During the smelting process of the intermediate frequency electric furnace, a large amount of scum will be produced, which will float and condense on the surface of the molten iron. If this slag is not removed, the quality of the casting will be affected. At present, many foundry industries use a relatively traditional method for slag fishing operations – the slag fisher wears protective gear and stands at the furnace mouth at close range, using a long iron fork to pick slag out of the furnace. It is very unsafe to cause sparks and molten iron to splash around. The temperature of the molten iron in the furnace can reach more than 1,600 degrees Celsius, and the temperature around the furnace mouth can also reach several hundred degrees Celsius. Especially in summer, the temperature at the furnace mouth is higher and the working environment is very harsh. The desulfurization slag has strong adhesion, and the slag is very heavy when gathered together. Manually removing the slag is very labour-intensive, and it takes many times to remove the desulfurization slag. The work efficiency is very low; when removing the slag, a lot of molten iron will be adhered to, resulting in a large amount of waste of raw materials.
The traditional method of scooping out slag not only poses great personal safety risks, but is also very labour-intensive, very inefficient, and consumes a lot of molten iron. The new slag-removing method uses a slag-removing robot, which has been used in many domestic foundry companies and has received unanimous praise from users. This is also the general trend of the foundry industry’s forward development.
The main body of the medium frequency furnace slag scooping robot adopts a bottom rotating rocker arm structure:
1) The rotation of the rocker’s arm is controlled by a variable frequency motor and can rotate 360 degrees (speed is adjustable).
2) The expansion and contraction of the jib is controlled by an oil cylinder.
3) The gripper rotation is controlled by an oil cylinder and can rotate independently at 90 degrees.
4) The lifting and lowering of the gripper and the grabbing action of changing hands are controlled by oil cylinders;
The equipment base, columns, rocker arms, and telescopic arms are connected to the overall structure, which is safe and reliable. The two electric furnaces share an intelligent slag-scooping machine (one for two). The intelligent slag scooping machine is installed in the middle of the two electric furnace platforms. The slag scooping operators can operate the equipment console on-site or the remote sensing handle on-site. The method controls the slag-removing robot to perform slag-removing operations.
The main advantages of slag-removing robots
1) Easy to install, the original on-site equipment does not need to be modified, and it occupies a small area.
2) The layout is reasonable. The equipment adopts the bottom rotating rocker arm structure, the manipulator telescopic arm is fixed, and the gripper structure is designed to rotate independently.
3) Safe and reliable, it uses ester-type flame-retardant liquid as the power source, which is good in lubrication, flame-retardant, is stronger and more stable in grabbing.
4) Easy to operate, the equipment adopts manual and remote control dual operation modes, which is safer and more reliable than manual operation standing next to the stove.
5) Reliable performance, all equipment materials are designed and manufactured with high-temperature resistance, electrical components are from Siemens & Schneider; assembly parts are from reliable manufacturers in the world.
Application benefit analysis
1) The equipment is reasonably installed and arranged. The structure adopts a bottom rotating rocker arm structure, which increases the operational stability of the equipment, opens up the working space around the furnace, and reduces hidden dangers caused by stumbling. Workers only need to stay away from the high-temperature furnace mouth and use the remote control. Work to avoid various dangers caused by close work. All rotating parts are equipped with fixed guards, so safety is fully guaranteed.
2) Using this equipment to control long-distance slag removal by remote control avoids thermal radiation damage to the body caused by the high-temperature molten metal during the electric furnace smelting process and greatly reduces the labour intensity of operators. Only one person can operate independently to easily complete large-scale operations. Electric furnace slag fishing operation.
3) Since manual slag removal is a (high-risk, high-temperature, high-intensity) work, workers are now unwilling to engage in this work. With the use of intelligent slag removal machines, workers’ work is easier and the working environment is greatly improved.
2. Energy saving
Shorten the residence time of molten iron in the furnace caused by manual slag removal. Generally, the slag volume of a 12-ton electric furnace is more than 200 kilograms. Manual slag removal requires three to four people, and the labor intensity is high and the slag removal time is long. The manual labour generally requires 15 Minutes or more; with the slag-removing robot, only one worker can operate it through the remote control, and the slag can be cleaned basically in about three minutes. Each furnace can save more than ten minutes, reduce the residence time of molten iron in the furnace, and improve production efficiency, greatly reducing power consumption, and greatly reducing production costs.
3. Environmental protection
The entire set of equipment uses ester-type flame-retardant hydraulic fluid as the power source, which has good flame retardancy, safety and environmental protection.
① The technical quality requirements for operating positions are reduced. Each set (one for two electric furnaces) only requires one person, reducing the number of operating workers.
② This equipment can be used to directly retrieve slag without adding a slag agglomerating agent, and the slag agglomerating agent can be saved by more than 60%.
The mechanical gripper is designed with a special process. During the slag fishing process, the action of pouring and squeezing molten iron is added, which effectively reduces the molten iron being brought out with the slag, and greatly reduces the waste of molten iron and the amount of waste slag transferred.
④ Due to the shortened slag fishing time, the number of smelting furnaces in a single shift is increased, which not only saves a lot of electricity but also improves efficiency.
The use of this equipment can reduce the damage to the furnace lining caused by manual lifting of slag, reduce the cost of later furnace mouth repairs, and greatly extend the service life of the furnace.
⑥The investment in this equipment can recover the cost in the short term, and the one-time investment will benefit in the long term.