Steel tube with yield strength being greater than 1138 MPa and used for drill pipe, and manufacturing method of steel tube

A yield strength and manufacturing method technology, which is applied to steel pipes for drill pipes with yield strength greater than 1138MPa and their manufacturing fields, can solve the problems of long manufacturing cycle of drill pipes and low production efficiency, and achieves improvement in strength and toughness, hardenability, Improves strength and impact absorption energy

Active Publication Date: 2018-07-13
BC P INC CHINA NAT PETROLEUM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The currently designed high-strength drill pipe with a yield strength of 1138MPa is mainly obtained by adjusting the content of alloying elements such as Mn and Mo in the material on the basis of ordinary drill pipe materials, or adding strengthening elements such as V, and obtaining it through modulation heat treatment. The high temperature tempering is cooled by air cooling, the manufacturing cycle of the drill pipe is long and the production efficiency is low

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027]According to the composition in the following table 1, it was smelted into a round steel billet. After the steel billet is evenly heated at 1050°C, it is rolled and pierced, and the final rolling temperature is controlled at 1000°C; the steel pipe is heated to 930°C and kept for 40 minutes, and then the steel pipe is cooled to room temperature with water as the cooling medium; the cooled steel pipe is heated to 600 ℃, heat preservation for 50 minutes, and rapid cooling to room temperature with water as the cooling medium. The mechanical properties of the obtained steel pipes are shown in Table 2.

[0028] Table 1 shows the chemical composition of steel pipes for drill pipes in Examples 1 to 3 of the present invention, and Table 2 shows the test results of Examples 1 to 3 of the present invention. The strength and toughness are obviously better than those shown in Table 3. Kind of steel pipe. The manufacturing method of embodiment 2 and embodiment 3 is the same as embodi...

Embodiment 4

[0036] According to the following composition, it is smelted into a round billet, and its chemical composition (mass percentage) is C: 0.22%, Si: 0.20%, Mn: 0.4%, Cr: 1.6%, Mo: 0.7%, Ni: 1.9%, Nb: 0.15%, S: 0.003%, P: 0.009%, and the rest are iron and unavoidable impurities. After the steel billet is evenly heated at 1000°C, it is rolled and pierced, and the final rolling temperature is controlled at 900°C; the steel pipe is heated to 900°C, kept for 50 minutes, and then the steel pipe is cooled to room temperature with water as the cooling medium; the cooled steel pipe is heated to 580 ℃, keep warm for 60 minutes, and quickly cool to room temperature with water as the cooling medium.

Embodiment 5

[0038] According to the following composition, it is smelted into a round billet, and its chemical composition (mass percentage) is C: 0.26%, Si: 0.15%, Mn: 0.7%, Cr: 1.3%, Mo: 1.0%, Ni: 1.8%, Nb: 0.11%, S: 0.002%, P: 0.007%, and the rest are iron and unavoidable impurities. After the steel billet is evenly heated at 1100°C, it is rolled and pierced, and the final rolling temperature is controlled at 1050°C; the steel pipe is heated to 950°C, kept for 30 minutes, and then the steel pipe is cooled to room temperature with water as the cooling liquid; the cooled steel pipe is heated to 620 ℃, keep warm for 30 minutes, and quickly cool to room temperature with water as the cooling medium.

[0039] The steel pipe for drill pipe of the present invention has a yield strength greater than 1138MPa, a tensile strength greater than 1206MPa, an elongation greater than 13%, and a longitudinal impact absorption energy higher than 100J at -20°C, which improves the strength and toughness of ...

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Abstract

The invention relates to a steel tube with the yield strength being greater than 1138 MPa and used for a drill pipe, and a manufacturing method of the steel tube. The manufacturing method comprises the steps that a steel billet is formed by smelting according to the following components of, by mass, 0.22-0.28% of C, 0.15-0.20% of Si, 0.4-0.7% of Mn, 1.3-1.6% of Cr, 0.7-1.0% of Mo, 1.5-1.9% of Ni,0.07-0.15% of Nb, no more than 0.004% of S, no more than 0.01% of P, and the balance iron and unavoidable impurities; the steel billet is evenly heated and is subjected to rolling and perforation to obtain the steel tube; and the steel tube is subjected to heat treatment and is water-cooled to the room temperature, and the steel tube with the yield strength being greater than 1138 MPa and used forthe drill pipe is obtained. According to the steel tube with the yield strength being greater than 1138 MPa and used for the drill pipe, and the manufacturing method of the steel tube, by reasonablycontrolling the content of C, Si, Cr, Mn, Mo, Ni, Nb, S and P elements, uniform and fine texture is ensured by adopting the water cooling mode, and meanwhile, deformation and residual stress are controlled in a very low range to ensure high-strength toughness matching of the drill pipe.

Description

technical field [0001] The invention relates to a steel pipe for a drill pipe and a manufacturing method thereof, in particular to a steel pipe for a drill pipe with a yield strength greater than 1138 MPa and a manufacturing method thereof. Background technique [0002] Drill pipe is an important tool for oil and gas drilling operations. In order to meet the needs of deep oil and gas drilling development, drill pipe manufacturers have successively designed and developed high-strength drill pipes with a strength of 1138MPa (165ksi). Patent CN103938095B proposes a 165ksi steel grade high-strength and high-toughness drill pipe and its manufacturing method, its composition mass percentage is C: 0.20-0.40%, Mn: 0.50-1.40%, Cr: 0.50-1.40%, Mo: 0.60-2.10 %, Ti: 0.005~0.025%, Nb: 0.03~0.10%, V: 0.02~0.15%, Si: 0.20~0.40%, Al≤0.05%, N≤0.10%, P≤0.015%, S≤0.008%, The rest is iron and unavoidable impurities. And Mn decrease value=(3~6)×C increase value, [Nb]+[V]+[Ti]≤0.25%, 5≤[Nb] / [T...

Claims

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Application Information

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IPC IPC(8): C22C38/02C22C38/04C22C38/44C22C38/48C21D8/10C21D1/18
CPCC21D1/18C21D8/105C22C38/002C22C38/02C22C38/04C22C38/44C22C38/48
Inventor 李方坡王建军冯耀荣韩礼红
Owner BC P INC CHINA NAT PETROLEUM CORP
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