Cov pa roj carbon steel yeeb nkab ntau lawm txoj kev (1) seamless steel yeeb nkab- kub dov raj, txias drawn tube, extruded raj, sab saum toj raj, txias dov raj (2) welded steel yeeb nkab (A) raws li cov txheej txheem- arc welded kav, hluav taws xob kuj welded yeeb nkab (high-frequency, tsawg zaus), roj yeeb nkab, rauv weld ...
Nyeem ntxiv