690MPa-grade electric resistance welding petroleum sleeve and manufacture method thereof

Abstract

The invention provides a 690MPa-grade electric resistance welding petroleum sleeve and a manufacture method of the 690MPa-grade electric resistance welding petroleum sleeve. The 690MPa-grade electric resistance welding petroleum sleeve is prepared by the following chemical components in percentage by weight: 0.15 to 0.23% of C, 0.15 to 0.30% of Si, 1.25 to 1.58% of Mn, not greater than 0.020% of P, not greater than 0.008% of S, 0.010 to 0.030% of Ti, 0.02 to 0.05% of Als, 0.020 to 0.048% of V, not greater than 0.008% of N, and the balance of Fe. The manufacture method comprises steps as follows: smelting, continuously casting, rolling, preparing a pipe, and thermally processing the whole pipe; after heated to reach a temperature of 1180 to 1280 DEG C, a slab blank is rolled in two stages, wherein initial rolling in the first stage is at the temperature of 1130 to 1280 DEG C, and final rolling is at the temperature more than 960 DEG C; and the initial rolling in the second stage is at the temperature less than 950 DEG C, and the final rolling temperature is 760 to 850 DEG C; then rolled slab blank is rolled at the temperature of 8 to 18 DEG C per second after rolling, and coiled at the temperature of 560 to 640 DEG C; after being manufactured, the whole pipe processed by heating reach the temperature of 880 to 940 DEG C, maintaining the temperature for more than 30 minutes; quenching by water, then heating to reach the temperature of 520 to 560 DEG C, maintaining the temperature for more than 25 minutes, cooling in air, and tempering. The manufacture method is low in cost of an alloy; a coiled plate is high in welding performance and impact toughness, so that the pipe can be easily manufactured and formed in a later period.

Description

technical field [0001] The invention belongs to the technical field of high-strength low-alloy steel, and relates to an ERW (ERW, Electric Resistance Weld, resistance welding) casing and a manufacturing method thereof, in particular to an N80Q petroleum casing with a tensile strength of 690MPa in API SPEC 5CT The pipe and its manufacturing method, the performance of the hot-rolled steel strip is J55 steel grade, and the performance of the whole pipe after quenching and tempering is N80Q steel grade. 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. Compared with seamless pipes, ERW casings have significant advantages such as uniform wall thickness, high dimensional accuracy, good perforation performance, strong collapse resistance, and low cost. [0003] API SPEC 5CT stipulates that...

AI Technical Summary

Problems solved by technology

In this paper, precious alloy elements Mo and Nb are added, and the cost of the alloy is high

[0013] In the above disclosed patents or documents, some add more precious alloys Mo, Nb, V, and the alloy cost is high; some have high carbon content, and the steel strip has poor toughness; some have high carbon equivalent, and the steel strip has poor weldability

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