Mechanical resistance of welded joints in steels subjected to high temperature service

Abstract

The components of industrial plants that work at high temperatures (chemical / petrochemical plants and power generators) fail due to prolonged exposure to high temperatures and pressure, a phenomenon known as slow creep (creep).
The objective of this thesis is to study in a theoretical and experimental way welded joints made in ferritic - martensitic steels with 9% Cr, type P9 or P91 . Subsequently with nickel-based alloys, Inconel 601 (60 Ni - 25 Cr and Incolloy 800 H (30 Ni - 20 Cr) in all cases have high thermo-mechanical resistance associated with their microstructure.
Analyzing the behavior of steels subjected to a thermal cycle of arc welding carried out by two successive processes FCAW- * Arc Cored Wire * -, SMAW- * Protected Metal Arc * - and GTAW * -Gas-protected Tungsten Electrode- *, carrying out a systematic study that allows finding interrelations between the chemical composition of the material, the welding procedure, the microstructure and the properties of the welded joint, as well as the effects of the postweld heat treatment (PWHT) on the microstructure and properties. mechanical (traction, toughness and creep resistance)