Round robin on creep fatigue crack growth testing for verification of ASTM standard 2760-10

Saxena, Ashok; Narasimhachary, Santosh B.

doi:10.1179/0960340914z.00000000049

Cited by 9 publications

(10 citation statements)

References 4 publications

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“…The temperature compensated CCG rates are shown in shown in Figure 5 for the base metal regions of the Grade 91 steel. At the temperatures of 538 • C, 594 • C, 600 • C, and 650 • C, the CCG tests were conducted using new plate material while the tests conducted at 625 • C were performed on a material taken from an ex-service pipe; however, the pipe section used for testing was heat treated prior to testing to rejuvenate its microstructure to the original state [25][26][27]. The latter should, therefore, also be considered a new material.…”

Section: Ccg Behavior Of Grade 91 Materialsmentioning

confidence: 99%

“…Table 4a lists the chemical composition of the heat of the Grade 91 steel that experienced early cracking during the service used by Shingledecker [21] in his CCG studies in the service's exposed but rejuvenated condition. Thus, after the removal from the service, the material was heat treated to rejuvenate its microstructure to the original form prior to machining the CCG samples that were tested at 625 • C [21,[25][26][27]. Table 4b lists the actual levels of the trace elements S, Cu, Sn, As, Sb, and Pb along with levels that were seen to result in the creep damage resistant and creep damage prone behaviors in the Parker and Seifert [28] study; in other words, creep-ductile or creep-brittle behavior, respectively.…”

Section: Ccg Behavior Of Grade 91 Materialsmentioning

confidence: 99%

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A Phenomenological Model for Creep and Creep-Fatigue Crack Growth Rate Behavior in Ferritic Steels

Saxena

2023

Metals

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A model to rationalize the effects of test temperature and microstructural variables on the creep crack growth (CCG) and creep-fatigue crack growth (CFCG) rates in ferritic steels is described. The model predicts that as the average spacing between grain boundary particles that initiate creep cavities decrease, the CCG and CFCG rates increase. Further, the CCG data at several temperatures collapse into a single trend when a temperature compensated CCG rate derived from the model is used. The CCG and CFCG behavior measured at different temperatures is used to assess the effects of variables such as the differences between the base metal (BM), weld metal (WM), and heat-affected zone (HAZ) regions. The model is demonstrated for Grade 22 and Grade 91 steels using data from literature. It is shown that differences between the CCG behavior of the Grade 22 steel in new and ex-service conditions are negligible in the BM and WM regions but not in the HAZ region. The CCG behavior of the Grade 91 steels can be separated into creep-ductile and creep-brittle regions. The creep-brittle tendency is linked to the presence of excess trace element concentrations in the material chemistry. Significant differences found in the CCG rates between the BM, WM, and HAZ regions of the Grade 91 steel are explained.

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Section: Ccg Behavior Of Grade 91 Materialsmentioning

confidence: 99%

Section: Ccg Behavior Of Grade 91 Materialsmentioning

confidence: 99%

A Phenomenological Model for Creep and Creep-Fatigue Crack Growth Rate Behavior in Ferritic Steels

Saxena

2023

Metals

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“…Figures and , respectively, show the average time rate of crack growth, ( da / dt ) avg , during hold time as a function of ( C t ) avg from data provided by various laboratories in support of a recently concluded round‐robin study for tests conducted at 60‐ and 600‐second hold time on a P91 material . Table shows the various creep and mechanical properties of P91 material that was used in this round‐robin study . The ( da / dt ) avg was calculated by the dominant damage hypothesis described in Equation .…”

Section: Correlations Between Creep‐fatigue Crack Growth Rates and (C...mentioning

confidence: 99%

“…9 Table 1 shows the various creep and mechanical properties of P91 material that was used in this round-robin study. 9 The (da/dt) avg was calculated by the dominant damage hypothesis described in Equation (13). (C t ) avg was calculated using both Equation (4) referred to as measured values and Equation ( 6) referred to as calculated values.…”

Section: Introductionmentioning

confidence: 99%

Accounting for crack tip cyclic plasticity and creep reversal in estimating (C_t)_avg during creep‐fatigue crack growth

Saxena

Narasimhachary

2019

Fatigue Fract Eng Mat Struct

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Creep‐fatigue crack growth (C‐FCG) rates in a P91 steel at 625°C were correlated as the average time rate of crack growth during hold time, (da/dt)avg, with (Ct)avg. At 60‐second hold time, the rates were lower than for 600‐second hold time. At 600‐second hold time, the crack growth rates converged on to the creep crack growth rate (CCGR) trend. Thus, the CCGR trend represents the upper bound for time‐dependent crack growth rates in P91 materials. The analytical expressions based on considering just the elastic and secondary creep deformation rates overestimated the magnitudes of (Ct)avg by as much as a factor of 10 for the 600‐second hold time tests. After accounting for the effects of cyclic plasticity during unloading, and accounting for only partial reversal of creep strains accumulated during hold time, the estimates of (Ct)avg compared well with the measured values. CR represents the extent of crack tip creep strain reversal, and tpl is the time required for the crack tip creep zone during the hold time to become equivalent in size to the cyclic plastic zone in terms of stress carried by that region. Together, these parameters accurately account for the effects of crack tip cyclic plasticity on the magnitude of (Ct)avg. Both tpl and CR depend on material properties, and the latter also depends on the hold time. A parameter ϕ is introduced that is dependent only on material properties and from which CR can be estimated for a given hold time. tpl and ϕ can be reported as part of the test results from C‐FCG testing.

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“…Numerous researchers [4,5] have examined the X10CrMoVNb9-1 P91 steel's hightemperature crack development characteristics under constant load. Saad et al investigated P91 materials to develop a constitutive viscoplasticity model capable of reproducing the mechanical behavior of power plant materials under thermomechanical fatigue conditions [6].…”

Section: Introductionmentioning

confidence: 99%

Assessing Fatigue Life Cycles of Material X10CrMoVNb9-1 through a Combination of Experimental and Finite Element Analysis

Rahim,

Schmauder,

Manurung

et al. 2023

Metals

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This paper uses a two-scale material modeling approach to investigate fatigue crack initiation and propagation of the material X10CrMoVNb9-1 (P91) under cyclic loading at room temperature. The Voronoi tessellation method was implemented to generate an artificial microstructure model at the microstructure level, and then, the finite element (FE) method was applied to identify different stress distributions. The stress distributions for multiple artificial microstructures was analyzed by using the physically based Tanaka–Mura model to estimate the number of cycles for crack initiation. Considering the prediction of macro-scale and long-term crack formation, the Paris law was utilized in this research. Experimental work on fatigue life with this material was performed, and good agreement was found with the results obtained in FE modeling. The number of cycles for fatigue crack propagation attains up to a maximum of 40% of the final fatigue lifetime with a typical value of 15% in many cases. This physically based two-scale technique significantly advances fatigue research, particularly in power plants, and paves the way for rapid and low-cost virtual material analysis and fatigue resistance analysis in the context of environmental fatigue applications.

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Round robin on creep fatigue crack growth testing for verification of ASTM standard 2760-10

Cited by 9 publications

References 4 publications

A Phenomenological Model for Creep and Creep-Fatigue Crack Growth Rate Behavior in Ferritic Steels

A Phenomenological Model for Creep and Creep-Fatigue Crack Growth Rate Behavior in Ferritic Steels

Accounting for crack tip cyclic plasticity and creep reversal in estimating (C_t)_avg during creep‐fatigue crack growth

Assessing Fatigue Life Cycles of Material X10CrMoVNb9-1 through a Combination of Experimental and Finite Element Analysis

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Round robin on creep fatigue crack growth testing for verification of ASTM standard 2760-10

Cited by 9 publications

References 4 publications

A Phenomenological Model for Creep and Creep-Fatigue Crack Growth Rate Behavior in Ferritic Steels

A Phenomenological Model for Creep and Creep-Fatigue Crack Growth Rate Behavior in Ferritic Steels

Accounting for crack tip cyclic plasticity and creep reversal in estimating (Ct)avg during creep‐fatigue crack growth

Assessing Fatigue Life Cycles of Material X10CrMoVNb9-1 through a Combination of Experimental and Finite Element Analysis

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Accounting for crack tip cyclic plasticity and creep reversal in estimating (C_t)_avg during creep‐fatigue crack growth