Banca de QUALIFICAÇÃO: SILVIO ERASMO DE OLIVEIRA JUNIOR

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : SILVIO ERASMO DE OLIVEIRA JUNIOR
DATE: 26/09/2023
TIME: 14:00
LOCAL: https://conferenciaweb.rnp.br/sala/renato-29
TITLE:

Analysis of Phase Transformation and Hardening of Stainless Steel 201 During Cold Forming by Drawing

PAGES: 80
BIG AREA: Engenharias
AREA: Engenharia de Materiais e Metalúrgica
SUBÁREA: Metalurgia de Transformação
SPECIALTY: Conformação Mecânica
SUMMARY:

The study focuses on the characterization of phase transformation of stainless steel 201 during the cold forming process by drawing. Austenitic stainless steels have properties such as good corrosion resistance, formability, and toughness, which make them suitable for various applications. The austenite in these steels is metastable at room temperature, prone to transform into martensite after deformation, developing high strength and good formability. The overall goal of the study is to characterize stainless steel 201 through the drawing process, observing the transformation of austenitic phase into martensite. Specific objectives include checking the hardness increase of the material after the cold forming process, evaluating the tensile strength, elongation, and ductility at each reduction, analyzing the phase transformation from austenite to martensite through X-ray diffraction (XRD), and assessing the direction of drawing and hardening by optical microscopy. The results show that the initially austenitic sample remained metastable, with characteristic peaks of the face-centered cubic (FCC) structure. When stainless steel 201 undergoes hardening in the cold forming process, the phase transformation from γ austenite (FCC) to ε martensite (HCP) occurs gradually according to each area reduction. The characterization by XRD reveals the evolution of texture in the austenite and ε-martensite phases. No significant changes were observed in the steel ε=30%, but with more deformation (50%), the martensite fraction increases according to the hardening. The deformation is evenly distributed between austenite and ε-martensite in the steel ε=65%. The phase modifications in the microstructure due to hardening can be observed as the area reduction increases. The phase transformation from γ austenite to ε martensite begins with 23% area reduction, due to the increase of the hardening level and internal stresses due to crystallographic flaws. With 44% area reduction, the ε martensite (hcp) phase transformation becomes more evident, and cracks in the central part of the sample are verified due to internal stresses. With a 61% reduction, the product is stabilized in ε martensite (hcp), and the crack becomes more evident due to excessive hardening. The next steps of the study involve eliminating the cracks formed in the cold forming process, using heat treatment of stainless steel 201 to reduce structural defects and observe its behavior

COMMITTEE MEMBERS:
Presidente - Interno ao Programa - 1671298 - RENATO ALTOBELLI ANTUNES
Membro Titular - Examinador(a) Interno ao Programa - 1893637 - ALEJANDRO ANDRES ZUNIGA PAEZ
Membro Titular - Examinador(a) Externo à Instituição - JORGE LUIZ CARDOSO - UFC
Membro Suplente - Examinador(a) Interno ao Programa - 1671292 - SYDNEY FERREIRA SANTOS
Membro Suplente - Examinador(a) Interno ao Programa - 1282172 - ROBERTO GOMES DE AGUIAR VEIGA