Semi GPC (SGPC) ya fito ne daga layin rufin gidan wuta na Acheson. Zafin zane yana tsakanin 1700-2500ºC. Yana cikin samfurin zane mai zafin jiki na themedium. Yana da ingantaccen recarburizer tare da babban carbon mai tsayayye, ƙarancin sinadarin sulfur, saurin narkewa da kuma yawan shan ruwa.
