Micromechanisms of fatigue crack nucleation and short crack growth in a low carbon steel under low cycle impact fatigue loading

1999 ◽  
Vol 21 (8) ◽  
pp. 823-830 ◽  
Author(s):  
M Zhang
Keyword(s):  
Fatigue Crack ◽  
Carbon Steel ◽  
Crack Growth ◽  
Crack Nucleation ◽  
Low Carbon Steel ◽  
Fatigue Loading ◽  
Short Crack ◽  
Low Carbon ◽  
Impact Fatigue ◽  
Fatigue Crack Nucleation

scholarly journals Effect of water flow and depth on fatigue crack growth rate of underwater wet welded low carbon steel SS400

2021 ◽  
Vol 11 (1) ◽  
pp. 329-338 ◽  
Author(s):  
E. Surojo ◽  
J. Anindito ◽  
F. Paundra ◽  
A. R. Prabowo ◽  
E. P. Budiana ◽  
...  
Keyword(s):  
Growth Rate ◽  
Fatigue Crack ◽  
Carbon Steel ◽  
Crack Growth Rate ◽  
Crack Growth ◽  
Water Flow ◽  
Water Depth ◽  
Water Flow Rate ◽  
Low Carbon Steel ◽  
Low Carbon

Abstract Underwater wet welding (UWW) is widely used in repair of offshore constructions and underwater pipelines by the shielded metal arc welding (SMAW) method. They are subjected the dynamic load due to sea water flow. In this condition, they can experience the fatigue failure. This study was aimed to determine the effect of water flow speed (0 m/s, 1 m/s, and 2 m/s) and water depth (2.5 m and 5 m) on the crack growth rate of underwater wet welded low carbon steel SS400. Underwater wet welding processes were conducted using E6013 electrode (RB26) with a diameter of 4 mm, type of negative electrode polarity and constant electric current and welding speed of 90 A and 1.5 mm/s respectively. In air welding process was also conducted for comparison. Compared to in air welded joint, underwater wet welded joints have more weld defects including porosity, incomplete penetration and irregular surface. Fatigue crack growth rate of underwater wet welded joints will decrease as water depth increases and water flow rate decreases. It is represented by Paris's constant, where specimens in air welding, 2.5 m and 5 m water depth have average Paris's constant of 8.16, 7.54 and 5.56 respectively. The increasing water depth will cause the formation of Acicular Ferrite structure which has high fatigue crack resistance. The higher the water flow rate, the higher the welding defects, thereby reducing the fatigue crack resistance.

Microstructural fatigue crack growth in single-packet structures of ultra-low carbon steel lath martensite

2019 ◽  
Vol 173 ◽  
pp. 80-85 ◽  
Author(s):  
Shohei Ueki ◽  
Takuya Matsumura ◽  
Yoji Mine ◽  
Shigekazu Morito ◽  
Kazuki Takashima
Keyword(s):  
Fatigue Crack ◽  
Carbon Steel ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Lath Martensite ◽  
Low Carbon Steel ◽  
Low Carbon ◽  
Ultra Low Carbon Steel

Temperature Dependence of Fatigue Crack Growth in Low-Carbon Steel Under Gaseous Hydrogen

2019 ◽  
Author(s):  
Osamu Takakuwa ◽  
Yuhei Ogawa ◽  
Saburo Okazaki ◽  
Hisao Matsunaga ◽  
Saburo Matsuoka
Keyword(s):  
Fatigue Crack ◽  
Carbon Steel ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Low Carbon Steel ◽  
Gaseous Hydrogen ◽  
Low Carbon ◽  
Hydrogen Environment ◽  
Crack Wake ◽  
Higher Temperature

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).

Fatigue crack growth under residual stress field in low-carbon steel

1986 ◽  
Vol 94 (3) ◽  
pp. 241-247 ◽  
Author(s):  
H. Nakamura ◽  
E. Matsushima ◽  
A. Okamoto ◽  
T. Umemoto
Keyword(s):  
Residual Stress ◽  
Fatigue Crack ◽  
Carbon Steel ◽  
Fatigue Crack Growth ◽  
Stress Field ◽  
Crack Growth ◽  
Low Carbon Steel ◽  
Low Carbon ◽  
Residual Stress Field
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