MARCO ANTONIO COLOSIO

MARCO ANTONIO COLOSIO

Página do item completo

Resultados de Busca

Agora exibindo 1 - 7 de 7

The use of scanning vibrating electrode technique to evaluate the effect of hot stamping on corrosion resistance of press hardened steel 22MnB5 metallic coated with electroplated ZnNi
2018 - COUTO, C.P.; COSTA, I.; VIVEIROS, B.G. de; ALENCAR, M.C.; PANOSSIAN, Z.; ROSSI, J.L.; COLOSIO, M.A.
The carmakers and all their production chain must achieve worldwide targets of lightweight, safety and reduced fuel consumption. The use of ultra high strength steel, such as press-hardened steels (PHS), in vehicle structures has been contributing with this. This type of steel is widely used in hot stamping process, which consists in heating the steel blank to the total austenitization temperature, and then transferring it from the furnace into the die where the steel is deformed and quenched at the same time, with a minimum cooling rate of 27 K/s. The boron-manganese PHS steel comprises perlite and ferrite microstructure, and its tensile strength is around 600 MPa in the annealed condition. Thus, after the hot stamping process the PHS microstructure completely changes to martensite and the tensile strength increases to 1500 MPa or more. The transferring step is a critical one, due to the contact of the hot steel blank with the atmospheric air; as consequence, it causes the steel oxidation. To avoid that, the steel is protected with metallic coatings. The hot-dip AlSi is the most currently used coating for this application, however, in order to keep up with the high PHS demand, alternative coatings, like zinc-base is under investigation. This work had the objective of evaluating the corrosion resistance of PHS, 22MnB5 grade, coated with electroplated ZnNi before and after hot stamping, using scanning vibrating electrode technique (SVET). The corrosion-localized techniques are more suitable, once the results showed that after hot stamping the coating layer changes completely, as a result of chemical elements diffusion. Thus, different phases of Zn-Fe-Ni are formed and random distributed which impacts the corrosion resistance of the steel.
Heat treatment and characterization of sintered high-speed steel for valve seat insert application
2016 - GOMES, M.P.; ROSSI, J.L.; MUCSI, C.S.; SANTOS, I.P.; COLOSIO, M.A.; BETINI, E.G.
The aim of this work was the characterization of valve seat inserts (VSI) subjected to heat treatments. The VSI were produced with three different alloys modified from the AISI M3:2, M2 and D2. These alloys modifications were intended as an alternative to replace cobalt and lead used in the original alloy due to their high cost and toxicological effect. The VSI were submitted to different heat treatments, such as: air quenching and oil quenching, both followed by double tempering with different temperatures. The VSI mechanical and metallurgical properties were performed according to standardized apparent density (ASTM C 373-88), apparent hardness (ASTM E 92-82) and radial crush strength (MPIF Standard 35) tests. The VSI characterizations also were carried out using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and light optical microscopy (LOM). The VSI produced with alloy M3/2 showed the best results in the hardness test and radial crush strength.
Avaliação das tensões residuais do processo de fundição no comportamento físico de um disco de freio
2015 - TIRELLI, MARCELO A.; COLOSIO, MARCO A.; STUEWE, LUCIANA; ROLA, FABIO; ROSSI, JESUALDO L.
Materiais padrao de referencia para difratometria de po de raios X, radiacao sincrotron e neutrons
2010 - MARTINEZ, L.G.; GALVAO, A.S.; ORLANDO, M.T.D.; CORREA, H.P.S.; ROSSI, J.L.; COLOSIO, M.A.; SANTOS, J.C.
Extensometria aplicada a medidas de tensões residuais em rodas de aluminio
2012 - CIONI, F.C.; POLITANO, R.; SOUZA, A.C.; DELIJAICOV, S.; COLOSIO, M.A.; ROSSI, J.L.
Residual stresses measurements using strin gages applied to aluminium wheels
2011 - CEONI, F.C.; SANTOS, J.C.; COLOSIO, M.A.; CARMIGNOTTO, M.A.P.; PEREIRA, A.A.P.; SOUZA, A.C.; ROSSI, J.L.
Residual stresses measurements using strain gages - aluminium wheels
2012 - CIONE, F.C.; ROSSI, J.L.; SOUZA, A.C.; DELIJAICOV, S.; COLOSIO, M.A.