Abstract: The mechanical properties and inclusions of hollow steel 55SiMnMo added 0.018% 120 nm Al₂O₃ nano- powder in earlier stage of reduction penod and 0.002% nano-powder during ingot casting have been studied. Results showed that with added 0.02% Al₂O₃ nano-powder the yield strength of forged and air-cooled steel 55SiMnMo increased by 13.9% and impact toughness at ambient temperature increased by 70.8%;by field emission SEM observation the most of Al₂O₃ nano-particle became non-spontaneous nucleus of non-metallic inclusions and the most inclusions in steel were fined by adding nano-powder,the size of inclusions was 300nm~3 μm.

Key words: Hollow Steel 55SiMnMo,Al2O, Nano-powder,Mechanical Properties,Non-Metallic Inclusion

摘要： 研究了中空钢55SiMnMo还原前期加0.018%、铸锭时加0.002%的120 nm Al₂O₃纳米粉后钢的力学性能和夹杂物。结果表明,添加0.02%Al₂O₃纳米粉使锻后空冷55SiMnMo钢的屈服强度提高了13.9%,常温冲击韧性提高了70.8%;场发射SEM观察得出Al₂O₃纳米颗粒大多数成为非金属夹杂物的核心,钢中大部分夹杂物得到了细化,尺寸均在300 nm～3μm之间。

关键词: 55SiMnMo中空钢, Al2O3纳米粉, 力学性能, 非金属夹杂物