A.16MnR,Q235-B,20R B.16MnR,20R,Q235-B C.20R,16MnR,Q235-B D.Q235-B,20R,16MnR
A.25 B.30 C.15 D.12.5
A.拼接長度≥500,直管允許1條;U形管允許2條焊縫 B.拼接長度≥300,直管不允許;U形管允許1條焊縫 C.拼接長度≥500,直管不允許;U形管允許1條焊縫 D.拼接長度≥300,直管允許1條;U形管允許2條焊縫