scholarly journals Creep-Fatigue Crack Initiation and Incipient Growth Behavior for Ni-Base Single Crystal Superalloy.

1996 ◽  
Vol 45 (10) ◽  
pp. 1096-1101 ◽  
Author(s):  
Shigeo SAKURAI ◽  
Akira YOSHINARI
Keyword(s):  
Fatigue Crack ◽  
Crack Initiation ◽  
Single Crystal ◽  
Fatigue Crack Initiation ◽  
Growth Behavior ◽  
Single Crystal Superalloy ◽  
Creep Fatigue ◽  
Creep Fatigue Crack

Creep-Fatigue Damage and Crack Initiation for a Mod 9Cr-1Mo Structure With Weldments

2007 ◽  
Author(s):  
Hyeong-Yeon Lee ◽  
Se-Hwan Lee ◽  
Jong-Bum Kim ◽  
Jae-Han Lee
Keyword(s):  
Fatigue Crack ◽  
Crack Initiation ◽  
Fatigue Damage ◽  
Hold Time ◽  
Fatigue Crack Initiation ◽  
Creep Damage ◽  
Steel Specimen ◽  
Structural Test ◽  
Creep Fatigue ◽  
Creep Fatigue Crack

A structural test and evaluation on creep-fatigue damage, and creep-fatigue crack initiation have been carried out for a Mod. 9Cr-1Mo steel structural specimen with weldments. The conservatisms of the design codes of ASME Section III subsection and NH and RCC-MR codes were quantified at the welded joints of Mod.9Cr-1Mo steel and 316L stainless steel with the observed images from the structural test. In creep damage evaluation using the RCC-MR code, isochronous curve has been used rather than directly using the creep law as the RCC-MR specifies. A y-shaped steel specimen of a diameter 500mm, height 440mm and thickness 6.35mm is subjected to creep-fatigue loads with two hours of a hold time at 600°C and a primary nominal stress of 30MPa. The defect assessment procedures of RCC-MR A16 guide do not provide a procedure for Mod.9Cr-1Mo steel yet. In this study application of σd method for the assessment of creep-fatigue crack initiation has been examined for a Mod. 9Cr-1Mo steel structure.

scholarly journals Fatigue crack initiation in a notched single-crystal superalloy component

2010 ◽  
Vol 2 (1) ◽  
pp. 1067-1075 ◽  
Author(s):  
Daniel Leidermark ◽  
Johan Moverare ◽  
Kjell Simonsson ◽  
Sören Sjöström ◽  
Sten Johansson
Keyword(s):  
Fatigue Crack ◽  
Crack Initiation ◽  
Single Crystal ◽  
Fatigue Crack Initiation ◽  
Single Crystal Superalloy

Creep-Fatigue Crack Initiation Assessments of an Instrument Guide Tube Within a Superheater Header

2014 ◽  
Author(s):  
Jinhua Shi ◽  
Hassam Dodia
Keyword(s):  
Fatigue Crack ◽  
Crack Initiation ◽  
Fatigue Damage ◽  
Material Properties ◽  
Fatigue Crack Initiation ◽  
Guide Tube ◽  
New Approach ◽  
Weld Material ◽  
Creep Fatigue ◽  
Creep Fatigue Crack

In order to extend the boiler lives at Advanced Gas-Cooled Reactor (AGR) nuclear power stations in the UK, new temperature measuring instrumentation to monitor reactor gas temperature has been proposed to install on the bore of an intact boiler tube to provide additional boiler operating data to support the station lifetime extension. This paper details a creep-fatigue crack initiation assessment of the proposed installation of an instrument guide tube within the superheater header using the latest R5 high temperature assessment procedures based on detailed finite element thermal transient stress analysis values for a bounding start-up and shutdown cycle. The fatigue damage at welds has been calculated based on both weld and parent material properties. The new approach for assessing weldments has been used in this paper. This new approach involves splitting the existing Fatigue Strength Reduction Factor (FSRF) into a Weldment Endurance Reduction (WER), which accounts for reduced fatigue endurance due to weld imperfections, and a Weldment Strain Enhacement Factor (WSEF), which accounts for material mismatch and local geometry. The creep assessments of the weld material locations have been carried out on both parent and weld material properties including the welding residual stress. The total creep-fatigue damage is then obtained as the sum of fatigue damage, Df, and creep damage, Dc.

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