Influência do tratamento térmico no empenamento de latão durante o processo de usinagem por fresamento de topo

The brass alloys containing lead have been used in the machining process, and are used in manufacturing parts for use in “Hot Stamping” process. However, after machining processes, the pieces warp and are manually straightened with local load application directly on machined parts, generating scrap and losses of pieces because they warp to the opposite side. Heat treatments for stress relief reduce internal stresses in the alloys, been an alternative to the warping of this alloy. This work purpose an alternative treatment to that industrially used to eliminate the warping of the pieces. Therefore, it was studied brass alloys with and without lead, with and without heat treatment before and after machining. The heat treatment was stress relieving at 250° C. Measurements of warpage and dimensional variation, analysis of microstructure and chemical microanalysis were made. The warpage and dimensional change was observed only in samples machined not heat treated, this may have caused the increased grain size after the machining process. It was observed that the warpage can be related to the chemical composition of alloy added to the lamination process used to obtain the material to be machined and can be eliminated by thermal treatment.