JOAO FRANKLIN LIBERATI
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Artigo IPEN-doc 11061 Grain Size of commercial high speed steel2005 - NOGUEIRA, R.A.; ARAUJO FILHO, O.O.; SOUZA, L.F.M.; LIBERATI, J.F.; SALGADO, L.; AMBROZIO FILHO, F.Artigo IPEN-doc 08230 Microstructure and corrosion resistance of simultaneous nitrided and sintered AiSi 434L powders1999 - TORO, A.; FALLEIROS, N.A.; RODRIGUES, D.; AMBROZIO FILHO, F.; LIBERATI, J.F.; TSCHIPTSCHIN, A.P.Artigo IPEN-doc 13563 P/M processing routes for high nityrogen martensitic stainless steels2002 - TORO, A.; ALONSO FALLEIROS, N.; RODRIGUEZ, D.; AMBROZIO FILHO, F.; LIBERATI, J.F.; TSCHIPTSCHIN, A.P.Artigo IPEN-doc 08233 Microstructure and corrosion resistance of simultaneous nitrided and sintered AISI 434L powder2001 - TORO, A.; FALLEIROS, N.A.; RODRIGUES, D.; AMBROZIO FILHO, F.; LIBERATI, J.F.; TSCHIPTSCHIN, A.P.Artigo IPEN-doc 13033 Low-pressure injection molding processing of AISI T15 high speed steel powders2006 - LIBERATI, JOAO F.; ARAUJO FILHO, OSCAR O.; MONTEIRO, WALDEMAR A.; ESPOSITO, IARA M.; NOGUEIRA, REJANE A.; AMBROZIO FILHO, FRANCISCOArtigo IPEN-doc 13034 Transverse rupture strenght of M3:2 high speed steel produced through conventional casting and powder metallurgy techniques2006 - ARAUJO FILHO, OSCAR O.; LIBERATI, JOAO F.; MONTEIRO, WALDEMAR A.; NEVES, MAURICIO D.; SILVA, LUIS C.E. da; AMBROZIO FILHO, FRANCISCOThe main aim of this work is to study the influence of the heat treatment on the transverse rupture strength of three M3:2 high speed steel obtained by differents techniques. PM Sinter 23 obtained by hot isostatic pressing (HIP) of gas atomized powders, a vacuum sintered high speed steel obtained by uniaxial cold compaction and liquid phase sintering of M3:2 water atomized powders and a conventional (cast to ingot and hot work) VWM3C were submitted to hardening in order to determine the influence of this treatment on the transverse rupture strength. The two PM high speed steels and the conventional one were submitted to heat treatment of hardening with austenitizing temperatures of 1140, 1160, 1180 and 1200 °C and tempering at 540 and 560 °C. The effectiveness of the heat treatment was determined by hardness tests (Rockwell C hardness). The microstructure was evaluated by scanning eletronic microscopy (SEM). At least five samples of these three high speed steels were manufactured, austenitized, quenched and tempered as described above and fractured in three point bending tests in order to evaluate the influence of this treatment on the transverse rupture strength (TRS).Artigo IPEN-doc 14563 Sintering of AISI M3:2 high speed steel - Part II2006 - ARAUJO FILHO, O.O.; NEVES, M.D.M.; LIBERATI, J.F.; SILVA, L.C.E. da; SALGADO, L.; AMBROZIO FILHO, F.Artigo IPEN-doc 14564 Grain size of commercial high speed steel2006 - NOGUEIRA, REJANE A.; ARAUJO FILHO, OSCAR O.; SOUZA, LEONARDO F.M.; LIBERATI, JOAO F.; SALGADO, LUCIO; AMBROZIO FILHO, FRANCISCOThe heat treatment of high speed steel tools consists of austenitizing, quenching and tempering. The size of austenite grains formed during the hardening treatment is an important factor in the final microstructure of the steel, and it also affects properties such as wear resistance and toughness. This paper presents the austenite grain size, matrix composition and hardness of commercial AISI M2, AISI T15, VWM3C and Sinter 23 high speed steels that were austenitized and quenched from five distinct temperatures. This study shows that increase in quenching temperature results in grain growth of steels such as AISI M2 and VWM3C, obtained by the conventional method (cast to ingot and worked). The P/M Sinter 23 high speed steel showed a slight grain growth (about 10%). This effect was not observed in AISI T15 obtained by the powder metallurgy process.