单项选择题
A.沸腾钢 B.半镇静钢 C.镇静钢 D.转炉钢
A.S≤0.055%、P≤0.045% B.S、P均≤0.040% C.S≤0.030%、P≤0.035% D.S≤0.055%、P≤0.065%
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