A.45 B.40Cr C.16Mn D.ZGMn13
A.T12鋼經(jīng)淬火和低溫回火 B.Cr12MoV鋼經(jīng)淬火和低溫回火 C.65鋼經(jīng)淬火后中溫回火
A.銅 B.鋅 C.鎂 D.鋁