单项选择题
A.T9 B.9Mn2V C.9Cr18 D.MnCrWV
A.T9 B.9Mn2V C.1Cr18Ni9Ti D.45
A.T7A B.T8A C.T10A D.T12A
A.0.1%-0.5% B.0.5%-0.7% C.0.7%-1.3% D.1.5%-2%
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