The High-temperature Creep Behavior of A36 Mild Steel Weldments with Hot-dipped Aluminum in NaCl/Na2SO4 Hot-corrosion Environments

• Main Authors: Li-Lin Lai, 賴立霖
• Other Authors: Chaur-Jeng Wang
• Format: Others
• Language: zh-TW
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/u6ncmy

碩士 === 國立臺灣科技大學 === 機械工程系 === 106 === 　　The main objective of the current research was to determine and compare creep resistance of uncoated weldment in a low-carbon steel material with that of an aluminized weldment of a similar low-carbon steel substrate. The experiment was conducted in an environment containing salt solution by depositing about 2 mg/cm2 mixture of NaCl/Na2SO4 at 750 C. 　　The experimental results show that similar welded parts of the low-carbon steel substrate in hot corrosion environment formed a thick oxide film which prevented decarburization and abnormal grain growth. Thus, the low-carbon steel similar welded parts are stretched in hot corrosion environment with two hours higher creep life. 　　After the hot-dip aluminizing process of the low carbon steel similar weldment, the aluminide coating highly improved oxidation resistance of the substrate material at high-temperature exposure. During creep test, aluminized coatings due to its high hardness slowed down the necking phenomenon and therefore delayed the rupture time increasing creep life by 17 hours under high temperature oxidation. The aluminized substrate under creep test in hot corrosion showed similar improvement as that tested in simple high temperature environment. Key words: Low carbon steel; Similar weldment; Hot dip aluminizing; Hot corrosion; Creep