A new casting process for gray iron castings can reduce the production costs of enterprises

Gray cast iron refers to cast iron containing flake graphite. The fracture of gray iron castings is gray in the form of flake graphite. It has good castability, good vibration damping, good wear resistance, good machinability and low notch sensitivity. It is mainly used to manufacture racks and boxes. Gray iron castings are produced and formed by casting processes. At present, the existing gray iron casting casting process is complicated and cumbersome. Moreover, the tensile strength of cast gray iron castings is insufficient and easy to deform.

Based on this, a new casting process for gray iron castings can solve the problems of multiple process flows and complex processes in the existing casting process. Cast gray iron castings have excellent tensile strength and are not easy to deform after demolding. The gray iron casting casting process includes the following steps: furnace charge preparation: take new iron, recycled materials, carbon scrap steel, ferromanganese, ferromolybdenum, ferrosilicon and copper of predetermined specifications; first smelting materials: put new iron and recycled materials into the smelting furnace, and smelt the new iron and recycled materials in the smelting furnace; secondary smelting: after the new iron and recycled materials are all melted, add carbon chips, ferromanganese, ferromolybdenum, ferrosilicon and copper, carbon chips, ferromanganese, ferromolybdenum, ferrosilicon and copper into the smelting furnace in turn; prepare molten iron: continue to heat the smelting furnace, keep the temperature in the smelting furnace between 1300-1500, and prepare molten iron; prepare ladle: heat and dry the ladle, add inoculant to the bottom of the ladle; molten iron inoculation: quickly cast the molten iron into the ladle, stir to melt the inoculant, and cast it into the mold; cast gray cast iron: the ladle casts the molten iron into the mold cavity, and the molten iron solidifies and forms according to the mold cavity to make gray cast iron of predetermined specifications.

In an implementation example of a gray iron casting casting process, the smelting furnace is a GW-0.25 type medium frequency coreless induction furnace. In casting, the order of placing new iron and recycled materials in the smelting furnace is that large pieces are placed around the crucible wall of the smelting furnace and small pieces are placed at the bottom and center of the smelting furnace. When the temperature in the smelting furnace reaches 1420 to 1450, the grain size, color and width of the triangular sample fracture are observed to determine whether the amount of inoculated silicon is appropriately increased compared with that required by the gray cast iron composition table. In the process of preparing molten iron, an insulating covering agent is added to the smelting furnace. The insulating covering agent is an alkaline covering agent with a Cao-Sio2-MgO alkaline slag system. When the temperature in the smelting furnace reaches 1450 to 1480, the power supply of the smelting furnace is cut off, and the slag and insulating covering agent on the surface of the molten iron are quickly scraped off.

The gray iron casting casting process is simple, the raw material source is convenient, and the cast gray iron casting has excellent tensile strength and is not easy to deform, which can reduce the production cost of the enterprise.