Surface treatment coating for high-tensile steel plate forming [Dramatically improves mold durability!]

At the commemorative ceremony for the Month of Foundry Materials held in November last year, organized by the Foundry Materials Center, the "High Durability Surface Treatment Technology for High-Temperature Press Molding Dies (KS-G)," jointly developed by Kobe Steel, our company, and our group company, Kams Co., Ltd., was awarded the Chairman's Prize of the Foundry Materials Association. While the adoption of high-strength steel sheets, which are important for reducing the weight of automobiles, is rapidly advancing, the short lifespan of the dies used to mold these high-strength steel sheets has become a problem. The "KS-G" received high praise for significantly contributing to the improvement of die lifespan. (Note) High-strength steel sheets: High tensile strength steel sheets aimed at weight reduction.

**Content Overview** Kobe Steel's subsidiary, Japan High-Frequency Steel, has developed a surface treatment technology that increases the durability of molds for automotive steel sheets by 4 to 5 times compared to conventional methods. As automotive steel sheets are being strengthened for weight reduction, the increased damage to molds has become a challenge. The new technology alleviates the impact on molds during the steel sheet forming process, allowing automotive companies to reduce the hassle of mold replacement and enhance production efficiency. Toyota Motor Corporation and Hino Motors have decided to adopt this technology. Toyota reportedly uses it for processing suspension components. A 10-micrometer film is formed on the mold surface using titanium-based or chromium-based materials. By reviewing the composition of the film material, the durability against heat and impact generated from the friction between the mold and the steel sheet has been improved. The overheating temperature during film formation is set at 450 degrees, which is over 500 degrees lower than conventional methods, thus minimizing mold distortion due to high temperatures. **Features of KS-G** - High surface pressure resistance → Possesses excellent surface resistance and does not break even under high surface pressure - Wear resistance → Does not wear even under harsh press forming conditions - Heat resistance → No degradation of film performance even at high temperatures - Dimensional characteristics → Pressing is possible as usual even with high-tensile materials exceeding 780 MPa