Drainage Manhole Cover 8001000 General Use for Vegetable Market Passage D400 Load Capacity 30 Tons Cengong Road Surface Cast Iron Rainwater Cover Plate

The spheroidization treatment of cast iron manhole covers is a key process to enhance their performance, mainly including the following critical steps:

1. Selecting the appropriate spheroidizing agent: Based on the composition of the cast iron and the performance requirements of the manhole cover, choose a suitable spheroidizing agent. Common ones include magnesium-based spheroidizing agents, etc. The addition amount must be controlled, generally between 0.8% - 1.5%.

2. Adding the spheroidizing agent via the pouring method or ladle transfer method: Use the pouring method to place the spheroidizing agent at the bottom of the ladle, cover it with a layer of iron chips, and then pour the molten iron in; use the ladle transfer method to add the spheroidizing agent into a specialized transfer ladle, then pour the molten iron into the transfer ladle, allowing the spheroidizing agent to mix and react with the molten iron inside the ladle.

3. Inoculation treatment: To further refine the graphite grains and improve the performance of the manhole cover, inoculation treatment should be carried out after the spheroidization process. Generally, methods such as metallographic analysis are used to ensure that the graphite spheroidization effect meets the requirements. Only well-spheroidized molten iron can be used to produce high-quality cast iron manhole covers.

4. Detecting impurities and harmful substances in the molten iron: Add certain impurities and harmful substances to the molten iron after spheroidization, and use methods like metallographic analysis for detection to ensure the composition of the molten iron meets design requirements, while also guaranteeing its safety and stability.