Evaluation of Applicability of Long-term Stored Seamless Steel Tube

Evaluated is the applicability of a certain lot of long-term stored seamless steel tubes via test analysis.The results of the tests with specimens from the tube show that tubes of the lot are still up to the requirements as specified under Standard GB/T 9711—2011 in terms of geometric dimensions,physiochemical property,full-scale hydrostatic test and explosion test.The brown corrosive substance on the inner surface of the tube is identified as the oxide,mainly Fe₂O₃.However due to a rather long storage period,a layer of floating rust is attached on the inner surface,and causes slight and corrosion.Accordingly it is suggested to provide corrosion preventative measures at the late stage of the piping construction,and meanwhile carry out periodic check of the piping inner surface corrosion status during subsequent period after the piping is running.