Seamless steel tube with hydrogen brittleness resistance for transporting hydrogen and manufacturing method of seamless steel tube

Abstract

The invention relates to an anti-hydrogen-brittleness seamless steel tube for hydrogen transportation and a manufacturing method thereof, and belongs to the technical field of seamless steel tubes, the anti-hydrogen-brittleness seamless steel tube for hydrogen transportation comprises the following chemical elements by mass percentage: 0.09-0.12% of C, 0.20-0.35% of Si, 1.05-1.15% of Mn, less than or equal to 0.020% of P, less than or equal to 0.0030% of S, less than or equal to 0.15% of Cu, less than or equal to 0.10% of Ni, less than or equal to 0.20% of Cr, less than or equal to 0.05% of Mo, less than or equal to 0.01% of V, less than or equal to 0.01% of Nb, less than or equal to 0.01% of Ti, less than or equal to 0.0005% of B, 0.020-0.035% of Through quenching and tempering processes, under the condition that the strength is guaranteed, the influence of a banded structure in the pipeline steel on hydrogen induced cracking is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of seamless steel pipes, and in particular, relates to a seamless steel pipe for hydrogen transport with hydrogen embrittlement resistance and a manufacturing method thereof. Background Art

[0002] As a zero-carbon and efficient new energy source, hydrogen energy will play an important role in the new global energy landscape and will become an important medium for the third energy revolution. In recent years, countries accounting for 80% of the world's GDP have introduced policies to strongly support the development of the hydrogen energy industry.

[0003] As a link and bridge between hydrogen production and use, hydrogen energy storage and transportation is crucial to the sustainable development of the entire hydrogen energy industry chain. Hydrogen energy storage and transportation will become an important factor restricting the large-scale development of the industry. Pipeline hydrogen transportation is the first choice for large-scale transportation in the future, and the cost of pipeline transportation is much lower than other methods. Therefore, special steels are urgently needed for hydrogen pipeline construction. The service conditions of gas pipelines are mostly humid environments, and the service environment contains more H2S and acidic substances. Corrosion is a key factor affecting the reliability and service life of pipeline systems, among which hydrogen embrittlement is one of the important forms of pipeline steel corrosion. The maximum service pressure is 10MPa, mainly providing hydrogen for the chemical or petroleum industry. The pipe body steel grade of these hydrogen pipelines usually does not exceed X52, so it is particularly important to develop X52QH hydrogen pipelines with hydrogen embrittlement resistance. Summary of the invention

[0004] The object of the present invention is to provide a seamless steel pipe for hydrogen transportation with resistance to hydrogen embrittlement and a manufacturing method thereof. By adopting medium and low carbon manganese steel and without adding additional alloy elements, the influence of the banded structure in the pipeline pipe steel on the resistance to hydrogen induced cracking is reduced while ensuring the strength, and the steel pipe can obtain a uniform tempered bainite structure after heat treatment, with a grain size of more than 9 levels, to ensure that the steel pipe has good resistance to hydrogen embrittlement.

[0005] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is as follows: a seamless steel pipe for hydrogen transport with resistance to hydrogen embrittlement, characterized in that it comprises the following chemical elements in percentage by mass: C: 0.09-0.12%, Si: 0.20-0.35%, Mn: 1.05-1.15%, P: ≤0.020%, S: ≤0.0030%, Cu: ≤0.15%, Ni: ≤0.10%, Cr: ≤0.20%, Mo: ≤0.05%, V: ≤0.01%, Nb: ≤0.01%, Ti: ≤0.01%, B: ≤0.0005%, Al: 0.020-0.035%, H: ≤1ppm, O: ≤15ppm, N: ≤40ppm.

[0006] As a further improvement of the above technical solution: A seamless steel pipe for hydrogen transport with resistance to hydrogen embrittlement also includes Ca. When the mass percentage of S is 0.0015-0.0030%, Ca≤0.004% and 2≤Ca / S≤5, and the balance is Fe and impurities.

[0007] As a further improvement of the above technical solution: A seamless steel pipe for hydrogen transport with resistance to hydrogen embrittlement also includes Ca. When the mass percentage of S is less than 0.0015%, Ca is less than or equal to 0.006%, and the remainder is Fe and impurities.

[0008] As a further improvement of the above technical solution: CE Pcm ≤0.18%.

[0009] As a further improvement of the above technical solution: The hydrogen embrittlement-resistant seamless steel pipe for hydrogen transportation has a yield strength of 360-480 MPa and a tensile strength of 460-600 MPa.

[0010] As a further improvement of the above technical solution: The hydrogen embrittlement-resistant seamless steel pipe for hydrogen transport has an elongation of ≥30%, a yield strength ratio of ≤0.8, a full-size transverse Charpy impact energy at -29°C of ≥100J, and an average shear area ratio of ≥85%.

[0011] As a further improvement of the above technical solution: The hardness of the hydrogen embrittlement-resistant seamless steel pipe for hydrogen transportation is ≤220HV10, and the grain size is ≥9.

[0012] As a further improvement of the above technical solution: A method for manufacturing a seamless steel pipe for hydrogen transport with resistance to hydrogen embrittlement, characterized in that it comprises the following steps: (1) Steelmaking: The converter smelting adopts double slag steelmaking, slag blocking steelmaking, ensuring low phosphorus in molten steel, and preventing pollution of molten steel and rephosphorization during steelmaking process; rapid dephosphorization at low temperature in the early stage, rapid decarburization, degassing and inclusion removal at high temperature in the later stage; power is supplied to heat up, melt the top slag, add deoxidizer for deoxidation, reduce the top slag to white foam slag, control the slag basicity to 2.6, and control the FeO content in the slag to 6%-10%. Then, the submerged arc heating argon blowing ladle refining method is adopted. In order to control the morphology of inclusions in the steel, calcium treatment should be carried out. After breaking the vacuum, silicon calcium wire or pure calcium wire is fed for strong deoxidation. The soft blowing time is greater than 8 minutes. Samples are taken to check the gas content and temperature, and then continuous casting is carried out; (2) Rolling: Ring furnace heating temperature: 1240~1280℃, piercing temperature: 1080~1120℃, rolling temperature: 980~1080℃, medium frequency heating furnace to control the final rolling temperature at 840~880℃, air cooling to room temperature on cooling bed, and sawing; (3) Heat treatment: The steel pipe is austenitized in a stepping furnace at a temperature of 910°C-950°C. The pipe is kept warm for ≥15 minutes depending on the wall thickness. The steel pipe is then quenched on a quenching machine with a rotating internal water spray and external water cooling. After cooling to room temperature, the steel pipe enters a tempering furnace for tempering at a temperature of 600°C-650°C. The pipe is kept warm for ≥30 minutes depending on the wall thickness. After exiting the furnace, the steel pipe is straightened at 400-500°C. The pipe is then air-cooled and inspected by an ultrasonic flaw detector.

[0013] The present invention adopts the above technical solution and has the following advantages: 1. The steel grade of the present invention is designed to control C to 0.12% or less, and Mn to 1.15% or less, without adding additional alloy elements. Through quenching and tempering processes, while ensuring strength, the influence of banded structure in pipeline pipe steel on hydrogen-induced cracking is reduced, and it is ensured that the steel pipe can obtain a uniform tempered troostite structure after heat treatment, and the grain size is above grade 9, so as to ensure that the steel pipe has good resistance to hydrogen embrittlement.

[0014] 2. When the hydrogen doping ratio increases from 0 to 30%, the tensile strength and elongation of the hydrogen embrittlement-resistant seamless steel pipe for hydrogen transportation of the present invention do not decrease.

[0015] 3. There are no cracks on the specimens in the hydrogen-induced cracking test and the four-point bending test.

[0016] The present invention will be further described below in conjunction with specific implementations and accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a diagram showing the dimensions of the tensile specimen in Test 4 of the present invention; Figure 2 The stress-strain curve of the pipe of the present invention in the test 4 of the present invention at a pressure of 10 MPa and a hydrogen doping ratio of 0 and 30%; Figure 3 This is the overall fracture diagram of the pipe of the present invention at a pressure of 10 MPa and a hydrogen mixing ratio of 0% in Test 4 of the present invention; Figure 4 This is the overall fracture diagram of the pipe of the present invention at a pressure of 10 MPa and a hydrogen mixing ratio of 30% in Test 4 of the present invention; Figure 5 This is a detailed view of the fracture of the pipe of the present invention at a pressure of 10 MPa and a hydrogen doping ratio of 30% in Test 4 of the present invention. DETAILED DESCRIPTION

[0018] The embodiments of the present invention are described in detail below with reference to the examples. In the examples, the specific conditions are not specified, and the experiments are carried out according to conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used without specifying the manufacturer are all conventional products that can be purchased on the market.

[0019] The described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. Example 1

[0020] A seamless steel pipe for hydrogen transport with resistance to hydrogen embrittlement, the mass percentages of chemical elements are: C: 0.09%, Si: 0.35%, Mn: 1.15%, P: 0.01%, S: 0.001%, Cu: 0.01%, Ni: 0.01%, Cr: 0.04%, Mo: 0.01%, V: 0.001%, Nb: 0.001%, Ti: 0.001%, B: 0.0001%, Al: 0.035%, Ca: 0.002%, H: 0.8ppm, O: 5ppm, N: 22ppm, CE Pcm : 0.16%, the balance is Fe and inevitable impurities.

[0021] A method for manufacturing a seamless steel pipe for hydrogen transport with resistance to hydrogen embrittlement comprises the following steps: (1) Steelmaking: The converter smelting adopts double slag steelmaking, slag blocking steelmaking, ensuring low phosphorus in molten steel, and preventing pollution of molten steel and rephosphorization during the steelmaking process. Rapid dephosphorization at low temperature in the early stage, rapid decarburization, degassing and inclusion removal at high temperature in the later stage. Power is supplied to heat up and melt the top slag, and deoxidize it by adding deoxidizer until the top slag is white foam slag. The slag basicity is controlled at 2.6, and the FeO mass percentage in the slag is controlled at 6%. Then, the submerged arc heating argon blowing ladle refining method is adopted. In order to control the morphology of inclusions in the steel, calcium treatment should be carried out. After breaking the vacuum, silicon calcium wire or pure calcium wire is fed for strong deoxidation. The soft blowing time is greater than 8 minutes. Samples are taken to check the gas content and temperature, and continuous casting is carried out.

[0022] (2) Rolling: Ring furnace heating temperature: 1240℃, piercing temperature: 1080℃, rolling temperature: 980℃, medium frequency heating furnace to control the final rolling temperature at 840℃, air cooling to room temperature on cooling bed, and sawing.

[0023] (3) Heat treatment: The steel pipe is austenitized in a stepping furnace at a temperature of 910°C. The heat preservation time is ≥15 minutes depending on the wall thickness. Then, the steel pipe is quenched and cooled on a quenching machine by a rotating internal water spraying and external water cooling method. After cooling to room temperature, the steel pipe enters a tempering furnace for tempering at a temperature of 600°C. The heat preservation time is ≥30 minutes depending on the wall thickness. After being taken out of the furnace, it is hot straightened at 400°C. Finally, it is air-cooled and inspected by an ultrasonic flaw detector. Example 2

[0024] A seamless steel pipe for hydrogen transport with resistance to hydrogen embrittlement, the mass percentages of chemical elements are: C: 0.10%, Si: 0.26%, Mn: 1.13%, P: 0.01%, S: 0.001%, Cu: 0.01%, Ni: 0.01%, Cr: 0.04%, Mo: 0.01%, V: 0.001%, Nb: 0.001%, Ti: 0.001%, B: 0.0001%, Al: 0.026%, Ca: 0.002%, H: 0.7ppm, O: 6ppm, N: 21ppm, CE Pcm : 0.17%, the balance is Fe and inevitable impurities.

[0025] A method for manufacturing a seamless steel pipe for hydrogen transport with resistance to hydrogen embrittlement comprises the following steps: (1) Steelmaking: The converter smelting adopts double slag steelmaking, slag blocking steelmaking, ensuring low phosphorus in molten steel, and preventing pollution of molten steel and rephosphorization during the steelmaking process. Rapid dephosphorization at low temperature in the early stage, rapid decarburization, degassing and inclusion removal at high temperature in the later stage. Power is supplied to heat up and melt the top slag, and deoxidize it by adding deoxidizer until the top slag is white foam slag. The slag basicity is controlled at 2.6, and the FeO mass percentage in the slag is controlled at 10%. Then, the submerged arc heating argon blowing ladle refining method is adopted. In order to control the morphology of inclusions in the steel, calcium treatment should be carried out. After breaking the vacuum, silicon calcium wire or pure calcium wire is fed for strong deoxidation. The soft blowing time is greater than 8 minutes. Samples are taken to check the gas content and temperature, and continuous casting is carried out.

[0026] (2) Rolling: Ring furnace heating temperature: 1280℃, piercing temperature: 1120℃, rolling temperature: 1080℃, medium frequency heating furnace to control the final rolling temperature at 880℃, air cooling to room temperature on cooling bed, and sawing.

[0027] (3) Heat treatment: The steel pipe is austenitized in a stepping furnace at 950°C and kept warm for ≥15 minutes depending on the wall thickness. Then, the steel pipe is quenched and cooled on a quenching machine by rotating internal water spraying and external water cooling. After cooling to room temperature, the steel pipe enters a tempering furnace for tempering at 650°C. The steel pipe is kept warm for ≥30 minutes depending on the wall thickness. After being taken out of the furnace, it is hot straightened at 500°C and finally air-cooled and inspected by an ultrasonic flaw detector. Example 3

[0028] A seamless steel pipe for hydrogen transport with resistance to hydrogen embrittlement, the mass percentages of chemical elements are: C: 0.12%, Si: 0.20%, Mn: 1.05%, P: 0.01%, S: 0.001%, Cu: 0.01%, Ni: 0.03%, Cr: 0.02%, Mo: 0.01%, V: 0.005%, Nb: 0.001%, Ti: 0.001%, B: 0.0001%, Al: 0.020%, Ca: 0.003%, H: 0.5ppm, O: 4ppm, N: 18ppm, CE Pcm : 0.18%, the balance is Fe and inevitable impurities.

[0029] A method for manufacturing a seamless steel pipe for hydrogen transport with resistance to hydrogen embrittlement comprises the following steps: (1) Steelmaking: The converter smelting adopts double slag steelmaking, slag blocking steelmaking, ensuring low phosphorus in molten steel, and preventing pollution of molten steel and rephosphorization during the steelmaking process. Rapid dephosphorization at low temperature in the early stage, rapid decarburization, degassing and inclusion removal at high temperature in the later stage. Power is supplied to heat up and melt the top slag, and deoxidize it by adding deoxidizer until the top slag is white foam slag. The slag basicity is controlled at 2.6, and the FeO mass percentage in the slag is controlled at 8%. Then, the submerged arc heating argon blowing ladle refining method is adopted. In order to control the morphology of inclusions in the steel, calcium treatment should be carried out. After breaking the vacuum, silicon calcium wire or pure calcium wire is fed for strong deoxidation. The soft blowing time is greater than 8 minutes. Samples are taken to check the gas content and temperature, and continuous casting is carried out.

[0030] (2) Rolling: Ring furnace heating temperature: 1260℃, piercing temperature: 1100℃, rolling temperature: 1030℃, medium frequency heating furnace to control the final rolling temperature at 860℃, air cooling to room temperature on cooling bed, and sawing.

[0031] (3) Heat treatment: The steel pipe is austenitized in a stepping furnace at 930°C and kept warm for ≥15 minutes depending on the wall thickness. Then, the steel pipe is quenched and cooled on a quenching machine by rotating internal water spraying and external water cooling. After cooling to room temperature, the steel pipe enters a tempering furnace for tempering at 625°C. The steel pipe is kept warm for ≥30 minutes depending on the wall thickness. After being taken out of the furnace, it is hot straightened at 450°C and finally air-cooled and inspected by an ultrasonic flaw detector.

[0032] test 1. The tensile test was carried out according to ASTM A370-24, the hardness test was carried out according to ASTM E18-24, the metallographic test was carried out according to ASTM E112-24, and the impact test was carried out according to ASTM A370-24 and ASTM A23-24. The results are shown in Table 1 below. The results meet the requirements of yield strength of 360-480MPa, tensile strength of 460-600MPa, elongation ≥30%, yield strength ratio ≤0.8, transverse full-size Charpy impact energy at -29℃ ≥100J, average shear area ratio ≥85%; hardness ≤220HV10; grain size ≥9 levels.

[0033] Table 1

[0034] 2. According to NACE TM0284, the hydrogen induced cracking test was carried out in solution A (environment). The results are shown in Table 2 below. The results show that the crack sensitivity rate (CSR), crack length rate (CLR), crack thickness rate (CTR), and crack area rate (CAR) are all 0.

[0035] Table 2

[0036] 3. A four-point bending test was carried out in solution A of NACE TM0177 according to ASTM G39. The specimen loading stress was 0.9 times the minimum yield strength of the steel pipe. The results are shown in Table 3. The results satisfy the requirement that no cracks appear on the tensile surface when observed at a magnification of 100 times.

[0037] Table 3

[0038] 4. According to GB / T 228.1-2021 Metal Material Tensile Test Part 1: Room Temperature Test Method, a high-pressure slow tensile test was carried out, and the tensile strength and elongation change curves under the conditions of 10 MPa concentration and 0 and 30% hydrogen doping ratio were compared to judge the hydrogen embrittlement resistance of the hydrogen transport seamless steel pipe with hydrogen embrittlement resistance of the present invention, as follows: (1) The size of the specimen is as follows: Figure 1 shown.

[0039] (2) Test results are as follows: Figure 2 As shown in the following Table 4, the results show that under a pressure of 10 MPa, when the hydrogen doping ratio increases from 0 to 30%, the tensile strength and elongation of the hydrogen embrittlement resistant seamless steel pipe for hydrogen transport of the present invention do not decrease, indicating that under this condition, the hydrogen embrittlement resistant seamless steel pipe for hydrogen transport of the present invention has good hydrogen embrittlement resistance.

[0040] Table 4

[0041] (3) Fracture image Figure 3-5 shown.

[0042] By observing the fracture surface, it can be found that under the conditions of pressure of 10MPa and hydrogen doping ratio of 0, the fracture surface is broken along 45° and the dimples are evenly distributed, showing obvious ductile fracture characteristics; when the hydrogen doping ratio is increased to 30%, multiple secondary cracks and a smooth fracture surface appear on the fracture surface, and the fracture is more obviously affected by hydrogen. It can be concluded that the increase in hydrogen content causes the cross section to show significant hydrogen-induced cracking characteristics.

[0043] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. The examples of the implementation methods and the parts not described in detail are common knowledge of ordinary technicians in the field. For those skilled in the art, they can still modify the technical solutions recorded in the above embodiments, or replace some of the technical features therein with equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A seamless steel pipe for hydrogen transport with resistance to hydrogen embrittlement, characterized in that: Including the following chemical elements in mass percentage: C: 0.09-0.12%, Si: 0.20-0.35%, Mn: 1.05-1.15%, P: ≤0.020%, S: ≤0.0030%, Cu: ≤0.15%, Ni: ≤0.10%, Cr: ≤0.20%, Mo: ≤0.05%, V: ≤0.01%, Nb: ≤0.01%, Ti: ≤0.01%, B: ≤0.0005%, Al: 0.020-0.035%, H: ≤1ppm, O: ≤15ppm, N: ≤40ppm.

2. The seamless steel pipe for hydrogen transport with hydrogen embrittlement resistance according to claim 1, characterized in that: It also includes Ca. When the S mass percentage is 0.0015-0.0030%, Ca≤0.004% and 2≤Ca / S≤5, the balance is Fe and impurities.

3. The seamless steel pipe for hydrogen transport with hydrogen embrittlement resistance according to claim 1, characterized in that: It also includes Ca. When the S mass percentage is ≤0.0015%, Ca is ≤0.006%, and the balance is Fe and impurities.

4. A seamless steel pipe for hydrogen transport with hydrogen embrittlement resistance according to claim 2 or 3, characterized in that: THIS Pcm ≤0.18%.

5. The seamless steel pipe for hydrogen transport with hydrogen embrittlement resistance according to claim 4, characterized in that: The hydrogen embrittlement-resistant seamless steel pipe for hydrogen transportation has a yield strength of 360-480 MPa and a tensile strength of 460-600 MPa.

6. The seamless steel pipe for hydrogen transport with hydrogen embrittlement resistance according to claim 5, characterized in that: The hydrogen embrittlement-resistant seamless steel pipe for hydrogen transport has an elongation of ≥30%, a yield strength ratio of ≤0.8, a full-size transverse Charpy impact energy at -29°C of ≥100J, and an average shear area ratio of ≥85%.

7. The seamless steel pipe for hydrogen transport with hydrogen embrittlement resistance according to claim 6, characterized in that: The hardness of the hydrogen embrittlement-resistant seamless steel pipe for hydrogen transportation is ≤220HV10, and the grain size is ≥9 grades.

8. A method for manufacturing a seamless steel pipe for hydrogen transport with resistance to hydrogen embrittlement, characterized in that: The steps include: (1) Steelmaking: The converter smelting adopts double slag steelmaking, slag blocking steelmaking, ensuring low phosphorus in molten steel, and preventing pollution of molten steel and rephosphorization during steelmaking process; rapid dephosphorization at low temperature in the early stage, rapid decarburization, degassing and inclusion removal at high temperature in the later stage; power is supplied to heat up, melt the top slag, add deoxidizer for deoxidation, reduce the top slag to white foam slag, control the slag basicity to 2.6, and control the FeO mass percentage in the slag to 6%-10%. Then, the submerged arc heating argon blowing ladle refining method is adopted. In order to control the morphology of inclusions in the steel, calcium treatment should be carried out. After breaking the vacuum, silicon calcium wire or pure calcium wire is fed for strong deoxidation. The soft blowing time is greater than 8 minutes. Samples are taken to check the gas content and temperature, and then continuous casting is carried out; (2) Rolling: Ring furnace heating temperature: 1240~1280℃, piercing temperature: 1080~1120℃, rolling temperature: 980~1080℃, medium frequency heating furnace to control the final rolling temperature at 840~880℃, air cooling to room temperature on cooling bed, and sawing; (3) Heat treatment: The steel pipe is austenitized in a stepping furnace at a temperature of 910°C-950°C. The pipe is kept warm for ≥15 minutes depending on the wall thickness. The steel pipe is then quenched on a quenching machine with a rotating internal water spray and external water cooling. After cooling to room temperature, the steel pipe enters a tempering furnace for tempering at a temperature of 600°C-650°C. The pipe is kept warm for ≥30 minutes depending on the wall thickness. After exiting the furnace, the steel pipe is straightened at 400-500°C. The pipe is then air-cooled and inspected by an ultrasonic flaw detector.

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