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本文报导了从五个炉号的高锰钢失效辙叉中取样进行的小能量多冲试验结果。用电镜、金相法研究了断裂过程及断口形貌。用俄歇谱仪法测定了晶界磷的偏聚。在该试验条件下多冲寿命 N 断约为3×10~4次。裂纹萌生所需周次 N 萌约占N 断的55%。宏观裂纹扩展速率为0.2～0.42μ/每周。疲劳裂纹始于试样缺口端部,逐渐扩展,为明显的穿晶断裂。断口上有明显的疲劳条纹特征。条纹宽度约为0.5～1.7μ。在瞬断区为沿晶断口。冶金缺陷(疏松、缩孔、夹杂物等)和显微组织对裂纹扩展有相当影响。另外,还用铸态未经水韧处理的试样作了对比试验。
This paper reports the results of a small-energy multi-shot test taken from five high-manganese steel failure frogs with five heat numbers. The fracture process and fracture morphology were studied by electron microscope and metallography. The segregation of phosphorus in the grain boundaries was determined by Auger spectroscopy. Under this test condition, the multi-blanking life N break is about 3 × 10 ~ 4 times. Weeks required for initiation of cracks N sprouting accounted for about 55% of N broken. The macroscopic crack propagation rate is 0.2 ~ 0.42μ / per week. Fatigue cracks begin at the end of the notch, gradually expanding, as a distinct transgranular fracture. Fracture on the obvious fatigue characteristics. Stripe width of about 0.5 ~ 1.7μ. In the instantaneous area for the crystalline fracture. Metallurgical defects (porosity, shrinkage, inclusions, etc.) and microstructure have a considerable impact on crack propagation. In addition, the cast-in-place test was also used to compare the water-toughened samples.