Torsion fatigue characteristics and crackpropagation behavior of 15Cr14Co12Mo5Ni2 gear steel
LI Xin-yu1,2，YANG Mao-sheng2，ZHOU Xiao-long1，GUO Jun1,2
（1. College of Material Science and Engineering， Kunming University of Science and Technology， Kunming 650093， Yunnan， China 2. Institute for Special Steel， Central Iron and Steel Research Institute， Beijing 100081，China）
Abstract：The crack propagation behavior oftorsion fatigue fracture and the relationship between inclusions size and torsion fatigue lifeof 15Cr14Co12Mo5Ni2 steel were researchedthroughtorsion fatigue test. Torsional fatigue limit strength and[τ-N]cure was obtained， and the value of 15Cr14Co12Mo5Ni2 steel was 350 MPa，whosedispersion was large. Through observed fractures，the surface failure mode and subsurface failure mode as the main failure mode of the test steel， and the fracture mainly resulting from oxide inclusions were found. Thefracture mechanics conditions of fatigue crack propagation of 15Cr14Co12Mo5Ni2 steel were analyzed by calculating stress strength factor[ΔK] and crack propagation threshold value[ΔKth.] The load process of test steel in fracture was： type II load，type I load，type II load， and type I＋II load， which corresponded to crack sourcezone， fiber zone， fatigue crack propagation zone and instantaneous fracture zone. When the large crack formed， fiber zone would not appear， andthe load process was type II load， andtype I＋II load. The relationship between the size of the inclusions and the torsional fatigue life of the 15Cr14Co12Mo5Ni2 steel was obtained by eliciting formulas and fitting dates. It wasfound that[τ-N]cure of the test steel moved toward the high life zone， andwhen the size of inclusion in crack initiation was less than 5 μm， torsional fatigue life of 15Cr14Co12Mo5Ni2 steel would be more than 107 cycles with 350 MPa stress.
收稿日期: 2017-02-23
出版日期: 2017-09-07
引用本文:
李新宇，杨卯生，周晓龙，郭 军，. 15Cr14Co12Mo5Ni2齿轮钢的扭转疲劳特性及裂纹扩展行为[J]. 钢铁, 2017, 52(9): 84-91.
LI Xin-yu，，YANG Mao-sheng，ZHOU Xiao-long，GUO Jun，. Torsion fatigue characteristics and crackpropagation behavior of 15Cr14Co12Mo5Ni2 gear steel. Iron and Steel, 2017, 52(9): 84-91.
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