The gray cast iron properties and microstructure were analyzed in a foundry process under different cooling methods. The study tested four approaches: as-cast, furnace-cooled, air-cooled, and green sand-cooled. The results showed the variation of cementie Fe\({}_{3}\)C with 24.96, 11.64, 6.62, and 6.35 percent respectively, and the consequence is the differences in the hardness Rockwell scale of 95.8, 85.2, 94.7, and 97.0 HRB [7]. As the foundry process progresses, the crystal structure begins to re-form on cooling at the melting point, especially in solidifying when energy is given out in the form of the latent heat of fusion. Solidification depends on the rate at which heat can be removed. While the solidification is in a slow rate, the first nuclei increase in size as more eventually has transformed into large grains. Initially, the grain boundaries represented the points of growth outward from the nuclei. The number of clusters increases when cooling is rapid, and each cluster grows rapidly as a result. As more grains are formed in the solid, the metal is finer [8]. A constant temperature gradient is shown in Figure 1, which represents the solidification temperature increase as a function of the solidification rate for the Fe-4.28C eutectic composition. Possible solid constituents include g/graphite eutectic, g/cemente eutectic, and g/austenite dendrites. The dotted line indicates the phase with the highest interface growth temperature. The g/Graphite eutectic forms with a low solidification rate, followed by austenite dendrites, whereas the g/cemente eutectic forms with a high solidification rate [2]. Figure 1: Solidification rate for the Fe-4.28C eutectic composition [2]. Age strengthening is the final phase of the foundry process in gray cast iron, where the mechanical properties are defined. Tool wear and vibration are the principal issues during the machining process; the common solution had been stocking parts for a few days to reach metallurgical stability. A brake disk of gray cast iron was analyzed for hardness during aging, and the data collected showed that the metallurgical stability was reached at seven days. The investigations exhibited the importance of industrial conditions before machining the casting [9; 10]. An investigation has been conducted into the influence of age on the machining of a component of an automobile with a polycrystalline cubic boron nitride (PCBN) cutting tool. The test indicated that the tendency to improve the tool life is not under control during the first 100 h. After this time, there is a stable trend [11]. The age-strengthening effect in gray cast iron was analyzed, in terms of ultimate tensile strength, and the data collected showed a variation between 3.3% and 13% [12]. The age strengthening appears as nitride precipitation in ferrite. It appears that elements that interact with N, such as Mn, disturb the strength of the aging process, and the gray cast iron's machinability improves along with age-strengthening, particularly with free ferrite present [13]. Some foundry companies have established that five-day to room temperature aging provides a good balance between production and shipping and can require floor space [14]. A review of the literature found that the nature and temporal behavior of age strengthening are supported in two relevant aspects [13]. First, during the melting process, free nitrogen into iron-based alloys is required for the aging effect. Because this influence of the nitrogen could be related with the precipitate and diffusivity in the microstructure, which is validated to the fact that nitrogen is better diffused when the casting is cooling at room temperature [15]. In addition, the weight percent of iron-nitride (Fe\({}_{4}\)N) is linearly correlated with the changes of the ultimate tensile strength (UTS) from age strengthening, which implies that Fe\({}_{4}\)N significantly promotes the precipitate [16].