TW201843316A - Hot-rolled and annealed ferritic stainless steel sheet, and method for manufacturing same - Google Patents

Hot-rolled and annealed ferritic stainless steel sheet, and method for manufacturing same Download PDF

Info

Publication number
TW201843316A
TW201843316A TW107114282A TW107114282A TW201843316A TW 201843316 A TW201843316 A TW 201843316A TW 107114282 A TW107114282 A TW 107114282A TW 107114282 A TW107114282 A TW 107114282A TW 201843316 A TW201843316 A TW 201843316A
Authority
TW
Taiwan
Prior art keywords
hot
rolling
rolled
steel sheet
stainless steel
Prior art date
Application number
TW107114282A
Other languages
Chinese (zh)
Other versions
TWI685574B (en
Inventor
吉野正崇
井上佳士
藤澤光幸
Original Assignee
日商杰富意鋼鐵股份有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 日商杰富意鋼鐵股份有限公司 filed Critical 日商杰富意鋼鐵股份有限公司
Publication of TW201843316A publication Critical patent/TW201843316A/en
Application granted granted Critical
Publication of TWI685574B publication Critical patent/TWI685574B/en

Links

Classifications

    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21DMODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0205Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips of ferrous alloys
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B21MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21BROLLING OF METAL
    • B21B3/00Rolling materials of special alloys so far as the composition of the alloy requires or permits special rolling methods or sequences ; Rolling of aluminium, copper, zinc or other non-ferrous metals
    • B21B3/02Rolling special iron alloys, e.g. stainless steel
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21DMODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D6/00Heat treatment of ferrous alloys
    • C21D6/004Heat treatment of ferrous alloys containing Cr and Ni
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21DMODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D6/00Heat treatment of ferrous alloys
    • C21D6/005Heat treatment of ferrous alloys containing Mn
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21DMODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D6/00Heat treatment of ferrous alloys
    • C21D6/007Heat treatment of ferrous alloys containing Co
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21DMODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D6/00Heat treatment of ferrous alloys
    • C21D6/008Heat treatment of ferrous alloys containing Si
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21DMODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0221Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
    • C21D8/0226Hot rolling
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21DMODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0247Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
    • C21D8/0263Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment following hot rolling
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21DMODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0247Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
    • C21D8/0273Final recrystallisation annealing
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21DMODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D9/00Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/46Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for sheet metals
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • C22C38/001Ferrous alloys, e.g. steel alloys containing N
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • C22C38/002Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • C22C38/004Very low carbon steels, i.e. having a carbon content of less than 0,01%
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • C22C38/005Ferrous alloys, e.g. steel alloys containing rare earths, i.e. Sc, Y, Lanthanides
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • C22C38/02Ferrous alloys, e.g. steel alloys containing silicon
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • C22C38/04Ferrous alloys, e.g. steel alloys containing manganese
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • C22C38/06Ferrous alloys, e.g. steel alloys containing aluminium
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • C22C38/18Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/42Ferrous alloys, e.g. steel alloys containing chromium with nickel with copper
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • C22C38/18Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/44Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • C22C38/18Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/46Ferrous alloys, e.g. steel alloys containing chromium with nickel with vanadium
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • C22C38/18Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/48Ferrous alloys, e.g. steel alloys containing chromium with nickel with niobium or tantalum
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • C22C38/18Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/50Ferrous alloys, e.g. steel alloys containing chromium with nickel with titanium or zirconium
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • C22C38/18Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/52Ferrous alloys, e.g. steel alloys containing chromium with nickel with cobalt
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • C22C38/18Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/54Ferrous alloys, e.g. steel alloys containing chromium with nickel with boron
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21DMODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D2211/00Microstructure comprising significant phases
    • C21D2211/005Ferrite

Landscapes

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

Abstract

Provided are: a hot-rolled and annealed ferritic stainless steel sheet having a sufficient corrosion resistance, and capable of suppressing cracking while performing a punching process on a thick flange; and a method for manufacturing the same. The hot-rolled and annealed ferritic stainless steel sheet contains 0.00-0.020 mass% of C, 0.05-1.00 mass% of Si, 0.05-1.00 mass% of Mn, at most 0.04 mass% of P, at most 0.01 mass% of S, 0.001-0.100 mass% of Al, 10.0-19.0 mass% of Cr, 0.65-1.50 mass% of Ni, 0.10-0.40 mass% of Ti, and 0.001-0.020 mass% of N, and the remainder comprising Fe and inevitable impurities, wherein the threshold stress intensity factor KIC is at least 35 MPa.m1/2.

Description

肥粒鐵系不鏽鋼熱軋退火鋼板及其製造方法    Ferritic iron-based stainless steel hot-rolled annealed steel sheet and manufacturing method thereof   

本發明係關於一種適宜應用於凸緣等之加工性優異之肥粒鐵系不鏽鋼熱軋退火鋼板及其製造方法。 The present invention relates to a hot-rolled and annealed steel sheet of ferritic iron-based stainless steel with excellent processability suitable for flanges and the like, and a manufacturing method thereof.

近年來,關於汽車之排放氣體之法律規範不斷強化,燃油效率之提昇成為當務之急。因此,將自汽車引擎產生之排放氣體再次用作引擎之進氣的排放氣體再循環(Exhaust Gas Recirculation,EGR)系統之應用正不斷發展。自引擎產生之排放氣體通過用以降低氣體溫度之EGR冷卻器後被再次供給至引擎。使排放氣體循環時,各排氣系統零件經由凸緣而緊固以防氣體洩漏。應用於此種排氣系統零件之凸緣必須具有充分之剛性。因此,對此種排氣系統零件應用厚壁(例如,板厚為5mm以上)之凸緣。 In recent years, laws and regulations on automobile exhaust gas have been continuously strengthened, and the improvement of fuel efficiency has become a top priority. Therefore, the application of the exhaust gas recirculation (EGR) system that uses the exhaust gas generated from the automobile engine as the intake air of the engine is being continuously developed. The exhaust gas generated from the engine is supplied to the engine again after passing through an EGR cooler for reducing the gas temperature. When the exhaust gas is circulated, each exhaust system part is fastened via a flange to prevent gas leakage. The flanges used in such exhaust system parts must be sufficiently rigid. Therefore, a thick-walled flange (for example, a plate thickness of 5 mm or more) is applied to such an exhaust system part.

習知,厚壁凸緣一直使用普通鋼。然而,對應用於如EGR系統之使高溫之排放氣體通過之零件的凸緣要求充分之耐蝕性。因此,研究了與普通鋼相比耐蝕性優異之不鏽鋼、尤其是熱膨脹率相對較小而不易產生熱應力之肥粒鐵系不鏽鋼之應用,強烈要求能夠應用於厚壁凸緣之板厚較大(例如,板厚為5mm以上)之肥粒鐵系不鏽鋼板。 Conventionally, thick steel flanges have always used ordinary steel. However, flanges corresponding to parts for passing high-temperature exhaust gas such as an EGR system require sufficient corrosion resistance. Therefore, the application of stainless steels with superior corrosion resistance compared to ordinary steels, especially ferrous iron-based stainless steels with relatively small thermal expansion coefficients that are not prone to thermal stress, has been studied, and it is strongly required that they can be applied to thicker flanges with larger plate thicknesses. (For example, a plate thickness of 5 mm or more) a ferrous iron-based stainless steel plate.

針對此種市場需求,例如於專利文獻1中揭示有一種肥粒鐵系不鏽鋼熱軋鋼板,其以質量%計,含有:C:0.015%以下、 Si:0.01~0.4%、Mn:0.01~0.8%、P:0.04%以下、S:0.01%以下、Cr:14.0~未滿18.0%、Ni:0.05~1%、Nb:0.3~0.6%、Ti:0.05%以下、N:0.020%以下、Al:0.10%以下、B:0.0002~0.0020%且剩餘部分為Fe及不可避免之雜質,Nb、C及N之含量滿足Nb/(C+N)≧16,0℃下之夏比衝擊值為10J/cm2以上,板厚為5.0~9.0mm。 In response to this market demand, for example, Patent Document 1 discloses a ferritic iron-based stainless steel hot-rolled steel sheet, which, in terms of mass%, contains: C: 0.015% or less, Si: 0.01-0.4%, and Mn: 0.01-0.8 %, P: 0.04% or less, S: 0.01% or less, Cr: 14.0 to less than 18.0%, Ni: 0.05 to 1%, Nb: 0.3 to 0.6%, Ti: 0.05% or less, N: 0.020% or less, Al : 0.10% or less, B: 0.0002 to 0.0020% and the remainder is Fe and inevitable impurities. The content of Nb, C, and N satisfies Nb / (C + N) ≧ 16, and the Charpy impact value at 0 ℃ is 10J. / cm 2 or more, the thickness is 5.0 ~ 9.0mm.

[先前技術文獻]     [Prior technical literature]     [專利文獻]     [Patent Literature]    

專利文獻1:國際公開第2014/157576號 Patent Document 1: International Publication No. 2014/157576

然而,本發明人等嘗試了使用專利文獻1中記載之肥粒鐵系不鏽鋼熱軋鋼板加工成具有去毛刺加工部之厚壁凸緣形狀,結果發現到,儘管上述鋼板具有充分之夏比衝擊值,但仍存在於去毛刺(burring)加工部尤其是板厚中央部產生破裂而無法獲得既定凸緣形狀之情況,對應用於厚壁凸緣而言不充分。 However, the present inventors have attempted to use a ferrous-iron-based stainless steel hot-rolled steel sheet described in Patent Document 1 to form a thick-walled flange shape having a deburred portion, and have found that, although the steel sheet has a sufficient Charpy impact Value, but there are cases where cracking occurs in the burring processed portion, especially in the center of the plate thickness, and a predetermined flange shape cannot be obtained, which is not sufficient for thick-walled flanges.

本發明之目的在於解決該課題,提供一種具有充分之耐蝕性並且能夠抑制衝孔加工成厚壁凸緣時之破裂的肥粒鐵系不鏽鋼熱軋退火鋼板及其製造方法。 An object of the present invention is to solve this problem, and to provide a ferritic iron-based stainless steel hot-rolled and annealed steel sheet having sufficient corrosion resistance and capable of suppressing cracking when punched into a thick-walled flange and a method for manufacturing the same.

本發明人等為了解決上述課題而進行了詳細研究,結果發現,為了不產生破裂並加工成具有去毛刺加工部之厚壁凸緣,只要增大鋼板之低限應力強度因數KIC即可。具體而言,發現藉由 將低限應力強度因數KIC設為35MPa.m1/2以上,能夠有效地抑制加工成具有去毛刺加工部之厚壁凸緣時於去毛刺加工部產生破裂,而能夠充分地實際應用於具有去毛刺加工部之厚壁凸緣。 The present inventors conducted detailed studies in order to solve the above-mentioned problems, and as a result, found that in order to prevent cracking and process into a thick-walled flange having a deburred portion, it is only necessary to increase the low limit stress intensity factor K IC of the steel sheet. Specifically, it was found that by setting the low limit stress intensity factor K IC to 35 MPa. M 1/2 or more can effectively suppress the occurrence of cracks in the deburring portion when being processed into a thick-walled flange having a deburring portion, and can be fully practically applied to a thick-walled flange having a deburring portion.

而且,發現:藉由以適當溫度對如下熱軋鋼板進行熱軋板退火,低限應力強度因數KIC提昇,該熱軋鋼板係針對適當成分之肥粒鐵系不鏽鋼,適當控制尤其是包含3道以上之多道之精熱軋中之最終3道之累積軋縮率(=100-(最終板厚/最終3道之軋壓開始前之板厚)×100[%])而獲得。本發明係基於以上之見解而成者,主旨如下。 Furthermore, it was found that by performing hot-rolled sheet annealing on the following hot-rolled steel sheet at an appropriate temperature, the low limiting stress intensity factor K IC was improved. The hot-rolled steel sheet is a ferritic iron-based stainless steel with an appropriate composition, and the appropriate control includes 3 The cumulative rolling reduction rate of the final 3 passes in the multi-pass finishing hot rolling (= 100- (final sheet thickness / plate thickness before the rolling start of the last 3 passes) × 100 [%]) is obtained. This invention is based on the above knowledge, The summary is as follows.

[1]一種肥粒鐵系不鏽鋼熱軋退火鋼板,其具有以質量%計,含有:C:0.001~0.020%、Si:0.05~1.00%、Mn:0.05~1.00%、P:0.04%以下、S:0.01%以下、Al:0.001~0.100%、Cr:10.0~19.0%、Ni:0.65~1.50%、Ti:0.10~0.40%、N:0.001~0.020%且剩餘部分包含Fe及不可避免之雜質的成分組成,低限應力強度因數KIC為35MPa.m1/2以上。 [1] A ferritic iron-based stainless steel hot-rolled annealed steel sheet, which has a mass% of: C: 0.001 to 0.020%, Si: 0.05 to 1.00%, Mn: 0.05 to 1.00%, P: 0.04% or less, S: 0.01% or less, Al: 0.001 to 0.100%, Cr: 10.0 to 19.0%, Ni: 0.65 to 1.50%, Ti: 0.10 to 0.40%, N: 0.001 to 0.020% and the remainder contains Fe and unavoidable impurities The composition of the composition, the low limit stress intensity factor K IC is 35MPa. m 1/2 or more.

[2]如[1]中記載之肥粒鐵系不鏽鋼熱軋退火鋼板,其中上述成分組成以質量%計進而含有選自Cu:0.01~1.00%、Mo:0.01~2.00%、W:0.01~0.20%、Co:0.01~0.20%中之1種或2種以上。 [2] The ferritic iron-based stainless steel hot-rolled annealed steel sheet according to [1], wherein the above-mentioned component composition is further selected from Cu: 0.01 to 1.00%, Mo: 0.01 to 2.00%, and W: 0.01 to 0.20%, Co: One or more of 0.01 to 0.20%.

[3]如[1]或[2]中記載之肥粒鐵系不鏽鋼熱軋退火鋼板,其中上述成分組成以質量%計,進而含有:選自V:0.01~0.20%、Nb:0.01~0.10%、Zr:0.01~0.20%、REM:0.001~0.100%、B:0.0002~0.0025%、Mg:0.0005~0.0030%、Ca:0.0003~0.0030%中之1種或2種以上。 [3] The ferritic iron-based stainless steel hot-rolled annealed steel sheet according to [1] or [2], wherein the above-mentioned component composition is measured in mass% and further contains: selected from V: 0.01 to 0.20%, Nb: 0.01 to 0.10 %, Zr: 0.01 ~ 0.20%, REM: 0.001 ~ 0.100%, B: 0.0002 ~ 0.0025%, Mg: 0.0005 ~ 0.0030%, Ca: 0.0003 ~ 0.0030%.

[4]一種肥粒鐵系不鏽鋼熱軋退火鋼板之製造方法,其係如[1]至[3]中任一項中記載之肥粒鐵系不鏽鋼熱軋退火鋼板之製造方法,其具有進行3道以上之精軋之熱軋步驟;及對藉由該熱軋步驟所獲得之熱軋鋼板以600℃~1100℃進行熱軋板退火之熱軋板退火步驟,於上述熱軋步驟中,針對精軋之最終3道,將溫度設為800~1100℃且將上述最終3道之累積軋縮率設為25%以上。 [4] A method for manufacturing a hot-rolled and annealed steel sheet of a ferrous iron-based stainless steel, which is a method for manufacturing a hot-rolled and annealed steel sheet of a ferrous iron-based stainless steel as described in any one of [1] to [3], which includes: 3 or more hot rolling steps for finishing rolling; and a hot-rolled sheet annealing step of hot-rolled sheet annealing of the hot-rolled steel sheet obtained by the hot-rolling step at 600 ° C to 1100 ° C. In the above-mentioned hot-rolling step, For the last three passes of finishing rolling, the temperature is set to 800 to 1100 ° C and the cumulative rolling reduction rate of the last three passes is set to 25% or more.

此處,低限應力強度因數KIC係指藉由以疲勞預裂成為軋壓直角方向、應力軸成為軋壓平行方向之方式自板寬中央部採取依據ASTM E399之CT試片,並依據ASTM E399進行試驗而獲得之應力強度因數。 Here, the low limit stress intensity factor K IC refers to a CT test piece according to ASTM E399 taken from the center of the plate width by means of fatigue pre-splitting to become a right-angle direction of rolling and a stress axis to a parallel direction of rolling, and according to ASTM E399 The stress intensity factor obtained from the test.

根據本發明,可獲得具有充分之耐蝕性並且能夠抑制衝孔加工成厚壁凸緣時之破裂的韌性優異之肥粒鐵系不鏽鋼熱軋退火鋼板。 According to the present invention, a ferritic iron-based stainless steel hot-rolled annealed steel sheet having sufficient corrosion resistance and excellent toughness capable of suppressing cracking when punched into a thick-walled flange can be obtained.

再者,本發明中之充分之耐蝕性係指針對利用#600砂紙對表面進行研磨整飾後將端面部密封而成之鋼板,將JIS H 8502中規定之鹽水噴霧循環試驗(將鹽水噴霧(5質量%NaCl、35℃、噴霧2hr)→乾燥(60℃、4hr、相對濕度40%)→濕潤(50℃、2hr、相對濕度≧95%))作為1個循環之試驗)進行5個循環之情況時,鋼板表面之生鏽面積率(=生鏽面積/鋼板總面積×100[%])為25%以下。 In addition, the sufficient corrosion resistance in the present invention refers to a steel plate formed by sealing the end surface after grinding and finishing the surface with # 600 sandpaper, and subjected to a salt water spray cycle test specified in JIS H 8502 (spray salt water ( 5 mass% NaCl, 35 ° C, spray for 2hr) → dry (60 ° C, 4hr, relative humidity 40%) → wet (50 ° C, 2hr, relative humidity ≧ 95%)) as a cycle test) 5 cycles In this case, the rust area ratio of the steel plate surface (= rust area / total steel plate area × 100 [%]) is 25% or less.

又,所謂能夠抑制衝孔加工成厚壁凸緣時之破裂的優異韌性,係指藉由以疲勞預裂成為軋壓直角方向、應力軸成為軋壓平行方向之方式自板寬中央部採取依據ASTM E399之CT試片, 並依據ASTM E399進行試驗而獲得之低限應力強度因數KIC為35MPa.m1/2以上。 In addition, the excellent toughness capable of suppressing cracking when punching into a thick-walled flange refers to the basis from the center of the plate width by means of fatigue pre-splitting to become the right-angle direction of rolling and the stress axis to be the parallel direction of rolling. The low limit stress intensity factor K IC of the CT test piece of ASTM E399 and the test according to ASTM E399 is 35MPa. m 1/2 or more.

以下,對本發明之實施形態進行說明。再者,本發明並不限定於以下之實施形態。 Hereinafter, embodiments of the present invention will be described. The present invention is not limited to the following embodiments.

本發明之肥粒鐵系不鏽鋼熱軋退火鋼板具有以質量%計,含有:C:0.001~0.020%、Si:0.05~1.00%、Mn:0.05~1.00%、P:0.04%以下、S:0.01%以下、Al:0.001~0.100%、Cr:10.0~19.0%、Ni:0.65~1.50%、Ti:0.10~0.40%、N:0.001~0.020%且剩餘部分包含Fe及不可避免之雜質的成分組成,低限應力強度因數KIC為35MPa.m1/2以上。 The ferritic iron-based stainless steel hot-rolled and annealed steel sheet of the present invention has a mass percentage of C: 0.001 to 0.020%, Si: 0.05 to 1.00%, Mn: 0.05 to 1.00%, P: 0.04% or less, and S: 0.01. % Or less, Al: 0.001 to 0.100%, Cr: 10.0 to 19.0%, Ni: 0.65 to 1.50%, Ti: 0.10 to 0.40%, N: 0.001 to 0.020%, and the remainder contains Fe and unavoidable impurity composition , The low limit stress intensity factor K IC is 35MPa. m 1/2 or more.

低限應力強度因數KIC係指藉由以疲勞預裂成為軋壓直角方向、應力軸成為軋壓平行方向之方式自板寬中央部採取依據ASTM E399之CT試片,並依據ASTM E399進行試驗而獲得之應力強度因數。 The lower limit stress intensity factor K IC refers to a CT test piece according to ASTM E399 from the center of the plate width by means of fatigue pre-cracking to become a right-angle direction of rolling and a stress axis to a parallel direction of rolling, and the test is performed according to ASTM E399. The obtained stress intensity factor.

以下,對本發明進行詳細說明。 Hereinafter, the present invention will be described in detail.

本發明人等對使用板厚5.0mm之各種肥粒鐵系不鏽鋼鋼板成形為如下凸緣時產生破裂之原因進行了詳細研究,該凸緣具有將30mm 之凸緣孔部自胚料之鋼板表面上拉10mm之去毛刺加工部。其結果,查明於產生破裂之上述鋼板中,衝孔端面之板厚中央部附近產生之微小龜裂於去毛刺加工中顯著擴展而產生破裂。 The present inventors have studied in detail the causes of cracking when forming various ferritic iron-based stainless steel plates with a thickness of 5.0 mm into a flange having a thickness of 30 mm The flange hole portion is pulled from the surface of the steel plate of the blank by a deburring processing portion of 10 mm. As a result, it was found that in the above-mentioned steel sheet where cracks occurred, the minute cracks generated near the central portion of the thickness of the punched end face significantly expanded during deburring and cracked.

本發明人等對該微小龜裂之顯著擴展與材料特性之 關係進行了詳細研究。其結果,查明微小龜裂之擴展具有鋼板之低限應力強度因數越小則越容易產生之傾向。因此,嘗試了使用各種肥粒鐵系不鏽鋼熱軋退火鋼板(板厚5.0mm)成形為該凸緣,結果發現因微小龜裂之擴展引起之破裂於藉由既定測定方法所得之低限應力強度因數低於35MPa.m1/2之鋼板中尤其容易產生。 The inventors of the present invention conducted a detailed study on the relationship between the significant expansion of the tiny cracks and the material properties. As a result, it has been found that the propagation of minute cracks tends to occur more easily as the lower the lower limit stress intensity factor of the steel sheet. Therefore, attempts have been made to form this flange using various ferritic iron-based stainless steel hot-rolled annealed steel plates (sheet thickness 5.0mm). As a result, it was found that the cracks caused by the propagation of microcracks were caused by the low limit stress intensity obtained by a predetermined measurement method. The factor is lower than 35MPa. It is particularly easy to occur in a steel plate of m 1/2 .

進而,本發明人等為了使於成形為該凸緣時產生破裂之鋼板之低限應力強度因數較小之原因更明確,而對上述鋼板之破裂部進行了詳細調查。其結果,查明於產生破裂之鋼板中,衝孔端面之板厚中央部附近產生之龜裂於板厚中央部附近之晶界中顯著擴展。 Furthermore, the present inventors have conducted detailed investigations into the cracked portion of the steel sheet in order to make the cause of the low stress stress factor of the steel sheet cracked during the forming of the flange clearer. As a result, it was found that, in the steel sheet where cracks occurred, cracks generated near the central part of the plate thickness of the punched end face significantly expanded in the grain boundaries near the central part of the plate thickness.

而且,藉由SEM/EBSD法[掃描式電子顯微鏡(SEM,scanning electron microscope)/電子反向散射繞射(EBSD,Electron Backscatter Diffraction)法]對上述鋼板之組織進行調查、分析,結果查明龜裂顯著擴展之部位之結晶粒雖為各自獨立之結晶粒,但形成了與相鄰之結晶粒具有大致相同之結晶方位之所謂聚落(colony,具有類似結晶方位之結晶粒群)。一般而言,結晶粒具有與相鄰之結晶粒不同之結晶方位,當龜裂於晶界上擴展時,方位不同之晶界發揮作為龜裂擴展之障礙功能。然而,於聚落中相鄰之結晶粒之結晶方位大致相等,因此由聚落內之各結晶粒間之晶界產生之龜裂擴展之抑制效果變小。藉此查明,於形成有聚落之鋼板中,低限應力強度因數下降,而於成形為該凸緣時產生破裂。 Furthermore, the SEM / EBSD method [scanning electron microscope (SEM) / Electron Backscatter Diffraction (EBSD) method] was used to investigate and analyze the structure of the steel sheet, and as a result, the turtle was identified. Although the crystal grains at the locations where the cracks are significantly expanded are independent crystal grains, so-called colonies (groups of crystal grains with similar crystal orientations) having approximately the same crystal orientation as adjacent crystal grains are formed. Generally speaking, crystal grains have different crystal orientations from adjacent crystal grains. When cracks propagate on grain boundaries, grain boundaries with different orientations play a barrier function as crack propagation. However, the crystal orientations of adjacent crystal grains in the settlement are approximately equal, so the effect of suppressing the crack propagation from the grain boundary between the crystal grains in the settlement becomes smaller. As a result, it was found that in the steel sheet on which the settlements were formed, the low-limit stress intensity factor decreased, and cracking occurred when the flange was formed into the flange.

因此,本發明人等對提昇肥粒鐵系不鏽鋼熱軋退火鋼板中之低限應力強度因數之方法進行了努力研究。其結果,發現藉由以600℃~1100℃對如下熱軋鋼板進行熱軋板退火,可有效地破 壞聚落,而獲得35MPa.m1/2以上之低限應力強度因數KIC,該熱軋鋼板係在包含多道之精軋之最終3道之溫度為800~1100℃且最終3道之累積軋縮率(=100-(最終板厚/最終3道之軋壓開始前之板厚)×100[%])為25%以上之條件下對適當成分之肥粒鐵系不鏽鋼進行熱軋而獲得。 Therefore, the present inventors have worked hard on a method for improving the low-limit stress intensity factor in a hot-rolled and annealed steel sheet of ferritic iron-based stainless steel. As a result, it was found that by performing hot-rolled sheet annealing on the following hot-rolled steel sheets at 600 ° C to 1100 ° C, the aggregation can be effectively destroyed, and 35 MPa was obtained. Low limit stress intensity factor K IC above m 1/2 , the hot-rolled steel sheet has a final rolling temperature of 800 ~ 1100 ° C and a cumulative rolling reduction of the final 3 passes (= 100- (Final sheet thickness / thickness before the start of rolling in the last 3 passes) × 100 [%]) is obtained by hot-rolling a ferrous iron-based stainless steel with an appropriate composition under conditions of 25% or more.

再者,本發明之肥粒鐵系不鏽鋼熱軋退火鋼板之板厚並無特別限定,較理想為能夠應用於厚壁凸緣之板厚。關於下限,板厚較佳為5.0mm以上。更佳為9.0mm以上。關於上限,較佳為15.0mm以下。更佳為10.0mm以下。 In addition, the thickness of the ferritic iron-based stainless steel hot-rolled annealed steel sheet of the present invention is not particularly limited, and it is preferable that the sheet thickness can be applied to a thick-walled flange. The lower limit is preferably 5.0 mm or more. More preferably, it is 9.0 mm or more. The upper limit is preferably 15.0 mm or less. More preferably, it is 10.0 mm or less.

以下,對藉由上述方法促進聚落之破壞之理由進行說明。 The reason for promoting the destruction of the settlement by the above method will be described below.

於肥粒鐵系不鏽鋼之熱軋前之鋼坯之板厚中央部,粗大且延展之聚落(具有類似結晶方位之結晶粒群)沿鑄造方向相連分佈。另一方面,於對鋼板進行軋壓之情況時,鋼板自表層部發生變形而伸長。因此,於軋縮率較小之情況時,板厚中央部之變形量變小,於板厚中央部幾乎未導入軋壓應變。其結果,於利用習知技術之熱軋中,於鋼板之板厚中央部之延展粒未充分導入軋壓應變,而其後之熱軋板退火中之再結晶位置不足,於熱軋板退火時,雖於板厚中央附近產生再結晶,但聚落未被分離而容易殘留,而無法獲得本發明所需之35MPa.m1/2以上之低限應力強度因數KICAt the central part of the thickness of the slab before hot rolling of the ferrous iron-based stainless steel, coarse and extended settlements (groups of crystal grains with similar crystal orientation) are continuously distributed along the casting direction. On the other hand, when the steel sheet is rolled, the steel sheet is deformed from the surface layer portion and elongated. Therefore, when the reduction ratio is small, the amount of deformation in the center portion of the plate thickness becomes small, and rolling strain is hardly introduced in the center portion of the plate thickness. As a result, in the hot rolling using the conventional technology, the rolling grains in the central portion of the thickness of the steel sheet were not sufficiently introduced with rolling strain, and the recrystallization position in the subsequent hot rolling annealing was insufficient, and the hot rolling was annealed. At this time, although recrystallization occurred near the center of the plate thickness, the settlement was not separated and easily remained, and the 35 MPa required by the present invention could not be obtained. Low limit stress intensity factor K IC above m 1/2 .

進而,肥粒鐵系不鏽鋼於熱軋中幾乎不產生動態再結晶,具有容易產生因軋壓引起之加工應變恢復的傾向。因此,於利用習知技術之熱軋中,產生藉由軋壓導入之加工應變之過度恢復,而無法有效地維持加工應變直至熱軋後。其結果,再結晶位置變得 不充分,於後續步驟之熱軋板退火中,聚落未被有效地破壞,從而無法獲得既定之低限應力強度因數KICFurthermore, ferritic iron-based stainless steel hardly undergoes dynamic recrystallization during hot rolling, and tends to easily recover the processing strain due to rolling. Therefore, in the hot rolling using the conventional technology, excessive recovery of the processing strain introduced by rolling is generated, and the processing strain cannot be effectively maintained until after the hot rolling. As a result, the recrystallization position becomes insufficient, and in the hot-rolled sheet annealing in the subsequent step, the settlement is not effectively destroyed, and the predetermined low-limit stress intensity factor K IC cannot be obtained.

因此,本發明人等針對有效減少於熱軋板退火後殘留之聚落之方法,自鋼成分及熱軋方法之兩方面進行了努力研究。其結果,發現有效的是:將鋼成分、尤其是Cr及Ni之含量控制於適當之範圍而於熱軋步驟中生成既定量之沃斯田鐵相,並且將熱軋步驟中之精熱軋之最終3道管理於適當之溫度範圍,在此基礎上,以較大之累積軋縮率進行軋壓。 Therefore, the present inventors have worked hard on two aspects of the steel composition and the hot rolling method for a method for effectively reducing the accumulation of residuals after annealing of the hot rolled sheet. As a result, it was found that it is effective to control the content of steel components, especially Cr and Ni to an appropriate range, to generate a predetermined amount of Wastfield iron phase in the hot rolling step, and to finish hot rolling in the hot rolling step. The final 3 passes are managed in an appropriate temperature range, and on this basis, rolling is performed with a larger cumulative rolling reduction rate.

藉此,能夠藉由沃斯田鐵相之生成破壞鑄造時所形成之聚落,並且於熱軋中抑制軋壓加工應變之恢復且將軋壓加工應變充分且有效地導入至板厚之中央部。藉此,能夠獲得於熱軋後殘留之形成於鑄造時之聚落較習知技術格外少,且使成為後續步驟之熱軋板退火中之再結晶位置之軋壓加工應變充分殘留的熱軋板組織。其結果,於後續步驟之熱軋板退火中,聚落被更有效地消除,而獲得優異之低限應力強度因數。 This makes it possible to destroy the aggregates formed during casting by the generation of the vostian iron phase, and to suppress the recovery of the rolling process strain during hot rolling, and to sufficiently and effectively introduce the rolling process strain to the center of the plate thickness. . Thereby, it is possible to obtain a hot-rolled sheet remaining after hot rolling, which has fewer settlements formed during casting than conventional techniques, and which allows sufficient residual rolling strain at the recrystallization position in the annealing of the hot-rolled sheet in the subsequent steps. organization. As a result, in the hot-rolled sheet annealing in the subsequent step, the settlement is more effectively eliminated, and an excellent low-limit stress intensity factor is obtained.

具體而言,提案出:針對為了於熱軋前之加熱時生成沃斯田鐵相而將Cr含量調整為10.0~19.0%之範圍且將Ni含量調整為0.65~1.50%之範圍之鋼,以包含3道以上之精熱軋之最終3道之溫度成為800~1100℃且最終3道之累積軋縮率(=100-(最終板厚/最終3道之軋壓開始前之板厚)×100[%])成為25%以上之方式進行適當控制而進行熱軋。 Specifically, it is proposed that for steels whose Cr content is adjusted to be in the range of 10.0 to 19.0% and Ni content is to be adjusted to be in the range of 0.65 to 1.50% in order to generate a Wastfield iron phase during heating before hot rolling, The temperature of the last 3 passes including 3 or more finish hot rolling becomes 800 ~ 1100 ° C and the cumulative rolling reduction of the last 3 passes (= 100- (final sheet thickness / plate thickness before the start of rolling of the last 3 passes) × 100 [%]) is controlled to be 25% or more, and hot rolling is performed by appropriate control.

又,本發明人等亦對後續步驟之熱軋板退火之較佳之條件進行了努力研究。熱軋板退火係使藉由熱軋形成之加工組織再結晶之步驟。因此,必須以產生充分之再結晶之溫度進行退火。然 而,於以過度之高溫進行熱軋板退火之情況時,雖產生再結晶,但產生再結晶粒之顯著粗大化。該顯著粗大之再結晶粒雖為獨立之單一結晶粒,但晶界長度顯著變長。因此,發現由方位不同之晶界產生之龜裂擴展之抑制效果與存在聚落之情況同樣地下降,而無法獲得既定之低限應力強度因數。 In addition, the present inventors have also worked hard on better conditions for annealing the hot-rolled sheet in the subsequent steps. Hot-rolled sheet annealing is a step of recrystallizing a processed structure formed by hot rolling. Therefore, annealing must be performed at a temperature that produces sufficient recrystallization. However, in the case where the hot-rolled sheet is annealed at an excessively high temperature, although recrystallization occurs, recrystallization grains are significantly coarsened. Although the significantly coarse recrystallized grains are independent single crystal grains, the grain boundary length becomes significantly longer. Therefore, it was found that the effect of suppressing crack propagation from grain boundaries with different orientations was reduced as in the case of settlement, and it was impossible to obtain a predetermined low limit stress intensity factor.

因此,本發明人等對再結晶粒之粒徑與退火溫度之關係進行了詳細調查。其結果,發現藉由將熱軋板退火溫度控制為1100℃以下,而可抑制粗大之再結晶粒之生成,藉此可獲得良好之低限應力強度因數。 Therefore, the present inventors investigated the relationship between the particle diameter of the recrystallized grains and the annealing temperature in detail. As a result, it was found that by controlling the annealing temperature of the hot-rolled sheet to 1100 ° C. or less, the generation of coarse recrystallized grains can be suppressed, thereby obtaining a good low-limit stress intensity factor.

其次,對本發明之肥粒鐵系不鏽鋼熱軋退火鋼板之成分組成進行說明。 Next, the component composition of the ferritic iron-based stainless steel hot-rolled annealed steel sheet of the present invention will be described.

以下,只要未特別說明,成分之含量之單位的「%」係指「質量%」。 Hereinafter, unless otherwise specified, the unit "%" of the content of the ingredients means "mass%".

C:0.001~0.020% C: 0.001 ~ 0.020%

若含有C超過0.020%,則加工性之下降及焊接部之耐蝕性下降變得顯著。就耐蝕性及加工性之觀點而言,C含量越少則越佳,但為了使C含量未滿0.001%,需要於精煉上耗費時間,而於製造上欠佳。因此,C含量係設為0.001~0.020%之範圍。關於下限,較佳為C含量為0.003%以上,更佳為0.004%以上。關於上限,較佳為0.015%以下,進而較佳為0.012%以下。 When C is contained in an amount exceeding 0.020%, a decrease in workability and a decrease in corrosion resistance of a welded portion become significant. From the viewpoint of corrosion resistance and processability, the smaller the C content, the better, but in order to make the C content less than 0.001%, it takes time for refining, and it is not good for manufacturing. Therefore, the C content is set in the range of 0.001 to 0.020%. Regarding the lower limit, the C content is preferably 0.003% or more, and more preferably 0.004% or more. The upper limit is preferably 0.015% or less, and more preferably 0.012% or less.

Si:0.05~1.00% Si: 0.05 ~ 1.00%

Si係具有濃縮為焊接時所形成之氧化皮膜而提昇焊接部之耐 蝕性的效果,並且作為製鋼步驟中之脫氧元素亦有用之元素。該等效果係藉由含有0.05%以上之Si而獲得,含量越多,則該等效果越大。然而,若含有Si超過1.00%,則分別產生熱軋步驟中之軋壓負重之增大及顯著之鏽皮生成、以及退火步驟中之因鋼板表層形成Si濃化層而引起之酸洗性下降,導致表面缺陷增加或製造成本上升,故而欠佳。因此,Si含量係設為0.05~1.00%。關於下限,較佳為0.15%以上,更佳為0.20%以上。關於上限,較佳為0.60%以下,進而較佳為0.40%以下。 Si is an element which is condensed into an oxide film formed during welding to improve the corrosion resistance of the welded portion, and is also an element useful as a deoxidizing element in a steel making step. These effects are obtained by containing more than 0.05% of Si, and the greater the content, the greater these effects. However, if the Si content exceeds 1.00%, the increase in rolling load and significant scale formation in the hot rolling step, and the decrease in pickling properties caused by the formation of a Si-concentrated layer on the steel sheet surface during the annealing step, respectively. , Resulting in increased surface defects or manufacturing costs, so it is not good. Therefore, the Si content is set to 0.05 to 1.00%. The lower limit is preferably 0.15% or more, and more preferably 0.20% or more. The upper limit is preferably 0.60% or less, and further preferably 0.40% or less.

Mn:0.05~1.00% Mn: 0.05 ~ 1.00%

Mn具有提高鋼之強度之效果,又,亦具有作為脫氧劑之作用。為了獲得該等效果,必須含有0.05%以上之Mn。然而,若Mn含量超過1.00%,則會促進成為腐蝕起點之MnS之析出,而使耐蝕性下降。因此,Mn含量係設為0.05~1.00%。關於下限,較佳為0.10%以上,更佳為0.20%以上。關於上限,較佳為0.60%以下,進而較佳為0.40%以下。 Mn has the effect of increasing the strength of steel, and also has the function of a deoxidizer. In order to obtain these effects, it is necessary to contain Mn of 0.05% or more. However, if the Mn content exceeds 1.00%, the precipitation of MnS, which is the starting point of corrosion, is promoted, and the corrosion resistance is reduced. Therefore, the Mn content is set to 0.05 to 1.00%. The lower limit is preferably 0.10% or more, and more preferably 0.20% or more. The upper limit is preferably 0.60% or less, and further preferably 0.40% or less.

P:0.04%以下 P: 0.04% or less

P係鋼中不可避免地會含有之元素,由於是對耐蝕性及加工性有害之元素,因此較佳為儘可能減少。尤其是,若P含量超過0.04%,則會因固溶強化使加工性顯著下降。因此,P含量係設為0.04%以下。較佳為P含量為0.03%以下。再者,過度減少P含量需要過大之製造成本,因此若考慮製造成本,則P含量較佳為0.01%以上。 The elements inevitably contained in the P-based steel are preferably elements that are detrimental to corrosion resistance and workability. In particular, if the P content exceeds 0.04%, the workability is significantly reduced due to solid solution strengthening. Therefore, the P content is set to 0.04% or less. The P content is preferably 0.03% or less. Furthermore, excessively reducing the P content requires excessive manufacturing costs. Therefore, considering manufacturing costs, the P content is preferably 0.01% or more.

S:0.01%以下 S: 0.01% or less

S與P同樣地亦為鋼中不可避免地會含有之元素,由於是對耐蝕性及加工性有害之元素,因此較佳為儘可能減少。尤其是,若S含量超過0.01%,則耐蝕性顯著下降。因此,S含量係設為0.01%以下。較佳為S含量為0.008%以下。更佳為S含量為0.003%以下。再者,過度減少S含量需要過大之製造成本,因此若考慮製造成本,則S含量較佳為0.001%以上。 S and P are elements unavoidably contained in steel as well as P are elements that are harmful to corrosion resistance and workability. Therefore, it is preferable to reduce S as much as possible. In particular, if the S content exceeds 0.01%, the corrosion resistance significantly decreases. Therefore, the S content is set to 0.01% or less. The S content is preferably 0.008% or less. More preferably, the S content is 0.003% or less. Furthermore, excessively reducing the S content requires excessive manufacturing costs. Therefore, considering manufacturing costs, the S content is preferably 0.001% or more.

Al:0.001~0.100% Al: 0.001 ~ 0.100%

Al係有效之脫氧劑。進而,Al與氮之親和力強於Cr,因此於在焊接部中侵入有氮之情況時,具有使氮以Al氮化物之形式而非Cr氮化物之形式析出而抑制敏化之效果。該等效果係藉由含有0.001%以上之Al而獲得。然而,若含有Al超過0.100%,則焊接時之熔深性下降而焊接作業性下降,故而欠佳。因此,Al含量係設為0.001~0.100%之範圍。關於下限,較佳為0.010%以上,更佳為0.020%以上。關於上限,較佳為0.080%以下,進而較佳為0.060%以下。 Al is an effective deoxidizer. Furthermore, the affinity of Al and nitrogen is stronger than that of Cr. Therefore, when nitrogen is invaded in the welded portion, it has the effect of suppressing sensitization by precipitating nitrogen in the form of Al nitride instead of Cr nitride. These effects are obtained by containing 0.001% or more of Al. However, if the Al content is more than 0.100%, the penetration properties during welding are reduced and the welding workability is reduced, which is not satisfactory. Therefore, the Al content is set in the range of 0.001 to 0.100%. The lower limit is preferably 0.010% or more, and more preferably 0.020% or more. The upper limit is preferably 0.080% or less, and more preferably 0.060% or less.

Cr:10.0~19.0% Cr: 10.0 ~ 19.0%

Cr係對確保不鏽鋼之耐蝕性而言最重要之元素。若其含量未滿10.0%,則於汽車排放氣體環境下無法獲得充分之耐蝕性。另一方面,若含有Cr超過19.0%,則即便含有既定量之Ni,亦不會於熱軋步驟中之加熱時生成既定量之沃斯田鐵相,故而無法獲得充分之 聚落破壞效果,而無法獲得既定之低限應力強度因數。因此,Cr含量係設為10.0~19.0%之範圍。關於下限,較佳為10.5%以上,更佳為11.0%以上。關於上限,係較佳為16.5%以下、更佳為12.5%以下、進而較佳為11.5%以下之範圍。 Cr is the most important element for ensuring the corrosion resistance of stainless steel. If the content is less than 10.0%, sufficient corrosion resistance cannot be obtained in an automobile exhaust gas environment. On the other hand, if the Cr content exceeds 19.0%, even if a predetermined amount of Ni is contained, a predetermined amount of Vostian iron phases will not be generated during heating in the hot rolling step, so that sufficient settlement failure effect cannot be obtained, Unable to obtain the established low limit stress intensity factor. Therefore, the Cr content is set in the range of 10.0 to 19.0%. The lower limit is preferably 10.5% or more, and more preferably 11.0% or more. The upper limit is preferably in a range of 16.5% or less, more preferably 12.5% or less, and still more preferably 11.5% or less.

Ni:0.65~1.50% Ni: 0.65 ~ 1.50%

Ni係沃斯田鐵生成元素,具有使於熱軋步驟中之軋壓加工前之加熱時生成之沃斯田鐵量增加之效果。於本發明中,藉由將Cr及Ni之含量控制為既定量,而於熱軋步驟中之加熱時生成沃斯田鐵相。藉由該沃斯田鐵相之生成,鑄造時所形成之肥粒鐵相之聚落被破壞。又,於熱軋前之加熱溫度下,金屬組織成為肥粒鐵相+沃斯田鐵相之二相組織。於金屬組織成為肥粒鐵相+沃斯田鐵相之二相組織之情況時,於加熱前存在之肥粒鐵相與於加熱時生成之沃斯田鐵相之異相界面發揮作為結晶粒生長之障礙之功能,因此熱軋加工前之金屬組織微細化。其結果,熱軋後及後續步驟之熱軋板退火後之金屬組織微細化,而能夠表現出更優異之韌性改善效果。再者,根據鋼成分,存在於熱軋前之加熱溫度下金屬組織成為沃斯田鐵單相之情況,但於加熱溫度下之金屬組織成為沃斯田鐵單相組織之情況時,亦與上述同樣地獲得藉由沃斯田鐵相之生成產生之聚落破壞效果,並且沃斯田鐵相於熱軋前之鋼坯加熱溫度區域不易產生結晶粒之粗大化,因此熱軋前之金屬組織較基於習知技術之肥粒鐵系不鏽鋼變得微細,與上述同樣地獲得藉由結晶粒之微細化產生之韌性改善效果。該等效果係藉由含有0.65%以上之Ni而獲得。於Ni含量為0.65%以上之情況時,能夠藉由該等效果獲得35MPa.m1/2以上 之低限應力強度因數。另一方面,若Ni含量超過1.50%,則低限應力強度因數之改善效果飽和並且加工性下降。進而容易產生應力腐蝕破裂。因此,Ni含量係設為0.65~1.50%。關於下限,較佳為0.70%以上,更佳為0.75%以上。關於上限,較佳為1.00%以下,進而較佳為Ni含量為0.90%以下。 Ni is a Vosstian iron generating element, which has the effect of increasing the amount of Vosstian iron generated during heating before rolling in the hot rolling step. In the present invention, by controlling the contents of Cr and Ni to a predetermined amount, a Wastfield iron phase is generated during heating in the hot rolling step. Due to the generation of the Vostian iron phase, the aggregation of the fertile iron phase formed during casting is destroyed. In addition, at the heating temperature before hot rolling, the metal structure becomes a two-phase structure of a ferrous iron phase + a Wastfield iron phase. In the case where the metal structure becomes a two-phase structure of the ferrous iron phase + Vostian iron phase, the heterophase interface between the ferrous iron phase existing before heating and the Vostian iron phase generated during heating functions as crystal grain growth Because of its barrier function, the metal structure is refined before hot rolling. As a result, the metal structure of the hot-rolled sheet after hot rolling and subsequent steps is refined, and a more excellent toughness improving effect can be exhibited. Furthermore, depending on the steel composition, the metal structure may become a single phase of Vosstian iron at the heating temperature before hot rolling. The same effect as described above is obtained for the destruction of the settlement caused by the generation of the Vosstian iron phase, and the coarsening of crystal grains is not easy to occur in the heating temperature region of the slab before the hot-rolling iron phase. The ferritic iron-based stainless steel based on the conventional technology becomes fine, and the toughness improvement effect by miniaturizing the crystal grains is obtained in the same manner as described above. These effects are obtained by containing 0.65% or more of Ni. When the Ni content is 0.65% or more, 35 MPa can be obtained by these effects. Low limit stress intensity factor above m 1/2 . On the other hand, if the Ni content exceeds 1.50%, the effect of improving the low stress intensity factor is saturated and the workability is reduced. Furthermore, stress corrosion cracking is likely to occur. Therefore, the Ni content is set to 0.65 to 1.50%. The lower limit is preferably 0.70% or more, and more preferably 0.75% or more. The upper limit is preferably 1.00% or less, and more preferably the Ni content is 0.90% or less.

Ti:0.10~0.40% Ti: 0.10 ~ 0.40%

於本發明中,Ti係極為重要之元素。Ti具有如下效果:優先與C及N鍵結而抑制Cr碳氮化物之析出,從而使再結晶溫度下降,並且抑制起因於由Cr碳氮化物之析出引起之敏化的耐蝕性之下降。為了獲得該等效果,必須含有0.10%以上之Ti。然而,若Ti含量超過0.40%,則固溶Ti量過度增加,因此反而導致再結晶溫度上升,從而無法應用本發明之技術。又,含有Ti超過0.40%會於鑄造步驟中生成粗大之Ti碳氮化物,引起表面缺陷,故而於製造上亦欠佳。因此,Ti含量係設為0.10~0.40%。關於下限,較佳為0.15%以上,更佳為0.20%以上。進而更佳為0.25%以上。關於上限,較佳為0.35%以下,進而較佳為0.30%以下。再者,就焊接部耐蝕性之觀點而言,較佳為設為滿足式:Ti/(C+N)≧8(該式中之Ti、C及N係各元素之含量(質量%))之Ti含量。 In the present invention, Ti is an extremely important element. Ti has the effects of preferentially bonding with C and N to suppress the precipitation of Cr carbonitrides, thereby lowering the recrystallization temperature, and suppressing the decrease in corrosion resistance due to sensitization caused by the precipitation of Cr carbonitrides. In order to obtain these effects, Ti must be contained in an amount of 0.10% or more. However, if the Ti content exceeds 0.40%, the amount of solid solution Ti is excessively increased, and consequently the recrystallization temperature is increased, so that the technique of the present invention cannot be applied. In addition, if Ti is contained in excess of 0.40%, coarse Ti carbonitrides are formed in the casting step and surface defects are caused, which is also not good in manufacturing. Therefore, the Ti content is set to 0.10 to 0.40%. The lower limit is preferably 0.15% or more, and more preferably 0.20% or more. Furthermore, it is more preferably 0.25% or more. The upper limit is preferably 0.35% or less, and more preferably 0.30% or less. Furthermore, from the viewpoint of corrosion resistance of the welded portion, it is preferable to satisfy the formula: Ti / (C + N) ≧ 8 (the content (mass%) of each element of Ti, C, and N in the formula) Of Ti content.

N:0.001~0.020% N: 0.001 ~ 0.020%

若N含量超過0.020%,則加工性之下降及焊接部之耐蝕性之下降變得顯著。就耐蝕性之觀點而言,N含量越低則越佳,但使N含量減少至未滿0.001%需要長時間之精煉,會導致製造成本之上 升及生產性之下降,故而欠佳。因此,N含量係設為0.001~0.020%之範圍。關於下限,較佳為0.005%以上,更佳為0.007%以上。關於上限,較佳為0.015%以下,進而較佳為0.012%以下。 When the N content exceeds 0.020%, a decrease in workability and a decrease in corrosion resistance of the welded portion become significant. From the viewpoint of corrosion resistance, the lower the N content is, the better it is. However, reducing the N content to less than 0.001% requires long-term refining, which leads to an increase in manufacturing costs and a decrease in productivity, which is not good. Therefore, the N content is set in the range of 0.001 to 0.020%. The lower limit is preferably 0.005% or more, and more preferably 0.007% or more. The upper limit is preferably 0.015% or less, and more preferably 0.012% or less.

本發明係以含有上述必需成分且剩餘部分包含Fe及不可避免之雜質為特徵的肥粒鐵系不鏽鋼。進而,可視需要於下述範圍內含有選自Cu、Mo、W及Co中之1種或2種以上或/進而含有選自V、Nb、Zr、REM、B、Mg及Ca中之1種或2種以上。再者,於下限值處於下述範圍內之情況時,即便未滿其下限值地含有下述元素,亦無損本發明之效果,因此於未滿下限值地包含下述元素之情況時,該元素係設為不可避免之雜質。 The present invention is a ferritic iron-based stainless steel characterized by containing the above-mentioned essential components and the remainder containing Fe and unavoidable impurities. Further, if necessary, one or two or more selected from Cu, Mo, W, and Co or / and one or more selected from V, Nb, Zr, REM, B, Mg, and Ca may be contained in the following range. Or 2 or more. In addition, when the lower limit value is within the following range, the effect of the present invention is not impaired even if the following elements are included below the lower limit value. Therefore, the following elements are included below the lower limit value. In this case, the element is an unavoidable impurity.

Cu:0.01~1.00% Cu: 0.01 ~ 1.00%

Cu係對提昇水溶液中或附著有弱酸性之水滴之情況時之母材及焊接部之耐蝕性尤其有效之元素。該效果係藉由含有0.01%以上之Cu而獲得,該效果係Cu含量越多則越高。然而,若含有Cu超過1.00%,則存在熱加工性下降而導致表面缺陷之情況。進而亦存在退火後之脫鏽皮變得困難之情況。因此,於含有Cu之情況時,Cu含量較佳為設為0.01~1.00%之範圍。關於下限,更佳為0.10%以上,進而較佳為0.30%以上。關於上限,更佳為0.60%以下,進而較佳為0.45%以下。 Cu is an element that is particularly effective in improving the corrosion resistance of the base material and the welded part when a weakly acidic water droplet is attached to the aqueous solution. This effect is obtained by containing 0.01% or more of Cu, and the effect is that the higher the Cu content, the higher. However, when Cu is contained in excess of 1.00%, hot workability may be reduced and surface defects may be caused. Furthermore, it may become difficult to remove the scale after annealing. Therefore, when Cu is contained, the Cu content is preferably in the range of 0.01 to 1.00%. The lower limit is more preferably 0.10% or more, and still more preferably 0.30% or more. The upper limit is more preferably 0.60% or less, and still more preferably 0.45% or less.

Mo:0.01~2.00% Mo: 0.01 ~ 2.00%

Mo係顯著提昇不鏽鋼之耐蝕性之元素。該效果係藉由含有0.01%以上之Mo而獲得,該效果係含量越多則越提昇。然而,若 Mo含量超過2.00%,則存在熱軋時之軋壓負載變大而製造性下降或產生鋼板強度之過度上升之情況。又,Mo為較為昂貴之元素,因此大量含有Mo會使製造成本增大。因此,於含有Mo之情況時,Mo含量較佳為設為0.01~2.00%。關於下限,更佳為0.10%以上,進而較佳為0.30%以上。關於上限,更佳為1.40%以下,進而較佳為0.90%以下。 Mo is an element that significantly improves the corrosion resistance of stainless steel. This effect is obtained by containing 0.01% or more of Mo, and the more the effect content is, the higher it is. However, if the Mo content exceeds 2.00%, the rolling load at the time of hot rolling may be increased, the manufacturability may be lowered, or the strength of the steel sheet may be excessively increased. In addition, Mo is a relatively expensive element, and therefore, containing a large amount of Mo increases manufacturing costs. Therefore, when Mo is contained, the Mo content is preferably set to 0.01 to 2.00%. The lower limit is more preferably 0.10% or more, and still more preferably 0.30% or more. The upper limit is more preferably 1.40% or less, and still more preferably 0.90% or less.

W:0.01~0.20% W: 0.01 ~ 0.20%

W與Mo同樣地具有提昇耐蝕性之效果。該效果係藉由含有0.01%以上之W而獲得。然而,若含有W超過0.20%,則存在強度上升而導致因軋壓負重之增大等引起之製造性下降之情況。因此,於含有W之情況時,W含量較佳為設為0.01~0.20%之範圍。關於下限,更佳為0.05%以上。關於上限,更佳為0.15%以下。 W has the same effect as Mo in improving corrosion resistance. This effect is obtained by containing W of 0.01% or more. However, if W is contained in an amount exceeding 0.20%, the strength may be increased, and the manufacturability may be reduced due to an increase in rolling load. Therefore, when W is contained, the W content is preferably set in the range of 0.01 to 0.20%. The lower limit is more preferably 0.05% or more. The upper limit is more preferably 0.15% or less.

Co:0.01~0.20% Co: 0.01 ~ 0.20%

Co係提昇韌性之元素。該效果係藉由含有0.01%以上之Co而獲得。另一方面,若Co含量超過0.20%,則存在加工性下降之情況。因此,於含有Co之情況時,Co含量較佳為設為0.01~0.20%之範圍。 Co is an element that improves toughness. This effect is obtained by containing Co in an amount of 0.01% or more. On the other hand, if the Co content exceeds 0.20%, the processability may be reduced. Therefore, when Co is contained, the Co content is preferably set in the range of 0.01 to 0.20%.

V:0.01~0.20% V: 0.01 ~ 0.20%

V與C及N形成碳氮化物,抑制Cr碳氮化物之析出而提昇焊接部之耐蝕性。該效果係藉由使V含量為0.01%以上而獲得。另一方面,若V含量超過0.20%,則存在加工性及韌性顯著下降之情況。 因此,V含量較佳為設為0.01~0.20%。關於下限,更佳為0.02%以上。關於上限,更佳為0.10%以下。 V forms carbonitrides with C and N, suppresses the precipitation of Cr carbonitrides, and improves the corrosion resistance of the welded portion. This effect is obtained by setting the V content to 0.01% or more. On the other hand, when the V content exceeds 0.20%, the workability and toughness may be significantly reduced. Therefore, the V content is preferably set to 0.01 to 0.20%. The lower limit is more preferably 0.02% or more. The upper limit is more preferably 0.10% or less.

Nb:0.01~0.10% Nb: 0.01 ~ 0.10%

Nb具有藉由使結晶粒微細化並且固溶於母相中而提昇鋼板之韌性之效果。該等效果係藉由含有0.01%以上之Nb而獲得。另一方面,Nb亦具有使再結晶溫度上升之效果,若Nb含量超過0.10%,則存在藉由熱軋板退火產生充分之再結晶所需之退火溫度變得過高,而於退火中產生如結晶粒徑最大成為300μm以上般之再結晶粒之顯著粗大化,從而無法獲得既定之低限應力強度因數之情況。因此,於含有Nb之情況時,Nb含量較佳為設為0.01~0.10%之範圍。關於下限,更佳為0.02%以上。關於上限,更佳為0.08%以下。 Nb has the effect of increasing the toughness of the steel sheet by making the crystal grains finer and dissolving in the mother phase. These effects are obtained by containing Nb of 0.01% or more. On the other hand, Nb also has the effect of increasing the recrystallization temperature. If the Nb content exceeds 0.10%, the annealing temperature required to produce sufficient recrystallization by hot-rolled sheet annealing will become too high, and it will occur during annealing. When the crystal grain size is at most 300 μm or more, the recrystallized grains are significantly coarsened, so that a predetermined low limit stress intensity factor cannot be obtained. Therefore, when Nb is contained, the Nb content is preferably set in the range of 0.01 to 0.10%. The lower limit is more preferably 0.02% or more. The upper limit is more preferably 0.08% or less.

Zr:0.01~0.20% Zr: 0.01 ~ 0.20%

V與C及N形成碳氮化物,抑制Cr碳氮化物之析出而提昇焊接部之耐蝕性。該效果係藉由含有0.01%以上之Zr而獲得。另一方面,若含有Zr超過0.20%,則存在加工性顯著下降之情況。因此,於含有Zr之情況時,Zr含量較佳為設為0.01~0.20%之範圍。關於下限,更佳為0.03%以上。關於上限,更佳為0.10%以下。 V forms carbonitrides with C and N, suppresses the precipitation of Cr carbonitrides, and improves the corrosion resistance of the welded portion. This effect is obtained by containing Zr of 0.01% or more. On the other hand, if the content of Zr exceeds 0.20%, the workability may be significantly reduced. Therefore, when Zr is contained, the Zr content is preferably in the range of 0.01 to 0.20%. The lower limit is more preferably 0.03% or more. The upper limit is more preferably 0.10% or less.

REM:0.001~0.100% REM: 0.001 ~ 0.100%

稀土類金屬(REM,Rare Earth Metals)具有提昇耐氧化性之效果,抑制焊接部之氧化皮膜(焊接回火色)形成,抑制氧化皮膜正下方之Cr缺失區域之形成,從而提昇焊接部之耐蝕性。該效果係藉 由含有0.001%以上之REM而獲得。另一方面,若含有REM超過0.100%,則存在使冷軋退火時之酸洗性等製造性下降之情況。因此,於含有REM之情況時,REM含量較佳為設為0.001~0.100%之範圍。關於下限,更佳為0.005%以上。關於上限,更佳為0.050%以下。 Rare earth metals (REM, Rare Earth Metals) have the effect of improving the oxidation resistance, inhibiting the formation of oxide film (weld tempering color) in the welded part, inhibiting the formation of Cr-missing areas directly under the oxide film, thereby improving the corrosion resistance of the welded part Sex. This effect is obtained by containing REM of 0.001% or more. On the other hand, when the REM content exceeds 0.100%, the manufacturability such as pickling properties during cold rolling annealing may be reduced. Therefore, when REM is contained, the REM content is preferably set to the range of 0.001 to 0.100%. The lower limit is more preferably 0.005% or more. The upper limit is more preferably 0.050% or less.

B:0.0002~0.0025% B: 0.0002 ~ 0.0025%

B係有效改善深拉拔成形後之耐二次加工脆性之元素。該效果係藉由將B之含量設為0.0002%以上而獲得。另一方面,若含有B超過0.0025%,則存在加工性及韌性下降之情況。因此,於含有B之情況時,B含量較佳為設為0.0002~0.0025%之範圍。關於下限,更佳為0.0003%以上。關於上限,更佳為0.0006%以下。 B is an element that effectively improves the secondary processing embrittlement resistance after deep drawing. This effect is obtained by setting the content of B to 0.0002% or more. On the other hand, if the content of B exceeds 0.0025%, workability and toughness may be reduced. Therefore, when B is contained, the B content is preferably set to the range of 0.0002 to 0.0025%. The lower limit is more preferably 0.0003% or more. The upper limit is more preferably 0.0006% or less.

Mg:0.0005~0.0030% Mg: 0.0005 ~ 0.0030%

Mg係提昇鋼坯之等軸晶率而對提昇加工性或韌性有效之元素。進而,於如本發明般含有Ti之鋼中,若Ti碳氮化物粗大化,則韌性下降,但Mg亦具有抑制Ti碳氮化物之粗大化之效果。該等效果係藉由含有0.0005%以上之Mg而獲得。另一方面,若Mg含量超過0.0030%,則存在使鋼之表面性狀變差之情況。因此,於含有Mg之情況時,Mg含量較佳為設為0.0005~0.0030%之範圍。關於下限,更佳為0.0010%以上。關於上限,更佳為0.0020%以上。 Mg is an element effective for increasing the equiaxed crystal ratio of the slab and improving the workability or toughness. Furthermore, in a steel containing Ti as in the present invention, if the Ti carbonitride is coarsened, the toughness is reduced, but Mg also has the effect of suppressing the coarsening of the Ti carbonitride. These effects are obtained by containing Mg of 0.0005% or more. On the other hand, if the Mg content exceeds 0.0030%, the surface properties of the steel may be deteriorated. Therefore, when Mg is contained, the content of Mg is preferably in the range of 0.0005 to 0.0030%. The lower limit is more preferably 0.0010% or more. The upper limit is more preferably 0.0020% or more.

Ca:0.0003~0.0030% Ca: 0.0003 ~ 0.0030%

Ca係有效防止容易於連續鑄造時產生之由Ti系中介物之晶化 所引起之噴嘴之堵塞的成分。該效果係藉由含有0.0003%以上之Ca而獲得。然而,若含有Ca超過0.0030%,則存在因CaS之生成使耐蝕性下降之情況。因此,於含有Ca之情況時,Ca含量較佳為設為0.0003~0.0030%之範圍。關於下限,更佳為0.0005%以上,進而較佳為0.0006%以上。關於上限,更佳為0.0015%以下,進而較佳為0.0010%以下。 Ca is an effective component to prevent nozzle clogging caused by crystallization of Ti-based intermediaries, which is easily generated during continuous casting. This effect is obtained by containing Ca of 0.0003% or more. However, if the Ca content exceeds 0.0030%, the corrosion resistance may decrease due to the generation of CaS. Therefore, when Ca is contained, the Ca content is preferably in the range of 0.0003 to 0.0030%. The lower limit is more preferably 0.0005% or more, and still more preferably 0.0006% or more. The upper limit is more preferably 0.0015% or less, and still more preferably 0.0010% or less.

其次,對本發明之肥粒鐵系不鏽鋼熱軋退火鋼板之製造方法進行說明。 Next, the manufacturing method of the ferritic iron-based stainless steel hot-rolled annealed steel sheet of the present invention will be described.

本發明之肥粒鐵系不鏽鋼熱軋退火鋼板係藉由使用具有上述成分組成之鋼坯,於包含粗軋及3道以上之精軋之熱軋中,於溫度為800~1100℃且最終3道之累積軋縮率為25%以上之條件下進行精軋之最終3道之軋壓,而獲得熱軋鋼板,進而以600~1100℃對該熱軋鋼板進行熱軋板退火而獲得。 The ferritic iron-based stainless steel hot-rolled and annealed steel sheet of the present invention uses a slab having the above-mentioned composition in a hot rolling process including rough rolling and finishing rolling of 3 or more passes at a temperature of 800 to 1100 ° C and finally 3 passes. The final three rolling passes of finishing rolling are performed under the condition that the cumulative rolling reduction rate is 25% or more to obtain a hot-rolled steel sheet, and the hot-rolled steel sheet is annealed at 600 to 1100 ° C.

首先,利用轉爐、電爐及真空熔解爐等公知之方法熔製包含上述成分組成之鋼液,藉由連續鑄造法或造坯-開坯法製成鋼素材(鋼坯)。 First, a known method such as a converter, an electric furnace, and a vacuum melting furnace is used to melt a molten steel containing the above-mentioned composition, and a steel material (slab) is produced by a continuous casting method or a billet-opening method.

將該鋼坯以1050~1250℃加熱1~24小時或不加熱而以鑄造原樣直接供至熱軋。於本發明中,粗軋並無特別限定,但於在精熱軋前預先有效地破壞鑄造組織之情況時,會對其後之精熱軋中之結晶粒之微細化產生良好的效果,因此較佳為將粗軋中之累積軋縮率設為65%以上。其後,藉由精熱軋進行軋壓直至成為既定板厚,將精軋之最終3道之軋壓設為800~1100℃之溫度範圍並將累積軋縮率設為25%以上而進行。 The slab is heated at 1050 to 1250 ° C for 1 to 24 hours or is directly supplied to the hot rolling as it is without being heated. In the present invention, rough rolling is not particularly limited, but when the cast structure is effectively destroyed in advance before the finish hot rolling, it will have a good effect on the miniaturization of crystal grains in the subsequent finish hot rolling. Therefore, The cumulative rolling reduction during rough rolling is preferably 65% or more. Thereafter, rolling is performed by finishing hot rolling until it reaches a predetermined thickness, and rolling in the last three passes of finishing rolling is set to a temperature range of 800 to 1100 ° C, and the cumulative rolling reduction is set to 25% or more.

最終3道之軋壓溫度範圍:800~1100℃ The rolling temperature range of the final 3 passes: 800 ~ 1100 ℃

最終3道之累積軋縮率:25%以上 Cumulative rolling reduction in the last 3 passes: more than 25%

於精軋前之粗軋中,粗大之鑄造組織被破壞,但該組織之結晶粒顯著粗大。為了於熱軋板退火後獲得既定之低限應力強度因數,必須藉由適當控制最終3道之軋壓之溫度及累積軋縮率而抑制軋壓中之應變之恢復,並且尤其是對板厚中央部有效地賦予軋壓應變。 During rough rolling before finishing rolling, the coarse cast structure was destroyed, but the crystal grains of the structure were significantly coarse. In order to obtain the predetermined low-limit stress intensity factor after hot-rolled sheet annealing, it is necessary to suppress the recovery of the strain in the rolling by properly controlling the rolling temperature and the cumulative rolling reduction rate of the final 3 passes, especially for the plate thickness. The central portion effectively imparts rolling strain.

必須對板厚中央部有效地賦予軋壓應變之理由在於如下。軋壓加工係藉由使鋼板發生剪切變形而使鋼板之板厚變薄的加工。軋壓加工中之剪切應變(以下記作軋壓應變)之量係自表層朝向板厚中央變小。因此,於軋縮率較小之情況時,對鋼板表層附近賦予較大之軋壓應變,另一方面,對板厚中央部賦予之軋壓應變之量變小。軋壓應變成為後續步驟即熱軋板退火中之再結晶位置。然而,於對板厚中央部賦予之軋壓應變量較小之情況時,熱軋板退火時之板厚中央部之再結晶變得不充分,熱軋板退火鋼板之金屬組織於板厚方向變得不均勻,而無法獲得既定之低限應力強度因數。因此,為了對板厚中央部有效地賦予軋壓應變,必須以特定以上之軋縮率進行軋壓且進行至產生軋壓應變之恢復為止。 The reason why it is necessary to effectively impart rolling strain to the center portion of the plate thickness is as follows. The rolling process is a process of reducing the thickness of the steel sheet by shearing the steel sheet. The amount of the shear strain (hereinafter referred to as rolling strain) in the rolling process becomes smaller from the surface layer toward the center of the plate thickness. Therefore, when the reduction ratio is small, a large rolling strain is given to the vicinity of the surface layer of the steel sheet, and on the other hand, the amount of the rolling strain given to the center portion of the plate thickness is small. The rolling strain becomes the recrystallization position in the subsequent step, that is, the annealing of the hot rolled sheet. However, when the rolling strain applied to the center portion of the sheet thickness is small, the recrystallization of the center portion of the sheet thickness during the annealing of the hot-rolled sheet becomes insufficient, and the metal structure of the annealed sheet of the hot-rolled sheet is in the thickness direction. It becomes non-uniform, and the established low limit stress intensity factor cannot be obtained. Therefore, in order to effectively impart a rolling strain to the center portion of the plate thickness, it is necessary to perform rolling at a specific reduction rate or more until the recovery of the rolling strain occurs.

為了於後續步驟即熱軋板退火中導入充分之再結晶位置以獲得既定之金屬組織,必須將最終3道之軋壓溫度設為800~1100℃之範圍,且將最終3道之累積軋縮率(=100-(最終板厚/最終3道之軋壓開始前之板厚)×100[%])設為25%以上,防止藉由最終3道賦予之軋壓應變因恢復而消除,並且對板厚中央部有效地賦予軋壓應變。 In order to introduce a sufficient recrystallization position in the subsequent step, ie, hot-rolled sheet annealing, to obtain a predetermined metal structure, the rolling temperature of the final 3 passes must be set to a range of 800 to 1100 ° C, and the cumulative rolling of the final 3 passes must be rolled. The ratio (= 100- (final sheet thickness / thickness before the rolling of the last 3 passes) × 100 [%]) is set to 25% or more to prevent the rolling strain imparted by the final 3 passes from being restored due to recovery. In addition, a rolling strain is effectively given to the center of the plate thickness.

若最終3道之累積軋縮率未滿25%,則無法有效地對 板厚中央部賦予軋壓應變,因此會導致於後續步驟之熱軋板退火中聚落殘留,而無法獲得既定之低限應力強度因數。因此,將最終3道之累積軋縮率設為25%以上。較佳為累積軋縮率為30%以上。進而較佳為累積軋縮率為35%以上。再者,累積軋縮率之上限並無特別限定,但若過度增大累積軋縮率,則存在軋壓負載上升而製造性下降並且於軋壓後產生表面粗糙之情況,因此較佳為設為60%以下。 If the cumulative rolling reduction rate in the last 3 passes is less than 25%, rolling stress cannot be effectively imparted to the central part of the sheet thickness, so it will cause residual settlement in the hot-rolled sheet annealing in the subsequent steps, and the established lower limit cannot be obtained. Stress intensity factor. Therefore, the cumulative rolling reduction of the last three passes is set to 25% or more. The cumulative rolling reduction is preferably 30% or more. The cumulative rolling reduction is more preferably 35% or more. In addition, the upper limit of the cumulative rolling reduction rate is not particularly limited, but if the cumulative rolling reduction rate is excessively increased, the rolling load may increase, the manufacturability may decrease, and the surface may be roughened after rolling. It is 60% or less.

於將最終3道之軋壓溫度設為未滿800℃之情況時,伴隨鋼板溫度之下降,軋壓負重顯著上升,因此於製造上欠佳。又,存在因低溫下之軋壓而產生鋼板表面之粗糙而使表面品質下降之情況。另一方面,若最終3道之軋壓溫度超過1100℃,則會產生藉由軋壓賦予之應變之恢復,而後續步驟之熱軋板退火後之再結晶位置不足,因此會導致於熱軋板退火後聚落殘留,而無法獲得既定之低限應力強度因數。因此,最終3道之軋壓溫度係設為800~1100℃之範圍。關於下限,較佳為850℃以上。關於上限,較佳為設為1050℃以下,更佳為設為1000℃以下。又,所謂最終3道之軋壓溫度,最終道係指軋壓結束溫度,此外係指軋壓開始溫度。 When the rolling temperature of the last 3 passes is set to less than 800 ° C, the rolling load increases significantly with the decrease in the temperature of the steel sheet, and therefore it is not good in manufacturing. In addition, there is a case where the surface of the steel sheet is roughened by rolling at a low temperature, and the surface quality may be deteriorated. On the other hand, if the rolling temperature of the final 3 passes exceeds 1100 ° C, recovery of the strain imparted by the rolling will occur, and the recrystallization position after the annealing of the hot-rolled sheet in the subsequent steps will be insufficient, which will result in hot rolling. After the sheet was annealed, the settlement remained, and the predetermined low limit stress intensity factor could not be obtained. Therefore, the rolling temperature of the last three passes is set to a range of 800 to 1100 ° C. The lower limit is preferably 850 ° C or higher. The upper limit is preferably 1050 ° C or lower, and more preferably 1000 ° C or lower. In addition, the rolling temperature of the last 3 passes refers to the rolling end temperature and the rolling start temperature.

再者,為了防止於最終3道中之特定道中施加過度之軋壓負載,較佳為將最終3道中之第1道之軋壓溫度範圍設為950~1100℃,將該第1道之後進行之第2道之軋壓溫度範圍設為925~1075℃,將該第2道之後進行之第3道之軋壓溫度範圍設為875~1050℃。 Furthermore, in order to prevent an excessive rolling load from being applied to a specific one of the last three passes, it is preferable to set the rolling temperature range of the first one of the last three passes to 950 to 1100 ° C, and to perform the process after the first pass. The rolling temperature range of the second pass is set to 925 to 1075 ° C, and the rolling temperature range of the third pass performed after the second pass is set to 875 to 1050 ° C.

又,本發明之肥粒鐵系不鏽鋼熱軋退火鋼板之製造方法之特徵在於:於包含3道以上之精熱軋之最終3道中控制溫度範 圍,在此基礎上,施加較大之軋縮。若遍及最終之4道以上而進行施加較大之軋縮之軋壓,則即便為相同之累積軋縮率,亦因軋縮率分散至各道,故對板厚中央之應變賦予變得不充分,並且各道間之累積搬送時間增加,因此會助長於各道間進行搬送期間之恢復,而使應變賦予之效果下降。又,若將精軋之軋壓溫度及累積軋縮率之控制設為最終之2道以下,則存在因以2道進行累積軋縮率25%以上之大軋縮,故軋壓負載顯著上升而使製造性下降之情況,故而欠佳。因此,於本發明之肥粒鐵系不鏽鋼熱軋鋼板之製造方法中,控制精軋之最終3道之軋壓溫度及累積軋縮率。 In addition, the method for manufacturing a ferritic-iron-based stainless steel hot-rolled annealed steel sheet according to the present invention is characterized in that a temperature range is controlled in the final three passes including three or more finish hot rolling, and on this basis, a larger rolling reduction is applied. If a larger rolling reduction is performed throughout the final 4 or more passes, even if it is the same cumulative rolling reduction rate, the rolling reduction rate is distributed to each pass, so the strain impartment to the center of the plate thickness becomes ineffective It is sufficient, and the cumulative transfer time between the lanes is increased, so it will facilitate recovery during the transfer between lanes, and reduce the effect of strain imparting. In addition, if the control of the rolling temperature and the cumulative rolling reduction rate of finishing rolling are set to two or less in the end, there will be a large rolling with cumulative rolling reduction of 25% or more in two passes, so the rolling load will increase significantly. The situation that the manufacturability is reduced is not good. Therefore, in the manufacturing method of the ferritic iron-based stainless steel hot-rolled steel sheet of the present invention, the rolling temperature and the cumulative rolling reduction rate of the last three passes of the finish rolling are controlled.

再者,於本發明之肥粒鐵系不鏽鋼熱軋鋼板之製造方法中,關鍵的是控制最終3道之軋壓溫度及累積軋縮率,只要為3道以上之精軋,則可進行任意道之精軋。但是,若最大道數多於15道,則存在導致製造性下降或製造成本增加之情況,例如容易因與軋壓輥之接觸次數之增加而產生鋼板溫度之下降,為了將鋼板溫度維持於既定溫度範圍內而必需來自外部之加熱,因此最大道數較佳為設為15道以下。更佳為最大道數為10道以下。 Furthermore, in the manufacturing method of the ferritic-iron-based stainless steel hot-rolled steel sheet of the present invention, it is critical to control the rolling temperature and the cumulative rolling reduction rate of the final 3 passes, as long as the finishing rolling is more than 3 passes, it can be performed arbitrarily. The rolling of the Tao. However, if the maximum number of passes is more than 15, there may be cases in which the manufacturability is reduced or the manufacturing cost is increased. For example, the temperature of the steel sheet is likely to decrease due to the increase in the number of contact with the rolling rolls. It is necessary to apply external heating within a temperature range, so the maximum number of channels is preferably 15 or less. More preferably, the maximum number of channels is 10 or less.

精熱軋後進行鋼板之冷卻,繼而進行鋼板之捲取處理而製成熱軋鋼帶。於本發明中,捲取溫度並無特別限定,於將捲取溫度設為超過450~未滿500℃之情況時,存在產生起因於475℃脆化之脆化之情況。因此,捲取溫度較佳為設為450℃以下或500℃以上。 After finishing hot rolling, the steel sheet is cooled, and then the steel sheet is coiled to produce a hot-rolled steel strip. In the present invention, the coiling temperature is not particularly limited. When the coiling temperature is set to exceed 450 to 500 ° C, embrittlement may occur due to embrittlement at 475 ° C. Therefore, the winding temperature is preferably 450 ° C or lower or 500 ° C or higher.

熱軋板退火溫度:600~1100℃ Hot rolled sheet annealing temperature: 600 ~ 1100 ℃

於本發明中,於上述熱軋步驟結束後進行熱軋板退火。於熱軋 板退火中,使熱軋步驟中所形成之軋壓加工組織再結晶。於本發明中,於熱軋步驟中有效地賦予軋壓應變,使再結晶位置增加,藉此促進熱軋板退火中之聚落之破壞。為了獲得該效果,必須於600~1100℃之範圍內進行熱軋板退火。若退火溫度未滿600℃,則再結晶變得不充分,而無法獲得既定之低限應力強度因數。另一方面,若退火溫度超過1100℃,則再結晶粒會產生如結晶粒徑最大成為300μm以上般之顯著粗大化,而無法獲得既定之低限應力強度因數。因此,熱軋板退火溫度係設為600~1100℃之範圍。關於下限,較佳為650℃以上。更佳為700℃以上。關於上限,較佳為1050℃以下,進而較佳為900℃以下。再者,熱軋板退火之保持時間及方法並無特別限定,可藉由箱式退火(分批退火)、連續退火中之任一者實施。 In the present invention, the hot-rolled sheet annealing is performed after the hot-rolling step is completed. In the hot-rolled sheet annealing, the rolled working structure formed in the hot-rolling step is recrystallized. In the present invention, the rolling strain is effectively imparted in the hot rolling step to increase the recrystallization position, thereby promoting the destruction of the settlement during the annealing of the hot rolled sheet. In order to obtain this effect, it is necessary to perform hot-rolled sheet annealing in a range of 600 to 1100 ° C. If the annealing temperature is less than 600 ° C, recrystallization becomes insufficient, and a predetermined low limit stress intensity factor cannot be obtained. On the other hand, if the annealing temperature exceeds 1100 ° C., the recrystallized grains will be significantly coarsened as the maximum grain size becomes 300 μm or more, and a predetermined low limit stress intensity factor cannot be obtained. Therefore, the hot-rolled sheet annealing temperature is set to a range of 600 to 1100 ° C. The lower limit is preferably 650 ° C or higher. It is more preferably 700 ° C or higher. The upper limit is preferably 1050 ° C or lower, and more preferably 900 ° C or lower. In addition, the holding time and method of the hot-rolled sheet annealing are not particularly limited, and can be performed by any of box annealing (batch annealing) and continuous annealing.

亦可視需要對所獲得之熱軋退火鋼板進行利用噴丸或酸洗之脫鏽皮處理。進而,為了提昇表面性狀,亦可實施研削或研磨等。又,本發明所提供之熱軋退火鋼板亦可於之後進行冷軋及冷軋板退火。 If necessary, the obtained hot-rolled annealed steel sheet may be subjected to descaling treatment by shot blasting or pickling. Furthermore, in order to improve surface properties, grinding, polishing, etc. may be performed. In addition, the hot-rolled annealed steel sheet provided by the present invention may be cold-rolled and cold-rolled sheet-annealed afterwards.

[實施例]     [Example]    

以下,藉由實施例對本發明進行詳細說明。 Hereinafter, the present invention will be described in detail through examples.

藉由容量150 ton之轉爐及強攪拌-真空吹氧脫碳處理(SS-VOD)之精煉熔製具有表1所示之化學組成之不鏽鋼鋼液,藉由連續鑄造製成寬度1000mm、厚度200mm之鋼坯。除No.36以外,於將該鋼坯以1150℃加熱1hr後,進行使用3段支架之反向粗軋作為熱軋,而製成板厚約40mm之鋼板,繼而以表2中記載之條件進行包含7道之精軋之最終3道(第5道、第6道、第7道),而製 成熱軋鋼板。No.36係將該鋼坯以1300℃加熱1hr後供至熱軋。針對所獲得之熱軋鋼板,同樣地以表2中記載之條件進行利用箱式退火之熱軋板退火,而獲得熱軋退火板。再者,第7道結束板厚為熱軋鋼板之板厚。對所獲得之熱軋退火鋼板進行以下之評價。 The stainless steel molten steel with the chemical composition shown in Table 1 was melted and melted by a 150 ton converter and a strong agitation-vacuum oxygen decarburization treatment (SS-VOD). Of billets. Except for No. 36, after heating the slab at 1150 ° C for 1 hour, reverse rough rolling using a three-segment stand as hot rolling was performed to produce a steel plate with a thickness of about 40 mm, followed by the conditions described in Table 2. The final 3 passes (the 5th pass, the 6th pass, and the 7th pass) including 7 finish rolling are made into a hot-rolled steel sheet. No. 36 series was heated at 1300 ° C for 1 hour and then supplied to hot rolling. About the obtained hot-rolled steel sheet, the hot-rolled sheet annealing using box annealing was performed under the conditions described in Table 2 to obtain a hot-rolled annealed sheet. In addition, the thickness at the end of the seventh pass is the thickness of the hot-rolled steel sheet. The obtained hot-rolled annealed steel sheet was evaluated as follows.

(1)低限應力強度因數KIC之評價 (1) Evaluation of low limit stress intensity factor K IC

以疲勞預裂成為軋壓直角方向且應力軸成為軋壓平行方向之方式自板寬中央部採取依據ASTM E399之緊湊拉伸(CT,compact tension)試片。針對該試片,依據ASTM E399求出低限應力強度因數KIC。將低限應力強度因數為35MPa.m1/2以上設為合格,將未滿35MPa.m1/2設為不合格。 A compact tension (CT) compact test piece according to ASTM E399 was taken from the center of the plate width in such a manner that the fatigue pre-cracking became the rolling right angle direction and the stress axis became the rolling parallel direction. For this test piece, a low limit stress intensity factor K IC was obtained in accordance with ASTM E399. Set the lower limit stress intensity factor to 35MPa. If m 1/2 or more is set to pass, it will be less than 35MPa. m 1/2 is regarded as a failure.

(2)耐蝕性之評價 (2) Evaluation of corrosion resistance

自熱軋退火鋼板採取60×100mm之試片,利用#600砂紙對要評價之面之表面進行研磨整飾後,為了排除來自端面部及背面之影響,將端面部及背面密封,而製作試片,並將試片供至JIS H 8502中規定之鹽水噴霧循環試驗。鹽水噴霧循環試驗係將鹽水噴霧(5質量%NaCl、35℃、噴霧2hr)→乾燥(60℃、4hr、相對濕度40%)→濕潤(50℃、2hr、相對濕度≧95%)作為1個循環而進行5個循環。對將鹽水噴霧循環試驗實施5個循環後之要評價之面之試片表面進行照相攝影,藉由圖像分析測定試片表面之生鏽面積,根據與試片總面積之比率算出生鏽率((試片中之生鏽面積/試片總面積)×100[%])。將生鏽率10%以下設為耐蝕性特別優異而合格(◎),將超過10%且為25%以下設為合格(○),將超過25%設為不合格(×)。 A test piece of 60 × 100 mm was taken from the hot-rolled annealed steel sheet, and the surface of the surface to be evaluated was ground and finished with # 600 sandpaper. In order to eliminate the influence from the end surface and the back surface, the end surface and the back surface were sealed to produce a test The test piece was subjected to a salt water spray cycle test specified in JIS H 8502. The salt water spray cycle test system uses salt water spray (5 mass% NaCl, 35 ° C, 2hr spray) → dry (60 ° C, 4hr, relative humidity 40%) → humid (50 ° C, 2hr, relative humidity ≧ 95%) as one 5 cycles were performed. The surface of the test piece on the side to be evaluated after 5 cycles of the salt water spray cycle test was photographed, and the rust area on the surface of the test piece was measured by image analysis. The rust rate was calculated based on the ratio to the total area of the test piece. ((Rust area in test piece / total area of test piece) x 100 [%]). A rust rate of 10% or less is considered to be particularly excellent and has a good corrosion resistance (◎), a rust rate of more than 10% to 25% or less is considered to be a pass (○), and more than 25% is considered to be a fail (×).

將試驗結果與熱軋及熱軋板退火條件一起表示於表2。 The test results are shown in Table 2 together with the hot-rolled and hot-rolled sheet annealing conditions.

鋼成分、熱軋條件及熱軋板退火條件滿足本發明之範圍之表2之No.1~31及45~49藉由既定之熱軋及熱軋板退火將聚落有效地破壞,結果獲得既定之低限應力強度因數。進而對所獲得之熱軋退火板之耐蝕性進行評價,結果確認到生鏽率均為25%,亦具有充分之耐蝕性。 The steel composition, hot-rolled conditions, and hot-rolled sheet annealing conditions satisfy Nos. 1 to 31 and 45 to 49 of Table 2 within the scope of the present invention. The settlement was effectively destroyed by the predetermined hot-rolled and hot-rolled sheet annealing, and the result obtained was The lower limit stress intensity factor. Furthermore, the corrosion resistance of the obtained hot-rolled annealed sheet was evaluated, and as a result, it was confirmed that the rust rates were all 25%, and they also had sufficient corrosion resistance.

尤其是,於使用Cr含量超過17%之鋼A7、A9及A14之No.7、9及14、進而使用含有Cu之鋼A17之17、及使用含有Mo之鋼A18之18中,生鏽率為10%以下,獲得更優異之耐蝕性。 In particular, the rust rate was found in Nos. 7, 9, and 14 of steels A7, A9, and A14 with a Cr content of more than 17%, furthermore, steel A17 with Cu, and steel A18 with Mo, 18 When it is 10% or less, more excellent corrosion resistance is obtained.

於最終3道之軋壓溫度超過本發明之範圍之No.32中,雖以既定之累積軋縮率進行了軋壓,但因軋壓溫度過高,故產生加工應變之恢復而再結晶位置之導入不充分,因此熱軋板退火中之聚落之破壞效果不足,結果於熱軋板退火後亦殘留大量聚落,而無法獲得既定之低限應力強度因數。 In No. 32 in which the rolling temperature of the last 3 passes exceeded the range of the present invention, although the rolling was performed at a predetermined cumulative rolling reduction rate, the rolling temperature was too high, so the processing strain was restored and the recrystallization position occurred. The introduction is not sufficient, so the destruction effect of the settlement in the hot-rolled sheet annealing is insufficient. As a result, a large number of settlements remain after the hot-rolled sheet annealing, and the predetermined low limit stress intensity factor cannot be obtained.

於最終3道之累積軋縮率低於本發明之範圍之No.33中,於熱軋板退火步驟中無法充分獲得聚落破壞效果,結果於熱軋板退火後亦於板厚中央部殘留大量聚落,而無法獲得既定之低限應力強度因數。 In No. 33 in which the cumulative rolling reduction rate in the last 3 passes was lower than the range of the present invention, the settlement failure effect could not be fully obtained in the annealing step of the hot-rolled sheet. As a result, a large amount of residue remained in the center of the plate thickness after the annealing of the hot-rolled sheet Settle, and the established low limit stress intensity factor cannot be obtained.

於熱軋板退火溫度超過本發明之範圍之No.34中,產生所生成之再結晶粒之顯著粗大化,結果無法獲得既定之低限應力強度因數。 In No. 34, where the annealing temperature of the hot-rolled sheet exceeds the range of the present invention, a significant coarsening of the recrystallized grains generated is generated, and as a result, a predetermined low limit stress intensity factor cannot be obtained.

No.36係將鋼坯以1300℃加熱1h後供至熱軋並將精熱軋之最終3道之軋壓溫度範圍均設為超過1100℃之例。於No.36中,於最終3道之軋壓實施中產生加工應變之恢復而再結晶位置之導入變得不充分,因此由熱軋板退火產生之聚落之破壞效果變得不 充分,結果無法獲得既定之低限應力強度因數。 No. 36 is an example in which the slab is heated at 1300 ° C for 1 hour and then supplied to hot rolling, and the rolling temperature range of the last three passes of finishing hot rolling is set to exceed 1100 ° C. In No. 36, the restoration of processing strain occurred during the final 3 passes of rolling and the introduction of the recrystallized position became insufficient. Therefore, the destruction effect of the settlement caused by the annealing of the hot-rolled sheet became insufficient, and as a result, it was impossible. Obtain a predetermined low limit stress intensity factor.

於最終3道之軋壓溫度範圍於3道中均低於本發明之範圍之No.37中,軋壓負重顯著上升,於最終第3道之軋壓實施時,負重超過裝置容許範圍,因此無法完成軋壓,無法進行既定評價。 In No. 37 where the rolling temperature range of the last 3 passes was lower than the range of the present invention in 3 passes, the rolling load increased significantly. When the final rolling pass was implemented, the load exceeded the allowable range of the device, so it was impossible Rolling is completed and the evaluation cannot be performed.

於使用Ni含量低於本發明之範圍之鋼B1~B4之No.38~41中,雖進行了既定之熱軋及熱軋板退火,但沃斯田鐵相之生成能力下降,結果熱軋步驟中之聚落破壞效果不足,而無法獲得既定之低限應力強度因數。 In steels B1 to B4 using No. 38 to 41 in which the Ni content is lower than the range of the present invention, although the predetermined hot rolling and hot rolled sheet annealing have been performed, the production capacity of the iron phase of Vostian decreases, resulting in hot rolling. The settlement failure effect in the step is insufficient, and the predetermined low limit stress intensity factor cannot be obtained.

於使用Cr含量超過本發明之範圍之鋼B5之No.42中,雖含有既定之Ni,但因含有過量之Cr而沃斯田鐵相之生成能力下降,結果熱軋步驟中之聚落破壞效果不足,而無法獲得既定之低限應力強度因數。 In the steel No. 42 using steel B5 whose Cr content exceeds the range of the present invention, although the predetermined Ni is contained, the generation ability of the Vostian iron phase is reduced due to the excessive Cr content, and as a result, the destruction effect of aggregation in the hot rolling step is caused. Insufficient to obtain the established low limit stress intensity factor.

於使用Ti含量低於本發明之範圍之鋼B6之No.43中,產生因於熱軋板退火時Cr碳氮化物大量析出引起之敏化,而無法獲得既定之耐蝕性。另一方面,於使用Ti含量超過本發明之範圍之鋼B7之No.44中,因含有過量之Ti而再結晶溫度上升,即便進行既定之熱軋板退火,亦不產生充分之再結晶而聚落殘留,結果無法獲得既定之低限應力強度因數。 In steel No. 43 using steel B6 whose Ti content is lower than the range of the present invention, the sensitization caused by the precipitation of Cr carbonitride during the annealing of the hot-rolled sheet, and the predetermined corrosion resistance cannot be obtained. On the other hand, in steel No. 44 using steel B7 whose Ti content exceeds the range of the present invention, the recrystallization temperature increases due to the excessive Ti content, and even if the predetermined hot-rolled sheet annealing is performed, sufficient recrystallization does not occur. Settlement remains, and as a result, the established low limit stress intensity factor cannot be obtained.

於熱軋板退火溫度低於本發明之範圍之No.50中,再結晶不充分,因此無法獲得充分之聚落之破壞效果,而無法獲得既定之低限應力強度因數。 In No. 50 where the annealing temperature of the hot-rolled sheet is lower than the range of the present invention, the recrystallization is insufficient, so that the destruction effect of sufficient settlement cannot be obtained, and the predetermined low limit stress intensity factor cannot be obtained.

(產業上之可利用性)     (Industrial availability)    

本發明所獲得之肥粒鐵系不鏽鋼熱軋退火鋼板可尤佳地應用於要求較高之加工性及耐蝕性之用途、例如具有去毛刺加 工部之凸緣等。 The ferritic iron-based stainless steel hot-rolled annealed steel sheet obtained by the present invention can be particularly suitably used for applications requiring high workability and corrosion resistance, such as flanges having a deburring processing section.

Claims (4)

一種肥粒鐵系不鏽鋼熱軋退火鋼板,其具有以質量%計,含有:C:0.001~0.020%、Si:0.05~1.00%、Mn:0.05~1.00%、P:0.04%以下、S:0.01%以下、Al:0.001~0.100%、Cr:10.0~19.0%、Ni:0.65~1.50%、Ti:0.10~0.40%、N:0.001~0.020%且剩餘部分包含Fe及不可避免之雜質的成分組成,且低限應力強度因數K IC為35MPa.m 1/2以上。 A hot-rolled and annealed steel sheet of ferrous iron-based stainless steel, which has a mass percentage of: C: 0.001 to 0.020%, Si: 0.05 to 1.00%, Mn: 0.05 to 1.00%, P: 0.04% or less, and S: 0.01 % Or less, Al: 0.001 to 0.100%, Cr: 10.0 to 19.0%, Ni: 0.65 to 1.50%, Ti: 0.10 to 0.40%, N: 0.001 to 0.020%, and the remainder contains Fe and unavoidable impurity composition , And the low limit stress intensity factor K IC is 35MPa. m 1/2 or more. 如請求項1之肥粒鐵系不鏽鋼熱軋退火鋼板,其中,上述成分組成以質量%計,進而含有選自:Cu:0.01~1.00%、Mo:0.01~2.00%、W:0.01~0.20%、Co:0.01~0.20%中之1種或2種以上。     The ferritic iron-based stainless steel hot-rolled annealed steel sheet according to claim 1, wherein the above-mentioned component composition is measured in mass% and further contains a member selected from: Cu: 0.01 to 1.00%, Mo: 0.01 to 2.00%, and W: 0.01 to 0.20% Co: one or more of 0.01 to 0.20%.     如請求項1或2之肥粒鐵系不鏽鋼熱軋退火鋼板,其中,上述成分組成以質量%計,進而含有選自:V:0.01~0.20%、Nb:0.01~0.10%、 Zr:0.01~0.20%、REM:0.001~0.100%、B:0.0002~0.0025%、Mg:0.0005~0.0030%、Ca:0.0003~0.0030%中之1種或2種以上。     For example, the ferritic iron-based stainless steel hot-rolled annealed steel sheet according to claim 1 or 2, wherein the above-mentioned component composition is based on mass% and further contains a member selected from the group consisting of: V: 0.01 to 0.20%, Nb: 0.01 to 0.10%, and Zr: 0.01 to One or more of 0.20%, REM: 0.001 to 0.100%, B: 0.0002 to 0.0025%, Mg: 0.0005 to 0.0030%, Ca: 0.0003 to 0.0030%.     一種肥粒鐵系不鏽鋼熱軋退火鋼板之製造方法,其係請求項1至3中任一項之肥粒鐵系不鏽鋼熱軋退火鋼板之製造方法,其具有:進行3道以上之精軋之熱軋步驟;及對藉由該熱軋步驟所獲得之熱軋鋼板以600~1100℃進行熱軋板退火之熱軋板退火步驟,於上述熱軋步驟中,針對精軋之最終3道,將溫度設為800~1100℃且將上述最終3道之累積軋縮率設為25%以上。     A method for manufacturing a hot-rolled and annealed steel sheet of ferrous-iron-based stainless steel, which is a method for manufacturing a hot-rolled and annealed steel sheet of ferrous-iron-based stainless steel according to any one of claims 1 to 3, which comprises: A hot rolling step; and a hot-rolled sheet annealing step of hot-rolled sheet annealing of the hot-rolled steel sheet obtained by the hot-rolling step at 600 to 1100 ° C. In the above-mentioned hot-rolling step, for the final three passes of finishing rolling, The temperature was set to 800 to 1100 ° C, and the cumulative rolling reduction rate of the last three passes was set to 25% or more.    
TW107114282A 2017-04-27 2018-04-26 Hot rolled annealed steel plate of ferrite grain stainless steel and manufacturing method thereof TWI685574B (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2017087756 2017-04-27
JP2017-087756 2017-04-27

Publications (2)

Publication Number Publication Date
TW201843316A true TW201843316A (en) 2018-12-16
TWI685574B TWI685574B (en) 2020-02-21

Family

ID=63919905

Family Applications (1)

Application Number Title Priority Date Filing Date
TW107114282A TWI685574B (en) 2017-04-27 2018-04-26 Hot rolled annealed steel plate of ferrite grain stainless steel and manufacturing method thereof

Country Status (9)

Country Link
US (1) US20200385835A1 (en)
EP (1) EP3587610B1 (en)
JP (1) JP6432720B1 (en)
KR (1) KR20190131528A (en)
CN (1) CN110546294B (en)
ES (1) ES2924685T3 (en)
MX (1) MX2019012549A (en)
TW (1) TWI685574B (en)
WO (1) WO2018199062A1 (en)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2019087761A1 (en) * 2017-10-30 2019-05-09 Jfeスチール株式会社 Ferritic stainless-steel sheet and method for manufacturing same
CN112888802A (en) * 2018-10-25 2021-06-01 杰富意钢铁株式会社 Ferritic stainless steel hot-rolled annealed steel sheet and method for producing same
US20220017984A1 (en) * 2018-12-11 2022-01-20 Jfe Steel Corporation Ferritic stainless steel sheet and method for producing same
TWI703220B (en) * 2020-01-06 2020-09-01 中國鋼鐵股份有限公司 Automobile steel and method of manufacturing the same
CN112474792B (en) * 2020-10-26 2023-03-24 邯郸钢铁集团有限责任公司 Cogging rolling production method for industrial pure iron

Family Cites Families (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5254184A (en) * 1992-06-05 1993-10-19 Carpenter Technology Corporation Corrosion resistant duplex stainless steel with improved galling resistance
JP3422871B2 (en) * 1995-04-11 2003-06-30 新日本製鐵株式会社 Ferritic stainless steel with excellent weldability
JP4239257B2 (en) * 1998-11-02 2009-03-18 Jfeスチール株式会社 Method for producing Ti-containing ferritic stainless steel sheet having excellent ridging resistance
JP3446667B2 (en) * 1999-07-07 2003-09-16 住友金属工業株式会社 Ferritic stainless steel, ferritic stainless steel ingot excellent in workability and toughness, and method for producing the same
JP2001181798A (en) * 1999-12-20 2001-07-03 Kawasaki Steel Corp Hot rolled ferritic stainless steel sheet excellent in bendability, its manufacturing method, and method of manufacturing for cold rolled steel sheet
JP2001181742A (en) * 1999-12-27 2001-07-03 Kawasaki Steel Corp Method for producing ferritic stainless cold rolled steel sheet and stainless hot rolled steel sheet used for the method
JP3448542B2 (en) * 2000-04-13 2003-09-22 新日本製鐵株式会社 Ferritic stainless steel sheet excellent in formability and ridging properties and method for producing the same
JP3680272B2 (en) * 2001-01-18 2005-08-10 Jfeスチール株式会社 Ferritic stainless steel sheet and manufacturing method thereof
JP3709833B2 (en) * 2001-10-31 2005-10-26 Jfeスチール株式会社 Ferritic stainless steel sheet and manufacturing method thereof
JP5258253B2 (en) * 2006-11-21 2013-08-07 新日鐵住金ステンレス株式会社 Surface-treated stainless steel plate for automobile fuel tanks and automobile fuel pipes with excellent salt corrosion resistance and welded part reliability, and surface-treated stainless steel welded pipes for automobile oil supply pipes with excellent pipe expansion workability
JP2012167298A (en) * 2011-02-09 2012-09-06 Nakayama Steel Works Ltd Ferritic stainless steel sheet and method for manufacturing the same
WO2014142302A1 (en) * 2013-03-14 2014-09-18 新日鐵住金ステンレス株式会社 Ferritic stainless steel sheet exhibiting small increase in strength after thermal aging treatment, and method for producing same
KR101712333B1 (en) * 2013-03-25 2017-03-03 닛폰 스틸 앤드 스미킨 스테인레스 스틸 코포레이션 Ferritic stainless steel sheet with excellent blanking workability and process for manufacturing same
WO2014157576A1 (en) 2013-03-27 2014-10-02 新日鐵住金ステンレス株式会社 Hot-rolled ferritic stainless-steel plate, process for producing same, and steel strip
JP5908936B2 (en) * 2014-03-26 2016-04-26 新日鐵住金ステンレス株式会社 Ferritic stainless steel sheet for flange, manufacturing method thereof and flange part
MX2017005210A (en) * 2014-10-31 2017-07-26 Nippon Steel & Sumikin Sst Ferrite-based stainless steel plate, steel pipe, and production method therefor.
WO2017013850A1 (en) * 2015-07-17 2017-01-26 Jfeスチール株式会社 Ferrite-based hot-rolled stainless steel sheet, hot-rolled annealed sheet, and method for manufacturing said sheets
WO2018074164A1 (en) * 2016-10-17 2018-04-26 Jfeスチール株式会社 Hot-rolled and annealed ferritic stainless steel sheet and method for producing same

Also Published As

Publication number Publication date
JPWO2018199062A1 (en) 2019-06-27
JP6432720B1 (en) 2018-12-05
TWI685574B (en) 2020-02-21
KR20190131528A (en) 2019-11-26
WO2018199062A1 (en) 2018-11-01
CN110546294A (en) 2019-12-06
EP3587610A1 (en) 2020-01-01
US20200385835A1 (en) 2020-12-10
EP3587610A4 (en) 2020-03-04
ES2924685T3 (en) 2022-10-10
CN110546294B (en) 2022-03-22
MX2019012549A (en) 2019-12-02
EP3587610B1 (en) 2022-07-06

Similar Documents

Publication Publication Date Title
KR101492753B1 (en) High strength hot rolled steel sheet having excellent fatigue resistance and method for manufacturing the same
TWI685574B (en) Hot rolled annealed steel plate of ferrite grain stainless steel and manufacturing method thereof
CN109642286B (en) Ferritic stainless steel hot-rolled annealed steel sheet and method for producing same
CN110225988B (en) Hot rolled ferritic stainless steel sheet and method for producing same
JP5884211B1 (en) Ferritic stainless steel sheet and manufacturing method thereof
JP5987996B2 (en) Ferritic stainless steel and manufacturing method thereof
TWI605134B (en) Fertilizer-grained stainless steel hot-rolled steel sheet and hot-rolled annealing sheet, and methods for producing the same
KR102603113B1 (en) Ferritic stainless-steel sheet and method for manufacturing same
JP2010229514A (en) Cold rolled steel sheet and method for producing the same
CN113166831B (en) Ferritic stainless steel sheet and method for producing same
JP6024401B2 (en) Manufacturing method of thick steel plate with excellent surface quality
JP2001207244A (en) Cold rolled ferritic stainless steel sheet excellent in ductility, workability and ridging resistance, and its manufacturing method
JP6304469B1 (en) Ferritic stainless steel hot rolled annealed steel sheet and method for producing the same
JP7038799B2 (en) Ferritic stainless hot-rolled annealed steel sheet and its manufacturing method
JP2020152941A (en) Two-phase stainless steel, and method for manufacturing the same