Garikoitz Artola

AZTERLAN (BRTA)

The effect of the microstructure on the corrosion resistance of four grades of cast irons was studied in an alkaline 0.03 M NaCl solution. The research was performed by combining microstructural analysis, electrochemical measurements and the characterization of the corroded surfaces. The structure underneath the corrosion layer determines the corro...

A multilayer laser-deposited lining of AISI 316L stainless steel makes a regular structural steel surface corrosion resistant in physiological media. Despite the application of single-layer stainless-steel linings being economically beneficial and allowing thinner surface modifications, dilution effects that modify the pitting resistance of the coa...

Today's huge automotive industry requires continuous innovations. In this sense, numerous publications on new materials or developments which can provide new weight reductions or safety improvements are released every day. An important example is hot stamping, which has been gaining popularity in the last years due to its advantages for the sector....

Antifragile philosophy can be the key to improving the management of organizations that base their activity on research and development (R&D) projects. These are types of projects with the greatest uncertainty in all aspects, and the application of antifragile philosophy can result in streamlining their management and development. In this article,...

Cast iron and forged steel have competed against each other for many years for different industrial applications. Crankshafts are one of the products where this competition is still active, both for heavy duty and light machinery applications. For the specific case of automotive crankshafts, high strength pearlitic cast iron grades have found a str...

In the present climate led by industry and digital manufacturing, the implementation of intelligent tooling in manufacturing processes has become imperative. In the case of metal forming processes, this requirement is translated into controlling the material flow and the temperature in the tool-part contact interface. In this manner, not only the m...

Se han observado distintos patrones de agrietamiento inducido por hidrógeno en dos aceros pertenecientes al mismo grado para el fondeo de estructuras offshore, cuando son ensayados a tracción a baja velocidad de deformación. Se plantea la hipótesis de que este comportamiento se debe a diferencias en la capacidad de atrape de hidrógeno de ambos acer...

Hot stamping technology has shown a significant scientific yield in the last decade. The research activity in that field has spread across several disciplines such as materials science, mechanics, process engineering, instrumentation, physics, or part-tool design engineering. Some recent publications have gathered this richness in the format of sci...

The aim of this work is to develop a die material selection criterion for aluminum hot stamping applications. The criterion has been based on the back-to-back comparison of a set of reciprocating friction and wear tests. Three representatives belonging to different stamping die material families have been selected for the study: a cold work steel,...

When steel components fail in service due to the intervention of hydrogen assisted cracking, discussion of the root cause arises. The failure is frequently blamed on component design, working conditions, the manufacturing process, or the raw material. This work studies the influence of quench and tempering and hot-dip galvanizing on the hydrogen em...

Chunky graphite appears easily in heavy-section spheroidal graphite cast irons and is known to affect their mechanical properties. A dedicated experiment has been developed to study the effect of the most important chemical variables reported to change the amount of chunky graphite, namely the content in silicon and in rare earths. Quite unexpected...

Any manufacturing equipment designed from scratch requires a detailed follow-up of the performance for the first units placed in service during the production ramp-up, so that lessons learned are immediately implemented in next deliveries and running equipment is accordingly updated. Component failure analysis is one of the most valuable sources of...

Taking advantage of the residual heat in forged components right after forging, by means of loading them directly into a continuous heat treatment furnace, is a known strategy to improve energy efficiency. Besides energy savings, several side benefits are also achieved by this strategy, such as the capability of treating parts as individuals instea...

The high hardness property of hot working steel is not always an advantage as several defects can occur, which reduce the productivity and reliability of the hot forming processes. In the case of laser cladding technologies employed during deposition, porosity can appear in the clad material. In the current study, different strategies are explored...

Several vehicle platforms involving the hot stamping of manufactured parts are launched every year. Mass production represents a key step in the manufacturing process of an actual hot stamping part. In this step, the cycle time (consisting of cooling time (t1) and handling time (t2) components) must be optimized. During t1, the stamping tool (punch...

The aim of this work is to evaluate the microstructural evolutions developed by mixing a corrosion-resistant and high-performance material with a high-hardness material in a coating obtained by laser-cladding technology. In this paper, five different mixtures of Inconel 625 alloy and AISI H13 steel powders have been deposited on a plate of 42CrMo4...

Hydrogen embrittlement susceptibility ratios calculated from slow strain rate tensile tests have been employed to study the response of three high-strength mooring steels in cold and warm synthetic seawater. The selected nominal testing temperatures have been 3 °C and 23 °C in order to resemble sea sites of offshore platform installation interest,...

Most high-hardness tool steels comprising forming dies require expensive finish machining operations to compensate for the dimensional distortion and surface oxidation caused by the die heat treatment. Precipitation-hardening (PH) tool steels allow for soft finish machining followed by an aging treatment without major deformation or oxidation in th...

Stamping dies perform two functions in the hot stamping process of body-in-white components. Firstly, they form the steel sheet into the desired shape and, secondly, they quench the steel at a cooling rate that leads to hardening by means of the austenite-γ to martensite transformation. This microstructural change implies a volume expansion that sh...

The aim of this work is to investigate the durability of tool steels for hot stamping by comparing the wear resistance of three hot work tool steels. Friction and wear behaviours of different tool steels sliding against a 22MnB5 uncoated steel at elevated temperatures were investigated using a high-temperature version of the Optimol SRV reciprocati...

Although treatments at cryogenic temperatures have been known for decades, these processes are still far from being common in industry. This can be blamed to a great extent on insufficient understanding of the permanent effects caused by low temperatures in the materials. Many of the applications of cryogenic treatments have been developed empirica...

Austempered ductile iron (ADI) grades are standardized, and the requirements of current international standards (EN 1564-12/ASTM A897-15) are given terms of conventional mechanical properties, such as hardness and tensile strength. Nevertheless, these properties do not show the real potential of the ADI grades. In order to promote the use of ADI pa...

Foundry sector, as a whole, has incorporated relevant technological advances into productive processes. Nevertheless, the specific field of feeding system design criteria hasn’t improved in the same proportion. The use of simulation tools doesn’t always come together with the optimization of key indicators. Part rework costs remain unchanged, yield...

ADI grades are standardized and the requirements of current international standards (EN 1564-12 / ASTM A897-15) are given in terms of conventional mechanical properties. Nevertheless, these properties don’t show the real potential of the ADI grades. In order to promote the use of ADI parts in place of other materials, this work proposes a compariso...

Cryogenic treatments have shown a remarkable potential for improving the in-service performance of many tool steels despite the lack of knowledge to which this technology is associated and the poor understanding of its metallurgical fundamentals. The type of cryogenic treatment used and its position in the heat treatment sequence have a determinant...

Nearly all cast parts must undergo a machining process in order to be used in service. This work is exclusively targeted to spheroidal iron casting Grades that are demanded by the automotive industry, due to the intense machining operations that are performed on them. Chip removal processes on ferritic-pearlitic cast irons suffer from frequent inci...

Melt treatment of aluminium alloys is essential for optimizing their mechanical properties. Thermal analysis methods usually used as control are based on the cooling of the metal in metallic or sand cups. In investment casting, however, cooling takes place in a refractory mould at high temperatures (400-700 °C), where parts are characterized by thi...

When silicone is used as de-moulding agent for injected wax patterns, proper degreasing is needed to remove the silicon and produce micro-etching on the surface of the pattern. As the solvent starts enriching in the solute, the effectiveness of the etching is reduced leading to poor degreasing or etching that produces poor primary shell coat adhesi...

At present, milling of titanium based alloys for aerospace applications is mainly carried out with un-coated WC-Co carbide tools. The present work evaluates the chemical interaction of the Ti-6%Al-4%V alloy with these WC-Co commercial hardmetals. Strong decarburation induced by carbon diffusion to the Ti based alloy is observed at temperatures rang...