文章信息/Info

Title:

Wet-dry Corrosion Behavior of Low Alloy Steel in CO2-O2-H2S-SO2 Atmosphere of Cargo Oil Tanks of Crude Oil Tankers

作者:

朱祎淳; 柳  偉; 趙慶賀; 趙永剛; 張彬禮; 李曉剛

（北京科技大學(xué)新材料技術(shù)研究院腐蝕與防護(hù)中心，北京100083，中國(guó)）

Author(s):

ZHU Yichun; LIU Wei*; ZHAO Qinghe; ZHAO Yonggang; ZHANG Binli; LI Xiaogang

（Corrosion and Protection Center, Institute for Advanced Materials and Technology, University of Science and Technology Beijing, Beijing 100083, China）

關(guān)鍵詞:

低合金鋼; 合金元素; 銹層; 貨油艙

Keywords:

low alloy steel;  alloy elements;  rust;  cargo oil tank

DOI:

10.7502/j.issn.1674-3962.2018.01.06

文獻(xiàn)標(biāo)志碼:

A

摘要:

對(duì)碳鋼和Cr-Cu-Ni低合金鋼進(jìn)行模擬原油船貨油艙上甲板環(huán)境的CO₂-O₂-H₂S-SO₂干濕交替腐蝕實(shí)驗(yàn)，通過失重法獲得模擬貨油艙上甲板環(huán)境條件的腐蝕速率、對(duì)銹層物相組成以及進(jìn)行腐蝕電化學(xué)測(cè)試。結(jié)果表明，Cr-Cu-Ni低合金鋼腐蝕初期減薄量大于碳鋼，但隨著腐蝕時(shí)間延長(zhǎng)，Cr-Cu-Ni低合金鋼腐蝕速率低于碳鋼。相比于碳鋼腐蝕電流密度降低幅度小的特點(diǎn)， Cr-Cu-Ni低合金鋼腐蝕電流密度由裸鋼的67.4 μA/cm2顯著降低至帶銹鋼的11.7 μA/cm2。碳鋼銹層內(nèi)存在較大的貫穿整個(gè)銹層截面的裂紋，而Cr-Cu-Ni低合金鋼中的耐蝕合金元素Cr、Cu及Ni加入使銹層顆粒細(xì)小，結(jié)構(gòu)致密，銹層內(nèi)部截面裂紋細(xì)小。兩種鋼銹層均由非晶態(tài)腐蝕產(chǎn)物，α-FeOOH，少量的γ-FeOOH，F(xiàn)e₃O₄和單質(zhì)S組成。相比碳鋼的銹層，Cr-Cu-Ni低合金鋼銹層具有較高的非晶態(tài)物質(zhì)含量及較大α/γ值（α-FeOOH與γ-FeOOH含量比），從而使銹層具有高的致密度和保護(hù)性。

Abstract:

Electrochemical corrosion behavior of carbon steel and Cr-Cu-Ni low alloy steel with rust forming in simulated CO2–O2–H2S–SO2 wet–dry environment of cargo oil tanks of crude oil tankers for 98 days were investigated using corrosion rate by mass loss method, scanning electron microscope, X-ray diffraction, and electrochemical measurement. The results showed that the corrosion rate of Cr-Cu-Ni low alloy steel was higher than carbon steel in initial period, while with the increase of corrosion time, it was tend to be lower than carbon steel. The corrosion current density of Cr-Cu-Ni low alloy steel reduced greatly from 67.4μA/cm2 to 11.7μA/cm2 in comparison with a little special of the decreasing of carbon steel corrosion current density. The rust layer of carbon steel existed the larger cracks throughout the cross-section of it. Cracks existed throughout the cross-section of rust layer of carbon steel, while the rust of Cr-Cu-Ni low alloy steel was compact due to the small size of rust particles, leading to smaller crack in cross-section of the rust. The rusts of both carbon steel and Cr-Cu-Ni low alloy steel were composed of amorphous corrosion products, α-FeOOH, small account of γ-FeOOH, Fe3O4 and element S. However, no obvious difference between the phase compositions of the two kinds of steel rust existed. Compared to the rust of carbon steel, the rust of Cr-Cu-Ni low alloy steel had high content of the amorphous corrosion product and high α/γ value, i.e. the content ratio of α-FeOOH to γ-FeOOH, leading to high rust compactness.