[Jie Weinuo Star recommendation - angle iron flange Duct Duct] Jie Weinuo Industrial provide finished products, semi finished Tianjin angle iron flange duct, duct material enough, fabrication and installation of fire ventilation engineering. [Jie Weinuo Industrial Co., Ltd. Star recommendation] angle iron angle iron flange duct duct flange angle iron flange structural strength of stronger wind pipe plant in Tianjin, no welding, no riveting, all galvanized angle iron manufacturing method Tianjin Lan duct quality, good corrosion resistance, Tianjin tight angle iron flange connection duct leakage rate. Duct finished its appearance, size, accurate rules, shape, smooth lines, air leakage is far below national standards.