JPS6152217B2 - - Google Patents
Info
- Publication number
- JPS6152217B2 JPS6152217B2 JP14634981A JP14634981A JPS6152217B2 JP S6152217 B2 JPS6152217 B2 JP S6152217B2 JP 14634981 A JP14634981 A JP 14634981A JP 14634981 A JP14634981 A JP 14634981A JP S6152217 B2 JPS6152217 B2 JP S6152217B2
- Authority
- JP
- Japan
- Prior art keywords
- less
- steel
- cold rolling
- rolled
- 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.)
- Expired
Links
- 229910000831 Steel Inorganic materials 0.000 claims description 49
- 239000010959 steel Substances 0.000 claims description 49
- 238000005097 cold rolling Methods 0.000 claims description 41
- 238000004804 winding Methods 0.000 claims description 17
- 238000000034 method Methods 0.000 claims description 14
- 229910052757 nitrogen Inorganic materials 0.000 claims description 13
- 238000000137 annealing Methods 0.000 claims description 12
- 238000004519 manufacturing process Methods 0.000 claims description 12
- 229910052698 phosphorus Inorganic materials 0.000 claims description 11
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical group [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 6
- 239000010960 cold rolled steel Substances 0.000 claims description 6
- 239000012535 impurity Substances 0.000 claims description 3
- 229910052742 iron Inorganic materials 0.000 claims description 3
- 229910052799 carbon Inorganic materials 0.000 claims description 2
- 238000005098 hot rolling Methods 0.000 description 11
- 238000005096 rolling process Methods 0.000 description 8
- 239000000463 material Substances 0.000 description 7
- 238000007796 conventional method Methods 0.000 description 5
- 238000001816 cooling Methods 0.000 description 5
- 239000000203 mixture Substances 0.000 description 5
- 229910000655 Killed steel Inorganic materials 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 238000010438 heat treatment Methods 0.000 description 4
- 238000001953 recrystallisation Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 3
- 238000009849 vacuum degassing Methods 0.000 description 3
- 230000007423 decrease Effects 0.000 description 2
- 238000005265 energy consumption Methods 0.000 description 2
- 238000011156 evaluation Methods 0.000 description 2
- 230000001771 impaired effect Effects 0.000 description 2
- 238000002791 soaking Methods 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 229910001209 Low-carbon steel Inorganic materials 0.000 description 1
- 238000005275 alloying Methods 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 238000009749 continuous casting Methods 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 238000005554 pickling Methods 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 239000000523 sample Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000004381 surface treatment Methods 0.000 description 1
- 238000009864 tensile test Methods 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 239000005028 tinplate Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING 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
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/04—Modifying 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
- C21D8/0421—Modifying 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 characterised by the working steps
- C21D8/0426—Hot rolling
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING 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
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/04—Modifying 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
- C21D8/0421—Modifying 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 characterised by the working steps
- C21D8/0436—Cold rolling
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING 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
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/04—Modifying 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
- C21D8/0447—Modifying 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 characterised by the heat treatment
- C21D8/0473—Final recrystallisation annealing
Landscapes
- 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
本発明は冷間圧延性能が優れ、かつ深絞り性の
優れた冷延鋼板を連続焼鈍で製造する方法に関す
るものである。
従来、良加工性冷延鋼板の製造は鋼板の材質特
性に主眼をおき、鋼の成分系、製造条件が決定さ
れていた。近年冷間圧延の高速化、ホツトストリ
ツプ圧延の省エネルギー、高生産性を計るため熱
延板厚増の傾向にあり、成品の材質特性と冷延時
の圧延消費エネルギー低下、冷延時の板破断の低
いことを兼備した鋼板の製造法の開発が望まれて
いる。
一方、連続焼鈍による深絞り用鋼板の製造法は
種々報告されているが、下記の三方法に大別でき
る。
(イ) 極低Ｃ鋼にTi、Nb等の炭窒化物元素を添加
した侵入型元素フリーステイール
(ロ) 極低Ｃ鋼
(ハ) 通常の極軟鋼成分で熱延時に高温捲取をした
もの
まず(イ)では極低Ｃ（0.005％程度）にするため
真空脱ガス等の特殊な工程を必要とし、加えて
Ti、Nb等の添加のため合金代を必要とするた
め、必然的に製造コストが高くなる。(ロ)ではやは
り極低Ｃ（0.004％程度）までＣ量を低下するた
め(イ)と同様に鋼の精錬時に真空脱ガス等の特殊な
工程を必要とするため、やはりコストアツプとな
る。(ハ)の高温捲取による方法は、高温捲取時にコ
イルの位置による冷却速度の差に起因するコイル
長手方向、巾方向の材質バラツキが大きくなり、
深絞り性の良好な鋼板を製造する場合は歩留りが
低下する。また高温捲取りにより酸化皮膜が厚く
なり、熱延板の酸洗性が低下するという問題があ
る。
本発明者らは冷間圧延性能が良好で、しかも深
絞り性の優れ且つ上記欠点を解決した冷延鋼板
を、連続焼鈍により製造する方法を種々研究した
結果、本発明を完成した。
即ち本発明の骨子は重量％としてＣ：0.07％以
下、Mn：0.40％以下、Al：0.005〜0.050％、Ｎ：
0.0025％以下、Ｐ：0.010％以下としかつＰ＋
5N：0.0170％以下、残部が鉄および不可避的不
純物からなる組成の鋼をAr3点以上で熱間圧延
し、かつ575℃以上で捲取り、これを50％以上の
冷延率で冷延した後、連続焼鈍法で再結晶温度以
上、A3点以下の温度範囲で５分以下の再結晶焼
鈍し、急冷して過時効処理を行なうことを特徴と
する、深絞り性のすぐれた冷延鋼板の製造法にあ
る。
以下本発明について詳細に説明する。
先ず本発明を構成する鋼成分について説明す
る。
Ｃは従来から含有量が低いほど鋼板は軟質化
し、加工性が向上することが知られている。しか
し0.010％程度以下にＣを低くするためには溶鋼
を真空脱ガス処理などの処理が必要でコスト上昇
をもたらす。したがつてＣ含有量の下限は0.01％
である。Ｃ含有量が0.07％を超えるとＣにより硬
質化し、本発明の材質的な特徴および冷間圧延性
能が失われる。好ましい範囲は0.01〜0.05％であ
る。
本発明を構成する鋼組成の中で最も重要な構成
要件は、ＰおよびＮを密接不可分の関係に特定す
ることである。
まずＰおよびＮ量をそれぞれＰ；0.010％以
下、Ｎ；0.0025％以下に特定し、Ｐ＋5N0.0170
％の条件式を満足しなければならない。これらの
条件は深絞り性および冷間圧延性能を同時に良好
ならしめるためのものである。以下これをより詳
細に説明する。
ＰおよびＮ量の限定は本発明では極めて重要な
意義を有する。第１図は１例としてＣ：0.02〜
0.040％、Mn：0.10〜0.25％、Al：0.02〜0.04％
の組成の鋼のＰ量、Ｎ量と値および伸びの関係
を示したもので、第２図はＰ、Ｎ量と冷間圧延性
能の関係を示したもので、いずれも多数の実験の
平均値の等高線で表示している。
他の製造条件は次の通りである。
スラブ加熱温度 1050〜1250℃
熱延仕上温度 ＞850℃
捲取温度 575〜650℃
冷延率 75〜85％
焼鈍条件 700℃×１分＋400℃
×３分
調質圧延条件 1.2％
第１図からわかるようにＰ量：0.010％以下Ｎ
量：0.0025％以下かつＰ＋5N0.0170になれば、
加工性と良い相関のある値（実線）、伸び（破
線）が良好となる。特にＰ：0.007％以下、Ｎ：
0.0020％以下の領域で特に顕著な効果を示す。さ
らにＮが0.0015％以下になると、最高級の深絞り
性を発揮する。捲取温度が575〜650℃と比較的低
温捲取にもかかわらず、値、伸びの絶対値も高
くなつている。
第２図からわかるようにＰ量：0.010％、Ｎ
量：0.0025％以下、かつＰ＋5N0.0170％の領域
は冷間圧延時の板破断が極めて少なくなる。また
実施例に示したように、冷延消費エネルギーも従
来法より小さい。本発明では後述のように冷延時
の圧延率は従来より高い方が好ましいので、この
冷延特性が優れていることの工業的意義は大き
い。特に図中に示したようにＰ：0.007％以下、
Ｎ量：0.0020％以下で顕著である。
なお板破断特性は実験室冷間圧延機を用いて板
厚4.0mmの熱延板の端部に切欠ノツチを入れ板厚
0.6mm（冷延率85％）まで圧延した時の板破断圧
延本数（合計20本）で評価した。
従つてＰ量およびＮ量は鋼板の加工性および冷
間圧延性能の両特性を考慮して上述のとおり規定
した。
Mnは熱間圧延時のＳによる熱間脆性を防止す
るため0.05％程度は必要であるが、通常行なわれ
ているMn／Ｓ10の条件を安定して満足するた
めに、下限を0.10％とすることが好ましい。一方
0.40％を超えるとＣと同様に本発明の特徴をそこ
なう。深絞り性のより優れた鋼板を得たい場合
は、0.30％以下にすることが好ましい。
Alはキルド鋼とするため少なくとも0.005％必
要である。一方Al量が0.05％を超えると鋼板が若
干硬質化しまたコスト上昇をもたらす。好ましい
範囲は0.010〜0.040％である。
Ｓについては熱間脆性を防止するため通常行な
われているように、Mn／Ｓ10とするが、加工
性の点からＳは0.015％以下とすることが好まし
い。
本発明の成分系は上記の通りであるが、本発明
の特徴を向上させるためＢ、Cr等の炭窒化物形
成元素を、通常行われる範囲内で適宜添加しても
良い。
鋼の加工性を向上のため、Alキルド鋼にＢを
添加する方法も報告されているが（特公51−
29696号公報）、Ｂは本発明の効果を失なわず、よ
り一層の加工性向上と冷間圧延性能の向上を可能
とする。Ｂを添加する場合はＢ／Ｎ1.5以下と
する。
またCr添加の場合は通常行なわれるように0.10
％以下とする。
本発明の鋼は通常行なわれる転炉等で溶製され
る。溶製された溶鋼は造塊、分塊または連続鋳造
されて鋼片とされる。熱間圧延条件は熱延仕上温
度が鋼のAr3点以上であれば本発明の特徴を失わ
ない。したがつて熱延のためのスラブ加熱温度は
省エネルギーのため低くしてもさしつかえない。
また連続鋳造または分塊圧延された熱鋼片を直接
熱間圧延しても良い。また連続鋳造または分塊圧
延された熱鋼片を加熱炉に装入するホツトチヤー
ジを行つても良い。
本発明の深絞り性が良好であるという特徴をよ
り発揮するためには、仕上熱延を1000℃以下Ar3
点以上で行ない、熱延終了後直ちに30℃／sec以
上の強制冷却をすることが好ましい。仕上入口温
度を1000℃以下にすれば鋼板の値が向上する。
この効果をより発揮するためにはスラブ加熱温度
を1100℃以下とすることが好ましい。
深絞り用鋼板に必要とされる値1.4以上を確
保するためには本発明方法では捲取温度は575℃
以上であれば良い。第３図にＣ：0.03％Mn：
0.20％、Ｐ：0.007％、Ｎ：0.0015％、Al：0.030
％の鋼の捲取温度と値の関係を示す。
なお焼鈍は700℃×１分＋400℃×３分である。
第３図からわかるように捲取温度が575℃以下
になると本発明の特徴の一つである値が低下す
る。一方捲取温度が575℃より高くなると値も
より高くなる。また従来のように700℃程度の高
温捲取の必要性は必ずしもなく、630℃未満の捲
取でも良好な深絞り性を有する。また実施例で詳
述するように高温捲取（例えば750℃捲取）でも
従来法に比較してコイル長手方向、巾方向の材質
バラツキが極めて少なくなる。
熱延されたコイルは続いて脱スケールされ、冷
間圧延に供される。冷間圧延率は従来行なわれて
いるように50％以上の冷間圧延が施されるが、本
発明鋼では冷間圧延率が通常の鋼より高い方が加
工性が向上することが確認された。この結果を第
４図に示す。
第４図の供試材の化学成分および熱延条件を第
１表に示す。
The present invention relates to a method for producing a cold rolled steel sheet with excellent cold rolling performance and deep drawability by continuous annealing. Conventionally, in the production of cold-rolled steel sheets with good workability, the main focus has been on the material properties of the steel sheet, and the composition of the steel and manufacturing conditions have been determined. In recent years, there has been a trend toward increasing the thickness of hot-rolled sheets in order to increase the speed of cold rolling, save energy in hot strip rolling, and increase productivity. There is a desire to develop a manufacturing method for steel sheets that combines these features. On the other hand, various methods for manufacturing deep drawing steel sheets by continuous annealing have been reported, but they can be broadly classified into the following three methods. (a) Interstitial element freesteel made by adding carbonitride elements such as Ti and Nb to ultra-low C steel (b) Ultra-low C steel (c) Ultra-low C steel made of ordinary ultra-mild steel and subjected to high-temperature winding during hot rolling. First, (a) requires special processes such as vacuum degassing to achieve extremely low C (about 0.005%), and in addition,
Since alloying costs are required to add Ti, Nb, etc., manufacturing costs inevitably increase. In (b), the C content is reduced to an extremely low C level (approximately 0.004%), which requires a special process such as vacuum degassing during steel refining, as in (b), resulting in an increase in costs. In the method (c) of high-temperature winding, there is a large variation in the material in the longitudinal and width directions of the coil due to the difference in cooling rate depending on the position of the coil during high-temperature winding.
When manufacturing a steel plate with good deep drawability, the yield decreases. Further, there is a problem in that the oxide film becomes thick due to high-temperature rolling, and the pickling properties of the hot-rolled sheet deteriorate. The present inventors have completed the present invention as a result of research into various methods for manufacturing cold rolled steel sheets by continuous annealing that have good cold rolling performance, excellent deep drawability, and solve the above-mentioned drawbacks. That is, the main points of the present invention are as follows: C: 0.07% or less, Mn: 0.40% or less, Al: 0.005 to 0.050%, N:
0.0025% or less, P: 0.010% or less and P+
5N: Steel with a composition of 0.0170% or less, the balance consisting of iron and unavoidable impurities, was hot rolled at 3 points or more of Ar, rolled at 575℃ or more, and then cold rolled at a cold rolling rate of 50% or more. After that, a cold rolled product with excellent deep drawability is subjected to continuous annealing for 5 minutes or less at a temperature range above the recrystallization temperature and below A 3 points, followed by rapid cooling and overaging treatment. It is in the manufacturing method of steel plates. The present invention will be explained in detail below. First, the steel components constituting the present invention will be explained. It has been known that the lower the C content, the softer the steel sheet becomes and the better the workability is. However, in order to lower the C content to about 0.010% or less, the molten steel needs to be subjected to vacuum degassing treatment, which increases costs. Therefore, the lower limit of C content is 0.01%
It is. When the C content exceeds 0.07%, the steel becomes hard due to C, and the material characteristics and cold rolling performance of the present invention are lost. The preferred range is 0.01-0.05%. The most important component of the steel composition constituting the present invention is to specify P and N in a close and inseparable relationship. First, specify the P and N amounts as P: 0.010% or less and N: 0.0025% or less, respectively, and P+5N0.0170
% conditional expression must be satisfied. These conditions are intended to simultaneously improve deep drawability and cold rolling performance. This will be explained in more detail below. Limiting the amounts of P and N has extremely important significance in the present invention. Figure 1 shows an example of C: 0.02~
0.040%, Mn: 0.10~0.25%, Al: 0.02~0.04%
Figure 2 shows the relationship between the P content, N content and value and elongation of steel with the composition. Figure 2 shows the relationship between the P and N content and cold rolling performance. Displayed as value contour lines. Other manufacturing conditions are as follows. Slab heating temperature 1050~1250℃ Hot rolling finishing temperature >850℃ Winding temperature 575~650℃ Cold rolling rate 75~85% Annealing conditions 700℃ x 1 minute + 400℃ x 3 minutes Skin pass rolling conditions 1.2% From Figure 1 As you can see, P amount: 0.010% or less N
Amount: 0.0025% or less and P+5N0.0170,
Values that have a good correlation with workability (solid line) and elongation (broken line) are good. Especially P: 0.007% or less, N:
Particularly remarkable effects are shown in the region of 0.0020% or less. Furthermore, when the N content is 0.0015% or less, it exhibits the highest quality deep drawability. Despite the relatively low winding temperature of 575 to 650°C, the absolute values of value and elongation are high. As shown in Figure 2, P amount: 0.010%, N
In the region where the amount is 0.0025% or less and P+5N is 0.0170%, plate breakage during cold rolling is extremely small. Furthermore, as shown in the examples, the energy consumption of cold rolling is also smaller than that of the conventional method. In the present invention, as will be described later, it is preferable that the rolling rate during cold rolling is higher than that of the conventional method, so the industrial significance of this excellent cold rolling property is great. In particular, as shown in the figure, P: 0.007% or less,
N content: noticeable at 0.0020% or less. The plate breaking characteristics were determined using a laboratory cold rolling machine by cutting notches at the ends of hot-rolled plates with a thickness of 4.0 mm.
The evaluation was based on the number of plates that broke when rolled to 0.6 mm (cold rolling ratio of 85%) (total of 20 pieces). Therefore, the amount of P and the amount of N were determined as described above in consideration of both the workability and cold rolling performance characteristics of the steel sheet. Approximately 0.05% Mn is necessary to prevent hot embrittlement caused by S during hot rolling, but the lower limit is set at 0.10% in order to stably satisfy the usual Mn/S10 condition. It is preferable. on the other hand
If it exceeds 0.40%, like C, the characteristics of the present invention will be impaired. If you want to obtain a steel plate with better deep drawability, it is preferably 0.30% or less. At least 0.005% of Al is required to make the steel a killed steel. On the other hand, if the Al content exceeds 0.05%, the steel plate becomes slightly hard and costs increase. The preferred range is 0.010-0.040%. As for S, Mn/S10 is used as usual to prevent hot embrittlement, but from the viewpoint of workability, it is preferable that S be 0.015% or less. The component system of the present invention is as described above, but in order to improve the characteristics of the present invention, carbonitride forming elements such as B and Cr may be added as appropriate within the usual range. In order to improve the workability of steel, a method of adding B to Al-killed steel has also been reported (Japanese Patent Publication No. 51-
No. 29696) and B enable further improvement in workability and cold rolling performance without losing the effects of the present invention. When B is added, the B/N should be 1.5 or less. In addition, in the case of Cr addition, 0.10
% or less. The steel of the present invention is melted in a conventional converter or the like. The produced molten steel is ingot-formed, bloomed, or continuously cast into steel billets. As for the hot rolling conditions, the features of the present invention are not lost as long as the hot rolling finishing temperature is at least 3 points of Ar of the steel. Therefore, the slab heating temperature for hot rolling may be lowered to save energy.
Alternatively, hot steel slabs that have been continuously cast or bloomed may be directly hot rolled. Alternatively, hot charging may be carried out by charging continuously cast or bloom-rolled hot steel billets into a heating furnace. In order to take full advantage of the good deep drawability of the present invention, the finish hot rolling must be carried out at 1000°C or below in Ar 3
It is preferable to carry out forced cooling at 30° C./sec or higher immediately after hot rolling is completed. If the finishing inlet temperature is kept below 1000℃, the value of the steel plate will improve.
In order to better exhibit this effect, it is preferable that the slab heating temperature be 1100°C or less. In order to ensure a value of 1.4 or higher, which is required for deep drawing steel sheets, the winding temperature in the method of the present invention is 575℃.
Any above is fine. Figure 3 shows C: 0.03%Mn:
0.20%, P: 0.007%, N: 0.0015%, Al: 0.030
The relationship between the rolling temperature and value of steel in % is shown. The annealing was performed at 700°C for 1 minute + 400°C for 3 minutes. As can be seen from FIG. 3, when the winding temperature becomes 575° C. or lower, the value, which is one of the characteristics of the present invention, decreases. On the other hand, when the winding temperature is higher than 575°C, the value becomes higher. Further, there is no need for high-temperature winding of about 700°C as in the past, and good deep drawability is achieved even when winding is performed at temperatures below 630°C. Furthermore, as will be described in detail in the Examples, even when winding at high temperatures (for example, winding at 750° C.), variations in the material in the lengthwise and widthwise directions of the coil are extremely reduced compared to the conventional method. The hot rolled coil is subsequently descaled and subjected to cold rolling. Although cold rolling is performed at a cold rolling rate of 50% or more as conventionally done, it has been confirmed that the workability of the steel of the present invention is improved when the cold rolling rate is higher than that of ordinary steel. Ta. The results are shown in FIG. Table 1 shows the chemical composition and hot rolling conditions of the sample material shown in FIG.
【表】
なお冷延鋼板は750℃×１分＋400℃×３分の再
結晶焼鈍を行つた。
第４図からわかるように、本発明法のＡ鋼は
値も高く、値が最高となる冷延率が、約87％程
度にあることがわかる。冷延率が70％以上になれ
ば1.4以上の値が得られる。したがつて本発明
の特徴の一つである高値を得るためには冷延率
を70％以上、90％以下とすることが好ましい。
従来冷延率と値の関係について多数の報告が
あるが、80％以上の冷延率で値が最大となるの
は、(1)極低Ｃ鋼（Ｃ：0.010％以下）(2)極低Ｃ鋼
にTi又はNbを添加したもの、(3)低Ｃ−Al−キル
ド鋼の750℃程度の高温捲取したものがある。
Ｐ、Ｎを低くした低Ｃ−Al−キルド鋼で600℃程
度の捲取温度で、値の最大となる冷延率が80％
以上になるのは新しい発見である。
一方本発明法以外の鋼Ｂ、Ｃ、Ｄは値の絶対
値も低く、値の最大となる冷延率も75％程度で
ある。
本発明法の場合冷間圧延性能がすぐれているの
で、冷間圧延率を70〜90％に高めてもなんら支障
をきたさない。
焼鈍は連続焼鈍法により再結晶温度以上、A3
点以下で均熱し、急冷して過時効処理を施すが通
常行なわれる連続焼鈍法にすべて適用可能であ
る。代表的焼鈍条件は650〜850℃で５分以下の再
結晶処理をした後冷却し、200〜450℃で10分以下
の過時効処理が施される。深絞り性をより向上さ
せる場合は、均熱温度を700℃以上にすることが
好ましい。
焼鈍された鋼板は必要に応じて調質圧延され成
品に供される。
また本発明の方法で製造された鋼板は、表面処
理されても本発明の特徴をなんら損わないので、
ブリキ、Znメツキ、ターンメツキ鋼板にも適用
される。
実施例 １
第２表に示す鋼を転炉にて溶製し、連続鋳造に
よつてスラブにされ、1050〜1200℃で加熱後第２
表に示す条件で4.0mmまで熱延し、ついで脱スケ
ール後、0.8mmまで冷間圧延し、連続焼鈍により
700℃×１分の再結晶焼鈍後急冷し400℃×１分の
過時効処理を施した後1.3％の調質圧延をした。
製造された鋼板の機械的性質および冷間圧延時
の冷間圧延性能を第２表に示した。冷間圧延性能
で冷間圧延消費エネルギーは、従来法（通常の低
炭Alキルド鋼）の平均値との比で示した。又板
破断特性は別途実験室冷間圧延機を用いて、熱延
板の端部に切欠きノツチを入れて板厚0.6mm（冷
延率85％）まで圧延した時の板破断圧延本数（合
計20本）で評価した。
引張試験片はJIS5号試験片を用い、鋼板の特性
はコイル全長の平均値で示したが、値はコイル
のＭ部（コイル長手方向の中心）とコイルＢ部
（コイル長手方向の最後尾）の差＝Ｍ−Ｂも
示した。
本発明の範囲内のものは捲取温度が630℃未満
でも降伏点が低く、伸びが高く、しかも値が高
く、加工性が優れており、冷間圧延性能がすぐれ
ていることがわかる。
コイルNo.ＥとＦは熱延の仕上圧延条件以外は同
一であるが、熱延仕上入口温度が1000℃以下であ
るコイルNo.Ｆの値がすぐれていることがわか
る。比較材の捲取温度：750℃のコイルNo.Ｎは
値も高く、伸びも良好であるが、Ｍ−Ｂが大
きく、コイル長手方向の材質バラツキが大きくな
つている。
一方本発明法の捲取温度が750℃であるコイル
No.Ｈは値の絶対値も高くなり、（コイルNo.Ａと
比較）、Ｍ−Ｂも小さくなつており本発明で
は捲取温度を高くしても従来法のようにコイル内
の材質バラツキが大きくないことがわかる。[Table] The cold-rolled steel sheets were recrystallized annealed at 750°C for 1 minute + 400°C for 3 minutes. As can be seen from FIG. 4, steel A manufactured by the present invention has a high value, and the cold rolling rate at which the value is the highest is about 87%. If the cold rolling rate is 70% or more, a value of 1.4 or more can be obtained. Therefore, in order to obtain a high value, which is one of the characteristics of the present invention, it is preferable that the cold rolling rate is 70% or more and 90% or less. There have been many reports on the relationship between cold rolling reduction and value, but the ones that have the highest value at a cold rolling reduction of 80% or more are (1) ultra-low C steel (C: 0.010% or less) (2) ultra-low C steel (C: 0.010% or less) There are low C steels with Ti or Nb added, and (3) low C-Al-killed steels rolled at a high temperature of about 750°C.
Low C-Al-killed steel with low P and N content has a maximum cold rolling rate of 80% at a winding temperature of around 600℃.
The above is a new discovery. On the other hand, steels B, C, and D produced by the method of the present invention have low absolute values, and the cold rolling ratio at which the values reach the maximum is about 75%. Since the method of the present invention has excellent cold rolling performance, no problem occurs even if the cold rolling rate is increased to 70 to 90%. Annealing is performed by continuous annealing method above the recrystallization temperature, A 3
It is applicable to all conventional continuous annealing methods, which involve soaking at a temperature below a temperature of 100%, followed by rapid cooling and overaging treatment. Typical annealing conditions include recrystallization at 650 to 850°C for 5 minutes or less, followed by cooling, and overaging at 200 to 450°C for 10 minutes or less. In order to further improve deep drawability, it is preferable to set the soaking temperature to 700°C or higher. The annealed steel plate is subjected to skin pass rolling as required and is then used as a finished product. Furthermore, even if the steel plate manufactured by the method of the present invention is subjected to surface treatment, the characteristics of the present invention will not be impaired in any way.
Also applicable to tinplate, Zn plated, and turn plated steel sheets. Example 1 The steel shown in Table 2 was melted in a converter, made into a slab by continuous casting, heated at 1050 to 1200°C, and then
Hot rolled to 4.0mm under the conditions shown in the table, then descaled, cold rolled to 0.8mm, and continuously annealed.
After recrystallization annealing at 700°C for 1 minute, it was rapidly cooled and over-aged at 400°C for 1 minute, followed by 1.3% temper rolling. Table 2 shows the mechanical properties and cold rolling performance of the produced steel sheets. In terms of cold rolling performance, cold rolling energy consumption is expressed as a ratio to the average value of conventional method (normal low carbon Al killed steel). In addition, the plate breakage characteristics are determined by the number of sheets rolled at breakage when a hot-rolled plate is rolled to a thickness of 0.6 mm (cold rolling ratio 85%) using a separate laboratory cold rolling mill with notches at the ends of the hot-rolled plate. A total of 20 pieces) were used for evaluation. A JIS No. 5 test piece was used as the tensile test piece, and the properties of the steel plate were shown as the average value of the entire length of the coil, but the values are for the M part of the coil (the center in the longitudinal direction of the coil) and the coil B part (the last end in the longitudinal direction of the coil). The difference between = M - B is also shown. It can be seen that those within the range of the present invention have a low yield point, a high elongation, and a high value even at a winding temperature of less than 630°C, and have excellent workability and excellent cold rolling performance. Coil Nos. E and F are the same except for the finish rolling conditions of hot rolling, but it can be seen that the value of coil No. F, where the hot rolling finishing inlet temperature is 1000° C. or less, is superior. Coil No. N of the comparative material with a winding temperature of 750°C has a high value and good elongation, but has a large M-B and a large variation in material in the longitudinal direction of the coil. On the other hand, a coil whose winding temperature is 750℃ according to the present invention
For No.H, the absolute value of the value is also higher (compared to coil No.A), and M-B is also smaller.In the present invention, even if the winding temperature is increased, unlike the conventional method, there is no variation in the material inside the coil. It can be seen that is not large.
【表】【table】
第１図はＰ、Ｎ量と鋼板の値、伸びの関係を
示す図、第２図はＰ、Ｎ量と冷間圧延性能の関係
を示す図、第３図は捲取温度と鋼板の値の関係
を示す図、第４図は冷延率と値の関係を示す図
である。
Figure 1 is a diagram showing the relationship between P and N contents, steel sheet values, and elongation. Figure 2 is a diagram showing the relationship between P and N contents and cold rolling performance. Figure 3 is a diagram showing the relationship between coiling temperature and steel sheet value. FIG. 4 is a diagram showing the relationship between the cold rolling rate and the value.
Claims (1)
以下、Al：0.005〜0.050％、Ｎ：0.0025％以下、
Ｐ：0.010％以下とし、かつＰ＋5N：0.0170％以
下、残部が鉄および不可避的不純物からなる組成
の鋼をAr3点以上で熱間圧延し、かつ575℃以上
で捲取り、これを50％以上の冷延率で冷延した
後、連続焼鈍法で再結晶温度以上、A3点以下の
温度範囲で５分以下の再結晶焼鈍し急冷して過時
効処理を行なうことを特徴とする深絞り性のすぐ
れた冷延鋼板の製造法。 ２ 重量％として、Ｃ：0.050％以下、Mn：0.30
％以下、Al：0.005〜0.050％、Ｎ：0.0020％以
下、Ｐ：0.010％以下とし、かつＰ＋5N：0.0170
％以下、残部が鉄および不可避的不純物からなる
組成の鋼をAr3点以上で熱間圧延し、かつ575℃
以上で捲取り、これを70％以上90％以下の冷延率
で冷延した後、連続焼鈍法で650〜850℃の温度範
囲で５分以下の再結晶焼鈍を施した後急冷して
200〜450℃の温度範囲で10分以下の過時効処理を
行なうことを特徴とする特許請求の範囲第１項記
載の深絞り性の優れた冷延鋼板の製造法。[Claims] 1. C: 0.07% or less, Mn: 0.40% as weight%
Below, Al: 0.005 to 0.050%, N: 0.0025% or less,
P: 0.010% or less, P+5N: 0.0170% or less, the balance is iron and inevitable impurities, and the steel is hot rolled at 3 or more Ar points and rolled at 575°C or more, and the steel is rolled at 50% or more. After cold rolling at a cold rolling rate of A method for producing cold-rolled steel sheets with excellent properties. 2 As weight%, C: 0.050% or less, Mn: 0.30
% or less, Al: 0.005 to 0.050%, N: 0.0020% or less, P: 0.010% or less, and P+5N: 0.0170
% or less, with the balance consisting of iron and unavoidable impurities, hot rolled at 3 points or more of Ar, and at 575°C.
After winding it up and cold rolling it at a cold rolling rate of 70% to 90%, it is recrystallized annealed for 5 minutes or less at a temperature range of 650 to 850°C using a continuous annealing method, and then rapidly cooled.
2. The method for producing a cold-rolled steel sheet with excellent deep drawability according to claim 1, characterized in that an overaging treatment is carried out at a temperature range of 200 to 450° C. for 10 minutes or less.
Priority Applications (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14634981A JPS5848634A (en) | 1981-09-18 | 1981-09-18 | Production of cold rolled steel plate having excellent deep drawability |
| EP82108598A EP0075292B2 (en) | 1981-09-18 | 1982-09-17 | Method for producing a cold rolled steel sheet |
| DE8282108598T DE3271669D1 (en) | 1981-09-18 | 1982-09-17 | Method for producing a cold rolled steel sheet |
| US06/776,097 US4627881A (en) | 1981-09-18 | 1985-09-16 | Cold rolled steel sheet having excellent press formability and method for producing the same |
| US06/894,255 US4678522A (en) | 1981-09-18 | 1986-08-07 | Cold rolled steel sheet having excellent press formability and method for producing the same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14634981A JPS5848634A (en) | 1981-09-18 | 1981-09-18 | Production of cold rolled steel plate having excellent deep drawability |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5848634A JPS5848634A (en) | 1983-03-22 |
| JPS6152217B2 true JPS6152217B2 (en) | 1986-11-12 |
Family
ID=15405693
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP14634981A Granted JPS5848634A (en) | 1981-09-18 | 1981-09-18 | Production of cold rolled steel plate having excellent deep drawability |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5848634A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59173222A (en) * | 1983-03-24 | 1984-10-01 | Nippon Steel Corp | Manufacture of soft surface treating stock sheet |
| JPS6130628A (en) * | 1984-07-23 | 1986-02-12 | Nippon Kokan Kk <Nkk> | Manufacture of low carbon aluminum killed steel strip |
-
1981
- 1981-09-18 JP JP14634981A patent/JPS5848634A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5848634A (en) | 1983-03-22 |
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