The nominal tonnage of a converter, also known as its nominal capacity, is measured by the average tapping volume of the operating furnaces. For example, a 120-ton converter has an average tapping volume of 120 tons; a 300-ton converter has an average tapping volume of 300 tons. Using the average tapping volume to express nominal tonnage is not limited by the proportion of molten iron in the charge nor by the casting method. The corresponding charge volume can be calculated based on the converter’s tapping volume.

Taping volume = Charge volume / Metal consumption coefficient

Charge volume = Tapping volume × Metal consumption coefficient

The Metal consumption coefficient is the amount of steel consumed to blow one ton of steel. The Metal consumption coefficient varies depending on the raw materials and operating conditions.

Top-blown converters with a nominal tonnage of less than 100 tons are considered small converters, those with a nominal tonnage of 200 tons or more are considered large converters, and those between 100 and 200 tons are considered medium-sized converters. At present, the largest nominal tonnage of converters in my country is 300t.