ESTUDO DO TRATAMENTO TÉRMICO DE UM AÇO INOXIDÁVEL MARTENSÍTICO PARA MOLDES

• Autor(a) principal: Rodrigo Reis Marques Cabral
• Data de Publicação: 2021
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: https://hdl.handle.net/10216/137249
• topic: Engenharia dos materiais; Materials engineering

The aim of the present study is to determine the effect of austenitizing temperature and tempering temperature, as well as the cryogenic cooling in Tyrax ESR microstructure and its properties. There have been studied three austenitizing temperatures (at 1050, 1080 and 1100°C), two tempering temperatures (at 200 and 540°C) and cryogenic cooling process at -196°C. The mechanical properties were examined through impact and hardness test. The microstructure analysis was carried out by optic microscopy. The residual austenite was evaluated through X-rays diffraction, while corrosion resistance by the means of salt spray neutral fog test. The results showed that at quenched state, the hardened steel at 1100°C presented the highest hardness. These results are due as an effect of carbides dissolution and the respective increase of super-saturation of martensite. The steel tempering studied at 540°C have suffered embrittlement, which has produced a significant loss in toughness. A localized corrosion increase was observed concerning tempering at 540°C, as a result of higher precipitation of chromium carbides at the process of secondary hardening.