Abstract: The 8407 steel specimen with Al coating obtained by cold spray of Al powder was diffused at 550℃ for 4 h, then room temperature hard anodic oxidation was executed at 2.5 A/dm2 for 60 min for formation of Fe3O4×Al2O3 film on its surface. The melting-loss properties of specimens with aluminization and oxidation treatment and without treatment in liquid aluminum alloy of ADC12 at 620℃ under settlement and rotation conditions were evaluated by weight loss method. The microstructures of cross sections were observed by optical microscope after melting-loss test. The microstructure and local composition of Fe-Al interface structure of surface untreated specimen melting-loss tested were examined by SEM to explore the melting-loss mechanism of 8407 steel. Finally, the anti-melting-loss mechanism of oxide film was discussed. The results show that the formed Fe3O4×Al2O3 film can improve melting-loss resistance especially under the dynamic condition by reducing the wettability between steel and molten aluminum because it isolates steel substrate from liquid aluminum.

Key words: aluminization and oxidation treatment, oxide film, melting-loss, static melting-loss, dynamic melting-loss

摘要： 将表面经冷喷涂铝处理的8407钢样在550℃下扩散处理4 h，并在2.5 A/dm2电流密度下常温硬质阳极氧化处理60 min，使试样表面形成Fe3O4×Al2O3氧化膜. 采用失重法评价了静置和旋转条件下，表面渗铝氧化处理和未处理试样在620℃的ADC12铝液中的熔损性能. 利用光学显微镜观察熔损后试样横截面组织，利用SEM观察分析了表面未处理试样熔损后铁-铝界面组织和局部成分，探讨了8407钢的熔损机理及氧化膜抗熔损机理. 结果表明，8407模具钢经渗铝氧化处理后形成的氧化膜隔绝了钢基体与铝液的直接接触，降低了钢与熔融铝液间的润湿性能，提高了钢的静态和动态熔损抗力，且动态熔损抗力提高得更显著.

关键词: 渗铝氧化处理, 氧化膜, 热熔损, 静态熔损, 动态熔损