SAND CASTING EQUIPMENT.

1.he generation of pores will have an impact on the quality of casting

1.1 Destruction of metal continuity

1.2 Less carrying effective area

1.3 Stress concentration is easy to be caused near the pore, and the mechanical properties decline. Dispersion hole, air tightness decreased

2. Classification of stomata (by gas source)

2.1 Intrusion pores: the gas gathered on the surface of the sand material invades the metal liquid and forms Gas source: moisture in molding materials, adhesives, all kinds of add-onsFeatures: Most near the surface, large, oval or pear-shaped, the inner surface of the hole is oxidized.Formation process:Pouring -- water vapor (part from the parting surface, the vent, the other part of the surface gathered as a high pressure center point)-- pressure rise, dissolved into the metal -- part of the liquid metal escape from the sprue, the rest in the casting inside, the formation of the vent.Prevention: reduce the initiation amount of mold sand (core sand), increase the exhaust capacity of the casting mold.

2.2 Precipitation pores: the gas dissolved in the metal liquid precipitates due to the decrease of gas solubility in the condensation process, which causes the casting to form pores. Cause: metal melting and pouring in contact with gas (H2, O2, NO, CO, etc.)Characteristics: wide distribution, small pore size, affect air tightness.

2.3 Reaction pores: pores formed between metal liquid and casting material, core support, cold iron or slag due to the gas generated by chemical reaction. Such as: cold iron rust & NBSP; Fe3O4 + C -- Fe + Co ↑, forming pores near the chiller.
Prevention: the surface of chiller core support should not be corroded, greasy, dry.

3. Casting quality control
3.1 Reasonable selection of casting alloy and casting structure.
3.2 Reasonable formulation of casting technical requirements (allowable defects, with provisions)

3.3 Model quality inspection (model qualified -- casting qualified)

3.4 Casting quality inspection (macro, instrument)
3.5 Heat treatment of castings: eliminate stress, reduce hardness, improve machinability, ensure mechanical properties, annealing, normalizing, etc.

Xinyuanzhu Group specializes in the production of Ductile iron castings, Pig iron gray iron casting, Steel casting, Brass Casting, Malleable Iron Casting, and undertakes batch casting processing of castings. Welcome guests to cooperate with pictures or samples