The danger of wet charge in the foundry is a serious safety hazard. When the molten metal comes into contact with any water, moisture or liquid-containing material, the water immediately turns into steam, expands to its original volume by 1600 times, and produces a strong explosion. There is no sign of this happening. It throws molten metal and possibly high-temperature solids out of the medium-frequency electric furnace, putting workers, themselves and their nearby plants and equipment at risk. Water/metal explosions can occur in any furnace. However, it has a more serious side effect on the intermediate frequency electric furnace, including the possibility of a combined explosion - this is caused by the contact of the liquid in the damaged cooling system with the molten metal in the molten pool. The occurrence of water/metal explosions does not necessarily require the presence of molten metal. If a sealed barrel or container filled with water is added to an empty but very hot intermediate frequency electric furnace, an explosion will occur. In this case, the explosive force will eject the newly loaded charge, which may damage the refractory lining.
The danger of sealing containers
The dangers that are easily overlooked are the containers that appear to have been sealed and the sections that are cut off at both ends. Obviously, containers containing flammable liquids or their fumes will explode as early as the fragments themselves melt. Preheating the sealant does not prevent this hazard from occurring. In fact, the sealed container is
This danger of explosions in the preheating system is present. The vigilance of the operator is its only precaution. The sealant should never be allowed to enter the intermediate frequency furnace or preheater. The cut-off section of the waste pipe and the apparently empty sealed container do not appear to be dangerous, but in reality they are equally dangerous. Even if they are not filled with a flammable liquid, the air contained therein will rapidly expand when it encounters heat. In extreme cases, the pressure builds up enough to swell the container wall or escape from the closed closed tube end. If this happens, the strongly discharged gas will push the hot debris.
Pressing out the intermediate frequency electric furnace or crushing it into a furnace lining will cause damage.
Other danger
Cold or cold tools and cold, fragile materials pose special hazards to their operators because they may contain a thin layer of surface moisture or absorbed moisture. If it comes into contact with the molten pool, the water vapor will turn into steam, causing it to spray or splash. Wearing appropriate protective clothing and face and eye protection usually protects the operator. Preheating cold materials and tools can prevent many splash damage. In the ferrous metal foundry, the greatest risk of splashing occurs near the last moment of smelting, when the foundry adds ferroalloy to the melt or inserts the tool into the melt. These ferroalloy materials may have absorbed moisture from the surrounding environment. A thin layer of moisture is also condensed on the sampling spoon and the slag. The manufacturer's instructions for storing alloy materials and preheating tools should be followed to minimize water vapor build-up and reduce the risk of splashing. In the non-ferrous metal foundry, when the ingot is added to the molten metal, spray or splash occurs due to the contact of the surface condensate with the molten metal. Ideally, the ingot should only be placed in an empty furnace or placed on top of a solid return charge. Added to the molten pool
The ingot should be preheated or added using a remote feeding system. Since it is impossible to force the outdoor air to be completely free of moisture, there is always the possibility of water condensation and splashing. Water vapor condensation and absorption in two smelting
The ease increases with time. Therefore, the maximum splash hazard is likely to occur at the beginning of the work week or workday, or after the intermediate frequency furnace has stopped working for maintenance. During these start-up phases, the initial smelting should be carried out for more time, which helps to reduce the potential for splashing hazards. Centrifugal casting waste rolls When a centrifugal casting waste roll is added to an intermediate frequency electric furnace, special measures are required. Ideally, such waste should not be melted in an intermediate frequency furnace. The danger lies in the possibility that the scrap roll may contain a tough inner core overlaid with a fragile outer layer. Different expansion rates can cause the surface material to be explosively separated from the coil material, damaging the equipment and injuring people. If the waste roll is meltable, the waste roll is broken and broken before feeding, thereby minimizing the risk of breaking into pieces.