Papers by Author: E.S. Jesus Filho

Abstract: Machining tools (interchangeable inserts) were manufactured from spray formed AISI M2 high-speed steel. The spray formed materials were mechanical and microstructural characterised. An assessment of the machining performance of the spray formed high-speed steel was attained. These results were compared to materials obtained by conventional and powder metallurgy techniques. The results showed that under the used process conditions (hot rolling and heat treating), the spray formed material showed a machining behaviour near closed to other materials; and highlight the potential of the spray forming technique for the obtention of materials with adequate properties for machining tools manufacturing.

Abstract: This work presents aspects related to new sintered materials for valve seat inserts application. Two types of materials were evaluated. The materials were made using powder metallurgy technique from a basic mixture of high-speed steel (AISI M3/2), iron and carbide powders. The microstructures of these materials before and after heat treatment are presented. Under the heat treatment condition, the activation of the diffusion mechanism among phases was promoted and a better distribution of the Cu phases along the matrix was achieved. The results indicate that the materials under development have a potential for commercial application as valve seat inserts.

Abstract: This article shows some fabrication aspects related to the obtention of sintered valve seat insert. This insert was made of a mixture of high-speed steel powders and iron powders plus NbC. This is a new development aiming the substitution of Co alloys currently used for valve seat inserts. The physical properties, mechanical properties and machining behaviour are discussed. The machining characteristics in terms of tool wear, cutting forces and chips morphology of the insert was compared to available commercial insert. The machining results indicate that the material under development has potential for commercial application and shows good machining evidences, in terms of equivalent cutting forces for ceramic tool. In addition, the machining using hard metal tool was susceptible to hardness variation observed for the material under development. Therefore, the machining tests point out the necessity for a microstructure homogenisation of the obtained material.