Effect of thermal aging on the microstructure and mechanical properties of stainless steel UNS S31803

Materia

article

Junia Maria Gândara Costa¹  José Carlos de Lacerda²  Leonardo Barbosa Godefroid¹  Luiz Cláudio Cândido¹ 

[1] Universidade Federal de Ouro Preto;Universidade Federal de Itajubá

关键词: Duplex stainless steel;    Embrittlement;    Sigma phase;    Mechanical properties;   

DOI  :  10.1590/S1517-707620220001.1328

学科分类：工程和技术（综合）

来源: Universidade Federal do Rio de Janeiro * Coordenacao dos Programas de Pos-Graduacao de Engenharia

【 摘 要 】

Duplex stainless steel UNS S31803 exhibits high mechanical strength with high corrosion properties, due to its microstructure composed of ferrite and austenite phases, in equal proportion. When the UNS S31803 steel is submitted to high temperatures, some precipitations can occur, such as nitrites, carbides, and third phases (e.g. sigma phase -σ, and alpha prime - α'). These phases are deleterious in relation to the mechanical properties and corrosion resistance, and their effects are analyzed regarding the properties of the steel. In order to evaluate the precipitation of this deleterious phase, isothermal treatment was done at 500°C for 144 hours (α' phase) and at 850ºC for 80 minutes (σ phase). The results were obtained through the microstructural analysis and tensile tests. The presence of sigma phase was verified in the grain boundary, an increase in the mechanical resistance with a loss of toughness. There was as well as an increase in mechanical resistance with the precipitation of α', with less loss of ductility than that observed in the experiments involving the presence of sigma phase.

【 授权许可】

CC BY