Hanhart combines two high-tech processes in the elaborate, multi-stage production of its HD12™ cases to preserve the fine details in the appearance of the case in addition to optimum scratch re-sistance. As a result, the new Preventor HD12™ not only has an ex-tremely hard surface, but also brushed, matt and glossy surfaces.

In a first step, large quantities of carbon are diffused into the stain-less steel in a surface hardening process. This creates a gradual transition from the hard surface to the soft core. This process offers an enormous advantage over a pure coating, as it prevents brittle-ness. A transparent hard coating (PVD) is then applied to provide additional protection.

With this process, the HD12™ steel achieves an impressive surface hardness of up to 1200 HV (Vickers hardness), which makes the watch case many times more resistant to scratches. In contrast, conventional 316L steel has a surface hardness of around 220 HV..