Each forging process is in its own way unique and may show different damage mechanisms. The majority of die failures are attributed to abrasive wear [
8‐
12] and only marginally to plastic deformation, thermomechanical fatigue cracks or fracture initiation caused by incorrect thermochemical treatments. Kim et al. [
13] developed a method for estimating die life based on the most commonly encountered phenomena, i.e. wear and plastic deformation, the latter being aggravated by a strength reduction caused by high temperature. However, experimental evidence divided the opinion of researchers on this issue. Kchaou et al. [
14] state that, given the wide variety of cases, different phenomena can be detected as the most severe. It depends on the situation and the geometry of the die has a considerable influence on the type of damage [
15]: the lateral surfaces of the die are subject to fatigue damage; with respect to the direction of deformation, both normal and tangential surfaces are affected by mechanical fatigue and wear, but the latter are more prone to deep cracks. Kchaou’s results are also supported by those of Behrens and Schaefer [
16], who determined a predictive model for the life of a die that depends on its hardness and geometry, and demonstrates the strong dependence of wear on contact conditions. A similar study, with a focus on the dependence of wear on geometric parameters, was also conducted by Davoudi et al. [
17] who revealed that increasing the surface angle not only does not improve the wear life of the die but also makes the wear deeper due to more severe conditions with high pressure and temperature. The studies carried out by Gronostajski et al. [
10,
18] raise strong doubts on whether dies deteriorate due to a single predominant effect; on the contrary, they state that more phenomena occur simultaneously during the process and that they interact with each other creating a chain action that complicates the identification of a wear model. In order to decouple the phenomena and to study them individually, M. Hawryluk et al. [
11] purposely built a test station; they assessed that thermomechanical fatigue and oxidation often appear concurrently and act synergically leading to abrasive wear, which is the most easily measurable phenomenon. In order to simplify the problem, one could therefore narrow down the field to the most significant factors [
19]. It is also helpful to assess the role of process temperature, which can influence a number of factors: a deviation in the initial temperature of the billet can lead to greater wear due to abrasion or plastic deformation and a hotter surface favours a reduction in the hardness of the die [
20,
21]. Tanaka et al. [
22] derived a correlation model of die temperature and wear by means of a cooling model that considers the Reynolds number of the lubricant jets. It is the lubricant itself, with its application time and temperature, that plays a key role in promoting the formation of a homogeneous and effective layer that can reduce the risk of heat cracking and surface softening [
23]. Safeguarding the microstructure and surface integrity is therefore extremely important for prolonging the life of the die. To this end, besides the classical nitriding treatment, special coatings and die processing techniques are being investigated [
24]. For example, Behrens et al. [
25] added a layer of nano-sized ceramic particles to a fine-grained microstructure to increase strength, ductility, fatigue and wear resistance without affecting surface friction. Gronostajski et al. [
12,
15] also tested different types of surface coatings in order to assess, also with the use of 3D scanner and hardness tests, which of them showed the best behaviour against damage mechanisms. Moreover, in relation to the surface integrity of the die and the degradation of the coating layer due to advancing wear, Behrens et al. [
26] developed a method for calculating the die life as a function of the surface hardness of the die. Among the die production methods, EDM has proved to be the most valid for the surface resistance results obtained: thanks to the martensitic microstructure reinforced with extremely hard iron carbides and the lower presence of surface defects compared to cutting processes, it offers excellent resistance to wear; failure, in this case, is due to the underlying layer that softens with repeated high-temperature cycles [
27]. In the first phase of use of the die, therefore, it can be assumed that the weakening effect due to thermal cycles is secondary to wear (the latter acts immediately while several cycles are needed before the microstructure is significantly altered). This behaviour motivated the study by Kim and Choi [
28], which consists of determining a wear model by quantifying the volume of material removed from the test profiles and comparing it with numerical simulations (as in Andersson et al. [
29]) and supporting it with fatigue stress analysis. The state of the art shows that it is possible to model die wear, but it is very difficult to consider the interrelations of the multiple damage phenomena involved (wear, plasticity, fatigue, fracture) and also of the many process parameters, which vary from one study to another and are difficult to compare. As the final objective of process designers is not the individuation of correlations among parameters but the optimization of die life, present paper proposes a numerical approach, corroborated by experimental evidence from an actual industrial processes, which take into account the only parameters that can be modified by the designer. Present method substitute the prediction of damage on the die with a sensitivity analysis that allows to search for an optimal configuration of process parameters that lead to the maximization of die life giving up knowing its exact value.