Reasonable Selection Of Shell Material, And To Ensure Its Quality.

First, the selection of shell materials such as zirconium sand/quartz powder quality must meet the technical requirements, in particular of oxides in the surface layer of refractory materials must fall within the process, especially the content of iron oxides and other oxides cannot be exceeded, production of high Fe2O3 content will aggravate pitting.

Second, to test incoming raw materials, qualifying into the plant, warehouse. Inventory of raw material to regular re-inspection, substandard surface materials cannot be used.