3D temperature map reconstruction of a ceramic shell mold in investment casting process

This study analyzes the thermal behaviour of a ceramic shell mold during the a stage of the investment casting process. The investment casting process is a multi-step procedure which allows producing very reliable metal components such as turbine blades. Many parameters influence the final product of an investment casting process such as the initial mold temperature. This initial thermal status strongly affects the radiative heat transfer during the casting and, consequently, the product quality. This work describes and discusses the 3D temperature distribution over the ceramic shell mold of a turbine blade

INVESTMENT CASTING PROCESS: 3D TEMPERATURE MAP RECONSTRUCTION OF A CERAMIC SHELL MOLD

The purpose of this work is to experimentally reconstruct the 3D temperature map of a ceramic shell mold and to investigate its time-dependent thermal behavior during the final part of the investment casting process. The investment casting process is the most used technique to produce very reliable components. Nowadays, there are still too much failing processes that are unacceptable in terms of both plant downtime and material waste. These failing processes are mainly caused by a non-uniform cooling that can promote thermal gradients in the components leading to a generation of residual thermal stresses. The experimental 3D temperature map reconstruction and its time-dependent behavior are analyzed through the Infrared Thermography technique. Such a reconstruction allows to observe the presence of strong temperature gradients and quantify them. In the present case, the central part of the investigated ceramic shell mold shows strong temperature gradient. This central part is of extreme importance because of the presence of the blades housings. The temperature difference present on the blades housings increases with time leading to stronger temperature gradient

Introduzione

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Mammuthus meridionalis di Madonna della Strada (Scoppito, L'Aquila): Diagnostica e restauro.

The skeleton of Mammuthus meridionalis (Nesti, 1825), found in 1954 at Madonna della Strada (Scoppito, L\u2019Aquila, central Italy) and exhibited since 1960 in the Spanish Fortress in L\u2019Aquila, has recently undergone a complex diagnostic and restoration project funded by the \u201cGuardia di Finanza\u201d as a contribution to the reconstruction of the city of L\u2019Aquila after the earthquake of 6 April 2009. The specimen was only slightly damaged by the seismic event. The restoration based on a highly integrated multidisciplinary approach, began with a preliminary diagnostic analysis in order to acquire information on the state of preservation of the skeleton and on the dynamic behaviour of the metal supporting frame-skeleton assembly. The restoration was carried out by combining the most common techniques applied in Palaeontology with the most advanced techniques used for the restoration of cultural artefacts. The painstaking restoration enabled the original shape of the skeleton to be restored, revealing the actual shape of the skull and its pathological modifications. Before reassembling the skeleton, a new, correct posture was also defined