Large-expansion steel for seamless steel tube and preparation method thereof

A technology of seamless steel pipe and expansion, which is applied in the field of seamless steel pipe, can solve the problems of reducing production efficiency, increasing process cost, and heat treatment process is unfavorable for large-scale industrial production, and achieves the effect of solving high cost and high plastic deformation ability

Active Publication Date: 2013-06-12
CENT IRON & STEEL RES INST
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] Second, the manufacturing process is complex
For example, in the preparation method of N80 steel grade expansion pipes disclosed in Chinese patent CN 102534369 A, the ideal matching of strength and toughness can be obtained only after two times of quenching and tempering in the two-phase zone, and complicated heat treatment The process is not conducive to large-scale industrial production, which increases the cost of the process and reduces the production efficiency

Method used

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  • Large-expansion steel for seamless steel tube and preparation method thereof
  • Large-expansion steel for seamless steel tube and preparation method thereof
  • Large-expansion steel for seamless steel tube and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1 and Embodiment 2

[0035]Low-cost and large-expansion seamless petroleum casing, the composition of raw materials in terms of mass percentage is: C: 0.03wt%, Si: 0.3wt%, Mn: 5.8wt%, P: 0.01wt%, S: 0.0020wt%, The balance is Fe and unavoidable impurities, which are smelted and cast into steel billets by converter.

[0036] Using the seamless tube forming technology, the above-mentioned tube blank is heated to 1200°C, soaked and perforated. After rolling at 900 °C, two cooling methods, air cooling and water spray cooling, were used to obtain two room temperature microstructures, such as figure 1 and figure 2 shown. Finally, the steel pipes of these two structures were heated to 650°C at a heating rate of 5°C / S, and after holding for 8 hours, they were cooled to room temperature with the furnace. The final microstructure is obtained as image 3 and Figure 4 shown.

[0037] After inspection, the mechanical properties of steel pipes under the two cooling methods are shown in Table 1. Its vari...

Embodiment 3~ Embodiment 6

[0041] Low-cost large-expansion seamless petroleum casing, the composition of raw materials in terms of mass percentage is: C: 0.02~0.08wt%, Si: 0.3wt%, Mn: 3~8wt%, P≤0.015wt%, S≤0.0030 wt%, and the balance is Fe and unavoidable impurities. The specific chemical cost is shown in Table 2. It is smelted in a converter and cast into a steel billet.

[0042] Using the seamless tube forming technology, the above-mentioned tube blank is heated to 1200°C, soaked and perforated. Water spray cooling is used after rolling at 900°C. Finally, the steel pipes of these two structures were heated to 630°C at a heating rate of 5°C / S, and after holding for 10 hours, they were cooled to room temperature with the furnace.

[0043] After inspection, the mechanical properties of several steel pipes with different chemical compositions are shown in Table 3. Its various mechanical performance indicators fully meet the requirements of API and other relevant standards.

[0044] Table 2 Chemical co...

Embodiment 7~ Embodiment 10

[0049] Large expansion capacity seamless petroleum casing, the raw materials are: C: 0.04wt%, Si: 0.3wt%, Mn: 5.0wt%, P: 0.012wt%, S: 0.0020wt%, the balance It is Fe and unavoidable impurities. It is smelted in a converter and cast into a steel billet.

[0050] Using seamless tube forming technology, the above-mentioned tube blank is heated to 1150 ℃ ~ 1200 ℃, soaked and pierced. Water spray cooling is adopted after rolling at 800~1000°C. Finally, the steel pipes were heated to 610°C, 630°C and 650°C at a heating rate of 5°C / S, respectively, and then kept at different times, and then cooled to room temperature with the furnace. The specific heat treatment process is shown in Table 4.

[0051] After inspection, the mechanical properties of several steel pipes with different chemical compositions are shown in Table 5. Its various mechanical performance indicators fully meet the requirements of API and other relevant standards.

[0052] Table 4 Detailed heat treatment proces...

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Abstract

The invention discloses large-expansion steel for a seamless steel tube and a preparation method thereof, and belongs to the technical field of the seamless steel tube. The large-expansion steel comprises the chemical ingredients by mass percent: 0.02-0.10wt% of C, 2.0-8.0wt% of Mn, 0.2-1.0wt% of Si, less than 0.01wt% of S, less than 0.02wt% of P, the balance of Fe and inevitable impurities; and one or more other chemical elements can be added on the basis, including 0.1-0.6wt% of Ni, 0.1-0.6wt% of Cr, 0.1-0.5wt% of Cu, 0.01-0.1wt% of Nb, 0.01-0.1wt% of V, and 0.01-0.02wt% of Ti. The preparation process comprises the steps of smelting and condensing steel, heating and perforating a tube blank, controlling cooling, and annealing a two-phase area. The retained austenite of which the volume fraction is greater than 5% is finally obtained in the tissue. The large-expansion steel has the advantages that the large-expansion steel has high plasticity when ensuring that the material has high strength level; the uniform elongation achieves over 20%; and each mechanical performance index meets the American Petroleum Institute (API) and other related standard requirements.

Description

technical field [0001] The invention belongs to the technical field of seamless steel pipes, and in particular relates to a large-expansion steel for seamless steel pipes and a manufacturing method thereof, which are economical, practical and low in cost. Background technique [0002] Expandable pipe technology is an emerging technology to reduce the cost of oil drilling and completion. It is known as one of the "core technologies of the oil drilling industry in the 21st century" and is increasingly attracting widespread attention in the industry. The expandable tube is a new type of casing that undergoes mechanical expansion, deformation and expansion after going into the well. It can be widely used in drilling, well completion, oil production, well workover and other operations. The emergence of this technology has fundamentally changed the deep well and complex geological conditions in the future. oil drilling technology. The core advantage of the expandable tubular tech...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/04C22C38/58C22C33/04C21D8/10
Inventor 刘清友贾书君汪兵陈红桔
Owner CENT IRON & STEEL RES INST
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