Hauv kev lag luam metallurgy, cov keeb kwm tsim khoom ntawm Silicon carbide crucible siv rau smelting non-ferrous hlau tuaj yeem taug qab mus rau xyoo 1930s. Nws cov txheej txheem nyuaj suav nrog cov khoom siv raw crushing, batching, tes spinning lossis yob txoj kev, ziab, tua, oiling thiab ya raws-pov thawj. Cov khoom ...
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