单项选择题
A.30~40mm B.40~60mm C.60~100mm D.100~150mm
A.3% B.5% C.8% D.10%
A.淬火+低温回火 B.淬火+中温回火 C.淬火+低温回火或淬火+高温回火 D.淬火+高温回火
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