Defect characteristics and detection methods
The smooth and glossy dimples and pits on the surface of castings where chill is placed.
Causes of formation
- Interaction between water condensed on cold iron and alloy liquid
- The part of sand mold and core is not dried or re hygroscopic
- The mandrel placed is not treated or placed incorrectly
Prevention methods and remedial measures
- Design and place the cold iron accurately, and dry it before placing
- Thoroughly dry sand mold and core
- The aluminum alloy mandrel shall be designed and placed according to the shape and structure of the cylindrical part of the casting, and dried before placement
