A.D≈(30~50)根號(hào)Qn(mm) B.D≈(20~25)根號(hào)Qn(mm) C.D≈S/0.75(mm)
A.電渣重溶 B.電爐冶煉 C.氧氣頂吹轉(zhuǎn)爐冶煉
A.石棉芯 B.金屬芯 C.有機(jī)芯