The increasing interest on magnesium alloys relies on their biocompatibility, bioabsorbility and especially on their mechanical properties. Due to these characteristics, magnesium alloys are becoming a promising solution to be used, as temporary implants. However, magnesium alloys must overcome their poor corrosion resistance. This article analyses the corrosion behaviour in phosphate-buffered saline solution of three commercial magnesium alloys (AZ31B, WE43 and ZM21) as well as the influence of fluoride treatment on their corrosion behaviour. It is shown that the corrosion rate of all the alloys is decreased by fluoride treatment. However, fluoride treatment affects each alloy differently.

The use of numerical simulations for tool tryout and process control is becoming increasingly prevalent. In this work, the deep drawing process of a car inner door panel of DC06 mild steel is numerically analyzed and compared with industrial process results. Five batches of DC06 material were analyzed mechanically and tribologically. Diverse tribological models were developed based on experimental strip drawing tests, where a Coefficient of Friction (CoF) was obtained as a function of contact pressure, sliding velocity, and amount of lubricant. A topography analysis was defined to compare material batches and to replicate industrial tool conditions. The simulation was fed with three tribological models: constant (CoF 0.15), Filzek pressure and velocity dependent, and TriboForm with lubrication zones. Thinning, Forming Limit Diagram (FLD) and draw-in were used as indicators for the comparison. Using the industrial tool, both FLD and draw-in were measured and compared with the numerical models. The constant model predicted the most conservative strain state and also differed most from the experimental results. The P-v-dependent and TriboForm models more accurately predicted the experimental results. This work highlights the importance of considering more complex tribological models to feed numerical simulations to yield results closer to real process conditions.

In a context where industrial production boosts both the society and the economy of a country, improvements in industrial processes are key factors for efficient and reliable development of goods and products. New industrial processes and machines must be evaluated before deployment at large production scales. This paper proposes a new optimized design and manufacturing methodology to develop scaled test benches under predefined design requirements and constraints. The main contribution of this paper is the integral scaling methodology based on an optimized dimensional analysis and a similitude metric that eases the design of a test bench. Thus, the search for the optimal physical magnitudes of the test bench is accelerated and the inability to design non-proportional components is solved avoiding distortion. The first step of the methodology is definition of scaling laws through the Buckinghams Pi theorem. The second step is to employ a constrained optimization to determine the physical magnitudes of the test bench, based on the scaling laws defined earlier. The third step is to calculate the parameter activities and to set the design tolerances of the scaled components, so that the components are designed more freely while dealing with non-proportional ratios obtained due to arbitrary constraints. The methodology was used to construct a test bench of a servo press that retains the kinematics and dynamics of an industrial servo press. Experimental assessment of the dynamic and kinematic similitudes showed a less than 5% deviation from the industrial servo presss force/angular position ratio.

The final quality of sheet and tube metal–formed components strongly depends on the tribology and friction conditions between the tools and the material to be formed. Furthermore, it has been recently demonstrated that friction is the numerical input parameter that has the biggest effect in the numerical models used for feasibility studies and process design. For these reasons, industrial dedicated software packages have introduced friction laws which are dependent on sliding velocity, contact pressure and sometimes strain suffered by the sheet, and currently, temperature dependency is being implemented as it has also a major effect on friction. In this work, three lubricants having different viscosity have been characterized using the tube-sliding test. The final aim of the study is to fit friction laws that are contact pressure and sliding velocity dependent for their use in tube hydroforming modeling. The tests performed at various contact pressures and velocities have demonstrated that viscosity has a major effect on friction. Experimental hydroforming tests using the three different lubricants have corroborated the importance of the lubricant in the final forming of a triangular shape. The measurement of the axial forces and the final principal strains of the formed tubes have shown the importance of using advanced friction laws to properly model the hydroforming process using the finite element modeling.