1. Muab faib los ntawm txoj kev tsim khoom
(1) Seamless yeeb nkab -- kub dov yeeb nkab, txias dov yeeb nkab, txias drawn yeeb nkab, extrusion yeeb nkab, yeeb nkab jacking
(2) Vuam yeeb nkab
(a) Raws li cov txheej txheem - arc vuam yeeb nkab, tsis kam vuam yeeb nkab (siab zaus, tsawg zaus), roj vuam yeeb nkab, qhov cub vuam yeeb nkab
(b) Raws li cov welded, nws tuaj yeem muab faib ua cov yeeb nkab ncaj nraim thiab kauv welded yeeb nkab
2. Kev faib tawm los ntawm cov duab seem
(1) Tej yam yooj yim seem steel yeeb nkab -- round steel yeeb nkab, square steel yeeb nkab, oval steel yeeb nkab, daim duab peb sab steel yeeb nkab, hexagonal steel yeeb nkab, pob zeb diamond steel yeeb nkab, octagonal steel yeeb nkab, semicircular steel voj voog, lwm yam
(2) complex seem steel yeeb nkab -- tsis sib npaug hexagonal steel yeeb nkab, tsib valve plum zoo li tus steel yeeb nkab, ob chav convex steel yeeb nkab, ob chav concave steel yeeb nkab, melon zoo li tus steel yeeb nkab, conical steel yeeb nkab, corrugated steel yeeb nkab, watchcase steel yeeb nkab , lwm yam
3. Raws li cov phab ntsa thickness cais - nyias phab ntsa steel yeeb nkab, tuab phab ntsa steel yeeb nkab
4. Raws li kev siv cov kev faib tawm - cov yeeb nkab yeeb nkab, cov khoom siv thermal nrog cov yeeb nkab steel, kev lag luam nrog steel yeeb nkab, roj av, geological drilling nrog steel yeeb nkab, thawv steel yeeb nkab, tshuaj lom neeg kev lag luam nrog steel yeeb nkab, tshwj xeeb lub hom phiaj steel yeeb nkab, lwm yam
