The effects of heat treatment on fracture toughness and fatigue crack growth Rates in 440C and BG42 steels

1983 ◽  
Vol 14 (9) ◽  
pp. 1899-1906 ◽  
Author(s):  
Bingzhe Lou ◽  
B. L. Averbach
Keyword(s):  
Heat Treatment ◽  
Fracture Toughness ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Growth Rates ◽  
Crack Growth Rates

Fatigue crack growth of 42CrMo4 and 41Cr4 steels under different heat treatment conditions

2018 ◽  
Vol 9 (3) ◽  
pp. 326-336 ◽  
Author(s):  
Grzegorz Lesiuk ◽  
Monika Maria Duda ◽  
José Correia ◽  
Abilio M.P. de Jesus ◽  
Rui Calçada
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Growth Rates ◽  
Microstructural Properties ◽  
Content Type ◽  
Paris Law ◽  
Crack Growth Rates

Purpose For nowadays construction purposes, it is necessary to define the life cycle of elements with defects. As steels 42CrMo4 and 41Cr4 are typical materials used for elements working under fatigue loading conditions, it is worth to know how they will behave after different heat treatment. Additionally, typical mechanical properties of material (hardness, tensile strength, etc.) are not defining material’s fatigue resistance. Therefore, it is worth to compare, except mechanical properties, microstructure of the samples after heat treatment as well. The paper aims to discuss these issues. Design/methodology/approach Samples of normalized 42CrMo4 (and 41Cr4) steel were heat treated under three different conditions. All heat treatments were designed in order to change microstructural properties of the material. Fatigue tests were carried out according to ASTM E647-15 standard using compact tension specimens. Later on, based on obtained results, coefficients C and m of Paris’ Law for all specimens were estimated. Similar procedure was performed for 41Cr4 steel after quenching and tempering in different temperatures. Findings The influence of heat treatment on the fatigue crack growth rates (42CrMo4, 41Cr4 steel) has been confirmed. The higher fatigue crack growth rates were observed for lower tempering temperatures. Originality/value This study is associated with influence of microstructural properties of the material on its’ fatigue fracture. The kinetic fatigue fracture diagrams have been constructed. For each type of material (and its heat treatment), the Paris law constants were determined.

scholarly journals Effect of Heat-Treatment Upon the Fatigue-Crack Growth Behavior of Alloy 718 Weldments—Part I: Macroscopic Behavior

1985 ◽  
Vol 107 (1) ◽  
pp. 34-40 ◽  
Author(s):  
L. A. James ◽  
W. J. Mills
Keyword(s):  
Heat Treatment ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Growth Rates ◽  
Crack Growth Behavior ◽  
Alloy 718 ◽  
Gas Tungsten Arc ◽  
Increasing Temperature ◽  
Crack Growth Rates

Gas-tungsten-arc weldments in Alloy 718 were studied in fatigue-crack growth tests conducted at five temperatures over the range 24–649°C. In general, crack growth rates increased with increasing temperature, and weldments given the “conventional” post-weld heat-treatment generally exhibited crack growth rates that were higher than for weldments given the “modified” (INEL) heat-treatment. Limited testing in the as-welded condition revealed crack growth rates significantly lower than observed for the heat-treated cases, and this was attributed to residual stresses. Three different heats of filler wire were utilized, and no heat-to-heat variations were noted.

Fracture Mechanics Parameters for a 5083-0 Aluminum Alloy at Low Temperatures

1977 ◽  
Vol 99 (4) ◽  
pp. 306-312 ◽  
Author(s):  
R. L. Tobler ◽  
R. P. Reed
Keyword(s):  
Fracture Toughness ◽  
Aluminum Alloy ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Growth Rates ◽  
Rolling Direction ◽  
Integral Test ◽  
Alloy Plate ◽  
Crack Growth Rates

The fatigue crack growth and fracture resistance of a 5083-0 aluminum alloy plate were investigated at four temperatures in the ambient-to-cryogenic range—295, 111, 76, and 4 K. J-integral test methods were applied using compact specimens 3.17 cm thick, and the value of J required to initiate crack extension (JIc) is reported as an index of fracture toughness. The fracture toughness was orientation dependent, with anisotropy accounting for JIc variations of up to a factor of 2. For specimens having fracture planes parallel to the rolling direction, JIc increases progressively from 9 to 25 kJm−2 as temperature decreases between 295 and 4 K. In contrast, the fatigue crack growth rates (da/dN) are insensitive to specimen orientation. The fatigue crack growth rates at cryogenic temperatures are up to 10 times lower than in air at room temperature, but are virtually constant between 111 and 4 K.

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