Caracterização microestrutural em função da temperatura de serviço de tubos de aços HP-Modificados ao Nb e Ti envelhecidos em fornos de reforma a vapor
type: CreativeWork
description: Hydrogen is produced in reforming furnaces inside tubes, which are currently manufactured with HP-Nb and HP-NbTi steels. The service temperature of these tubes causes different degrees of metallurgical aging along their lengths. The purpose of the present work is to characterize the aging of these steels at different temperatures, taking into account the effects ofNb and Ti additions, to establish an aging classification criterion for these alloys. For this, four deactivated reforming tubes were analyzed, presenting compositionswith low Nb or high Nb and with or without micro additions of Ti. It was verified that the aging stage classification criterion for HP steels can be based on the one used for HK steels, considering, however, three factors: NbC "Chinese script" morphology in stage I, except for those steels with Ti or Zr; secondary precipitation in the aging stages II and III as a function of Cr/Nb ratio; and a more uniform distribution of secondary precipitation for steels with high Nb in the absence of Ti in aging stage IV.
abstract: Hydrogen is produced in reforming furnaces inside tubes, which are currently manufactured with HP-Nb and HP-NbTi steels. The service temperature of these tubes causes different degrees of metallurgical aging along their lengths. The purpose of the present work is to characterize the aging of these steels at different temperatures, taking into account the effects ofNb and Ti additions, to establish an aging classification criterion for these alloys. For this, four deactivated reforming tubes were analyzed, presenting compositionswith low Nb or high Nb and with or without micro additions of Ti. It was verified that the aging stage classification criterion for HP steels can be based on the one used for HK steels, considering, however, three factors: NbC "Chinese script" morphology in stage I, except for those steels with Ti or Zr; secondary precipitation in the aging stages II and III as a function of Cr/Nb ratio; and a more uniform distribution of secondary precipitation for steels with high Nb in the absence of Ti in aging stage IV.
author: Queiroz, Fábio dos Santos.
language: por
keywords: Planejamento Energético, Aços HP, Tubo de forno de reforma
date published: 2017-06
date modified: 2026-07-24T01:16:29Z
provider: Brazil UERJ
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Universidade Federal do Rio de Janeiro

PropertyValue
property ID: Handle
value: http://hdl.handle.net/11422/8303