High-strength ERW welding socket steel, socket, method for producing same

A technology for welding sleeves and production methods, applied in the field of high-strength hot-rolled steel plates and ERW sleeves, can solve the problems of insufficient cooling capacity, the microstructure and mechanical properties of steel plates cannot meet the design requirements, and achieve significant economic and social benefits. , The effect of low alloy content and production cost saving

Active Publication Date: 2009-08-26
BAOSHAN IRON & STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

It is easy to realize the absence of martensite in the steel in terms of composition design or process control. The problem in on-site production is often that the lack of cooling capacity causes the austenite to decompose during the controlled cooling process, and finally makes the microstructure of the steel plate The structure and mechanical properties cannot meet the design requirements

Method used

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  • High-strength ERW welding socket steel, socket, method for producing same
  • High-strength ERW welding socket steel, socket, method for producing same
  • High-strength ERW welding socket steel, socket, method for producing same

Examples

Experimental program
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Effect test

Embodiment 1

[0037] In this embodiment, the mass percentages of the chemical composition of the steel for the welded casing and the casing are: C: 0.26; Si: 0.42; Mn: 1.19; Ti: 0.016; V: 0.19; Al: 0.007; Ca: 0.007; For Fe and unavoidable impurities.

[0038] The molten steel smelted in the converter is cast into a slab, and the slab is heated at 1200-1250°C and then hot-rolled into a strip. The final rolling temperature is 900°C. After rolling, the strip is air-cooled and coiled into a coil, and the cooling rate is 1°C. / s, or coiled into coils after laminar cooling to 610°C, the cooling rate is 18°C / s. After coil shearing and butt welding, coil forming, and ERW pipe making, heat treatment is performed on the weld seam at a heating temperature of 950°C±50°C to obtain ERW casing with mechanical properties meeting N80 steel grade.

[0039] After testing, the results of the mechanical properties of the bushing in this embodiment are as follows: R t0.5 Respectively 598MPa, 614MPa; R tm They...

Embodiment 2

[0041] The mass percentages of the chemical composition of the steel for the welded sleeve and the sleeve in this embodiment are: C: 0.29; Si: 0.30; Mn: 1.01; Nb: 0.021; Al: 0.035; the balance is Fe and unavoidable impurities.

[0042] The final rolling temperature is 880°C. After rolling, the strip is air-cooled and coiled into coils at a cooling rate of 1°C / s, or laminar cooled to 610°C and coiled into coils at a cooling rate of 6°C / s and 30°C / s. Others are with embodiment 1.

[0043] After testing, the results of the mechanical properties of the bushing in this embodiment are as follows: R t0.5 Respectively 612MPa, 653MPa, 680MPa; R tm They are 794MPa, 840MPa and 820MPa respectively.

Embodiment 3

[0045] The mass percent of the chemical composition of the steel for the welded casing and the casing in this embodiment is: C: 0.25; Si: 0.33; Mn: 1.22; V: 0.15; Cr: 0.52; B: 0.0032; Al: 0.02; unavoidable impurities.

[0046] After the slab is heated at 1250-1300°C, it is hot-rolled into a strip, and the final rolling temperature is 870°C. After rolling, the strip is air-cooled and coiled into coils at a cooling rate of 1°C / s, or laminar cooled to 570°C and coiled into coils at a cooling rate of 10°C / s and 15°C / s. Others are with embodiment 1.

[0047] After testing, the results of the mechanical properties of the bushing in this embodiment are as follows: R t0.5 Respectively 668MPa, 659MPa, 672MPa; R tm They are 842MPa, 879MPa and 885MPa respectively.

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Abstract

The invention provides high-strength ERW welding socket steel, which comprises the following chemical components in weight percentage: 0.18 to 0.30 percent of C, 0.15 to 0.50 percent of Si, 0.9 to 1.5 percent of Mn, 0 to 0.03 percent of Ti, 0.06 to 0.25 percent of V, 0 to 0.6 percent of Cr, 0 to 0.004 percent of B, 0.002 to 0.04 percent of Al, 0 to 0.01 percent of Ca, 0 to 0.05 percent of Zr, and the balance of Fe and inevitable impurities. The invention also provides a welding socket made of the steel and a method for producing the same. Hot rolled plate coils made by the steel produced by the invention can obtain a strengthened ferritic structure at different cooling rates, so the yield strength is insensitive to the cooling rate and the manufacturability of the welding socket is ensured.

Description

technical field [0001] The invention relates to a steel for oil casing, in particular to a high-strength hot-rolled steel plate, an ERW casing made of the steel plate and a production method thereof. Background technique [0002] Oil and gas development casings are generally produced and supplied according to API standards. According to the API standard, there are two types of oil casing pipes, seamless pipes and welded pipes. Compared with seamless pipes, welded pipes have remarkable features such as high production efficiency, good dimensional accuracy, wide specification range, and low cost. Therefore, they are the first choice of manufacturers and oilfield users, and have always been favored by the market. N80 steel grade ERW casing is a high-strength steel pipe. According to API standards, its yield strength R t0.5 Must be between 552-758MPa, tensile strength R tm Must be greater than 689MPa. The production process of ERW casing is: steelmaking-continuous casting-ho...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/32
Inventor 田青超董晓明
Owner BAOSHAN IRON & STEEL CO LTD
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