1235铝合金冷轧板表面黑丝缺陷分析

Analysis on Surface Black Silk Defect in 1235 Cold-rolled Aluminum Alloy Plate

采用电解铝液直接铸轧生产厚度为7.0 mm,宽度为1 050 mm的1235铝合金铸轧板,经2道次冷轧成厚度为2.1 mm铝箔坯料。采用光学显微镜(OM)、扫描电子显微镜(SEM)及能谱仪(EDS)等对厚为2.1 mm冷轧板表面黑丝缺陷显微组织进行研究和分析,探讨黑丝缺陷形成的原因。结果表明,冷轧板表面黑丝缺陷局部存在不规则的凹坑,凹坑内存在粗大夹杂物及第二相颗粒,且退火冷轧板黑丝缺陷晶粒相对正常基体数量多且较小。能谱分析表明这些粗大夹杂物是富含Al和O元素组成的非金属氧化物Al_2O_3,第二相颗粒是由富含Fe、Al元素且含量较低的Si元素组成的金属间化合物Al Fe Si,因此造成冷轧板出现了黑丝缺陷。

1235 cast-rolled plates with 7 mm in thickness and 1 050 mm in width were manufactured with electrolytic aluminum liquid,then cold-rolled into a thickness of 2. 1 mm aluminum foil plates after2 times of cold rolling. Microstructure of surface black silk defects of cold-rolled plates with 2. 1 mm in thickness were studied by optical microscopy（ OM）,scanning electron microscope（ SEM） and energy dispersive spectroscopy（ EDS）,the formation causes of cold-rolled plates were discussed. The results show that there were some grooves in local surface black sill defect of cold-rolled plates,and coarse inclusions and second phase particles existed in the grooves,and the number of the grains in the surface black silk of annealed cold-rolled plates was much smaller than that of the normal matrix. Spectrum results declare these coarse inclusions were non-metal oxide Al2O3 rich in Al and O elements,and the second phase particles were intermetallic compounds which were composed of Fe and Al elements with low content of Si elements,those inclusions and precipitates were reasons that cause black silk defect.