559577 A7 B7 五、發明説明（ 本案請求澳洲專利申請案第PR0480號，申請日2〇〇〇年 9月29曰之優先申請權。 i請先閲讀背面之江意事項存媾¾本筲) 發明背景及概要 本發明係有關一種製造帶鋼之方法。 特別本發明係有關於連續帶鋼鑄造機製造帶鋼。 「帶鋼」一詞用於說明書須瞭解係表示厚度為5毫米 或以下的製品。 申請人於呈雙輥鑄造機的連續帶鋼鑄造機於鎢造帶 鋼領域進行徹底的研究及開發工作。 1€, 概略言之，於雙輥鑄造機連續鑄造帶鋼涉及將溶鋼導 入一對反向旋轉的水平鑄造輥，該等輥内部藉水冷卻，讓 金屬殼固化於移動中的輥表面上，且連同輥被帶至輥間的 靨力部而製造固化帶鋼由輥間的壓力部向下輸送，「壓力 部」一詞用於表示二輥最接近區域。熔鋼可由杓導入較小 的容器内’由該容器流經位在壓力部上方金屬輸送嘴嘴， 因而導引熔鋼進入輥間的壓力部，如此形成一個熔鋼鎢池 支撐於輥且恰於壓力部上方以及沿著壓力部長度方向伸展 的鑄造面上。此種鑄池通常係被侷限於夾持成與輥端面作 滑動接合的側板或堰間，因而擋住鑄池兩端不會向外流， 但也曾經提出例如電磁屏障等其它裝置。於此種雙輥鑄造 機之帶鋼鑄造例如述於美國專利5，184,668，5,277,243及 5·934,359。 當帶鋼·溫度通過由沃斯田體至鐵氧體轉變溫度（俗稱 Ar:、）時，熱滾軋連續鑄造帶鋼而達成厚度減薄3〇_4〇%，可 本紙張尺度適用中國國家標準（CNS) A4規格（210><297公釐） 4 559577 A7 B7 五、發明説明（2 (請先閲讀背面之注意事項再填硌本頁) 製造一種顯微結構其包括超微多角形鐵氧體晶粒及細小鐵 氧體晶粒混合物，該種顯微結構對帶鋼提供優異的機械性 質而無需使用微量合金如鈦、鈮於鋼。八〇溫度隨鋼組成改 變，且為沃斯田體轉成鐵氧體之轉變起點溫度。 根據本揭示提供一種製造具有降伏強度至少400 MPa 及總伸長率至少30%之帶鋼之方法，該方法包括下列步驟： (a) 連續鑄造熔鋼成為帶鋼； (b) 於一個溫度範圍内熱滾軋鑄造帶鋼，讓帶鋼於滾軋 過程中於應變下通過由沃斯田體至鐵氧體轉變，俾製造具 有降伏強度高於400 MPa及伸長率超過30%之帶鋼。 一個具體實施例中，步驟（a)之鑄造帶鋼厚度小於2毫 米。熱滾軋結果獲得帶鋼厚度減薄15至50%及更佳30至 40%。 舉例說明，鑄造帶鋼之顯微結構具有晶粒大小於5-20 毫米之實質細小鐵氧體晶粒，以及具有晶粒大小於卜4微米 範圍之超微鐵氧體晶粒。例如超微鐵氧體晶粒占帶鋼之 30-40% ° 軋機入口溫度可略高於Ar3溫度，結果於軋輥咬入軋件 時實質發生轉變。 為了更完整說明揭示内容，將參照附圖舉例說明，附 圖中： 圖式之簡單說明 第1圖為根據本發明可操作之帶鋼鑄造及滾軋設備之 ’縱剖面圖； 本紙張尺度適用中國國家標準（CNS) A4規格（210X297公釐） 559577559577 A7 B7 V. Description of the Invention (This application claims Australian Patent Application No. PR0480, with the priority of application date of September 29, 2000. i Please read the deposits on the back of the document 媾 筲 筲) invention Background and summary The present invention relates to a method for manufacturing strip steel. In particular, the present invention relates to the production of strip steel by a continuous strip casting machine. The term "strip" is used in the description to understand that it means products with a thickness of 5 mm or less. The applicant carried out thorough research and development work in the field of tungsten steel strip in a continuous strip casting machine as a twin roll casting machine. 1 €, In a nutshell, continuous casting of strip in a two-roller casting machine involves the introduction of molten steel into a pair of counter-rotating horizontal casting rolls. The inside of these rolls is cooled by water to allow the metal shell to solidify on the surface of the moving roll. In addition, the solidified strip is manufactured together with the pressure part between the rolls brought to the rolls. The solidified strip is conveyed downward by the pressure part between the rolls. The term "pressure part" is used to indicate the closest area of the two rolls. The molten steel can be introduced into a smaller container through the 杓. This container flows through the metal conveying nozzle located above the pressure part, so the molten steel is guided into the pressure part between the rollers, thus forming a molten steel tungsten pool supported on the roller and just Above the pressure part and on the casting surface extending along the length of the pressure part. This type of casting pool is usually limited to the side plates or weirs that are held in sliding engagement with the end faces of the rollers, so that the two ends of the casting pool will not flow out, but other devices such as electromagnetic barriers have been proposed. Strip casting in such a two-roll casting machine is described, for example, in U.S. Patents 5,184,668, 5,277,243 and 5.934,359. When the temperature of the strip steel passes from the Worth field to the ferrite transition temperature (commonly known as Ar :,), the hot-rolling continuous casting of the strip steel achieves a thickness reduction of 30-40%, which can be applied to this paper scale in China National Standard (CNS) A4 Specification (210 > < 297 mm) 4 559577 A7 B7 V. Description of the Invention (2 (Please read the precautions on the back before filling out this page) Manufacture a microstructure including ultra-micro A mixture of angular ferrite grains and fine ferrite grains. This microstructure provides excellent mechanical properties to strip steel without the need to use trace alloys such as titanium and niobium in steel. The temperature varies with the composition of the steel, and is The starting temperature for the transformation of Voss body to ferrite. According to the present disclosure, a method for manufacturing a strip steel having a reduced strength of at least 400 MPa and a total elongation of at least 30% is provided. The method includes the following steps: (a) continuous casting The molten steel becomes a strip; (b) Hot-rolled cast strip in a temperature range, which allows the strip to undergo transformation from Vossian to ferrite under the strain during the rolling process, and has a high yield strength. Bands at 400 MPa and elongation exceeding 30% In a specific embodiment, the thickness of the cast strip in step (a) is less than 2 mm. The thickness of the strip is reduced by 15 to 50% and more preferably 30 to 40% as a result of hot rolling. The microstructure has substantially fine ferrite grains with a grain size of 5-20 mm, and ultrafine ferrite grains with a grain size in the range of 4 microns. For example, ultrafine ferrite grains occupy strip steel 30-40% ° The temperature at the inlet of the rolling mill can be slightly higher than the temperature of Ar3. As a result, when the roll bites into the rolling material, a substantial change occurs. For a more complete description of the disclosure, an example will be described with reference to the drawings, in which: Description Figure 1 is a 'longitudinal section' view of strip casting and rolling equipment that can be operated according to the present invention; this paper size applies the Chinese National Standard (CNS) A4 specification (210X297 mm) 559577
、發明説明 第2圖顯示結合於該設備之雙輥禱造機之主要組件； 第3圖為通過雙輥鑄造機部分之縱剖面圖； 第4圖為通過錄造機端部之剖面圖； 第5圖為於第4圖線5-5之剖面圖；以及 第6圖為於第4圖線6-6之視圖。 實施例之样細説明 舉例說明之鑄造及滾軋設備包含概略標示為n之雙輕 缚造機，其製造缚造帶鋼12於傳輸路徑ι〇跨導台13送至夾 緊輥站14。恰在由夾緊輥站14送出後，帶鋼進入熱滾軋機 1 5 ’其包含滾軋站16，於其中被熱滾軋而於加溫下減薄其 厚度。如此滾軋後的帶鋼送出滾軋機以及送至送出台丨7， 於送出台上利用冷卻集管箱18冷卻。然後帶鋼通過夾緊輥 站20之夾緊輥20A間送至捲取機19。 雙輥鑄造機11包含主機架21，其支持一對具有鑄造面 22A之平行鑄造輥22。於鑄造操作期間，熔融金屬由杓22 通過耐火杓出口護罩24送至澆口盤25，由澆口盤通過金屬 輸送噴嘴26送入鑄造輥22間的壓力部27。如此輸送至壓力 部27之熱金屬形成鑄池30於壓力部上方，此鑄池於報末端 係由一對側封堰或板28侷限，側板係藉一對推進器31而施 用於輥之步進端，推進器包含液壓工作缸單元32連結至側 板失持器28A。鑄池30上表面（概略稱作「半月形」液面 可能升高至高於輸送噴嘴底端，讓輸送噴嘴底端浸沒於此 鑄池内部。 錄造棍2 2經水冷卻’讓鋼殼硬化於移動中的報表面殘 本紙張尺度適用中國國家標準（CNS) A4規格（210X297公釐） (請先閲讀背面之注意事項再填寫本頁) •·ί 訂， .¾. 6 559577 A7 _._B7_ 五、發明説明（4 ) 化，且於輥間的壓力部27共同被攜帶而製造硬化帶鋼12， 硬化帶鋼由輥間的壓力部向下輸送。 (請先閲讀背面之注意事項再填寫本頁) 雙輥鑄造機可為美國專利案5，184,668及5,277,243或 美國寻利案5,488,988舉例說明且描述細節的種類，可參考 該等專利案之適當構造細節但非構成本發明之一部分。 設備經構造及組裝而形成單一極大型包圍體，概略標 示為37，包圍體界限密封空間38，帶鋼12於由鑄造輥間的 壓力部至夾緊輥站14入口壓力部39的整個傳輸路徑皆被侷 限於該密封空間内部。 包圍體37係藉多個分開壁區段形成，該等壁區段嵌合 於各個密封連接鍵而形成連續包圍體壁。此等壁區段包含 一個壁區段41其係形成於雙輥鑄造機而包圍鑄造輥，以及 一個壁區段42其向下伸展至壁區段41下方而當廢料箱於其 操作位置時接合廢料箱33上緣，讓廢料箱變成包圍體的一 部分。廢料箱及包圍體壁區段42可藉封43連結，封43係由 陶瓷纖維索嵌合於廢料箱上緣的溝形成，以及接合嵌合至 壁區段42下端的平坦密封氣密墊44。廢料箱33可架設於載 具45上，載具嵌合有輪46於軌47上方，藉此於鑄造操作後 廢料箱可移動至廢料排放位置。工作缸單元40可操作而當 載具45於操作位置時由載具舉起廢料箱，讓其朝向包圍體 壁區段42推送以及壓迫封43。於鑄造操作後，工作缸單元 40被解放而下降廢料箱至載具45上讓廢料箱可被移動至廢 料排放位置。 包圍體37進一步包含一個壁區段48，其係設置套於導 本紙張尺度適用中國國家標準（CNS) A4規格（210X297公釐） 559577 A7 ___ B7 五、發明説明（5 ) 台13周圍且連結至夾緊輥站丨4之框架49，夾緊輥站包括一 對夾緊親14A，·包圍體藉滑動封6〇對夾緊輥密封。如此， 帶鋼經由通過一對夾緊輥14A間離開包圍體38，帶鋼即刻 被送入熱親軋機1 5。夾緊輥50間的空間以及至輥軋機的入 口須儘可能縮小，通常約為5米或以下俾於送進輥軋機之前 控制形成規模。 大部分包圍體壁區段可襯墊耐火磚，廢料箱33可襯墊 而ί火箱或可鱗造的财火概聲。 套住每造輥> 之包圍體壁區段41係形成有側板5 1，側板 設置有凹部52，凹部係成形為側堰板28係藉工作缸單元32 而朝向輥末端加壓時，凹部可扣合承接側堪板夾持器 28Α。側板夾持器28Α與包圍體側壁區段5 1間的界面係藉滑 動封53密封而維持包圍體的密封。封53可由陶瓷纖維索製 成。 工作缸單元32貫穿包圍體壁區段41向外延伸，而於此 %•位置包圍體係藉密封板54喪合至工作紅單元密封，因此 當工作缸單元被作動而朝向輥末端推壓側板時，接合包圍 體壁區段4 1。推進器3 1也移動对火滑件5 5，耐火滑件藉工 作缸單元32的作動移動而關閉包圍體頂的開槽56，最初側 板係經由該開槽***包圍體内部以及進入失持器2 § a用以 施用至輥。當工作缸單元被作動而朝向輥施用側堰板時， 包圍體頂係藉澆口盤、側板夾持器28A及滑件55封閉。藉 此方式，整個包圍體37於鑄造操作前被密封而建立封閉空 間38，因此，限制當帶鋼由鑄造輥前進至失緊輥站14時氧 衣紙張尺度適用中國國家標準（CNS) A4規格（210X297公釐） 559577 A7 _____ Β7 五、發明説明（6 ) 氣對帶鋼12的供給量。最初帶鋼將由包圍體空間38攝取全 部氧氣而於帶鋼上形成氧化皮。但空間38的密封控制含氧 氣氛進入量低於可由帶鋼攝取的氧量。如此於最初啟動期 之後，包圍體空間38内部的氧含量將維持空乏，因而限制 氧氣可用於帶鋼的氧化。藉此方式控制氧化皮的形成而無 需連續進給還原性氣體或非氧化性氣體進入包圍體空間 3 8。為了防止啟動期間的嚴重形成氧化皮，於鑄造開始前 即刻掃除包圍體空間因而降低包圍體内部之初氧濃度，因 而縮短由於來自結氧化皮的包圍體的氧氣氧化通過其中的 帶鋼交互作用結果所需氧濃度穩定時間。包圍體可方便地 使用氮氣掃除。發現初氧含量降至5%至1 〇%將限制包圍體 出口的帶鋼密封至約10微米至17微米，即使於最初啟動期 亦如此。 於典型鑄造機設備，來自鑄造機的帶鋼溫度約為14〇〇 °C，帶鋼送至軋機溫度為約900-1 100°C。帶鋼寬度為0.9米 至1.8米及厚度為約〇·7毫米至2.0毫米。帶鋼速度約為ι·〇米 /秒。發現使用於此等條件下製造的帶鋼，相當可能控制空 氣滲漏至包圍體空間38内部的程度，因而限制於包圍體空 間38送出時帶鋼上氧化皮生長至小於5微米厚度，相當於該 包圍體空間平均氧濃度為2%。包圍體空間38之容積並無特 殊限制，由於鑄造操作的最初啟動期間全部氧氣快速被帶 鋼所攝取，隨後氧化皮的形成單純係由大氣通過封渗漏至 包圍體空間的速率決定。較佳控制此種滲漏速率，讓於軋 機入口的氧化皮厚度為1微米至5微米。實驗顯示帶鋼表面 本紙張尺度適用中國國家標準（CNS) Α4規格（210X297公釐） 9 --------------^------------------、矸------------------線 (請先閲讀背面之注意事項再填1VT本頁) 五、發明説明（7 ) 而要有些氧化皮來防止於熱滾軋期間的炫接與沾黏。特別 研究工作提示需要至少約…至！微米厚度俾續保獲得滿意 的滚軋。需要約8微米及較佳5微米上限來防止滾軋後帶鋼 表面有「軋入皮」缺陷，以及確保終產物上氧化皮厚度不 大於習知熱滾軋帶鋼上的氧化皮厚度。 例如於熱滾軋機1 5熱滾軋帶鋼控制成可於帶鋼溫度 乾圍達成厚度減薄30-40%，於軋機入口的帶鋼溫度範圍約 取中於Ar*3溫度，結果於軋輥咬入軋件時獲得實質轉變。 於此種熱滚軋溫度及減薄條件下熱滾軋連續禱造帶 鋼，產生一種顯微結構其為超細多角形鐵氧體晶粒與細多 角形鐵氧體晶粒之混合物，該顯微結構可對帶鋼提供優異 機械性質，包括降伏強度至少4〇〇 MPa&總伸長率至少 30%。 貫驗工作為本揭示之基礎。實驗工作涉及熱滾軋石夕/ 猛淨靜低碳鋼而達成厚度減薄30-40%，於應變下始於86〇 °C溫度以及通過鋼的At*3溫度。發現此等熱滾軋條件於鎊造 滾軋帶鋼可產生極為細小的顯微結構。特別於此等熱滚札 條件下於接近▼鋼缚造表面約3 0 %厚度係由4微米之赶 細等軸鐵氧體晶粒組成，帶鋼其餘部分具有％2〇微米之極 細多面體等軸鐵氧體顯微結構。所得顯微結構提供優異機 械性質包括降伏強度為4 0 0 Μ P a及總仲長率大於3 〇 %。前述 類型之顯微結構僅於帶鋼係於所述熱滾軋溫度及減薄條件 下熱滾軋時觀察得。此等觀察提示於觀察得之晶粒精製中 應變誘生沃斯田體轉成鐵氧體扮演某種角色。須瞭解於應 559577 A7 B7 五、發明説明（8 ) 變下轉變係於某種溫度範圍進行，因此於開始溫度高於或 m 低於鋼之Ar3溫度案例可獲得可接受的顯微結構。 可未悖離本發明之精髓及範圍對前文發明做出多項 修改。 本紙張尺度適用中國國家標準（CNS) A4規格（210X297公釐） 11 (請先閲讀背面之注意事項再填寫本頁) Φ !___ 559577 A7 B7 五、發明説明（9 ) 元件標號對照 10…傳輸路徑 30…禱池 11…雙輥鑄造機 31…推進器 12…鑄造帶鋼 32…液壓工作缸單元 13…導台 37···包圍體 14…夾緊輥站 38···密封空間 14A…夾緊輥 39…進入壓力部 15…熱滾軋機 40…工作缸單元 16…滾軋站 4卜··壁區段 17…送出台 42…壁區段 18…水噴搶 43…封 19…捲取機 44…氣密墊 20…夾緊輥站 45…載具 20A…失緊輥 46…輪 21…主機架 47…執 22…鑄造輥 48…壁區段 22A…錄造面 49…機架 23…杓 50…夾緊輥 24…耐火杓出口護罩 51…側板 25…洗口盤 52…凹部 26…金屬輸送噴嘴 53…滑動封 27…壓力部 54…密封板 28…側板 55…财火滑件 28A…側板夾持器 56…開槽 (請先閲讀背面之注意寧項再填寫本頁) 本紙張尺度適用中國國家標準（CNS) A4規格（210X297公釐） 122. Description of the Invention Figure 2 shows the main components of the double-roll prayer machine combined with the equipment; Figure 3 is a longitudinal sectional view of the part through the double-roll casting machine; Figure 4 is a sectional view through the end of the recorder; The figure is a sectional view taken on line 5-5 in FIG. 4; and FIG. 6 is a view taken on line 6-6 in FIG. 4. Detailed description of the examples The illustrated casting and rolling equipment includes a double light binding machine, which is generally labeled n, which manufactures the tied steel 12 and transfers it to the pinch roll station 14 on the transom guide 13 in the transport path. Immediately after being sent out by the clamping roller station 14, the strip enters a hot rolling mill 15 'which includes a rolling station 16 in which it is hot rolled and its thickness is reduced under heating. The strips thus rolled are sent out of the rolling mill and sent to the delivery stand 7 and are cooled on the delivery stand by the cooling header 18. The strip is then sent to the coiler 19 through the nip rollers 20A of the nip roller station 20. The twin roll casting machine 11 includes a main frame 21 which supports a pair of parallel casting rolls 22 having a casting surface 22A. During the casting operation, molten metal is sent from 杓 22 to the gate tray 25 through the refractory 杓 exit shroud 24, and from the gate tray through the metal conveying nozzle 26 to the pressure portion 27 between the casting rolls 22. The hot metal thus conveyed to the pressure part 27 forms a casting pool 30 above the pressure part. This casting pool is limited at the end by a pair of side sealing weirs or plates 28. The side plates are applied to the rollers by a pair of thrusters 31 At the forward end, the thruster includes a hydraulic cylinder unit 32 connected to the side plate loser 28A. The upper surface of the casting pool 30 (referred to as the "half-moon shape") may rise above the bottom end of the conveying nozzle, so that the bottom end of the conveying nozzle is immersed inside the casting pool. The paper size of the scraps on the surface of the newspaper is in accordance with the Chinese National Standard (CNS) A4 specification (210X297 mm) (Please read the precautions on the back before filling this page) • Order, .¾. 6 559577 A7 _. _B7_ 5. The description of the invention (4), and the pressure part 27 between the rolls is carried together to manufacture the hardened strip 12, and the hardened strip is transported downward by the pressure part between the rolls. (Please read the precautions on the back first (Fill in this page) The two-roller casting machine can be exemplified and described in US Patent Nos. 5,184,668 and 5,277,243 or US Patent No. 5,488,988, and can refer to the appropriate construction details of these patents but does not form part of the invention. The equipment is structured and assembled to form a single very large enclosing body, outlined as 37. The enclosing body delimits a sealed space 38. The entire transmission path of the strip 12 from the pressure part between the casting rolls to the inlet pressure part 39 of the clamping roll station 14 all It is limited to the inside of the sealed space. The surrounding body 37 is formed by a plurality of divided wall sections which are fitted to each sealing connection key to form a continuous surrounding body wall. These wall sections include a wall section 41 It is formed on a two-roller casting machine to surround the casting rolls, and a wall section 42 extends downwardly below the wall section 41 to engage the upper edge of the waste box 33 when the waste box is in its operating position, so that the waste box becomes surrounded The waste box and the surrounding wall section 42 can be connected by a seal 43 formed by a groove in which the ceramic fiber cable is fitted to the upper edge of the waste box and a flat seal joined and fitted to the lower end of the wall section 42 Airtight pad 44. The waste box 33 can be erected on a carrier 45, which is fitted with a wheel 46 above the rail 47, so that the waste box can be moved to the waste discharge position after the casting operation. The work cylinder unit 40 can be operated while When the carrier 45 is in the operating position, the scrap box is lifted by the carrier to be pushed toward the surrounding body wall section 42 and the seal 43 is pressed. After the casting operation, the working cylinder unit 40 is released and the waste box is lowered to the carrier 45 Allows the waste bin to be moved to the waste Discharge position. The enclosure 37 further includes a wall section 48, which is set to fit the paper size of the guide to the Chinese National Standard (CNS) A4 specification (210X297 mm) 559577 A7 ___ B7 V. Description of the invention (5) Platform 13 The frame 49 around and connected to the clamping roller station 4 includes a pair of clamping rollers 14A, and the surrounding body is sealed by a sliding seal 60 to the clamping roller. In this way, the steel strip passes through a pair of clamping The rollers 14A leave the surrounding body 38, and the strip is immediately sent to the hot-rolling mill 15. The space between the clamping rollers 50 and the entrance to the rolling mill must be as small as possible, usually about 5 meters or less. The mill is controlled before forming the scale. Most of the surrounding body wall sections can be lined with refractory bricks, and the waste box 33 can be lined with fire boxes or scales. The surrounding body wall section 41 surrounding each roller > is formed with a side plate 51, the side plate is provided with a recessed portion 52, and the recessed portion is formed as a side weir plate 28. When the cylinder unit 32 is pressed toward the end of the roller, the recessed portion Snap-on receiving side kanban clamp 28A. The interface between the side plate holder 28A and the side wall section 51 of the enclosure is sealed by the sliding seal 53 to maintain the seal of the enclosure. The seal 53 may be made of ceramic fiber rope. The working cylinder unit 32 extends outward through the surrounding body wall section 41, and at this position the surrounding system is sealed by the sealing plate 54 to the working red unit seal, so when the working cylinder unit is actuated to push the side plate toward the end of the roller , Joining the surrounding body wall section 41. The propeller 31 also moves to the fire slider 5 5. The refractory slider closes the slot 56 surrounding the top of the body by the action of the cylinder unit 32. Initially, the side plate is inserted into the inside of the body through the slot and enters the dislocation. 2 § a for application to a roller. When the cylinder unit is actuated to apply the side weir plate toward the roller, the surrounding body top is closed by the gate plate, the side plate holder 28A, and the slider 55. In this way, the entire enclosure 37 is sealed before the casting operation to establish a closed space 38. Therefore, when the strip is advanced from the casting roll to the tension roller station 14, the size of the oxygen dress paper is restricted to the Chinese National Standard (CNS) A4 (210X297 mm) 559577 A7 _____ Β7 V. Description of the invention (6) The amount of gas supplied to the strip steel 12. Initially, the strip will absorb all the oxygen from the surrounding body space 38 to form scale on the strip. However, the sealing of the space 38 controls the amount of oxygen-containing atmosphere to enter lower than the amount of oxygen that can be taken up by the strip. As such, after the initial start-up period, the oxygen content inside the enclosed volume 38 will remain empty, thus limiting the oxygen available for the oxidation of the strip. In this way, the formation of scale is controlled without the need to continuously feed reducing or non-oxidizing gases into the enclosure space 38. In order to prevent severe scale formation during start-up, the space of the enclosure is removed immediately before casting, thereby reducing the initial oxygen concentration inside the enclosure, thus shortening the result of the strip interaction due to the oxidation of oxygen from the enclosure with scale formation Required oxygen concentration stabilization time. The enclosure can be easily purged with nitrogen. It was found that reducing the initial oxygen content to 5% to 10% seals the strip that restricts the exit of the enclosure to about 10 to 17 microns, even during the initial start-up period. In typical casting machine equipment, the temperature of the strip from the casting machine is about 1400 ° C, and the temperature of the strip to be sent to the rolling mill is about 900-1 100 ° C. The strip has a width of 0.9 m to 1.8 m and a thickness of about 0.7 mm to 2.0 mm. The strip speed is about ι · m / s. It was found that strips manufactured under these conditions are likely to control the extent of air leakage to the interior of the enclosed volume space 38, thus limiting the scale growth on the strip to less than 5 microns when the enclosed volume space 38 is sent out, which is equivalent to The surrounding body space has an average oxygen concentration of 2%. The volume of the enclosed volume 38 is not particularly limited. Since all oxygen is quickly taken up by the strip during the initial start-up of the casting operation, the subsequent formation of scale is simply determined by the rate at which the atmosphere leaks into the enclosed volume through the seal. This leakage rate is preferably controlled so that the scale thickness at the entrance of the rolling mill is 1 micrometer to 5 micrometers. Experiments show that the paper size of the strip surface is applicable to the Chinese National Standard (CNS) Α4 specification (210X297 mm) 9 -------------- ^ ------------ ------ 、 矸 ------------------ line (please read the notes on the back before filling the 1VT page) V. Description of the invention (7) Some oxide scales prevent glare and sticking during hot rolling. Special research job tips need at least about ... to! Micron thickness guarantees satisfactory rolling. An upper limit of about 8 microns and preferably 5 microns is required to prevent "skinning" defects on the surface of the strip after rolling, and to ensure that the thickness of the scale on the final product is not greater than the thickness of scale on the conventional hot rolled strip. For example, in a hot rolling mill, the 15 hot rolling strip steel is controlled to achieve a thickness reduction of 30-40% at the temperature of the strip steel. The strip temperature range at the entrance of the rolling mill is approximately at the Ar * 3 temperature. A substantial transformation is obtained when biting into the rolling stock. Under the conditions of such hot rolling temperature and thinning, continuous rolling of the steel strip is performed to produce a microstructure which is a mixture of ultrafine polygonal ferrite grains and fine polygonal ferrite grains. The microstructure can provide excellent mechanical properties to the strip, including a drop strength of at least 400 MPa & a total elongation of at least 30%. Inspection work is the basis of this disclosure. The experimental work involved hot-rolled stone eve / violet static low carbon steel to achieve a thickness reduction of 30-40%, under strain starting at a temperature of 86 ° C and passing through the steel's At * 3 temperature. It was found that these hot rolling conditions produced extremely fine microstructures in the rolled steel strip. Especially under these hot rolling conditions, approximately 30% of the thickness of the steel binding surface is composed of 4 micron fine equiaxed ferrite grains, and the rest of the strip has a superfine polyhedron of 20 micron, etc. Axial Ferrite Microstructure. The resulting microstructure provides excellent mechanical properties including a drop strength of 400 MPa and a total medium-length ratio of greater than 30%. The microstructure of the aforementioned type is only observed when the strip is hot-rolled at the hot-rolling temperature and thinning conditions described above. These observations suggest that the strain induced the conversion of Voss fields to ferrites in the observed grain refinement plays a certain role. It should be understood that Yu Ying 559577 A7 B7 V. Description of the invention (8) The down-conversion is carried out in a certain temperature range, so an acceptable microstructure can be obtained in cases where the starting temperature is higher or lower than the Ar3 temperature of the steel. Many modifications can be made to the foregoing invention without departing from the spirit and scope of the invention. This paper size applies Chinese National Standard (CNS) A4 specification (210X297 mm) 11 (Please read the precautions on the back before filling out this page) Φ! ___ 559577 A7 B7 V. Description of the invention (9) Component number comparison 10… Transmission Path 30 ... Prayer pond 11 ... Double-roller casting machine 31 ... Propulsion 12 ... Cast strip 32 ... Hydraulic cylinder unit 13 ... Guide plate 37 ... Enclosed body 14 ... Clamping roller station 38 ... Sealed space 14A ... Clamping roller 39 ... entering pressure section 15 ... hot rolling mill 40 ... cylinder unit 16 ... rolling station 4b ... wall section 17 ... delivery stand 42 ... wall section 18 ... water spray grab 43 ... seal 19 ... roll Take-out machine 44 ... airtight pad 20 ... clamping roller station 45 ... carrier 20A ... tightening roller 46 ... wheel 21 ... main frame 47 ... holding 22 ... casting roller 48 ... wall section 22A ... recording surface 49 ... frame 23 ... 杓 50 ... Clamping roller 24 ... Fire-resistant 杓 Exit shield 51 ... Side plate 25 ... Washing plate 52 ... Recess 26 ... Metal delivery nozzle 53 ... Slip seal 27 ... Pressure portion 54 ... Seal plate 28 ... Side plate 55 ... Fortune fire Slider 28A ... Side plate holder 56 ... Slotted (Please read the note on the back before filling this page) This paper size applies to China National Standard (CNS) A4 (210X297 mm) 12