Vim li cas Kub-dip Galvanized Rectangular Steel Pipes thiaj li nrov?

① Siab zog, khoov thiab compression kuj, haum rau cov qauv;
② Zoo tiv thaiv- corrosion, txij nkawm- dawb thiab qis nqi;
③ Zoo zoo thiab zoo nkauj tsos, yooj yim rau nruab;
④ tuaj yeem welded, drilled, sib dhos, thiab muaj ntau yam;
⑤ Tus nqi yog nruab nrab thiab tus nqi -kev ua tau zoo piv yog siab heev.