Failure Mechanism of the Hot-dipped Aluminide Coating on Dissimilar Weldments in High Temperature Applications

• Main Authors: QING-LIN ZHU, 朱慶霖
• Other Authors: none
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/73572176611636506906

碩士 === 國立臺灣科技大學 === 機械工程系 === 103 === Gas tungsten arc welding (GTAW)was applied to join AISI 304 stainless steel and AISI 1015 carbon steel with consumable – AISI 309L stainless steel wires. The oxidation test was performed by placing weldments at 750 ℃ after hot-dip pure aluminum. Welded specimen’s thermal stress distribution under high-temperature environment was simulated by ANSYS.The experimental results are compared with the results of simulation and determine the damage of intermetallic scale. The result shows that because of the thermal expansion coefficient difference between welded materials, causes thermal stress to occur during heating process , and heating cracks inside the scale above the Fusion zone of Low carbon steel(FZL).The aluminide scale will Strip after High-temperature diffusion in a short time. The Kirkendall voids and heating cracks inside the aluminide layer grows during the high temperature diffusion. The voids inside the aluminum layer will congest, until the holes were connected with cracks to form a continuous cracks and cause aluminide scale on HAZL to peel off.