The Effects of Material Strength, Stress Ratio, and Compressive Overload on the Threshold Behavior of a SAE1045 Steel

1985 ◽  
Vol 107 (1) ◽  
pp. 19-25 ◽  
Author(s):  
M. T. Yu ◽  
T. H. Topper
Keyword(s):  
Mechanical Properties ◽  
Growth Rate ◽  
Threshold Stress ◽  
Stress Ratio ◽  
Peak Load ◽  
Load Level ◽  
Material Strength ◽  
Threshold Stress Intensity ◽  
Threshold Behavior ◽  
Rate Behavior

The fatigue crack growth rate behavior of a SAE1045 steel in the as received condition and four different quenched and tempered conditions was studied as a function of stress ratio and peak compressive overload. The threshold stress intensity behavior of the quenched and tempered conditions was not sensitive to changes of monotonic mechanical properties. The threshold decreased linearly with increasing positive stress ratio and compressive peak load level. As received ferritic-pearlitic SAE1045 steel was much more sensitive to stress ratio and compressive peak load than any of the quenched and tempered conditions studied.

Some Applications of Fractal Fracture Mechanics to Describe the Fatigue Behaviour of Materials

2008 ◽  
Vol 378-379 ◽  
pp. 355-370 ◽  
Author(s):  
Andrea Carpinteri ◽  
Andrea Spagnoli ◽  
Sabrina Vantadori
Keyword(s):  
Growth Rate ◽  
Fatigue Crack ◽  
Stress Intensity ◽  
Crack Growth Rate ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Fatigue Limit ◽  
Threshold Stress ◽  
Threshold Stress Intensity ◽  
Stress Intensity Range

As is well-known, fatigue limit, threshold stress intensity range and fatigue crack growth rate are influenced by the specimen or structure size. Limited information on size effect is available in the literature. In the present paper, by employing some concepts of fractal geometry, new definitions of fatigue limit, fracture energy and stress intensity factor, based on physical dimensions different from the classical ones, are discussed. Then, size-dependent laws for fatigue limit, threshold stress intensity range and fatigue crack growth rate are proposed. Some experimental results are examined in order to show how to apply such theoretical scaling laws.

Stress Corrosion Cracking Behavior of 300M Steel under Different Heat Treated Conditions

CORROSION ◽  
1985 ◽  
Vol 41 (12) ◽  
pp. 688-699 ◽  
Author(s):  
R. Padmanabhan ◽  
W. E. Wood
Keyword(s):  
Heat Treatment ◽  
Growth Rate ◽  
Stress Intensity ◽  
Crack Growth Rate ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Threshold Stress ◽  
Corrosion Cracking ◽  
Threshold Stress Intensity ◽  
300M Steel

Abstract The resistance of 300M steel to stress corrosion cracking in a 3.5% NaCl solution was studied as a function of heat treatment. Threshold stress intensity was affected by microstructural features, including prior austenite grain size, amounts of retained austenite, and twins, in addition to grain boundary segregation and fracture toughness of the steel. Crack growth rate was also dependent on microstructure and segregation, but the number of constraint points exerted the maximum influence. The effect of a modified heat treatment, which has been shown to improve all investigated mechanical properties to a significant extent, upon stress corrosion cracking (SCC) properties, was also studied. This heat treatment resulted in significantly higher threshold stress intensity and lower crack growth rate. The results are discussed in terms of microstructure and fractography.

Threshold Stress Intensity Factor (Kth) in Inertial Effect Coefficient Model

2011 ◽  
Vol 197-198 ◽  
pp. 1452-1459 ◽  
Author(s):  
Li Xiong Gu ◽  
Zhi Fang Liu ◽  
Zhong Yong Xu
Keyword(s):  
Growth Rate ◽  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Threshold Stress ◽  
Inertial Effect ◽  
Threshold Stress Intensity ◽  
Threshold Stress Intensity Factor ◽  
Static Fracture ◽  
Good Agreement

In this paper we first review the inertial effect coefficient model for fatigue crak growth (FCG) under constant amplitude (CA) loading based on static fracture mechanics with thinking about the inertial effect coefficient and its impact to crack tip, and then discuss the relation between threshold stress intensity factor (Kth) and fatigue crak growth rate, which is in good agreement with the result by analysing the relation between dynamical coefficient and fatigue crak growth rate. Comparison of the present analysis with experimental data taken from the literature demonstrates that threshold stress intensity factor (Kth) has a greater impact to the fatigue crack propagation.

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