JPS5910976B2 - Method for manufacturing high-strength cold-rolled steel sheet with excellent deep drawability - Google Patents
Method for manufacturing high-strength cold-rolled steel sheet with excellent deep drawabilityInfo
- Publication number
- JPS5910976B2 JPS5910976B2 JP55032381A JP3238180A JPS5910976B2 JP S5910976 B2 JPS5910976 B2 JP S5910976B2 JP 55032381 A JP55032381 A JP 55032381A JP 3238180 A JP3238180 A JP 3238180A JP S5910976 B2 JPS5910976 B2 JP S5910976B2
- Authority
- JP
- Japan
- Prior art keywords
- rolled steel
- steel sheet
- cold
- deep drawability
- value
- 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
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
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/46—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for sheet metals
- C21D9/48—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for sheet metals deep-drawing sheets
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 Steel (AREA)
- Heat Treatment Of Sheet Steel (AREA)
Description
【発明の詳細な説明】
この発明は良好な深絞り性を有する高張力冷延？板の製
造方法に関する。[Detailed Description of the Invention] Is this invention a high tension cold rolling having good deep drawability? This invention relates to a method of manufacturing a board.
最近自動車、電気製品などの素材として、従来の強度の
低い冷延鋼板に比べて高強度の、つまり高張力冷延鋼板
の利用が盛んになってきた。BACKGROUND ART Recently, high-strength cold-rolled steel sheets, which have higher strength than conventional low-strength cold-rolled steel sheets, have been increasingly used as materials for automobiles, electrical products, and other products.
この目的に合致する高張力冷延鋼板は、従来の冷延鋼板
に劣らないだけのプレス成形性を有することが望ましい
が、一般に強度上昇によって生ずる延性の不足などのた
め、完全にこの条件を満すことは困難である。It is desirable that high-strength cold-rolled steel sheets that meet this purpose have press formability comparable to that of conventional cold-rolled steel sheets, but generally they do not fully meet this condition due to lack of ductility caused by increased strength. It is difficult to do so.
しかしながら、可能なかぎりプレス成形性の向上に努め
なければならない。However, it is necessary to strive to improve press formability as much as possible.
プレス成形性の良否を示す１つの値として、引張試験に
よって求められる塑性歪比ｒがあり、次式に示すｒ値で
絞り性が判定されている。One value that indicates the quality of press formability is the plastic strain ratio r determined by a tensile test, and the drawability is determined by the r value shown in the following equation.
ｒ＝（ ｒｏ ＋２ｒ４５＋ｒｇ ）／４ただし、ｒｏ
：圧延方向のｒ値
ｒ４５：圧延方向に対し４５°方向のｒ値ｒｇ：圧延方
向に対し９０°方向のｒ値
ｒ値が大きい程絞り性は良好である。r=(ro +2r45+rg)/4 However, ro
: r value in the rolling direction r45: r value in the 45° direction to the rolling direction rg: r value in the 90° direction to the rolling direction The larger the r value, the better the drawability.
この発明は、引張強さは一般の冷延鋼板のほぼ３０Ｋ９
／一より高い３５〜４ ５ Ｋｆ／／２ｊで、しかも一
般の冷延鋼板に劣らないｒ値を有する深絞り性を有する
高張力冷延鋼板を提供するものである。This invention has a tensile strength of approximately 30K9 of ordinary cold-rolled steel sheets.
The object of the present invention is to provide a high-strength cold-rolled steel sheet having deep drawability with an r value of 35 to 45 Kf//2j higher than 1, and an r value comparable to that of general cold-rolled steel sheets.
この発明は、Ｃ０．０２〜０．１ ２％Ｓｉ ０．２０
％以下、Ｍｎ ０．１ ０ 〜１．０ ０ ％、Ｐ０．
０２０〜０．１ ０ ０ ％、ｓｏｌ−ＡＩ０．０２０
〜０．１２０％、ＮＯ．００６０〜０．０２００％、残
部はＦｅおよび不可避的元素からなる鋼を連続鋳造又は
造塊分塊圧延にてスラブとなし、Ａｒ３変態点以上の仕
上温度で熱間圧延した後、６００℃以下２５０℃以上で
巻取へ冷間圧延後、３５０〜６００℃の温度域を昇温速
度平均５〜１５０℃／ｈｒ で昇温し、６３０〜７２０
℃の温度域において１〜３０ｈｒ保持し、６００〜３０
０℃の温度域を冷却速度平均６５℃／ｈｒ以下で冷却し
て再結晶・焼なましを施こし、ｒ値の高い、つまり深絞
り性の良好な高張力冷延鋼板を製造する方法である。This invention has C0.02~0.1 2%Si 0.20
% or less, Mn 0.10 to 1.00%, P0.
020-0.100%, sol-AI0.020
~0.120%, NO. 0060 to 0.0200%, the balance being Fe and unavoidable elements. Steel is made into a slab by continuous casting or ingot blooming rolling, and after hot rolling at a finishing temperature of Ar3 transformation point or higher, After cold rolling to coiling at a temperature of 350 to 600 °C, the temperature is raised at an average heating rate of 5 to 150 °C/hr to 630 to 720 °C.
Hold for 1 to 30 hr in the temperature range of ℃, 600 to 30 hr.
A method of producing high-strength cold-rolled steel sheets with a high r value, that is, good deep drawability, by cooling in the 0°C temperature range at an average cooling rate of 65°C/hr or less to perform recrystallization and annealing. be.
この発明において、対象鋼の成分を限定したのは次の理
由による。In this invention, the components of the target steel are limited for the following reasons.
Ｃは０．０２％以下では高強度が得にくく製鋼段階での
脱炭処理が必要となり、又ｏ．１２％を越えると高いｒ
値が得にくいため、深絞り性の向上がみられず、また溶
接性が劣化するため望ましくない。If C is less than 0.02%, it is difficult to obtain high strength and decarburization treatment is required at the steelmaking stage. High r above 12%
Since it is difficult to obtain a value, no improvement in deep drawability is observed, and weldability deteriorates, which is undesirable.
Ｓｉは０．２０％を越えると熱延板の脱スケールが困難
となり、表面疵が発生しやすいと共に冷延後焼鈍工程に
おいてＳｉの酸化による特殊なテンパーカラーが付着し
、゛塗装性などが劣化する。If Si exceeds 0.20%, it becomes difficult to descale the hot-rolled sheet, surface defects are likely to occur, and a special temper color due to oxidation of Si adheres during the annealing process after cold rolling, resulting in deterioration of paintability, etc. do.
Ｍｎは強度増加成分であり、赤熱脆性防止のためにも０
．１０％は必要であるが、１．００％以上になると高い
Ｙ値が得られに《くなり、又コスト面からの問題が生じ
る。Mn is a strength-increasing component and is also added to prevent red heat brittleness.
．． Although 10% is necessary, if it exceeds 1.00%, it becomes difficult to obtain a high Y value, and problems arise in terms of cost.
Ｐは０．０２０％位までは通常の方法で不可避的元素と
して含有せしめるが、′Ｐは鋼の強化に非常に有効であ
ると同時に焼なまし後のＴ値が向上することがよく知ら
れているがＡｌキルド鋼にＰを添加すると、冷延一焼な
まし後の結晶粒はＡｌキルド鋼としては展伸度が小さく
細粒化するため、ｒ値の向上は比較的小さい。Up to about 0.020% of P is contained as an unavoidable element using normal methods, and it is well known that 'P is very effective in strengthening steel and at the same time improves the T value after annealing. However, when P is added to Al-killed steel, the crystal grains after cold rolling and annealing have a small elongation degree and become fine grains for Al-killed steel, so the improvement in r value is relatively small.
しかし、Ｐは鋼を脆化させる成分であり、例えばスポッ
ト溶接部の破壊試験などでナゲット破断をきたし、破断
強度を低下するなどの欠点がある。However, P is a component that embrittles steel, and has drawbacks such as causing nugget fracture during destructive testing of spot welds and reducing fracture strength.
したがって、その含有量は０．１ ０ ０ ％までとす
べきである。Therefore, its content should be up to 0.100%.
ところでこのｐ添加Ａｌキルド鋼について多くの研究を
行った結果、ＮをＰ添加Ａｌキルド鋼冷延鋼板に複合添
加することにより、焼なまし後の結晶粒の展伸度は通常
のＡｌキルド鋼のそれよりもむしろ大きく又、ｒ値も通
常のＡｌキルド鋼と同等以上の値が得られることを明ら
かにした。By the way, as a result of much research on this P-added Al-killed steel, we found that by adding N in combination to P-added Al-killed cold-rolled steel sheets, the degree of elongation of grains after annealing is lower than that of normal Al-killed steel. It was revealed that the r-value was larger than that of the conventional Al-killed steel, and the r-value was equal to or higher than that of ordinary Al-killed steel.
このＮは通常の製鋼方法では０．０ ０ ６ ０％以下
であるが、これを０．０ ２ ０ ０％までの範囲で含
有せしめる。This N is contained in a range up to 0.0200%, although it is 0.0060% or less in a normal steel manufacturing method.
０．０２００％以上の添加では再び結晶粒が微細化され
るので好ましくない。Addition of 0.0200% or more is not preferable because the crystal grains become finer again.
ＡＩは脱酸剤としての役割を有する他、Ｎと結合してＡ
ＩＮを形成し、ｒ値の上昇に寄与する。In addition to acting as a deoxidizing agent, AI combines with N to form A
It forms IN and contributes to increasing the r value.
またＰによる脆化を防止する作用もある。It also has the effect of preventing embrittlement caused by P.
このような効果を奏するには、ｓｏｌ−ＡＩとして、０
．０２０％以上の含有が必要であるが、多量のＡＩ含有
はその作用効果の向上が望めない上、むしろ劣化傾向を
有するのでその上限を０．１ ２ ０％とした。In order to produce such an effect, as sol-AI, 0
．． Although it is necessary to contain AI in an amount of 0.020% or more, the upper limit is set at 0.120% since a large amount of AI cannot be expected to improve its effects and, on the contrary, has a tendency to deteriorate.
またこの発明法において、熱延仕上温度をＡｒ３変態点
以上としたのは、Ａｒ３変態点以下では圧延中にフエラ
イト相が現われ、熱延結晶方位、ひいては冷延成品の結
晶方位が劣化し絞り性の低下をきたすからである。In addition, in this invention method, the hot rolling finishing temperature is set to be higher than the Ar3 transformation point, because below the Ar3 transformation point, a ferrite phase appears during rolling, which deteriorates the hot rolled crystal orientation and, by extension, the crystal orientation of the cold rolled product, resulting in poor drawability. This is because it causes a decrease in
また、熱延巻取温度を６００℃以下２５０℃以上とした
のは、６００℃以上では巻取後にＡＡＮが析出するため
、本来焼鈍昇熱中に析出して成品の絞り性を高める効果
が失われ、２５０℃以下では冷却のための水量を増し能
率の低下を招くが、絞り性に対する効果は変らないから
である。In addition, the reason why the hot rolling coiling temperature was set to 600°C or lower and 250°C or higher is because at 600°C or higher, AAN precipitates after coiling, so the effect of increasing the drawability of the finished product due to precipitation during annealing heating is lost. This is because if the temperature is below 250°C, the amount of water for cooling will increase, leading to a decrease in efficiency, but the effect on squeezing property will not change.
巻取り後は、酸洗等による脱スケールおよび冷間圧延を
行なう。After winding, descaling by pickling or the like and cold rolling are performed.
冷間圧延は一般に行なわれている通常の方法で行なう。Cold rolling is performed by a commonly used method.
冷間圧延後の焼鈍処理において、焼鈍炉での昇温速度を
平均５〜１５０℃／ｈｒ としたのは高いｒ値が得ら
れないからである。In the annealing treatment after cold rolling, the temperature increase rate in the annealing furnace is set to an average of 5 to 150°C/hr because a high r value cannot be obtained.
また、均熱温度を６３０〜７３０℃に限定したのは、６
３０℃以下の温度では再結晶が十分に行なわれず７値の
向上がみられない。In addition, the soaking temperature was limited to 630 to 730°C.
At temperatures below 30° C., recrystallization is not sufficiently performed and no improvement in the 7 value is observed.
一方、７２０℃を越えると鋼板の焼つきなどが起こるた
め好ましくない。On the other hand, if the temperature exceeds 720°C, seizure of the steel plate may occur, which is not preferable.
この温度での保持時間を１〜３０ｈｒと限定したのは、
１ｈｒ未満では再結晶粒の成長が不十分であり、良好な
絞り性が得られないこと、またこれを３０ｈｒ以上延長
しても絞り性向上の効果は少なく、かえって結晶の粗大
化による不具合をきたすからである。The holding time at this temperature was limited to 1 to 30 hours because
If it is less than 1 hr, the growth of recrystallized grains is insufficient and good drawability cannot be obtained, and even if it is extended for more than 30 hr, the effect of improving drawability is small and instead causes problems due to coarsening of the crystals. It is from.
また、冷却速度については、徐冷することによるフエラ
イト相中の固溶炭素の減少効果に基づく時効硬化現象に
よる成品性能の劣化を防止する意味から、平均６５℃／
ｈｒ以下とした。In addition, the cooling rate is set at an average of 65°C /
hr or less.
すなわち、平均冷却速度が６５℃／ｈｒ以上になると時
効劣化が顕著となるからである。That is, when the average cooling rate is 65° C./hr or more, aging deterioration becomes significant.
次に、この発明の実施例について説明する。Next, embodiments of the invention will be described.
実施例
第１表に示す成分を有する鋼を転炉で溶製し、連続鋳造
によりスラブとし、これらのスラブを仕上温度８８０℃
で熱間圧延して２．８ｒｒｒｒｒＬ厚さの鋼板とし、こ
れを酸洗後冷間圧延して０．７ｍｍ厚さの冷延鋼板とし
た。Example Steel having the components shown in Table 1 is melted in a converter and made into slabs by continuous casting, and these slabs are heated to a finishing temperature of 880°C.
The steel plate was hot-rolled to obtain a steel plate having a thickness of 2.8 mm, which was pickled and then cold-rolled to obtain a cold-rolled steel plate having a thickness of 0.7 mm.
その後、第１表に示す温度で１７時間焼なましを施した
。Thereafter, annealing was performed for 17 hours at the temperatures shown in Table 1.
そして得られた鋼板の機械的性質について試験を行った
結果を第２表に示す。Table 2 shows the results of tests on the mechanical properties of the obtained steel sheets.
第２表の結果より、本発明の実施による鋼はすべて３
６ Ｋｌ’ｍｍ以上の引張強さが得られ、また引張強さ
が３６Ｋ９７一以上でありながらＴ値もすべて１．８以
上と、すぐれた深絞り性を保持していることがわかる。From the results in Table 2, it can be seen that all steels according to the present invention have a
A tensile strength of 6 Kl'mm or more was obtained, and while the tensile strength was 36K97 or more, all T values were 1.8 or more, indicating that excellent deep drawability was maintained.
このようなこの発明鋼の特性はＰおよびＮの複合含有と
高温再結晶焼なまし効果によるものである。Such characteristics of the steel of the present invention are due to the combined content of P and N and the effect of high temperature recrystallization annealing.
Claims (1)
Ｍｎ０．１０〜１．００係、０．０２０〜０．１００％
、ｓｏｔ−Ａｔ０．２０〜０．１２０％、ＮＯ．００６
０〜０．０ ２ ０ ０％、残部はＦｅおよび不可避的
元素からなる鋼を連続鋳造又は造塊分塊にてスラブとな
し、Ａｒ３ 変態点以上の仕上温度で熱間圧延した後、
６００℃以下２５０℃以上で巻取り、冷間圧延後、３５
０〜６００℃の温度域を昇温速度平均５〜１５０℃／ｈ
ｒで昇温し、６３０〜７２０℃の温度域において１〜３
０ｈｒ保持し、６００〜３００℃の温度域を冷却速度平
均６５℃／ｈｒ以下で冷却して再結晶焼なましを施すこ
とを特徴とする深絞り性のすぐれた高張力冷延鋼板の製
造方法。IC 0.02-0.12, Sin, 20% or less,
Mn 0.10-1.00, 0.020-0.100%
, sot-At0.20-0.120%, NO. 006
Steel consisting of 0 to 0.0200%, the balance being Fe and unavoidable elements is made into a slab by continuous casting or ingot blooming, and after hot rolling at a finishing temperature of Ar3 transformation point or higher,
After winding and cold rolling at 600℃ or lower and 250℃ or higher, 35
Temperature range from 0 to 600℃, heating rate average 5 to 150℃/h
1 to 3 in the temperature range of 630 to 720°C.
A method for manufacturing a high-strength cold-rolled steel sheet with excellent deep drawability, characterized by performing recrystallization annealing by holding the steel sheet for 0 hr and cooling in a temperature range of 600 to 300°C at an average cooling rate of 65°C/hr or less. .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP55032381A JPS5910976B2 (en) | 1980-03-13 | 1980-03-13 | Method for manufacturing high-strength cold-rolled steel sheet with excellent deep drawability |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP55032381A JPS5910976B2 (en) | 1980-03-13 | 1980-03-13 | Method for manufacturing high-strength cold-rolled steel sheet with excellent deep drawability |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS56130429A JPS56130429A (en) | 1981-10-13 |
| JPS5910976B2 true JPS5910976B2 (en) | 1984-03-13 |
Family
ID=12357365
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP55032381A Expired JPS5910976B2 (en) | 1980-03-13 | 1980-03-13 | Method for manufacturing high-strength cold-rolled steel sheet with excellent deep drawability |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5910976B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61166992A (en) * | 1985-01-17 | 1986-07-28 | Sumitomo Metal Ind Ltd | Electric galvanizing method |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5331132A (en) * | 1976-09-03 | 1978-03-24 | Konishiroku Photo Ind Co Ltd | Silver halide color photographic light sensitive material |
| JPS5531182A (en) * | 1978-08-28 | 1980-03-05 | Sumitomo Metal Ind Ltd | High strength cold rolled steel plate with superior workability and manufacture thereof |
-
1980
- 1980-03-13 JP JP55032381A patent/JPS5910976B2/en not_active Expired
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5331132A (en) * | 1976-09-03 | 1978-03-24 | Konishiroku Photo Ind Co Ltd | Silver halide color photographic light sensitive material |
| JPS5531182A (en) * | 1978-08-28 | 1980-03-05 | Sumitomo Metal Ind Ltd | High strength cold rolled steel plate with superior workability and manufacture thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS56130429A (en) | 1981-10-13 |
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