JP3043883B2 - Method for producing high-strength cold-rolled steel sheet and galvanized steel sheet with excellent deep drawability - Google Patents
Method for producing high-strength cold-rolled steel sheet and galvanized steel sheet with excellent deep drawabilityInfo
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- JP3043883B2 JP3043883B2 JP4038008A JP3800892A JP3043883B2 JP 3043883 B2 JP3043883 B2 JP 3043883B2 JP 4038008 A JP4038008 A JP 4038008A JP 3800892 A JP3800892 A JP 3800892A JP 3043883 B2 JP3043883 B2 JP 3043883B2
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Description
【０００１】[0001]
【産業上の利用分野】この発明は、自動車用鋼板等の使
途に用いて有用な、深絞り性に優れた高強度冷延鋼板及
び亜鉛めっき鋼板の製造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 high-strength cold-rolled steel sheet and a galvanized steel sheet having excellent deep drawability, which is useful for use in automotive steel sheets and the like.
【０００２】[0002]
【従来の技術】自動車のパネル等に使用される冷延鋼板
には、優れた深絞り性が要求される。このように鋼板が
優れた深絞り性を示すためには、鋼板の機械的特性とし
て、高いｒ値（ランクフォード値）と良好な延性（El.
）とをそなえていることが必要である。2. Description of the Related Art Cold-rolled steel sheets used for automobile panels and the like are required to have excellent deep drawability. In order for the steel sheet to exhibit excellent deep drawability as described above, as the mechanical properties of the steel sheet, a high r value (Rankford value) and a good ductility (El.
) Is necessary.
【０００３】深絞り性の改善のためには各種の方法が提
案されている。例えば特公昭44-17268号公報、特公昭44
-17269号公報及び特公昭44-17270号公報には、低炭素リ
ムド鋼に２回冷延−焼鈍を施すことにより、ｒ値を2.18
まで高めた冷延鋼板の製造方法が開示されている。しか
しながらこれらの方法は、冷間圧延と再結晶焼鈍とを２
回ずつ行わなければならず、そのために要するエネルギ
ー及びコストは莫大なものとなる。。Various methods have been proposed for improving the deep drawability. For example, JP-B-44-17268, JP-B-44-17268
No. -17269 and Japanese Patent Publication No. Sho 44-17270, low-carbon rimmed steel is subjected to cold-rolling-annealing twice to increase the r value to 2.18.
A method for producing a cold-rolled steel sheet having an increased temperature is disclosed. However, these methods involve two steps of cold rolling and recrystallization annealing.
It has to be done every time, and the energy and cost required for it are enormous. .
【０００４】一方、近年になって自動車の車体軽量化及
び安全性向上を目的として、引張強さが35〜60kgf/mm2
の如き、より高強度の鋼板を用いようとする機運が急速
に高まってきた。このように高強度の鋼板であっても、
プレス成形の際は、優れた深絞り性を示すことが要求さ
れることは言うまでもなく、したがって、より高強度で
かつ従来鋼と比べても同等以上の高いｒ値と優れた延性
とをそなえる鋼板について研究開発が進められている。On the other hand, in recent years, for the purpose of reducing the weight of a vehicle body and improving safety, a tensile strength of 35 to 60 kgf / mm 2 has been used.
The momentum for using higher strength steel sheets has rapidly increased. Even with such a high-strength steel sheet,
It is needless to say that during press forming, it is required to exhibit excellent deep drawability, and therefore, a steel plate having higher strength and a r value equal to or higher than that of conventional steel and excellent ductility. R & D is progressing.
【０００５】このような深絞り用高強度冷延鋼板の製造
には、Si、Mn、Ｐ等を強化成分として含有させた低炭素
Alキルド鋼を、通常の熱間圧延を施した後に冷間圧延を
行い、引き続き再結晶焼鈍を施すことが一般的であっ
た。しかしながら、高強度を得るためには上記の強化成
分を多量に含有させなければならず、そのため深絞り性
に好ましくない集合組織が形成され、ｒ値の低い鋼板し
か得られていなかった。[0005] In order to manufacture such a high-strength cold-rolled steel sheet for deep drawing, a low-carbon steel containing Si, Mn, P, etc. as a reinforcing component is used.
Generally, Al-killed steel is subjected to ordinary hot rolling, then to cold rolling, and subsequently to recrystallization annealing. However, in order to obtain high strength, a large amount of the above-described reinforcing component must be contained, and therefore, a texture that is not favorable for deep drawability is formed, and only a steel sheet having a low r-value has been obtained.
【０００６】[0006]
【発明が解決しようとする課題】この発明は、上記の問
題を有利に解決するもので、鋼成分及び製造条件を規制
することにより、従来よりも格段に優れた深絞り性を有
する高強度冷延鋼板及びこの冷延鋼板を用いた亜鉛めっ
き鋼板を製造できる方法を提案することを目的とする。SUMMARY OF THE INVENTION The present invention advantageously solves the above-mentioned problems and regulates the steel composition and production conditions to provide a high-strength cold-drawing material having a much better deep drawability than before. It is an object of the present invention to propose a method for manufacturing a rolled steel sheet and a galvanized steel sheet using the cold-rolled steel sheet.
【０００７】[0007]
【課題を解決するための手段】発明者らは、深絞り性を
向上させるべく鋭意研究を重ねた結果、以下のように鋼
成分及び製造条件を限定することにより、優れた深絞り
性を有する高強度冷延鋼板が得られることを見出した。Means for Solving the Problems The inventors of the present invention have made intensive studies to improve the deep drawability, and as a result, have excellent deep drawability by limiting the steel composition and production conditions as follows. It has been found that a high-strength cold-rolled steel sheet can be obtained.
【０００８】この発明の要旨は次のとおりである。 (1) Ｃ：0.01wt％以下、Si：0.5 〜1.5 wt％、Mn：3.0
wt％以下、Ti：0.01〜0.2 wt％、Nb：0.001 〜0.2 wt
％、Ｂ：0.0001〜0.0020wt％、Al：0.01〜0.20wt％、
Ｐ：0.03〜0.20wt％、Ｓ：0.05wt％以下及びＮ：0.01wt
％以下を含み、かつ上記Ｃ，Ti及びＮの各含有量
〔Ｃ〕，〔Ti〕及び〔Ｎ〕が次式〔Ti〕≧48（〔Ｃ〕／
12＋〔Ｎ〕／14）（wt％）を満足する基本成分組成にな
り、残部はFe及び不可避的不純物よりなる鋼素材を、Ar
3 変態点以下500 ℃以上の温度域にて潤滑を施しつつ、
合計圧下率が50％以上95％以下になる圧延加工を施し、
次いで巻取又は焼鈍工程により再結晶処理を施した後、
圧下率50〜95％の冷間圧延を施し、引き続き再結晶焼鈍
を施すことを特徴とする、深絞り性に優れた高強度冷延
鋼板の製造方法（第１発明）。The gist of the present invention is as follows. (1) C: 0.01 wt% or less, Si: 0.5 to 1.5 wt%, Mn: 3.0
wt% or less, Ti: 0.01 to 0.2 wt%, Nb: 0.001 to 0.2 wt
%, B: 0.0001 to 0.0020 wt%, Al: 0.01 to 0.20 wt%,
P: 0.03 to 0.20 wt%, S: 0.05 wt% or less and N: 0.01 wt%
% And the respective contents of C, Ti and N [C], [Ti] and [N] are represented by the following formula [Ti] ≧ 48 ([C] /
12+ [N] / 14) (wt%), and the balance was steel material consisting of Fe and unavoidable impurities.
3 While lubricating in the temperature range below the transformation point and above 500 ° C,
Rolling process that the total draft is 50% or more and 95% or less,
Then, after performing a recrystallization treatment by a winding or annealing process,
A method for producing a high-strength cold-rolled steel sheet excellent in deep drawability, characterized by performing cold rolling at a reduction ratio of 50 to 95% and subsequently performing recrystallization annealing (first invention).
【０００９】(2) 第１発明の鋼成分に加えてMo：0.01〜
1.0 wt％を含有する深絞り性に優れた高強度冷延鋼板の
製造方法（第２発明）。(2) In addition to the steel component of the first invention, Mo: 0.01 to
A method for producing a high-strength cold-rolled steel sheet containing 1.0 wt% and having excellent deep drawability (second invention).
【００１０】(3) 第１発明又は第２発明の鋼成分に加え
てCu：0.1 〜1.5 wt％、Ni：0.1 〜1.5 wt％を含有する
深絞り性に優れた高強度冷延鋼板の製造方法（第３発
明）。(3) Production of a high-strength cold-rolled steel sheet which is excellent in deep drawability and contains 0.1 to 1.5 wt% of Cu and 0.1 to 1.5 wt% of Ni in addition to the steel component of the first or second invention. Method (third invention).
【００１１】(4) 第１発明、第２発明又は第３発明にお
ける冷間圧延後の再結晶焼鈍が連続溶融亜鉛めっきライ
ンで行うものである深絞り性に優れた高強度亜鉛めっき
鋼板の製造方法（第４発明）。(4) Production of a high strength galvanized steel sheet excellent in deep drawability, wherein the recrystallization annealing after cold rolling in the first invention, the second invention or the third invention is performed in a continuous galvanizing line. Method (4th invention).
【００１２】以下、この発明を開発する基礎となった研
究結果について述べる。 Si：0.5 wt％、Mn：0.5 wt％、Ｐ：0.06wt％、Ｓ：0.01
wt％、Al：0.05wt％、Ｎ：0.002 wt％、Nb：0.001 wt％
及びＢ：0.001 wt％を含み、Ｃ及びTiを、Ｃ：0.001 〜
0.01wt％、Ti：0.01〜0.2 wt％の範囲で種々に変化させ
て含有し、残部は実質的にFeの組成の熱延鋼帯を、700
℃に加熱均熱後、１パスで60％の潤滑圧延を行った。そ
の後酸洗し、冷間圧延を圧下率75％で施して板厚0.7 mm
とした後、再結晶焼鈍を850 ℃、20 sの条件で行い供試
鋼とした。Hereinafter, the results of the research on which the present invention was developed will be described. Si: 0.5 wt%, Mn: 0.5 wt%, P: 0.06 wt%, S: 0.01
wt%, Al: 0.05 wt%, N: 0.002 wt%, Nb: 0.001 wt%
And B: 0.001 wt%, containing C and Ti, C: 0.001 to
0.01 wt%, Ti: contained variously changed in the range of 0.01 to 0.2 wt%, and the balance is a hot-rolled steel strip having a substantially Fe composition of 700%.
After heating and soaking at ℃, lubrication rolling of 60% was performed in one pass. After that, it is pickled and cold-rolled at a reduction of 75% to a thickness of 0.7 mm.
After that, recrystallization annealing was performed at 850 ° C. for 20 s to obtain a test steel.
【００１３】かくして得られた供試鋼の、ｒ値に及ぼす
鋼成分の影響を、Ti−48（Ｃ／12＋Ｎ／14）との関係で
調べた結果を図１に示す。また比較のためにNbを含有し
ない以外は前記と同一の条件で製造した鋼についても調
べた。同図から、冷延−焼鈍後のｒ値は、鋼成分に強く
影響し、Ti≧48（Ｃ／12＋Ｎ／14）を満足するTi−Nb複
合添加鋼が、優れたｒ値を示すことがわかる。FIG. 1 shows the results of examining the effect of the steel composition on the r value of the test steel thus obtained in relation to Ti-48 (C / 12 + N / 14). For comparison, steels manufactured under the same conditions as above except that Nb was not included were also examined. The figure shows that the r value after cold rolling and annealing strongly affects the steel composition, and that the Ti-Nb composite added steel satisfying Ti ≧ 48 (C / 12 + N / 14) exhibits an excellent r value. Recognize.
【００１４】[0014]
【作用】上記したようにこの発明では、鋼成分は重要で
あり、前記した成分組成範囲を満足しないと、優れた深
絞り性を確保することができない。以下、各成分につい
て範囲を限定した理由について説明する。As described above, in the present invention, the steel component is important, and unless the above component composition range is satisfied, excellent deep drawability cannot be ensured. Hereinafter, the reason for limiting the range of each component will be described.
【００１５】Ｃ：0.01wt％以下 Ｃは、含有量が少なければ少ない程、深絞り性が向上す
るので、なるべく少なくすることが好ましいが、その含
有量が0.01wt％以下ではさほど悪影響を及ぼさないので
0.01wt％以下に限定した。C: 0.01 wt% or less Since the deep drawability is improved as the content of C is smaller, it is preferable to reduce the content of C as much as possible. However, if the content of C is 0.01 wt% or less, there is no significant adverse effect. Because
It was limited to 0.01 wt% or less.
【００１６】Si：0.5 〜1.5 wt％ Siは、鋼を強化する作用があり、所望の強度に応じて必
要量を含有させるものであるが、その含有量が1.5 wt％
を超えると深絞り性及び表面性状に悪影響を与えるので
1.5 wt％以下に限定した。一方、上述した作用を効果的
に発揮させるために0.5 wt％以上を含有させる。 Mn：3.0 wt％以下、 Mnは、鋼を強化する作用があり、所望の強度に応じて必
要量を含有させるものであるが、その含有量が3.0 wt％
を超えると深絞り性に悪影響を与えるので3.0 wt％以下
に限定した。なお上述した作用を発揮させるためには
0.5wt％程度以上を含有させるのが好ましい。Si: 0.5-1.5 wt% Si has an effect of strengthening steel and contains a necessary amount according to a desired strength. The content is 1.5 wt%.
Exceeding the range will adversely affect deep drawability and surface properties.
It was limited to 1.5 wt% or less. On the other hand, 0.5 wt% or more is contained in order to effectively exert the above-mentioned action. Mn: 3.0 wt% or less, Mn has the effect of strengthening steel and contains a necessary amount according to the desired strength, but the content is 3.0 wt%.
Exceeding the range adversely affects deep drawability, so the content was limited to 3.0 wt% or less. In order to exhibit the above-mentioned effect,
It is preferable to contain about 0.5 wt% or more.
【００１７】Ti：0.01〜0.2 wt％ Tiは、この発明において重要な成分であり、鋼中の固溶
（Ｃ，Ｎ）を炭窒化物として析出固定させて低減し、深
絞り性に有利な｛111 ｝方位の結晶粒を優先的に形成さ
せる効果がある。その含有量が 0.01 wt％に満たないと
効果がなく、一方0.2 wt％を超えて含有させても効果の
向上が見られないばかりか、却って延性の劣化を招くの
で0.01〜0.2 wt％に限定した。Ti: 0.01-0.2 wt% Ti is an important component in the present invention, and reduces the solid solution (C, N) in steel by being precipitated and fixed as carbonitride, which is advantageous for deep drawability. This has the effect of preferentially forming crystal grains of the {111} orientation. If the content is less than 0.01 wt%, there is no effect. On the other hand, if the content exceeds 0.2 wt%, not only the effect is not improved but also the ductility is deteriorated, so it is limited to 0.01 to 0.2 wt%. did.
【００１８】Nb：0.001 〜0.2 wt％ Nbは、この発明において重要な成分であり、鋼中の固溶
Ｃを低減させる効果があるとともに、Ti−Nb複合含有さ
せることによって、仕上圧延前の組織の微細化によるｒ
値向上に有効である。Nbの含有量が0.001 wt％に満たな
いとその効果がなく、一方0.2 wt％を超えて含有させて
も効果の向上が見られないので0.001 〜0.2 wt％に限定
した。Nb: 0.001 to 0.2 wt% Nb is an important component in the present invention, and has an effect of reducing solid solution C in steel and has a structure before finish rolling by containing a Ti—Nb composite. R by miniaturization of
It is effective for value improvement. If the content of Nb is less than 0.001 wt%, the effect is not obtained. On the other hand, if the content exceeds 0.2 wt%, the effect is not improved, so the content is limited to 0.001 to 0.2 wt%.
【００１９】Ｂ：0.0001〜0.0020wt％ Ｂは、耐二次加工ぜい性を改善させるために含有させ
る。その含有量が0.0001wt％に満たないと効果がなく、
一方0.002 wt％を超えるて含有させると深絞り性が劣化
するため0.0001〜0.002 wt％に限定した。 Al：0.01〜0.20wt％ Alは、脱酸を行い、炭窒化物形成成分の歩留まりを向上
させるために必要量を含有させるものであり、その含有
量が0.01wt％に満たないとその効果がなく、一方0.20wt
％を超えて含有させても、より一層の脱酸効果は得られ
ないため、0.01〜0.20wt％に限定した。B: 0.0001 to 0.0020 wt% B is contained to improve the resistance to secondary working brittleness. If the content is less than 0.0001wt%, there is no effect,
On the other hand, if the content exceeds 0.002 wt%, the deep drawability deteriorates, so the content is limited to 0.0001 to 0.002 wt%. Al: 0.01 to 0.20 wt% Al is used to deoxidize and contain the necessary amount to improve the yield of carbonitride-forming components. If the content is less than 0.01 wt%, the effect is reduced. But not 0.20wt
%, A further deoxidizing effect cannot be obtained, so the content was limited to 0.01 to 0.20 wt%.
【００２０】Ｐ：0.03〜0.20wt％ Ｐは、鋼を強化する作用があり、所望の強度に応じて必
要量を含有させるものであるが、その含有量が0.03wt％
に満たないと高強度化の効果がなく、一方0.20wt％を超
えると深絞り性に悪影響を与えるので0.03〜0.20wt％に
限定した。P: 0.03 to 0.20 wt% P has an effect of strengthening steel and contains a necessary amount according to a desired strength. The content is 0.03 wt%.
If less than the above, there is no effect of increasing the strength. On the other hand, if it exceeds 0.20 wt%, the deep drawability is adversely affected, so the content was limited to 0.03 to 0.20 wt%.
【００２１】Ｓ：0.05wt％以下 Ｓは、少なければ少ない程、深絞り性が向上するので、
できるだけ含有量を抑制することが好ましいが、その含
有量が0.05wt％以下ではさほど悪影響を及ぼさないので
0.05 wt％以下に限定した。S: 0.05 wt% or less Since the smaller S is, the deeper drawability is improved,
It is preferable to suppress the content as much as possible, but if the content is 0.05 wt% or less, there is no significant adverse effect.
It was limited to 0.05 wt% or less.
【００２２】Ｎ：0.01wt％以下 Ｎは、少なければ少ない程、深絞り性が向上するので、
できるだけ含有量を抑制することが好ましいが、その含
有量が0.01wt％以下ではさほど悪影響を及ぼさないので
0.01wt％以下に限定した。N: 0.01 wt% or less Since the smaller N is, the deeper drawability is improved,
It is preferable to suppress the content as much as possible, but if the content is 0.01 wt% or less, there is no significant adverse effect.
It was limited to 0.01 wt% or less.
【００２３】この発明では、上記Ｃ，Ti及びＮの各含有
量〔Ｃ〕，〔Ti〕及び〔Ｎ〕が次式In the present invention, the contents of [C], [Ti] and [N] of C, Ti and N are represented by the following formulas:
【数２】 〔Ti〕≧48（〔Ｃ〕／12＋〔Ｎ〕／14）（wt％） …（１） を満足しなければならない。Tiは、前述したとおり炭窒
化物形成成分であり、鋼中の固溶（Ｃ，Ｎ）を低減さ
せ、深絞り性に有利な｛111 ｝方位の結晶粒を優先的に
形成させる作用がある。しかしながら上記(1) 式を満足
しない場合には、図１でも明らかなようにその効果が見
られず、優れた深絞り性が得られないので、[Ti] ≧ 48 ([C] / 12 + [N] / 14) (wt%) (1) Ti is a carbonitride forming component as described above, and has an effect of reducing solid solution (C, N) in steel and preferentially forming crystal grains of {111} orientation which is advantageous for deep drawability. . However, when the above expression (1) is not satisfied, the effect is not seen as apparent from FIG. 1 and excellent deep drawability cannot be obtained.
【数３】 〔Ti〕≧48（〔Ｃ〕／12＋〔Ｎ〕／14）（wt％） に限定した。## EQU00003 ## [Ti] .gtoreq.48 ([C] / 12 + [N] / 14) (wt%).
【００２４】Mo：0.01〜1.0 wt％ Moは、鋼を強化する作用があり、第２発明では所望の強
度に応じて含有させるものであるが、その含有量が0.01
wt％に満たないと効果がなく、一方1.0 wt％を超えると
深絞り性に悪影響を与えるので0.01〜1.0 wt％に限定し
た。Mo: 0.01 to 1.0 wt% Mo has an effect of strengthening steel, and in the second invention, Mo is contained according to a desired strength.
If the amount is less than wt%, there is no effect. On the other hand, if it exceeds 1.0 wt%, the deep drawability is adversely affected, so the amount is limited to 0.01 to 1.0 wt%.
【００２５】Cu：0.1 〜1.5 wt％ Cuは、鋼を強化する作用があり、第３発明では所望の強
度に応じて含有させるものであるが、その含有量が0.1
wt％に満たないと効果がなく、一方1.5 wt％を超えると
深絞り性に悪影響を与えるので0.1 〜1.5 wt％に限定し
た。Cu: 0.1 to 1.5 wt% Cu has an effect of strengthening steel. In the third invention, Cu is contained according to a desired strength.
If the amount is less than wt%, there is no effect. On the other hand, if it exceeds 1.5 wt%, the deep drawability is adversely affected, so the amount is limited to 0.1 to 1.5 wt%.
【００２６】Ni：0.1 〜1.5 wt％ 第３発明ではNiを含有させる。Niは、鋼を強化する作用
があるとともに、Cu含有時の鋼板表面性状の改善効果が
ある。その含有量が0.1 wt％に満たないと効果がなく、
一方1.5 wt％を超えると深絞り性に悪影響を与えるので
0.1 〜1.5 wt％に限定した。Ni: 0.1 to 1.5 wt% In the third invention, Ni is contained. Ni has the effect of strengthening the steel and has the effect of improving the surface properties of the steel sheet when Cu is contained. If the content is less than 0.1 wt%, there is no effect,
On the other hand, if the content exceeds 1.5 wt%, deep drawability is adversely affected.
Limited to 0.1-1.5 wt%.
【００２７】次にこの発明で製造工程について限定した
理由について説明する。 圧延工程 圧延工程は、この発明で最も重要であり、Ar3 変態点以
下500 ℃以上の温度域にて、潤滑を施しつつ合計圧下率
が50％以上95％以下になる圧延工程を施し、次いで巻取
又は焼鈍工程により再結晶処理を施すことが必要であ
る。ここにAr3 変態点より高い温度域では、いくら圧延
をおこなってもγ−α変態により集合組織がランダム化
するため、熱延板に｛111 ｝集合組織が形成されず、そ
のため冷延−焼鈍後には低いｒ値しか得られない。一
方、500 ℃未満に圧延温度を低下させても、より一層の
ｒ値の向上が望めず、圧延荷重が増大するのみであるの
で、圧延温度はAr3 変態点以下500 ℃以上に限定した。Next, the reason why the manufacturing process is limited in the present invention will be described. Rolling Step The rolling step is the most important in the present invention. In the temperature range of 500 ° C. or lower below the Ar 3 transformation point, the rolling step is performed in which the total draft is 50% or more and 95% or less while performing lubrication. It is necessary to perform a recrystallization treatment by a winding or annealing step. Here, in the temperature range higher than the Ar 3 transformation point, no matter how much rolling is performed, the texture is randomized by the γ-α transformation, so that the {111} texture is not formed in the hot-rolled sheet, and therefore, the cold-rolled-annealed Later only low r values are obtained. On the other hand, even if the rolling temperature is lowered to less than 500 ° C., further improvement of the r value cannot be expected and only the rolling load increases, so the rolling temperature was limited to the Ar 3 transformation point or lower and 500 ° C. or higher.
【００２８】この圧延の圧下率は、50％に満たないと熱
延板に｛111 ｝集合組織が形成されず、一方95％を超え
ると熱延板にｒ値に好ましくない集合組織が形成すると
いう不都合を生じるので50％以上95％以下に限定した。If the rolling reduction of this rolling is less than 50%, no {111} texture is formed in the hot-rolled sheet, while if it exceeds 95%, an undesired texture is formed in the hot-rolled sheet with an r value. Therefore, it is limited to 50% or more and 95% or less.
【００２９】さらにAr3 変態点以下の圧延を無潤滑圧延
とすると、ロールと鋼板との間の摩擦力に起因するせん
断変形により、深絞り性に好ましくない｛110 ｝方位の
結晶粒が鋼板表層部に優先的に形成され、ｒ値の向上が
望めないので深絞り性を確保するためには潤滑圧延とす
ることが必要である。Furthermore, if rolling below the Ar 3 transformation point is referred to as lubrication-free rolling, due to shear deformation caused by the frictional force between the roll and the steel sheet, crystal grains having a {110} orientation, which is not preferable for deep drawing, are formed on the surface of the steel sheet. Since it is formed preferentially in the portion and the improvement of the r value cannot be expected, it is necessary to perform lubrication rolling in order to secure the deep drawability.
【００３０】ここに上記圧延におけるロール径、ロール
の構造、潤滑剤の種類並びに圧延機の種類は任意で良
い。なお、上記の圧延前の工程については特に限定をす
るものではなく、例えば圧延素材については、連続鋳造
スラブを再加熱又は連続鋳造後、Ar3 変態点以下に降温
することなく直ちに、又は保温処理したものを粗圧延に
てシートバーにしたものを使用するのが好適である。ま
た上記の圧延を、仕上温度がAr3 以上である熱間圧延に
引き続いて行ってもよい。かかる熱間圧延の粗圧延条件
としては、仕上圧延前の組織の微細化を目的に、粗圧延
終了温度を（Ar3 変態点〜Ar3 変態点＋100 ℃）とする
ことが好ましい。Here, the roll diameter, roll structure, type of lubricant and type of rolling mill in the above-mentioned rolling may be arbitrary. The steps before the above-mentioned rolling are not particularly limited.For example, for a rolled material, after reheating or continuously casting a continuous casting slab, immediately without lowering the temperature below the Ar 3 transformation point, or a heat retaining treatment. It is preferable to use what has been made into a sheet bar by rough rolling. Further, the above-mentioned rolling may be performed subsequent to hot rolling in which the finishing temperature is Ar 3 or more. As the rough rolling conditions for such hot rolling, it is preferable to set the rough rolling end temperature to (Ar 3 transformation point to Ar 3 transformation point + 100 ° C.) for the purpose of refining the structure before finish rolling.
【００３１】次にこの発明の鋼は、熱延温度がAr3 変態
点以下であるため、圧延板は加工組織を呈している。そ
のため、この圧延板には次いで再結晶処理を施して｛11
1 ｝方位の結晶粒を形成させる必要がある。再結晶処理
を施さないと、圧延板に ｛111 ｝方位の結晶粒が形成
しないため、その後の冷延−焼鈍によってもｒ値の向上
は望めない。なお、この再結晶処理は、巻取又は焼鈍工
程により行うことができる。巻取工程による再結晶処理
には、600 ℃以上の巻取温度が好ましく、それよりも低
い巻取温度では再結晶は完了せず、その後の冷延−焼鈍
によってもｒ値の向上は望めない。また熱延後の焼鈍に
より再結晶を行う場合には、熱延時の巻取温度は任意で
よく、600 ℃以上の再結晶焼鈍が好ましい。Next, since the steel of the present invention has a hot rolling temperature of not more than the Ar 3 transformation point, the rolled sheet has a worked structure. Therefore, the rolled sheet is then subjected to a recrystallization treatment,
It is necessary to form crystal grains of 1｝ orientation. Unless the recrystallization treatment is performed, no {111} crystal grains are formed in the rolled sheet, so that an increase in the r value cannot be expected even by subsequent cold rolling and annealing. This recrystallization treatment can be performed by a winding or annealing step. For the recrystallization treatment in the winding step, a winding temperature of 600 ° C. or more is preferable. At a lower winding temperature, recrystallization is not completed, and no improvement in the r value can be expected even by subsequent cold rolling and annealing. . When recrystallization is performed by annealing after hot rolling, the winding temperature during hot rolling may be arbitrary, and recrystallization annealing at 600 ° C. or more is preferred.
【００３２】冷間圧延工程 この工程は、高いｒ値を得るために必須であり、冷延圧
下率は50〜95％とすることが不可欠である。かかる冷延
圧下率が50％未満又は95％を超えると、優れた深絞り性
が得られない。Cold Rolling Step This step is indispensable for obtaining a high r value, and it is essential that the cold rolling reduction is 50 to 95%. If the cold rolling reduction is less than 50% or more than 95%, excellent deep drawability cannot be obtained.
【００３３】焼鈍工程 冷間圧延を経た冷延鋼帯は、再結晶焼鈍を施す必要があ
る。この再結晶焼鈍は、箱型焼鈍法及び連続型焼鈍法の
いずれでもよい。焼鈍温度は650 〜980 ℃の範囲が好ま
しい。なお焼鈍後の鋼帯に、表面粗度等の調整のため
に、通常行われる10％以下の調質圧延を施しても良いこ
とは言うまでもない。またこの発明にて得られた冷延鋼
板は、加工用表面処理鋼板の原板にも適用できる。表面
処理としては、亜鉛めっき（合金系を含む）、すずめっ
き、ほうろう等がある。Annealing Step The cold-rolled steel strip that has been subjected to cold rolling must be subjected to recrystallization annealing. This recrystallization annealing may be either a box-type annealing method or a continuous-type annealing method. The annealing temperature is preferably in the range of 650 to 980 ° C. Needless to say, the steel strip after annealing may be subjected to a temper rolling of 10% or less, which is usually performed, in order to adjust the surface roughness and the like. Further, the cold-rolled steel sheet obtained by the present invention can be applied to an original sheet of a surface-treated steel sheet for processing. Examples of the surface treatment include zinc plating (including alloys), tin plating, and enamel.
【００３４】[0034]
【実施例】表１に示す種々の成分組成になる鋼スラブを
準備した。EXAMPLES Steel slabs having various component compositions shown in Table 1 were prepared.
【００３５】[0035]
【表１】 [Table 1]
【００３６】これらのスラブを表２に示す熱延条件で粗
圧延、仕上圧延及び再結晶処理を行った。なお表１及び
表２において、数値がこの発明の範囲を外れるものには
下線をひいてある。These slabs were subjected to rough rolling, finish rolling and recrystallization under the hot rolling conditions shown in Table 2. In Tables 1 and 2, the values out of the range of the present invention are underlined.
【００３７】[0037]
【表２】 [Table 2]
【００３８】得られた熱延板を酸洗後、表２に示した条
件にて冷間圧延を施し板厚0.7 mmの冷延鋼板にした後、
連続焼鈍設備にて表２に示した条件にて再結晶焼鈍を施
した。かくして得られた冷延鋼板の材料特性について調
べた結果を表２に併記した。なお引張特性は、JIS 5 号
引張試験片を用いて測定した。またｒ値は、15％引張予
ひずみを与えたのち、３点法にて測定し、Ｌ方向（圧延
方向）、Ｄ方向（圧延方向から45度方向）及びＣ方向
（圧延方向から90度方向）の平均値を ｒ＝（ｒL ＋２ｒD ＋ｒC ）／４ の式から求めた。さらに耐二次加工ぜい性の評価として
は、限界絞り比2.8 にて加工したサンプルを−50℃に冷
却したのち、圧潰試験を行い、ぜい性割れ発生の有無に
て評価した。After pickling the obtained hot-rolled sheet, it was cold-rolled under the conditions shown in Table 2 to obtain a cold-rolled steel sheet having a thickness of 0.7 mm.
Recrystallization annealing was performed in the continuous annealing equipment under the conditions shown in Table 2. The results of examining the material properties of the cold rolled steel sheet thus obtained are also shown in Table 2. The tensile properties were measured using a JIS No. 5 tensile test piece. The r value is measured by a three-point method after 15% tensile prestrain is applied, and the L direction (rolling direction), the D direction (45 degrees from the rolling direction) and the C direction (90 degrees from the rolling direction) ) Was determined from the equation: r = (r L + 2r D + r C ) / 4. Further, as to the evaluation of the secondary working brittle resistance, a sample processed at a limit drawing ratio of 2.8 was cooled to -50 ° C, and then a crush test was performed to evaluate whether brittle cracks were generated.
【００３９】表２から明らかなように、この発明に従う
適合例は、いずれも比較例に比べて優れた深絞り性を有
している。As is clear from Table 2, each of the conforming examples according to the present invention has an excellent deep drawability as compared with the comparative example.
【００４０】[0040]
【発明の効果】この発明によれば、鋼成分及び製造条件
を限定することにより、深絞り性に優れた高強度冷延鋼
板を製造することが可能になる。According to the present invention, it is possible to manufacture a high-strength cold-rolled steel sheet having excellent deep drawability by limiting the steel composition and the manufacturing conditions.
【図１】図１は、ｒ値に及ぼすｒ値に及ぼす鋼成分の影
響を、Ti−48（Ｃ／12＋Ｎ／14）との関係で示すグラフ
である。FIG. 1 is a graph showing the effect of a steel component on an r value on an r value in relation to Ti-48 (C / 12 + N / 14).
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.7 識別記号 ＦＩ Ｃ２２Ｃ 38/14 Ｃ２２Ｃ 38/14 38/16 38/16 Ｃ２３Ｃ 2/02 Ｃ２３Ｃ 2/02 (56)参考文献 特開 平３−150316（ＪＰ，Ａ) 特開 平２−47222（ＪＰ，Ａ) 特開 平５−339641（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) C21D 8/00 - 9/48 C22C 38/00 - 38/58 C23C 2/02 ──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. 7 Identification code FI C22C 38/14 C22C 38/14 38/16 38/16 C23C 2/02 C23C 2/02 (56) References JP-A-3-3 150316 (JP, A) JP-A-2-47222 (JP, A) JP-A-5-339641 (JP, A) (58) Fields investigated (Int. Cl. 7 , DB name) C21D 8 / 00-9 / 48 C22C 38/00-38/58 C23C 2/02
Claims (4)
i〕及び〔Ｎ〕が次式 〔Ti〕≧48（〔Ｃ〕／12＋〔Ｎ〕／14） （wt％） を満足する基本成分組成になり、残部はFe及び不可避的
不純物よりなる鋼素材を、Ar3 変態点以下500 ℃以上の
温度域にて潤滑を施しつつ、合計圧下率が50％以上95％
以下になる圧延加工を施し、次いで巻取又は焼鈍工程に
より再結晶処理を施した後、圧下率50〜95％の冷間圧延
を施し、 引き続き再結晶焼鈍を施すことを特徴とする、深絞り性
に優れた高強度冷延鋼板の製造方法。1. C: 0.01 wt% or less, Si: 0.5 to 1.5 wt%, Mn: 3.0 wt% or less, Ti: 0.01 to 0.2 wt%, Nb: 0.001 to 0.2 wt%, B: 0.0001 to 0.0020 wt% , Al: 0.01 to 0.20 wt%, P: 0.03 to 0.20 wt%, S: 0.05 wt% or less, and N: 0.01 wt% or less, and the respective contents of C, Ti and N [C], [T
i] and [N] are basic steel compositions satisfying the following formula: [Ti] ≧ 48 ([C] / 12 + [N] / 14) (wt%), the balance being Fe and unavoidable impurities. With a total draft of 50% or more and 95% or more while lubricating in a temperature range of 500 ° C or less below the Ar 3 transformation point.
Deep drawing, characterized by rolling the steel sheet into the following form, then performing a recrystallization treatment in a winding or annealing step, then performing cold rolling at a reduction rate of 50 to 95%, and subsequently performing recrystallization annealing. Of high strength cold rolled steel sheet with excellent heat resistance.
鋼板の製造方法。2. The method for producing a high-strength cold-rolled steel sheet having excellent deep drawability according to claim 1, which further comprises Mo: 0.01 to 1.0 wt% in addition to the basic component composition.
度冷延鋼板の製造方法。3. The method for producing a high-strength cold-rolled steel sheet excellent in deep drawability according to claim 1 or 2, further comprising: 0.1 to 1.5 wt% of Cu and 0.1 to 1.5 wt% of Ni in addition to the basic component composition. .
後の再結晶焼鈍が連続溶融亜鉛めっきラインで行うもの
である深絞り性に優れた高強度亜鉛めっき鋼板の製造方
法。4. The method for producing a high-strength galvanized steel sheet according to claim 1, 2 or 3, wherein recrystallization annealing after cold rolling is performed in a continuous hot-dip galvanizing line.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4038008A JP3043883B2 (en) | 1992-02-25 | 1992-02-25 | Method for producing high-strength cold-rolled steel sheet and galvanized steel sheet with excellent deep drawability |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4038008A JP3043883B2 (en) | 1992-02-25 | 1992-02-25 | Method for producing high-strength cold-rolled steel sheet and galvanized steel sheet with excellent deep drawability |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH05230541A JPH05230541A (en) | 1993-09-07 |
| JP3043883B2 true JP3043883B2 (en) | 2000-05-22 |
Family
ID=12513551
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4038008A Expired - Fee Related JP3043883B2 (en) | 1992-02-25 | 1992-02-25 | Method for producing high-strength cold-rolled steel sheet and galvanized steel sheet with excellent deep drawability |
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| Country | Link |
|---|---|
| JP (1) | JP3043883B2 (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1518001A4 (en) | 2002-06-28 | 2006-01-11 | Posco | Super formable high strength steel sheet and method of manufacturing thereof |
-
1992
- 1992-02-25 JP JP4038008A patent/JP3043883B2/en not_active Expired - Fee Related
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| Publication number | Publication date |
|---|---|
| JPH05230541A (en) | 1993-09-07 |
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