A seamless steel pipe for hydrogen transportation in submarine service and its preparation method

Abstract

The present invention relates to a seamless steel pipe for hydrogen transportation in submarine service, wherein the chemical elements have the following mass percentages: C: 0.08% to 0.14%; Si: 0.20% to 0.40%; Mn: 0.80% to 1.35%; P: ≤0.015%; S: ≤0.003%; Ni: ≤0.10%; Cr: 0.08% to 0.20%; Mo: ≤0.10%; Cu: ≤0.15%; N b: 0.01%~0.04%; V: 0.01%~0.04%; Ti: 0.01%~0.04%; Al: 0.015%~0.045%; N: 0.003%~0.010%; B: ≤0.0005%; H: ≤0.0001%; ​​the rest is Fe and impurities; the present invention has low manufacturing cost, high yield rate, excellent mechanical properties, excellent hydrogen corrosion resistance and seawater corrosion resistance.

Description

Technical Field

[0001] The invention belongs to the technical field of seamless steel pipe manufacturing, and in particular relates to a seamless steel pipe for submarine hydrogen transportation and a preparation method thereof. Background Art

[0002] Hydrogen is the lightest gas, colorless, odorless, volatile, and has an explosion limit of 4.1% to 75.0% (volume) in the air. Water is the only combustion product. Under heating or in the presence of a catalyst, hydrogen is very active and can easily react chemically with a variety of substances. Hydrogen energy is a typical clean energy source that is pollution-free, has a high calorific value, and is rich in resources. It is regarded as the clean energy source with the greatest development potential in the 21st century and can be widely used in many fields such as chemical industry, machinery, electronics, light industry, aviation, etc. Hydrogen fuel cells and hydrogen-powered vehicles are receiving more and more attention from countries.

[0003] For hydrogen energy to be widely used, it is necessary to complete large-scale, long-distance hydrogen transportation. Hydrogen has a wide explosion limit, is flammable and explosive, and is a dangerous product. Safe and reliable technology and equipment must be used. Continuous and large-scale hydrogen transportation mainly adopts long-distance pipeline transportation. Hydrogen pipelines can transport hydrogen with a purity of 99.5%. Compared with road transportation, the use of pipelines will greatly reduce the operating costs of enterprises, and has obvious advantages in economy and environmental protection.

[0004] Hydrogen has the characteristics of corrosiveness, hydrogen embrittlement and hydrogen-induced cracking. Hydrogen embrittlement is sensitive to the strength of steel. The higher the steel grade strength, the more likely it is to have hydrogen embrittlement. In addition to requiring corresponding strength, impact resistance and welding performance, seamless steel pipes for hydrogen transportation are also required to have the ability to resist hydrogen damage. At present, there is still a blank in the domestic design technology for pipes used in long-distance hydrogen pipelines. They are all designed with reference to natural gas pipelines or industrial pipelines. Low-pressure transportation mostly uses 20 and 15CrMo steel grades, which have the risk of hydrogen embrittlement and hydrogen-induced cracking. Regarding hydrogen transportation line pipes, especially those suitable for submarine transportation, there is also a lack of relevant professional discussions on the composition design, manufacturing methods, quality inspection and other aspects of line pipes. Summary of the invention

[0005] The purpose of the present invention is to provide an economical seamless steel pipe for submarine hydrogen transportation; the second purpose is to provide a method for manufacturing a seamless steel pipe for submarine hydrogen transportation; it is beneficial to provide a safe and reliable pipeline for long-distance transportation of hydrogen and solve the corrosion problem in the process of hydrogen transportation; the pipeline pipe has a simple alloy component system, low manufacturing cost, high yield rate, excellent mechanical properties, and excellent hydrogen corrosion resistance and seawater corrosion resistance.

[0006] The present invention solves the technical problem by adopting the following technical solutions:

[0007] A seamless steel pipe for submarine hydrogen transportation, wherein the mass percentages of chemical elements in the seamless steel pipe are respectively:

[0008] C: 0.08% ~ 0.14%; Si: 0.20% ~ 0.40%; Mn: 0.80% ~ 1.35%; P: ≤ 0.015%;

[0009] S: ≤0.003%; Ni: ≤0.10%; Cr: 0.08%~0.20%; Mo: ≤0.10%; Cu: ≤0.15%; Nb: 0.01%~0.04%; V: 0.01%~0.04%; Ti: 0.01%~0.04%; Al: 0.015%~0.045%; N: 0.003%~0.010%; B: ≤0.0005%; H: ≤0.0001%; ​​the rest are Fe and unavoidable impurities, carbon equivalent CEIIW ≤0.34%, CEpcm ≤0.22%.

[0010] A method for preparing a seamless steel pipe for submarine hydrogen transportation comprises the following steps:

[0011] Steelmaking process: EAF electric furnace, LF refining furnace, VD vacuum furnace, CCM continuous casting to obtain tube billets; high-quality scrap steel, sponge iron and molten iron are used as raw materials, and the proportion of molten iron added is not less than 40%; argon is blown throughout the refining process, and secondary slag desulfurization is performed; VD treatment time ≥18min, high vacuum time ≥10min, working vacuum degree ≤0.5Torr; 80m~150m of Ca-Si wire is fed before continuous casting, and the molten steel is weakly stirred for ≥4min after feeding the wire; the straightening temperature of the continuous casting secondary cooling zone is ≥930℃, electromagnetic stirring is performed at the end of continuous casting, and the continuous casting billet is put into a pit for slow cooling and stacking for ≥24 hours after cutting;

[0012] Pipe rolling process: After the tube is sawed, centering holes of φ30mm~50m are punched at both ends. The tube is heated in a ring heating furnace with a furnace temperature of 1240℃~1290℃, two-roller oblique hot piercing at 1200℃~1250℃, PQF continuous rolling unit continuous rolling temperature of 1050℃~1220℃, 12-stand three-roller sizing temperature of 830℃~910℃, cooled on a cooling bed, and sawed; the outer diameter control accuracy of the steel pipe is ±0.50%D, and the wall thickness control accuracy is ±8%t;

[0013] Heat treatment process: The steel pipe is heated to 890℃~960℃ in a walking-beam high-temperature heating furnace, kept warm for 15~30min, then immersed in a rotary internal spray and external shower quenching, heated to 580℃~680℃ in a walking-beam low-temperature heating furnace, kept warm for 15~30min, and tempered; 500℃~600℃ high-temperature sizing and straightening are adopted, and the straightness is less than 0.12%L, and the out-of-roundness is less than 0.8%D;

[0014] Processing technology: non-destructive testing, longitudinal and transverse inspection of internal and external surfaces, inspection level U2 / C; hydrostatic test. Water pressure coefficient 0.90%, pressure maintenance 10s; inner surface shot peening, pipe end processing groove, pipe end with protective ring, steel pipe spraying, painting.

[0015] Furthermore, the mechanical properties of the seamless pipeline reach: yield strength 290Mpa~395Mpa, yield strength fluctuation range ≤90MPa, tensile strength 415Mpa~535Mpa, tensile strength fluctuation range ≤110Mpa, yield strength ratio: ≤0.80, elongation ≥35%, 0℃ transverse full-size Charpy impact energy ≥280J, hardness: ≤180HV10, metallographic structure: duplex structure F+B back, grain size 9.0 and above, banded structure ≤2.0, the sum of four types of inclusions A, B, C, and D ≤2.

[0016] The advantages and positive effects of the present invention are:

[0017] 1) The present invention has low carbon, low manganese and low carbon equivalent, adds appropriate amounts of V, Nb, Ti and Al alloys, controls phosphorus and sulfur content, spheroidizes silicon-calcium wire inclusions, and continuously casts electromagnetic stirring, so that the pipeline steel has uniform chemical composition and low content of harmful elements;

[0018] 2) The PQF continuous rolling method of the present invention obtains a tube body with high dimensional accuracy, with the outer diameter control accuracy of the steel tube being ±0.50%D and the wall thickness control accuracy being ±8%t;

[0019] 3) The quenching and tempering process of the present invention ensures that the steel pipe has excellent final mechanical properties, uniform and fine structure, and excellent welding performance, meeting the use requirements of submarine hydrogen transmission pipeline pipes. DETAILED DESCRIPTION

[0020] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application may be combined with each other.

[0021] Example 1

[0022] A seamless steel pipe for submarine hydrogen transportation, wherein the mass percentages of chemical elements in the seamless steel pipe are respectively:

[0023] C: 0.08% ~ 0.14%; Si: 0.20% ~ 0.40%; Mn: 0.80% ~ 1.35%; P: ≤ 0.015%; S: ≤ 0.003%; Ni: ≤ 0.10%; Cr: 0.08% ~ 0.20%; Mo: ≤ 0.10%; Cu: ≤ 0.15%; Nb: 0.01% ~ 0.04%; V: 0.01% ~ 0.04%; Ti: 0.01% ~ 0.04%; Als: 0.015% ~ 0.045%; N: 0.003% ~ 0.010%; B: ≤ 0.0005%; H: ≤ 0.0001%; ​​the rest is Fe and unavoidable impurities, carbon equivalent CE IIW ≤0.34%, CEpcm≤0.22%.

[0024] A method for preparing a seamless steel pipe for submarine hydrogen transportation comprises the following steps:

[0025] Steelmaking process: EAF electric furnace, LF refining furnace, VD vacuum furnace, CCM continuous casting to obtain tube billets; high-quality scrap steel, sponge iron and molten iron are used as raw materials, and the proportion of molten iron added is not less than 40%; argon is blown throughout the refining process, and secondary slag desulfurization is performed; VD treatment time ≥18min, high vacuum time ≥10min, working vacuum degree ≤0.5Torr; 80m~150m of Ca-Si wire is fed before continuous casting, and the molten steel is weakly stirred for ≥4min after feeding the wire; the straightening temperature of the continuous casting secondary cooling zone is ≥930℃, electromagnetic stirring is performed at the end of continuous casting, and the continuous casting billet is put into a pit for slow cooling and stacking for ≥24 hours after cutting;

[0026] Pipe rolling process: After the tube is sawed, centering holes of φ30mm~50m are punched at both ends. The tube is heated in a ring heating furnace with a furnace temperature of 1240℃~1290℃, two-roller oblique hot piercing at 1200℃~1250℃, PQF continuous rolling unit continuous rolling temperature of 1050℃~1220℃, 12-stand three-roller sizing temperature of 830℃~910℃, cooled on a cooling bed, and sawed; the outer diameter control accuracy of the steel pipe is ±0.50%D, and the wall thickness control accuracy is ±8%t;

[0027] Heat treatment process: The steel pipe is heated to 890℃~960℃ in a walking-beam high-temperature heating furnace, kept warm for 15~30min, then immersed in a rotary internal spray and external shower quenching, and heated to 580℃~680℃ in a walking-beam low-temperature heating furnace, kept warm for 15~30min, and tempered; 500℃~600℃ high-temperature sizing and straightening are adopted, and the straightness is less than 0.12%L, and the out-of-roundness is less than 0.8%D;

[0028] The processing technology carries out non-destructive testing, longitudinal and transverse inspection of the inner and outer surfaces, and the flaw detection level is U2 / C; a hydrostatic pressure test is carried out, the water pressure coefficient is 0.90%, and the pressure is maintained for 10s; the inner surface is shot peened, the pipe end is processed with a groove, the pipe end is equipped with a protective ring, and the steel pipe is sprayed and painted.

[0029] In addition, the mechanical properties of the seamless pipeline are as follows: yield strength 290Mpa~395Mpa, yield strength fluctuation range ≤90MPa, tensile strength 415Mpa~535Mpa, tensile strength fluctuation range ≤110Mpa, yield strength ratio: ≤0.80, elongation ≥35%, 0℃ transverse or longitudinal full-size Charpy impact energy ≥280J, hardness: ≤180HV10, metallographic structure: duplex structure F+B back, grain size 9.0 and above, banded structure ≤2.0, the sum of four types of inclusions A, B, C, and D ≤2.

[0030] Example 2

[0031] The steel pipe material obtained by the preparation method of the present invention in this embodiment takes the production specification of 406.4×12.7 mm as an example, and the chemical composition of the prepared steel pipe is shown in Table 1:

[0032] Table 1 Statistical results of chemical composition of steel pipe wt%

[0033]

[0034] The specific preparation method is:

[0035] Steelmaking process: φ400mm cross-section tube billets are obtained through 100-ton electric furnace EAF, refining LF furnace, VD vacuum furnace, and CCM four-stream continuous casting; high-quality scrap steel, sponge iron, and molten iron are used as raw materials, with the proportion of molten iron added not less than 40%, and the screening of scrap steel is strengthened, and scrap steel with low corrosion degree such as pipe heads is used more; foam slag smelting is used in the electric furnace steelmaking process, lime is added in time, and the molten alkalinity (CaO / SiO2) is 2.5; argon is blown throughout the refining process, and secondary slag desulfurization is performed; VD treatment time is ≥18min, high vacuum time is ≥10min, and working vacuum degree is ≤0.5Torr; Ca-Si wire is fed 80m~150m before continuous casting, and molten steel is weakly stirred for ≥4min after feeding the wire; continuous casting has a stable drawing speed, the straightening temperature of the second cooling zone is ≥930℃, electromagnetic stirring is performed at the end of continuous casting, and the continuous casting billet is put into the pit for slow cooling and stacking for ≥24 hours after online cutting;

[0036] Pipe rolling process: After the tube is sawed, centering holes of φ30mm~50m are punched at both ends. The tube is heated in a ring heating furnace with a furnace temperature of 1240℃~1290℃, two-roller oblique hot piercing at 1200℃~1250℃, PQF continuous rolling unit continuous rolling temperature of 1050℃~1220℃, 12-stand three-roller sizing temperature of 830℃~910℃, cooled on a cooling bed, and sawed; the outer diameter control accuracy of the steel pipe is ±0.50%D, and the wall thickness control accuracy is ±8%t;

[0037] Heat treatment process: the steel pipe is heated to 890°C-960°C in a walking-beam high-temperature heating furnace, kept warm for 15-30 minutes, then immersed in a rotary internal spray and external shower quenching, heated to 580°C-680°C in a walking-beam low-temperature heating furnace, kept warm for 15-30 minutes, tempered, 500°C-600°C high-temperature sizing and straightening, the straightness is less than 0.12%L, and the out-of-roundness is less than 0.8%D; the mechanical properties of the line pipe of the present invention are shown in Table 2;

[0038] The test results of inclusions, structure and grain size of the steel pipe of the present invention are shown in Table 3; the test results of corrosion test of the steel pipe of the present invention are shown in Table 4;

[0039] Processing: The steel pipes are subjected to non-destructive testing, and the inner and outer surfaces are inspected longitudinally and transversely, with the flaw detection level U2 / C; each pipe is subjected to a water pressure test, and the test hydrostatic pressure is 90% of the minimum nominal yield strength, and the pressure is maintained for 10s; the inner surface is shot peened to remove sharp impurities such as scale and oxidized iron on the inner surface, and the grooves are processed, the pipe ends are equipped with protective caps, the steel pipes are sprayed with labels, and painted.

[0040] The geometric dimensions of the pipeline pipe of the present invention are:

[0041] Outer diameter range: 406.37~408.4mm(-0.5%D~+0.5%D), out-of-roundness less than 4mm(1%D)

[0042] Wall thickness range: 11.43~13.97mm(-10%t~+10%t)

[0043] Straightness: Straightness less than 0.12%*full length

[0044] Table 2 Mechanical properties of pipeline pipe

[0045]

[0046] Table 3 Test results of steel pipe inclusions, structure and grain size

[0047]

[0048] Table 4 Steel pipe HIC corrosion test results

[0049]

[0050]

[0051] Table 5 Slow strain rate tensile test in hydrogen environment

[0052]

[0053] Example 3

[0054] In this embodiment, the steel pipe material obtained by the preparation method of the present invention takes the production specification of 457×15.9 mm as an example. The chemical compositions of the two prepared steel pipes are shown in Table 6:

[0055] Table 6 Chemical composition statistics of steel pipes wt%

[0056]

[0057] The specific preparation method is:

[0058] Steelmaking process: φ400mm cross-section tube billets are obtained through 100-ton electric furnace EAF, refining LF furnace, VD vacuum furnace, and CCM four-stream continuous casting; high-quality scrap steel, sponge iron, and molten iron are used as raw materials, with the proportion of molten iron added not less than 40%, and the screening of scrap steel is strengthened, and scrap steel with low corrosion degree such as pipe heads is used more; foam slag smelting is used in the electric furnace steelmaking process, lime is added in time, and the molten alkalinity (CaO / SiO2) is 2.5; argon is blown throughout the refining process, and secondary slag desulfurization is performed; VD treatment time is ≥18min, high vacuum time is ≥10min, and working vacuum degree is ≤0.5Torr; Ca-Si wire is fed 80m~150m before continuous casting, and molten steel is weakly stirred for ≥4min after feeding the wire; continuous casting has a stable drawing speed, the straightening temperature of the second cooling zone is ≥930℃, electromagnetic stirring is performed at the end of continuous casting, and the continuous casting billet is put into the pit for slow cooling and stacking for ≥24 hours after online cutting;

[0059] Pipe rolling process: After the tube is sawed, centering holes of φ30mm~50m are punched at both ends. The tube is heated in a ring heating furnace with a furnace temperature of 1240℃~1290℃, two-roller oblique hot piercing at 1200℃~1250℃, PQF continuous rolling unit continuous rolling temperature of 1050℃~1220℃, 12-stand three-roller sizing temperature of 830℃~910℃, cooled on a cooling bed, and sawed; the outer diameter control accuracy of the steel pipe is ±0.50%D, and the wall thickness control accuracy is ±8%t;

[0060] Heat treatment process: the steel pipe is heated to 890℃~960℃ in a walking-beam high-temperature heating furnace, kept warm for 15~30min, then immersed in a rotary internal spray and external shower quenching, heated to 580℃~680℃ in a walking-beam low-temperature heating furnace, kept warm for 15~30min, tempered, 500℃~600℃ high-temperature sizing and straightening, the straightness is less than 0.12%L, and the out-of-roundness is less than 0.8%D; the mechanical properties of the line pipe of the present invention are shown in Table 7;

[0061] The test results of inclusions, structure and grain size of the steel pipe of the present invention are shown in Table 8; the corrosion test results of the steel pipe of the present invention are shown in Table 9; and the slow strain rate tensile test results in a hydrogen environment are shown in Table 10.

[0062] Processing: The steel pipes are subjected to non-destructive testing, and the inner and outer surfaces are inspected longitudinally and transversely, with the flaw detection level U2 / C; each pipe is subjected to a water pressure test, and the test hydrostatic pressure is 90% of the minimum nominal yield strength, and the pressure is maintained for 10s; the inner surface is shot peened to remove sharp impurities such as scale and oxidized iron on the inner surface, and the grooves are processed, the pipe ends are equipped with protective caps, the steel pipes are sprayed with labels, and painted.

[0063] The geometric dimensions of the pipeline pipe of the present invention are:

[0064] Outer diameter range: 456.77~459.29mm(-0.5%D~+0.5%D), out-of-roundness less than 4mm(1%D)

[0065] Wall thickness range: 14.31~17.497mm(-10%t~+10%t)

[0066] Straightness: Straightness less than 0.12%*full length

[0067] Table 7 Mechanical properties of pipeline pipe

[0068]

[0069] Table 8 Inspection results of inclusions, structure and grain size of steel pipe

[0070]

[0071] Table 9 Steel pipe HIC corrosion test results

[0072]

[0073]

[0074] Table 10 Slow strain rate tensile test in hydrogen environment

[0075]

[0076] The above embodiments describe the present invention in detail, but the contents are only preferred embodiments of the present invention and cannot be considered to limit the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the present invention.

Claims

1. A method for preparing a seamless steel pipe for submarine hydrogen transportation, characterized in that: The mass percentages of the chemical elements in the seamless steel pipe are: C: 0.08% ~ 0.14%; Si: 0.20% ~ 0.40%; Mn: 0.80% ~ 1.35%; P: ≤ 0.015%; S: ≤0.003%; Ni: ≤0.10%; Cr: 0.08%~0.20%; Mo: ≤0.10%; Cu: ≤0.15%; Nb: 0.01%~0. 04%; V: 0.01% ~ 0.04%; Ti: 0.01% ~ 0.04%; Al: 0.015% ~ 0.045%; N: 0.003% ~ 0.010%; B：≤0.0005％； H：≤0.0001％； The rest is Fe and unavoidable impurities, carbon equivalent CE IIW ≤0.34%, CEpcm≤0.22%; The method comprises the following steps: Steelmaking process: EAF electric furnace, LF refining furnace, VD vacuum furnace, CCM continuous casting to obtain tube billets; high-quality scrap steel, sponge iron, and molten iron are used as raw materials, and the proportion of molten iron added is not less than 40%; argon is blown throughout the refining process, and secondary slag desulfurization is performed; VD treatment time ≥18min, high vacuum time ≥10min, and working vacuum degree ≤0.5Torr; Feed 80m-150m of Ca-Si wire before continuous casting, and weakly stir the molten steel for ≥4min after feeding the wire; the straightening temperature of the continuous casting secondary cooling zone is ≥930℃, and electromagnetic stirring is performed at the end of continuous casting. After cutting, the continuous casting billet is put into the pit for slow cooling and pile cooling for ≥24 hours; Pipe rolling process: After the tube is sawn, centering holes of φ30mm~50m are punched at both ends. The tube is heated in a ring heating furnace with a furnace temperature of 1240℃~1290℃, two-roller oblique hot piercing at 1200℃~1250℃, PQF continuous rolling unit continuous rolling temperature of 1050℃~1220℃, 12-stand three-roller sizing temperature of 830℃~910℃, cooled on a cooling bed, and sawed; the outer diameter control accuracy of the steel pipe is ±0.50%D, and the wall thickness control accuracy is ±8%t; Heat treatment process: The steel pipe is heated to 890℃~960℃ in a walking-beam high-temperature heating furnace, kept warm for 15~30min, then immersed in a rotary internal spray and external shower quenching, and heated to 580℃~680℃ in a walking-beam low-temperature heating furnace, kept warm for 15~30min, and tempered; 500℃~600℃ high-temperature sizing and straightening are adopted, and the straightness is less than 0.12%L, and the out-of-roundness is less than 0.8%D; Processing technology: non-destructive testing, longitudinal and transverse inspection of internal and external surfaces, flaw detection level U2 / C; hydrostatic pressure test, water pressure coefficient 0.90%, pressure maintenance 10s; The inner surface is shot blasted, the pipe end is beveled, the pipe end is equipped with a protective ring, and the steel pipe is sprayed and painted.

2. The method for manufacturing a seamless steel pipe for submarine hydrogen transportation as claimed in claim 1, characterized in that: The mechanical properties of the seamless steel pipe are as follows: yield strength 290Mpa~395Mpa, yield strength fluctuation range ≤90MPa, tensile strength 415Mpa~535Mpa, tensile strength fluctuation range ≤110Mpa, yield strength ratio: ≤0.80, elongation ≥35%, 0℃ transverse full-size Charpy impact energy ≥280J, hardness: ≤180HV10, metallographic structure: duplex structure F+B back, grain size 9.0 and above, banded structure ≤2.0, and the sum of four types of inclusions A, B, C, and D ≤2.

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