Evaluation of Creep-Fatigue Crack Growth for Grade 91 Steel Wide Plate

2010 ◽  
Vol 654-656 ◽  
pp. 528-531 ◽  
Author(s):  
Hyeong Yeon Lee ◽  
Jong Bum Kim ◽  
Jae Han Lee
Keyword(s):  
Stainless Steel ◽  
Fatigue Crack ◽  
Austenitic Stainless Steel ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Defect Assessment ◽  
Creep Fatigue ◽  
Grade 91 ◽  
Creep Fatigue Crack ◽  
Grade 91 Steel

An assessment of a creep-fatigue crack growth for Mod. 9Cr-1Mo steel wide plates have been carried out based on an extended French high temperature design code, RCC-MR A16 guide. The defect assessment guide of the A16 provides assessment procedures on creep-fatigue crack growth for an austenitic stainless steel, but no guidelines are available yet for a Mod. 9Cr-1Mo steel. In this study, assessments of a creep-fatigue crack growth at defects of Grade 91 steel wide plates have been carried out based on the extended A16 method for austenitic stainless steel.

A French Guideline for Defect Assessment at Elevated Temperature and Leak Before Break Analysis

2003 ◽  
Author(s):  
Y. Kayser ◽  
S. Marie ◽  
M. H. Lacire ◽  
S. Chapuliot ◽  
B. Drubay
Keyword(s):  
Fatigue Crack ◽  
Elevated Temperature ◽  
Fatigue Crack Growth ◽  
Crack Initiation ◽  
Crack Growth ◽  
Characteristic Distance ◽  
Defect Assessment ◽  
Creep Fatigue ◽  
Creep Fatigue Crack ◽  
Leak Before Break

A large program is performed in France in order to develop, for the design and operating FBR plants, defect assessment procedures and Leak-Before-Break methods (L.B.B.). The main objective of this A16 guide is to propose analytical solutions at elevated temperature coherent with those proposed at low temperature by the RSE-M (RSE-M, 1997). The main items developed in this A16 guide for laboratory specimen, plates, pipes and elbows are the following: • Evaluation of ductile crack initiation and crack propagation based on the J parameter and material characteristics as JR-Δa curve or Ji / Gfr. Algorithms to evaluate the maximum endurable load under increasing load for through wall cracks or surface cracks are also proposed. • Determination of fatigue or creep-fatigue crack initiation based on the σd approach calculating stress and strain at a characteristic distance d from the crack tip. • Evaluation of fatigue crack growth based on da/dN-ΔKeff relationship with a ΔKeff derived from a simplified estimation of ΔJ for the cyclic load. • Evaluation of creep-fatigue crack growth adding the fatigue crack growth and the creep crack growth during the hold time derived from a simplified evaluation of C*. • Leak-Before-Break procedure. The fracture mechanic parameters determined in the A16 guide (KI, J, C*) are derived from handbooks and formula in accordance with those proposed in the RSE-M document for in service inspection. Those are: • The KI handbook for a large panel of surface and through-wall defects in plates, pipes and elbows. • Elastic stress and reference stress formula. • Analytical Js and Cs* formulations for mechanical and through thickness thermal load. The main part of the formula and assessment methodologies proposed in the A16 guide are included in a software, called MJSAM, developed under the MS Windows environment in support of the document. This allows a simple application of the analysis proposed in the document.

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