The Production Process of Tundish Impact Pot

The overall process of producing the intermediate drum current stabilizer is shown in the figure below:

1. Material Requisition

(1) Requisition a portion of the total required quantity. After product production, accurately weigh the materials used and precisely calculate the total material requirement before accurately requisitioning the production material quantity. Requisitioning should be done in smaller quantities to avoid surplus materials.

(2) All materials should be requisitioned in batches from front to back, following the first-in, first-out (FIFO) principle.

(3) All powders, additives, and finished products must be sealed and placed on wooden pallets. Any clumping must be immediately reported to the technical department; unauthorized use is strictly prohibited.

After requisitioning, crushing must commence. Crushing can only begin after quality control personnel confirm the moisture content of the raw materials is within acceptable limits. If the moisture content exceeds the limit, pre-drying or drying before crushing is required to ensure the quality of the raw materials. Regulations stipulate: moisture content of aggregates used for mixing <0.5%; moisture content of all magnesia <0.3%; moisture content of powdered raw materials <1.0%.

(3) Crushing can only begin after the moisture content of the raw materials meets the specified requirements. 

2.  Crushing

(1) When adding material to the jaw crusher, it is essential to maintain uniformity.

(2) After production begins, quality inspectors should take samples at the crushing site for particle size and moisture content analysis. If the samples are found to be substandard, the production team should be notified immediately to stop production, and the workshop should be consulted to identify the cause. When resuming normal production, the substandard material that has been crushed must be reworked.

(3) When changing materials during crushing, the entire production line, material pit, and work area must be thoroughly cleaned. If the cleaned material is free of contaminants, it should be re-crushed and screened the next time the same material is crushed.

(4) The crushed magnesia must be packaged with an inner lining, double-sealed, and labeled with its name, batch number, and specifications. Other materials may be packaged without an inner lining. Additionally, the usage method should be labeled according to the moisture content of the particles, such as mixed loading or grinding.

3. Grinding

(1) The grinding mill must be operated by designated personnel in the workshop.

(2) The grinding site must be thoroughly cleaned to ensure no foreign matter is mixed in.

(3) The particles fed into the mill must meet the following specifications: magnesia < 50mm, others ≤ 10mm.

(4) After production begins, quality inspectors will take samples on-site for particle size analysis to check for compliance.

(5) When changing materials during grinding, the mill should be cleaned and the grinding media removed 30 minutes after the mill stops feeding. The material storage area and receiving port should also be cleaned.

(6) For magnesia-type raw materials, if grinding is done in the following order, any subsequent material can be added directly to the mill after the first one is finished. Otherwise, the mill must be cleaned. 98.5 large crystals → 98 large crystals → fused 98 → fused 97 → 97 high purity → medium-grade magnesia → sintered magnesia.

4. Mold Installation

(1) The mold to be installed must match the drawings.
(2) When installing the mold, all debris such as slag must be cleaned. The installed mold must have tight gaps and all fixing bolts must be securely fastened.

(4) Apply grease evenly to the inner surface of the mold, ensuring the grease does not clump together. (5) After the mold is installed, it must be inspected by the quality inspector.

Only after passing the inspection and attaching a qualified label can the process proceed.

5. Mixing

The mixer scraper must meet the requirements in the table below.

(2) Detect the flow value in 30 seconds, and control the flow value between 200 and 230 mm.

(3) Pour material in sequence: large particles first, then small particles; aggregates first, then powders.

(4) The dry mixing time for the finished material should not be less than 1 minute, and the mixing time with water should be approximately 7 minutes.

(4) When discharging material, try to eliminate the "mountain" phenomenon as much as possible to reduce particle segregation.

(5) Mixing time: 6-7 minutes for castable material. General principle: the mixing time should tend to the upper limit within the mixing time range as the critical particle size decreases, ensuring that all components in the material are mixed evenly.

(6) During the mixing process, tests should also be conducted. Generally, every 6-10 batches constitute a comprehensive sample, which is taken from the workshop and sent to the material testing laboratory for testing. Specifically, the amount of water added, the flow value at the outlet, the flow value at 30 minutes, and the initial setting time are all tested. Production can only continue after the material passes the test.

6. Molding

Due to the large volume of the product, a vibrating rod is selected as the vibration tool.

(2) Molding should be completed within 20 minutes from the time the material leaves the pot. (3) When adding material, only one more mold can be added besides the one currently vibrating; the material addition height for each vibrating rod molding process should not exceed 200mm.

(4) During vibration, ensure consistent results on the edges, corners, bottom, and core; leave no holes when the vibrating rod is pulled out; vibrate until the molding surface is fully coated with slurry and basically no particles are exposed.

(5) Smoothing: After vibration, smooth the surface to a flat surface, ensuring a smooth, non-rough, and seamless finish.

7. Curing and Demolding

(1) The curing temperature of the molded product should be controlled within the range of 45~55°C, and curing should last for at least 6 hours.

(2) The demolding time for general products should be based on meeting the demolding strength. During demolding, use a wrench to tap the product to check the sound and test its strength. If the demolding strength requirement is not met, the demolding time can be appropriately extended. Demolding should be performed by experienced and skilled operators.

(3) For all mold demolding, the demolding method should be determined according to the drawings to ensure that the product is not damaged during the demolding process. (4) After demolding, the product should be protected with cotton pads to prevent corners and edges from chipping.

(5) After demolding, the product should undergo a full inspection of its dimensions and appearance quality.

8. Drying

The drying curve is shown in the figure below.