Black Iron Square Tube zakuthupi ndi ozizira adagulung'undisa mpweya zitsulo lamba ndi khoma makulidwe 0.6mm kuti 2.0mm.Chingwe chachitsulo chozizira chikatenthedwa ndi kutentha kwa annealing, mtundu wamtunda umasanduka wakuda chifukwa cha kutentha kwambiri kukhudzana ndi mpweya.Amatchedwanso ozizira adagulung'undisa wakuda annealed lalikulu chubu amene chimagwiritsidwa ntchito zitsulo kapangidwe.