S19  Usinagem dos Materiais    Titulo: MACHINABILITY OF THE PLASTIC INJECTION MOLD STEELS   Resumo : MACHINABILITY OF A CALCIUM TREATED PLASTIC INJECTION MOLD STEEL WAS EVALUATED AND COMPARED TO A SIMILAR CONVENTIONAL PLASTIC INJECTION MOLD STEEL, DURING OF END MILLING (CANALS) WITH TIN COATED CEMENTED CARBIDE TOOLS. CALCIUM TREATMENT PROVIDES A MORPHOLOGY CONTROL OF THE HARD AND ABRASIVE ALUMINA AND SILICON INCLUSIONS PRESENT IN EVERY STEEL OWING TO CONVENTIONAL DEOXIDIZATION PROCESS WITH ALUMINUM OR SILICON, CALCIUM CHANGES THEM TO A SOFTER AND ROUNDED INCLUSIONS, BESIDES CONTROLLING THE COMPOSITION OF THE OXIDE INCLUSIONS, MAKING THEM TO STAY IN A VISCOUS STATE DUE TO HIGH TEMPERATURES REACHED AT THE CHIP-TOOL INTERFACE DURING MACHINING. THE TESTS SHOWED A TOOL LIFE INCREASING UP 76 % WHEN USING THE CALCIUM TREATED STEEL WHEN COMPARED TO THE CONVENTIONAL STEEL. KEY WORDS: MACHINABILITY, END MILLING, MOLD STEELS, CALCIUM TREATED MOLD STEELS, OXIDE INCLUSIONS.     Autores : Barbosa, Celso Antônio Machado, Álisson Rocha Milan, Júlio César Giubilei     Trabalho Completo :   COBEM99 | Comissão  Organizadora | Palestras | Sessões Técnicas | Autor | Simpósios e Sessões Especiais | Revisores |  Título  dos  Trabalhos | Local