单项选择题
A.≤0.04%B.0.04～0.25%C.0.25～0.60%
A.洛氏硬度B标尺 B.表面洛氏硬度 C.布氏硬度
A.10³10³55mm B.10³7.5³55mm C.10³5³55mm
A.20%80% B.10%90% C.15%90%
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