How to distinguish casting sand holes, slag holes, air holes, loose holes, shrinkage holes
1: sand holes - holes caused by sand, irregular shape, rough surface of the hole, mostly located in the smaller cross-sectional position.
2: Dross hole - holes caused by impurities or liquids in the cavity into the cavity due to low melting point material, irregular shape, shallow depth, hole surface smooth and shiny, color, similar to enamel substances.
3: Stoma - Due to poor deoxidation of the liquid, the sand has a high moisture content and causes too much volatile matter to cause holes. Deoxidation is not good: the part and the whole part are wormholes, twists and turns, deep and round, similar to the round shape; sand has a high moisture content: (mainly steel castings) is easy to produce subcutaneous gas, shaped like a braid, depth 3-5mm; volatile Too much material: Mostly present in the middle of the slag hole.
4: shrinkage - due to too small riser, low temperature or irrational process, under the riser, the organization is loose.
5: shrinkage hole - severe shrinkage, irregular shape, from top to bottom, there is a big change, praised the triangle