A high-strength resistance welding sleeve and its manufacturing method

Abstract

The invention provides a high-strength electric resistance welding casing pipe and a manufacturing method thereof. The casing pipe comprises, by weight percentage, 0.26-0.30% of C, 0.15-0.30% of Si, 1.30-1.60% of Mn, less than or equal to 0.020% of P, less than or equal to 0.008% of S, 0.010-0.030% of Ti, 0.02-0.05% of Als, 0.36-0.46% of Cr, less than or equal to 0.008% of N and the balance Fe and inevitable elements. The manufacturing method comprises the steps of smelting and continuous casting, reheating of a casting blank, rolling, cooling, reeling, pipe manufacturing conducted through ERW and heat treatment conducted on the whole pipe, wherein hot continuous rolling is conducted after heating is completed, the finish rolling temperature is 840-900 DEG C, and a rolled steel strip is cooled at the cooling speed of 5-10 DEG C / s and reeled at the temperature of 630-680 DEG C; and after pipe manufacturing conducted through ERW is completed, the whole pipe is heated to 880-940 DEG C, the temperature is preserved for 60-80 minutes, and water cooling is conducted. According to the high-strength electric resistance welding casing pipe and the manufacturing method thereof, medium carbon and Cr-containing design is adopted, and alloy cost is low; the plate roll structure in the hot-rolling state is ferrite-pearlite, and subsequent pipe manufacturing and formation can be conducted easily; and the whole pipe is subjected to quenched-tempered heat treatment, the final structure is tempered sorbite, the casing pipe is at the level of P110 in performance, and performance consistency of a pipe body and welding seams is guaranteed.

Description

technical field [0001] The invention belongs to the field of high-strength low-alloy steel, and in particular relates to a straight seam resistance welding sleeve and a manufacturing method thereof. Background technique [0002] Oil casing is one of the most commonly used petroleum-specific pipes in oil fields. It consumes a lot of money and costs a lot. It is an indispensable construction material in oil and gas field drilling operations. At present, the development of many oilfields in my country has entered the middle and late stages, and the development difficulty is becoming more and more difficult, especially in deep wells, which put forward higher requirements for casing performance. Therefore, it is urgent to develop high-performance straight seam resistance welding casing. It has far-reaching significance to save the cost of oil extraction and improve the level of oil extraction in our country. [0003] Compared with seamless pipes, electric resistance welded (ERW...

AI Technical Summary

Problems solved by technology

[0013] Aiming at the technical problems existing in the current production of straight seam resistance welded petroleum casing P110, for example: adding more precious alloys Mo, Ni, Cu, Nb, V, the cost of the alloy is high; the strength of the hot-rolled state reaches P110, and it is difficult to make a tube with high strength, etc. problem, the technical scheme of the present invention is proposed

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