碳鋼焊接在原油中之腐蝕行為

An EIS Study of Corrosion Behavior for Welded Carbon Steel in Crude Oil

張英傑(Ying-Chieh Chang)

指導教授 ： 薛文景

國立臺北科技大學/工程學院/材料及資源工程系所/碩士(2006年)

https://doi.org/10.6841/NTUT.2006.00054

摘要

本研究為利用交流阻抗頻譜法(Electrochemical Impedance Spectroscopy, EIS)針對碳鋼焊接之母材區、熱影響區及焊接區在原油浸置於不同時間及不同溫度下之腐蝕行為探討。焊接之碳鋼材料浸置於100℃下之原油浴中，經電化學交流頻譜阻抗測試發現，不論母材區、熱影響區或焊接區之腐蝕行為均顯示第一週至第七週之系統因氧化膜形成初期不穩定所以總組抗隨時間做大小不均改變，第八週至第十二週之系統總組抗明顯增大顯示其氧化膜顯著增加。
碳鋼焊接試片浸置於0℃、25℃、100℃及300℃之原油浴一週後之，經電化學交流頻譜阻抗測試結果顯示，浸置於0℃、25℃及100℃之原油浴中之試片表面並無明顯之?袧h產生，因0℃、25℃之原油浴中因溫度較低而導致原油變得更為稠密依附在試片上之油膜較厚，所以在Nyquist圖之半圓直徑顯現出較大，試片浸置於300℃高溫之原油浴，一週後取出觀察試片表面具有明顯的緻密之黑色氧化層腐蝕生成物形成，其Nyquist圖之半圓直徑較大於浸置於100℃原油之試片。因此；碳鋼焊接浸置於不同原油溫度而言，0℃、25℃及100℃之原油浴中短時間內對材料並不會造成明顯之腐蝕行為，而在高溫下〈300℃〉之原油浴中短時間即會對材料造成明顯之腐蝕結果。
實驗結果經利用之等效電路模擬軟體模擬出等效電路圖發現，不論試片浸置於100℃原油中經過不同時間或是試片浸置於不同溫度一週後，等效電路之模擬結果顯示整個腐蝕層可建構為電解液/原油/?袧h/金屬。

關鍵字

碳鋼焊接 ； 交流阻抗頻譜法 ； 等效電路圖

並列摘要

Corrosion behaviors for Welded carbon steel in crude oil of different temperatures and immersion times were investigated by Electrochemical Impedance Spectroscopy (EIS) method, The experimental results were analyzed by basic charts of EIS-Nyquist , Bode,and Bode phase plots. The stability of oxide films formed on the specimen was increased especially for those for 7th weeks of crude oil immersions at 100℃.
EIS test results reveals that the corrosion resistance on the base material, heat effected and welded zones of specimen would enhanced.
The research also include simulation of the equivalent circuit of the research system and indicated that the corrosion of specimen surface compose of base material/oxide film/crude oil/ electrolyte.

並列關鍵字

Welded carbon steel ； Electrochemical Impedance Spectroscopy (EIS) ； equivalent circuit

參考文獻

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