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As night fell, beneath the twinkling stars, Lin Feng entered Li Yutong's backyard, where he saw twenty neatly arranged square steel bars. He squatted down, picked up one of the bars, and examined it closely.
"Each square steel bar is two meters long with a cross-sectional area of about four square decimeters, and the weight of each bar is just around half a ton. Here we have ten tons of steel, that is, twenty square steel bars. It's uncertain how much refined iron can be extracted from a single bar."
The material Lin Feng used for making Flying Swords was refined iron, which could be considered the lowest grade material in artifact refining. However, even in ancient times, it likely required continuous smelting and purification within an iron mine to obtain a tiny amount of refined iron.
