Banca de QUALIFICAÇÃO: EDUARDO RODRIGUES DA SILVA

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
DISCENTE : EDUARDO RODRIGUES DA SILVA
DATA : 09/08/2017
HORA: 09:00
LOCAL: Sala de aulas do PPGCEM
TÍTULO:

Effect of the heat input on the microstructure of bead on plates of 3 variants of X65 API steels deposited by E81T1-Ni1C tubular wire

PALAVRAS-CHAVES:

API X65 steels, FCAW, microstructure, hardness, heat affected zone, fusion zone.

PÁGINAS: 90
GRANDE ÁREA: Engenharias
ÁREA: Engenharia de Materiais e Metalúrgica
RESUMO:

The objective of the present work is the microstructural characterization of weld beads deposited with E81T1-Ni1C tubular wire on 3 variants of X65 API steels. These are alternative materials used in the assembly of pipelines for the transportation of oil and gas, where the qualification of the welding procedures is a prerequisite for guaranteeing the mechanical properties of the component in service. In this context, the detailed characterization of the microconstituents that make up the three sub-regions of the weld is an essential tool, since it contributes with important elements for the understanding of the correlation between process variables and the final properties of the fabricated assembly. For this research, FCAW deposition of bead-on-weld beads under controlled welding conditions was performed, which allowed thermal input of 7.3, 11.3 and 22.1 KJ / cm. The microstructural characterization was done by optical microscopy and scanning electron microscopy with Field Emission Gun (FEG), where the high contrast quality in the images allows the identification and more detailed classification of the microconstituents present. The preliminary results show that the fusion zone (FZ) of the three alloys is predominantly formed by the microconstituint acicular ferrite (AF), with an average hardness of about 240 HV0,3, aspects that according to literature are requirements of excellent toughness. The coarse grained heat affected zone (HAZ-CG) showed for the 3 steels a microstructure basically formed by second phase ferrite (FS) and small fraction of primary ferrite. According to the microhardness profile along the sub-regions of the weld, the maximum peaks located in the HAZ-CG are less than 330 HV for the bead deposited with medium heat input, which is indicative of absence of martensite and good toughness for this critical region of the HAZ.

MEMBROS DA BANCA:
Presidente - 2156996 - AUGUSTO JOSE DE ALMEIDA BUSCHINELLI
Externo ao Programa - 1652765 - MAURÍCIO MHIRDAUI PERES
Externo ao Programa - 1938946 - NICOLAU APOENA CASTRO