镁钙处理对车轮钢中夹杂物及疲劳性能的影响

Effect of Mg and Ca treatment on inclusion and fatigue properties of wheel steel

在250 t钢包内对某车轮钢分别进行了镁、钙处理,探讨了夹杂物特征对钢疲劳寿命的影响,得出如下结论:镁处理、钙处理钢中T.O含量变化不大,均在0.0025%以下,但镁处理钢氮含量比钙处理钢普遍要低;钙处理精炼结束后钢中典型夹杂物主要为铝酸钙和(Ca,Mn)S,而镁处理钢中主要为尖晶石—铝酸钙复合夹杂物、尖晶石—硫化钙包裹型复合夹杂物,夹杂物尺寸较钙处理明显减小;当外部应力大于470 MPa后,镁处理钢的疲劳寿命几乎都大于钙处理钢,由此证明镁处理对改善钢的疲劳寿命有一定的贡献。

Mg and Ca treatment experiments were done in 250 t ladle for wheel steel,anu me effects of inclusions on fatigue properties were discussed. The results show that the total oxygen content both in Mg and Ca-treated steels was less than 0. 0025%, but the N content in Mg-treated steels was lower than that of Ca-treated steels; the inclusions are calcium aluminate and （Ca, Mn）S in Ca-treated steels ,and are spinel-calcium aluminate, spinel-CaS in Mg-treated steels, also the size of inclusions in Mg-treated steels are more fine. when the stress exceeds 470 MPa, the fatigue life of Mg -treated steels was more than ihat of Ca-treated steels,which has proved that Mg treatment was contributed to improve the fatigue properties of steel.