​Causes of pitting in precision castings

For a long time, pitting has been a major problem in the surface quality of precision castings. After precision castings of hardware tools are shot blasted and sandblasted, gray-black spots and pits will appear on the surface of the castings, resulting in waste of castings. A large amount of data shows that pitting is the accumulation of metal oxide inclusions in molten steel on the surface of castings. Below we will analyze step by step how to solve the pitting problem of precision castings.

1. Metal oxide inclusions brought in by poor deoxidation of molten steel.

2. The conditions for complete deoxidation are: use dry and clean charge, add ferromanganese after melting, add ferrosilicon for deoxidation, add silicon and calcium for deoxidation, let it stand for 2 minutes without power, add aluminum and finally deoxidize, then keep warm and pour. Immediately after pouring, add sawdust or waste wax, cover the box, seal and cool.