At 58-60 HRC, Bohler-Uddeholm’s Caldie is the toughest tool steel that the company carries, and that toughness is said to make it a suitable substitute for S7 applications such as smaller molds, core pins, cores and cavities.
Caldie is produced using electro-slag remelting (ESR), which accounts for its higher hardness, improved resistance to high-wear resins and better polishing properties. In addition, this material can withstand higher tempering temperatures and can be PVD-coated for increased tool life. It can be coated as high as 950°F without deterioration in properties or stability, the company says.
Editor's PickPre-hardened Mold Steel Machines Faster Than P20
NAK 80 from International Mold Steel and Daido Steel is a pre-hardened mold steel (38-42 HRC) designed to be machined 10-15 percent faster than P20 steel.