Efeitos da geometria, da força axial e da rotação no reparo por atrito

Abstract

Interventions made in the oil industry for repairs in structures and mechanical components, represents nowadays high financial costs. It is even worse since the operations are made in explosion risk areas. The electric arc welding is one of the most common techniques in this kind of repair. However, this technique has many inconveniences, some of them are: hyperbaric welding, need of drydock structure, welding bead porosity, material embrittlement due to hydrogen adsorption and brittle phases formation with low fracture toughness. By consist in a process carried out in the solid-phase, the scratch repair by friction shows many advantages. Lower temperatures are involved and the process is not affected by external environment, therefore the problems in submersed structure repairs are minimized. Consequently, the proceedings had the purpose of the optimization of the parameters of the scratch repair by friction process, presenting a special effort in the effects of the geometry, the axial-force and the rotation on the quality of the repair. The study was accomplished through metallographic investigations in the obtained repairs, and analysis by the survey of hardness profile and flexure tests on the repair section. Throughout systematic variations of these parameters, some geometries were selected, as well as forces, rotations and burn-off length, which led the acquirement of repairs free of imperfections. Amongst the investigated parameters, the highlighted was the great influence of the geometry of the whole and the consumable rod, in the obtention of optimized repairs.