J55 grade steel for resistance welding casing with low yield strength ratio and its manufacturing method

A low yield ratio, resistance welding technology, applied in J55 grade ERW oil casing steel and its manufacturing field, can solve the problems of weldability, impact toughness and formability, low tensile strength, high yield strength, etc., to achieve yield No significant increase in strength, high tensile strength, and low yield strength

Active Publication Date: 2017-10-27
ANGANG STEEL CO LTD
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  • Application Information

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Problems solved by technology

[0018] The present invention aims at the technical problems existing in the current production of J55 grade ERW oil casing steel, such as high C content, high yield strength, low tensile strength, general weldability, impact toughness and formability, etc., and provides a direct Steel for seam resistance welding oil casing and its manufacturing method, especially low yield ratio J55 grade ERW oil casing steel with good weldability, impact toughness and formability, and its manufacturing method

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  • J55 grade steel for resistance welding casing with low yield strength ratio and its manufacturing method
  • J55 grade steel for resistance welding casing with low yield strength ratio and its manufacturing method
  • J55 grade steel for resistance welding casing with low yield strength ratio and its manufacturing method

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Embodiment Construction

[0039] Its chemical composition (weight, %) ratio is as follows: C: 0.090% ~ 0.128%, Si: 0.10% ~ 0.35%, Mn: 1.02% ~ 1.25%, P: ≤0.015%, S: ≤0.008%, Nb: 0.01% to 0.03%, Ti: 0.010% to 0.030%, Cr: 0.30% to 0.40%, Als: 0.02% to 0.06%, N: ≤0.008%, and the rest are Fe and unavoidable elements.

[0040] Its characteristics are:

[0041] 1) Smelting and continuous casting process: molten iron pretreatment, converter smelting - through top blowing or top-bottom composite blowing, refining outside the furnace - LF furnace light desulfurization treatment, and calcium treatment to control the shape of inclusions and improve the ductility of steel, Toughness and cold bending performance, continuous casting of slabs to make continuous casting slabs - continuous casting adopts electromagnetic stirring or dynamic light reduction to improve the quality of continuous casting slabs.

[0042] 2) Rolling process: the continuous casting slab is heated to 1160-1200°C by the heating furnace, and then...

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Abstract

The invention discloses a J55 grade low-yield-strength-ratio resistance welding casing steel and a manufacturing method thereof. %, P: ≤0.015%, S: ≤0.008%, Nb: 0.01%~0.03%, Ti: 0.010%~0.030%, Cr: 0.30%~0.40%, Als: 0.02%~0.06%, N: ≤0.008 %, the rest is Fe and unavoidable elements, and the method is characterized by: the continuous casting slab is heated to 1160-1200°C by a heating furnace, the final rolling temperature of the first stage is greater than 980°C; the starting rolling temperature of the second stage is 980-1020°C , the final rolling temperature is 810-865°C; the rolled steel strip adopts laminar intermittent cooling, and the cooling rate is 12-18°C / s; it is coiled at 590-680°C. The advantages and effects of the present invention are: the carbon content is relatively Low, good weldability and impact toughness; appropriate amount of Cr alloy is added, the safety of the steel pipe is good, and the yield strength and tensile strength are guaranteed to meet the standard requirements.

Description

technical field [0001] The present invention relates to a steel for straight seam electric resistance welded oil casing (ERW / HFW for short) and a manufacturing method thereof, in particular to a J55 grade ERW oil casing steel with a low yield ratio in API SPEC 5CT and a manufacturing method thereof . Background technique [0002] Oil casing is one of the most commonly used oil-specific pipes in oil fields. The annual demand is about 800,000 to 1 million tons, accounting for more than 40% of the total steel used in the oil industry. It is an indispensable construction in oil and gas field drilling operations. Material. 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. In particular, J55 grade ERW casings have mostly replaced traditional seamless pipes. Seam steel pipe. [0003] API Spec 5CT stipulates that the yield strength...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22C38/28C21D8/02
Inventor 黄明浩黄国建孔祥磊张英慧栗锐
Owner ANGANG STEEL CO LTD
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