Life Estimation of Cracked Stainless Steel Components Under Creep Conditions

1991 ◽  
Vol 113 (3) ◽  
pp. 303-306 ◽  
Author(s):  
V. M. Radhakrishnan ◽  
M. Kamaraj ◽  
V. V. Balasubramaniam
Keyword(s):  
Stainless Steel ◽  
Crack Growth ◽  
Nuclear Power ◽  
State Energy ◽  
Creep Crack Growth ◽  
Experimental Investigations ◽  
Plane Stress Condition ◽  
Line Integral ◽  
Energy Rate ◽  
Creep Crack

Experimental investigations have been carried out to study the creep crack growth in types 316, 308 Cb, and 304 L stainless steel in the temperature range of 873–1073 K under plane stress condition. Testings have been carried out with both the base metal and the welded composite joints, because such joints are commonly used in nuclear power industries. Among the various parameters tried to correlate the creep crack growth, the energy rate line integral has been found to give the best description of the crack growth rate. The steady-state energy rate line integral has been found to correlate well with the rupture time. Based on this observation, life estimations are presented for thin components containing various initial defect sizes.

An Analysis of High-Temperature Crack Growth in Type 308 Cb Stainless Steel and Its Weldment

1991 ◽  
Vol 113 (4) ◽  
pp. 538-541
Author(s):  
V. M. Radhakrishnan ◽  
M. Kamaraj
Keyword(s):  
Stainless Steel ◽  
Crack Growth ◽  
Creep Crack Growth ◽  
Crack Growth Behavior ◽  
Plane Stress Condition ◽  
Line Integral ◽  
Steady State Condition ◽  
Energy Rate ◽  
Creep Crack ◽  
Type C

Creep crack growth behavior of type 308 Cb austenitic stainless steel and its weldment has been studied in the temperature range of 875 to 1075 K under plane stress condition. The creep crack growth (CCG) rate has been correlated with parameters like stress intensity factor, K, net section stress and energy rate line integral C*. Among these parameters C* appears to describe well the CCG rate in both the cases of base metal and weldment. The rupture time tr of the cracked material has been found to be related to the energy rate line integral C*s in the steady-state condition, given by a relation of the type C*s · tr = constant.

Numerical Simulation of Creep Crack Propagation for Austenitic Stainless Steel 0Cr18Ni9 at 550°C

2011 ◽  
Vol 230-232 ◽  
pp. 596-599
Author(s):  
Li Jie Chen ◽  
Zun Qun Gong ◽  
Qi Zhao
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Crack Propagation ◽  
Crack Growth ◽  
Elevated Temperatures ◽  
Creep Crack Growth ◽  
Tensile Creep ◽  
Computational Error ◽  
Propagation Length ◽  
Creep Crack

First, tensile creep curve and creep propagation tests are conducted for austenitic stainless steel 0Cr18Ni9, i.e. 304 stainless steel at 550°C. The corresponding time hardening creep law is given for stresses ranging from 240 to 320 Mpa and the creep crack propagation length under a tension load of 10kN is measured by using QUESTAR long focus microscope system. Second, with the commercial finite element (FE) code ANSYS, the critical crack tip opening displacement (CTOD) is considered as crack propagation criterion to simulate the creep crack growth in the standard compact tension (CT) specimen. The FE predictions of the creep crack length in the primary and secondary stages are found to agree reasonably with the experimental results. The maximum computational error between the predictions and the experiment results is within 10%. Hence, the critical CTOD is a feasible criterion for crack growth simulations at elevated temperatures.

Experimental Investigation of Constraint Effects on Creep Crack Growth

2002 ◽  
Author(s):  
Adam D. Bettinson ◽  
Noel P. O’Dowd ◽  
Kamran M. Nikbin ◽  
George A. Webster
Keyword(s):  
Stainless Steel ◽  
Crack Growth ◽  
Creep Crack Growth ◽  
Compact Tension ◽  
Growth Data ◽  
Creep Crack ◽  
Low Constraint ◽  
Constraint Effects ◽  
Crack Growth Model ◽  
Crack Growth Rates

In this work the effects of specimen size and type on creep crack growth rates in stainless steel are examined. Experiments have been carried out on high constraint compact tension specimens (CT) and low constraint centre cracked panels (CCP) of ex-service 316H stainless steel. All testing was carried out at 550°C. Constraint effects have been observed in the data, with the large CT specimens having the fastest crack growth rate and the small CCP specimens the slowest. These trends are consistent with those that would be predicted from two parameter (C*–Q) theories. However, it is found that a constraint dependent creep crack growth model based on ductility exhaustion overpredicts the constraint dependence of the crack growth data.

Specimen Orientation and Constraint Effects on the Creep Crack Growth Behaviour of 316H Stainless Steel

2012 ◽  
Author(s):  
A. Mehmanparast ◽  
C. M. Davies ◽  
D. W. Dean ◽  
K. M. Nikbin
Keyword(s):  
Stainless Steel ◽  
Crack Growth ◽  
Creep Crack Growth ◽  
Compact Tension ◽  
Crack Growth Behaviour ◽  
Creep Crack ◽  
Uniaxial Creep ◽  
Microstructural Effects ◽  
Specimen Orientation ◽  
Constraint Effects

Pre-compression (PC) is found to have strong effects on the tensile, uniaxial creep rupture and creep crack growth (CCG) behaviour of type 316H stainless steel at 550 °C. In this work, blocks of 316H steel have been pre-compressed to 8% plastic strain at room temperature and compact tension, C(T), specimens are extracted from the pre-strained blocks with loading directions parallel and normal to the PC axis. The influence of specimen orientation and thickness on the CCG behaviour of the PC material is examined. The results are compared to short term and long term CCG behaviour of 316H steel at the same temperature. Higher CCG rates and shorter CCI times have been found in PC material with a loading direction normal to the PC axis compared to that parallel to the PC axis. These observations are discussed with respect to the microstructural effects.

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