Normalized steel for resistance welding petroleum case pipe with low yield ratio, resistance welding casing tube and its manufacturing method

A technology of oil casing and low yield ratio, which is applied in the direction of casing, drilling pipe, manufacturing tools, etc., and can solve problems such as difficult to achieve

Active Publication Date: 2008-09-24
BAOSHAN IRON & STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, for ordinary carbon or low alloy st

Method used

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  • Normalized steel for resistance welding petroleum case pipe with low yield ratio, resistance welding casing tube and its manufacturing method
  • Normalized steel for resistance welding petroleum case pipe with low yield ratio, resistance welding casing tube and its manufacturing method

Examples

Experimental program
Comparison scheme
Effect test

Example Embodiment

[0042] Example 1-4:

[0043] The molten steel smelted in the converter and refined outside the furnace is continuously cast into billets after being treated with Ca. The continuous casting billet is heated at 1200 to 1250°C and then hot rolled into a strip with a thickness of 10mm. The final rolling temperature is greater than 850°C. After rolling, the strip is cooled to 570°C by laminar flow and then coiled into a coil. After shearing butt welding, coil forming, and ERW pipe making, the steel pipe is normalized and kept at 880~1100℃ for 40 minutes, and then the steel pipe is hot-straightened. The hot straightening temperature is greater than 400℃. Finally, the steel pipe is cooled in the air, and the pipe is processed to obtain the low yield ratio electric resistance welded petroleum casing of the present invention.

[0044] Table 2 shows the chemical composition of the normalized steel used for resistance welding of petroleum casing with low yield ratio in Examples 1-4 of the pr...

Example Embodiment

[0051] Example 5:

[0052] The mechanical properties of the hot-rolled coils in Examples 1-4 and Comparative Examples 1-2 were tested, and the results are shown in the table

[0053] Table 4 The mechanical properties of the hot rolled coils of Examples 1-4 and Comparative Examples 1-2

[0054]

Example Embodiment

[0055] Example 6:

[0056] The mechanical properties of the normalized resistance welded petroleum casing pipes obtained in Examples 1-4 and Comparative Examples 1-2 were tested, and the results are shown in Table 5.

[0057] Table 5 The mechanical properties of the casing of Examples 1-4 and Comparative Examples 1-2

[0058]

[0059] Combining Table 2, Table 3 and Table 5, it can be concluded that the strength of the resistance welded petroleum casing obtained in Examples 1 to 4 meets the requirements that the yield strength Rt0.5 is between 379 and 552 MPa, and the tensile strength Rm is greater than or equal to 655 MPa. Its flexural strength is low. The V content of Comparative Example 1 is slightly lower, and the tensile strength of the material is not up to the requirement, while the V content of Comparative Example 2 is too high, which makes the material too strong.

[0060] It can be seen from Table 4 and Table 5 that, due to the normalizing heat treatment of the welded p...

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Abstract

The invention provides an air hardening steel for oil casing with low yield ratio electrical resistance welding (ERW), an oil casing with low yield ratio electrical resistance welding which is made of the air hardening steel and a preparation method of oil casing. The components of the air hardening steel for oil casing with low yield ratio electrical resistance welding (ERW) in weight percent comprises: 0.19 to 0.29 percent of Carbon, 0.1 to 0.4 percent of Silicon, 1.0 to 1.3 percent of Manganese, less than or equal to 0.015 percent of Phosphorus, smaller than 0.008 percent of Sulfur, 0.002 to 0.04 percent of Aluminum, 0.001 to 0.01 percent of Calcium, 0.08 to 0.14 percent of Vanadium, the remaining part is Ferrum and other inevitable purities. The air hardening steel of the chemical proportion is adopted, continuously casted to form blank, the normalizing heat treatment is carried out for the entire casing after ERW of casing, and then the oil casing with low yield ratio electrical resistance welding of the invention is fabricated out. The yield strength of the oil casing is between 379 to 552 Megapascal, the tensile strength is greater than or equal to 655 Megapascal, and the oil casing has the moderate carbon equivalent and the stable mechanical property of the entire casing.

Description

technical field [0001] The invention relates to a steel for oil casing, in particular to a normalizing steel for electric resistance welding (ERW) oil casing, more specifically, to a kind of steel for electric resistance welding (ERW) oil casing with low yield ratio A normalized steel, a low-yield-ratio electric resistance welded (ERW) oil casing made of the steel, and a method for making the casing. 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 K55 steel grade petroleum casing, seamless pipe and welded pipe. 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. But for K55 ERW casing, due to the high difficult...

Claims

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Application Information

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IPC IPC(8): C22C38/12C22C38/14E21B17/00B21B37/74C21D1/28C21D8/00C21D9/08B21D3/00
Inventor 田青超董晓明丁维军
Owner BAOSHAN IRON & STEEL CO LTD
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