Stamping Dies

Tools that are UltraGlow® Ion Nitrided can be used to form much stronger steels because they can endure higher contact stresses during metal forming.

NEW! Download our recent article published in Industrial Heating on Improving Performance of Stamping Dies with Ion/Plasma Nitriding! Click here.

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.

Stamping dies during UltraGlow® Ion Nitriding.

Checking the hardness on stamping dies after UltraGlow® Ion Nitriding.

The 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 as shown in Figure 1. 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 as demonstrated in Figure 2.

Fig 1: Photomicrograph of the GM350 gray cast iron sample under UltraGlow® Ion Nitriding at 1050°F. Etched with 2% nital.

Figure 2: Surface of the GM350 gray iron samples after UltraGlow® Ion Nitriding (Left). Surface of the GM350 gray iron samples after controlled Gas Nitriding (Right).

***Nitriding temperature of 1050°F and nitriding time of 15 hours were identical in both processes.

Click here to read about ion nitriding outperforming chrome plating when it comes to stamping dies, and read our technical papers on stamping dies here.

Looking for even more information on the heat treatment of stamping dies? Request an on-site technical presentation!

Quick Contact