The paper analyzes the fracture reason of the corrugated plate by the method of scanning electron microscope（ SEM）

metallographic microscope

spectroanalysis instrument

and pinots out that dew point corrosion occurs not only at the surface of the corrugated plate

resulting in the thinning of the plate

but also occurs and forms cores in the inner part of the plate. Serious dew point corrosion results in the severe decrease of strength of the corrugated plate and the the corrugated plate is broken due to the impact of the blowing steam. At last the paper concludes precaution of preventing dew point corrosion under the condition of current technology.