JP3291188B2 - Manufacturing method of steel sheet with excellent toughness - Google Patents
Manufacturing method of steel sheet with excellent toughnessInfo
- Publication number
- JP3291188B2 JP3291188B2 JP34613095A JP34613095A JP3291188B2 JP 3291188 B2 JP3291188 B2 JP 3291188B2 JP 34613095 A JP34613095 A JP 34613095A JP 34613095 A JP34613095 A JP 34613095A JP 3291188 B2 JP3291188 B2 JP 3291188B2
- Authority
- JP
- Japan
- Prior art keywords
- rolling
- peripheral speed
- shape ratio
- average temperature
- bite
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
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- Control Of Metal Rolling (AREA)
- Heat Treatment Of Steel (AREA)
- Heat Treatment Of Strip Materials And Filament Materials (AREA)
Description
【0001】[0001]
【発明の属する技術分野】本発明は形状が良好で靱性が
優れた鋼板を製造する方法に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a steel sheet having a good shape and excellent toughness.
【0002】[0002]
【従来の技術】低温での靱性に優れた鋼板を得るため、
制御圧延方法が広く使用されるようになって来ている。
この制御圧延方法は圧延中の圧延温度を精度良く制御
し、最終圧延仕上がり温度をAr 3温度直上にするもの
であり、これによりミクロ組織を微細化させ、靱性の大
幅な改善を図ることができる。2. Description of the Related Art In order to obtain a steel sheet having excellent toughness at low temperatures,
Controlled rolling methods are becoming widely used.
This controlled rolling method accurately controls the rolling temperature during rolling.
And the final rolling finish temperature is Ar ThreeThings just above the temperature
This makes the microstructure finer and increases toughness.
Wide improvement can be achieved.
【0003】従来の制御圧延方法は図1に圧延中の鋼板
の温度推移を示す如く、製品板厚tに対し、所定の厚み
で一旦一次圧延(粗圧延)作業を中止し、その後の空冷
により、その時の温度T1 から目標とする所定の温度T
2 まで冷却した後に二次圧延(仕上圧延)を行い、製品
板厚tとなる時の最終圧延時の仕上がり温度がAr 3温
度直上にするように制御していた(特開昭50−984
21号公報)。[0003] The conventional controlled rolling method is shown in FIG.
As shown in the figure, a predetermined thickness with respect to the product thickness t
To temporarily stop the primary rolling (rough rolling) work and then air-cool
From the temperature T1 at that time, the target temperature T
After secondary cooling (finish rolling), the product
The finishing temperature at the time of final rolling when the plate thickness becomes t is Ar ThreeWarm
(See Japanese Patent Application Laid-Open No. 50-984).
No. 21).
【0004】しかし、この特開昭50−98421号公
報の制御圧延は通常圧延とは異なり、圧延の途中におい
て圧延作業を一旦停止し、鋼材の温度が図1のようにT
1 からT2 になるまで空冷により冷却するので、冷却に
長時間を有する事から圧延能率が低下して生産性が低く
なると共に靱性も低いものであった。However, the control rolling disclosed in Japanese Patent Application Laid-Open No. 50-98421 is different from the normal rolling, and the rolling operation is temporarily stopped during the rolling, and the temperature of the steel material is reduced to T as shown in FIG.
Since cooling was performed by air cooling from 1 to T2, the cooling time was long, so that the rolling efficiency was reduced, the productivity was lowered, and the toughness was low.
【0005】このため、特開昭60−56017号公報
で提案の様に、前記鋼材の圧延途中での冷却を冷却水に
よる強制冷却として、冷却時間を短縮することにより前
記生産性を向上すると共に靱性の向上を図る方法があ
る。[0005] Therefore, as proposed in Japanese Patent Application Laid-Open No. 60-56017, the cooling during the rolling of the steel material is forcibly cooled with cooling water, thereby shortening the cooling time and improving the productivity. There is a method for improving toughness.
【0006】しかし、この冷却水を使用した強制冷却は
冷却停止温度によっては鋼材の長手方向、幅方向に均一
に冷却することが難しく、鋼材に温度ムラが発生し、こ
の温度ムラにより二次圧延時に反りが発生し易く、この
反りのため圧延作業を一旦中断して反りを矯正した後に
再度圧延をしたり、又、圧延作業を中止しなければなら
なく場合が発生して、圧延効率が悪く生産性を阻害した
り、手間のかかる圧延作業となり作業性が悪いという問
題を有していた。However, in the forced cooling using the cooling water, it is difficult to uniformly cool the steel material in the longitudinal direction and the width direction depending on the cooling stop temperature, and the temperature of the steel material becomes uneven. Warpage is likely to occur at times, and the rolling operation is temporarily interrupted for this warpage to correct the warpage and then roll again, or the rolling operation must be stopped, and the rolling efficiency is poor. There was a problem that productivity was hindered, and the rolling work was troublesome, resulting in poor workability.
【0007】[0007]
【発明が解決しようとする課題】本発明は上記問題を有
することなく、靱性の優れた鋼板を生産性よく、しか
も、反りの発生のない良好な形状を維持しつつ圧延する
ことを課題とするものである。SUMMARY OF THE INVENTION An object of the present invention is to roll a steel sheet having excellent toughness without the above-mentioned problems, with good productivity and while maintaining a good shape without warpage. Things.
【0008】[0008]
【課題を解決するための手段】本発明は上記した課題を
達成するため、以下に示す事項を手段とする。 (1)850℃以上で一次圧延を終了した板厚40mm
以上の鋼材を強制冷却し、その後、二次圧延を行って7
20〜850℃で該圧延を終了することにより靱性の優
れた鋼板を製造する方法において、前記二次圧延を行う
際、該圧延の各パス毎の鋼材の噛込入射角と圧延形状比
を予測し、その予測した噛込入射角と圧延形状比から下
記〜のいずれに該当するかを判定し、この判定した
〜の上ワークロールと下ワークロールの周速の関係
となるように、前記二次圧延を行う二次圧延機の各パス
毎の上ワークロールと下ワークロールの周速を調整する
ことを特徴とする靱性の優れた鋼板の製造方法 噛込入射角<0°、圧延形状比>1.5の場合 上ロール周速<下ロール周速 噛込入射角>0°、圧延形状比>1.5の場合上ロール周速>下ロール周速 噛込入射角<0°、圧延形状比<1.5の場合上ロール周速<下ロール周速 噛込入射角>0°、圧延形状比<1.5の場合上ロール周速>下ロール周速 但し、圧延形状比=(接触投影孤長/平均板厚) (2)850℃以上で一次圧延を終了した板厚40mm
以上の鋼材を強制冷却し、その後、二次圧延を行って7
20〜850℃で該圧延を終了することにより靱性の優
れた鋼板を製造する方法において、前記二次圧延を行う
際、該圧延の各パス毎の鋼材の噛込入射角と圧延形状比
を予測し、その予測した噛込入射角と圧延形状比から下
記〜のいずれに該当するかを判定し、この判定した
〜の鋼材の上面と下面の平均温度との関係となるよ
うに、前記鋼材の上、下面の強制冷却量を調整すること
を特徴とする靱性の優れた鋼板の製造方法 噛込入射角<0°、圧延形状比>1.5の場合 上面の平均温度>下面の平均温度 噛込入射角>0°、圧延形状比>1.5の場合 上面の平均温度<下面の平均温度 噛込入射角<0°、圧延形状比<1.5の場合 上面の平均温度<下面の平均温度 噛込入射角>0°、圧延形状比<1.5の場合 上面の平均温度>下面の平均温度 但し、圧延形状比=(接触投影孤長/平均板厚) (3)850℃以上で一次圧延を終了した板厚40mm
以上の鋼材を強制冷却し、その後、二次圧延を行って7
20〜850℃で該圧延を終了することにより靱性の優
れた鋼板を製造する方法において、前記二次圧延を行う
際、該圧延の各パス毎の鋼材の噛込入射角と圧延形状比
を予測し、その予測した噛込入射角と圧延形状比から下
記〜のいずれに該当するかを判定し、この判定した
〜の鋼材の上面と下面の平均温度、上ワークロール
と下ワークロールの周速の関係となるように、前記鋼材
の上、下面の強制冷却量及び鋼材噛み込み前の前記二次
圧延機のの各パス毎の上ワークロールと下ワークロール
の周速を各々調整することを特徴とする靱性の優れた鋼
板の製造方法 噛込入射角<0°、圧延形状比>1.5の場合 上面の平均温度>下面の平均温度で、且つ、上ロール周
速<下ロール周速 噛込入射角>0°、圧延形状比>1.5の場合 上面の平均温度<下面の平均温度で、且つ、上ロール周
速>下ロール周速 噛込入射角<0°、圧延形状比<1.5の場合 上面の平均温度<下面の平均温度で、且つ、上ロール周
速<下ロール周速 噛込入射角>0°、圧延形状比<1.5の場合 上面の平均温度>下面の平均温度で、且つ、上ロール周
速>下ロール周速 但し、圧延形状比=(接触投影孤長/平均板厚) 一次圧延と二次圧延の途中で鋼材を冷却水で強制冷却す
ると図2の製造行程の差による熱履歴の差を示す図の様
に破線部分の板厚方向の平均冷却速度が速くなり、高温
滞留時間が大幅に短縮する。この為、図3に示すように
圧延途中で空冷した場合(圧延途中の冷却以外は同一製
造条件)に比較して、靱性がvTrsで約−30℃改善
される。Means for Solving the Problems In order to achieve the above object, the present invention uses the following items. (1) 40 mm thick after primary rolling at 850 ° C or higher
The above steel material was forcibly cooled, and then subjected to secondary rolling to obtain 7
In the method for producing a steel sheet having excellent toughness by terminating the rolling at 20 to 850 ° C., when the secondary rolling is performed, the bite incidence angle and rolling shape ratio of the steel for each pass of the rolling are predicted. Then, it is determined from the predicted bite incidence angle and the rolling shape ratio whether any of the following applies to the following, and the above-mentioned two are determined so as to have a relationship between the determined peripheral speeds of the upper work roll and the lower work roll. Method for producing steel sheet with excellent toughness characterized by adjusting the peripheral speeds of the upper work roll and the lower work roll for each pass of the secondary rolling mill for performing the next rolling. > 1.5 upper roll peripheral speed <lower roll peripheral speed biting incident angle> 0 °, rolling shape ratio> 1.5 upper roll peripheral speed> lower roll peripheral speed biting incident angle <0 °, rolling shape ratio <case on a roll peripheral speed of 1.5 <lower roll peripheral speed bite incident angle> 0 °, rolling shape ratio If the roll peripheral speed of 1.5> lower roll peripheral speed, however, rolling shape ratio = (contact projection arc length / average thickness) (2) thickness 40mm completing the primary rolling at 850 ° C. or higher
The above steel material was forcibly cooled, and then subjected to secondary rolling to obtain 7
In the method for producing a steel sheet having excellent toughness by terminating the rolling at 20 to 850 ° C., when the secondary rolling is performed, the bite incidence angle and rolling shape ratio of the steel for each pass of the rolling are predicted. Then, from the predicted bite incidence angle and the rolling shape ratio, it is determined which one of the following applies, and the steel material of the steel material is so determined as to have a relationship between the average temperature of the upper surface and the lower surface of the determined steel material. Method for producing a steel sheet having excellent toughness characterized by adjusting the amount of forced cooling of the upper and lower surfaces. In the case of bite incidence angle <0 °, rolling shape ratio> 1.5 Average temperature of upper surface> Average temperature of lower surface When the incident angle> 0 ° and the rolling shape ratio> 1.5, the average temperature of the upper surface <the average temperature of the lower surface When the incident angle <0 ° and the rolling shape ratio <1.5, the average temperature of the upper surface <the average of the lower surface Temperature In the case of bite incidence angle> 0 ° and rolling shape ratio <1.5 Average temperature of upper surface> Average of lower surface Temperature However, rolling shape ratio = (contact projection arc length / average plate thickness) (3) Plate thickness 40 mm after primary rolling at 850 ° C. or more
The above steel material was forcibly cooled, and then subjected to secondary rolling to obtain 7
In the method for producing a steel sheet having excellent toughness by terminating the rolling at 20 to 850 ° C., when the secondary rolling is performed, the bite incidence angle and rolling shape ratio of the steel for each pass of the rolling are predicted. From the predicted bite incidence angle and the rolling shape ratio, it is determined which of the following applies: the average temperature of the upper surface and the lower surface of the determined steel material, the peripheral speed of the upper work roll and the lower work roll. So that the peripheral speed of the upper work roll and the peripheral speed of the lower work roll for each pass of the secondary rolling mill before the bite of the steel material and the forced cooling of the lower surface of the steel material are adjusted. Manufacturing method of steel sheet with excellent toughness In case of bite incident angle <0 °, rolling shape ratio> 1.5 Average temperature of upper surface> Average temperature of lower surface, and upper roll peripheral speed <lower roll peripheral speed In the case of biting incidence angle> 0 ° and rolling shape ratio> 1.5 Average of upper surface Degrees <on the lower surface of the average temperature, and the upper roll peripheral speed> lower roll peripheral speed bite angle of incidence <0 °, the average temperature of the average temperature <lower surface of the upper surface when the rolling shape ratio <1.5, and, above Roll circumference
Speed <lower roll peripheral speed bite incidence angle> 0 °, rolling shape ratio <1.5 Average temperature of upper surface> average temperature of lower surface and upper roll circumference
Speed> lower roll peripheral speed, where rolling shape ratio = (contact projection arc length / average plate thickness) When the steel material is forcibly cooled with cooling water during the primary rolling and the secondary rolling, the heat history due to the difference in the manufacturing process shown in FIG. As shown in the figure showing the difference, the average cooling rate in the thickness direction of the broken line portion is increased, and the high-temperature residence time is significantly reduced. Therefore, as shown in FIG. 3, the toughness is improved by about −30 ° C. in vTrs as compared with the case where air cooling is performed during rolling (the same manufacturing conditions except for cooling during rolling).
【0009】しかしながら、このように一次圧延の後に
強制冷却を実施して再び二次圧延を行って鋼板を製造す
る方法においては鋼材を長手方向、幅方向に均一に冷却
する事が非常に難しく、この温度差が引金となって強制
冷却後の二次圧延時に反りが発生する事から、該強制冷
却後における二次圧延で鋼材の形状を良好(反りの無い
状態)に確保することは二次圧延中に反り修正作業を未
然に防ぎ、反り修正等のロスタイムを発生させることな
く圧延作業を完逐する上で重要である。However, in the method of manufacturing a steel sheet by performing forced cooling after primary rolling and then performing secondary rolling again as described above, it is extremely difficult to uniformly cool the steel material in the longitudinal and width directions. Since this temperature difference triggers warpage during secondary rolling after forced cooling, it is difficult to ensure the shape of the steel material in a good state (a state without warpage) by secondary rolling after forced cooling. It is important to prevent warpage correction work before the next rolling and to complete the rolling work without causing loss time such as warpage correction.
【0010】そこで、強制冷却後の二次圧延の条件を検
討するために、種々の鋼材厚、鋼材幅に対して圧延条件
(噛込入射角、圧延形状比=接触孤長/平均板厚、上下
ロール周速)、上下面の温度差を変化させて、二次圧延
中の圧延材の反りの状況を調査した結果をそれぞれ図
4、図5に示す。Therefore, in order to examine the conditions of the secondary rolling after the forced cooling, rolling conditions (mesh incident angle, rolling shape ratio = contact arc length / average plate thickness, FIGS. 4 and 5 show the results of examining the state of warpage of the rolled material during the secondary rolling while changing the temperature difference between the upper and lower rolls and the upper and lower surfaces.
【0011】尚、上記接触投影孤長はThe contact projection length is
【0012】[0012]
【数1】 で求めた値である。(Equation 1) Is the value obtained in
【0013】又、噛込入射角は図6に示す角度αであ
り、具体的には圧延機側面から直接カメラにより観察
し、それを画像解析して求めたものである。The bite incidence angle is the angle α shown in FIG. 6, and is specifically obtained by observing the image directly from the side of the rolling mill with a camera and analyzing the image.
【0014】上記図4(1)から上ロール周速>下ロー
ル周速で圧延形状比>1.5の場合は上反りとなり、圧
延形状比<1.5の場合は下反りとなり、図4(2)か
ら上ロール周速<下ロール周速で圧延形状比>1.5の
場合は下反りとなり、逆に、圧延形状比<1.5の場合
は下反りとなることが判明した。From FIG. 4 (1), when the upper roll peripheral speed> the lower roll peripheral speed and the rolling shape ratio> 1.5, the warpage occurs, and when the rolling shape ratio <1.5, the warpage occurs. From (2), it was found that when the upper roll peripheral speed <the lower roll peripheral speed and the rolling shape ratio> 1.5, the warpage was downward, and conversely, when the rolling shape ratio <1.5, the warpage was downward.
【0015】また、図4(3)から噛込入射角<0で圧
延形状比>1.5の場合は上反りとなり、圧延形状比<
1.5の場合は下反りとなり、図4(4)から噛込入射
角>0°で圧延形状比>1.5の場合は下反りとなり、
圧延形状比<1.5の場合は上反りとなることが判明し
た。From FIG. 4 (3), when the angle of incidence is <0 and the rolling shape ratio is> 1.5, warpage occurs, and the rolling shape ratio <
In the case of 1.5, warpage occurs, and from FIG. 4 (4), in the case of a bite incidence angle> 0 ° and a rolling shape ratio> 1.5, warpage occurs.
It was found that when the rolling shape ratio was less than 1.5, warpage occurred.
【0016】このことから、噛込入射角<0°、圧延
形状比>1.5の場合には、このままでは上反りとなる
ため、上ロール周速<下ロール周速とすれば、この上反
りが防止でき、噛込入射角>0°、圧延形状比>1.
5の場合には、このままでは下反りとなるため、上ロー
ル周速>下ロール周速とすることにより、この下反りを
防止できることを見出した。From the above, if the angle of incidence is <0 ° and the rolling shape ratio is> 1.5, warping will occur as it is. Therefore, if the upper roll peripheral speed is smaller than the lower roll peripheral speed, Warpage can be prevented, bite incidence angle> 0 °, rolling shape ratio> 1.
In the case of No. 5, since downward warpage occurs as it is, it has been found that the downward warpage can be prevented by setting the upper roll peripheral speed> the lower roll peripheral speed.
【0017】一方、噛込入射角<0°で、圧延形状比
<1.5の場合では、上ロール周速<下ロール周速とす
れば下反りが防止でき、噛込入射角>0°、で圧延形
状比<1.5の場合では反り方向が逆転し、上ロール周
速>下ロール周速とすれば上反りが防止できることを見
出した。 On the other hand, when the bite incidence angle <0 °, the rolling shape ratio
In the case of <1.5, the upper roll peripheral speed <the lower roll peripheral speed
Can prevent roll-down, and can be rolled at a bite incidence angle> 0 °
When the shape ratio is <1.5, the warp direction is reversed and the upper roll
Speed> lower roll peripheral speed to prevent warpage.
Issued.
【0018】更に、図5の再圧延時の鋼板上下面温度差
と反りとの関係を示す図から噛込入射角=0、上ロール
と下ロール周速差=0の際に鋼材の上面と下面の温度差
(上面温度−下面温度)△T>0の場合には上反りとな
り、△T<0の場合には下反りとなることが判明した。Further, FIG. 5 shows the relationship between the temperature difference between the upper and lower surfaces of the steel sheet during re-rolling and the warpage. It has been found that when the temperature difference of the lower surface (upper surface temperature−lower surface temperature) △ T> 0, warpage occurs, and when △ T <0, downward warpage occurs.
【0019】このことから手段2のように、噛込入射
角<0°、圧延形状比>1.5の場合には二次圧延の途
中での冷却時における鋼材上面の平均温度>下面の平均
温度とすれば上反りが防止でき、噛込入射角>0°、
圧延形状比>1.5の場合には逆に上面の平均温度<下
面の平均温度とすれば上反りが防止できることを見出し
た。From this, as in the case of the means 2, when the bite incidence angle <0 ° and the rolling shape ratio> 1.5, the average temperature of the upper surface of the steel material during cooling during the secondary rolling> the average of the lower surface If the temperature is set, the warpage can be prevented, the bite incidence angle> 0 °,
Conversely, when the rolling shape ratio> 1.5, the average temperature of the upper surface < lower
It has been found that warpage can be prevented by setting the average temperature of the surface .
【0020】一方、噛込入射角<0°、圧延形状比<
1.5の場合では、上面の平均温度<下面の平均温度と
すれば下反りが防止でき、噛込入射角>0°、圧延形
状比<1.5の場合では反り方向が逆転し、上面の平均
温度>下面の平均温度とすれば下反りが防止できること
を見出した。 On the other hand, the bite incidence angle <0 ° and the rolling shape ratio <
In the case of 1.5, the average temperature of the upper surface <the average temperature of the lower surface and
By doing so, warpage can be prevented, biting incidence angle> 0 °, rolled type
When the shape ratio is less than 1.5, the warp direction is reversed,
It is possible to prevent downward warpage if the temperature> the average temperature of the lower surface
Was found.
【0021】尚、鋼材の上面の温度、下面の温度はサー
モトレーサーにて二次圧延時において圧延機に噛込まれ
る前の鋼材全体を測定して求めた平均値である。The temperatures of the upper surface and the lower surface of the steel material are average values obtained by measuring the entire steel material before being bitten by a rolling mill during secondary rolling by a thermotracer.
【0022】また、手段3の様に上ワークロール周速と
下ワークロール周速の制御、鋼材の上下面の温度制御を
同時に実施するとさらに良好な形状となることを種々の
検討により明らかとした。Various studies have revealed that a better shape can be obtained by simultaneously controlling the peripheral speeds of the upper work roll and the lower work roll and controlling the temperature of the upper and lower surfaces of the steel material as in the means 3. .
【0023】以上種々の条件にて検討したように二次圧
延時の圧延条件の最適制御、二次圧延前の上下面平均温
度差を適正に制御することによって、圧延中の反りを確
実に防止できるという優れた効果を得ることが可能とな
ることを知得した。As discussed above under various conditions, by optimally controlling the rolling conditions during the secondary rolling and properly controlling the average temperature difference between the upper and lower surfaces before the secondary rolling, the warpage during the rolling is reliably prevented. It has been found that it is possible to obtain an excellent effect of being able to do so.
【0024】即ち、鋼材のフロント部/テ−ル部の微小
な端部の形状及び図7に示すように鋼材の長さや搬送中
のバウンド等の操業変化によって噛込入射角が変化して
も、上下ロ−ルの周速、二次圧延時における圧延機噛込
み直前の鋼材の上下面温度を調整することで、二次圧延
中の鋼材の形状を平坦にする製造技術を確立した。ま
た、二次圧延前に強制冷却する鋼材の板厚が40mm以
下であると空冷による鋼材の抜熱が速くなり制御圧延時
の温度待ち時間が必然的に短くなることから、冷却水に
よる強制冷却と空冷に温度待ち時間に差が殆どない。こ
のことから対象鋼材の板厚は40mm以上とした。That is, even if the bite incidence angle changes due to the shape of the minute end of the front portion / tail portion of the steel material and the operation change such as the length of the steel material and the bounce during transportation as shown in FIG. By adjusting the peripheral speed of the upper and lower rolls and the upper and lower surface temperatures of the steel material immediately before the rolling mill is engaged in the secondary rolling, a manufacturing technique for flattening the shape of the steel material during the secondary rolling was established. Also, if the thickness of the steel material to be forcibly cooled before the secondary rolling is 40 mm or less, the heat removal of the steel material by air cooling becomes faster, and the temperature waiting time during the control rolling is inevitably shortened. And air cooling have little difference in temperature waiting time. For this reason, the thickness of the target steel material was set to 40 mm or more.
【0025】また、一次圧延温度はオーステナイトが再
結晶する温度域での圧延を実施することを前提としてい
るので850℃以上とした。また、二次圧延終了温度は
靱性を改善するためには未再結晶域での圧延が必須とな
るため720〜850℃の範囲とした。The primary rolling temperature is set to 850 ° C. or higher because it is assumed that rolling is performed in a temperature range in which austenite is recrystallized. In addition, the secondary rolling end temperature is in the range of 720 to 850 ° C. because rolling in an unrecrystallized region is essential to improve toughness.
【0026】[0026]
(実施例)本発明の実施例を従来例及び比較例と共に以
下に示す。供試鋼の成分は代表的な構造用鋼としての成
分を用い、本実施例に用いた鋼の化学成分を表1に示
す。(Examples) Examples of the present invention are shown below together with conventional examples and comparative examples. The components of the test steels are those used as typical structural steels. Table 1 shows the chemical components of the steels used in this example.
【0027】スラブの加熱温度、厚さ、一次圧延として
の粗圧延の圧延条件、移送厚(粗圧延後、所定の温度ま
で温度待ちをする板厚)での冷却−温度待ち条件、二次
圧延としての仕上圧延の圧延条件等の製造条件とその製
造結果を表2−1及び表2−2に示す。また、仕上圧延
条件を表3−1及び表3−2、表3−3に示す。Heating temperature and thickness of slab, rolling conditions for rough rolling as primary rolling, cooling at transfer thickness (plate thickness waiting for temperature to predetermined temperature after rough rolling), temperature waiting condition for secondary rolling, secondary rolling Table 2-1 and Table 2-2 show production conditions such as rolling conditions for finish rolling as described above and the production results. Table 3-1 and Table 3-2 and Table 3-3 show the finish rolling conditions.
【0028】この表2−1、2−2及び表3−1、3−
2、3−3に示す様に、本発明例の鋼番1、13、2
1、は手段1(請求項1−仕上圧延機の上下ワークロー
ルの周速度調整)に対応する例で、鋼番4、22〜24
は手段2(請求項2−鋼材の表裏面温度差調整)に対応
する例で、鋼番5、7、9、11、15、17、19、
は手段3(請求項3−仕上圧延機の上下ワークロールの
周速度調整と鋼材の表裏面温度差調整の併用)に対応す
る例であり、このいずれの例も移送厚での温度待ち時間
が大幅に短縮され、仕上げ圧延中に反り発生がなく反り
修正が不必要で、かつ靱性も良好となった。Tables 2-1 and 2-2 and Tables 3-1 and 3-
As shown in 2, 3-3, steel numbers 1, 13, 2
Reference numeral 1 denotes an example corresponding to the means 1 (Claim 1-Adjustment of peripheral speed of upper and lower work rolls of a finishing mill).
Is an example corresponding to the means 2 (Claim 2-Adjustment of temperature difference between front and back of steel material), and steel numbers 5, 7, 9, 11, 15, 17, 19,
Is an example corresponding to the means 3 (Claim 3-Combination of the peripheral speed adjustment of the upper and lower work rolls of the finishing mill and the temperature difference adjustment of the front and back surfaces of the steel material). It was greatly shortened, no warpage occurred during finish rolling, no warpage correction was required, and good toughness was obtained.
【0029】これに対して従来例である鋼番2、6、
8、10、12、16及び20は粗圧延後仕上圧延に入
るまでの間で空冷を行ったものであり、該鋼番8、1
2、16は仕上圧延中に鋼材の反りが大きくなって途中
で圧延を中止した。また、鋼番2、6、10、20、は
途中で圧延を中止するまではならなかったものの移送厚
での温度待ち時間が長くなり、しかも、鋼材の生産性、
靱性とも大幅に劣化した。また、比較例である鋼番3、
18は粗圧延後、冷却水で強制冷却を行ったものの仕上
圧延中の圧延条件が適正でなかった。即ち、噛込入射角
が負で、圧延形状比が1.5以下であったにもかかわら
ず仕上圧延機の上ロールの周度を下ロールより高速にし
た為、鋼番3は圧延途中で鋼材に反りが発生し圧延中止
となった。また、鋼番18は1パス目〜3パス目の後に
反り修正が各々必要となった。On the other hand, steel Nos. 2, 6,
Nos. 8, 10, 12, 16 and 20 were air-cooled before rough rolling and finishing rolling.
In Nos. 2 and 16, the warpage of the steel material increased during the finish rolling, and the rolling was stopped halfway. In addition, although steel numbers 2, 6, 10, and 20 did not have to stop rolling halfway, the temperature waiting time at the transfer thickness became longer, and furthermore, the productivity of steel materials,
Both toughness deteriorated significantly. In addition, steel number 3, which is a comparative example,
Sample No. 18 was subjected to forced cooling with cooling water after rough rolling, but the rolling conditions during finish rolling were not appropriate. That is, although the bite incidence angle was negative and the rolling shape ratio was 1.5 or less, the circumference of the upper roll of the finishing mill was set to be higher than that of the lower roll. Rolling was stopped due to warpage of the steel material. Steel No. 18 required warpage correction after the first to third passes.
【0030】さらに、鋼番14は噛込入射角が正で、形
状比が1.5以下であったにもかかわらず仕上圧延機の
上ワークロールを下ワークロールより高速にしていた
為、反りが発生圧延し、圧延中止までに至らなかったが
仕上圧延の2パス目と4パス目の後で圧延作業を中断し
て反り修正を実施した。Further, Steel No. 14 had a positive bite incidence angle and the upper work roll of the finishing mill was higher in speed than the lower work roll even though the shape ratio was 1.5 or less. The rolling operation was interrupted after the second and fourth passes of finish rolling, and the warpage was corrected.
【0031】[0031]
【表1】 [Table 1]
【0032】[0032]
【表2−1】 [Table 2-1]
【0033】[0033]
【表2−2】 [Table 2-2]
【0034】[0034]
【表3−1】 [Table 3-1]
【0035】[0035]
【表3−2】 [Table 3-2]
【0036】[0036]
【表3−3】 [Table 3-3]
【0037】[0037]
【発明の効果】以上説明したごとく、本発明によると、
反りのない形状の良好な、しかも、優れた靱性を有する
鋼板を無駄な温度待ちをすることなく生産性良く、且
つ、圧延作業性良く製造することが可能となり、当該分
野における効果は極めて大きい。As described above, according to the present invention,
A steel sheet having a good shape without warpage and having excellent toughness can be manufactured with high productivity and good rolling workability without waiting for useless temperatures, and the effect in this field is extremely large.
【図1】圧延中の鋼板の温度推移を示す図である。FIG. 1 is a diagram showing a temperature transition of a steel sheet during rolling.
【図2】製造工程の差による熱履歴の差を示す図であ
る。FIG. 2 is a diagram showing a difference in heat history due to a difference in a manufacturing process.
【図3】途中冷却による靱性改善効果を示す図である。FIG. 3 is a view showing a toughness improving effect by cooling in the middle.
【図4】再圧延時の圧延条件と反りとの関係を示す図で
ある。FIG. 4 is a diagram showing the relationship between rolling conditions and warpage during re-rolling.
【図5】再圧延時の鋼板上下温度差と反りとの関係を示
す図である。FIG. 5 is a diagram showing a relationship between a difference in vertical temperature of a steel sheet and warpage during re-rolling.
【図6】噛込入射角を示す模式図である。FIG. 6 is a schematic diagram showing a bite incident angle.
【図7】スラブの長が変化すると噛込入射角が変化する
ことを示す模式図である。FIG. 7 is a schematic diagram showing that the bite incidence angle changes as the length of the slab changes.
1 鋼材 2 上ワ−クロ−ル 3 下ワ−クロ−ル 1 Steel 2 Upper work 3 Lower work
───────────────────────────────────────────────────── フロントページの続き (58)調査した分野(Int.Cl.7,DB名) C21D 8/00 - 8/10 B21B 3/00 B21B 37/00 - 37/76 ──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. 7 , DB name) C21D 8/00-8/10 B21B 3/00 B21B 37/00-37/76
Claims (3)
0mm以上の鋼材を強制冷却し、その後、二次圧延を行
って720〜850℃で該圧延を終了することにより靱
性の優れた鋼板を製造する方法において、前記二次圧延
を行う際、該圧延の各パス毎の鋼材の噛込入射角と圧延
形状比を予測し、その予測した噛込入射角と圧延形状比
から下記〜のいずれに該当するかを判定し、この判
定した〜の上ワークロールと下ワークロールの周速
の関係となるように、前記二次圧延を行う二次圧延機の
各パス毎の上ワークロールと下ワークロールの周速を調
整することを特徴とする靱性の優れた鋼板の製造方法 噛込入射角<0°、圧延形状比>1.5の場合 上ロール周速<下ロール周速 噛込入射角>0°、圧延形状比>1.5の場合上ロール周速>下ロール周速 噛込入射角<0°、圧延形状比<1.5の場合上ロール周速<下ロール周速 噛込入射角>0°、圧延形状比<1.5の場合上ロール周速>下ロール周速 但し、圧延形状比=(接触投影孤長/平均板厚)1. Thickness 4 after primary rolling at 850 ° C. or higher
In a method for producing a steel sheet having excellent toughness by forcibly cooling a steel material of 0 mm or more and then performing secondary rolling and terminating the rolling at 720 to 850 ° C., when the secondary rolling is performed, Predict the bite incidence angle and rolling shape ratio of the steel material for each pass of, and determine which of the following from the predicted bite incidence angle and the rolled shape ratio, and determine the upper workpiece The toughness characterized by adjusting the peripheral speed of the upper work roll and the lower work roll for each pass of the secondary rolling mill that performs the secondary rolling so that the relationship between the peripheral speed of the roll and the lower work roll is obtained. excellent production method bite angle of incidence of the steel plate <0 °, rolling shape ratio> if the roll peripheral speed of 1.5 <lower roll peripheral speed bite incident angle> 0 °, the case of the rolling shape ratio> 1.5 roll peripheral speed> lower roll peripheral speed bite angle of incidence <0 °, the field of the rolling shape ratio <1.5 Upper roll peripheral speed <lower roll peripheral speed bite incident angle> 0 °, rolling shape ratio <case on a roll peripheral speed of 1.5> lower roll peripheral speed, however, rolling shape ratio = (contact projection arc length / average thickness )
0mm以上の鋼材を強制冷却し、その後、二次圧延を行
って720〜850℃で該圧延を終了することにより靱
性の優れた鋼板を製造する方法において、前記二次圧延
を行う際、該圧延の各パス毎の鋼材の噛込入射角と圧延
形状比を予測し、その予測した噛込入射角と圧延形状比
から下記〜のいずれに該当するかを判定し、この判
定した〜の鋼材の上面と下面の平均温度との関係と
なるように、前記鋼材の上、下面の強制冷却量を調整す
ることを特徴とする靱性の優れた鋼板の製造方法 噛込入射角<0°、圧延形状比>1.5の場合 上面の平均温度>下面の平均温度 噛込入射角>0°、圧延形状比>1.5の場合 上面の平均温度<下面の平均温度 噛込入射角<0°、圧延形状比<1.5の場合 上面の平均温度<下面の平均温度 噛込入射角>0°、圧延形状比<1.5の場合 上面の平均温度>下面の平均温度 但し、圧延形状比=(接触投影孤長/平均板厚)2. A sheet thickness of 4 after primary rolling at 850 ° C. or higher.
In a method for producing a steel sheet having excellent toughness by forcibly cooling a steel material of 0 mm or more and then performing secondary rolling and terminating the rolling at 720 to 850 ° C., when the secondary rolling is performed, Predict the bite incidence angle and rolling shape ratio of the steel material for each pass, and determine which of the following from the predicted bite incidence angle and the rolling shape ratio to apply, the steel material of the determined ~ A method for producing a steel sheet having excellent toughness, characterized in that the forced cooling amount of the upper and lower surfaces of the steel material is adjusted so as to have a relationship between the average temperature of the upper surface and the lower surface. In the case of ratio> 1.5, the average temperature of the upper surface> the average temperature of the lower surface When the angle of incidence> 0 ° and the rolling shape ratio> 1.5, the average temperature of the upper surface <the average temperature of the lower surface The angle of incidence <0 ° Rolling shape ratio <1.5 Average temperature on the upper surface <Average temperature on the lower surface Biting incident angle> 0 °, Rolling shape ratio <1.5 Average temperature of upper surface> Average temperature of lower surface However, rolling shape ratio = (contact projection arc length / average plate thickness)
0mm以上の鋼材を強制冷却し、その後、二次圧延を行
って720〜850℃で該圧延を終了することにより靱
性の優れた鋼板を製造する方法において、前記二次圧延
を行う際、該圧延の各パス毎の鋼材の噛込入射角と圧延
形状比を予測し、その予測した噛込入射角と圧延形状比
から下記〜のいずれに該当するかを判定し、この判
定した〜の鋼材の上面と下面の平均温度、上ワーク
ロールと下ワークロールの周速の関係となるように、前
記鋼材の上、下面の強制冷却量及び鋼材噛み込み前の前
記二次圧延機のの各パス毎の上ワークロールと下ワーク
ロールの周速を各々調整することを特徴とする靱性の優
れた鋼板の製造方法 噛込入射角<0°、圧延形状比>1.5の場合 上面の平均温度>下面の平均温度で、且つ、上ロール周
速<下ロール周速 噛込入射角>0°、圧延形状比>1.5の場合 上面の平均温度<下面の平均温度で、且つ、上ロール周
速>下ロール周速 噛込入射角<0°、圧延形状比<1.5の場合 上面の平均温度<下面の平均温度で、且つ、上ロール周
速<下ロール周速 噛込入射角>0°、圧延形状比<1.5の場合 上面の平均温度>下面の平均温度で、且つ、上ロール周
速>下ロール周速 但し、圧延形状比=(接触投影孤長/平均板厚)3. A sheet thickness of 4 after primary rolling at 850 ° C. or higher.
In a method for producing a steel sheet having excellent toughness by forcibly cooling a steel material of 0 mm or more and then performing secondary rolling and terminating the rolling at 720 to 850 ° C., when the secondary rolling is performed, Predict the bite incidence angle and rolling shape ratio of the steel material for each pass, and determine which of the following from the predicted bite incidence angle and the rolling shape ratio to apply, the steel material of the determined ~ The average temperature of the upper surface and the lower surface, the forced cooling amount of the upper and lower surfaces of the steel material, and each pass of the secondary rolling mill before biting the steel material so that the peripheral speed of the upper work roll and the lower work roll is related. A method of manufacturing a steel sheet having excellent toughness, characterized in that the peripheral speeds of the upper work roll and the lower work roll are adjusted respectively. In the case where the bite incidence angle <0 ° and the rolling shape ratio> 1.5, the average temperature of the upper surface> The average temperature of the lower surface and the upper roll peripheral speed <the lower roll peripheral Speed When the bite incidence angle> 0 ° and the rolling shape ratio> 1.5: Upper surface average temperature <Lower surface average temperature, and upper roll peripheral speed> lower roll peripheral speed Bite incidence angle <0 °, rolled shape When the ratio is less than 1.5, the average temperature of the upper surface is smaller than the average temperature of the lower surface, and the upper roll has a circumference.
Speed <lower roll peripheral speed bite incidence angle> 0 °, rolling shape ratio <1.5 Average temperature of upper surface> average temperature of lower surface and upper roll circumference
Speed> lower roll peripheral speed where rolling shape ratio = (contact projection arc length / average plate thickness)
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JP34613095A JP3291188B2 (en) | 1995-12-12 | 1995-12-12 | Manufacturing method of steel sheet with excellent toughness |
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JP34613095A JP3291188B2 (en) | 1995-12-12 | 1995-12-12 | Manufacturing method of steel sheet with excellent toughness |
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JPH09165619A JPH09165619A (en) | 1997-06-24 |
JP3291188B2 true JP3291188B2 (en) | 2002-06-10 |
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