1 State Key Laboratory of Traction Power, Southwest Jiaotong University, Chengdu 610031, China 2 Key Laboratory of Advanced Technologies of Materials(Ministry of Education), Southwest Jiaotong University, Chengdu 610031, China
A series of bending fretting fatigue tests of 18CrNiMo7-6 alloy steel were carried out, the bending fretting fatigue S-N curve was built up, and an analysis was made on the test results. The results show that, the S-N curve of 18CrNiMo7-6 alloy steel presents a shape of "ε" curve, which is different from the medium carbon steel, and also different from the plain bending fatigue. With the increase of the bending fatigue stress, the fretting regime transforms from partial slip regime to mixed regime and slip regime. The wear mechanisms of fretting damage zones mainly are delaminated, abrasive wear and oxidative wear. In the mixed regime, the cracks are easy to initiate and propagate, and the cracks all originate from the subsurface of contact zone. Due to the different influence levels of the contact stress and bending fatigue stress, the initiation and propagation of the bending fretting fatigue cracks can be divided into three stages. Firstly, the cracks initiate from subsurface under the control of contact stress; then propagate to a larger angle direction under the joint control of contact stress and bending fatigue stress; lastly the cracks propagate vertically to contact surface until fracture failure under the control of bending fatigue stress.
SHEN M X , PENG J F , ZHU M H . Study and development of fretting fatigue[J]. Journal of Materials Engineering, 2010, (12): 86- 91.
doi: 10.3969/j.issn.1001-4381.2010.12.019
5
WINKLER J , GEORGAKIS C T , FISCHER G . Fretting fatigue behavior of high-strength steel monostrands under bending load[J]. International Journal of Fatigue, 2015, 70, 13- 23.
doi: 10.1016/j.ijfatigue.2014.08.009
6
ALFREDSSON B . Fretting fatigue of a shrink-fit pin subjected to rotating bending: experiments and simulations[J]. International Journal of Fatigue, 2009, 31 (10): 1559- 1570.
doi: 10.1016/j.ijfatigue.2009.04.019
7
JUUMA T . Torsional fretting fatigue strength of a shrink-fitted shaft with a grooved hub[J]. Tribology International, 2000, 33 (8): 537- 543.
doi: 10.1016/S0301-679X(00)00102-X
FU K , ZHANG K , LING H Q . Crack analysis of output gear shaft of 18CrNiMo7-6 steel[J]. Heat Treatment of Metals, 2011, 36 (Suppl 1): 331- 333.
9
PENG J F , SONG C , ZHU M H . An experimental study on bending fretting fatigue characteristics of 316L austenitic stainless steel[J]. Tribology International, 2011, 44 (11): 1417- 1426.
doi: 10.1016/j.triboint.2010.11.013
10
PENG J F , LIU J H , ZHU M H , et al. Study on bending fretting fatigue damages of 7075 aluminum alloy[J]. Tribology International, 2013, 59, 38- 46.
doi: 10.1016/j.triboint.2012.06.016
11
PENG J F , ZHU M H , CAI Z B , et al. On the damage mechanisms of bending fretting fatigue[J]. Tribology International, 2014, 76, 133- 141.
doi: 10.1016/j.triboint.2013.12.018
LIU D W , PENG J F , TIAN L . Study on bending fretting fatigue characteristics of 30CrNiMo8 alloy steel[J]. Materials for Mechanical Engineering, 2014, (8): 48- 52.
TIAN L , CHEN H , PENG J F . Study on bending fretting fatigue characteristics of 40CrNi2MoA alloy steel[J]. Lubrication Engineering, 2014, (6): 14- 18.
14
HYUKJAE L , SHANKAR M . Investigation into effects and interaction of various fretting fatigue variables under slip-controlled mode[J]. Tribology International, 2006, 39 (10): 1213- 1219.
doi: 10.1016/j.triboint.2006.02.011