Análise da influência da região de retirada de corpos de prova no controle de qualidade do processo de injeção de cabeçotes

Abstract

In the present undergraduate thesis, the influences of the specimens obtaining region were analyzed, as well as their manufacturing processes, on their microstructure, and consequently on their mechanical properties. Therefore, the feasibility of using test specimens taken from regions originating in the process, and from new regions proposed for the tests, is studied in the quality control of the manufacturing process by low pressure die casting of Al-Si-Cu alloys for cylinder heads, thermally treated under T7 heat treatment, produced in Renault do Brasil's aluminum injection plant. It is then proposed to carry out these tests on specimens with cylindrical geometry, conducted under Renault-Nissan standards and under NBR ISO 6892-1, extracted from the deck face region of the HR16 engine head, a region considered critical for mechanical requests due to its application, replacing tests carried out on flat specimens taken from a different region. The heads selected for this test were sectioned in order to extract the original flat specimens, common to the quality control process implemented in the industry, and from the same pieces samples were taken from the regions proposed for the test with specimens of cylindrical geometry, which were manufactured using a CNC lathe. The results of mechanical tests conducted under traction show the differences between the mechanical properties of the different samples taken, caused by the different dendritic growth found in different regions, evidenced through the metallographic analysis present in this work. It is also noted the influence of the cooling rate in the different regions of the cast body, in accordance with Chvorinov's rule, and its influence on the microstructure found, as well as its influence on the mechanical properties.