TW201207126A - High strength steel sheet having excellent formability and method for manufacturing the same - Google Patents

High strength steel sheet having excellent formability and method for manufacturing the same Download PDF

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TW201207126A
TW201207126A TW100122843A TW100122843A TW201207126A TW 201207126 A TW201207126 A TW 201207126A TW 100122843 A TW100122843 A TW 100122843A TW 100122843 A TW100122843 A TW 100122843A TW 201207126 A TW201207126 A TW 201207126A
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steel sheet
phase
workability
strength steel
hot
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TW100122843A
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TWI431124B (en
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Kenji Kawamura
Hidetaka Kawabe
Kazuhiro Seto
Noriyuki Katayama
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Jfe Steel Corp
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    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
    • C21D8/0263—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment following hot rolling
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
    • C21D8/0226—Hot rolling
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/46—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for sheet metals
    • 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
    • C22C38/005—Ferrous alloys, e.g. steel alloys containing rare earths, i.e. Sc, Y, Lanthanides
    • 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
    • C22C38/08—Ferrous alloys, e.g. steel alloys containing nickel
    • 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
    • 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
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • 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
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/54—Ferrous alloys, e.g. steel alloys containing chromium with nickel with boron
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/005—Ferrite
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/009—Pearlite

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Heat Treatment Of Sheet Steel (AREA)

Abstract

Provided are a high-strength steel sheet which is thin and has excellent processability and a process for producing the steel sheet. The process comprises: a hot rolling step in which a steel material having a composition containing, in terms of mass%, 0.08-0.15% C, 0.5-1.5% Si, 0.5-1.5% Mn, 0.01-0.1% Al, and up to 0.005% N is hot-rolled to obtain a hot-rolled sheet; annealing in which the hot-rolled sheet is pickled and then held for 5-400 seconds in the first temperature range of from the Ac1 transformation point to the Ac3 transformation point in a continuous annealing line, without being cold-rolled; and cooling in which the sheet is cooled from the first temperature range to 700 C at an average cooling rate of 5 C/sec or higher and held for 30-400 seconds in the second temperature range of from 700 C to 400 C. Thus, a structure comprising a ferrite phase and a second phase comprising pearlite can be obtained, the ferrite phase and the pearlite accounting for 75-90% by area and 10-25% by area, respectively, of the whole structure. The pearlite accounts for 70% by area or more of the whole second phase and has an average grain diameter of 5 μ m or less. As a result, a high-strength steel sheet which has a strength (TS) as high as 540 MPa or above, excellent stretchability and stretch flangeability, and excellent processability is obtained.

Description

201207126 六、發明說明： 【發明所屬技術領域】 本發明係關於適合作爲：被要求具有優異的加工性（ 伸長凸緣性）之汽車零件的強度構件等來使用的高強度鋼 板及其製造方法。 【先前技術】 近年來基於地球環保的觀點，提昇汽車的燃油效率已 經成爲一個重要的技術課題。因此，將所使用的材料予以 高強度化，以謀求構件厚度的薄型化，進而使得車體本身 的輕量化的做法非常普遍地被採用。作爲所使用的材料， 特別是被要求拉伸強度：540MPa以上的高強度鋼板。但 是，鋼板的高強度化將會導致加工性的降低，所以乃期望 能夠有一種具有優異的加工性的高強度鋼板，尤其是針對 於厚度較薄的鋼板（薄鋼板），這種期望很高。 針對於這種期望，有人提出各種的技術方案，例如： 具有由肥粒鐵相與麻田散鐵相所組成的雙相組織的雙相鋼 板（DP鋼板）、具有包含肥粒鐵相與麻田散鐵相以及變韌鐵 相之複合組織的鋼板等等的各種複合組織鋼板。 例如：專利文獻1所揭示的高強度冷軋鋼板的製造方 法，是將具有含 C: 0.08 〜0.30%、Si: 0.1〜2.5%、Μη: 0.5〜2.5 %、Ρ : 0.0 1〜0.1 5 %的組成分之冷軋鋼板，利用 Acl點以上的溫度進行再結晶退火，接下來，從Arl點至 600°C之溫度範圍爲止，進行強制空氣冷卻之後，再以100 201207126 °c /秒以上的冷卻速度進行急速冷卻，而作成由肥粒鐵相 與低溫變態生成相所組成的複合組織，然後，以根據特定 的關係式所求出的低溫變態生成相硬度Hv(L)相對於肥粒 鐵硬度Ην(α )的比値，Hv(L)/HV(a )符合1.5〜3.5的範圍 之方式，利用3 50〜600 °C範圍的溫度來執行過時效處理， 而可獲得具有優異的局部延伸性的高強度冷乳鋼板。專利 文獻1所揭示的技術，係提高淬火開始溫度以提高低溫變 態生成相的體積率，然後，以3 50〜600°C的溫度執行過時 效處理，讓C晶析於肥粒鐵中，並且讓低溫變態生成相軟 化，使得Hv(L)/Hv( α )的比値變小，藉以改善局部延伸性 〇 又，專利文獻2所揭示的具有優異的耐腐蝕性之低降 伏比高張力熱軋鋼板的製造方法，係將含有C: 0.02〜 0.25%、Si: 2.0 % 以下、Μη: 1.6 〜3.5%、Ρ: 〇.〇3 〜0.20 % 、S: 0.02%以下、Cu: 0.05 〜2.0%、sol.Α1: 0.005 〜 0.100%、N : 0.008 %以下的鋼胚板予以熱間輥軋而做成熱 軋鋼帶捲，實施酸洗後，將該熱軋鋼帶捲在連續退火處理 線以720〜95〇°C的溫度執行退火處理，藉此而獲得具有優 異的耐腐蝕性之低降伏比高張力熱軋鋼板。根據專利文獻 2所揭示的技術，係可製造出：既可維持低降伏比、高延 性以及良好的擴孔性，而且優異之具有複合組織的高張力 熱軋鋼板。 又，專利文獻3所揭示的「強度與伸長凸緣性之兩者 間的平衡優異的高強度冷軋鋼板」，係具有包含C: 0.03 -6- 201207126 〜0.1 7 %、S i : 1 · 0 % 以下、Μη : Ο · 3 〜2.0 % ' P : 〇 〇 i 〇 % 以 下、S: 0.010%以下、Al: 0.005〜0.06%，並且符合 C(%)>(3/40)xMn的關係之組成分，以及以變韌鐵或波來 鐵爲主的第二相與肥粒鐵相所成的組織，並且符合（第二 相的維氏硬度）/(肥粒鐵相的維氏硬度）之比値係爲達K6 的關係之強度與伸長凸緣性之兩者間的平衡優異的高強度 冷軋鋼板。專利文獻3所揭示的高強度冷軋鋼板，係將具 有上述組成分的鋼（鋼胚）予以熱間輥軋之後，以65 0。(：以 下的溫度進行捲取，實施酸洗之後，進行冷間輥軋，緊接 著’利用點以上至（A3點+50°C )以下的溫度來進行均熱 處理’接下來，在75 0〜650°C的範圍間以20。(：/秒以下的 速度慢慢地冷卻直到變成溫度T!爲止，接下來，從T i至 5 00°C爲止，係執行以20°C /秒以上的速度來進行冷卻之退 火處理’緊接著，以500〜250°C的溫度進行過時效處理而 獲得的。 [先前技術文獻] [專利文獻] [專利文獻1 ]日本特開昭6 3 - 2 9 3 1 2 1號公報 [專利文獻2 ]日本特開平〇 5 _ i丨2 8 3 2號公報 [專利文獻3]日本特開平10_60593號公報 【發明內容】 [發明所欲解決之課題] 然而，專利文獻1所揭示的技術中所存在的問題是 201207126 不僅需要使用到：於再結晶退火後可執行急速冷卻（淬火 處理）的連續退火設備，而且爲了要抑制因高溫的過時效 處理所導致的急劇的強度降低，必須添加大量的合金元素 〇 又，專利文獻2所揭示的技術中所存在的問題是，雖 然必須將大量的P、Cu予以複合地添加，但含有大量的 Cu的話，將會降低熱間加工性，而且含有大量的P的話 ，將會導致鋼的脆化。此外，P在鋼中偏析出來的傾向很 強，這種偏析出來的P不僅會降低鋼板的伸長凸緣性，而 且也會引起焊接部的脆化。 又，專利文獻3所揭示的高強度冷軋鋼板，雖然具有 優異的伸長凸緣性，但是其所存在的問題是，當其強度是 540MP a以上的高強度的情況下，伸長率未達26%，並無 法確保足以維持所期望的優異加工性的程度之充分的伸長 率。 本發明之目的係在於解決這些先前技術的問題，而提 供：板厚爲1.0〜1.8mm程度之薄板型的加工性優異之高 強度鋼板及其製造方法。此外，此處所稱的「高強度」係 指：拉伸強度（TS)爲540MPa以上、更好是具有590MPa 以上的強度者而言，此外，所稱的「優異的加工性」係指 :伸長率（E1)爲30%以上（使用日本工業規格JIS 5號試驗 片的情況下），依據日本鋼鐵聯盟制定的規格JFST 1001-1 996的擴孔試驗時的擴孔率（λ )爲80%以上的情況而言。 201207126 [用以解決問題之手段] 本發明人等爲了達成上述目的，乃針對於組成分與細 微組織對強度以及加工性的影響，努力地進行了硏究。其 結果，獲得了一種創見，就是，對於將合金元素量調整在 恰當的範圍的熱軋鋼板，並不實施冷間輥軋，而是藉由實 施了加熱到適當的雙相溫度域的退火處理以及適當的冷卻 處理，可製成以肥粒鐵相爲主相，並且是以細微的波來鐵 來做爲第二相的主體之組織（金屬組織），藉此，可確保所 期望的高強度，並且可大幅地提升加工性，進而可獲得兼 具有所期望的伸長率以及所期望的擴孔率之加工性優異之 高強度鋼板。 有關於爲何對於熱軋鋼板，省略實施冷間輥軋而是藉 由直接實施適當的退火處理，就可以大幅地提升加工性的 理由之詳細的機轉，迄今尙未明確，但是本發明人等係推 測爲下列的理由。 對於熱軋鋼板不實施冷間輥軋，只加熱至雙相溫度域 的退火處理的話，在進行退火加熱時，只會產生（^相―7 相的變態而已，並不會產生新的再結晶。這種情況下，只 有在C濃度較高的地方優先地產生α相—r相的變態而已 ’不僅可獲得更均勻的組織，而且擴散速度較快的C，在 進行退火處理時，α相與r相會被再分配直到變成平衡組 成分爲止。因此，可以抑制在粒界上之薄片狀的碳化鐵的 析出’特別是對於提升伸長凸緣性可發揮有利的作用。另 一方面’如果是對於熱軋鋼板實施了冷間輥軋之後，又實 -9 - 201207126 施退火處理的話，在進行退火加熱時，再結晶現象與α相 —r相的變態現象將會互相競合，因此很容易變成不均勻 的組織，難以期待可大幅地提升加工性。 本發明係基於這種創見，再進一步加以檢討而完成的 。亦即，本發明的要旨如下所述。 (1) —種加工性優異之高強度鋼板，其特徵爲： 具有由：以質量％計，含有C : 0.0 8〜0.1 5 %、S i : 0.5 〜1 . 5 %、Μ η : 0.5 〜1. 5 %、P : 0.1 % 以下、S : 0 · 0 1 % 以下 、Α1 : 0.01〜0.1%、Ν : 0.005%以下，其餘部分是Fe以及 不可避免的雜質所組成的成分，以及 由作爲主相的肥粒鐵相、與至少含有波來鐵的第二相 所組成的金屬組織； 以相對於整個金屬組織的面積率計，前述肥粒鐵相佔 75〜90%，前述波來鐵佔10〜25%，且該波來鐵的平均粒 徑是5μπι以下，並且前述波來鐵相對於前述第二相的全部 面積的面積率係7 0 %以上。 (2) 如前述（1)所述之加工性優異之高強度鋼板，其中 ，在前述成分中又含有：從Cr、V、Mo之中所選出的一 種或兩種以上，而上述Cr、V、Mo的含量，以質量％計， Cr : 0.05 〜0.5%、V : 0.005 〜0.2%、Mo : 0.005 〜0,2%。 (3) 如前述（1)或（2)所述之加工性優異之高強度鋼板 ，其中’在前述成分中又含有：從Ti、Nb之中所選出的 —種或兩種，而上述Ti、Nb的含量，以質量％計，Ti: 0.0 1 〜0 · 1 %、N b : 0 . 〇 1 〜0.1 %。 -10- 201207126[Technical Field] The present invention relates to a high-strength steel sheet suitable for use as a strength member or the like of an automobile part which is required to have excellent workability (elongation flangeability) and a method for producing the same. [Prior Art] In recent years, based on the perspective of global environmental protection, improving the fuel efficiency of automobiles has become an important technical issue. Therefore, it is very common to increase the strength of the material to reduce the thickness of the member, and to make the weight of the vehicle body itself very popular. As the material to be used, in particular, a high-strength steel sheet having a tensile strength of 540 MPa or more is required. However, the high strength of the steel sheet will result in a decrease in workability, so it is desirable to have a high-strength steel sheet having excellent workability, especially for a thin steel sheet (thin steel sheet), which is highly desirable. . In response to this expectation, various technical proposals have been proposed, such as: a dual-phase steel plate (DP steel plate) having a two-phase structure composed of a ferrite grain iron phase and a granulated iron phase, having an iron phase containing a fat grain and a granule phase Various composite structural steel sheets such as steel sheets and steel sheets of a composite structure of a tough iron phase. For example, the method for producing a high-strength cold-rolled steel sheet disclosed in Patent Document 1 has a C content of 0.08 to 0.30%, Si: 0.1 to 2.5%, Μη: 0.5 to 2.5%, and Ρ: 0.0 1 to 0.1 5 %. The cold-rolled steel sheet of the composition is recrystallized and annealed at a temperature higher than the Acl point, and then, after forced air cooling from the temperature range of Arl to 600 ° C, the temperature is 100 201207126 ° c /sec or more. The cooling rate is rapidly cooled, and a composite structure composed of the ferrite grain iron phase and the low temperature metamorphic phase is formed, and then the phase hardness Hv(L) is generated relative to the ferrite iron by the low temperature metamorphism determined according to the specific relationship. The hardness Ην(α ) ratio 値, Hv(L)/HV(a ) conforms to the range of 1.5 to 3.5, and the overaging treatment is performed at a temperature in the range of 3 50 to 600 ° C, and an excellent local portion can be obtained. Extensible high strength cold milk steel sheet. The technique disclosed in Patent Document 1 is to increase the quenching start temperature to increase the volume fraction of the low temperature metamorphic phase, and then perform an aging treatment at a temperature of 3 50 to 600 ° C to crystallize C in the ferrite iron, and Softening the low-temperature metamorphic phase, so that the specific enthalpy of Hv(L)/Hv(α) becomes smaller, thereby improving the local extensibility, and the low-ratio to high-tensile heat with excellent corrosion resistance disclosed in Patent Document 2 The method for producing a rolled steel sheet contains C: 0.02 to 0.25%, Si: 2.0% or less, Μη: 1.6 to 3.5%, Ρ: 〇.〇3 to 0.20%, S: 0.02% or less, Cu: 0.05 to 2.0. %, sol.Α1: 0.005 to 0.100%, N: 0.008% or less, the steel blank is hot rolled to form a hot rolled steel coil, and after pickling, the hot rolled steel strip is wound on a continuous annealing line. The annealing treatment is performed at a temperature of 720 to 95 ° C, whereby a low-ratio high-tensile hot-rolled steel sheet having excellent corrosion resistance is obtained. According to the technique disclosed in Patent Document 2, it is possible to produce a high-tensile hot-rolled steel sheet having a composite structure which can maintain a low drop-to-volt ratio, high ductility, and good hole expandability. Moreover, the "high-strength cold-rolled steel sheet excellent in the balance between the strength and the elongation flangeability" disclosed in Patent Document 3 has C: 0.03 -6 - 201207126 to 0.1 7 %, S i : 1 · 0% or less, Μη : Ο · 3 to 2.0 % ' P : 〇〇i 〇% or less, S: 0.010% or less, Al: 0.005 to 0.06%, and conform to C(%)>(3/40)xMn The composition of the relationship, and the structure of the second phase and the ferrite iron phase, which is mainly composed of toughened iron or wave iron, and conforms to (Vickers hardness of the second phase) / (Vickers of the ferrite phase) The ratio of the hardness is a high-strength cold-rolled steel sheet excellent in the balance between the strength of the K6 relationship and the elongation flangeability. In the high-strength cold-rolled steel sheet disclosed in Patent Document 3, the steel (steel blank) having the above composition is subjected to hot rolling, and is 65 0. (: The following temperature is taken up, and after pickling is performed, cold rolling is performed, and then the heat treatment is performed at a temperature equal to or lower than (A3 point + 50 ° C). Next, at 75 0~ Between 650 ° C and 20 ° C / sec, the temperature is slowly cooled to a temperature of 20 ° or less until the temperature becomes T!, and then from T i to 500 ° C, the temperature is 20 ° C / sec or more. Annealing treatment for cooling at a temperature is carried out immediately after the aging treatment at a temperature of 500 to 250 ° C. [Prior Art Document] [Patent Literature] [Patent Document 1] Japanese Patent Laid-Open No. 6 3 - 2 9 [Patent Document 2] Japanese Patent Laid-Open Publication No. JP-A No. Hei. No. Hei. No. Hei. The problem in the technique disclosed in Patent Document 1 is that 201207126 requires not only continuous annealing equipment which can perform rapid cooling (quenching treatment) after recrystallization annealing, but also in order to suppress overaging treatment due to high temperature. Sharp intensity reduction, must be added The problem of the alloy element is that the technique disclosed in Patent Document 2 has a problem that although a large amount of P and Cu must be added in combination, if a large amount of Cu is contained, the inter-heat processability is lowered and the content is contained. A large amount of P will lead to embrittlement of steel. In addition, P has a strong tendency to segregate in steel. This segregation of P not only reduces the elongational flangeability of the steel sheet, but also causes brittleness of the welded portion. Further, the high-strength cold-rolled steel sheet disclosed in Patent Document 3 has excellent elongation flangeability, but has a problem that when the strength is high strength of 540 MP a or more, the elongation is not Up to 26%, and sufficient elongation sufficient to maintain the desired excellent workability is not ensured. The object of the present invention is to solve the problems of the prior art, and to provide a sheet type having a thickness of about 1.0 to 1.8 mm. The high-strength steel sheet excellent in workability and the method for producing the same. The term "high strength" as used herein means a tensile strength (TS) of 540 MPa or more, more preferably 590 MPa or more. In addition, the term "excellent workability" means that the elongation (E1) is 30% or more (in the case of using the Japanese Industrial Standard JIS No. 5 test piece), and the specifications are based on the Japan Iron and Steel Federation. In the case of the hole expansion ratio (λ) of the hole expansion test of JFST 1001-1 996, it is 80% or more. 201207126 [Means for Solving the Problem] The present inventors have focused on the composition and the like in order to achieve the above object. The effect of the fine structure on the strength and the workability has been diligently studied. As a result, it has been found that the hot-rolled steel sheet in which the amount of the alloying element is adjusted to an appropriate range is not subjected to cold rolling. Rather, by performing annealing treatment heated to an appropriate two-phase temperature domain and appropriate cooling treatment, the iron phase of the ferrite phase can be made into a main phase, and the fine wave iron is used as the second phase. By the structure (metal structure) of the main body, the desired high strength can be ensured, and the workability can be greatly improved, and the workability superior to the desired elongation and the desired hole expansion ratio can be obtained. Strength steel sheet. Regarding the hot-rolled steel sheet, the detailed operation of the reason why the workability can be greatly improved by directly performing the appropriate annealing treatment by omitting the cold rolling is not clear, but the present inventors have The reason is presumed to be the following. In the case where the hot-rolled steel sheet is not subjected to cold rolling and is heated only to the annealing treatment in the two-phase temperature range, only the (phase--7 phase metamorphosis) is generated when the annealing is performed, and no new recrystallization occurs. In this case, only the metamorphism of the α phase-r phase is preferentially generated in the place where the C concentration is high, and 'not only a more uniform structure but also a C having a faster diffusion rate, and the α phase is subjected to the annealing treatment. The r phase is redistributed until it becomes a balanced component. Therefore, it is possible to suppress the precipitation of the flake-shaped iron carbide on the grain boundary, which is particularly advantageous for improving the elongation flangeability. After the cold rolling of the hot-rolled steel sheet is carried out, and the annealing treatment is carried out, the recrystallization phenomenon and the α phase-r phase metamorphism will compete with each other during the annealing heating, so it is easy to The structure becomes uneven, and it is difficult to expect that the workability can be greatly improved. The present invention has been completed based on such a concept and further reviewed. That is, the gist of the present invention is as follows. (1) A high-strength steel sheet excellent in workability, comprising: C: 0.0 8 to 0.1 5 % by mass %, S i : 0.5 〜1 . 5 %, Μ η : 0.5 〜 1. 5 %, P: 0.1% or less, S: 0 · 0 1 % or less, Α1: 0.01 to 0.1%, Ν: 0.005% or less, and the rest is composed of Fe and unavoidable impurities, and a ferrogranular iron phase of the main phase and a metal phase composed of a second phase containing at least Boron iron; the ferrite phase accounts for 75 to 90% of the ferrite phase relative to the entire metal structure, and the aforementioned Boron iron 10% to 25%, and the average particle diameter of the ferrite is 5 μm or less, and the area ratio of the entire area of the ferrite to the second phase is 70% or more. (2) As described above (1) The high-strength steel sheet excellent in workability, wherein the component further contains one or more selected from the group consisting of Cr, V, and Mo, and the content of the Cr, V, and Mo, by mass% Cr: 0.05 to 0.5%, V: 0.005 to 0.2%, and Mo: 0.005 to 0, 2%. (3) Excellent workability as described in the above (1) or (2) a high-strength steel sheet in which 'in the foregoing composition, further contains: one or two selected from Ti and Nb, and the content of Ti and Nb, in mass%, Ti: 0.0 1 〜0 · 1 % , N b : 0 . 〇1 ～0.1 %. -10- 201207126

(4) 如前述（1)至（3)中任一項所述之加工性優異之高 強度鋼板’其中’在前述成分中又含有：以質量％計，B :0.0003 〜0.0050%° (5) 如前述（1)至（4)中任一項所述之加工性優異之高 強度鋼板，其中，在前述成分中又含有：從Ni' cu之中 所選出的一種或兩種，而上述Ni、Cu的含量，以質量％ 計，Ni: 0.05 〜0.5 %、Cu: 0.05 〜0.5 %。 (6) 如前述（1)至（5 )中任一項所述之加工性優異之高 強度鋼板’其中，在前述成分中又含有：從Ca、rem之 中所選出的一種或兩種，而上述Ca、REM的含量，以質 量％計，Ca: 0.001 〜0.005 %、REM: 0.001 〜0.005 %。 (7) —種加工性優異之高強度鋼板的製造方法，其特 徵爲： 對於具有由：以質量％計，含有C : 0.08〜0.15%、Si :0.5 〜1.5%、Μη: 0.5 〜1.5%、P: 0.1 %以下、S: 0.01% 以下、Α1 ·· 0.01〜0· 1 %、Ν : 0.005%以下，其餘部分是Fe 以及不可避免的雜質所組成的成分的鋼素材， 實施下列的熱軋工序以及連續退火工序， 該熱軋工序，係進行熱軋以製作成熱軋鋼板： 該連續退火工序，係在對於前述熱軋鋼板進行酸洗之 後，將該熱軋鋼板在連續退火處理線上，在AC!變態點〜 AC3變態點的第一溫度範圍內保持5〜400秒的退火處理， 以及在該退火處理之後，執行：自前述第一溫度範圍起迄 700 °C爲止，以5 °C /秒以上的平均冷卻速度進行冷卻，並 201207126 且將在700。(：〜400°C爲止的第二溫度範圍內的滞留時間選 定爲30〜400秒的冷卻處理。 (8) 如前述（7)所述之加工性優異之高強度鋼板的製造 方法，其中，前述熱軋工序，係將前述鋼素材加熱到1100 〜1280 °C的範圍的溫度之後，進行熱軋結束時溫度被設爲 870〜95〇t的熱軋以製作成熱軋鋼板，在該熱軋結束之後 ，對於該熱軋鋼板進行捲取，而此時的捲取溫度被設爲 350 〜720 〇C ° (9) 如前述（7)或（8)所述之加工性優異之高強度鋼板 的製造方法，其中，在前述第二溫度範圍之中，在700〜 5 50°C的溫度範圍的冷卻時間係被選定爲1 0秒以上。 (10) 如前述（7)至（9)中任一項所述之加工性優異之高 強度鋼板的製造方法，其中，在前述成分中又含有：從Cr 、V、Mo之中所選出的一種或兩種以上，而上述Cr、V、(4) The high-strength steel sheet excellent in the workability as described in any one of the above (1) to (3), wherein 'in the above-mentioned components, further contains, in mass%, B: 0.0003 to 0.0050% (5) The high-strength steel sheet excellent in workability according to any one of the above (1) to (4), wherein the above-mentioned component further contains one or two selected from Ni' cu, and the above The content of Ni and Cu is, in terms of mass%, Ni: 0.05 to 0.5%, and Cu: 0.05 to 0.5%. (6) The high-strength steel sheet excellent in workability as described in any one of the above (1) to (5), wherein the above-mentioned component further contains one or two selected from Ca and rem, The content of Ca and REM described above is, in mass%, Ca: 0.001 to 0.005%, and REM: 0.001 to 0.005%. (7) A method for producing a high-strength steel sheet excellent in workability, comprising: C: 0.08 to 0.15% by mass, Si: 0.5 to 1.5%, Μη: 0.5 to 1.5% by mass% , P: 0.1% or less, S: 0.01% or less, Α1 ··0.01~0·1 %, Ν: 0.005% or less, and the rest is a steel material composed of Fe and unavoidable impurities, and the following heat is applied. a rolling step and a continuous annealing step of hot rolling to produce a hot-rolled steel sheet: the continuous annealing step of picking the hot-rolled steel sheet on a continuous annealing line after pickling the hot-rolled steel sheet And maintaining an annealing treatment for 5 to 400 seconds in the first temperature range of the AC! metamorphosis point to the AC3 transformation point, and after the annealing treatment, performing: from the first temperature range up to 700 °C, to 5 ° The average cooling rate above C / sec is cooled and is 201207126 and will be at 700. (The retention time in the second temperature range up to 400 ° C is selected to be a cooling treatment of 30 to 400 seconds. (8) The method for producing a high-strength steel sheet having excellent workability as described in the above (7), wherein In the hot rolling step, the steel material is heated to a temperature in the range of 1100 to 1280 ° C, and hot rolling is performed at a temperature of 870 to 95 〇t at the end of hot rolling to prepare a hot rolled steel sheet. After the completion of the rolling, the hot-rolled steel sheet is wound up, and the coiling temperature at this time is set to 350 to 720 ° C ° (9) The high strength excellent in workability as described in the above (7) or (8) In the method of producing a steel sheet, in the second temperature range, the cooling time in a temperature range of 700 to 550 ° C is selected to be 10 seconds or longer. (10) As described in the above (7) to (9) The method for producing a high-strength steel sheet having excellent workability according to any one of the above, wherein the component further comprises one or more selected from the group consisting of Cr, V, and Mo, and the Cr, V, and

Mo的含量，以質量％計，Cr: 0.05〜0.5%、V: 0.005〜 0 · 2 %、Μ 〇 : 0 · 0 0 5 〜0.2 %。 (1 1)如前述（7)至（10)中任一項所述之加工性優異之 高強度鋼板的製造方法’其中，在前述成分中又含有：從 Ti、Nb之中所選出的一種或兩種，而上述Ti、Nb的含量 ，以質量 ％計，Ti : 0.01 〜〇」％、Nb : 0.01 〜0.1%。 (1 2)如前述（7)至（〗丨）項中任—項所述之加工性優異 之高強度鋼板的製造方法，其中，在前述成分中又含有： 以質量 ％計 ’ B: 0.0003 〜0.0050 %。 (13)如前述（7)至（12)中任一項所述之加工性優異之 -12- 201207126 高強度鋼板的製造方法’其中，在前述成分中又含有：從 Ni、Cu之中所選出的一種或兩種，而上述Ni、Cu的含量 ’以質量 ％ 計 ’ N i : 〇 . 〇 5 〜〇. 5 %、c U : 0.0 5 〜0.5 %。 (1 4)如前述（7)至（1 3 )中任一項所述之加工性優異之 高強度鋼板的製造方法，其中，在前述成分中又含有：從 Ca、REM之中所選出的一種或兩種，而上述ca、REM的 含量，以質量％計’€3:〇.〇〇1〜〇.〇〇5%、11丑^1:0.001〜 0.005% » [發明效果] 根據本發明係可很容易且以低廉的價格製造出：拉伸 強度（TS)爲540MPa以上的高強度，並且兼具有伸長率 (E1)爲3 0 %以上的伸長率以及伸長凸緣性（λ )爲8 〇 %以上 的伸長凸緣性之加工性優異之高強度鋼板，可達成對於産 業具有貢獻之特別的效果。又，本發明係可省略冷間輥軋 的工序，所以對於降低製造成本、提升生産性的方面也具 有大幅地助益之效果。此外，尤其是將本發明的鋼板應用 在例如：汽車車體零件的話，對於汽車車體的輕量化具有 很大的貢獻。 【實施方式】 首先，說明限定本發明鋼板的成分之理由。在以下的 說明中，如果沒有特別地註明的話，質量％係單純以％來 表示。 -13- 201207126 C : 0.0 8 〜0 · 1 5 % C係對於增加鋼板的強度有所幫助，並且是有助於讓 組織形成爲：由肥粒鐵相以及肥粒鐵相以外的第二相所成 的複合組織的元素，在本發明中，爲了確保所期望的拉伸 強度爲540MPa以上的高強度，必須含有0.08%以上。另 —方面，如果含量是超過0.1 5 %的話，則會降低點焊的焊 接性，而且也會降低延性等的加工性。因此，乃將C的含 量限定在〇.〇8〜0.15 %的範圍。最好是0.10〜0.15%。 S i : 0.5 〜1 . 5 %The content of Mo, in terms of mass%, Cr: 0.05 to 0.5%, V: 0.005 to 0 · 2 %, Μ 〇 : 0 · 0 0 5 to 0.2%. (1) The method for producing a high-strength steel sheet having excellent workability as described in any one of the above-mentioned items (7) to (10), further comprising: one selected from the group consisting of Ti and Nb Or two, and the content of the above Ti and Nb is, in mass%, Ti: 0.01 to 〇"%, and Nb: 0.01 to 0.1%. (1) The method for producing a high-strength steel sheet having excellent workability as described in any one of the above items (7) to (7), wherein the component further contains: % by mass 'B: 0.0003 ~0.0050%. (13) A method for producing a high-strength steel sheet of -12 to 201207126, which is excellent in workability according to any one of the above-mentioned items (7) to (12), wherein the component contains: from Ni and Cu. One or two of the selected ones, and the content of Ni and Cu described above is % by mass % 〇 〇 5 〇 5 5 %, c U : 0.0 5 〜 0.5 %. The method for producing a high-strength steel sheet having excellent workability according to any one of the above-mentioned items, wherein the component further comprises: selected from Ca and REM. One or two, and the content of ca and REM described above is in mass % '€3:〇.〇〇1~〇.〇〇5%, 11 ugly^1:0.001~0.005% » [Invention effect] According to this The invention can be easily and inexpensively manufactured with a tensile strength (TS) of 540 MPa or more, and an elongation (E1) of more than 30% and an elongational flangeability (λ). In the high-strength steel sheet having an excellent stretchability of 8 % or more, it is possible to achieve a special effect that contributes to the industry. Further, in the present invention, the step of cold rolling can be omitted, so that it is also advantageous in terms of reducing the manufacturing cost and improving the productivity. Further, in particular, when the steel sheet of the present invention is applied to, for example, an automobile body part, it contributes greatly to the weight reduction of the automobile body. [Embodiment] First, the reason for limiting the components of the steel sheet of the present invention will be described. In the following description, the quality % is simply expressed in % unless otherwise specified. -13- 201207126 C : 0.0 8 〜0 · 1 5 % The C system is helpful for increasing the strength of the steel plate, and it helps to form the structure into a second phase other than the ferrite phase and the ferrite phase. In the present invention, in order to secure a desired high tensile strength of 540 MPa or more, the element of the composite structure to be formed must be contained in an amount of 0.08% or more. On the other hand, if the content is more than 0.15%, the weldability of the spot welding is lowered, and the workability such as ductility is also lowered. Therefore, the content of C is limited to the range of 〇.〇8 to 0.15%. It is preferably 0.10 to 0.15%. S i : 0.5 〜1 . 5 %

Si係可固熔於鋼中而有助於肥粒鐵的強化，並且是對 於提升延性有所幫助的元素，爲了確保所期望的拉伸強度 爲540MPa以上的高強度，必須含有0.5 %以上。另一方面 ，如果含量是1 . 5 %的過量含有的話，則會促進紅色鏽皮 等的發生，不僅會降低鋼板的表面性狀，也會降低化成處 理性。此外，Si的過多含有，將會導致在進行電阻焊接時 之電阻的増加，因而阻礙了電阻焊接性。因此，乃將Si 限定在0.5〜1.5 %的範圍。最好是0.7〜1.2%。 Μ η : 0 · 5 〜1 . 5 % Μη係有助於增加鋼板的強度，並且是對於形成複合 組織之有効的元素，爲了獲得這種效果，必須含有〇 . 5 % 以上。另一方面，如果含量超過1.5%的話，在進行退火 時的冷卻過程中，很容易形成麻田散鐵相，將會導致加工 性特別是伸長凸緣性的降低。因此，乃將Μη限定在0.5 〜1 . 5 %的範圍》最好是〇 · 7〜1. 5 %。 -14- 201207126 P : 0.1 %以下 P係可固熔於鋼中而有助於增加鋼板強度之有效的元 素，但是其在粒界偏析出的傾向很強，會導致粒界的結合 力降低，因而導致加工性的降低，並且會在鋼板表面濃化 ，因而降低了化成處理性、耐腐蝕性等。這種由P所造成 的不良影響，是在其含量超過0.1 %時趨於顯著。因此， 乃將P限定在0.1 %以下。又，爲了規避由P所造成的這 種不良影響，p的含量是在0.1°/。以下，儘量地減少爲宜， 但是如果過度的減少又會導致製造成本的高漲，所以係選 定在0.001%程度以上爲宜。 S : 0.0 1 % 以下 s在鋼中，主要係形成MnS等的硫化物（介在物），會 降低鋼板的加工性，特別是局部的伸長性。此外’硫化物 (介在物）的存在，將會降低焊接性。這種由s所造成的不 良影響，在其含量超過〇.01 %時趨於顯著。因此’乃將s 限定在0.01 %以下。此外’爲了避免這種由s所造成的不 良影響，S的含量是在〇 _ 〇 1 %以下，儘量地減少爲宜，但 是如果過度的減少又會導致製造成本的高漲’所以係選定 在0. 〇 0 01 %程度以上爲宜。 A1 : 0.0 1 〜〇 · 1 % A1係可發揮作爲脫氧劑的作用而是對於提升鋼板的清 浄度所必須的元素’此外’對於提升碳化物形成元素的良 率也可有効地作用。爲了獲得這種效果’其含量必須是 0.01%以上。含量若未達0·01%的話’ si系介在物（將會成 -15- 201207126 爲延遲性破壞的起點）的除去就不夠充分，會增加發生延 遲性破壞的危險性。另一方面，即使含量已經超過〇. 1 % 時，上述的效果已經趨於飽和，無法期待可獲得與其含量 相符合的效果，不僅變得不經濟，而且加工性也會降低， 又會讓發生表面缺陷的傾向増大。因此，乃將 A1限定在 0.01〜0.1 %的範圍。最好是0.01〜0.05 %爲宜。 N : 0.0 0 5 % 以下 N在本發明中係被視爲本質上的有害元素，應該予以 儘量地減少，但是其含量可容許至0.005%爲止。因此， 乃將N限定爲0.005 %以下。又，過度地降低N的含量的 話，將會導致製造成本的高漲，因此係選定在0.0001%程 度以上爲宜。 上述的成分雖然是基本的成分，但是除了這些基本成 分之外，可因應必要又追加含有：例如從Cr: 0.05〜0.5 % 、V: 0.005〜0.2 %、Mo: 0.005〜0.2 %之中所選出的 1種 或2種以上；及/或從Ti: 0.01〜0.1%、Nb: 0.01〜0.1% 之中所選出的1種或2種；及/或從B: 0.0003〜0·0050% 、及/或Ni: 0.05〜0·5 %、Cu: 0.05〜0.5 %之中所選出的1 種或 2 種；及 /或從 Ca: 0.001 〜0.005%、REM: 0.001 〜 0.005 %之中所選出的1種或2種。 從 Cr: 0.05 〜0.5 %、V: 0.005 〜0.2%、Mo: 0.005 〜 0.2%之中所選出的1種或2種以上The Si system can be solid-melted in steel to contribute to the strengthening of the ferrite and iron, and is an element which contributes to the improvement of ductility. In order to secure a high tensile strength of 540 MPa or more, it is necessary to contain 0.5% or more. On the other hand, if the content is excessively contained in 1.5%, the occurrence of red scales and the like is promoted, which not only lowers the surface properties of the steel sheet but also reduces the chemical conversion. Further, excessive inclusion of Si causes an increase in resistance during resistance welding, thereby impeding resistance weldability. Therefore, Si is limited to a range of 0.5 to 1.5%. It is preferably 0.7 to 1.2%. Μ η : 0 · 5 〜1 . 5 % Μη helps to increase the strength of the steel sheet and is an effective element for forming a composite structure. In order to obtain such an effect, it is necessary to contain 〇 5 % or more. On the other hand, if the content exceeds 1.5%, the granule iron phase is easily formed during the cooling during annealing, which results in a decrease in workability, particularly elongation flangeability. Therefore, it is preferable to limit Μη to 0.5 〜1. 5 % of the range ” is preferably 〇 · 7 to 1. 5 %. -14- 201207126 P : 0.1% or less P is an effective element which can be solid-melted in steel and contributes to the strength of the steel sheet. However, the tendency to segregate at the grain boundary is strong, and the binding force at the grain boundary is lowered. As a result, the workability is lowered, and the surface of the steel sheet is concentrated, thereby reducing chemical conversion treatability, corrosion resistance, and the like. This adverse effect caused by P tends to be significant when its content exceeds 0.1%. Therefore, P is limited to 0.1% or less. Further, in order to avoid such adverse effects caused by P, the content of p is 0.1 ° /. In the following, it is preferable to reduce as much as possible, but if the excessive reduction causes the manufacturing cost to rise, it is preferable to select it at a level of 0.001% or more. S : 0.0 1 % or less s In the steel, mainly sulfides (intermediates) such as MnS are formed, which deteriorates the workability of the steel sheet, particularly the local extensibility. In addition, the presence of sulfide (intermediate) will reduce weldability. This kind of adverse effect caused by s tends to be significant when its content exceeds 〇.01%. Therefore, s is limited to 0.01% or less. In addition, in order to avoid such adverse effects caused by s, the content of S is below 〇 〇 % 1%, and it is preferable to reduce it as much as possible, but if excessive reduction leads to high manufacturing cost, it is selected at 0. 〇0 01% or more is appropriate. A1 : 0.0 1 〜 〇 · 1 % The A1 system functions as a deoxidizing agent and is an element necessary for improving the cleanliness of the steel sheet. Further, it can effectively act to improve the yield of the carbide forming element. In order to obtain this effect, the content must be 0.01% or more. If the content is less than 0. 01%, the removal of the si-mediated substance (which will become the starting point of delayed failure in -15-201207126) is insufficient, which increases the risk of delayed damage. On the other hand, even if the content has exceeded 1. 1%, the above effect has become saturated, and it cannot be expected to obtain an effect in accordance with its content, which not only becomes uneconomical, but also reduces workability and causes occurrence. The tendency of surface defects is large. Therefore, A1 is limited to the range of 0.01 to 0.1%. It is preferably 0.01 to 0.05%. N : 0.0 0 5 % or less N is considered to be an essential harmful element in the present invention and should be reduced as much as possible, but its content can be tolerated to 0.005%. Therefore, N is limited to 0.005% or less. Further, if the content of N is excessively lowered, the manufacturing cost will increase, so that it is preferably selected to be 0.0001% or more. Although the above-mentioned components are basic components, in addition to these basic components, they may be additionally included as necessary: for example, from Cr: 0.05 to 0.5%, V: 0.005 to 0.2%, and Mo: 0.005 to 0.2%. 1 or 2 or more; and/or 1 or 2 selected from Ti: 0.01 to 0.1%, Nb: 0.01 to 0.1%; and/or from B: 0.0003 to 0·0050%, and / or Ni: 0.05 to 0.5%, Cu: 0.05 to 0.5% of one or two selected; and / or selected from Ca: 0.001 to 0.005%, REM: 0.001 to 0.005 % 1 or 2 types. One or more selected from the group consisting of Cr: 0.05 to 0.5%, V: 0.005 to 0.2%, and Mo: 0.005 to 0.2%

Cr、V、Mo的任何一種元素都是可增加鋼板的強度， 有助於形成複合組織的元素，可因應必要而選擇性地含有 • 16 - 201207126 1種或2種以上。爲了獲得這種效果，三者的含量係分別 是 Cr ·· 0.05%以上、V ·· 0.005%以上、Mo : 0.005%以上爲 宜。另一方面，如果三者的含量分別是Cr: 0.5%、V : 0.2%、Mo : 0.2%這樣地過量含有的話，在退火處理後的 冷卻處理中，難以生成所期望量的波來鐵，於是就無法確 保所期望的複合組織，伸長凸緣性將會降低，因而加工性 也會降低。因此，如果想要含有的話，係將這三者的含量 分別限定成 Cr: 0.05 〜0.5%、V: 0.005 〜0.2 %、Mo: 0.005〜0.2 %的範圍爲宜。 從Ti :0.01〜0.1%、Nb :0.01〜0.1 %之中所選出的1 種或2種Any one of Cr, V, and Mo is an element which can increase the strength of the steel sheet and contribute to the formation of a composite structure, and can selectively contain one or more of the types of the materials, and can be selectively used. In order to obtain such an effect, the contents of the three are preferably Cr·· 0.05% or more, V·· 0.005% or more, and Mo: 0.005% or more. On the other hand, if the contents of the three are excessively contained such as Cr: 0.5%, V: 0.2%, and Mo: 0.2%, it is difficult to generate a desired amount of ferrite in the cooling treatment after the annealing treatment. Therefore, it is impossible to ensure the desired composite structure, the elongation flangeability is lowered, and the workability is also lowered. Therefore, if it is desired to contain, the contents of the three are preferably limited to Cr: 0.05 to 0.5%, V: 0.005 to 0.2%, and Mo: 0.005 to 0.2%. One or two selected from Ti: 0.01 to 0.1% and Nb: 0.01 to 0.1%

Ti、Nb都是可藉由晶析強化而可增加鋼板強度的元 素，可以因應必要而選擇性地含有1種或2種。爲了獲得 這種效果，兩者的含量分別是 Ti: 0.01%以上、Nb : 0.01%以上爲宜，但是如果兩者的含量分別是Ti : 0.1%、 Nb : 0.1 %這樣地過量含有的話，將會降低加工性、形狀凍 結性。因此，若要含有的話，係將兩者的含量分別限定成 Ti: 0.01 〜0.1%、Nb: 0.01 〜0.1 % 的範圍爲宜。 B ： 0.0003 〜0.0050% B係偏析在沃斯田鐵粒界，而具有抑制從粒界生成肥 粒鐵和抑制肥粒鐵的成長的作用之元素，可以因應必要來 含有。爲了獲得這種效果’其含量係以0.0 0 03 %以上爲宜 ，但是如果含量超過0.0050%的話，就會使加工性降低。 因此，想要含有的話，係將B限定在0.0003〜0.0050 %的 -17- 201207126 範圍爲宜。此外，若想要獲得上述的這種由B所造成的效 果，必須抑制BN的生成，所以係與Ti 一起含有爲宜。 從 1^:0.05~0.5%、0：11:〇.〇5〜0.5%之中所選出的 1 種或2種Both Ti and Nb are elements which can increase the strength of the steel sheet by crystallization strengthening, and can be selectively contained in one or two types as necessary. In order to obtain such an effect, the content of both is preferably Ti: 0.01% or more and Nb: 0.01% or more, but if the contents of both are excessively contained such as Ti: 0.1% and Nb: 0.1%, It will reduce the workability and shape freeze. Therefore, if it is to be contained, the content of both is preferably limited to a range of Ti: 0.01 to 0.1%, and Nb: 0.01 to 0.1%. B: 0.0003 to 0.0050% B-series segregation in the Worthfield iron grain boundary, and has an effect of suppressing the formation of ferrite iron from the grain boundary and suppressing the growth of the ferrite iron, and may be contained as necessary. In order to obtain such an effect, the content is preferably 0.003% or more, but if the content exceeds 0.0050%, the workability is lowered. Therefore, if it is desired to contain B, it is preferable to limit B to 0.0003 to 0.0050% of -17-201207126. Further, in order to obtain the above-described effect by B, it is necessary to suppress the formation of BN, so it is preferable to contain it together with Ti. One or two selected from 1^:0.05~0.5%, 0:11:〇.〇5~0.5%

Ni、Cu都是具有可使鋼板強度増加的作用，並且是 具有可促進内部氧化而提升電鍍層密合性的作用之元素， 可因應必要而選擇性地含有。爲了獲得這種效果，這兩者 的含量分別是Ni : 0.05 %以上' Cu : 0.05%以上爲宜，但 是這兩者的含量若分別是Ni: 0.5%、Cu : 0.5%之過量含 有的話，在退火處理後的冷卻處理中，難以生成所期望量 的波來鐵，於是就無法確保所期望的複合組織，伸長凸緣 性會降低，加工性也會降低。因此，若想要含有的話，係 限定爲Ni: 0.05〜0.5%、Cu: 0.05〜0.5 %的範圍爲宜》 從 Ca ： 0.001 〜0.005 %、REM: 0.001 〜0.005 % 之中選 出的1種或2種Both Ni and Cu have an effect of increasing the strength of the steel sheet, and have an action of promoting internal oxidation to enhance the adhesion of the plating layer, and may be selectively contained as necessary. In order to obtain such an effect, the content of the two is preferably Ni: 0.05% or more and Cu: 0.05% or more, but if the contents of the two are excessively contained in Ni: 0.5% and Cu: 0.5%, In the cooling treatment after the annealing treatment, it is difficult to form a desired amount of the ferrite, and thus the desired composite structure cannot be secured, the elongation flangeability is lowered, and the workability is also lowered. Therefore, if it is desired to be contained, it is limited to Ni: 0.05 to 0.5%, and Cu: 0.05 to 0.5% is preferably one selected from Ca: 0.001 to 0.005%, and REM: 0.001 to 0.005%. 2 kinds

Ca、REM都是有助於控制硫化物的形態的元素，可將 硫化物的形狀予以球狀化，而具有抑制對於硫化物的加工 性尤其是對於伸長凸緣性的不良影響的作用。爲了獲得這 種效果，這兩者的含量分別是Ca: 0.001 %以上、REM: 0.001%以上爲宜，但是這兩者的含量若分別是 Ca: 0.005%、REM: 0.005%這樣地過量含有的話，將會導致介 在物的増加，因而導致發生許多表面缺陷以及内部缺陷。 因此，若想要含有的話，係將其限定成 Ca : 0.001〜 0.005% ' REM ： 0.001 〜0.005 % 的範圍爲宜》 -18" 201207126 除了上述成分以外的其餘部分係由Fe以及不可避免 的雜質所組成的。 本發明的鋼板係具有上述的成分，並且具有由主相也 就是肥粒鐵相以至少含有波來鐵的第二相所成的金屬組織 〇 在本發明的鋼板中，主相也就是肥粒鐵相的面積率， 以相對於整個組織的面積率計，係選定爲75〜90%。肥粒 鐵相的面積率如果未達75%，就無法確保所期望的伸長率 、所期望的擴孔率，會使加工性降低。另一方面，如果肥 粒鐵相的面積率超過了 90%的話，第二相的面積率會降低 ，於是就無法在確保所期望的高強度。因此，乃將主相也 就是肥粒鐵相的面積率限定在75〜90%的範圍。此外，更 好的肥粒鐵相的面積率是8 0〜90%。 又，本發明的鋼板係在第二相中至少含有波來鐵。波 來鐵的面積率，以相對於整體組織的面積率計，係佔1 〇〜 25%。如果波來鐵的面積率未達10%的話，無法確保所期 望的擴孔率，伸長凸緣性會降低，加工性也會降低。另一 方面，如果波來鐵的面積率太多而超過2 5 %的話，肥粒鐵 相與波來鐵的界面會増加，在加工時很容易產生空隙，伸 長凸緣性會降低，加工性也會降低。 又，波來鐵係選定爲平均粒徑5μιη以下的微細粒。如 果波來鐵的平均粒徑係粗大的且超過5μιη的話，則在鋼板 進行加工之際，應力會集中在波來鐵粒（界面），而產生細 微空隙，因此，伸長凸緣性會降低，加工性也會降低。基 -19- 201207126 於這種理由，乃將波來鐵的平均粒徑限定在5μιη以下 好的是4.0μηι以下。 本發明的鋼板的組織中的第二相，至少是含有波 ，波來鐵相對於第二相的總面積的面積率係70%以上 就是第二相係以波來鐵爲主體的相。波來鐵相對於第 的總面積的面積率如果未達70%的話，硬質的麻田散 、變韌鐵相或殘留7相將變得太多，很容易降低加工 因此，乃將波來鐵相對於第二相的總面積的面積率予 定爲7 0 %以上。更好的是7 5〜1 0 0 %。 在第二相中，除了波來鐵以外，亦可含有：變韌 麻田散鐵、殘留沃斯田鐵（殘留r相）等，但是，尤其 韌鐵、麻田散鐵係屬於硬質相，而殘留r相在進行加 則會發生變態而變態成麻田散鐵，分別都會使得加工 低。因此，這些變韌鐵、麻田散鐵以及殘留沃斯田鐵 是極力地減少爲宜，以相對於整體組織的面積率計， 計爲5%以下爲佳。更好的是合計爲3 %以下。 接下來，說明本發明的鋼板之較佳的製造方法。 選定具有上述成分的鋼素材當作出發素材。鋼素 製造方法雖然並沒有特別限定的必要，但是基於生產 觀點而言，係以利用轉爐、電爐等一般常用的熔製方 將上述成分的熔鋼加以熔製，再利用連續鑄造法等之 常用的鑄造方法來製作成鋼胚等的鋼素材爲佳。此外 可以應用造塊-分塊輥軋法、薄鋼胚鑄造法等。 對於具有上述成分的鋼素材，實施熱軋工序以做 。更 來鐵 ，也 二相 鐵相 性。 以限 鐵、 是變 工時 性降 最好 係合 材的 性的 法來 一般 ，也 成熱 -20- 201207126 軋鋼板。熱軋工序係採用：將鋼素材加熱至1100〜1280 °c 範圍的溫度之後，以熱間輥軋結束溫度爲870〜950°C的條 件來進行熱間輥軋以做成熱軋鋼板，在熱間輥軋結束後， 將該熱軋鋼板在捲取溫度爲3 5 0〜720°C的條件下進行捲取 的這種工序爲佳。 鋼素材的加熱溫度若未達1 10CTC的話，有時候其變形 阻力會變得太高，輥軋荷重變得過大，而難以進行熱間輥 軋。另一方面，如果超過1 28 0°C的話，結晶粒會太過於粗 大化，即使實施熱間輥軋也無法確保所期望的微細的鋼板 組織。因此，進行熱間輥軋的加熱溫度係選定在1 1 00〜 128(TC範圍的溫度爲佳。更好的是未達1280°C » 又，熱間輥軋結束溫度若未達870°C的話，在進行輥 軋中，將會生成肥粒鐵（α相）與沃斯田鐵（r相），很容易 在鋼板中生成帶狀組織。這種帶狀組織，即使在退火之後 ，依然會殘留，有時候會對於所製得的鋼板，使得鋼板的 特性產生異方向性或者成爲降低加工性的原因。另一方面 ，熱間輥軋結束溫度若超過95 0°c的話，熱軋鋼板組織將 變得粗大，有時候即使在退火之後，還是無法獲得所期望 的組織。因此，熱間輥軋結束溫度係選定爲8 7 0〜9 5 0 °C爲 佳。 又，熱間輥軋結束後的捲取溫度若未達3 50°C的話， 將會生成變韌鐵化肥粒鐵、變韌鐵、麻田散鐵等，很容易 變成硬質且非整粒的熱軋組織，即使在其後的退火處理中 ，也會繼承熱軋組織，很容易變成非整粒組織，有時候會 -21 - 201207126 無法確保所期望的加工性。另一方面，如果是在超過72 0 °C的這種高溫條件下，則難以在鋼板的長度方向以及寬度 方向上的整個區域都確保一致性的機械特性。因此，捲取 溫度係選定在3 50〜720°C範圍的溫度爲佳。更好的是500 〜68 0〇C。 針對於經過熱軋工序而製得的熱軋鋼板，接下來，爲 了除去生成在鋼板表面的鏽皮，乃遵循一般的方法，在實 施酸洗之後，並不對於熱軋鋼板實施冷間輥軋，而是直接 在連續退火處理線，實施了進行退火處理及其後續的冷卻 處理之連續退火工序。 退火處理係在A。i變態點〜A。；變態點的第一溫度範 圍內保持5〜400秒的處理。 退火處理的第一溫度範圍內的溫度（加熱溫度）如果未 達Ae,變態點，或者在第一溫度範圍內的保持時間（退火時 間）未達5秒的話，熱軋鋼板中的碳化物尙未充分熔解或 者α相—r相的變態尙未發生或不夠充分，因此其後續的 冷卻處理並無法確保所期望的複合組織，所以無法獲得： 具有可符合所期望的伸長率、擴孔率之延性、伸長凸緣性 之鋼板。另一方面，退火處理的加熱溫度太高而超過Ac3 變態點的話，沃斯田鐵粒的粗大化變得很顯著，即使根據 其後續的冷卻處理，所產生的組織還是粗大化，有時候會 使得加工性降低。此外，在第一溫度範圍內的保持時間（ 退火時間）若超過400秒的話，處理時間太長，消耗的能 源太多，導致製造成本的高漲。基於這種理由，乃將退火 -22- 201207126 處理限定爲在Ael變態點〜Ae3變態點的第一溫度範圍內 保持5〜400秒的處理。 此外，各鋼板的Ael變態點係採用下列的（1)式所計算 出來的値，變態點係採用下列（2)式所計算出來的値。 此外，如果有式中的元素所未包含的元素的情況下，係將 該元素視爲零來計算。Both Ca and REM are elements which contribute to the control of the form of the sulfide, and the shape of the sulfide can be spheroidized, and the effect of suppressing the workability of the sulfide, particularly the elongation flangeability, can be suppressed. In order to obtain such an effect, it is preferable that the content of both is Ca: 0.001% or more and REM: 0.001% or more, but if the contents of the two are excessively contained as Ca: 0.005% and REM: 0.005%, respectively. , will lead to the addition of matter, resulting in many surface defects as well as internal defects. Therefore, if it is desired to contain it, it is limited to Ca: 0.001~0.005% ' REM : 0.001 ~ 0.005 % of the range is suitable -18" 201207126 The remainder except the above components are made of Fe and inevitable impurities. Composed of. The steel sheet of the present invention has the above-described composition, and has a metal structure composed of a main phase, that is, a ferrite-grained iron phase and a second phase containing at least a ferritic iron. In the steel sheet of the present invention, the main phase is also a fat granule. The area ratio of the iron phase is selected to be 75 to 90% based on the area ratio of the entire structure. If the area ratio of the ferrite grain iron phase is less than 75%, the desired elongation and the desired hole expansion ratio cannot be ensured, and the workability is lowered. On the other hand, if the area ratio of the ferrogranular iron phase exceeds 90%, the area ratio of the second phase is lowered, so that the desired high strength cannot be ensured. Therefore, the area ratio of the main phase, that is, the ferrite iron phase, is limited to the range of 75 to 90%. In addition, the area ratio of the fine ferrite iron phase is 80 to 90%. Further, the steel sheet of the present invention contains at least Bola iron in the second phase. The area ratio of the ferrite is 1 〇 to 25% based on the area ratio of the overall organization. If the area ratio of the ferritic iron is less than 10%, the desired hole expansion ratio cannot be ensured, the elongation flangeability is lowered, and the workability is also lowered. On the other hand, if the area ratio of the Borne iron is too much and exceeds 25%, the interface between the ferrite grain iron phase and the Borne iron will increase, and voids are easily generated during processing, and the elongation flangeability is lowered, and the workability is lowered. Will also decrease. Further, the Boron iron is selected as fine particles having an average particle diameter of 5 μm or less. If the average particle diameter of the ferritic iron is coarse and exceeds 5 μm, the stress concentrates on the ferrite particles (interfacial) when the steel sheet is processed, and fine voids are generated, so that the elongation flangeability is lowered. Processability will also decrease. Base -19- 201207126 For this reason, the average particle size of the Borne iron is limited to 5 μm or less, preferably 4.0 μm or less. The second phase in the structure of the steel sheet of the present invention contains at least a wave, and the area ratio of the total area of the ferrite to the second phase is 70% or more, that is, the second phase is a phase mainly composed of the ferrite. If the area ratio of the Borne iron relative to the total area of the first is less than 70%, the hard 麻田散, the toughened iron phase or the residual 7 phase will become too much, and it is easy to reduce the processing. Therefore, the Bora iron is relatively The area ratio of the total area of the second phase is predetermined to be 70% or more. More preferably, it is 7 5~1 0 0 %. In the second phase, in addition to the Borne iron, it may also contain: a toughened granulated iron, a residual Worthite iron (residual r phase), etc., but particularly, the tough iron and the granulated iron are hard phases, and remain. When the r phase is added, it will be metamorphosed and metamorphosed into the granulated iron, which will make the processing low. Therefore, it is preferable to reduce these toughening irons, the smectite iron, and the residual Worth iron, and it is preferable that it is 5% or less with respect to the area ratio of the whole structure. More preferably, the total is less than 3%. Next, a preferred method of producing the steel sheet of the present invention will be described. The steel material with the above ingredients is selected as the starting material. The method for producing a tempering material is not particularly limited. However, from the viewpoint of production, a molten steel of the above composition is melted by a general melting method such as a converter or an electric furnace, and a continuous casting method or the like is used. It is preferable to produce a steel material such as a steel embryo by a casting method. Further, an agglomerate-block rolling method, a thin steel blank casting method, or the like can be applied. For the steel material having the above composition, a hot rolling process is performed. More iron, also two-phase iron phase. In the case of iron limit, it is the best way to reduce the workability of the material, and it is also hot. -20- 201207126 Rolled steel plate. The hot rolling process is carried out by heating the steel material to a temperature in the range of 1100 to 1280 ° C and then hot-rolling at a temperature of 870 to 950 ° C at the end of hot rolling to form a hot-rolled steel sheet. After the hot rolling is completed, the hot-rolled steel sheet is preferably wound up at a coiling temperature of 305 to 720 °C. If the heating temperature of the steel material is less than 1 10 CTC, sometimes the deformation resistance becomes too high, the rolling load becomes too large, and it is difficult to perform hot rolling. On the other hand, if it exceeds 280 °C, the crystal grains are too coarse, and even if hot rolling is performed, the desired fine steel sheet structure cannot be secured. Therefore, the heating temperature for hot rolling is selected to be 1 00 to 128 (the temperature in the TC range is preferably better. It is preferably less than 1280 ° C). Further, if the hot rolling end temperature is less than 870 ° C In the case of rolling, ferrite iron (α phase) and Vostian iron (r phase) are formed, and it is easy to form a band structure in the steel sheet. This band structure, even after annealing, remains It will remain, and sometimes it will cause the directionality of the characteristics of the steel sheet to be different or to reduce the workability for the obtained steel sheet. On the other hand, if the hot rolling end temperature exceeds 95 ° C, the hot rolled steel sheet The structure will become coarse, and sometimes the desired structure cannot be obtained even after annealing. Therefore, the end temperature of the hot rolling is preferably selected from 870 to 950 ° C. If the coiling temperature after the end is less than 3 50 °C, it will produce a toughened ferro-fertilizer iron, toughened iron, and granulated iron, which can easily become a hard and non-granular hot-rolled structure, even in its In the subsequent annealing treatment, the hot rolled structure is also inherited, and it is easy to become non- Whole grain structure, sometimes - 21 - 201207126 can not ensure the desired processability. On the other hand, if it is under such high temperature conditions of more than 72 ° C, it is difficult to be in the length direction and width direction of the steel plate. The entire area ensures consistent mechanical properties. Therefore, the coiling temperature is preferably selected at a temperature in the range of 3 50 to 720 ° C. More preferably, it is 500 to 68 ° C. It is obtained by a hot rolling process. The hot-rolled steel sheet, next, in order to remove the scale formed on the surface of the steel sheet, follows the general method. After the pickling is carried out, the hot-rolled steel sheet is not subjected to cold rolling, but directly to the continuous annealing line. A continuous annealing process is performed to perform annealing treatment and subsequent cooling treatment. The annealing treatment is performed at A.i metamorphosis point ~A. The treatment is maintained for 5 to 400 seconds in the first temperature range of the transformation point. If the temperature (heating temperature) in a temperature range does not reach Ae, the metamorphic point, or the holding time (annealing time) in the first temperature range is less than 5 seconds, the carbide in the hot-rolled steel sheet is not charged. The partial melting or the α phase-r phase metamorphosis does not occur or is insufficient, so the subsequent cooling treatment does not ensure the desired composite structure, so it cannot be obtained: has ductility that can meet the desired elongation and hole expansion ratio. On the other hand, if the heating temperature of the annealing treatment is too high and exceeds the metamorphic point of Ac3, the coarsening of the Worthite iron particles becomes remarkable even if it is produced according to its subsequent cooling treatment. The organization is still coarsened, sometimes reducing the workability. In addition, if the holding time (annealing time) in the first temperature range exceeds 400 seconds, the processing time is too long, and the energy consumed is too much, resulting in high manufacturing costs. For this reason, the annealing-22-201207126 process is limited to a process of maintaining 5 to 400 seconds in the first temperature range from the Ael metamorphic point to the Ae3 metamorphic point. In addition, the Ael metamorphic point of each steel sheet is the enthalpy calculated by the following formula (1), and the metamorphic point is the enthalpy calculated by the following formula (2). In addition, if there is an element that is not included in an element in the formula, the element is treated as zero.

Acl 變態點（°C ) = 723+29.1Si-10.7Mn-16.9Ni + 16.9Cr+6.38W+290As • · ·. (1 )式Acl metamorphic point (°C) = 723+29.1Si-10.7Mn-16.9Ni + 16.9Cr+6.38W+290As • · ·. (1)

Ac3 變態點（。(：）=910-203 /€ + 44.73卜30^111+700?+400八1-15.21^-1 lCr-20Cu + 31.5Mo + l〇4V+400Ti+13.1W+120As ·· ·· (2)式 此處的 C，Si，Μη，Ni，Cr，W，As，C，P，A1，Cu ，Mo，V，Ti係各元素的含量（質量％)。 又，退火處理後的冷卻處理，係從上述第一溫度範圍 內起迄700。(：爲止，以平均爲5 °c/秒以上的冷卻速度來進 行冷卻，並且在700 °c〜400 °c的第二溫度範圍內的滯留時 間選定爲3〇〜400秒的處理。 從第一溫度範圍內起迄700 °C爲止的平均冷卻速度若 未達5 °C /秒的話，肥粒鐵生成量増加太多，無法獲得所期 望的複合組織，加工性會降低’有時候會無法確保所期望 的拉伸強度（540 MPa以上）。因此’乃將從第一溫度範圍 內起迄700。(：爲止的冷卻速度限定爲平均是5 °C/秒以上。 更好的是2〇°C /秒以下；最好是5〜15°C /秒。 -23- 201207126 又，在700°C〜400°C的第二溫度範圍內的滯留時間 對於含在第二相內的波來鐵的形成而言係重要的因素。 處所稱的「滯留時間」係指：在上述第二溫度範圍內滯 的時間，係包含：在該第二溫度範圍內的特定溫度條件 進行保持的情況、在該第二溫度範圍內以特定的冷卻速 進行冷卻的情況、以混合這兩種情況的方式來進行冷卻 情況。在第二溫度範圍內的滯留時間若未達3 0秒的話 會因爲波來鐵變態尙未生成，或者波來鐵的生成量不夠 分，而無法確保所期望的複合組織。另一方面，如果在 二溫度範圍內的滯留時間太長而超過400秒的話，生産 會降低。因此，乃將第二溫度範圍內的滯留時間限定在 〜400秒的範圍。更好的是150秒以下。此外，在第二 度範圍內之在7〇〇〜550 °C的溫度域的冷卻時間係選定 1 0秒以上，亦即，在7 0 0〜5 5 0 eC的溫度域的冷卻速度 採用平均爲1 5 °C /秒以下的做法，能夠確保所期望的波 鐵量，所以是較好的做法。在700〜550°C的溫度域的冷 時間若未達1〇秒的話，波來鐵的生成量不夠充分，無 獲得所期望的複合組織，有時候無法確保所期望的加工 〇 以下將依據實施例來更進一步具體地說明本發明。 ，本發明並不侷限於這些實施例所揭示者》 [實施例] 先熔製出如表1所示的成分的熔鋼，再利用一般常 此 留 下 度 的 充 第 性 30 溫 爲 係 來 卻 法 性 又 用 -24- 201207126 的方法製作成鋼素材。針對於這些鋼素材，以表2所示的 加熱溫度、熱間輥軋結束溫度的條件來進行熱間輥軋，以 製作成厚度爲1.6mm的熱軋鋼板，熱間輥軋結束之後，以 表2所示的捲取溫度來將其捲取成鋼帶捲狀。然後實施酸 洗。此外，針對於一部分的熱軋鋼板（厚度爲3.2 mm)，在 酸洗之後，又實施輥軋率爲50%的冷間輥軋，以做成厚度 爲1.6mm的冷軋鋼板來當做比較例。 針對於所製得的熱軋鋼板或冷軋鋼板，又以表2所示 的條件，實施連續退火工序而製作成退火鋼板，該連續退 火工序則是包含：加熱至第一溫度範圍內的溫度並且保持 該溫度之退火處理；以及從第一溫度範圍內的溫度起迄 700 °C爲止係以表2所示的平均冷卻速度來進行冷卻，而 且在第二溫度範圍內之中的700〜5 50°C係以表2所示的冷 卻速度（冷卻時間）來進行冷卻，並且在700〜400°C的第二 溫度範圍內的滞留時間係選定表2所示的滯留時間之冷卻 處理。此外，表2所示的各鋼板的變態點係採用上述的（1) 式、（2)式所計算出來的値。 從所製得的退火鋼板採取出試驗片，並且實施了：組 織觀察、拉伸試驗、擴孔試驗。試驗方法係如下所述。 (1)組織觀察 從所製得的退火鋼板採取出組織觀察用試驗片，將與 輥軋方向呈平行的剖面（L剖面）加以硏磨，以硝酸乙醇溶 液予以腐蝕，使用掃描型電子顯微鏡（倍率：3000倍）來針 -25- 201207126 對金屬組織觀察三個視野以上，並且進行攝影，測定出組 織的種類、各相組織之相對於整體組織的面積率，再計算 出第二相的總面積之相對於整體組織的面積率。而且也計 算出含在第二相內的波來鐵的平均結晶粒徑。此外，波來 鐵的平均結晶粒徑係先測定出各波來鐵粒的面積，從該面 積計算出相當於圓的直徑，再將所獲得的各粒子的相當於 圓的直徑予以算術平均，而作爲波來鐵粒的平均結晶粒徑 。所測定的波來鐵的粒數係20個以上。此外，也計算出 波來鐵的第二相之相對於總面積之面積率。 (2) 拉伸試驗 從所製得的退火鋼板採取出JIS 5號試驗片（亦即，拉 伸方向係和與輥軋方向構成垂直相交的方向一致者），再 依據〗IS Z 224 1的規定來實施拉伸試驗，以求出拉伸特性 (降伏點（YP)、拉伸強度（TS)、伸長率（E1))。 (3) 擴孔試驗 從所製得的退火鋼板採取1〇〇 mm見方的擴孔試驗片 。然後，依據日本鋼鐵聯盟所制定的規格JFST 1001 -1996 的規定，來實施擴孔試驗，以求出擴孔率λ (%)。 將所獲得的結果顯示於表3。 -26- 201207126 【i】 1 適合例 |適合例1 1適合例J 適合例 比較例 比較例 比較例 比較例| 適合例 適合例 丨適合例 適合例 適合例 [適合例1 丨適合例」 比較例1 比較例 比較例 _ φ 链 CaJREM 1 1 1 1 1 1 1 1 1 1 1 1 1 1 B£M：0.002 1 1 1 NiCu 1 1 1 1 1 1 1 1 1 1 1 1 NiO.2 1 1 1 1 1 n 1 1 1 1 1 1 1 1 1 1 1 1 ΒΌ.0012 1 I 1 1 1 1 1 n,Nb 1 1 1 1 1 1 1 1 1 1 1 Nb.U0311 Ti：0.022 1 1 1 1 1 1 Ογ,ΥΜο 1 | Cr：0.35 | 1 1 1 1 1 1 Mo：0.1 1 v〇-i 1 1 1 1 1 1 1 1 z 1 0.0038 1 | 0.002Θ | 1 0.0029 1 1 0.0025 1 1 0.0034 1 1 0.00411 | 0.0034 | I 0.Q036 | | 0.0029 | | 0.0039 | Γαοο^Ι 1 0.0028 1 | 0.0039 | 1 0.0034 ] 1 0.00411 .0.0035 0.0035 I 0.0038 1 0.043 1 | 0.035 | 1 0·036 1 1 0.035 1 1 0.043 I 1 0.042 1 | 0.039 | [0.041 | | 0.03B | | 0.037 | 1 0.037 1 1 0.040 1 | 0.037 | 1 0.042 1 0.042 |α〇38| |a〇43| 1 0.036 1 CO 1 0.002! | 0.0021 1 0.002 1 10.0011 10.0011 1 0.0Q2 1 10.0011 10.0011 I 0.0011 10.0011 1 0.002 1 10.0011 10.0011 1 0.002 1 | 0.002 | 1 0.003 1 | 0.002 | 1 0.0011 mv Pk 1 0.014 1 | 0.023 1 1 C.013 1 1 0.015 | 0.013 1 1 0.015 I I 0.012 | | 0Ό12 | 10.0101 | 0.015 I 1 0.015 1 1 0.013 1 | 0.016 | 1 0.015 1 10.0111 1 0.014 1 | 0.013 | 1 0.0121 1 [mi 0.80 1.40 o S 0.75 1.23 0.62 0.88 0^4 0.82 0.91 [mi UL24J 1 1.32 i 田 0.72 0.72 1.3D Ud 1C 〇 L02 L〇^il 0.80 1.00 1.02 lm\ L43 1.00 LmiJ Q.40 ϋ 1〇^〇1 1 0.09 1 |〇.09 1 1 0.14 1 | 0JQ9 | | 0.15 | L〇^4| 0.15」 L〇^ 0.13 L〇^ L044J 0.12| o d d 1 0.13 1 翳 Να < Cfi ϋ P ω| 〇l x\ z 0 N σι oil -27- 201207126Ac3 metamorphic point (.(:)=910-203 /€ + 44.73卜30^111+700?+400八1-15.21^-1 lCr-20Cu + 31.5Mo + l〇4V+400Ti+13.1W+120As · · · · (2) where C, Si, Μη, Ni, Cr, W, As, C, P, A1, Cu, Mo, V, Ti content of each element (% by mass). The cooling treatment after the treatment is from the first temperature range of 700 to 700. (:: cooling is performed at an average cooling rate of 5 ° C / sec or more, and second at 700 ° c to 400 ° C The residence time in the temperature range is selected to be 3 〇 to 400 seconds. If the average cooling rate from the first temperature range up to 700 °C is less than 5 °C / sec, the amount of ferrite iron is too much. The desired composite structure cannot be obtained, and the workability is lowered. 'Sometimes the desired tensile strength (540 MPa or more) cannot be ensured. Therefore, it will be 700 from the first temperature range. The speed is limited to an average of 5 ° C / sec or more. More preferably 2 〇 ° C / sec or less; preferably 5 to 15 ° C / sec. -23- 201207126 Also, at 700 ° C ~ 400 ° C Second temperature The residence time in the range is an important factor for the formation of the ferrite contained in the second phase. The term "residence time" as used in the space means: the time in the second temperature range mentioned above, including: The case where the specific temperature condition in the second temperature range is maintained, the case where the cooling is performed at a specific cooling rate in the second temperature range, or the case where the two cases are mixed is performed. In the second temperature range If the residence time in the case is less than 30 seconds, the Borne iron metamorphosis will not be generated, or the amount of Borne iron produced will not be sufficient, and the desired composite structure cannot be ensured. On the other hand, if it is within the two temperature range If the residence time is too long and exceeds 400 seconds, the production will be lowered. Therefore, the residence time in the second temperature range is limited to a range of ~400 seconds, more preferably 150 seconds or less. In addition, in the second degree range The cooling time in the temperature range of 7 〇〇 to 550 ° C is selected for more than 10 seconds, that is, the cooling rate in the temperature range of 7 0 0 to 5 5 0 eC is 1 5 ° C / sec. Do the following It is a good practice to ensure the desired amount of wave iron. If the cold time in the temperature range of 700 to 550 ° C is less than 1 〇 second, the amount of Borne iron is not enough, and no expectation is obtained. The composite structure sometimes fails to ensure the desired processing. The present invention will be further specifically described below based on the examples. The present invention is not limited to those disclosed in the embodiments. [Examples] The molten steel of the composition shown in Table 1 is made into a steel material by the method of -24-201207126. With respect to these steel materials, hot rolling was performed under the conditions of the heating temperature and the hot rolling end temperature shown in Table 2 to prepare a hot rolled steel sheet having a thickness of 1.6 mm, and after the hot rolling was completed, The coiling temperature shown in Table 2 was taken up into a steel strip roll. Then pickling is carried out. In addition, for a part of the hot-rolled steel sheet (thickness: 3.2 mm), after pickling, cold rolling was performed at a rolling ratio of 50% to form a cold-rolled steel sheet having a thickness of 1.6 mm as a comparative example. . The hot-rolled steel sheet or the cold-rolled steel sheet produced is subjected to a continuous annealing step to form an annealed steel sheet under the conditions shown in Table 2, and the continuous annealing step includes heating to a temperature within the first temperature range. And maintaining the temperature annealing treatment; and cooling from the temperature in the first temperature range up to 700 ° C at the average cooling rate shown in Table 2, and 700 to 5 in the second temperature range 50 ° C was cooled by the cooling rate (cooling time) shown in Table 2, and the residence time in the second temperature range of 700 to 400 ° C was selected from the cooling treatment of the residence time shown in Table 2. Further, the metamorphic points of the respective steel sheets shown in Table 2 are the enthalpy calculated by the above formulas (1) and (2). A test piece was taken from the obtained annealed steel sheet, and a tissue observation, a tensile test, and a hole expansion test were carried out. The test method is as follows. (1) Observation of the structure A test piece for observation of the structure was taken from the obtained annealed steel sheet, and a cross section (L section) parallel to the rolling direction was honed and etched with a solution of nitric acid in ethanol, using a scanning electron microscope ( Magnification: 3000 times) 针-25-201207126 Observe three fields or more of the metal structure, and perform photography to determine the type of tissue, the area ratio of each phase structure relative to the whole tissue, and then calculate the total of the second phase. The area ratio of the area relative to the overall tissue. Further, the average crystal grain size of the ferrite contained in the second phase was also calculated. Further, the average crystal grain size of the ferrite is obtained by first measuring the area of each of the iron particles, calculating the diameter corresponding to the circle from the area, and arithmetically averaging the diameters of the corresponding circles of the obtained particles. And as the average crystal grain size of the Borne iron particles. The number of particles of the ferrite measured was 20 or more. In addition, the area ratio of the second phase of the Borne iron relative to the total area is also calculated. (2) Tensile test JIS No. 5 test piece was taken from the obtained annealed steel sheet (that is, the direction of the stretching direction coincided with the direction perpendicularly intersecting the rolling direction), and then according to IS Z 224 1 The tensile test was carried out in a predetermined manner to obtain tensile properties (falling point (YP), tensile strength (TS), and elongation (E1)). (3) Reaming test A 1 mm square hole-expanding test piece was taken from the obtained annealed steel sheet. Then, the hole expansion test was carried out in accordance with the specification of the specification JFST 1001 -1996 established by the Japan Iron and Steel Federation to obtain the hole expansion ratio λ (%). The results obtained are shown in Table 3. -26- 201207126 [i] 1 Suitable example|suitable example 1 1 suitable example J suitable example comparative example comparative example comparative example comparative example | suitable example suitable example 丨 suitable example suitable example suitable example [suitable example 1 丨 suitable example] Comparative example 1 Comparative Example Comparative Example _ φ Chain CaJREM 1 1 1 1 1 1 1 1 1 1 1 1 1 1 B£M: 0.002 1 1 1 NiCu 1 1 1 1 1 1 1 1 1 1 1 1 NiO.2 1 1 1 1 1 n 1 1 1 1 1 1 1 1 1 1 1 1 ΒΌ.0012 1 I 1 1 1 1 1 n,Nb 1 1 1 1 1 1 1 1 1 1 1 Nb.U0311 Ti:0.022 1 1 1 1 1 1 Ογ,ΥΜο 1 | Cr:0.35 | 1 1 1 1 1 1 Mo:0.1 1 v〇-i 1 1 1 1 1 1 1 1 z 1 0.0038 1 | 0.002Θ | 1 0.0029 1 1 0.0025 1 1 0.0034 1 1 0.00411 | 0.0034 | I 0.Q036 | | 0.0029 | | 0.0039 | Γαοο^Ι 1 0.0028 1 | 0.0039 | 1 0.0034 ] 1 0.00411 .0.0035 0.0035 I 0.0038 1 0.043 1 | 0.035 | 1 0·036 1 1 0.035 1 1 0.043 I 1 0.042 1 | 0.039 | [0.041 | | 0.03B | | 0.037 | 1 0.037 1 1 0.040 1 | 0.037 | 1 0.042 1 0.042 |α〇38| |a〇43| 1 0.036 1 CO 1 0.002! | 0.0021 1 0.002 1 10.0011 10.0011 1 0.0Q2 1 10.0011 10.0011 I 0.0011 10.0011 1 0.002 1 10.0011 10. 0011 1 0.002 1 | 0.002 | 1 0.003 1 | 0.002 | 1 0.0011 mv Pk 1 0.014 1 | 0.023 1 1 C.013 1 1 0.015 | 0.013 1 1 0.015 II 0.012 | | 0Ό12 | 10.0101 | 0.015 I 1 0.015 1 1 0.013 1 | 0.016 | 1 0.015 1 10.0111 1 0.014 1 | 0.013 | 1 0.0121 1 [mi 0.80 1.40 o S 0.75 1.23 0.62 0.88 0^4 0.82 0.91 [mi UL24J 1 1.32 i Field 0.72 0.72 1.3D Ud 1C 〇L02 L〇^ Il 0.80 1.00 1.02 lm\ L43 1.00 LmiJ Q.40 ϋ 1〇^〇1 1 0.09 1 |〇.09 1 1 0.14 1 | 0JQ9 | | 0.15 | L〇^4| 0.15" L〇^ 0.13 L〇^ L044J 0.12| odd 1 0.13 1 翳Να < Cfi ϋ P ω| 〇lx\ z 0 N σι oil -27- 201207126

【SI 備考 適合例 丨適合例I 適合例 丨比較例 1適合例I 比較例I 適合例I 比較例I 比較例 比較例 比較例I 比較例 比較例1 ，適合例 比較例 適合例 適合例 比較例1 比較例 適合例 變態點 2 868 I 873 I I 673 I |873 I ! 907 | [907 1 1拥5 1 jes 1 |9〇8 I I 827 I 827 65S 831 JH 871 890 1 682 882 I 1905 1 *1 ^J» im | 737 I [737 I [737 I ^52 . Oi 1739 1 I 739 i \Δ 玲 —711」 i〇 P —735 1722 1 00 ¢2 I 738 I |740 I « 743 |755 麵退火工序 冷卻處理 g二溫度範圍 ， 滯留時間 ***(秒） S PH 300 s fH s o 泻 Ο &〇 苒 o s ο s 31 s 另 SI S 冷卻速度 ** Ctv 秒）1 s Ο s 〇 Ο s s o ο Ο s e〇 CO s s IQ Β\ ΙΟ s 抓 冷卻時間 …(秒） JO to Ld ΙΟ i〇 o iq i〇 ιο 芑 § IO !〇 宕 ΙΛ| 另 ΙΟ Μ 平均冷卻速度 * CCV 秒） ο 扫 to 1C ο s o s C0| s s o ο s ο iS S Ο ο s 退火處理 第一溫度範圍 保持時間 m § 8 — § § ο s o s rH § Ο s g — s s — ο 8 ο B 爸 § ο S s 1 cc) βοο 1 820 |650 | § oo i 1 异 CO § 1850 J 1 8 GO |800 1 800 1 民 00 [820 ] i § 〇0 οο SI i § 1 2 CP CD CD CQ CD <D s 2 CO CO CO s (D CO CO <D 2 ΚΩ j2 冷軋 有無 摧 m m 蚺1 摧 m 堞 擗1 摧 摧 璀 m 捱 摧 摧 课 m 塘 熱軋工序 捲取 酿 e 1 600 1 [600 | | 600 | s 1 660 1 丨 560 | | 560 | 「660 j s \D 1 | 600 | 600 1 \ 640 1 1 640 I I 1 560 1 1 660 1 \ 560 1 600 熱祕 丨束溫度 g [900 1 I 900 1 |900 o 920 |920 | I soo | I soo | 920 J 1 i 900 1 900 1 SOO 900 ^00 Ί ^00 1 900 1 900 | 920 1 SI ε 1200 I 1200 J I 120D | 1200 1 1200 1 | 1200 ] | 1200 ! | 1200 | 1200 I 1200 | | 1200 1 120D 1 1200 1 I 1200 | 義 I 1250 | 1 1250 1 1 1250 1 1 1250 1 1250 m i < ffl CQ PQ ο 〇 o Q »1 N 。丨 x\ ·-» 1廳 σ ζ rH ca CO in ω 00 0) s ㈡ s !9 CD 55 α〇 C> 兜s^^aooi 顏S^SHS篇丨載s<* 00^- ^*** -28- 201207126 00$ 1備考 「適合例 <n 膘 比較例 適合例 適合例 適合例 適合例 比較例 比較例 比較例 比較例 變態點 η α < g 905 I s [905 1 1877 La—77— I 873 1 901 8 00 I 890 1 863 〇0 c〇 c〇 «Μ u < g 765 ΙΟ s | 740 | 1 00 CO 卜 Γ766_ Q> CO 卜 [739 Oi CO t- f-4 w 連續退火工序 冷卻處理 1 第二溫度範圍 丨 滯留時間 ***(秒） 150 j 300 s |300 | g g \C> CO si 〇 宕 冷卻速度 ** CC/秒）丨 s o s oo 〇 s s o wl s o 冷卻時間 **(秒） VO a to a to U3I l〇 至70CTC爲止的1 m 16 &· * s o o Ϊ5 LA u) k〇 s 2 o o 退火處理 第一溫度範圍 •保持時間 (秒） s fH g § s 〇 o o o 100 100 100 o s 100 溫度 CC) | 820 1 | 820 ] 1 穿 09 |840 | | 820 | 820 1600 | | 600 820 620 丨板厚I (nun) s CD CO 2 — co 1-4 iD (0 fH Φ (D «Η 冷軋 有無 m 课 m 鹿 m 摧 m 摧 摧 進 摧 熱軋工序 捲取 溫度 e i i 1 σ s | 600 | ς〇 600 600 | GG0 | o s 1 熱軋結！ 束溫度 g 920 | 920 | |920 ] 1 920 1 o g 900 | 920 | 1 920 1 | 920 | | 900 | 900 加熱 酿 g | 1250 1 | 1250 | |l25〇J 1 12D0 ! 1200 ! 1 1200 1 L1200J 1 1200 1 | 1200 | | 1200 1 | 1200 | m i J % z o N B-l σι κ| 1鋼板 co XJ* c5 CO 09 a> cq 5 sispaoTOO^ ^*** (娶 Ρ)«®®^ί?ι0-,酲盤菝资 s 酲^)poss~ooi (** (irdz)«®dg^STm.ooc»^aislIslfe!_l«s(* -29- 201207126[SI Preparation for Suitable Cases I Suitable Example I Suitable Example 丨 Comparative Example 1 Suitable Example I Comparative Example I Suitable Example I Comparative Example I Comparative Example Comparative Example Comparative Example I Comparative Example Comparative Example 1 Suitable Example Comparative Example Suitable Example Comparative Example 1 Comparative example suitable for metamorphosis 2 868 I 873 II 673 I |873 I ! 907 | [907 1 1own 5 1 jes 1 |9〇8 II 827 I 827 65S 831 JH 871 890 1 682 882 I 1905 1 *1 ^J» im | 737 I [737 I [737 I ^52 . Oi 1739 1 I 739 i \Δ 玲—711" i〇P —735 1722 1 00 ¢2 I 738 I |740 I « 743 |755 Surface Annealing Process cooling treatment g two temperature range, residence time *** (seconds) S PH 300 s fH so Ο Ο & 〇苒 os ο s 31 s Another SI S cooling rate ** Ctv seconds) 1 s Ο s 〇Ο sso ο Ο se〇CO ss IQ Β\ ΙΟ s Scratch cooling time... (seconds) JO to Ld ΙΟ i〇o iq i〇ιο 芑§ IO !〇宕ΙΛ| ΙΟ Μ average cooling rate * CCV seconds) ο sweep to 1C ο sos C0| sso ο s ο iS S Ο ο s Annealing first temperature range hold time m § 8 — § § ο sos rH § Ο sg — Ss — ο 8 ο B Dad § s S s 1 cc) βοο 1 820 |650 | § oo i 1 Different CO § 1850 J 1 8 GO |800 1 800 1 00 [820 ] i § 〇0 οο SI i § 1 2 CP CD CD CQ CD <D s 2 CO CO CO s (D CO CO <D 2 ΚΩ j2 Cold rolling with or without destruction mm 蚺1 Destroy m 堞擗1 Destroy 璀m 挨 Destroy class m Hot rolling Process coiling e 1 600 1 [600 | | 600 | s 1 660 1 丨560 | | 560 | "660 js \D 1 | 600 | 600 1 \ 640 1 1 640 II 1 560 1 1 660 1 \ 560 1 600 heat secret beam temperature g [900 1 I 900 1 |900 o 920 |920 | I soo | I soo | 920 J 1 i 900 1 900 1 SOO 900 ^00 Ί ^00 1 900 1 900 | 920 1 SI ε 1200 I 1200 JI 120D | 1200 1 1200 1 | 1200 ] | 1200 ! | 1200 | 1200 I 1200 | | 1200 1 120D 1 1200 1 I 1200 | Yi I 1250 | 1 1250 1 1 1250 1 1 1250 1 1250 mi < Ffl CQ PQ ο 〇o Q »1 N .丨x\ ·-» 1 hall σ ζ rH ca CO in ω 00 0) s (b) s !9 CD 55 α〇C> pocket s^^aooi face S^SHS article s<* 00^- ^** * -28- 201207126 00$ 1Remarks "Applicable Examples <n 膘Comparative Examples Suitable Examples Suitable Examples Suitable Examples Comparative Examples Comparative Examples Comparative Examples Comparative Examples η α < g 905 I s [905 1 1877 La— 77—I 873 1 901 8 00 I 890 1 863 〇0 c〇c〇«Μ u < g 765 ΙΟ s | 740 | 1 00 CO Γ 766_ Q> CO 卜 [739 Oi CO t- f-4 w continuous Annealing process Cooling treatment 1 Second temperature range 丨 Retention time *** (seconds) 150 j 300 s |300 | gg \C> CO si 〇宕Cooling speed** CC/sec)丨sos oo 〇sso wl so Cooling time ** (seconds) VO a to a to U3I l〇 to 70CTC 1 m 16 &· * soo Ϊ5 LA u) k〇s 2 oo Annealing first temperature range • Hold time (seconds) s fH g § s 〇ooo 100 100 100 os 100 temperature CC) | 820 1 | 820 ] 1 wear 09 |840 | | 820 | 820 1600 | | 600 820 620 丨 plate thickness I (nun) s CD CO 2 — co 1-4 iD (0 fH Φ (D «Η Cold rolling with or without m class m deer m destroying m destroying hot rolling process coiling temperature eii 1 σ s | 600 | ς〇600 600 | GG0 | os 1 hot rolling knot! beam temperature g 920 | 920 | |920 ] 1 920 1 og 900 | 920 | 1 920 1 | 920 | | 900 | 900 Heating Stuff | 1250 1 | 1250 | |l25〇J 1 12D0 ! 1200 ! 1 1200 1 L1200J 1 1200 1 | 1200 | | 1200 1 | 1200 | mi J % zo N Bl σι κ| 1 steel plate Co XJ* c5 CO 09 a> cq 5 sispaoTOO^ ^*** (娶Ρ)«®®^ί?ι0-, 酲盘菝资 s 酲^) Poss~ooi (** (irdz)«®dg^STm.ooc»^aislIslfe!_l«s(* -29- 201207126

【eM 備考 本發明例| 本發明例1 1本發明例1 比較例 1本發明例1 I比較例 本發明例 比較例 比較例 比較例 比較例 比較例 比較例 本發明例I 比較例1 本發明例 本發明例 比較例 比較例I 本發明例 伸長凸緣性 c5 (D t-H 2 132 108 s s ΙΟ QO « CO £ s rH oo fH rH O) 105 拉伸特性 伸長率 E1 (%) 33.4 ! 32.1 ! 31.6 j | 3L8 | 1 34,5 1 128·2 1 Lau- J 132.4 | | 33.6 | 34^ | 33.7 I 130.2 1 28.9 | 33.1 | 138 32.4 31.8 24.7 31,1 32.5 拉伸強度 TS (MPa) | 545 | 552 558 599 553 724 624 L^b____1 624 |518_ 1 I 526 I 63β |672 | 564 ! 1Q82 1 592 Leu____1 Li®__I 535 1 G03 降伏強度 YS (MFa) 436 奪 Ο 均 |463 1 η 1452_I i 1387 | |425_1 429 _1 463 449 «2 ΙΑ (D 462 472 |502 | 402 | CQ ΙΟ 呀 組織 P平均 粒徑 ;(μιπ) Q CO CQ CO CO ei CS CO 1 ¢0 ea c〇 ⑦· 04 1 1 0) c<i 1 CC 1 1 0Q CO 組織分率湎積率） 第二相 P分率** 宙 0) 〇i CO σ> ΟΙ SI Φ1 ΙΟ οι 〇l a Ol 宙 〇 Ol Ol S3 1讼3 1 [15.9 | 12.1 财I 1 15·2 1 丨打-4 1 17.8 I 13.3 J |u.2 1 1 ιι·β 1 U《i 1 1说4 1 | 16.0 | 45.2 1 16.4 I | 16.6 | li^2| g 114.1 殘留，1 1 1 1 1 1 1 1 1 1 1 I t 1 1 1 1 1 1 C4 1 ο 〇· 内 ο 0) CO i-H 〇· oa 12.1 CD d ο \m\ d 452 ο id 15.2 1 寸· * 〇. 12.1 1 15.3 1 16.8 | | 16.2 | §1 1 13.2 1 ΓϊαβΙ SI |ι〇·6 1 1 10.9 1 a §1 §1 1 16.2 1 15.1 ! §1 §1 111.5 | 丨主相1 ^4 87.7 84.5 1 丨84.1 | |87.9 | |83.6 | |848 1 |82.6 | [82.2 ] I 86.7 | 1 88.8 1 1 8Β.2 ! | 85.9 | I 83.6 | | 85.0 | 1 54.8 1 B3.6 |83·4 1 |648 |90.4 | 65.9 m W F+P+M F+P+M F+P+M F+P+M F4P+M+殘留 r· F+M F+P+M F+P+M F+P+M F+P+M F+P+M F+M F+M F+P+M F+M F+P+M F+P+M i F+M F+C | F+P+M4* 殘留 了 鋼板 No. < η CQ υ ϋ P Q N 〇l ffil J 11S r-t CO 10 CO 卜 00 σ> s s s 2 3 IA CD a 00 镟A3>liu,樹田&«钿燄：(卜激)s s®,艇溢田擊芝，镟 * 镟sfefc? -30- 201207126[eM Preparation Example of the Invention | Inventive Example 1 1 Inventive Example 1 Comparative Example 1 Inventive Example 1 I Comparative Example Inventive Example Comparative Example Comparative Example Comparative Example Comparative Example Comparative Example Comparative Example Inventive Example I Comparative Example 1 The present invention EXAMPLES Comparative Example of the Invention Comparative Example I The elongation flangeability of the present invention c5 (D tH 2 132 108 ss ΙΟ QO « CO £ s rH oo fH rH O) 105 Tensile elongation E1 (%) 33.4 ! 32.1 ! 31.6 j | 3L8 | 1 34,5 1 128·2 1 Lau- J 132.4 | | 33.6 | 34^ | 33.7 I 130.2 1 28.9 | 33.1 | 138 32.4 31.8 24.7 31,1 32.5 Tensile strength TS (MPa) | 545 552 558 599 553 724 624 L^b____1 624 |518_ 1 I 526 I 63β |672 | 564 ! 1Q82 1 592 Leu____1 Li®__I 535 1 G03 Falling strength YS (MFa) 436 Ο 均 | 463 1 η 1452_I i 1387 | |425_1 429 _1 463 449 «2 ΙΑ (D 462 472 |502 | 402 | CQ ΙΟ 组织 Organization P average particle size; (μιπ) Q CO CQ CO CO ei CS CO 1 ¢0 ea c〇7· 04 1 1 0) c<i 1 CC 1 1 0Q CO tissue fraction hoarding rate) second phase P fraction ** 宙0) 〇i CO σ> ΟΙ SI Φ1 ΙΟ οι 〇la Ol 〇Ol Ol S3 1 Litigation 3 1 [15.9 | 12.1 Finance I 1 15·2 1 Beating - 4 1 17.8 I 13.3 J | u.2 1 1 ιι·β 1 U"i 1 1 says 4 1 | 16.0 | 45.2 1 16.4 I | 16.6 | li^2| g 114.1 Residue, 1 1 1 1 1 1 1 1 1 1 1 I t 1 1 1 1 1 1 C4 1 ο 〇· 内ο 0) CO iH 〇· oa 12.1 CD d ο \ m\d 452 ο id 15.2 1 inch · * 〇. 12.1 1 15.3 1 16.8 | | 16.2 | §1 1 13.2 1 ΓϊαβΙ SI |ι〇·6 1 1 10.9 1 a §1 §1 1 16.2 1 15.1 ! §1 §1 111.5 | 丨 Main phase 1 ^4 87.7 84.5 1 丨84.1 | |87.9 | |83.6 | |848 1 |82.6 | [82.2 ] I 86.7 | 1 88.8 1 1 8Β.2 ! | 85.9 | I 83.6 | | 85.0 | 1 54.8 1 B3.6 |83·4 1 |648 |90.4 | 65.9 m W F+P+M F+P+M F+P+M F+P+M F4P+M+residual r· F+M F +P+M F+P+M F+P+M F+P+M F+P+M F+M F+M F+P+M F+M F+P+M F+P+M i F +M F+C | F+P+M4* Residual steel plate No. < η CQ υ ϋ PQN 〇l ffil J 11S rt CO 10 CO 00 σ> sss 2 3 IA CD a 00 镟A3>liu, tree field &«钿焰:(卜激)ss®, boat overflowing field, 镟* 镟sfefc? -30- 201207126

00B 1 本發明例 1本發明例I L比較例1 |本發明例| 本發明例 本發明例 比較例 比較例 比較例 比較例 比較例1 伸長凸緣性 I rH ιΗ Ο — LO a Ι-» s § ο § 拉伸特性 伸長率 E1 (%) 1 32.6 1 [3ΖΛ\ 丨 3L1 j | 3L& | 32.0 ! 32.9 1 31.8 35.1 I 32Λ 26.8 32.9 拉伸強度 TS QVIPa) s ci να l〇 寸 s CD 〇0 to s IQ 〇o S 吞 μ t φ § ΙΟ 降伏強度 YS (MPa) 1 eg 呑 〇0 04 cn u> 1 t- 琢 \Δ 〇0 CO «5 这 0) 穿 f 組織 P平均 粒徑 (μιη) Oi c6 03 CO SI C0 呀· CO o c〇 N c〇 — C3 oi Ν CO 組織分率(面積率） 第二相 丨 Ρ分率** 却 00 s 〇0 σ: § f-t S Oi σ> 51 SI o 丨合計1 12.3 | 13.5 j Γΐ7·〇 1 丨尥·7 1 Oi Clj 1咖1 U4〇1 co 00 Ή oi ,10,3 1 殘留r* 1 1 1 1 1 1 1 1 1 -fe S 2 <N 1 «-4 d 09 d o S οί 1 4e fU GO UMi σ> ¢0 3 12.4 00 c〇 U3 Oi 的· S 主相| |85.3 | |86.5 | | 83.0 | 1 87.3 1 lse.i 1 | 86.8 | | 86.0 | 191-71 L§zjJ 90.9 ί 89.7 1 種類 F+P+M+殘留 τ F+P+M F+P+M F+P+M F+P F+P+M F+P+M+殘留 τ F+P+M F+P+M F+P+M F+P s Z 0 N 〇l U3 tD cq ¢5 s Μ 貓Λ3>_3,癍田兹尨钿燄：^燄)卜鈿閎，綴¾田»:s,綴嵌寧<1,織siey (* -31 - 201207126 本發明例的每一個都是兼具有：拉伸強度（TS)爲540 MPa以上的高強度、伸長率（E1)爲30%以上的高延性、擴 孔率（λ )爲8 0%以上的優異的伸長凸緣性之加工性優異之 高強度鋼板。相對於此，在本發明的範圍外的比較例的鋼 板，不是無法獲得所期望的高強度，就是無法獲得所期望 的伸長率，或者無法獲得所期望的擴孔率（Λ)，因而降低 了其加工性。 -32-00B 1 Inventive Example 1 Inventive Example IL Comparative Example 1 | Inventive Example | Inventive Example Inventive Example Comparative Example Comparative Example Comparative Example Comparative Example Comparative Example 1 Elongated Flange Property I rH ιΗ Ο — LO a Ι-» s § § § Elongation of tensile properties E1 (%) 1 32.6 1 [3ΖΛ\ 丨3L1 j | 3L& | 32.0 ! 32.9 1 31.8 35.1 I 32Λ 26.8 32.9 Tensile strength TS QVIPa) s ci να l〇 inch s CD 〇 0 to s IQ 〇o S swallow μ t φ § ΙΟ Falling strength YS (MPa) 1 eg 呑〇0 04 cn u> 1 t- 琢\Δ 〇0 CO «5 This 0) wear f tissue P average particle size ( Μιη) Oi c6 03 CO SI C0 呀· CO oc〇N c〇— C3 oi Ν CO Organizational fraction (area ratio) Second phase split ratio** but 00 s 〇0 σ: § ft S Oi σ> 51 SI o 丨 Total 1 12.3 | 13.5 j Γΐ7·〇1 丨尥·7 1 Oi Clj 1 Coffee 1 U4〇1 co 00 Ή oi ,10,3 1 Residual r* 1 1 1 1 1 1 1 1 1 -fe S 2 <N 1 «-4 d 09 do S οί 1 4e fU GO UMi σ> ¢0 3 12.4 00 c〇U3 Oi · S main phase | |85.3 | |86.5 | | 83.0 | 1 87.3 1 lse. i 1 | 86.8 | | 86.0 | 191-71 L§zjJ 90.9 ί 89.7 1 Type F+ P+M+ residual τ F+P+M F+P+M F+P+M F+P F+P+M F+P+M+ residual τ F+P+M F+P+M F+P+M F+P s Z 0 N 〇l U3 tD cq ¢5 s Μ cat Λ3>_3, 癍田兹尨钿焰:^焰)卜钿闳, 33⁄4田»:s, embellished with lt;1, weaving Siey (* -31 - 201207126) Each of the examples of the present invention has a high tensile strength with a tensile strength (TS) of 540 MPa or more, a high ductility (E1) of 30% or more, and a porosity ( λ ) is a high-strength steel sheet excellent in workability of 80% or more of excellent stretch flangeability. On the other hand, in the steel sheet of the comparative example outside the scope of the present invention, the desired high strength cannot be obtained, that is, the desired elongation cannot be obtained, or the desired hole expansion ratio (Λ) cannot be obtained, thereby reducing the steel sheet. Its processability. -32-

Claims (1)

201207126 七、申請專利範圍： 1. 一種加工性優異之高強度鋼板，其特徵爲： 具有由：以質量％計’含有c : 0.08〜0.15%、Si : 0.5 〜1 · 5 %、Μ η : 0 · 5 〜1 · 5 %、P : 0.1 % 以下、S : 0.0 1 % 以下 、Α1: 0.01〜0.1%、Ν: 0.005 %以下，其餘部分是Fe以及 不可避免的雜質所組成的成分，以及 由作爲主相的肥粒鐵相、與至少含有波來鐵的第二相 所組成的金屬組織； 以相對於整個金屬組織的面積率計，前述肥粒鐵相佔 75〜90 %，前述波來鐵佔10〜25 %，且該波來鐵的平均粒 徑是5μιη以下，並且前述波來鐵相對於前述第二相的全部 面積的面積率係70%以上。 2. 如申請專利範圍第1項所述之加工性優異之高強度 鋼板，其中，在前述成分中又含有：從Cr、V、Mo之中 所選出的一種或兩種以上，而上述Cr、V、Mo的含量， 以質量 ％ 計，C r : 0.0 5 〜0 · 5 %、V : 0 · 0 0 5 〜0.2 %、Μ 〇 : 0 · 0 0 5 〜0.2 %。 3 .如申請專利範圍第1項或第2項所述之加工性優異 之高強度鋼板，其中，‘在前述成分中又含有：從Ti、Nb 之中所選出的一種或兩種，而上述Ti、Nb的含量，以質 量 ％ 計，Ti : 0 · 0 1 〜0 · 1 %、Nb : 0.0 1 〜0.1 %。 4.如申請專利範圍第1項至第3項中任一項所述之加 工性優異之高強度鋼板，其中，在前述成分中又含有：以 質量 ％ 計，B : 〇 . 〇 〇 〇 3 〜0 · 0 0 5 0 %。 -33- 201207126 5 ·如申請專利範圍第1項至第4項中任一項所述之加 工性優異之高強度鋼板，其中，在前述成分中又含有：從 Ni、Cu之中所選出的一種或兩種，而上述Ni、Cu的含量 ，以質量 ％ 計，N i : 0 · 〇 5 〜0.5 %、C u : 〇 〇 5 〜〇 . 5 %。 6 _如申請專利範圍第1項至第5項中任一項所述之加 工性優異之高強度鋼板，其中，在前述成分中又含有：從 Ca、REM之中所選出的一種或兩種，而上述Ca、reM的 含量，以質量 ％計，Ca : 0.001 〜0.005%、REM : 0.001 〜 0.005%。 7.—種加工性優異之高強度鋼板的製造方法，其特徵 爲. 對於具有由：以質量％計，含有C : 0.08〜0.15%、Si :0.5 〜1 · 5 %、Μ η : 0 · 5 〜1 · 5 %、P : 0.1 % 以下 ' s : 0.0 1 % 以下、Α1: 0.01〜0.1%、Ν: 0.005 %以下，其餘部分是Fe 以及不可避免的雜質所組成的成分的鋼素材， 實施下列的熱軋工序以及連續退火工序， 該熱軋工序，係進行熱軋以製作成熱軋鋼板； 該連續退火工序’係在對於前述熱軋鋼板進行酸洗之 後，將該熱軋鋼板在連續退火處理線上，在Aci變態點〜 AC3變態點的第一溫度範圍內保持5〜400秒的退火處理， 以及在該退火處理之後’執行：自前述第一溫度範圍起迄 700°C爲止，以5°C/秒以上的平均冷卻速度進行冷卻，並 且將在7〇〇°C〜400°C爲止的第二溫度範圍內的滞留時間選 定爲30〜400秒的冷卻處理。 -34- 201207126 8 .如申請專利範圍第7項所述之加工性優 鋼板的製造方法，其中，前述熱軋工序，係將 加熱到1 1〇〇〜1 280°C的範圍的溫度之後，進行 溫度被設爲870〜950°C的熱軋以製作成熱軋鋼 軋結束之後，對於該熱軋鋼板進行捲取，而此 度被設爲350〜72 0 °C。 9.如申請專利範圍第7項或第8項所述之 之闻強度鋼板的製造方法，其中，在前述第二 中’在700〜5 50°C的溫度範圍的冷卻時間係初 秒以上。 1 0 .如申請專利範圍第7項至第9項中任 加工性優異之高強度鋼板的製造方法，其中， 中又含有：從Cr、V、Mo之中所選出的—種 ，而上述Cr、V ' Mo的含量，以質量％計， 0 · 5 %、V : 0 · 〇 〇 5 〜0.2 %、Μ 〇 : 0 · 0 〇 5 〜〇 . 2 %。 11. 如申請專利範圍第7項至第10項中任 加工性優異之高強度鋼板的製造方法，其中， 中又含有：從Ti、Nb之中所選出的—種或兩 T i、N b的含量，以質量％計，T i : 〇 . 〇 1〜〇 . 1 % 〜0.1 % 〇 12. 如申請專利範圍第7項至第n項中任 加工性優異之高強度鋼板的製造方法，其中， 中又含有：以質量％計，B : 0.0003〜〇 〇〇5()%。 1 3 ·如申請專利範圍第7項至第1 2項中任 異之高強度 前述鋼素材 熱軋結束時 板，在該熱 時的捲取溫 加工性優異 溫度範圍之 芝選定爲10 —項所述之 在前述成分 或兩種以上 C r ·· 0.0 5 〜 一項所述之 在前述成分 種，而上述 、Nb : 0.01 一項所述之 在前述成分 一項所述之 -35- 201207126 加工性優異之高強度鋼板的製造方法，其中，在 中又含有：從Ni、Cu之中所選出的—種或兩種 Ni、Cu的含量，以質量％計，Ni: 〇.〇5〜〇5〇/。、 〜0.5%。 14.如申請專利範圍第7項至第13項中任—項 工性優異之高強度鋼板的製造方法，其中，在前 又含有：從Ca、REM之中所選出的一種或兩種， 、REM的含量，以質量％計，Ca: 0.001〜0.005% 0.001 〜0.005% » 前述成分 ，而上述 Cu : 0.05 所述之加 述成分中 而上述Ca 、REM : 36 - 201207126 四 指定代表圖： (一） 本案指定代表圖為：無 (二） 本代表圖之元件符號簡單說明：無 201207126 五 本案若有化學式時，請揭示最能顯示發明特徵的化學 式：無201207126 VII. Patent application scope: 1. A high-strength steel sheet excellent in workability, characterized by: having: % by mass %: c: 0.08~0.15%, Si: 0.5 〜1 · 5 %, η η : 0 · 5 〜1 · 5 %, P : 0.1 % or less, S : 0.0 1 % or less, Α1: 0.01 to 0.1%, Ν: 0.005 % or less, and the rest is a component composed of Fe and unavoidable impurities, and a metal structure composed of a ferrite phase iron phase as a main phase and a second phase containing at least a wave iron; the iron phase of the fertiliser grain accounts for 75 to 90%, relative to the area ratio of the entire metal structure, the wave The iron content is 10 to 25%, and the average particle diameter of the ferrite is 5 μm or less, and the area ratio of the entire area of the ferrite to the second phase is 70% or more. 2. The high-strength steel sheet excellent in workability according to the first aspect of the invention, wherein the component further contains one or more selected from the group consisting of Cr, V, and Mo, and the Cr, The content of V and Mo, in terms of mass%, C r : 0.0 5 〜 0 · 5 %, V : 0 · 0 0 5 〜 0.2 %, Μ 〇: 0 · 0 0 5 〜 0.2%. 3. The high-strength steel sheet excellent in workability as described in the first or second aspect of the patent application, wherein 'the foregoing component further contains one or two selected from Ti and Nb, and the above The content of Ti and Nb is, in mass%, Ti: 0 · 0 1 to 0 · 1 %, and Nb: 0.0 1 to 0.1%. 4. The high-strength steel sheet excellent in workability according to any one of the items 1 to 3, wherein the component further contains, in mass%, B: 〇. 〇〇〇3 ~0 · 0 0 5 0 %. The high-strength steel sheet excellent in workability as described in any one of Claims 1 to 4, wherein the above-mentioned component further contains: selected from Ni and Cu. One or two, and the content of the above Ni and Cu, in terms of mass%, N i : 0 · 〇 5 ～ 0.5 %, C u : 〇〇 5 〇 〇 5 %. The high-strength steel sheet excellent in workability as described in any one of Claims 1 to 5, wherein the above-mentioned component further contains one or two selected from Ca and REM. The content of Ca and reM described above is, in mass%, Ca: 0.001 to 0.005%, and REM: 0.001 to 0.005%. 7. A method for producing a high-strength steel sheet having excellent workability, characterized in that it contains C: 0.08 to 0.15% by mass%, Si: 0.5 to 1 · 5 %, Μ η : 0 5 〜1 · 5 %, P : 0.1 % or less ' s : 0.0 1 % or less, Α 1: 0.01 to 0.1%, Ν: 0.005 % or less, and the rest is a steel material composed of Fe and unavoidable impurities. Performing the following hot rolling step and continuous annealing step of hot rolling to produce a hot rolled steel sheet; the continuous annealing step is after pickling the hot rolled steel sheet, and then hot rolling the steel sheet On the continuous annealing treatment line, the annealing treatment is maintained for 5 to 400 seconds in the first temperature range of the Aci transformation point to the AC3 transformation point, and after the annealing treatment, 'execution: 700 ° C from the first temperature range, The cooling was performed at an average cooling rate of 5 ° C /sec or more, and the residence time in the second temperature range of 7 ° C to 400 ° C was selected as a cooling treatment of 30 to 400 seconds. The method for producing a process-quality steel sheet according to the seventh aspect of the invention, wherein the hot-rolling step is performed after heating to a temperature in the range of 1 1 〇〇 to 1 280 ° C. After the hot rolling was performed at a temperature of 870 to 950 ° C to prepare a hot-rolled steel sheet, the hot-rolled steel sheet was taken up, and the degree was set to 350 to 72 ° C. The method for producing a smear strength steel sheet according to the seventh or eighth aspect of the invention, wherein the cooling time in the temperature range of 700 to 5 50 ° C in the second embodiment is equal to or greater than the first second. 10. The method for producing a high-strength steel sheet excellent in workability according to items 7 to 9 of the patent application, wherein the method further comprises: the selected one selected from the group consisting of Cr, V, and Mo, and the Cr , V ' Mo content, in mass %, 0 · 5 %, V: 0 · 〇〇 5 ~ 0.2%, Μ 〇: 0 · 0 〇 5 ~ 〇. 2 %. 11. The method for producing a high-strength steel sheet excellent in workability according to items 7 to 10 of the patent application, wherein the method further comprises: a species selected from Ti or Nb or two T i, N b The content of the high-strength steel sheet having excellent workability, in the range of items 7 to n of the patent application range, in the mass %, T i : 〇. 〇1 〇. Among them, the middle contains: in terms of mass%, B: 0.0003~〇〇〇5()%. 1 3 · If the high-strength steel material is hot-rolled at the end of the hot-rolling condition in any of the 7th to 12th items of the patent application, the temperature range in which the coiling temperature is excellent in the heat is selected as 10 - item The above-mentioned component or two or more types of C r ·· 0.0 5 〜 are in the above-mentioned component species, and the above-mentioned Nb: 0.01 is described in the above-mentioned component-35-201207126 A method for producing a high-strength steel sheet excellent in workability, wherein the content of Ni or Cu selected from Ni or Cu is contained in a mass percentage, and Ni: 〇.〇5~ 〇5〇/. , ~0.5%. 14. The method for producing a high-strength steel sheet having excellent workability according to any one of the seventh to the third aspects of the patent application, wherein the method further comprises: one or two selected from the group consisting of Ca and REM, The content of REM, in mass%, Ca: 0.001 to 0.005% 0.001 to 0.005% » The above-mentioned components, and the above-mentioned components of Cu: 0.05, and the above-mentioned Ca, REM: 36 - 201207126 four designated representatives: a) The representative representative of the case is: no (2) The symbol of the symbol of the representative figure is simple: no 201207126 If there is a chemical formula in the case, please disclose the chemical formula that best shows the characteristics of the invention: none
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