JPH0452229A - Highly efficient production of cold rolled steel sheet extremely excellent in workability - Google Patents
Highly efficient production of cold rolled steel sheet extremely excellent in workabilityInfo
- Publication number
- JPH0452229A JPH0452229A JP15858690A JP15858690A JPH0452229A JP H0452229 A JPH0452229 A JP H0452229A JP 15858690 A JP15858690 A JP 15858690A JP 15858690 A JP15858690 A JP 15858690A JP H0452229 A JPH0452229 A JP H0452229A
- Authority
- JP
- Japan
- Prior art keywords
- rolling
- cold
- rolled
- temperature
- hot
- 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.)
- Granted
Links
- 239000010960 cold rolled steel Substances 0.000 title claims abstract description 11
- 238000004519 manufacturing process Methods 0.000 title claims description 6
- 238000005096 rolling process Methods 0.000 claims abstract description 33
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 28
- 239000010959 steel Substances 0.000 claims abstract description 28
- 238000000137 annealing Methods 0.000 claims abstract description 21
- 238000001816 cooling Methods 0.000 claims abstract description 18
- 238000005097 cold rolling Methods 0.000 claims abstract description 14
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 12
- 239000012535 impurity Substances 0.000 claims abstract description 7
- 229910052757 nitrogen Inorganic materials 0.000 claims abstract description 7
- 230000009467 reduction Effects 0.000 claims description 15
- 238000005098 hot rolling Methods 0.000 abstract description 16
- 238000010438 heat treatment Methods 0.000 abstract description 6
- 239000000203 mixture Substances 0.000 abstract description 4
- 239000002253 acid Substances 0.000 abstract description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 abstract 2
- 239000010962 carbon steel Substances 0.000 abstract 1
- 229910052742 iron Inorganic materials 0.000 abstract 1
- 230000001105 regulatory effect Effects 0.000 abstract 1
- 229910021384 soft carbon Inorganic materials 0.000 abstract 1
- 230000000694 effects Effects 0.000 description 19
- 239000000463 material Substances 0.000 description 10
- 238000004804 winding Methods 0.000 description 9
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 8
- 239000006104 solid solution Substances 0.000 description 8
- 239000002244 precipitate Substances 0.000 description 6
- 238000001556 precipitation Methods 0.000 description 6
- 239000013078 crystal Substances 0.000 description 5
- 230000002411 adverse Effects 0.000 description 3
- 238000007747 plating Methods 0.000 description 3
- 238000009849 vacuum degassing Methods 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 229910001335 Galvanized steel Inorganic materials 0.000 description 2
- 229910001209 Low-carbon steel Inorganic materials 0.000 description 2
- 230000033228 biological regulation Effects 0.000 description 2
- 238000009749 continuous casting Methods 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- 239000008397 galvanized steel Substances 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 230000009466 transformation Effects 0.000 description 2
- 230000007704 transition Effects 0.000 description 2
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 1
- 238000005275 alloying Methods 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 230000008094 contradictory effect Effects 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 230000002542 deteriorative effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000005246 galvanizing Methods 0.000 description 1
- 239000004615 ingredient Substances 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 238000003672 processing method Methods 0.000 description 1
- 238000001953 recrystallisation Methods 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 238000002791 soaking Methods 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
- 238000005482 strain hardening Methods 0.000 description 1
- 238000005728 strengthening Methods 0.000 description 1
- 238000009864 tensile test Methods 0.000 description 1
- 239000002023 wood Substances 0.000 description 1
Abstract
Description
【発明の詳細な説明】
（産業上の利用分野）
本発明は、自動車外板などで特に超深絞り性が必要とさ
れる用途に適した極めて優れた深絞り加工性を有する極
低炭素冷延鋼板を効率的に製造する方法に係わる。Detailed Description of the Invention (Industrial Field of Application) The present invention is an ultra-low carbon cooling material with extremely excellent deep drawability, which is suitable for applications where ultra-deep drawability is particularly required, such as in automobile outer panels. It concerns a method for efficiently manufacturing rolled steel plates.
（従来の技術）
冷延鋼板の規定であるＪＩＳ Ｇ ３１４１ＳＰ ＣＥ
級を超える超深絞り用冷延鋼板として、極低炭素ＴＩ添
加冷延鋼板が発明され（特公昭４４−１ｓ０８６号公報
）、冷延鋼板の用途が飛躍的に広がった。それとともに
この鋼の改善・改良がその後大いに進められた。現在で
は、ＴＩ、Ｎｂの複合添加による加工性特に深絞り性の
一層の向上やＢ添加による耐二次加工性向上等が図られ
ている。これらに対する先行技術としては、例えば特開
昭５９−１４０３３３号、特開昭８１−１１３７２４号
、特開昭６１−１１３７２５号公報等がある。(Prior art) JIS G 3141SP CE, which is the regulation for cold rolled steel sheets
As a cold-rolled steel sheet for ultra-deep drawing that exceeds the grade, an ultra-low carbon TI-added cold-rolled steel sheet was invented (Japanese Patent Publication No. 44-1s086), and the uses of cold-rolled steel sheets have expanded dramatically. At the same time, improvements and improvements to this steel have since progressed greatly. At present, efforts are being made to further improve workability, particularly deep drawability, by adding a combination of TI and Nb, and to improve secondary workability by adding B. As prior art for these, there are, for example, JP-A-59-140333, JP-A-81-113724, and JP-A-61-113725.
（発明が解決しようとする課題）
この極低炭素ＴＩ添加鋼の冷延・焼鈍後の特性は、高純
化を主とした成分とともに熱延条件の影響が極めて大き
く、そのためその変動による材質のバラツキが生じ、そ
れが歩留まり落ちとなり経済性を損なうという、自動車
用鋼板のような大量消費材にとっては、致命的な欠点が
あった。これはそもそも製鋼で真空脱ガス等が必要で費
用を要する該鋼にあっては極めて大きな問題点であった
。(Problem to be solved by the invention) The properties of this ultra-low carbon TI-added steel after cold rolling and annealing are extremely influenced by the hot rolling conditions as well as the components that mainly improve the purity. This is a fatal drawback for mass-consumable products such as steel sheets for automobiles, which causes a decrease in yield and impairs economic efficiency. This is an extremely serious problem in steel production, which requires vacuum degassing and is expensive.
これら極低炭素冷延鋼板はそもそもかなり加工性に優れ
たものであるが、本発明ではそのうちのランクフォード
値（以下？値という）で示される深絞り性がより一層向
上した超深絞り性を付与させるとともに、つぎに示す工
業上の安定性を増す製造方法を提供するものである。These ultra-low carbon cold-rolled steel sheets have excellent workability to begin with, but in the present invention, we have developed ultra-deep drawability that has further improved deep drawability as indicated by the Lankford value (hereinafter referred to as ? value). The purpose of the present invention is to provide a manufacturing method that increases industrial stability as described below.
（課題を解決するための手段）
本発明はこのような課題に対して、特定成分の高純度鋼
を特定の熱延、特に仕上圧延条件〜巻取までを従来にな
い条件をとることで解決しようとするもので、その骨子
とするところは、ＩａＳＳ％で、Ｃ二０．００４０％以
下、Ｎ ： ０．００４０％以下、Ｍ口：０．０５〜０
．４％、Ｓ ：０．０１５％以下、酸可溶Ａ、９（以下
ｓｏ１．ＡＩ ）：０．００５〜０．１００％、Ｔｆ：
０．０４〜０．０８５％、Ｂ ： ０．０００１〜０．
００１０％を含有し、残部不可避的不純物元素からなる
鋼を、１２００℃以下に加熱後熱延するにあたり、粗仕
上厚みを４５＋＋ｍ以上とし、次式で示される有効ひず
みをεｅｆｆを４５％以上とり、８８０℃以上の温度で
仕上圧延を終了した後、１ｓ以内に冷却を開始し２０℃
／Ｓ以上の平均冷却速度で８３０℃以下まで冷却を行い
、続いて６８０〜８００℃の温度で巻取り、引続き７５
〜９０％の冷延率で冷延を行い、７８０〜８７０℃の温
度で連続焼鈍を行うことを特徴とする加工性の極めて優
れた冷延鋼板の高効率な製造方法である。(Means for Solving the Problems) The present invention solves these problems by hot-rolling high-purity steel with a specific composition, and in particular, by applying unprecedented conditions from finish rolling to winding. The main points are IaSS%, C2: 0.0040% or less, N: 0.0040% or less, M: 0.05 to 0.
．． 4%, S: 0.015% or less, acid soluble A, 9 (hereinafter so1.AI): 0.005-0.100%, Tf:
0.04-0.085%, B: 0.0001-0.
When hot-rolling a steel containing 0.0010% and the remainder consisting of unavoidable impurity elements after heating to 1200 ° C. or less, the rough finishing thickness is set to 45++ m or more, and the effective strain expressed by the following formula is set to εeff of 45% or more, After finish rolling at a temperature of 880°C or higher, cooling is started within 1 s and the temperature is 20°C.
Cooling is performed to 830°C or less at an average cooling rate of /S or more, followed by winding at a temperature of 680 to 800°C, and then 75°C.
This is a highly efficient manufacturing method for cold-rolled steel sheets with extremely excellent workability, characterized by cold rolling at a cold rolling rate of ~90% and continuous annealing at a temperature of 780-870°C.
ユニに、
ε８「「−最終パス圧下率（％）＋１７２最終１段前パ
ス圧下率（％）＋１ハ最終２段前パス圧下率（％）
とする。For Uni, ε8 "- Final pass rolling reduction rate (%) + 172 Pass rolling reduction rate (%) before the final 1st stage + 1 C Pass rolling reduction rate (%) before the final 2nd stage.
すなわち、成分的には通常使用されるＮｂは使用せずＴ
Ｉを炭素および窒素の化学量論的等量よりかなり多めに
添加する。これは固溶Ｔ１をある量確保しようとするも
のである。さらに、熱延にあたり、比較的低温で加熱し
た後粗仕上厚を厚くすることで、全仕上圧下率を大きく
し、仕上後段の最終に近いほど圧延の効果が発揮される
ような特定の後段圧下をとる熱延を行った後、その効果
をなるべく凍結すべく速やかに冷却を開始し、かつ高温
で巻取る。That is, in terms of components, Nb, which is normally used, is not used and T
I is added in significantly more than the stoichiometric equivalents of carbon and nitrogen. This is intended to ensure a certain amount of solid solution T1. Furthermore, in hot rolling, by increasing the rough finishing thickness after heating at a relatively low temperature, the total finishing reduction ratio can be increased, and a specific later stage rolling where the effect of rolling is exerted closer to the end of the latter stage of finishing can be achieved. After hot rolling for a certain amount of time, cooling is immediately started to freeze the effect as much as possible, and winding is performed at a high temperature.
この効果の機構はいまだ定かではないが、このような高
純度鋼の前処理として熱延板に期待される要件は、細粒
でかつ不純物の極度に少ないマトリックスの提供にある
と考えられる。Although the mechanism of this effect is still unclear, it is thought that the requirements expected of hot-rolled sheets as a pretreatment for such high-purity steels are the provision of a fine-grained matrix with extremely low impurities.
この両者はそもそも相反するもので、また、その制御は
極めて微妙である。しかしながら、全仕上圧下率を大き
くすることで、析出物のひずみ銹起析出が促進されγ中
での析出処理は完全となる。These two are contradictory to begin with, and their control is extremely delicate. However, by increasing the total finishing reduction rate, the strain-induced precipitation of precipitates is promoted and the precipitation treatment in γ is completed.
そして仕上終段域を高圧下とすることで、安定して微細
な再結晶γ粒が得られる。By placing the final finishing stage under high pressure, fine recrystallized γ grains can be stably obtained.
そして、γ粒の成長、γ／α変態、α粒の成長を通じて
形成される熱延板結晶粒を、圧延後部急冷することによ
り、圧延ままの状態で凍結する。Then, the hot-rolled sheet crystal grains formed through the growth of γ grains, γ/α transformation, and growth of α grains are frozen in the as-rolled state by rapidly cooling after rolling.
最後にもはやα粒の成長がほとんどなくなる温度域で巻
取り、α中の溶解度の低いことを利用した析出物の析出
・粗大化の徹底をはかる。Finally, coiling is carried out in a temperature range where almost no growth of α grains occurs, and thorough precipitation and coarsening of precipitates is carried out by taking advantage of the low solubility in α.
析出物の粗大化はこのようにγ中およびα中の両方で行
い、熱延細粒化を仕上終段圧下を高め飽和する領域で行
うことで、熱延板での状態を安定して好ましい状態にす
る。In this way, the coarsening of the precipitates is carried out both during γ and α, and the hot-rolling refinement is carried out in the region where the finishing stage final reduction is increased and saturated, thereby stabilizing the condition of the hot-rolled sheet. state.
（作 用）
つぎに各要件の作用および数値限定理由について述べる
。(Effects) Next, we will discuss the effects of each requirement and the reasons for numerical limitations.
Ｃ，Ｎ：Ｃ，Ｎは侵入型固溶元素で集合組織形成に有害
とされる。したがって通常の極低炭素鋼よりもさらに極
力低下させる必要がある。そのため各々０．００４０％
以下とする。好ましくはｃ ： ｏ、ｏ。C, N: C and N are interstitial solid solution elements that are considered harmful to texture formation. Therefore, it is necessary to reduce the carbon content as much as possible compared to ordinary ultra-low carbon steel. Therefore, each is 0.0040%
The following shall apply. Preferably c: o, o.
２５％、Ｎ ： ０．００２０％である。25%, N: 0.0020%.
Ｍｎ：ｆｌ換型固溶体元素であり、多すぎると鋼を硬化
して延性を害する。しかし、鋼中のＳとＭｎＳを形成し
Ｓによる熱間脆性を避ける役割もあり、そのため０．０
５〜０．４％とする。低Ｍｎとしたほうが延性、ｊ値と
もに向上させるので０．１５％以下とすることが好まし
い。Mn: is a fl conversion type solid solution element, and if it is present too much, it hardens the steel and impairs its ductility. However, it also has the role of forming S and MnS in the steel and preventing hot embrittlement due to S, so 0.0
5 to 0.4%. Since lower Mn improves both ductility and j value, it is preferably 0.15% or less.
Ｓ：ＭｎＳとなり、有害介在物となるため極力低減した
方がよい。そのため０．０１５％以下とした。S: Becomes MnS and becomes a harmful inclusion, so it is better to reduce it as much as possible. Therefore, the content was set at 0.015% or less.
好ましくは、Ｍｎを０．１５％以下、Ｓを０．００８％
以下とすることである。Preferably, Mn is 0.15% or less and S is 0.008%.
The following shall be done.
５ｏｌＺ、ＡＩ ＋ ＡＩは脱酸に必要でそのため鋼中
に０．００５〜０．１０％残存する。下限値未満では十
分な脱酸ができず、また上限値超では介在物が増加し鋼
の延性を害する。5olZ, AI + AI is necessary for deoxidation and therefore remains in the steel in an amount of 0.005 to 0.10%. If it is less than the lower limit, sufficient deoxidation cannot be achieved, and if it exceeds the upper limit, inclusions increase and impair the ductility of the steel.
Ｔｊ： Ｔｉは０，０４〜０．０８５％必要である。ま
ずＴｉはＮをＴｉＮの形に固定し固溶Ｎの悪影響をさけ
る。また、大部分のＣもＴｉＣの形で固定する。さらに
固溶Ｔｉは熱延板の再結晶に影響し、これを細粒化する
作用を有しそのため本発明では、この固溶Ｔｉを確保す
るために多量にＴｉを添加する。０．０４％未満の添加
ではこれらの効果がない。Tj: Ti is required in an amount of 0.04 to 0.085%. First, Ti fixes N in the form of TiN and avoids the adverse effects of solid solution N. Furthermore, most of the C is also fixed in the form of TiC. Furthermore, solid solution Ti affects the recrystallization of the hot rolled sheet and has the effect of making the grains finer. Therefore, in the present invention, a large amount of Ti is added in order to ensure this solid solution Ti. Addition of less than 0.04% does not have these effects.
しかし、０．０８５％を超える添加では上記作用以上に
不純物の悪影響が出る。そのため加工性が劣化する。However, if the amount exceeds 0.085%, the adverse effects of impurities will be greater than the above-mentioned effects. As a result, workability deteriorates.
ＢＩＢは二次加工性向上のため添加する。木調のような
高純極低炭素鋼にあっては粒界強化元素である固溶炭素
がなくそのため粒界強度が低い。BIB is added to improve secondary processability. High-purity ultra-low carbon steel such as wood-like steel does not have solid solution carbon, which is a grain boundary strengthening element, and therefore has low grain boundary strength.
これは本発明鋼主加工形式である超深絞り加工を受けた
後、口広げのような二次加工を行った場合に縦割れの形
態で発生する。Ｂはこの二次加工脆性を防止するために
添加する。１ｐｐ−未満ではその効果がなく、１Ｏｐｐ
ｓ＋を超える添加では固溶Ｂによる悪影響が出て、Ｆ値
を劣化させる。This occurs in the form of vertical cracking when secondary processing such as mouth widening is performed after ultra-deep drawing, which is the main processing method for the steel of the present invention. B is added to prevent this secondary processing brittleness. Less than 1pp- has no effect, and 1Opp
If the addition exceeds s+, the solid solution B will have an adverse effect, deteriorating the F value.
熱延加熱温度： １２００℃以下とする。この温度以上
で加熱すると圧延前γ粒が大きくなりすぎ、本誌にした
がった熱延後でも熱延板粒が混粒となり、所定の組織な
らず、さらにまた種々の析出をむやみに溶解させること
で、後の熱延工程での析出・粗大化処理を困難なものに
する。この意味からは、熱延加熱温度は１１００℃以下
とすることが好ましい。Hot rolling heating temperature: 1200°C or less. If heated above this temperature, the pre-rolling γ grains will become too large, and even after hot rolling according to this publication, the hot rolled sheet grains will become mixed grains, the desired structure will not be achieved, and various precipitates will be dissolved unnecessarily. , which makes precipitation and coarsening treatment difficult in the subsequent hot rolling process. From this point of view, the hot rolling heating temperature is preferably 1100°C or less.
粗仕上厚：４５ｍｍ以上の厚みとする。これにより仕上
圧延という比較的低い温度域での圧延率を高め、種々の
析出物のひずみ誘起変態を促進させ粗大化させる。通常
の４０ｍ＋＋■程度ではこの効果は完全ではなく、ひい
ては材質劣化やバラツキをもたらす。好ましくは５５１
１１１以上とすべきである。Rough finish thickness: 45 mm or more. This increases the rolling rate in the relatively low temperature range of finish rolling, promotes strain-induced transformation of various precipitates, and coarsens them. This effect is not perfect at the normal distance of about 40 m++■, which may lead to material deterioration and variations. Preferably 551
It should be 111 or more.
εｅｆｆ ’木調では、上記の効果のため、その粒界お
よび粒内は不純物の少ない、清浄化されたものである。εeff' Due to the above-mentioned effects, the grain boundaries and interior of the grains are clean and have few impurities.
したがって通常の圧延では細粒の結晶粒が得られない。Therefore, fine grains cannot be obtained by normal rolling.
これを克服するのが特定の仕上圧延条件で、特に仕上後
段の３パスの圧延率は非常であることを知見し、この後
段圧下率の効果を工業的に示す指標として種々検討した
結果、次式で示されるε８「「を導出するに至った。す
なわち、εｅｆ’ｆ’−最終パス圧下率（％）＋１／２
最終１段前パス圧下率（Ｘ） ＋ １／４最終２段前パ
ス圧下率（％）
である。We found that specific finishing rolling conditions can overcome this problem, and in particular the rolling rate in the 3 passes in the latter stage of finishing is extremely high.As a result of various studies as an industrial indicator of the effect of the rolling reduction in the latter stage, we found the following: We have derived ε8" shown by the formula. That is, εef'f' - Final pass rolling reduction rate (%) + 1/2
The following formula is given: Pass rolling reduction ratio before the final stage (X) + 1/4 Pass rolling reduction ratio before the final stage two stages (%).
第１図は仕上圧延終了温度とε８２．の関係において、
冷延・焼鈍後の１値をプロットした図である。Figure 1 shows finish rolling finish temperature and ε82. In the relationship,
FIG. 3 is a diagram plotting one value after cold rolling and annealing.
成分は、Ｃ：１５〜２３ｐｐｍ 、Ｎ ： １２〜２０
ｐｐｍ 。Ingredients are C: 15-23 ppm, N: 12-20
ppm.
Ｍ ｎ ＋ ０ 、０８〜０ 、１４％、Ｓ ： ０．
００３〜０．００７％、５ｏｉ１． Ａ ｌ ：０．
０２〜０．０３５％、Ｔ ｉ ： ０．０４３〜０．０
８３％、Ｂ：０．０００３〜０．０００６％で、熱延加
熱温度： １１００〜１１３０℃、粗仕上厚：５５〜θ
０朋、仕上終了後０．３〜０．４Ｓ後に平均３０〜４０
℃／Ｓで約８００〜７８０℃まで急冷し７３０〜７６０
℃で巻取った。続いて８０％冷延後８５０℃で連続焼鈍
を行い、０，３％の調圧を施して試験に供した。Mn+0, 08-0, 14%, S: 0.
003-0.007%, 5oi1. Al: 0.
02-0.035%, Ti: 0.043-0.0
83%, B: 0.0003-0.0006%, hot rolling heating temperature: 1100-1130°C, rough finishing thickness: 55-θ
0, average 30-40 0.3-0.4S after finishing
Rapid cooling at ℃/S to about 800-780℃ and 730-760℃
It was rolled up at ℃. Subsequently, after 80% cold rolling, continuous annealing was performed at 850° C., pressure was adjusted to 0.3%, and the test was performed.
図から明らかなようにεｅｆＴが４５％以上で仕上圧延
終了温度の広い範囲で安定してｊ値が２．２以上程度の
極めて高い値を示す。より安定して高１値を示すにはε
ｅｆｒは６０％以上が好ましい。As is clear from the figure, when εefT is 45% or more, the j value is stable over a wide range of finish rolling completion temperatures and exhibits an extremely high value of about 2.2 or more. To show a high 1 value more stably, ε
Efr is preferably 60% or more.
仕上圧延終了温度＝９５０〜８８０℃とする。これを超
える温度では第１図かられかるように、いかにε８４．
を高めようと安定して高加工特性が得られない。また、
８８０℃を下回る温度では一部α域圧延となる場合があ
り、材質が出ないばかりでなく、肌荒れ等の欠陥も発生
する。Finish rolling end temperature is set at 950 to 880°C. As can be seen from Figure 1, at temperatures exceeding this, ε84.
Even if you try to increase the processability, you cannot stably obtain high processing characteristics. Also,
At temperatures below 880°C, some rolling may occur in the α region, which not only results in poor material quality but also causes defects such as rough skin.
圧延後の冷却条件：上述のようにして得られた熱延の組
織を、特に結晶粒度を粗大化させないため、１５以内に
冷却を開始し、平均２０℃／Ｓ以上で８３０℃以下まで
冷却する。この条件をはずすと結晶が粗大化し、一定の
材質が得られない。この場合特に冷却開始までの時間が
重要で１ｓ以内、好ましくは０．５ｓ以内とすべきであ
る。冷却速度が２０℃／Ｓ未満では冷却中に粒の粗大化
が生じる。Cooling conditions after rolling: In order not to coarsen the grain size of the hot-rolled structure obtained as described above, cooling is started within 15 minutes and cooled to 830°C or less at an average rate of 20°C/S or more. . If this condition is not met, the crystals will become coarse and a certain quality of material cannot be obtained. In this case, the time required to start cooling is particularly important and should be within 1 s, preferably within 0.5 s. If the cooling rate is less than 20° C./S, grains will become coarser during cooling.
８３０℃以下ではもはや結晶粒成長は起こりにくいので
この冷却の終点は８３０℃とする。Since crystal grain growth is no longer likely to occur below 830°C, the end point of this cooling is set at 830°C.
巻取温度：巻取後の保温効果で析出の促進および析出物
の粗大化を図る。６８０℃未満ではこの効果が少なく、
８００℃を超えると圧延組織の凍結が十分でなく結晶粒
の粗大化が起こる可能性があるので、巻取温度は６８０
〜８００℃とした。析出粗大化を十分に行うには巻取温
度は７２０℃以上とすることが好ましい。Winding temperature: The heat retention effect after winding promotes precipitation and coarsens the precipitates. Below 680℃, this effect is small;
If the temperature exceeds 800°C, the rolled structure may not freeze sufficiently and the crystal grains may become coarse, so the coiling temperature should be set at 680°C.
The temperature was 800°C. In order to sufficiently coarsen the precipitation, the winding temperature is preferably 720° C. or higher.
冷延率：冷延率は高？値とするため７５％以上必要であ
る。好ましくは７８％以上である。一方、本鋼において
は圧下率は９３％程度まで増してもＦは向上するところ
であるが、工業的に困難な領域であるので上限を９０％
とした。Cold rolling rate: Is the cold rolling rate high? 75% or more is required to obtain the desired value. Preferably it is 78% or more. On the other hand, in this steel, even if the reduction rate is increased to about 93%, the F value will improve, but since this is an industrially difficult area, the upper limit should be set at 90%.
And so.
焼鈍温度二連続焼鈍の焼鈍温度は十分軟質で高ｆ値集合
組織とするため７８０℃は必要である。Annealing temperature The annealing temperature for two successive annealing is required to be 780° C. in order to obtain a sufficiently soft texture with a high f-value.
方、上限は８７０℃とする。これを超える高温での焼鈍
では、本鋼のように粒成長しやすい鋼では、製品として
の結晶粒が大きくなり過ぎてプレス成形後に肌荒れを生
じる。焼鈍温度としては、連続焼鈍では比較的高い８３
０℃以上の高温焼鈍が好ましい。On the other hand, the upper limit is 870°C. When annealing at a higher temperature than this, in a steel that tends to grow grains like this steel, the crystal grains in the product become too large, resulting in rough skin after press forming. The annealing temperature is relatively high for continuous annealing.83
High temperature annealing of 0° C. or higher is preferred.
以上本発明の構成要件の作用について述べたが、本発明
の鋼の溶製は通常転炉で行いＲＨ等の真空脱ガスにて極
低炭素とする。そして通常連続鋳造にて鋼片とされる。Although the effects of the constituent elements of the present invention have been described above, the steel of the present invention is usually melted in a converter and is made to have extremely low carbon by vacuum degassing such as RH. Then, it is usually made into steel billets by continuous casting.
熱延は圧延５台以上のタンデム圧延機で仕上圧延される
。全仕上圧下率を本発明にしたがって高め、かつ仕上終
了温度を本発明にしたがって守るために、仕上圧延前に
所定の温度となるようにデイレ−を行ってもよい。The hot rolling is finish rolled using a tandem rolling mill with five or more rolling machines. In order to increase the total finishing reduction rate according to the present invention and to maintain the finish finishing temperature according to the present invention, a delay may be carried out to reach a predetermined temperature before finishing rolling.
熱延後高温巻取を行うが、熱延フィル両端部は急冷され
るためこれを補う意味で端部がさらに高温となるような
Ｕ字状の巻取温度パターンをとることは好ましい。熱延
コイルは酸洗後冷延され、続いて連続焼鈍される。連続
焼鈍の均熱温度については上述のごとくであるが、保持
時間については通常とられる４０ｓ −１ｓ０ｓでよい
。After hot rolling, high-temperature winding is performed, but since both ends of the hot-rolled film are rapidly cooled, it is preferable to take a U-shaped winding temperature pattern in which the ends become even hotter to compensate for this. The hot-rolled coil is pickled, cold-rolled, and then continuously annealed. The soaking temperature for continuous annealing is as described above, but the holding time may be the usual 40s - 1s0s.
焼鈍後の冷却条件についても特に規定するところではな
く、また通常過時効帯が設けられているが、その温度条
件についても特に規定するところではない。焼鈍後の調
圧は形状矯正のためのやむを得ない範囲にとどめるべき
である。材質からは調圧をしないことが好ましいが、形
状矯正の点を考慮して０．２〜０，８％、好ましくは０
．２〜０．５％が適正調圧率である。There are no particular restrictions on the cooling conditions after annealing, and although an overaging zone is usually provided, there are no particular restrictions on the temperature conditions. Pressure adjustment after annealing should be kept within an unavoidable range for shape correction. Considering the material, it is preferable not to adjust the pressure, but in consideration of shape correction, the pressure should be adjusted by 0.2 to 0.8%, preferably 0.
．． An appropriate pressure regulation rate is 2 to 0.5%.
（実 施 例）
第１表に示す成分の鋼を転炉にて溶製し連続鋳造にてス
ラブとした。このさい、ＲＨ真空脱ガスを用いた。(Example) Steel having the composition shown in Table 1 was melted in a converter and made into a slab by continuous casting. At this time, RH vacuum degassing was used.
続いて第２表に示す熱延および冷延・連続焼鈍条件にて
処理を行い、各コイルの代表部分を材質試験に供した。Subsequently, the coils were processed under the hot rolling, cold rolling and continuous annealing conditions shown in Table 2, and a representative portion of each coil was subjected to a material test.
引張試験はＪＩＳ Ｚ ２２０１，５号試験片を用い、
同Ｚ２２４Ｌ記載の方法にしたがって行った。The tensile test used JIS Z 2201, No. 5 test piece,
This was carried out according to the method described in the same Z224L.
また、耐二次加工性は、まず、−次加工として５０璽■
平底ポンチで絞り比２．２の深絞り加工を行い、続いて
この口を広げる加工を種々温度をかえて行い、脆性−延
性破壊の遷移温度を求めた。In addition, the secondary processing resistance is as follows:
Deep drawing with a drawing ratio of 2.2 was performed using a flat-bottomed punch, followed by widening at various temperatures to determine the brittle-ductile fracture transition temperature.
第３表にコイル長手中心部位の材質試験結果を示す。Table 3 shows the material test results at the longitudinal center of the coil.
木表においてｎとは加工硬化指数で、１０％および２０
％ひずみの応力から０乗則にのっとったとして計算した
。またｒ ａＶｅはＦで面内平均温度ランクフォード値
で、ｒ４５は圧延方向に対し４５°の方向のランクフォ
ード値である。On the wood surface, n is the work hardening index, 10% and 20
It was calculated based on the stress of % strain and according to the 0th power law. Further, raVe is F, which is the Lankford value of the in-plane average temperature, and r45 is the Lankford value in the direction of 45° with respect to the rolling direction.
本発明にしたがった処理ｋｌ、 ７． ９．１３．１
４および１５の鋼は５５％以上の伸び、０，２７以上の
ｎ値と極めて高い延性を示すとともに、ｒ≧２．４５゜
’４５≧２．１５というこれまた極めて高い深絞り性を
示すことがわかる。しかも耐二次加工性も十分低い遷移
温度である。Treatment kl according to the invention, 7. 9.13.1
Steels No. 4 and 15 exhibit extremely high ductility with an elongation of 55% or more and an n value of 0.27 or more, as well as extremely high deep drawability of r≧2.45゜'45≧2.15. I understand. Furthermore, the transition temperature is sufficiently low for secondary processing resistance.
これに対し、成分、熱延条件あるいは冷延・連続焼鈍条
件が本発明条件と異なるその他の処理磁の鋼では、木調
の目的とする高い特性は得られていない。On the other hand, other treated magnetic steels whose composition, hot rolling conditions, or cold rolling/continuous annealing conditions are different from those of the present invention do not have the high properties desired for wood-like appearance.
また、第２図は、第２表、処理Ｎｏ、１４（本発明条件
）および同表処理Ｎｏ、１Ｂ（比較条件）のコイル長手
方向材質分布を示す。前者において仕上終了温度は、８
９５〜９４０℃、また巻取温度はコイル端部で７７０〜
７８０℃、それ以外での部位で７４０〜７５５℃であっ
た。また後者においてはそれぞれ８８５〜９３０℃、７
６０〜７８５℃および７４５〜７６０℃であった。Further, FIG. 2 shows the material distribution in the longitudinal direction of the coil in Table 2, treatment No. 14 (invention conditions) and treatment No. 1B (comparison condition) in the same table. In the former, the finishing temperature is 8
95-940℃, and the winding temperature is 770-940℃ at the coil end.
It was 780°C, and 740-755°C at other parts. In the latter case, 885 to 930℃ and 7
The temperatures were 60-785°C and 745-760°C.
図から明らかなように、本発明にしたがった嵐１４のコ
イルでは、全長にわたり安定して高い７と伸びが得られ
ているのに対し、比較コイルではかなり高い水準にある
ものの材質変動が大きい。As is clear from the figure, the Arashi 14 coil according to the present invention has a stable high elongation of 7 over the entire length, while the comparative coil has a fairly high level of elongation, but there are large variations in the material.
ｓｏｆ、Ａｌ１ （質量割合） Ｔｉ Ｂ ０．０９ ０．１１ ０．０８ ０．２０ ０．０７ ０．１４ ０．１４ ０．０８ ０．００６１ ０．００７３ ０．００３９ ０．００４５ ０．００７５ ｏ、ｏｏａｅ Ｏ，００３７ ０，００７２ ０，０２７ ０，０３３ ０，０３３ ０，０３０ ０，０２９ ０，０２５ ０，０２５ ０，０３１ ０，０５０ ｏ、ｏｅ。sof, Al1 (mass ratio) Ti B 0.09 0.11 0.08 0.20 0.07 0.14 0.14 0.08 0.0061 0.0073 0.0039 0.0045 0.0075 o, ooae O,0037 0,0072 0,027 0,033 0,033 0,030 0,029 0,025 0,025 0,031 0,050 o, oe.
Ｏ，０５２
０，０４３
０，０４１
０，０１４
０，１１２
０，０５０
（発明の効果）
本発明鋼は冷延鋼板として用いられてもよいし、連続焼
鈍条件気メツキや電気系複合メツキを施したメツキ鋼板
として用いられてもよい。また、本鋼成分は溶融亜鉛メ
ツキ性あるいはその後のメツキ層の合金化特性を特に阻
害するものではない。O,052 0,043 0,041 0,014 0,112 0,050 (Effects of the invention) The steel of the present invention may be used as a cold-rolled steel sheet, or may be subjected to continuous annealing condition plating or electrical composite plating. It may also be used as a plated steel plate. Furthermore, the present steel components do not particularly impede the hot-dip galvanizing property or the alloying properties of the subsequent plating layer.
したがって、連続焼鈍条件が満たされる限り、連続焼鈍
溶融亜鉛メツキ鋼板あるいは合金化溶融亜鉛メツキ鋼板
としてもよい。Therefore, as long as the continuous annealing conditions are satisfied, a continuously annealed hot-dip galvanized steel sheet or an alloyed hot-dip galvanized steel sheet may be used.
第１図は、冷延・連続焼鈍後の？値−を、仕上圧延終了
温度および仕上圧延有効ひずみε８４．との関係におい
て示した図表、第２図は実施例に用いたコイルの長手方
向の材質分布を示す図表である。Figure 1 shows the results after cold rolling and continuous annealing. The value - is the finish rolling end temperature and finish rolling effective strain ε84. FIG. 2 is a chart showing the material distribution in the longitudinal direction of the coil used in the example.
Claims (1)
に加熱後熱延するにあたり、粗仕上厚みを４５ｍｍ以上
とし、次式で示される有効ひずみε＿ｅ＿ｆ＿ｆを４５
％以上とり、９５０℃〜８８０℃以上の温度で仕上圧延
を終了した後、１ｓ以内に冷却を開始し２０℃／ｓ以上
の平均冷却速度で８３０℃以下まで冷却を行い続いて６
８０〜８００℃の温度で巻取り、引続き７５〜９０％の
冷延率で冷延を行い、７８０〜８７０℃の温度で連続焼
鈍を行うことを特徴とする加工性の極めて優れた冷延鋼
板の高効率な製造方法。 ただし、 ε＿ｅ＿ｆ＿ｆ＝最終パス圧下率（％）＋１／２最終１
段前パス圧下率（％）＋１／４最終２段前パス 圧下率（％）[Claims] In mass%, C: 0.0040% or less, N: 0.0040% or less, Mn: 0.05 to 0.4%, S: 0.015% or less, acid-soluble Al: Steel consisting of 0.005 to 0.100%, Ti: 0.04 to 0.085%, B: 0.0001 to 0.0010%, and the remainder being unavoidable impurity elements is heated to 1200°C or less and then hot rolled. For this purpose, the rough finishing thickness is set to 45 mm or more, and the effective strain ε_e_f_f shown by the following formula is set to 45 mm.
% or more and finish rolling at a temperature of 950°C to 880°C or more, start cooling within 1 s, cool down to 830°C or less at an average cooling rate of 20°C/s or more, and continue with 6
A cold-rolled steel sheet with extremely excellent workability, characterized by being rolled at a temperature of 80 to 800°C, followed by cold rolling at a cold rolling rate of 75 to 90%, and continuous annealing at a temperature of 780 to 870°C. Highly efficient manufacturing method. However, ε_e_f_f = final pass rolling reduction rate (%) + 1/2 final 1
Pre-stage pass reduction rate (%) + 1/4 final 2-stage pre-pass reduction rate (%)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2158586A JPH07103423B2 (en) | 1990-06-19 | 1990-06-19 | Highly efficient manufacturing method of cold rolled steel sheet with extremely excellent workability |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2158586A JPH07103423B2 (en) | 1990-06-19 | 1990-06-19 | Highly efficient manufacturing method of cold rolled steel sheet with extremely excellent workability |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0452229A true JPH0452229A (en) | 1992-02-20 |
| JPH07103423B2 JPH07103423B2 (en) | 1995-11-08 |
Family
ID=15674930
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2158586A Expired - Fee Related JPH07103423B2 (en) | 1990-06-19 | 1990-06-19 | Highly efficient manufacturing method of cold rolled steel sheet with extremely excellent workability |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH07103423B2 (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5997664A (en) * | 1996-04-01 | 1999-12-07 | Nkk Corporation | Method for producing galvanized steel sheet |
| KR100530057B1 (en) * | 2001-11-26 | 2005-11-22 | 주식회사 포스코 | Method for Manufacturing Cold Rolled Steel Sheet with Superior Workability and Secondary Working Embrittlement Resistance |
| KR100530059B1 (en) * | 2001-11-26 | 2005-11-22 | 주식회사 포스코 | Method for Manufacturing Cold Rolled Steel Sheet with Superior Drawability, Bake Hardenability and Secondary Working Embrittlement Resistance |
| US9017492B2 (en) | 2003-11-05 | 2015-04-28 | Nippon Steel & Sumitomo Metal Corporation | Thin gauge steel sheet excellent in surface conditions, formability, and workability and method for producing the same |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61276930A (en) * | 1985-05-31 | 1986-12-06 | Kawasaki Steel Corp | Production of cold rolled dead soft steel sheet having good elongation and deep drawability |
| JPS63100134A (en) * | 1986-10-15 | 1988-05-02 | Kawasaki Steel Corp | Manufacture of cold rolled steel sheet for extra deep drawing of thick product |
| JPH01191748A (en) * | 1988-01-26 | 1989-08-01 | Nippon Steel Corp | Manufacture of cold rolled steel sheet for press forming excellent in material homogeneity in coil |
-
1990
- 1990-06-19 JP JP2158586A patent/JPH07103423B2/en not_active Expired - Fee Related
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61276930A (en) * | 1985-05-31 | 1986-12-06 | Kawasaki Steel Corp | Production of cold rolled dead soft steel sheet having good elongation and deep drawability |
| JPS63100134A (en) * | 1986-10-15 | 1988-05-02 | Kawasaki Steel Corp | Manufacture of cold rolled steel sheet for extra deep drawing of thick product |
| JPH01191748A (en) * | 1988-01-26 | 1989-08-01 | Nippon Steel Corp | Manufacture of cold rolled steel sheet for press forming excellent in material homogeneity in coil |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5997664A (en) * | 1996-04-01 | 1999-12-07 | Nkk Corporation | Method for producing galvanized steel sheet |
| KR100530057B1 (en) * | 2001-11-26 | 2005-11-22 | 주식회사 포스코 | Method for Manufacturing Cold Rolled Steel Sheet with Superior Workability and Secondary Working Embrittlement Resistance |
| KR100530059B1 (en) * | 2001-11-26 | 2005-11-22 | 주식회사 포스코 | Method for Manufacturing Cold Rolled Steel Sheet with Superior Drawability, Bake Hardenability and Secondary Working Embrittlement Resistance |
| US9017492B2 (en) | 2003-11-05 | 2015-04-28 | Nippon Steel & Sumitomo Metal Corporation | Thin gauge steel sheet excellent in surface conditions, formability, and workability and method for producing the same |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH07103423B2 (en) | 1995-11-08 |
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