A research team led by Dr. Sang-won Lee at the Department of Titanium in Advanced Metals Division at the Korea Institute of Materials Science succeeded in localizing the technology for manufacturing titanium compressor blades, a core component of the next-generation complex gas turbine, through joint research with HANSCO, Pusan National University, S&W, and JINYOUNG TBX. Korea Institute of Materials Science(KIMS) is a government-funded research institute under the Ministry of Science and ICT.

Titanium compressor blades can draw in atmospheric air in a wide flow path and compress it. Compared to existing steel materials, titanium compressor blades have aerodynamic performance capable of efficiently supplying high-temperature and high-pressure air to the combustor, so they are vital components to achieve high energy efficiency in next-generation combined gas turbines. Replacing conventional compressor blades from steel to titanium is expected to increase energy efficiency by about 0.1%, with an economic value of millions per year per gas turbine. Therefore, titanium compressor blades are applied to the recent gas turbines developed in overseas markets, which have the world's highest energy efficiency.

The technology developed by the research team is to manufacture 28-inch large compressor blades with high-strength titanium alloy (Ti-6Al-4V). It is significant since the entire life cycle process (melting→intermediate material→die forging→processing) from material production to parts manufacturing was achieved with technology independence, and the manufacturing value chain was created in Korea through purely domestic technology.

To manufacture the entire process from materials to parts with domestic infrastructure, the research team performed vacuum melting analysis and process design for heat treatment and made an effort to secure the reliability of domestic titanium blades through mechanical and chemical evaluation of products produced in each process. In particular, the research team increased the competitiveness of domestic products in terms of price competitiveness, delivery time, and quality improvement by connecting the value chain of each manufacturing process in Korea.

Recently, there has been a growing demand for improving the energy efficiency of combined gas turbines to respond to strengthened carbon dioxide emission regulations and reduce energy import dependence. To this end, it is necessary to increase the combustion temperature and pressure of the gas turbine, and increase the size of the turbine blades for this purpose. When manufactured to a large size, heat-resistant steel blades have a high possibility of part breakage during rotation due to increased weight, so the blade material is replaced with high-strength, lightweight titanium alloy. Currently, they are imported from overseas due to the lack of domestic technology and related infrastructure.

Korea is the world’s fifth country which developed its gas turbine model and is currently developing a combined gas turbine with 63% energy efficiency. The Korean government has announced a promotion strategy to become one of the world's top 4 gas turbine powerhouses by 2030. The product developed by the KIMS research team is in line with Korea's gas turbine development goals and is expected to contribute to developing of world-class gas turbines.

The principal investigator Dr. Sang-won Lee said, “For developing eco-friendly complex gas turbines, using titanium to enlarge gas turbine blades is a necessary technology. This technology is expected to have a great ripple effect as it can be quickly applied to the localization of production of large-sized titanium parts for national defense, aerospace, and space, which have been difficult to develop.”

This research was supported by the Ministry of Trade, Industry and Energy's material and parts technology development project (development of 1,250MPa high specific strength titanium alloy large blade manufacturing technology). The research team is conducting follow-up research to advance the timing of mass production of titanium blades and to improve product price, quality, and delivery competitiveness.