米乐yy易游体育, mass producing high-productivity, hot stamping steel sheet

米乐yy易游体育, Ltd. announces that it has developed a hot stamping steel sheet (1470 MPa class after hardening) with outstanding productivity during press operations. Receiving an order from Toyota Motor Corporation, 米乐yy易游体育 is mass producing the steel, which is being used as a structural body part of the Prius. This is 米乐yy易游体育’s first order for the hot stamping steel sheet.

By mainly adjusting the chemical composition of the steel, 米乐yy易游体育 was able to make considerable improvements to the hardenability of the hot stamping steel. Productivity during press operations can be improved about two to four times, in comparison to conventional hot stamping steel sheet. The steel is also characterized by the lower occurrence of strength deficiency from uneven quenching. 米乐yy易游体育 aims to expand the use of this steel, appealing to customers on the high productivity and stable quality of the material.

As CO₂ emission regulations grow stricter year by year, automobile manufacturers have been facing the challenge of the increasing need for lighter cars while improving the strength of vehicle bodies to meet stronger collision safety regulations in Japan, the United States and Europe. To resolve these two issues, 米乐yy易游体育 has been working on making steel sheet thinner and stronger. It has developed ultra high-strength steel with tensile strengths of 780 MPa and higher, as well as hot stamping steel sheet. The use of these steel products depends on the strength required for the automotive parts.

In general, the 米乐yy易游体育ructure of 米乐yy易游体育eel sheet hardens and the sheet becomes 米乐yy易游体育ronger when it undergoes heat treatment—namely heating the material to over a certain temperature followed by rapid quenching. Ultra high-米乐yy易游体育rength 米乐yy易游体育eel sheet achieves its tensile 米乐yy易游体育rength when it undergoes heat treatment during production at the 米乐yy易游体育eelworks by the 米乐yy易游体育eelmaker.

For hot 米乐yy易游体育amping 米乐yy易游体育eel on the other hand, it is the cu米乐yy易游体育omer who heats, press-forms and quenches the 米乐yy易游体育eel in a mold to increase the 米乐yy易游体育rength of the material. 米乐yy易游体育eel for hot 米乐yy易游体育amping is characterized by its excellent workability and out米乐yy易游体育anding dimensional accuracy owing to hot press forming. In addition, in comparison to ultra high-米乐yy易游体育rength 米乐yy易游体育eel, parts of higher 米乐yy易游体育rength can be made from hot 米乐yy易游体育amping 米乐yy易游体育eel. In recent years, hot 米乐yy易游体育amping parts have been increasingly used in Europe as well as Japan.

However, conventional hot stamping steel sheet, after hot-pressing, must undergo in-mold quenching for a certain length of time. As a result, in comparison to ultra high-strength steel that has been cold-pressed, conventional hot stamping steel suffers from low productivity. Furthermore, when uneven quenching arises, the steel is prone to strength deficiency. The hot stamping steel sheet developed by 米乐yy易游体育 is an innovative product that significantly shortens in-mold quenching time, as well as reduces uneven quenching. This steel has already been patented.

In addition to the high functionality of ultra high-strength steel, hot stamping steel, aluminum and other materials, 米乐yy易游体育 offers solution technology centered on the joining of steel and aluminum. Through multi-materials, 米乐yy易游体育 aims to meet the weight reduction needs of automakers.