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　　Let me explain to you about... Medium-frequency furnace Precautions for Steelmaking

　　How does medium-frequency furnace steelmaking work?

　　Medium-frequency furnace steelmaking is a technology that uses eddy currents induced by medium-frequency magnetic fields to melt scrap steel, which is then processed into steel products via continuous casting and continuous rolling mills. The products produced by this method are no longer the “strip steel” of the past. According to surveys conducted by relevant institutions, China currently has approximately 70 medium-frequency furnace steel plants with a combined production capacity of around 100 million tons. However, actual output fluctuates considerably. In early February of this year, due to sluggish demand in the construction steel market and a decline in imported iron ore prices, the cost of blast furnace-converter steelmaking processes decreased. Medium-frequency furnace Steel mills lost their competitiveness and almost all of them ceased production. However, in July, as demand for construction steel increased and iron ore prices rose, output at medium-frequency furnace steel plants surged rapidly, reaching an annual steel production capacity of 500 tons.

　　Compared with converter and electric furnace steelmaking, the key difference with medium-frequency induction furnaces is that they cannot inject oxygen to form slag. Consequently, harmful elements such as phosphorus and sulfur cannot be removed from the molten steel—especially, the phosphorus content cannot be reduced. As a result, the resulting steel is prone to brittle fracture and can only meet “strength” requirements but not “toughness” requirements. Such steel can only be used for applications like filling cement blocks, road concrete barriers, vegetable greenhouse frames, and other similar purposes, thus having a limited scope of application and being unsuitable for widespread use in the construction industry.

　　Precautions for Steelmaking in Medium-Frequency Furnaces

　　Guided by the spirit of comprehensively deepening reform, the government is eliminating [obstacles] through administrative measures in accordance with the law. Medium-frequency furnace The production capacity of steelmaking should primarily be reflected in the standardized handling of environmental protection, energy consumption, and product quality. Here, the author briefly analyzes the feasibility of these aspects:

　　First, in terms of environmental protection, since medium-frequency furnaces for steelmaking do not blow oxygen or form slag and emit less smoke and pollutants than converters and electric furnaces, their environmental impact is relatively lighter. Therefore, whether or not they meet environmental protection standards should not be the primary basis for eliminating medium-frequency furnace steelmaking production capacity.

　　II. In terms of energy consumption, we compare the consumption indicators for key production stages, expressed as energy consumption per ton of steel (in kilograms of standard coal per ton of steel). For medium-frequency furnace steelmaking, the electricity consumption per ton of steel ranges from 600 to 700 kilowatt-hours. Considering energy conversion—where 1 kilowatt-hour of electricity is equivalent to 0.404 kilograms of standard coal—the corresponding energy consumption amounts to between 242 and 282 kilograms of standard coal per ton of steel. Steelmaking enterprises using electric furnaces, taking into account factors such as steel quality, typically require 700 to 800 kilograms of relatively pure hot pig iron per ton of steel. As a result, the electricity consumption per ton of steel drops from around 500 kilowatt-hours to between 150 and 200 kilowatt-hours. Converted into coal, this represents approximately 60 kilograms. However, since molten iron serves as the carrier material, and given that the energy consumption of iron itself is 460 kilograms of standard coal per ton, adding 700 to 800 kilograms of molten iron per ton of steel effectively translates into an energy consumption of 322 to 368 kilograms of standard coal. Adding these two components together yields a total energy consumption ranging from 382 to 448 kilograms of standard coal per ton of steel. Therefore, energy consumption should not be used as the primary basis for eliminating medium-frequency furnace production capacity.

　　Third, in terms of quality, most construction steel in China enters the construction sector via distribution channels. The supply and demand for steel are governed by national standards, which cover a wide range of applications and include low-grade and low-quality steels with relatively low requirements for steel quality and performance—particularly regarding phosphorus and sulfur content, whose upper limits are both set at 0.045%. Moreover, these standards set lower limits for elements such as manganese and silicon, which are beneficial for enhancing steel performance. According to current standards, alloying elements can even be omitted in construction steel products—a standard typically achievable by medium-frequency reactors. However, such steel exhibits poor toughness and is brittle, making it unsuitable for large-scale use in the construction sector. It is particularly well-suited for mid- and high-rise residential buildings and infrastructure projects. Therefore, it is essential to classify and refine quality standards for construction steel based on its specific intended use and impose strict limitations. Medium-frequency furnace The entry of steel into the construction sector provides an important regulatory basis for eliminating its production capacity.