Quality inspection of investment casting parts is an essential part of the investment casting production process, whose aims are to ensure quality of investment casting parts in line with technical conditions of delivery acceptance.
1. Stomata: smooth hole exits in investment casting parts.
a Low calcinations' temperature and holding time is insufficient.
b Unreasonable gating system design, poor exhaust cavity.
c Metal liquid oxygen, in addition to gas is not sufficient.
2. Subcutaneous pores: Smooth holes appear after processing of investment casting parts
a Furnace is not clean or using too much materials of back furnace.
b Liquid metal oxide breathing in melting process, and oxygen is not sufficient.
c Reaction between surface and the metal liquid.
3. Pore residue: Coexistence of inclusions and holes
a Charging is not clean or re-charging too much.
b Oxygen is not sufficient melting process.
c Liquid steel contains more gas.
d Investment casting parts have insufficient calcinations.
4. Shrinkage and reduced depression: As holes caused by poor feeding, they have irregular shape and rough hole-wall on the investment casting parts.
a The structure of investment casting parts is irrational.
b Riser role feeding is poor.
c The temperature of pouring is too high.
5 Shrinkage: small scattered holes produce when slower cooling department on the investment casting parts.
a The structure of investment casting parts is irrational, difficult to fully shrink.
b Unreasonable riser design and poor shrinking on the role.
c Temperature when pouring is too low.
d The mold temperature is low, and cooling of investment casting parts is too fast.