Fatigue Strength of Radical Nitrided Bearing Steel.
Fatigue Strength of Radical Nitrided Bearing Steel.
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自由基渗氮轴承钢的疲劳强度。
DOI：
10.1299/kikaia.66.2036
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发表时间：
2000
期刊：
影响因子：
--
通讯作者：
K. Fukada
中科院分区：
文献类型：
--
作者：
N. Kawagoishi;K. Morino;Takenori Oka;Nobuaki Tanaka;K. Fukada
为了明确自由基渗氮对疲劳强度和鱼眼断裂寿命区断裂机制的影响，对高碳铬钢进行了旋转弯曲疲劳试验。研究发现，在调质钢和氮化钢中，裂纹的萌生源于高应力水平下的滑移或表面缺陷，以及低应力水平下的内部缺陷。然而，氮化钢的鱼眼断裂区域的疲劳寿命比调质钢的要短得多。在鱼眼非金属夹杂物周围，在调质钢中观察到颗粒状刻面，但在氮化钢中观察到无特征刻面。鱼眼断口的宏观观察还表明，在调质钢中，裂纹从鱼眼处开始急剧扩展，而在氮化钢中，裂纹在扩散层内迅速生长，然后从整个扩散层向内延伸，形成环形断口。
Rotating bending fatigue tests were performed for a high carbon-chromium steel in order to clarify the influence of radical nitriding on fatigue strength and fracture mechanism in the life region where a fish-eye fracture occurs. It was found that crack intiation originated from slips or surface defects under high stress levels and from internal defects under low stress levels in the both quenched and tempered steel and nitrided steel. However, fatigue life in the fish-eye fracture region was extremely shorter in the nitrided steel than in the quenched and tempered steel. Around the non-metallic inclusion of fish-eye, granular facets were observed in the quenched and tempered steel but in the nitrided steel featureless facets generated. Macroscopic examination of fish-eye fracture surfaces also showed that in the quenched and tempered steel, a crack propagated radically with a start at fish-eye, but in the nitrided steel it grew rapidly within diffusion layer and then extended internally from the whole diffusion layer to form a ring-shaped fracture surface.