JPS6325055B2 - - Google Patents

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Publication number
JPS6325055B2
JPS6325055B2 JP57155719A JP15571982A JPS6325055B2 JP S6325055 B2 JPS6325055 B2 JP S6325055B2 JP 57155719 A JP57155719 A JP 57155719A JP 15571982 A JP15571982 A JP 15571982A JP S6325055 B2 JPS6325055 B2 JP S6325055B2
Authority
JP
Japan
Prior art keywords
equivalent
cold
less
rolled
steel
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
JP57155719A
Other languages
Japanese (ja)
Other versions
JPS5943825A (en
Inventor
Atsuki Okamoto
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nippon Steel Corp
Original Assignee
Sumitomo Metal Industries Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Sumitomo Metal Industries Ltd filed Critical Sumitomo Metal Industries Ltd
Priority to JP15571982A priority Critical patent/JPS5943825A/en
Publication of JPS5943825A publication Critical patent/JPS5943825A/en
Publication of JPS6325055B2 publication Critical patent/JPS6325055B2/ja
Granted legal-status Critical Current

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Classifications

    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21DMODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/04Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Heat Treatment Of Sheet Steel (AREA)
  • Heat Treatment Of Steel (AREA)

Description

【発明の詳細な説明】[Detailed description of the invention]

この発明は、良好なプレス成形性を備えた冷延
鋼板をコスト安く製造する方法に関するものであ
る。 従来、プレス成形用冷延鋼板を製造するには、
完全凝固した連続鋳造鋳片を切断し冷却した後
に、表面検査、疵除去の処理を施し、ついで1100
〜1300℃に保持された加熱炉に装入して30分〜1
時間の均熱の後熱間圧延し、得られた熱延コイル
をさらに冷間圧延して、焼鈍を施すという工程を
とるのが普通であつた。 ところが、近年に至つて、鋳片表面性状の極め
て良好な連続鋳造方法が開発されるようになつて
きたのに相前後して、省エネルギー思想が増々浸
透し定着してきている中で、連続鋳造スラブを一
旦常温まで冷却することなく熱いうちに加熱炉に
装入し、加熱エネルギーを低減しつつ均熱して熱
間圧延した後、冷間圧延、焼鈍を施すという方法
が採用されるようになつてきた。 ところで、この場合、省エネルギーや作業能率
の観点からは、再加熱のために鋳片を加熱炉へ装
入する工程や、さらには熱間圧延までもを完全に
省略し、鋳片をそのまま冷間圧延することが最も
望ましいものではあるが、このような方法を試み
ようとしても、冷間圧延に供する薄鋳片を安価に
量産する連続鋳造法が未だ確立されていない上
に、例え薄鋳片の量産が確立されたとしても、鋳
片自体は凝固組織を呈しているので、冷間圧延時
強加工を加えると鋼板表面に肌荒れを生じて鋼板
表面の外観を損ねたり、冷延・焼鈍後の冷延鋼材
の絞り性が従来の方法による鋼板よりも劣つてし
まう問題点を解決することができず、結局、実用
化されるに至つていないのが現状であつた。 本発明者等は、上述のような観点から、鋳片の
均熱や熱間圧延を実施することなく、連続鋳造鋳
片をそのまま冷間圧延することによつて、従来法
によるものと同等の良好な表面肌とプレス成形性
を有する冷延鋼板を製造し得る方法を見出すべく
研究を行つた結果、 (a) 鋳造のままの鋼板の表面肌を改善するには、
その鋼板の変形応力を低くし、かつ結晶粒径を
小さくすることが重要であること、 (b) このためには、鋼のC含有量を0.015%(以
下、組成成分量を示す%は重量%とする)以下
とすることによつて、溶鋼から一旦δ相を形成
させ、ついでδ→γ変態をできるだけ低い温度
で起こさせて細いγ粒を生成せしめ、さらにδ
―γ変態時及びγ相に完全に変態してからの粒
成長を抑制するために、適量のTi、Zr、及び
Nbを添加して、鋼中に必然的に存在するNと、
TiN、ZrN、及びNbNを析出するようにして、
凝固鋳片のγ粒の細粒化を図り、これととも
に、式 Ti当量=Ti(%)+48/93Nb(%) +48/91Zr(%) …(1) で表わされるTi当量と、式 C当量=C(%)+12/14N(%) …(2) で表わされるC当量との間に、 (C当量)−1/4(Ti当量)≦0.0010(%) …(3) の関係を満足させ、鋳込組織中に可動転位を形
成させることが重要であり、前記(3)式が満足さ
れないと可動転位密度が小さすぎて鋼の変形が
困難となり、冷間圧延後の鋼板表面には肌荒れ
が発生しやすくなること、 (c) また、一般に、鋳造組織の鋼板中には板面の
法線方向に<100>軸を有した結晶粒が多いが、
従来の冷延鋼板の製造の場合のように、冷延前
に熱間圧延工程があるとこれによつてこの<
100>集合組織が破壊され、熱延後の鋼板にお
いてはほとんど集合組織を示さないランダムな
鋼板となる。したがつてこれを冷間圧延し、板
面法線方向に<111>軸を有する結晶を増し、
ついで再結晶の際にAlNの析出を利用してこ
のような<111>集合組織をさらに増せば、焼
鈍板のr値で示される深絞り性が良好となつて
プレス成形性が向上するのであるが、熱間圧延
工程を省略してしまうと、<100>集合組織を有
した鋼を冷間圧延することになるため、冷延時
における<111>集合組織の発達が不十分で深
絞り性に好ましくない<100>集合組織がかな
り強く残るために、焼鈍板においても<111>
集合組織が弱く<100>集合組織が強くなつて、
深絞り性の劣つたものしか得られなくなる。さ
らに、熱延工程を省略すると冷延前にAlNの
適当の溶体化処理ができないため、上述の従来
法における再結晶の際のAlNの析出を利用し
て<111>集合組織の発達を促進することも困
難となる。 ところが、鋼材が前記(3)式を満足している
と、冷延時に塑性変形が極めて容易となり、冷
間圧延前の鋼板において<100>集合組織が強
かつたとしても、その冷延時に<111>集合組
織が発達し、さらに、焼鈍時においてもAlN
析出物の助けを借りずに<111>集合組織が十
分に発達すること、 以上(a)〜(c)に示す如き知見を得るに至つたので
ある。 この発明は、上記知見に基づいてなされたもの
であつて、 C:0.001〜0.015%、 Mn:0.01〜1.20%、 sol.Al:0.10%以下、 N:0.0060%以下、 を含むとともに、 Ti:0.20%以下、 Nb:0.20%以下、 Zr:0.20%以下、 のうちの1種以上を含有するか、あるいはさら
に、 P:0.03〜0.10%、 Cr:0.05〜1.00%、 B:0.0003〜0.0040%、 Si:0.10〜2.00%、 のうちの1種以上をも含有し、かつ、 Ti当量=Ti(%)+48/93Nb(%) +48/91Zr(%) …(1) C当量=C(%)+12/14N(%) …(2) (C当量)−1/4(Ti当量)≦0.0010(%) …(3) 上記(1)式で計算されるTi当量と、上記(2)式で
計算されるC当量との関係が上記(3)式を満足し、 Fe+不可避不純物:残り、 から成る組成の鋼を、連続鋳造によつて板状鋳片
とし、ついでこれに冷間圧延と、再結晶焼鈍とを
施すことにより、鋳片の再加熱均熱処理や熱間圧
延を施すことなく、プレス成形性に優れた冷延鋼
板を能率良く低コストで製造することに特徴を有
するものである。 ついで、この発明の方法において、鋼の化学成
分組成を上記のとおりに限定した理由を説明す
る。 C C成分は、少なければ少ないほど冷延鋼板製品
のプレス成形性が向上するので好ましいけれど
も、その含有量が0.001%未満では溶製が極めて
困難となり、一方0.015%を越えて含有させると
多くの炭窒化物形成元素を必要とするばかりでな
く、炭窒化物の析出量が多くなつて、最終製品の
プレス成形性が劣化するようになることから、そ
の含有量を0.001〜0.015%と定めた。 Mn Mn成分には、鋼板の靭性を改善する作用があ
るが、その含有量が0.01%未満では靭性改善に所
望の効果が得られず、一方1.20%を越えて含有さ
せると溶製が困難となり、かつコストアツプの原
因ともなることから、その含有量を0.01〜1.20%
と定めた。 sol.Al sol.Alは、脱酸を十分に行つて、炭窒化物形成
元素の歩留向上のために必要に応じて含有される
が、sol.Alを0.10%を越えて含有させてもより一
層の脱酸効果は得られず、コスト高ともなること
から、その上限値を0.10%と定めた。 N N分は、少なければ少ないほどTi当量、すな
わち炭窒化物形成元素の添加含有量が少なくてす
むので好ましい。N含有量が0.0060%を越える
と、特に最終製品におけるプレス成形性が低下す
ることから、その含有量を0.0040%以下と定め
た。 Ti、Nb、及びZr これらの成分には、鋳造板において微細な炭窒
化物を形成して鋳造板における可動転位密度を増
加させ、冷間圧延板の表面性状を改善するととも
に、最終製品における<111>集合組織を形成し
てr値で代表される深絞り性を改善し、プレス成
形性を向上させる作用があるが、それぞれが0.20
%を越えて含有されてもより一層の向上効果が見
られず、コスト高となることから、その上限値を
それぞれTi:0.20%、Nb:0.20%、及びZr:0.20
%と定めた。 また、上記(1)〜(3)式は、固溶〔C+N〕の量を
0.0010(%)以下とし、残りのC+Nを炭窒化物
として析出させるための関係式を示すものであ
る。なお、(C当量)−1/4(Ti当量)の上限値
を0.0010(%)としたのは、この上限値を越える
と、固溶〔C+N〕が多くなつて鋳造板の冷間圧
延板の表面性状及び製品冷延鋼板のプレス成形性
が劣化するようになるからである。さらに、上記
成分は均一に分布させる必要があるが、これは偏
析の少ない連続鋳造急速凝固法を適用することに
よつて可能となる。 P、Cr、B、及びSi これらの成分には、鋼板の強度や材料の均質性
を向上させる作用があるので、必要に応じて含有
されるが、各成分がそれぞれP:0.03%未満、
Cr:0.05%未満、B:0.0003%未満、及びSi:
0.10%未満の含有では所望の向上効果が得られ
ず、一方、それぞれP:0.10%、Cr:1.00%、
B:0.0040%、及びSi:2.00%を越えて含有させ
ると、鋼板の溶接性及び表面性状が劣化するよう
になることから、それぞれの含有量を、P:0.03
〜0.10%、Cr:0.05〜1.00%、B:0.003〜0.0040
%、及びSi:0.10〜2.00%と定めた。 この発明の方法は、上記のような成分組分に鋼
を連続的に板状に鋳造した後、冷間圧延と再結晶
焼鈍とを施すものであるが、連続的に凝固させら
れた鋼板又は鋼板コイルは、当然のことながら表
面疵の除去あるいはスケール除去等の表面状態調
整を施した後に冷間圧延されるものである。そし
て、冷間圧延の圧下率は50%以上が好ましく、圧
下率が大きければ大きいほど得られる製品板のプ
レス成形性が向上する。 また、引続く再結晶焼鈍は、660℃以上の温度
での連続焼鈍あるいは連続溶融メツキなどによつ
て行うのが良い。 ついで、この発明の方法を実施例により比較例
と対比しながら説明する。 実施例 1 C:0.006%、Si:0.01%、Mn:0.08%、P:
0.010%、S:0.001%、sol・Al:0.05%、N:
0.004%を含有し、Tiを0〜0.20%の範囲で変化
させ、Fe:残り、から成る種々の鋼を真空溶解
し、厚さ:10mm、幅:110mm、長さ:100mmの薄鋳
片とした後、直ちに室温まで急冷した。 ついで、この薄鋳片に酸洗を施した後、圧下
率:92%にて冷間圧延を施して0.8mm厚の冷延板
とし、引続いて温度:800℃に90秒保持の条件で
連続焼鈍を施した。そして、冷間圧延板の肌荒れ
発生の有無を調べ、さらに焼鈍した冷延鋼板から
採取したJIS5号引張試験片においてr値及び伸び
を求め、この結果を前記冷延鋼板の固溶C量、す
なわち上記(3)式として示したところの、C当量−
1/4(Ti当量)との関係において第1図に示し
た。 第1図からも明白なように、前記(3)式の値が
0.0010%以下の場合に冷間圧延板の肌荒れを発生
することなく、高いr値を示すとともに、良好な
伸びをも示す冷延鋼板を製造できることがわか
る。 実施例 2 C:0.0040%、Si:0.010%、Mn:0.28%、
P:0.012%、S:0.007%、sol.Al:0.08%、N:
0.0030%、Nb:0.055%、Fe:残り、から成る鋼
Aと、C:0.045%、Si:0.010%、Mn:0.22%、
P:0.011%、S:0.007%、sol.Al:0.051%、
N:0.0032%、Fe:残り、から成る鋼Bとを溶解
後、連続的に急冷凝固させて、厚さ:8mm、幅:
220mmの薄板状コイルとなし、直ちに常温まで急
冷した。 鋼AのTi当量は0.028%、C当量は0.0066%で
あり、前記(3)式を満足するものであるが、鋼Bは
この範囲から外れた比較従来鋼である。 これら2種の鋳造板の表層を研削した後、1.0
mm厚にまで圧下率:87%にて冷間圧延し、ついで
850℃の温度にて30秒の連続焼鈍を行つた。この
場合、冷間圧延板において鋼Aでは肌荒れを生じ
なかつたが、鋼Bでは肌荒れを発生していた。 つぎに、これら焼鈍板を、伸び率:0.6%にて
調質圧延した後、JIS5号引張試験片を採取し、そ
の機械的性質を測定した。この結果を第1表に示
す。
The present invention relates to a method for manufacturing cold-rolled steel sheets with good press formability at low cost. Conventionally, to produce cold rolled steel sheets for press forming,
After cutting and cooling completely solidified continuously cast slabs, surface inspection and flaw removal are performed, and then 1100
Charge the heating furnace at ~1300℃ for 30 minutes~1
It was common practice to perform hot rolling after soaking for a period of time, and then cold-roll the resulting hot-rolled coil and annealing it. However, in recent years, continuous casting methods with extremely good slab surface properties have been developed, but at the same time energy-saving ideas have become increasingly widespread and established, continuous casting slabs A method has come to be adopted in which the steel is charged into a heating furnace while still hot without being cooled to room temperature, soaked and hot-rolled while reducing heating energy, and then cold-rolled and annealed. Ta. By the way, in this case, from the viewpoint of energy saving and work efficiency, the step of charging the slab into a heating furnace for reheating and even hot rolling can be completely omitted, and the slab can be directly rolled into cold. Although rolling is the most desirable method, even if such a method is attempted, a continuous casting method for inexpensively mass-producing thin slabs for cold rolling has not yet been established, and even if thin slabs are Even if mass production has been established, the slab itself has a solidified structure, so if heavy working is applied during cold rolling, the surface of the steel plate will become rough and the appearance of the steel plate surface will be damaged, and the appearance of the steel plate surface may be damaged after cold rolling or annealing. However, it has not been possible to solve the problem that the drawability of the cold-rolled steel material is inferior to that of steel sheets produced by conventional methods, and as a result, it has not been put into practical use. From the above-mentioned viewpoint, the inventors of the present invention have achieved the same results as those achieved by the conventional method by cold-rolling continuously cast slabs as they are without soaking or hot rolling the slabs. As a result of conducting research to find a method for manufacturing cold-rolled steel sheets with good surface texture and press formability, we found that (a) To improve the surface texture of as-cast steel sheets,
It is important to lower the deformation stress of the steel plate and reduce the grain size. %) or less, the δ phase is formed from the molten steel, and then the δ → γ transformation occurs at the lowest possible temperature to generate thin γ grains, and then the δ
-In order to suppress grain growth during γ transformation and after complete transformation to γ phase, appropriate amounts of Ti, Zr, and
By adding Nb, the N that naturally exists in steel,
By precipitating TiN, ZrN, and NbN,
We aim to make the γ grains of the solidified slab finer, and at the same time, the Ti equivalent expressed by the formula Ti equivalent = Ti (%) + 48/93Nb (%) + 48/91 Zr (%) ... (1) and the formula C equivalent = C (%) + 12/14 N (%) ... (2) Satisfies the relationship of (C equivalent) - 1/4 (Ti equivalent) ≦ 0.0010 (%) ... (3) It is important to form mobile dislocations in the cast structure, and if the above equation (3) is not satisfied, the mobile dislocation density will be too small and it will be difficult to deform the steel. (c) In general, steel sheets with a cast structure have many crystal grains with <100> axes in the normal direction of the sheet surface;
As in the production of conventional cold rolled steel sheets, if there is a hot rolling step before cold rolling, this
100> The texture is destroyed, and the steel plate after hot rolling becomes a random steel plate that shows almost no texture. Therefore, this is cold rolled to increase the number of crystals with <111> axis in the normal direction of the plate surface,
If the <111> texture is then further increased by utilizing the precipitation of AlN during recrystallization, the deep drawability indicated by the r value of the annealed plate will become better and the press formability will improve. However, if the hot rolling process is omitted, steel with a <100> texture will be cold rolled, resulting in insufficient development of the <111> texture during cold rolling, resulting in poor deep drawability. Because the undesirable <100> texture remains quite strong, <111> texture remains even in annealed plates.
The texture is weak and the <100> texture is strong,
Only products with poor deep drawability can be obtained. Furthermore, if the hot rolling process is omitted, appropriate solution treatment of AlN cannot be performed before cold rolling, so the precipitation of AlN during recrystallization in the conventional method described above is utilized to promote the development of the <111> texture. It also becomes difficult. However, if the steel material satisfies the above formula (3), plastic deformation becomes extremely easy during cold rolling, and even if the <100> texture is strong in the steel sheet before cold rolling, < 111>The texture is developed, and even during annealing, AlN
We have come to the knowledge shown in (a) to (c) above that the <111> texture develops sufficiently without the aid of precipitates. This invention was made based on the above findings, and contains C: 0.001 to 0.015%, Mn: 0.01 to 1.20%, sol.Al: 0.10% or less, N: 0.0060% or less, and Ti: 0.20% or less, Nb: 0.20% or less, Zr: 0.20% or less, or further contains one or more of the following: P: 0.03 to 0.10%, Cr: 0.05 to 1.00%, B: 0.0003 to 0.0040% , Si: 0.10 to 2.00%, and also contains one or more of the following, Ti equivalent = Ti (%) + 48/93Nb (%) + 48/91Zr (%) ... (1) C equivalent = C (%) ) + 12/14N (%) ...(2) (C equivalent) - 1/4 (Ti equivalent) ≦ 0.0010 (%) ... (3) Ti equivalent calculated by the above formula (1) and the above formula (2) The relationship with the C equivalent calculated by satisfies the above formula (3), Fe + unavoidable impurities: the remainder, steel is made into a plate-shaped slab by continuous casting, and then cold-rolled. It is characterized by the ability to efficiently produce cold-rolled steel sheets with excellent press formability at low cost by performing recrystallization annealing and without reheating and soaking the slab or hot rolling. be. Next, the reason why the chemical composition of the steel is limited as described above in the method of the present invention will be explained. The smaller the C component is, the better the press formability of the cold rolled steel sheet product will be, so it is preferable; however, if the content is less than 0.001%, it will be extremely difficult to produce, while if the content exceeds 0.015%, many Not only is a carbonitride-forming element required, but the amount of carbonitride precipitation increases and the press formability of the final product deteriorates, so the content was set at 0.001 to 0.015%. . Mn The Mn component has the effect of improving the toughness of steel sheets, but if the content is less than 0.01%, the desired effect in improving toughness cannot be obtained, while if the content exceeds 1.20%, melting becomes difficult. , and also cause cost increases, the content should be reduced to 0.01-1.20%.
It was determined that sol.Al sol.Al is contained as necessary to perform sufficient deoxidation and improve the yield of carbonitride-forming elements, but even if sol.Al is contained in excess of 0.10%, Since further deoxidizing effects cannot be obtained and the cost increases, the upper limit was set at 0.10%. N The smaller the N content, the less the Ti equivalent, ie, the added content of carbonitride-forming elements, is preferable. If the N content exceeds 0.0060%, press formability particularly in the final product deteriorates, so the content was set at 0.0040% or less. Ti, Nb, and Zr These components form fine carbonitrides in the cast sheet, increase the mobile dislocation density in the cast sheet, improve the surface properties of the cold rolled sheet, and improve the surface quality of the final product. 111>It has the effect of forming a texture, improving deep drawability represented by the r value, and improving press formability, but each has an effect of 0.20
Even if the content exceeds 0.2%, no further improvement effect will be seen and the cost will increase, so the upper limit values were set to 0.20% for Ti, 0.20% for Nb, and 0.20% for Zr, respectively.
%. In addition, the above equations (1) to (3) calculate the amount of solid solution [C+N].
0.0010 (%) or less, and shows a relational expression for precipitating the remaining C+N as carbonitride. The upper limit of (C equivalent) - 1/4 (Ti equivalent) is set to 0.0010 (%) because if this upper limit is exceeded, the solid solution [C + N] will increase and the cold rolled plate of the cast plate will deteriorate. This is because the surface quality of the product and the press formability of the product cold-rolled steel sheet deteriorate. Furthermore, it is necessary to uniformly distribute the above-mentioned components, which can be achieved by applying a continuous casting rapid solidification method with less segregation. P, Cr, B, and Si These components have the effect of improving the strength of the steel sheet and the homogeneity of the material, so they are included as necessary, but each component is P: less than 0.03%,
Cr: less than 0.05%, B: less than 0.0003%, and Si:
If the content is less than 0.10%, the desired improvement effect cannot be obtained; on the other hand, P: 0.10%, Cr: 1.00%,
If the content exceeds B: 0.0040% and Si: 2.00%, the weldability and surface quality of the steel plate will deteriorate, so the respective contents should be set to P: 0.03%.
~0.10%, Cr: 0.05~1.00%, B: 0.003~0.0040
%, and Si: 0.10 to 2.00%. The method of this invention involves continuously casting steel into a plate shape having the above-mentioned component composition, and then subjecting it to cold rolling and recrystallization annealing. Naturally, the steel plate coil is cold-rolled after surface condition adjustment such as removal of surface flaws or scale removal. The reduction ratio in cold rolling is preferably 50% or more, and the larger the reduction ratio, the better the press formability of the resulting product sheet. Further, the subsequent recrystallization annealing is preferably performed by continuous annealing at a temperature of 660° C. or higher, continuous melt plating, or the like. Next, the method of the present invention will be explained using examples and comparing with comparative examples. Example 1 C: 0.006%, Si: 0.01%, Mn: 0.08%, P:
0.010%, S: 0.001%, sol・Al: 0.05%, N:
Various steels containing 0.004%, Ti varying in the range of 0 to 0.20%, and Fe: the rest were vacuum melted to form thin slabs of thickness: 10 mm, width: 110 mm, and length: 100 mm. After that, the mixture was immediately cooled down to room temperature. Next, after pickling this thin slab, it was cold rolled at a reduction rate of 92% to form a cold rolled plate with a thickness of 0.8 mm, and then maintained at a temperature of 800°C for 90 seconds. Continuous annealing was performed. Then, the presence or absence of surface roughness of the cold-rolled steel sheet was examined, and the r value and elongation were determined using a JIS No. 5 tensile test piece taken from the annealed cold-rolled steel sheet. As shown in the above formula (3), the C equivalent -
The relationship with 1/4 (Ti equivalent) is shown in FIG. As is clear from Figure 1, the value of equation (3) above is
It can be seen that when the content is 0.0010% or less, it is possible to produce a cold-rolled steel sheet that exhibits a high r value and good elongation without causing surface roughness of the cold-rolled sheet. Example 2 C: 0.0040%, Si: 0.010%, Mn: 0.28%,
P: 0.012%, S: 0.007%, sol.Al: 0.08%, N:
Steel A consisting of 0.0030%, Nb: 0.055%, Fe: remainder, C: 0.045%, Si: 0.010%, Mn: 0.22%,
P: 0.011%, S: 0.007%, sol.Al: 0.051%,
After melting Steel B consisting of N: 0.0032% and Fe: the remainder, it was continuously rapidly solidified to a thickness of 8 mm and a width of 8 mm.
A 220 mm thin plate coil was prepared and immediately quenched to room temperature. Steel A has a Ti equivalent of 0.028% and a C equivalent of 0.0066%, which satisfy the above formula (3), but Steel B is a comparative conventional steel that falls outside of this range. After grinding the surface layer of these two types of cast plates, 1.0
Cold rolled to a thickness of mm at a reduction rate of 87%, then
Continuous annealing was performed at a temperature of 850°C for 30 seconds. In this case, steel A did not experience rough skin in the cold rolled sheet, but steel B did experience rough skin. Next, these annealed plates were temper rolled at an elongation rate of 0.6%, and then JIS No. 5 tensile test pieces were taken and their mechanical properties were measured. The results are shown in Table 1.

【表】 第1表に示されるように、鋼Aを使用する本発
明方法によつて製造された冷延鋼板は、鋼Bを使
用したものに比べて、r値が高く、伸びも良好
で、プレス成形性に優れていることが明らかであ
る。 実施例 3 第2表に示す成分組成の鋼を真空溶解し、厚
さ:40mm、幅:220mm、長さ:440mmの薄鋳片とし
た後、直ちに室温まで冷却した。 これらの鋳片について、スケールを切削除去
後、1.2mm厚にまで圧下率:97%にて冷間圧延す
るとともに、温度:800℃にて90秒保持の条件で
の連続焼鈍を行うことによつて、本発明冷延鋼板
1〜20、及び比較冷延鋼板21〜25をそれぞれ製造
した。なお、比較冷延鋼板21〜25は、いずれも成
分組成がこの発明の範囲から外れたものであり、
第2表には該当するものに※印を付してある。 つぎに、この結果得られた本発明冷延鋼板1〜
20及び比較冷延鋼板21〜25について、引張特性及
びr値を測定し、この結果を第2表に併せて示し
た。 第2表に示されるように、本発明冷延鋼板1〜
20は、いずれも良好な伸び及び高r値、すなわ
ち、良好なプレス成形性を有するのに対して、比
較冷延鋼板21及び22は(C当量)−1/4(Ti
[Table] As shown in Table 1, cold-rolled steel sheets manufactured by the method of the present invention using Steel A have a higher r value and better elongation than those using Steel B. It is clear that the material has excellent press formability. Example 3 Steel having the composition shown in Table 2 was melted in vacuum to form a thin slab with a thickness of 40 mm, a width of 220 mm, and a length of 440 mm, and then immediately cooled to room temperature. After removing the scale, these slabs were cold-rolled to a thickness of 1.2 mm at a reduction rate of 97% and continuously annealed at a temperature of 800°C for 90 seconds. Thus, cold rolled steel sheets 1 to 20 of the present invention and comparative cold rolled steel sheets 21 to 25 were manufactured, respectively. In addition, comparative cold-rolled steel sheets 21 to 25 all have compositions that are outside the scope of the present invention,
In Table 2, applicable items are marked with *. Next, the cold rolled steel sheets 1 to 1 of the present invention obtained as a result
The tensile properties and r-values of No. 20 and comparative cold-rolled steel sheets No. 21 to No. 25 were measured, and the results are also shown in Table 2. As shown in Table 2, cold rolled steel sheets 1 to 1 of the present invention
20 both have good elongation and high r value, that is, good press formability, whereas comparative cold rolled steel sheets 21 and 22 have (C equivalent) -1/4 (Ti

【表】【table】

【表】 当量)がそれぞれこの発明の範囲を越えて高いた
めに、冷延板において肌荒れが発生しており、さ
らに製品の特性値はr値と伸びが低く、プレス成
形性に劣ることを示している。 また、比較冷延鋼板23及び25は、(C当量)−1/
4(Ti当量)が低いために冷延板における肌荒れ
発生は無いが、比較冷延鋼板23ではC量が、また
比較冷延鋼板25ではN量が本発明の範囲よりも高
いため、伸び及びr値が劣つている。 さらに、比較冷延鋼板24は炭窒化物形成元素を
含有しない通常のP添加Alキルド鋼板であるた
め、冷間圧延鋼板製品の伸び及びr値とも低くな
つている。 実施例 4 C:0.0030%、Si:0.20%、Mn:1.10%、P:
0.080%、S:0.007%、sol.Al:0.07%、N:
0.0025%、Ti:0.020%、Nb:0.012%、Fe:残
り、からなる鋼を溶解後、連続的に急冷凝固させ
て、厚さ:2mm、幅:220mmの薄板状コイルとな
し、直ちに常温まで急冷した。なお、この鋼は、
Ti当量:0.0262%、C当量:0.0051%であり、前
記(3)式を満足するものである。 ついで、このコイルに、酸洗により表面スケー
ルを除いた後、0.6mmの厚さまで70%の圧下率で
冷間圧延を施し、引続いて温度:850℃に30秒間
保持の条件で連続焼鈍を行ない、さらに伸び率:
0.2%で調質圧延を行なつた後、JIS5号の引張試
験片を採取し、その機械的性質を測定した。その
結果を第3表に示す。
[Table] Because the values (equivalent weight) are higher than the range of this invention, roughness has occurred in the cold-rolled sheet, and the characteristic values of the product are low r value and elongation, indicating poor press formability. ing. In addition, comparative cold-rolled steel sheets 23 and 25 have (C equivalent) −1/
4 (Ti equivalent) is low, so there is no occurrence of surface roughness in cold-rolled sheets. The r value is poor. Furthermore, since the comparative cold-rolled steel sheet 24 is a normal P-added Al-killed steel sheet that does not contain carbonitride-forming elements, the elongation and r value of the cold-rolled steel sheet product are both low. Example 4 C: 0.0030%, Si: 0.20%, Mn: 1.10%, P:
0.080%, S: 0.007%, sol.Al: 0.07%, N:
After melting the steel consisting of 0.0025%, Ti: 0.020%, Nb: 0.012%, and Fe: the remainder, it is continuously rapidly solidified to form a thin plate coil with a thickness of 2 mm and a width of 220 mm, which is immediately brought to room temperature. It was rapidly cooled. Furthermore, this steel is
Ti equivalent: 0.0262%, C equivalent: 0.0051%, which satisfy the above formula (3). Next, this coil was subjected to pickling to remove surface scale, then cold rolled at a reduction rate of 70% to a thickness of 0.6 mm, and then continuously annealed at a temperature of 850°C for 30 seconds. Further growth rate:
After temper rolling at 0.2%, JIS No. 5 tensile test pieces were taken and their mechanical properties were measured. The results are shown in Table 3.

【表】 第3表に示されるように、本発明方法による冷
延鋼板は高張力のわりにプレス成形性が良好なこ
とが明らかである。 上述のように、この発明によれば、良好なプレ
ス成形性をもつた冷延鋼板を、エネルギー消費量
を最少限に抑えるとともに、熱間圧延設備を省略
してコスト安く、高能率で製造することができる
など、工業上有用な効果がもたらされるのであ
る。
[Table] As shown in Table 3, it is clear that the cold rolled steel sheet produced by the method of the present invention has good press formability despite its high tensile strength. As described above, according to the present invention, a cold-rolled steel sheet with good press formability can be manufactured at low cost and with high efficiency by minimizing energy consumption and omitting hot rolling equipment. This brings about industrially useful effects such as the ability to

【図面の簡単な説明】[Brief explanation of the drawing]

第1図は、冷延鋼板中の(C当量)−1/4(Ti
当量)の値が冷延板の肌荒れ発生状況及び製品の
伸び、並びにr値に及ぼす影響を示した線図であ
る。
Figure 1 shows (C equivalent) -1/4 (Ti
FIG. 2 is a diagram showing the influence of the value of (equivalent weight) on the appearance of rough skin of a cold-rolled sheet, the elongation of the product, and the r value.

Claims (1)

【特許請求の範囲】 1 C:0.001〜0.015%、 Mn:0.01〜1.20%、 Sol.Al:0.10%以下、 N:0.0060%以下、 を含むとともに、 Ti:0.20%以下、 Nb:0.20%以下、 Zr:0.20%以下、 のうちの1種以上を含有し、かつ、 Ti当量=Ti(%)+48/93Nb(%) +48/91Zr(%) …(1) C当量=C(%)+12/14N(%) …(2) (C当量)−1/4(Ti当量)≦0.0010(%) …(3) 上記(1)式で計算されるTi当量と、上記(2)式で
計算されるC当量との関係が上記(3)式を満足し、 Fe+不可避不純物:残り から成る組成(以上重量%)の鋼を、連続鋳造に
よつて板状鋳片とし、ついでこれに冷間圧延と、
再結晶焼鈍とを施すことを特徴とするプレス成形
用冷延鋼板の製造法。 2 C:0.001〜0.015%、 Mn:0.01〜1.20%、 sol.Al:0.10%以下、 N:0.0060%以下、 を含むとともに、 Ti:0.20%以下、 Nb:0.20%以下、 Zr:0.20%以下、 のうちの1種以上を含有し、さらに、 P:0.03〜0.10%、 Cr:0.05〜1.00%、 B:0.0003〜0.0040%、 Si:0.10〜2.00%、 のうちの1種以上をも含有し、かつ、 Ti当量=Ti(%)+48/93Nb(%) +48/91Zr(%) …(1) C当量=C(%)+12/14N(%) …(2) (C当量)−1/4(Ti当量)≦0.0010(%) …(3) 上記(1)式で計算されるTi当量と、上記(2)式で
計算されるC当量との関係が上記(3)式を満足し、 Fe+不可避不純物:残り から成る組成(以上重量%)の鋼を、連続鋳造に
よつて板状鋳片とし、ついでこれに冷間圧延と、
再結晶焼鈍とを施すことを特徴とするプレス成形
用冷延鋼板の製造法。
[Claims] 1 C: 0.001 to 0.015%, Mn: 0.01 to 1.20%, Sol.Al: 0.10% or less, N: 0.0060% or less, Ti: 0.20% or less, Nb: 0.20% or less , Zr: 0.20% or less, contains one or more of the following, and Ti equivalent = Ti (%) + 48/93Nb (%) + 48/91 Zr (%) ... (1) C equivalent = C (%) + 12 /14N (%) ... (2) (C equivalent) - 1/4 (Ti equivalent) ≦ 0.0010 (%) ... (3) Ti equivalent calculated by the above formula (1) and calculated by the above formula (2) A steel having a composition (by weight % above) of Fe + unavoidable impurities and the balance satisfying the above equation (3) with the C equivalent is continuously cast into a plate slab, and then cold cast. rolling and
A method for producing a cold-rolled steel sheet for press forming, characterized by subjecting it to recrystallization annealing. 2 Contains C: 0.001~0.015%, Mn: 0.01~1.20%, sol.Al: 0.10% or less, N: 0.0060% or less, Ti: 0.20% or less, Nb: 0.20% or less, Zr: 0.20% or less , and further contains one or more of the following: P: 0.03 to 0.10%, Cr: 0.05 to 1.00%, B: 0.0003 to 0.0040%, Si: 0.10 to 2.00%. And, Ti equivalent = Ti (%) + 48/93Nb (%) + 48/91Zr (%) ... (1) C equivalent = C (%) + 12/14 N (%) ... (2) (C equivalent) - 1 /4 (Ti equivalent)≦0.0010 (%) ...(3) The relationship between the Ti equivalent calculated by the above formula (1) and the C equivalent calculated by the above formula (2) satisfies the above formula (3) Then, steel with a composition (more than % by weight) consisting of Fe + unavoidable impurities and the remainder is made into a plate-shaped slab by continuous casting, and then cold-rolled.
A method for producing a cold-rolled steel sheet for press forming, characterized by subjecting it to recrystallization annealing.
JP15571982A 1982-09-07 1982-09-07 Manufacture of cold rolled steel plate for press forming Granted JPS5943825A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP15571982A JPS5943825A (en) 1982-09-07 1982-09-07 Manufacture of cold rolled steel plate for press forming

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP15571982A JPS5943825A (en) 1982-09-07 1982-09-07 Manufacture of cold rolled steel plate for press forming

Publications (2)

Publication Number Publication Date
JPS5943825A JPS5943825A (en) 1984-03-12
JPS6325055B2 true JPS6325055B2 (en) 1988-05-24

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Country Link
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Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS59177327A (en) * 1983-03-25 1984-10-08 Sumitomo Metal Ind Ltd Production of cold rolled steel sheet for pressing work
JPH0639619B2 (en) * 1984-10-08 1994-05-25 新日本製鐵株式会社 Method for manufacturing thin steel sheet with excellent formability
JPH0639621B2 (en) * 1984-11-30 1994-05-25 新日本製鐵株式会社 Method for manufacturing thin steel sheet with excellent formability
JPH0639620B2 (en) * 1984-11-30 1994-05-25 新日本製鐵株式会社 Method for manufacturing thin steel sheet with excellent formability
JPS61133322A (en) * 1984-11-30 1986-06-20 Nippon Steel Corp Production of thin steel sheet having excellent formability
JPH0756049B2 (en) * 1986-03-04 1995-06-14 新日本製鐵株式会社 Manufacturing method of high strength cold rolled steel sheet
JPH0756052B2 (en) * 1986-04-21 1995-06-14 新日本製鐵株式会社 Manufacturing method of cold rolled steel sheet for processing

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS53115610A (en) * 1977-03-19 1978-10-09 Nippon Steel Corp Method for manufacturing cold drawn steel strip for use in deep drawing
JPS5573826A (en) * 1978-11-24 1980-06-03 Nisshin Steel Co Ltd Production of alloyed-zinc-plated steel plate for deep drawing
JPS5573825A (en) * 1978-11-24 1980-06-03 Nisshin Steel Co Ltd Production of hot-dipped steel plate for ultra-deep drawing
JPS55115928A (en) * 1979-02-27 1980-09-06 Kawasaki Steel Corp Production of non-aging cold rolled steel plate of excellent deep drawability
JPS55141526A (en) * 1979-04-18 1980-11-05 Kawasaki Steel Corp Production of high tension cold-rolled steel plate for deep drawing
JPS5680358A (en) * 1979-12-03 1981-07-01 Hitachi Ltd Method and apparatus for continuous production of sheet

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS53115610A (en) * 1977-03-19 1978-10-09 Nippon Steel Corp Method for manufacturing cold drawn steel strip for use in deep drawing
JPS5573826A (en) * 1978-11-24 1980-06-03 Nisshin Steel Co Ltd Production of alloyed-zinc-plated steel plate for deep drawing
JPS5573825A (en) * 1978-11-24 1980-06-03 Nisshin Steel Co Ltd Production of hot-dipped steel plate for ultra-deep drawing
JPS55115928A (en) * 1979-02-27 1980-09-06 Kawasaki Steel Corp Production of non-aging cold rolled steel plate of excellent deep drawability
JPS55141526A (en) * 1979-04-18 1980-11-05 Kawasaki Steel Corp Production of high tension cold-rolled steel plate for deep drawing
JPS5680358A (en) * 1979-12-03 1981-07-01 Hitachi Ltd Method and apparatus for continuous production of sheet

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