A.5~13B.20~25C.30~35D.40~50
A.0.1%~0.2%B.0.2%~0.4%C.0.4%~0.6%D.0.7%~1.2%
A.沖天爐B.感應(yīng)爐C.沖天爐與感應(yīng)爐雙聯(lián)D.電阻爐