Comparison of techniques for the measurement of plastic work of fatigue crack growth in low carbon steel

1985 ◽  
Vol 21 (1) ◽  
pp. 63-74 ◽  
Author(s):  
A.D. Joseph ◽  
T.S. Gross
2019 ◽  
Vol 173 ◽  
pp. 80-85 ◽  
Author(s):  
Shohei Ueki ◽  
Takuya Matsumura ◽  
Yoji Mine ◽  
Shigekazu Morito ◽  
Kazuki Takashima

Author(s):  
Osamu Takakuwa ◽  
Yuhei Ogawa ◽  
Saburo Okazaki ◽  
Hisao Matsunaga ◽  
Saburo Matsuoka

Abstract In order to elucidate the temperature dependence of hydrogen-assisted fatigue crack growth (HAFCG), the fatigue crack growth (FCG) test was performed on low-carbon steel JIS-SM490B according to ASTM E647 using compact tension (CT) specimen under 0.7 MPa (≈ 0.1 ksi) hydrogen-gas at room temperature (RT: 298 K (≈ 77 °F)) and 423 K (≈ 302 °F) at stress intensity factor range of ΔK = 30 MPa m1/2 (≈ 27 ksi in1/2). Electron backscatter diffraction (EBSD) observation was performed on the mid-thick section of CT specimen in order to investigate change in plasticity around the crack wake in gaseous hydrogen environment and how it changes due to temperature elevation. The obtained results showed the higher temperature, the lower intense of HAFCG as reported in our previous article. Plasticity around the crack wake became less in gaseous hydrogen environment, especially tested at 298 K. The propensity of the results obtained at higher temperature (423 K) can be separated into two cases: (i) intense plasticity occurs like tested in air, (ii) crack propagates straighter accompanying less plasticity like tested in gaseous hydrogen environment at 298 K. This implies macroscopic FCG rate is determined by combination of microscopic FCG rate in the case (i) and case (ii).


1986 ◽  
Vol 94 (3) ◽  
pp. 241-247 ◽  
Author(s):  
H. Nakamura ◽  
E. Matsushima ◽  
A. Okamoto ◽  
T. Umemoto

Author(s):  
Akihide Nagao ◽  
Shuai Wang ◽  
Kelly E. Nygren ◽  
Mohsen Dadfarnia ◽  
Petros Sofronis ◽  
...  

The effect of external high-pressure H2 gas on fatigue-crack growth behavior has been examined using a ferritic-pearlitic low carbon steel. The presence of hydrogen accelerates the crack growth rate by ≈13 times compared to the uncharged state and shifts the fracture surface morphology from ductile striations to a mixture of “flat” and “quasi-cleavage” features. The common feature found in the microstructure immediately beneath the hydrogen-induced fracture surface is enhanced plasticity in terms of refined dislocation cell structures and dense dislocation bands.


2007 ◽  
Vol 567-568 ◽  
pp. 329-332 ◽  
Author(s):  
Kyohei Kawamoto ◽  
Yasuji Oda ◽  
Hiroshi Noguchi

In order to investigate the hydrogen effect on fatigue crack growth (FCG) behavior in a few kinds of practical alloys; austenitic stainless steels (solution-treated metastable type 304 and stable type 316L), an aluminum alloy (age-hardened 6061) and a low carbon steel (annealed 0.13%C-Fe), FCG tests were carried out in hydrogen gas and in nitrogen gas. The FCG rates of these materials are enhanced by hydrogen, though the acceleration degrees are different. A crack grows across grains by slip-off in 316L stainless steel and in age-hardened 6061 aluminum alloys even in hydrogen. Faceted area increases in 304 stainless steel and in low carbon steel in hydrogen. In 304 stainless steel, the ratio of facets to the entire fracture surface was not so large. Thus, the FCG rate is not significantly affected through the facets in 304 stainless steel. In low carbon steel, facets were increased considerably, though a crack grows step by step or after a large number of loading cycles even along grain boundaries. Anyhow hydrogen enhances the FCG rate of these materials through the influence on slip behavior. Based on above-mentioned results, the effect of loading frequency on FCG rate in hydrogen of the age-hardened 6061 aluminum alloy was also investigated. The FCG rate increases as the testing frequency decreases, though the FCG rate in hydrogen shows the tendency to saturate.


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