... heads with cap small dia pipe Seamless steel pipe/seamless pipe/steel tube(1)Surface treatment:coated black, ... ,API5CT,GB/T8163,GB/T8162.(3)Steel grade:Q235,Q345,STEEL ROUND PIPE SIZE-OD IN INCH ... projects, boiler , steel scaffolding in building, water conservancy project, aviation,construction, machinery manufacturing, steel construction projects, shipbuilding, steel structure engineering, electrical ...