JPH01188630A - Manufacture of cold rolled steel sheet having superior press formability - Google Patents
Manufacture of cold rolled steel sheet having superior press formabilityInfo
- Publication number
- JPH01188630A JPH01188630A JP1009088A JP1009088A JPH01188630A JP H01188630 A JPH01188630 A JP H01188630A JP 1009088 A JP1009088 A JP 1009088A JP 1009088 A JP1009088 A JP 1009088A JP H01188630 A JPH01188630 A JP H01188630A
- Authority
- JP
- Japan
- Prior art keywords
- less
- steel sheet
- temperature
- rolling
- cooling
- 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.)
- Pending
Links
- 239000010960 cold rolled steel Substances 0.000 title claims abstract description 18
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 9
- 238000001816 cooling Methods 0.000 claims abstract description 48
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 27
- 239000010959 steel Substances 0.000 claims abstract description 27
- 238000000137 annealing Methods 0.000 claims abstract description 26
- 238000005096 rolling process Methods 0.000 claims abstract description 20
- 238000005098 hot rolling Methods 0.000 claims abstract description 15
- 238000005097 cold rolling Methods 0.000 claims abstract description 12
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 7
- 238000004804 winding Methods 0.000 claims description 10
- 238000007796 conventional method Methods 0.000 claims description 5
- 239000012535 impurity Substances 0.000 claims description 4
- 229910052757 nitrogen Inorganic materials 0.000 abstract description 3
- 229910052698 phosphorus Inorganic materials 0.000 abstract 1
- 238000000034 method Methods 0.000 description 12
- 150000001247 metal acetylides Chemical class 0.000 description 8
- 238000001556 precipitation Methods 0.000 description 8
- 230000000694 effects Effects 0.000 description 6
- 238000007747 plating Methods 0.000 description 5
- 230000001771 impaired effect Effects 0.000 description 4
- 238000005554 pickling Methods 0.000 description 4
- 239000002244 precipitate Substances 0.000 description 4
- 239000013078 crystal Substances 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 239000000047 product Substances 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- 238000009749 continuous casting Methods 0.000 description 2
- 238000005246 galvanizing Methods 0.000 description 2
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- 229910001335 Galvanized steel Inorganic materials 0.000 description 1
- 229910001209 Low-carbon steel Inorganic materials 0.000 description 1
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 description 1
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 1
- 230000003679 aging effect Effects 0.000 description 1
- 238000009529 body temperature measurement Methods 0.000 description 1
- CUZMQPZYCDIHQL-VCTVXEGHSA-L calcium;(2s)-1-[(2s)-3-[(2r)-2-(cyclohexanecarbonylamino)propanoyl]sulfanyl-2-methylpropanoyl]pyrrolidine-2-carboxylate Chemical compound [Ca+2].N([C@H](C)C(=O)SC[C@@H](C)C(=O)N1[C@@H](CCC1)C([O-])=O)C(=O)C1CCCCC1.N([C@H](C)C(=O)SC[C@@H](C)C(=O)N1[C@@H](CCC1)C([O-])=O)C(=O)C1CCCCC1 CUZMQPZYCDIHQL-VCTVXEGHSA-L 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000003245 coal Substances 0.000 description 1
- 239000000498 cooling water Substances 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 239000008397 galvanized steel Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 1
- 239000000314 lubricant Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 150000004767 nitrides Chemical class 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 238000010791 quenching Methods 0.000 description 1
- 230000000171 quenching effect Effects 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
- 238000010583 slow cooling Methods 0.000 description 1
- 238000002791 soaking Methods 0.000 description 1
Landscapes
- Heat Treatment Of Sheet Steel (AREA)
Abstract
Description
【発明の詳細な説明】 ［産業上の利用分野］ 本発明はプレス成形用の冷延鋼板の製造方法に関する。[Detailed description of the invention] [Industrial application field] The present invention relates to a method of manufacturing a cold rolled steel plate for press forming.
［従来の技術］
プレス成形性に優れた冷延鋼板を極低炭素鋼に１゛１や
Ｎｂを添加して製造する方法はよく知られている。特開
昭６］、−２７６９３０号公報は、成分を調整した極低
Ｃ−Ｔｉ−Ｎｂ系の鋼の、熱延条件、冷却条件、巻取条
件、冷延条件、連続焼鈍条件を特定の範囲に制御して、
冷延薄板を製造する方法である。熱延での仕上圧延終了
後、０．５ｓ以内に冷却を開始して熱延結晶組織を微細
にし、深絞り性の向上を図る方法が開示されている。し
かしこの方法は熱延直後に冷却を開始する方法で、仕上
圧延機の直後に大量に発生する水蒸気で、仕上圧延機の
直後に通常設けられている板厚計や温度計による圧延材
の板厚や温度のＨ１測が困難となる方法で、従って通常
の圧延機では熱延制御が困難となる。尚この発明では平
均冷却速度１０℃／ｓ以上で圧延材を冷却するが、冷却
速度の限定には格別の記載がなく、従って１０℃／ｓ以
上とは例えば実施例の３０℃／ｓを指す。[Prior Art] A method of manufacturing a cold-rolled steel sheet with excellent press formability by adding 1<1> or Nb to ultra-low carbon steel is well known. JP-A No. 6], -276930 discloses hot rolling conditions, cooling conditions, coiling conditions, cold rolling conditions, and continuous annealing conditions of extremely low C-Ti-Nb steel with adjusted composition within a specific range. control to
This is a method for manufacturing cold-rolled thin sheets. A method is disclosed in which cooling is started within 0.5 seconds after finish rolling in hot rolling to refine the hot rolling crystal structure and improve deep drawability. However, in this method, cooling is started immediately after hot rolling, and a large amount of water vapor is generated immediately after the finishing mill. This method makes H1 measurement of thickness and temperature difficult, and therefore hot rolling control becomes difficult with a normal rolling mill. In this invention, the rolled material is cooled at an average cooling rate of 10° C./s or more, but there is no specific description of the limitation on the cooling rate, so 10° C./s or more refers to, for example, 30° C./s in the example. .
一方Ｔｉ又はＴｉ及びＮｂを含有する冷延鋼板は、Ｔｉ
炭化物やＮｂ炭窒化物が熱延板で十分に析出していると
、高い深絞り性すなわち高いプレス成形性が得られる。On the other hand, cold-rolled steel sheets containing Ti or Ti and Nb are
When carbides and Nb carbonitrides are sufficiently precipitated in the hot rolled sheet, high deep drawability, that is, high press formability can be obtained.
箱型焼鈍法では焼鈍時間が長いため、低温で巻取っても
、焼鈍中にＴ」炭化物やＮｂ炭窒化物が析出するため良
好な深絞り性、すなわち良好なプレス成形性が得られる
。しかし連続焼鈍法は焼鈍時間が短かいため、焼鈍中に
１１炭化物やＮｂ炭窒化物は析出し難い。従って連続焼
鈍法では、熱延鋼板を高温で巻取り、巻取ってからＴｉ
炭化物やＮｂ炭窒化物を析出させる場合が多い。しかし
高温で巻取ると鋼板の表面の酸化が大きく酸洗性が低下
するし、又高温で巻取ってもコイルの内周部や外周部は
冷却速度が大きいため、コイルの均質性が損われるに至
る。In the box annealing method, the annealing time is long, so even if the material is wound at a low temperature, T'' carbide and Nb carbonitride precipitate during annealing, resulting in good deep drawability, that is, good press formability. However, since the continuous annealing method has a short annealing time, 11 carbides and Nb carbonitrides are difficult to precipitate during annealing. Therefore, in the continuous annealing method, hot-rolled steel sheets are wound up at high temperatures, and then Ti
In many cases, carbides and Nb carbonitrides are precipitated. However, when coiled at high temperatures, the surface of the steel plate is greatly oxidized, reducing pickling properties.Also, even when coiled at high temperatures, the inner and outer peripheries of the coil cool at a high rate, which impairs the uniformity of the coil. leading to.
［発明が解決しようとする課題］
本発明は低温巻取りで、Ｔｉ炭化物やＮｂ炭窒化物が析
出した熱延鋼板を製造し、これを用いプレス成形性すな
わち深絞り性のよい鋼板を、連続焼鈍法によって製造す
る方法を開示する事を１」的としている。[Problems to be Solved by the Invention] The present invention involves producing a hot-rolled steel sheet with precipitated Ti carbides and Nb carbonitrides by low-temperature winding, and using this to continuously produce a steel sheet with good press formability, that is, deep drawability. The objective is to disclose a manufacturing method using an annealing method.
［課題を解決するための手段］
本発明は、（］）重量％で、Ｃ： ０．００５以下、Ｓ
ｌ：１．０以下、Ｍｎ：２．０以下、Ｐ：０．１５以下
、Ｓ：０．０５以下、 ５ｏｌＡ ｆｌ ： ０．１以
下、 Ｎ ： ０．００８以下、Ｔｉ：０．００４〜０
．２で必要に応じてＢ ： ０．０００５〜０．００３
０を含有し、残部Ｆｅおよび不可避的不純物からなる成
分の鋼を、熱間圧延に際し、Ａｒ３点以」二の温度で仕
−ヒげ圧延を終了し、その後冷却開始温度がＡｒ３点以
上で、冷却終了温度が（Ａｒ３−１．０°Ｃ）−（Ａｒ
３−１ｏｏ’ｃ）の温度域を、５０℃／ ｓ −４００
℃／ｓの冷却速度で冷却し、その後２ｓ〜２０ｓ保持し
、６５０℃以下で巻取り、その後常法に従って冷間圧延
・連続焼鈍することを特徴とする、プレス成形性に優れ
た冷延鋼板の製造方法であり、又
（２）重量％で、Ｃ： ０．００５以下、Ｓｉ：１．０
以下。[Means for Solving the Problems] The present invention provides (]) in weight%, C: 0.005 or less, S
l: 1.0 or less, Mn: 2.0 or less, P: 0.15 or less, S: 0.05 or less, 5olAfl: 0.1 or less, N: 0.008 or less, Ti: 0.004-0
．． 2 and B as necessary: 0.0005 to 0.003
When hot rolling a steel containing 0 and the remainder consisting of Fe and unavoidable impurities, finish rolling at a temperature of Ar3 or higher, and then cooling start temperature at Ar3 or higher, The cooling end temperature is (Ar3-1.0°C)-(Ar
3-1oo'c) temperature range at 50℃/s -400
A cold-rolled steel sheet with excellent press formability, characterized by being cooled at a cooling rate of ℃/s, then held for 2s to 20s, coiled at 650℃ or less, and then cold-rolled and continuously annealed according to a conventional method. (2) In weight%, C: 0.005 or less, Si: 1.0
below.
Ｍｎ：２．Ｏ以下、Ｐ：０．１５以下、Ｓ：０．０５以
下、 Ｓ。Mn:2. O or less, P: 0.15 or less, S: 0.05 or less, S.
ＩＡＱ：０．１以下、 Ｎ ： ０．００８以下、 Ｔ
ｉ ： ０．００４〜０゜２、 Ｎｂ ： ０．００４
〜０．０５で必要に応じ、Ｂ ： ０．０００５〜０．
００３０を含有し、残部Ｆｅおよび不可避的不純物から
なる成分の鋼を、熱間圧延に際し、Ａｒ３点以」−の温
度で仕北げ圧延を終了し、その後冷却開始温度がＡｒ３
点以上で冷却終了温度が（Ａｒ３−１００Ｃ）−（Ａｒ
３−１００℃）の温度域を、５０°Ｃ／ ｓ −４００
℃／ ｓの冷却速度で冷却し、その後２５〜２０ｓ保持
し、６５０°Ｃ以下で巻取り、その後常法に従って冷間
圧延・連続焼鈍することを特徴とする、プレス成形性に
優れた冷延鋼板の製造方法である。IAQ: 0.1 or less, N: 0.008 or less, T
i: 0.004~0゜2, Nb: 0.004
~0.05 as necessary, B: 0.0005~0.
When hot rolling a steel containing 0030 and the balance consisting of Fe and unavoidable impurities, finish rolling is completed at a temperature of Ar3 or higher, and then the cooling start temperature is set to Ar3.
The cooling end temperature is (Ar3-100C)-(Ar
3-100℃), 50℃/s -400℃
Cold rolled with excellent press formability, characterized by cooling at a cooling rate of ℃/s, then holding for 25 to 20 seconds, coiling at 650℃ or less, and then cold rolling and continuous annealing according to conventional methods. This is a method for manufacturing steel plates.
［作用コ 以下に本発明を具体的に説明する。[Action Co. The present invention will be specifically explained below.
Ｃは０．００５％以下とする。プレス加工性を向上させ
るにはＣは少ない方がよい。又Ｃがｏ、ｏｏｓ％を超え
るとこれを固定するためにＴｉやＮｂの添加量が増加し
コストアップとなる。C shall be 0.005% or less. In order to improve press workability, it is better to have less C. Furthermore, if C exceeds o or oos%, the amount of Ti or Nb added increases to fix it, resulting in an increase in cost.
Ｓｌは１．０％以下である。Ｓｉは強度を高めるのに有
効な元素で、必要とする引張強度に応じて添加できるが
、１．０％を超えると溶融めっき性や化成処理性が損わ
れる。Sl is 1.0% or less. Si is an effective element for increasing strength and can be added depending on the required tensile strength, but if it exceeds 1.0%, hot-dip plating properties and chemical conversion properties are impaired.
Ｍｒ＋ｔ＋Ｓｉと同様に、必要とする引張強度に応じて
添加できるが、極低炭でＭｎが２．０％以上は精錬コス
１〜が高くなるし、又Ｍｎがあまり高過ぎると加工性も
損われる。Like Mr+t+Si, it can be added depending on the required tensile strength, but if the Mn content is 2.0% or more in ultra-low coal, the refining cost will be high, and if the Mn content is too high, the workability will be impaired. .
Ｓは硫化物系介在物を生成し、プレス成形性を劣化させ
るので少ないほうがよく、０．０５％以下とする。Ｐは
強度上昇に有効な元素で、高い引張強度が望まれる場合
は積極的に添加する。しかし０．１５％を超えると溶接
脆性を起し易くなる。Since S forms sulfide-based inclusions and deteriorates press formability, it is better to have a smaller amount, and it is set to 0.05% or less. P is an element effective in increasing strength, and is actively added when high tensile strength is desired. However, if it exceeds 0.15%, weld brittleness tends to occur.
５ｏｌＡ ｆｌは溶鋼を脱酸しＴｉやＮｂの歩留りを向
上させるために含有させる。しかし過剰に添加すると鋼
板のプレス成形性を損うために０．１％を上限とする。5olA fl is contained in order to deoxidize the molten steel and improve the yield of Ti and Nb. However, if added in excess, the press formability of the steel plate will be impaired, so the upper limit is set at 0.1%.
Ｎはｏ、ｏｏｇ％以下である。Ｎが高過ぎると、ｌｉや
Ｔ１やＮｂの添加量が増加してコストアップとなるし、
又プレス成形性が損われる。N is o, oog% or less. If the N content is too high, the amount of li, T1, and Nb added will increase, resulting in an increase in cost.
Moreover, press formability is impaired.
本発明では、鋼中のＣ，Ｎを析出固定し、良好なプレス
成形性を得るためにＴｉやＮｂを添加する。In the present invention, Ti and Nb are added to precipitate and fix C and N in the steel and to obtain good press formability.
Ｔｉは０．００４％以下ではＣやＮが十分に析出固定さ
れないために冷延鋼板の時効性が悪い。Ｔｉの含有は０
．２％で十分で、過剰の添加は経済性の点で好ましくな
い。尚Ｔｉ窒化物は鋼への溶解度積が小さいためスラブ
で析出している。Ｔｉ炭化物は溶解度積が大きく、その
多くは熱延での巻取り段階や焼純生に析出するが、後述
する如く本発明では低温巻取りでこれを析出させる。When Ti is less than 0.004%, C and N are not sufficiently precipitated and fixed, resulting in poor aging properties of the cold rolled steel sheet. Ti content is 0
．． 2% is sufficient, and excessive addition is not preferable from the economic point of view. Note that Ti nitride precipitates in the slab because its solubility product in steel is small. Ti carbide has a large solubility product, and most of it is precipitated during the coiling stage of hot rolling or during sintering, but as described later, in the present invention, it is precipitated during low-temperature coiling.
Ｎｂも同様の理由で０．００４〜０．０５％含有させる
。尚Ｎｂの炭窒化物も熱延での巻取り段階や焼鈍中に析
出するが、後述する如く本発明では低温巻取りでこれを
析出させる。Nb is also contained in an amount of 0.004 to 0.05% for the same reason. Although Nb carbonitride is also precipitated during the winding stage of hot rolling and annealing, in the present invention, it is precipitated during low-temperature winding as will be described later.
本発明では、二次加工脆性を抑制する場合にはＢを添加
する。ｏ、ｏｏｏｓ％以上添加すると二次加工脆性は著
しく改善される。しかし０．００３％以上添加しても効
果は飽和する。In the present invention, B is added when suppressing secondary processing brittleness. When added in an amount of o, oos% or more, secondary work brittleness is significantly improved. However, even if 0.003% or more is added, the effect is saturated.
本発明の熱間圧延の仕上げ圧延温度はＡｒ３点以上であ
る。Ａｒ３点以下では熱延板に粗大粒が発生したり加工
組織が残留し、冷延・焼鈍後の深絞り性を低下させる。The finish rolling temperature of the hot rolling of the present invention is Ar3 point or higher. If the Ar point is 3 or less, coarse grains are generated in the hot rolled sheet or a processed structure remains, reducing the deep drawability after cold rolling and annealing.
次に本発明の詳細な説明する。本発明では冷却開始温度
がＡｒ３点以上で冷却終了温度が（Ａｒ３−１０℃）〜
（Ａｒ３−１００°Ｃ）の温度域を、５０℃／５−４０
０℃／ｓの冷却速度で冷却しその後２ｓ〜２０ｓ保持す
る。この急冷却と保持は従来知られてぃなかった下記の
効果を伴う。即ち従来は６５０℃以下の低い温度で巻取
ると、巻取り温度が低いため、Ｔｉ炭化物やＮｂ炭窒化
物が核発生し難く、また析出速度が遅いため、析出物が
析出を完了しないで、これを冷延・連続焼鈍した冷延鋼
板はプレス成形性の低い製品となった。しかし本発明の
急冷却を行うと保持の間にＴｉ炭化物やＮｂ炭窒化物が
結晶粒内に均一に析出し、６５０℃以下の低い巻取り後
の緩冷却過程でも、既に析出したＴｉ炭化物やＮｂ炭窒
化物が成長する。この結果連続焼鈍法によってもプレス
成形性のよい冷延鋼板となる。この理由は、冷却開始温
度がＡｒ３点以上で冷却終了温度が（Ａｒ３−１０℃）
〜（Ａｒ３−１００℃）の温度域を急冷却することによ
って、生成するα粒に転位を導入し、Ｔｉ炭化物やＮｂ
炭窒化物の析出サイトを与えるためと考えられる。この
ためには５０℃／ｓ以上の冷却速度が必要である。冷却
速度は４００℃／ｓ以上であってもよいが、４００℃／
ｓが達成容易な範囲である。Next, the present invention will be explained in detail. In the present invention, the cooling start temperature is Ar3 point or higher and the cooling end temperature is (Ar3-10℃) ~
(Ar3-100°C) temperature range is 50°C/5-40
Cool at a cooling rate of 0° C./s and then hold for 2 to 20 seconds. This rapid cooling and holding is accompanied by the following effects that were previously unknown. That is, conventionally, when winding is performed at a low temperature of 650° C. or lower, Ti carbide and Nb carbonitride are difficult to generate nuclei due to the low winding temperature, and the precipitation rate is slow, so the precipitates do not complete precipitation. The cold-rolled steel sheet obtained by cold rolling and continuous annealing is a product with low press formability. However, when the rapid cooling of the present invention is performed, Ti carbides and Nb carbonitrides precipitate uniformly within the crystal grains during holding, and even during the slow cooling process after winding at a temperature of 650°C or less, the already precipitated Ti carbides and Nb carbonitride grows. As a result, a cold-rolled steel sheet with good press formability can be obtained even by continuous annealing. The reason for this is that the cooling start temperature is Ar3 point or higher and the cooling end temperature is (Ar3-10℃).
By rapidly cooling in the temperature range of ~(Ar3-100℃), dislocations are introduced into the generated α grains, forming Ti carbides and Nb
This is thought to be to provide a site for carbonitride precipitation. For this purpose, a cooling rate of 50° C./s or higher is required. The cooling rate may be 400°C/s or more, but the cooling rate is 400°C/s or more.
s is an easily achievable range.
冷却終了温度は（Ａｒ３−１０℃）−（Ａｒ３ １００
℃）である。冷却終了温度が高過ぎるとα相の体積率が
少なく、析出は一部の結晶粒にしか起らない。また低過
ぎると、析出速度が遅く、導入した転位に有効に析出せ
ず、析出する前に転位が消滅してしまう。従って急冷却
終了温度は（Ａｒ３−１０℃）〜（Ａｒ３−１００℃）
である。急冷終了温度を好ましくは（Ａｒ３−１０℃）
〜（Ａｒ３−８０℃）、最も好ましくは（Ａｒ３−１
０℃）〜（Ａｒ３−５０℃）とすると、さらに高い深絞
り性が得られる。The cooling end temperature is (Ar3-10℃)-(Ar3 100
℃). If the cooling end temperature is too high, the volume fraction of the α phase will be small and precipitation will occur only in some crystal grains. On the other hand, if it is too low, the precipitation rate will be slow, and the introduced dislocations will not be effectively precipitated, and the dislocations will disappear before they are precipitated. Therefore, the rapid cooling end temperature is (Ar3-10℃) ~ (Ar3-100℃)
It is. Preferably the quenching end temperature (Ar3-10℃)
~(Ar3-80°C), most preferably (Ar3-1
0°C) to (Ar3-50°C), even higher deep drawability can be obtained.
次に本発明ではＴｉ炭化物やＮｂ炭窒化物を析出させる
ため２ｓ〜２０ｓ保持する。本発明で保持とは、冷却速
度で２０℃／ｓ以下の冷却速度、即ちランナウトテーブ
ル上での通板ロールによる冷却やその冷却水による弱水
冷、温度計測等の水切り等による部分的な冷却、空冷あ
るいはそれ以下の冷却速度に熱延板を保つことをいう。Next, in the present invention, the temperature is maintained for 2 to 20 seconds in order to precipitate Ti carbide and Nb carbonitride. In the present invention, holding means cooling at a cooling rate of 20°C/s or less, that is, cooling with a passing roll on a runout table, weak water cooling with cooling water, partial cooling by draining water such as temperature measurement, etc. This refers to maintaining a hot rolled sheet at a cooling rate of air cooling or lower.
保持中の温度降下を少なくするための、電気、ガス等を
用いたヒーターや保温カバーなどの使用は、保持中の温
度降下を防ぎ、析出量を増加させるために好ましい。保
持時間は２８以上あればＴｉ炭化物やＮｂ炭窒化物は数
多く転位線上に析出しうるが、この保持時間は４Ｓ以上
、最も好ましくは６８以上とするのが更によい。保持時
間は長い方が析出量が増大して好ましいが、保持時間を
２０ｓ以上とすると仕上圧延機から巻取機までのライン
長さが著しく長くなり設備が大規模となる。In order to reduce the temperature drop during holding, it is preferable to use a heater using electricity, gas, etc., a heat insulating cover, etc. to prevent the temperature drop during holding and increase the amount of precipitation. If the holding time is 28 or more, a large number of Ti carbides and Nb carbonitrides can be precipitated on the dislocation lines, but this holding time is more preferably 4S or more, most preferably 68 or more. A longer holding time is preferable because the amount of precipitation increases, but if the holding time is 20 seconds or more, the length of the line from the finishing mill to the winding machine becomes significantly long and the equipment becomes large-scale.
また保持時間をできるだけ長くとるため、通常仕上圧延
機出側に配置される板厚計や温度計の作動しこ支障をき
たさない範囲しこおいて、保持前の急冷を行う冷却設備
は仕上圧延機にできるだけ近づけて配置することが好ま
しい。In addition, in order to make the holding time as long as possible, the cooling equipment that performs rapid cooling before holding is installed in the finishing rolling mill to the extent that it does not interfere with the operation of the plate thickness gauge and thermometer that are normally placed at the exit side of the finishing rolling mill. It is preferable to place it as close to the machine as possible.
保持を終了する温度が低くなると析出する速度が小さく
なり保持を行う効果が小さくなる。好ましくは（Ａｒ３
−１００°Ｃ）以上で保持を終了することがよい。When the temperature at which holding ends is lowered, the rate of precipitation decreases and the holding effect becomes smaller. Preferably (Ar3
-100°C) or higher is preferable.
本発明では６５０°Ｃ以上の温度で巻取る。６５０℃以
下では鋼板の表面の酸化が少なく酸洗性が良好であり、
又全長に亘って、コイルの内周部も外周部も均質な熱延
板が得られる。In the present invention, winding is performed at a temperature of 650°C or higher. At temperatures below 650°C, there is little oxidation on the surface of the steel plate and the pickling properties are good.
Moreover, a hot-rolled sheet can be obtained in which both the inner and outer circumferential parts of the coil are homogeneous over the entire length.
また、熱間圧延に際しスラブ加熱温度は１．０００〜１
３００°Ｃとすれば良好な深絞り性が得られる。好まし
くは］０００〜］］５０°Ｃとするとさらに良好な深絞
り性が得られる。また連続鋳造後、直送圧延を行う場合
にも同様の効果が得られる。In addition, during hot rolling, the slab heating temperature is 1.000 to 1.
If the temperature is 300°C, good deep drawability can be obtained. Preferably, when the temperature is [000~]]50°C, even better deep drawability can be obtained. Similar effects can also be obtained when direct rolling is performed after continuous casting.
本発明で製造した熱延鋼板は常法で冷間圧延や連続焼鈍
を行う。冷間圧延や連続焼鈍の条件は特に限定するもの
でないが、冷間圧延率は４０〜９５％が、望ましくは７
０〜９０％にすると非常に高いプレス成形性の冷延鋼板
が得られる。又連続焼鈍もあまりに高い焼鈍温度は好ま
しくないが、通常の連続焼鈍条件でプレス成形性に優れ
た冷延鋼板となる。The hot-rolled steel sheet produced according to the present invention is cold rolled and continuously annealed by conventional methods. The conditions for cold rolling and continuous annealing are not particularly limited, but the cold rolling rate is 40 to 95%, preferably 7.
When it is 0 to 90%, a cold rolled steel sheet with very high press formability can be obtained. Further, in continuous annealing, too high annealing temperature is not preferred, but under normal continuous annealing conditions, a cold rolled steel sheet with excellent press formability can be obtained.
冷延、焼鈍を行い、冷延鋼板となした後、その後の工程
で亜鉛めっき、すずめつき、クロムメツキなど、種々の
めっきをその用途に合わせて行ってよい。また焼鈍後、
引き続いて溶融亜鉛めっき等を行うことも用途に応じて
行ってよい。この際ＮｂとＴｉを添加した鋼を用いると
めっき層の密着性がよりよい亜鉛めっき鋼板が得られ好
ましい。After cold rolling and annealing to form a cold rolled steel sheet, various platings such as galvanizing, tin plating, chrome plating, etc. may be performed in subsequent steps depending on the purpose. Also, after annealing,
Subsequently, hot-dip galvanizing or the like may be performed depending on the application. In this case, it is preferable to use steel to which Nb and Ti are added because a galvanized steel sheet with better adhesion of the plating layer can be obtained.
さらに焼鈍後、調質圧延、防錆処理、潤滑剤の塗布等も
必要に応じて行ってよい。Furthermore, after annealing, skin pass rolling, rust prevention treatment, application of lubricant, etc. may be performed as necessary.
［実施例コ
通常の工程にしたがって溶製された鋼を連続鋳造によっ
て２４５ｍｍ厚のスラブとした。鋼の化学成分を第１表
に示す。[Example 1] A slab of 245 mm thick was made by continuous casting of steel melted according to the usual process. The chemical composition of the steel is shown in Table 1.
その後］］５０℃で１．．５ｈｒ均熱処理後、粗圧延、
仕上圧延を行い、所定の温度で巻取り、ホットコイルと
なした。その後酸洗を行った後、８０％の冷間圧延を行
い、７６０°Ｃで４０秒間の連続焼鈍を行い０．６％の
副室圧延を行って冷延鋼板を製造した。After that]] 1. at 50°C. ．． After soaking for 5 hours, rough rolling,
Finish rolling was performed and coiled at a predetermined temperature to form a hot coil. Thereafter, after pickling, 80% cold rolling was performed, continuous annealing was performed at 760° C. for 40 seconds, and 0.6% pre-chamber rolling was performed to produce a cold rolled steel sheet.
第２表に熱延条件と冷延鋼板のｒ値を示す。第２表に示
すごとく、本発明範囲内の化学成分の鋼を用い、さらに
本発明範囲内の熱延での圧延終了温度および冷却開始温
度、冷却終了温度そして冷却速度で冷却し、保持を行う
ことによって、深絞り性に優れた冷延鋼板を製造するこ
とができることがわかる。Table 2 shows the hot rolling conditions and the r value of the cold rolled steel sheets. As shown in Table 2, steel with chemical composition within the range of the present invention is used, and the steel is cooled and held at the rolling end temperature, cooling start temperature, cooling end temperature, and cooling rate within the range of the present invention. It can be seen that this makes it possible to produce a cold-rolled steel sheet with excellent deep drawability.
深絞り性の指評としてランクフォード値（ｒ値）を用い
た。ｒ値は圧延方向、圧延方向から±４５°傾いた方向
、圧延直角方向の値を平均したものを用いた。The Lankford value (r value) was used as an index of deep drawability. The r value used was the average value of the values in the rolling direction, a direction tilted by ±45° from the rolling direction, and a direction perpendicular to the rolling direction.
［発明の効果コ
本発明は、低温巻取りのため、酸洗性に優れ且第
２ 表
＊保持：空冷（冷却速度：５℃／５ｅｅ） ＊保持：
保温カバー（冷却速度＝０．２℃／５ｅｅ）つコイルの
内周部や外周部の材質が安定している。[Effects of the Invention] The present invention has excellent pickling properties and
2 Table *Holding: Air cooling (cooling rate: 5℃/5ee) *Holding:
Heat insulation cover (cooling rate = 0.2°C/5ee) The material of the inner and outer periphery of the coil is stable.
更に本発明は、低温巻取りであるが、Ｔｉ炭化物やＮｂ
炭窒化物が析出しているため、連続焼鈍法を用いた冷間
圧延で、深絞り性の優れた冷延鋼板が製造できる方法で
あり、産業上の効果が大きい。Furthermore, although the present invention involves low-temperature winding, Ti carbide and Nb
Because carbonitrides are precipitated, cold rolling using continuous annealing is a method that can produce cold rolled steel sheets with excellent deep drawability, and has great industrial effects.
特許出願人 新日本製鐵株式会社Patent applicant: Nippon Steel Corporation
Claims (2)
００８以下、Ｔｉ：０．００４〜０．２、で必要に応じ
てＢ：０．０００５〜０．００３０を含有し、残部Ｆｅ
および不可避的不純物からなる成分の鋼を、熱間圧延に
際し、Ａｒ３点以上の温度で仕上げ圧延を終了し、その
後冷却開始温度がＡｒ３点以上で冷却終了温度が（Ａｒ
３−１０℃）〜（Ａｒ３−１００℃）の温度域を、５０
℃／ｓ〜４００℃／ｓの冷却速度で冷却し、その後２ｓ
〜２０ｓ保持し、６５０℃以下で巻取り、その後常法に
従って冷間圧延・連続焼鈍することを特徴とする、プレ
ス成形性に優れた冷延鋼板の製造方法。(1) In weight%, C: 0.005 or less, Si: 1.0 or less, Mn: 2.0 or less, P: 0.15 or less, S: 0.05 or less, SolAl: 0.1 or less, N: 0.
008 or less, Ti: 0.004 to 0.2, B: 0.0005 to 0.0030 as required, and the balance is Fe.
During hot rolling of steel with components consisting of and unavoidable impurities, finish rolling is completed at a temperature of Ar3 or higher, and then the cooling start temperature is Ar3 or higher and the cooling end temperature is (Ar
3-10℃) to (Ar3-100℃), 50℃
Cool at a cooling rate of ℃/s to 400℃/s, then 2s
A method for producing a cold-rolled steel sheet with excellent press formability, characterized by holding the steel sheet for ~20 seconds, winding it at 650°C or less, and then cold rolling and continuous annealing according to a conventional method.
００８以下、Ｔｉ：０．００４〜０．２、Ｎｂ：０．０
０４〜０．０５、 で必要に応じ、Ｂ：０．０００５〜０．００３０を含有
し、残部Ｆｅおよび不可避的不純物からなる成分の鋼を
、熱間圧延に際し、Ａｒ３点以上の温度で仕上げ圧延を
終了し、その後冷却開始温度がＡｒ３点以上で冷却終了
温度が（Ａｒ３−１０℃）〜（Ａｒ３−１００℃）の温
度域を、５０℃／ｓ〜４００℃／ｓの冷却速度で冷却し
、その後２ｓ〜２０ｓ保持し、６５０℃以下で巻取り、
その後常法に従って冷間圧延・連続焼鈍することを特徴
とする、プレス成形性に優れた冷延鋼板の製造方法。(2) In weight%, C: 0.005 or less, Si: 1.0 or less, Mn: 2.0 or less, P: 0.15 or less, S: 0.05 or less, SolAl: 0.1 or less, N: 0.
008 or less, Ti: 0.004 to 0.2, Nb: 0.0
04 to 0.05, if necessary, B: 0.0005 to 0.0030, and the balance consists of Fe and unavoidable impurities, finish rolling at a temperature of Ar3 point or higher during hot rolling. After that, the temperature range where the cooling start temperature is Ar3 point or higher and the cooling end temperature is (Ar3-10℃) to (Ar3-100℃) is cooled at a cooling rate of 50℃/s to 400℃/s. , then held for 2s to 20s and wound at 650°C or less,
A method for producing a cold-rolled steel sheet with excellent press formability, which is then subjected to cold rolling and continuous annealing according to a conventional method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1009088A JPH01188630A (en) | 1988-01-20 | 1988-01-20 | Manufacture of cold rolled steel sheet having superior press formability |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1009088A JPH01188630A (en) | 1988-01-20 | 1988-01-20 | Manufacture of cold rolled steel sheet having superior press formability |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH01188630A true JPH01188630A (en) | 1989-07-27 |
Family
ID=11740633
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1009088A Pending JPH01188630A (en) | 1988-01-20 | 1988-01-20 | Manufacture of cold rolled steel sheet having superior press formability |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH01188630A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH02259024A (en) * | 1989-03-31 | 1990-10-19 | Kobe Steel Ltd | Production of cold rolled soft steel sheet excellent in deep drawability |
| JP2012167374A (en) * | 2012-03-16 | 2012-09-06 | Sumitomo Metal Ind Ltd | Method for manufacturing cold-rolled steel sheet |
| JP2013100606A (en) * | 2013-01-10 | 2013-05-23 | Nippon Steel & Sumitomo Metal Corp | Method for producing cold-rolled steel sheet |
-
1988
- 1988-01-20 JP JP1009088A patent/JPH01188630A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH02259024A (en) * | 1989-03-31 | 1990-10-19 | Kobe Steel Ltd | Production of cold rolled soft steel sheet excellent in deep drawability |
| JP2012167374A (en) * | 2012-03-16 | 2012-09-06 | Sumitomo Metal Ind Ltd | Method for manufacturing cold-rolled steel sheet |
| JP2013100606A (en) * | 2013-01-10 | 2013-05-23 | Nippon Steel & Sumitomo Metal Corp | Method for producing cold-rolled steel sheet |
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