High-strength earthquake-resistant steel bars with strength levels of 600MPa and above are mainly used for the main load-bearing components of large and super-high-rise buildings. They have the characteristics of saving steel, convenient construction, large strength reserves, and improving the safety of building structures. They are high-strength, green, and environmentally friendly products encouraged by the state to promote and apply.

To further enhance the innovation and market competitiveness of Kunsteel's high-strength earthquake-resistant steel bars and expand the sales channels of earthquake-resistant steel bars, Kunsteel's Manufacturing Management Department (Technical Center) cooperated with the Marketing Center, Steelmaking Plant, and Rolling Mill to carry out the research and development of 650MPa high-strength earthquake-resistant steel bars. The project team has formulated a detailed process control plan for the aspects of composition design, smelting, casting, billet heating, rolling, etc., and strictly controls the production process. Finally, Kunsteel successfully developed 650MPa high-strength earthquake-resistant steel bars for the first time in the southwest region, achieving the optimal match of "chemical composition-smelting and pouring-billet heating and rolling-organization and performance regulation" of steel bars. The steel yield strength of 650MPa high-strength earthquake-resistant steel bars is 660MPa-680MPa, and its strength-to-yield ratio, maximum force total elongation, and other indicators meet and exceed the relevant standards for earthquake-resistant steel bars.

The successful development of 650MPa high-strength earthquake-resistant steel bars has significantly improved the technical innovation and market competitiveness of Kunming Steel's high-strength earthquake-resistant steel bars. In the next step, the Manufacturing Department (Technical Center) will lead the steelmaking plant and rolling mill to increase the research, development, and production of 650MPa high-strength earthquake-resistant steel bars and continue to maintain Kunming Steel's leading edge in this field.