Abstract

In recent years, the role of thermal power plants has shifted from providing a baseload to providing supplemental supply to compensate for fluctuations in the output of renewable energy sources. Thus, the operation of these plants involves frequent startup and shutdown cycles, which lead to extensive damage caused by creep and fatigue interactions. In addition, the piping utilized in thermal plants is subjected to a combined stress state composed of bending and torsional moments. In this study, a high-temperature fatigue testing machine capable of generating such a bending-torsional loading was developed. Creep-fatigue tests were conducted on P91 steel piping with weldment. The results clarified that the creep-fatigue life was reduced by the superposition of the torsional and bending moments and that it was further reduced by a holding load. It was shown that the creep-fatigue life of piping with weldment can be estimated accurately using the equivalent bending moment, which is composed of the torsional and bending moments. It was also confirmed that crack occurred in the heat-affected zone (HAZ) of the welded part, which has been often observed in actual thermal power equipment. From the finite element analysis, it was identified that cracking was initiated in the HAZ due to the accumulation of creep strain and increase in the hydrostatic pressure component during a holding load.

References

1.
Yeo
,
W. H.
,
Fry
,
A. T.
,
Inayat-Hussain
,
J. I.
, and
Purbolaksono
,
J.
,
2021
, “
Remnant Creep Life Estimation Approach for Alloy 617 Tubes of Ultra-Supercritical Thermal Power Plants
,”
Eng. Failure Anal.
,
130
, p.
105746
.10.1016/j.engfailanal.2021.105746
2.
Ogata
,
T.
,
Sakai
,
T.
, and
Yaguchi
,
M.
,
2010
, “
Damage Evolution and Life Prediction of a P91 Longitudinal Welded Tube Under Internal Pressure Creep
,”
ASME J. Pressure Vessel Technol.
,
132
(
5
), p.
051204
.10.1115/1.4001688
3.
Viswanathan
,
R.
,
2000
, “
Life Management of High-Temperature Piping and Tubing in Fossil Power Plants
,”
ASME J. Pressure Vessel Technol.
,
122
(
3
), pp.
305
316
.10.1115/1.556187
4.
Abe
,
F.
,
2016
, “
Progress in Creep-Resistant Steels for High Efficiency Coal-Fired Power Plants
,”
ASME J. Pressure Vessel Technol.
,
138
(
4
), p.
040804
.10.1115/1.4032372
5.
Asayama
,
T.
,
Aoto
,
K.
, and
Wada
,
Y.
,
1993
, “
Effect of Nonproportional Loading on Creep-Fatigue Properties of 304 Stainless Steel at Low Strain Ranges Near the Elastic Region
,”
Nucl. Eng. Des.
,
139
(
3
), pp.
299
309
.10.1016/0029-5493(93)90172-6
6.
Inoue
,
T.
,
Kishi
,
S.
,
Koto
,
H.
, and
Takahashi
,
Y.
,
1994
, “
Fatigue-Creep Life Prediction of 21/4Cr-1Mo Steel Under Combined Tension-Torsion at 600 °C
,”
Nucl. Eng. Des.
,
150
(
1
), pp.
119
127
.10.1016/0029-5493(94)90056-6
7.
Shang
,
D. G.
,
Sun
,
Q. G.
,
Yan
,
C. L.
,
Chen
,
J. H.
, and
Cai
,
N.
,
2007
, “
Creep-Fatigue Life Prediction Under Fully-Reversed Multiaxial Loading at High Temperatures
,”
Int. J. Fatigue
,
29
(
4
), pp.
705
712
.10.1016/j.ijfatigue.2006.06.010
8.
Nakayama
,
Y.
,
Ogawa
,
F.
,
Hiyoshi
,
N.
,
Hashidate
,
R.
,
Wakai
,
T.
, and
Itoh
,
T.
,
2021
, “
Evaluation of Multiaxial Low Cycle Creep-Fatigue Life for Mod. 9Cr-1Mo Steel Under Non-Proportional Loading
,”
ISIJ Int.
,
61
(
8
), pp.
2299
2304
.10.2355/isijinternational.ISIJINT-2020-780
9.
Eggeler
,
G.
,
Ramteke
,
A.
,
Coleman
,
M.
,
Chew
,
B.
,
Peter
,
G.
,
Burblies
,
A.
,
Hald
,
J.
,
Jefferey
,
C.
,
Rantala
,
J.
,
deWitte
,
M.
, and
Mohrmann
,
R.
,
1994
, “
Analysis of Creep in a Welded ‘P91’ Pressure Vessel
,”
Int. J. Pressure Vessels Piping
,
60
(
3
), pp.
237
257
.10.1016/0308-0161(94)90125-2
10.
Li
,
M.
,
Barrett
,
R. A.
,
Scully
,
S.
,
Harrison
,
N. M.
,
Leen
,
S. B.
, and
O'Donoghue
,
P. E.
,
2016
, “
Cyclic Plasticity of Welded P91 Material for Simple and Complex Plant Connections
,”
Int. J. Fatigue
,
87
, pp.
391
404
.10.1016/j.ijfatigue.2016.02.005
11.
Ragab
,
R.
,
Parker
,
J.
,
Li
,
M.
,
Liu
,
T.
, and
Sun
,
W.
,
2021
, “
Modelling of a Grade 91 Power Plant Pressurized Header Weldment Under Ultra Super-Critical Creep Conditions
,”
Int. J. Pressure Vessels Piping
,
192
, p.
104389
.10.1016/j.ijpvp.2021.104389
12.
Kim
,
W. G.
,
Sah
,
I.
,
Kim
,
S. J.
,
Lee
,
H. Y.
, and
Kim
,
E. S.
,
2021
, “
Creep and Creep Crack Growth Behaviors for Base, Weld, and Heat Affected Zone in a Grade 91 Weldment
,”
Nucl. Eng. Technol.
,
53
(
2
), pp.
572
582
.10.1016/j.net.2020.07.015
13.
Takahashi
,
Y.
, and
Tabuchi
,
M.
,
2011
, “
Creep and Creep-Fatigue Behavior of High Chromium Steel Weldment
,”
Acta Metall. Sin.
,
24
(
3
), pp.
175
182
.10.11890/1006-7191-113-175
14.
Takahashi
,
Y.
,
Nishinoiri
,
S.
, and
Yaguchi
,
M.
,
2016
, “
Development of Analytical Evaluation Methods for Creep Failure in Weldments of High Chromium Steels and Application to Full Scale Pipe Experiments
,”
ASME
Paper No. PVP2016-63834.10.1115/PVP2016-63834
You do not currently have access to this content.