High-performance P22 seamless steel tube forging material for pressure vessel and preparation method thereof

Abstract

The invention discloses a high-performance P22 seamless steel tube forging material for a pressure vessel. The high-performance P22 seamless steel tube forging material comprises the following components in percentage by mass: 0.08 to 0.15 percent of C (carbon), 2.00 to 2.20 percent of Cr (chromium), 0.95 to 1.25 percent of Mo (molybdenum), 0.07 to 0.13 percent of V (vanadium) and 0.60 to 0.75 percent of Mn (manganese). The invention further discloses a preparation method of the high-performance P22 seamless steel tube forged material for the pressure vessel, and the preparation method comprises the following steps that after molten steel is smelted in a converter, white slag is kept for 50-60 min; a steel ingot is prepared through a continuous casting process, and the pulling speed and specific water flow are controlled; the steel ingot is forged at the temperature of 1100-1200 DEG C; and the forged steel ingot is subjected to destressing treatment at the temperature of 670-690 DEG C. The toughness and plasticity of the material are improved, and the material is endowed with good thermal stability, so that the material can work for a long time in a high-temperature environment without losing performance.

Description

Technical Field

[0001] The present invention relates to the field of metallurgical technology, and particularly to a high-performance P22 seamless steel pipe forging material for pressure vessels and a preparation method thereof. Background Art

[0002] P22 steel is a widely used low-alloy high-strength steel with good thermal strength, corrosion resistance and weldability, and is suitable for manufacturing pressure vessels in high-temperature and high-pressure environments. However, the service performance of traditional 12Cr1MoV steel pipes still needs to be improved in some high-temperature, high-pressure and corrosive environments. Summary of the Invention

[0003] The purpose of the present invention is to provide a high-performance P22 seamless steel pipe forging material for pressure vessels and a preparation method thereof, which improve the toughness and plasticity of the material, endow it with good thermal stability, and enable it to work for a long time in a high-temperature environment without losing performance.

[0004] Technical Solution of the Present Invention:

[0005] A high-performance P22 seamless steel pipe forging material for pressure vessels, comprising the following components in mass percentage: carbon C: 0.08 - 0.15%, chromium Cr: 2.00 - 2.20%, molybdenum Mo: 0.95 - 1.25%, vanadium V: 0.07 - 0.13%, manganese Mn: 0.60 - 0.75%, and the balance is iron and its inevitable elements.

[0006] Preferably, it comprises the following components in mass percentage: carbon C: 0.11 - 0.14%, chromium Cr: 2.05 - 2.15%, molybdenum Mo: 1.10 - 1.20%, vanadium V: 0.10 - 0.12%, manganese Mn: 0.62 - 0.73%, and the balance is iron and its inevitable elements.

[0007] Preferably, a preparation method of a high-performance P22 seamless steel pipe forging material for pressure vessels comprises the following steps: after melting the molten steel in a converter, the white slag holding time is 50 - 60 min;

[0008] The steel ingot is prepared by continuous casting, and the drawing speed and specific water volume are controlled;

[0009] The steel ingot is forged at 1100 - 1200 °C;

[0010] The forged steel ingot is stress-relieved at 670 - 690 °C.

[0011] Preferably, the drawing speed is 0.25 - 0.28 m / min, and the specific water volume is 0.13 - 0.15 L / Kg.

[0012] Preferably, the deformation amount during forging is controlled at 30% - 50%.

[0013] Preferably, the holding time for stress relief treatment is 4 - 5 h / 100 mm.

[0014] Preferably, the flaw detection of the forged material product reaches Grade 4 of GB / T6402 - 2008.

[0015] Advantages of the present invention:

[0016] Through special smelting and heat treatment processes, white slag holding time and stress relief heat treatment, the present invention can obtain a fine and uniform grain structure, which helps to improve the toughness and plasticity of the material.

[0017] The optimized adjustment of the chromium, molybdenum and V elements contained in the material of the present invention endows it with good thermal stability, enabling it to work for a long time in a high-temperature environment without losing performance;

[0018] The present invention includes an innovative preparation method, special heat treatment with extended holding time and forging technology, which further improves the material performance. Specific embodiments

[0019] Example 1:

[0020] This forged material includes chemical composition design, forging and post-forging heat treatment, and the processes of each process are as described below:

[0021] 1. Chemical composition design

[0022] The internal control of carbon (C) is 0.08 - 0.10%, chromium (Cr) is 2.00 - 2.05%, molybdenum (Mo) is 0.95 - 1.05%, vanadium (V) is 0.07 - 0.09%, manganese (Mn) is 0.60 - 0.70%, and the balance is iron and its inevitable elements.

[0023] 2. After the molten steel is smelted in a converter, the white slag holding time is 50 min, and impurities are removed through secondary refining to improve the purity.

[0024] 3. The ingot is prepared by continuous casting process, controlling the casting speed at 0.25 m / min and the specific water volume at 0.13 L / Kg to obtain a uniform microstructure.

[0025] 4. The ingot is forged at 1100 °C, and the deformation amount is controlled at 30% to refine the grains.

[0026] 5. The forged ingot is subjected to stress relief treatment at 670 °C, and the holding time is 4 h / 100 mm to fully remove the stress generated during forging.

[0027] 6. After inspection, the flaw detection of the forged material product reaches Grade 4 of GB / T6402 - 2008.

[0028] 7. The mechanical property test data are shown in Table 1.

[0029] Table 1

[0030] Tensile strength Yield strength Elongation Impact energy AKV Standard 450-600 ≥280 ≥20 ≥35 Actual inspection 523 305 32 80

[0031] Example 2:

[0032] This forged material includes chemical composition design, forging, and post-forging heat treatment. The processes are as described below:

[0033] 1. Chemical composition design: The internal control of carbon (C) is 0.12 - 0.15%, chromium (Cr) is 2.10 - 2.20%, molybdenum (Mo) is 1.15 - 1.25%, vanadium (V) is 0.11 - 0.13%, manganese (Mn) is 0.65 - 0.75%, and the balance is iron and its inevitable elements.

[0034] 2. After the molten steel is smelted in the converter, the white slag holding time is 60 min, and impurities are removed through secondary refining to improve the purity.

[0035] 3. The ingot is prepared by continuous casting process, controlling the casting speed at 0.28 m / min and the specific water volume at 0.15 L / Kg to obtain a uniform microstructure.

[0036] 4. The ingot is forged at 1200 °C, and the deformation amount is controlled at 50% to refine the grains.

[0037] 5. The forged ingot is stress-relieved at 690 °C, and the holding time is 5 h / 100 mm to fully remove the stress generated during forging.

[0038] 6. After inspection, the flaw detection of the forged material product reaches Grade 4 of GB / T6402 - 2008.

[0039] 7. The mechanical property test data are shown in Table 2.

[0040] Table 2

[0041]

[0042] Example 3:

[0043] This forged material includes chemical composition design, forging, and post-forging heat treatment. The processes are as described below:

[0044] 1. Chemical composition design: The internal control of carbon (C) is 0.11 - 0.14%, chromium (Cr) is 2.05 - 2.15%, molybdenum (Mo) is 1.10 - 1.20%, vanadium (V) is 0.10 - 0.12%, manganese (Mn) is 0.62 - 0.73%, and the balance is iron and its inevitable elements.

[0045] 2. After the molten steel is smelted in the converter, the white slag holding time is 55 minutes, and impurities are removed through secondary refining to improve the purity.

[0046] 3. The ingot is prepared by continuous casting process, controlling the drawing speed at 0.27 m / min and the specific water volume at 0.14 L / Kg to obtain a uniform microstructure.

[0047] 4. The ingot is forged at 1150 °C with the deformation amount controlled at 40% to refine the grains.

[0048] 5. The forged ingot is stress-relieved at 680 °C with the holding time of 4.5 h / 100 mm to fully remove the stress generated during forging.

[0049] 6. After inspection, the flaw detection of the forged material product reaches Grade 4 of GB / T6402 - 2008.

[0050] 7. The mechanical property test data is shown in Table 3.

[0051] Table 3

[0052] Tensile strength Yield strength Elongation Impact energy AKV Standard 450-600 ≥280 ≥20 ≥35 Actual inspection 550 330 30 72

[0053] Example 4:

[0054] This forged material includes chemical composition design, forging and post-forging heat treatment, and the processes of each step are as described below:

[0055] 1. Chemical composition design: The internal control of carbon (C) is 0.11 - 0.14%, chromium (Cr) is 2.05 - 2.15%, molybdenum (Mo) is 1.10 - 1.20%, vanadium (V) is 0.10 - 0.12%, manganese (Mn) is 0.62 - 0.73%, and the balance is iron and its inevitable elements.

[0056] 2. After the molten steel is smelted in the converter, the white slag holding time is 53 minutes, and impurities are removed through secondary refining to improve the purity.

[0057] 3. The ingot is prepared by continuous casting process, controlling the drawing speed at 0.26 m / min and the specific water volume at 0.13 L / Kg to obtain a uniform microstructure.

[0058] 4. The ingot is forged at 1170 °C with the deformation amount controlled at 45% to refine the grains.

[0059] 5. The forged ingot is stress-relieved at 685 °C with the holding time of 4.5 h / 100 mm to fully remove the stress generated during forging.

[0060] 6. After inspection, the flaw detection of the forged material product reaches Grade 4 of GB / T6402 - 2008.

[0061] 7. The mechanical property test data are shown in Table 4.

[0062] Table 4

[0063] Tensile strength Yield strength Elongation Impact energy AKV Standard 450-600 ≥280 ≥20 ≥35 Actual inspection 545 328 32 70

[0064] After adopting the technology of the present invention, high-performance P22 seamless steel pipe forging materials that meet the requirements for pressure vessels have been successfully produced, meeting the requirements of high-end users.

[0065] Comparative Example 1:

[0066] This forging material includes chemical composition design, forging and post-forging heat treatment. The processes of each step are as described below:

[0067] 1. Chemical composition design

[0068] The internal control of carbon (C) is 0.08 - 0.10%, chromium (Cr) is 2.00 - 2.05%, molybdenum (Mo) is 0.95 - 1.05%, vanadium (V) is 0.07 - 0.09%, manganese (Mn) is 0.60 - 0.70%, and the balance is iron and its inevitable elements.

[0069] 2. After the molten steel is melted in the converter, the white slag holding time is 40 minutes, and impurities are removed through out-of-furnace refining to improve purity.

[0070] 3. The ingot is prepared by continuous casting process, controlling the drawing speed at 0.25 m / min and the specific water volume at 0.13 L / Kg to obtain a uniform microstructure.

[0071] 4. The ingot is forged at 1100 °C, and the deformation amount is controlled at 30% to refine the grains.

[0072] 5. The forged ingot is stress-relieved at 670 °C, and the holding time is 4 h / 100 mm to fully remove the stress generated during forging.

[0073] 6. After inspection, the flaw detection of the forging material product reaches Grade 4 of GB / T6402 - 2008.

[0074] 7. The mechanical property test data are shown in Table 5.

[0075] Table 5

[0076] Tensile strength Yield strength Elongation Impact energy AKV Standard 450-600 ≥280 ≥20 ≥35 Actual inspection 456 307 31 79

[0077] Comparative Example 2:

[0078] This forging material includes chemical composition design, forging and post-forging heat treatment. The processes of each step are as described below:

[0079] 1. Chemical composition design

[0080] The internal control of carbon (C) is 0.08 - 0.10%, chromium (Cr) is 2.00 - 2.05%, molybdenum (Mo) is 0.95 - 1.05%, vanadium (V) is 0.07 - 0.09%, manganese (Mn) is 0.60 - 0.70%, and the balance is iron and its inevitable elements.

[0081] 2. After the molten steel is smelted in the converter, the white slag holding time is 50 min, and impurities are removed through secondary refining to improve purity.

[0082] 3. The ingot is prepared by continuous casting process, controlling the casting speed at 0.25 m / min and the specific water volume at 0.13 L / Kg to obtain a uniform microstructure.

[0083] 4. The ingot is forged at 1100 °C, and the deformation amount is controlled at 30% to refine the grains.

[0084] 5. The forged ingot is stress-relieved at 670 °C, and the holding time is 3 h / 100 mm to remove the stress generated during forging.

[0085] 6. After inspection, the flaw detection of the forged material product reaches Grade 4 of GB / T6402 - 2008.

[0086] 7. The mechanical property test data are shown in Table 6.

[0087] Table 6

[0088] Tensile strength Yield strength Elongation Impact energy AKV Standard 450-600 ≥280 ≥20 ≥35 Actual inspection 440 278 30 75

[0089] If the stress is too high, white spot problems are likely to occur, resulting in microcracks in the product.

[0090] The above-described embodiments are only used to illustrate the technical ideas and features of the present invention, and the purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. It is not intended to limit the scope of the present invention. Equivalent changes and modifications made without departing from the concept and principle of the present invention still fall within the scope of the present invention patent.

Claims

1. A high-performance P22 seamless steel pipe forging material for pressure vessels, characterized in that, It comprises components with the following mass percentages: carbon C: 0.08 - 0.15%, chromium Cr: 2.00 - 2.20%, molybdenum Mo: 0.95 - 1.25%, vanadium V: 0.07 - 0.13%, manganese Mn: 0.60 - 0.75%, and the balance is iron and its inevitable elements.

2. The high-performance P22 seamless steel pipe forging material for pressure vessels according to claim 1, characterized in that, It comprises components with the following mass percentages: carbon C: 0.11 - 0.14%, chromium Cr: 2.05 - 2.15%, molybdenum Mo: 1.10 - 1.20%, vanadium V: 0.10 - 0.12%, manganese Mn: 0.62 - 0.73%, and the balance is iron and its inevitable elements.

3. The preparation method of a high-performance P22 seamless steel pipe forging material for a pressure vessel according to claim 1, characterized in that, It comprises the following steps: After the molten steel is smelted in a converter, the white slag holding time is 50 - 60 min; The ingot is prepared by continuous casting process, controlling the drawing speed and specific water volume; The ingot is forged at 1100 - 1200 °C; The forged ingot is stress relieved at 670 - 690 °C.

4. The preparation method of a high-performance P22 seamless steel pipe forging material for a pressure vessel according to claim 3, characterized in that, The drawing speed is 0.25 - 0.28 m / min, and the specific water volume is 0.13 - 0.15 L / Kg.

5. The preparation method of a high-performance P22 seamless steel pipe forging material for a pressure vessel according to claim 3, characterized in that, The deformation amount during forging is controlled at 30% - 50%.

6. The preparation method of a high-performance P22 seamless steel pipe forging material for a pressure vessel according to claim 3, characterized in that, The stress relief heat preservation time is 4 - 5 h / 100 mm.

7. The preparation method of a high-performance P22 seamless steel pipe forging material for a pressure vessel according to claim 3, characterized in that, The flaw detection of the forged material product reaches Grade 4 of GB / T6402 - 2008.

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