Influence of iron contamination on the cutting force of A356-T6 alloys used in cylindrical turning

Abstract

A356 alloy is widely used in the automotive industry for applications such as cylinder heads, engine blocks and other components. Iron contamination is a major problem with this alloy. The use of recycled aluminum alloys has increased annually due to sustainable and energy issues involved in production. The presence of iron in Al–Si alloys enables formation of the β-Al5FeSi phase, which negatively affects mechanical properties and forming processes. In the present study, A356 alloy was cast with 0.2, 1 and 3% wt. of iron to reproduce a recycling process. Cooling rates of 1.17 and 1.81 °C/s were used. The material was submitted to thermal treatment by solubilization and artificial aging. The effects of iron contamination on cutting force during cylindrical turning were investigated using cutting speeds of 363 and 720 m/min, feed rates of 0.08 and 0.3 mm/rev and 1.5 mm depth of cut. In order to determine the influence of the parameters, ANOVA was performed at 5% significance. The results showed that cutting force increased by 185.8% at higher feed rates and declined 6.4% at greater cutting speeds. Greater presence of the β-Al5FeSi phase reduced cutting force by up to 5.6% when compared to the uncontaminated alloy, indicating that β-Al5FeSi formation can be beneficial when only cutting forces are analyzed, since its presence tends to minimize these forces. A slight change in the cooling rate affected the cutting force by 2.2%. Influences were also observed for combinations of two factors.