The Effect of Prior Surface Roughness on Fatigue Life of Nitrided Specimens

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216305%3A26210%2F20%3APU135102" target="_blank" >RIV/00216305:26210/20:PU135102 - isvavai.cz</a>

Výsledek na webu

<a href="http://dx.doi.org/10.4028/www.scientific.net/DDF.405.271" target="_blank" >http://dx.doi.org/10.4028/www.scientific.net/DDF.405.271</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.4028/www.scientific.net/DDF.405.271" target="_blank" >10.4028/www.scientific.net/DDF.405.271</a>

Jazyk výsledku

angličtina

Název v původním jazyce

The Effect of Prior Surface Roughness on Fatigue Life of Nitrided Specimens

Popis výsledku v původním jazyce

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.

Název v anglickém jazyce

The Effect of Prior Surface Roughness on Fatigue Life of Nitrided Specimens

Popis výsledku anglicky

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.

Druh

D - Stať ve sborníku

CEP obor

—

OECD FORD obor

20301 - Mechanical engineering

Projekt

—

Návaznosti

S - Specificky vyzkum na vysokych skolach

Rok uplatnění

2020

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název statě ve sborníku

Metallography XVII

ISBN

978-3-0357-1612-2

ISSN

1662-9507

e-ISSN

—

Počet stran výsledku

6

Strana od-do

271-276

Název nakladatele

TransTech Publication

Místo vydání

Švýcarsko

Místo konání akce

Nový Smokovec

Datum konání akce

24. 4. 2019

Typ akce podle státní příslušnosti

EUR - Evropská akce

Kód UT WoS článku

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