Evaluation of Corrosion Fatigue Crack Propagation Characteristics of TMCP Steel in Synthetic Seawater under Cathodic Protection

2007 ◽  
Vol 26-28 ◽  
pp. 1145-1148 ◽  
Author(s):  
Won Beom Kim ◽  
Jeom Kee Paik

In this research, corrosion fatigue tests using tensile strength of 490MPa TMCP steel were performed in synthetic seawater condition to investigate the corrosion fatigue crack propagation characteristics. The influence of cathodic protection at -800mV vs. SCE on the corrosion fatigue crack propagation behavior was investigated. Relationships between da/dN versus ΔK for the material were obtained by two types of test specimens. In the present study, F(α,β) versus α(= 2a/W) relationship for the CCT specimen was calculated by J integral approach, while that for the CT specimen was determined from ASTM E647. It is found that the fatigue crack propagation rate of TMCP steel in synthetic seawater condition is faster than that in air condition at least twice. Also, it is observed that the fatigue crack propagation rate of steel with cathodic protection is in between those of seawater condition without cathodic protection and air condition.

2017 ◽  
Vol 31 (16-19) ◽  
pp. 1744009 ◽  
Author(s):  
Lin Shen ◽  
Hui Chen ◽  
Xiaoli Che ◽  
Lidong Xu

A modified single-edge notch tension (SENT) specimen exposed to saline environment was utilized to investigate the corrosion–fatigue crack growth behaviors of 5083, 6005 and 7N01 aluminum alloys. The fatigue crack propagation life, corrosion–fatigue crack rate ([Formula: see text]) were tested. The microstructures and fracture surfaces of specimens were examined by optical microscopy and scanning electron microscopy (SEM). The results showed that fatigue crack propagation rate of 7N01 in 3.5% NaCl was significantly higher than 6005 and 5083 alloys. The mechanisms of anodic dissolution and hydrogen embrittlement are used to explain the results.


2008 ◽  
Vol 144 ◽  
pp. 90-93 ◽  
Author(s):  
Grzegorz Gasiak ◽  
Grzegorz Robak

The paper presents a test stand for measurements of fatigue crack propagation. The stand includes a fatigue machine MZGS–100 and a device for registration of the crack length. The test stand is equipped with a stereoscopic microscope with fluent magnification of 7× – 67.5×. The microscope can be applied for observation of fatigue crack development. The microscope is also equipped with a digital camera, which enables continuous observation of fatigue crack development on the computer monitor and it is not necessary to stop the machine. The test results obtained at this stand can be used for determination of fatigue life and fatigue crack propagation rate.


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