Zone induction hardened chrome plated bars

In the production process of chrome-plated and induction-hardened steel bars, it is frequently necessary to cut the material to size for subsequent mechanical processing, generally concentrated at the ends of the workpiece. However, the high surface hardness resulting from induction hardening can make these operations complex.
To avoid the problem, MODERCROMO applies a selective induction hardening technology involving the alternation, along the axis of the bar, of heat-treated zones and zones left in the rough state. In this way, the portions intended for processing —usually the ends — remain free from induction hardening and therefore easily machinable, while ensuring the mechanical performance required in the functional areas.
Applying this solution requires prior knowledge of the design of the finished parts, in order to correctly plan the distribution of the treated areas on the bar and optimize the use of the material.

From a metallurgical point of view, zone induction hardening represents a superior solution compared to localized annealing performed after induction quenching. This technique is applied before chrome plating treatment, ensuring more precise control over the material structure.
Once chrome plating is complete, the unhardened areas are no longer visible externally. Therefore, it is essential to leave a visual reference (engraving) at the cutting section. Furthermore, in case the ends to be machined have different lengths, an identification marking is applied to distinguish the longest part.
The permissible tolerance on the length of unhardened zones is +10 mm / -0 mm, ensuring precision and repeatability in the process.
It is important to emphasize that this treatment does not alter the geometric characteristics of the bar or compromise the quality of the chrome coating, thus maintaining the high technical standards required by MODERCROMO.