High temperature oxidation and erosion of 304 stainless steel under coal-fired boiler atmospheres

摘要

This work concerns the behaviour of a fully annealed 304 stainless steel subjected to the action of postcombustion gases from a coal-fired boiler cornbustor. The study first evaluates the oxidation rates of the steel in atmospheres with 3-3.5% of free oxygen at 500, 600 and 800℃(773, 873 and 1073 K). The low velocity corrosion-erosion behaviour produced by the impact of fly ashes existing in the gas stream at high temperatures (873 and 1073 K) was also evaluated, under impact angles of 30°and 90°.The operating erosive micromechanisms were determined and the influence of the ash embedment phenomenon, chemical reactions between the austenitic steel and ash particles and finally the effect of the surface scale characteristics have also been elucidated.