Inconel 625 is widely used in various industrial fields due to its excellent comprehensive performance. With the development of various industries, the performance requirements of Inconel 625 alloy are getting higher and higher, so it is very necessary to further improve the structure and performance of Inconel 625 alloy. This paper summarizes the research on the forming preparation, structure performance, molten salt corrosion and other aspects of Inconel 625 alloy by domestic and foreign scholars in the past 7 years. The forming method is reviewed from the aspects of 3D printing technology (i.e. additive manufacturing) and surface modification technology; the performance mainly summarizes the chemical composition and heat treatment process; the molten salt corrosion focuses on fluoride salts, nitrates, carbonates, sulfates, etc. Finally, the future development prospects of Inconel 625 alloy are proposed, which provides practical guidance for the future research of Inconel 625.

Keywords: Inconel 625; forming; structure performance; molten salt corrosion

Inconel 625 alloy has excellent comprehensive performance. Even in a high temperature environment of 980 ℃, it can still maintain good tensile mechanical properties and fatigue stability [1-2]. This alloy with a face-centered cubic structure can withstand a variety of harsh environments, especially in chloride media, and has good corrosion resistance [3]. Therefore, it can be widely used in various aviation equipment and gas turbines, nuclear industry, chemical industry and other fields [4-5]. At present, the rapid development of new energy such as solar thermal power generation and energy storage has led to the emergence of high temperature and harsh corrosion environments, which requires alloy materials as high-temperature components to have better comprehensive properties. The development of high-temperature alloys with better performance is an urgent problem to be solved. This paper summarizes the molding, molten salt corrosion and performance of Inconel 625 alloy at home and abroad in the past 7 years, laying the foundation for the subsequent research of Inconel 625 alloy.

1 Molding method

Inconel 625 alloy has good tensile strength, yield strength, endurance and plasticity at high temperature, and has good resistance to high temperature oxidation and corrosion in harsh environments. Therefore, it is widely used in aerospace, chemical, petroleum, marine and nuclear power fields. However, nickel-based corrosion-resistant high-temperature alloys are currently mostly produced using a double or triple melting process, that is, the raw materials are first melted in a vacuum induction furnace and cast into a master alloy ingot, and then the master alloy ingot is remelted and cast into a casting. The traditional production process has disadvantages such as high energy consumption and low yield rate. The prepared alloy ingots also have defects such as coarse grains, shrinkage cavities and severe element segregation. Compared with the traditional die casting process, the continuous casting process has the advantages of low energy consumption and high yield rate. However, for Inconel 625 alloy, there is no mature continuous casting technology in China that has been put into production, and the technology is kept secret abroad. Therefore, in the face of the current situation of my country’s increasing demand for high-temperature alloys, the research and development of Inconel 625 alloy continuous casting technology has important innovative and practical value [6]. The following are some molding methods of Inconel 625 alloy.