Surface water stain is a common, often overlooked quality defect in precision casting. It appears as white or gray watermarks, blotches, or damp residues on cast parts, ruining aesthetic appeal and leading to surface corrosion, poor coating adhesion, and shortened service life. These defects stem from raw material handling, process parameters, equipment performance, and environmental control.Yihui Casting shares industrial best practices to identify root causes, implement actionable fixes, and build a proactive pre···...