The abrasion/erosion and erosion-corrosion characteristics of steels

The metal wastage which occurs on the combustion gas side of in-bed heat exchanger tubes in fluidized bed combustors (FBCs) is an important problem in this method of generating power from coal. The particle flow conditions which occur along the tube surfaces that remove material are the subject of some speculation as to whether three-body abrasion or solid particle impact erosion is causing the degradation. In this paper, evidence is presented that shows that the basic mechanism of particles degrading the surface is essentially the same for both descriptions of the active mechanism. The ability to extrapolate to long-term metal wastage rates in actual in-service FBC exposures from short-term laboratory tests that reach steady state loss rate conditions in the order of 5 h is also discussed. The concept of trading off various test conditions such as test temperature and particle size, shape, and velocity to realize similar amounts of metal wastage from balanced test conditions is presented.