How to solve the problem of permeability in Castings process
Type (core) surface loose core pressure is too high or too low; mold exhaust sluggish; mold as a large gap between the box and run sand; Castings poor mobility or poor ventilation. Choose a reasonable shot sand pressure, improve the exhaust system to prevent suffocation; the use of small deformation of the material for the core box; use of good liquidity and good permeability of the Castings.
Shelling mold design is unreasonable, the core box temperature is not uniform, so that low-temperature parts of the low strength and shelling; Castings low melting point, curing speed is slow, low heat intensity. Improve the mold structure, so that the temperature distribution uniform; use high melting point, curing speed, high thermal strength of the resin.
Castings stomatal core exhaust sluggish; resin sand gas volume or gas speed is not appropriate; sand core curing is not complete. Improve the exhaust system, improve the exhaust effect; use high concentration or thicker of the original sand; the use of low-gas film frosted process.
Core core core strength is low or loose; crust thickness thin. Improve the mold structure, so that the temperature distribution uniform; use high melting point, curing speed, high thermal strength of the resin; adjust the sand pressure; improve the exhaust system.
Castings clay sand sand sand content is low; core surface is not dense. Adjust the sand pressure, to improve the effect of the core box exhaust, so that the surface of the sand core is more dense; the use of high temperature Castings or zirconia Castingss.
Type core (core) deformation, fracture mold heat uneven, or the core wall thickness difference, resulting in cooling shrinkage inconsistency; the use of curing shrinkage of large resin; core fork deformation or sand core storage uneven; Castings high temperature performance; Pouring pressure is too large to improve the mold structure, so that the temperature distribution uniform; the use of molding tray storage sand core; the use of curing shrinkage of small resin; use of high temperature and low expansion Castings; improved pouring system (using pressureless).
Castings within the shrinkage of the resin in the Castings at high temperatures to produce heat, slow down the solidification rate of molten iron, resulting in shrinkage. Using chilled Castingss; placed in the shell core within the cold iron.
Castings surface bad phenolic resin at high temperatures generated by the light carbon floating in the molten iron surface, solidification of the Castings surface wrinkles. Add about 2% of iron oxide powder, the use of high thermal conductivity of the original sand; shell core surface brush paint; cast to add special accessories.