JPH0413816A - Production of galvanized steel sheet having high moldability - Google Patents
Production of galvanized steel sheet having high moldabilityInfo
- Publication number
- JPH0413816A JPH0413816A JP11786190A JP11786190A JPH0413816A JP H0413816 A JPH0413816 A JP H0413816A JP 11786190 A JP11786190 A JP 11786190A JP 11786190 A JP11786190 A JP 11786190A JP H0413816 A JPH0413816 A JP H0413816A
- Authority
- JP
- Japan
- Prior art keywords
- less
- steel
- annealing
- steel sheet
- 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.)
- Pending
Links
- 229910001335 Galvanized steel Inorganic materials 0.000 title claims abstract description 16
- 239000008397 galvanized steel Substances 0.000 title claims abstract description 16
- 238000004519 manufacturing process Methods 0.000 title claims description 15
- 238000000137 annealing Methods 0.000 claims abstract description 61
- 229910052758 niobium Inorganic materials 0.000 claims abstract description 25
- 229910052748 manganese Inorganic materials 0.000 claims abstract description 9
- 238000001816 cooling Methods 0.000 claims abstract description 5
- 229910052757 nitrogen Inorganic materials 0.000 claims description 14
- 238000000034 method Methods 0.000 claims description 11
- 229910052717 sulfur Inorganic materials 0.000 claims description 11
- 238000005246 galvanizing Methods 0.000 claims description 9
- 239000012535 impurity Substances 0.000 claims description 8
- 229910052698 phosphorus Inorganic materials 0.000 claims description 4
- 229910000831 Steel Inorganic materials 0.000 abstract description 78
- 239000010959 steel Substances 0.000 abstract description 78
- 238000005098 hot rolling Methods 0.000 abstract description 12
- 239000013078 crystal Substances 0.000 abstract description 10
- 238000007747 plating Methods 0.000 abstract description 7
- 238000001556 precipitation Methods 0.000 abstract description 5
- 238000001953 recrystallisation Methods 0.000 abstract description 5
- 150000004767 nitrides Chemical class 0.000 abstract description 4
- 150000001247 metal acetylides Chemical class 0.000 abstract description 3
- 150000003568 thioethers Chemical class 0.000 abstract description 3
- 229910001209 Low-carbon steel Inorganic materials 0.000 abstract description 2
- 230000000694 effects Effects 0.000 description 17
- 239000006104 solid solution Substances 0.000 description 11
- 239000000463 material Substances 0.000 description 10
- 238000005097 cold rolling Methods 0.000 description 9
- 229910052799 carbon Inorganic materials 0.000 description 8
- 239000010960 cold rolled steel Substances 0.000 description 7
- 239000002244 precipitate Substances 0.000 description 7
- 229910045601 alloy Inorganic materials 0.000 description 6
- 239000000956 alloy Substances 0.000 description 6
- 239000000203 mixture Substances 0.000 description 6
- 238000005096 rolling process Methods 0.000 description 6
- 230000032683 aging Effects 0.000 description 5
- 238000002791 soaking Methods 0.000 description 5
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 4
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 4
- 230000002411 adverse Effects 0.000 description 4
- 238000005275 alloying Methods 0.000 description 4
- 229910052725 zinc Inorganic materials 0.000 description 4
- 239000011701 zinc Substances 0.000 description 4
- 238000009749 continuous casting Methods 0.000 description 3
- 230000007423 decrease Effects 0.000 description 3
- 238000002844 melting Methods 0.000 description 3
- 230000008018 melting Effects 0.000 description 3
- 238000012545 processing Methods 0.000 description 3
- 238000012360 testing method Methods 0.000 description 3
- 230000002159 abnormal effect Effects 0.000 description 2
- 229910052804 chromium Inorganic materials 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 230000007797 corrosion Effects 0.000 description 2
- 238000005260 corrosion Methods 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 230000006866 deterioration Effects 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 238000002347 injection Methods 0.000 description 2
- 239000007924 injection Substances 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 238000004804 winding Methods 0.000 description 2
- 241000219198 Brassica Species 0.000 description 1
- 235000003351 Brassica cretica Nutrition 0.000 description 1
- 235000003343 Brassica rupestris Nutrition 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 206010010904 Convulsion Diseases 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- QKSKPIVNLNLAAV-UHFFFAOYSA-N bis(2-chloroethyl) sulfide Chemical compound ClCCSCCCl QKSKPIVNLNLAAV-UHFFFAOYSA-N 0.000 description 1
- 239000004566 building material Substances 0.000 description 1
- 229910001567 cementite Inorganic materials 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 239000012141 concentrate Substances 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 238000005261 decarburization Methods 0.000 description 1
- 230000002542 deteriorative effect Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- KSOKAHYVTMZFBJ-UHFFFAOYSA-N iron;methane Chemical compound C.[Fe].[Fe].[Fe] KSOKAHYVTMZFBJ-UHFFFAOYSA-N 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 235000010460 mustard Nutrition 0.000 description 1
- 238000005554 pickling Methods 0.000 description 1
- 230000002940 repellent Effects 0.000 description 1
- 239000005871 repellent Substances 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000007788 roughening Methods 0.000 description 1
- 238000007665 sagging Methods 0.000 description 1
- 239000002893 slag Substances 0.000 description 1
- 238000009849 vacuum degassing Methods 0.000 description 1
Landscapes
- Heat Treatment Of Sheet Steel (AREA)
- Coating With Molten Metal (AREA)
- Heat Treatment Of Steel (AREA)
Abstract
Description
【発明の詳細な説明】
産業上の利用分野
この発明は、高い成形性を有する。溶融亜鉛めっき鋼板
の製造方法に関する。DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention has high moldability. This invention relates to a method for producing hot-dip galvanized steel sheets.
従来の技術
近年、めっき鋼板、例えば合金化処理溶融亜鉛めっき鋼
板は、耐食性、塗装性が良好であるところから、自動車
向、家電向、建材向の材料として急激に需要が増大しつ
つある。特に自動車同材料においては、耐食性、塗装性
と共に、複雑な形状にプレス加工できるような優れた成
形加工性や、外装材においてはストレッチャーストレイ
ンが発生しないよう降伏点伸び（以下「ＹＰＥ」という
）がなく、非時効性であることが要求される。BACKGROUND OF THE INVENTION In recent years, demand for galvanized steel sheets, such as alloyed hot-dip galvanized steel sheets, has been rapidly increasing as materials for automobiles, home appliances, and building materials because of their good corrosion resistance and paintability. In particular, automotive materials have excellent moldability that allows them to be press-formed into complex shapes, as well as corrosion resistance and paintability, and for exterior materials, yield point elongation (hereinafter referred to as "YPE") is required to prevent stretcher strain. It is required that there is no statute of limitations and that there is no statute of limitations.
優れた成形加工性を持つためには、一般に全延び（以下
「Ｅｌ」という）、ｎ値、ランクフォード値（以下「ｒ
値］という）が高いことが必要であるが、その他に加工
し易いという点からいえば降伏点（以下［ＹＰ、Ｊ と
いう）が低く、引張り強度（以下ｒＴｓＪ という）も
ある程度は低いことが必要である。In order to have excellent moldability, the total elongation (hereinafter referred to as "El"), n value, and Lankford value (hereinafter referred to as "r") are generally required.
In addition, from the viewpoint of ease of processing, it is necessary that the yield point (hereinafter referred to as [YP, J) and tensile strength (hereinafter referred to as rTsJ) be low to some extent. It is.
上記のとおり自動車同材料は、用途に応じて種々の特性
が要求され、そのような特性を満たすべく、新規技術が
数多く提案されているが、その中にＴｉ添加またはＮｂ
添加あるいはＴｉとＮｂの複合添加を行う方法が知られ
ている。As mentioned above, automobile materials are required to have various properties depending on their use, and many new technologies have been proposed to meet these properties.
A method of adding Ti and Nb or adding a combination of Ti and Nb is known.
これらのＴｉ添加またはＮｂ添加あるいはＴｉとＮｂを
複合添加する方法は、いずれも炭・窒化物形成元素とし
てＴｉまたはＮｂを添加することにより、Ｅｌやｒ値を
低下させる鋼中の固溶ＣＮ、Ｓを析出物として固定する
作用を利用したものである。ＴｉやＮｂを窒化物、硫化
物、炭化物を形成するよりも過剰に添加すると、鋼中の
固溶Ｃ，Ｎ、Ｓなどがほとんど存在しなくなる。このた
め、変形を阻害する要因が減少し、深絞り性が非常に増
大する。また、鋼板は固溶Ｃ，Ｎを含まなくなるため、
同時に非時効性となり、ＹＰＥの発生がなくなり、スト
レッチャーストレインが生じないといった利点を有する
。These methods of Ti addition, Nb addition, or combined addition of Ti and Nb all add Ti or Nb as a carbon/nitride forming element to reduce the El and r values by solid solution CN in the steel, This method utilizes the effect of fixing S as a precipitate. If Ti or Nb is added in excess of the amount required to form nitrides, sulfides, or carbides, there will be almost no solid solution C, N, S, etc. in the steel. Therefore, factors that inhibit deformation are reduced, and deep drawability is greatly increased. In addition, since the steel plate no longer contains solid solution C and N,
At the same time, it has the advantage of being non-aging, eliminating the generation of YPE, and eliminating stretcher strain.
したがって連続焼鈍用の深絞り用鋼板の素材は、はとん
どこの種類のものに変りつつあり、ＴｉとＮｂの添加量
については、特公昭６１−３２３７５号公報、特開昭５
９−７４２３１号公報あるいは特開昭６２−１１２７２
９号公報など、数多くの提案が行なわれている。Therefore, the materials for deep drawing steel sheets for continuous annealing are changing to these kinds of materials.
Publication No. 9-74231 or JP-A-62-11272
Many proposals have been made, including Publication No. 9.
発明が解決しようとする課題
前記Ｔｉ添加鋼板は、過剰のＴｉを添加しなければなら
ないので、連続鋳造において溶鋼注入中にノズルの閉塞
や溶損が発生し易い。また、非金属介在物であるＴｉ０
ｚが生成し、大きな表面疵を発生することがあるなど、
製造上の問題がある。Problems to be Solved by the Invention Since the above-mentioned Ti-added steel sheet requires addition of excessive Ti, nozzle clogging and melting damage are likely to occur during continuous casting during injection of molten steel. In addition, Ti0, which is a nonmetallic inclusion,
z may be generated and large surface flaws may occur.
There is a manufacturing issue.
また、Ｎｂ添加鋼板は、Ｎｂ添加により再結晶温度が上
昇するため、良好な特性を得るには連続焼鈍時に高温焼
鈍が必要となる。しかし、あまり高温で焼鈍すると析出
しなＮｂＣが溶解して固溶Ｃが生じ、ＹＰＥが発生して
時効性となる可能性がでてくるという問題がある。In addition, since the recrystallization temperature of the Nb-added steel sheet increases due to the addition of Nb, high-temperature annealing is required during continuous annealing to obtain good properties. However, if annealing is performed at too high a temperature, precipitated NbC will dissolve and solid solution C will be produced, causing the problem that YPE may occur and aging may occur.
ＴｉとＮｂの複合添加鋼板は、これらの両者の短所を減
じると共に、長所を生かそうとして考えられた鋼板であ
る。しかし前記のとおり最良の添加範囲について数多く
の研究がなされているにも係わらず、いまだに各種の説
があり、最良の添加範囲が見い出されていない状況であ
る。A steel plate with a composite addition of Ti and Nb is a steel plate designed to reduce the disadvantages of both of them and take advantage of their advantages. However, as mentioned above, although many studies have been conducted on the best range of addition, there are still various theories and the best range of addition has not yet been found.
一方、自動車業界においては、製造工程の簡素化、部品
数の低減のために、一体化成型の可能性について模索を
開始しており、鋼板メーカーに対する品質要求は、一部
の用途についてはますます厳しくなってきている。この
ため、現状の深絞り用鋼板では対応しきれないケースが
増加しつつあり、さらに成形加工性に優れた鋼板の開発
が強く望まれている。On the other hand, the automobile industry has begun to explore the possibility of integrated molding in order to simplify the manufacturing process and reduce the number of parts, and the quality requirements for steel sheet manufacturers are increasing for some applications. It's getting tougher. For this reason, the number of cases that cannot be handled by the current deep drawing steel sheets is increasing, and there is a strong desire to develop steel sheets with even better formability.
この発明の目的は、前記めっき鋼板に要求される諸性質
を考慮し、今までの深絞り用鋼板では対処できなかった
ような用途に対応できる高い成形加工性を有するメツキ
鋼板の製造方法を提供するものである。The purpose of the present invention is to provide a method for manufacturing a plated steel plate that has high formability and can be used in applications that could not be handled with conventional deep drawing steel plates, taking into account the various properties required of the plated steel plate. It is something to do.
課題を解決するための手段
本発明者らは、上記目的を達成すべく、多くの研究や試
作を行った。その結果、高い成形加工性を得ると共に、
製造上の問題を極力押え、操業条件が多少変動しても、
ある程度の特性を有するめっき鋼板を安定して得るには
、極低炭素鋼に少量のＴｉとＮｂを複合添加し、かつ熱
間圧延後に、６５０〜９００℃で一次焼鈍を行い、鋼板
中のＴｉ１Ｎｂによる窒化物、炭化物、硫化物などの析
出状態や結晶粒およびその集合組織を調整し、冷間圧延
後の焼鈍時の結晶粒成長性の向上などにより、焼鈍後の
組織を成形性に好ましい組織とする。また、Ｓｉ、Ｍｎ
の添加量を所定値に抑制し、めっき時のぬれ性を良好に
することによって、目的とする成形特性を有するめっき
鋼板が得られることを究明し、この発明を完成した。Means for Solving the Problems The present inventors conducted a lot of research and trial production in order to achieve the above object. As a result, high moldability is obtained, and
We minimize manufacturing problems and, even if operating conditions change slightly,
In order to stably obtain a plated steel sheet with certain properties, a small amount of Ti and Nb are added in combination to ultra-low carbon steel, and after hot rolling, primary annealing is performed at 650 to 900°C to remove Ti1Nb in the steel sheet. By adjusting the precipitation state of nitrides, carbides, sulfides, etc., crystal grains and their texture, and improving crystal grain growth during annealing after cold rolling, the structure after annealing is made favorable for formability. shall be. Also, Si, Mn
It was discovered that a plated steel sheet having the desired forming characteristics could be obtained by controlling the amount of addition to a predetermined value and improving the wettability during plating, and the present invention was completed.
すなわちこの発明は、重量％で、
Ｃ： ０．００３０％以下、 Ｓｉ：０．０４％以下
、Ｍｎ ： ０．２０％以下、 Ｐ ： ０．
０３０％以下、Ｓ ： ０．００８％以下、
Ａｌ：０．０２〜０．１０％、
Ｎ ： ０．００３０％以下、 Ｔ ｉ ： ０．
０６０％以下、Ｎｂ ： ０．００５〜０．０３０％
、かつ、ＴｉとＮｂの添加量が、
Ｔｉ／４８ ＋Ｎｂ／９３≧Ｃ／１２＋Ｎ／１４＋Ｓ／
３２を満足し、残部がＦｅおよび不可避的不純物
からなる鋼片を、熱間圧延したのち６５０〜９００℃で
一次焼鈍を行い、ついで圧下率５０％以上で冷間圧延し
たのち、再結晶温度〜９００℃以下で連続焼鈍を行い、
冷却過程で溶融亜鉛めっきを施すのである。That is, this invention has the following properties in terms of weight percentage: C: 0.0030% or less, Si: 0.04% or less, Mn: 0.20% or less, P: 0.
030% or less, S: 0.008% or less, Al: 0.02 to 0.10%, N: 0.0030% or less, Ti: 0.
060% or less, Nb: 0.005-0.030%
, and the amounts of Ti and Nb added are Ti/48 +Nb/93≧C/12+N/14+S/
32, and the remainder consists of Fe and unavoidable impurities, is hot rolled, then primary annealed at 650 to 900°C, then cold rolled at a reduction rate of 50% or more, and then recrystallized at ~ Continuously annealed at 900℃ or less,
Hot-dip galvanizing is applied during the cooling process.
また、重量％で、
Ｃ： ０．００２０％以下、 Ｓｉ：０．０２％以下
、Ｍｎ ： ０．１５％以下、 Ｐ ： ０．
０１０％以下、Ｓ ： ０．００５％以下、
Ａ１：０．０２〜０．０８％、
Ｎ： ０．００２０％以下、 Ｔ ｉ ： ０．０
４０％以下、Ｎｂ ： ０．００５〜０．０３０％、
かつ、ＴｉとＮｂの添加量が、
Ｔｉ／４８ ＋Ｎｂ／９３≧Ｃ／１２＋ Ｎ／１４＋
Ｓ／３２を満足し、残部がＦｅおよび不可避的不純物
からなる鋼片を、熱間圧延したのち ６５０〜９００℃
で一次焼鈍を行い、ついで圧下率５０％以上で冷間圧延
したのち、再結晶温度〜９００℃で連続焼鈍を行い、冷
却過程で溶融亜鉛めっきを施すのである。In addition, in weight %, C: 0.0020% or less, Si: 0.02% or less, Mn: 0.15% or less, P: 0.
010% or less, S: 0.005% or less, A1: 0.02-0.08%, N: 0.0020% or less, T i: 0.0
40% or less, Nb: 0.005-0.030%,
And the amounts of Ti and Nb added are Ti/48 +Nb/93≧C/12+ N/14+
A steel billet that satisfies S/32 and the remainder consists of Fe and unavoidable impurities is hot-rolled at 650-900°C.
After primary annealing is carried out at a temperature of 50% or more, followed by cold rolling at a reduction rate of 50% or more, continuous annealing is carried out at a recrystallization temperature of 900° C. and hot-dip galvanizing is performed during the cooling process.
作 用
つぎにこの発明において鋼の成分組成および製造工程を
限定した理由を詳述する。なお、以降の鋼の成分組成の
％は、特に断わりのないかぎり重量％を示す。Function Next, the reason why the chemical composition and manufacturing process of the steel are limited in this invention will be explained in detail. Note that the percentages in the following steel compositions indicate weight percentages unless otherwise specified.
（１）鋼の成分組成範囲
Ｃは、通常鋼中に固溶Ｃあるいはセメンタイトとして存
在し、ＴｉやＮｂを添加している場合、には、ＴｉＣ，
ＮｂＣなどの析出物としても存在する。これらは成形性
や深絞り性に対しては有害であり、少ないほど素材とし
ては有利である。さらに固溶Ｃが残存すると時効劣化を
起こすので、固溶Ｃが残らないようにＴｉ、Ｎｂを添加
する必要がある。(1) The chemical composition range C of steel usually exists as solid solution C or cementite in steel, and when Ti or Nb is added, TiC,
It also exists as precipitates such as NbC. These are harmful to formability and deep drawability, and the smaller the amount, the more advantageous it is for the material. Furthermore, if solid solution C remains, aging will occur, so it is necessary to add Ti and Nb so that no solid solution C remains.
このため、Ｃが多いと必要となるＴｉ、Ｎｂの添加量が
増加し、合金コストが上昇する。また、Ｔｉ添加量が多
い場合は連続鋳造においてノズルの閉塞や溶損が発生し
易くなる。For this reason, if there is a large amount of C, the amounts of Ti and Nb required to be added will increase, leading to an increase in alloy cost. Furthermore, if the amount of Ti added is large, nozzle clogging and melting damage are likely to occur during continuous casting.
このような理由により、Ｃの含有量を ０．００３０％
以下、好ましくは０．００２０％以下とする。For these reasons, the C content was reduced to 0.0030%.
The content is preferably 0.0020% or less.
Ｓｉは、一般には強度を高めるために添加する元素であ
るが、溶融亜鉛めっき鋼板製造の場合には、連続焼鈍中
にＳｉが鋼板の表面に濃化し、溶融亜鉛との付着張力を
著しく低下させ、めっき付着性が悪化して不めっきを起
こしやすくなる（ある研究によるとＳｉが０．１０％で
亜鉛との付着張力が零となり、０．１０％を超えると付
着張力が負となって、亜鉛をはじくようになるという報
告がある）。Si is generally an element added to increase strength, but in the case of manufacturing hot-dip galvanized steel sheets, Si concentrates on the surface of the steel sheet during continuous annealing, significantly reducing the adhesion tension with molten zinc. , plating adhesion deteriorates and non-plating is more likely to occur (according to one study, when Si is 0.10%, the adhesion tension with zinc becomes zero, and when it exceeds 0.10%, the adhesion tension becomes negative, There are reports that it becomes a zinc repellent).
特に材料特性に対しては、連続焼鈍ラインに均熱帯を有
し、ある程度の均熱時間がある方が特性の安定性の上で
も有利である。しかし、均熱時間を長くするほどＳｉの
表面濃化が促進されるので、良好な溶融めっき鋼板を製
造するには、Ｓｉが０．０４％以下であることが必要で
、好ましくは０．０２％以。In particular, with regard to material properties, it is advantageous to have a soaking zone in the continuous annealing line and a certain amount of soaking time in terms of property stability. However, the longer the soaking time, the more surface concentration of Si is promoted, so in order to produce good hot-dip galvanized steel sheets, it is necessary that the Si content be 0.04% or less, preferably 0.02%. % or more.
下である。It's below.
Ｍｎは、基本的には鋼中に不可避的不純物として含まれ
るＳを固定し１．Ｓによる脆化を防止すると共に、Ｓｉ
と同様に鋼板の強度を高めるために有効な元素である。Mn basically fixes S, which is included as an unavoidable impurity in steel, and 1. In addition to preventing embrittlement due to S,
Similarly, it is an effective element for increasing the strength of steel sheets.
しかし極低Ｃ−Ｔｉ添加鋼の場合は、かなりのＳがＴｉ
と結合すると考えてよいので、それほど多くは必要ない
。むしろ、Ｍｎの添加量が増大すると、強度の上昇と共
に伸びが低下し、特にｒ値が低下する傾向が大きい。さ
らにＭｎは、Ｓｉと同様、表面濃化によるめっき性１〇
−
ヘの悪影響があるので、Ｍｎは０．２０％以下、好まし
くは０．１５％以下とする。However, in the case of ultra-low C-Ti added steel, a considerable amount of S is added to Ti.
You can think of it as combining with , so you don't need that many. On the contrary, when the amount of Mn added increases, the strength increases and the elongation decreases, and in particular, the r value tends to decrease. Furthermore, like Si, Mn has an adverse effect on plating properties due to surface concentration, so Mn is set to 0.20% or less, preferably 0.15% or less.
Ｐは、Ｓｉ、Ｍｎと同様に鋼板の強度を高める作用の大
きな元素である。しかしＰは、伸びやｒ値に対してＭｎ
と比較してその影響が少ないが、やはり悪化させる作用
がある。特に０．１０％以上のＰは、鋼板の伸びのを著
しく劣化させるばかりでなく、粒界に偏析することで粒
界劣化を引起こし、耐二次加工脆性が悪化する。しかし
ながら、高い成形性を有する鋼板を製造するには、Ｐの
添加量を０．１０％未満とするだけでは不十分で、０．
０３０％以下にする必要がある。このため、Ｐは０．０
３０％以下、好ましくは０．０２０％以下とする。P, like Si and Mn, is an element that has a large effect on increasing the strength of the steel plate. However, P has a negative effect on elongation and r value.
Although the effect is less compared to that of the previous example, it still has an aggravating effect. Particularly, P of 0.10% or more not only significantly deteriorates the elongation of the steel sheet, but also segregates at grain boundaries, causing grain boundary deterioration and worsening secondary work brittleness. However, in order to produce a steel plate with high formability, it is insufficient to reduce the amount of P added to less than 0.10%;
It is necessary to keep it below 0.030%. Therefore, P is 0.0
The content should be 30% or less, preferably 0.020% or less.
Ｓは、鋼中に不可避的不純物として含有され、鋼板の延
性やｒ値を低下させる。また、極低Ｃ−Ｔｉ鋼の場合は
、熱間圧延前、例えばスラブとして加熱中にＴｉと結合
するので、その分子ｉ添加量を増加させる必要があり、
合金コストが上昇する。しかも、析出したＴｉＳが微細
の場合は、延性に対する悪影響があり、逆に粗大の場合
は、へゲ欠陥の原因となる。このためこの発明ではＭ
ｎ 。S is contained in steel as an unavoidable impurity and reduces the ductility and r value of the steel plate. In addition, in the case of ultra-low C-Ti steel, it is bonded with Ti before hot rolling, for example during heating as a slab, so it is necessary to increase the amount of molecule i added.
Alloy cost increases. Furthermore, if the precipitated TiS is fine, it has an adverse effect on ductility, and if it is coarse, it causes hege defects. Therefore, in this invention, M
n.
Ｔｉ添加量とのバランスも考慮し、Ｓは０．００８％以
下、好ましくは０．００５％以下とする。Considering the balance with the amount of Ti added, S is set to 0.008% or less, preferably 0.005% or less.
ＡＩは、鋼の脱酸のために添加され、Ｔｉが酸化して失
われ添加歩留りが低下したり、延性を悪化させる鋼中非
金属介在物（酸化物）の生成を抑制する働きをする。ま
た、常温時効の原因となり、延性にも悪影響をおよぼす
ＮをＡＩＮとして固定する作用を有する。しかしこの発
明においては、Ｎ含有量を低くしているし、Ｔｉを添加
してＮを固定しているので、多く添加する必要がない。AI is added to deoxidize steel, and serves to suppress the formation of nonmetallic inclusions (oxides) in steel that cause Ti to be oxidized and lost, reducing the addition yield and deteriorating ductility. It also has the effect of fixing N, which causes aging at room temperature and has an adverse effect on ductility, as AIN. However, in this invention, the N content is low and Ti is added to fix N, so there is no need to add a large amount.
また、ＡＩ添加量を多くすると合金コストが上昇し、Ａ
Ｉ＝Ｏａなどの介在物が増加して延性が劣化する。In addition, increasing the amount of AI added increases the alloy cost, and
Inclusions such as I=Oa increase and ductility deteriorates.
このため、Ａｌは０．０２０〜ｏ、 ｉｏｏ％、好まし
くは０、０２０〜０．０８０％とする。For this reason, Al should be 0.020 to 0.00%, preferably 0.020 to 0.080%.
Ｎは、Ｓと同様に鋼中に不可避的不純物として含有され
、固溶Ｎは鋼板の延性やｒ値を低下させる。また、常温
時効を起こしてストレッチャーストレインの原因となる
。極低Ｃ−Ｔｉ鋼の場合は、ＮはＳと同様に熱間圧延前
に大部分がＴｉＮとして固定されるので、Ｎ含有量が多
くなると必要なＴｉ量が増加して合金コストの上昇を招
く。また、析出しなＴｉＮがＥｌやｒ値に悪影響を与え
、析出物が粗大の場合にはヘゲ欠陥の原因となることも
ある。Like S, N is contained in steel as an unavoidable impurity, and solid solution N reduces the ductility and r value of the steel sheet. It also causes aging at room temperature and causes stretcher strain. In the case of ultra-low C-Ti steel, like S, most of the N is fixed as TiN before hot rolling, so as the N content increases, the required amount of Ti increases, leading to an increase in alloy cost. invite Further, precipitated TiN has a negative effect on El and r values, and if the precipitates are coarse, they may cause hege defects.
このため、Ｎは０．００３０％以下、好ましくは０、０
０２０％以下である。Therefore, N is 0.0030% or less, preferably 0,0%
0.020% or less.
Ｔｉは、延性やｒ値に悪影響を及ぼす鋼中のＮ。Ti is N in steel, which has a negative effect on ductility and r-value.
ＳＳＣを析出物として固定することによって除去し、成
形性を向上させるために添加する。ＴｉはＡ１、Ｎｂ、
Ｍｎなどに先立って熱間圧延前にＮやＳを固定し、しか
るのちＣを固定する。このため、Ｔｉが添加されていな
いと、Ｎが微細なＡＩＮに、またＳは微細なＭｎＳとな
り、いずれも延性に悪影響を与える。SSC is removed by fixing it as a precipitate and is added to improve formability. Ti is A1, Nb,
Prior to hot rolling, N and S are fixed prior to Mn, and then C is fixed. For this reason, if Ti is not added, N becomes fine AIN and S becomes fine MnS, both of which have an adverse effect on ductility.
したがってＴｉの添加量は、固定するＮＳＳ。Therefore, the amount of Ti added is fixed at NSS.
Ｃの含有量およびＮｂ添加量を考慮しなければならず、
最低添加量はＮ、Ｓ、ＣおよびＮｂ量によって変動する
。The content of C and the amount of Nb added must be considered,
The minimum addition amount varies depending on the amount of N, S, C, and Nb.
一方、Ｔｉの添加量は、Ｎ、Ｓ、Ｃを固定するよりも若
干多めであれば問題ない。しかし著しく過剰になると、
その効果が頭打ちとなり、合金コストの上昇を招くばか
りでなく、連続鋳造時の溶鋼注入中にノズル閉塞や溶損
を起こし易くなる。On the other hand, there is no problem as long as the amount of Ti added is slightly larger than that of fixing N, S, and C. However, if it becomes extremely excessive,
This effect reaches a ceiling, which not only causes an increase in alloy cost, but also makes it easier for nozzle blockage and melting damage to occur during injection of molten steel during continuous casting.
また、非金属介在物であるＴｉｅｓが生成して大きな表
面疵（ノロ噛み）が発生し易くなる。そのため、Ｔｉ添
加量は、０．０６０％以下とする。In addition, Ties, which are non-metallic inclusions, are generated and large surface scratches (slag bites) are likely to occur. Therefore, the amount of Ti added is 0.060% or less.
Ｎｂは、どちらかといえばＴｉよりも優先的にＣを固定
してＮｂＣとして析出し、あるいは鋼中に固溶Ｎｂとし
て存在することによって、熱間圧延後の一次焼鈍時や冷
間圧延後の二次焼鈍時、結晶粒が異常成長するのを防止
して結晶粒を整粒化し、延性を向上させるために添加す
る。Ｎｂを添加することによって高成形性が確保できる
と共に、鋼板加工時の肌荒れを防止することができる。Nb fixes C more preferentially than Ti and precipitates as NbC, or exists as solid solution Nb in the steel, so that it can be absorbed during primary annealing after hot rolling or after cold rolling. It is added to prevent abnormal growth of crystal grains during secondary annealing, to regularize the crystal grains, and to improve ductility. By adding Nb, high formability can be ensured, and roughening of the surface during processing of the steel plate can be prevented.
しかしながら、Ｎｂ含有量が０．００５％未満の場合は
、所望の効果が得られない。逆に０．０３０％を超えて
含有させても、その効果は頭打ちとなり、合金コストの
上昇を招くばかりでなく、ＮｂＣ量が増加して再結晶温
度が上昇し、鋼が硬化して反＝１４−
対に成形性の劣化が起こり易くなる。However, if the Nb content is less than 0.005%, the desired effect cannot be obtained. On the other hand, even if the content exceeds 0.030%, the effect will reach a plateau and not only will the alloy cost rise, but the NbC content will increase, the recrystallization temperature will rise, the steel will harden, and the anti-= 14- Deterioration of moldability tends to occur in pairs.
このため、Ｎｂ含有量は、０．００５〜０．０３０％と
する。Therefore, the Nb content is set to 0.005 to 0.030%.
ＴｉとＮｂの各添加量については、前記したとおりであ
るが、ＴｉおよびＮｂは、鋼中のＮ、Ｓ。The amounts of Ti and Nb added are as described above, but Ti and Nb are the same as N and S in the steel.
Ｃを析出物として固定するために添加するのであるから
、Ｎ、ＳＳＣの含有量をまったく無視することはできな
い。このため、所定の添加量範囲で、しかも、次の式を
満足させる必要がある。Since C is added to fix C as a precipitate, the contents of N and SSC cannot be ignored at all. Therefore, it is necessary to satisfy the following formula within a predetermined addition amount range.
Ｔｉ／４８ ＋Ｎｂ／９３≧Ｃ／１２＋Ｎ／１４＋Ｓ／
３２・・（１）また、ＴｉとＮｂの添加量は、上記（１
）式を満足させる範囲内で、できるだけ少ない方が望ま
しν）。Ti/48 +Nb/93≧C/12+N/14+S/
32...(1) Also, the amounts of Ti and Nb added are the same as (1) above.
) is preferably as small as possible within the range that satisfies the formula ν).
前記元素の他に０．Ｃｒ、Ｃｕなども不可避的に鋼中に
含まれる元素である。この発明におし１ては、これらの
元素の含有量もできるだけ少なり１方が好ましい。でき
ればＯ： ０．００５％未満、Ｃｒ：０．１％未満、Ｃ
ｕ：０．１％未満を目安として規制するのが望ましい。In addition to the above elements, 0. Cr, Cu, etc. are also elements that are inevitably included in steel. According to the present invention, it is preferable that the content of these elements be as small as possible. Preferably O: less than 0.005%, Cr: less than 0.1%, C
u: It is desirable to regulate it at less than 0.1%.
また、二次加工脆性が特に重要な場合には、少量のＢな
どを添加することができる。Furthermore, if secondary processing embrittlement is particularly important, a small amount of B or the like can be added.
（２）熱間圧延後の一次焼鈍条件
通常の冷延鋼板製造プロセスは、熱間圧延で得た熱延鋼
板を酸洗などにより脱スケールしたのち、そのまま冷間
圧延するのが普通である。(2) Conditions for primary annealing after hot rolling In a normal cold rolled steel sheet production process, a hot rolled steel sheet obtained by hot rolling is usually descaled by pickling or the like, and then cold rolled as is.
しかるにこの発明においては、熱間圧延後の熱延鋼板を
冷間圧延前に高温で焼鈍（以下「−次焼鈍」という）す
ることを特徴としている。However, the present invention is characterized in that the hot rolled steel sheet after hot rolling is annealed at a high temperature (hereinafter referred to as "secondary annealing") before cold rolling.
この−次焼鈍は、コイルのままのバッチ焼鈍あるいはオ
ーブンコイルの連続焼鈍のいずれでもよい。また、この
−次焼鈍は、脱スケール前の熱延鋼板、あるいは脱スケ
ール後の熱延鋼板のいずれかで実施すればよい。This secondary annealing may be either batch annealing of the coil as it is or continuous annealing of the oven coil. Further, this secondary annealing may be performed on either the hot-rolled steel sheet before descaling or the hot-rolled steel sheet after descaling.
なお、この発明においては、鋼板のＣ含有量が３０ｐｐ
ｍ以下と低く、また、Ｔｉ、Ｎｂなどにより固定されて
いるので、スケールによる脱炭は考慮する必要はない。In addition, in this invention, the C content of the steel plate is 30 pp.
It is low, less than m, and is fixed by Ti, Nb, etc., so there is no need to consider decarburization due to scale.
上記−次焼鈍は、冷間圧延前の鋼板中のＴｉＮ、Ｔｉ５
ＳＴｉＣ，ＮｂＣ等の析出状態や結晶粒およびその集合
組織を調整する。また、冷間圧延したのちの焼鈍（以下
「二次焼鈍」という）後の組織を高成形性を得るのに好
ましい組織とするための準備工程として重要である。The above-mentioned second annealing is performed using TiN and Ti5 in the steel sheet before cold rolling.
Adjust the precipitation state, crystal grains, and texture of STiC, NbC, etc. It is also important as a preparatory step for making the structure after cold rolling and then annealing (hereinafter referred to as "secondary annealing") into a structure preferable for obtaining high formability.
すなわち、熱延鋼板は、−次焼鈍することによってＴｉ
などにより固定されていなかった固溶Ｎ１Ｓ、ＣがＴｉ
Ｎ、ＴｉＳ、ＴｉＣとしてほとんど析出し、これと同時
に、粗大化までいかない程度で凝集する。また、Ｎｂは
、Ｔｉと同様ＮｂＣとしてＣの析出を十分ならしめ、引
続き行なわれる冷間圧延−二次焼鈍後の細粒化や高ｒ値
化を確実なものとする。In other words, the hot-rolled steel sheet is subjected to secondary annealing to reduce Ti.
The solid solution N1S and C that were not fixed by Ti
Most of it precipitates as N, TiS, and TiC, and at the same time, it aggregates to the extent that it does not become coarse. Further, like Ti, Nb serves as NbC to ensure sufficient precipitation of C, thereby ensuring grain refinement and high r-value after subsequent cold rolling and secondary annealing.
つまりＴｉＮ、Ｔｉ５１ＴｉＣＳＮｂＣの析出が不十分
な場合は、鋼中に固溶Ｃ，Ｎ、Ｓが残留して延性を低下
させる。このほか、冷間圧延−二次焼鈍後の鋼板の結晶
組織や集合組織が高成形性に適したものに、十分生成、
成長が行なわれず、高ｒ値、高Ｅｌが得られない。In other words, if precipitation of TiN and Ti51TiCSNbC is insufficient, solid solution C, N, and S remain in the steel, reducing ductility. In addition, the crystal structure and texture of the steel sheet after cold rolling and secondary annealing are sufficiently formed to be suitable for high formability.
No growth occurs, and high r value and high El cannot be obtained.
このため、−次焼鈍の温度および時間は、鋼の成分およ
び要求される製品の成形性の程度により調整される。し
かし、−次焼鈍の温度が６５０℃未満では、前記した効
果が十分得られない。また、９００℃を超えると著しい
結晶粒粗大化が発生し、それを原因とする製品の肌荒れ
を生じる。したがって、−次焼鈍温度は、６５０〜９０
０℃、好ましくは７００〜８００℃である。Therefore, the temperature and time of the secondary annealing are adjusted depending on the composition of the steel and the required degree of formability of the product. However, if the temperature of the secondary annealing is less than 650°C, the above-mentioned effects cannot be sufficiently obtained. Moreover, when the temperature exceeds 900°C, significant coarsening of crystal grains occurs, which causes rough skin of the product. Therefore, the second annealing temperature is 650 to 90
0°C, preferably 700-800°C.
一次焼鈍をバッチ焼鈍で行う場合は、８００℃以上の高
温であれば均熱時間が短くてすむが、焼付きや局部的ダ
レイングロースを起こす恐れが大きくなる。このため、
好ましくは８００℃未満で、最低２時間以上、より好ま
しくは５時間以上の長時間焼鈍を行うのが望ましい。確
実かつ安定して要求される成形性を得るには、１０時間
以上焼鈍することが望ましい。When the primary annealing is performed by batch annealing, the soaking time can be shortened at a high temperature of 800° C. or higher, but there is a greater risk of seizure or local sagging growth. For this reason,
It is desirable to perform annealing at a temperature of preferably less than 800°C for a long time of at least 2 hours, more preferably 5 hours or more. In order to reliably and stably obtain the required formability, it is desirable to perform annealing for 10 hours or more.
一次焼鈍を連続焼鈍で行う場合は、８００℃以上の高温
が必要で、かつ均熱時間は最低１分以上、好ましくは２
分以上焼鈍することが望ましい。When primary annealing is performed by continuous annealing, a high temperature of 800°C or higher is required, and the soaking time is at least 1 minute, preferably 2 minutes.
It is desirable to anneal for at least 1 minute.
なお、−次焼鈍を行った鋼板は、−次焼鈍を行なわなか
った鋼板に比較し、二次焼鈍の条件を同一にすると、当
然特性が優れている。このことは二次焼鈍条件が悪くて
も、同様の特性レベルを得ることができるということで
、二次焼鈍条件が多少変動しても、安定した特性レベル
の鋼板を製造できるという利点となる。Incidentally, a steel plate subjected to secondary annealing naturally has better properties than a steel plate not subjected to secondary annealing when the secondary annealing conditions are the same. This means that even if the secondary annealing conditions are bad, the same level of properties can be obtained, which is an advantage that a steel plate with stable properties can be manufactured even if the secondary annealing conditions vary somewhat.
（３）その後の製造条件
一次焼鈍された鋼板は、引続き冷間圧延−二次焼鈍され
る。この冷間圧延−二次焼鈍の方法は、従来から実施さ
れている超深絞り用鋼板の製造条件、例えば圧下率５０
％以上での冷間圧延、再結晶温度以上での二次焼鈍でよ
い。また、その後の溶融亜鉛めっき処理は、一般に実施
されている方法で行なえばよい。(3) Subsequent manufacturing conditions The primarily annealed steel plate is subsequently cold rolled and secondly annealed. This cold rolling-secondary annealing method is performed under conventional manufacturing conditions for ultra-deep drawing steel sheets, such as a rolling reduction of 50.
% or higher, or secondary annealing at a temperature higher than the recrystallization temperature. Further, the subsequent hot-dip galvanizing treatment may be performed by a commonly used method.
ただし、二次焼鈍温度は、高すぎると結晶粒の著しい粗
大化が起こるので、上限を９００℃とする。However, if the secondary annealing temperature is too high, significant coarsening of crystal grains will occur, so the upper limit is set to 900°C.
しかし７５０〜８８０℃が望ましい。However, a temperature of 750 to 880°C is desirable.
溶融亜鉛めっきされた鋼板は、その後、必要に応じて５
００〜６００℃で１０秒程度の合金化処理、あるいは調
質圧延（スキンパス）を実施することもできる。The hot-dip galvanized steel sheet is then optionally coated with
It is also possible to perform alloying treatment at 00 to 600° C. for about 10 seconds or skin pass rolling.
なお、合金化処理溶融亜鉛めっき鋼板は、合金化処理さ
れためっき皮膜が硬質であるためその影響を受け、同強
度レベルの冷延鋼板に比較し、Ｅｌやｒ値が低くなる傾
向がある。その低下の程度は、合金化処理条件あるいは
亜鉛めっき付着量によって異なるが、Ｅｌで２〜３％、
ｒ値で０．２〜０．３である。Note that alloyed hot-dip galvanized steel sheets are affected by the hardness of the alloyed plating film, and tend to have lower El and r values compared to cold-rolled steel sheets of the same strength level. The degree of reduction varies depending on the alloying treatment conditions or the amount of zinc plating deposited, but it is 2 to 3% for El.
The r value is 0.2 to 0.3.
実 施 例
実施例１
第１表に示す成分以外は、Ｆｅと不可避的不純物からな
る鋼を転炉で溶製し、真空脱ガス処理したのち、常法に
したがい連続鋳造してスラブとした。このスラブを仕上
げ温度１２００℃、巻取り温度約６９０℃、板厚４．０
ｍｍの条件で熱間圧延を行った。EXAMPLES Example 1 A steel consisting of Fe and unavoidable impurities other than those shown in Table 1 was melted in a converter, subjected to vacuum degassing treatment, and then continuously cast into a slab according to a conventional method. The finishing temperature of this slab is 1200℃, the winding temperature is about 690℃, and the plate thickness is 4.0℃.
Hot rolling was performed under the condition of mm.
次いで熱延鋼板は、酸洗処理したのち、第１表に示すと
おり種々の温度でバッチ焼鈍（−次焼鈍）して徐々に冷
却した。Next, the hot-rolled steel sheets were pickled, then batch annealed (-second annealing) at various temperatures as shown in Table 1, and gradually cooled.
一次焼鈍したこれらの熱延鋼板は、ついで圧下率８０％
、板厚０．８ｍｍの条件で冷間圧延を行い、冷延鋼板を
製造した。得られた冷延鋼板は、加熱温度７５０〜８５
０℃で６０秒前後連続焼鈍（二次焼鈍）し、約４６０℃
まで冷却して連続溶融亜鉛めっきラインで、約４６０℃
の亜鉛めっき浴中に浸漬して溶融亜鉛めっきを施した。These primary annealed hot rolled steel sheets are then subjected to a rolling reduction of 80%.
, cold rolling was performed under the conditions of a plate thickness of 0.8 mm to produce a cold rolled steel plate. The obtained cold-rolled steel sheet was heated at a heating temperature of 750 to 85
Continuously annealed at 0℃ for around 60 seconds (secondary annealing), then heated to about 460℃
Cooled to approximately 460°C in a continuous hot-dip galvanizing line.
Hot-dip galvanizing was performed by immersing the steel in a galvanizing bath.
次いで合金化炉で５００〜６００℃に１０秒間保持して
合金化処理し、さらに伸び率０．４〜０．８％の調質圧
延を実施し、合金化処理溶融亜鉛めっき鋼板を製造した
。Next, alloying was performed by maintaining the temperature at 500 to 600° C. for 10 seconds in an alloying furnace, and temper rolling was further performed at an elongation rate of 0.4 to 0.8% to produce an alloyed hot-dip galvanized steel sheet.
得られた合金化処理溶融亜鉛めっき鋼板のそれぞれから
し方向にＪＩＳ Ｓ号試験片を切出し、機械的特性を測
定した。その結果を第１表に示す。JIS No. S test pieces were cut out in the mustard direction of each of the obtained alloyed hot-dip galvanized steel sheets, and the mechanical properties were measured. The results are shown in Table 1.
以下余白
なお、成分組成あるいは製造条件がこの発明の範囲外の
鋼板および他種鋼板を比較例として示す。In the following margin, steel sheets whose compositions or manufacturing conditions are outside the scope of the present invention and steel sheets of other types are shown as comparative examples.
第１表に示すとおり、この発明の合金化処理溶融亜鉛め
っき鋼板は、比較例の合金化処理溶融亜鉛めっき鋼板に
比較し、ＹＰが低く、Ｅｌ、ｒ値が高く、高成形性を有
しており、自動車用材料、特に難成形で著しい成形性を
要求されるような部品の材料として、非常に適している
。As shown in Table 1, the alloyed galvanized steel sheet of the present invention has a lower YP, higher El and r values, and higher formability than the alloyed galvanized steel sheet of the comparative example. Therefore, it is very suitable as a material for automobiles, especially for parts that are difficult to form and require remarkable formability.
実施例２ 第２表に示す成分組成の異なるＡ、Ｂ２種類の。Example 2 Two types, A and B, with different component compositions shown in Table 2.
鋼を転炉で溶製し、真空脱ガス処理したのち、常法にし
たがい連続鋳造してスラブとした。このスラブを仕上げ
温度１２００℃、巻取り温度約６９０℃、板厚４．０ｍ
ｍの条件で熱間圧延を行った。次いで熱延鋼板は、酸洗
処理したのち２分割し、鋼Ａの一方は７３０℃で１０時
間、鋼Ｂの一方は７８０℃で１０時間バッチ焼鈍（−次
焼鈍）して徐々に冷却した。鋼Ａ、Ｂの他方は一次焼鈍
しなかった。そしてこれらの熱延鋼板は、ついで圧下率
８０％、板厚０．８ｍｍの条件で冷間圧延を行い、冷延
鋼板を製造した。Steel was melted in a converter, vacuum degassed, and then continuously cast into slabs using conventional methods. Finishing temperature of this slab is 1200℃, winding temperature is about 690℃, plate thickness is 4.0m
Hot rolling was performed under the conditions of m. The hot rolled steel sheet was then pickled and then divided into two parts, one of which was steel A, was batch annealed (second annealing) at 730°C for 10 hours, and one part of steel B was batch annealed (secondary annealing) at 780°C for 10 hours, and then gradually cooled. The other of steels A and B was not primarily annealed. These hot-rolled steel sheets were then cold-rolled at a rolling reduction of 80% and a thickness of 0.8 mm to produce cold-rolled steel sheets.
得られた冷延鋼板は、第２表に示すとおり種々の温度で
約６０秒のラボ焼鈍（二次焼鈍）を施した。The obtained cold rolled steel sheets were subjected to laboratory annealing (secondary annealing) at various temperatures for about 60 seconds as shown in Table 2.
得られた冷延鋼板のそれぞれからＬ方向にＪＩＳＳ号試
験片を切出し、機械的特性を測定した。その結果を第２
表に示す。JISS No. test pieces were cut out from each of the obtained cold-rolled steel sheets in the L direction, and their mechanical properties were measured. The result is the second
Shown in the table.
なお、試験では、できるだけ特性に誤差の入る要因を少
なくするため、亜鉛めっきはせず、調質圧延も施さずに
実施した。In addition, the test was conducted without galvanizing or temper rolling in order to minimize the factors that would cause errors in the characteristics.
以下余白
第２表に示すとおり、この発明の特徴である熱間圧延後
に一次焼鈍を実施した鋼板は、−次焼鈍を実施しなかっ
た鋼板に比較し、同様の二次焼鈍条件では、良好な機械
的特性を得ることができる。As shown in Table 2 below, steel sheets subjected to primary annealing after hot rolling, which is a feature of the present invention, have better performance under similar secondary annealing conditions compared to steel sheets not subjected to secondary annealing. Mechanical properties can be obtained.
また、−次焼鈍を実施した鋼板は、同レベルの特性を二
次焼鈍温度が低くても得ることができる。Moreover, the steel plate subjected to secondary annealing can obtain the same level of properties even if the secondary annealing temperature is low.
このことは、二次焼鈍条件が変動しても、安定して良好
な特性を得ることができることを示すものである。This shows that even if the secondary annealing conditions vary, it is possible to stably obtain good properties.
なお、二次焼鈍条件が９１０℃×６０秒の場合は、はと
んどが異常粒成長肌荒れが発生し、Ｅｌとｒ値が焼鈍温
度が高いにもかかわらず逆に低下している。Note that when the secondary annealing conditions are 910° C. x 60 seconds, abnormal grain growth occurs in most cases, and the El and r values decrease despite the high annealing temperature.
発明の効果
この発明方法によれば、自動車用材料、特に難成形で著
しく高い成形性を要求されるような部品の材料として、
非常に適している合金化処理溶融亜鉛めっき鋼板を安定
して製造することができる。Effects of the Invention According to the method of the invention, the material for automobiles, especially for parts that are difficult to form and require extremely high formability, can be used as
A highly suitable alloyed galvanized steel sheet can be stably produced.
Claims (1)
：０．２０％以下、Ｐ：０．０３０％以下、Ｓ：０．０
０８％以下、 Ａｌ：０．０２〜０．１０％、 Ｎ：０．００３０％以下、Ｔｉ：０．０６０％以下、Ｎ
ｂ：０．００５〜０．０３０％、 かつ、ＴｉとＮｂの添加量が、 Ｔｉ／４８＋Ｎｂ／９３≧Ｃ／１２＋Ｎ／１４＋Ｓ／３
２を満足し、残部がＦｅおよび不可避的不純物 からなる鋼片を、熱間圧延したのち６５０〜９００℃で
一次焼鈍を行い、ついで圧下率５０％以上で冷間圧延し
たのち、再結晶温度〜９００℃以下で連続焼鈍を行い、
冷却過程で溶融亜鉛めっきを施すことを特徴とする高成
形性を有する溶融亜鉛めっき鋼板の製造方法。 ２ 重量％で、 Ｃ：０．００２０％以下、Ｓｉ：０．０２％以下、Ｍｎ
：０．１５％以下、Ｐ：０．０１０％以下、Ｓ：０．０
０５％以下、 Ａｌ：０．０２〜０．０８％、 Ｎ：０．００２０％以下、Ｔｉ：０．０４０％以下、Ｎ
ｂ：０．００５〜０．０３０％、 かつ、ＴｉとＮｂの添加量が、 Ｔｉ／４８＋Ｎｂ／９３≧Ｃ／１２＋Ｎ／１４＋Ｓ／３
２を満足し、残部がＦｅおよび不可避的不純物 からなる鋼片を、熱間圧延したのち６５０〜９００℃で
一次焼鈍を行い、ついで圧下率５０％以上で冷間圧延し
たのち、再結晶温度〜９００℃で連続焼鈍を行い、冷却
過程で溶融亜鉛めっきを施すことを特徴とする高成形性
を有する溶融亜鉛めっき鋼板の製造方法。[Claims] 1% by weight, C: 0.0030% or less, Si: 0.04% or less, Mn
: 0.20% or less, P: 0.030% or less, S: 0.0
08% or less, Al: 0.02 to 0.10%, N: 0.0030% or less, Ti: 0.060% or less, N
b: 0.005 to 0.030%, and the amount of Ti and Nb added is Ti/48+Nb/93≧C/12+N/14+S/3
2, and the remainder consists of Fe and unavoidable impurities, is hot rolled, then primary annealed at 650 to 900°C, then cold rolled at a reduction rate of 50% or more, and then recrystallized at ~ Continuous annealing is performed at 900℃ or less,
A method for producing a hot-dip galvanized steel sheet with high formability, characterized by applying hot-dip galvanizing during a cooling process. 2% by weight, C: 0.0020% or less, Si: 0.02% or less, Mn
: 0.15% or less, P: 0.010% or less, S: 0.0
05% or less, Al: 0.02 to 0.08%, N: 0.0020% or less, Ti: 0.040% or less, N
b: 0.005 to 0.030%, and the amount of Ti and Nb added is Ti/48+Nb/93≧C/12+N/14+S/3
2, and the remainder consists of Fe and unavoidable impurities, is hot rolled, then primary annealed at 650 to 900°C, then cold rolled at a reduction rate of 50% or more, and then recrystallized at ~ A method for producing a hot-dip galvanized steel sheet with high formability, which comprises continuous annealing at 900°C and hot-dip galvanizing during the cooling process.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11786190A JPH0413816A (en) | 1990-05-07 | 1990-05-07 | Production of galvanized steel sheet having high moldability |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11786190A JPH0413816A (en) | 1990-05-07 | 1990-05-07 | Production of galvanized steel sheet having high moldability |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0413816A true JPH0413816A (en) | 1992-01-17 |
Family
ID=14722115
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP11786190A Pending JPH0413816A (en) | 1990-05-07 | 1990-05-07 | Production of galvanized steel sheet having high moldability |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0413816A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2011052268A1 (en) * | 2009-10-26 | 2011-05-05 | 新日本製鐵株式会社 | Alloyed hot-dip galvanized steel sheet having excellent formability and post-adhesion detachment resistance, and manufacturing method therefor |
| WO2011052269A1 (en) * | 2009-10-26 | 2011-05-05 | 新日本製鐵株式会社 | Alloyed hot-dip galvanized steel sheet and manufacturing method therefor |
| JP2015063729A (en) * | 2013-09-25 | 2015-04-09 | 新日鐵住金株式会社 | 440 MPa CLASS HIGH STRENGTH ALLOYED HOT-DIP GALVANIZED STEEL SHEET EXCELLENT IN DEEP DRAWABILITY AND PRODUCTION METHOD THEREOF |
-
1990
- 1990-05-07 JP JP11786190A patent/JPH0413816A/en active Pending
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| WO2011052268A1 (en) * | 2009-10-26 | 2011-05-05 | 新日本製鐵株式会社 | Alloyed hot-dip galvanized steel sheet having excellent formability and post-adhesion detachment resistance, and manufacturing method therefor |
| WO2011052269A1 (en) * | 2009-10-26 | 2011-05-05 | 新日本製鐵株式会社 | Alloyed hot-dip galvanized steel sheet and manufacturing method therefor |
| CN102575330A (en) * | 2009-10-26 | 2012-07-11 | 新日本制铁株式会社 | Alloyed hot-dip galvanized steel sheet and manufacturing method therefor |
| CN102666903A (en) * | 2009-10-26 | 2012-09-12 | 新日本制铁株式会社 | Alloyed hot-dip galvanized steel sheet having excellent formability and post-adhesion detachment resistance, and manufacturing method therefor |
| JP5146607B2 (en) * | 2009-10-26 | 2013-02-20 | 新日鐵住金株式会社 | Alloyed hot-dip galvanized steel sheet and manufacturing method thereof |
| JP5168417B2 (en) * | 2009-10-26 | 2013-03-21 | 新日鐵住金株式会社 | Alloyed hot-dip galvanized steel sheet excellent in formability and peel resistance after adhesion and method for producing the same |
| US9040168B2 (en) | 2009-10-26 | 2015-05-26 | Nippon Steel & Sumitomo Metal Corporation | Galvannealed steel sheet having excellent formability and exfoliation resistance after adhesion and production method thereof |
| US9133536B2 (en) | 2009-10-26 | 2015-09-15 | Nippon Steel & Sumitomo Metal Corporation | Galvannealed steel sheet and producing method thereof |
| EP2495347A4 (en) * | 2009-10-26 | 2016-10-26 | Nippon Steel & Sumitomo Metal Corp | Alloyed hot-dip galvanized steel sheet and manufacturing method therefor |
| US9903022B2 (en) | 2009-10-26 | 2018-02-27 | Nippon Steel 7 Sumitomo Metal Corporation | Production method of galvannealed steel sheet having excellent formability and exfoliation resistance after adhesion |
| JP2015063729A (en) * | 2013-09-25 | 2015-04-09 | 新日鐵住金株式会社 | 440 MPa CLASS HIGH STRENGTH ALLOYED HOT-DIP GALVANIZED STEEL SHEET EXCELLENT IN DEEP DRAWABILITY AND PRODUCTION METHOD THEREOF |
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