【摘要】 通过USF-2000超声波疲劳试验机研究了500 kg真空感应炉+电渣重熔冶炼的2000 MPa高强度钢（%:0.45C、2.0Si、0.9Cr、0.001S、0.005P、0.026Al、0.001 5O、0.002 8N）在共振频率20 kHz、载荷比R=-1,共振间隙150 ms时的超高周疲劳破坏行为。结果发现,疲劳裂纹大部分起源于钢中非金属夹杂物（夹杂平均尺寸12.3μm）,钢的疲劳强度和寿命随夹杂物增大而降低;内部夹杂物引起的疲劳破坏往往呈鱼眼型;随疲劳断口裂纹源夹杂物处应力场强度因子ΔK_inc的减小,钢的疲劳寿命N_f增加。更多还原

【Abstract】 The failure behavior of ultra-high cycle fatigue of a 2000 MPa grade high strength steel（0.45C,2.0Si, 0.9Cr,0.001S,0.005P,0.026Al,0.001 50,0.002 8N）melted by 500 kg vacuum induction furnace+electro-slag remelting has been studied by USF-2000 ultrasonic fatigue test machine with resonant frequency 20 kHz,load ratio R= -1,resonant gap 150 ms.Results found that the fatigue crack originated mostly from non-metallic inclusions（inclusion average size 12.3μm）;with increasing inclusion size beth fatigue strength and fatigue life of steel decreased;fatigue fail- ure area caused by inner inclusion presented fish-eye shape;and with decreasing the stress intensity factor rangeΔK_inc at fatigue crack originated site of inclusion,the fatigue life N_f of steel increased.更多还原