A.20-40 B.40-60 C.60-80 D.80-100
A.1537-(88C%+8Si%+4Mn%+30P%+25S%) B.1537-(88C%+9Si%+5Mn%+30P%+25S%) C.1537-(88C%+8Si%+5Mn%+30P%+25S%) D.1537-(88C%+8Si%+5Mn%+30P%+29S%)
A.上下偏低,而中間溫高 B.上下偏高,而中間溫低 C.自上而下溫度遞減 D.都一樣