7A04-T6热挤压铝合金棒材阳极氧化表面色差成因分析  

Analysis of color difference on anodized surface of 7A04-T6 hot extruded aluminum alloy bar

作　　者：冉林果 Ran Linguo(Southwest Aluminum(Group)Co.,Ltd.,Chongqing 401326,China)

机构地区：[1]西南铝业(集团)有限责任公司,重庆401326

出　　处：《铝加工》2022年第5期14-17,共4页Aluminium Fabrication

摘　　要：7A04热挤压铝合金棒材在机械加工和硫酸阳极氧化后,制品表面出现黑条、黑斑等表面色差现象,严重影响制品外观质量。鉴于此,通过显微组织分析、维氏硬度检测、再次热处理后模拟阳极氧化等方法对表面色差成因进行了分析。结果表明:7A04棒材因固溶淬火时局部冷却强度不足,导致η析出相增多且分布不均,在硫酸阳极氧化过程中优先发生腐蚀从而形成较多ZnSO_(4)和Zn(OH)_(2)腐蚀产物,不能及时排出氧化膜孔,最终沉积在界面处,使铝合金制品表面宏观表现为黑色,存在黑条、黑斑等色差。After mechanical processing and sulfuric acid anodization of 7A04 hot extruded aluminum alloy bar, the color difference of the surface of the product appeared black strip and black spot, which seriously affected the appearance quality of the product. In this paper, the causes of surface color difference were analyzed by means of microstructure analysis, Vickers hardness test and simulated anodic oxidation after reheat treatment. The results showed that η precipitates increase and uneven distribution due to the lack of local cooling strength during solution quenching for 7A04 bar. In the process of sulfuric acid anodization, corrosion occurs preferentially to form more ZnSO_(4) and Zn(OH)_(2) corrosion products, which cannot be discharged from the oxide film pores in time, and finally deposited at the interface, which is macroscopic as the surface color difference phenomenon of aluminum alloy products.

关 键 词：热挤压棒材 固溶淬火 冷却速度 硫酸阳极氧化 色差 

分 类 号：TG376.8[金属学及工艺—金属压力加工] TG174.4