Efeito do molibdênio, boro e nióbio na transformação bainítica no resfriamento contínuo


In this work, the influence of molybdenum, boron and niobium alloy additions on the kinetics of bainite transformation of a traditional forging steel (AISI 5120) is studied, as part of an ongoing research aiming to obtain fully bainitic microstructures after forging and continuous cooling. CCT diagrams were obtained, using dilatometry, for four different alloys. Molybdenum delays the ferrite transformation, and associated with boron additions completely inhibited the ferrite transformation even for the lowest cooling rate used in this work (0,1°C/s). Niobium shows an effect on austenitic grain size before and after austenitization, but did not influence the austenite transformation kinetics. The specimens were characterized by metallography and hardness. The austenite fraction was measured by X-ray diffraction for all cooling rates and it was characterized a complex relation between cooling rate, austenite fraction and microstructure.

CARVALHO, Felipe Moreno Siqueira Borges de; BRAGA, Ana Paola Villalva; NISHIKAWA, Arthur Seiji; GOLDNSTEIN, Hélio. Efeito do molibdênio, boro e nióbio na transformação bainítica no resfriamento contínuo. In: CONGRESSO ANUAL DA ABM, 73., 2018, Sâo Paulo. Anais… São Paulo: ABM, 2018. p.1290-1301.

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