... to certain spacing and cross bar (twisted square steel, square steel, round steel, flat steel, etc.) to cross arranged, and welded into the middle ... galvanizing, can rise to prevent oxidation. Also can use stainless steel. The steel case board with ventilation, lighting, cooling, non-slip, explosion ... bearding flat bars(mm)12.5,15, 20, 30, 30.6, 32.5, 34, 34.8, 35.3, 40, 60, 80……Pitch of ...