... Donghai Steel Pipe Co., Ltd. name seamless steel pipe for oil fieldBrand namedonghai steel pipeStandardAPI 5CT ,API 5L,ASTM A53, ... /T8163-2008,GB3087-2008,GB5310-2008,GB6479-2000,GB9948-2006 Material St35.8, St44 ,St52, 20Mn2 ,10, 20,35 ... -30days for an order less than 1000 tonsSurface treatmentBlack paint, yellow/transparent an-ti rust oil, galvanizedUsagePetroleum, chemical, power, gas, industrial ...