A.-0.020~+0.020 B.-0.05~+0.020 C.-0.020~+0.050 D.-0.015~+0.015
A.≤0.05 B.≤0.01 C.≤0.50 D.≤0.02
A.高碳合金鋼 B.低碳合金鋼 C.碳素工具鋼 D.鑄鋼