A.GB/T228 B.GB/T230 C.GB/T232 D.GB/T238
A.碳素結(jié)構鋼 B.低碳結(jié)構鋼 C.低碳鋼熱軋圓盤條 D.熱軋光圓鋼筋
A.碳 B.氧 C.硫 D.釩