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Comprehensive Analysis of Cast Iron Platform Production Process: Unveiling 5 Core Technologies from Casting to Scraping
In the fields of large-scale equipment installation, measurement, and mechanical processing, cast iron platforms are indispensable foundational tooling. Their flatness accuracy directly affects the stability of equipment installation and the reliability of measurement data, while high-quality cast iron platforms require refinement through multiple processes. This article delves into 6 core technologies from casting to scraping, revealing the production secrets of cast iron platforms. 1. Material Ratio and Smelting Technology
The performance of cast iron platforms begins with the material, with gray cast iron HT250-300 being the mainstream choice. Its carbon content needs to be controlled between 2.9%-3.5%, and silicon content between 1.8%-2.4%, achieving a balance of strength and good wear resistance through reasonable ratios. During smelting, a medium-frequency induction furnace is used, with pig iron, scrap steel, and carburizing agents added in proportion. The temperature is raised to 1450-1500°C, and ferrosilicon and ferromanganese are added for deoxidation treatment. The key lies in controlling sulfur and phosphorus content (sulfur ≤0.12%, phosphorus ≤0.3%) to avoid hot cracking or cold brittleness in the castings. After smelting, the molten iron must be left to stand for more than 30 minutes to ensure purity, laying the foundation for subsequent casting.

2. Sand Casting and Pouring Process
The quality of the sand mold directly determines the accuracy of the casting. Resin sand molding technology is employed, with sand grain size controlled between 50-100 mesh, resin addition at 2.5%-3%, and curing agent at 1%-1.5%, ensuring the sand mold strength reaches above 8MPa. During molding, CNC sand molding machines are used, with mold cavity size errors controlled within ±2mm and surface roughness Ra ≤12.5μm. The pouring stage adopts a stepped gate design, with molten iron pouring temperature maintained at 1380-1420°C and pouring speed controlled at 5-8kg/s. A slow-fast-slow rhythm is used to avoid slag entrapment and porosity. For large platforms (≥2000×3000mm), segmented pouring combined with aging treatment is required to reduce internal stress.
3. Aging Treatment Technology
After the casting cools below 200°C, artificial aging treatment is necessary to eliminate casting internal stress. The casting is placed in an aging furnace, heated to 550-600°C at a rate of 50°C/h, held for 4-6 hours, and then cooled to below 200°C at a rate of 30°C/h before removal. For high-precision platforms, secondary aging is also required, where after rough machining, the temperature is raised again to 400-450°C and held for 3 hours to further stabilize the metallurgical structure. Aging treatment can reduce residual stress in the casting by 60%-80%, preventing deformation during subsequent processing.
4. Rough Machining and Stress Relief
Rough machining uses large gantry milling machines to remove 2-5mm of the oxide layer and defective surface from the casting. The machining sequence follows the principle of "surface first, holes second; rough first, finish second," first milling the upper and lower surfaces to ensure parallelism error ≤0.1mm/m, then processing T-slots, positioning holes, and other structures. After rough machining, natural aging for 2-3 weeks is required to further release stress through environmental temperature changes. For extra-large platforms (≥5000×8000mm), vibration aging technology can be used, vibrating at 10-50Hz for 20-30 minutes to accelerate stress relief.
5. Finish Machining and Surface Grinding
The finish machining stage uses high-precision surface grinders, with grinding wheel grit selected between 80-120 mesh and grinding speed at 30-35m/s. A method of "multiple passes, gradually reducing feed rate" is adopted, with a feed rate of 0.05-0.1mm and a final feed rate ≤0.01mm, ensuring flatness error ≤0.05mm/m. During grinding, sufficient cooling fluid must be used to prevent thermal deformation of the workpiece, while an online measurement system monitors flatness accuracy in real time to adjust grinding parameters promptly. For spliced platforms, the height difference between splicing blocks must be ≤0.03mm.
From material smelting to manual scraping, the production process of cast iron platforms is a combination of technology and experience. Each core technology directly affects accuracy, and strict process control is key to ensuring platform performance. Only by mastering these technical points can high-precision cast iron platforms that meet the installation needs of large-scale equipment be produced, providing a solid foundation for industrial production.
Weiyue Machinery Ms. Xie 15350773479