Browsing by Author "Armentia, Jorge"
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Item Ladle furnace slag characterization through hyperspectral reflectance regression model for secondary metallurgy process optimization(2017-11-13) Picon, Artzai; Vicente Rojo, Asier; Rodriguez-Vaamonde, Sergio; Armentia, Jorge; Arteche, Jose Antonio; Macaya, Inaki; Vicente, Asier; Tecnalia Research & Innovation; COMPUTER_VISION; INDUSTRY_THINGSIn steelmaking process, close control of slag evolution is as important as control of steel composition. However, there are no industrially consolidated techniques that allow in-situ analysis of the slag chemical composition, as in the case of steel with OES-spectrometers. In this work, a method to analyze spectral reflectance of ladle furnace slag samples to estimate their composition is proposed. This method does not require sample preprocessing and is based on a regression algorithm that mathematically maps the spectral reflectance of the slag with its actual composition with errors lower than 10%. Specifically designed normalization and calibration steps have been proposed to allow a global model training with data from different locations. This allows real-time monitoring of the thermodynamical state of the steel process by feeding a thermodynamic equilibrium optimization model. The system has been validated on several ArcelorMittal locations achieving process savings of 0.71 Euro per liquid steel tons.Item Material saving by a combination of rotary forging and conventional processes: Hybrid forging for net-shape gear: Hybrid forging for net-shape gear(American Institute of Physics Inc., 2019-07-02) Varela, Sonia; Valbuena, Oscar; Armentia, Jorge; Larrucea, Francisco; Manso, Virginia; Santos, Maite; Arrazola, Pedro; Saenz de Argandona, Eneko; Otegi, Nagore; Mendiguren, Joseba; Saez de Buruaga, Mikel; Madariaga, Aitor; Galdos, Lander; PROMETAL; INDUSTRY_THINGS; SGIncreasing efficiency in raw material and energy usage is vital, even more in sectors, such as the hot forging industry, where material accounts for 50% of component price and energy costs are continuously rising. One of the methods to achieve this is to minimize material waste. Traditionally, high-quality gears for the automotive sector are machined to shape from forged preforms which is wasteful of both materials and energy. Attention has now turned to the forging of tooth gears by conventional forging. However, this could require high forging loads and therefore huge press sizes. Some gears may also be difficult to form due to the placement of their teeth. Forging of tooth gears is thus not a straightforward task. In this context, rotary forging is a powerful alternative. It uses incremental deformation locally with the material to achieve near net shape results, minimizing machining. Due to the reduction in contact, it also allows the forging load to be decreased substantially, resulting in smaller presses. This paper shows the development of the rotary forging process in combination with conventional forging to obtain crown gear teeth as a demonstration case. First, the hot conventional forging is shown, based on obtaining the rotary preform by a closed die forging operation. Then rotary forging is defined as a semi-finished operation to achieve the forged teeth. The objective is to reduce the initial billet weight, checking that folds and filling defects do not appear. A thermomechanical chained model has been developed based on FEM and experimental tests carried out in a pre-industrial environment. The prototypes result in increased yield from raw material (around 15% saving compared to machining) and they can be manufactured with less than 50% of the load required by conventional forging processes. Quality and metallographic requirements are also fulfilled.