The article presents results of research on the influence of variable parameters of horizontal continuous casting on the structure of AlCu4MgSi (EN AW-2017A) alloy ingots. The special character of the process allows for a continuous change of some of its parameters, namely, of the casting speed and of the rate of the cooling fluid flow thorough the crystallizer. These parameters have a significant impact on the crystallization process of the liquid metal. Depending on the cooling rate, intensity of the convection inside the solidifying alloy, and its chemical composition, there may arise some differences in the structure of the cast. In this study, ingots obtained at different casting speeds have been analyzed. The research methodology, based on light microscopy and electron microscopy (SEM), as well as energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD), allowed for a thorough examination of the structure of the studied materials. The results were shown that an increase in the ingot casting speed leads to an increase in the average grain surface area.
The article presents the results of research concerning AlCu4MgSi alloy ingots produced using horizontal continuous casting process under variable conditions of casting speed and cooling liquid flow through the crystallizer. The mechanical properties and structure of the obtained ingots were correlated with the process parameters. On the basis of the obtained results, it has been shown that depending on the cooling rate and the intensity of convection during solidification, significant differences in the mechanical properties and structure and of the ingots can occur. The research has shown that, as the casting speed and the flow rate of the cooling liquid increase, the hardness of the test samples decreases, while their elongation increases, which is related to the increase of the average grain size. Also, the morphology of the intermetallic phases precipitations lattice, as well as the centerline porosity and dendrite expansion, significantly affect the tensile strength and fracture mechanism of the tested ingots.
The paper presents the research results of the influence of the precipitation hardening on hardness and microstructure of selected Al-Si and Al-Cu alloys obtained as 30 mm ingots in a horizontal continuous casting process. The ingots were heat treated in process of precipitation hardening i.e. supersaturation with subsequent accelerated or natural ageing. Moreover in the range of the study it has been carried out investigations of chemical constitution, microscopic metallographic with use of scanning electron microscope with EDS analysis system, and hardness measurements using the Brinell method. On basis of obtained results it has been concluded that the chemical constitution of the investigated alloys enables to classify them into Al alloys for the plastic deformation as EN AW-AlSi2Mn (alternatively cast alloy EN AC-AlSi2MgTi) and as EN AW-AlCu4MgSi (alternatively cast alloy EN AC-AlCu4MgTi) grades. Moreover in result of applied precipitation hardening has resulted in the precipitation from a supersaturated solid solution of dispersive particles of secondary phases rich in alloying element i.e. Si and Cu respectively. In consequence it has been obtained increase in hardness in case of AlSi2Mn alloy by approximately 30% and in case of AlCu4MgSi alloy by approximately 20% in comparison to the as-cast state of continuous ingots.