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用旋转弯曲疲劳试验机试验了不同稀土含量对几种结构钢疲劳性能的作用。用扫描电镜检验了疲劳源和疲劳裂纹的扩展,定量金相和金相鉴定研究了钢中夹杂物。试验表明,钢中含少量稀土(0.02％),RE/S=1时,夹杂物球化不完全,仍有少量条状夹杂物,但夹杂物总量最少,钢的过载疲劳寿命提高一倍以上,疲劳极限提高不明显。稀土含量增加,夹杂物完全球化,但夹杂物尺寸增大,数量增加,疲劳性能下降。稀土提高疲劳性能主要是由于净化作用,而不是由于变性作用。
The effect of different rare earth contents on the fatigue properties of several structural steels was tested with a rotating bending fatigue tester. Scanning electron microscopy (SEM) was used to examine the extension of fatigue source and fatigue crack. Quantitative metallographic and metallographic examination of inclusions in steel was performed. Experiments show that the steel contains a small amount of rare earth (0.02%), RE / S = 1, the inclusions incomplete ball, there are still a small amount of strip inclusions, but the least amount of inclusions, overload fatigue life of steel doubled Above, the fatigue limit is not obvious. The content of rare earth increases, inclusions are completely spheroidized, but the inclusion size increases, the number increases, the fatigue performance decreases. Rare earth to improve fatigue performance is mainly due to purification, not due to denaturation.