UltraGlow® Ion Nitriding is used in the automotive industry to surface harden stamping tools, which are usually made of cast steels or a variety of cast irons.
The tools subjected to very high stresses like those stamping the Advanced High-Strength Steels (AHSS), Dual Phase (DP), or Transformation Induced Plasticity (TRIP) steels are made of cast steels containing increased amount of chromium (up to 5%).
UltraGlow® Ion Nitriding significantly enhances the endurance and hardness of the die by eliminating adhesion of the die to the sheet steel product and reducing its scratching and scoring. In these applications, forming dies must be made of better materials to withstand more severe working conditions when used for forming high strength steels and dual phase sheet steels. It is essential for stamping tools to have a surface layer resistant to wear and contact fatigue.
Common practice is to UltraGlow® Ion Nitride dies that have high speed steel weld beads on the die in the most critical and stressed areas. High speed steels such as M-2 nitride very well, and if the case structure is controlled with sufficient precision, they offer great performance. UltraGlow® Ion Nitriding provides excellent control of the case structure. There is no compound zone and no evidence of nitrocarbide network at grain boundaries. Hardness of this layer is very high and can withstand almost any stress produced during forming of the AHSS sheet auto body parts.
In many situations, when the stamped steels are galvanized with zinc or zinc-iron coatings or when tools show excessive galling, the nitrided layer must have a comparatively thick compound zone formed of iron nitrides to improve anti-sticking properties of the tool surface. Stamping dies made of gray cast iron have to be UltraGlow® Ion Nitrided to maintain a superior surface finish. Surface of the gray cast iron dies is smooth after UltraGlow® Ion Nitriding and the compound zone is very compact without any cracks or delineation. Surfaces of this type can easily be finished to an A-class required for an excellent performance of the tool. Any attempt to gas nitride will result in a very rough surface.
Advanced Heat Treat Corp. can Ion / Plasma Nitride large stamping dies, with one of the largest vessels in the U.S.!