A method for evaluating the safety of the corrosion fatigue of a high-pressure (HP) drum for the heat recovery steam generator (HRSG) is presented through a transient thermal stress analysis. To evaluate the corrosion fatigue, European Standard EN 13445-3 is applied to check whether the magnetite protective layer on the water-contacting surface can be preserved during the transient operating conditions: cold start, hot start, warm start, and load change. Static analysis is performed to analyze the stress due to the operating pressure, and transient thermal and structural analyses are performed for the transient operating conditions. As per EN 13445-3, the analyzed maximum and minimum stresses of the transient operating conditions at representative locations are compared with the allowable limits derived from the stress due to the operating pressure. In conclusion, the magnetite protective layer was preserved under the transient operating conditions and the HP drum was found to be safe for the corrosion fatigue. The method of analyzing the thermal stress and evaluating the safety of the corrosion fatigue presented in this research can be applied effectively in the design stage of various unfired pressure vessels exposed to high temperature and high pressure loading.

Grate Bars used in the sintering process of steel companies are exposed to high temperatures, oxidation and abrasive environments. To extend the lifetime of the Grate Bar, surface coating was applied to enhance performance at high temperatures and reinforce abrasion resistance. To evaluate mechanical and chemical properties of these coatings, various tests such as abrasion resistance testing and high temperature oxidation testing were conducted. Based on results of the tests, selection of applicable coating materials and techniques were obtained in the field.