Detail publikace
The Effect of Prior Surface Roughness on Fatigue Life of Nitrided Specimens
KIANICOVÁ, M. ŠANDERA, P. HORNÍKOVÁ, J. KOTTFER, D. POKLUDA, J.
Anglický název
The Effect of Prior Surface Roughness on Fatigue Life of Nitrided Specimens
Typ
článek ve sborníku ve WoS nebo Scopus
Jazyk
en
Originální abstrakt
The effect of surface roughness of virgin specimens (prior roughness) made of low- alloyed high strength steel on their fatigue life after the case-hardening treatment was studied by rotating bending tests of virgin and nitrided samples. In a whole range of S-N curves, the fatigue strength of virgin samples after lathe-turning machining (high roughness) was naturally much higher than that of samples after grinding (low roughness). As expected, the fatigue strength of nitrided specimens was higher than that of virgin samples when averaged through the whole fatigue life range. When distinguishing the rough and smooth nitrided samples, the low-cycle fatigue strength of rough samples revealed to be lower than that of the smooth ones and vice a versa in the high-cycle region. This could be explained by the fact that, in the low cycle region, the cracks in the rough samples nucleated from deep surface defects while, in the smooth specimens, they nucleated from shallow defects (or as fish eyes) which prolonged their initiation stage. Almost all cracks in the high cycle region initiated as fish-eyes but the extent of nitrided layers in the rough specimens was slightly higher than that in the smooth specimens. Therefore, the fish-eye centers were shifted further to the interior of the rough specimens which increased their fatigue life.
Anglický abstrakt
The effect of surface roughness of virgin specimens (prior roughness) made of low- alloyed high strength steel on their fatigue life after the case-hardening treatment was studied by rotating bending tests of virgin and nitrided samples. In a whole range of S-N curves, the fatigue strength of virgin samples after lathe-turning machining (high roughness) was naturally much higher than that of samples after grinding (low roughness). As expected, the fatigue strength of nitrided specimens was higher than that of virgin samples when averaged through the whole fatigue life range. When distinguishing the rough and smooth nitrided samples, the low-cycle fatigue strength of rough samples revealed to be lower than that of the smooth ones and vice a versa in the high-cycle region. This could be explained by the fact that, in the low cycle region, the cracks in the rough samples nucleated from deep surface defects while, in the smooth specimens, they nucleated from shallow defects (or as fish eyes) which prolonged their initiation stage. Almost all cracks in the high cycle region initiated as fish-eyes but the extent of nitrided layers in the rough specimens was slightly higher than that in the smooth specimens. Therefore, the fish-eye centers were shifted further to the interior of the rough specimens which increased their fatigue life.
Klíčová slova anglicky
Nitriding, Surface roughness, Fatigue life, Fish-eye cracks, Surface cracks.
Vydáno
16.11.2020
Nakladatel
TransTech Publication
Místo
Švýcarsko
ISBN
978-3-0357-1612-2
ISSN
1662-9507
Kniha
Metallography XVII
Ročník
405
Číslo
1
Strany od–do
271–276
Počet stran
6
BIBTEX
@inproceedings{BUT161716,
author="Marta {Kianicová} and Pavel {Šandera} and Jana {Horníková} and Jaroslav {Pokluda},
title="The Effect of Prior Surface Roughness on Fatigue Life of Nitrided Specimens",
booktitle="Metallography XVII",
year="2020",
volume="405",
number="1",
month="November",
pages="271--276",
publisher="TransTech Publication",
address="Švýcarsko",
isbn="978-3-0357-1612-2",
issn="1662-9507"
}