ST52 Concrete Pump Placement Pipe with SK Flange Material:ST52, 45Mn2, 20#,Q235 Brand: Schwing, PM, Sany, ... carried out carburizing chemical treatment on the inner wall.So it possess high wear-resistance4.service:we can supply OEM service ... -6inch F/MOthersproduct picture: ST52 Concrete Pump Placement Pipe with SK Flange