What are the advantages of large cast iron platforms?
The working surface hardness of large cast iron platforms is HB170–240. The inspection platform is designed, processed, and produced according to the "Cast Iron Platform" 200 standard, with an accuracy grade of 2. The flatness tolerance of the working surface is no greater than 0.064mm, and the surface roughness Ra is allowed to be 5μm. The thickness of the large cast iron platform surface is required to be 30mm, with a total platform height of 200mm. The thickness of the side walls, the thickness, height, and density of the bottom ribs are designed according to relevant standards and load requirements.
Temperature control and the use of auxiliary materials in sand casting for large cast iron platforms: Since hot sand has a significant impact on the entire sand casting process for large cast iron platforms, it is essential to avoid issues through proper methods. On one hand, temperature must be controlled, generally maintained at around 50 degrees Celsius. If the temperature is too high, it will reduce the casting of large cast iron platforms, but if it is too low, it will interfere with the normal progress of casting.
Steps for using furnace construction to cast large cast iron platforms: The main furnace construction tools include a Martin vibrator (pneumatic): working air pressure above 0.6MPa. Due to insufficient pressure in the compressed air system, a booster pump is currently used, which can achieve a pressure of 0.8MPa. Other tools include a six-tooth ramming fork, round ramming head, crescent-shaped ramming head, ramming tool connecting iron pipe, thermocouple, and multi-point temperature recorder.
The auxiliary support positions for the inspection and use of large cast iron platforms should be the same as those in the design drawings, ensuring a reasonable layout of the supports. During use, avoid violent collisions with the working surface of the large cast iron platform to prevent damage. The weight of the workpiece must not exceed the rated load of the riveting platform; otherwise, it may reduce work efficiency, damage the structure of the large cast iron platform, or even cause deformation, rendering it unusable.
Core making for large cast iron platforms: Sand cores that have not been coated with paint may have sand grains that are too coarse or poorly distributed, which, like uneven distribution of raw sand grains, can affect mechanical sand adhesion. If the sand core is not compacted, similar to uncompacted sand molds, it can significantly impact mechanical sand adhesion. A rough or porous surface on the sand core can cause mechanical sand adhesion, as molten metal or metal oxides can infiltrate the core after wetting such surfaces. Sand cores absorbing moisture during storage can be problematic for large cast iron platforms, as excessive moisture is hard to detect. Some sand cores may appear dry but still have high moisture content.
Preparation before furnace construction for large cast iron platforms: Inspect and debug the mechanical system, hydraulic system, electrical system, and water cooling system of the medium-frequency induction furnace. Ensure the lining cold-state test is completed, set signal values, and eliminate potential unexpected faults during furnace operation. Mold preparation: Molds must be strictly inspected according to drawing requirements, with surfaces polished smooth and rust removed. Preparation for melting large cast iron platforms: Prepare melting blocks: 3–5t, small pieces of clean scrap steel, pig iron, and small pieces of clean recycled material.
Large cast iron platforms have accuracy grades of 0, 1, 2, and 3, and are made in ribbed or box-type structures with working surfaces that can be rectangular, square, or circular. The working surface of large cast iron platforms is processed using scraping technology and can be machined with V-shaped, T-shaped, U-shaped grooves, and round holes. On the other hand, auxiliary materials can be used and controlled to avoid unnecessary issues that may affect the overall sand casting effect. Additionally, the addition of new sand for large cast iron platforms must be carefully managed to maximize its effectiveness.
Weiyue Machinery, Ms. Xie 15350773479