Steel used for straight seam electric resistance welding petroleum casing and casing manufacturing method

Abstract

The invention relates to a steel used for straight seam electric resistance welding petroleum casing and a casing manufacturing method, which is applied to a straight seam electric resistance welding petroleum casing used for an oil and gas well in petroleum and gas industry. The steel used for the straight seam electric resistance welding petroleum casing comprises the following components in percentage by mass: 0.15-0.28% of C, 1.0-1.6% of Mn, 0.2-0.4% of Si, 0. 02-0.06% of Al, less than or equal to 0.01% of P, less than or equal to 0.005% of S, less than or equal to 0.008% of N, 0.001-0.005% of Ca and the balance of Fe. The preparation method comprises the steps of: preparing hot-rolled plate coils, producing straight seam electric resistance welding steel pipes by the hot-rolled plate coils, carrying out welding seam normalization or overall normalization on the welded steel pipes, straightening and cutting the normalized or tempered welded steel pipes into pipe segments with the length of 10-12m, and processing API standard screw threads. The invention has the advantages that the steel has good strength and toughness, the welding seam has no defect, and the properties of the steel are uniform with those of mother material. The yield strength is greater than or equal to 380-760MPa, the tensile strength is greater than or equal to 520-865MPa, the elongation is greater than or equal to 20%, and the impact energy of a room-temperature transverse full-size V-shaped notch is greater than or equal to 40J.

Description

technical field

[0001] The invention relates to a steel for straight seam resistance welding oil casing for oil and gas wells in the petroleum and natural gas industry and a manufacturing method thereof. The straight seam electric resistance welded oil casing manufactured with the provided material and process has good comprehensive performance and meets the needs of oil and gas well drilling and well completion. Background technique

[0002] The use of straight seam resistance welding method to produce petroleum casing has the characteristics of high production efficiency; because the hot-rolled coils used in resistance welding are produced by controlled rolling method, they have high wall thickness accuracy. The precision is also very good; together with the development of welding technology and the progress of non-destructive testing technology, the quality of LSW pipe has been greatly improved, and its high yield also shows its good economy. However, quality accidents i...