In modern industrial world, engineering components are prone to more rapid surface degradation such as erosion-corrosion, overheating, wear, solid particle abrasion, high temperature corrosion, etc. Due to above surface degradation, major problems causes tube wall thinning, results in premature failure of the super heater and reheater tubes. Alloys used at high temperature should possess good mechanical properties along with erosion - corrosion resistance. The present study behavior of boiler steel ASTM-SA213 T-22 (used in most of the power plants in the Northern India) has been investigated for high temperature erosion-corrosion behavior in the uncoated as well as coated condition. Detonation Gun thermal spraying process was used for coating on boiler steel. SEM/EDAX, XRD and X-ray mapping analysis done to reveal the microstructure and compositional features of boiler steel. The microstructure indicates uniform and dense coating. Thermogravimetric techniques is used to investigate the erosion-corrosion behavior at 900 C for 1000 hours. SEM/EDAX, XRD and X-ray mapping techniques were used to analyze the corrosion products."

There is extensive work on the fracture of steel with ferrite and austenite structure, but little on fracture behaviour of ADI, whose microstructure also comprises austenite and ferrite. The present work is aimed in this direction. The role of austempering tempeature on the fracture behaviour of Ni-Mo austempered ductile iron has been studied. In present work, the fractographic and fractomicrographic features of the fractured specimens austempered at 270, 330, 380 C for 1 hr and broken in tensile test and impact test, respectively, have been studied. The matrix of ADI is a complex mixture of austenite, bainitic ferrite needles with or without carbide particle depends upon the austempering temperature. The matrix of ADI can withstand a certain amount of deformation before fracture during tensile or impact testing, however the graphite nodules in the matrix cannot deform and hence are barrier to matrix deformation and give rise to crack initiation. The crack propagation is influenced by the orientation of bainitic ferrite with respect to load direction, also by the presence of carbide particles inside the needles. Thus producing characteristic features."