en Research Paper Research Paper <div><span style="font-size:11pt"><span style="line-height:200%"><span new="" roman="" style="font-family:" times=""><span lang="EN-US" style="line-height:200%">High thermal conductivity, low coefficient of thermal expansion makes P92 a candidate material for Ultra Super Critical (USC) power plant piping. Microstructural features viz., high dislocation density, lath martensitic microstructure, fine precipitates of M₂₃C₆ and MX (X=C, N) contribute towards the high rupture strength. However, most components are typically subjected to multiaxial stress conditions; either metallurgical (weldments), or mechanical (change in the dimension). The present work involves stress rupture testing of circumferential 60&deg; V- notch specimens in the range of 300 &ndash; 375 MPa at 650 &deg;C. Notch strengthening effect was observed; with rupture times ranging from 200 &ndash; 1300 h. Scanning electron microscopy (SEM) fractography revealed mixed mode of fracture with brittle fracture observed at notch root, while ductile fracture was seen at the centre of the specimen. </span></span></span></span><br> &nbsp;</div> Multiaxiality,notched specimen,stress rupture,transient creep 70 76 http://ijmse.iust.ac.ir/browse.php?a_code=A-10-5162-1&slc_lang=en&sid=1 lakshmiprasad maddi prasadmlp@gmail.com 1800319475328460020118 1800319475328460020118 Yes Department of Basic Sciences and Humanities, GMRIT, Rajam, Andhra Pradesh, INDIA, 532127 Srinivas R Gavinola gavinolasrinivasreddy@gmail.com 1800319475328460020119 1800319475328460020119 No Department of Physics, Presidency University, Yelahanka, Bengaluru, Karnataka, INDIA, 560064. Atul Ballal ballal.atul@gmail.com 1800319475328460020120 1800319475328460020120 No Department of Metallurgical and Materials Engineering, Visvesvaraya National Institute of Technology, Nagpur, Maharashtra, INDIA, 440010.