200951233 . 六、發明說明： 【發明所屬之技術領域】 本發明係關於由具有高機械性質且尤其具有機械強度 及均勻伸長率之極有利組合之沃斯田不鏽鋼製成之熱軋板 的製造。 【先前技術】 在汽車行業中，對於製造結構組件而言，一般慣例為 使用各種等級之具有較為複雜或較不複雜之微觀結構之經 塗佈碳鋼板。零件係由厚度處於lmm至3mm範圍内之板 製造。然而，對於一些零件而言，需要同時具有較高耐蝕 性與高可變形性之組合以用複雜拉制操作來生產零件。此 外’已知沃斯田不鏽鋼由於其優良耐蝕性及其機械性質， 尤其其高延性而被廣泛使用。舉例而言，根據Εν 100884 標準由參照1.4318所表示之沃斯田不鏽鋼為已知的，其中 組成含有（含量係以重量表示）：C <0.030%、Si <1〇〇%、 1^11<2.00%、？彡 0.045〇/〇、8幺0.015%、（>:16.50〇/〇至 18.50%、Ni : 6.00〇/〇至 8.00%、N : 0.10%至 0.20%。由於在 至溫下變形期間形成麻田散逋（martensite )，所以此等鋼具 有高機械性質。處於退火狀態之此等鋼之典型機械性質係 如下：屈服強度Rp〇 2 (相應於0.2%應力之習知屈服強度）： 300-400 MPa;均勻伸長率：a 245%、Rm(最大強度）>700 MPa ;乘積 P=Rp0 2 ( MPa) X均勻伸長率=約 15750 MPa.%。 有可能使用此等處於藉由冷軋而加工硬化之狀態之等級： 200951233 C850、C1000_EN_10088-2標準，此等名稱分別相應於85〇 1000 MPa之最小強度。藉由此操作而使屈服強度增 加（Rp〇.2 > 600 MPa)表現為伸長率同時降低（A=3〇%)。 乘積P因而達到約18000 MPa.%e對於某些應用而言，此等 性質令人滿意《然而，若為（例如）使減輕增強而需要在 使用中具有高強度及高先前成形操作能力，其仍為不夠的。 藉由冷軋來加工硬化之一替代方法為在足夠低之溫度 下藉由熱軋來加工硬化。此方法給予較佳之伸長率強度综 ❺ β平衡’但具有在成形期間導致局部變形而引起蠕蟲狀缺 陷之主要缺點。為避免熱軋後未再結晶之標準1.4318鋼上 之此等緯蟲狀缺陷，需要在熱軋後進行退火操作。 【發明内容】 因此，本發明之目的為提供機械性質優於或相當於上 文斤提及之1.4318型#級之機械性質的沃斯田不鑛鋼熱乳 板，該等沃斯田不鏽鋼熱軋板對於製造而言不昂貴且不易 受蠕蟲狀缺陷外觀影響。 本發明之目的亦為提供由沃斯田不鏽鋼製成之熱軋 板，其具有可與大於65〇 MPa之屈服強纟R心或大於⑽ 之均勻伸長率組合之大於21嶋Mpa %之乘積p。 出於此目的，本發明之標的為由沃斯田不鏽鋼製成之 熱札板’其乘積ρ(·ρ ,iurr»、 , ^ Κρ〇·2 ( MPa) χ均勻伸長率（〇/〇))大於 21000 MPa.%，且 其化學組成包含（含量係以重量表示）： 0.015% <C 〇3〇〇/ Λ … * 30/〇 ' 0.5% <Mn ^2% > Si <2% > 16.5% < 200951233200951233. VI. Description of the Invention: TECHNICAL FIELD OF THE INVENTION The present invention relates to the manufacture of hot rolled sheets made of Wostian stainless steel having a highly advantageous combination of mechanical properties and particularly uniform elongation. [Prior Art] In the automotive industry, it is a common practice for manufacturing structural components to use various grades of coated carbon steel sheets having relatively complex or less complex microstructures. Parts are manufactured from sheets with thicknesses ranging from 1mm to 3mm. However, for some parts, it is desirable to have a combination of higher corrosion resistance and high deformability to produce parts with complex drawing operations. Further, the known Vostian stainless steel is widely used due to its excellent corrosion resistance and its mechanical properties, especially its high ductility. For example, the Vostian stainless steel, which is represented by reference to 1.4318 according to the Εν 100884 standard, is known in which the composition is contained (the content is expressed by weight): C < 0.030%, Si < 1〇〇%, 1^ 11<2.00%,?彡0.045〇/〇, 8幺0.015%, (>:16.50〇/〇 to 18.50%, Ni: 6.00〇/〇 to 8.00%, N: 0.10% to 0.20%. Due to the formation of Ma Tian during deformation to temperature The martensite, so these steels have high mechanical properties. The typical mechanical properties of such steels in the annealed state are as follows: yield strength Rp 〇 2 (corresponding to the known yield strength of 0.2% stress): 300-400 MPa; uniform elongation: a 245%, Rm (maximum strength) > 700 MPa; product P = Rp0 2 (MPa) X uniform elongation = about 15750 MPa.%. It is possible to use this by cold rolling The grade of the work hardening state: 200951233 C850, C1000_EN_10088-2 standard, these names correspond to the minimum strength of 85〇1000 MPa respectively. By this operation, the yield strength is increased (Rp〇.2 > 600 MPa) as The elongation is simultaneously reduced (A = 3〇%). The product P thus reaches about 18000 MPa.%e. For some applications, these properties are satisfactory. However, if, for example, the enhancement is needed, it needs to be used. It has high strength and high prior forming operation capability, which is still insufficient. By cold An alternative to work hardening is to work harden by hot rolling at a temperature low enough. This method gives better elongation strength, helium beta balance, but has localized deformation during forming, causing worm-like defects. The main disadvantage is that in order to avoid such weft-like defects on the standard 1.4318 steel which is not recrystallized after hot rolling, an annealing operation is required after hot rolling. SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide mechanical properties superior to or Corresponding to the mechanical properties of the 1.4318 type # mentioned above, the Vostian stainless steel hot-rolled sheet is not expensive for manufacturing and is not susceptible to the appearance of worm-like defects. It is also an object of the present invention to provide a hot rolled sheet made of Wostian stainless steel having a product which can be combined with a yield strength R greater than 65 MPa or a uniform elongation greater than (10) greater than 21 嶋 Mpa %. p. For this purpose, the object of the invention is a hot plate made of Worthian stainless steel whose product ρ(·ρ, iurr», , ^ Κρ〇·2 (MPa) χ uniform elongation (〇/ 〇)) is greater than 21000 MPa.%, Its chemical composition is included (content is expressed by weight): 0.015% < C 〇 3 〇〇 / Λ ... * 30 / 〇 ' 0.5% < Mn ^ 2% > Si < 2% > 16.5% < 200951233
Cr <18% ' 6% ^Ni ^7〇/〇 . s <0.015% ' P <0.045% ^ A1 < 0.050%、0.15% <Nb <0.31%、0.12% SN <0.16%，Nb 及 N含量係如下：Cr <18% ' 6% ^Ni ^7〇/〇. s <0.015% ' P <0.045% ^ A1 < 0.050%, 0.15% <Nb <0.31%, 0.12% SN <0.16 The %, Nb and N contents are as follows:
Nb/8 + 0.1% 彡Nb/8 + 0.12%，視情況：0.0005% <0·0025%，Mo <0.6%，組成之其餘部分由鐵及由熔煉所產 生之不可避免之雜質組成。 根據一較佳具體實例，鋼之鈮及氮含量（以重量表示） 係如下：0.20% 彡Nb 幺〇·31 %、0.12% SN <0.16%。 本發明之標的亦為由根據上述組成中之任一者之沃斯 田不錄鋼製成之熱軋板，其屈服強度Rp<) 2大於65〇 MPa， 特徵在於該鋼之平均沃斯田晶粒大小小於6微米，未再結 晶表面分率介於30%與7〇%之間且鈮完全呈沈澱物形式。 本發明之標的亦為由根據上述特徵中之任一者之沃斯 田不錄鋼製成之熱軋板，其均勻伸長率大於45%，特徵在 於铌未完全沈澱。 本發明之標的亦為製造屈服強度RpG 2大於650 MPa之 由沃斯田不鏽鋼製成之熱軋板的方法，其中：提供由具有 根據上述組成中之任一者之組成之鋼所製成之半成品；接 著將該半成品再加熱至介於125CTC與132(TC之間的溫度； 且接著在輥軋結束溫度低於990°C且在最後2個精軋機座上 之累積縮減比（cumulative reduction ratio ) e大於30%之情 況下輥軋該半成品。 根據一特定具體實例，提供由具有上述含有0.20% s Nb S 0.31%、0.12% <0.16%之組成的鋼製成之半成品 200951233 且接著在輥軋結束溫度低於97〇〇c w w況下輥軋該半成品。 本發明之標的亦為製造均勻伸長率 τ我年大於45〇/〇 田不鏽鋼製成之熱軋板的方法，其中： 4 述組成中之任-者之組成之鋼所製成之半成=具有根據^ 半成品再加熱至介於1250eC與1320¾之門的。，接著將该 l疋間的溫度；且接著 ❹ 在輥軋結束溫度高&刚代之情況下輕軋該半成品。本發 明之標的亦為製造乘積P(RpG.2(MPa)〜句伸長 大於21000 MPa.%之由沃斯田不鐘 .^ ^ _ 不鏽鋼製成之熱軋板的方 法，其中·提供由具有根據上述組成中 .^ Αι 之任一者之組成的 鋼所製成之半成品；接著將該半成σ /千風110再加熱至介於1250t 與1320°C之間的溫度；且接著熱軋該半成品。 本發明之標的亦為根據上述特徵中之任一者或由上述 方法中之任一者所製造的由不鏽鋼製成之熱軋板之用途， 其係用於製造汽車領域令之結構組件。 【實施方式】 經由下文以實例方式給出之描述過程，本發明之其他 特徵及優勢將變得顯而易見。多次試驗之後，本發明者已 展示上文所提及之各種需求係、藉由奉行下列條件來滿足： 就鋼之化學組成而言，碳含量須等於或小於_0%以 避免易受粒間腐餘影響之風險。出於獲得大於65〇胸之 屈服強度之目的，碳含量須等於或大於〇 〇15%。 猛類似於石夕為已知其在液體狀態下具去氧性質之元素 且已知用於尤其藉由與硫結合來增加熱延性。此外，在環 200951233 境溫度下Μ促進沃斯田相之穩定性且降㈣差能（_叫 fauh energy)。其亦增加氮氣之溶解性。當錳含量介於〇 5% 與2%之間時，可以低成本獲得此等有利作用。 矽類似於錳為通常出於使液體鋼去氧之目的添加之元 素》矽亦藉由固溶體硬化或藉由其對肥粒鐵古含量之作用 來增加屈服強度及拉伸強度。然而，高於2%，則降低可焊 接性及熱延性。鉻為熟知用於增強在水性介質中之抗氧化 性及耐蝕性之元素。當其含量處於〗6 5%與18%之間時，可 令人滿意地獲得此作用。鎳為確保鋼之沃斯田結構在環境 溫度下足夠穩定之必要元素。須相對於組成中促進α相形 成之其他元素（諸如鉻）或促進r相形成之彼等元素（諸 如碳及氮）來決定最佳含量。當其含量等於或大於6%時， 其對結構穩定性之作用為足夠的。高於7%，則由於此添加 元素之費用而使生產成本過度增加。 鉬能夠增強抗孔蝕性。視情況，可以處於至多〇 6%之 範圍内之量來進行钥之添加。硼係用於改良鋼之可鍛造 性。視情況，可以介於0.0005。/。與0_0025%之間的量來進行 蝴之添加。添加更大量會顯著降低燃燒溫度。 硫為尤其降低熱可鍛造性及耐姓性之元素_其含量須保 持等於或小於0.015%。磷同樣降低熱延性_其含量須小於 〇·〇45%以獲得令人滿意之結果。 銘為用於使液體金屬去氧之有效試劑。與上文所提及 之矽及經含量組合，當其含量等於或小於〇 〇5〇%時，獲得 最佳作用。出於製造具有兩機械性質之沃斯田不錄鋼之目 200951233 的’鈮及氮為本發明之重要元素。 對於給定熱軋結束溫度而言，鈮在熱軋期間使再結晶 延遲，添加其使得較高加工硬化因子得以保持（將熱軋稱 作「加工硬化」），因此增強此鋼之拉伸強度。其類似於^ 而一般用於防止碳化鉻形成（EN 1 458〇及EN i 455〇經 穩定之沃斯田不鏽鋼）。最終，其可引起提供抗熱蠕變性之 改良的金屬間相形成。氮為填隙固溶體中之硬化元素就 此方面而言其最尤其增強屈服強度。其亦已知在固溶體中 β 作為沃斯田相之有效穩定劑且作為碳化鉻沈殿之延 遲劑。氮之溶解度在凝固期間經歷最大值-含量過高導致金 屬中之體積缺陷形成。 出於硬化之目的而組合添加銳及氮在沃斯田不鏽鋼中 有些不t見。纟本發明之情形中，月具有與上文所提 及之1.4318鋼之組成相接近之組成的不鏽鋼可有利地獲益 於鈮及氮之特定組合添加，出於獲得某些機械性質之目的 而在確疋條件下使該特定組合添加最佳化，該等確定條件 ® 係如下文所述： 首先’已表明氮含量處於〇.!2%至〇.16%之範圍内，同 時鈮含量處於〇.15%至〇 31%之範圍内，鈮及氮含量係如 下.Nb/8 + 0.1% SNb/8 + 0.12% (關係 1),使得在不 需要如習知1.4318鋼t之輥軋後退火的情況下製造意欲拉 伸之具有高機械性質之熱軋板成為可能該拉制零件不經 受螺蟲狀缺陷之形成。 在熱軋結束期間出現之氮化物NbN沈澱降低固溶體中 200951233 氮之量。在所有可用之鈮完全沈澱後，上述關係（1)使得 固溶艘中之氮保持與1 4318等級中之氮同樣多（N >0.1%)。 此因而使得獲得沃斯田艎於環境溫度下之相同介穩定 性（metastability)成為可能。藉由增加n含量來降低Ni 含量之可能性受限於凝固期間氮於鋼中之溶解度限制。對 於本發明之鋼的Cr、Μη及Ni含量而言，氮含量須等於或 小於0.16%。 須存在足夠量之鈮以獲得硬化作用且使再結晶延遲。 此量須經調適以獲得高於輥軋結束溫度下之NbN溶線以在 熱軋結束時獲得沈澱。 本發明之鈮及氮含量使得在熱軋後能夠獲得實質NbN 沈澱。 組合添加0.15%至0.31%之鈮（較佳0.20%至0.31%之 銳）及0.12%至〇.16%之氮，鈮及氮含量係如下：训/8 + 〇.1〇/〇 <Nb/8 + 0.12%’使得獲得有利屈服強度/伸長率組合成 為可能，其乘積p大於21000 MPa.%。 除鐵之外，組成之剩餘部分由自熔煉所產生之不可避 免之雜質組成，諸如Sn或Pb。 本發明之製造方法係如下來實施： 熔煉具有上文所說明之組成之鋼。此熔煉之後，可繼 而將此鋼鑄造成鑄塊，或在最通常狀況下，以（例如）厚 度處於150 mm至250 mm範圍内之平板形式連續鑄造。亦 可介於鋼對轉式輥之間以厚度為幾十毫米之薄板形式進行 缚造°首先將此等鱗造半成品加熱至介於^⑽乞與132〇。〇 200951233 之間的溫度。臟溫度之目的在於使任何銳基沈殿物（氮 . 化物及碳氮化物）溶解。 然而，溫度須低於132(rc以避免過於接近可在某些隔 離區域中達到之固相線溫度且避免導致局部開始呈現不利 於熱成形之液體狀態。在介於對轉式輥之間直接鑄造薄板 之狀況下，在低於125(TC之溫度下開始之熱軋此等半成品 之步驟可在鑄造後直接進行，以便在此狀況下不需要中間 再加熱步驟。 ❹ 輥軋一般在尤其包含粗軋機座及精軋機座之連績熱軋 鋼機上進行。已表明尤其藉由控制最後2個精軋機座中之 縮減比（reduction ratio)來獲得尤其高之屈服強度Rp〇2 : 若進入倒數第二個精軋機座之板之厚度表示為〜_2且退出 最後一個精軋機座之板之厚度表示為eN，則經過最後2個Nb/8 + 0.1% 彡Nb/8 + 0.12%, depending on the case: 0.0005% < 0·0025%, Mo < 0.6%, the remainder of the composition consists of iron and unavoidable impurities produced by smelting. According to a preferred embodiment, the niobium and nitrogen content (expressed by weight) of the steel are as follows: 0.20% 彡Nb 幺〇·31%, 0.12% SN < 0.16%. The subject matter of the present invention is also a hot rolled sheet made of Wostian unrecorded steel according to any of the above compositions, having a yield strength Rp <) 2 greater than 65 MPa, characterized by an average Worthfield of the steel. The grain size is less than 6 microns, the non-recrystallized surface fraction is between 30% and 7%, and the ruthenium is completely in the form of a precipitate. The subject matter of the present invention is also a hot rolled sheet made of Worthfield unrecorded steel according to any of the above features, having a uniform elongation of more than 45%, characterized by insufficient precipitation of the crucible. The subject matter of the present invention is also a method of producing a hot rolled sheet made of Wostian stainless steel having a yield strength RpG 2 of more than 650 MPa, wherein: it is provided from a steel having a composition according to any of the above compositions. a semi-finished product; the semi-finished product is then reheated to a temperature between 125 CTC and 132 (TC; and then at the end of the rolling temperature below 990 ° C and cumulative reduction ratio on the last two finishing stands (cumulative reduction ratio Rolling the semi-finished product with e greater than 30%. According to a specific embodiment, a semi-finished product 200951233 made of the above-mentioned steel having a composition of 0.20% s Nb S 0.31%, 0.12% < 0.16% is provided and then The semi-finished product is rolled at a rolling end temperature of less than 97 〇〇cww. The object of the present invention is also a method for producing a hot-rolled sheet made of stainless steel having a uniform elongation τ of more than 45 〇/〇田, wherein: 4 The semi-finished steel made up of the composition of the composition is reheated to the door between 1250eC and 13203⁄4 according to the semi-finished product, and then the temperature between the turns; and then the end of the rolling High temperature & just In this case, the semi-finished product is lightly rolled. The object of the present invention is also a hot-rolled sheet made of stainless steel, which is manufactured by Wolsterfield, which has a product P (RpG.2 (MPa)~ sentence elongation of more than 21000 MPa.%). And a method of providing a semi-finished product made of steel having a composition according to any one of the above compositions; and then reheating the semi-integrated σ / thousand wind 110 to between 1250 t and 1320 ° C And the subsequent hot rolling of the semifinished product. The subject matter of the present invention is also the use of a hot rolled sheet made of stainless steel according to any one of the above features or manufactured by any of the above methods. Other features and advantages of the present invention will become apparent from the following description of the <RTIgt; The various requirements mentioned are met by the following conditions: For the chemical composition of steel, the carbon content must be equal to or less than _0% to avoid the risk of being susceptible to intergranular decay. The purpose of the yield strength of the chest The carbon content must be equal to or greater than 〇〇15%. It is similar to Shi Xi, an element known to have deoxidizing properties in a liquid state and is known to increase hot ductility, especially by combining with sulfur. Ring 200951233 At ambient temperature, it promotes the stability of the Worth field and reduces (4) the difference energy (_called fauh energy). It also increases the solubility of nitrogen. When the manganese content is between 〇5% and 2%, This advantage is obtained at a low cost. 矽 Similar to manganese, an element that is usually added for the purpose of deoxidizing liquid steel. 矽 Also hardened by solid solution or by its effect on the ancient content of ferrite iron Strength and tensile strength. However, above 2%, the weldability and hot ductility are lowered. Chromium is an element well known for enhancing the oxidation resistance and corrosion resistance in an aqueous medium. This effect is satisfactorily obtained when the content is between about 5% and 18%. Nickel is an essential element to ensure that the steel's Vostian structure is sufficiently stable at ambient temperatures. The optimum level must be determined relative to other elements of the composition that promote the formation of the alpha phase, such as chromium, or those that promote the formation of the r phase, such as carbon and nitrogen. When the content is equal to or greater than 6%, its effect on structural stability is sufficient. Above 7%, the production cost is excessively increased due to the cost of this added element. Molybdenum enhances pitting resistance. Keys can be added in quantities of up to 6%, as appropriate. Boron is used to improve the forgeability of steel. Depending on the situation, it can be between 0.0005. /. Add the amount of the butterfly to the amount between 0_0025%. Adding a larger amount will significantly reduce the combustion temperature. Sulfur is an element which particularly reduces thermal forgeability and resistance to surnames - its content must be equal to or less than 0.015%. Phosphorus also reduces hot ductility - its content must be less than 〇·〇 45% to obtain satisfactory results. It is an effective reagent for deoxidizing liquid metals. In combination with the above-mentioned hydrazine and the content, the optimum effect is obtained when the content is equal to or less than 〇5〇%. For the manufacture of the two-mechanical properties of the Vostian unrecorded steel, 200951233, the niobium and nitrogen are important elements of the invention. For a given hot rolling end temperature, bismuth retards recrystallization during hot rolling, which is added to maintain a higher work hardening factor (referred to as "work hardening"), thereby enhancing the tensile strength of the steel. . It is similar to ^ and is generally used to prevent the formation of chromium carbide (EN 1 458 〇 and EN i 455 稳定 stabilized Vostian stainless steel). Ultimately, it can result in improved intermetallic phase formation that provides resistance to thermal creep. Nitrogen is a hardening element in the interstitial solid solution and in this respect it most particularly enhances the yield strength. It is also known that in the solid solution, β acts as an effective stabilizer for the Vostian phase and as a retardation agent for the chromium carbide sink. The solubility of nitrogen undergoes a maximum during the solidification - an excessively high content results in the formation of volume defects in the metal. The addition of sharp and nitrogen for the purpose of hardening is not seen in the Worthian stainless steel. In the case of the present invention, stainless steel having a composition close to the composition of 1.4318 steel mentioned above may advantageously benefit from the specific combination of niobium and nitrogen for the purpose of obtaining certain mechanical properties. The specific combination is optimized under certain conditions, as described below: First, 'the nitrogen content is shown to be in the range of 〇.!2% to 〇.16%, while the strontium content is at 〇.15% to 〇31%, the niobium and nitrogen content are as follows. Nb/8 + 0.1% SNb/8 + 0.12% (relationship 1), so that it does not need to be rolled back as in the conventional 1.4318 steel t In the case of fire, it is possible to manufacture a hot rolled sheet having high mechanical properties intended to be stretched, and it is possible that the drawn part is not subjected to the formation of a spiro-like defect. The precipitation of nitride NbN occurring during the end of hot rolling reduces the amount of nitrogen in the solid solution 200951233. After all of the available crucibles were completely precipitated, the above relationship (1) kept the nitrogen in the solid solution vessel as much as the nitrogen in the 14318 grade (N > 0.1%). This thus makes it possible to obtain the same metastability of the Worthfield at ambient temperature. The possibility of reducing the Ni content by increasing the n content is limited by the solubility limit of nitrogen in the steel during solidification. For the Cr, Μ and Ni contents of the steel of the present invention, the nitrogen content must be equal to or less than 0.16%. A sufficient amount of rhenium must be present to achieve hardening and delay recrystallization. This amount is adjusted to obtain a NbN solute above the end temperature of the roll to obtain a precipitate at the end of hot rolling. The niobium and nitrogen content of the present invention enable substantial NbN precipitation to be obtained after hot rolling. 0.15% to 0.31% 铌 (preferably 0.20% to 0.31% sharp) and 0.12% to 〇.16% nitrogen are added in combination, and the nitrogen and nitrogen contents are as follows: training /8 + 〇.1〇/〇< Nb/8 + 0.12%' makes it possible to obtain a favorable yield strength/elongation combination with a product p greater than 21000 MPa.%. With the exception of iron, the remainder of the composition consists of inevitable impurities produced by smelting, such as Sn or Pb. The manufacturing method of the present invention is carried out as follows: A steel having the composition described above is smelted. After this smelting, the steel can then be cast into ingots or, in the most general case, continuously cast in the form of, for example, a plate having a thickness in the range of 150 mm to 250 mm. It is also possible to form a thin plate with a thickness of several tens of millimeters between the steel counter-rotating rolls. First, the scaled semi-finished products are first heated to between (10) and 132.温度 Temperature between 200951233. The purpose of the dirty temperature is to dissolve any sharp foundations (nitrogen compounds and carbonitrides). However, the temperature must be lower than 132 (rc to avoid too close to the solidus temperature that can be achieved in certain isolated areas and to avoid causing the local to begin to exhibit a liquid state that is detrimental to thermoforming. Directly between the counter-rotating rolls In the case of casting a sheet, the step of hot rolling the semi-finished products starting at a temperature below 125 (TC can be carried out directly after casting, so that no intermediate reheating step is required in this case. 辊 Rolling generally includes The rough rolling stand and the finishing stand are carried out on the hot rolling mill. It has been shown that especially by controlling the reduction ratio in the last two finishing stands to obtain a particularly high yield strength Rp〇2: if entering the countdown The thickness of the second finishing stand is expressed as ~_2 and the thickness of the plate exiting the last finishing stand is expressed as eN, then the last 2
e -. eN>2 ~eN 精軋機座之累積縮減比係定義為：—eN·2 。根據本發明， 已表明當輥軋結束溫度低於990°C時且當累積縮減比e大於 ❹ 30%時，所獲得之最終產品之屈服強度RpG.2大於65〇 MPa， 鈮因而完全呈沈澱物形式。 對於介於0.20%與0.31%之間的Nb含量及介於0.12% 與0· 1 6°/〇之間的氮含量而言，當輥軋結束溫度低於97〇乞且 ε大於30%時’獲得此650 MPa最小值。 根據本發明，亦已表明當輥軋結束溫度高於1000〇c 時’有可能獲得具有大於45%之均勻伸長率之熱軋板。在 此狀況下，鈮部分沈澱。 熱軋後’獲得不易受蠕蟲狀缺陷之外觀影響且不需要 11 200951233 中間退火之板。 作為一非限制性實施例’下列結果展示由本發明所賦 予之有利特徵。實施例： 半成品係藉由鑄造具有下表中所提供之組成（以Wt% 計）之鋼來生產： 表1 :鋼之組成（以wt%計） 鋼 C Μη Si Cr Ni Mo S P A1 Nb N η (根據本發明） 0.023 1.100 0.48 17.45 6.67 0.25 0.005 0.020 0.002 0.152 0.13 (根據本發明） 0.024 1.19 0.55 17.36 6.66 0.25 0.005 0.020 0.002 0.302 0.15 R (參考） 0.026 1.030 0.6 17.5 6.6 0.25 0.0008 0.026 0.002 0.002 0.13 加底線之值：不根據本發明 將鋼半成品在1280°C下再加熱30分鐘。接著藉由變化 介於900°C與11〇〇。〇之間的輥軋結束溫度及累積縮減比£ 來進行熱軋操作，以達到3 mm之最終厚度。鋼板ιι_ι、 U-2、l 1-3等表示在不同條件下輥軋相同半成品u所獲得之 板所獲彳于之鋼的微觀結構尤其藉由量測再結晶沃斯田相 之表面分率、所沈澱鈮相對於全部鈮之分率及平均晶粒大 J來表徵。在結構不完全再結晶之狀況下在結構之再結 晶部分上進行後H亦測定拉伸機械性質，尤其屈服 。度RpO·2及均勻伸長率。亦記錄拉伸試驗期間可能存在之 局變形。已知該種局部變形之存在與成形操作期間之螺 12 200951233 蟲狀缺陷之外觀有關。 結果在下表2中給出： 表2:熱軋板之製造條件、微觀結構特徵及機械性質e -. eN>2 ~eN The finishing reduction ratio of the finishing stand is defined as: -eN·2. According to the present invention, it has been shown that when the rolling end temperature is lower than 990 ° C and when the cumulative reduction ratio e is larger than ❹ 30%, the yield strength RpG.2 of the obtained final product is more than 65 MPa, and thus the precipitate is completely precipitated. Form of matter. For a Nb content between 0.20% and 0.31% and a nitrogen content between 0.12% and 0·16°/〇, when the roll end temperature is below 97〇乞 and ε is greater than 30% 'Get this 650 MPa minimum. According to the present invention, it has also been shown that it is possible to obtain a hot rolled sheet having a uniform elongation of more than 45% when the end temperature of the rolling is higher than 1000 〇c. In this case, the hydrazine partially precipitates. After hot rolling, it is not susceptible to the appearance of worm-like defects and does not require 11 200951233 intermediate annealed sheets. As a non-limiting example, the following results demonstrate the advantageous features conferred by the present invention. EXAMPLES: Semi-finished products were produced by casting steel having the composition (in wt%) provided in the following table: Table 1: Composition of steel (in wt%) Steel C Μη Si Cr Ni Mo SP A1 Nb N η (according to the invention) 0.023 1.100 0.48 17.45 6.67 0.25 0.005 0.020 0.002 0.152 0.13 (according to the invention) 0.024 1.19 0.55 17.36 6.66 0.25 0.005 0.020 0.002 0.302 0.15 R (reference) 0.026 1.030 0.6 17.5 6.6 0.25 0.0008 0.026 0.002 0.002 0.13 Bottom line Value: The steel semi-finished product was not heated again at 1280 ° C for 30 minutes according to the invention. Then by varying between 900 ° C and 11 〇〇. The rolling end temperature between the crucibles and the cumulative reduction ratio of £ are hot rolled to achieve a final thickness of 3 mm. The steel plates ιι_ι, U-2, l 1-3, etc. indicate the microstructure of the steel obtained by rolling the same semi-finished product u under different conditions, especially by measuring the surface fraction of the recrystallized Worthfield phase. The precipitated ruthenium is characterized by the fraction of the total ruthenium and the average grain size J. The tensile mechanical properties, especially yield, are also determined after the structural re-crystallization of the structure in the case of incomplete recrystallization of the structure. Degree RpO·2 and uniform elongation. Local deformations that may have occurred during the tensile test were also recorded. It is known that the presence of such local deformation is related to the appearance of the worm-like defect during the forming operation. The results are given in Table 2 below: Table 2: Manufacturing conditions, microstructure characteristics and mechanical properties of hot rolled sheets
試驗 編號 EOR (°C) ε >30% 平均晶粒大小小 於6微米 未再結晶分率介於 30%與70%之間 鈮完全 沈澱 Rp0.2 (MPa) A(%) Rp0.2XA (MPa.%) 局部 變形 11-1 905 是 是 是 是 689 40 27628 否 11-2 935 是 是 是 是 651 40 25520 否 11-3 1040 是 否 否（<30%) 否 432 49 21340 否 11-4 1050 是 否 否（<30%) 否 467 46 21715 否 12-1 930 是 是 是 是 677 38 25997 否 12-2 965 是 是 是 是 681 39 26559 否 12-3 980 否 否 是 是 631 41 26186 否 12-4 1000 否 是 否（<30%) 否 627 46 28277 否 12-5 1100 是 否 否（<30%) 否 547 53 29100 否 R-1 900 是 - 是 一 702 29 20428 是 R-2 925 是 - 是 - 638 29 18566 是 R-3 950 是 - 是 • 632 30 19150 是 R-4 1020 是 - 否（<30%) - 482 31 14749 否 EOR :輥軋結束溫度；Test No. EOR (°C) ε > 30% Average grain size less than 6 microns No recrystallization fraction between 30% and 70% 铌 Complete precipitation Rp0.2 (MPa) A(%) Rp0.2XA ( MPa.%) Local deformation 11-1 905 Yes Yes Yes 689 40 27628 No 11-2 935 Yes Yes Yes 651 40 25520 No 11-3 1040 No (<30%) No 432 49 21340 No 11-4 1050 No (<30%) No 467 46 21715 No 12-1 930 Yes Yes Yes 677 38 25997 No 12-2 965 Yes Yes Yes 681 39 26559 No 12-3 980 No No Yes Yes 631 41 26186 No 12-4 1000 No (<30%) No 627 46 28277 No 12-5 1100 No (<30%) No 547 53 29100 No R-1 900 Yes - Yes One 702 29 20428 Yes R-2 925 Yes - Yes - 638 29 18566 Yes R-3 950 Yes - Yes • 632 30 19150 Yes R-4 1020 Yes - No (<30%) - 482 31 14749 No EOR : Rolling end temperature;
Rpo.2 : 0.2%應力下之習知屈服強度； A :均勻伸長率； ε :最後2個輥軋通過之累積縮減比。 因此，上表展示本發明之鋼11及12具有大於21000 MPa.%之尤其有利之乘積Rp〇.2xA，然而不管輥軋條件如 何，參考R鋼不具有該種乘積。 13 200951233 此表亦展示當未再結晶分率介於3〇%與7〇%之間時且 當平均晶粒大小小於6微米時，屈服強度RpQ 2大於65〇 Mpa (試驗11·1、11-2、12_i、12_2)<)此外，當未再結晶分率大 於70%時，伸長率趨於降低。 獲得具有下列各特徵之鋼的此等特性：說含量介於 0.15%與0.31 %之間；且氮含量介於〇 12%與〇 16%之間； 鈮及氮含量係如下：Nb/8 + 0.1% sn SNb/8 + 0.12% ;輥軋 結束溫度低於990。(：；且累積縮減比ε大於3〇%。 在鋼具有介於0.20%與〇·31%之間的鈮含量及介於 0.12%與0.16%之間的氮含量之狀況下，鈮及氮含量係如 下：Nb/8 + 0.1% <Nb/8 + 〇 12%，此等特性可在輥軋結 束溫度低於970°C且在累積縮減比ε大於3〇%時獲得（試驗 12-1 及 12-2)。 當銳不完全沈澱（試驗ιι·3、η_4、12 4、12 5)時， 均勻伸長率大於45%。對於本發明之鋼組成而言，當輥軋 結束溫度高於1000t時獲得此結果。相比而言，參考鋼不 提供該等性質。 因此，某些製造條件（輥軋結束溫度及累積縮減比） 應更尤其視需要生產具有尤其高之屈服強度之鋼板還是需 要生產具有高伸長能力之鋼板來選擇。 此外，無論為何種熱軋條件，本發明之鋼之應力_應變 曲線均未展示指示局部變形之平台’與當部分再結晶時即 展現局部變形之參考鋼（試驗R·〗、r_2、R_3 )形成對比。 此點藉由確保不存在端蟲狀缺陷而對成形操作尤其有利。 200951233 因此，本發明之熱軋鋼板由於其尤_ .田人丹尤其尚之機械性質且 尤其其極有利之屈服強度與均勻伸長率之乘積而有利地用 於需要良好可成形性及高耐蝕性之應用。當其用於汽車行 業中時，可有利益地享有其對於結構組件之經濟製142的優 勢。 【圖式簡單說明】 無 m 【主要元件符號說明】 無Rpo.2: conventional yield strength at 0.2% stress; A: uniform elongation; ε: cumulative reduction ratio of the last 2 rolls. Thus, the above table shows that the steels 11 and 12 of the present invention have a particularly advantageous product Rp 〇 2xA of more than 21,000 MPa.%, however, regardless of the rolling conditions, the reference R steel does not have such a product. 13 200951233 This table also shows that when the non-recrystallization fraction is between 3〇% and 7〇% and when the average grain size is less than 6 microns, the yield strength RpQ 2 is greater than 65〇Mpa (Tests 11.1, 11) -2, 12_i, 12_2) <) Further, when the non-recrystallization fraction is more than 70%, the elongation tends to decrease. Obtaining such characteristics of steel having the following characteristics: said content is between 0.15% and 0.31%; and nitrogen content is between 〇12% and 〇16%; 铌 and nitrogen content are as follows: Nb/8 + 0.1% sn SNb/8 + 0.12%; the rolling end temperature is below 990. (:; and the cumulative reduction ratio ε is greater than 3〇%. In the case where the steel has a niobium content between 0.20% and 〇·31% and a nitrogen content between 0.12% and 0.16%, niobium and nitrogen The content is as follows: Nb / 8 + 0.1% < Nb / 8 + 〇 12%, these characteristics can be obtained at the end of the rolling temperature below 970 ° C and when the cumulative reduction ratio ε is greater than 3〇% (Test 12- 1 and 12-2). When the sharpness is not completely precipitated (test ι, 3, η_4, 12 4, 12 5), the uniform elongation is greater than 45%. For the steel composition of the present invention, when the rolling end temperature is high This result is obtained at 1000 t. In contrast, the reference steel does not provide these properties. Therefore, certain manufacturing conditions (rolling end temperature and cumulative reduction ratio) should be more particularly required to produce steel sheets with particularly high yield strength. It is still necessary to produce a steel sheet having a high elongation capability. Further, regardless of the hot rolling conditions, the stress-strain curve of the steel of the present invention does not show a platform indicating local deformation and a local deformation when partially recrystallized. Reference steel (test R·〗, r_2, R_3) is used for comparison. The absence of worm-like defects is particularly advantageous for forming operations. 200951233 Therefore, the hot-rolled steel sheet of the present invention is advantageous in that it is particularly advantageous in terms of its mechanical properties and especially its multiplicative yield strength and uniform elongation. It is used in applications that require good formability and high corrosion resistance. When it is used in the automotive industry, it can benefit from its economical advantages of structural components. 142 [Simple diagram] No m [Main Component symbol description]
1515