| High throughput continuous cast-rolling of process is directly forming 2mm-8mm billet by high throughput continuous cast-rolling mill and three hot rolling mills using electrolytic aluminum alloy liquid,the aluminum melt flow Up to 50 t / h.But the molten electrolytic aluminum alloys have high levels of inclusions.The inclusions will directly the properties of aluminum alloy plate,and also exacerbate the occurrence of clogging nozzle in the casting process of aluminum alloy production.The mechanical properties as an important indicator of product quality and the nozzle as a key component of high throughput continuous cast-casting mill to feed the molten aluminum,will affect the production efficiency of the process.Therefore,it is very important to study the variation for inclusions in molten aluminum alloy of high-throughput continuous cast-rolling process,and the effect of inclusions on high-throughput continuous cast-rolling process and product performance.The morphology,species and sizes distribution of inclusions in molten AA8011 and AA5052 aluminum alloys in the process of purification process were studied by means of the metallographic quantitative analysis,the PoDFA technique,the Prefil-Footprinter tests,scanning electron microscopy and energy spectrum analysis.The effects of high-alloying elements of AA5754 alloy on the inclusions in molten aluminum alloys were studied.The effect of inclusions on nozzle clogging of high throughput continuous casting and rolling A8011 aluminum alloy and on performance of Continuous Casting and Rolling AA5754 alloy plate were studied.At the same time,the practicality of IPP metallographic quantitative analysis method,Prefil-Footprinter tests and PoDFA technique on the practical industrial production were investigated.The types of inclusions in the molten high melt continuous cast-rolling aluminum are mainly oxide films,carbides,agent refiner(TiB2)and potential chloride/flux salts by the morphology analyzing.The high alloying element AA5754 aluminum alloy melt also contains magnesium oxide composed of magnesium oxide and MgAl2O4-spinel.The sizes of inclusions of molten AA5754 aluminum alloy are larger than inclusions of molten AA8011 aluminum alloy.However,with different continuous purification process,the inclusions are gradually reduced,and the shape of the inclusions from the reunion,prickly,irregular gradually become smooth shape,shape rules,evenly distributed.Before casting,the inclusions of the molten AA8011 aluminum alloy are mainly Al4C3 with dimensions less than 5μm,while the molten AA5754 aluminum alloy also contains some magnesium oxides with the sizes of 10 to 20μm.The evolution of the inclusions in molten AA8011 and AA5754 aluminum alloy in the continuous purification process was analyzed.The trend of the inclusions(inclusions area ratio)in the molten aluminum alloy gradually decreased,with the online purification process.However,the presence of alloying elements,especially Mg elements,will increase the contents and sizes of the inclusions in the melt.The inclusions content of the molten AA5754 aluminum alloy is 2 to 3 times that of the molten AA8011 aluminum alloy and 5~6 times in the size of inclusions of the corresponding location of High throughput continuous cast-rolling molten aluminum alloy.The addition of the Al-5Ti-B refiner increases the amount of inclusions in the molten aluminum alloy.The smaller inclusions can be removed by SNIF degassing,and the foamed ceramic filter has a good filtration effect on the larger inclusions for the two alloys.But the deep bed filter on the molten AA5754 aluminum alloy purification effect is not good as on the molten AA8011 aluminum alloy melt purification.Therefore,according to the different types of production alloys,adjust the use of deep bed filter in the industrial production process.Quantitative analysis of inclusions in molten AA8011 and AA5754 aluminum alloys was carried out by IPP metallographic quantitative analysis,Prefil-Footprinter tests and PoDFA method.The results of metallographic analysis,Prefil-Footprinter tests and PoDFA method were in good consistent.Because the inclusions of the molten AA8011 aluminum alloy are few,the use of PoDFA method is not significant,if necessary,can be used as a Prefil-Footprinter method validation.By studying the mechanism of nozzle clogging in the production of high throughput continuous cast-rolling AA8011 aluminum alloy,the clogged nozzle is composed of three layers: the reaction layer,slagged layer and metal layer.In the case of inclusions with dimensions less than 3μm have little effect on the performance of the alloy products,but it will aggravate the slagging of the castings,causing the nozzle to clog and reduce the production efficiency and increase the economic costs of the aluminum alloy products of high throughput continuous cast-rolling of process.At the same time due to the characteristics of high throughput continuous cast-rolling process,these smaller inclusions in the casting process are easy to gather together,resulting in cast plate segregation,affecting product performance.Through the tensile test and fracture analysis,the location of the inclusions,especially when the inclusions in the edge of the sample,is easy to form a crack source,resulting in alloy sheet fracture.With the increase of inclusions,high-throughput continuous casting rolling AA5754 Cast-rolling aluminum alloy tensile strength and elongation will be deterioration. |
