Pure Bending Testing of Cr-Mo Alloy in Metal Dusting Condition

Metal dusting is a catastrophic corrosion phenomenon that leads to the disintegration of structural metals and alloys into dust composed of fine particles of the metal/alloy and carbon at high temperature. Considerable research efforts has been taken on the initiation of metal dusting in the alloy since it was observed. However, the previous researches were focused mostly on the initiation mechanisms of metal dusting without external applied loads. In fact, structural materials are mostly used with external applied loads. It is thus necessary to study the initiation and propagation mechanism of metal dusting in the stressed condition. In the present work pure bending testing of Cr-Mo alloy in metal dusting condition was performed. The laboratory experiments were performed at 560°C, using a synthesis gas mixture with composition 75%H2 + 25%CO. The maximum bending stresses were 100MPa, 50MPa, 10MPa and 0MPa, respectively. Post exposure metallographical examinations, SEM, EDX analysis were made in order to identify the difference between loaded and unloaded specimens. The effect of mechanical and chemical interaction on high temperature corrosion was preliminary discussed.