本研究主要探討A213-T11低合金鋼在高溫富氧之環境下之硫氧化現象。前段部分主要分析實際應用於重油裂解（Residue Catalytic Cracking,RCC）製程中之破損爐管的腐蝕原因，並根據前段破損分析之結果擬定試驗條件，對破損爐管原材料分別進行模擬試驗。同時藉由分析腐蝕產物的化學組成及微觀組織，以了解其反應機制。
針對破損爐管外層銹皮之分析，結果顯示其銹層中除氧化物外，亦有硫化物與其交錯呈層狀分佈之現象，顯示爐管之操作環境中含有硫或其化合物存在。為了解此現象發生之原因，使用爐管之基材製成試片，並於不同硫分壓下進行持溫以觀察試片之腐蝕行為。系統之含硫氣氛以加熱含硫鋼罐產生硫蒸氣並以氮氣為載體將硫蒸氣通入高溫管型爐中，藉由控制鋼罐溫度以控制系統之硫分壓。結果顯示，作為爐管基材之A231-T11低合金鋼於純氧化及較低硫分壓之環境下，腐蝕動力學遵守拋物線規則，顯示銹層之增長以離子擴散作為速率決定步驟。而隨著持溫環境中之硫分壓上升，試片之增重也隨之增加。而由XRD分析結果可知，試片在含硫環境中氧化20分鐘後，銹層內層出現了硫、氧化物之混合層，而隨著環境中硫分壓的提升，硫化物在銹層內層呈現層狀交錯之分佈。

High temperature corrosion behavior of ASTM A213-T11 low alloy tube steel in sulfur-containing atmosphere at 980 oC was studied. First part of this study is to clarify the corrosion behavior of fracture tube used in residue crude cracking process. According to the analysis result, the base material of the tube (A231-T11 low alloy steel) may use as specimen for oxidation, sulfidation and mixed oxidation/sulfidation simulation test. Sulfur vapor is generated by heating up the can which contains pure sulfur powder. Corrosion test was conducted in a tube furnace in which dilute sulfur vapor carried by nitrogen gas was purged. By altering the temperature of sulfur-containing can, the sulfur partial pressure of system can be controlled. The parabolic rate constant is observed on oxidation and low sulfur partial pressure test. As the sulfur pressure increase, the weight gain of sample increases in the same time. The XRD result shows that when sample oxidizes in sulfur containing environment for 20 min, FeS is observed on the inner part of the scale. As the sulfur partial goes up, the FeS in inner scale distribute in laminar way.

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