单项选择题
A.灰铸铁 B.球墨铸铁 C.可锻铸铁 D.蠕墨铸铁
A.Z≤3% B.A≥3% C.Rm≥3% D.ReL≤3%
A.15% B.0.2-0.6% C.0.7-1.65% D.0.95-1.15%