单项选择题
A.促进石墨化B.提高机械性能C.脱氧D.脱硫
A.1.31B.1.41C.1.51D.1.71
A.0.10%〜0.30%B.0.30%〜0.50%C.0.50%〜0.80%D.0.80%〜0.90%