How should a purchaser choose a suitable cast iron ground rail?
During the pouring of cast iron ground rails, the metal liquid must not break flow, and the filling speed should not be too high. The pouring position and gating system should ensure that the metal liquid fills the mold cavity smoothly and facilitates the smooth discharge of gas. During casting, it is essential to ensure that the mold and core vents are clear. Vent channels should be created inside the sand core, and the core head gaps should be filled during the assembly of the cast iron ground rail to prevent metal liquid from entering and blocking the vent channels. The height of the sprue should be increased to enhance the static pressure of the metal liquid during filling.
Grade 1: The surface of the cast iron ground rail is smooth and free of cracks, or only has fine cracks, with no peeling between the coating and the base material., Grade 2: The surface of the cast iron ground rail has dendritic or網(wǎng)狀 fine cracks with a width of less than 0.5mm, and no peeling between the coating and the base material. Grade 3: The coating surface has dendritic or網(wǎng)狀 cracks with a width of less than 1mm, and the cracks are relatively deep. There are no貫通 coarse cracks in the橫向 or縱向 direction, and no peeling between the coating and the base material. Grade 4: The surface of the cast iron ground rail has dendritic or網(wǎng)狀 cracks with a width greater than 1mm, and貫通 cracks in the縱向 or橫向 direction. There is peeling between the coating and the base material.

To produce wax patterns with good surface quality and high dimensional accuracy for cast iron ground rails, the injection pressure must be strictly controlled. The injection pressure depends on the properties of the mold material, the injection temperature, and the structure of the wax pattern. When using a pneumatic wax injection machine to inject wax patterns, for paraffin-stearic acid wax materials, which have low viscosity and good fluidity, the commonly used injection pressure should be between 0.2 and 0.6 MPa. The temperature of the cast iron ground rail mold directly affects the surface quality of the wax pattern. When the injection pressure is set between 0.2 and 0.6 MPa, selecting an appropriate mold temperature is crucial for the quality. For paraffin-stearic acid wax materials, the commonly used mold temperature should be between 18 and 25°C.
Reduce the amount of resin and curing agent in the resin sand. Use low-nitrogen or nitrogen-free resins and raw sand with rounded particles, moderate particle size, low灼減量, and low micro-powder content to reduce the gas generation of the resin and improve the permeability of the cast iron ground rail resin sand. How to prevent porosity in cast iron ground rails: Use clean furnace charge, add覆蓋劑 on the surface of the metal liquid during the melting process, minimize the melting time, ensure thorough deoxidation and degassing of the metal liquid, allow the metal liquid to stand appropriately before pouring to facilitate gas escape, and prevent secondary oxidation of the metal liquid during the pouring process.
The accuracy of cast iron ground rails is classified as Grade 0, Grade 00, and Grade 000. Without installation and調(diào)試, these accuracies cannot be achieved. Therefore, cast iron ground rails are meaningless without installation and調(diào)試. Before adjustment and verification, the height of the three support points should be changed to roughly level the cast iron ground rail using a level, ensuring that the load is evenly distributed among the support points. The大理石板 platform points must be墊平穩(wěn) without破壞 the水平面. When verifying with a level, the cast iron ground rail itself serves as the measurement base and must be placed stably. When verifying with an autocollimator, the stability of the instrument and its支架 is particularly important. Therefore, when verifying such plates, the plate should be moved to a firm and stable site to avoid the impact of gravity changes on the measurement results of the cast iron ground rail.
Reasons for surface roughness of cast iron ground rails: During the production of cast iron ground rails, the preparation of paraffin-stearic acid paste wax膏 is divided into four steps: melting wax, shaving wax sheets, stirring wax膏, and aging. If the added wax sheets are too large or the stirring time is too short, the components of paraffin and stearic acid will mix unevenly, resulting in a rough surface of the wax pattern.
When preparing paraffin-stearic acid wax膏 for cast iron ground rails, it is generally recommended to melt the wax in a water bath melting tank, with the melting temperature controlled at around 90°C.
Weiyue Machinery, Ms. Xie, 15350773479