Modeling of fatigue crack growth in a pressure vessel steel Q345R

2015 ◽  
Vol 135 ◽  
pp. 245-258 ◽  
Author(s):  
Zhenyu Ding ◽  
Zengliang Gao ◽  
Xiaogui Wang ◽  
Yanyao Jiang
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Pressure Vessel ◽  
Pressure Vessel Steel ◽  
Vessel Steel

The Effect of Specimen Thickness Upon the Fatigue Crack Growth Rate of A516-60 Pressure Vessel Steel

1977 ◽  
Vol 99 (2) ◽  
pp. 248-252 ◽  
Author(s):  
A. M. Sullivan ◽  
T. W. Crooker
Keyword(s):  
Growth Rate ◽  
Fatigue Crack ◽  
Crack Growth Rate ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Fatigue Crack Growth Rate ◽  
Pressure Vessel ◽  
Specimen Thickness ◽  
Pressure Vessel Steel ◽  
Vessel Steel

Fatigue crack growth rate studies on A516-60 pressure vessel steel indicate no effect of specimen thickness in stress-relieved specimens ranging in thickness from 0.25 to 2.0 in. (6.35 to 50.8 mm). A regression curve equation for all thicknesses relating cyclic crack growth rate (da/dN) to crack-tip stress-intensity factor range (ΔK) is obtained. The significance of these results is discussed in the light of current engineering practice and previous studies on size effects in fatigue crack propagation.

scholarly journals Fatigue Crack Growth Testing of Sub-Clad Defects

1999 ◽  
Vol 121 (3) ◽  
pp. 269-275 ◽  
Author(s):  
D. P. Jones ◽  
T. R. Leax
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Pressure Vessel ◽  
Fatigue Testing ◽  
Repair Process ◽  
Pressure Vessel Steel ◽  
Vessel Steel ◽  
Point Bend ◽  
Fatigue Crack Growth Testing

Fatigue crack growth tests were performed on four-point bend specimens with cracklike defects intentionally placed in A302B low-alloy pressure vessel steel clad with 308/309L weld-deposited stainless steel. The defects were placed in the base metal under the cladding by machining a cavity from the side opposite the cladding, electric-discharge machining a very sharp flaw, fatigue precracking the flaw, and then filling up the cavity by a weld repair process. The specimens were stress relieved before fatigue testing. The specimens were fatigue cycled at positive load ratios until the defects broke through to the surface. The specimens were then fractured at liquid nitrogen temperatures to reveal the fracture surfaces. Seven different sub-clad flaw specimens were tested in room temperature air and each test provides a record of cycles to defect breakthrough. Changes in defect size and shape as a function of applied load cycles were obtained by beach-marking the crack at various stages of the load history. The results provide a set of embedded defect data which can be used for qualifying fatigue crack growth analysis procedures such as those in Section XI of the ASME Boiler and Pressure Vessel Code. A comparison between calculated and measured values shows that the ASME B&PV Section XI fatigue crack growth procedures conservatively predict cycles to defect breakthrough for small sub-clad defects.

Near-Threshold Fatigue Crack Growth in 2 1/4 Cr-1Mo Pressure Vessel Steel in Air and Hydrogen

1980 ◽  
Vol 102 (3) ◽  
pp. 293-299 ◽  
Author(s):  
R. O. Ritchie ◽  
S. Suresh ◽  
C. M. Moss
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Propagation ◽  
Crack Growth ◽  
Growth Rates ◽  
Pressure Vessel ◽  
Pressure Vessel Steel ◽  
Vessel Steel ◽  
Argon Gas ◽  
Near Threshold

As part of an ongoing program to examine subcritical flaw growth in candidate steels for proposed coal gasifier pressure vessels, an initial study is made of characteristics of ultralow growth rate fatigue crack propagation in thick-section, normalized 2 1/4 Cr-1Mo pressure vessel steel (ASTM A387, Class 2 Grade 22). Crack propagation data are generated over a wide range of growth rates, from 10−8 to 10−2 mm/cycle, for load ratios between 0.05 and 0.80 at ambient temperatures in low pressure environments of moist air, dry hydrogen gas and dry argon gas. Particular emphasis is placed on behavior at near-threshold growth rates, below 10−6 mm/cycle, approaching the so-called threshold stress intensity for fatigue crack growth, ΔK0. Near-threshold growth rates, in addition to showing a marked sensitivity to load ratio, are found to be significantly enhanced in gaseous hydrogen compared to air. Similar environmentally-enhanced growth is observed in argon gas. To account for such results, previous models of threshold behavior based on environmental factors (e.g., hydrogen embrittlement) are questioned, and a new approach is presented in terms of the role of oxide debris from moist environments in promoting crack closure. This oxide-induced closure model is found to be consistent with most experimental observations of near-threshold fatigue crack propagation behavior and is proposed as a mechanism for environmental effects at ultra-low growth rates.

An Experimental Study of Fatigue Crack Propagation of 16MnR Pressure Vessel Steel in Mode-I Constant Amplitude Loading

2012 ◽  
Vol 455-456 ◽  
pp. 1073-1078
Author(s):  
Wen Feng Tu ◽  
Zeng Liang Gao ◽  
Zhao Ji Hu
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Crack Front ◽  
Stress Ratio ◽  
Mode I ◽  
Specimen Thickness ◽  
Pressure Vessel Steel ◽  
Constant Amplitude ◽  
Vessel Steel

An experimental investigation was performed on fatigue crack growth behavior of a 16MnR pressure vessel steel. Standard compact tension (CT) specimens with three specimen thicknesses and notch sizes were subjected to Mode I constant amplitude loading with several stress ratios and loading amplitudes. The results revealed that the stress ratio had an insignificant influence on the fatigue crack growth of the material. The stable fatigue crack growth rate (FCGR) was accelerated as specimen thickness increased. The fatigue crack was extended in terms of the curve crack shape. The crack front at the surface was retarded compared to that at the interior along thickness direction, and the crack front at the mid-thickness plane reached the maximum value of the crack length. The similar curve crack shape was obtained in the stable crack growth stage. The maximum difference of the crack front along thickness direction was increased with the increasing of the specimen thickness. The early crack growth from the notch was effected by the size of the notch, the stress ratio and loading amplitude.

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