Studies on High-Temperature Corrosion resistance of low carbon Steel in Actual boiler environment

Abstract

In coal based power generated plants, hot corrosion and erosion are identified as serious problems, resulting in deterioration of boiler tube. In this present study, the High-Temperature Corrosion behavior of bare SA 210 Gr. A1 steel and Friction stir processed Cr3C2-25(NiCr) inserted Gr. A1 steel samples were compared under cyclic condition of 1500 hours in actual both environments. The kinetics of hot corrosion was measured on the base of weight-change after each cycle. The tool rotation speed for three processed samples were recorded as 1600rpm, 2000rpm, 2400 rpm respectively with transverse speed of 30 mm/min processed by three number of passes. Microstructure evolution of base and FSPed was done by electron back scatter diffraction (EBSD). X-ray diffraction (XRD)and scanning electron microscopy (SEM) along with energy dispersive spectroscopy (EDS) were performed on the exposed sample to analyze the corrosion products. The base steel sample suffered extreme erosion-corrosion in actual boiler environment, where as processed samples exhibits better hot corrosion resistance (64%, 66%, 73%) respectively. The processed samples also showed 4 fold refined grains, as confirmed by (EBSD).