200944598 九、發明說明： 【發明所屬之技術領域】 本發明是有關於一種鋼材，特別是指一種具有良好強 度及加工性質的熱軋鋼材以及其製法。 【先前技術】 鋼材的應用領域相當廣泛，例如汽車、家電、機械、 建築等皆必須使用鋼材，所以鋼材的強度及加工性也需因 應各個領域的不同而進行調整。以汽車用鋼材來說，相較 ❹ 於其他領域，在其生產的過程中，需經過更繁雜的成型加 工，所以汽車用鋼材除了強度的要求之外，其加工性（伸長 率、擴孔性等）要求亦有所規範，更讓高強度汽車用鋼材成 為目前業界爭相發展的目標之一。 目岫咼強度汽車用鋼材的開發，大多朝向晶粒細化來 發展。通常欲獲得晶粒低於5 μπι以下的晶粒，較常使用的 方式是採用相變化來達成，例如添加鉬 '硼等元素來產生 變韌鐵相變化’但是結果發現，以變韌鐵為主要顯微組織 ® 之鋼材的伸長率不佳’所以於常溫下不易加工成型，因此 ’冷加工成型的高強度鋼材目前多數轉為以肥粒鐵為主要 相的方向進行發展》 現有以肥粒鐵為主要相之冷加工成型高強度鋼材，以 雙相鋼（dual-phase steel)最為著名，雙相鋼主要是藉由軋延 時之冷卻控制，而在肥粒鐵的基相中散佈著1〇〜30%的麻田 散鐵，此雙相鋼的抗拉強度為300 MPa〜900 MPa，但於實 際使用時發現，當麻田散鐵等低溫相變化產物的含量越多 5 200944598 、 時，雖然可有效增加強度，但卻會致使加工性變差，所以 ，雙相鋼需運用階段冷卻方式來控制鋼材中之麻田散鐵的 量’以取得符合後續應用之強度及加工性，而所謂的階段 冷卻方式對於熱軋的連續軋延、冷卻及盤捲製程而言，階 段冷卻的控制相當不易，通常無法取得符合業界要求的加 工性。 於曰本川崎製鐵所擁有的TW 473549專利中，提及一 種具有超細微粒之加工用熱軋鋼板，該鋼板含有〇〇1〜〇3 ❹ wt°/o的碳、〇.〇3〜0.3 wt°/〇的鈦、2.0 wt%以下的矽及〇 5 wt〇/0 以下的磷’其製作方法是將鋼胚再加熱至U5〇〇c以下，接 著進行熱軋製’在此熱軋製過程中，於沃斯田鐵之動態再 結晶溫度之低溫區域内，至少進行3次軋製以上的輕微壓 下，再於軋製結束後2秒内，以30°C/sec以上的冷卻速度 進行冷卻，最後於350〜550〇C之溫度下進行捲繞。在此專 利中’主要是透過較低的再熱溫度（1150°C以下）以及在低 溫下控制壓下率為13〜30%，以獲得微細化的晶粒組織，且 ® 所獲得之鋼材的抗拉強度為520〜763 MPa以及降伏強度為 420〜629 MPa。雖然此專利成功取得微細化的晶粒組織，但 是，此專利之鋼板的製程於實際應用時，卻發現有不易操 作（例如需要特別控制壓下率及壓下時間）等問題。 由此可知，如能在使用一般軋延機之簡單製程下，有 效地讓晶粒微細化，同時取得高強度且易於加工之熱軋鋼 材，應可讓鋼材的應用發揮至極致。 【發明内容】 6 200944598 因此，本發明之目的，即在提供一種易於加工的高強 度熱軋鋼材。 本發明另提供一種用於製備上述高強度熱軋鋼材的方 法。 於疋’本發明之咼強度熱軋鋼材，以其總重為丨〇〇 wt〇/。 计算，包含以下成份：0.01〜0 25 wt%的碳、〇 5〇〜3 〇〇 的錳、0.01 〜0.30 wt% 的矽、〇〇〇1〜〇〇2〇 wt% 的磷、 0.0006〜〇_〇2 wt%的硫、〇.05〜〇·3〇 wt%的鈦、〇 〇〇2〇〜〇 〇15〇 _ Wt/°的氮、0 01〜0·3 wt%的鋁，以及平衡量的鐵及不顯著之 雜質’其中，鈦與氮的含量比例大於3·42，且該鋼材的顯 微結構包含一比率為90%以上的肥粒鐵相及一高碳相，該 肥粒鐵相的粒徑為2〜5 μηι並具有複數分散於該肥粒鐵相中 的析出物，該等析出物含有粒徑為2〇 nm以下的碳化物以 及粒控為0.5〜5 μπι的氮化物。 本發明之高強度熱軋鋼材的製備方法，包含之步驟為 :使一鋼胚加熱至115〇。^以上的溫度，以獲得一經加熱之 ® 鋼胚，其中該鋼胚含有0·01〜ο.25 wt0/。的碳、〇·5〇〜3.00 wt% 的猛、〇.01 〜〇.30 wt% 的矽、0.001 〜0.020 wt% 的磷、 0.0006〜0.02 wt0/。的硫、0 〇5〜〇 3〇 wt%的鈦、〇 〇〇2〇〜〇 〇15〇 wt%的氮、〇.〇1〜〇.3 wt%的鋁，以及平衡量的鐵及不顯著之 雜質且欽與氮的含量比例大於3.42 ;使該經加熱之鋼胚 進打熱札步驟’並將完軋溫度控制為Αγ3溫度以上（Ar3溫 度是指冷卻過程中沃斯田鐵開始變態成肥粒鐵的起始溫度 ’可以由膨服儀量測或由公式計算得到，此處將完軋溫度 200944598 控制為Ar3溫度以上是指在沃斯田鐵相完成熱軋延），以獲 得一完軋鋼材；及使該完軋鋼材進行冷卻步驟，而於 480〜680 °C的溫度下進行盤捲，以製得該熱軋鋼材。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steel material, and more particularly to a hot rolled steel material having good strength and processing properties and a process for producing the same. [Prior Art] Steel is widely used in applications such as automobiles, home appliances, machinery, and construction. Therefore, the strength and workability of steels must be adjusted in accordance with various fields. In the case of automotive steel, it is more complicated than other fields in the production process. Therefore, in addition to the strength requirements of automotive steel, its workability (elongation, hole expandability) Etc.) The requirements are also regulated, and the high-strength automotive steel has become one of the goals of the industry. The development of the steel for the purpose of the development of the steel is mostly developed toward grain refinement. Usually, it is necessary to obtain crystal grains with crystal grains below 5 μπι. The more commonly used method is to use phase change, for example, adding molybdenum 'boron and other elements to produce a tough iron phase change'. However, it is found that the toughened iron is The main microstructure® steel has poor elongation. Therefore, it is difficult to form and mold at room temperature. Therefore, most of the cold-formed high-strength steels are currently developed in the direction of ferrite iron as the main phase. For the main processing of cold-formed high-strength steel, the most famous is the dual-phase steel. The dual-phase steel is mainly controlled by the cooling of the rolling delay, and is dispersed in the base phase of the ferrite iron. 30% of the granulated iron, the tensile strength of the duplex steel is 300 MPa~900 MPa, but in actual use, it is found that when the content of the low temperature phase change product such as 麻田散铁 is 5 200944598, it is effective. Increasing the strength, but it will cause the workability to deteriorate. Therefore, the dual-phase steel needs to use the stage cooling method to control the amount of the loose iron in the steel in order to obtain the strength and processability according to the subsequent application. That the cooling phase of continuous hot rolling and rolling, coiling and cooling process, the cooling stage is quite difficult to control, often can not meet the industry to obtain processability requirements. In the TW 473549 patent owned by Sakamoto Kawasaki Steel, a hot-rolled steel sheet for processing with ultrafine particles containing 〇〇1 to 〇3 ❹ wt°/o of carbon, 〇.〇3~ is mentioned. 0.3 wt ° / 〇 titanium, 2.0 wt% or less 矽 and 〇 5 wt 〇 / 0 or less phosphorus ' is produced by reheating the steel embryo to below U5 〇〇 c, followed by hot rolling 'hot here During the rolling process, in the low temperature region of the dynamic recrystallization temperature of the Worthite iron, at least three times of rolling and rolling are performed, and then, within 2 seconds after the end of rolling, 30 ° C/sec or more. The cooling rate is cooled, and finally coiled at a temperature of 350 to 550 °C. In this patent, 'mainly through a lower reheat temperature (below 1150 ° C) and at a low temperature to control the reduction rate of 13 to 30% to obtain a fine grain structure, and the steel obtained by the ® The tensile strength is 520 to 763 MPa and the lodging strength is 420 to 629 MPa. Although this patent succeeded in obtaining a fine grain structure, the process of the steel plate of this patent was found to be difficult to handle (e.g., special control of the reduction ratio and the pressing time). From this, it can be seen that, in the simple process using a general rolling mill, it is possible to make the grain finer and at the same time obtain a high-strength and easy-to-process hot-rolled steel, and the application of the steel should be maximized. SUMMARY OF THE INVENTION 6 200944598 Accordingly, it is an object of the present invention to provide a high strength hot rolled steel material which is easy to process. The present invention further provides a method for preparing the above high strength hot rolled steel.于疋' The strength of the hot-rolled steel of the present invention is 丨〇〇wt〇/. Calculated, including the following components: 0.01~0 25 wt% carbon, 〇5〇~3 〇〇 manganese, 0.01~0.30 wt% 矽, 〇〇〇1~〇〇2〇wt% phosphorus, 0.0006~〇 _〇2 wt% sulfur, 〇.05~〇·3〇wt% of titanium, 〇〇〇2〇~〇〇15〇_ Wt/° of nitrogen, 0 01~0·3 wt% of aluminum, and A balanced amount of iron and insignificant impurities' wherein the ratio of titanium to nitrogen is greater than 3.42, and the microstructure of the steel comprises a ferrite phase of a ratio of more than 90% and a high carbon phase, the fertilizer The granular iron phase has a particle diameter of 2 to 5 μηι and has a plurality of precipitates dispersed in the ferrite iron phase, and the precipitates contain carbides having a particle diameter of 2 nm or less and a particle size of 0.5 to 5 μm. nitride. The method for preparing a high-strength hot-rolled steel material according to the present invention comprises the steps of: heating a steel slab to 115 Torr. ^ Above the temperature to obtain a heated ® steel embryo, wherein the steel embryo contains 0·01~ο.25 wt0/. The carbon, 〇·5〇~3.00 wt% 猛, 〇.01 〇.30 wt% 矽, 0.001 ～0.020 wt% phosphorus, 0.0006~0.02 wt0/. Sulfur, 0 〇5~〇3〇wt% of titanium, 〇〇〇2〇~〇〇15〇wt% of nitrogen, 〇.〇1~〇.3 wt% of aluminum, and balance of iron and no Significant impurities and the content ratio of Qin to nitrogen is greater than 3.42; the heated steel embryo is subjected to the hot step and the rolling temperature is controlled to be above the Αγ3 temperature (Ar3 temperature means that the Worth iron begins to metamorphose during the cooling process) The initial temperature of the fermented iron can be measured by the expansion apparatus or calculated by the formula. Here, the control of the rolling temperature 200944598 to the temperature above Ar3 means that the iron phase in the Vostian iron phase is completed. After the rolling of the steel material is completed; and the finished steel material is subjected to a cooling step, coiling is performed at a temperature of 480 to 680 ° C to obtain the hot rolled steel material.
本發明之高強度熱軋鋼材除了控制鈦與氮的含量比例 大於3 _42以及各個成份的含量比例之外，更藉由使肥粒鐵 主相的晶粒微細化，同時讓肥粒鐵主相中分佈較多量且均 勻之奈米級碳化物’使得熱軋鋼材的強度（特別是降伏強度 及抗拉強度）得以提昇。而上述顯微結構’主要是透過本發 明的特殊製備方法所達成，經由適當控制鋼胚中之成份含 量、製程中之再加熱溫度（115MC以上）以及盤捲溫度 (480〜680°C) ’使得肥粒鐵主相的晶粒微細化，且於盤捲過 程中透過適當的盤捲溫度，使奈米級碳化物被大量析出， 藉以提昇鋼板之強度（例如抗拉強度高於7〇〇 Mpa，降伏強 度高於650 MPa)。 【實施方式】 於本發明之高強度熱軋鋼材的顯微結構中，該肥粒鐵 相的比率為 90%以上，赫社4J* ^ 干π川/〇 Μ上較佳地，該肥粒鐵相的比率為 90〜99%，該高碳相的比例為丨〜忉％。 較佳地，該高碳相是選自於雪明碳鐵、波來鐵、㈣ 鐵、麻田散鐵或此等之一組合；更佳地，該高碳相為雪明 碳鐵。 农场肥粒鐵相之析出物中，該粒徑為2〇細以下的碳 化物可增加鋼材的強度，而該粒獲為〇5〜5μιη的氮化物由 於析出物尺寸較大，可有效抑制高溫沃斯田鐵晶粒成長， 8 200944598 使;天斯田鐵於完軋之後續冷卻過程，形成晶粒微細化的肥 粒鐵相。於盤捲過程中，因為鋼捲冷速很慢，將產生大量 奈米尺寸碟化物析出物’較佳地，該碳化物的粒徑為5〜20 nm ’更佳地’該碳化物的粒徑為5〜15 nm。 本發明之高強度熱軋鋼材所含有的成份需包含 0·01〜〇·25 wt%的碳、〇.5〇〜3.00 wt%的錳、〇.〇1 〜〇.3〇 wt%的 石夕、0.001 〜〇·020 wt% 的磷、〇 〇〇〇6〜〇 〇2 wt% 的硫、 〇.05〜〇.30 wt% 的鈦、0.0020〜0.0150 wt% 的氮、〇.〇1 〜0.3 ❹ Wt%的鋁，以及平衡量的鐵及不顯著之雜質，且鈦與氮的含 量比例需大於3.42(即Ti/N> 3.42)。較佳地，該鋼材更包含 一合金成份’該合金成份是選自於〇 〇2〜〇 2 wt%的釩、 0·05〜0·3 wt%的鉻或兩者之一組合。 上述提及的各個成份分別具有不同的作用，於本發明 中，除了碳、矽、錳、鈦、鋁、磷、硫及氮為主要成份之 外’其餘成份可依據實際需要進行挑選。以下將分別說明 各種成份及其含量比例對於本發明之高強度鋼材的影響： ® 碳：為鋼材中重要的強化元素，且於本發明中，碳是決定 奈米析出物的重要元素’當碳含量太低時’析出物不 易生成，當碳含量太高時，則析出物容易粗化，使得 鋼材強度太強’也可能會使鋼材的硬化能提高而容易 產生變初鐵或麻田散鐵’而使得該鋼材的伸長率降低 ，所以本發明的碳含量需控制在0.01〜0.25 wt%。 猛：為鋼材中重要的固溶強化元素，於本發明中是用來提 高鋼材強度，但當錳含量太高時，會使鋼材的成型性 9 200944598 不佳。 氮：為固溶強化元素’且氮與欽的結合性很好在超過 1400 c以上的咼溫就會開始形成氮化鈦（ΤίΝ)。本發明 主要藉由TiN的生成，並運用TiN的高溫穩定性，而 於熱軋加熱爐内可阻止沃斯田鐵晶粒的過度成長。但 是當氮含量太高時會造成TiN過度粗化’同時也會成 為破壞起始源，因此，本發明的氮含量需控制在 0.0020〜0.0150 wt% 〇 〇 欽$常用的析出強化元素’在本發明中，除了於高溫產 生TiN外，鈦添加的目的是希望在喷水冷卻之熱軋盤 捲過程中，產生碳化鈦（Tic)析出。在本發明中， >3.42，因此鈦的過飽和度很高，所以可在短時間内大 量成核產生耷米級析出物，而達到析出強化的目的。 不過，當鈦的添加量太高時，將會致使所析出的碳化 鈦粗化，同時讓析出強化效果下降，因此，本發明的 鈦含量需控制在〇.〇5〜〇.30 wt%。 # 石夕：為固溶強化元素，♦可延遲雪明碳鐵的析出，使得過 飽和的碳得以產生大量奈米級析出物。當添加不足時 無法得到上述效果，所以矽的最少添加量為〇〇1糾％ 。但添加過量會產生帶狀紅銹，影響外觀，故矽的上 限為 0.30 wt%。 ^屬於鋼材中的不純物，容易偏析至晶界，造成晶界脆 化，因此需將磷含量控制在〇.〇2 wt%以下，當磷含量 過高時，容易造成熱軋延時的邊裂，且產品在使用時 10 200944598 也會產生脆性問題。 硫：屬於鋼材中的不純物’在高溫時可能產生那、扎以2 ” MnS ’其中’ TiS、Ti4C2S2會消耗所添加的鈦，而 MnS又軋延後會呈長條狀，成為破壞起始源所以硫 含量需控制在0.0006〜〇.〇2 wt%。 鈒為常用的析出強化元素，冑添力〇適量飢時，將可延後 Tic析出物的粗A，使得Tic可保持奈钱尺寸且可大 量分散於肥粒鐵相中。但是當鈒含量太高時，也容易 參 讓析出物粗化，所以其含量需控制在0·02〜0.2wt%。 鉻：為提高鋼材硬化能與提昇耐蝕性的重要元素，同時也 疋析出強化兀素，添加鉻的目的是藉由鉻與碳有良好 的親和性，以延遲雪明碳鐵之析出。 鋁.主要用來作為煉鋼時進行脫氧，當鋁含量低於〇 時，將造成脫氧不足，而當含量高於〇3時， 將影響成型性。 於本發明之製備方法中，該鋼胚的製作方式可依據一 ❹麟煉製程進行，例如制適當含量的元素成份與鐵進行 熔煉後，再予以造塊或連鑄成鋼胚。該鋼胚所含的成份， 除了碳、鐘、石夕、磷、硫、鈦、铭及氮之外，較佳地該 鋼胚更含有-合金成份，該合金成份是選自於Q 2 4In addition to controlling the content ratio of titanium to nitrogen and the content ratio of each component, the high-strength hot-rolled steel of the present invention further refines the grain of the main phase of the ferrite grain iron while allowing the main phase of the ferrite grain iron The distribution of a large amount of uniform nano-carbonized carbides improves the strength (especially the strength of the fall and the tensile strength) of the hot-rolled steel. The above microstructure is mainly achieved by the special preparation method of the present invention, by appropriately controlling the content of the components in the steel preform, the reheating temperature in the process (above 115MC), and the coiling temperature (480 to 680 ° C). The grain of the main phase of the ferrite grain iron is refined, and the nano-scale carbide is precipitated in a large amount by the appropriate coiling temperature during the coiling process, thereby increasing the strength of the steel sheet (for example, the tensile strength is higher than 7〇〇). Mpa, the drop strength is higher than 650 MPa). [Embodiment] In the microstructure of the high-strength hot-rolled steel material of the present invention, the ratio of the ferrite-grain iron phase is 90% or more, and it is preferable that the Hesi 4J*^ dry π Chuan/〇Μ The ratio of the iron phase is 90 to 99%, and the ratio of the high carbon phase is 丨~忉%. Preferably, the high carbon phase is selected from the group consisting of ferritic carbon, ferrite, (iv) iron, 麻田散铁 or a combination thereof; more preferably, the high carbon phase is ferritic carbon iron. In the precipitate of the ferrite phase of the farm, the carbide having a particle size of 2 Å or less can increase the strength of the steel, and the nitride obtained as 〇5 to 5 μm is highly effective in suppressing the high temperature due to the large precipitate size. Worthfield iron grain growth, 8 200944598; Tianstian Iron in the subsequent cooling process, the formation of fine grained ferrite grain iron phase. During the coiling process, because the steel coil has a very slow cooling rate, a large amount of nano-sized disc precursors will be produced. Preferably, the carbide has a particle size of 5 to 20 nm. More preferably, the carbide particles. The diameter is 5 to 15 nm. The high-strength hot-rolled steel of the present invention contains a component containing 0·01 〇·25 wt% of carbon, 〇.5 〇~3.00 wt% of manganese, 〇.〇1 〇.3〇wt% of stone.夕, 0.001 ~ 〇 · 020 wt% of phosphorus, 〇〇〇〇6~〇〇2 wt% of sulfur, 〇.05~〇.30 wt% of titanium, 0.0020~0.0150 wt% of nitrogen, 〇.〇1 ~0.3 ❹ Wt% of aluminum, as well as a balanced amount of iron and insignificant impurities, and the ratio of titanium to nitrogen needs to be greater than 3.42 (ie Ti/N> 3.42). Preferably, the steel material further comprises an alloy composition. The alloy composition is selected from the group consisting of ruthenium 2 〇 2 wt% vanadium, 0. 05 〜 0·3 wt% chromium or a combination of the two. Each of the above-mentioned components has a different function. In the present invention, except for carbon, germanium, manganese, titanium, aluminum, phosphorus, sulfur and nitrogen as main components, the remaining components can be selected according to actual needs. The effects of various components and their content ratios on the high-strength steel of the present invention will be separately described below: ® carbon: an important strengthening element in the steel, and in the present invention, carbon is an important element determining the nano-precipitate 'when carbon When the content is too low, the precipitates are not easily formed. When the carbon content is too high, the precipitates are easily coarsened, so that the strength of the steel is too strong, and the hardening energy of the steel may be increased to easily produce the initial iron or the granulated iron. The elongation of the steel material is lowered, so the carbon content of the present invention is controlled to be 0.01 to 0.25 wt%. Meng: It is an important solid solution strengthening element in steel. It is used to improve the strength of steel in the present invention, but when the manganese content is too high, the formability of the steel is not good. Nitrogen: is a solid solution strengthening element' and the combination of nitrogen and chin is very good. At temperatures above 1400 c, titanium nitride (开始ίΝ) begins to form. The present invention mainly utilizes the formation of TiN and utilizes the high temperature stability of TiN, and the excessive growth of the iron grains of the Worthfield can be prevented in the hot rolling furnace. However, when the nitrogen content is too high, the TiN is excessively coarsened, which also becomes the source of destruction. Therefore, the nitrogen content of the present invention needs to be controlled at 0.0020 to 0.0150 wt%. In the invention, in addition to the generation of TiN at a high temperature, the purpose of the addition of titanium is to produce titanium carbide (Tic) precipitation during hot-rolling coiling of water spray cooling. In the present invention, > 3.42, therefore, the degree of supersaturation of titanium is high, so that a large amount of nucleation can be produced in a short time to produce a glutinous precipitate, and the purpose of precipitation strengthening is achieved. However, when the amount of titanium added is too high, the precipitated titanium carbide is coarsened and the precipitation strengthening effect is lowered. Therefore, the titanium content of the present invention is controlled to be 〇. 5 to 〇 30% by weight. #石夕: For solid solution strengthening elements, ♦ can delay the precipitation of ferritic carbon iron, so that the supersaturated carbon can produce a large number of nano-scale precipitates. When the addition is insufficient, the above effect cannot be obtained, so the minimum addition amount of 矽 is 〇〇1 correction%. However, excessive addition will cause band red rust, which will affect the appearance, so the upper limit of bismuth is 0.30 wt%. ^ is an impurity in the steel, easy to segregate to the grain boundary, causing grain boundary embrittlement, so the phosphorus content should be controlled below 〇. 〇 2 wt%, when the phosphorus content is too high, it is easy to cause edge cracking of hot rolling delay, And when the product is in use, 200944598 will also have brittle problems. Sulfur: It belongs to the impurity in steel. 'It may be produced at high temperature, and it is 2" MnS 'where 'TiS, Ti4C2S2 will consume the added titanium, and MnS will be elongated after rolling, which is the starting source of damage. Therefore, the sulfur content should be controlled at 0.0006~〇.〇2 wt%. 鈒 is a commonly used precipitation strengthening element, and when it is suitable for hunger, it will delay the coarse A of the Tic precipitate, so that Tic can maintain the size of the money. It can be dispersed in a large amount of iron in the ferrite. However, when the content of niobium is too high, it is easy to coarsen the precipitate, so its content should be controlled at 0. 02~0.2wt%. Chromium: To improve the hardening and upgrading of steel An important element of corrosion resistance, but also the strengthening of bismuth. The purpose of adding chromium is to delay the precipitation of ferritic carbon iron by the good affinity of chromium and carbon. Aluminum is mainly used for deoxidation during steelmaking. When the aluminum content is lower than 〇, it will cause insufficient deoxidation, and when the content is higher than 〇3, the moldability will be affected. In the preparation method of the present invention, the steel embryo can be produced according to a unicorn refining process. , for example, to make an appropriate amount of elemental ingredients After the iron is smelted, it is then agglomerated or continuously cast into a steel embryo. The composition of the steel embryo, in addition to carbon, bell, stone, phosphorus, sulfur, titanium, indium and nitrogen, preferably the steel embryo More containing - alloy composition, the alloy composition is selected from Q 2 4
的釩、0.05〜0.3 wt%的鉻或兩者之一組合D 接著，使該鋼胚再加熱至1150cC以上的溫度，此步驟 主要是為了在後續冷卻盤捲步驟中產生奈米析出物，所以 先將該鋼胚放置於-再加熱爐巾，並將再加熱溫度控制在 11 200944598 1150°C以上，使得TiN以外之其他析出物（如Tic)可再固溶 回去，以在後續冷卻盤捲的步驟中，可重新析出奈米級Tic 。較佳地，該再加熱溫度控制為1150〜1300〇c。 於該將加熱之鋼胚的熱軋步驟中，可運用一般軋延機 進行熱軋且該完軋溫度需控制在Ar3溫度以上，原因在於 當完軋溫度低於Ar3溫度時，熱軋步驟將會在兩相區中進 行，使得肥粒鐵相提早生成而導致肥粒鐵相的晶粒產生粗 化現象’以致無法獲得微米級肥粒鐵相晶粒，因此，該完 ❹ 軋溫度需為Ar3溫度以上。較佳地，該完軋溫度範圍是介 於Ar3溫度至950°C之間。 在該完軋鋼材的冷卻步驟中，較佳地，完軋後的完軋 鋼材以20°C/sec的冷卻速率進行快速冷卻，以避免軋延所 產生的缺陷被回復，同時可降低肥粒鐵的變態溫度，而有 助於獲得2〜5 μπι的肥粒鐵晶粒。此外，該盤捲溫度需控制 在480〜680°C，原因在於此溫度範圍是Tic在肥粒鐵相中的 主要析出溫度，所以在此溫度範圍進行盤捲後，可運用盤 〇 捲後緩慢地冷卻，使TiC有足夠的時間大量析出，同時藉 由其他成份來避免析出物過度成長，因而可獲得2〇 nm以 下的碳化物。 使用本發明之製備方法，可成功地使該熱軋鋼材包含 90%以上的肥粒鐵相，該肥粒鐵相的粒徑為2〜5 μιη並具有 粒徑為20 nm以下的碳化物及粒徑為〇 5〜5 μιη的氮化物。 本發明將就以下實施例來作進一步說明，但應瞭解的 是’該實施例僅為例示說明之用，而不應被解釋為本發明 12 200944598 實施之限制。 <實施例> ί實施例1〜6】 依據下表1的成份進行調配，再分別預先進行真空 溶煉並洗鑄製作取得一鋼胚，接著，依據下表】的再加熱 =度（SRT)’使該鋼胚於—高溫爐中進行加熱以分別獲 得一經加熱之鋼胚。使該經加熱之鋼胚於一軋延機中進行 熱軋步驟’再依據表丨的完軋溫度（FT)，將該經加熱之鋼 〇 胚軋延至4.5 mm，以分別獲得一完軋鋼材。然後依據表 1的盤捲溫度（ct)，使該完軋鋼材進行冷卻步驟’最後分 別製得實施例1〜6的熱乳鋼材。 [比較例1~3】 同樣依據下表1以及上述實施例1〜6的製作過程， 最後製得比較例1〜3的熱軋鋼材。 ❹ 13 200944598 表1 編號 實施例 比較例 1 2 3 4 5 6 1 2 3 成 份 C 0.08 0.08 0.12 0.08 0.12 0.08 0.12 0.10 0.12 Μη 1.53 1.55 1.52 1.53 1.51 1.50 1.51 1.50 1.50 Ti 0.14 0.15 0.14 0.18 0.18 0.12 0.18 0.09 0.04 V 0.04 0.04 0.04 0.04 0.04 a 0.04 - 0.03 Cr - 0.16 - 0.16 - 0.18 - 0.20 - Nb 0.03 - Si 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03 P 0.01 0.01 0.01 0.01 0,01 0.01 0.01 (KOI 0.01 S 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 N 0.004 0.004 0.004 0.004 0.004 0.004 0.004 0.004 0.004 熱 軋 參 數 SRTb 1170 1170 1200 1220 1170 1170 1170 1100 1150 FTC 900 900 880 900 910 860 950 965 900 CTd 550 550 570 550 550 520 450 450 500 a. 表示未添加。 b. SRT表示再加熱溫度（°C)。 c. FT表示完軋溫度（°C)。 d. CT表示盤捲溫度（°C)。 【測試】上述實施例及比較例分別針對以下性質進行測試： 1 · 降伏強度（yield strength，以下簡稱為「ys」）：依 據標準方法CNS 2112，G2014進行測試，單位為Mpa 〇 2. 抗拉強度（tensile strength，以下簡稱為「TS」）· 14 200944598 依據標準方法CNS 2112,G2014進行測試，單位為 MPa 〇 3. 伸長率（elongation，以下簡稱為「E1%」）：依據標 準方法CNS 2112,G2014進行測試。 上述實施例1〜6及比較例1〜3的測試結果如下表2 編號 實施例 比較例 1 2 3 4 5 6 1 2 3 YS 735 778 717 720 695 717 622 63Q 545 TS 777 807 758 795 745 747 685 656 632 EI 26 23 26 23 28 22 24 23 27Vanadium, 0.05~0.3 wt% chromium or a combination of the two. D. The steel embryo is reheated to a temperature above 1150 cC. This step is mainly for the production of nano precipitates in the subsequent cooling coiling step, so The steel embryo is first placed in a reheating towel, and the reheating temperature is controlled above 11 200944598 1150 ° C, so that other precipitates other than TiN (such as Tic) can be re-dissolved back to the subsequent cooling coil. In the step, the nano-scale Tic can be re-extracted. Preferably, the reheating temperature is controlled to be 1150 to 1300 〇c. In the hot rolling step of the steel preform to be heated, the general rolling mill can be used for hot rolling and the rolling temperature should be controlled above the Ar3 temperature, because when the rolling temperature is lower than the Ar3 temperature, the hot rolling step will be Will be carried out in the two-phase zone, so that the ferrite grain iron phase is formed early and the grain of the ferrite grain iron phase is coarsened. Thus, the micron-sized ferrite grain phase grain cannot be obtained. Therefore, the finish rolling temperature needs to be Above Ar3 temperature. Preferably, the finishing temperature ranges from between Ar3 and 950 °C. In the cooling step of the finished steel material, preferably, the finished rolled steel material is rapidly cooled at a cooling rate of 20 ° C / sec to avoid the defects generated by the rolling and being recovered, and at the same time, the fertilizer particles can be reduced. The metamorphic temperature of iron helps to obtain iron grains of 2~5 μπι. In addition, the coil temperature should be controlled at 480~680 °C, because the temperature range is the main precipitation temperature of Tic in the ferrite grain iron phase, so after coiling in this temperature range, it can be used slowly after coiling. The ground cooling causes the TiC to have a sufficient amount of time to precipitate, and at the same time, the precipitates are prevented from excessive growth by other components, so that carbides of 2 nm or less can be obtained. By using the preparation method of the present invention, the hot-rolled steel material can be successfully contained in an iron phase of 90% or more, and the iron phase of the ferrite is 2 to 5 μm and has a carbide having a particle diameter of 20 nm or less. A nitride having a particle diameter of 〇5 to 5 μηη. The invention will be further illustrated by the following examples, but it should be understood that this embodiment is intended to be illustrative only and not to be construed as limiting the invention. <Examples> 实施 Examples 1 to 6 were prepared according to the components of Table 1 below, and then separately subjected to vacuum melting and washing to obtain a steel embryo, followed by reheating according to the following table (degrees) SRT) 'The steel is heated in a high temperature furnace to obtain a heated steel embryo, respectively. The heated steel preform is subjected to a hot rolling step in a rolling mill, and then the heated steel slab is rolled to 4.5 mm according to the finish rolling temperature (FT) of the watch to obtain a finished steel. . Then, the rolled steel material was subjected to a cooling step in accordance with the coiling temperature (ct) of Table 1, and finally the hot milk steel materials of Examples 1 to 6 were obtained. [Comparative Examples 1 to 3] In the same manner as in the production processes of the following Table 1 and the above Examples 1 to 6, the hot-rolled steel materials of Comparative Examples 1 to 3 were finally obtained. ❹ 13 200944598 Table 1 No. Example Comparative Example 1 2 3 4 5 6 1 2 3 Composition C 0.08 0.08 0.12 0.08 0.12 0.08 0.12 0.10 0.12 Μη 1.53 1.55 1.52 1.53 1.51 1.50 1.51 1.50 1.50 Ti 0.14 0.15 0.14 0.18 0.18 0.12 0.18 0.09 0.04 V 0.04 0.04 0.04 0.04 0.04 a 0.04 - 0.03 Cr - 0.16 - 0.16 - 0.18 - 0.20 - Nb 0.03 - Si 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03 P 0.01 0.01 0.01 0.01 0,01 0.01 0.01 (KOI 0.01 S 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 N 0.004 0.004 0.004 0.004 0.004 0.004 0.004 0.004 0.004 0.004 Hot rolling parameters SRTb 1170 1170 1200 1220 1170 1170 1170 1100 1150 FTC 900 900 880 900 910 860 950 965 900 CTd 550 550 570 550 550 520 450 450 500 a Indicates not added b. SRT indicates reheating temperature (°C) c. FT indicates the rolling temperature (°C) d. CT indicates the coiling temperature (°C). [Test] The above examples and comparative examples Tested for the following properties: 1 · Yield strength (hereinafter referred to as "ys"): tested according to standard method CNS 2112, G2014 The unit is Mpa 〇2. Tensile strength (hereinafter referred to as "TS")· 14 200944598 Tested according to the standard method CNS 2112, G2014, the unit is MPa 〇 3. Elongation (hereinafter referred to as "E1%" ”: The test was carried out according to the standard method CNS 2112, G2014. The test results of the above Examples 1 to 6 and Comparative Examples 1 to 3 are as follows. Table 2 No. Example Comparative Example 1 2 3 4 5 6 1 2 3 YS 735 778 717 720 695 717 622 63Q 545 TS 777 807 758 795 745 747 685 656 632 EI 26 23 26 23 28 22 24 23 27
由表2結果可發現，實施例1〜6的降伏強度在 695〜778 MPa、抗拉強度為745〜807 MPa及伸長率為 22%〜28%。而相較於比較例1〜3，實施例1〜6的降伏強度 及抗拉強度皆高於比較例1〜3，伸長率則與比較例1〜3相 近。 此外，可發現比較例1雖添加較多量的碳和鈦，但 是盤捲溫度較低（450°C)，以致降伏強度及抗拉強度皆低 於700 MPa。比較例2雖另添加鈮，但因為再加熱溫度為 1100°C、完軋溫度高於950°C以及盤捲溫度較低，所以 仍無法提昇強度。在所有測試結果中，以比較例3的降伏 強度及抗拉強度為最差，這是因為鈦的含量較低，使得肥 粒鐵相的晶粒粗化以及析出物的量不足，導致強度最差。 15 200944598 由以上比較可證明，運用本發明的製備方法，適當 調整鋼胚中的成份組成以及含量比例，並控制再加熱溫 度（>1150。〇、完軋溫度（<95〇〇c)及盤捲溫度（48〇〜68〇〇c) ’確實可製得降伏強度及抗拉強度較高的熱軋鋼材。 再利用一電子顯微鏡，分別裁取實施例1〜6所製得 之熱軋鋼材進行顯微結構的觀察，可發現鋼材主要是以肥 粒鐵相為主，其粒徑約為2〜5 μιη，且肥粒鐵相中可發現 分散有大量的析出物，包含粒徑為20 nm以下的碳化鈦 ❹ 以及0.5〜5 μιη的氮化鈦析出物。 一综上所述，本發明高強度熱軋鋼材之製備方法透過適 當調整該鋼胚中之成份組成及含量比例，並控制再加熱溫 度（1150〇C以上）、完軋溫度（Ar3溫度以上）及盤捲溫度 (480〜68(PC)，使得所製得之熱軋鋼材以粒徑為2〜5 的肥 粒鐵相為主相，且在肥粒鐵相中分散有2〇 nm以下的碳化 鈦及0.5〜5 μιη的氮化鈦，而讓製得的熱軋鋼材具備高於 650 MPa的降伏強度、高於7〇〇 MPa的抗拉強度及22〜28% β 的伸長率，因此，本發明之高強度熱軋鋼材可符合後續應 用之需求，而本發明之製備方法可有效提昇鋼材的強度以 及維持加工性。 惟以上所述者’僅為本發明之較佳實施例而已，當不 月&以此限定本發明實施之範圍’即大凡依本發明申請專利 範圍及發明說明内容所作之簡單的等效變化與修飾，皆仍 屬本發明專利涵蓋之範圍内。 16 200944598From the results of Table 2, it was found that the tensile strengths of Examples 1 to 6 were 695 to 778 MPa, the tensile strength was 745 to 807 MPa, and the elongation was 22% to 28%. The tensile strength and tensile strength of Examples 1 to 6 were higher than those of Comparative Examples 1 to 3 as compared with Comparative Examples 1 to 3, and the elongation was similar to Comparative Examples 1 to 3. Further, it was found that Comparative Example 1 added a large amount of carbon and titanium, but the coiling temperature was low (450 ° C), so that the lodging strength and the tensile strength were both lower than 700 MPa. In Comparative Example 2, although yttrium was additionally added, the strength was not improved because the reheating temperature was 1,100 ° C, the finishing temperature was higher than 950 ° C, and the coiling temperature was low. Among all the test results, the drop strength and tensile strength of Comparative Example 3 were the worst, because the titanium content was low, and the grain coarsening of the ferrite grain iron phase and the amount of precipitates were insufficient, resulting in the highest strength. difference. 15 200944598 From the above comparison, it can be proved that the composition and content ratio in the steel embryo are appropriately adjusted by using the preparation method of the present invention, and the reheating temperature is controlled (> 1150. 〇, finishing temperature (<95〇〇c) And coil temperature (48〇~68〇〇c) 'It is possible to produce hot-rolled steel with high strength and tensile strength. Then use an electron microscope to cut the heat obtained in Examples 1 to 6 respectively. When the microstructure of the rolled steel is observed, it can be found that the steel is mainly composed of the iron phase of the ferrite, and its particle size is about 2~5 μιη, and a large amount of precipitates are scattered in the iron phase of the ferrite, including the particle size. It is a titanium carbide crucible of 20 nm or less and a titanium nitride precipitate of 0.5 to 5 μm. In summary, the preparation method of the high-strength hot-rolled steel of the present invention can appropriately adjust the composition and content ratio of the steel embryo. And control the reheating temperature (above 1150 〇C), the finishing temperature (above Ar3 temperature) and the coiling temperature (480~68 (PC), so that the prepared hot-rolled steel has a particle size of 2~5. The iron phase is the main phase, and 2〇 n is dispersed in the ferrite phase. Titanium carbide below 0.5 m and titanium nitride of 0.5 to 5 μηη, so that the obtained hot-rolled steel material has a drop strength higher than 650 MPa, a tensile strength higher than 7 MPa, and an elongation of 22 to 28% β Therefore, the high-strength hot-rolled steel of the present invention can meet the requirements of subsequent applications, and the preparation method of the present invention can effectively improve the strength of the steel and maintain the processability. However, the above is merely a preferred embodiment of the present invention. In addition, the simple equivalent changes and modifications made by the present invention in the scope of the invention and the scope of the invention are still within the scope of the invention. 16 200944598
【圖式簡單說明】 無 【主要元件符號說明】 無 17[Simple description of the diagram] None [Key component symbol description] None 17