Articles cast with molten iron are collectively referred to as iron castings. Due to the influence of many factors, there are often defects such as pores, pinholes, slag inclusions, cracks, pits and so on. The surface area carbon and wrinkle skin of iron castings are two forms of surface defects of iron castings. During the casting process, the solid and liquid phase products formed by gasification and decomposition of foam plastic models accumulate on the surface of the castings to form orange shaped carbon defects, and the surface wrinkling defects of the casting surface due to the poor temperature of the liquid metal filling. It is divided into 5 levels according to the severity of the area of 100 mm × 60 mm.Level 1: very slight wrinkle (fire); 2: slight wrinkle; 3: moderate wrinkle; 4: severe wrinkle; 5: serious severe wrinkle.