Pores, also known as air holes, are one of the common defects encountered in casting production. They typically appear inside, on the surface, or near the surface of castings, forming circular, elongated, or irregular shapes of varying sizes. Some pores occur individually, while others cluster together in patches. The pore walls are smooth and often exhibit a white color, sometimes even covered with a layer of oxide scale. Through long-term practice, we’ve categorized these defects—based on their distinct shapes and formation mechanisms—into types such as gas porosity, bubbles, pinholes, gas looseness, and gas shrinkage cavities.