| Q345E steel is a low alloy steels made in China, because of its good mechanical and welding properties, in many areas has been widely used, but at present of this kind of steel performance research mostly confined to the conventional mechanical properties, welding property and impact toughness and so on, however, as parts breaking an important basis for estimating the design and residual the study of life-the crack growth rate is very rare.The Q345E steel standard compact tension specimens (CT specimens) were tested under constant amplitude fatigue crack growth tests,Mainly carries on the analysis from two aspects of reliability:One,For constant amplitude crack growth tests obtained (a, N) data for statistical analysis:(1)Based on (a, N) data reliability of fatigue crack growth rate;(2) Based on (da/dN,△K) data reliability of fatigue crack growth rate.Two,Considering the influence of the statistical sample size of the data, the fatigue crack growth under different confidence reliability study rate:(1)The confidence is90%and95%, based on (a, N) data reliability of fatigue crack growth rate;(2) Confidence is90%and95%, based on (da/dN,△K) data reliability of fatigue crack growth rate.Obtained through the above research:(1) Q345E steel with different crack reliability growth rate of the Paris formula and p-da/dN-[K curve;(2) Confidence is90%and95%, Q345E steel with different crack growth rate under the reliable degree of the Paris formula and p-γ-da/dN-△K curve.The Q345E steel standard compact tension specimens (CT specimens) for crack growth tests under overload. Analysis of overload on Q345E steel containing crack effect of fatigue life and fatigue crack growth rate of. Scanning electron microscopy of fatigue fracture of Q345E steel (SEM) analysis, study on the mechanism of overload effects on fatigue life and crack growth rate of Q345E.Research shows that, the overload can make the fatigue life of Q345E steel increased, significantly reduces the crack growth rate. |
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