@Article{icces.2022.08750,
AUTHOR = {Jundong Yin, Lei Wang, Baoyin Zhu, Guodong Zhang, Dongfeng Li},
TITLE = {The Effect of Tempering Duration on the Creep Behavior of the P91  Steels at 600℃},
JOURNAL = {The International Conference on Computational \& Experimental Engineering and Sciences},
VOLUME = {24},
YEAR = {2022},
NUMBER = {1},
PAGES = {1--3},
URL = {http://www.techscience.com/icces/v24n1/48977},
ISSN = {1933-2815},
ABSTRACT = {High performance martensitic heat resistant steels are widely used in fossil fuel power plant 
industry due to because of their good creep resistance at high temperatures. In-depth 
understanding of the high temperature inelastic deformation mechanism of such steels is crucial 
to ensure the reliable, safe and efficient operation of the power plant [1]. The martensitic steels 
have a complex microstructure with a hierarchical arrangement, including a collection of packets 
in the prior austenite grain, blocks in the packet and laths along with dispersed nanoscale 
strengthening phases (e.g., MX precipitates and carbides). The purpose of this paper is to study the 
creep mechanisms with regard to the microstructure of the P91 martensitic steel at high 
temperature by means of experimental characterisation and finite element simulation. <br/>
In the present paper, the effect of tempering duration on the creep response of the P91 steel at 600
oC was experimentally examined with the precipitate size identified. Apart from the standard heat 
treatment (holding at 1060℃ for 40 min and then at 760℃ for 2 h) for the as-received P91 steels, 
secondary tempering treatment has been applied with different tempering time periods, e.g., 0 h 
(T0), 10 h (T10) and 20 h (T20) at 780℃. In order to simulate the creep response, crystal plasticity 
based micromechanical finite element model was developed based on the measured
microstructure [2]. The crystallographic slip at the block level is accounted for using an exponential
type of constitutive flow rule and the precipitate size effect is represented in the crystal plasticity 
model through the use of an internal variable in association with the slip resistance. The results 
show that the secondary tempering duration can significantly affect the creep behavior of the 
martensitic steel (see Fig. 1). It is found that with increasing tempering time period the precipitate 
size increases, which could lead to detrimental effect on material’s creep resistance. Similar effect 
of the precipitate size on the creep response has also been shown in literatures [3]. The measured 
creep response of the P91 steels with different heat treatments at different stress levels can be 
predicted by the developed micromechanical model. The micromechanical modelling results show 
(see Fig. 2) that the accumulated equivalent plastic strain during the creep is strongly 
heterogeneous and the levels of the strain localization depend on the tempering duration.},
DOI = {10.32604/icces.2022.08750}
}