TWI530571B - Fat iron type stainless steel and its manufacturing method - Google Patents
Fat iron type stainless steel and its manufacturing method Download PDFInfo
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- TWI530571B TWI530571B TW104100510A TW104100510A TWI530571B TW I530571 B TWI530571 B TW I530571B TW 104100510 A TW104100510 A TW 104100510A TW 104100510 A TW104100510 A TW 104100510A TW I530571 B TWI530571 B TW I530571B
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Description
本發明係關於成形性優異的肥粒鐵系不鏽鋼及其製造方法。 The present invention relates to a ferrite-based iron-based stainless steel excellent in formability and a method for producing the same.
肥粒鐵系不鏽鋼之中,由日本工業規格JIS G 4305所規定的SUS430(16~18質量%Cr),因為廉價且耐蝕性優異,因而被使用於建材、輸送機器、家電製品、廚房器具、汽車零件等各種用途,且近年來其適用範圍亦進而擴大中。為能適用於該等用途,不僅要求耐蝕性,尚且需求能加工為既定形狀的充分成形性(拉伸性大(以下將拉伸性大之事稱為「具有延性」)、平均蘭弗得值((Lankford value))(以下稱「平均r值」)大、及r值的平面內異向性絕對值(以下稱|Δr|)小)。 Among the ferrite-based stainless steels, SUS430 (16 to 18 mass% Cr), which is defined by Japanese Industrial Standard JIS G 4305, is used in building materials, transportation equipment, home electric appliances, kitchen appliances, and the like because it is inexpensive and excellent in corrosion resistance. Various uses such as automobile parts, and the scope of application in recent years has been further expanded. In order to be suitable for such applications, it is required to have not only corrosion resistance but also sufficient formability to be processed into a predetermined shape (large stretchability (hereinafter referred to as "ductile property"), and average Langford The value ((Lankford value)) (hereinafter referred to as "average r value") is large, and the absolute value of the in-plane anisotropy of the r value (hereinafter referred to as "Δr|) is small).
針對上述,專利文獻1所揭示的肥粒鐵系不鏽鋼,係成形性與抗皺性能均優異,依質量%計,含有:C:0.02~0.06%、Si:1.0%以下、Mn:1.0%以下、P:0.05%以下、S:0.01%以下、Al:0.005%以下、Ti:0.005%以下、Cr:11~30%、Ni:0.7%以下,且滿足0.06≦(C+N)≦0.12、1≦N/C及1.5×10-3≦(V×N)≦1.5×10-2(C、N、V分別係表示各元素的質量%)。但是,專利文獻1中關於異向性則完全沒有提及。又,經熱軋後必需施行所謂箱式退火(例如依860℃施行8小時退火)。因為此種箱式退火製程係包括有加熱、冷卻過程需要花費一週左右的時間,會有生產性低的問題。 In view of the above, the ferrite-based iron-based stainless steel disclosed in Patent Document 1 is excellent in moldability and wrinkle resistance, and contains, in terms of % by mass, C: 0.02 to 0.06%, Si: 1.0% or less, and Mn: 1.0% or less. P: 0.05% or less, S: 0.01% or less, Al: 0.005% or less, Ti: 0.005% or less, Cr: 11 to 30%, Ni: 0.7% or less, and satisfying 0.06 ≦ (C + N) ≦ 0.12, 1 ≦N/C and 1.5×10 -3 ≦(V×N)≦1.5×10 -2 (C, N, and V represent the mass % of each element, respectively). However, the anisotropy in Patent Document 1 is not mentioned at all. Further, after hot rolling, it is necessary to perform so-called box annealing (for example, annealing at 860 ° C for 8 hours). Since such a box annealing process involves heating and cooling processes, it takes about one week, and there is a problem of low productivity.
另一方面,專利文獻2所揭示的肥粒鐵系不鏽鋼,係加工性與表面性狀均優異肥粒鐵系不鏽鋼,特徵在於將依質量%計,含有:C:0.01~0.10%、Si:0.05~0.50%、Mn:0.05~1.00%、Ni:0.01~0.50%、Cr:10~20%、Mo:0.005~0.50%、Cu:0.01~0.50%、V:0.001~0.50%、Ti:0.001~0.50%、Al:0.01~0.20%、Nb:0.001~0.50%、N:0.005~0.050%及B:0.00010~0.00500%的鋼施行熱軋後,再使用箱式爐(box furnace)或AP處理線(annealing and pickling line,退火酸洗處理線)連續爐,依肥粒鐵單相溫度區域施行熱軋板退火,更施行冷軋及精製退火。但是,使用箱式爐時將與上述專利文獻1同樣地會有生產性低的問題。又,專利文獻2中關於拉伸性完全沒有提及,當利用連續退火爐依肥粒鐵單相溫度區域施行熱軋板退火的情況,因為退火溫度低因而再結晶不充分,相較於依肥粒鐵單相溫度區域施行箱式退火的情況下,拉伸性較為降低。又,一般如專利文獻2所示肥粒鐵系不鏽鋼,會生成具有類似鑄造或熱軋時之結晶方位的結晶粒群(群體、colony),導致有|Δr|變大的問題。 On the other hand, the ferrite-based iron-based stainless steel disclosed in Patent Document 2 is excellent in both workability and surface properties, and is characterized in that it contains, by mass%, C: 0.01 to 0.10%, Si: 0.05. ~0.50%, Mn: 0.05~1.00%, Ni: 0.01~0.50%, Cr: 10~20%, Mo: 0.005~0.50%, Cu: 0.01~0.50%, V: 0.001~0.50%, Ti: 0.001~ 0.50%, Al: 0.01~0.20%, Nb: 0.001~0.50%, N: 0.005~0.050%, and B: 0.00010~0.00500% steel are hot rolled, and then box furnace or AP processing line is used. (annealing and pickling line, annealing and pickling line) continuous furnace, according to the ferrite iron single-phase temperature region to perform hot-rolled sheet annealing, more cold rolling and refined annealing. However, when a box type furnace is used, the productivity is low as in the case of Patent Document 1 described above. Further, Patent Document 2 does not mention at all about the stretchability. When the hot-rolled sheet is annealed in a single-phase temperature region of a continuous annealing furnace, the recrystallization is insufficient because the annealing temperature is low. In the case of box annealing in the single-phase temperature region of the ferrite-grained iron, the stretchability is lowered. Further, in general, the ferrite-based iron-based stainless steel shown in Patent Document 2 generates a crystal grain group (group, colony) having a crystal orientation similar to that at the time of casting or hot rolling, resulting in a problem that |Δr| becomes large.
專利文獻1:日本專利第3584881號公報(再公表WO00/60134號) Patent Document 1: Japanese Patent No. 3,584,881 (Reissue No. WO00/60134)
專利文獻2:日本專利第3581801號公報(特開2001-3134號) Patent Document 2: Japanese Patent No. 3581801 (JP-2001-3134)
本發明係解決此項問題,目的在於提供:具有充分耐蝕性及優異成形性的肥粒鐵系不鏽鋼及其製造方法。 The present invention has been made in view of the above problems, and an object thereof is to provide a ferrite-based iron-based stainless steel having sufficient corrosion resistance and excellent formability and a method for producing the same.
另外,本發明中,所謂「充分耐蝕性」係指對表面經利用#600剛砂紙施行拋光加工後再將端面部予以密封的鋼板,施行JIS H 8502所規定的鹽水噴霧循環試驗[以(鹽水噴霧(35℃、5質量%NaCl、噴霧2h)→乾燥(60℃、相對濕度40%、4h)→濕潤(50℃、相對濕度≧95%、2h))為1循環的試驗]計施行8循環時,鋼板表面的生銹面積率(=生銹面積/鋼板總面積×100[%])在25%以下。 In the present invention, the term "sufficient corrosion resistance" refers to a steel plate which is subjected to a polishing process using a #600 rigid sandpaper and then seals the end surface portion, and performs a salt spray cycle test as specified in JIS H 8502. Spray (35 ° C, 5 mass % NaCl, spray 2 h) → dry (60 ° C, relative humidity 40%, 4 h) → wet (50 ° C, relative humidity ≧ 95%, 2 h)) 1 cycle test] At the time of circulation, the rust area ratio (=rust area/total steel plate area × 100 [%]) on the surface of the steel sheet was 25% or less.
再者,所謂「優異成形性」係指在根據JIS Z2241的拉伸試驗中,斷裂拉伸(El)達25%以上之情況,根據JIS Z 2241的拉伸試驗中,賦予15%應變時利用下述(1)式所計算出的平均蘭弗得值(以下稱「平均r值」)達0.70以上之情況,以及依下述(2)式所計算出r值的平面內異向性(以下稱「Δr」)絕對值(|Δr|)在0.20以下之情況。 In the tensile test according to JIS Z 2241, the tensile elongation at break (El) is 25% or more, and in the tensile test according to JIS Z 2241, the strain is applied at 15% strain. The average Ranke value (hereinafter referred to as "average r value") calculated by the following formula (1) is 0.70 or more, and the in-plane anisotropy of the r value calculated by the following formula (2) ( Hereinafter, the "Δr") absolute value (|Δr|) is 0.20 or less.
平均r值=(rL+2×rD+rC)/4 (1) Average r value = (r L + 2 × r D + r C ) / 4 (1)
Δr=(rL-2×rD+rC)/2 (2) Δr=(r L -2×r D +r C )/2 (2)
其中,rL係朝軋延方向的平行方向施行拉伸試驗時的r值;rD係朝軋延方向的45°方向施行拉伸試驗時的r值;rC係朝軋延方向的直角方向施行拉伸試驗時的r值。 Wherein a direction parallel to the direction of the line L and rolling toward the purposes of the r value r tensile test; r D r value based implementation of the tensile test at 45 ° toward the direction and rolling direction; r C toward the line and rolling direction at right angles The r value at the time of the tensile test.
為解決問題經深入鑽研,結果發現藉由在針對適當成分肥粒鐵系不鏽鋼進行熱軋後的鋼板,於施行冷軋前,便依成為肥粒鐵相與沃斯田鐵相之雙相的溫度區域施行退火,便可獲得具有充分耐蝕性、且成形性優異的肥粒鐵系不鏽鋼。 After intensive research to solve the problem, it was found that the steel sheet after hot rolling of the ferrite-based stainless steel for the appropriate composition was used as the two-phase of the ferrite phase and the Worthite iron phase before the cold rolling. When the temperature region is annealed, a ferrite-based iron-based stainless steel having sufficient corrosion resistance and excellent formability can be obtained.
本發明係根據以上見解而完成,主旨如下。 The present invention has been completed based on the above findings, and the gist thereof is as follows.
[1]一種肥粒鐵系不鏽鋼,係依質量%計,含有:C:0.005~0.05%、Si:0.02~0.50%、Mn:0.05~1.0%、P:0.04%以下、S:0.01%以下、 Cr:15.5~18.0%、Al:0.001~0.10%、N:0.01~0.06%,其餘係Fe及不可避免的雜質構成,El≧25%、平均r值≧0.70且|Δr|≦0.20。 [1] A ferrite-based iron-based stainless steel containing C: 0.005 to 0.05%, Si: 0.02 to 0.50%, Mn: 0.05 to 1.0%, P: 0.04% or less, and S: 0.01% or less, in terms of mass%. , Cr: 15.5 to 18.0%, Al: 0.001 to 0.10%, N: 0.01 to 0.06%, and the rest are composed of Fe and unavoidable impurities, and El ≧ 25%, average r value ≧ 0.70, and | Δr | ≦ 0.20.
[2]一種肥粒鐵系不鏽鋼,係依質量%計,含有:C:0.01~0.05%、Si:0.02~0.50%、Mn:0.2~1.0%、P:0.04%以下、S:0.01%以下、Cr:16.0~18.0%、Al:0.001~0.10%、N:0.01~0.06%,其餘係Fe及不可避免的雜質構成,El≧25%、平均r值≧0.70且|Δr|≦0.20。 [2] A ferrite-based iron-based stainless steel containing, by mass%, C: 0.01 to 0.05%, Si: 0.02 to 0.50%, Mn: 0.2 to 1.0%, P: 0.04% or less, and S: 0.01% or less Cr: 16.0~18.0%, Al: 0.001~0.10%, N: 0.01~0.06%, and the rest are composed of Fe and unavoidable impurities, El≧25%, average r value ≧0.70 and |Δr|≦0.20.
[3]如上述[1]或[2]所記載的肥粒鐵系不鏽鋼,其中,依質量%計,更進一步含有從Cu:0.1~1.0%、Ni:0.1~1.0%、Mo:0.1~0.5%、Co:0.01~0.5%之中選擇1種或2種以上。 [3] The ferrite-based stainless steel according to the above [1] or [2], which further contains, in terms of % by mass, from 0.1 to 1.0% of Cu, from 0.1 to 1.0% of Ni, and from 0.1 to 1.0% of Mo. One or two or more of 0.5% and Co: 0.01 to 0.5% are selected.
[4]如上述[1]~[3]中任一項所記載的肥粒鐵系不鏽鋼,其中,依質量%計,更進一步含有從V:0.01~0.25%、Ti:0.001~0.10%、Nb:0.001~0.10%、Mg:0.0002~0.0050%、B:0.0002~0.0050%、REM:0.01~0.10%、Ca:0.0002~0.0020%之中選擇1種或2種以上。 [4] The ferrite-based iron-based stainless steel according to any one of [1] to [3], further comprising, in terms of % by mass, from V: 0.01 to 0.25%, Ti: 0.001 to 0.10%, Nb: 0.001 to 0.10%, Mg: 0.0002 to 0.0050%, B: 0.0002 to 0.0050%, REM: 0.01 to 0.10%, and Ca: 0.0002 to 0.0020%, one or two or more selected.
[5]一種肥粒鐵系不鏽鋼之製造方法,係將具有上述[1]至[4]中任一項所記載成分組成的鋼胚,施行熱軋,接著施行依900~1000℃溫度範圍保持5秒~15分鐘的退火而形成熱軋退火板,接著經施行冷軋後,再施行依800~950℃溫度範圍保持5秒~5分鐘的冷軋板退火。 [5] A method for producing a ferrite-based iron-based stainless steel, which comprises subjecting a steel preform having the composition described in any one of the above [1] to [4] to hot rolling, and then performing the temperature range of 900 to 1000 ° C. Annealing is performed for 5 seconds to 15 minutes to form a hot rolled annealed sheet, followed by cold rolling, followed by annealing of a cold rolled sheet maintained at a temperature of 800 to 950 ° C for 5 seconds to 5 minutes.
另外,本說明書中,表示鋼成分的「%」全部均指「質量%」。 In addition, in this specification, "%" of a steel component all mean "mass %."
根據本發明可獲得具有充分耐蝕性與優異成形性的肥粒鐵系不鏽鋼。 According to the present invention, a ferrite-based iron-based stainless steel having sufficient corrosion resistance and excellent formability can be obtained.
以下,針對本發明進行詳細說明。 Hereinafter, the present invention will be described in detail.
本發明之肥粒鐵系不鏽鋼之目的在於:經衝壓加工能使用於建材零件、家電製品的零件、廚房器具、汽車零件等各種用途。為能適用於該等用途,要求充分成形性(拉伸性及平均r值大、|Δr|小)。 The purpose of the ferrite-grained stainless steel of the present invention is that it can be used for various purposes such as building materials parts, home appliance parts, kitchen appliances, and automobile parts by press working. In order to be suitable for such applications, sufficient formability (stretchability and average r value is large, |Δr| is small) is required.
例如當依撐壓成形製造球形排氣口罩的情況,若拉伸性特性不足,則在成形時會在拉伸性最差的方向上發生頸縮、斷裂情形,導致無法成形。又,經成形後的撐壓部位之板厚,會依成形前的鋼板方向出現大幅不同,導致發生製品外觀惡化的情況。或利用深衝加工等製造的大型鍋,當平均r值偏低的情況會發生頸縮、斷裂,導致無法成形為既定的製品形狀。鍋的鍋身部分之板厚會依位置出現大幅差異,導致熱傳導特性上發生不良情況。或當利用深衝加工進行成形時,若|Δr|偏大,則經成形後的邊緣會變大,導致因成形後的追加修邊步驟而造成製造成本增加,以及因被切掉的鋼板量變大而造成製品良率降低。依此期待拉伸性及平均r值大、且|Δr|小。但是,通常若平均r值變大,會導致|Δr|亦變大。所以,發明者等針對使用於建材、輸送機器、家電製品、廚房機器、汽車零件等各種用途的衝壓成形加工品進行深入調查,發現若同時滿足El≧25%、平均r值≧0.70、以及|Δr|≦0.20,便可衝壓成形為多樣加工品。 For example, when a spherical exhaust mask is produced by press-molding, if the stretchability is insufficient, necking or fracture may occur in the direction of the worst stretchability during molding, resulting in failure to form. Further, the thickness of the pressed portion after the forming is greatly different depending on the direction of the steel sheet before forming, and the appearance of the product is deteriorated. Or a large-scale pot manufactured by deep-drawing processing or the like may cause necking and fracture when the average r value is low, and it may not be formed into a predetermined product shape. The thickness of the pan portion of the pan will vary greatly depending on the position, resulting in a poor thermal conductivity. Or when forming by deep drawing, if |Δr| is too large, the edge after molding becomes large, the manufacturing cost increases due to the additional trimming step after forming, and the amount of the steel sheet to be cut is changed. Large, resulting in lower product yield. Accordingly, the stretchability and the average r value are expected to be large, and |Δr| is small. However, generally, if the average r value becomes large, |Δr| also becomes large. Therefore, the inventors conducted in-depth investigations on press-formed products used for various purposes such as building materials, conveyors, home appliances, kitchen appliances, and automobile parts, and found that if both ≧25%, average r value ≧0.70, and | Δr|≦0.20 can be press-formed into a variety of processed products.
肥粒鐵系不鏽鋼之中,依日本工業規格JIS G 4305規定的SUS430LX(16質量%Cr-0.15質量%Ti或16質量%Cr-0.4質量%Nb)、SUS436L(18質量%Cr-1.0質量%Mo-0.25質量%Ti)等,係含有大量的Ti、Nb,且具有拉伸性(El)及平均r值均優異的成形性,被使用於多種用途。但是,該等鋼種因為含有大量的Ti、Nb,因而會有原料成本與製造成本偏高、價格貴的問題。另一方面,肥粒鐵系不鏽鋼中生產最 多的SUS430(16質量%),因為並未含有大量的Ti、Nb,因而雖較SUS430LX、SUS436L廉價,但成形性卻較差於SUS430LX、SUS436L。所以,需求經提升成形性的SUS430。 Among the ferrite-based stainless steels, SUS430LX (16 mass% Cr-0.15 mass% Ti or 16 mass% Cr-0.4 mass% Nb) and SUS436L (18 mass% Cr-1.0 mass%) according to Japanese Industrial Standard JIS G 4305 Mo-0.25 mass% Ti) or the like contains a large amount of Ti and Nb, and has excellent moldability of both stretchability (El) and average r value, and is used in various applications. However, since these steel types contain a large amount of Ti and Nb, there is a problem that the raw material cost and the manufacturing cost are high and the price is expensive. On the other hand, the production of fat iron-based stainless steel is the most Since SUS430 (16 mass%) is not contained in a large amount of Ti and Nb, it is cheaper than SUS430LX and SUS436L, but its formability is inferior to SUS430LX and SUS436L. Therefore, the demand has been improved by the formability of SUS430.
緣是,發明者等針對獲得未含有大量Ti、Nb的SUS430(16質量%)系成分,且滿足El≧25%、平均r值≧0.70、|Δr|≦0.20的肥粒鐵系不鏽鋼之方法進行深入鑽研。又,就對經熱軋後的肥粒鐵系不鏽鋼板施行冷軋前,便施行退火(以下稱「熱軋板退火」)的方法,係有箱式退火(批次退火)與連續退火,針對不採用需要長時間且生產性低的箱式退火,而是利用高生產性連續退火獲得既定成形性進行檢討。 In the method of obtaining a SUS430 (16 mass%)-based component which does not contain a large amount of Ti and Nb, and the method of the inventors, etc., which satisfies the ferrite-based stainless steel of El≧25%, average r value ≧0.70, |Δr|≦0.20, Conduct in-depth research. Moreover, the method of annealing (hereinafter referred to as "hot-rolled sheet annealing") is performed on the hot-rolled iron-based stainless steel sheet after hot rolling, and is subjected to box annealing (batch annealing) and continuous annealing. In view of not using a box type annealing which requires a long time and low productivity, a high productivity continuous annealing is used to obtain a predetermined formability for review.
使用連續退火爐的習知技術之問題在於:因為熱軋板退火係依肥粒鐵單相溫度區域實施,因而不會產生充分的再結晶,無法獲得充分的拉伸性,且群體會殘存至冷軋板退火後,因而|Δr|偏大。緣是,發明者等提案出在依肥粒鐵相與沃斯田鐵相的雙相區域施行熱軋板退火後,依常法施行冷軋及冷軋板退火,最終再度成為肥粒鐵單相組織。即,藉由熱軋板退火係依較肥粒鐵單相溫度區域更高溫的肥粒鐵相與沃斯田鐵之雙相區域實施,便促進肥粒鐵相的再結晶,因而可迴避因熱軋而被導入加工應變的肥粒鐵結晶粒殘存直到冷軋板退火後為止,俾提升冷軋板退火後的拉伸性。又,當利用熱軋板退火從肥粒鐵相生成沃斯田鐵相時,因為沃斯田鐵相會生成具有與退火前的肥粒鐵相不同結晶方位,因而能有效地破壞肥粒鐵相的群體。所以,經施行冷軋與冷軋板退火後的冷軋退火板金屬組織中,會提升r值的γ-纖維集合組織繁盛,且群體會被切斷,緩和金屬組織的異向性,能獲得|Δr|變小的優異特性。 A problem with the conventional technique of using a continuous annealing furnace is that since the hot-rolled sheet annealing is carried out in accordance with the single-phase temperature region of the ferrite iron, sufficient recrystallization does not occur, sufficient stretchability cannot be obtained, and the population remains until After the cold rolled sheet is annealed, |Δr| is excessively large. The reason is that the inventor proposed to perform hot-rolled sheet annealing in the two-phase region of the ferrite phase and the Worthfield iron phase, and then perform cold rolling and cold-rolled sheet annealing according to the usual method, and finally become the ferrite iron sheet again. Organization. That is, the annealing of the hot-rolled sheet is carried out according to the two-phase region of the ferrite-rich iron phase which is higher in the single-phase temperature region of the ferrite-rich iron, and promotes the recrystallization of the iron phase of the ferrite, thereby avoiding the cause The ferrite-grained iron crystal grains which are introduced into the processing strain by hot rolling remain until the cold-rolled sheet is annealed, and the stretchability after annealing of the cold-rolled sheet is improved. Moreover, when the Wolster iron phase is formed from the ferrite grain iron phase by the hot-rolled sheet annealing, since the Worthfield iron phase is formed to have a crystal orientation different from that of the ferrite grain before annealing, the ferrite iron can be effectively destroyed. The group of the phase. Therefore, in the cold-rolled annealed sheet metal structure after cold rolling and cold-rolled sheet annealing, the γ-fiber aggregate structure which raises the r value is prosperous, and the group is cut off, and the anisotropy of the metal structure is alleviated, and the obtained |Δr| is excellent in characteristics.
再者,若對含有麻田散鐵相的熱軋退火板施行冷軋,因為麻田散鐵相相較於肥粒鐵相屬於較硬質,因而麻田散鐵相附近的肥粒鐵相會優先變形而導致軋延應變集中,而更增加冷軋板退火時的再結晶位置。藉此,更促進冷軋板退火時的再結晶,更加緩和冷軋板退火後的金屬組織異向性。 Furthermore, if the hot-rolled annealed sheet containing the granulated iron phase is cold-rolled, since the granulated iron phase is relatively harder than the ferrite-iron phase, the ferrite-phase iron phase near the granulated iron phase preferentially deforms. This leads to the concentration of the rolling strain and increases the recrystallization position when the cold rolled sheet is annealed. Thereby, recrystallization at the time of annealing of the cold-rolled sheet is further promoted, and metal anisotropy after annealing of the cold-rolled sheet is further alleviated.
再者,針對各種成分,就雙相區域熱軋板退火的效果進行詳細檢討,結果發現即便未含有大量的Ti、Nb,但利用適當的成分,仍可獲得拉伸性(El)達25%以上、平均r值達0.70以上、|Δr|在0.20以下的優異成形性。 Furthermore, in detail, the effect of annealing the hot-rolled sheet in the two-phase region was examined in detail for each component, and it was found that even if a large amount of Ti and Nb were not contained, the stretchability (El) was 25% by using an appropriate component. The above, the average r value is 0.70 or more, and the excellent formability of |Δr| is 0.20 or less.
其次,針對本發明肥粒鐵系不鏽鋼的成分組成進行說明。以下,在無特別聲明的前提下,「%」係指「質量%」。 Next, the composition of the ferrite-based iron-based stainless steel of the present invention will be described. Hereinafter, "%" means "% by mass" unless otherwise stated.
C:0.005~0.05% C: 0.005~0.05%
C係具有促進沃斯田鐵相生成,擴大熱軋板退火時會出現肥粒鐵相與沃斯田鐵相的雙相溫度區域之效果。為能獲得此項效果必需含有達0.005%以上。但是,若C量超過0.05%,則鋼板會硬質化導致延性降低。所以,C量設定為0.005~0.05%範圍。下限較佳係0.01%、更佳係0.015%。上限較佳係0.035%、更佳係0.03%、特佳係0.025%。 The C system has the effect of promoting the formation of the iron phase of the Worthfield and expanding the two-phase temperature region of the ferrite phase and the Worthite iron phase during annealing of the hot rolled sheet. In order to obtain this effect, it must be more than 0.005%. However, when the amount of C exceeds 0.05%, the steel sheet is hardened to cause a decrease in ductility. Therefore, the amount of C is set to be in the range of 0.005 to 0.05%. The lower limit is preferably 0.01%, more preferably 0.015%. The upper limit is preferably 0.035%, more preferably 0.03%, and particularly preferably 0.025%.
Si:0.02~0.50% Si: 0.02~0.50%
Si係屬於在鋼熔製時發揮脫氧劑的作用。為能獲得此項效果必需含有達0.02%以上。但是,若Si量超過0.50%,則鋼板會硬質化導致熱軋時的軋延負荷增大。又,冷軋板退火後的延性會降低。所以,Si量設定為0.02~0.50%範圍。較佳係0.10~0.50%範圍。更佳係0.25~0.35% 範圍。 The Si system functions as a deoxidizer when the steel is melted. In order to obtain this effect, it must be more than 0.02%. However, when the amount of Si exceeds 0.50%, the steel sheet is hardened and the rolling load during hot rolling is increased. Moreover, the ductility after annealing of the cold rolled sheet is lowered. Therefore, the amount of Si is set to be in the range of 0.02 to 0.50%. It is preferably in the range of 0.10 to 0.50%. Better 0.25~0.35% range.
Mn:0.05~1.0% Mn: 0.05~1.0%
Mn係與C同樣地均具有促進沃斯田鐵相生成,擴大熱軋板退火時會出現肥粒鐵相與沃斯田鐵相的雙相溫度區域之效果。為能獲得此項效果必需含有達0.05%以上。但是,若Mn量超過1.0%,則MnS的生成量會增加導致耐蝕性降低。所以,Mn量設定為0.05~1.0%範圍。下限較佳係0.1%、更佳係0.2%。上限較佳係0.8%、更佳係0.35%、特佳係0.3%。 Similarly to C, the Mn system promotes the formation of the iron phase of the Worthfield, and expands the effect of the two-phase temperature region of the ferrite phase and the Worthite iron phase during the annealing of the hot rolled sheet. In order to obtain this effect, it must be more than 0.05%. However, when the amount of Mn exceeds 1.0%, the amount of MnS produced increases, and the corrosion resistance decreases. Therefore, the amount of Mn is set to be in the range of 0.05 to 1.0%. The lower limit is preferably 0.1%, more preferably 0.2%. The upper limit is preferably 0.8%, more preferably 0.35%, and particularly preferably 0.3%.
P:0.04%以下 P: 0.04% or less
P係屬於會助長因晶界偏析而造成晶界破壞的元素,所以越少越好,上限設定為0.04%。較佳係0.03%以下。更佳係0.01%以下。 The P system is an element that contributes to the destruction of the grain boundary due to segregation at the grain boundary, so the smaller the better, the upper limit is set to 0.04%. Preferably, it is 0.03% or less. More preferably, it is 0.01% or less.
S:0.01%以下 S: 0.01% or less
S係屬於會存在成為MnS等硫化物系介在物導致延性與耐蝕性等降低的元素。特別係當含有量超過0.01%的情況,該等不良影響會明顯發生。所以,S量最好盡量減少,本發明中的S量上限係設定為0.01%。更佳係0.007%以下。特佳係0.005%以下。 The S system is an element that causes a decrease in ductility, corrosion resistance, and the like due to a sulfide system such as MnS. In particular, when the content exceeds 0.01%, such adverse effects may occur remarkably. Therefore, the amount of S is preferably as small as possible, and the upper limit of the amount of S in the present invention is set to 0.01%. More preferably, it is 0.007% or less. Very good is 0.005% or less.
Cr:15.5~18.0% Cr: 15.5~18.0%
Cr係屬於具有在鋼板表面上形成鈍化皮膜而提升耐蝕性效果的元素。為能獲得此項效果必需將Cr量設定為15.5%以上。但是,若Cr量超過18.0%,則在熱軋板退火時的沃斯田鐵相生成嫌不足,導致無 法獲得既定的材料特性。所以,Cr量設定為15.5~18.0%範圍。較佳係16.0~18.0%範圍。更佳係16.0~17.25%範圍。 The Cr system is an element having a passivation film formed on the surface of the steel sheet to enhance the corrosion resistance effect. In order to obtain this effect, the amount of Cr must be set to 15.5% or more. However, if the amount of Cr exceeds 18.0%, the formation of the Worthite iron phase during the annealing of the hot rolled sheet is insufficient, resulting in no The method obtains the established material properties. Therefore, the amount of Cr is set to be in the range of 15.5 to 18.0%. Preferably, it is in the range of 16.0 to 18.0%. More preferably in the range of 16.0 to 17.25%.
Al:0.001~0.10% Al: 0.001~0.10%
Al係與Si同樣地屬於具有脫氧劑作用的元素。為能獲得此項效果必需含有達0.001%以上。但是,若Al量超過0.10%,則Al2O3等Al系夾雜物會增加,導致表面性狀容易降低。所以,Al量設定為0.001~0.10%範圍。較佳係0.001~0.05%範圍。更佳係0.001~0.03%範圍。 The Al system belongs to an element having a function as a deoxidizer similarly to Si. In order to obtain this effect, it must be more than 0.001%. However, when the amount of Al exceeds 0.10%, Al-based inclusions such as Al 2 O 3 increase, and surface properties are liable to lower. Therefore, the amount of Al is set to be in the range of 0.001 to 0.10%. It is preferably in the range of 0.001 to 0.05%. More preferably in the range of 0.001 to 0.03%.
N:0.01~0.06% N: 0.01~0.06%
N係與C、Mn同樣地具有促進沃斯田鐵相生成,擴大熱軋板退火時會出現肥粒鐵相與沃斯田鐵相的雙相溫度區域之效果。為能獲得此項效果必需將N量設定達0.01%以上。但是,若N量超過0.06%,則延性會明顯降低,且會因助長鉻之氮化物析出而導致耐蝕性降低。所以,N量設定為0.01~0.06%範圍。較佳係0.01~0.05%範圍。更佳係0.02~0.04%範圍。 Similarly to C and Mn, the N system has an effect of promoting the formation of the iron phase of the Worthfield, and expanding the two-phase temperature region of the ferrite phase and the Worthite iron phase when the hot rolled sheet is annealed. In order to obtain this effect, the amount of N must be set to 0.01% or more. However, if the amount of N exceeds 0.06%, the ductility is remarkably lowered, and the corrosion resistance is lowered by the precipitation of the nitride which promotes chromium. Therefore, the amount of N is set to be in the range of 0.01 to 0.06%. It is preferably in the range of 0.01 to 0.05%. More preferably in the range of 0.02 to 0.04%.
其餘係Fe及不可避免的雜質。 The rest are Fe and inevitable impurities.
藉由以上的成分組成便可獲得本發明的效果,更在提升製造性或材料特性之目的,尚可含有以下的元素。 The effects of the present invention can be obtained by the above composition, and the following elements can be contained for the purpose of improving manufacturability or material properties.
從Cu:0.1~1.0%、Ni:0.1~1.0%、Mo:0.1~0.5%、Co:0.01~0.5%之中選擇1種或2種以上 One or two or more selected from the group consisting of Cu: 0.1 to 1.0%, Ni: 0.1 to 1.0%, Mo: 0.1 to 0.5%, and Co: 0.01 to 0.5%.
Cu與Ni均係屬於提升耐蝕性的元素,特別係當要求高耐蝕性的 情況含有便屬有效。又,Cu與Ni均具有促進沃斯田鐵相生成,擴大熱軋板退火時會出現肥粒鐵相與沃斯田鐵相的雙相溫度區域之效果。該等效果分別係含有達0.1%以上才會明顯。但是,若Cu含有量超過1.0%,則熱加工性會降低,故非屬較佳。所以,當含有Cu的情況便設定為0.1~1.0%。較佳係0.2~0.8%範圍。更佳係0.3~0.5%範圍。若Ni含有量超過1.0%,則加工性會降低,故非屬較佳。所以,當含有Ni的情況便設定為0.1~1.0%。較佳係0.1~0.6%範圍。更佳係0.1~0.3%範圍。 Both Cu and Ni are elements that enhance corrosion resistance, especially when high corrosion resistance is required. The situation is valid. Further, both Cu and Ni have the effect of promoting the formation of the iron phase of the Worthfield, and expanding the two-phase temperature region of the ferrite phase and the Worthite iron phase when the hot rolled sheet is annealed. These effects are only apparent if they contain more than 0.1%. However, when the Cu content exceeds 1.0%, the hot workability is lowered, which is not preferable. Therefore, when Cu is contained, it is set to 0.1 to 1.0%. It is preferably in the range of 0.2 to 0.8%. More preferably in the range of 0.3 to 0.5%. When the Ni content exceeds 1.0%, the workability is lowered, which is not preferable. Therefore, when Ni is contained, it is set to 0.1 to 1.0%. It is preferably in the range of 0.1 to 0.6%. More preferably in the range of 0.1 to 0.3%.
Mo係屬於提升耐蝕性的元素,特別係當要求高耐蝕性的情況含有便屬有效。此項效果係含有達0.1%以上才會明顯。但是,若Mo含有量超過0.5%,則在熱軋板退火時的沃斯田鐵相生成嫌不足,無法獲得既定的材料特性,故非屬較佳。所以,當含有Mo的情況便設定為0.1~0.5%以下。較佳係0.1~0.3%範圍。 Mo is an element that enhances corrosion resistance, and is particularly effective when it is required to have high corrosion resistance. This effect is more than 0.1%. However, when the Mo content exceeds 0.5%, the formation of the Worthite iron phase during the annealing of the hot rolled sheet is insufficient, and the predetermined material properties cannot be obtained, which is not preferable. Therefore, when Mo is contained, it is set to 0.1 to 0.5% or less. It is preferably in the range of 0.1 to 0.3%.
Co係屬於提升韌性的元素。此項效果係藉由含有達0.01%以上便可獲得。另一方面,若含有量超過0.5%,便會使製造性降低。所以,當含有Co時,含有量設定為0.01~0.5%範圍。 Co is an element that enhances toughness. This effect can be obtained by containing more than 0.01%. On the other hand, if the content exceeds 0.5%, the manufacturability is lowered. Therefore, when Co is contained, the content is set to be in the range of 0.01 to 0.5%.
從V:0.01~0.25%、Ti:0.001~0.10%、Nb:0.001~0.10%、Mg:0.0002~0.0050%、B:0.0002~0.0050%、REM:0.01~0.10%、Ca:0.0002~0.0020%之中選擇1種或2種以上 From V: 0.01 to 0.25%, Ti: 0.001 to 0.10%, Nb: 0.001 to 0.10%, Mg: 0.0002 to 0.0050%, B: 0.0002 to 0.0050%, REM: 0.01 to 0.10%, Ca: 0.0002 to 0.0020% Choose one or more of them
V:0.01~0.25% V: 0.01~0.25%
V會與鋼中的C及N化合,而降低固溶C、N。藉此提升平均r值。又,控制熱軋板中的氮碳化物析出行為,抑制因熱軋/退火造成的線狀瑕疵產生,而改善表面性狀。為能獲得此項效果V量必需含有達 0.01%以上。但是,若V量超過0.25%,則加工性會降低,且會導致製造成本上升。所以,V量設定為0.01~0.25%範圍。較佳係0.03~0.20%範圍。更佳係0.05~0.15%範圍。 V will combine with C and N in steel to reduce solid solution C and N. Thereby increasing the average r value. Further, the precipitation behavior of the nitrogen carbides in the hot rolled sheet is controlled, and the occurrence of linear defects due to hot rolling/annealing is suppressed, and the surface properties are improved. In order to obtain this effect, the amount of V must be 0.01% or more. However, if the amount of V exceeds 0.25%, the workability is lowered and the manufacturing cost is increased. Therefore, the amount of V is set to be in the range of 0.01 to 0.25%. It is preferably in the range of 0.03 to 0.20%. More preferably in the range of 0.05 to 0.15%.
Ti:0.001~0.10%、Nb:0.001~0.10% Ti: 0.001 to 0.10%, Nb: 0.001 to 0.10%
Ti及Nb係與V同樣地屬於與C及N間之親和力較高的元素,在熱軋時會依碳化物或氮化物形式析出,使母相中的固溶C、N降低,具有提升經冷軋板退火後的加工性效果。為能獲得該等效果,必需含有達0.001%以上的Ti、達0.001%以上的Nb。但是,若Ti量超過0.10%、或Nb量超過0.10%,則會因析出過剩的TiN與NbC,導致無法獲得良好的表面性狀。所以,當含有Ti的情況便設定為0.001~0.10%範圍,當含有Nb的情況便設定為0.001~0.10%範圍。Ti量較佳係0.001~0.015%範圍。更佳係0.003~0.010%範圍。Nb量較佳係0.001~0.025%範圍。更佳係0.005~0.020%範圍。 Like the V, Ti and Nb are elements having a high affinity with C and N, and are precipitated in the form of carbides or nitrides during hot rolling to lower the solid solution C and N in the parent phase. The workability effect after annealing the cold rolled sheet. In order to obtain such effects, it is necessary to contain 0.001% or more of Ti and 0.001% or more of Nb. However, when the amount of Ti exceeds 0.10% or the amount of Nb exceeds 0.10%, excessive TiN and NbC are precipitated, and good surface properties cannot be obtained. Therefore, when Ti is contained, it is set to a range of 0.001 to 0.10%, and when Nb is contained, it is set to a range of 0.001 to 0.10%. The amount of Ti is preferably in the range of 0.001 to 0.015%. More preferably in the range of 0.003 to 0.010%. The amount of Nb is preferably in the range of 0.001 to 0.025%. More preferably in the range of 0.005 to 0.020%.
Mg:0.0002~0.0050% Mg: 0.0002~0.0050%
Mg係屬於具有提升熱加工性效果的元素。為能獲得此項效果必需含有達0.0002%以上。但是,若Mg量超過0.0050%,則表面品質會降低。所以,當含有Mg的情況便設定為0.0002~0.0050%範圍。較佳係0.0005~0.0035%範圍。更佳係0.0005~0.0020%範圍。 The Mg system is an element having an effect of improving hot workability. In order to obtain this effect, it must be more than 0.0002%. However, if the amount of Mg exceeds 0.0050%, the surface quality is lowered. Therefore, when Mg is contained, it is set in the range of 0.0002 to 0.0050%. Preferably, it is in the range of 0.0005 to 0.0035%. More preferably in the range of 0.0005 to 0.0020%.
B:0.0002~0.0050% B: 0.0002~0.0050%
B係屬於防止低溫二次加工脆化的有效元素。為能獲得此項效果必需含有達0.0002%以上。但是,若B量超過0.0050%,則熱加工性會 降低。所以,當含有B的情況便設定為0.0002~0.0050%範圍。較佳係0.0005~0.0035%範圍。更佳係0.0005~0.0020%範圍。 B is an effective element to prevent embrittlement in low temperature secondary processing. In order to obtain this effect, it must be more than 0.0002%. However, if the amount of B exceeds 0.0050%, hot workability will reduce. Therefore, when B is included, it is set to the range of 0.0002 to 0.0050%. Preferably, it is in the range of 0.0005 to 0.0035%. More preferably in the range of 0.0005 to 0.0020%.
REM:0.01~0.10% REM: 0.01~0.10%
REM係屬於提升耐氧化性的元素,特別係抑制熔接部的氧化皮膜形成而具有提升熔接部耐蝕性的效果。為能獲得此項效果必需含有達0.01%以上。但是,若含有超過0.10%,則會導致冷軋板退火時的酸洗性等製造性降低。又,因為REM係屬於高單價元素,因而過度含有反而會導致製造成本增加,故非屬較佳。所以,當含有REM的情況便設定為0.01~0.10%範圍。 REM is an element which enhances oxidation resistance, and particularly has an effect of suppressing formation of an oxide film in a welded portion and improving corrosion resistance of a welded portion. In order to obtain this effect, it must be more than 0.01%. However, when the content is more than 0.10%, the manufacturability such as pickling property during annealing of the cold-rolled sheet is lowered. Further, since REM is a high monovalent element, excessive inclusion may cause an increase in manufacturing cost, which is not preferable. Therefore, when REM is included, it is set to the range of 0.01 to 0.10%.
Ca:0.0002~0.0020% Ca: 0.0002~0.0020%
Ca係屬於防止因連續鑄造時較容易發生的Ti系夾雜物結晶,而造成噴嘴遭阻塞情況的有效成分。為能獲得此項效果必需含有達0.0002%以上。但是,若Ca量超過0.0020%,則會生成CaS導致耐蝕性降低。所以,當含有Ca的情況便設定為0.0002~0.0020%範圍。較佳係0.0005~0.0015%範圍。更佳係0.0005~0.0010%範圍。 The Ca system is an effective component for preventing the clogging of the Ti-based inclusions which are likely to occur during continuous casting, resulting in nozzle clogging. In order to obtain this effect, it must be more than 0.0002%. However, when the amount of Ca exceeds 0.0020%, CaS is generated to cause a decrease in corrosion resistance. Therefore, when Ca is contained, it is set in the range of 0.0002 to 0.0020%. Preferably, it is in the range of 0.0005 to 0.0015%. More preferably in the range of 0.0005 to 0.0010%.
其次,針對本發明肥粒鐵系不鏽鋼之製造方法進行說明。 Next, a method of producing the ferrite-based iron-based stainless steel of the present invention will be described.
本發明的肥粒鐵系不鏽鋼係將具有上述成分組成的鋼胚施行熱軋,接著施行依900~1000℃溫度範圍保持5秒~15分鐘的熱軋板退火,而形成熱軋退火板,接著經施行冷軋後,再施行依800~950℃溫度範圍保持5秒~5分鐘的冷軋板退火便可獲得。 The ferrite-based stainless steel of the present invention is subjected to hot rolling of a steel slab having the above composition, and then subjected to hot-rolled sheet annealing at a temperature ranging from 900 to 1000 ° C for 5 seconds to 15 minutes to form a hot rolled annealed sheet, and then After cold rolling, it can be obtained by annealing the cold rolled sheet at a temperature range of 800 to 950 ° C for 5 seconds to 5 minutes.
首先,利用轉爐、電爐、真空熔解爐等公知方法熔製由 上述成分組成構成的熔鋼,再利用連續鑄造法或鑄錠-塊料法形成鋼素材(鋼胚)。將該鋼胚依1100~1250℃加熱1~24小時、或在未加熱而保持鑄造狀態下直接施行熱軋而形成熱軋板。 First, it is melted by a known method such as a converter, an electric furnace, or a vacuum melting furnace. The molten steel composed of the above components is formed into a steel material (steel blank) by a continuous casting method or an ingot-block method. The steel preform is heated at 1100 to 1250 ° C for 1 to 24 hours, or directly subjected to hot rolling while being left unheated to form a hot rolled sheet.
其次,施行熱軋。捲取時較佳係將捲取溫度設定為500℃以上且850℃以下。若未滿500℃,則捲取後的再結晶不足會有導致經冷軋板退火後的延性降低之情況,故非屬較佳。若依超過850℃進行捲取,則粒徑會變大,會有在衝壓加工時發生表皮粗糙的情況。所以,捲取溫度較佳係500~850℃範圍。 Second, hot rolling is performed. It is preferable to set the coiling temperature to 500 ° C or more and 850 ° C or less at the time of coiling. If it is less than 500 ° C, the insufficient recrystallization after coiling may cause a decrease in ductility after annealing of the cold rolled sheet, which is not preferable. When the coiling is performed at a temperature exceeding 850 ° C, the particle diameter becomes large, and the skin may be rough during press working. Therefore, the coiling temperature is preferably in the range of 500 to 850 °C.
然後,施行依成為肥粒鐵相與沃斯田鐵相之雙相區域溫度的900~1000℃溫度,保持5秒~15分鐘的熱軋板退火。 Then, the hot-rolled sheet is annealed at a temperature of 900 to 1000 ° C which is a two-phase temperature of the iron phase of the ferrite grain and the iron phase of the Vostian, and is maintained for 5 seconds to 15 minutes.
其次,視需要施行酸洗、並施行冷軋及冷軋板退火。更進一步視需要施行酸洗便成為製品。 Secondly, pickling is carried out as needed, and cold rolling and cold rolled sheet annealing are performed. Further, as needed, pickling becomes a product.
就從拉伸性、彎曲性、衝壓成形性及形狀矯正的觀點,冷軋較佳係依達50%以上的軋縮率實施。又,本發明中,冷軋-退火亦可重複施行2次以上。 From the viewpoints of stretchability, bendability, press formability, and shape correction, cold rolling is preferably carried out at a rolling reduction ratio of 50% or more. Further, in the present invention, the cold rolling-annealing may be repeated twice or more.
為能獲得良好的成形性,冷軋板的退火係依800~950℃溫度保持5秒~5分鐘。又,為求更光澤亦可施行BA退火(輝面退火)。 In order to obtain good formability, the annealing of the cold-rolled sheet is maintained at a temperature of 800 to 950 ° C for 5 seconds to 5 minutes. Further, in order to obtain a more luster, BA annealing (gloss annealing) can be performed.
另外,為能更進一步提升表面性狀,亦可施行研削、研磨等。 In addition, in order to further improve the surface properties, grinding, polishing, and the like may be performed.
相關製造條件的較佳限定理由,說明如下。 The reasons for the better limitation of the relevant manufacturing conditions are as follows.
依900~1000℃溫度保持5秒~15分鐘的熱軋板退火 Hot-rolled sheet annealing at 900~1000 °C for 5 seconds to 15 minutes
熱軋板退火係本發明為能獲得優異成形性的極重要步驟。若熱軋板退火溫度未滿900℃,便不會生成充分的再結晶,且會成為肥粒鐵單相區域,因而無法獲得利用雙相區域退火顯現的本發明效果。但是, 若熱軋板退火溫度超過1000℃,則沃斯田鐵相的生成量會降低。所以,經熱軋板退火後所生成的麻田散鐵相量會減少,無法充分獲得藉由對含有肥粒鐵相與麻田散鐵相的金屬組織施行冷軋,而緩和因軋延應變集中於麻田散鐵相附近的肥粒鐵相,所造成金屬組織異向性的效果,造成無法獲得既定的|Δr|。若退火時間未滿5秒的情況,即便依既定溫度施行退火,仍無法充分產生沃斯田鐵相生成與肥粒鐵相再結晶,導致無法獲得所需成形性。另一方面,若退火時間超過15分鐘,則氮碳化鉻其中一部分會固溶,而助長沃斯田鐵相中的C濃化,導致經熱軋板退火後會發生由沃斯田鐵相變態生成的麻田散鐵相中過度C濃化。該麻田散鐵相在冷軋板退火時會分解為碳化物與肥粒鐵相,造成變化為含大量碳化物的肥粒鐵相。藉此,經冷軋板退火後的金屬組織,成為因為在熱軋板退火時係屬於肥粒鐵相因,而晶粒內及晶界上的碳化物較少之肥粒鐵粒,以及因為熱軋板退火時係屬於沃斯田鐵相,因而晶粒內及晶界上的碳化物過多的肥粒鐵粒之混粒組織。若成為此種金屬組織時,因為碳化物較少的晶粒與較多的晶粒會發生硬度差,造成成形時會在二者晶粒的界面處出現變形應變集中,導致容易以晶界上的碳化物為起點助長孔隙生成,造成延性降低。所以,熱軋板退火係依900~1000℃溫度保持5秒~15分鐘。較佳係依910~960℃溫度保持15秒~3分鐘。 Hot Rolled Sheet Annealing The present invention is an extremely important step for obtaining excellent formability. If the annealing temperature of the hot rolled sheet is less than 900 ° C, sufficient recrystallization will not be formed and it will become a single phase region of the ferrite iron, and thus the effect of the present invention which is exhibited by the annealing of the two-phase region cannot be obtained. but, If the annealing temperature of the hot rolled sheet exceeds 1000 ° C, the amount of formation of the Worth iron phase is lowered. Therefore, the amount of granules of the granulated iron produced by the annealing of the hot rolled sheet is reduced, and the cold rolling of the metal structure containing the ferrite phase and the granulated iron phase is not sufficiently obtained, and the strain is concentrated due to the rolling strain. The iron phase of the ferrite in the vicinity of the iron phase of the Ma Tian caused the anisotropy of the metal structure, resulting in the inability to obtain the established |Δr|. If the annealing time is less than 5 seconds, even if annealing is performed at a predetermined temperature, the formation of the iron phase of the Worth and the recrystallization of the iron phase of the ferrite are not sufficiently obtained, and the desired formability cannot be obtained. On the other hand, if the annealing time exceeds 15 minutes, a part of the chromium carbide will be solid solution, which will promote the concentration of C in the iron phase of the Vostian, resulting in the transformation of the iron phase by the Worthfield after the annealing of the hot rolled sheet. Excessive C concentration in the generated granulated iron phase. When the cold-rolled sheet is annealed, the granulated iron phase decomposes into a carbide-fat iron phase, causing a change to a ferrite-rich iron phase containing a large amount of carbide. Thereby, the metal structure after annealing of the cold-rolled sheet becomes a ferrite-grained iron grain which is a ferrite-grain-phase factor in the annealing of the hot-rolled sheet, and has less carbides in the grain and the grain boundary, and because When the hot-rolled sheet is annealed, it belongs to the iron phase of the Vostian, and thus the mixed structure of the ferrite-rich iron particles in the grains and on the grain boundaries is excessive. If it is such a metal structure, since the crystal grains with less carbides and the more crystal grains may have a hardness difference, deformation strain concentration occurs at the interface between the crystal grains at the time of forming, resulting in easy grain boundary The carbides act as a starting point to promote pore formation, resulting in reduced ductility. Therefore, the hot-rolled sheet annealing is maintained at a temperature of 900 to 1000 ° C for 5 seconds to 15 minutes. It is preferably maintained at a temperature of 910 to 960 ° C for 15 seconds to 3 minutes.
依800~950℃溫度保持5秒~5分鐘的冷軋板退火 Cold rolled sheet annealing at 800~950 °C for 5 seconds to 5 minutes
冷軋板退火係屬於為將依熱軋板退火所形成的肥粒鐵相與麻田散鐵相之雙相組織,形成肥粒鐵單相組織的重要步驟。若冷軋板退火溫度未滿800℃,則不會充分發生再結晶,導致無法獲得既定延性與平均r值。另一方面,當冷軋板退火溫度超過950℃的情況,若該溫度係成 為肥粒鐵相與沃斯田鐵相之雙相溫度區域的鋼成分,因為經冷軋板退火後會生成麻田散鐵相,因而鋼板會硬質化導致無法獲得既定延性。又,該溫度成為肥粒鐵單相溫度區域的鋼成分,亦會因結晶粒明顯粗大化,導致鋼板的光澤度降低,因而就表面品質的觀點非屬較佳。當退火時間未滿5秒的情況,即便依既定溫度施行退火仍不會充分發生肥粒鐵相的再結晶,因而導致無法獲得既定延性與平均r值。若退火時間超過5分鐘,則結晶粒會明顯粗大化,導致鋼板的光澤度降低,因而表面品質的觀點非屬較佳。所以,冷軋板退火係依800~950℃範圍保持5秒~5分鐘。較佳係依850℃~900℃保持15秒~3分鐘。 Cold-rolled sheet annealing belongs to the two-phase structure of the ferrite-iron phase formed by annealing the hot-rolled sheet and the granulated iron phase, forming an important step of the ferrite-iron single-phase structure. If the annealing temperature of the cold-rolled sheet is less than 800 ° C, recrystallization does not occur sufficiently, and the predetermined ductility and the average r value cannot be obtained. On the other hand, when the annealing temperature of the cold rolled sheet exceeds 950 ° C, if the temperature is The steel composition of the two-phase temperature region of the ferrite phase and the Worthite iron phase is formed by the annealing of the cold-rolled sheet, which results in the hardening of the steel sheet and the inability to obtain the desired ductility. Further, since this temperature becomes a steel component in the single-phase temperature region of the ferrite-rich iron, the crystal grain is remarkably coarsened, and the gloss of the steel sheet is lowered, so that the surface quality is not preferable. When the annealing time is less than 5 seconds, even if the annealing is performed at a predetermined temperature, the recrystallization of the ferrite iron phase does not sufficiently occur, and thus the predetermined ductility and the average r value cannot be obtained. When the annealing time exceeds 5 minutes, the crystal grains are significantly coarsened, and the gloss of the steel sheet is lowered, so that the viewpoint of surface quality is not preferable. Therefore, the cold rolled sheet annealing is maintained in the range of 800 to 950 ° C for 5 seconds to 5 minutes. Preferably, it is maintained at 850 ° C ~ 900 ° C for 15 seconds ~ 3 minutes.
以下,針對本發明利用實施例進行詳細說明。 Hereinafter, the present invention will be described in detail using an embodiment.
利用50kg小型真空熔解爐熔製具有表1所示化學組成的不鏽鋼鍋。該等鋼塊經利用1150℃加熱1小時後,施行熱軋而形成厚3.5mm的熱軋板。接著,對該等熱軋板依表2所記載條件施行熱軋板退火後,對表面施行珠粒噴擊處理與利用酸洗進行的脫銹皮。更進一步,施行冷軋直到板厚0.7mm為止後,再依表2所記載條件施行冷軋板退火後,施行利用酸洗進行的脫銹皮處理,便獲得冷軋酸洗退火板。 A stainless steel pot having the chemical composition shown in Table 1 was melted using a 50 kg small vacuum melting furnace. These steel blocks were heated at 1150 ° C for 1 hour, and then hot rolled to form a hot rolled sheet having a thickness of 3.5 mm. Next, the hot-rolled sheets were annealed by hot-rolled sheets according to the conditions described in Table 2, and then the surface was subjected to bead blasting treatment and derusting by pickling. Further, after cold rolling was performed until the thickness of the sheet was 0.7 mm, the cold-rolled sheet was annealed according to the conditions described in Table 2, and then subjected to descaling treatment by pickling to obtain a cold-rolled pickling-annealed sheet.
針對依此獲得的冷軋酸洗退火板施行以下的評價。 The following evaluation was performed on the cold-rolled pickling annealed sheet obtained in this manner.
(1)延性評價 (1) Ductility evaluation
從冷軋酸洗退火板朝L方向(軋延方向的平行方向)、D方向(軋延方向的45°方向)及C方向(軋延方向的直角方向)採取JIS 13B號拉伸試驗片,再根據JIS Z2241施行拉伸試驗,並測定斷裂拉伸,當各方向的斷裂拉伸達25%以上之情況便評為「合格(○)」,只要有其中一方向未 滿25%之情況便評為「不合格(×)」。 The JIS 13B tensile test piece was taken from the cold-rolled pickling-annealed sheet in the L direction (parallel direction in the rolling direction), the D direction (45° direction in the rolling direction), and the C direction (the direction perpendicular to the rolling direction). Then, according to JIS Z2241, a tensile test was carried out, and the tensile elongation was measured. When the tensile elongation in each direction was 25% or more, it was evaluated as "qualified (○)", as long as one of the directions was not If it is 25%, it will be rated as "failed (×)".
(2)平均r值及|Δr|的評價 (2) Evaluation of average r value and |Δr|
從冷軋酸洗退火板朝軋延方向的平行(L方向)、45°(D方向)及直角(C方向)方向採取JIS 13B號拉伸試驗片,再根據JIS Z2241施行拉伸試驗直到應變15%為止便中斷,測定各方向的r值,並計算出平均r值[=(rL+2rD+rC)/4]及r值的平面異向性[Δr=(rL-2rD+rC)/2]絕對值(|Δr|)。其中,rL、rD、rC分別係L方向、D方向及C方向的r值。若平均r值達0.70以上便評為「合格(○)」,若未滿0.70則評為「不合格(×)」。若|Δr|在0.20以下便評為「合格(○)」,若超過0.20便評為「不合格(×)」。 JIS 13B tensile test piece was taken from the cold-rolled pickling annealed sheet in the parallel (L direction), 45° (D direction) and right angle (C direction) directions of the rolling direction, and the tensile test was performed according to JIS Z2241 until strain 15% is interrupted, the r value in each direction is measured, and the average r value [=(r L +2r D +r C )/4] and the plane anisotropy of the r value are calculated [Δr=(r L -2r D +r C )/2] absolute value (|Δr|). Here, r L , r D , and r C are r values in the L direction, the D direction, and the C direction, respectively. If the average r value is 0.70 or more, it is rated as "qualified (○)", and if it is less than 0.70, it is rated as "failed (×)". If |Δr| is less than 0.20, it is rated as "acceptable (○)", and if it exceeds 0.20, it is rated as "failed (x)".
(3)耐蝕性評價 (3) Evaluation of corrosion resistance
從冷軋酸洗退火板採取60mm×100mm試驗片,表面經利用#600剛砂紙施行拋光加工後,製作端面部經密封的試驗片,提供進行JIS H 8502規定的鹽水噴霧循環試驗。鹽水噴霧循環試驗係以鹽水噴霧(5質量%NaCl、35℃、噴霧2h)→乾燥(60℃、4h、相對濕度40%)→濕潤(50℃、2h、相對濕度≧95%)為1循環,計施行8循環。 A 60 mm × 100 mm test piece was taken from the cold-rolled pickling annealed sheet, and the surface was subjected to a polishing process using #600 emery paper, and a test piece having a sealed end portion was prepared to provide a salt spray cycle test prescribed in JIS H 8502. The salt spray cycle test was carried out with salt spray (5 mass% NaCl, 35 ° C, spray 2 h) → dry (60 ° C, 4 h, relative humidity 40%) → wet (50 ° C, 2 h, relative humidity ≧ 95%) for 1 cycle , the implementation of 8 cycles.
針對經施行鹽水噴霧循環試驗計8循環後的試驗片表面拍攝照片,利用影像解析測定試驗片表面的生銹面積,從與試驗片總面積的比率計算出生銹面積率((試驗片中的生銹面積/試驗片總面積)×100[%])。生銹面積率在10%以下係屬於特別優異的耐蝕性,評為「合格(◎)」,超過10%且25%以下評為「合格(○)」,超過25%評為「不合格(×)」。 The photograph was taken on the surface of the test piece after 8 cycles of the salt spray test, and the rust area on the surface of the test piece was measured by image analysis, and the rust area ratio was calculated from the ratio of the total area of the test piece ((in the test piece) Rust area / total area of test piece) × 100 [%]). The rust area ratio of 10% or less is particularly excellent in corrosion resistance, and it is rated as "eligible (?)". More than 10% and 25% or less are rated as "qualified (○)", and more than 25% are rated as "unqualified ( ×)".
評價結果合併熱軋板退火與冷軋退火條件標示於表2中。 The evaluation results of the combined hot-rolled sheet annealing and cold-rolling annealing conditions are shown in Table 2.
鋼成分及製造方法均滿足本發明範圍的No.1~14、20~30及40~52,確認到斷裂拉伸達25%以上、平均r值達0.70以上、|Δr|在0.20以下的優異成形性。又,相關耐蝕性亦是獲得經實施鹽水噴霧循環試驗計8循環後,試驗片表面的生銹面積率均在25%以下的良好特性。 In the steel composition and the production method, No. 1 to 14, 20 to 30, and 40 to 52 which satisfy the scope of the present invention, it was confirmed that the tensile elongation at break was 25% or more, the average r value was 0.70 or more, and |Δr| was 0.20 or less. Formability. Further, the relevant corrosion resistance is also a good characteristic in which the rust area ratio of the surface of the test piece is 25% or less after 8 cycles of the salt spray test.
特別係Ni含有0.4%的鋼D與AC、Cu含有0.3%的鋼F、Cu含有0.4%的鋼AR、Mo含有0.3%的鋼G、及對應於鋼AI的No.4、No.22、No.6、No.50、No.7及No.41,經鹽水噴霧循環試驗後的生銹面積率在10%以下,或更加提升耐蝕性。 In particular, Ni contains 0.4% of steel D and AC, Cu contains 0.3% of steel F, Cu contains 0.4% of steel AR, Mo contains 0.3% of steel G, and No. 4 and No. 22 corresponding to steel AI. No. 6, No. 50, No. 7, and No. 41, the rust area ratio after the salt spray circulation test was 10% or less, or the corrosion resistance was further improved.
另一方面,Cr含有量低於本發明範圍的No.15,雖能獲得既定的延性、平均r值及|Δr|,但因為Cr含有量不足,因而無法獲得既定的耐蝕性。 On the other hand, in No. 15 in which the Cr content is lower than the range of the present invention, a predetermined ductility, an average r value, and |Δr| can be obtained, but since the Cr content is insufficient, a predetermined corrosion resistance cannot be obtained.
Cr含有量高於本發明範圍的No.16,雖能獲得充分的耐蝕性,但因為過剩含有Cr,因而在熱軋板退火時不會生成沃斯田鐵相,導致無法獲得既定的平均r值及|Δr|。 No. 16 having a Cr content higher than the range of the present invention can obtain sufficient corrosion resistance. However, since Cr is excessively contained, the Worstian iron phase is not formed during annealing of the hot rolled sheet, resulting in failure to obtain a predetermined average r. Value and |Δr|.
C量高於本發明範圍的No.17,雖能獲得既定的平均r值及|Δr|,但因為固溶C量增加,因而鋼板強度明顯提升,導致無法獲得既定的延性。 No. 17 having a C amount higher than the range of the present invention can obtain a predetermined average r value and |Δr|, but since the amount of solid solution C is increased, the strength of the steel sheet is remarkably improved, resulting in failure to obtain a predetermined ductility.
另一方面,C量低於本發明範圍的No.18,因為由C造成的沃斯田鐵相安定化不足,因而在熱軋板退火中不會生成足夠量的沃斯田鐵相,導致無法獲得既定的平均r值及|Δr|。 On the other hand, the amount of C is lower than No. 18 in the range of the present invention, because the iron phase stability of the Worth field caused by C is insufficient, so that a sufficient amount of the Worthfield iron phase is not generated in the hot-rolled sheet annealing, resulting in The given average r value and |Δr| cannot be obtained.
熱軋板退火溫度分別為875℃或871℃之偏低溫度的No.19或No.35,因為熱軋板退火溫度成為肥粒鐵單相溫度,導致成為沃斯田鐵相,因而經熱軋板退火後不會生成麻田散鐵相,導致無法獲 得緩和利用對含麻田散鐵的鋼板施行冷軋,而獲得既定金屬組織的異向性效果,造成無法獲得既定的|Δr|。熱軋板退火溫度分別為1014℃或1011℃之偏高溫度的No.31或No.36,在退火溫度中所生成的沃斯田鐵相量減少,經熱軋板退火後所生成的麻田散鐵相量減少,因而無法獲得緩和利用後續冷軋造成的既定金屬組織之異向性的效果,造成無法獲得既定的|Δr|。熱軋板退火時間為1秒鐘之偏短時間的No.32與No.37,因為沃斯田鐵相生成與不會生成足夠再結晶,因而無法獲得既定的延性、平均r值及|Δr|。冷軋板退火溫度為780℃之偏低溫度的No.33與No.38,不會充分生成再結晶,會殘存因冷軋造成的加工組織,結果造成無法獲得既定的延性及平均r值。冷軋板退火溫度為960℃之偏高溫度的No.34與No.39,在冷軋板退火時會再度生成沃斯田鐵相,於冷軋板退火後沃斯田鐵相會變態為麻田散鐵相,結果造成鋼板明顯硬質化,導致無法獲得既定的延性。又,因為經冷軋板退火後的組織含有麻田散鐵相,因而r值降低,無法獲得既定的平均r值。 The hot-rolled sheet annealing temperature is 875 ° C or 871 ° C low temperature No. 19 or No. 35, because the hot-rolled sheet annealing temperature becomes the ferrite-iron single-phase temperature, resulting in the Worstian iron phase, thus the heat After the annealing of the rolled sheet, no granulated iron phase will be formed, resulting in failure to obtain The steel sheet containing the granulated iron is subjected to cold rolling to obtain an anisotropic effect of a predetermined metal structure, so that a predetermined |Δr| cannot be obtained. The hot-rolled sheet annealing temperature is 1014 ° C or 1011 ° C, the high temperature of No. 31 or No. 36, the amount of Worstian iron phase generated in the annealing temperature is reduced, the hot field is annealed after the hot rolled sheet The amount of loose iron phasor is reduced, so that the effect of mitigating the anisotropy of a predetermined metal structure caused by subsequent cold rolling cannot be obtained, resulting in failure to obtain a predetermined |Δr|. The hot-rolled sheet annealing time is No. 32 and No. 37 of the short time of 1 second, because the formation of the iron phase of Vostian does not generate sufficient recrystallization, and thus the obtained ductility, average r value, and |Δr cannot be obtained. |. No. 33 and No. 38, which have a cold-rolled sheet annealing temperature of 780 ° C, are not sufficiently recrystallized, and the processed structure due to cold rolling remains, and as a result, a predetermined ductility and an average r value cannot be obtained. No.34 and No.39, which have a cold-rolled sheet annealing temperature of 960 °C, will regenerate the Worthfield iron phase when the cold-rolled sheet is annealed. After the cold-rolled sheet is annealed, the Worthite iron phase will be transformed into The iron phase of Ma Tian, resulting in the apparent hardening of the steel plate, led to the inability to obtain the established ductility. Further, since the microstructure after annealing of the cold-rolled sheet contains the granulated iron phase, the r value is lowered, and a predetermined average r value cannot be obtained.
由上述得知,為能獲得本發明所提供既定成形性,必需鋼成分及製造方法雙方均滿足本發明範圍。 From the above, it is known that both the steel component and the production method are required to satisfy the scope of the present invention in order to obtain the desired formability provided by the present invention.
本發明所獲得肥粒鐵系不鏽鋼,特別適用於以深衝為主體的衝壓成形品、要求高耐蝕性用途(例如建材、輸送機器、汽車零件)。 The ferrite-based iron-based stainless steel obtained by the present invention is particularly suitable for a press-formed product mainly composed of deep drawing, and is required for high corrosion resistance (for example, building materials, conveying equipment, and automobile parts).
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2015
- 2015-01-07 KR KR1020187029065A patent/KR20180114240A/en not_active Application Discontinuation
- 2015-01-07 WO PCT/JP2015/000033 patent/WO2015105046A1/en active Application Filing
- 2015-01-07 CN CN201580003658.0A patent/CN105874092A/en active Pending
- 2015-01-07 KR KR1020167021191A patent/KR20160105869A/en active Application Filing
- 2015-01-07 JP JP2015547587A patent/JP5987996B2/en active Active
- 2015-01-08 TW TW104100510A patent/TWI530571B/en active
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WO2015105046A1 (en) | 2015-07-16 |
KR20180114240A (en) | 2018-10-17 |
TW201529866A (en) | 2015-08-01 |
CN105874092A (en) | 2016-08-17 |
JPWO2015105046A1 (en) | 2017-03-23 |
KR20160105869A (en) | 2016-09-07 |
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