Backyard steel furnaces were used by the people of China during the Great Leap Forward (1958-62). These small steel blast furnaces were constructed in the backyards of the communes, hence their names. People used every type of fuel they could to power these furnaces, from coal to the wood of coffins. Where iron ore was unavailable, they melted any steel objects they could get their hands on, including pots and pans, and even bicycles, to make steel girders, but these girders were useless, as the steel was impure and of poor quality and thus cracked easily. Unbeknownst to the Communist Party officials, the result was not steel, but high carbon pig iron, which needs to be decarburized to make steel.
The results varied from region to region. In regions where the steelmaking tradition had survived unbroken, where the old skills of the ironmasters had not been forgotten, the pig iron was indeed further refined into steel, and the steel production actually did increase. In regions that had no traditions of steelmaking, or the old ironmasters had been killed, or if there was no theoretical understanding of the blast furnace process and refining of the pig iron, the results were unsatisfactory. At worst, the fuel used was high-sulfur coal, rendering even the resulting pig iron useless needing to be re-smelted and desulfurized.
This was one of the major failures of the Great Leap Forward.
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