STEEL PIPE FOR EMBEDDING-EXPANDING, AND METHOD OF EMBEDDING-EXPANDING OIL WELL STEEL PIPE

摘要

(1) A steel pipe that is expanded radially in a state wherein it was inserte d in a well such as an oil well, characterized in that the non-uniform wall thickness ratio E0 (%) before expanding satisfies the following expression ~ . E0 .ltorsim. 30 /(1 + 0.018 .alpha.) .multidot. ~ Wherein .alpha. is the pipe expansion ratio (%) calculated by the followin g expression ~. .alpha. = [(inner diameter of the pipe after expanding - inner diameter of t he pipe before expanding)/inner diameter of the pipe before expanding] .times. 100 .multidot.~ (2) A steel pipe that should be expanded radially in a state wherein it is inserted in a well, such as an oil well, characterized in that the eccentric non- uniform wall thickness ratio is 10 % or less. When the embedding-expanding method is performed with use of the steel pipe of (1) or (2), lowering of collapse strength of the expanded steel pipe is prevented and bending thereof can be decreased.