Steel pipe for petroleum pipeline and preparation method thereof

Abstract

The present application discloses a steel pipe for oil pipeline and a preparation method thereof; it relates to the technical field of oil pipeline; the steel pipe of the present application is prepared from the following components by weight percentage: C: 0.12-0.15%; Si: 0.20-0.30%; Mn: 0.80-1.00%; Cu: 0.10-0.15%; Cr: 0.50-0.80%; Ni: 0.10-0.15%; Mo: 0.10-0.15%; V: 0.02-0.03%; Al: ≤0.02%; Fe balance. The preparation method includes S1, smelting and refining; S2, continuous casting; S3, rolling processing; S4, heat treatment; S5, post-processing and testing. The present invention improves the corrosion resistance of the steel pipe by adding Cu, Cr, Ni and Mo; refines the grains by adding V to improve the strength and toughness of the steel pipe; and makes the steel pipe prepared by the present application more suitable for oil pipelines.

Description

Technical Field

[0001] The present application relates to the technical field of oil pipelines, and in particular to a steel pipe for oil pipelines and a preparation method thereof. Background Art

[0002] In recent years, with the exploitation and transportation of oil and gas in geologically unstable areas and deep seas, as well as long-distance high-pressure oil and gas transportation on land, the development of high-pressure and high-deformation-resistant pipeline steel has become a hot topic for various manufacturers. At present, oil and gas pipelines are developing towards high performance and long life.

[0003] At present, some steel pipes used in oil pipelines have an organic corrosion-resistant layer added to the inner and outer layers. The preparation process is relatively complicated and the cost is increased. How to improve the mechanical properties and corrosion resistance of steel pipes by improving the materials used in steel pipes is a problem that needs to be solved at present. Summary of the invention

[0004] In order to solve at least one of the above technical problems and develop a steel pipe with good mechanical properties and strong corrosion resistance, the present application provides a steel pipe for oil pipelines and a preparation method thereof.

[0005] On the one hand, the present application provides a steel pipe for petroleum pipeline, which is prepared from the following components by weight percentage:

[0006] C: 0.12~0.15%;

[0007] Si: 0.20-0.30%;

[0008] Mn: 0.80~1.00%;

[0009] Cu: 0.10~0.15%;

[0010] Cr: 0.50~0.80%;

[0011] Ni: 0.10~0.15%;

[0012] Mo: 0.10~0.15%;

[0013] V: 0.02~0.03%;

[0014] Al: ≤0.02%;

[0015] Fe balance.

[0016] By adopting the above technical solution, the prepared steel pipe has high strength, good toughness, strong corrosion resistance and good welding performance, and is suitable for oil pipelines.

[0017] Optionally, the weight ratio of Cu, Cr, Ni, and Mo is (0.22-0.25):1:(0.22-0.25):(0.22-0.25).

[0018] By adopting the above technical solution, the corrosion resistance of the pipeline is further improved, so that the steel pipe is not easily corroded when used in the oil pipeline.

[0019] Optional, wherein P: ≤0.01%; S: ≤0.01%.

[0020] By adopting the above technical solution, the phosphorus and sulfur contents in the steel pipe can be controlled, the toughness of the steel pipe can be improved, and the welding defects of the steel pipe can be reduced.

[0021] In a second aspect, the present application provides a method for preparing the above-mentioned steel pipe for petroleum pipeline, comprising the following steps:

[0022] S1. Smelting and refining

[0023] The iron ore / scrap is smelted and then refined to remove impurities;

[0024] S2, continuous casting

[0025] The refined molten steel is poured into a continuous casting machine to form a tubular billet;

[0026] S3. Rolling processing

[0027] The tubular billet prepared in S2 is rolled to obtain a seamless steel pipe;

[0028] S4. Heat treatment

[0029] The seamless steel pipe prepared in S3 is heat treated, including normalizing, quenching and tempering steps in sequence;

[0030] S5. Post-processing and testing

[0031] The heat-treated steel pipe is subsequently processed according to the application requirements and tested. After passing the test, the steel pipe for oil pipeline is obtained.

[0032] Optionally, in S2, continuous casting, the temperature of the first continuous casting furnace is: 1590±5℃, the second furnace: 1560±5℃, and the third and subsequent furnaces: 1550±5℃.

[0033] Optionally, in S2, during continuous casting, the superheat of the package is controlled at 20-30°C during the casting process.

[0034] Optionally, in S3, during the rolling process, the starting rolling temperature is 1120°C to 1180°C; the final rolling temperature is ensured to be 920°C to 1020°C; the specification of the rolled round bar is Φ280mm, and the compression ratio is ≥4.

[0035] Optional, S4, heat treatment, normalizing: heating to 670±10℃, keeping warm, and air cooling;

[0036] And / or, quenching: heating to 660±20℃ and keeping warm, then quenching with water or polymer;

[0037] And / or, Tempering: Heat to 680±30℃ and keep warm, then air cool.

[0038] In summary, the present invention includes at least one of the following beneficial technical effects:

[0039] 1. The corrosion resistance of the steel pipe is improved by adding Cu, Cr, Ni, and Mo, so that the steel pipe prepared in this application can be better suitable for oil pipelines;

[0040] 2. By adding V to refine the grains, the strength and toughness of the steel pipe are improved; so that the steel pipe prepared in this application can be better suitable for oil pipelines. DETAILED DESCRIPTION

[0041] The present application is further described in detail below in conjunction with embodiments.

[0042] In the following examples of the present application, the main components involved, unless otherwise specified, were purchased from commercially available products. Specific embodiments

[0044] Example 1

[0045] This embodiment is used to prepare a steel pipe for a petroleum pipeline, and the details are as follows.

[0046] S1. Smelting and refining

[0047] The iron ore / scrap is smelted to obtain pig iron in a blast furnace, and then refined in an electric arc furnace to remove impurities and adjust the chemical composition to the required specifications, specifically C: 0.12%; Si: 0.30%; Mn: 0.80%; Cu: 0.10%; Cr: 0.80%; Ni: 0.10%; Mo: 0.10%; V: 0.02%; Al: 0.02%; P: 0.01%; S: 0.01%; Fe balance.

[0048] The refined molten steel is poured into a continuous casting machine to form a tubular billet; the temperature of the first continuous casting furnace is: 1590±5℃, the second furnace: 1560±5℃, and the third and subsequent furnaces: 1550±5℃.

[0049] The tubular billet is rolled at a starting rolling temperature of 1120°C to 1180°C; the final rolling temperature is ensured to be 920°C to 1020°C; the specification of the rolled round bar is Φ280mm, and the compression ratio is ≥4; and a seamless steel pipe is obtained.

[0050] The seamless steel pipe prepared in S3 is heat treated as follows: normalizing: heating to 670±10°C, keeping warm, and then air cooling; quenching: heating to 660±20°C, keeping warm, and then water or polymer quenching; tempering: heating to 680±30°C, keeping warm, and then air cooling.

[0051] The heat-treated steel pipe is subsequently processed according to the application requirements and tested. The test results are shown in Table 1.

[0052] Example 2

[0053] This embodiment is used to prepare a steel pipe for a petroleum pipeline, and the details are as follows.

[0054] S1. Smelting and refining

[0055] The iron ore / scrap is smelted to obtain pig iron in a blast furnace, and then refined in an electric arc furnace to remove impurities and adjust the chemical composition to the required specifications, specifically C: 0.15%; Si: 0.25%; Mn: 0.90%; Cu: 0.11%; Cr: 0.70%; Ni: 0.11%; Mo: 0.11%; V: 0.03%; Al: 0.02%; P: 0.01%; S: 0.01%; Fe balance.

[0056] The refined molten steel is poured into a continuous casting machine to form a tubular billet; the temperature of the first continuous casting furnace is: 1590±5℃, the second furnace: 1560±5℃, and the third and subsequent furnaces: 1550±5℃.

[0057] The tubular billet is rolled at a starting rolling temperature of 1120°C to 1180°C; the final rolling temperature is ensured to be 920°C to 1020°C; the specification of the rolled round bar is Φ280mm, and the compression ratio is ≥4; and a seamless steel pipe is obtained.

[0058] The seamless steel pipe prepared in S3 is heat treated as follows: normalizing: heating to 670±10°C, keeping warm, and then air cooling; quenching: heating to 660±20°C, keeping warm, and then water or polymer quenching; tempering: heating to 680±30°C, keeping warm, and then air cooling.

[0059] The heat-treated steel pipe is subsequently processed according to the application requirements and tested. The test results are shown in Table 1.

[0060] Example 3

[0061] This embodiment is used to prepare a steel pipe for a petroleum pipeline, and the details are as follows.

[0062] S1. Smelting and refining

[0063] The iron ore / scrap is smelted to obtain pig iron in a blast furnace, and then refined in an electric arc furnace to remove impurities and adjust the chemical composition to the required specifications, specifically C: 0.12%; Si: 0.20%; Mn: 1.00%; Cu: 0.12%; Cr: 0.65%; Ni: 0.12%; Mo: 0.12%; V: 0.02%; Al: 0.02%; P: 0.01%; S: 0.01%; Fe balance.

[0064] The refined molten steel is poured into a continuous casting machine to form a tubular billet; the temperature of the first continuous casting furnace is: 1590±5℃, the second furnace: 1560±5℃, and the third and subsequent furnaces: 1550±5℃.

[0065] The tubular billet is rolled at a starting rolling temperature of 1120°C to 1180°C; the final rolling temperature is ensured to be 920°C to 1020°C; the specification of the rolled round bar is Φ280mm, and the compression ratio is ≥4; and a seamless steel pipe is obtained.

[0066] The seamless steel pipe prepared in S3 is heat treated as follows: normalizing: heating to 670±10°C, keeping warm, and then air cooling; quenching: heating to 660±20°C, keeping warm, and then water or polymer quenching; tempering: heating to 680±30°C, keeping warm, and then air cooling.

[0067] The heat-treated steel pipe is subsequently processed according to the application requirements and tested. The test results are shown in Table 1.

[0068] Example 4

[0069] This embodiment is used to prepare a steel pipe for a petroleum pipeline, and the details are as follows.

[0070] S1. Smelting and refining

[0071] The iron ore / scrap is smelted to obtain pig iron in a blast furnace, and then refined in an electric arc furnace to remove impurities and adjust the chemical composition to the required specifications, specifically C: 0.15%; Si: 0.30%; Mn: 0.80%; Cu: 0.13%; Cr: 0.60%; Ni: 0.13%; Mo: 0.13%; V: 0.03%; Al: 0.02%; P: 0.01%; S: 0.01%; Fe balance.

[0072] The refined molten steel is poured into a continuous casting machine to form a tubular billet; the temperature of the first continuous casting furnace is: 1590±5℃, the second furnace: 1560±5℃, and the third and subsequent furnaces: 1550±5℃.

[0073] The tubular billet is rolled at a starting rolling temperature of 1120°C to 1180°C; the final rolling temperature is ensured to be 920°C to 1020°C; the specification of the rolled round bar is Φ280mm, and the compression ratio is ≥4; and a seamless steel pipe is obtained.

[0074] The seamless steel pipe prepared in S3 is heat treated as follows: normalizing: heating to 670±10°C, keeping warm, and then air cooling; quenching: heating to 660±20°C, keeping warm, and then water or polymer quenching; tempering: heating to 680±30°C, keeping warm, and then air cooling.

[0075] The heat-treated steel pipe is subsequently processed according to the application requirements and tested. The test results are shown in Table 1.

[0076] Example 5

[0077] This embodiment is used to prepare a steel pipe for a petroleum pipeline, and the details are as follows.

[0078] S1. Smelting and refining

[0079] The iron ore / scrap is smelted to obtain pig iron in a blast furnace, and then refined in an electric arc furnace to remove impurities and adjust the chemical composition to the required specifications, specifically C: 0.12%; Si: 0.25%; Mn: 0.90%; Cu: 0.14%; Cr: 0.55%; Ni: 0.14%; Mo: 0.14%; V: 0.02%; Al: 0.02%; P: 0.01%; S: 0.01%; Fe balance.

[0080] The refined molten steel is poured into a continuous casting machine to form a tubular billet; the temperature of the first continuous casting furnace is: 1590±5℃, the second furnace: 1560±5℃, and the third and subsequent furnaces: 1550±5℃.

[0081] The tubular billet is rolled at a starting rolling temperature of 1120°C to 1180°C; the final rolling temperature is ensured to be 920°C to 1020°C; the specification of the rolled round bar is Φ280mm, and the compression ratio is ≥4; and a seamless steel pipe is obtained.

[0082] The seamless steel pipe prepared in S3 is heat treated as follows: normalizing: heating to 670±10°C, keeping warm, and then air cooling; quenching: heating to 660±20°C, keeping warm, and then water or polymer quenching; tempering: heating to 680±30°C, keeping warm, and then air cooling.

[0083] The heat-treated steel pipe is subsequently processed according to the application requirements and tested. The test results are shown in Table 1.

[0084] Example 6

[0085] This embodiment is used to prepare a steel pipe for a petroleum pipeline, and the details are as follows.

[0086] S1. Smelting and refining

[0087] The iron ore / scrap is smelted to obtain pig iron in a blast furnace, and then refined in an electric arc furnace to remove impurities and adjust the chemical composition to the required specifications, specifically C: 0.15%; Si: 0.20%; Mn: 1.00%; Cu: 0.15%; Cr: 0.50%; Ni: 0.15%; Mo: 0.15%; V: 0.03%; Al: 0.02%; P: 0.01%; S: 0.01%; Fe balance.

[0088] The refined molten steel is poured into a continuous casting machine to form a tubular billet; the temperature of the first continuous casting furnace is: 1590±5℃, the second furnace: 1560±5℃, and the third and subsequent furnaces: 1550±5℃.

[0089] The tubular billet is rolled at a starting rolling temperature of 1120°C to 1180°C; the final rolling temperature is ensured to be 920°C to 1020°C; the specification of the rolled round bar is Φ280mm, and the compression ratio is ≥4; and a seamless steel pipe is obtained.

[0090] The seamless steel pipe prepared in S3 is heat treated as follows: normalizing: heating to 670±10°C, keeping warm, and then air cooling; quenching: heating to 660±20°C, keeping warm, and then water or polymer quenching; tempering: heating to 680±30°C, keeping warm, and then air cooling.

[0091] The heat-treated steel pipe is subsequently processed according to the application requirements and tested. The test results are shown in Table 1.

[0092] According to the NACETM0177-2005 standard, the A method standard tensile test was carried out. The test solution was a saturated H2S solution A containing 5% NaCl and 0.5% CH3COOH, with a pH value of about 2.7, and the standard test time was 720 hours.

[0093] Table 1

[0094]

[0095]

[0096] It can be seen from Examples 1 to 6 and Table 1 that the tensile strength of the steel pipe prepared by the technical solution of the present application can reach more than 800 MPa, the yield strength can reach more than 630 MPa, the elongation after fracture is between 19% and 21%, the SSC resistance can reach 120h without cracking, and the HIC resistance can reach less than 0.40. It can be seen that the steel pipe prepared by the present application has good mechanical properties and strong corrosion resistance, and can be well applied to oil pipelines.

[0097] Further analysis of Table 1 shows that when the weight ratio of Cu:Cr:N:Mo is (0.22~0.25):1:(0.22~0.25):(0.22~0.25), the mechanical properties of the prepared steel pipe are better and the corrosion resistance is further improved. Therefore, it can be seen that adjusting the weight ratio of Cu:Cr:N:Mo in the technical solution of the present application can further improve the corrosion resistance of the steel pipe.

[0098] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A steel pipe for petroleum pipeline, characterized in that: Prepared from the following components by weight percentage: C：0.12～0.15％； Si: 0.20-0.30%; Mn: 0.80~1.00%; Cu: 0.10~0.15%; Cr：0.50～0.80％； Ni: 0.10~0.15%; Mo: 0.10~0.15%; V：0.02～0.03％； Al：≤0.02％； Fe balance.

2. The steel pipe for petroleum pipeline according to claim 1, characterized in that: The weight ratio of Cu, Cr, Ni and Mo is (0.22-0.25):1:(0.22-0.25):(0.22-0.25).

3. The steel pipe for petroleum pipeline according to claim 1, characterized in that: Among them, P: ≤0.01%; S: ≤0.01%.

4. A method for preparing a steel pipe for a petroleum pipeline according to claim 1, characterized in that: The following steps are involved: S1. Smelting and refining The iron ore / scrap is smelted and then refined to remove impurities; S2, continuous casting The refined molten steel is poured into a continuous casting machine to form a tubular billet; S3. Rolling processing The tubular billet prepared in S2 is rolled to obtain a seamless steel pipe; S4. Heat treatment The seamless steel pipe prepared in S3 is heat treated, including normalizing, quenching and tempering steps in sequence; S5. Post-processing and testing The heat-treated steel pipe is subsequently processed according to the application requirements and tested. After passing the test, the steel pipe for oil pipeline is obtained.

5. The preparation method according to claim 1, characterized in that: In the continuous casting process S2, the temperature of the first continuous casting furnace is 1590±5°C, the temperature of the second continuous casting furnace is 1560±5°C, and the temperature of the third continuous casting furnace and the subsequent continuous casting furnaces is 1550±5°C.

6. The preparation method according to claim 1, characterized in that: In the above-mentioned S2, in the continuous casting, the superheat of the package is controlled at 20-30°C during the casting process.

7. The preparation method according to claim 1, characterized in that: In the S3 rolling process, the starting rolling temperature is 1120° C. to 1180° C.; the final rolling temperature is ensured to be 920° C. to 1020° C.; the specification of the rolled round bar is Φ280 mm, and the compression ratio is ≥4.

8. The preparation method according to claim 1, characterized in that: In the heat treatment of S4, normalizing: heating to 670±10℃, keeping warm, and then air cooling; And / or, quenching: heating to 660±20℃ and keeping warm, then quenching with water or polymer; And / or, Tempering: Heat to 680±30℃, keep warm and then air cool.

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