Abnormality in using cyclic fatigue for ranking static fatigue induced slow crack growth behavior of polyethylene pipe grade resins

2016 ◽  
Vol 55 ◽  
pp. 101-108
Author(s):  
Hyunmin Bae ◽  
Kyongyoon Lee ◽  
Sooho Pyo ◽  
Sunwoong Choi
Keyword(s):  
Crack Growth ◽  
Slow Crack Growth ◽  
Cyclic Fatigue ◽  
Growth Behavior ◽  
Crack Growth Behavior ◽  
Static Fatigue ◽  
Polyethylene Pipe

scholarly journals Fatigue Crack Growth Behavior of the MIG Welded Joint of 06Cr19Ni10 Stainless Steel

Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1336 ◽  
Author(s):  
Lanqing Tang ◽  
Caifu Qian ◽  
Ayhan Ince ◽  
Jing Zheng ◽  
Huifang Li ◽  
...  
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Fracture Morphology ◽  
Cyclic Fatigue ◽  
Growth Behavior ◽  
Crack Growth Behavior ◽  
Fatigue Crack Growth Behavior

In this paper, the fatigue crack growth behavior of the base metal (BM), the weld metal (WM) and the heat-affected zone (HAZ) in the metal-inert gas (MIG) welded joints of the 06Cr19Ni10 stainless steel are analyzed and studied. Results of the fatigue crack propagation tests show that a new fatigue crack initiates at the crack tip of a pre-existing crack, then propagates perpendicular to the direction of cyclic fatigue loads. This observation indicates that the original mixed-mode crack transforms into the mode I crack. The WM specimen has the largest fatigue crack growth rate, followed by the HAZ specimen and the BM specimen. To illustrate the differences in fatigue crack growth behavior of the three different types of specimens, metallographic structure, fracture morphology and residual stresses of the BM, HAZ and WM are investigated and discussed. The metallographic observations indicate that the mean grain size of the HAZ is relatively larger than that of the BM. The fractographic analysis shows that the WM has the largest fatigue striation width, followed by the HAZ and the BM. It is also found that the depth of dimple in the WM is relatively shallower than the one in the HAZ and BM, implying the poor plasticity behavior of the material. Analysis results of the residual stress analysis demonstrate a high level of tensile residual stress appearance in the WM and HAZ.

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