Microstructure and Mechanical Properties of ASTM A743 CA6NM Steel Welded by FCAW Process

Autor(es)

Silva, Rafael de Paula ; Sodero Toledo Faria, Maria Ismenia ; Cursino Briet de Almeida, Luiz Fernando ; Nunes, Carlos Angelo ; Vieira, Decio ; Borges Junior, Wanderlei

• Tipo de documento: Artigo Científico
• Fonte: MATERIALS RESEARCH-IBERO-AMERICAN JOURNAL OF MATERIALS; v. 20, n. 6, p. 8-pg., 2017-11-01.

Resumo

CA6NM steel is widely used in the manufacture of hydraulic turbines metallic parts, due to its resistance to corrosion and cavitation damage, combined with good weldability and fatigue properties. However, welding of this type of steel is complex and to ensure a minimum residual stress after welding it is necessary perform a post welding heat treatment (PWHT) of the part. This study aims to analyze the effect of a PWHT on the microstructure and mechanical properties of CA6NM steel weld joint produced by the FCAW process and compare it with the characteristics of an as-welded joint. A martensitic microstructure has been present in both materials. However, the PWHT material has shown finely dispersed retained austenite, in an amount near 10 vol.%. Vickers microhardness values of all regions of PWHT welded joint present lower hardness values compared to those of the as-welded joint. Despite nearly identical toughness values of the weld metal from AW and PWHT samples, results of fracture analysis have shown distinct features in appearance of the fractures. (AU)

• Processo FAPESP: 14/19712-3 - Soldagem do aço inoxidável martensítico CA6NM pelo processo FCAW: simulação física da ZTA, tratamentos para alívio de tensão residual, caracterização microestrutural e mecânica
• Beneficiário: Maria Ismênia Sodero Toledo Faria
• Modalidade de apoio: Auxílio à Pesquisa - Regular