AN ANALYSIS OF A SET OF CREEP DATA FOR A 9CR-1MO-0.2V (P91 TYPE) STEEL

Recently published creep data for a 9Cr-1M-0.2V steel are analysed and an attempt is made to interpret them applying the concept of thermall y activated detachment of dislocations from carbide particles as the r ate controlling process. For the data, very high and stress dependent apparent activation energy of creep, Q(c), and very high and temperatu re dependent apparent stress exponent, m(c), are characteristic. The m odelling of creep behavior applying the above mentioned concept is sho wn to fail to account for this temperature and applied stress dependen ce of minimum creep strain rate and/or the values of Q(c) and m(c) fol lowing from the data analysis. It is suggested that the behavior of th e dislocation substructure, which is affected by the presence of carbi de particles, must be introduced into any model to adequately describe the unusual creep behavior of the steel of interest. (C) 1997 Elsevie r Science S.A.