JPH07166292A - Hot rolled high strength steel plate excellent in drawability and production thereof - Google Patents
Hot rolled high strength steel plate excellent in drawability and production thereofInfo
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- JPH07166292A JPH07166292A JP4282294A JP4282294A JPH07166292A JP H07166292 A JPH07166292 A JP H07166292A JP 4282294 A JP4282294 A JP 4282294A JP 4282294 A JP4282294 A JP 4282294A JP H07166292 A JPH07166292 A JP H07166292A
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- rolling
- steel sheet
- hot
- rolled
- steel plate
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- Heat Treatment Of Sheet Steel (AREA)
- Heat Treatment Of Steel (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、絞り性に優れ、強度が
高い熱延鋼板およびその製造方法に関するもので、自動
車用あるいは産業機械用材料として加工性とともに強度
を有する冷延鋼板に替わる安価な熱延鋼板を提供するも
のである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot-rolled steel sheet having excellent drawability and high strength, and a method for producing the same, which is an inexpensive alternative to cold-rolled steel sheet having workability and strength as a material for automobiles or industrial machines. A hot rolled steel sheet is provided.
【０００２】[0002]
【従来の技術】従来、絞り用鋼板としては冷延鋼板が用
いられてきたが、板厚の厚い材料が必要な場合や、コス
ト低減・生産性向上を狙う場合には、熱延鋼板の使用が
検討されてきた。一般的に熱延鋼板は冷延鋼板と比べる
と深絞り性に劣っておりこれを補うために延性（伸び）
の向上が図られている。たとえば、特開平２−１４５７
４８号公報では、低炭素鋼板をフェライト再結晶温度域
での圧延を５０％以上含む熱間圧延を行うことで、強度
３５kgf/mm2 以上で４０％以上の高延性鋼板が得られる
ことを示している。しかし、この方法では製造された熱
延鋼板の絞り性が不十分で、また鋼板表面状態も冷延鋼
板と異なるため冷延鋼板の代替として使用するには範囲
が限られていた。2. Description of the Related Art Conventionally, cold-rolled steel sheets have been used as drawing steel sheets. However, use of hot-rolled steel sheets when a thick material is required or cost reduction and productivity improvement are aimed at. Has been considered. Generally, hot-rolled steel sheet is inferior in deep drawability to cold-rolled steel sheet, and to compensate for this, ductility (elongation)
Is being improved. For example, Japanese Patent Laid-Open No. 2-1457
In Japanese Patent Publication No. 48, it is shown that high-ductile steel sheet having a strength of 35 kgf / mm 2 or more and a ductility of 40% or more can be obtained by hot rolling a low carbon steel sheet in a ferrite recrystallization temperature range of 50% or more. ing. However, in this method, the drawability of the hot-rolled steel sheet produced is insufficient and the surface state of the steel sheet is different from that of the cold-rolled steel sheet, so that the range of use as a substitute for the cold-rolled steel sheet is limited.
【０００３】[0003]
【発明が解決しようとする課題】本発明は、上記の問題
を解決するため、鋼板強度の上昇とともに深絞り性に
優れた熱延鋼板、さらに冷延鋼板に匹敵する表面性状
を有する熱延鋼板、およびその製造方法を提供するもの
である。SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a hot-rolled steel sheet excellent in deep drawability with an increase in steel sheet strength, and a hot-rolled steel sheet having a surface texture comparable to that of a cold-rolled steel sheet. And a manufacturing method thereof.
【０００４】[0004]
【課題を解決するための手段】本発明の構成は、重量％
で０．００３≦Ｃ≦０．０４％、Ｓｉ≦０．０３％、
１．５≦Ｍｎ≦３．０％、Ｐ≦０．１％、Ｓ≦０．０１
％、Ｎ≦０．００５％、０．０３≦Ｔｉ≦０．２％、か
つ４８（Ｃ／１２＋Ｎ／１４）≦Ｔｉを満足し、その他
不可避的元素を含む鋼片を９５０〜１１００℃で加熱し
た後、９００〜９５０℃で粗圧延を終了した後、６００
〜８００℃の間を各パス１５〜３０％で摩擦係数μ≦
０．１５となるように潤滑を施しながら圧延を行った
後、自己焼鈍または加熱処理によって６５０〜７５０℃
とした後に巻き取り、酸洗した後にスキンパスによって
１〜３％で圧下して巻き取ることによって表面粗度Ｒａ
≦２μｍで、組織はフェライト単相で結晶粒径≦２０μ
ｍである熱延高強度鋼板を得ることができる。また、粗
圧延と仕上圧延の間で９００℃以上で５分以上の温度保
持を行うことにより延性の向上も実現できる。The structure of the present invention has a weight percentage.
0.003 ≦ C ≦ 0.04%, Si ≦ 0.03%,
1.5 ≦ Mn ≦ 3.0%, P ≦ 0.1%, S ≦ 0.01
%, N ≦ 0.005%, 0.03 ≦ Ti ≦ 0.2%, and 48 (C / 12 + N / 14) ≦ Ti, and a steel slab containing other inevitable elements is heated at 950 to 1100 ° C. After finishing the rough rolling at 900 to 950 ° C., 600
Coefficient of friction μ ≤ 15% to 30% for each pass between ~ 800 ° C
After rolling while giving lubrication to 0.15, it is 650 to 750 ° C. by self-annealing or heat treatment.
The surface roughness Ra is
≦ 2μm, structure is ferrite single phase, grain size ≦ 20μ
It is possible to obtain a hot-rolled high-strength steel sheet having m. Further, by maintaining the temperature at 900 ° C. or higher for 5 minutes or more between the rough rolling and the finish rolling, the ductility can be improved.
【０００５】[0005]
【作用】鋼板の用途は、成形される部品によって使い分
けられる。一般的には、成形加工の程度が大きい場合に
は、加工性、すなわち伸びや絞り性が必要になるが、そ
の替わりに強度は低下してくる。また、高い強度を有す
る場合には、加工性が低下する。従来の加工用熱延鋼板
の製造では、鉄の純度を高めることで加工性を向上させ
る方法が多く、これをγ域やα域で圧延することで極軟
熱延鋼板が得られてきた。しかし、鉄本来の特性はある
程度の耐強度が必要である。したがって、強度が上昇し
てかつ、加工性を保った熱延鋼板ができればその用途が
拡大されてくる。[Function] The usage of the steel sheet depends on the parts to be formed. Generally, when the degree of molding is large, workability, that is, elongation and drawability is required, but the strength is lowered instead. Further, when it has high strength, the workability is lowered. In the conventional manufacturing of hot-rolled steel sheets for working, there are many methods for improving workability by increasing the purity of iron, and extremely soft hot-rolled steel sheets have been obtained by rolling this in the γ region or α region. However, the inherent properties of iron require some strength resistance. Therefore, if a hot-rolled steel sheet having increased strength and maintaining workability can be produced, its application will be expanded.
【０００６】本発明者らは、これを目的として検討を重
ねた。その狙いは、強度アップ（ＴＳ≧３５kgf/m
m2 ）、絞り性の向上（ｒ平均値≧１．２）、表面
性状の向上（Ｒａ≦２μｍ）である。まず、熱延鋼板で
は特性値が低い、の絞り性の向上については、α域で
の潤滑圧延で向上させることを検討した。従来、極低炭
素鋼においてこの方法で高ｒ平均値が得られている。こ
れは、極表層に絞り性を劣化させる｛１１０｝面が生成
するが、潤滑圧延によってこの層は消滅し中心部と同じ
｛１１１｝面が生成して、絞り性を向上させるためであ
る。しかし、高強度側では加工性が劣化するため十分な
検討がなされていない。そこで、この方法をベースとし
て検討を行った。また延性については粗圧延と仕上圧延
の間で適当な温度範囲で保持することにより向上するこ
とが判明した。The present inventors have conducted extensive studies for this purpose. The aim is to increase the strength (TS ≧ 35kgf / m
m 2 ), improvement of drawability (r average value ≧ 1.2), and improvement of surface texture (Ra ≦ 2 μm). First, with regard to the improvement of the drawability of the hot rolled steel sheet, which has a low characteristic value, it was examined to improve it by lubrication rolling in the α region. Conventionally, high r average values have been obtained by this method in ultra low carbon steel. This is because the {110} plane that deteriorates the drawability is generated in the extreme surface layer, but this layer disappears due to the lubrication rolling and the {111} plane that is the same as the central portion is generated to improve the drawability. However, since the workability is deteriorated on the high strength side, sufficient consideration has not been made. Therefore, we conducted a study based on this method. It was also found that the ductility is improved by maintaining the temperature within an appropriate temperature range between rough rolling and finish rolling.
【０００７】つぎに、の強度の上昇は、固溶Ｃをなく
すためにＴｉを添加してできる析出物による強化と、固
溶強化を検討した。この結果、ＰおよびＭｎで強化した
場合は、α域潤滑圧延によって得られる絞り性を損なわ
ずに強度上昇が可能であることが判明した。この場合の
組織は、フェライト単相かつ２０μｍ以下の細粒であ
り、加工性に適した鋼板となった。粒径については、図
４に示すように２０μｍを超えた場合は、部品に成形後
に肌荒れが発生し、商品価値が低下する。このため、鋼
板の結晶粒径は２０μｍ以下に抑える必要がある。Next, regarding the increase in the strength of (5), strengthening by a precipitate formed by adding Ti to eliminate solid solution C and solid solution strengthening were investigated. As a result, it was found that when strengthened with P and Mn, the strength can be increased without impairing the drawability obtained by the α region lubrication rolling. The structure in this case was a ferrite single phase and fine grains of 20 μm or less, and the steel plate was suitable for workability. Regarding the particle size, as shown in FIG. 4, when the particle size exceeds 20 μm, the surface of the part is roughened after molding, and the commercial value is reduced. Therefore, it is necessary to suppress the crystal grain size of the steel sheet to 20 μm or less.
【０００８】また、の表面性状は酸洗直後にスキンパ
スをかけることで、冷延鋼板並の２μｍ以下の粗度が得
られ、外観上も変わらない表面性状が得られることが判
明した。通常、酸洗した後のコイルをスキンパスして
も、このような表面性状は得られず、酸洗ラインの中で
スキンパスをかけることが重要である。この理由は明ら
かではないが、鋼板が酸洗されて新生面が表面に出て、
ただちに圧下するため表面酸化や汚れがない状態で圧下
することが影響していると考えられる。Further, it was found that by applying a skin pass immediately after pickling, a surface texture of 2 μm or less comparable to that of a cold-rolled steel sheet can be obtained and a surface texture that does not change in appearance can be obtained. Usually, even if the coil after pickling is skin-passed, such a surface property is not obtained, and it is important to apply a skin-pass in the pickling line. The reason for this is not clear, but the steel sheet is pickled and the new surface appears on the surface,
Since the pressure is immediately reduced, it is considered that the reduction is affected without surface oxidation or contamination.
【０００９】このような作用をもとにして決定された、
発明範囲の限定条件を以下に詳細に説明する。Ｃは、絞
り性向上のためには極力低下させたい元素であるが、強
度確保のためには必要な元素である。強度への寄与は、
Ｔｉとの間で形成される析出物による。下限を０．００
３％にしたのは、これより低いとＭｎ，Ｐの添加による
固溶強化によっても３５kgf/mm2 以上の強度が確保でき
なくなるためである。また、上限を０．０４％にしたの
は、これ以上では、固溶Ｃをなくすために添加するＴｉ
量が増加してコスト高となること、またＴｉＣの粗大化
のため、析出物強化代が停滞してしまうためである。Based on such an action,
The conditions for limiting the scope of the invention will be described in detail below. C is an element that is desired to be reduced as much as possible in order to improve drawability, but is an element necessary for ensuring strength. The contribution to strength is
Due to the precipitate formed with Ti. Lower limit 0.00
The reason why the content is 3% is that if it is lower than this, strength of 35 kgf / mm 2 or more cannot be secured even by solid solution strengthening by addition of Mn and P. Further, the upper limit is set to 0.04% because the Ti added to eliminate the solid solution C is more than this.
This is because the amount increases and the cost increases, and the coarsening of TiC causes the precipitation strengthening margin to stagnate.
【００１０】Ｎは、絞り性向上のために極力低下させた
い元素であり、上限を０．００５％とした。Ｔｉ量は、
固溶Ｃ，Ｎを消滅させるためにはＣ，Ｎ量によりほぼ決
まり、４８（Ｃ／１２＋Ｎ／１４）≦Ｔｉを満たせば良
い。その下限値０．０３％は、析出強化分として最低限
必要量であり、また上限値０．２％以上は、コスト高か
つこれ以上の強度への効き代は期待できない。Ｓｉは強
化元素として使えるが、他方、ＳｉスケールやＭｎ−Ｓ
ｉ系介在物起因となり有害である。本発明では延性への
影響がなく有害介在物を生成しない条件としてＳｉ≦
０．０３％とした。N is an element to be reduced as much as possible in order to improve drawability, and the upper limit is set to 0.005%. The amount of Ti is
In order to eliminate the solid solution C and N, it is almost determined by the amounts of C and N, and it is sufficient to satisfy 48 (C / 12 + N / 14) ≦ Ti. The lower limit value of 0.03% is the minimum necessary amount for precipitation strengthening, and the upper limit value of 0.2% or more cannot be expected to be costly and to have a further effect on strength. Si can be used as a strengthening element, but on the other hand, Si scale and Mn-S
It is harmful due to i-type inclusions. In the present invention, as a condition that does not affect the ductility and does not generate harmful inclusions, Si ≦
It was set to 0.03%.
【００１１】Ｓも有害介在物を形成し易い元素であり、
延性への悪影響を防ぐために、Ｓ≦０．０１％に規制し
た。Ｍｎは本発明では、図１，２に示すように、絞り性
を損なわずに強度アップが可能な有効な強化元素であり
積極的に活用する。３５kgf/mm2 以上を得るためには、
Ｐや析出物の併用でも１．５％以上は必要である。しか
し、３．０％以上では、図２で明らかなように伸びの低
下が著しくまたコスト高になる。Ｐも絞り性を損なわず
に強度上昇が可能である。しかし、多量の添加は、靭性
劣化、溶接性への悪影響があるため、この影響を避ける
ために上限を０．１％に規制した。S is also an element that easily forms harmful inclusions,
In order to prevent adverse effects on ductility, S ≦ 0.01% is regulated. In the present invention, as shown in FIGS. 1 and 2, Mn is an effective strengthening element capable of increasing strength without impairing drawability, and is actively utilized. To get over 35 kgf / mm 2 ,
Even if P and precipitates are used together, 1.5% or more is necessary. However, if it is 3.0% or more, the elongation is remarkably lowered and the cost becomes high, as is apparent from FIG. P can also increase the strength without impairing the drawability. However, addition of a large amount adversely affects toughness and weldability, so the upper limit was set to 0.1% in order to avoid this effect.
【００１２】熱間圧延に際しては、再加熱スラブを用い
るか、直送圧延材を用いるかは重要でない。また、連続
鋳造する際に薄手ＣＣを使用しても良い。Ｃ，Ｎを析出
物として固着するために９５０〜１１００℃で加熱する
ことが有効である。析出させるための時間として１５分
以上は必要である。また、加熱後の粗圧延では、γ低温
域で圧延しておくことが必要で、これは、γの結晶粒を
細粒とし変態後のα域も細粒化するためα域圧延後に再
結晶する絞り性に有効な結晶方位｛１１１｝面を多く出
させるのに効果がある。したがってＡｒ3 直上の９００
〜９５０℃で粗圧延を終了させる。At the time of hot rolling, it is not important to use a reheat slab or a straight rolled material. Moreover, you may use thin CC at the time of continuous casting. It is effective to heat at 950 to 1100 ° C. in order to fix C and N as precipitates. The time required for precipitation is 15 minutes or more. Further, in the rough rolling after heating, it is necessary to perform rolling in the γ low temperature region. This is because recrystallization after α region rolling is performed because the γ crystal grains are made fine and the α region after transformation is also made fine. It is effective in producing a large number of crystal orientation {111} planes that are effective for the drawability. Therefore 900 directly above Ar 3
The rough rolling is completed at ~ 950 ° C.
【００１３】その後仕上圧延を行うわけであるが、粗圧
延終了後すぐに仕上圧延を行っても良いが、粗圧延後９
００℃以上で５分以上保持することにより、延性の向上
も実現される。この温度保持はいわゆるコイルボックス
を用いることにより容易に達成される。仕上圧延はα域
で開始する必要があるが、このためには、生産効率を考
慮して、粗−仕上間で鋼板を冷却しても良い。仕上開始
をα域で行うのは、通常のタンデムの連続熱間圧延の
途中でγからαに変態すると、変形抵抗が大幅に変わる
ために圧延操業が不安定になり、トラブルの原因になり
易いためこれを防止することと、最初からα域圧延で
開始することで、α域の蓄積歪を増やして、フェライト
の再結晶を起こし易くするためである。また余り低すぎ
るとロール負荷が大きくなりすぎるため規制が必要とな
る。このために仕上圧延温度は、６００〜８００℃で行
う。After that, finish rolling is performed, but finish rolling may be performed immediately after the completion of rough rolling.
By maintaining the temperature at 00 ° C. or higher for 5 minutes or longer, improvement in ductility is also realized. This temperature maintenance is easily achieved by using a so-called coil box. The finish rolling needs to be started in the α region, but for this purpose, the steel plate may be cooled between the rough and finish in consideration of production efficiency. Finishing is done in the α region because if the transformation from γ to α occurs during normal tandem continuous hot rolling, the deformation resistance changes drastically and the rolling operation becomes unstable, which easily causes troubles. Therefore, by preventing this and starting the α region rolling from the beginning, the accumulated strain in the α region is increased to facilitate recrystallization of ferrite. On the other hand, if it is too low, the roll load will be too large, and regulation will be necessary. Therefore, the finish rolling temperature is 600 to 800 ° C.
【００１４】絞り性の向上のために、仕上圧延はロール
に油濃度の高い溶液を吹き付けたり、ロール表面への塗
油等の方法によって潤滑圧延を行う必要がある。この時
の摩擦係数がμ≦０．１５であれば、潤滑効果は十分で
表層の剪断層を除くことができる。しかし、摩擦係数が
低い場合は、噛み込みスリップ等のトラブルが生じるの
と、低摩擦係数での圧延を保つために、各圧延機での圧
下率は１５〜３０％で行う必要がある。In order to improve the drawability, the finish rolling needs to be performed by lubrication rolling by spraying a solution having a high oil concentration on the roll or applying oil to the roll surface. If the friction coefficient at this time is μ ≦ 0.15, the lubricating effect is sufficient and the shear layer in the surface layer can be removed. However, when the coefficient of friction is low, troubles such as biting slip occur, and in order to keep rolling at a low coefficient of friction, it is necessary to carry out a rolling reduction of 15 to 30% in each rolling mill.
【００１５】α域圧延後の鋼板の組織は加工組織になっ
ている。このために、加工αを再結晶させる必要があ
る。したがって巻き取った状態で６５０〜８００℃の再
結晶温度以上にしてやれば良い。これは、仕上−巻き取
り間の加熱や、近接コイラーを利用した自己焼鈍法や、
コイルボックスによる再加熱を行う方法がある。The structure of the steel sheet after the α region rolling is a work structure. For this reason, it is necessary to recrystallize the processed α. Therefore, the recrystallization temperature of 650 to 800 ° C. or higher in the wound state is sufficient. This is heating between finishing-winding, self-annealing method using a proximity coiler,
There is a method of reheating with a coil box.
【００１６】つぎに、熱延で生成したスケールを酸洗ラ
インで剥離した後、そのままスキンパス圧下を行い巻き
取る。この工程は、冷延鋼板に匹敵する表面状態にする
ために重要である。この時の圧下率は、１％以上でロー
ル表面が転写され、図３で示すように冷延鋼板に匹敵す
る表面粗度状態が得られる。しかし、３％超では、伸び
の劣化が顕著になるため１〜３％の範囲内に規制した。
以上の製造により、表面粗度Ｒａ≦２μｍで、組織はフ
ェライト単相で結晶粒径≦２０μｍである３５kgf/mm2
以上の熱延高強度鋼板を得ることができる。Next, the scale produced by hot rolling is peeled off on the pickling line, and then directly subjected to skin pass pressure reduction and wound up. This step is important for achieving a surface condition comparable to that of cold rolled steel sheet. At this time, when the rolling reduction is 1% or more, the roll surface is transferred, and a surface roughness state comparable to that of the cold rolled steel sheet is obtained as shown in FIG. However, if it exceeds 3%, the deterioration of elongation becomes remarkable, so the content is regulated within the range of 1 to 3%.
By the above production, the surface roughness Ra is ≦ 2 μm, the structure is ferrite single phase, and the crystal grain size is ≦ 20 μm. 35 kgf / mm 2
The above hot rolled high strength steel sheet can be obtained.
【００１７】[0017]
【実施例】成分の影響を知るために、表１に示す成分の
鋼材を用いて、表２に示す条件で圧延を行った。潤滑圧
延油として、キュードル５１４９を用い、水と混合して
圧延ロール表面に噴射した。圧延終了後巻き取り処理を
行って、その後酸洗−スキンパスを行った後、サンプル
を採取し、材質調査を行った。調査は、表面粗度、引張
試験（ＪＩＳ５号）、結晶粒径測定を行った。その結果
を、表２に示す。[Examples] In order to know the influence of the components, steel materials having the components shown in Table 1 were used and rolled under the conditions shown in Table 2. Cudle 5149 was used as the lubricating rolling oil, mixed with water and sprayed onto the surface of the rolling roll. After the completion of rolling, a winding process was performed, and after that, pickling and skin pass were performed, and then a sample was collected and a material examination was performed. In the investigation, surface roughness, tensile test (JIS No. 5), and crystal grain size were measured. The results are shown in Table 2.
【００１８】[0018]
【表１】 [Table 1]
【００１９】[0019]
【表２】 [Table 2]
【００２０】[0020]
【表３】 [Table 3]
【００２１】[0021]
【表４】 [Table 4]
【００２２】[0022]
【表５】 [Table 5]
【００２３】サンプルNo．１，２，３，４，５はとも
に、熱延以降の条件は、本発明範囲に入っている。しか
し、Ｍｎ量が少ないＤ材を用いたNo．４のサンプルは強
度が低く、３５kgf/mm2 に届かなかった。また結晶粒径
も大きく２０μｍを超えた。Sample No. For 1, 2, 3, 4, and 5, the conditions after hot rolling are within the scope of the present invention. However, in the case of using No. D material with a small amount of Mn, Sample No. 4 had low strength and did not reach 35 kgf / mm 2 . Also, the crystal grain size was large and exceeded 20 μm.
【００２４】表３は、本発明の成分範囲である鋼種Ａ，
Ｃを用いて熱延条件を調べた結果である。サンプルNo．
１，２は、粗圧延温度が外れたため、仕上前の細粒フェ
ライトが得られず、製品板の結晶粒径が大きくなり、ま
たｒ平均値が低下した。No．３は、仕上開始温度が高す
ぎたため、フェライトに付加された歪量が少なく、再結
晶が起こりにくかったため、粗大な回復粒となり、強
度、伸び、ｒ平均値とも悪かった。Table 3 shows the steel grade A, which is the composition range of the present invention,
It is the result of having investigated the hot rolling conditions using C. Sample No.
In Nos. 1 and 2, since the rough rolling temperature was out of the range, fine-grained ferrite before finishing could not be obtained, the crystal grain size of the product plate was increased, and the r-average value was decreased. No. In No. 3, since the finishing start temperature was too high, the amount of strain added to the ferrite was small, and recrystallization was difficult to occur, resulting in coarse recovery grains, and the strength, elongation, and r average value were poor.
【００２５】No．４は、仕上圧下率設定が高く、潤滑圧
延で噛み込まず圧延できなかった。No．７は、酸洗後再
度巻き取って、スキンパスを行った例であるが、粗度が
やや粗く、冷延並の表面性状が得られなかった。また、
No．８は、スキンパス圧下率を高くとった場合、No．１
０は低すぎた場合であるが、高すぎると伸びの低下が著
しく、低すぎると粗度が粗かった。No．１２は、巻き取
り時の温度が低かった場合、No．１４は、潤滑が不十分
であった場合であるが、再結晶が不十分、或いは表層の
集合組織改善が不十分で、ｒ平均値が低かった。No. No. 4 had a high finishing reduction ratio setting and could not be rolled because it was not caught in lubrication rolling. No. No. 7 is an example in which after pickling, the film was rewound and skin-passed, but the roughness was rather rough, and the surface texture equivalent to that of cold rolling could not be obtained. Also,
No. No. 8 was No. 8 when the skin pass reduction ratio was high. 1
0 was when it was too low, but when it was too high, the elongation was remarkably lowered, and when it was too low, the roughness was rough. No. No. 12 is No. 12 when the temperature at the time of winding is low. No. 14 was the case where the lubrication was insufficient, but the recrystallization was insufficient, or the texture improvement of the surface layer was insufficient, and the r-average value was low.
【００２６】No．１５は粗圧延と仕上圧延間で９５０℃
で８分保持したものであるがｒ平均値と延性の向上が同
時に達成されている。No．１６は薄手連続鋳造により鋳
片を製造し、ＤＲ工程（鋳片温度を９００℃以下に低下
させない）を経て圧延したものであり、粗圧延と仕上圧
延の間で９５０℃で５分の保持をしたものである。これ
もNo．１５と同様にｒ平均値と延性の向上が同時に達成
されている。その他本発明条件で製造した材料No．６，
９，１１，１３も、良好な材質特性が得られた。No. 15 is 950 ° C between rough rolling and finish rolling
The average value of r and the improvement of ductility were achieved at the same time. No. No. 16 is a product in which a slab is manufactured by thin continuous casting and is rolled through a DR process (the slab temperature is not lowered to 900 ° C. or lower), and is held at 950 ° C. for 5 minutes between rough rolling and finish rolling. It was done. This is also No. Similar to No. 15, improvement in r-average value and ductility was achieved at the same time. Other material No. manufactured under the conditions of the present invention 6,
Good material characteristics were also obtained in 9, 11, and 13.
【００２７】[0027]
【発明の効果】本発明は、成分条件、圧延条件を規制す
ることにより、冷延鋼板に匹敵する絞り性が高く、強度
が高い熱延鋼板を得ることができるようになり、経済的
効果が非常に高い。INDUSTRIAL APPLICABILITY The present invention makes it possible to obtain a hot-rolled steel sheet having high drawability and high strength, which is comparable to that of a cold-rolled steel sheet, by controlling the composition conditions and rolling conditions. Very expensive.
【図１】Ｍｎ量がｒ平均値に及ぼす影響を示した図表。FIG. 1 is a chart showing the influence of Mn amount on r average value.
【図２】ＴＳ，Ｅｌに及ぼすＭｎ量の影響を示した図
表。FIG. 2 is a chart showing the effect of the amount of Mn on TS and El.
【図３】表面粗度に及ぼすスキンパス圧下率の影響を示
した図表。FIG. 3 is a chart showing the effect of skin pass reduction on surface roughness.
【図４】結晶粒径と肌荒れ発生の関係を示した図表。FIG. 4 is a chart showing the relationship between the crystal grain size and the occurrence of rough skin.
Claims (4)
≦２μｍで、その組織がフェライト単相かつ、結晶粒径
≦２０μｍであることを特徴とする熱延高強度鋼板。1. By weight%, 0.003 ≦ C ≦ 0.04%, Si ≦ 0.03%, 1.5 ≦ Mn ≦ 3.0%, P ≦ 0.1%, S ≦ 0.01 %, N ≤ 0.005%, 0.03 ≤ Ti ≤ 0.2%, and 48 (C / 12 + N / 14) ≤ Ti, including other unavoidable elements, and having a surface roughness Ra.
A hot-rolled high-strength steel sheet, wherein ≦ 2 μm, the structure is a ferrite single phase, and the grain size is ≦ 20 μm.
１００℃で加熱した後、９００〜９５０℃で粗圧延を終
了した後、６００〜８００℃の間を各パス１５〜３０％
で摩擦係数μ≦０．１５となるように潤滑を施しながら
圧延を行った後、自己焼鈍または加熱処理によって６５
０〜７５０℃とした後に巻き取り、酸洗に引き続いてス
キンパスによって１〜３％で圧下して巻き取ることを特
徴とする熱延高強度鋼板の製造方法。2. In% by weight, 0.003 ≦ C ≦ 0.04%, Si ≦ 0.03%, 1.5 ≦ Mn ≦ 3.0%, P ≦ 0.1%, S ≦ 0.01 %, N ≤ 0.005%, 0.03 ≤ Ti ≤ 0.2%, and 48 (C / 12 + N / 14) ≤ Ti, and 950 to 1 of steel pieces containing other inevitable elements.
After heating at 100 ℃, after finishing the rough rolling at 900 ~ 950 ℃, each pass 15 ~ 30% between 600 ~ 800 ℃
After being rolled while being lubricated so that the friction coefficient is μ ≦ 0.15, it is reduced to 65 by self-annealing or heat treatment.
A method for producing a hot-rolled high-strength steel sheet, which comprises rolling after setting the temperature to 0 to 750 ° C., pickling, and then rolling by rolling down with a skin pass at 1 to 3%.
１００℃で加熱した後、９００〜９５０℃で粗圧延を終
了した後、９００℃以上で５分以上保持した後、６００
〜８００℃の間を各パス１５〜３０％で摩擦係数μ≦
０．１５となるように潤滑を施しながら圧延を行った
後、自己焼鈍または加熱処理によって６５０〜７５０℃
とした後に巻き取り、酸洗に引き続いてスキンパスによ
って１〜３％で圧下して巻き取ることを特徴とする請求
項２に記載の熱延高強度鋼板の製造方法。3. In weight%, 0.003 ≦ C ≦ 0.04%, Si ≦ 0.03%, 1.5 ≦ Mn ≦ 3.0%, P ≦ 0.1%, S ≦ 0.01 %, N ≤ 0.005%, 0.03 ≤ Ti ≤ 0.2%, and 48 (C / 12 + N / 14) ≤ Ti, and 950 to 1 of steel pieces containing other inevitable elements.
After heating at 100 ° C., finishing rough rolling at 900 to 950 ° C., holding at 900 ° C. or more for 5 minutes or more, and then 600
Coefficient of friction μ ≤ 15% to 30% for each pass between ~ 800 ° C
After rolling while giving lubrication to 0.15, it is 650 to 750 ° C. by self-annealing or heat treatment.
The method for producing a hot-rolled high-strength steel sheet according to claim 2, wherein the hot-rolled high-strength steel sheet is wound up after being rolled up, pickled, and then rolled down with a skin pass at a rate of 1 to 3%.
造し、該鋼片を９００℃以下に温度を低下させることな
く９００〜９５０℃で粗圧延を終了した後、９００℃以
上で５分以上保持した後、６００〜８００℃の間を各パ
ス１５〜３０％で摩擦係数μ≦０．１５となるように潤
滑を施しながら圧延を行った後、自己焼鈍または加熱処
理によって６５０〜７５０℃とした後に巻き取り、酸洗
に引き続いてスキンパスによって１〜３％で圧下して巻
き取ることを特徴とする請求項２に記載の熱延高強度鋼
板の製造方法。4. In% by weight, 0.003 ≦ C ≦ 0.04%, Si ≦ 0.03%, 1.5 ≦ Mn ≦ 3.0%, P ≦ 0.1%, S ≦ 0.01 %, N ≦ 0.005%, 0.03 ≦ Ti ≦ 0.2%, and 48 (C / 12 + N / 14) ≦ Ti, and thin continuous casting of a steel piece containing other inevitable elements, After finishing the rough rolling of the steel slab at 900 to 950 ° C without lowering the temperature to 900 ° C or less, holding the steel slab at 900 ° C or more for 5 minutes or more, and then between 600 to 800 ° C at each pass of 15 to 30%. After rolling while giving lubrication so that the coefficient of friction μ ≦ 0.15, the temperature is adjusted to 650 to 750 ° C. by self-annealing or heat treatment, and then wound, followed by pickling and reduction by 1 to 3% by a skin pass. The hot-rolled high-strength steel sheet according to claim 2, characterized in that Build method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP04282294A JP3231174B2 (en) | 1993-10-18 | 1994-03-14 | Hot-rolled high-strength steel sheet with good drawability and method for producing the same |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP26025693 | 1993-10-18 | ||
| JP5-260256 | 1993-10-18 | ||
| JP04282294A JP3231174B2 (en) | 1993-10-18 | 1994-03-14 | Hot-rolled high-strength steel sheet with good drawability and method for producing the same |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH07166292A true JPH07166292A (en) | 1995-06-27 |
| JP3231174B2 JP3231174B2 (en) | 2001-11-19 |
Family
ID=26382563
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP04282294A Expired - Fee Related JP3231174B2 (en) | 1993-10-18 | 1994-03-14 | Hot-rolled high-strength steel sheet with good drawability and method for producing the same |
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| Country | Link |
|---|---|
| JP (1) | JP3231174B2 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007092134A (en) * | 2005-09-29 | 2007-04-12 | Jfe Steel Kk | Cold-rolled steel sheet excellent in chemical conversion treatment, and manufacturing method therefor |
| CN112888802A (en) * | 2018-10-25 | 2021-06-01 | 杰富意钢铁株式会社 | Ferritic stainless steel hot-rolled annealed steel sheet and method for producing same |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5221554B2 (en) * | 2007-10-19 | 2013-06-26 | 株式会社Ｌｐｔｅｘ | Don't care bit extraction method and don't care bit extraction program |
-
1994
- 1994-03-14 JP JP04282294A patent/JP3231174B2/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007092134A (en) * | 2005-09-29 | 2007-04-12 | Jfe Steel Kk | Cold-rolled steel sheet excellent in chemical conversion treatment, and manufacturing method therefor |
| CN112888802A (en) * | 2018-10-25 | 2021-06-01 | 杰富意钢铁株式会社 | Ferritic stainless steel hot-rolled annealed steel sheet and method for producing same |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3231174B2 (en) | 2001-11-19 |
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