Modera Tool Steels for Long Life Time in Hot Stamping Application

摘要

Hot stamping, including tailored tempering, is a highly efficient technology to produce high-strength car components. The process therefore requires tools with high mechanical properties such as compression strength, hardness, abrasive wear resistance and thermal conductivity to insure an outstanding performance. In the past, the focus of research was on the thermal conductivity in order to reduce cycling time and to achieve a martensitic microstructure. Considering the distance between cooling channel and tool surface has reduced significantly from approx. 25 mm to 6-10 mm in the last few years, the high thermal conductivity is no longer the key property of tools. As a matter of fact, the requirement of higher hardness of tools increased rapidly. The increasing hardness improves the wear resistance and furthermore increases the tool lifetime consequently. In Europe, instead of standard steels 1.2367, also CR7V-L is been used in wild range due to its high hardness and high wear resistance. Based on the success of CR7V-L and to adjust the market demand, Kind & Co developed recently a special tool steel HS1 especially for hot stamping application which shows higher hardness and higher wear resistance compared with the common tool steels on the market. In this report, the properties of the tool steel HS 1 for hot stamping process will be described firstly. The tool steels, which are suitable for tailored tempering process will be introduced subsequently. Finally risks about stress induced corrosion in the cooling channel will be discussed.