Wall-Tube Corrosion in Steam-Generating Equipment Operating Around 1300 Psi

The author describes several instances of boiler-tube failures of the “brittle type” and the nonbrittle. In the brittle type the metal is decarburized under the corrosion products on the water side. Intercrystalline cracks occur in the decarburized areas. The author’s experience indicates that this type of failure may be due to the presence of dissolved oxygen in the feedwater in the absence of a suitable oxygen scavenger in the boiler water. The nonbrittle type of corrosion described was due to caustic attack on the tube metal. The grain structure was normal in this type of corrosion and no intercrystalline cracking occurred. These types of failures have been stopped by proper water treatment.