New tool steel in the high thermal conductivity tool steel series. It has extremely high thermal conductivity and good mechanical properties and can be applied to cross-sections with thicknesses exceeding 1000 mm. Due to its excellent thermal conductivity (twice that of traditional tool steel), elongation and extremely high polishing, it provides significant advantages for injecting plastics. By eliminating warpage and shrinkage marks, the construction period is shortened and the quality of parts is greatly improved.