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The energy consumption for melting iron water accounts for a significant portion of the cost of casting production, making the reduction of such energy consumption an important measure for foundries to cut costs and improve efficiency. I believe we can start from the following aspects:

(1) Designed by Weifang Kanda Electric Furnace Series Intermediate-Frequency Furnace The medium-frequency furnace, with its superior characteristics such as high melting rate, good power factor, and energy efficiency, outperforms parallel-circuit designs. Therefore, when selecting an induction furnace, it is advisable to opt for a series-circuit design. Moreover, a “one-to-two” (or “one-to-three”) configuration can be adopted to enhance transformer utilization and facilitate production organization. (2) The heat losses during the melting process in a medium-frequency furnace consist of three components: heat transfer through the furnace body, thermal radiation from the furnace top, and heat carried away by the cooling water. The heat generated by the resistance of the induction coil itself—accounting for approximately 20-30% of the furnace’s rated power—and the continuous heat transfer from the molten metal to the induction coil are both dissipated by the cooling water. For every 10°C reduction in operating temperature, the resistance of the induction coil decreases by about 4%, resulting in a 4% reduction in the coil’s power consumption. Hence, controlling the operating temperature of the induction coil (i.e., the temperature of the cooling circulating water) is critically important. The optimal operating temperature should be below 65°C, with a water flow velocity less than 4 m/s.

(3) Many foundries, when using small furnaces, remove the furnace lid and leave the furnace open to melt iron for convenience. This operating practice is highly incorrect, as it causes significant heat radiation from the furnace opening, thereby increasing energy consumption.

(4) It is crucial to reasonably determine the thickness of the electric furnace lining (refractory lining). Some foundries, in their single-minded pursuit of lining life and furnace longevity bonuses, have unilaterally increased the lining thickness without limit, thereby driving up energy consumption. In fact, while increasing the lining thickness does extend its service life, it also reduces the melting rate (lengthening the time required to melt the molten iron) and leads to greater continuous heat loss. At one domestic foundry, when using a 15-ton power-frequency furnace, the lining thickness was routinely increased from the prescribed 170 mm to 230 mm in an effort to prolong the lining’s lifespan. As a result, the lining’s service life did indeed improve significantly; however, the electricity consumption per ton of molten iron soared to as high as 1,500 kWh—a situation that simply wasn’t worth the cost. Later, the foundry had no choice but to reduce the lining thickness back to 170 mm, which nearly halved the electricity consumption.

(5) When used Circulating water When the water is untreated hard water, the carbonate and sulfate compounds of calcium and magnesium in the water accumulate and harden inside equipment and pipelines, forming scale that clogs the pipes. This leads to changes in the temperature, flow, and pressure of the circulating water, increases the resistance to water circulation, and consequently raises the operating power of the circulating water pump, resulting in higher energy consumption. Therefore, it is recommended to use closed-loop water-cooling equipment manufactured by Konda Electric Furnace for cooling purposes, thereby preventing scale formation in the equipment.

(6) Using a hydraulic crusher and a cleaning roller to crush and purify returned materials (branch-like gating systems and large scrap castings) into furnace charge pieces measuring 200–300 mm can increase the melting rate by approximately 20% and reduce power consumption by 5–10%.

(7) During the operation, care should be taken to prevent overheating of the molten metal and avoid using high-temperature holding for the molten iron. When not pouring, maintain the molten iron at a low temperature; just before pouring, raise its temperature back to a high level. This approach also helps reduce the loss of elements due to the high-temperature exposure of the molten iron.

(8) When starting to melt and solidify the charge, the amount added at each stage should reach approximately one-third to one-half of the furnace capacity; otherwise, power output will be affected and heat loss will occur.

(9) If the molten metal composition is not to be changed, avoid emptying the molten iron (leave about 15% residual molten iron at the bottom of the electric furnace). This way, after adding solid charge materials, the load variation during the initial stage of energization will be minimal, allowing higher power input from the start, thereby shortening the melting time of the metal charge and reducing energy consumption.