Causes of Air Holes in High Chrome White Iron Air Ports

All carbon in white cast iron exists in the form of infiltrated carbon body (Fe3c), because the fracture is bright white. Therefore, it is called white cast iron. Due to the large amount of hard and brittle Fe3c, white cast iron has high hardness, high brittleness and is difficult to process. Therefore, it is rarely used directly in industrial applications, and is only used for a few parts that require wear resistance without impact, such as wire drawing dies, ball mill iron balls, etc. Mostly used as a billet for steelmaking and malleable cast iron.

The thin-section piston ring of single cast niobium-chromium alloy cast iron is prone to subcutaneous pores. The author's experiment shows that there is a corresponding critical value for the residual aluminum content in the original molten iron of the ring with a certain section, and the subcutaneous pores are prone to occur if the value exceeds this value. The author analyzes The effects of niobium content in cast iron, inoculant, and ferrosilicon on the porosity tendency are discussed. It is proposed to select a special niobium alloy with suitable melting point and specific gravity, and pay attention to the calculation of the residual aluminum content in the original molten iron during the inoculation and batching process. The rapid method of smelting molten iron and controlling the residual aluminum content in the molten iron below the critical value can effectively eliminate subcutaneous stomatal defects.