18 documents found, page 1 of 2
Microstructural changes produced by plastic deformation in the UNS S31803 duple...
Tavares, Sérgio Souto Maior; Silva, Manoel Ribeiro da; Pardal, Juan Manuel; Abreu, Hamilton Ferreira Gomes de; Gomes, Angelo Márcio de SouzaPlastic deformation by cold rolling produces important changes on microstructure of the duplex stainless steel UNS S31803. Structure refinement and martensitic transformation were detected and analyzed by microscopy, X-ray diffraction and magnetic measurements. True deformations in the range of 0.92–3.38 were applied. The maximum amount of ′ martensite was 30.2% obtained with the maximum deformation applied (3....
Deleterious Phases Precipitation on Superduplex Stainless Steel UNS S32750: Cha...
Pardal, Juan Manuel; Tavares, Sérgio Souto Maior; Fonseca, Maria da Penha Cindra; Souza, José Adailson de; Vieira, Lorena MenezesDeleterious phases precipitation in superduplex stainless steels is the main concern in fabrication by welding and hot forming of this class of material. Sigma, chi and secondary austenite phases are considered deleterious phases because they produce negative effects on corrosion resistance. Besides, sigma and chi phases also promote strong decrease of toughness. In the present work, the precipitations of sigma...
Tensile Properties of Duplex UNS S32205 and Lean Duplex UNS S32304 Steels and t...
Tavares, Sérgio Souto Maior; Pardal, Juan Manuel; Abreu, Hamilton Ferreira Gomes de; Nunes, Cristiana dos Santos; Silva, Manoel Ribeiro daDuplex stainless steels are high strength and corrosion resistant steels extensively used in the petrochemical and chemical industries. The aging at 475 °C for long periods of time provokes embrittlement and deterioration of corrosion resistance. However, short duration aging at 475 °C may be used as heat treatment to improve mechanical resistance with small decrease in the other properties. In this work the fl...
The effect of prior austenite grain size on hydrogen embrittlement of Cocontain...
Silva, Marcelo José Gomes da; Cardoso, Jorge Luiz; Carvalho, Dayane de Sousa; Santos, Luis Paulo Mourão dos; Herculano, Luís Flávio GasparThe effects of the prior austenite grain sizes in hydrogen embrittlement of Co-containing 18Ni 300 maraging steel were studied employing Slow Strain Rate Testing (SSRT) in 0.6 M NaCl electrolyte under simultaneuos cathodic polarization. The material was susceptible to hydrogen embrittlement in all investigated conditions. In addition, the examination of the fractured surface revealed that the presence of hydrog...
Influence of carbon content on the martensitic transformation of titanium stabi...
Pardal, Juan Manuel; Tavares, Sérgio Souto Maior; Tavares, Mauro Teixeira; Garcia, Pedro Soucasaux Pires; Velasco, Javier Alejandro CarrenoAustenitic stainless steels (ASS) are corrosion resistant alloys in which the desirable mechanical properties may be attained by cold working in the final stages of the fabrication process. This manufacturing process may induce martensitic transformation from the austenitic phase, where the chemical composition plays an important role as it influences the stacking fault energy (SFE). Therefore, this work evalua...
EBSD study of early fractured phenomena in a 350 grade Maraging steel elbows ex...
Masoumi, Mohammad; Abreu, Hamilton Ferreira Gomes de; Herculano, Luís Flávio Gaspar; Pardal, Juan Manuel; Tavares, Sérgio S.M.; Silva, Marcelo J.G.The effect of grain orientations, boundary characteristics, and crystal effects on the crack formation of a 350 high strength Maraging steel elbows exposed to hydrofluoric acid was investigated in the present research. Tempered low tetragonal martensite and fresh martensite were characterized by scanning electron microcopy. Moreover, no segregation zone and precipitates were found near the crack path. Detail an...
The role of microstructure and grain orientations on intergranular cracking sus...
Masoumi, Mohammad; Tavares, Sérgio Souto Maior; Pardal, Juan Manuel; Martins, Tabatta Regihna Brito; Silva, Marcelo José Gomes daThe aim of this work was to investigate the role of crystallographic orientations and grain boundary characteristics as a new approach to controlling the intergranular cracking (IGC) susceptibility. In this respect, hydrogen cathodic charging under two different current densities was carried out on 17–4 pH steel (H900 condition) in order to search for correlations between intergranular corrosion and microstruct...
Degradation of mechanical and corrosion resistance properties of AISI 317L stee...
Farneze, Humberto Nogueira; Tavares, Sérgio Souto Maior; Pardal, Juan Manuel; Nascimento, R.F. do; Abreu, Hamilton Ferreira Gomes deThe use of austenitic stainless steel type AISI 317L has increased in the last years, in substitution to AISI 316L and other austenitic grades. The higher Mo content (3.0 wt.%. at least) gives higher corrosion resistance to AISI 317L. However, some concern arises when this material is selected to high temperature process services in refineries. Microstructural changes such as chromium carbide precipitation and ...
Influence of heat treatments on toughness and sensitization of a Ti-alloyed sup...
Silva, G. F. da; Tavares, S. S. M.; Pardal, Juan Manuel; Silva, M. R.; Abreu, Hamilton Ferreira Gomes deSupermartensitic steels are a new class of martensitic stainless steels developed to obtain higher corrosion resistance and better toughness through the reduction of carbon content, and addition of Ni and Mo. They were developed to more critical applications or to improve the performance obtained with conventional grades AISI 410, 420, and 431. In this study, the influences of the tempering parameters on the mi...
Deleterious phases precipitation on superduplex stainless steel UNS S32750: cha...
Pardal, Juan Manuel; Tavares, Sérgio Souto Maior; Fonseca, Maria da Penha Cindra; Souza, José Adailson de; Vieira, Lorena MenezesDeleterious phases precipitation in superduplex stainless steels is the main concern in fabrication by welding and hot forming of this class of material. Sigma, chi and secondary austenite phases are considered deleterious phases because they produce negative effects on corrosion resistance. Besides, sigma and chi phases also promote strong decrease of toughness. In the present work, the precipitations of sigma...