A.60Si2Mn B.65Mn C.T7A D.GCr15
A.普通碳鋼 B.鋼的屈服點(diǎn) C.普通結(jié)構(gòu)鋼 D.優(yōu)質(zhì)鋼
A.灰鑄鋼 B.可鍛鑄鋼 C.球墨鑄鋼 D.合金鑄鋼