Carbon dioxide corrosion resistant seamless steel pipe and preparation method thereof

A seamless steel pipe, carbon dioxide technology, applied in the field of pipeline steel manufacturing, can solve the problems of early corrosion failure, high cost, pipeline pitting and perforation, etc., and achieve excellent carbon dioxide corrosion resistance, low cost, corrosion resistance and economy. good effect

CN111218624AActive Publication Date: 2020-06-02UNIV OF SCI & TECH BEIJING
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2020-06-02

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Abstract

The invention provides a carbon dioxide corrosion resistant seamless steel pipe and a preparation method thereof, and relates to the technical field of pipeline steel manufacturing. A prepared steel pipe has excellent carbon dioxide corrosion resistant performance, the corrosion rate of the steel pipe is lower than 0.06 mm / a, and the manufacturing cost is low. The steel pipe comprises the components of 0.03-0.08% of C, 5.50-8.5% of Cr, 0.1-2% of Ni, 0.010-0.055% of Nb, 0-0.012% of P, 0-0.006% of S, 0-0.010% of N and the balance Fe and inevitable impurities. The method comprises the steps of S1, conducting smelting and pouring to obtain a steel ingot according to the mass ratio of the components; S2, conducting forging and primary annealing; S3, conducting secondary annealing; S4, rolling apipe to obtain a pipe blank; and S5, conducting heat treatment. The technical scheme provided by the invention is suitable for the seamless steel pipe preparation process.
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Description

Technical field

[0001] The invention relates to the technical field of pipeline steel manufacturing, in particular to a carbon dioxide corrosion-resistant seamless steel pipe and a preparation method thereof.

Background technique

[0002] In recent years, with the gradual increase in the demand for oil and gas energy, the development of deep oil and gas wells has been intensified. The traditional mining and transportation technology can no longer meet the demand, and the use of CO 2 Oil flooding can effectively enhance the recovery of low-permeability oilfields. Generally speaking, dry carbon dioxide is not corrosive, but it is extremely corrosive to steel in a humid environment or after being dissolved in water. After being dissolved in water, its total acidity is higher than that of hydrochloric acid at the same concentration, and its corrosion of steel is more serious than that of strong acid. Carbon dioxide corrosion may greatly shorten the actual service life of ...

Examples

preparation example Construction

[0037] Prepare the preparation method of above-mentioned carbon dioxide corrosion resistant seamless steel pipe, such as figure 1 As shown, the steps include:

[0038] Step 1, smelting and pouring steel ingots according to the composition of the above-mentioned seamless steel pipe;

[0039] Step 2. After smelting, the steel billet needs to be forged. The characteristics are: the heating temperature is not less than 1150°C, followed by forging, and the forging billet is annealed after forging. The temperature is 800-900°C, and the holding time is set at 3-5min / mm, cooling rate≤30℃ / h;

[0040] Step 3. Tube rolling process after forging, which is characterized in that: after forging, the round billet is annealed at 650-750°C, the annealing process is heat preservation in the furnace for 3-4 hours, and the annealed tube billet is heated at 1150-1200°C for 1.5-1.5 hours After 2 hours, use a conical piercer to perforate, and then pass through a sizing machine or a stretching and ...

Embodiment 1

[0069] The microstructure and morphology of the seamless steel pipe prepared in embodiment 1 and embodiment 2 are as follows: figure 2 with image 3 shown. As can be seen from the figure, in Example 1, the Cr content is close to the lower limit, and the Ni content is close to the upper limit. In Example 2, the Cr content is close to the upper limit, and the Ni content is close to the lower limit. near the endpoint. The structures of the two examples are both bainite + a small amount of ferrite, the structure is uniform, there is no obvious inclusion, and the comprehensive mechanical properties and corrosion resistance are good, which also shows that the present invention can achieve the expected effect within the composition range of the application.

[0070] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0071] Since Cr and C in steel are easy to form Cr carbides, adding Cr to carbon steel alone cannot achieve the expected c...