The black area is the casting part, which is divided into two parts: embedded box and casting.
The embedding process is very important for EPC. When burying the sand box, the bottom of the sand box shall be first added with the bottom sand with the thickness of 100mm, then the bottom sand shall be trowelled and vibrated into the model. If the bottom sand is too thin, it may burn the screen mesh in the air hole at the bottom of the sand box, and the uneven bottom sand will easily cause the deformation of the steel claw. After the model is put in, the sand is added twice for vibration compaction, and it can not be added to the riser once. After adding sand twice, cover the riser with plastic film, and then add a layer of top sand to protect the plastic film. Otherwise, if iron water splashes out during the, the plastic film will be burned, resulting in air leakage and pressure loss, resulting in box collapse. After the film is capped, an intersection ring is added at the riser to prevent sand from flowing into the casting.
The riser design size of the anode steel claw in huolingole site is 300 mm high and 260 mm in diameter. Compared with Heqing site, shrinkage cavity can be effectively prevented.
After the box is buried, push the sand box to the casting position of automatic butt joint, and make corresponding preparations before casting. For the separation tank and negative pressure pipe in the negative pressure system, water shall be added to automatically extend the interface to check whether the position is correct. Then open the negative pressure system. For the hollingoler site, one box and two pieces shall be cast separately, without internal sprue. Because the anode steel claw casting is large, if two steel claws are cast together, one of the risers of the two steel claws is an open riser and the other is a dark riser. The feeding effect of the named riser is obvious, the feeding effect of the dark riser is poor, and shrinkage porosity will occur. Separately casting can avoid this phenomenon.
During casting, the negative pressure should be kept above 0.5 pressure and between 0.5-0.8 pressure. One box of two pieces shall be poured in one minute, following the principle of slow, fast and slow casting, and the time shall not exceed one minute. In the process of casting, it is not allowed to break the flow, which is easy to cause box collapse.
After casting, close one of the two negative pressure pipes in the automatic butt joint system to maintain the pressure for 15-20 minutes. After pressure maintaining, remove the negative pressure and keep the casting warm for 2 hours. If the box is turned out too early, the casting will be softened as a whole, which will cause the casting deformation.
After two hours of pressure maintaining, the sand can be turned over and discharged into the sand treatment process. After being used, the sand can be cooled by water cooling and sand dropping, then it can be sieved and transported by screening conveyor and chain elevator into horizontal cooling for main cooling. After the sand temperature drops, the sand can be transported back to the sand storage hopper by pneumatic conveying to achieve the recycling of sand.
Utilization rate of molten iron 79%
Casting weight 385 kg
Riser weight 105 kg
Pouring temperature starting pouring temperature 1560
Pouring speed 25-30 seconds per piece
Burying speed 5-6 minutes per box