Abstract The article reviews the metallurgical processes used in the first industrial ironworks operated in Brazil, the Patriótica Iron Factory, from 1812 to 1831. It discusses its impact on the ironmaking plants that spread in Minas Gerais's state during the XIX century. The remnants of this Factory in Ouro Preto were the first industrial site listed by the Brazilian Historic Heritage Authority (SPHAN) in 1938. Vale SA, owner of the site, and the National Historic and Artistic Heritage Institute (IPHAN) authorised collecting samples from two ferrous artefacts found in the old Factory, a hammer and an eyebolt nailed to the remnants of one of the reduction furnaces. The eyebolt’s microstructure suggests that this part was produced in the Patriótica Iron Factory, while the hammer’s microstructure indicates that this component was not produced in the Patriótica Iron Factory.

Abstract The microstructure of the main structural elements (Phoenix columns, transversal beams and tie-rods) of the Simón Bolivar iron bridge, located in Arequipa (Peru), was investigated. The bridge was supposedly designed by Gustave Eiffel and opened to the public in 1882. The characterisation revealed that the columns, beams and tie-rods are made of puddled iron (ferritic matrix of equiaxial grains and numerous slag inclusions). The tensile properties were estimated by hardness and nanohardness measurements, and the tensile strength varied between 285 and 390 MPa and the Young's modulus from 187 to 198 GPa. The components of puddled iron with the same provenance, Phoenix Iron Company, showed typical variations in the chemical composition and microstructure of the slag inclusions. The microanalysis results of the slag inclusions indicated that the wüstite phase presented qualitatively the same composition with pronounced variations in the ratio between V2O5 and TiO2 contents, confirming that a single parameter cannot be used to determine the provenance of iron artefacts. The intense presence of slag inclusions in the puddled iron components (~ 10% in volume fraction) heterogeneously distributed in the iron illustrates the technological limits of the iron refining technique of the time.

In this study the magnetic aging effect on anomalous and hysteresis loss was investigated, as well as its effect on domain morphology. For this purpose, non-oriented fully processed electrical steel with 2.3 wt.%Si - 79 ppm C and non-oriented semi-processed electrical steel annealed at 750 °C for 5 hours with 0.4 wt.%Si - 340 ppm C were aged at 150 °C. The anomalous loss has been shown to be less affected by the magnetic aging. The increasing of the excitation frequency has induced a reduction on anomalous loss measured on aged steel. All increases presented by total loss were provided by hysteresis loss. The main disturbance in magnetic domain morphology appears to have been caused by different grain orientation.

Microstructural characterization techniques, including EDX (Energy Dispersive X-ray Analysis) microanalyses, were used to investigate the slag inclusions in the microstructure of ferrous artifacts of the Royal Iron Factory of São João de Ipanema (first steel plant of Brazil, XIX century), the D. Pedro II Bridge (located in Bahia, assembled in XIX century and produced in Scotland) and the archaeological sites of São Miguel de Missões (Rio Grande do Sul, Brazil, production site of iron artifacts, the XVIII century) and Afonso Sardinha (São Paulo, Brazil production site of iron artifacts, XVI century). The microanalyses results of the main microconstituents of the microstructure of the slag inclusions were investigated by hierarchical cluster analysis and the dendrogram with the microanalyses results of the wüstite phase (using as critical variables the contents of MnO, MgO, Al2O3, V2O5 and TiO2) allowed the identification of four clusters, which successfully represented the samples of the four investigated sites (Ipanema, Sardinha, Missões and Bahia). Finally, the comparatively low volumetric fraction of slag inclusions in the samples of Ipanema (~1%) suggested the existence of technological expertise at the ironmaking processing in the Royal Iron Factory of São João de Ipanema.

ResumoA presente investigação analisou artefatos de ferro coletados em dois sítios arqueológicos na Montanha de Araçoaiaba. Uma metodologia conhecida foi adaptada para investigar várias amostras coletadas na Real Fábrica de Ferro de São João do Ipanema e no sítio de Sardinha. Resultados de microanálise EDX de inclusões não metálicas foram inseridos em gráficos bivariantes. Regressão linear (com e sem a restrição de intersecção pela origem) e testes de significância do intercepto da reta foram usados para interpretar esses resultados. Essa análise não permitiu identificar a assinatura dos sistemas produtivos de Sardinha e Ipanema. A presença de inclusões ricas em Ti foi uma característica típica dos artefatos coletados no sítio de Sardinha.

AbstractThe present investigation analysed iron artefacts collected in two sites around Araçoaiaba Hill. A known methodology was adapted to investigate several samples collected at the Royal Iron Factory of São João do Ipanema and Sardinha sites. EDX microanalysis results of non-metallic inclusions were plotted in bivariate graphs. Linear regression (with and without the zero-intercept constraint) and line intercept significance tests were applied to interpret these results. The analysis did not allow the identification of the provenance of the production systems of Sardinha and Ipanema sites. The presence of Ti-rich inclusions was an unambiguous attribute of the samples collected at the Sardinha site.