Estudo da viabilidade de tixoforjamento da liga A2011 em matrizes não metalicas

AUTOR(ES)
DATA DE PUBLICAÇÃO

2002

RESUMO

The work presents an analysis of the viability of using refractory materials and low cost techniques, like phenol resin bound sand and cement bound sand, besides different refractory coatings, in the construction of tools (dies and punches) for forging the A2011 a11oy in the semisolid state (thixoforging). Die geometry was chosen to impose particularly difficult filling, on order to test the semi-solid slurry ability to flow. Semi-solid raw material was produced by a simple and practical method, however resulting in slurries with appropriate rheological properties, by partial melting of ultra-refined as-cast structures. Such structures were obtained by association of grain refiner addition and thermal effects during solidification. Thixoforging tests using non-metallic tools were performed in different process conditions, searching for viable parameters to obtain acceptable product quality. Results show the possibility of using the above mentioned materials for tools construction for forming in the semi-solid state. Results on analysis of the process parameters for thixoforging A2011 a11oy show that best products are obtained when temperatures in the die ranges from 330 to 380°C and applied forces are in the order of 130kN, for the specific chosen geometry. These values, both related to die temperatures and required forces are significantly lower than the required die temperature and applied forces when using steel to11s, for the same product (respectively 630°C and 270kN). Microstructures of thixoforged products present equiaxial A1-alpha phase throughout the product volume, with globule size ranging from 55 to 160mm. Liquid segregation towards the flowing front was observed during fi11ing of the die, leading to increase in hardness in the edges of the product

ASSUNTO(S)

conformação de aluminio ferramentas forjamento aluminio matrizes (trabalhos em metal)

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