Open Access
Influence of friction coefficient on the performance of cold forming tools
(MDPI, 2023) Barba Areso, Eneko; Salcedo Pérez, Daniel; Claver Alba, Adrián; Luri Irigoyen, Rodrigo; García Lorente, José Antonio; Ingeniería; Ingeniaritza
The automotive industry has undergone significant advancements and changes over time, resulting in the use of more complex parts in modern vehicles. As a consequence, the parts used in the manufacturing process are subject to higher stress levels, which reduce their service life. To mitigate this issue, surface treatments can be applied to improve the mechanical properties of the tools. In this study, we examined the impact of surface treatments on reducing tool stress during a cold forming process. The process involved reducing the thickness of a sheet from 6 mm to 2.5 mm, which generated high stresses in the tooling. We used finite element stress calculations to analyze the process and found that by reducing the friction coefficient to 0.1, tool stresses can be reduced by 20%, leading to an increase in tool life. Moreover, the press force and tool wear were also reduced by 18%. To validate the theoretical calculations, we performed field tests in a real manufacturing process.
Open Access
Biodegradable magnesium alloys for personalised temporary implants
(MDPI, 2023) Hendea, Radu Emil; Raducanu, Doina; Claver Alba, Adrián; García Lorente, José Antonio; Cojocaru, Vasile Danut; Nocivin, Anna; Stanciu, Doina; Serban, Nicolae; Ivanescu, Steliana; Trisca-Rusu, Corneliu; Campian, Radu Septimiu; Institute for Advanced Materials and Mathematics - INAMAT2
The objective of this experimental work was to examine and characterise the route for obtaining demonstrative temporary biodegradable personalised implants from the Mg alloy Mg10Zn-0.5Zr-0.8Ca (wt.%). This studied Mg alloy was obtained in its powder state using the mechanical alloying method, with shape and size characteristics suitable for ensuing 3D additive manufacturing using the SLM (selective laser melting) procedure. The SLM procedure was applied to various processing parameters. All obtained samples were characterised microstructurally (using XRD—Xray diffraction, and SEM—scanning electron microscopy); mechanically, by applying a compression test; and, finally, from a corrosion resistance viewpoint. Using the optimal test processing parameters, a few demonstrative temporary implants of small dimensions were made via the SLM method. Our conclusion is that mechanical alloying combined with SLM processing has good potential to manage 3D additive manufacturing for personalised temporary biodegradable implants of magnesium alloys. The compression tests show results closer to those of human bones compared to other potential metallic alloys. The applied corrosion test shows result comparable with that of the commercial magnesium alloy ZK60.
Open Access
Study and optimization of the punching process of steel using the Johnson-Cook damage model
(MDPI, 2024) Claver Alba, Adrián; Hernández Acosta, Andrea; Barba Areso, Eneko; Fuertes Bonel, Juan Pablo; Torres Salcedo, Alexia; García Lorente, José Antonio; Luri Irigoyen, Rodrigo; Salcedo Pérez, Daniel; Ingeniería; Ingeniaritza; Institute for Advanced Materials and Mathematics - INAMAT2
Sheet metal forming processes are widely used in applications such as those in the automotive or aerospace industries. Among them, punching is of great interest due to its high productivity and low operating cost. However, it is necessary to optimize these processes and adjust their parameters, such as clearance, shear force or tool geometry, to obtain the best finishes and minimize crack generation. Thus, the main objective of this research work is to optimize the punching process to achieve parts that do not require subsequent processes, such as deburring, by controlling the properties of the starting materials and with the help of tools such as design of experiments and simulations. In the present study, tensile tests were performed on three steels with different compositions and three sample geometries. The information obtained from these tests has allowed us to determine the parameters of the Johnson-Cook damage criteria. Moreover, punching was performed on real parts and compared with simulations to analyze the percentage of burnish surface. The results obtained show that the methodology used was correct and that it can be extrapolated to other types of die-cutting processes by reducing the percentage of surface fractures and predicting the appearance of cracks. Furthermore, it was observed that clearance has a greater influence than processing speed, while the minimum percentage of the burnish area was observed for the minimum values of clearance.
Open Access
Study of effect of nickel content on tribocorrosion behaviour of nickel-aluminium-bronzes (NABs)
(MDPI, 2023) Berlanga Labari, Carlos; Claver Alba, Adrián; Biezma Moraleda, María Victoria; Ingeniería; Ingeniaritza; Institute for Advanced Materials and Mathematics - INAMAT2
The simultaneous existence of mechanical erosion and electrochemical corrosion is a common scenario for engineering alloys used in marine environments, such as pump impellers and valves. Nickel–aluminium–bronzes (NABs) are widely used alloys in these environments due to their combination of high corrosion resistance and effective mechanical properties. However, NAB alloys are increasingly cast with reduced nickel content due to its high price and low availability. In this study, we examined the tribocorrosion behaviour of two nickel–aluminium bronzes (C95500 and C95400) with different nickel contents (4.8% and 1.0%, respectively) by means of a pin-on-disk device combined with in situ electrochemistry under 1 M NaCl solution. We conducted tests for pure wear in distilled water, pure corrosion using in situ electrochemistry under 1 M NaCl solution, and a combination of wear and corrosion, called tribocorrosion, to understand the overall synergism that exists between the two. We analysed our results using gravimetric as well as volumetric analysis; in addition, we defined the friction coefficient to compare the effect of open-circuit potential (OCP). We also applied the Tafel method and compared corrosion rates for the different scenarios. We employed confocal microscopy to delimitate the impact of the surface topography of pure wear and its synergistic effect with corrosion, and used an optical microscope to study the materials’ microstructures as cast conditions. We also utilised XRD in the Bragg–Brentano configuration to determine the chemical composition of corrosion products. From the experiments conducted, we concluded that an important synergistic effect existed between the wear and corrosion of both NABs, which was associated with corrosion-induced wear. We found NAB C95400 to be more susceptible to erosion under both conditions compared with NAB C95500 due to the chemical composition and lubricant effect of corrosion products formed during the tribocorrosion tests, which were supported by the enriched Ni corrosion products, particularly the presence of nickel-rich copper chloride, 3Cu3(CuNi)(OH)6CuCl2, in the C95500 alloy. We concluded that, because it increased the nickel content, the NAB alloy offered better wear and corrosion behaviour in sea water conditions due to its protective film nature.
Open Access
Study of the industrial application of diamond-like carbon coatings deposited on advanced tool steels
(MDPI, 2024) Barba Areso, Eneko; Claver Alba, Adrián; Montalá, Francesc; Luis Pérez, Carmelo Javier; Sala, Neus; Colominas, Carles; García Lorente, José Antonio; Ingeniería; Ingeniaritza
The utilization of diamond-like carbon (DLC) coatings has emerged as a promising strategy to enhance the performance, durability, and functionality of industrial tools and components. Recognized for their exceptional attributes such as hardness, wear resistance, low friction, and biocompatibility, DLC coatings have achieved widespread acclaim for their potential to improve the capabilities of tool steels for different applications. This present study shows a comprehensive investigation into the application of DLC coatings on a diverse range of tool steel substrates, encompassing 1.2379, 1.2358, Caldie, K340, HWS, and Vanadis 4. The main aim is to show the effects of DLC coatings on these substrates and to provide an in-depth analysis of their properties during forming processes. Furthermore, this study explores the practical utilization of DLC-coated tool steel components, with a particular focus on their role in cold forming dies. Additionally, the study reviews the application of duplex treatments involving plasma nitriding to enhance DLC coating performance. To sum up, this study pursues a threefold objective: to investigate DLC coatings’ performance on diverse tool steel substrates; to assess the potential for improvement through nitriding; and to evaluate the behavior of DLC coatings in the cold stamping of S235 steel, which is of great technological and industrial interest to the cold forging sector.
Embargo
Recubrimientos PVD HiPIMS y dúplex sobre aleaciones de Mg para aplicaciones biomédicas
(2024) Claver Alba, Adrián; García Lorente, José Antonio; Zalakain Iriazabal, Iñaki; Ingeniería; Ingeniaritza
Esta tesis doctoral explora el desarrollo de nuevas estrategias de recubrimiento mediante técnicas de Physical Vapor Deposition (PVD) y su combinación con otras como Plasma Electrolytic Oxidation (PEO) o sol-gel, con la finalidad de resolver este problema y permitir su aplicación en la industria biomédica.
Open Access
The Yeregui family (18th-twentieth century)
(Springer, 2023) Aginaga García, Jokin; Claver Alba, Adrián; Pintor Borobia, Jesús María; Iriarte Goñi, Xabier; Ingeniería; Ingeniaritza
Since their appearance in the Middle Ages, mechanical clocks and watches have been ingenious devices with complex assemblies of gears, cams and actuators, some of which have survived to the present day. Over the centuries, advances in mechanical engineering were applied to clockmaking, achieving clocks with ever-increasing precision. In the north of Navarre, the Yeregui family formed an outstanding family of mechanical clockmakers who, from the end of the eighteenth century until the middle of the twentieth century, designed, built, assembled and maintained tower clocks for five generations. Their first recorded clock was designed and assembled by José Francisco Yeregui Zabaleta for the village of Betelu and its deed dates from 15th April 1796. Subsequently, different members of the family manufactured numerous clocks for towns and cities in and around Navarre, including the old clock of Pamplona Town Hall, in operation for more than 150 years until 1991 and recently restored. This chapter briefly describes the most significant advances in mechanical clockmaking and delves into the history and work of the Yeregui clockmaking lineage.
Open Access
Corrosion and tribological performance of diamond-like carbon-coated ZK 60 magnesium alloy
(MDPI, 2023) Claver Alba, Adrián; Fernández, Iván; Santiago, José A.; Díaz-Rodríguez, Pablo; Panizo-Laiz, Miguel; Esparza Gorráiz, Joseba; García Fuentes, Gonzalo; Zalakain Iriazabal, Iñaki; García Lorente, José Antonio; Institute for Advanced Materials and Mathematics - INAMAT2
In this work, hydrogenated and hydrogen-free Diamond-Like Carbon (DLC) coatings were deposited into ZK60 magnesium alloy using the promising coating method High-Power Impulse Magnetron Sputtering (HiPIMS). CrC and WC were used as interlayers of the thin films, and their influence was studied. The structure and composition of the coatings were characterized using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and Raman spectroscopy. Tribological tests, scratch tests, and nanoindentation were performed to obtain information about the mechanical and tribological properties of the coatings. Finally, immersion and electrochemical tests were performed to evaluate the corrosion behavior of the samples. The results showed a homogeneous layer with improved wear resistance, toughness, and hardness in addition to good adhesion to the substrate of the ZK60 magnesium alloy. The hydrogenated DLC coating showed better results that the hydrogen-free thin layer, and relevant differences were observed depending on the interlayer. In this work, the improvement in the tribological and corrosive properties of Mg alloys was studied by using thin layers of DLC and different intermediate layers, achieving similar or even better wear and adhesion values than with thicker layers.