On 2018-08-08 14:48:54
vacuum induction furnace smelting common problems
How to solve the common problems in vacuum induction furnace smelting?
Vacuum induction furnace is an important equipment of vacuum smelting. At present, it is mainly used for smelting precision alloy, alloy steel, electromagnetic materials and high temperature materials. There are two types of vacuum induction furnace: intermittent type and semi continuous type. The furnace with capacity less than 150 kg is usually intermittent type. Two types with capacity between 150 and 300 kg can be used, while the furnace with capacity more than 500 kg is semi continuous type.
When using the vacuum induction furnace for smelting, the staff often encounter various problems. Today, they sorted out some common problems, and also sorted out some methods to solve these problems, hoping to help consumers a little. Let's learn about the common problems of the vacuum induction furnace smelting.
1. Splashing in vacuum induction furnace
There are two main reasons for this problem in the smelting of vacuum induction furnace: one is that the melting speed is fast, the gas in the furnace charge is not fully discharged, or there is a problem of bridging in the melting process, the temperature of the molten metal at the lower part of the crucible is too high, and the large pieces of cold material suddenly fall into the molten pool, which will cause splashing; the other is the original Because the gas content is relatively high, the speed of adding is too fast, the temperature is too high, and the gas is melted into liquid before the full venting, which is also easy to cause splashing. So how to solve this problem?
Solution: one method is to select the appropriate power supply system from the beginning of raw material preparation and loading, operate carefully during melting to avoid the occurrence of bridging, and when adding alloy materials, first reduce the molten steel in the molten pool to the appropriate temperature, and then slowly add to avoid the occurrence of splashing. Another method is to cool down the temperature properly after splashing, slow down the reaction and make the boiling slowly weaken. In case of large splashing, argon can be introduced to reduce the vacuum degree and increase the pressure inside the furnace. After the boiling liquid steel is pressed to be calm, it can continue to be evacuated.
2. Problems of slag circle in vacuum induction furnace smelting
There are two reasons for this problem in smelting: when the crucible is smelting for a long time, the molten steel is continuously splashed during the evacuation process, thus forming a slag circle. Another reason is that the gas content in the liquid steel is relatively high, and the slag circle is formed rapidly when the liquid steel is evacuated.
Solution: there are three solutions. After the slag ring is generated, the slag ring is scalded by increasing the load and tilting back and forth during furnace cleaning. Second, for the slag circle which has been out of arc, it can be treated by feeding basket. Third, for the large slag ring, because the welding with the crucible is relatively firm, the vacuum breaking method can be adopted, and the fire welding or electric welding can be directly used for cleaning.
3. Bridge problem in vacuum induction furnace smelting
During smelting, the problem of bridging is mainly caused by the following reasons: the charge is too long; the steel containing carbon monoxide is added at the later stage of charging, and welded at the time of melting, resulting in bridging; the slag circle is too large, resulting in bridging.
Solution: there are three solutions: smash the bridge with a hammer; second, turn the crucible and burn the bridge with molten steel; third, break the vacuum for serious bridge.