Cast iron floor rail

Analysis of Market Demand Based on Cast Iron Ground Rail Quality
The molten alloy of cast iron ground rails is prone to gas absorption. Without refining, protection, and purification measures during the melting and pouring processes, the molten metal contains a large amount of gas, slag inclusions, and gas-entrapped types, leading to the formation of precipitated and reaction pores during solidification. Improper preparation of molding sand, cores, and coatings can cause interfacial reactions with the molten metal, resulting in surface pores and subcutaneous blowholes.
When melting cast iron ground rail molten iron in an electric furnace, the interval between each melt is about 50-60 minutes. Sometimes, the interval may be longer. The prolonged heat dissipation time of the cast iron ground rail pouring ladle leads to a lower temperature inside the ladle. Afterward, the temperature of the molten iron in the ladle drops by about 80°C. In winter, the temperature drop may be even greater. Therefore, when melting iron for ductile iron treatment in an electric furnace, the tapping temperature for cast iron ground rails should be higher than that of a cupola furnace.

In the production of cast iron ground rails, when the injection pressure is selected between 0.2 and 0.6 MPa, the injection wax temperature, especially when uniform, directly affects the surface roughness of the wax pattern. Before pressing the wax pattern, if the mold cavity of the cast iron ground rail die is not cleaned thoroughly, leaving residual cold water or dirt, the surface of the pressed wax pattern will be rough. During wax pattern pressing, if the temperature of the wax material or the die is too low, the fluidity and filling capacity of the cast iron ground rail wax material are reduced, making it difficult for the wax to quickly fill the mold cavity, resulting in a rough wax pattern surface.
If the pouring temperature of the cast iron ground rail is too low, the metal mold temperature is too low, the molten metal is not properly slagged, or the viscosity is too high, gases entrapped during pouring and filling, as well as gases precipitated from the molten metal, cannot be expelled from the mold or rise to the riser or vent. During humid seasons, when melting gas-absorbing alloys for cast iron ground rails, the alloy liquid absorbs a large amount of gas, causing batches of castings to be scrapped. Excessive resin and curing agent in the cast iron ground rail resin sand, high resin content, high angularity coefficient of the base sand and sand, excessively fine particle size, high loss on ignition, and high micro-powder content lead to excessive gas generation and low permeability of the sand.
The main element in cast iron ground rails, carbon, undergoes a process of loss and absorption during melting. As molten iron droplets fall onto hot coke, the cast iron ground rail absorbs carbon from the coke. Therefore, throughout the melting process, carbon absorption exceeds carbon loss, resulting in a net increase in final carbon content.
If the cores are not fully dried, the permeability of the cast iron ground rail is poor, ventilation is inadequate, moisture and gas-generating substances are excessive, the coating is not dried or contains too many gas-generating components, or chill cores and supports are rusty and not dried, and the metal mold has poor exhaust, invasive pores form in the castings. An unreasonable gating system for cast iron ground rails, overly fast pouring and filling speeds, and poor exhaust of the metal mold cause turbulence, vortexing, or flow interruption in the molten metal during pouring and filling, leading to the formation of entrapped pores in the cast iron ground rail.
When using aluminum for deoxidizing cast steel and cast iron, the residual aluminum content should be strictly controlled. For molten steel with a severe tendency to absorb gas, aluminum deoxidation should be avoided as much as possible. Methods such as purging with inert gas through porous plugs and powder injection can be used for external refining of the molten steel to remove gases and harmful impurities. For ductile iron, desulfurization should be strengthened, and under the premise of ensuring spheroidization, the amount of spheroidizing agent added to the cast iron ground rail should be minimized, the residual magnesium content should be reduced, and inoculation treatment should be enhanced.
Due to damp, rusty, or oily charge materials, humid climate, un-dried melting tools and pouring ladles for cast iron ground rails, improper composition of the molten metal, insufficient or lack of refining of the alloy liquid, a large amount of gas or gas-generating substances is present, leading to the formation of precipitated or reaction pores in the castings.