... pre-engineering steel structure warehouse/steel structure building/factory construction Qingdao Baoduo Steel Structure CO.,LTD.Main Grade: Q345B,Q235B Standard:ISO9001,BV ... ,Hanger,Agricultral storage,Logistic centers,and all kinds of steel materials.,etc.Specifications:Main Steel: Q345B,Q235BColumn&Beam: Welded or Hot rolled ...