1. Khoom siv: Ordinary carbon structural steel (Q yield zog), high-quality carbon structural steel (nrog qhov nruab nrab carbon loj feem ntawm 20/10000), alloy structural steel (nrog ib tug nruab nrab manganese pawg ntawm txog 2% nyob rau hauv 20Mn2), cam khwb cia hlau (ZG230-450 tsawg tshaj li 20 ...
Nyeem ntxiv