Development of sulfuric and hydrochloric acid dew-point corrosion-resistant steels: 2. Reliability verification of new corrosion-resistant steel by field test

A newly developed low-alloy corrosion-resistant steel shows superior properties to sulfuric and hydrochloric acid dew-point corrosion as well as excellent mechanical properties, weldability and machina-bility with attention to low cost and high efficiency. In addition, welding materials which can accommodate the corrosion-resistant properties and mechanical properties of newly developed low-alloy corrosion-resistant steel have also been developed. Generally, to assess corrosion performance of developed steels, specimens were evaluated by laboratory corrosion tests in a simulated field environment. However, a flue gas desul-furization (FGD) system included several environmental parameters such as change of corrosion environment depending on shutdown/operation of power plants, location of steels in facilities and velocity of a moving fluid. Therefore, to verify the reliability of newly corrosion-resistant steel, plant qualification test is necessary. In an actual environment, new developed low-alloy corrosion-resistant steel was proved to have better corrosion resistance than the other steels (existing corrosion-resistant steels and ordinary carbon steel).