Effects of large amounts of hydrogen on the fatigue crack growth behavior of torsional prestrained carbon steel
Journal Title: Frattura ed Integrità Strutturale - Year 2016, Vol 10, Issue 35
Abstract
The effects of large amounts of hydrogen on the fatigue crack growth properties of torsional prestrained ferritic–pearlitic low-carbon steel were investigated. Hydrogen-precharged specimens were produced by conducting cathodic charge to the virgin material and to torsional prestrained JIS-S10C and JISS25C steels (hereafter S10C and S25C steels). Rotating bending fatigue tests were conducted in air at room temperature. Hydrogen content, CH, increased with torsional prestrain for both S10C and S25C steels; the CH of the torsional prestrained S25C steel precharged with hydrogen was lower than that of S10C at the same torsional prestrain. No clear difference between the maximum CH values of the torsional fractured S10C and S25C hydrogen-precharged steel specimens. With respect to crack initiation, there was no obvious difference between the uncharged and precharged specimens in spite of the large amount of CH induced by torsional prestrain. The acceleration of fatigue crack growth by hydrogen was the main cause of the decreased fatigue life. For the virgin material, hydrogen had no obvious effect on the fatigue crack growth rate. In contrast, for the torsional prestrained materials, the acceleration ratios, {(da/dN)H/(da/dN)U}, increased with the torsional prestrain and CH. However, {(da/dN)H/(da/dN)U} did not exceed the value of about 30, even when a large amount of hydrogen was charged (10.0 ≤ CH ≤ 30.3 mass ppm). A hydrogen content threshold was found; hydrogen content above this limit enhances the growth of the non-propagated crack, even for metals with lower hardness (HV < 200).
Authors and Affiliations
Yuta Matsuda, Hiroshi Nishiguchi, Takayuki Fukuda
Keywords
Related Articles
- EP ID EP106731
- DOI 10.3221/IGF-ESIS.35.01
- Views 71
- Downloads 0
A finite-element approach for the analysis of pin-bearing failure ofcomposite laminates
In this paper, a numerical home-made finite element model for the failure analysis of bolted jointsbetween fiber-reinforced composite laminates is presented. The model is based on an incremental displacementbasedap...
Surface crack growth in cylindrical hollow specimen subject to tension and torsion
The subject for studies is an aluminium cylindrical hollow specimen with external axial and part circumferential semi-elliptical surface crack undergoing fatigue loads. Both the optical microscope measurements an...
Crack paths in smooth and precracked specimens subjected to multiaxial cyclic stressing
The understanding of shear-mode crack growth mechanisms and crack branching phenomena is of great interest for a variety of practical engineering situations. Despite this fact, relatively little research is a...
Fatigue failure of welded connections at orthotropic bridges
Orthotropic decks were applied to the long span bridges after World War II due to several advantages, such as light weight, high strength, few deck joints, durability, rapid construction, life-cycle economy. The fatigue...
Evaluation of the material’s damage in gas turbine rotors by instrumented spherical indentation
Experimental indentations are carried out on items of two different materials, taken in several location of various components from high pressure gas turbine rotor which have seen an extensive service. The compon...