Creep-Fatigue Fracture of Dissimilar Metal Electron Beam Welded Joints at Elevated Temperature

1988 ◽  
Vol 110 (3) ◽  
pp. 212-218 ◽  
Author(s):  
M. Okazaki ◽  
Y. Mutoh ◽  
M. Yamaguchi
Keyword(s):  
Electron Beam ◽  
Fatigue Life ◽  
Welded Joints ◽  
Prediction Method ◽  
Strain Range ◽  
Local Strain ◽  
Base Metals ◽  
Dissimilar Metal ◽  
Creep Fatigue ◽  
Metal Electron

Creep-fatigue tests of dissimilar-metal electron beam welded joints between A387 Gr.22 ferritic low-alloy steel and AISI 405 ferritic stainless steel were carried out under strain-controlled cycling at a temperature of 873 K. It was found that the creep-fatigue life of a dissimilar metal welded joint was significantly shorter than those of its base metals. This resulted from the strain concentration on the AISI 405 side (with the lower deformation resistance.) It was also found that the hardness distribution was one of the important measures by which the local strain distribution was reflected. Furthermore, a simple prediction method for the creep-fatigue life of dissimilar metal welded joints was proposed based on the creep-fatigue life properties of its base metals by applying the strain range partitioning approach. The predicted lives were in good agreement with the experimental results.

scholarly journals Creep-fatigue fracture behavior of dissimilar metal electron beam welded joint.

1987 ◽  
Vol 36 (410) ◽  
pp. 1239-1245
Author(s):  
Masakazu OKAZAKI ◽  
Yoshiharu MUTOH ◽  
Toshio YADA ◽  
Masao YAMAGUCHI
Keyword(s):  
Electron Beam ◽  
Fatigue Fracture ◽  
Fracture Behavior ◽  
Welded Joint ◽  
Dissimilar Metal ◽  
Creep Fatigue ◽  
Fatigue Fracture Behavior ◽  
Metal Electron

Life Prediction Method of CC and DS Ni Base Superalloys Under High Temperature Biaxial Fatigue Loading

2010 ◽  
Vol 132 (11) ◽  
Author(s):  
Takashi Ogata
Keyword(s):  
Fatigue Life ◽  
Gas Turbine ◽  
Turbine Blade ◽  
Life Prediction ◽  
Compressive Strain ◽  
Prediction Method ◽  
Strain Range ◽  
Fatigue Loading ◽  
Normal Strain ◽  
Biaxial Fatigue

Polycrystalline conventional casting (CC) and directionally solidified (DS) Ni base superalloys are widely used as gas turbine blade materials. It was reported that the surface of a gas turbine blade is subjected to a biaxial tensile-compressive fatigue loading during a start-stop operation, based on finite element stress analysis results. It is necessary to establish the life prediction method of these superalloys under biaxial fatigue loading for reliable operations. In this study, the in-plane biaxial fatigue tests with different phases of x and y directional strain cycles were conducted on both CC and DS Ni base superalloys (IN738LC and GTD111DS) at high temperatures. The strain ratio ϕ was defined as the ratio between the x and y directional strains at 1/4 cycle and was varied from 1 to −1. In ϕ=1 and −1. The main cracks propagated in both the x and y directions in the CC superalloy. On the other hand, the main cracks of the DS superalloy propagated only in the x direction, indicating that the failure resistance in the solidified direction is weaker than that in the direction normal to the solidified direction. Although the biaxial fatigue life of the CC superalloy was correlated with the conventional Mises equivalent strain range, that of the DS superalloy depended on ϕ. The new biaxial fatigue life criterion, equivalent normal strain range for the DS superalloy was derived from the iso-fatigue life curve on a principal strain plane defined in this study. Fatigue life of the DS superalloy was correlated with the equivalent normal strain range. Fatigue life of the DS superalloy under equibiaxial fatigue loading was significantly reduced by introducing compressive strain hold dwell. Life prediction under equibiaxial fatigue loading with the compressive strain hold was successfully made by the nonlinear damage accumulation model. This suggests that the proposed method can be applied to life prediction of the gas turbine DS blades, which are subjected to biaxial fatigue loading during operation.

scholarly journals Characterising Residual Stresses in a Dissimilar Metal Electron Beam Welded Plate

2015 ◽  
Vol 130 ◽  
pp. 973-985 ◽  
Author(s):  
K. Abburi Venkata ◽  
C.E. Truman ◽  
D.J. Smith
Keyword(s):  
Electron Beam ◽  
Residual Stresses ◽  
Dissimilar Metal ◽  
Metal Electron

scholarly journals Creep-Fatigue Life Prediction for Ligament of Boiler Headers by Strain Range Partitioning Method.

1999 ◽  
Vol 48 (6) ◽  
pp. 604-609 ◽  
Author(s):  
Hiroyuki HAYAKAWA ◽  
Mituo MIYAHARA ◽  
Akihiro KANAYA ◽  
Kazuo OKAMURA
Keyword(s):  
Fatigue Life ◽  
Life Prediction ◽  
Strain Range ◽  
Fatigue Life Prediction ◽  
Creep Fatigue

Verification of the Prediction Methods of Strain Range in Notched Specimens Made of Mod.9Cr-1Mo

2010 ◽  
Author(s):  
Masanori Ando ◽  
Yuichi Hirose ◽  
Shingo Date ◽  
Sota Watanabe ◽  
Yasuhiro Enuma ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Elevated Temperature ◽  
Low Cycle Fatigue ◽  
Strain Range ◽  
Fatigue Tests ◽  
Estimation Methods ◽  
Prediction Methods ◽  
Test Machine ◽  
Notched Specimens ◽  
Creep Fatigue

Several innovative prediction methods of strain range have been developed in order to apply to the Generation IV plants. In a component design at elevated temperature, ‘strain range’ is used to calculate the fatigue and creep-fatigue damage. Therefore, prediction of ‘strain range’ is one of the most important issues to evaluate the components’ integrity during these lifetimes. To verify the strain prediction method of discontinues structures at evaluated temperature, low cycle fatigue tests were carried out with notched specimens. All the specimens were made of Mod.9Cr-1Mo, because it is a candidate material for a primary and secondary heat transports system components of JSFR (Japanese Sodium Fast Reactor). Deformation control fatigue tests and thermal fatigue tests were performed by ordinary uni-axial push-pull test machine and equipment generating the thermal gradient in the notched plate by induction heating. Stress concentration level was changed by varying the notch radius in the both kind of tests. Crack initiation and propagation process during the fatigue test were observed by the digital micro-scope and replica method. Elastic and inelastic FEAs were also carried out to estimate the ‘strain range’ for the prediction of fatigue life. Then the ranges of several strain predictions and estimations were compared with the test results. These predictions were based on the sophisticated technique to estimate the ‘strain range’ from elastic FEA. Stress reduction locus (SRL) method, simple elastic follow-up method, Neuber’s rule method and the methods supplied by elevated temperature design standards were applied. Through these results, the applicability and conservativeness of these strain prediction and estimation methods, which is the basis of the creep-fatigue life prediction, is discussed.

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