JPH0826411B2 - 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
- JPH0826411B2 JPH0826411B2 JP3357508A JP35750891A JPH0826411B2 JP H0826411 B2 JPH0826411 B2 JP H0826411B2 JP 3357508 A JP3357508 A JP 3357508A JP 35750891 A JP35750891 A JP 35750891A JP H0826411 B2 JPH0826411 B2 JP H0826411B2
- Authority
- JP
- Japan
- Prior art keywords
- steel sheet
- deep drawability
- rolled steel
- less
- rolling
- 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 - Fee Related
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/001—Ferrous alloys, e.g. steel alloys containing N
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/004—Very low carbon steels, i.e. having a carbon content of less than 0,01%
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/12—Ferrous alloys, e.g. steel alloys containing tungsten, tantalum, molybdenum, vanadium, or niobium
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/14—Ferrous alloys, e.g. steel alloys containing titanium or zirconium
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Heat Treatment Of Steel (AREA)
- Heat Treatment Of Sheet Steel (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は深絞り性の優れた高強度
冷延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 having excellent deep drawability.
【０００２】[0002]
【従来の技術及び発明が解決しようとする課題】特に、
近年では自動車の安全性、車体重量軽減(燃費向上)の問
題から、従来軟鋼板が使用された部品にまで高強度鋼板
の利用が拡大されつつある。PRIOR ART AND PROBLEMS TO BE SOLVED BY THE INVENTION In particular,
In recent years, the use of high-strength steel sheets has been expanding to parts where mild steel sheets have been conventionally used due to the problems of automobile safety and vehicle body weight reduction (improvement in fuel consumption).
【０００３】従来より、深絞り性の優れた冷延鋼板を得
るために極低炭素鋼にＴiやＮbなどの強力な炭窒化物形
成元素を添加する方法が知られている。特に軟鋼板の分
野にて深絞り性を要求される用途の大部分に、この極低
炭素鋼が適用され始めている。しかし、引張強度３８kg
f／mm2級以上の高強度鋼板では、強度が高くなるにつれ
て他の合金元素が多量に添加されるため、上記の極低炭
素鋼であっても、通常、深絞り性は劣化する。Conventionally, there has been known a method of adding a strong carbonitride-forming element such as Ti or Nb to an ultra-low carbon steel in order to obtain a cold-rolled steel sheet having an excellent deep drawability. In particular, in the field of mild steel sheets, this ultra low carbon steel has begun to be applied to most of the applications that require deep drawability. However, tensile strength 38kg
In high-strength steel sheets of f / mm 2 grade or higher, other alloying elements are added in large amounts as the strength increases, so that even the above-mentioned ultra-low carbon steels usually have poor deep drawability.
【０００４】ＴiやＮbを添加した極低炭素鋼の深絞り性
向上及びコイル内の材質均一性向上を目的として、特開
昭６１−２７６９２７号、特開平１−１９１７４８号な
どが提案されている。これらは、特に熱延条件の仕上温
度〜巻取りまでの冷却速度を速くすることにより、フェ
ライト結晶粒の細粒化や転位の導入による析出促進によ
り上記効果が得られるとしている。通常、熱延鋼板にて
フェライト結晶粒が細かいほど、またＴi、Ｎbの炭窒化
物が充分析出しているほど、冷延鋼板の深絞り性は向上
することが知られている。しかし、これらの技術には、
引張強度４３kgf／mm2以下の材質特性が示されているに
すぎず、４０kgf／mm2以上、特に４５kgf／mm2以上の高
強度鋼板についての材質特性は不明である。JP-A-61-276927, JP-A-1-191748 and the like have been proposed for the purpose of improving the deep drawability of ultra-low carbon steel containing Ti and Nb and improving the uniformity of the material in the coil. . It is said that the above effects can be obtained by increasing the cooling rate from the finishing temperature of the hot rolling condition to the winding, in particular, by refining the ferrite crystal grains and promoting precipitation by introducing dislocations. It is generally known that the finer the ferrite crystal grains in the hot rolled steel sheet and the more the carbonitrides of Ti and Nb are deposited, the better the deep drawability of the cold rolled steel sheet. However, these technologies include
Only tensile strength 43kgf / mm 2 or less of material properties are shown, 40 kgf / mm 2 or more, the material characteristics are unknown in particular 45 kgf / mm 2 or more high-strength steel sheet.
【０００５】このように、自動車の安全性や、鋼板の高
強度化による板厚減少で車体重量の軽減とそれに伴う燃
費向上が求められている事情のもとで、未だこれらを十
分に満たし得る深絞り性の優れた高強度鋼板材料が得ら
れていないのが現状である。As described above, under the circumstances where the safety of automobiles and the reduction of the vehicle body weight due to the reduction of the plate thickness due to the strengthening of the steel sheet and the accompanying improvement of the fuel consumption are required, these can still be sufficiently satisfied. At present, no high-strength steel sheet material with excellent deep drawability has been obtained.
【０００６】本発明は、上述の要請に応えるべくなされ
たものであって、高強度化しても優れた深絞り性を確保
できる冷延鋼板の製造方法を提供することを目的とする
ものである。The present invention has been made in order to meet the above-mentioned demands, and an object of the present invention is to provide a method for manufacturing a cold-rolled steel sheet capable of ensuring excellent deep drawability even when the strength is increased. .
【０００７】[0007]
【課題を解決するための手段】前記課題を解決するた
め、本発明者等は、極低炭素鋼にて４０kgf／mm2以上の
高強度と共に優れた深絞り性が確保するべく、ＴiやＮb
を添加した極低炭素鋼の成分組成、熱延条件、冷延条
件、連続焼鈍条件、組織等々について総合的に研究を重
ねた結果、ここに本発明を完成したものである。In order to solve the above-mentioned problems, the inventors of the present invention have made Ti and Nb in order to secure a high strength of 40 kgf / mm 2 or more and an excellent deep drawability with ultra-low carbon steel.
The present invention has been completed as a result of comprehensive research on the component composition, hot rolling conditions, cold rolling conditions, continuous annealing conditions, microstructures, etc. of the ultra-low carbon steel with addition of.
【０００８】すなわち、本発明は、Ｃ:０.００５％以
下、Ｓi:１.０％以下、Ｍn:０.６〜２.５％、Ｐ:０.０
５〜０.１５％、Ｓ:０.０１０％以下、Ａl:０.００５〜
０.１０％、Ｎ:０.００３５％以下を含有し、Ｔi:０.０
１０〜０.１０％及びＮb:０.００５〜０.０３％の１種
又は２種を含有し、更にＢ:０.０００４〜０.００２０
％を含有し、残部がＦe及び不可避的不純物からなる鋼
を熱間圧延するに際し、仕上温度９３０℃以上で仕上圧
延を終了した後、直ちに巻取りまでの平均冷却速度を５
０〜２００℃／secにて冷却し、６００℃以下にて巻取
ることにより、アシキュラーフェライト又はベイナイト
のいずれか一方又は両方からなる組織を得、次いで該熱
延鋼板を酸洗後、圧下率５０％以上にて冷間圧延を行
い、再結晶温度〜Ａc3点にて連続焼鈍を行うことを特徴
とする深絞り性に優れた高強度冷延鋼板の製造方法を要
旨とするものである。That is, according to the present invention, C: 0.005% or less, Si: 1.0% or less, Mn: 0.6 to 2.5%, P: 0.0
5 to 0.15%, S: 0.010% or less, Al: 0.005
Containing 0.10%, N: 0.0035% or less, Ti: 0.0
10% to 0.10% and Nb: 0.005 to 0.03% of 1 or 2 types, and further B: 0.0004 to 0.0020%.
%, With the balance being Fe and inevitable impurities, during hot rolling, after finishing rolling at a finishing temperature of 930 ° C. or higher, immediately after cooling, the average cooling rate until winding is 5
By cooling at 0 to 200 ° C./sec and winding at 600 ° C. or less, a structure consisting of either or both of acicular ferrite and bainite is obtained, and then the hot rolled steel sheet is pickled and then the rolling reduction is obtained. The gist is a method for producing a high-strength cold-rolled steel sheet excellent in deep drawability, which comprises cold rolling at 50% or more and continuous annealing at a recrystallization temperature to Ac 3 point. .
【０００９】以下に本発明を更に詳述する。The present invention will be described in more detail below.
【００１０】[0010]
【００１１】まず、本発明における化学成分の限定理由
について説明する。First, the reasons for limiting the chemical components in the present invention will be explained.
【００１２】Ｃ：深絞り性(特に高ｒ値化)の向上のため
にＣ量は低い程好ましく、０.００５％以下とする。特
に０.００３０％以下が望ましい。しかし、０.００５％
を超えると、後述のＴiやＮbが添加されていても、伸び
が劣化する。C: In order to improve the deep drawability (particularly high r-value), the lower the amount of C, the more preferable, and the content is 0.005% or less. Particularly, 0.0030% or less is desirable. However, 0.005%
If it exceeds, even if Ti or Nb described later is added, the elongation deteriorates.
【００１３】Ｓi：Ｓiは伸びを損わずに高強度化を図る
ために必要な元素である。目的とする強度レベルに応じ
て添加されるが、１.０％を超えると塗装性、化成処理
性を損なうばかりか、溶融めっきを施す場合、不めっき
を生じ易くなるため、Ｓi量は１.０％以下とする。Si: Si is an element necessary for achieving high strength without impairing elongation. It is added depending on the intended strength level, but if it exceeds 1.0%, not only the paintability and chemical conversion treatability are impaired, but also non-plating tends to occur during hot dipping, so the Si content is 1. It is 0% or less.
【００１４】Ｍn：Ｍnは本発明における重要な元素の１
つである。通常、Ｓiと同様の目的で添加されるが、本
発明においては、後述のように、熱延鋼板の組織をポリ
コナルフェライトを含まずアシュキラーフェライト又は
ベイナイトの一方若しくは両方にするために必要な元素
である。これはＭnによる焼入性向上によるためであ
り、０.６％未満では後述の如く巻取まで所定の冷却速
度にしても、上記組織が困難となる。しかし、過度の添
加は延性(伸び)やスポット溶接性などを損なうため、上
限を２.５％とする。Mn: Mn is one of the important elements in the present invention.
One. Usually, it is added for the same purpose as Si, but in the present invention, as described later, it is necessary to make the structure of the hot-rolled steel sheet one or both of Ashkiller ferrite or bainite without containing polyconal ferrite. It is an element. This is because the hardenability is improved by Mn, and if it is less than 0.6%, the above structure becomes difficult even at a predetermined cooling rate until winding as described later. However, excessive addition impairs ductility (elongation) and spot weldability, so the upper limit is made 2.5%.
【００１５】Ｐ：Ｐは深絞り性を損なわずに高強度化を
図るために積極的に添加する。引張強さ３７０Ｎ／mm2
以上を得るには０.０５％以上を必要とするが、過度の
添加は成形後の二次加工脆性を生じ易くするため、０.
１５％を上限とする。好ましくは０.０５〜０.１０％で
ある。P: P is positively added in order to increase the strength without impairing the deep drawability. Tensile strength 370N / mm 2
To obtain the above, 0.05% or more is required, but since excessive addition easily causes secondary processing brittleness after molding, it is 0.0
The upper limit is 15%. It is preferably 0.05 to 0.10%.
【００１６】Ｓ：ＳはＴiＳ、ＭnＳとして析出し、鋼の
延性を劣化させるため、少ないほど望ましく、０.０１
０％以下、好ましくは０.００５％以下に抑える。S: S precipitates as TiS and MnS and deteriorates the ductility of steel. Therefore, the smaller the content, the better.
It is suppressed to 0% or less, preferably 0.005% or less.
【００１７】Ａl：Ａlは脱酸剤として添加され、０.０
０５％以上でないとその効果が得られない。一方、過度
の添加は介在物の量を増し、成形性を損なうため、上限
を０.１０％とする。Al: Al is added as a deoxidizer and is added to 0.0
If it is not more than 05%, the effect cannot be obtained. On the other hand, excessive addition increases the amount of inclusions and impairs formability, so the upper limit is made 0.10%.
【００１８】Ｎ：Ｎは熱間圧延前にＴiによって析出固
定されているため、Ｎそのものによる深絞り性、延性へ
の影響は小さい。しかし、多すぎると析出物量が増し、
延性が劣化すること、及びＮを固定するに必要なＴi量
が増しコスト高となるため、０.００３５％以下とす
る。好ましくは０.００２５％以下である。N: N is precipitated and fixed by Ti before hot rolling, so that N itself has little influence on deep drawability and ductility. However, if too much, the amount of precipitates increases,
Since the ductility deteriorates and the amount of Ti required to fix N increases and the cost increases, it is set to 0.0035% or less. It is preferably 0.0025% or less.
【００１９】以上の元素の他に、本発明では深絞り性確
保のためにＴi、Ｎbの１種又は２種を所定量添加する。In addition to the above elements, in the present invention, one or two kinds of Ti and Nb are added in a predetermined amount in order to secure deep drawability.
【００２０】すなわち、Ｔiは鋼中のＮやＣの大部分を
ＴiＮ、ＴiＣとして、一方、ＮbはＮbＣとして、いずれ
も熱延段階にて析出し、冷延と焼鈍後の深絞り性を向上
させる。しかし、Ｔi量が０.０１０未満、Ｎb量が０.０
０５％未満ではＣの大部分が固溶状態として残り、深絞
り性が劣化する。一方、Ｔi量が０.１０％、Ｎb量が０.
０３％をそれぞれ超えると上記効果が飽和するばかり
か、コスト高を招く。That is, Ti is mostly N and C in steel as TiN and TiC, while Nb is NbC, both of which are precipitated in the hot rolling stage to improve the deep drawability after cold rolling and annealing. Let However, Ti content is less than 0.010, Nb content is 0.0
If it is less than 05%, most of C remains in a solid solution state and the deep drawability deteriorates. On the other hand, the Ti content is 0.10% and the Nb content is 0.10%.
If it exceeds 03%, not only the above effect is saturated, but also the cost is increased.
【００２１】Ｂ：Ｂも本発明における重要な元素の１つ
であり、熱延鋼板での組織をアシキュラーフェライト又
はベイナイトの一方若しくは両方にするためと、成形後
の２次加工脆性を改善するために必要である。これらの
効果を発揮させるためには０.０００４％以上を必要と
するが、０.００２０％を超えると効果が飽和するた
め、Ｂ量は０.０００４〜０.００２０％の範囲とする。B: B is also one of the important elements in the present invention, and is for making the structure of the hot rolled steel sheet one or both of acicular ferrite and bainite, and improving the secondary work brittleness after forming. Is necessary for. In order to exert these effects, 0.0004% or more is required, but when the amount exceeds 0.0020%, the effect is saturated, so the amount of B is set in the range of 0.0004 to 0.0020%.
【００２２】次に本発明における熱間圧延、冷間圧延、
連続焼鈍の各条件の限定理由について説明する。Next, in the present invention, hot rolling, cold rolling,
The reasons for limiting each condition of continuous annealing will be described.
【００２３】上記化学成分を有する鋼について常法にて
加熱されたスラブは、仕上温度９３０℃以上にて仕上げ
られ、その後、巻取りまでの平均冷却速度を５０〜２０
０℃／secにて冷却し、コイルに巻取られる。The slab heated by the usual method for the steel having the above chemical composition is finished at a finishing temperature of 930 ° C. or higher, and then the average cooling rate until winding is 50 to 20.
It is cooled at 0 ° C / sec and wound on a coil.
【００２４】深絞り性の代表的特性であるｒ値と仕上温
度及び巻取りまでの冷却速度との関係について、詳細に
調べた結果を図１に示す。これより、巻取りまでの冷却
速度が速いと仕上温度によらず、より高いｒ値を示し、
特に仕上温度が９３０℃以上にて効果が顕著となり、
１.８以上の高ｒ値が得られる。FIG. 1 shows the results of a detailed examination of the relationship between the r value, which is a typical characteristic of deep drawability, the finishing temperature and the cooling rate until winding. From this, if the cooling rate until winding is fast, it shows a higher r value regardless of the finishing temperature,
Especially when the finishing temperature is 930 ° C or higher, the effect becomes remarkable,
A high r value of 1.8 or more is obtained.
【００２５】このように仕上温度が高く、しかも巻取り
までの冷却速度が速いほど深絞り性が向上する明確な理
由は現状では明らかではないが、熱延鋼板での組織がポ
リゴナルフェライトを含まずアシュキラーフェライト又
はベイナイトの一方或いは両方が混在した組織となって
おり、これらの組織は非常に微細なために冷延、焼鈍後
の深絞り性が向上したためと考えられる。また、仕上温
度がＡr3点以上でも、高温ほど熱延直後のオーステナイ
ト粒は大きく、このために上記組織になり易いものと考
えられる。しかし、仕上温度が９３０℃未満ではポリゴ
ナルフェライトが生成し易くなり、低温ほどアシュキュ
ラーフェライト組織の割合が減少するため、高ｒ値が得
にくくなる。Although the clear reason why the deep drawability is improved as the finishing temperature is higher and the cooling rate before winding is higher is not clear at present, the structure of the hot rolled steel sheet contains polygonal ferrite. However, it is considered that one or both of Ashkiller ferrite and bainite are mixed, and these structures are so fine that the deep drawability after cold rolling and annealing is improved. Further, even if the finishing temperature is at or above the Ar 3 point, the higher the temperature, the larger the austenite grains immediately after hot rolling, and it is considered that the above structure is likely to occur. However, when the finishing temperature is lower than 930 ° C., polygonal ferrite is likely to be generated, and the lower the temperature is, the smaller the proportion of the ashular ferrite structure is, so that it becomes difficult to obtain a high r value.
【００２６】一方、巻取りまでの冷却速度も上記所望組
織を得るために必要であり、５０℃／sec未満ではやは
り所望組織の割合が減少し、深絞り性が得られない。ま
た、冷却速度があまりに速いと、鋼板の形状性が悪くな
り、製品の歩留りや生産性が低下するため、上限を２０
０℃／secとする。On the other hand, the cooling rate up to winding is also necessary to obtain the desired structure, and if it is less than 50 ° C./sec, the ratio of the desired structure is also reduced and the deep drawability cannot be obtained. On the other hand, if the cooling rate is too fast, the formability of the steel sheet deteriorates, and the product yield and productivity decrease, so the upper limit is set to 20.
0 ° C./sec.
【００２７】冷却後の巻取温度は、６００℃より高い温
度以上ではＴiとＰの析出物が生成し易くなり、このた
めにＣと結合するＴi量が減少するため、熱延鋼板での
固溶Ｃ量が増し、高ｒ値が得られない。When the coiling temperature after cooling is higher than 600 ° C., precipitates of Ti and P tend to be formed, and the amount of Ti bound to C is reduced, so that the solidification in the hot-rolled steel sheet is reduced. The amount of dissolved C increases and a high r value cannot be obtained.
【００２８】次いで、熱延鋼板は常法により酸洗した
後、冷間圧延率５０％以上にて冷延鋼板とする。冷延率
が５０％未満では所望とする高ｒ値が得られない。Next, the hot-rolled steel sheet is pickled by a conventional method and then made into a cold-rolled steel sheet at a cold rolling rate of 50% or more. If the cold rolling rate is less than 50%, the desired high r value cannot be obtained.
【００２９】その後、連続焼鈍を行うが、焼鈍温度は再
結晶温度以上、Ａc3点以下とする。再結晶温度未満では
加工組織が残存し、一方、Ａc3点より高いと焼鈍後の組
織がアシキュラーフェライトとなり易いため、いずれも
深絞り性の劣化を招く。好ましくは７５０〜９３０℃の
範囲である。After that, continuous annealing is performed, but the annealing temperature is set to the recrystallization temperature or higher and the Ac 3 point or lower. If the temperature is lower than the recrystallization temperature, the worked structure remains, while if it is higher than the Ac 3 point, the structure after annealing is likely to become acicular ferrite, which causes deterioration of deep drawability. It is preferably in the range of 750 to 930 ° C.
【００３０】連続焼鈍にて冷却後は、必要に応じて過時
効処理を施してもよい。また、本発明鋼は合金化溶融め
っき、電気めっきなど表面処理鋼板の原板として用いて
も何ら問題はない。また焼鈍後の冷延鋼板について形状
修正などのために軽度の調質圧延を施してもよい。After cooling by continuous annealing, an overaging treatment may be carried out if necessary. Further, the steel of the present invention can be used as an original plate of a surface-treated steel plate such as alloying hot dipping and electroplating without any problem. The cold-rolled steel sheet after annealing may be lightly temper-rolled in order to correct the shape.
【００３１】次に本発明の実施例を示す。Next, examples of the present invention will be described.
【００３２】[0032]
【実施例】実験室溶解にて得られたExample: Obtained by laboratory dissolution
【表１】 に示す各種成分組成の鋼を３０mm厚のスラブとした後、
実験に供した。すなわち、これを通常の温度で加熱後、[Table 1] After making the steel of various composition shown in slab 30mm thick,
It was subjected to an experiment. That is, after heating it at a normal temperature,
【表２】 に示す熱間圧延条件にて３.２mm厚に仕上げた後、巻取
り、表２中の条件で冷間圧延と１mm焼鈍条件(均熱時間
１分)を行い、更に０.８％の調質圧延を施した。なお、
鋼Ｎo.４Ｄについては、３.２mm厚の熱延鋼板を１.７mm
厚に表裏面研削した後、冷間圧延、焼鈍、調質圧延を施
した。引張特性及び深絞り性を表２に併記する。[Table 2] After finishing to a thickness of 3.2 mm under the hot rolling conditions shown in Fig. 1, the product was wound up, cold rolled under the conditions shown in Table 2 and annealed under 1 mm conditions (soaking time 1 minute), and further adjusted to 0.8%. Quality rolling was performed. In addition,
For Steel No. 4D, 3.2 mm hot rolled steel sheet is 1.7 mm
After the front and back surfaces were thickly ground, cold rolling, annealing and temper rolling were performed. The tensile properties and deep drawability are also shown in Table 2.
【００３３】本発明例で得られた鋼板は、いずれも、熱
延鋼板にてアシュキラーフェライト若しくはベイナイト
の一方又はこれらが混在した組織であり、焼鈍後のＴＳ
が４０kgf／mm2以上にて高ｒ値を有する深絞り性に優れ
た鋼板である。Each of the steel sheets obtained in the examples of the present invention is a hot-rolled steel sheet having one of Ashkiller ferrite and bainite, or a structure in which these are mixed, and TS after annealing is obtained.
Is a steel sheet having a high r value of 40 kgf / mm 2 or more and excellent in deep drawability.
【００３４】これらに比べて、化学成分が本発明範囲外
である比較例Ｎo.８〜Ｎo.１８で得られた鋼板にあって
は、Ｎo.８〜Ｎo.１６及びＮo.１８は熱延板組織が所望
の組織であるが、焼鈍後のＴＳ、Ｅl、ｒ値のいずれか
が低い。また、Ｎo.１７は熱延板組織にポリゴナルフェ
ライトが生成しており、所望の組織でないため、ｒ値が
低い。In comparison with these, in the steel sheets obtained in Comparative Examples No. 8 to No. 18 whose chemical components are out of the range of the present invention, No. 8 to No. 16 and No. 18 are hot rolled. Although the plate structure is a desired structure, any of TS, El, and r value after annealing is low. Further, No. 17 has a low r value because polygonal ferrite is formed in the structure of the hot rolled sheet and is not a desired structure.
【００３５】次に、本発明範囲内の成分組成の鋼(４Ａ
〜４Ｅ)について、表２に示すようにいずれかの製造条
件を本発明範囲外の条件にて製造した鋼板では、いずれ
もｒ値が低く、深絞り性に劣ることが明らかである。Next, a steel having a composition within the scope of the present invention (4A
4E), as shown in Table 2, it is clear that any steel sheet manufactured under any of the manufacturing conditions outside the scope of the present invention has a low r value and is inferior in deep drawability.
【００３６】[0036]
【発明の効果】以上詳述したように、本発明によれば、
引張強さ４０kgf／mm2以上、特に４５kgf／mm2以上の高
強度冷延鋼板において、従来より深絞り性を著しく向上
させることができる。また、この冷延鋼板は合金化溶融
Ｚnめっき、電気めっきなどの表面処理を施しても何ら
支障のないことから、表面処理鋼板としても使用でき、
その産業上の効果は大きい。As described in detail above, according to the present invention,
Tensile strength of 40 kgf / mm 2 or more, particularly in the 45 kgf / mm 2 or more high-strength cold-rolled steel sheet, it is possible to significantly improve the conventionally deep drawability. Further, this cold-rolled steel sheet can be used as a surface-treated steel sheet since it does not cause any trouble even if it is subjected to surface treatment such as alloying hot-dip Zn plating and electroplating.
Its industrial effect is great.
【図１】本発明範囲内の化学成分を有する鋼におけるｒ
値と仕上温度及び巻取りまでの平均冷却速度との関係を
示した図である。FIG. 1 r in steel with chemical composition within the scope of the invention
It is the figure which showed the relationship between the value, the finishing temperature, and the average cooling rate until winding.
Claims (1)
以下、Ｓi:１.０％以下、Ｍn:０.６〜２.５％、Ｐ:０.
０５〜０.１５％、Ｓ:０.０１０％以下、Ａl:０.００５
〜０.１０％、Ｎ:０.００３５％以下を含有し、Ｔi:０.
０１０〜０.１０％及びＮb:０.００５〜０.０３％の１
種又は２種を含有し、更にＢ:０.０００４〜０.００２
０％を含有し、残部がＦe及び不可避的不純物からなる
鋼を熱間圧延するに際し、仕上温度９３０℃以上で仕上
圧延を終了した後、直ちに巻取りまでの平均冷却速度を
５０〜２００℃／secにて冷却し、６００℃以下にて巻
取ることにより、アシキュラーフェライト又はベイナイ
トのいずれか一方又は両方からなる組織を得、次いで該
熱延鋼板を酸洗後、圧下率５０％以上にて冷間圧延を行
い、再結晶温度〜Ａc3点にて連続焼鈍を行うことを特徴
とする深絞り性に優れた高強度冷延鋼板の製造方法。1. By weight% (hereinafter the same), C: 0.005%
Below, Si: 1.0% or less, Mn: 0.6 to 2.5%, P: 0.0.
05-0.15%, S: 0.010% or less, Al: 0.005
.About.0.10%, N: 0.0035% or less, Ti: 0.0.
010 to 0.10% and Nb: 0.005 to 0.03% of 1
Or two kinds, and further B: 0.0004 to 0.002
When hot rolling a steel containing 0% and the balance Fe and unavoidable impurities, after finishing rolling at a finishing temperature of 930 ° C. or higher, immediately after cooling, the average cooling rate until winding is 50 to 200 ° C. / By cooling at 600 sec or less and winding at 600 ° C. or lower, a structure consisting of either or both of acicular ferrite and bainite is obtained, and then the hot rolled steel sheet is pickled and then the rolling reduction is 50% or more. A method for producing a high-strength cold-rolled steel sheet excellent in deep drawability, which comprises performing cold rolling and continuous annealing at a recrystallization temperature to an Ac 3 point.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3357508A JPH0826411B2 (en) | 1991-12-25 | 1991-12-25 | Method for manufacturing high strength cold rolled steel sheet with excellent deep drawability |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3357508A JPH0826411B2 (en) | 1991-12-25 | 1991-12-25 | Method for manufacturing high strength cold rolled steel sheet with excellent deep drawability |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH05171293A JPH05171293A (en) | 1993-07-09 |
| JPH0826411B2 true JPH0826411B2 (en) | 1996-03-13 |
Family
ID=18454485
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3357508A Expired - Fee Related JPH0826411B2 (en) | 1991-12-25 | 1991-12-25 | Method for manufacturing high strength cold rolled steel sheet with excellent deep drawability |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0826411B2 (en) |
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|---|---|---|---|---|
| US9999918B2 (en) | 2005-10-20 | 2018-06-19 | Nucor Corporation | Thin cast strip product with microalloy additions, and method for making the same |
| US9149868B2 (en) | 2005-10-20 | 2015-10-06 | Nucor Corporation | Thin cast strip product with microalloy additions, and method for making the same |
| EP2162252B1 (en) * | 2007-05-06 | 2021-07-07 | Nucor Corporation | An age hardened thin cast strip product with microalloy additions, and method for making the same |
| US20100215981A1 (en) * | 2009-02-20 | 2010-08-26 | Nucor Corporation | Hot rolled thin cast strip product and method for making the same |
| JP5447564B2 (en) * | 2012-03-16 | 2014-03-19 | 新日鐵住金株式会社 | Cold rolled steel sheet manufacturing method |
| JP5716760B2 (en) * | 2013-01-10 | 2015-05-13 | 新日鐵住金株式会社 | Cold rolled steel sheet manufacturing method |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59126719A (en) * | 1983-01-11 | 1984-07-21 | Nippon Steel Corp | Production of high tension hot rolled steel sheet having excellent processability |
| JPH02163318A (en) * | 1988-12-15 | 1990-06-22 | Nisshin Steel Co Ltd | Production of high-tension cold rolled steel sheet having excellent press formability |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6417731A (en) * | 1987-07-10 | 1989-01-20 | Canon Kk | Paper feeder |
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1991
- 1991-12-25 JP JP3357508A patent/JPH0826411B2/en not_active Expired - Fee Related
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59126719A (en) * | 1983-01-11 | 1984-07-21 | Nippon Steel Corp | Production of high tension hot rolled steel sheet having excellent processability |
| JPH02163318A (en) * | 1988-12-15 | 1990-06-22 | Nisshin Steel Co Ltd | Production of high-tension cold rolled steel sheet having excellent press formability |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH05171293A (en) | 1993-07-09 |
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