Engenharia de Materiais
URI permanente desta comunidadehttps://repositorio.fei.edu.br/handle/FEI/17
Navegar
2 resultados
Resultados da Pesquisa
- Gelcasting of stainless steel powder: An alternative to injection molding(2010) Ortega F.S.; Oliveira R.L.S.; Plinio Jr. M.C.; Nobrega B.N.The gelcasting process is a forming technique originally developed for the shaping of advanced ceramics into final products in attempts to overcome some of the limitations of conventional forming techniques used in powder metallurgy. It is based on preparing a high solids loading suspension of powder dispersed in an aqueous organic monomers solution, which is poured into a mold and gelled through a chemically initiated polymerization. This work describes the gelcasting of HK-30 stainless steel, a type of powder commonly processed by injection molding. Large (70 x 30 mm) and geometrically complex green compacts with outstanding form retention and stability were obtained. Sintered parts showed good surface finishing and reached 96% of theoretical density, yield strength of 418.5 MPa, and ultimate strength of 701.5 MPa. These results compare favorably with those typically obtained through conventional powder injection molding of HK-30 feedstocks. They support the growing view that gelcasting may soon become an industrial, low cost alternative for near net shaping metallic powders into small or large parts with complex geometries © (2010) Trans Tech Publications.
- Effect of gel chemistry on the machinability of green SiC parts produced by gelcasting(2012) Riviello A.M.; Ortega F.S.The growing interesting in the use of silicon carbide in automotive components, biomaterials, energy, among others, which demand the production of parts with complex geometry that are difficult to obtain by conventional compaction techniques, motivates the search for developing new conformation processes. Within this context, this paper investigates the production of pieces of silicon carbide through the gelcasting process and subsequent green machining of these parts. Three systems of monomers were studied: MAM-NVP-MBAM, MAM-PEG (DMA) and MAM-HMAM. The effect of the concentration of monomers, concentration of chemical initiator and the ratio of chain-forming and crosslinker monomers on the cutting force during machining and surface roughness were evaluated. These data are compared with values of flexural strength and hardness of samples produced under the same conditions. Through a statistical analysis it was determined the best formulation for the production of parts of SiC with favorable characteristics of green machining. © (2012) Trans Tech Publications, Switzerland.