CREEP DEFORMATION AND RUPTURE OF INDUCTION PRESSURE WELDED 2.25CR-1MO STEEL IN HOT CORROSION .2. MICROSTRUCTURAL ASPECTS

Microstructural changes accompanying both creep tests at various temperatures and stresses, and static hot corrosion tests, in an induction pressure welded 2.25Cr-1Mo steel have been studied using optical microscope. The formation of various carbides on the grain boundaries as well as within the grains is attributed to be the reason for the weakening of the material. Further the formation of oxides and sulphides on the surface of the corroded samples causes weakening of the material by reducing the available cross section leading to early failure of coated samples. The results are substantiated by hardness survey along the gauge length.