Defects associated with casting of pipes are often a main concern for the industry. In this chapter, a Taguchi analysis is carried out to understand the effect of three process parameter pouring temperature (°C), die spinning speed (rpm), and coolant flow time (mins) on the casting defect of pipes. The defect is defined in this work as the difference between the desired thickness of the pipe and the minimum actual (experimentally) achieved. A L9 orthogonal array is designed to carry out the experiments. Based on the S/N ratio analysis and ANOVA, it is seen that the die spinning speed plays the most critical role in defect of the pipes. As per the conducted experiments and Taguchi analysis, pouring temperature is seen to have the lest influence on the defects.
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Casting is a basic manufacturing process in which molten metal is poured into a mold cavity and allowed to cool for obtaining the desired shape. It is the oldest production process, which nowadays is also used to get parts of intricate shape and size. Any part having several tiny cavities and irregular shapes can also be produced using casting. Due to the handling of hot molten metal, the casting process should be performed with great precision and accuracy. The casting process is widely used to manufacture automotive engine parts, irregular shape machine components, pipes, etc. Many types of casting processes are there, which are based on different principle required to prepare part using a hot molten form. Sand casting, die casting, investment casting, centrifugal casting, gravity die casting, etc. are the different casting process used in industries. Sand casting is the oldest type of casting which is preferred for a solid part of complex geometry without any external force, whereas in die casting the molten metal is forced to get the shape of the part, investment casting is also called as lost-wax casting which is used to obtain smaller size parts with a high surface finish. To manufacture symmetric parts the centrifugal casting is used, in which the molten metal is rotated and the action of centrifugal force is utilized to obtain enhanced materials properties. Each type of casting has its application field and is considered for different part to be produced. Common parameters in all types of casting are molten metal temperature also known as pouring temperature, type of coolant, flow rate of coolant, time for coolant flow etc. The major issue with the casting processes is casting defects which occurs due to uneven cooling of molten metal and shrinkage of the material. The gating system is properly designed, risers are provided and various casting process settings such as preheating of mold are used to reduce the casting defects.
The centrifugal casting process is used to manufacture pipes with good mechanical and structural properties. Special purpose pipes such as lance pipes are also manufactured using centrifugal casting. The casting process is used for mass production of the parts. Important parameters of centrifugal casting are molten metal temperature, type, time and flow rate of coolant, the rotational speed of mold, etc. and output characteristics desired are material properties, surface finish, geometrical accuracy of surfaces, etc. Stirring of molten metal during centrifugal casting improves the materials and structural properties of the cast (Martinez, Garnier, & Durand, 1987). Researchers are interested in the study of the effect of the process parameters on the resulting production outcomes such as microstructure and mechanical characteristics of the cast (Wassilkowska, 2017). Yu at al. (Pivinskii, Litovskaya, Samarina, Volchek, & Kaplan, 1991) investigated the centrifugal casting of ceramics considering the velocity of casting, the temperature during casting, centrifugal pressure and reports that the control over the casting process parameters results in better surface, material and microstructural properties. Arbabi et al. (Arbabi & Ebrahimzadeh, 2010) analyzed the effect of the wall thickness of pipes manufactured by horizontal centrifugal casting process on resulting microstructural and mechanical properties with remarks that the wall thickness pipe significantly affects the output characteristics. Mohammad et al. (Rahimipour & Sobhani, 2013) evaluated the centrifugal casting process parameters of titanium composites using microstructural and phase characteristics of the cast, whereas Jien-Wei et al. (Yeh & Jong, 1994) water cooling integrated centrifugal casting of 7075 alloys considering rotation speed, pouring temperature, water flow, and grain refiner these parameters and materials microstructure and geometry as output responses. Abdul et al. (Ganai & Singh, 2020) studied microstructural, mechanical and geometrical parameter of the resulting cast of aluminium-6061 pipes manufactured by centrifugal casting experimentally and concluded that the mold rotational speed is the most significant parameter of the process & improper flow of molten metal varied the hardness of cast.