Manufacturing process of hydrogen conveying bent pipe

Abstract

The invention discloses a manufacturing process of a hydrogen conveying bent pipe, and belongs to the technical field of pipeline transportation. According to the manufacturing process provided by the invention, controlled rolling treatment is firstly carried out on a bent pipe raw material to obtain a seamless steel pipe, then heating bending treatment is carried out on the seamless steel pipe, meanwhile, cooling treatment is carried out to obtain a hot-bending bent pipe, then heating treatment, quenching heat treatment and tempering heat treatment are carried out on the hot-bending bent pipe, and therefore the hydrogen conveying bent pipe is obtained. The hydrogen conveying bent pipe prepared by the process has good hydrogen environment compatibility and hydrogen induced cracking resistance, and can meet the use requirements of hydrogen conveying pipelines.

Description

Technical Field

[0001] This application relates to the field of pipeline transportation technology, and in particular to a manufacturing process for a hydrogen transport bend. Background Technology

[0002] Hydrogen energy is a clean, decarbonized new energy source with broad application prospects. It is also an ideal carrier and medium for the storage and conversion of renewable energy, and therefore has received widespread attention. With the expansion of the hydrogen energy industry, pipeline hydrogen transportation is expected to become the optimal mode of transportation for long-distance, large-scale hydrogen transport in the future.

[0003] Currently, seamless hot-bent bends, also known as hydrogen transport bends, are used to match hydrogen transport pipelines. Therefore, how to manufacture hydrogen transport bends that are compatible with hydrogen transport pipelines has become an urgent problem to be solved. Summary of the Invention

[0004] This application provides a manufacturing process for a hydrogen transport bend, which can produce a hydrogen transport bend with good hydrogen environment compatibility and resistance to hydrogen-induced cracking. The technical solution is as follows:

[0005] This application provides a manufacturing process for a hydrogen transport bend, the manufacturing process including:

[0006] Seamless steel pipes are obtained by controlling the rolling process to process the raw materials for bending pipes.

[0007] The seamless steel pipe is heated and bent using a current within a preset frequency range, and then cooled to obtain a hot-bent pipe.

[0008] The hot-bent tube is placed in a heat treatment furnace and heated until austenitized to obtain an austenitized hot-bent tube.

[0009] The austenitized hot-bent tube is subjected to quenching heat treatment to obtain a quenched heat-treated hot-bent tube.

[0010] The hot-bent pipe after quenching heat treatment is subjected to tempering heat treatment to obtain a hydrogen transport pipe.

[0011] In one possible implementation, the step of subjecting the austenitized hot-bent tube to quenching heat treatment to obtain the quenched heat-treated hot-bent tube includes:

[0012] The austenitized hot-bent tube is placed in a brine solution with a concentration of 6% to 8% and a temperature not exceeding 35°C for quenching heat treatment to obtain the quenched hot-bent tube.

[0013] In another possible implementation, the step of tempering the hot-bent pipe after quenching heat treatment to obtain the hydrogen transport pipe includes:

[0014] The heat preservation time of the seamless steel pipe is determined based on its wall thickness.

[0015] The hot-bent pipe after quenching heat treatment is placed in the heat treatment furnace for tempering heat treatment. The tempering temperature is 520-650℃, and the holding time is greater than or equal to the holding time of the steel pipe, to obtain the hydrogen transport pipe.

[0016] In another possible implementation, the step of placing the hot-bent tube in a heat treatment furnace and heating it until austenitized to obtain an austenitized hot-bent tube includes:

[0017] The hot-bent tube is placed in a heat treatment furnace and heated to a temperature of 880-1000°C until it becomes austenitic, thus obtaining the austenitic hot-bent tube.

[0018] In another possible implementation, the process of heating and bending the seamless steel pipe using a current within a preset frequency range, while simultaneously cooling it to obtain a hot-bent pipe, includes:

[0019] The seamless steel pipe is heated and bent on a pipe bending machine using a current of 700-1500Hz. The heating temperature is 880-1000℃, the bending speed is 20-100mm / min, and the pipe is cooled at the same time to obtain a hot-bent pipe with a curvature radius of 2-10m.

[0020] In another possible implementation, cooling is achieved by spraying water at a rate of not less than 15°C / s.

[0021] In another possible implementation, the seamless steel pipe has a diameter of 219–813 mm and a wall thickness of 10–40 mm.

[0022] In another possible implementation, the pipe bending material comprises the following components by weight percentage:

[0023] 0.05%–0.12% carbon, 0.10%–0.30% silicon, 0.8%–1.4% manganese, not more than 0.020% phosphorus, not more than 0.010% sulfur, not more than 0.03% aluminum, 0.15%–0.35% nickel, not more than 0.03% chromium, not more than 0.05% copper, not more than 0.03% vanadium, not more than 0.05% niobium, not more than 0.15% molybdenum, not more than 0.04% titanium, not more than 0.0003% boron, with the balance being iron.

[0024] In another possible implementation, the carbon equivalent of the raw material for the bent pipe is 0.29% to 0.38%.

[0025] In another possible implementation, the cold cracking sensitivity coefficient of the raw material for the bent pipe is no greater than 0.21%.

[0026] This application provides a manufacturing process for a hydrogen transport bend. The process first involves controlled rolling of the raw material to obtain a seamless steel pipe. Then, the seamless steel pipe is heated and bent while simultaneously cooling to obtain a hot-bent pipe. Finally, the hot-bent pipe undergoes heating, quenching, and tempering heat treatments to obtain the hydrogen transport bend. The hydrogen transport bend produced by this process exhibits good hydrogen environment compatibility and resistance to hydrogen-induced cracking, meeting the requirements for hydrogen transport pipelines.

[0027] It should be understood that the above general description and the following detailed description are merely exemplary and do not limit this disclosure. Attached Figure Description

[0028] Figure 1 This is a flowchart of a manufacturing process for a hydrogen transport bend provided in an embodiment of this application. Detailed Implementation

[0029] To make the technical solution and advantages of this application clearer, the embodiments of this application will be described in further detail below.

[0030] The terms "first," "second," "third," and "fourth," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or apparatuses.

[0031] This application provides a manufacturing process for a hydrogen transport bend, see [link to relevant documentation]. Figure 1 The manufacturing process includes the following steps:

[0032] Step 101: The raw material for bending is subjected to controlled rolling process to obtain seamless steel pipe.

[0033] In this embodiment of the application, the raw material for bending pipes comprises the following components by weight percentage:

[0034] 0.05%–0.12% carbon (C), 0.10%–0.30% silicon (Si), 0.8%–1.4% manganese (Mn), not more than 0.020% phosphorus (P), not more than 0.010% sulfur (S), not more than 0.03% aluminum (Al), 0.15%–0.35% nickel (Ni), not more than 0.03% chromium (Cr), not more than 0.05% copper (Cu), not more than 0.03% vanadium (V), not more than 0.05% niobium (Nb), not more than 0.15% molybdenum (Mo), not more than 0.04% titanium (Ti), not more than 0.0003% boron (B), with the balance being iron (Fe).

[0035] In one possible implementation, the weight percentage of C is 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.10%, 0.11%, or 0.12%; the weight percentage of Si is 0.10%, 0.15%, 0.20%, 0.24%, 0.25%, or 0.30%; the weight percentage of Mn is 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, or 1.4%; and the weight percentage of P is 0.001%, 0.002%, 0.005%, 0.01%, or 0.0%. The weight percentages of S, Al, Ni, and Cr are 15%, 0.020%, 0.001%, 0.002%, 0.005%, 0.007%, 0.008%, 0.009%, or 0.010%, 0.01%, 0.015%, 0.02%, 0.025%, or 0.03%, 0.15%, 0.018%, 0.20%, 0.25%, 0.28%, 0.30%, or 0.35%, respectively. The weight percentages of Cu are 0.01%, 0.012%, 0.015%, 0.02%, 0.025%, 0.03%, 0.035%, 0.04%, 0.045%, or 0.05%; the weight percentages of V are 0.01%, 0.015%, 0.02%, 0.025%, 0.027%, or 0.03%; and the weight percentages of Nb are 0.01%, 0.015%, 0.02%, 0.025%, 0.03%, 0.035%, 0.04%, 0.045%, or 0.05%. The weight percentages of Mo are 0.01%, 0.02%, 0.03%, 0.05%, 0.07%, 0.08%, 0.09%, 0.10%, 0.12%, or 0.15%; the weight percentages of Ti are 0.001%, 0.002%, 0.008%, 0.01%, 0.015%, 0.02%, 0.025%, 0.03%, 0.035%, or 0.04%; and the weight percentages of B are 0.0001%, 0.00015%, 0.0002%, 0.00025%, or 0.0003%.

[0036] Furthermore, the carbon equivalent (Ceq) of the raw material for the bent pipe is 0.29% to 0.38%, and the cold cracking sensitivity coefficient (Pcm) is no greater than 0.21%.

[0037] In this embodiment of the application, the carbon equivalent (Ceq) can be obtained by the following formula:

[0038]

[0039] The cold cracking sensitivity coefficient (Pcm) can be obtained by the following formula:

[0040]

[0041] Wherein, C, Si, Mn, Cr, Mo, V, Ni, Cu and B represent the weight percentage of each element in the raw material for bending pipes.

[0042] In this step, the heating temperature, rolling temperature, and deformation temperature of the raw material for bending are controlled by a controlled rolling process to achieve controlled rolling treatment of the raw material, thereby obtaining seamless steel pipes with a diameter of 219–813 mm and a wall thickness of 10–40 mm. The raw material for bending can be L245–L415 grade steel pipe.

[0043] In the embodiments of this application, the total alloy content of C and alloying elements such as Mn, Mo, Cr, Ni, Cu, Nb, V, and Ti, calculated according to Ceq, must be greater than 0.29%, of which the C content must be greater than 0.05%, to ensure high hardenability of the material and to ensure that the bent pipe obtains a sorbitic structure after heating, bending, quenching, cooling, and tempering, thereby achieving good hydrogen environment compatibility and resistance to hydrogen-induced cracking. To ensure high impact performance of the bent pipe body, the Ni content can be appropriately increased to lower the low-temperature embrittlement transition temperature of the steel; therefore, the Ni content is ≥0.15%. To ensure low hardness of the bent pipe body, the Cr content is strictly controlled to ≤0.03%. To reduce the formation of hydrogen-sensitive structures such as segregation, impurities, and hard phases while considering the weldability of the material, the C, Mn, and Ceq elements are strictly controlled, with 0.05% ≤ C ≤ 0.12%, 0.8% ≤ Mn ≤ 1.4%, and 0.29% ≤ Ceq ≤ 0.38%. In addition, the production process employs ladle refining and homogenization technologies, strictly controls the grades of non-metallic inclusions (A, B, C, and D), reduces banded structures and segregation, and improves the grain size of the microstructure.

[0044] Among them, the A, B, C and D classifications of non-metallic inclusions refer to: A is sulfide, B is oxide, C is silicate, and D is spherical oxide.

[0045] It is precisely because of the design of the raw material composition of the bend tube, or in other words, the raw material of the bend tube has the above-mentioned composition, and in addition to the manufacturing process disclosed in this application, that a hydrogen transport bend tube that meets the requirements can be manufactured.

[0046] Step 102: The seamless steel pipe is heated and bent using a current within a preset frequency range, and then cooled to obtain a hot-bent pipe.

[0047] In this step, a medium-frequency current of 700-1500Hz can be used on a pipe bending machine to heat and bend the seamless steel pipe. The heating temperature is 880-1000℃, the bending speed is 20-100mm / min, and cooling is performed at the same time to obtain a hot-bent pipe with a curvature radius of 2-10m.

[0048] In this process, after the seamless steel pipe is bent, it is quickly cooled by spraying water at a rate of not less than 15℃ / s to obtain a hot-bent pipe.

[0049] In one possible implementation, the heating temperature is 880℃, 900℃, 920℃, 940℃, 960℃, 980℃ or 1000℃, the bending speed is 20mm / min, 30mm / min, 40mm / min, 50mm / min, 60mm / min, 70mm / min, 80mm / min, 90mm / min or 100mm / min, and the cooling rate is 20℃ / s, 22℃ / s, 25℃ / s or 30℃ / s.

[0050] Step 103: Place the hot-bent tube in a heat treatment furnace and heat it until it becomes austenitic to obtain an austenitic hot-bent tube.

[0051] The hot-bent tube is placed in a heat treatment furnace and heated to a temperature of 880–1000°C until it becomes austenitic, thus obtaining an austenitic hot-bent tube.

[0052] The heat treatment furnace can be a natural gas heat treatment furnace, an electric heat treatment furnace, or other types of heat treatment furnaces; no specific limitation is made. Furthermore, the heating temperature can be 880℃, 900℃, 920℃, 940℃, 960℃, 980℃, or 1000℃.

[0053] Step 104: Perform quenching heat treatment on the austenitized hot bent pipe to obtain the quenched hot bent pipe.

[0054] After obtaining the austenitized hot-bent tube, the austenitized hot-bent tube is placed in a brine solution with a concentration of 6% to 8% and a temperature not exceeding 35°C for quenching heat treatment within a preset time to obtain the quenched hot-bent tube.

[0055] The preset time should not exceed 120 seconds; for example, the preset time can be 30 seconds, 40 seconds, 50 seconds, 60 seconds, 70 seconds, 80 seconds, 100 seconds, 110 seconds, or 120 seconds. The concentration of the saline solution can be 6%, 6.5%, 7%, 7.5%, or 8%, and the temperature of the saline solution can be 20℃, 25℃, 30℃, or 35℃.

[0056] Step 105: Perform tempering heat treatment on the hot-bent pipe after quenching heat treatment to obtain the hydrogen transport bend.

[0057] Before performing tempering heat treatment on the hot bent pipe after quenching heat treatment, the holding time of the steel pipe can be determined according to the wall thickness of the seamless steel pipe. Then, the hot bent pipe after quenching heat treatment is placed in a heat treatment furnace for tempering heat treatment. The tempering temperature is 520-650℃, and the holding time is greater than or equal to the holding time of the steel pipe, thus obtaining the hydrogen transport bend.

[0058] In this embodiment, the heat preservation time for each 10mm thick steel pipe is not less than 30 minutes. Therefore, when determining the heat preservation time of the steel pipe, the quotient of the seamless steel pipe wall thickness and 10 can be determined first, and then the product of the quotient and 30 can be calculated to obtain the heat preservation time. For example, if the wall thickness of the seamless steel pipe is 12mm, then the heat preservation time is (12 / 10)*30 = 36, meaning the heat preservation time is greater than or equal to 36 minutes.

[0059] In addition, the tempering temperature can be 520℃, 540℃, 560℃, 580℃, 600℃, 620℃ or 650℃.

[0060] This application provides a manufacturing process for a hydrogen transport bend. The process first involves controlled rolling of the raw material to obtain a seamless steel pipe. Then, the seamless steel pipe is heated and bent while simultaneously cooling to obtain a hot-bent pipe. Finally, the hot-bent pipe undergoes heating, quenching, and tempering heat treatments to obtain the hydrogen transport bend. The hydrogen transport bend produced by this process exhibits good hydrogen environment compatibility and resistance to hydrogen-induced cracking, meeting the requirements for hydrogen transport pipelines.

[0061] The technical solution of this application will be described in detail below through specific embodiments.

[0062] Example 1

[0063] Step 1: The raw material for bending pipe is subjected to controlled rolling process to obtain seamless steel pipe with L245 steel grade, diameter of 406.4mm and wall thickness of 12mm.

[0064] The composition of the raw materials for the bent pipe can be found in Table 1, with the balance being Fe.

[0065] Table 1

[0066] Components C Si Mn P S Al Ni content 0.09％ 0.24％ 1.0％ 0.001％ 0.007％ 0.03％ 0.15％ Components Cr Cu V Nb Mo Ti B content 0.01％ 0.012％ 0.03％ 0.025％ 0.1％ 0.001％ 0.0003％

[0067] Based on the content of the above components, the carbon equivalent (Ceq) of the pipe bending raw material can be calculated to be 0.295%, and the cold crack sensitivity coefficient (Pcm) is 0.161%.

[0068] Step 2: The seamless steel pipe is heated and bent on a pipe bending machine using a current of 700-1500Hz. The heating temperature is 900±20℃ and the bending speed is 80±2mm / min. At the same time, it is cooled by water spraying at a cooling rate of 20℃ / s, resulting in a hot-bent pipe with a curvature radius of R=6D (R=2438.4mm).

[0069] Step 3: Place the hot-bent pipe in a natural gas heat treatment furnace and heat it at a temperature of 910±20℃ for 8 minutes to obtain an austenitized hot-bent pipe.

[0070] Step 4: Immerse the austenitized hot-bent tube in a brine solution with a concentration of 6% to 8% and a temperature not exceeding 35°C for quenching heat treatment to obtain the quenched hot-bent tube.

[0071] Step 5: Place the hot-bent pipe after quenching heat treatment in a natural gas heat treatment furnace for tempering heat treatment. The tempering temperature is 520℃ and the holding time is 40min to obtain the hydrogen transport pipe.

[0072] After obtaining the hydrogen transport bend, mechanical properties, hydrogen environment compatibility, and resistance to hydrogen-induced cracking were tested on the hydrogen transport bend. The test results are shown in Tables 2 and 3, respectively.

[0073] Table 2

[0074]

[0075] Table 3

[0076]

[0077] Example 2

[0078] Step 1: The raw material for bending is subjected to controlled rolling process to obtain a seamless steel pipe with L290 steel grade, a diameter of 508mm and a wall thickness of 17.5mm.

[0079] The composition of the raw materials for the bent pipe can be found in Table 4, with the balance being Fe.

[0080] Table 4

[0081] Components C Si Mn P S Al Ni content 0.11％ 0.225％ 1.15％ 0.001％ 0.007％ 0.03％ 0.17％ Components Cr Cu V Nb Mo Ti B content 0.01％ 0.012％ 0.027％ 0.02％ 0.01％ 0.001％ 0.0003％

[0082] Based on the content of the above components, the carbon equivalent (Ceq) of the pipe bending raw material can be calculated to be 0.323%, and the cold crack sensitivity coefficient (Pcm) is 0.182%.

[0083] Step 2: The seamless steel pipe is heated and bent on a pipe bending machine using a current of 700-1500Hz. The heating temperature is 920±20℃ and the bending speed is 60±2mm / min. At the same time, it is cooled by water spraying at a cooling rate of 22℃ / s, resulting in a hot-bent pipe with a curvature radius of R=8D (R=4064mm).

[0084] Step 3: Place the hot-bent pipe in a natural gas heat treatment furnace and heat it at a temperature of 940±20℃ for 10 minutes to obtain an austenitized hot-bent pipe.

[0085] Step 4: Immerse the austenitized hot-bent tube in a brine solution with a concentration of 6% to 8% and a temperature not exceeding 35°C for quenching heat treatment to obtain the quenched hot-bent tube.

[0086] Step 5: Place the hot-bent pipe after quenching heat treatment in a natural gas heat treatment furnace for tempering heat treatment. The tempering temperature is 520℃ and the holding time is 55min to obtain the hydrogen transport pipe.

[0087] After obtaining the hydrogen transport bend, mechanical properties, hydrogen environment compatibility, and resistance to hydrogen-induced cracking were tested on the hydrogen transport bend. The test results are shown in Tables 5 and 6, respectively.

[0088] Table 5

[0089]

[0090] Table 6

[0091]

[0092] Example 3

[0093] Step 1: The raw material for bending pipe is subjected to controlled rolling process to obtain seamless steel pipe with L360 steel grade, diameter of 610mm and wall thickness of 24mm.

[0094] The composition of the raw materials for the bent pipe can be found in Table 7, with the balance being Fe.

[0095] Table 7

[0096] Components C Si Mn P S Al Ni content 0.11％ 0.25％ 1.3％ 0.001％ 0.007％ 0.03％ 0.25％ Components Cr Cu V Nb Mo Ti B content 0.01％ 0.012％ 0.03％ 0.025％ 0.01％ 0.001％ 0.0003％

[0097] Based on the content of the above components, the carbon equivalent (Ceq) of the pipe bending raw material can be calculated to be 0.354%, and the cold cracking sensitivity coefficient (Pcm) is 0.192%.

[0098] Step 2: The seamless steel pipe is heated and bent on a pipe bending machine using a current of 700-1500Hz. The heating temperature is 945±20℃ and the bending speed is 40±2mm / min. At the same time, it is cooled by water spraying at a cooling rate of 25℃ / s, resulting in a hot-bent pipe with a curvature radius of R=5D (R=3050mm).

[0099] Step 3: Place the hot-bent pipe in a natural gas heat treatment furnace and heat it at a temperature of 960±20℃ for 13 minutes to obtain an austenitized hot-bent pipe.

[0100] Step 4: Immerse the austenitized hot-bent tube in a brine solution with a concentration of 6% to 8% and a temperature not exceeding 35°C for quenching heat treatment to obtain the quenched hot-bent tube.

[0101] Step 5: Place the hot-bent pipe after quenching heat treatment in a natural gas heat treatment furnace for tempering heat treatment. The tempering temperature is 550℃ and the holding time is 80min to obtain the hydrogen transport pipe.

[0102] After obtaining the hydrogen transport bend, mechanical properties, hydrogen environment compatibility, and resistance to hydrogen-induced cracking were tested on the hydrogen transport bend. The test results are shown in Tables 8 and 9, respectively.

[0103] Table 8

[0104]

[0105]

[0106] Table 9

[0107]

[0108] Example 4

[0109] Step 1: The raw material for bending is subjected to controlled rolling process to obtain a seamless steel pipe with L360 steel grade, a diameter of 711mm and a wall thickness of 38mm.

[0110] The composition of the raw materials for the bent pipe can be found in Table 10, with the balance being Fe.

[0111] Table 10

[0112] Components C Si Mn P S Al Ni content 0.11％ 0.25％ 1.3％ 0.001％ 0.007％ 0.03％ 0.3％ Components Cr Cu V Nb Mo Ti B content 0.01％ 0.012％ 0.03％ 0.025％ 0.1％ 0.001％ 0.0003％

[0113] Based on the content of the above components, the carbon equivalent (Ceq) of the pipe bending raw material can be calculated to be 0.375%, and the cold cracking sensitivity coefficient (Pcm) is 0.20%.

[0114] Step 2: The seamless steel pipe is heated and bent on a pipe bending machine using a current of 700-1500Hz. The heating temperature is 965±20℃ and the bending speed is 25±2mm / min. At the same time, it is cooled by water spraying at a cooling rate of 22℃ / s, resulting in a hot-bent pipe with a curvature radius of R=12D (R=8532mm).

[0115] Step 3: Place the hot-bent pipe in a natural gas heat treatment furnace and heat it at a temperature of 980±20℃ for 20 minutes to obtain an austenitized hot-bent pipe.

[0116] Step 4: Immerse the austenitized hot-bent tube in a brine solution with a concentration of 6% to 8% and a temperature not exceeding 35°C for quenching heat treatment to obtain the quenched hot-bent tube.

[0117] Step 5: Place the hot-bent pipe after quenching heat treatment in a natural gas heat treatment furnace for tempering heat treatment. The tempering temperature is 620℃ and the holding time is 120min to obtain the hydrogen transport pipe.

[0118] After obtaining the hydrogen transport bend, mechanical properties, hydrogen environment compatibility, and resistance to hydrogen-induced cracking were tested on the hydrogen transport bend. The test results are shown in Tables 11 and 12, respectively.

[0119] Table 11

[0120]

[0121] Table 12

[0122]

[0123]

[0124] The test results from Examples 1-4 show that the hydrogen transport bend prepared in this application improves the resistance of the bend's metal body to hydrogen damage under high-pressure hydrogen conditions, giving the bend good hydrogen environment compatibility. Specifically, the slow strain rate tensile (SSRT) test showed that the reduction of area in the hydrogen environment / reduction of area in the air or nitrogen environment was ≥0.7; the fracture toughness test in a pure hydrogen environment showed that the fracture toughness K... ic ≥80MPa·m 1 / 2 The material exhibits excellent fatigue life under the highest stress, stress amplitude, and fluctuation frequency set for pressure pipelines, meeting the requirements for use in high-pressure hydrogen transmission pipelines.

[0125] Furthermore, the yield strength and tensile strength of the bend pipe body are not less than the strength requirements of the corresponding steel grade pipe in ISO 3183 or GB / T 9711, and the average low-temperature impact toughness of the bend pipe body at -45℃ is greater than 90J, which fully meets the mechanical performance requirements of L245-L415 steel grade bend pipes and can be used for hot-bent bend pipes for hydrogen transmission pipelines in cold regions.

[0126] Furthermore, the bends prepared according to the embodiments of this application exhibit excellent resistance to hydrogen-induced cracking. The pipe body metal was subjected to a hydrogen-induced cracking test according to GB / T8650 and using solution B, and the results met the following acceptance limits:

[0127] (a) Crack sensitivity rate (CSR) is not greater than 0.5%;

[0128] (b) Crack length ratio (CLR) not greater than 5%;

[0129] (c) Crack thickness ratio (CTR) is not greater than 1.5%.

[0130] Solution B is artificial seawater containing saturated H2S at room temperature and pressure.

[0131] Therefore, the manufacturing process provided in this application can produce hydrogen transport bends with good hydrogen environment compatibility and resistance to hydrogen-induced cracking, thereby meeting the requirements for use in hydrogen transport pipelines.

[0132] The above description is only for the purpose of enabling those skilled in the art to understand the technical solution of this application, and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A process for manufacturing a hydrogen feed tube, characterized by, The manufacturing process comprises: controlling and rolling the bending pipe raw material through a controlled rolling process to obtain a seamless steel pipe; heating and bending the seamless steel pipe by using a current with a preset frequency range, and simultaneously performing cooling treatment to obtain a hot bending pipe; placing the hot bending pipe in a heat treatment furnace to heat to austenitization to obtain an austenitized hot bending pipe; quenching the austenitized hot bending pipe to obtain a quenched hot bending pipe; tempering the quenched hot bending pipe to obtain a hydrogen conveying bending pipe.

2. The manufacturing process of claim 1, wherein, The quenching of the austenitized hot bending pipe to obtain a quenched hot bending pipe comprises: placing the austenitized hot bending pipe in brine with a concentration of 6-8% and a temperature not higher than 35 ℃ to perform quenching heat treatment to obtain a quenched hot bending pipe.

3. The manufacturing process of claim 1, wherein, The tempering of the quenched hot bending pipe to obtain a hydrogen conveying bending pipe comprises: determining a pipe holding time according to the wall thickness of the seamless steel pipe; placing the quenched hot bending pipe in the heat treatment furnace to perform tempering heat treatment, the tempering temperature being 520-650 ℃, and the holding time being greater than or equal to the pipe holding time to obtain the hydrogen conveying bending pipe.

4. The manufacturing process of claim 1, wherein, The placing of the hot bending pipe in a heat treatment furnace to heat to austenitization to obtain an austenitized hot bending pipe comprises: placing the hot bending pipe in a heat treatment furnace to heat, the heating temperature being 880-1000 ℃, and the austenitization of the hot bending pipe being waited for to obtain the austenitized hot bending pipe.

5. The manufacturing process of claim 1, wherein, The heating and bending of the seamless steel pipe by using a current with a preset frequency range, and simultaneously performing cooling treatment to obtain a hot bending pipe comprises: heating and bending the seamless steel pipe on a bending machine by using a current with a frequency of 700-1500 Hz, the heating temperature being 880-1000 ℃, the bending speed being 20-100 mm / min, and simultaneously performing cooling treatment to obtain a hot bending pipe with a curvature radius of 2-10 m.

6. The manufacturing process of claim 5, wherein, The cooling treatment is performed by means of water spraying, and the cooling speed is not less than 15 ℃ / s.

7. The manufacturing process of claim 1, wherein, The seamless steel pipe has a pipe diameter of 219-813 mm and a wall thickness of 10-40 mm.

8. The manufacturing process of claim 1, wherein, The bending pipe raw material comprises the following components by weight percentage: 0.05-0.12% of carbon, 0.10-0.30% of silicon, 0.8-1.4% of manganese, not more than 0.020% of phosphorus, not more than 0.010% of sulfur, not more than 0.03% of aluminum, 0.15-0.35% of nickel, not more than 0.03% of chromium, not more than 0.05% of copper, not more than 0.03% of vanadium, not more than 0.05% of niobium, not more than 0.15% of molybdenum, not more than 0.04% of titanium, not more than 0.0003% of boron, and the balance being iron.

9. The manufacturing process of claim 8, wherein, The carbon equivalent of the bending pipe raw material is 0.29-0.38%.

10. The manufacturing process of claim 9, wherein, The cold cracking sensitivity coefficient of the bending pipe raw material is not more than 0.21%.

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