| Summary: | 碩士 === 國立成功大學 === 材料科學及工程學系 === 105 === 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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