-carbon hot-rolled steel strip, pickling,
After the descaling treatment, intermediate cold rolling was performed at a rolling reduction of 40%, and a bell-type batch annealing furnace in a gas atmosphere consisting of 99% by volume of hydrogen and the balance of nitrogen was used, and the heating rate was 50 ° C / H.
r, first-stage soaking temperature: Ac 1 point + 30 ° C., first-stage soaking time: 4 hours, cooling rate after first-stage soaking: 40 ° C./Hr,
Ultimate cooling temperature during first stage cooling: Ar 1 point-1st of -10 ° C
After soaking and slow cooling of the stage, heating rate: 10 ° C./Hr, soaking temperature of the second stage: Ac 1 point + 20 ° C., soaking time of the second stage: 4 hours,
The cooling rate after the second-stage soaking: 10 ° C./Hr, the ultimate cooling temperature during the second-stage cooling: the second-stage soaking at one Ar point, and the slow annealing were performed to perform the primary annealing treatment. Then, after the finish cold-rolling with the rolling reduction changed in the range of 20 to 85% as shown in Table 7, a bell-type batch annealing furnace in a gas atmosphere consisting of 99% by volume of hydrogen and the balance of nitrogen was used. 600 ° C ~ 720
A high-carbon cold-rolled steel strip was obtained by performing a final annealing treatment at 1 ° C. and a final annealing time of 1 hour and 5 hours. A test piece was collected from each of the obtained high-carbon cold-rolled steel strips and was subjected to JIS Z in the same manner as in Example 1.
Vickers hardness (HV) was measured according to the Vickers hardness test method specified in 2244. Table 7 shows the results.
【００５１】[0051]
【表７】 [Table 7]
【００５２】表７に示すとおり、仕上冷間圧延における
圧下率が２０％の試験Ｎｏ．５１からも明らかなとお
り、圧下率が２０％未満では結晶粒が異常粒成長を生じ
るため、伸びが低下することを示している。また、仕上
冷間圧延における圧下率が８５％の試験Ｎｏ．５５で
は、冷間圧延中に破断を生じた。このことから、仕上冷
間圧延における圧下率は、２０〜８０％に限定される。
さらに、仕上焼鈍の均熱温度が５９０℃の試験Ｎｏ．５
６では、硬度が高くなっている。このことから、仕上焼
鈍の均熱温度は、６００℃以上が必要である。これに対
し、この発明の条件を満足させる試験Ｎｏ．５２〜５
４、５７〜５９では、硬度ＨＶが満足すべきものが得ら
れている。また、試験Ｎｏ．６０の結果からは、仕上焼
鈍の均熱時間が１時間でも十分に軟質化していることが
わかる。[0052] As shown in Table 7, in test cold rolling with a rolling reduction of 20% in the finish cold rolling. As is clear from FIG. 51, when the rolling reduction is less than 20%, abnormal growth of crystal grains occurs, and thus the elongation decreases. Test No. with a rolling reduction of 85% in the finish cold rolling. At 55, fracture occurred during cold rolling. For this reason, the rolling reduction in the finish cold rolling is limited to 20 to 80%.
Further, in Test No. in which the soaking temperature of the finish annealing was 590 ° C. 5
In No. 6, the hardness is high. For this reason, the soaking temperature of the finish annealing needs to be 600 ° C. or higher. On the other hand, Test No. 3 satisfying the conditions of the present invention. 52-5
Nos. 4, 57 to 59 have satisfactory hardness HV. Test No. From the result of No. 60, it can be seen that the soaking time of the finish annealing was sufficiently softened even for one hour.
【００５３】実施例５ 前記実施例３の表６中の鋼Ｎｏ．９の高炭素鋼片を、仕
上板厚：２ｍｍ、仕上温度：８４０℃、巻取温度６５０
℃の熱延条件で熱間圧延して高炭素熱延鋼帯となし、酸
洗、脱スケール処理したのち、圧下率６０％（仕上板厚
０．８ｍｍ）で表８に示す鋼板粗度を付与しつつ冷間圧
延を施し、水素９９容量％、残部窒素からなるガス雰囲
気のベル型バッチ焼鈍炉を用い、第１段均熱温度までの
加熱速度：５０℃／Ｈｒ、第１段均熱温度：７４０℃、
第１段均熱時間：４時間、第１段均熱完了後の冷却速
度：１０℃／Ｈｒで６６０℃まで冷却後、第２段均熱温
度までの加熱速度：５０℃／Ｈｒ、第２段均熱温度：Ａ
ｃ１＋２０℃、第２段均熱時間：５時間、第２段均熱完
了後の冷却速度：３０℃／Ｈｒ、第２段冷却完了時の冷
却到達温度：Ａｒ１−１０℃の仕上焼鈍処理を行った。
次いで、表８に示すロール粗度のワークロールを用い、
表８に示す伸び率で調質圧延を施し、高炭素冷延鋼帯を
得た。なお、表８中の粗度は、中心線平均粗さ（Ｒａ）
で示し、粗度評価はブライトネス確保の点より、粗度≦
０．２０μｍを可（○）とした。Example 5 Steel No. 3 in Table 6 of Example 3 was used. 9 high carbon steel slab, finishing plate thickness: 2 mm, finishing temperature: 840 ° C, winding temperature 650
After hot-rolling under hot-rolling conditions of 0 ° C. to form a high-carbon hot-rolled steel strip, pickling and descaling, the steel sheet roughness shown in Table 8 at a rolling reduction of 60% (finished sheet thickness 0.8 mm) was obtained. Cold-rolled while applying, using a bell-type batch annealing furnace in a gas atmosphere consisting of 99% by volume of hydrogen and the balance of nitrogen, heating rate up to first-stage soaking temperature: 50 ° C / Hr, first-stage soaking Temperature: 740 ° C,
First-stage soaking time: 4 hours, Cooling rate after completion of first-stage soaking: After cooling to 660 ° C at 10 ° C / Hr, heating rate to second-stage soaking temperature: 50 ° C / Hr, second Step soaking temperature: A
c1 + 20 ° C., second-stage soaking time: 5 hours, cooling rate after completion of second-stage soaking: 30 ° C./Hr, ultimate cooling temperature after completion of second-stage cooling: Ar1-10 ° C. Was.
Next, using a work roll having a roll roughness shown in Table 8,
Temper rolling was performed at an elongation percentage shown in Table 8 to obtain a high-carbon cold-rolled steel strip. The roughness in Table 8 is the center line average roughness (Ra)
, The roughness evaluation, from the point of ensuring brightness, roughness ≦
0.20 μm was considered acceptable (可).
【００５４】[0054]
【表８】 [Table 8]
【００５５】表８に示すとおり、試験Ｎｏ．６１におい
て冷間圧延後の鋼板粗度が０．２μｍでは、最終製品粗
度は満たすものの、焼鈍処理時に焼付きが発生し、製品
とはならない。そこで、試験Ｎｏ．６２以降に示すよう
に、冷間圧延後の鋼板粗度が０．３μｍ以上必要とな
る。試験Ｎｏ．６４、６６の調質圧延時の伸び率が０．
６％未満では、冷間圧延時の鋼板粗度を調整しても、最
終製品粗度を満たさない。試験Ｎｏ．６７、６８の調質
圧延時のロール粗度が０．１μｍを超えると他の条件を
調整しても、最終製品粗度を満たさない。試験Ｎｏ．６
２、６３、６５に示すように冷間圧延後の鋼板粗度が
０．３〜１．２μｍ、調質圧延時のロール粗度が０．１
μｍ以下、調質圧延時の伸び率が０．６〜２．０％を満
たすことで、焼鈍処理時に焼付き発生がなく、最終製品
粗度０．２０μｍ以下の製品を得ることができる。As shown in Table 8, Test No. In 61, when the roughness of the steel sheet after cold rolling is 0.2 μm, the roughness of the final product is satisfied, but seizure occurs during the annealing treatment, and the product does not become a product. Therefore, the test No. As shown after 62, the steel plate after cold rolling must have a roughness of 0.3 μm or more. Test No. The elongation at the time of temper rolling of 64, 66 is 0.
If it is less than 6%, the final product roughness will not be satisfied even if the steel sheet roughness during cold rolling is adjusted. Test No. If the roll roughness at the time of temper rolling of 67 and 68 exceeds 0.1 μm, the final product roughness will not be satisfied even if other conditions are adjusted. Test No. 6
As shown in 2, 63 and 65, the steel plate roughness after cold rolling is 0.3 to 1.2 μm, and the roll roughness during temper rolling is 0.1.
When the elongation at the time of temper rolling satisfies 0.6 to 2.0%, seizure does not occur during the annealing treatment, and a product having a final product roughness of 0.20 μm or less can be obtained.
【００５６】実施例６ 冷間圧延における圧下率を明確にするため、表６に示す
鋼Ｎｏ．１２（Ｓ５５ＣＭ）の高炭素熱延鋼帯を用い
て、表９に示す圧下率で冷間圧延した後、表３の試験Ｎ
ｏ．１３の焼鈍条件で焼鈍処理を実施し、高炭素冷延鋼
帯を得た。得られた各高炭素冷延鋼帯から試験片を切り
出し、ＪＩＳ Ｚ ２２４４に規定のビッカース硬さ試
験方法に準じてビッカース硬さ（ＨＶ）を測定し、各高
炭素冷延鋼帯毎に、ＪＩＳ Ｇ ３３１１に規定のみが
き特殊帯鋼に規定される焼なまし後のビッカース硬さと
比較した軟質度（表４参照）で評価した。その結果を表
９に示す。Example 6 In order to clarify the rolling reduction in cold rolling, steel No. 1 shown in Table 6 was used. 12 (S55CM) using a high-carbon hot-rolled steel strip, cold-rolled at a rolling reduction shown in Table 9, and then tested in Table 3
o. Annealing was performed under the annealing conditions of No. 13 to obtain a high-carbon cold-rolled steel strip. A test piece was cut out from each of the obtained high-carbon cold-rolled steel strips, and Vickers hardness (HV) was measured according to the Vickers hardness test method specified in JIS Z 2244. The evaluation was made based on the softness (see Table 4) in comparison with the Vickers hardness after annealing specified in JIS G 3311 as a special steel strip. Table 9 shows the results.
【００５７】[0057]
【表９】 [Table 9]
【００５８】表９に示すとおり、試験Ｎｏ．７１のよう
に冷間圧延における圧下率は、８０％以下が適正値であ
る。As shown in Table 9, Test No. As for 71, the rolling reduction in the cold rolling is an appropriate value of 80% or less.
【００５９】[0059]
【発明の効果】本発明の請求項１の高炭素冷延鋼帯の製
造方法は、高炭素熱延鋼帯を圧下率２５％以上８０％以
下で冷間圧延を行い、７５容量％以上の水素と残部が実
質的に窒素および不可避的不純物からなるガス雰囲気の
ベル型バッチ焼鈍炉を用い、２０〜１００℃／Ｈｒの加
熱速度でＡｃ１点〜Ａｃ１点＋５０℃に加熱して８時間
以下均熱保持後、５０℃／Ｈｒ以下の冷却速度でＡｒ１
点以下まで冷却する均熱、徐冷を２回繰り返すことによ
って、冷却過程におけるパーライトの生成を防止して短
時間でセメンタイトを球状化でき、軟質な高炭素冷延鋼
帯を得ることができる。According to the method for producing a high-carbon cold-rolled steel strip according to the first aspect of the present invention, the high-carbon hot-rolled steel strip is subjected to cold rolling at a rolling reduction of 25% or more and 80% or less, and 75% by volume or more. Using a bell-type batch annealing furnace in a gas atmosphere in which hydrogen and the balance substantially consist of nitrogen and unavoidable impurities, heat at a heating rate of 20 to 100 ° C./Hr to Ac1 point to Ac1 point + 50 ° C. and average for 8 hours or less. After heat holding, Ar1 was cooled at a cooling rate of 50 ° C./Hr or less.
By repeating soaking and gradual cooling twice below the point, generation of pearlite in the cooling process can be prevented, cementite can be spheroidized in a short time, and a soft high-carbon cold-rolled steel strip can be obtained.
【００６０】本発明の請求項２の高炭素冷延鋼帯の製造
方法は、高炭素熱延鋼帯を圧下率２５％以上８０％以下
で冷間圧延を実施後、７５容量％以上の水素と残部が実
質的に窒素および不可避的不純物からなるガス雰囲気の
ベル型バッチ焼鈍炉を用い、２０〜１００℃／Ｈｒの加
熱速度でＡｃ１点〜Ａｃ１点＋５０℃に加熱して８時間
以下均熱保持後、５０℃／Ｈｒ以下の冷却速度でＡｒ１
点以下まで冷却する均熱、徐冷を２回繰り返して一次焼
鈍処理したのち、圧下率２０％以上８０％以下で冷間圧
延を行い、ベル型バッチ焼鈍炉で６００℃〜Ａｃ１点直
下で仕上焼鈍を行うことによって、球状化の完了した軟
質な冷延鋼帯を所定板厚となし、冷間圧延歪を開放して
結晶粒が成長し、軟質な高炭素冷延鋼帯を得ることがで
きる。In the method for producing a high-carbon cold-rolled steel strip according to a second aspect of the present invention, the high-carbon hot-rolled steel strip is subjected to cold rolling at a rolling reduction of 25% or more and 80% or less and then 75% by volume or more of hydrogen. A bell-type batch annealing furnace having a gas atmosphere substantially consisting of nitrogen and unavoidable impurities, and heating at a heating rate of 20 to 100 ° C./Hr to Ac1 point to Ac1 point + 50 ° C. and soaking for 8 hours or less After the holding, Ar1 was cooled at a cooling rate of 50 ° C./Hr or less.
After performing primary annealing by repeating soaking and gradual cooling twice to a temperature below the point, cold rolling is performed at a rolling reduction of 20% or more and 80% or less, and finishing is performed in a bell-type batch annealing furnace at 600 ° C to just below Ac1 point. By performing the annealing, the spheroidized soft cold-rolled steel strip is made to have a predetermined thickness, the cold-rolling strain is released, and the crystal grains grow to obtain a soft high-carbon cold-rolled steel strip. it can.
【００６１】本発明の請求項３の高炭素冷延鋼帯の製造
方法は、高炭素熱延鋼帯を圧下率２５％以上８０％以下
で冷間圧延を実施後、７５容量％以上の水素と残部が実
質的に窒素および不可避的不純物からなるガス雰囲気の
ベル型バッチ焼鈍炉を用い、２０〜１００℃／Ｈｒの加
熱速度でＡｃ１点〜Ａｃ１点＋５０℃に加熱して８時間
以下均熱保持後、５０℃／Ｈｒ以下の冷却速度でＡｒ１
点以下まで冷却する均熱、徐冷を２回繰り返して一次焼
鈍処理したのち、圧下率２０％以上８０％以下の冷間圧
延と、ベル型バッチ焼鈍炉での６００℃〜Ａｃ１点直下
の仕上焼鈍とを２回以上繰り返すことによって、軟質な
板厚０．３ｍｍ以下の極薄高炭素冷延鋼帯を得ることが
できる。According to a third aspect of the present invention, there is provided a method for producing a high-carbon cold-rolled steel strip, wherein the high-carbon hot-rolled steel strip is cold-rolled at a rolling reduction of 25% or more and 80% or less, and then 75% by volume or more of hydrogen. A bell-type batch annealing furnace having a gas atmosphere substantially consisting of nitrogen and unavoidable impurities, and heating at a heating rate of 20 to 100 ° C./Hr to Ac1 point to Ac1 point + 50 ° C. and soaking for 8 hours or less After the holding, Ar1 was cooled at a cooling rate of 50 ° C./Hr or less.
After the primary annealing treatment by repeating soaking and gradual cooling twice to a temperature below the point, cold rolling at a rolling reduction of 20% or more and 80% or less, and finishing in a bell-type batch annealing furnace at 600 ° C. to just below the Ac1 point. By repeating annealing twice or more, a soft ultra-thin high-carbon cold-rolled steel strip having a thickness of 0.3 mm or less can be obtained.
【００６２】本発明の請求項４の高炭素冷延鋼帯の製造
方法は、高炭素熱延鋼帯を圧下率２０％以上８５％以下
で鋼板粗度０．３〜１．２μｍを付与しつつ冷間圧延を
実施後、７５容量％以上の水素と残部が実質的に窒素お
よび不可避的不純物からなるガス雰囲気のベル型バッチ
焼鈍炉を用い、２０〜１００℃／Ｈｒの加熱速度でＡｃ
１点〜Ａｃ１点＋５０℃に加熱して８時間以下均熱保持
後、５０℃／Ｈｒ以下の冷却速度でＡｒ１点以下まで冷
却する均熱、徐冷を２回繰り返して焼鈍処理したのち、
伸び率０．６〜２．０％で調質圧延することによって、
中間焼鈍時においても、焼鈍焼付きの発生なく、最終製
品粗度０．２０μｍ以下の軟質な高炭素冷延鋼帯を得る
ことができる。The method for producing a high-carbon cold-rolled steel strip according to claim 4 of the present invention is characterized in that a high-carbon hot-rolled steel strip is provided with a steel sheet roughness of 0.3 to 1.2 μm at a rolling reduction of 20% to 85%. After performing cold rolling while performing cold rolling, Ac was applied at a heating rate of 20 to 100 ° C./Hr using a bell-type batch annealing furnace in a gas atmosphere consisting of 75% by volume or more of hydrogen and the balance substantially consisting of nitrogen and unavoidable impurities.
After heating to 1 point to Ac1 point + 50 ° C and maintaining the soaking temperature for 8 hours or less, annealing and cooling are repeated twice, that is, soaking and cooling at a cooling rate of 50 ° C / Hr or less to 1 point or less of Ar.
By temper rolling at an elongation of 0.6 to 2.0%,
Even during intermediate annealing, a soft high-carbon cold-rolled steel strip having a final product roughness of 0.20 μm or less can be obtained without occurrence of annealing seizure.
【図１】温度４００℃、６００℃、８００℃における水
素濃度と熱伝導率との関係を示すグラフである。FIG. 1 is a graph showing a relationship between hydrogen concentration and thermal conductivity at temperatures of 400 ° C., 600 ° C., and 800 ° C.
【図２】水素：７５％、残部窒素からなる雰囲気ガスと
水素５％、残部窒素からなる雰囲気ガスの雰囲気温度で
の均熱時間とコイル内温度差との関係を示すグラフであ
る。FIG. 2 is a graph showing a relationship between a soaking time at an atmospheric temperature of an atmosphere gas consisting of 75% of hydrogen and the balance of nitrogen and an atmosphere gas consisting of 5% of hydrogen and a balance of nitrogen, and a temperature difference in a coil.
【図３】本発明の第１段均熱、第２段均熱、徐冷工程か
らなる焼鈍処理のヒートパターンを示すグラフである。FIG. 3 is a graph showing a heat pattern of an annealing treatment including a first-stage soaking, a second-stage soaking, and a slow cooling process according to the present invention.
【図４】本発明の第１段均熱、第２段均熱、徐冷工程か
らなる焼鈍処理の代表的なヒートパターンの一例を示す
グラフである。FIG. 4 is a graph showing an example of a typical heat pattern of an annealing process including a first-stage soaking, a second-stage soaking, and a slow cooling process of the present invention.
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.6 識別記号 ＦＩ Ｃ２２Ｃ 38/04 Ｃ２２Ｃ 38/04 ──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. 6 Identification code FI C22C 38/04 C22C 38/04
Claims (4)
〜０．３５％、Ｍｎ：０．２０〜１．５０％を含有し、
残部が実質的にＦｅおよび不可避的不純物からなる高炭
素鋼片を、熱間圧延、酸洗、脱スケールしたのち、圧下
率２５％以上８０％以下で冷間圧延を実施後、７５容量
％以上の水素と残部が実質的に窒素および不可避的不純
物からなるガス雰囲気のベル型バッチ焼鈍炉を用い、下
記（１）〜（９）の焼鈍条件で焼鈍することを特徴とす
る高炭素冷延鋼帯の製造方法。 （１） 第１段均熱温度までの加熱速度：２０℃／Ｈｒ
〜１００℃／Ｈｒ （２） 第１段均熱温度×時間：Ａｃ１点〜Ａｃ１点＋
５０℃×８Ｈｒ以下 （３） 第１段均熱完了後の冷却速度：５０℃／Ｈｒ以
下 （４） 第１段冷却完了時の冷却到達温度：Ａｒ１点以
下 （５） 第２段均熱温度までの加熱速度：２０℃／Ｈｒ
〜１００℃／Ｈｒ （６） 第２段均熱温度×時間：Ａｃ１点〜Ａｃ１点＋
５０℃×８Ｈｒ以下 （７） 第２段均熱完了後の冷却速度：５０℃／Ｈｒ以
下 （８） 第２段冷却完了時の冷却到達温度：Ａｒ１点以
下 （９） 以降は２０℃／Ｈｒ〜１００℃／Ｈｒで室温ま
で冷却1. C: 0.3-0.8%, Si: 0.03
０．３0.35%, Mn: 0.20 to 1.50%,
After the high carbon steel slab substantially consisting of Fe and unavoidable impurities is subjected to hot rolling, pickling, and descaling, and then cold rolling at a rolling reduction of 25% or more and 80% or less, then 75% by volume or more. A high-carbon cold-rolled steel characterized by being annealed under the following annealing conditions (1) to (9) using a bell-type batch annealing furnace in a gas atmosphere consisting essentially of nitrogen and unavoidable impurities. The production method of the belt. (1) Heating rate up to the first stage soaking temperature: 20 ° C / Hr
１００100 ° C./Hr (2) First-stage soaking temperature × time: Ac1 point to Ac1 point +
(3) Cooling rate after completion of first-stage soaking: 50 ° C / Hr or less (4) Ultimate cooling temperature after completion of first-stage cooling: Ar1 point or less (5) Second-stage soaking temperature Heating rate up to: 20 ° C / Hr
１００100 ° C./Hr (6) Second stage soaking temperature × time: Ac1 point to Ac1 point +
(7) Cooling rate after completion of second-stage soaking: 50 ° C / Hr or less (8) Ultimate cooling temperature after completion of second-stage cooling: Ar 1 point or less (9) After that, 20 ° C / Hr Cool to room temperature at ~ 100 ° C / Hr
〜０．３５％、Ｍｎ：０．２０〜１．５０％を含有し、
残部が実質的にＦｅおよび不可避的不純物からなる高炭
素鋼片を、熱間圧延、酸洗、脱スケールしたのち、冷間
圧延を圧下率２５％以上８０％以下で実施後、７５容量
％以上の水素と残部が実質的に窒素および不可避的不純
物からなるガス雰囲気のベル型バッチ焼鈍炉を用い、下
記（１）〜（９）の焼鈍条件で一次焼鈍処理したのち、
圧下率２０％以上８０％以下で冷間圧延を行い、ベル型
バッチ焼鈍炉で６００℃〜Ａｃ１点直下で仕上焼鈍を行
うことを特徴とする高炭素冷延鋼帯の製造方法。 （１） 第１段均熱温度までの加熱速度：２０℃／Ｈｒ
〜１００℃／Ｈｒ （２） 第１段均熱温度×時間：Ａｃ１点〜Ａｃ１点＋
５０℃×８Ｈｒ以下 （３） 第１段均熱完了後の冷却速度：５０℃／Ｈｒ以
下 （４） 第１段冷却完了時の冷却到達温度：Ａｒ１点以
下 （５） 第２段均熱温度までの加熱速度：２０℃／Ｈｒ
〜１００℃／Ｈｒ （６） 第２段均熱温度×時間：Ａｃ１点〜Ａｃ１点＋
５０℃×８Ｈｒ以下 （７） 第２段均熱完了後の冷却速度：５０℃／Ｈｒ以
下 （８） 第２段冷却完了時の冷却到達温度：Ａｒ１点以
下 （９） 以降は２０℃／Ｈｒ〜１００℃／Ｈｒで室温ま
で冷却2. C: 0.3-0.8%, Si: 0.03
０．３0.35%, Mn: 0.20 to 1.50%,
After the high-carbon steel slab substantially consisting of Fe and unavoidable impurities is subjected to hot rolling, pickling, and descaling, cold rolling is performed at a rolling reduction of 25% to 80%, and then 75% by volume or more. After performing primary annealing under the following annealing conditions (1) to (9) using a bell-type batch annealing furnace in a gas atmosphere in which hydrogen and the balance substantially consist of nitrogen and inevitable impurities,
A method for producing a high-carbon cold-rolled steel strip, comprising: performing cold rolling at a rolling reduction of 20% or more and 80% or less, and performing finish annealing in a bell-type batch annealing furnace at a temperature of 600 ° C. to just below Ac1 point. (1) Heating rate up to the first stage soaking temperature: 20 ° C / Hr
１００100 ° C./Hr (2) First-stage soaking temperature × time: Ac1 point to Ac1 point +
(3) Cooling rate after completion of first-stage soaking: 50 ° C / Hr or less (4) Ultimate cooling temperature after completion of first-stage cooling: Ar1 point or less (5) Second-stage soaking temperature Heating rate up to: 20 ° C / Hr
１００100 ° C./Hr (6) Second stage soaking temperature × time: Ac1 point to Ac1 point +
(7) Cooling rate after completion of second-stage soaking: 50 ° C / Hr or less (8) Ultimate cooling temperature after completion of second-stage cooling: Ar 1 point or less (9) After that, 20 ° C / Hr Cool to room temperature at ~ 100 ° C / Hr
８０％以下の冷間圧延と、ベル型バッチ焼鈍炉での６０
０℃〜Ａｃ１点直下の仕上焼鈍とを２回以上繰り返すこ
とを特徴とする請求項１または２記載の高炭素冷延鋼帯
の製造方法。3. After the primary annealing treatment, cold rolling at a rolling reduction of 20% or more and 80% or less and 60% in a bell-type batch annealing furnace.
The method for producing a high-carbon cold-rolled steel strip according to claim 1 or 2, wherein the finish annealing at 0 ° C to just below the Ac1 point is repeated at least twice.
〜０．３５％、Ｍｎ：０．２０〜１．５０％を含有し、
残部が実質的にＦｅおよび不可避的不純物からなる高炭
素鋼片を、熱間圧延、酸洗、脱スケールしたのち、圧下
率２５％以上８０％以下の冷間圧延で、かつ鋼板粗度を
中心平均粗さで０．３μｍ以上１．２μｍ以下を付与し
た後、７５容量％以上の水素と残部が実質的に窒素およ
び不可避的不純物からなるガス雰囲気のベル型バッチ焼
鈍炉を用い、下記（１）〜（９）の焼鈍条件で一次焼鈍
処理したのち、伸び率０．６％以上４．０％以下での調
質圧延で、鋼板粗度を０．２μｍ以下とすることを特徴
とする高炭素冷延鋼帯の製造方法。 （１） 第１段均熱温度までの加熱速度：２０℃／Ｈｒ
〜１００℃／Ｈｒ （２） 第１段均熱温度×時間：Ａｃ１点〜Ａｃ１点＋
５０℃×８Ｈｒ以下 （３） 第１段均熱完了後の冷却速度：５０℃／Ｈｒ以
下 （４） 第１段冷却完了時の冷却到達温度：Ａｒ１点以
下 （５） 第２段均熱温度までの加熱速度：２０℃／Ｈｒ
〜１００℃／Ｈｒ （６） 第２段均熱温度×時間：Ａｃ１点〜Ａｃ１点＋
５０℃×８Ｈｒ以下 （７） 第２段均熱完了後の冷却速度：５０℃／Ｈｒ以
下 （８） 第２段冷却完了時の冷却到達温度：Ａｒ１点以
下 （９） 以降は２０℃／Ｈｒ〜１００℃／Ｈｒで室温ま
で冷却4. C: 0.3-0.8%, Si: 0.03
０．３0.35%, Mn: 0.20 to 1.50%,
The high-carbon steel slab substantially consisting of Fe and unavoidable impurities is hot-rolled, pickled, and descaled, and then cold-rolled at a rolling reduction of 25% or more and 80% or less, and the center of the steel sheet roughness is measured. After imparting an average roughness of 0.3 μm or more and 1.2 μm or less, using a bell-type batch annealing furnace in a gas atmosphere consisting of 75% by volume or more of hydrogen and the balance substantially consisting of nitrogen and unavoidable impurities, the following (1) )-Primary annealing under the annealing conditions of (9), followed by temper rolling at an elongation of 0.6% or more and 4.0% or less, to make the steel sheet roughness 0.2 μm or less. Manufacturing method of carbon cold rolled steel strip. (1) Heating rate up to the first stage soaking temperature: 20 ° C / Hr
１００100 ° C./Hr (2) First-stage soaking temperature × time: Ac1 point to Ac1 point +
(3) Cooling rate after completion of first-stage soaking: 50 ° C / Hr or less (4) Ultimate cooling temperature after completion of first-stage cooling: Ar1 point or less (5) Second-stage soaking temperature Heating rate up to: 20 ° C / Hr
１００100 ° C./Hr (6) Second stage soaking temperature × time: Ac1 point to Ac1 point +
(7) Cooling rate after completion of second-stage soaking: 50 ° C / Hr or less (8) Ultimate cooling temperature after completion of second-stage cooling: Ar 1 point or less (9) After that, 20 ° C / Hr Cool to room temperature at ~ 100 ° C / Hr
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1737697A JPH10204540A (en) | 1997-01-14 | 1997-01-14 | Production of cold rolled high-carbon steel strip |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1737697A JPH10204540A (en) | 1997-01-14 | 1997-01-14 | Production of cold rolled high-carbon steel strip |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH10204540A true JPH10204540A (en) | 1998-08-04 |
Family
ID=11942301
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1737697A Pending JPH10204540A (en) | 1997-01-14 | 1997-01-14 | Production of cold rolled high-carbon steel strip |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH10204540A (en) |
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| JP2014177691A (en) * | 2013-03-15 | 2014-09-25 | Kobe Steel Ltd | Method of producing steel material excellent in cold workability and grindability |
| JP2015094005A (en) * | 2013-11-12 | 2015-05-18 | 株式会社神戸製鋼所 | Spheroidizing heat treatment method for alloy steel |
| CN104313297A (en) * | 2014-11-10 | 2015-01-28 | 芜湖双源管业有限公司 | Waste heat recycling method for cold-rolled strip annealing furnace |
| WO2020202641A1 (en) * | 2019-03-29 | 2020-10-08 | 日本製鉄株式会社 | High-carbon steel sheet and method for manufacturing same |
| JP2020164939A (en) * | 2019-03-29 | 2020-10-08 | 日鉄日新製鋼株式会社 | High carbon steel sheet and method for producing the same |
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| WO2022209306A1 (en) | 2021-04-02 | 2022-10-06 | 日本製鉄株式会社 | Steel sheet and method for producing same |
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