Effect of volume fraction of phases and precipitates on the mechanical behavior of UNS S31803 duplex stainless steel.

• Autor(a) principal: Lacerda, José Carlos de
• Data de Publicação: 2015
• Outros Autores: Cândido, Luiz Cláudio, Godefroid, Leonardo Barbosa
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UFOP
• Texto Completo: http://www.repositorio.ufop.br/handle/123456789/5347; https://doi.org/10.1016/j.ijfatigue.2014.12.015
• topic: Duplex stainless steel; Microstructure; Tensile and fatigue tests

Mechanical properties of a grade UNS S31803 duplex stainless steel were studied. Samples were annealed at three different temperatures, 1060 C, 1200 C, and 1300 C, to change the a/c proportion, to precipitate undesirable phases (for example, a0 , r and chromium nitrides), and to study the effect of the microstructure on the mechanical behavior. Specimens with a thickness of 1.8 mm were prepared according to ASTM standards and tested at room temperature. Tensile tests were conducted using displacement control at a rate of 5 mm/min. Force-controlled constant amplitude axial fatigue tests were conducted at a frequency of 30 Hz and an R stress ratio of 0.1. Microstructural analyses, performed by optical microscopy and scanning electron microscopy, showed the following modifications to the microstructure: changes in the phase volume fractions, the phase grain growths, and the morphology of the c-phase and the precipitation of chromium nitrides in the a-phase. The mechanical properties of the steel were significantly changed due to the changed microstructure. The results demonstrate the sensitivity of the steel to the annealing temperature.