High Temperature Slag Corrosion of Metallic Materials

Abstract

Abstract An examination of failed fireside metal parts and the development of remedial surface treatments are described. Observations of failed service parts and fireside exposed specimens showed scaling and accelerated oxidation of surfaces. Type 309 stainless steel showed corrosion characteristics similar to Type 310. Examination of a 60 percent Cr- 40 percent Ni specimen and a Type 310 specimen showed that the former had an 80 percent greater resistance to slag corrosion than the Type 310 stainless steel. The effect on fuel-ash corrosion of simple alkaline washes, paints and metal oxide water slurries applied directly to contaminated surfaces was determined. The following fire-side treatments were assesseed for corrosion control: (1) water washing, (2) anneal plus water wash, (3) lime slurry coating plus anneal plus water washing. The latter treatment was highly effective. A ship-board treatment requiring no complicated equipment and little interference to boiler operation is proposed. 4.2.3