滚抛磨块物理性能及其对7075铝合金滚磨光整加工的影响

The Effect of the Physical Properties of the Granular Media on the Finishing of 7075 Aluminum Alloy

目的探索不同材质滚抛磨块的物理性能,及其对7075铝合金滚磨光整加工效果的影响。方法相同条件下,使用不同材质滚抛磨块对7075铝合金试件进行滚磨光整加工实验和摩擦磨损实验,测试铝合金试件加工前后的粗糙度和材料去除量。采用扫描电子显微镜(SEM)和能谱仪(EDS),表征加工前后试件表面和磨痕形貌及元素成分的变化。结果加工初始表面粗糙度Ra为1.200μm的铝合金试件,棕刚玉磨块的加工效率最高,加工极限Ra最低为0.262μm,对试件的材料去除量最大,呈递增趋势。白陶瓷磨块加工后,试件表面光亮度最好,氧化铝加工次之,棕刚玉加工最差。氧化铝磨块加工后,试件表面出现Fe元素堆积,棕刚玉磨块加工后,试件表面存在凹坑缺陷,凹坑内C、O元素质量分数分别达到了20.85%和41.86%。结论加工初始表面较粗糙的铝合金试件,白陶瓷磨块加工效率及加工极限适中,加工后,试件表面无缺陷,表面光亮度最好。颗粒强度较小的滚抛磨块自锐性较好,加工效率高,但其表面致密性较差,磨耗大,不仅使得磨块利用率低,并且更易与试件表面发生吸附和氧化作用,在试件表面形成杂质颗粒和金属氧化物,降低试件表面光亮度。

This paper aims to explore the physical properties of different materials of roller polishing blocks and their influence on the finishing effect of 7075 aluminum alloy.Under the same conditions,the 7075 aluminum alloy specimens were sub-jected to barrel polishing and finishing experiments and friction and wear experiments with different materials of rolling abra-sive blocks to test the roughness value and metal removal amount of the aluminum alloy specimens before and after processing.Scanning electron microscope(SEM)and energy disperse spectroscopy(EDS)were used to characterize the changes of the surface and wear scar morphology and element composition of the specimen before and after processing.For aluminum alloy specimens with initial surface roughness Ra of 1.200μm,the brown fused alumina grinding block had the highest processing efficiency,the lowest processing limit Ra of 0.262μm,and the material removal of the specimens was the largest,showing an increasing trend.The surface brightness of the specimens processed by white ceramics was the best,followed by alumina,and brown corundum the worst.The surface of the aluminum oxide processed specimens showed accumulation of Fe elements.After the brown corundum abrasive block was processed,the surface pits and other defects of the specimens were more serious,with the content of C and O elements in the pits reaching 20.85%and 41.86%,respectively.For aluminum alloy specimens with rough initial surface,the processing efficiency and processing limit of white ceramic grinding block are moderate,and the surface of processed specimens has no defects and the surface brightness is the best.The rolling mill with small particle strength has better self-sharpness and high processing efficiency.However,due to its poor surface compactness and high abrasion,the grinding block not only has a low utilization rate,but also is more likely to adsorb and oxidize with the specimen surface,forming impurity particles and metal oxides on the surface of the specimen and reducing the surface brightness of the specimen.