TW201042056A

TW201042056A - Corrosion resistant steel for crude oil tank, manufacturing method therefor, and crude oil tank

Info

Publication number: TW201042056A
Application number: TW99102654A
Authority: TW
Inventors: Yasuto Inohara; Kazuhiko Shiotani; Tsutomu Komori; Kimihiro Nishimura
Original assignee: Jfe Steel Corp
Priority date: 2009-01-30
Filing date: 2010-01-29
Publication date: 2010-12-01
Also published as: JP2010196166A; EP2395120A4; EP2395120B1; EP2395120A1; KR20110089205A; KR20130029436A; CN102301025B; JP4640529B2; TWI410503B; KR20160049023A; WO2010087509A1; CN102301025A

Abstract

Disclosed is a corrosion resistant steel for crude oil tank, which not only has excellent resistance to general corrosion and local corrosion, but also has excellent corrosion resistance in cases the steel is used in a condition with Zn present on the steel surface. Specifically, the corrosion resistant steel for crude oil tank contains, in mass%, C: 0.001-0.16%, Si: 1.5% or less, Mn: 0.1-2.5%, P: 0.025% or less, S: 0.01% or less, Al: 0.005-0.1%, N: 0.001-0.008%, Cu: 0.008-0.35%, Cr: greater than 0.1% and 0.5% or less, and Sn: 0.005-0.3%, wherein Mo: 0.01% or less, and the value for A1, defined by the formula, is 0 or less. A1 = 28 [C] + 2000 [P]2 + 27000 [S]2 + 0.0083 (1/[Cu]) + 0.027 (1/[Cr]) + 95 [Mo] + 0.00098 (1/[Sn]) - 6

Description

201042056 六、發明說明：【發明所屬之技術領域】本發明係關於適合使用於原油油輪（crude oil tanker )之油槽（oil tank)或輸送或者貯藏原油（crude oil) 用之油槽（以下總稱爲「原油油槽（crude oil tank)」）之鋼材（steel products)，具體而言，係關於一種可減輕於原油油槽之頂部（top part)或側壁部（sidewall part) 0 、底部（bottom part)之鋼材表面上發生的全面腐纟虫（ general corrosion)及原油油槽之底板（bottom plate)上發生之局部腐蝕（local corrosion)的鋼材。此外，本發明之原油油槽用鋼材係含厚鋼板（thick steel plate)、薄鋼板（thin stee丨 sheet)及形鋼（shaped steel)者。【先前技術】已知，目前用於油輪之原油油槽的內面，特別是上甲板的裏面（back side of upper deck)及側壁部上部（ upper part )之鋼材上，會發生全面腐餓。而引發全面腐蝕的原因，係可舉出有 (1 )晝夜的溫差所致對鋼板面的結露（dew drop ) 與反覆的乾濕（alternate wetting and drying)、 (2)原油油槽內爲了防爆（explosion protection) 用所封入之惰性氣體（i n e r t g a s )(以Ο 2約5 ν ο 1 %、C Ο 2 約13vol%、S02約0·01ν〇1%、殘餘部分爲Ν2作爲代表組成之鍋爐（boiler )或是引擎（engine )的排放氣體（ 201042056 exhaustgas))中之〇2、C〇2、S02對結露水之溶入、 (3 )對由原油揮發之H2S等之腐蝕性氣體對結露水 (dew condensation water )之溶入、 (4)原油油槽之洗淨（cleaning)中所使用之海水（ salt water )的殘留等。此等係由實際的碼頭稽查（dock inspection)時的調査中，因檢出強酸性（strong acidity )之結露水，以及硫酸離子（sulfate ion )及氯化物離子 (chloride ion)而得知。再者，因腐蝕生成之鐵鏽（iron rust)可作爲觸媒（ catalyst)而氧化 H2S，使固體 S ( elemental sulfur)在鐵鏽中呈層狀生成，此等之腐餓生成物（corrosion product )因容易剝離而脫落，會堆積於原油油槽之底部。因此，目前的現況是在每2.5年碼頭稽查中，會花費掉龐大的費用，來進行油槽上部之補修（maintenance and repair)或油槽底部堆積物（deposited material)的回收。另外，在油輪之原油油槽的底板中，可藉由原油本身的腐触抑制作用（corrosion inhibition function)或形成於原油油槽內面之來自原油的保護性被膜（pr〇tective coating )(以下稱爲「油脂被膜」）之腐蝕抑制作用，而認爲所使用之鋼材上不會發生腐蝕。但是，最近的硏究發現，油槽底板之鋼材上，會發生碗型（bowl-shaped)的局部腐餓（孔触（pitting corrosion))。至於局部腐倉虫的原因方面’雖可舉出以下等項目，但都只不過是推論而以，明確的原因尙未明朗， -6- 201042056 (1)氯化鈉（sodium chloride)爲代表之溶解濃度鹽類之凝集水（brine)的存在、 (2 )因過度洗淨所致之油脂被膜的脫離、 (3 )原油中之硫化物（sulfide )的高濃度化、 (4 )原油油槽內防爆用所封入之惰性氣體中之 co2、so2的高濃度化、 (5)微生物（microorganism)等的參與， 0 此外，實際在碼頭稽查時的原油油槽內之滯留水析中，係檢出有高濃度的氯化物離子與硫酸離子。因此，抑制上述全面腐蝕或局部腐蝕最有效的方於鋼材表面上施予重塗裝（heavy coating)，使鋼材蝕環境（corrosion environment )中遮斷之方法《但指出在原油油槽之塗裝作業時，其塗佈面積膨大，且膜之劣化，約每1 〇年必須進行一次塗換之故，在檢塗裝上會產生巨大費用。再者亦被指出，經重塗裝之〇的損傷部分在原油油槽環境下，反而會助長腐蝕。針對上述腐蝕之問題，係提案有幾個改善鋼材本耐蝕性而於原油油槽環境中亦具有耐蝕性之耐蝕鋼。例如，在專利文獻1中係揭示有一種貨油艙（（ oil tank )用之耐蝕鋼，其係於以質量％計爲含有C : 〜0.3%之鋼上，添加適量的 Si、Μη、P、S以及 0.05〜3%再選擇性地添加Mo、Cu、Cr、W、Ca、Ti 、V、B而改善了對全面腐蝕或局部腐鈾之抵抗性者。此外，在含有H2S之反覆乾濕的環境中，因若（有高的分法係自腐確被因塗査及塗膜身的：argo 0.0 1 Ni ：、Nb :r的 201042056 含量超過〇.〇5質量％則耐全面腐飩性與肺降低，而揭示Cr的含量爲〇· 05質量％以下又，專利文獻2中揭示有一種原油油朽其係藉由在以質量％計爲含有C:0·001〜添加適量的Si、Μη、P、s以及Cu: 0.01 0.001 〜0.3%、N: 0.001 〜0·01%，再添文 0.2%或W: 0.01〜0.5%之至少一者而成5 及耐局部腐蝕性優異且可抑制含固體S之雇成者。又，專利文獻3中係揭示有一種貨拍 tank )用的耐蝕鋼，其係藉由在以質量％ 0.01〜0.2%之鋼上，添加適量的 Si、Μη 0.01 〜2%、Cu: 0_05〜2% ' w: 0.01 〜1% 添加Cr、Al、N、0’進一步以參數式規定添加量，而使全面腐餓或局部腐触向上提昇又’專利文獻4中係揭示有一種貨油 tank)用的耐触鋼’其係藉由在以質量％ 0_01〜0_2%之鋼上’添加適量的si、Mn、及 Ni: 0.01 〜1%、Cu: 0.05 〜2%、Sn: 再選擇性地添加Mo、W、Ti、Zl_、Sb、c: 、B，而使其對全面腐蝕或局部腐蝕之抵抗 [先前技術文獻] [孔飩性會顯著〇 I用的耐蝕鋼， 0. 2%之鋼上，〜1 .5 %、A1 : |口 Μ 〇 : 0.0 1 〜 :耐全面腐蝕性 ί蝕生成物的生丨艙(cargo oil 計爲含有C : 、P以及Ni : ;，再選擇性地 Cu、Ni、W 的 .者。丨艙(cargo oil 計爲含有C : P 、 Cr 、 A1 以 0· 0 1 〜0.2 % ， 1、 M g、Nb、V ,性向上提昇者 -8 - 201042056 [專利文獻] [專利文獻1]特開2003-082435號公報 [專利文獻2]特開20〇4_2〇4344號公報 [專利文獻3]特開2005-325439號公報 [專利文獻4]特開20〇7_27〇196號公報【發明內容】 0 [發明所欲解決之課題] 但是，在原油油槽中使用上述專利文獻1〜4中所揭示之耐蝕鋼時’對當其用於原油油槽之上部時之全面腐餓而言的抵抗性（以下稱爲「耐全面腐蝕性」），或對當其用於原油油槽底板時之局部腐蝕而言的抵抗性（以下稱爲「耐局部腐蝕性」），很難說已經十分地充分。此係顯示出’在開發對於原油油槽之上部甲板裏的全面腐蝕或底板的局部腐蝕之各耐蝕鋼的過程中，若單僅以〇模擬各自腐蝕環境而進行耐蝕性試驗的話，並不充分。此謂實驗室中的腐蝕試驗（corrosion test)因爲包含不少促進試驗（accelerating test)的要素，或有一部分腐蝕因子 (corrosion factor)被省略，而會有無法正確地使現實環境（actual environment )再現的情況，特別是在原油油槽用的耐蝕鋼之開發上，必須於試驗環境中添加氯化物離子及硫酸離子。又，專利文獻3及4中所記載的發明，係考量在原油非積載時，位於貨油艙（cargo oil tank )之外側的壓載艙 201042056 (ballast tank)內係積載有海水，以兼具原油腐蝕環境及海水腐蝕環境中之耐蝕性爲其目標之技術。但是，此等之技術對海水腐独環境而言’在貨油艙（carg〇 oil tank)外面之防蝕塗膜劣化後的耐蝕性方面，雖著眼於鋼材本身所具有的耐蝕性’但就起因於鋼材所含有的耐鈾性元素與與富鋅底漆中之Zn的相乘效果而於鋼材表面存在塗膜之狀態下的耐蝕性、意即塗裝後耐蝕性的提昇方面，並未有任何考量。但是，使專利文獻3及4中未有所考量之塗裝後耐蝕性向上提昇，雖在企圖使原油油輪用耐蝕鋼材長壽化上極爲重要且有效，但現階段，現實上並未存在有能實現此等之技術。因此，本發明係爲了解決上述課題而開發所致，其目的在於提供一種用於原油油槽內面，特別是用於上甲板及側板時具有優異的耐全面腐蝕性，同時在用於原油油槽底板時具有優異的耐局部腐蝕性，進一步在鋼材表面存在 Ζη之狀態下使用時，會發揮顯著、優異的耐全面腐蝕性及耐局部腐蝕性之原油油槽用鋼材、其製造方法、及使用該鋼材之原油油槽。 [解決課題之方法] 發明者等爲了達成上述課題，首先，抽出原油油槽內有關全面腐蝕之因子而進行組合該等因子之腐蝕試驗（ corrosion test)。其結果成功地再現了原油油槽內所產生 -10- 201042056 的全面腐蝕，而就全面腐蝕之支配因子及腐餓機制（ corrosion mechanism) ’ 得到了以下的見解。原油油槽內爲了防爆所封入的惰性氣體中含有水蒸氣。因此，在航海中之晝夜的溫差下會於油槽內壁之鋼材表面產生結露。此結露水中’溶有情性氣體成分之C〇2 (二酸化炭素）或〇2 (酸素）、S02 (二酸化硫）及自原油揮發之成分H2S (硫化水素）等’會生成含硫酸離子之腐蝕 0 性的酸性溶液。也必須考慮原油油槽因海水洗淨所挾帶進來之氯化物離子（Chloride ion )。溶入有此等成分之腐蝕性的酸性溶液（acid solution ) ’在鋼板溫度上昇的過程中會濃化，而於鋼板表面發生全面腐蝕。甚至’因在鋼板表面上形成的鐵鏽作爲觸媒，而從H2s析出S (硫），故形成鐵鏽與硫之層狀的鏽層，鋼板表面之鏽層會成爲脆而無保護性者，腐蝕會繼續地進行。因此，發明者等係在含有硫酸離子及氯化物離子之結 G 露水存在的環境下，就可能導致鋼板表面之全面腐蝕的各種合金元素之影響進行了調査。其結果可確認，Cu、Cr 及Sn的添加，會使在用爲原油油槽用鋼材之環境中所形成之鋼板表面的鏽層緻密化，且使其耐全面腐蝕性向上提昇，又可確認，W及Sb的添加會促進緻密鏽層之生成，而使其耐全面腐蝕性向上提昇。意即發明者等發現，藉由主要添加Cu、Cr及Sn，且再進一步適量地添加W及Sb ’係可獲得耐全面腐蝕性優異之原油油槽用鋼材。接著，發明者們係抽出有關原油油槽底板之局部腐蝕 -11 - 201042056 的因子’來進行組合該等因子所成的腐蝕試驗。其結果係與全面腐蝕同樣地，成功地再現了原油油槽底板所產生之局部腐蝕，而就局部腐蝕之支配因子及腐鈾機制獲得了以下的見解。實際在原油油槽底板產生的碗型局部腐蝕，係因底板上滯留的溶液中所含的02及H2S爲主要支配因子的作用，具體而言，在02與H2S共存，且02濃度與H2S濃度雙方均在某個範圍的環境下（使〇2濃度：2〜8vol%、H2S 濃度：〇·1〜5vol%之氣體飽和的水溶液中）會產生局部腐蝕。換言之，在低〇2濃度且低H2S濃度的環境下， H2S會被氧化而析出固體S。此析出的固體S會於與原油油槽底板之間會形成局部電池，導致鋼材表面上局部腐蝕。此局部腐蝕若在氯化物離子及硫酸離子存在之酸性環境下會進一步受到促進而成長。因此，發明者等係在上述低〇2濃度及低H2S濃度的環境下就可能導致其局部腐蝕發生的各種合金元素之影響進行了調査。其結果可確認，W的添加，會使在用爲原油油槽用鋼材之環境中所形成之鋼板表面的鏽層緻密化，且使其耐局部腐蝕性向上提昇，又可確認，Sn及Sb的添加有助於含W之緻密鏽層的生成，而使其耐局部腐飩性向上提昇。此外可確認，在氯化物離子及硫酸離子雙方同時存在之酸性腐蝕環境中，M 〇的添加反而會使耐触性劣化。意即，除了 w的添加之外，藉由適量地添加s η及S b 且限制Mo含量，係可獲得耐局部腐蝕性優異之原油油槽 -12- 201042056 用鋼材。由以上見解的結果得知，藉由適切化Cu、Cr、Sn、 W及Sb含量，可獲得在用於原油油槽內面時具有優異的耐全面腐蝕性，同時在用於原油油槽底板時具有優異的耐局部腐蝕性，意即’不管用於原油油槽內之任何部位’皆可獲得耐蝕性優異的原油油槽用鋼材。又，發明者們發現’上述Cu、Cr、Sn、W及Sb含量 0 經適切化之鋼材，即使在無塗裝的狀態亦具有優異的耐蝕性，且在使用表面施以含金屬Zn或是Zn化合物之塗裝時，除了可大大地延長其塗裝壽命，在耐全面腐蝕性及耐局部腐蝕性亦有顯著的提昇。又，調查本發明之鋼材中鋼的微細組織（microstructure)對耐蝕性之影響，因會生成面積率在2%以上之波來鐵（perlite )，而可使耐蝕性向上提昇。本發明係基於上述見解，再進一步加以檢討所成者。〇意即’本發明係一種原油油槽用耐飩鋼材，其特徵係含有C: 0.001〜0.16質量％、Si: 1.5質量％以下、Μη: 0_1〜2.5質量％、Ρ: 0.025質量％以下、S: 0.01質量％以下、Α1: 0.005 〜0.1 質量％、Ν: 0.001 〜0.008 質量％、Cu: 0.008 〜0.35 質量％ ' Cr: 0.1 質量％超〇.5 質量％以下、Sn: 0.005〜〇·3質量％，且由Mo: 〇.〇1質量％以下、殘餘部分爲Fe及不可避免之雜質所成’其中，以下述（1 )式所定義之A1的値爲0以下； -13- 201042056 A1 = 28X [C] + 2000X [P] 2+27000Χ [S] 2 + 0. 008 3 X (1/ [Cu] ) + 0. 027X (l/[Cr]) +95X [Mo] + 0. 00098X (l/[Sn]) -6 . · · (1) 在此，上述式中之〔c〕、〔P〕、〔S〕、〔Cu〕 ' 〔Cr〕、〔 Mo〕及〔Sn〕係各自之元素的含量（質量％ )° 本發明之原油油槽用耐蝕鋼材係除了上述成分組成之外，進一步含有Ni: 0.005〜0.4質量％，且以下述（2) 式所定義之A2的値爲0以下； A2 = 28X [C] +2 0 0 0 X [P] 2+ 2 7 0 0 0 X [S] 2+0· 008 3X (1/ [Cu] ) +2X [N i] +0. 027X (l/[Cr]) +95X [Mo] +0. 00098X (l/[Sn]) —6 · · · (2) 在此，上述式中之〔C〕、 [ P ] 、〔S〕、〔Cu〕、〔Ni〕、〔 Cr〕、〔 Mo〕及〔Sn〕係各自之元素的含量 (質量％ )。又，本發明之原油油槽用耐蝕鋼材係除了上述成分組成之外，進一步含有由 W: 0.001〜0.5質量％及 Sb: 0.005〜0.3質量％之中選出的1種或2種，且以下述（3 )式所定義之A3的値爲0以下； A3 = 28X [C] +2 0 0 0X [P] 2+2 7 0 0 0 X [S] 2+〇· 〇〇8201042056 VI. Description of the Invention: [Technical Field] The present invention relates to an oil tank suitable for use in a crude oil tanker or an oil tank for transporting or storing crude oil (hereinafter collectively referred to as " Steel products of a crude oil tank, in particular, a steel material that can be alleviated in the top part or the side wall part 0 and the bottom part of the crude oil tank. A steel that has a general corrosion on the surface and local corrosion occurring on the bottom plate of the crude oil sump. Further, the steel material for a crude oil sump of the present invention is a thick steel plate, a thin steel plate (thin stee 丨 sheet), and a shaped steel. [Prior Art] It is known that the inner surface of the crude oil sump currently used for the oil tanker, particularly the steel of the back side of the upper deck and the upper part of the upper side, may be completely hungered. The causes of general corrosion are: (1) dew drop and repeated wetting and drying on the steel sheet due to the temperature difference between day and night, and (2) explosion protection in the crude oil tank ( Explosion protection) Use a sealed inert gas (inertgas) (approximately 5 ν ο 1 %, C Ο 2 approximately 13 vol%, S02 approximately 0·01 ν 〇 1%, and the remainder is Ν 2 as the representative boiler (boiler) ) or the exhaust gas of the engine (201042056 exhaustgas), the dissolution of dew condensation water by 〇2, C〇2, and S02, and (3) the dew condensation of corrosive gas such as H2S volatilized by crude oil ( (d) the dissolution of dew condensation water, (4) the residue of salt water used in the cleaning of the crude oil tank. These were obtained from the investigation of the actual dock inspection by the detection of strong acidity of dew condensation water, sulfate ion and chloride ion. Furthermore, iron rust generated by corrosion can oxidize H2S as a catalyst, and solid S (formal sulfur) is formed in layers in rust, and these corrosion products are caused by It is easy to peel off and fall off, and will accumulate at the bottom of the crude oil tank. Therefore, the current situation is that in every 2.5 years of dock inspection, a huge cost will be spent to recover the maintenance and repair of the upper tank or the deposited material at the bottom of the tank. In addition, in the bottom plate of the crude oil tank of the tanker, the corrosion inhibition function of the crude oil itself or the protective coating from the crude oil formed on the inner surface of the crude oil tank may be referred to as pr〇tective coating (hereinafter referred to as The "grease film" is corrosion-inhibiting, and it is considered that corrosion does not occur on the steel used. However, recent research has revealed that bowl-shaped partial hunger (pitting corrosion) occurs on the steel of the oil sump floor. As for the causes of local rot worms, the following items can be cited, but they are all inferences. The reasons for this are unclear. -6- 201042056 (1) Sodium chloride is representative. The presence of condensed water in the dissolved concentration salt, (2) the detachment of the oil and fat film due to excessive washing, (3) the high concentration of sulfide in the crude oil, and (4) the crude oil tank Participation in the high concentration of co2 and so2 in the inert gas enclosed by explosion-proof, and (5) the participation of microorganisms (microorganism), etc. In addition, in the residual water analysis in the crude oil tank at the time of dock inspection, it was detected. High concentration of chloride ions and sulfate ions. Therefore, the most effective method for suppressing the above-mentioned general corrosion or local corrosion is to apply a heavy coating on the surface of the steel to break the corrosion environment of the steel. "But the painting operation in the crude oil tank is pointed out. At the time of coating, the coating area is swollen, and the deterioration of the film is required to be applied once every one year, which causes a huge cost in the inspection and coating. It has also been pointed out that the damaged part of the repainted crucible will contribute to corrosion in the crude oil tank environment. In response to the above-mentioned problems of corrosion, it is proposed to have several corrosion-resistant steels which have improved corrosion resistance of steel and corrosion resistance in a crude oil tank environment. For example, Patent Document 1 discloses an anti-corrosion steel for an oil tank which is added to a steel containing C: to 0.3% by mass, and an appropriate amount of Si, Μ, and P is added. , S and 0.05 to 3% and then selectively add Mo, Cu, Cr, W, Ca, Ti, V, B to improve the resistance to general corrosion or local uranium. In addition, in the H2S-containing re-drying In a wet environment, due to the fact that there is a high degree of self-destruction, it is indeed affected by the coating and coating of the body: argo 0.0 1 Ni : , Nb : r of 201042056 content exceeds 〇. 〇 5 mass% is resistant to full rot The sputum and the lung are lowered, and the content of Cr is 5%·5% by mass or less. Patent Document 2 discloses that a crude oil is obtained by adding an appropriate amount of C:0·001~ Si, Μη, P, s, and Cu: 0.01 0.001 to 0.3%, N: 0.001 to 0·01%, and add at least one of 0.2% or W: 0.01 to 0.5% to form 5 and excellent in local corrosion resistance. Further, it is possible to suppress the occupation of the solid S. Further, Patent Document 3 discloses a corrosion resistant steel for use in a tank, which is at a mass % of 0.01. On the steel of ~0.2%, add appropriate amount of Si, Μη 0.01 〜2%, Cu: 0_05~2% ' w: 0.01 〜1% Add Cr, Al, N, 0' and further add the amount according to the parameter formula, so that Fully rotted or partially rotted and lifted upwards. 'Patent Document 4 discloses a touch resistant steel for a cargo oil tank' which is obtained by adding an appropriate amount of Si to steel of mass % 0_01 to 0_2%. Mn, and Ni: 0.01 to 1%, Cu: 0.05 to 2%, Sn: Mo, W, Ti, Zl_, Sb, c:, B are selectively added to resist general or local corrosion. [Previous Technical Literature] [Corrosion-resistant steel for significant porosity, 0.2% steel, ~1.5%, A1: | 口 Μ: 0.0 1 ~ : Corrosion resistance ί The cargo tank is considered to contain C:, P, and Ni:; and then Cu, Ni, and W. The tank is considered to contain C: P, Cr, A1 to 0. In the case of the singularity of the singularity of the singularity of the singularity of the singularity of the singularity of the singularity of the singularity of the singularity of the singularity of the singularity of the sequel 〇4344 bulletin [patent document 3] special opening [Patent Document 4] Japanese Laid-Open Patent Publication No. Hei. No. Hei. No. Hei. No. Hei. Steel's resistance to full hunger when used in the upper part of the crude oil tank (hereinafter referred to as "total corrosion resistance"), or for local corrosion when used in crude oil tank bottoms Resistance (hereinafter referred to as "local corrosion resistance") is hard to say is already quite sufficient. This shows that in the process of developing corrosion-resistant steels for the full-surface corrosion of the upper deck of the crude oil tank or the local corrosion of the bottom plate, it is not sufficient to carry out the corrosion resistance test by simply simulating the respective corrosive environments. This means that the corrosion test in the laboratory cannot contain the actual environment because it contains many elements of the accelerating test, or some of the corrosion factor is omitted. In the case of reproduction, especially in the development of corrosion resistant steel for crude oil tanks, chloride ions and sulfate ions must be added to the test environment. Further, in the inventions described in Patent Documents 3 and 4, it is considered that when the crude oil is not stowed, the ballast tank located in the ballast tank outside the cargo oil tank 201042056 (ballast tank) is stowed with seawater. The corrosion resistance of crude oil in corrosive environments and seawater corrosive environments is a target technology. However, in terms of the corrosion resistance of the anti-corrosion coating film on the outside of the cargo tank, the technology of the above-mentioned technology focuses on the corrosion resistance of the steel itself, but the cause is There is no improvement in the corrosion resistance of the uranium-resistant element contained in the steel and the Zn in the zinc-rich primer, and the corrosion resistance in the state where the coating film exists on the surface of the steel, that is, the improvement in corrosion resistance after coating. Any consideration. However, the corrosion resistance after coating which has not been considered in Patent Documents 3 and 4 is increased upwards. Although it is extremely important and effective in attempting to increase the life of corrosion-resistant steel for crude oil tankers, at present, there is no energy in reality. Implement these technologies. Accordingly, the present invention has been made in order to solve the above problems, and an object thereof is to provide an inner surface of a crude oil oil tank, particularly for use in an upper deck and a side panel, which has excellent overall corrosion resistance and is used in a crude oil sump bottom plate. When it is used in a state where Ζη is present on the surface of the steel material, the steel material for crude oil sump which exhibits remarkable and excellent overall corrosion resistance and local corrosion resistance, a method for producing the same, and the use of the steel material Crude oil tank. [Means for Solving the Problem] In order to achieve the above problems, the inventors first extracted a corrosion test using a factor of general corrosion in a crude oil tank. As a result, the overall corrosion of -10- 201042056 produced in the crude oil tank was successfully reproduced, and the following findings were obtained regarding the dominant corrosion factor and the corrosion mechanism of the overall corrosion. The inert gas enclosed in the crude oil tank for the explosion-proof contains water vapor. Therefore, condensation occurs on the steel surface of the inner wall of the oil sump during the temperature difference between day and night during navigation. In the dew condensation water, C〇2 (diacidified carbon) or 〇2 (acid), S02 (diacid sulphur), and H2S (sulfur sulphide) which are volatilized from crude oil in the condensed water component will produce corrosion containing sulphate ions. Sexual acidic solution. Chloride ions from the crude oil tank due to seawater washing must also be considered. The corrosive acidic solution dissolved in these components is concentrated during the rise of the steel sheet temperature, and is completely corroded on the surface of the steel sheet. Even 'the rust formed on the surface of the steel sheet acts as a catalyst, and S (sulfur) is precipitated from H2s, so a layered rust layer of rust and sulfur is formed, and the rust layer on the surface of the steel sheet becomes brittle and unprotective, corroding Will continue. Therefore, the inventors investigated the influence of various alloying elements which may cause overall corrosion of the surface of the steel sheet in an environment in which the dew water containing sulfate ions and chloride ions existed. As a result, it was confirmed that the addition of Cu, Cr, and Sn densifies the rust layer on the surface of the steel sheet formed in the environment for the steel material for the crude oil oil tank, and the corrosion resistance is improved upward. The addition of W and Sb promotes the formation of a dense rust layer, which increases its overall corrosion resistance. In other words, the inventors have found that a steel material for a crude oil sump excellent in general corrosion resistance can be obtained by mainly adding Cu, Cr, and Sn, and further adding W and Sb ′ in an appropriate amount. Next, the inventors extracted the factors relating to the local corrosion of the crude oil sump bottom plate -11 - 201042056 to perform the corrosion test by combining the factors. As a result, the local corrosion generated by the bottom plate of the crude oil tank was successfully reproduced in the same manner as the overall corrosion, and the following factors were obtained regarding the localized corrosion dominant factor and the uranium mechanism. The actual local corrosion of the bowl produced in the bottom of the crude oil tank is due to the fact that 02 and H2S contained in the solution retained on the bottom plate are the main dominating factors. Specifically, 02 and H2S coexist, and both the 02 concentration and the H2S concentration Localized corrosion occurs in a certain range of environments (in an aqueous solution in which 〇2 concentration: 2 to 8 vol%, H2S concentration: 〇·1 to 5 vol% of gas is saturated). In other words, in an environment of a low 〇 2 concentration and a low H 2 S concentration, H 2 S is oxidized to precipitate a solid S. The precipitated solid S will form a local battery between the bottom of the crude oil tank and the local corrosion of the steel surface. This localized corrosion is further promoted and grown if it is in an acidic environment in which chloride ions and sulfate ions are present. Therefore, the inventors investigated the influence of various alloying elements which may cause local corrosion in the above-described environment of low 〇2 concentration and low H2S concentration. As a result, it was confirmed that the addition of W densifies the rust layer on the surface of the steel sheet formed in the environment for the steel material for the crude oil oil tank, and the local corrosion resistance is improved upward, and it is confirmed that Sn and Sb are The addition contributes to the formation of a dense rust layer containing W, which is enhanced in resistance to local rot. Further, it was confirmed that in the acidic corrosive environment in which both the chloride ion and the sulfate ion exist simultaneously, the addition of M 反 deteriorates the contact resistance. That is, in addition to the addition of w, by appropriately adding s η and S b and limiting the Mo content, it is possible to obtain a steel material for a crude oil sump -12- 201042056 which is excellent in local corrosion resistance. From the results of the above findings, it is found that by adapting the contents of Cu, Cr, Sn, W and Sb, it is possible to obtain excellent resistance to general corrosion when used in the inner surface of a crude oil tank, and at the same time, when used in a crude oil tank bottom plate. Excellent local corrosion resistance means that steel for crude oil tanks with excellent corrosion resistance can be obtained regardless of any part used in the crude oil tank. Moreover, the inventors have found that the above-mentioned Cu, Cr, Sn, W, and Sb steels having an appropriate content of 0 have excellent corrosion resistance even in the uncoated state, and are coated with metal-containing Zn or When the Zn compound is coated, in addition to greatly extending the coating life, the overall corrosion resistance and local corrosion resistance are also remarkably improved. Further, the influence of the microstructure of the steel in the steel of the present invention on the corrosion resistance is investigated, and the perlite having an area ratio of 2% or more is generated, and the corrosion resistance is improved upward. The present invention is based on the above findings and is further reviewed. The present invention relates to a ruthenium-resistant steel material for a crude oil oil tank, which is characterized by containing C: 0.001 to 0.16 mass%, Si: 1.5 mass% or less, Μη: 0_1 to 2.5 mass%, and Ρ: 0.025 mass% or less, S : 0.01% by mass or less, Α1: 0.005 to 0.1% by mass, Ν: 0.001 to 0.008% by mass, Cu: 0.008 to 0.35% by mass 'Cr: 0.1% by mass, more than 5% by mass, and less: 0.005 to 〇·3 % by mass, and is composed of Mo: 〇.〇1 mass% or less, and the remainder is Fe and unavoidable impurities. Among them, the enthalpy of A1 defined by the following formula (1) is 0 or less; -13- 201042056 A1 = 28X [C] + 2000X [P] 2+27000Χ [S] 2 + 0. 008 3 X (1/ [Cu] ) + 0. 027X (l/[Cr]) +95X [Mo] + 0. 00098X (l/[Sn]) -6 . (1) Here, [c], [P], [S], [Cu] '[Cr], [Mo], and [Sn] in the above formula Content of the respective elements (% by mass) The corrosion-resistant steel material for the crude oil oil tank of the present invention further contains Ni: 0.005 to 0.4% by mass in addition to the above-described component composition, and the enthalpy of A2 defined by the following formula (2) is 0 or less; A2 = 28X [C] +2 0 0 0 X [P] 2+ 2 7 0 0 0 X [S] 2+0· 008 3X (1/ [Cu] ) +2X [N i] +0. 027X (l /[Cr]) +95X [Mo] +0. 00098X (l/[Sn]) —6 · · · (2) Here, [C], [P], [S], [Cu] in the above formula And the content (% by mass) of each of [Ni], [Cr], [Mo], and [Sn]. In addition, the corrosion-resistant steel material for a crude oil oil tank of the present invention further contains one or two selected from the group consisting of W: 0.001 to 0.5% by mass and Sb: 0.005 to 0.3% by mass, in addition to the above-described component composition, and is as follows ( 3) The 値 of A3 defined by the formula is 0 or less; A3 = 28X [C] +2 0 0 0X [P] 2+2 7 0 0 0 X [S] 2+〇· 〇〇8

3X (l/[Cu]) + 2X [Ni] +0. 027X (l/[Cr]) +95X [Mo] +0. 00098X (l/[Sn]) +0. 0019X (1/([S b] + [W] ) ) -6. 5 • · · (3) 在此，上述式中之〔c〕、〔P〕、〔S〕、 [ Cu ]、 -14- 201042056 〔Ni〕、〔Cr〕、〔Mo〕、〔Sn〕、〔31»〕及〔'^〕係各自之元素的含量（質量％)。又，本發明之原油油槽用耐蝕鋼材係除了上述成分組成之外，進一步含有由 Nb: 0.002〜0.1質量％、V: 0.002 〜0.1 質量％、Ti: 0.001 〜0.1 質量％及 Β: 〇·(Η 質量％以下之中選出的1種或2種以上。又，本發明之原油油槽用耐蝕鋼材係除了上述成分組 0 成之外，進一步含有由Ca: 0.00 02〜0.005質量％及rem :0.0005〜0.015質量％之中選出的1種或2種。又，本發明之原油油槽用耐蝕鋼材，其鋼材之板厚 1/4位置之微組織係含有以面積率計爲2〜20%之波來鐵〇又，本發明之原油油槽用耐蝕鋼材，其係在鋼材的表面形成有含金屬Zn或Zn化合物之塗膜而成。又，本發明之原油油槽用耐蝕鋼材，其中，塗膜中之 ❹ Zn含墓爲l.〇g/m2以上。又，本發明係提案一種原油油槽用耐蝕鋼材之製造方法，其係將上述之成分組成的鋼素材加熱至1 000〜1 3 5 0 °c 後，使壓延後製溫度爲75 0°C以上進行熱間壓延，且以 2°C/sec以上之冷卻速度冷卻至650°C以下、450°C以上之冷卻停止溫度爲止。又本發明係特徵爲使用上述鋼材之原油油槽。 [發明之效果] -15- 201042056 根據本發明，係因可便宜地提供即使用於原油油輪之油槽或輸送或貯藏原油用之油槽等的原油油槽之任何部位均不會發生全面腐蝕或局部腐蝕之鋼材，而在產業上具有極佳的效果。【實施方式】 [實施發明之最佳形態] 以下’係就將本發明之原油油槽用鋼材的成分組成限定於上述範圍之理由進行說明。 C: 0.00 1 〜0.16 質量％ c係提高鋼材強度的元素，本發明中，爲了獲得所期望的強度’必須含以0 · 0 0 1質量％以上。另一方面，C不僅會隨著含量的增加而使耐蝕性劣化，當添加超過〇. i 6 質量％ ’會使熔接性（weldability )及熔接熱影響部（ welded heat affected zone)的韋刃性（toughness)劣化。因此，C設爲〇·〇〇1〜0.16質量％之範圍。此外，若從使強度、韌性更向上提昇之觀點來看，係以0.01〜〇.丨5質量％之範圍爲佳，0.〇1〜0.15質量％之範圍更佳。 -16- 1 i : 1 . 5質量％以下3X (l/[Cu]) + 2X [Ni] +0. 027X (l/[Cr]) +95X [Mo] +0. 00098X (l/[Sn]) +0. 0019X (1/([S b] + [W] ) ) -6. 5 • · · (3) Here, [c], [P], [S], [Cu], -14- 201042056 [Ni], [ The content (% by mass) of each of Cr], [Mo], [Sn], [31»], and ['^]. Further, the corrosion-resistant steel material for a crude oil oil tank of the present invention further contains Nb: 0.002 to 0.1% by mass, V: 0.002 to 0.1% by mass, Ti: 0.001 to 0.1% by mass, and Β: 〇·(in addition to the above-described component composition). Η Η Η 0.000 0.000 0.000 0.000 0.000 原油原油原油原油原油原油原油原油原油原油原油 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 In addition, in the corrosion-resistant steel material for crude oil oil tank of the present invention, the microstructure of the steel sheet having a thickness of 1/4 is contained in the range of 2 to 20% by area. In addition, the corrosion resistant steel material for the crude oil oil tank of the present invention is formed by forming a coating film containing a metal Zn or Zn compound on the surface of the steel material. Further, the corrosion resistant steel material for the crude oil oil tank of the present invention, wherein the coating film is Further, the Zn-containing tomb is l.g/m2 or more. Further, the present invention proposes a method for producing a corrosion-resistant steel material for a crude oil oil tank, which heats the steel material of the above composition to 1 000 to 1 3 50 ° After c, the post-calendering temperature is 75 ° ° C The upper portion is subjected to hot rolling, and is cooled to a cooling stop temperature of 650 ° C or lower and 450 ° C or higher at a cooling rate of 2 ° C /sec or more. The present invention is characterized by using a crude oil oil tank of the above steel material. Effect] -15- 201042056 According to the present invention, it is possible to inexpensively provide a steel which does not cause general corrosion or local corrosion in any part of a crude oil tank of an oil tank for a crude oil tanker or an oil tank for transporting or storing crude oil, [Embodiment] [Best Mode for Carrying Out the Invention] The following is a description of the reason why the component composition of the steel material for crude oil oil grooves of the present invention is limited to the above range. C: 0.00 1 ～0.16质量% c is an element which increases the strength of the steel. In the present invention, in order to obtain a desired strength ′, it is necessary to contain 0. 0.001% by mass or more. On the other hand, C not only causes corrosion resistance as the content increases. Deterioration, when added more than 〇. i 6 mass% 'will deteriorate the weldability and the roughness of the welded heat affected zone Therefore, C is in the range of 〇·〇〇1 to 0.16 mass%, and it is preferably from 0.01 to 〇.丨5 mass% from the viewpoint of improving strength and toughness. 〇1 to 0.15 mass% of the range is better. -16- 1 i : 1. 5 mass% or less

Si係作用爲脫酸劑（deoxidizing agent)，而同時也是使強度增加的兀素，添加超過1 . 1質量％時，會使鋼的韌性降低。因此，在本發明中，S i限定於1 · 1質量％以下 201042056 之範圍。此外，Si在酸性環境中，因會形成防蝕皮膜而致使耐蝕性向上提昇之故，若從改善酸性環境下的耐蝕性之觀點來看’係以添加0 · 2〜1 · 5質量％之範圍者爲佳， 0_3〜1.5質量％之範圍更佳。 Μη: 0_1 〜2.5 質量％ Μη係提高鋼材強度的元素，在本發明中，爲了獲得 0 所期望的強度，必須含有〇. 1質量％以上。另一方面，若添加超過2 · 5質量％，則在使鋼的朝性及熔接性降低的同時，會助長偏析（segregation)而導致鋼板組成的不均一化。因此，Μη設爲0.1〜2.5質量％之範圍。此外，從維持高強度，且抑制使耐蝕性劣化之夾雜物形成的觀點來看，係以0.5〜1·6質量％之範圍爲佳，0.8〜1.4質量％之範圍更佳。 Ο Ρ : 0.025質量％以下 Ρ係既會於粒界發生偏析而使鋼的韌性降低亦會使耐蝕性也降低的有害元素，其含量最好是盡可能地減低。特別是’若含有超過0.025質量％的話’在助長中央偏析（ central segregation )而導致鋼板組成的不均一化的同時，韌性亦會顯著地降低，故P設爲0.025質量％以下。此外，若P減低至小於0.003質量％的話，則因會導致製造成本大增之故，P的下限以0.003質量％程度爲佳’又，從使酸性環境（acid environment)中的耐全面腐触性向 -17- 201042056 上提昇之觀點來看，以設定在0·010質量％以下者爲再者，0.009質量％以下更佳。 S: 0.01質量％以下 S係會形成非金屬之夾雜物（non-metal incius彳 Μ n S而成爲腐蝕之起點且使耐局部腐蝕性及耐全面腐降低之有害元素，其含量最好是盡可能地減低。特別若含有超過〇 · 〇 1質量％，則因會導致耐局部腐鈾性全面腐蝕性的顯著降低，在本發明中，S的上限設爲質量％。此外，從使耐蝕性更加提昇之觀點來看， 0.0020質量％以下爲佳，但因極度地減低S會導致製本大增之故，實際上係0·0002〜0.0020質量％。再 0.0009質量％以下更佳。 Α1 : 0.005 〜0.1 質量％ Α1係作用爲脫酸劑之元素，在本發明中’必須 0.005質量％以上。另一方面，若添加超過〇·1質量則鋼的韌性會降低。因此，A1設爲0.0 0 5〜0 · 1質量範圍，較佳爲0.01〜質量％之範圍’又以〇·〇2〜質量％之範圍更佳。 Ν : 0.001 〜0.008 質量％ Ν爲使鋼的韌性向上提昇及熔接接頭部（weld part )之機械特性向上提昇，必須添加〇· 〇〇 1質量％佳。 on) 蝕性是，及耐 0.0 1 雖以造成者，含有 %， %之 0.04 joint 以上 18- 201042056 。但是，若添加超過0.008質量％，會導致固溶N之增加，依熔接條件，會使接頭部的韌性顯著地降低。因此，N 設爲 0.001〜0.008質量％之範圍，較佳爲 0.002〜0.005 質量％，更佳爲0.002〜0.004質量％之範圍。The Si function acts as a deoxidizing agent, and at the same time, it is a halogen which increases the strength. When the amount is more than 1.1% by mass, the toughness of the steel is lowered. Therefore, in the present invention, Si is limited to a range of 1.1% by mass or less and 201042056. In addition, in an acidic environment, since the corrosion resistance is increased by the formation of the anti-corrosion film, the range of addition of 0 · 2 to 1 · 5 mass % is considered from the viewpoint of improving the corrosion resistance in an acidic environment. Preferably, the range of 0_3 to 1.5% by mass is better. Μη: 0_1 ～2.5 mass % Μη is an element which increases the strength of the steel. In the present invention, in order to obtain a desired strength of 0, it is necessary to contain 〇. 1% by mass or more. On the other hand, when the addition is more than 25% by mass, the properties of the steel and the weldability are lowered, and segregation is promoted to cause unevenness in the composition of the steel sheet. Therefore, Μη is set in the range of 0.1 to 2.5% by mass. In addition, from the viewpoint of maintaining high strength and suppressing formation of inclusions which deteriorate corrosion resistance, it is preferably in the range of 0.5 to 1.6% by mass, and more preferably in the range of 0.8 to 1.4% by mass. Ο Ρ : 0.025 mass% or less The lanthanum is a harmful element that causes segregation at the grain boundary to lower the toughness of the steel and also lowers the corrosion resistance. The content of the lanthanide is preferably as low as possible. In particular, when the content is more than 0.025% by mass, the central segregation contributes to the non-uniformity of the steel sheet composition, and the toughness is remarkably lowered. Therefore, P is set to 0.025% by mass or less. In addition, if the P is reduced to less than 0.003 mass%, the manufacturing cost will increase greatly, and the lower limit of P is preferably about 0.003 mass%, and from the comprehensive corrosion resistance in the acid environment. From the viewpoint of the improvement of the -17-201042056, it is preferable to set it to 0. 010 mass% or less, and it is more preferably 0.009 mass% or less. S: 0.01% by mass or less S system forms non-metal inclusions (non-metal incius彳Μ n S, which is a starting point of corrosion and reduces the local corrosion resistance and overall rot resistance). In particular, if the content exceeds 1% by mass of 〇·〇, the overall corrosion resistance to local uranium resistance is significantly lowered. In the present invention, the upper limit of S is set to % by mass. From the viewpoint of further improvement, 0.0020% by mass or less is preferable, but the extremely low reduction of S causes a large increase in the cost, and is actually 0.0002 to 0.0020% by mass. More preferably 0.0009 mass% or less. Α1 : 0.005 ～0.1% by mass Α1 is an element which acts as a deacidifying agent, and is required to be 0.005 mass% or more in the present invention. On the other hand, if the mass exceeds 〇·1, the toughness of the steel is lowered. Therefore, A1 is set to 0.00. 5 to 0 · 1 mass range, preferably in the range of 0.01 to mass % 'more preferably in the range of 〇·〇 2 to mass %. Ν : 0.001 ～0.008 mass % ΝIn order to increase the toughness of the steel and weld the joint Weld part Mechanical properties upward, square-thousand and must add 1 mass% good. On) corrosion resistance, the resistance and 0.0 to 1, although those caused, percent or more,% of the 0.04 joint 18- 201042056. However, when the addition exceeds 0.008% by mass, the solid solution N increases, and the toughness of the joint portion is remarkably lowered depending on the welding conditions. Therefore, N is in the range of 0.001 to 0.008% by mass, preferably 0.002 to 0.005 mass%, more preferably 0.002 to 0.004 mass%.

Cu : 0.008 〜0.35 質量％ C u係有形成防蝕皮膜（a n t i c 〇 r r 〇 s i ο n c 〇 a t )而抑制 o 全面腐蝕之作用，在本發明中是必須添加之元素。但是，若少於0·008質量％，則未能獲得上述效果。另一方面， Cu會因與Sn進行複合添加而使耐全面腐蝕性顯著地提昇，但若添加超過0.35質量％的話，熱間加工性會降低，恐損害其製造性。因此，Cu設爲0.008〜0.35質量％之範圍。此外，Cu的添加效果係會因隨著添加量的增加而愈加飽和之故，從費用對效果之點來看，以0.0 0 8〜0 . 1 5質量％之範圍爲佳，0.01〜0.14質量％之範圍更佳。〇Cu : 0.008 to 0.35 mass % C u has an effect of forming an anti-corrosion film (a n t i c 〇 r r 〇 s i ο n c 〇 a t ) and suppressing o overall corrosion, and is an element which must be added in the present invention. However, if it is less than 0.008 mass%, the above effects are not obtained. On the other hand, Cu is remarkably improved by the addition of Sn, and the total corrosion resistance is remarkably improved. However, when it is added in an amount of more than 0.35% by mass, the hot workability is lowered, and the manufacturability is impaired. Therefore, Cu is set to a range of 0.008 to 0.35 mass%. In addition, the addition effect of Cu is more saturated with the increase of the amount of addition, from the point of view of cost to effect, it is preferably in the range of 0.08 to 0.15 mass%, preferably 0.01 to 0.14 mass. The range of % is better. 〇

Cr: 0.1質量％超0.5質量％以下Cr: 0.1% by mass or more and 0.5% by mass or less

Cr除了與CU —起於鋼材表面形成保護皮膜（ protective coating)，使酸性環境中的耐全面腐蝕性向上提昇之外，也有提高鋼材強度之作用，在本發明中是必須添加之元素。特別是，在含有硫酸離子及氯化物離子的酸性環境中，Cr會形成氧化皮膜（oxide layer )而覆蓋鋼材表面，有降低全面腐蝕速度之效果。又，Cr因會與Cu — 起令鏽層緻密化，即使在經富鋅底漆塗佈之狀態下，仍可 -19- 201042056 使Zn化合物長久停留在鏽層中之故，就算再包含塗裝後耐蝕性，仍對耐蝕性的向上提昇有極大的貢獻。再者’因可藉由Cr添加對耐蝕性向上提昇之效果來抑制Cu的添加量之故，係有減輕C u、S η共存下產生之熱間加工性降低的效果。但是，C r若添加0 · 1質量％以下時，並無法獲得上述的添加效果，另一方面，若添加超過〇.5質量％ ’則除了上述效果會飽和外，亦會導致成本的上昇及熔接性之劣化。因此，Cr係添加超過0.1質量％而於0.5質量％以下之範圍，較佳爲0.11〜0.3質量％之範圍，以0.12〜0.2 質量％之範圍又更佳。In addition to forming a protective coating on the surface of the steel material, the Cr enhances the overall corrosion resistance in an acidic environment, and also has an effect of increasing the strength of the steel. In the present invention, it is an element that must be added. In particular, in an acidic environment containing sulfate ions and chloride ions, Cr forms an oxide layer to cover the surface of the steel material, which has the effect of lowering the overall corrosion rate. In addition, Cr can be densified with Cu as a rust layer, even in the state of being coated with a zinc-rich primer, the Zn compound can remain in the rust layer for a long time, even if it is coated again. After the installation, the corrosion resistance still greatly contributes to the upward improvement of corrosion resistance. In addition, since the addition amount of Cu can be suppressed by the effect of increasing the corrosion resistance by the addition of Cr, the effect of reducing the inter-heat workability caused by the coexistence of Cu and S η is reduced. However, if C r is added in an amount of 0.1% by mass or less, the above-mentioned additive effect cannot be obtained. On the other hand, if the addition exceeds 0.5% by mass, the above effect will be saturated, and the cost will increase. Deterioration of weldability. Therefore, the Cr is added in an amount of more than 0.1% by mass and not more than 0.5% by mass, preferably in the range of 0.11 to 0.3% by mass, more preferably in the range of 0.12 to 0.2% by mass.

Sn : 0.005 〜0.3 質量％Sn : 0.005 ~ 0.3 mass %

Sn係藉由與Cu之複合效果，或是如後述在添加W 時藉由Cu及W之複合效果，除了會形成緻密的鏽層來抑制酸性環境下之全面腐蝕外，同時也有抑制局部腐蝕的作用，在本發明中是必須添加之元素。但是，若小於0.0 0 5 質量％ ’則無上述的添加效果，另一方面，若添加超過 0 · 3質量％，則會導致熱間加工性及韌性之劣化。因此， Sn設爲0.005〜0.3質量％之範圍，〇.〇2〜0.1質量％之範圍更佳，0.03〜0.09質量％之範圍又更佳。Sn is a composite effect with Cu, or a composite effect of Cu and W when W is added as described later, in addition to forming a dense rust layer to suppress overall corrosion in an acidic environment, and also suppressing local corrosion. The role is an element that must be added in the present invention. However, if it is less than 0.05% by mass, the above-mentioned addition effect is not obtained. On the other hand, when it is more than 0.03% by mass, deterioration of hot workability and toughness is caused. Therefore, Sn is in the range of 0.005 to 0.3% by mass, more preferably in the range of 〇. 2 to 0.1% by mass, and even more preferably in the range of 0.03 to 0.09% by mass.

Mo : 〇.〇1質量％以下Mo : 〇.〇1% by mass or less

Mo —般具有與W同樣的作用’且被認爲是使耐蝕性向上提昇之元素。但是’發明者們又新發現，相對於W -20- 201042056 在酸性鹽水環境下會形成不溶性之鹽，Mo在酸性鹽水環境下則會形成具溶解性之鹽，無法發揮阻隔效果，特別在 Mo含量超過0.01質量％而多量存在時，反而在酸性鹽水環境中之耐蝕性會劣化。因此，在本發明中係限制Μ 〇的含量在0.01質量％以下，較佳爲0.008質量％以下，更佳爲0.005質量％以下。以上元素係本發明之鋼材的基本成分。但是，本發明 0 之鋼材爲了兼具優異的耐全面腐蝕性及耐局部腐蝕性，不僅是使上述成分於上述組成範圍，更必須含有以下述（1 )式所定義之Α1的値爲0以下。甚至更佳爲Α1的値爲 -1以下。記 A1 = 28X [C] +2000Χ [Ρ] 2+27000Χ [S] 2+〇. 〇〇83 X (1/ [Cu] ) +0. 〇27X (l/[Cr]) +95X [Mo] +〇. 〇 0098X (l/[Sn]) -6 ...(1) Q 在此，上述式中之〔C〕、( P ] 、〔S〕、〔Cu〕、 [Cr ] 、〔Mo〕及〔Sn〕係各自之元素的含量（質量％ ) 上述（1 )式係一經驗式，表示包括了本發明中所實施之腐蝕試驗所得之涉及耐全面腐蝕性及耐局部腐蝕性的各元素之影響的耐蝕性指標之經驗式’已知’上述A 1的値若超過〇，則無法再確保耐全面腐蝕性及耐局部腐蝕性的任一者或雙方。此外，上述（〗）式中’有關各元素對耐蝕性之影響，1次及2次項的元素係表不愈是添加該元素其耐全面腐蝕性及耐局部腐蝕性愈是降低’另一方面， -21 - 201042056 呈反數之項的元素係表示愈是添加’其耐全面腐蝕性及耐局部腐飩性愈是提昇。也就是說，c及Μ 〇係耐蝕性降低元素、Ρ及S係以含量的2次方來影響之耐蝕性降低元素、Cu、Cr及Sn係耐蝕性提昇元素。本發明之鋼材除了上述基本成分外，係可進一步以下述之範圍添加N i。Mo generally has the same effect as W' and is considered to be an element that enhances corrosion resistance upward. However, the inventors have newly discovered that insoluble salt is formed in an acidic saline environment compared to W-20-201042056, and Mo forms a soluble salt in an acidic saline environment, which does not exert a barrier effect, especially in Mo. When the content exceeds 0.01% by mass and a large amount is present, the corrosion resistance in an acidic saline environment may deteriorate. Therefore, in the present invention, the content of the ruthenium is limited to 0.01% by mass or less, preferably 0.008% by mass or less, and more preferably 0.005% by mass or less. The above elements are essential components of the steel of the present invention. However, in order to achieve excellent corrosion resistance and local corrosion resistance, the steel material of the present invention has not only the above-mentioned components in the above-mentioned composition range, but also the enthalpy of Α1 defined by the following formula (1) is 0 or less. . Even better, the Α1 値 is -1 or less. A1 = 28X [C] +2000Χ [Ρ] 2+27000Χ [S] 2+〇. 〇〇83 X (1/ [Cu] ) +0. 〇27X (l/[Cr]) +95X [Mo] +〇. 〇0098X (l/[Sn]) -6 (1) Q Here, [C], (P], [S], [Cu], [Cr], [Mo] in the above formula And the content of each element of the [Sn] system (% by mass) The above formula (1) is an empirical formula indicating that the corrosion resistance test and the local corrosion resistance obtained by the corrosion test carried out in the present invention are included. The empirical formula of the corrosion resistance index of the influence of the element is 'known'. If the enthalpy of the above A 1 exceeds 〇, it is impossible to ensure either or both of the general corrosion resistance and the local corrosion resistance. In the 'related to the impact of various elements on the corrosion resistance, the elemental system of the 1st and 2nd term is not added, the addition of the element is more resistant to general corrosion and local corrosion resistance. On the other hand, -21 - 201042056 is reversed The element of the number of items indicates that the more it is added, the more it is resistant to general corrosion and local rot resistance. That is to say, the corrosion resistance of c and Μ 降低 is reduced by the elemental, Ρ and S series. Come to shadow The corrosion resistance of the ring is reduced by elements, Cu, Cr, and Sn. The steel of the present invention may further contain N i in addition to the above-described basic components.

Ni : 0.005 〜0.4 質量％Ni : 0.005 ~ 0.4 mass %

Ni係藉由與Cu複合來進行添加，而具有抑制熱間加工性之劣化的作用。但是，當添加小於0.005質量％時，無法獲得上述效果，另一方面，若添加超過〇 . 4質量％時，會導致成本上昇。因此，Ni係以添加0.005〜0.4質量 %之範圍爲佳。此外，從費用對效果之觀點來看，係以 0.005〜0_15質量％之範圍更佳，0.005〜0.1質量％之範圍又更佳。再者，若爲〇.〇3〜0.1質量％之範圍，又再更佳。此外，添加N i時，必須使以下述（2 )式所定義之 A2的値爲0以下來含有各成分以取代上述A1的値。甚至更佳爲A2的値爲-1以下。在此’由（2 )式可知，N丨係降低耐蝕性之元素。記 A2 = 28X [C] + 20〇〇χ [p] 2+27000X〔S] 2+0. 0083 X (l/[Cu]) + 2Χ [Ni] +〇, 〇27Χ (l/[Cr]) +95Χ [Mo] +0. 00098X (l/[Sn]) -6 ...(2) -22- 201042056 在此’上述式中之〔C〕、[ P ] 、〔S〕、〔Cu〕、〔Ni〕' ( Cr ) 、〔 Mo〕及〔Sn〕表示各自之元素的含量（質量％ )。又’本發明之鋼材除了上述成分之外，甚至能以下述之範圍添加Sb及W之中選出的1種或2種。Ni is added by compounding with Cu, and has an effect of suppressing deterioration of hot workability. However, when the addition is less than 0.005 mass%, the above effects are not obtained, and on the other hand, when the addition exceeds 0.4% by mass, the cost is increased. Therefore, Ni is preferably added in the range of 0.005 to 0.4% by mass. Further, from the viewpoint of cost and effect, the range is preferably 0.005 to 0_15% by mass, and the range of 0.005 to 0.1% by mass is more preferable. Furthermore, if it is in the range of 〜.〇3 to 0.1% by mass, it is even better. Further, when N i is added, it is necessary to contain 成分 of A2 defined by the following formula (2) to 0 or less, and to contain each component in place of hydrazine of the above A1. Even better, the A2 is less than -1. Here, it is known from the formula (2) that N丨 is an element which reduces corrosion resistance. A2 = 28X [C] + 20〇〇χ [p] 2+27000X[S] 2+0. 0083 X (l/[Cu]) + 2Χ [Ni] +〇, 〇27Χ (l/[Cr] ) +95Χ [Mo] +0. 00098X (l/[Sn]) -6 ...(2) -22- 201042056 Here [C], [P], [S], [Cu in the above formula ], [Ni]' (Cr), [Mo], and [Sn] represent the content (% by mass) of each element. Further, in addition to the above components, the steel material of the present invention can be added to one or two selected from the group consisting of Sb and W in the following range.

Sb: 0.005 〜0.3 質量％ ¢) Sb係與Sn同樣，藉由與Cu之複合效果，或是如後述在添加W時藉由Cu及W之複合效果，形成緻密的鏽層而具有抑制酸性環境中之腐蝕的作用，想提昇本特性時可進行添加。但是，若其添加小於0.005質量％則無效果，另一方面，若添加超過0.3質量％，則在效果飽和的同時，加工性也會降低。因此，添加Sb時，係以0.005〜〇.3質量％之範圍者爲佳，〇.〇2〜0.15質量％之範圍更佳，0.03〜0.09質量％之範圍又更佳。 ❹ W : 0.001 〜0.5 質量％ w係因腐蝕環境下所形成之wo42·離子在對氯化物離子等之陰離子（anion)發揮阻隔效果（barrier effect)的同時，形成不溶性（ins〇iubility)之FeW〇4而抑制腐鈾之進行。再者，也具有使鋼板表面所形成之鏽層緻密化的效果。而且，w因此等之化學的、物理的效果’而具有抑制在H2S及CΓ存在之腐蝕環境中的局部腐蝕及全面腐鈾之進行的效果。但是，若少於0 · 0 01質量％則無法獲得充 -23- 201042056 分的添加效果，另一方面，若添加超過0.5質量％，則不僅其效果會飽和，也會導致成本的上昇。因此，添加W 時’係以0.001〜〇_5質量％之範圍爲佳，0.02〜ο」質量 %之範圍更佳，0.03〜0.09質量％之範圍又更佳。此外’除上述N i之外，添加S b及/或w時，必須以下述（3 )式所定義之A3的値爲0以下來取代上述a i 或是A2的値，而含有各元素。甚至更佳爲A3的値爲-1 以下。在此’由（3 )式可知，Sb及W係使耐蝕性向上提昇之元素。記 A3 = 28X [C] +2 0 0 0 X [P] 2+ 2 7 0 0 0 X [S] 2+0, 008 3X (1/ [Cu]) +2X [Ni] +0. 027X (l/[Cr]) +95X [Mo] +0. 00098X (l/[Sn]) +0· 0019 (1/ ( [Sb] + [W] ) ) -6. 5 • · · (3) 在此，上述式中之〔C〕、〔P〕、[ S3 、〔Cu〕、〔Ni〕、〔Cr〕、〔Mo〕、〔Sn〕、〔Sb〕及〔W〕表示各自之元素的含量（質量％)。再者，本發明之鋼材爲了使強度及韌性向上提昇’除了上述成分外，係可進一步以下述之範圍添加Nb、V、Ti 及B之中選出的1種或2種以上。Sb: 0.005 to 0.3% by mass ¢) Sb-based, similar to Sn, forms a dense rust layer and has an acidic environment by a composite effect with Cu or a composite effect of Cu and W when W is added as described later. The effect of corrosion in the middle can be added when you want to improve this feature. However, if it is added in an amount of less than 0.005% by mass, the effect is not obtained. On the other hand, when the amount is more than 0.3% by mass, the workability is also lowered while the effect is saturated. Therefore, when Sb is added, it is preferably in the range of 0.005 to 〇.3 mass%, more preferably in the range of 〇. 2 to 0.15 mass%, and even more preferably in the range of 0.03 to 0.09 mass%. ❹ W : 0.001 to 0.5% by mass w The wo42 ion formed in a corrosive environment exhibits a barrier effect on anion such as chloride ions, and forms an insoluble (Insulubility) FeW. 〇4 inhibits the progress of uranium. Further, it has an effect of densifying the rust layer formed on the surface of the steel sheet. Moreover, w thus has a chemical and physical effect, and has the effect of suppressing local corrosion in the corrosive environment in which H2S and CΓ exist and overall uranium. However, if it is less than 0.001 mass%, the effect of adding -23-201042056 points cannot be obtained. On the other hand, if it is added more than 0.5 mass%, not only the effect will be saturated, but also the cost will increase. Therefore, when W is added, the range of 0.001 to 〇_5 mass% is preferable, the range of 0.02 to ο" mass% is more preferable, and the range of 0.03 to 0.09 mass% is more preferable. Further, when S b and/or w are added in addition to the above N i , it is necessary to replace the above-mentioned a i or A 2 以 with the 値 of A3 defined by the following formula (3), and to contain each element. Even better, the A3's 値 is -1 or less. Here, it can be seen from the formula (3) that Sb and W are elements which enhance the corrosion resistance upward. A3 = 28X [C] +2 0 0 0 X [P] 2+ 2 7 0 0 0 X [S] 2+0, 008 3X (1/ [Cu]) +2X [Ni] +0. 027X ( l/[Cr]) +95X [Mo] +0. 00098X (l/[Sn]) +0· 0019 (1/ ( [Sb] + [W] ) ) -6. 5 • · · (3) Therefore, [C], [P], [S3, [Cu], [Ni], [Cr], [Mo], [Sn], [Sb] and [W] in the above formula represent the content of each element. (quality%). In addition, in the steel material of the present invention, in addition to the above-mentioned components, one or two or more selected from the group consisting of Nb, V, Ti and B may be added in the following range.

Nb : 0.002 〜0.1 質量％Nb : 0.002 ~ 0.1 mass %

Nb係以鋼的強度及韌性向上提昇爲目的而添加之元 -24- 201042056 素。但是，若小於0.002質量％則無其效果，另一方面，若超過0.1質量％，則效果會飽和。因此，添加Nb時，係以0.002〜0.1質量％之範圍爲佳，0.004〜0.05質量％之範圍更佳，0.005〜0.01質量％之範圍又更佳。 V : 0.002 〜0· 1 質量％ V係以鋼的強度向上提昇爲目的而添加之元素。但是 ζ) ，若小於0.002質量％則沒有強度向上提昇之效果，另一方面，若添加超過0.1質量％則會導致韌性的降低。因此，添加時，係以0.002〜0.1質量％之範圍爲佳，0.003〜 0.05質量％之範圍更佳，0.004〜0.01質量％之範圍又更佳。Nb is added to the purpose of increasing the strength and toughness of steel. -24- 201042056. However, if it is less than 0.002 mass%, there is no effect. On the other hand, if it exceeds 0.1 mass%, the effect is saturated. Therefore, when Nb is added, it is preferably in the range of 0.002 to 0.1% by mass, more preferably in the range of 0.004 to 0.05% by mass, and still more preferably in the range of 0.005 to 0.01% by mass. V : 0.002 ～ 0· 1 Mass % V is an element added for the purpose of increasing the strength of steel. However, if it is less than 0.002% by mass, there is no effect of increasing the strength. On the other hand, if it is added in excess of 0.1% by mass, the toughness is lowered. Therefore, in the case of addition, it is preferably in the range of 0.002 to 0.1% by mass, more preferably in the range of 0.003 to 0.05% by mass, even more preferably in the range of 0.004 to 0.01% by mass.

Ti : 0.001 〜0· 1 質量％Ti : 0.001 ～0· 1 mass %

Ti係以鋼的強度及韌性向上提昇爲目的而添加之元〇素。但是，若小於o.ool質量％則無其效果，另一方面，若超過0.1質量％則效果會飽和。因此’添加時，係以 0.001〜0.1質量％之範圍爲佳，0.005〜0.03質量％之範圍更佳，0.006〜0.02質量％之範圍又更佳。 B: 0.01質量％以下 B係以鋼的強度向上提昇爲目的而添加之元素，其效果可藉由0.0003質量％以上的添加而得。但是，添加超過0.0 1質量％時，因爲會降低韌性，故添加時係以0 . 〇 i -25- 201042056 質量％以下爲佳’ 0.0003〜0.002質量％之範圍更佳， 0.0003〜0.0015質量％之範圍又更佳。再者，本發明之鋼材爲圖延展性及韌性之向上提昇，除了上述成分之外，係可進一步以下述之範圍添加Ca及 REM之中選出的1種或2種。Ti is a kind of element added for the purpose of increasing the strength and toughness of steel. However, if it is less than o.ool mass%, it has no effect. On the other hand, if it exceeds 0.1 mass%, the effect will be saturated. Therefore, the addition is preferably in the range of 0.001 to 0.1% by mass, more preferably 0.005 to 0.03% by mass, and even more preferably 0.006 to 0.02% by mass. B: 0.01% by mass or less B is an element added for the purpose of increasing the strength of the steel, and the effect can be obtained by adding 0.0003 mass% or more. However, when the addition exceeds 0.01% by mass, since the toughness is lowered, the addition is 0. 〇i -25 - 201042056% by mass or less is preferably in the range of 0.0003 to 0.002% by mass, and 0.0003 to 0.0015% by mass. The scope is even better. Further, the steel material of the present invention is improved in ductility and toughness, and one or two selected from the group consisting of Ca and REM may be further added in the following range in addition to the above components.

Ca ： 0.0002 〜0.005 質量％ C a係藉由夾雜物（i n c 1 u s i ο η )之形態控制（ morphological control)而具有使延展性（ductility)及韌性向上提昇之效果，同時，因具有使塗裝狀態中的耐蝕性向上提昇之效果，故可以此等之特性向上提昇爲目的來添加。但是，當添加小於0.0002質量％時，並無其效果，另一方面，若添加超過0.0 05質量％，則會導致韌性的降低。因此，添加時，係以0.0002〜0.005質量％之範圍爲佳，此外，從耐蝕性提昇之觀點來看，係以〇 . 0 〇 1〜 0.005質量％之範圍更佳，0.001〜0.003質量％之範圍又更佳。 REM: 0.0005 〜0.015 質量％ REM( Rare Earth Metal)意指原子序爲57〜71止之稀土類元素，一般而言，係可使用含有La ’ Ce，Pr，Nd 等之混合物米許合金（mischmetall )來進行添加。此 REM係控制夾雜物的形態而具有使延展性及韌性向上提昇之作用。但是，若小於0.0005質量％ ’未有其效果， -26- 201042056 另一方面’右添加超過〇. 〇 1 5質量％，則朝性會降低。因此’添加時’係以0.0005〜0.015質量％之範圍爲佳，此外’由使耐蝕性向上提昇之觀點來看，係以〇〇〇5〜〇.〇15 質量％之範圍更佳，0.00 5〜0.01質量％之範圍又更佳。此外，本發明之鋼材上述成分以外的殘餘部分，係由 Fe及不可避免之雜質所成。惟’本發明之鋼材若在無損及上述本發明之作用效果的範圍下，並不排除含有其他元 0 素，例如，若爲0則可含有〇 · 0 0 8 %以下。接著，係就本發明之原油油槽用鋼材的微細組織進行說明。本發明之鋼材，其位於板厚t之1 / 4位置之微細組織係由從肥粒鐵（ferrite )、波來鐵（pearlite )及變韌鐵變態（bainite transformation)所構成之複合組織所成，且含有以面積率計爲2〜20%之波來鐵者爲佳。一般而言，在控制具有相同成分組成之鋼強度的方法〇方面，雖使用有各種組織控制方法，但其中係以熱間壓延後的水冷（water cooling)爲最常用的方法之一。具有本發明之成分組成的鋼材，若於熱間壓延後進行緩慢冷卻（ s 1 〇 w c ο ο 1 i n g )的話，雖可形成由肥粒鐵與波來鐵所成的微細組織（microstructure) ’但若進行以水冷爲代表之急速冷卻處理，則上述波來鐵會變化成強度更高的變韌鐵組織。特別是，冷卻速度愈大，又’冷卻停止溫度（ cooling stop temperature)愈低’變韋刃鐵組織的比率愈商，最終會變成肥粒鐵與變韌鐵之2相組織。 -27- 201042056 但是’變韌鐵組織因係雪明碳鐵（c e m e n t i t e )之微小分散組織’而具有加速酸性環境（acid environment)中之腐鈾的性質。因此，使波來鐵組織殘存一定量而抑制雪明碳鐵之微細分散’係可提昇耐餓性。而明確地顯現因使波來鐵殘存所致之耐蝕性向上提昇效果的，係波來鐵之面積率爲2%以上。另一方面’若波來鐵組織的面積率超過 2 0 % ’則因韌性會降低而不佳。因此，本發明之鋼材中，爲了獲得更優異的耐蝕性，微細組織中之波來鐵的面積率係以控制在2〜20%之範圍爲佳。在此，令上述微細組織的測定位置爲鋼材之板厚1 /4的位置之理由係因，在如造船用之板厚的厚鋼材中，板厚1/ 4的位置係可代表全板厚，且因，鋼材的加工面即使暴露於腐餘環境中，從鋼材的表層至板厚中心部爲止，可滿足全面性耐全面腐餓性。此外，具有微細組織之本發明之原油油槽用耐蝕鋼材，大致上具有降伏應力爲315MPa以上、拉伸強度爲440MPa以上之強度。此外’若可得既定的強度，則變韌鐵組織即使不存在也無所謂。接著，就本發明之原油油槽用鋼材的製造方法進行說明。本發明之鋼材係可藉由使用將成分組成控制於上述本發明之範圍，而以與以往之鋼材同樣的方法進行製造。例如，以轉爐（steel converter)或電氣爐（electric furnace)、真空脫氣裝置（vacuum degassing equipment )等之2次精煉爐等，除了調節主要5元素之C、Si、Μη -28- 201042056 、P、S之外’亦調節Cu、Cr、Sn及Mo的含量至本發明之範圍’同時視其需要而添加其他合金元素，以溶製適合本發明之鋼。而後，將上述熔鋼以連續鑄造法或是造塊_ 分塊壓延法等製成鋼胚（steel slab )(鋼片），且將其鋼片直接或是冷卻後予以再加熱（reheat )來進行熱間壓延〇上述熱間壓延的條件，從確保耐蝕性及機械性特性（ ❹ mechanical properties)之觀點來看，有必要選擇適切的壓延溫度及壓下比且控制微細組織，具體而言，必須將具有經調整至上述適正範圍之成分組成的鋼素材加熱至 1 000 〜1 3 5 0°C 後，使壓延後製溫度（finishing temperature )爲75〇t以上進行熱間壓延，以2t/sec以上冷卻至 650°C以下、450°C以上之冷卻停止溫度爲止。鋼胚加熱溫度（slab heating temperature) : 1000〜 1 3 5 0¾ 〇加熱溫度若低於1 000°C則變形抗力會變大，熱間壓延困難。另一方面，若加熱超過1 3 50°c，則會成爲表面痕的發生原因，產能規模損失（scale loss )或燃料原單位（ fuel basic unit)會增加。較佳爲1100〜1300 °C之範圍。熱間壓延之後製溫度（hot roll finishing temperature ):7 5 0 °C 以上熱間壓延之後製溫度有必要爲750°C以上。若低於 750°C，則因鋼材到達既定的壓延溫度爲止之等待時間發生，而致Μ延能率（rolling efficiency )降低，或因變形 -29- 201042056 抗力（deformation resistance )增大而致壓延荷重（ rolling force)增加，難以進彳了壓延。熱間壓延後的冷卻速度：2°C /sec以上、冷卻停止溫度：6 5 0 °C以下、4 5 0 °C以上熱間壓延後的冷卻速度（cooling rate )有必要以 2 °C/sec以上進行冷卻。若小於2°C/sec，則肥粒鐵會粗大化且降伏應力會降低。另一方面，冷卻速度的上限並無特別限制，若爲一般水冷所得之80°C/sec程度以下即可。又，冷卻停止溫度有必要爲65 0°C以下、45(TC以上。若超過65 Ot，肥粒鐵會粗大化且降伏應力會降低，另一方面，若低於450 °C，則會導致波來鐵的分率小於2%。一般而言，油輪之原油油槽等中所用的鋼材，係使用有藉由塗佈含金屬Zn或是Zn化合物之底漆（primer )等之塗料（以下總稱爲「富鋅底漆（zinc primer)」）而使耐局部腐蝕性及耐全面腐蝕性向上提昇者。此等之鋼材係因在表面上實施珠擊除鏽處理（shotblasting)後而塗裝富鋅底漆之故’依鋼板的粗度等之表面狀態，會有無法完全覆蓋基底的情況’爲了完全覆蓋表面全體，必須要有一定量以上（例如，1 5 // m以上）的塗膜厚度。此點’在使用具有上述成分組成之鋼素材而以上述的方法所製造之本發明之原油油槽用鋼材，其特徵在於，不僅在無塗裝的狀態下具有優異的耐蝕性（耐全面腐蝕性、耐局部腐蝕性）’在塗裝後的耐蝕性上也很優異。特別是 ’本發明之原油油槽用鋼材係藉由使含有金屬Zn或是Zn -30- 201042056 化合物之底漆的塗佈量換算成Zn含量爲1.0g/m2以上，而得以使耐局部腐蝕性及耐全面腐蝕性更加地向上提昇。再者’若爲2.5 g/m2以上，則可獲得更加優異的耐局部腐蝕性及耐全面腐蝕性。此外，從耐局部腐蝕性及耐全面腐蝕性的觀點來看，雖未設定富鋅底漆塗佈量的上限，但若富鋅底漆之塗膜變厚，則因切斷性或熔接性會降低之故，上限的厚度宜以10〇Vm爲佳。富鋅底漆之塗膜厚（coating thickness )與鋼材表面之Zn含量的關係雖取決於富鋅底漆中之Zn含有率，但一般而言，若平均塗裝厚在15/zm以上，則得以覆蓋鋼材表面全體，且無須在意富鋅底漆之種類而得以確保換算成Zn含量爲1.0 g/m2以上之塗佈量。此外，鋼板表面之Zn含量係可藉由例如，由鋼材切出數個3 0mm平方的小片（例如，10個），完全溶解回收該表面之塗膜或鏽層，分析其中所含之Zn量而求得。〇 [實施例1] 將具有表1 -1〜表1 - 4中所示之成分組成的鋼，使用轉爐等予以熔製，以連續鑄造法製成厚度200tnm的鋼胚，將此等鋼胚加熱至12 00 °C後，進行後製壓延終了溫度爲 8 00°C之熱間壓延以壓延成板厚25mm，而後，以30°C/sec 之冷卻速度冷卻至580 °C爲止，製造出No.1〜35之鋼板。此外，就此等之鋼板觀察板厚1 /4位置中之微細組織，測定波來鐵的面積率，且確認了此等鋼板的全部，其微 -31 - 201042056 細組織中的波來鐵面積率爲2 %以上。又，就表1之N 〇.1及8的鋼’藉由使熱間壓延後的冷卻速度及冷卻停止溫度變化’來製造出微細組織中之波來鐵的面積率相異的鋼板。接著，使如上述般實施所得各鋼板之板厚1 /4的位置作爲被試驗面而取出長度50mmx寬幅50mmx厚度5mm之試驗片，且在其表面上實施珠擊除鏽後’製作成直接珠擊除鏽後之無塗裝狀態的試驗片、分別塗佈富鋅底漆的厚度爲5〜10"m、15〜25μτη及50〜70/zm之3種試驗片等合計具有4種表面狀態之腐蝕試驗片。而後，於該試驗片的5 0mm X 5 0mm之被試驗面上，留下局部腐蝕之起點的中央5πΐΓηφ之部分，均一地塗佈實際由油輪所取出之含原油成分的污泥。此外，Ζη的每單位面積之含量（塗佈量 )方面，若塗佈狀態均一，則與富鋅底漆的厚度呈比例，當富鋅底漆的厚度爲15μχη時，一般而言，不管富鋅底漆的種類爲何，均可確保換算成Ζιι塗佈量在1.0g/m2以上。接著，將上述試驗片供給圖1所示之構造的試驗裝置之試驗液中進行浸漬1個月之局部腐蝕試驗。此試驗裝置係由腐触試驗槽（corrosion test bath) 2與®溫槽（ constant-temperature bath) 3之雙重構造所構成者，於腐蝕試驗槽2中，注入可產生與在實際的原油油槽底板所生成之局部腐蝕同樣的局部腐蝕之試驗液6。此試驗液6係以含5 000質量ppm硫酸離子之1 〇質量％ NaCl水溶液 -32- 201042056 作爲母液，且使用在此母液中導入已調整至C02 : 13v〇l % + 〇2 : 5v〇I%〇2 + S〇2 : O.Olvol% + H2S : 0.3vol% 之濃度比的混合氣體（mixed gas ) 4並使其溶入之溶液。此外 ’上述混合氣體4的殘餘部分之調整氣體（adjustable gas )係爲惰性的N2氣體（inert nitrogen gas)。在上述試驗裝置中’爲了可連續供給混合氣體4，試驗液（test liquid ) 6要經常攪拌著。又，試驗液6之溫度係藉由置〇入恆溫槽3之水7的溫度來進行調整，保持在4〇r。上述腐蝕試驗終了後，去除試驗片之表面生成的鏽，在以目視觀察腐触形態（corrosion configuration)的同時 ’以深度計（d e p t h m e t e r )測定所發生之局部腐蝕的深度 ’且以下述之基準評價耐局部腐蝕性。 <耐局部腐蝕性的評價> AA(§):無局部腐蝕之發生 Ο A〇：局部腐鈾之深度小於〇.5mm ΒΔ.局部腐触之深度在0.5mm以上且小於lmm C X :局部腐蝕之深度爲1 mm以上將上述局部腐蝕試驗之結果顯示於表2及表3。由表 2可知，適合本發明之Ν ο · 1〜2 1的發明例之鋼板，不管有無富鋅底漆之塗佈，耐局部腐蝕性的評價皆顯示AA® 或A〇，即使是在無塗裝狀態下發生局部腐蝕時，其最大深度亦控制在小於〇_5mm，顯示出具有良好的耐局部腐蝕性。特別是，塗佈有1 5 /z m以上之富鋅底漆者，意即， -33- 201042056 富鋅底漆之塗佈狀態均一’且Zn含量爲1 ·0β/ηι2以上者，如No.3〜21皆爲AA◎，由此可確認’藉由富鋅底漆之塗佈，會使耐局部腐蝕性更進一步地向上提昇。另一方面’不滿足本發明之條件的比較例之No. 22〜 3 5的鋼板，意即’ C u、C r、S η的含量之至少一個低於本發明範圍者、P、S、Mo的含量超過本發明範圍者、或是任一耐蝕性之指標A 1〜A 3的値超過0之鋼板’不僅是未塗佈富鋅底漆的情況下’即使在塗佈的情況時’耐局部腐 11 蝕性的評價係爲CX或B △。意即’比較例之鋼板不僅是在無塗裝之狀態下的耐局部腐蝕性差，即使是在塗佈了富鋅底漆的情況下，耐局部腐蝕性也只是稍微提昇而已。又，表3係顯示出利用使微細組織中之波來鐵的面積率變化之鋼板，與上述同樣地實施，來評價無塗裝狀態中之耐局部腐蝕性的結果。由表3可知，相較於僅由不含波來鐵之變韌鐵所構成的微細組織之鋼板，可確認使波來鐵含有以面積率計爲2%以上之微細組織的鋼板係有耐局部 U 腐蝕性提昇之傾向。 [實施例2 ] 從實施例1所得之No . 1〜3 5的鋼板之板厚1 /4的位置’取出長度50mmx寬幅25mmx厚度4mm的矩形試驗片 ’在其表面實施珠擊除鏽後，與實施例1同樣地，製作出直接珠擊除鏽後之無塗裝狀態的試驗材、分別塗佈富鋅底漆的厚度（對Ζιι之每單位面積的含量呈比例）爲5〜i 〇 -34- 201042056 "m、15〜25ym及50〜70"m等3種程度之試驗片等合計具有4種表面狀態之腐蝕試驗片。此外’塗佈了富鋅底漆之試驗片中，爲了加速腐蝕，在被試驗面上實施深達鋼材表面之X字型的切割，以此爲模擬受損處。此外’此時之塗膜損傷以面積率計爲1.0%。接著，將上述試驗片供給使用可模擬原油油槽內之腐蝕環境之圖2所示試驗裝置的全面腐蝕試驗。此腐蝕試驗〇裝置係由腐蝕試驗槽1 2與溫度控制板1 3所構成’於腐蝕試驗槽12中，爲了保持飽和蒸氣壓，可注入水16，且溫度保持在30 °C。又，於腐蝕試驗槽的內部中，爲了模擬原油油槽內之腐蝕環境，係可在飽和水蒸氣壓（露點：3 0 °C )下充滿 C〇2: 13vol% ' 〇2 · 5vol% ' S〇2 · O.Olvol% ' H2S : 0.0 1 vol%、殘餘部分爲N2之混合氣體。將試驗片置於設置在上述腐蝕試驗槽上部之溫度控制板的下方，藉由加熱器與冷卻裝置，以25 °C XI小時/50 °C x5小時、昇溫〇、降溫時間：各1小時爲1個循環（8小時），連續進行 2 8日，係可模擬因凝結露水所致之全面腐蝕。此外，爲了在試驗片之表面（被試驗面）賦予硫酸離子及氯化物離子，係可塗佈相當於含有硫酸離子1 000質量ppm及氯化物離子1 0000質量ppm之混合了硫酸鈉及氯化鈉的水溶液5〇〇 V L且乾燥後，以供給於試驗。又，試驗開始後，係供給硫酸離子及氯化物離子一整週。上述腐蝕試驗終了後，就無塗裝狀態之試驗片，係於去除試驗片表面所生成之鏽後，由試驗前後的質量變化， -35- 201042056 求得因腐蝕所致的板厚減量，將此換算成每1年之腐蝕板厚，並以下述之基準評價耐全面腐蝕性。 <無塗裝材之耐全面腐飩性的評價〉 A〇：腐鈾速度小於0.2mm /年 ΒΛ :腐鈾速度爲0.2mm /年以上且小於〇.8mm /年 Cx:腐蝕速度爲〇.8mm/年以上又，就底漆塗佈材，測定在各試驗片之表面及塗膜下所產生出的鏽的面積率，且以下述之基準評價耐全面腐蝕性。 <底漆塗佈材之耐全面腐蝕性的評價> A〇：鏽面積率小於2 5 % ΒΔ :鏽面積率爲25%以上且小於50%Ca : 0.0002 to 0.005 mass % C a has an effect of improving ductility and toughness by morphological control of inclusions (inc 1 usi ο η ), and at the same time, has coating effect The corrosion resistance in the state is improved upwards, so it can be added for the purpose of improving the characteristics. However, when it is added in an amount of less than 0.0002% by mass, there is no effect. On the other hand, when it is added in an amount of more than 0.025% by mass, the toughness is lowered. Therefore, in the case of the addition, it is preferably in the range of 0.0002 to 0.005 mass%, and more preferably in the range of 〇. 0 〇1 to 0.005 mass%, and 0.001 to 0.003 mass% from the viewpoint of improvement in corrosion resistance. The scope is even better. REM: 0.0005 to 0.015% by mass REM (Rare Earth Metal) means a rare earth element having an atomic order of 57 to 71. In general, a mixture containing La ' Ce, Pr, Nd, etc. (mischmetall) can be used. ) to add. This REM controls the morphology of the inclusions and has the effect of increasing the ductility and toughness. However, if it is less than 0.0005 mass% ‘there is no effect, -26- 201042056 on the other hand, when the right addition exceeds 〇. 〇 15 mass%, the orientation will decrease. Therefore, the 'additional time' is preferably in the range of 0.0005 to 0.015 mass%, and in addition, from the viewpoint of improving the corrosion resistance, the range of 〇〇〇5 to 〇.〇15% by mass is more preferable, 0.00 5 The range of ~0.01% by mass is even better. Further, the remainder of the steel material of the present invention other than the above components is formed of Fe and unavoidable impurities. However, the steel material of the present invention does not exclude the inclusion of other elements in the range of the non-destructive effects and the effects of the present invention described above. For example, if it is 0, it may contain 〇 · 0 0 8 % or less. Next, the microstructure of the steel material for a crude oil tank of the present invention will be described. The steel material of the present invention is formed by a composite structure composed of ferrite, pearlite and bainite transformation at a position of 1 / 4 of the thickness t. It is preferable to contain a wave of iron in an area ratio of 2 to 20%. In general, in the method of controlling the strength of steel having the same composition, 各种 various structural control methods are used, but among them, water cooling after hot rolling is one of the most commonly used methods. A steel material having the composition of the present invention can be formed into a microstructure (fertilized by ferrite iron and ferrite) if it is slowly cooled (s 1 〇wc ο ο 1 ing ) after rolling between heats. However, if the rapid cooling treatment represented by water cooling is performed, the above-mentioned wave iron will be changed into a toughened iron structure having a higher strength. In particular, the larger the cooling rate, the lower the 'cooling stop temperature', the higher the ratio of the iron structure to the web, and eventually the two-phase structure of the ferrite iron and the toughened iron. -27- 201042056 However, the 'toughened iron structure' has the property of accelerating uranium in the acid environment due to the small dispersed structure of the celestial carbon iron (c e m e n t i t e). Therefore, it is possible to improve the tolerance to starvation by allowing a certain amount of the Borne iron structure to remain and suppressing the fine dispersion of the ferritic carbon. However, it is clear that the surface area of the Borne iron is 2% or more because the corrosion resistance caused by the residual iron is increased upward. On the other hand, if the area ratio of the Borne iron structure exceeds 20%, the toughness will be lowered. Therefore, in the steel material of the present invention, in order to obtain more excellent corrosion resistance, the area ratio of the ferrite in the fine structure is preferably controlled in the range of 2 to 20%. Here, the reason why the measurement position of the fine structure is a position of 1/4 of the thickness of the steel material is that, in a thick steel material such as a shipbuilding thickness, the position of the plate thickness of 1/4 can represent the full thickness. Moreover, even if the machined surface of the steel is exposed to the corrosive environment, it can satisfy the comprehensive resistance to full hunger from the surface layer of the steel to the center of the plate thickness. Further, the corrosion-resistant steel material for a crude oil oil tank of the present invention having a fine structure has a tensile stress of 315 MPa or more and a tensile strength of 440 MPa or more. In addition, if a given strength is obtained, the toughened iron structure does not matter if it does not exist. Next, a method for producing a steel material for a crude oil sump according to the present invention will be described. The steel material of the present invention can be produced by the same method as the conventional steel material by controlling the component composition to the above-described range of the present invention. For example, a secondary refining furnace such as a steel converter, an electric furnace, or a vacuum degassing equipment, in addition to adjusting the main five elements of C, Si, Μ -28 - 201042056, P Further, the contents of Cu, Cr, Sn, and Mo are adjusted to the range of the present invention, and other alloying elements are added as needed to dissolve the steel suitable for the present invention. Then, the molten steel is made into a steel slab (steel sheet) by a continuous casting method or a block-blocking method, and the steel sheet is reheated directly or after cooling. In order to ensure the corrosion resistance and the mechanical properties (❹ mechanical properties), it is necessary to select a suitable rolling temperature and a reduction ratio and control the fine structure, specifically, The steel material having the composition adjusted to the above-mentioned proper range must be heated to 1 000 to 1 350 ° C, and the finishing temperature is 75 〇t or more for inter-heat rolling, to 2 t / The temperature is sec or more and is cooled to 650 ° C or lower and 450 ° C or higher. Slab heating temperature: 1000~ 1 3 5 03⁄4 〇 If the heating temperature is lower than 1 000 °C, the deformation resistance will become large and the inter-heat rolling will be difficult. On the other hand, if the heating exceeds 1 3 50 °c, it will cause the occurrence of surface marks, and the scale loss or the fuel basic unit will increase. It is preferably in the range of 1100 to 1300 °C. Hot hot finishing temperature: 7 5 0 °C or more After the hot rolling, the temperature is necessary to be 750 ° C or more. If it is lower than 750 ° C, the waiting time for the steel material to reach the predetermined rolling temperature occurs, and the rolling efficiency is lowered, or the deformation load is increased due to the deformation resistance -29- 201042056. (The rolling force) increases, making it difficult to advance the rolling. Cooling rate after hot rolling: 2 ° C / sec or more, cooling stop temperature: 650 ° C or less, cooling rate after cooling between 4500 ° C or more is necessary to be 2 ° C / Cool down above sec. If it is less than 2 ° C / sec, the ferrite iron will coarsen and the stress will decrease. On the other hand, the upper limit of the cooling rate is not particularly limited, and may be 80 ° C / sec or less which is generally obtained by water cooling. Further, the cooling stop temperature is required to be 65 ° C or less and 45 (TC or more. If it exceeds 65 Ot, the ferrite iron will be coarsened and the stress will be lowered. On the other hand, if it is lower than 450 ° C, it will result in The fraction of the Borne iron is less than 2%. In general, the steel used in the oil tank of the oil tanker or the like is a coating material by applying a primer containing a metal Zn or a Zn compound (hereinafter referred to as a general term). For the "zinc primer", the local corrosion resistance and general corrosion resistance are improved upwards. These steels are coated with rich shots after being subjected to shot blasting on the surface. The reason for the zinc primer is that depending on the surface state such as the thickness of the steel sheet, there is a case where the substrate cannot be completely covered. In order to completely cover the entire surface, it is necessary to have a coating thickness of a certain amount or more (for example, 1 5 // m or more). The steel material for a crude oil sump of the present invention produced by the above method using a steel material having the above-described composition is characterized in that it has excellent corrosion resistance (corrosion resistance) not only in a non-coated state. Sexuality The corrosion resistance of the part is also excellent in the corrosion resistance after coating. In particular, the steel material for the crude oil sump of the present invention is converted by the coating amount of the primer containing the metal Zn or the Zn -30- 201042056 compound. The Zn content is 1.0 g/m2 or more, and the local corrosion resistance and the general corrosion resistance are further improved. Further, if it is 2.5 g/m2 or more, more excellent local corrosion resistance and resistance can be obtained. In addition, from the viewpoint of local corrosion resistance and general corrosion resistance, although the upper limit of the coating amount of the zinc-rich primer is not set, if the coating film of the zinc-rich primer becomes thick, the cutting is caused by the cutting. If the properties or weldability are lowered, the upper limit should preferably be 10 〇Vm. The relationship between the coating thickness of the zinc-rich primer and the Zn content of the steel surface depends on the Zn in the zinc-rich primer. In general, if the average coating thickness is 15/zm or more, it is possible to cover the entire surface of the steel material, and it is not necessary to care about the type of the zinc-rich primer to ensure that the conversion to the Zn content is 1.0 g/m2 or more. In addition, the Zn content of the surface of the steel sheet can be For example, several pieces of 30 mm square pieces (for example, 10 pieces) are cut out from the steel material, and the coating film or the rust layer of the surface is completely dissolved and analyzed, and the amount of Zn contained therein is analyzed to obtain the 。 [Example 1] The steel having the composition shown in Table 1-1 to Table 1-4 is melted using a converter or the like, and a steel preform having a thickness of 200 tnm is formed by a continuous casting method, and the steel embryos are heated to 1,200 ° C. After the calendering, the temperature was changed to a temperature of 800 ° C to be rolled to a thickness of 25 mm, and then cooled to 580 ° C at a cooling rate of 30 ° C / sec to produce a steel sheet No. 1 to 35. . In addition, the area ratio of the ferritic iron was measured in the fine structure at the position of the steel plate observation plate at a position of 1/4, and the area ratio of the ferritic iron in the fine structure of the micro-31 - 201042056 was confirmed. It is more than 2%. Further, in the steels of N 〇.1 and 8 of Table 1, the steel sheets having different area ratios of the ferrite in the fine structure were produced by changing the cooling rate and the cooling stop temperature after the heat is rolled. Then, a test piece having a length of 50 mm x a width of 50 mm x a thickness of 5 mm was taken out as a test surface by using a position of 1 / 4 of the thickness of each of the obtained steel sheets as described above, and the surface was subjected to bead blasting and rusting. The test piece in the uncoated state after the bead blasting, and the three kinds of test pieces each having a zinc-rich primer having a thickness of 5 to 10 "m, 15 to 25 μτη, and 50 to 70/zm, respectively, have four kinds of surfaces. State corrosion test piece. Then, on the test surface of the test piece of 50 mm X 50 mm, the portion of the center 5πΐΓηφ of the starting point of local corrosion was left, and the sludge containing the crude oil component actually taken out by the tanker was uniformly applied. Further, in terms of the content per unit area (coating amount) of Ζη, if the coating state is uniform, it is proportional to the thickness of the zinc-rich primer, and when the thickness of the zinc-rich primer is 15 μχ, generally, regardless of the rich The type of zinc primer can be ensured to be converted to Ζιι coating amount of 1.0g/m2 or more. Next, the test piece was supplied to the test liquid of the test apparatus of the structure shown in Fig. 1 and subjected to a partial corrosion test for one month. The test device is composed of a double structure of a corrosion test bath 2 and a constant-temperature bath 3. In the corrosion test tank 2, the injection can be generated with the actual crude oil tank bottom plate. The resulting test solution 6 which locally corrodes the same localized corrosion. This test solution 6 is a mother liquor containing 1 质量 mass% NaCl solution -32- 201042056 containing 5,000 ppm by mass of sulfate ions, and the introduction into the mother liquor has been adjusted to C02 : 13v〇l % + 〇2 : 5v〇I %〇2 + S〇2 : O.Olvol% + H2S : 0.3 vol% of a mixed gas (mixed gas) 4 and dissolved therein. Further, the "adjustable gas" of the remaining portion of the mixed gas 4 is an inert nitrogen gas. In the above test apparatus, in order to continuously supply the mixed gas 4, the test liquid 6 is constantly stirred. Further, the temperature of the test liquid 6 was adjusted by the temperature of the water 7 placed in the constant temperature bath 3, and was maintained at 4 Torr. After the end of the above corrosion test, the rust generated on the surface of the test piece was removed, and the depth of local corrosion generated by the depth meter was measured while visually observing the corrosion configuration and evaluated on the basis of the following criteria. Resistant to local corrosiveness. <Evaluation of local corrosion resistance> AA(§): No local corrosion occurred Ο A〇: The depth of local uranium is less than 〇.5 mm ΒΔ. The depth of local rot is 0.5 mm or more and less than 1 mm CX : Partial The corrosion depth was 1 mm or more. The results of the above partial corrosion test are shown in Tables 2 and 3. As can be seen from Table 2, the steel sheets of the invention examples suitable for the present invention are coated with a zinc-rich primer, and the evaluation of local corrosion resistance shows AA® or A〇, even in the absence of When local corrosion occurs in the coating state, the maximum depth is also controlled to be less than 〇5 mm, showing good local corrosion resistance. In particular, those coated with a zinc-rich primer of 1 5 /zm or more, that is, -33- 201042056 zinc-rich primer has a uniform coating state and a Zn content of 1 · 0 β / ηι 2 or more, such as No. 3 to 21 are all AA ◎, and it can be confirmed that the coating by the zinc-rich primer causes the local corrosion resistance to be further increased upward. On the other hand, the steel sheet of No. 22 to 35 which is a comparative example which does not satisfy the conditions of the present invention means that at least one of the contents of 'C u, C r and S η is lower than the range of the present invention, P, S, A steel sheet having a Mo content exceeding the range of the present invention or any of the corrosion resistance indexes A 1 to A 3 exceeding 0 is not only in the case where the zinc-rich primer is not coated, even in the case of coating. The evaluation of resistance to local corrosion is CX or B △. This means that the steel sheet of the comparative example is not only poor in local corrosion resistance in the uncoated state, but even in the case where a zinc-rich primer is applied, the local corrosion resistance is only slightly improved. In addition, Table 3 shows a steel sheet which was changed in the area ratio of the iron in the fine structure, and was evaluated in the same manner as above to evaluate the local corrosion resistance in the uncoated state. As can be seen from Table 3, it is confirmed that the steel sheet having a fine structure of 2% or more in area ratio is resistant to the steel sheet having a fine structure composed of the toughened iron containing no iron. The tendency of local U to increase corrosiveness. [Example 2] No. 1 to 3 5 of the steel sheet obtained in Example 1 was taken at a position of 1/4 of the thickness of the steel sheet of '50 mm x width 25 mm x thickness 4 mm' after the surface was subjected to bead blasting. In the same manner as in the first embodiment, the test material in the uncoated state after direct bead blasting was produced, and the thickness of each of the zinc-rich primers (the ratio of the area per unit area of Ζιι) was 5 to i.腐蚀-34- 201042056 "m, 15~25ym and 50~70"m and other test pieces, etc., have a total of four kinds of surface state corrosion test pieces. Further, in the test piece coated with the zinc-rich primer, in order to accelerate the corrosion, an X-shaped cut of the surface of the steel material was carried out on the surface to be tested, thereby simulating the damaged portion. Further, the film damage at this time was 1.0% in terms of area ratio. Next, the test piece was supplied to a comprehensive corrosion test using the test apparatus shown in Fig. 2 which simulates the corrosive environment in the crude oil tank. This corrosion test apparatus is composed of a corrosion test tank 12 and a temperature control plate 13 in the corrosion test tank 12, and in order to maintain a saturated vapor pressure, water 16 can be injected and the temperature is maintained at 30 °C. In addition, in the interior of the corrosion test tank, in order to simulate the corrosion environment in the crude oil tank, the saturated water vapor pressure (dew point: 30 ° C) can be filled with C〇2: 13vol% ' 〇 2 · 5vol% ' S 〇2 · O.Olvol% 'H2S : 0.0 1 vol%, and the residual part is a mixed gas of N2. The test piece is placed under the temperature control plate disposed above the corrosion test tank, and is heated by a heater and a cooling device at 25 ° C for XI hours / 50 ° C for 5 hours, and the temperature is lowered and the cooling time is 1 hour. One cycle (8 hours), continuous for 28 days, can simulate the overall corrosion caused by condensation dew. In addition, in order to impart sulfate ions and chloride ions to the surface (test surface) of the test piece, it is possible to apply a mixture of sodium sulfate and chlorinated in an amount equivalent to 1 000 ppm by mass of sulfate ions and 1,000,000 ppm by mass of chloride ions. The sodium aqueous solution was 5 〇〇 VL and dried to be supplied to the test. Further, after the start of the test, sulfate ions and chloride ions were supplied for a whole week. After the end of the above corrosion test, the test piece without the coating state is obtained by removing the rust generated on the surface of the test piece and determining the thickness reduction due to corrosion from -35 to 201042056. This was converted into a corrosion plate thickness per one year, and the general corrosion resistance was evaluated on the basis of the following criteria. <Evaluation of full rot resistance of uncoated materials> A〇: uranium speed is less than 0.2mm / year ΒΛ: uranium speed is 0.2mm / year and less than 〇.8mm / year Cx: corrosion rate is 〇 Further, in the primer coating material, the area ratio of the rust generated on the surface of each test piece and the coating film was measured, and the general corrosion resistance was evaluated on the basis of the following criteria. <Evaluation of general corrosion resistance of primer coating material> A〇: rust area ratio is less than 25% ΒΔ: rust area ratio is 25% or more and less than 50%

Cx:鏽面積率爲50%以上上述全面腐蝕試驗的結果係顯示於表4及表5。由表 4可知，適合本發明之No. 1〜2 1的發明例之鋼板，在無塗裝材之耐全面腐蝕性的評價皆爲A〇，在良好的同時，塗佈了富鋅底漆之耐全面腐鈾性亦全爲A〇，意即，可確認發明例之鋼板，不僅在無塗裝狀態下具有良好的耐全面腐蝕性，更可藉由富鋅底漆塗佈，而更進一步地具有良好的耐全面腐蝕性。另一方面，比較例之鋼板No. 22〜35不僅在未塗佈有富鋅底漆的情況下，即使於塗佈時，耐全面腐蝕性的評儐 -36 - 201042056 也僅爲c X或B△’可知在任一情況下，其耐全面腐蝕性都差。又’表5係顯示出使用實施例丨中所得使微細組織中之波來鐵的面積率變化的鋼板，來進行無塗裝狀態中之全面腐蝕試驗’且以與上述同樣之基準評價耐全面腐飩性之結果者。由表5可知，波來鐵的面積率爲2%以上之鋼板係與耐局部腐蝕性同樣地，亦具有耐全面腐蝕性提昇之傾〇向。 [產業上的可利用性] 本發明之技術並不限於原油油輪之油槽或輸送或貯藏原油用之油槽等的原油油槽用鋼材，對於在類似的腐蝕環境下所使用的其他領域之鋼材，包含倂用底漆塗裝或是一般塗裝的情況也相當適用。 ❹ -37- 201042056 【1-1 ®Cx: rust area ratio of 50% or more The results of the above general corrosion test are shown in Tables 4 and 5. As can be seen from Table 4, the steel sheets of the invention examples of Nos. 1 to 2 1 which are suitable for the present invention are evaluated as A〇 in the general corrosion resistance of the non-coated materials, and coated with a zinc-rich primer at the same time. The full-resistance uranium resistance is also A 〇, which means that the steel sheet of the invention can be confirmed not only in the non-coating state, but also in the general corrosion resistance, and can be coated by the zinc-rich primer. It has further good general corrosion resistance. On the other hand, in the steel sheets No. 22 to 35 of the comparative example, not only when the zinc-rich primer was not applied, but also when the coating was applied, the evaluation of the general corrosion resistance was only c X or B△' shows that in either case, its resistance to general corrosion is poor. Further, 'Table 5 shows that the steel sheet obtained by changing the area ratio of the ferrite in the fine structure obtained in the Example 来 was subjected to the general corrosion test in the uncoated state' and evaluated comprehensively on the same basis as above. The result of the rot. As is clear from Table 5, the steel sheet having an area ratio of 2% or more of the ferrite is similar to the local corrosion resistance, and has a tendency to improve the overall corrosion resistance. [Industrial Applicability] The technology of the present invention is not limited to oil tanks for crude oil tankers or steel oil tanks for oil tanks for transporting or storing crude oil, and includes steels for other fields used in a similar corrosive environment. The use of primer or general coating is also quite applicable. ❹ -37- 201042056 [1-1 ®

I-I* 備註發明例1 發明例丨發明例1 發明例1 發明例1 發明例I 發明例I 發明例1 發明例1 發明例1 發明例1 發明例1 發明例1 發明例I 發明例1 發明例1 發明例丨發明例1 化學成分(質量％) (接續後頁） 1 1 1 I f 1 t 1 1 1 1 1 ! 1 .1 1 1 0.035 0. 032 0·029 0-032 0.043 | 0. 033 0.025 0. 021 0-036 0. 031 0. 030 0,032 0,028 0. 029 0. 028 0.037 0.032 0- 030 ώ d CO Ο 卜 1 < ο CO d σ> ο i-H f·^ 〇 τΉ d *-H d CO t-H o 2 d o LA d 0.15 d CD 〇 o o 寸 d 0.067 0.089 0.086 0. 077 0. 091 CD g 〇 0.012 0. 081 0. 054 0,075 0,082 0.010 0. 120 0. 029 0.057 0.009 0.140 0. 092 0. 0023 0. 0019 0.0022 0. 0024 0, 0022 1 0. 0026 0. 0034 0. 0024 0.0026 0. 0026 ΞΞ 0. 0030 0. 0026 0. 0026 0.0032 0.0031 0. 0029 sol· Α1 丨 0. 032 0. 035 0,032 0-029 0.033 1 0. 033 0. 037 0.033 0. 031 0. 036 0-037 0-035 0. 034 0. 035 0. 035 0. 036 0. 031 0. 036 cc 0. 0019 0.0016 0. 0015 0. 0016 0. 0010 0. 0014 0.0013 0.0016 0. 0016 0.0012 BBS Ξ 0. 0018 0. 0008 0. 0009 0. 0009 α. 0.009 0.017 0. 012 0. Oil 0.017 1 0.008 0. 008 0. 009 0. 010 0.010 0,012 0.007 0. 007 0.008 0. 006 0,007 0. 006 0. 006 9 ο A — σ» S PO cc T—< 0. 99 o o rH Oi CO 二 o i-H in 寸 T~< 0. 96 0. 96 00 CO tH 0. 95 w 0. 32 0.35 0·25 CD d o 0.33 0. 34 0.40 CO o d 0. 33 0. 33 0. 32 0. 34 0.31 0. 36 0. 25 0. 35 U 0.06 1 ο 0. 05 CO d 0.07 o Ln d 0.14 0. 06 0. 06 0. 06 g o 3 d g o LA 0 d 0- 06 o 鋼板 No CO 寸 CO 卜 00 〇a o CO 寸 rH LA CO QO -38 - 201042056 [表 1-2]II* Remarks Inventive Example 1 Inventive Example 1 Inventive Example 1 Inventive Example 1 Inventive Example I Inventive Example 1 Inventive Example 1 Inventive Example 1 Inventive Example 1 Inventive Example 1 Inventive Example 1 Inventive Example 1 Inventive Example 1 Inventive Example 丨 Inventive Example 1 Chemical composition (% by mass) (Continued on the following page) 1 1 1 I f 1 t 1 1 1 1 1 ! 1 .1 1 1 0.035 0. 032 0·029 0-032 0.043 | 033 0.025 0. 021 0-036 0. 031 0. 030 0,032 0,028 0. 029 0. 028 0.037 0.032 0- 030 ώ d CO Ο 卜 1 < ο CO d σ> ο iH f·^ 〇τΉ d *- H d CO tH o 2 do LA d 0.15 d CD 〇oo inch d 0.067 0.089 0.086 0. 077 0. 091 CD g 〇0.012 0. 081 0. 054 0,075 0,082 0.010 0. 120 0. 029 0.057 0.009 0.140 0. 092 0. 0023 0. 0019 0.0022 0. 0024 0, 0022 1 0. 0026 0. 0034 0. 0024 0.0026 0. 0026 ΞΞ 0. 0030 0. 0026 0. 0026 0.0032 0.0031 0. 0029 sol· Α1 丨0. 032 0 035 0,032 0-029 0.033 1 0. 033 0. 037 0.033 0. 031 0. 036 0-037 0-035 0. 034 0. 035 0. 035 0. 036 0. 031 0. 036 cc 0. 0019 0.0016 0. 0015 0. 0016 0. 0010 0. 0014 0.0013 0.0016 0. 0016 0.0012 BBS Ξ 0. 0018 0. 0008 0. 0009 0. 0009 α. 0.009 0.017 0. 012 0. Oil 0.017 1 0.008 0. 008 0. 009 0. 010 0.010 0,012 0.007 0. 007 0.008 0. 006 0,007 0. 006 0 006 9 ο A — σ» S PO cc T—< 0. 99 oo rH Oi CO Two o iH in inches T~< 0. 96 0. 96 00 CO tH 0. 95 w 0. 32 0.35 0· 25 CD do 0.33 0. 34 0.40 CO od 0. 33 0. 33 0. 32 0. 34 0.31 0. 36 0. 25 0. 35 U 0.06 1 ο 0. 05 CO d 0.07 o Ln d 0.14 0. 06 0 06 0. 06 go 3 dgo LA 0 d 0- 06 o Steel plate No CO inch CO 00 〇ao CO inch rH LA CO QO -38 - 201042056 [Table 1-2]

表1-2 鋼板 (接續前頁）化學成分(質量％) 耐蝕性之指標値 No Ni Sb W Nb、V、 Ti、B Ca 'REM A1 A2 A3 備註 1 - - - 一 - -3.7 — - 發明例 2 - - - - -LI - - 發明例 3 0.092 一 - - - - -3.8 發明例 4 0.049 0.06 - - — - - -2.1 發明例 5 0.089 - 0.05 一 - - - - 3· 5 發明例 6 0. 082 0.06 0.06 - - - - -1.8 發明例 7 - 0. 05 - - - - ~1. 2 發明例 8 - - 0. 08 - - - - -1.9 發明例 9 0.06 0. 07 - - - - 41 發明例 10 0,034 0.06 0. 07 Nb：0.012 - - - -4.1 發明例 11 - 0.11 0.08 Nb:0.007、 V :0,004 - - -4,1 發明例 12 - 0.04 0.10 V :0.006, Ti:0,012 — - - ~3.6 發明例 13 - 0.04 0.05 Nb:0.008、 Ti :0.010 - - - -2-1 發明例 14 0. 053 0.10 0. 04 Ti :0.013 , B :〇_〇〇〇9 - - - -4.0 發明例 15 - 0.06 0. 05 B :0. 0011 - - - -1·8 發明例 16 - 0.07 0. 06 - Ca :0.0020 - - -1.4 發明例 17 0·068 0. 05 0.06 Ca :0. 0023 - - -4.3 發明例 18 0. 001 0.05 0.06 Nb :0.008 Ca :0, 0022 - - -2.2 發明例 -39- 201042056 備註發明例I 發明例I 發明例1 比較例I 比較例1 比較例1 比較例1 比較例1 u 比較例丨比較例1 比較例比較例1 比較例1 比較例1 比較例1 (接續後頁） ] 1 [ 1 \ 1 1 I ί 」 1 1 1 1 l 0.05 0- 06 I i _1 1 0. 031 0. 036 0.037 0. 001 0. 042 0. 001 0.035 0. 001 0.026 0.037 c>a S C5 0.032 0.001 1 0,036 0. 049 0.033 0. 028 U CO ifH 〇· 寸 y—i Ο 卜 1—1 d 5l CO b CO o CO o 0. 15 0-05 0-21 〇 r-^ — d τΗ Ο 3 o ΙΟ o o CO ο β 0.086 0.093 0,052 s o c5丨 0. 030 0.081 (N 〇 o o 0.009 0.006 0.007 0.003 0. 100 0.066 0.043 0.069 0-086 _ 腾 ζ 0-0023 0. 0025 0-0027 0.0036 0. 0022 0. 0024 0, 0024 0. 0025 0, 0028 0.003 0. 0031 0.0029 0. 0025 0-0026 0-0028 0. 0022 0. 0029 soLAl 0.031 0. 031 0. 036 0.035 0.036 0.033 0.036 0.031 0.033 0. 035 0. 031 0.032 0.034 0.034 0. 035 0. 034 0. 036 ω 0. 0008 0. 0007 0. 0006 _ i B 0-0017 0-0019 0. 0008 0. 0007 0. 0016 0. 0013 0. 0013 0. 0006 0, 0009 0. 0120 0. 007 0.007 0.007 0.018 0.022 0-009 0.010 0.007 0.018 0. 007 0. 008 0.009 0.020 0.006 0. 008 0. 026 0. 012 τΗ rA Ο rH LA v-H i-J CO CC l-H 0.99 -! g 1-3 寸 T—H 1 g m 0.97 卜丨 cn 〇 I CO rH 1 113 〇i 〇 CO rh 0. 33 0. 34 0. 33 LT3 CO o LO CO o m CO o CC ζ〇〇 eg c〇, o CC s 0. 36 0- 22 0. 29 c〇 m d 0. 36 0.32 CO 0 0. 34 ϋ 寸 Ο 0. 06 Ο o 0.15 0. 06 0.15 0.14 0. 07 0.13 0.05 LD CS g o t—i o 0. 06 o 」 0. 06 丨鋼板 s ρα CO CS3 cc LA eo 1 CM -1 5 o 05 CO CO CO c〇 CO 寸1 -40 - 201042056 [表 1-4] 表1·4Table 1-2 Steel plate (continued on the previous page) Chemical composition (% by mass) Index of corrosion resistance 値 No Ni Sb W Nb, V, Ti, B Ca 'REM A1 A2 A3 Remark 1 - - - One - -3.7 - - Invention Example 2 - - - - -LI - - Inventive Example 3 0.092 One - - - - -3.8 Inventive Example 4 0.049 0.06 - - - - - -2.1 Inventive Example 5 0.089 - 0.05 One - - - - 3 · 5 Inventive Example 6 0. 082 0.06 0.06 - - - - -1.8 Inventive Example 7 - 0. 05 - - - - ~1. 2 Inventive Example 8 - - 0. 08 - - - - -1.9 Inventive Example 9 0.06 0. 07 - - - - 41 Inventive Example 10 0,034 0.06 0. 07 Nb: 0.012 - - - -4.1 Inventive Example 11 - 0.11 0.08 Nb: 0.007, V: 0, 004 - - -4, 1 Inventive Example 12 - 0.04 0.10 V : 0.006, Ti: 0, 012 — — — ~3.6 Inventive Example 13 - 0.04 0.05 Nb: 0.008, Ti: 0.010 - - - -2-1 Inventive Example 14 0. 053 0.10 0. 04 Ti : 0.013 , B : 〇 _ 〇〇〇 9 - - - -4.0 Inventive Example 15 - 0.06 0. 05 B : 0. 0011 - - - -1·8 Inventive Example 16 - 0.07 0. 06 - Ca : 0.0020 - - -1.4 Inventive Example 17 0·068 0. 05 0.06 Ca : 0. 0023 - - -4.3 Invention Example 18 0. 001 0.05 0.06 Nb : 0.0088 Ca : 0, 0022 - - -2.2 Invention Example -39- 20104205 6 Remarks Inventive Example I Inventive Example I Inventive Example 1 Comparative Example I Comparative Example 1 Comparative Example 1 Comparative Example 1 Comparative Example 1 u Comparative Example 丨 Comparative Example 1 Comparative Example Comparative Example 1 Comparative Example 1 Comparative Example 1 Comparative Example 1 (Continued Page) ] 1 [ 1 \ 1 1 I ί ” 1 1 1 1 l 0.05 0- 06 I i _1 1 0. 031 0. 036 0.037 0. 001 0. 042 0. 001 0.035 0. 001 0.026 0.037 c>a S C5 0.032 0.001 1 0,036 0. 049 0.033 0. 028 U CO ifH 〇· inch y—i Ο 卜 1—1 d 5l CO b CO o CO o 0. 15 0-05 0-21 〇r-^ — d τΗ Ο 3 o ΙΟ oo CO ο β 0.086 0.093 0,052 so c5丨0. 030 0.081 (N 〇oo 0.009 0.006 0.007 0.003 0. 100 0.066 0.043 0.069 0-086 _ Tengyi 0-0023 0. 0025 0-0027 0.0036 0 0022 0. 0024 0, 0024 0. 0025 0, 0028 0.003 0. 0031 0.0029 0. 0025 0-0026 0-0028 0. 0022 0. 0029 soLAl 0.031 0. 031 0. 036 0.035 0.036 0.033 0.036 0.031 0.033 0. 035 0. 031 0.032 0.034 0.034 0. 035 0. 034 0. 036 ω 0. 0008 0. 0007 0. 0006 _ i B 0-0017 0-0019 0. 0008 0. 0007 0. 0016 0. 0013 0. 0013 0. 0006 0, 0009 0. 0120 0. 007 0.007 0.007 0.018 0.022 0-009 0.010 0.007 0.018 0. 007 0. 008 0.009 0.020 0.006 0. 008 0. 026 0. 012 τΗ rA Ο rH LA vH iJ CO CC lH 0.99 -! g 1-3 inch T-H 1 gm 0.97 丨Cn 〇I CO rH 1 113 〇i 〇CO rh 0. 33 0. 34 0. 33 LT3 CO o LO CO om CO o CC ζ〇〇eg c〇, o CC s 0. 36 0- 22 0. 29 c 〇md 0. 36 0.32 CO 0 0. 34 ϋ inch Ο 0. 06 Ο o 0.15 0. 06 0.15 0.14 0. 07 0.13 0.05 LD CS got-io 0. 06 o ” 0. 06 丨 steel plate s ρα CO CS3 cc LA eo 1 CM -1 5 o 05 CO CO CO c〇CO Inch 1 -40 - 201042056 [Table 1-4] Table 1·4

鋼板 (接續前頁）化學成分(質量％) 耐ft 巨性之指標値備註 No Ni Sb W Nb、V、 Ti、B Ca、REM A1 A2 A3 19 0. 042 0.06 0. 05 Ti：0, Oil Ca：0. 0026 - - -2.0 發明例 20 0. 053 0.06 0,06 V :0,004、 Ti :0. 012 Ca:0.0022 魅 - -4.3 發明例 21 0.039 0. 05 0.05 Ti :0.010 REM：0.0019 - - -2· 0 發明例 22 - - - - - 9.3 — - 比較例 23 0.011 - - - - - 0.2 - 比較例 24 - - - - -2.8 - - 比較例 25 - - - 一 - - 比較例 26 0. 033 0. 05 0. 06 Nb：0.009 , Ti:0.010 一 - 一 L1 比較例 27 0.100 0.04 0·05 - - - -2.1 比較例 28 0. 078 0.06 - Ca：0. 0025 - 一 -1,0 比較例 29 0.068 0.04 0. 06 Ti :0.012 Ca:0. 0023 一 — -3.4 比較例 30 - 0.05 0- 05 Nb:0. 012、 Ti：0. Oil - - 1.0 比較例 31 - 0_06 0.05 - - - Li 比較例 32 - 0.04 0. 06 一 - - - 2JL 比較例 33 0.044 0, 06 0.05 Nb:0.008 、 V :0.006、 Ti :0, 010 Ca: 0.0019 - — 1.5 比較例 34 0.057 0.05 0.05 Ti:0.011 Ca :0. 0020 - -0.7 比較例 35 - 0.05 0.05 - - - -0.3 比較例 -41 - 201042056 [表2] 表2 鋼板食鋅底漆塗佈材 No. 裝材平均厚度（/X m) 備註 5〜10 15 〜25 50 〜70 1 AO AO AO AA® 發明例 2 AO AO AO AA® 發明例 3 A〇 AO AA® AA® 發明例 4 AO AO AA® AA® 發明例 5 AO AO AA® AA® 發明例 6 AO AO AA® AA® 發明例 7 AO AO AA® AA® 發明例 8 AO AA® AA® AA® 發明例 9 AO AA® AA® AA® 發明例 10 AO AO AA® AA® 發明例 11 AO AO AA® AA® 發明例 12 AO AO AA® AA® 發明例 13 AO AO AA® AA® 發明例 14 AO AO AA® AA® 磋明惋 15 AO AO AA® AA® 發明例 16 AO AA® AA® AA® 發明例 17 AO AA® AA® AA® 發明例 18 AO AA® AA® AA® 發明例 19 AO AA® AA® AA® 發明例 20 AO AA® M® AA® 發明例 21 AO AA® AA® AA® 發明例 22 cx CX CX CX 比較例 23 cx ΒΔ ΒΔ ΒΔ 比較例 24 cx CX ΒΔ ΒΔ 比較例 25 cx CX CX CX 比較例 26 cx ΒΔ ΒΔ' ΒΔ 比較例 27 cx ΒΔ ΒΔ ΒΔ 比較例 28 cx ΒΔ ΒΔ ΒΔ 比較例 29 cx CX CX CX 比較例 30 cx ΒΔ ΒΔ ΒΔ 比較例 31 cx ΒΔ ΒΔ ΒΔ 比較例 32 cx CX CX CX 比較例 33 cx cx cx ΒΔ 比較例 34 cx cx cx ΒΔ 比較例 35 cx cx cx ΒΔ 比較例〈耐局部腐蝕性的評價〉 AA© :無局部腐蝕之發生 A〇：局部腐蝕之深度小於0.5mm ΒΔ :局部腐蝕之深度在0.5mm以上且小於1mm Cx :局部腐鈾之深度鳥1mm以上 -42- 201042056 [表3] 表3 ^_ 耐局部腐蝕性之評價備註鋼板No. 1 8 波來鐵小於2% ΒΔ A〇請求項6之比較例面積率 2%以上且小於5 A〇 A〇發明例 6%以上且小於10% A〇 A〇發明例 11 %以上 A〇 A〇發明例 0 <耐局部腐蝕性的評價> AA◎•無局部腐融之發生 A ◦ ·局部腐触之涂度小於0.5 m m ΒΔ:局部腐飽之深度在0.5mm以上且小於1.0mmSteel plate (continued on the previous page) Chemical composition (% by mass) Resistance to ft Giantity 値Remarks No Ni Sb W Nb, V, Ti, B Ca, REM A1 A2 A3 19 0. 042 0.06 0. 05 Ti:0, Oil Ca: 0. 0026 - - -2.0 Inventive Example 20 0. 053 0.06 0,06 V : 0,004, Ti :0. 012 Ca: 0.0022 Charm - -4.3 Invention Example 21 0.039 0. 05 0.05 Ti : 0.010 REM: 0.0019 - - -2· 0 Inventive Example 22 - - - - - 9.3 - - Comparative Example 23 0.011 - - - - - 0.2 - Comparative Example 24 - - - - -2.8 - - Comparative Example 25 - - - One - - Comparative Example 26 0. 033 0. 05 0. 06 Nb: 0.009, Ti: 0.010 I - L1 Comparative Example 27 0.100 0.04 0·05 - - - -2.1 Comparative Example 28 0. 078 0.06 - Ca: 0. 0025 - I-1 , 0 Comparative Example 29 0.068 0.04 0. 06 Ti : 0.012 Ca: 0. 0023 I - -3.4 Comparative Example 30 - 0.05 0- 05 Nb: 0. 012, Ti: 0. Oil - - 1.0 Comparative Example 31 - 0_06 0.05 - - - Li Comparative Example 32 - 0.04 0. 06 One - - - 2JL Comparative Example 33 0.044 0, 06 0.05 Nb: 0.008, V: 0.006, Ti: 0, 010 Ca: 0.0019 - - 1.5 Comparative Example 34 0.057 0.05 0.05 Ti: 0.011 Ca : 0. 0020 - -0.7 Comparative Example 35 - 0.05 0.05 - - - -0.3 Comparative Example-41 - 201042056 [Table 2] Table 2 Zinc-coated primer coating material No. Average thickness of the material (/X m) Remarks 5 to 10 15 to 25 50 to 70 1 AO AO AO AA® Invention Example 2 AO AO AO AA® Inventive Example 3 A〇AO AA® AA® Inventive Example 4 AO AO AA® AA® Inventive Example 5 AO AO AA® AA® Inventive Example 6 AO AO AA® AA® Inventive Example 7 AO AO AA ® AA® Inventive Example 8 AO AA® AA® AA® Inventive Example 9 AO AA® AA® AA® Inventive Example 10 AO AO AA® AA® Inventive Example 11 AO AO AA® AA® Inventive Example 12 AO AO AA® AA® Inventive Example 13 AO AO AA® AA® Inventive Example 14 AO AO AA® AA® 惋惋 15 AO AO AA® AA® Inventive Example 16 AO AA® AA® AA® Inventive Example 17 AO AA® AA® AA® Inventive Example 18 AO AA® AA® AA® Inventive Example 19 AO AA® AA® AA® Inventive Example 20 AO AA® M® AA® Inventive Example 21 AO AA® AA® AA® Inventive Example 22 cx CX CX CX Comparative Example 23 cx ΒΔ ΒΔ ΒΔ Comparative Example 24 cx CX ΒΔ ΒΔ Comparative Example 25 cx CX CX CX Comparative Example 26 cx ΒΔ ΒΔ' ΒΔ Comparative Example 27 cx ΒΔ ΒΔ ΒΔ Comparative Example 28 cx ΒΔ ΒΔ ΒΔ Comparative Example 29 cx CX CX CX Comparative Example 30 cx ΒΔ ΒΔ ΒΔ Comparative Example 31 cx ΒΔ ΒΔ ΒΔ Comparative Example 32 cx CX CX CX Comparative Example 33 cx cx cx ΒΔ Comparative Example 34 cx cx cx ΒΔ Comparative Example 35 cx cx cx ΒΔ Comparative Example <Local Corrosion Resistance Evaluation of properties > AA© : No local corrosion occurred A 〇: The depth of local corrosion is less than 0.5mm Β Δ : The depth of local corrosion is above 0.5mm and less than 1mm Cx : The depth of local uranium is more than 1mm -42- 201042056 [ Table 3] Table 3 ^_ Evaluation of resistance to local corrosion Remarks Steel plate No. 1 8 Boron iron is less than 2% ΒΔ A〇 The ratio of the comparison case of claim 6 is 2% or more and less than 5 A〇A〇Inventive example 6% Above and less than 10% A〇A〇Inventive Example 11% or more A〇A〇Inventive Example 0 <Evaluation of Local Corrosion Resistance> AA◎•No Local Corrosion Occurrence A ◦ ·The local corrosion degree is less than the coating degree 0.5 mm ΒΔ: the depth of local rot is 0.5mm or more and less than 1.0mm

Cx.局部腐触之丨朱度爲l.Ortim以上Cx. The local rot of the phlegm is more than l.Ortim

-43- 201042056 [表4] 表4 鋼板输涂意鋅底漆塗佈材 No. 裝材平均厚度（μm) 備註 5〜10 15 〜25 50 〜70 1 AO AO AO AO 發明例 2 AO AO AO AO 發明例 3 AO AO AO AO 發明例 4 AO AO AO AO 發明例 5 AO AO AO AO 發明例 6 AO AO AO AO 發明例 7 AO AO AO AO 發明例 8 AO AO AO AO 發明例 9 A〇 AO AO AO 發明例 10 AO AO AO AO 發明例 11 AO AO AO AO 發明例 12 AO AO AO AO 發明例 13 AO AO AO AO 發明例 14 AO AO AO AO 發明例 15 AO AO AO AO 發明例 16 AO AO AO AO 發明例 17 AO AO AO AO 發明例 18 AO AO AO AO 發明例 19 AO AO AO AO 發明例 20 AO AO AO AO 發明例 21 AO AO AO AO 發明例 22 CX cx CX CX 比較例 23 cx cx cx ΒΔ 比較例 24 cx ΒΔ ΒΔ ΒΔ 比較例 25 cx cx cx ΒΔ 比較例 26 cx cx cx ΒΔ 比較例 27 cx ΒΔ ΒΔ ΒΔ 比較例 28 cx CX cx ΒΔ 比較例 29 cx ΒΔ ΒΔ ΒΔ 比較例 30 cx CX ΒΔ ΒΔ 比較例 31 cx cx ΒΔ ΒΔ 比較例 32 cx cx CX ΒΔ 比較例 33 cx cx ΒΔ ΒΔ 比較例 34 cx cx ΒΔ ΒΔ 比較例 35 cx cx ΒΔ ΒΔ 比較例 <無塗裝材之耐全面腐蝕性的評價> A〇：腐蝕速度小於0.2mm/年 ΒΔ :腐蝕速度爲0.2mm/年以上且小於0.8mmy年 Cx :腐蝕速度爲0_8mm/年以上 <底漆塗佈材之耐全面腐蝕性的評價> A〇：鏽面積率小於25% ΒΔ :鏽面積率爲25%以上且小於50%-43- 201042056 [Table 4] Table 4 Zinc-primer coating material for steel plate transfer No. Average thickness of material (μm) Remarks 5 to 10 15 to 25 50 to 70 1 AO AO AO AO Inventive Example 2 AO AO AO AO invention example 3 AO AO AO AO invention example 5 AO AO AO AO invention example 6 AO AO AO AO invention example 7 AO AO AO AO invention example 8 AO AO AO AO invention example 9 A 〇 AO AO AO invention example 10 AO AO AO AO invention example 12 AO AO AO AO invention example 13 AO AO AO AO invention example 14 AO AO AO AO invention example 15 AO AO AO AO invention example 16 AO AO AO AO Inventive Example 18 AO AO AO AO Inventive Example 19 AO AO AO AO Inventive Example 20 AO AO AO AO Inventive Example 21 AO AO AO AO Inventive Example 22 CX cx CX CX Comparative Example 23 cx cx cx ΒΔ Comparison Example 24 cx ΒΔ ΒΔ ΒΔ Comparative Example 25 cx cx cx ΒΔ Comparative Example 26 cx cx cx ΒΔ Comparative Example 27 cx ΒΔ ΒΔ ΒΔ Comparative Example 28 cx CX cx ΒΔ Comparative Example 29 cx ΒΔ ΒΔ ΒΔ Comparative Example 30 cx CX ΒΔ ΒΔ Comparative Example 31 cx cx ΒΔ ΒΔ Comparative Example 32 cx cx CX ΒΔ Comparative Example 33 cx c x ΒΔ ΒΔ Comparative Example 34 cx cx ΒΔ ΒΔ Comparative Example 35 cx cx ΒΔ ΒΔ Comparative Example <Evaluation of general corrosion resistance of no coated material> A〇: Corrosion rate is less than 0.2 mm/year ΒΔ: Corrosion rate is 0.2 Mm/year or more and less than 0.8 mmy year Cx: Corrosion speed is 0_8 mm/year or more <Evaluation of general corrosion resistance of primer coating material> A〇: rust area ratio is less than 25% ΒΔ: rust area ratio is 25 More than % and less than 50%

Cx :鏽面積率爲50%以上 -44 - 201042056 [表5] 表5 耐局部腐蝕性之評價備註鋼板No. 1 8 波來鐵小於2% ΒΔ ΒΔ 請求項6之比較例面積率 2%以上且小於5% A〇 Α〇發明例 6%以上且小於10% A〇 Α〇發明例 11%以上 A〇 A〇發明例 0 <無塗裝材之耐全面腐蝕性的評價> A〇：腐鈾速度小於0.2mm/年 BZ\:腐蝕速度爲0.2mm /年以上且小於0.8mm /年 Cx:腐蝕速度爲0.8mm/年以上【圖式簡單說明】 [圖1 ]說明局部腐鈾試驗裝置之圖。 [圖2 ]說明全面腐蝕試驗裝置之圖。〇【主要元件符號說明】 1、 11 :試驗片 2、 1 2 :腐鈾試驗槽 3 :恒溫槽(constant-temperature bath) 4、 14 :導入氣體 5、 1 5 :排出氣體 6、 1 6 :試驗液（t e s t 1 i q u i d ) 7 :水 -45- 201042056 1 3 :溫度控制板Cx : rust area ratio is 50% or more -44 - 201042056 [Table 5] Table 5 Evaluation of local corrosion resistance Remarks Steel plate No. 1 8 Borne iron is less than 2% ΒΔ ΒΔ The comparison example area ratio of claim 6 is 2% or more And less than 5% A 〇Α〇 Inventive Example 6% or more and less than 10% A 〇Α〇 Inventive Example 11% or more A 〇 A 〇 Inventive Example 0 < Evaluation of general corrosion resistance of no coated material > A〇 : uranium speed is less than 0.2mm / year BZ\: corrosion rate is 0.2mm / year and less than 0.8mm / year Cx: corrosion rate is 0.8mm / year or more [schematic description] [Figure 1] illustrates localized uranium Diagram of the test device. [Fig. 2] A diagram illustrating a general corrosion test apparatus. 〇 [Main component symbol description] 1, 11: test piece 2, 1 2: uranium test tank 3: constant-temperature bath 4, 14: introduction of gas 5, 15: exhaust gas 6, 16: Test 1 iquid 7 : Water -45- 201042056 1 3 : Temperature control board

ί -46-ί -46-

Claims

201042056 VII. Patent application scope: 1 · A corrosion-resistant steel for crude oil oil tank, characterized by C: 0.001 to 0.16 mass%, Si: 1.5 mass% or less, Μη: 0·1 to 2.5 mass%, Ρ: 0.025 mass % or less, 0 S: 0.01% by mass or less, A1: 0.005 to 0.1% by mass, N: 0.001 to 0.008% by mass, Cu: 0.008 to 0.35 mass%, Cr: more than 0.1% by mass, and 0.5% by mass or less. Sn: 0.005 to 0.3% by mass, and Mo: 0.01% by mass or less, and the remainder of the ruthenium is Fe and unavoidable impurities, wherein 値 of A1 defined by the following formula (1) is 0 or less; = 28X [C] +2 0 0 0X [P] 2+2 7 0 0 0 X [S] 2+〇0 0 8 3 X (1/ [Cu] ) +0. 027X (1/ [Cr] ) + 95X [Mo] +0. 0 0098X(l/[Sn])-6 .-. (1) Here, [c], [P], [s], [Cu], (Cr) in the above formula 〕' [Mo] and [Sn] are the content of each element (% by mass). 2. For the crude oil tank of claim 1, the corrosion-resistant steel of 'the' is -47- 201042056 Ni: 0.005 to 〇·4% by mass, and 値2 defined by the following formula (2) is 0 or less; A2 = 28X [C] + 2 000 Χ [Ρ] 2+2 7 0 0 0 Χ [ S] 2+〇. 0 0 8 3 X (l/[Cu]) +2Χ [Ni] + 0. 027Χ (l/[Cr]) +95Χ [Mo] +〇. 00098X (l/[Sn]) -6 · (2) Here, the contents of the respective elements of [c], [P], [s], [Cu], [Ni], [Cr], [Mo], and [Sn] in the above formula ( (% by mass). 3. Corrosion-resistant steel for crude oil tanks according to claim 1 or 2, wherein, in addition to the above composition, further contains W: 〇.001~(^5 mass% and Sb: 0.005~0_3 mass% One or two of the selected ones, and the 値 of A3 defined by the following formula (3) is 0 or less; A3 = 28X [C] + 2000X [P] 2+27000X [S] 2+0. 0083 X (l/[Cu]) +2X [Ni] +0. 027X (l/[Cr]) +95X [Mo] +〇. 00098X (l/[Sn])+〇. 〇〇19X (l/( [sb] + [W] ) ) -6. 5 • · (3) Here, [c], [P], [S], [Cu]' [Ni], [Cr], [Mo], [Sn], [Sb] and [W] Elements of content (% by mass). 4. The corrosion-resistant steel material for a crude oil sump according to any one of claims 1 to 3, further comprising Nb: 0.002 to 0.1% by mass, V: 0.002 to 0.1% by mass, Ti: 0.001 in addition to the above component composition. ~0.1 质-48- 201042056 重量%和B: 0.01% by mass or less selected one or two of the following 5. The crude oil sump according to any one of claims 1 to 4 is resistant to corrosion, wherein, in addition to the above components The composition further includes one or two selected from 0.0002 to 0.005 mass% and REM: 0.0005 to 0.015 mass%. 6. The rust-resistant worm of the crude oil tank of any one of claims 1 to 5, wherein the micro-structure of the steel sheet having a thickness of 1 / 4 contains a wave of iron with an area of 0 to 20% (pearlite) ). 7. The crude oil sump according to any one of claims 1 to 6 is resistant to corrosion, and is formed by forming a film containing a metal Zn or Zn compound on the surface of the steel material. 8. Corrosion-resistant steel for crude oil tanks according to claim 7, wherein the Zn content in the membrane is 1.0 g/m2 or more. A method for producing a corrosion-resistant steel material for a crude oil oil tank, which comprises heating a crucible having the composition of any one of claims 1 to 5 to 1 000 to 1 3 50 ° C, and then rolling The temperature was 750 ° C, and the inter-heat rolling was carried out, and the cooling was performed at a cooling rate of 2 ° C /sec or more until the cooling stop temperature of ° C or lower and 450 ° C or higher. 10. A crude oil tank characterized by the use of a steel of one of claims 1-8. on. Steel Ca: Among the steel rate meters, the coating of steel, the coating characteristics of steel, above 650, -49-