A soldagem de metais dissimilares tem diversas aplicações na indústria. Notadamente na indústria alimentícia e na indústria nuclear, este tipo de junta, comum entre aço carbono A36 e aço inoxidável austenístico ou entre aço inoxidável austenístico e cobre e suas ligas, é sempre motivo de análise e cuidados especiais tendo em vista a necessidade de manter a integridade dos equipamentos. Variações térmicas e dimensionais durante o uso de equipamentos que possuem juntas de materiais dissimilares são sempre preocupantes porque nem sempre se conhece o histórico da fabricação ou mesmo da execução de alguma recuperação, dificultando o gerenciamento do envelhecimento. O conhecimento antecipado destas variações por meio do conhecimento da vida a fadiga pode contribuir muito no projeto, na escolha do processo de fabricação, na escolha do consumível de soldagem e obviamente na conservação e integridade do equipamento. Apresentam-se neste trabalho os resultados obtidos para as tensões residuais nas soldas dissimilares e as curvas S-N-P que relacionam tensão com o número de ciclos e a probabilidade de falha, para 4 metais: cobre eletrolítico, aço inoxidável AISI 304, aço inoxidável AISI 316L e aço carbono A36 que foram posteriormente soldados entre si.

The welding of dissimilar metals has many applications in industry. In special, in the food industry and nuclear industry, this type of joint, common between A36 carbon steel and austenitic stainless steel or between austenitic stainless steel and copper and its alloys, is always subject to analysis and special care to maintain equipments integrity. Thermal and dimensional variations during use of equipment that have dissimilar welds are always troubling because not always it is known the history of the manufacture or recovery, making the management of aging difficult. Advance knowledge of these variations through the knowledge of the fatigue life can greatly contribute in design, choice of manufacturing process, choice of consumables and obviously in the preservation and integrity of the equipment. This paper presents results achieved for the residual stresses in dissimilar welds and SNP curves relating tension with the number of cycles and the failure probability for four metals: electrolytic copper, austenitic AISI 304 and AISI 316L stainless steels and A36 carbon steel which were subsequently welded together.

Oral forces applied to human teeth during biting and mastication are normally described in the literature only in terms of their axial components. The purpose of this study was to fully determine the spatial characteristics of the oral resultant force - its normal and tangential components - for a given individual. A load cell was especially manufactured to measure oral force and was temporarily implanted as a prosthetic device in the dental arch of a volunteer, replacing his missing upper first molar. The mastication and occlusion tests were carried out in such a way the cell should withstand the loads applied to the molar, and its state of strain was recorded by strain gauges attached to it. Based on the results of these tests and using balance equations, normal and tangential components of the resultant oral force were determined. For direct occlusion, without interposition any obstacle between cusps, a peak normal force of 135 N was recorded simultaneously to a tangential force of 44 N. For mastication of biscuits, a peak normal force of 133 N and a tangential force of 39 N were obtained.

In a PWR nuclear power plant, the reactor pressure vessel (RPV) contains the fuel assemblies and reactor vessels internals and keeps the coolant at high temperature and high pressure during normal operation. The RPV integrity must be assured all along its useful life to protect the general public against a significant radiation liberation damage. One of the critical issues relative to the VPR structural integrity refers to the pressurized thermal shock (PTS) accident evaluation. To better understand the effects of this kind of event, a PTS experiment has been planned using an RPV prototype. The RPV material fracture behavior characterization in the ductile-brittle transition region represents one of the most important aspects of the structural assessment process of RPV's under PTS. This work presents the results of fracture toughness tests carried out to characterize the RPV prototype material behavior. The test data includes Charpy energy curves, T0 reference temperatures for definition of master curves, and fracture surfaces observed in electronic microscope. The results are given for the vessel steel in the "as received" and normalized conditions. This way, the influence of the normalizing treatment on the fracture properties of the steel could be evaluated.