The reduction of carbon dioxide emissions and increasing energy demand are the driving forces behind the further development of solar power plants. Figure 1. Shows the schematic structure of the concentrating solar power plants (CSP), which convert the absorbed sunlight into thermal energy and consequently to electricity. Two-tank TES systems are operated with molten salt, a mixture of 60% NaNO3 and 40% KNO3, which transfers the heat of the sunlight from the receiver to the storage tank. In this system, the key part that transfers sunlight to the heat storage medium is a central receiver. Structural materials applied in the central receiver must meet certain requirements: Manufacturability, mechanical performance and corrosion resistance. [1,2,3]

 

Figure 1. schematic structure of concentrating Solar power plant. [4]

This study mainly focused on the interaction between the mechanical properties, corrosion resistance, and the capability to manufacture thin-walled tubes (central receiver). The working temperature of the central receiver can exceed 560 °C, which leads to high-temperature corrosion when it is in contact with molten salt. It has been proven that the microstructure and temperature have a direct impact on mechanical properties as well as corrosion resistance of the steel. [5,6] Therefore, the applied material in this work, austenitic stainless steel 310N, with different grain sizes will be produced and then exposed to the highly corrosive medium at different temperature and holding time. Subsequently, the mechanical properties of the tested samples will be investigated to study the influence of grain size on the mechanical properties of our steel in corrosive environment.