Electromagnetic evaluation of the microstructure of Grade 91 tubes/pipes. (August 2015)

• Record Type: Journal Article
• Authors: Liu, Jun; Wilson, John; Strangwood, Martin; Davis, Claire L.; Peyton, Anthony; Parker, Jonathan
• Is Part Of: International journal of pressure vessels and piping. Volume 132(2015)
• Page Start: 65
• Page End: 71
• Publication Date: 2015-08
• Subjects: Grade 91 steel -- EM sensor -- Relative permeability -- BH loop -- Tube; Pressure vessels -- Periodicals; Pipe -- Periodicals; Récipients sous pression -- Périodiques; Tuyaux -- Périodiques; Pipe; Pressure vessels; Periodicals; 681.76041
• DOI: 10.1016/j.ijpvp.2015.05.009
• Languages: English
• ISSNs: 0308-0161

Abstract

Abstract: This paper assesses the feasibility of transferring a laboratory-based electromagnetic (EM) sensor technique, which has already proved sensitive to significant (e.g. phase balance) or subtle (e.g. number density of fine precipitates) microstructural changes in steel, to non-destructive evaluation of the microstructure of power generation components such as tubes/pipes. It has been found that Grade 91 steels, in different conditions representative of service entry, thermally aged or ex-service, can be distinguished using laboratory-based measurement systems on small machined cylindrical samples as well as by an industry deployment EM sensor system on full-diameter tube samples. The measurements for the tube samples follow the same trend as the machined cylindrical samples. The results indicate an industrial deployable sensor system can be used for sorting service-exposed or mis-heat-treated/mis-manufactured Grade 91 steel tubes/pipes from the correctly heat treated service-entry ones. Highlights: Industry deployable EM sensor system for characterizing microstructure in T91 tubes. Deployable sensor measurements follow same trend as the laboratory-based system. Mis-heat treated tube can be distinguished from 'correct' service-entry condition.