... . 4,API 5CT-1043, API 5L-0699 Linzhou Fengbao Pipe Co.,Ltd. as a seamless pipe manufacturer in the worldwide marketplace specializes ... 9001:2008 Quality system certification and API certification get passed. Manufacturing MethodHot rolled seamlessSize (OD)Casing:4-1/2”,5”,5 ... -Layer Polypropylene coated seamless steel pipe manufacturer Linzhou Fengbao Pipe Co.,Ltd.