Foundry

A fundição artística no Rio de Janeiro durante o Segundo Reinado aparece como um tema escassamente estudado pela historiografia e tradicionalmente entendido como um fenômeno quase inexistente, situado na tênue fronteira entre as “belas artes” e as “artes industriais” ou aplicadas”. Por meio deste artigo, mostramos com dados na sua maioria inéditos, como, apesar de não ser uma indústria consolidada nem muito produtiva, a fundição artística foi um fenô- meno recorrente ao longo do século xix no Rio de Janeiro, com fundidores e obras relevantes que se inserem em um desejo de progresso e civilização dentro de uma reclamação pelo nacional diante da falta de encomendas, da falta de incentivos e de apoios.

Linear-elastic plane-strain fracture toughness of metallic materials is a method which covers the determination of the strain fracture toughness (KIC) of metallic materials by increasing-force test of fatigue precracked specimens. This method has been applied for investigating the fracture behaviour of cast iron. Two groups of cast alloys, Compacted Graphite Iron (CGI) and Spheroidal Graphite Iron (SGI) have been investigated. While SGI benefits of a wide scientific literature, CGI is a relatively unknown material despite of its large potentialities in industrial applications.

Spheroidal Graphite cast Iron (SGI), also known as ductile iron, represents a perfect material for a very large range of modern applications. It is successfully used wherever optimal strength, stiffness and even low costs are required: high values of tensile strength and Young's modulus are between its most appreciable propеrties. At the same time, nowadays, a different cast iron, known as Compacted Graphite Iron (CGI) or vermicular graphite iron, is taking the first steps in replacing SGI respect to some specific applications. It depends on a better castability, machinability and thermal resistance. CGI is an ideal cast iron in the case of components under simultaneous mechanical and thermal loadings, such as cylinder blocks and heads. Unfortunately, while SGI benefits of a wide scientific literature, CGI is a relatively unknown material. Moreover, dut to its particular microstructure, the production of CGI presents additional difficulties and it is not easy to obtain stable properties in the CGI alloy. This paper illustrates a way for the experimental evaluation of the Poisson's ratio by tensile specimens, comparing this propriety in the case of SGI and CGI.

The article investigates the possibility of using (combining) a frozen sand-water model, which is a source of steam when heated, and steam-microwave curing to obtain complex configurations of volume-closed forms, as well as the influence of mass
water content in the sand-water model on the surface quality of the obtained three-dimensional closed molds.
The studies used quartz sand brand 1K2O202, distilled water, sodium liquid glass with a silicate modulus of 2.8–3.0 and a specific gravity of 1.43–1.46 g/cm3, clad quartz sand 1 % liquid glass (by weight, more than 100 % sand) dried in air and in the field of
microwave radiation. The temperature was measured with a precise thermometer Greisinger G 1700 with an accuracy of 1 °C,ISSN 2077-1304. Met. lit'e Ukr., vol. 29, 2021. №1 (324) 45
ПРОЦЕСИ, ТЕХНОЛОГІЇ ТА МАТЕРІАЛИ ЛИВАРНОГО ВИРОБНИЦТВА
weighing was performed on electronic scales brand MH200 with an accuracy of 0.01 g. Form structuring, drying of clad sand,
heating of weighed portions of water, a mixture of water and sand, frozen portions of a mixture of water and sand were carried
out in a microwave oven with a nominal magnetron power of 900 W and a radiation frequency of 2.45 GHz.
The analysis of the obtained results shows that the combination of steam-microwave curing and the model of frozen sandwater mixture allows to obtain complex configurations of volume-closed forms. Manufactured molds according to this technical solution immediately after manufacture are suitable for use because they contain virtually no moisture and, accordingly,
virtually no gas. The proposed method can produce molds of any complexity, and their limitations in weight and size will be due
solely to the size of the working space of the used freezer and microwave.
It is established that the duration of water evaporation in the field of microwave radiation increases with increasing mass of
water that evaporates, and largely depends on the material of the medium from which it evaporates and its initial temperature.
For the manufacture of volume-closed forms, frozen models should be made from a mixture of quartz sand and 5–10 % of
water (by weight, over 100 % sand). The proposed method of manufacturing three-dimensional closed molds is quite technological and can be recommended for the production of small castings from alloys based on iron, copper, aluminum for general
engineering purposes in terms of single and small-scale production of castings.

Se desarrolló el colado de piezas de acero para herramientas D2, conocido en la Argentina como SPecial K. Se trata de un acero ledeburítico, con solidificación similar a la de una fundición blanca, con alto carbono, cromo, vanadio y molibdeno. Una vez obtenidas las piezas en bruto, fueron sometidas a tratamiento térmico de temple y revenido, para obtener la dureza necesaria