Turo, A.; Chavez-Dominguez, J. A.; Garcia, M.; Bulkai, A.; Tomek, P.; Tóth, G.; Girones, A.; Salazar, J. Measurement Vol. 46, num. 3, p. 1101-1108 DOI: 10.1016/j.measurement.2012.10.016 Data de publicació: 2013-04 Article en revista
The demand for powder metallurgy (P/M) parts in its traditional automotive market is predicted to grow, but future sector expansion depends directly upon its capability to manufacture zero-defect parts for industries such as aerospace and medicine. The lack of adequate inspection systems has important implications from the point of view of quality assurance, since it increases the costs, time and wasted material. In recent years the applicability of several techniques for the inspection of P/M parts has been investigated, such as Eddy current testing, computer tomography or X-ray imaging, but studies have revealed that all of them have deficiencies that make them unavailable for a complete and reliable flaw detection and density defect recognition. A new inspection tool has been developed based on pulse echo ultrasonic technology combined with robotics, which makes it possible to provide a global density map of sintered.
Duplex stainless steels configure a family of metallic alloys that combined elevated mechanical properties with improved corrosion resistance when compared to standard austenitic grades. This excellent combination of properties leads to their use under many different applications, particularly in the fields of chemical, petrochemical, pulp and paper industries. Moreover, these applications usually involve cyclic loading, and consequently the study of fatigue properties has a great significance for reliable design and safe-operation.
This chapter is devoted to study and analyze the cyclic deformation response of duplex stainless steels under standard testing conditions. The first point studied is the fatigue behavior of a duplex stainless steel corresponding to the last generation or superduplex. The cyclic stress-strain curve (CSSC) was determined through a wide interval of plastic strain amplitudes by incremental fatigue tests. Afterwards, constant total strain amplitude fatigue tests were performed at four different total strain amplitude values, values that correspond to marked different positions within the CSSC. TEM analysis of the different substructures developed within both constituent phases, i.e. austenite and ferrite, was done for each plastic strain amplitude. Finally, results obtained for the superduplex steel are compared to those reported for other duplex with lower nitrogen content tested under similar experimental conditions.
Girones, A.; Anglada, M.; Mateo, A. Journal of engineering materials and technology. Transactions of the ASME Vol. 129, num. 4, p. 588-593 DOI: 10.1115/1.2772325 Data de publicació: 2007-10 Article en revista
The corrosion fatigue performance of a superduplex stainless steel in two different chloride-bearing solutions (30g/l and 60g/lNaCl) is explored in the present paper. Fatigue life results and surface damage analysis show a strong influence of the applied strain amplitude, as well as of the chloride content, on the cyclic response. Moreover, there is an interaction between both factors because corrosion fatigue mechanisms at low and high strain amplitudes are not comparable, since ferrite is only fully plastically active at high strains. Whereas a detrimental effect of the 30g/lNaCl solution on the fatigue strength is observed, longer fatigue lives were attained in 60g/lNaCl solution, even longer than in air. Surface damage inspection and residual solutions analysis support a critical anodic dissolution rate, which would act as a polishing effect, as the main reason for this unexpected result.
Girones, A.; Llanes, L.; Anglada, M.; Mateo, A. Metallurgical and materials transactions A-Physical metallurgy and material Vol. 37A, num. 12, p. 3519-3530 DOI: 10.1007/s11661-006-1047-1 Data de publicació: 2006-12 Article en revista
Girones, A.; Villechaise, P.; Mateo, A.; Anglada, M.; Méndez, J. Materials science and engineering A. Structural materials properties microstructure and processing Vol. 387-389, num. 1-2, p. 516-521 DOI: 10.1016/j.msea.2004.01.105 Data de publicació: 2004-12 Article en revista