A new ferritic steel branded as Thor(TM) 115 has been developed to enhance high-temperature resistance. The steel design combines an improved oxidation resistance with long-term microstructural stability. The new alloy, cast to different product forms such as plates and tubes, was extensively tested to assess the high-temperature time dependent mechanical behavior (creep). The main strengthening mechanism is precipitation hardening by finely dispersed carbide and nitride phases. Information on the evolution of secondary phases and time-temperature-precipitation behavior of the alloy, essential to ensure long-term property stability, was obtained by scanning transmission electron microscopy with energy dispersive spectroscopy, and by X-ray Powder Diffraction on specimens aged up to 50,000 hours. A thermodynamic modeling supports presentation and evaluation of the experimental results. The evolution of precipitates in the new alloy confirms the retention of the strengthening by secondary phases, even after long-term exposure at high temperature. The deleterious conversion of nitrides into Z phase is shown to be in line with, or even slower than that of the comparable ASME grade 91 steel.

Microstructural Evolution of Thor(TM) 115 Creep-Strength Enhanced Ferritic Steel / Ortolani, Matteo; D'Incau, Mirco; Ciancio, Regina; Scardi, Paolo. - In: METALLURGICAL AND MATERIALS TRANSACTIONS. A, PHYSICAL METALLURGY AND MATERIALS SCIENCE. - ISSN 1073-5623. - ELETTRONICO. - 48:12(2017), pp. 6111-6117. [10.1007/s11661-017-4353-x]

Microstructural Evolution of Thor(TM) 115 Creep-Strength Enhanced Ferritic Steel

Ortolani, Matteo;D'incau, Mirco;Scardi, Paolo
2017-01-01

Abstract

A new ferritic steel branded as Thor(TM) 115 has been developed to enhance high-temperature resistance. The steel design combines an improved oxidation resistance with long-term microstructural stability. The new alloy, cast to different product forms such as plates and tubes, was extensively tested to assess the high-temperature time dependent mechanical behavior (creep). The main strengthening mechanism is precipitation hardening by finely dispersed carbide and nitride phases. Information on the evolution of secondary phases and time-temperature-precipitation behavior of the alloy, essential to ensure long-term property stability, was obtained by scanning transmission electron microscopy with energy dispersive spectroscopy, and by X-ray Powder Diffraction on specimens aged up to 50,000 hours. A thermodynamic modeling supports presentation and evaluation of the experimental results. The evolution of precipitates in the new alloy confirms the retention of the strengthening by secondary phases, even after long-term exposure at high temperature. The deleterious conversion of nitrides into Z phase is shown to be in line with, or even slower than that of the comparable ASME grade 91 steel.
2017
12
Ortolani, Matteo; D'Incau, Mirco; Ciancio, Regina; Scardi, Paolo
Microstructural Evolution of Thor(TM) 115 Creep-Strength Enhanced Ferritic Steel / Ortolani, Matteo; D'Incau, Mirco; Ciancio, Regina; Scardi, Paolo. - In: METALLURGICAL AND MATERIALS TRANSACTIONS. A, PHYSICAL METALLURGY AND MATERIALS SCIENCE. - ISSN 1073-5623. - ELETTRONICO. - 48:12(2017), pp. 6111-6117. [10.1007/s11661-017-4353-x]
File in questo prodotto:
File Dimensione Formato  
THORpaper2017.pdf

Solo gestori archivio

Descrizione: Articolo su rivista
Tipologia: Versione editoriale (Publisher’s layout)
Licenza: Tutti i diritti riservati (All rights reserved)
Dimensione 1.13 MB
Formato Adobe PDF
1.13 MB Adobe PDF   Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11572/188274
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 5
  • ???jsp.display-item.citation.isi??? 3
social impact