A hydrogen transport pipeline steel and a method for manufacturing the same

Abstract

The application relates to the technical field of steel production, in particular to a hydrogen transmission pipeline steel and a preparation method thereof. The method comprises the following steps: rough rolling of a steel billet to obtain an intermediate billet; wherein the rough rolling comprises a longitudinal rolling stage, and the process parameters of each pass of the longitudinal rolling are controlled; finish rolling of the intermediate billet, and the reduction of the finish rolling is controlled to obtain a hot-rolled plate; pre-straightening of the hot-rolled plate, and the process parameters of the pre-straightening are controlled, and then cooling; hot straightening of the hot-rolled plate after cooling, and the reduction of the hot straightening is controlled to obtain the hydrogen transmission pipeline steel. The application solves the technical problem that the comprehensive performance of the existing hydrogen transmission pipeline steel is difficult to meet the user demand.

Description

Technical Field

[0001] This application relates to the field of steel preparation technology, and in particular to a steel for hydrogen pipelines and a method for preparing the same. Background Technology

[0002] Peak carbon emissions and carbon neutrality are important commitments my country has made to the world, and hydrogen energy will play a crucial role in achieving these goals. In recent years, my country's hydrogen energy industry has seen rapid growth, with the government actively supporting its development. Hydrogen energy industry plans, project layouts, and support policies have been successively introduced, technological innovations are emerging, and infrastructure construction is underway. The hydrogen energy industry is now on a fast track of development. This rapid development has created a demand for large-scale, long-distance, and low-cost hydrogen transportation. Compared to high-pressure gaseous and cryogenic liquid transportation, pipelines offer advantages in both efficiency and cost, and are suitable for long-distance, high-volume transportation, possessing unparalleled advantages and promising application prospects. Therefore, as the hydrogen energy industry expands, pipeline transportation will inevitably become the optimal mode of transport for long-distance, large-scale hydrogen transportation in the future.

[0003] Currently, because pipeline materials are used in high-pressure, high-purity hydrogen environments for extended periods, they are highly susceptible to problems such as ductility and plasticity loss, and hydrogen-induced fracture. Summary of the Invention

[0004] This application provides a steel for hydrogen pipelines and a method for preparing the same, in order to solve the technical problem that the overall performance of existing steels for hydrogen pipelines is difficult to meet user needs.

[0005] In a first aspect, this application provides a method for preparing steel for hydrogen pipelines, the method comprising:

[0006] The steel billet is rough rolled to obtain an intermediate billet; wherein the rough rolling includes a longitudinal rolling stage, and the process parameters of each pass of the longitudinal rolling are controlled.

[0007] The intermediate billet is precision rolled, and the reduction amount of the precision rolling is controlled to obtain a hot-rolled plate;

[0008] The hot-rolled plate is pre-straightened, and the process parameters for pre-straightening are controlled, followed by cooling.

[0009] The cooled hot-rolled plate is hot-straightened, and the reduction amount of the hot straightening is controlled to obtain steel for hydrogen pipelines.

[0010] Optionally, the process parameters for each pass of the longitudinal rolling process include:

[0011] Water-based rolling mode, rolling temperature of the last three passes of longitudinal rolling, and single reduction rate of the last three passes of longitudinal rolling.

[0012] Optionally, the water usage mode is as follows: high-pressure descaling water is sprayed in each rolling pass of the longitudinal rolling process to cool the surface of the steel billet.

[0013] Optionally, the rolling temperature of the last three longitudinal rolling passes is 960–980°C.

[0014] Optionally, the single reduction rate of the last three passes of the longitudinal rolling is 25% to 35%.

[0015] Optionally, the reduction amount of the finishing mill includes: the reduction amount of the last two passes of the finishing mill is 1.0 to 1.5 mm.

[0016] Optionally, the pre-straightening process parameters include: pre-straightening inlet depressurization, pre-straightening outlet depressurization, and pre-straightening bite speed.

[0017] Optionally, the pre-straightening inlet depressurization is 2.5–3.0 mm, the pre-straightening outlet depressurization is 0.6–0.8 mm, and the pre-straightening bite speed is 0.7–1.0 m / s.

[0018] Optionally, the reduction amount in the thermal straightening includes: setting the inlet reduction amount and the outlet reduction amount of the straightening roller, respectively; wherein,

[0019] The inlet reduction of the first 7 straightening rollers is 3-4 mm, and the outlet reduction of the first 7 straightening rollers is 0.4-0.8 mm.

[0020] The inlet pressure of the last four straightening rollers is 1.0 to 1.5 mm, and the outlet pressure of the last four straightening rollers is 0 to 0.2 mm.

[0021] Secondly, this application provides a steel for hydrogen pipelines, which is prepared by the method described in any embodiment of the first aspect.

[0022] The technical solutions provided in this application have the following advantages compared with the prior art:

[0023] The method for preparing hydrogen pipeline steel provided in this application controls the process parameters during the roughing and longitudinal rolling stages. The purpose of this control is to allow rolling deformation to penetrate from the surface of the billet to the core, effectively flattening and refining the austenite grains. Controlling the reduction during finishing rolling and pre-straightening the hot-rolled plate aims to ensure a flat plate shape before water cooling and improve the uniformity of water cooling. Controlling the reduction during hot straightening effectively ensures the plate shape. This method significantly improves the overall performance of hydrogen pipeline steel products, ensuring the safety and reliability of hydrogen pipelines during service. Attached Figure Description

[0024] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0025] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a schematic flowchart illustrating a method for preparing steel for hydrogen pipelines, provided in an embodiment of this application. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0028] Various embodiments of this application may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of this application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the referred range.

[0029] In this application, unless otherwise stated, directional terms such as "upper" and "lower" specifically refer to the drawing directions in the accompanying drawings. Furthermore, in the description of this application, terms such as "comprising" and "including" mean "including but not limited to." In this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. In this document, "and / or" describes the relationship between related objects, indicating that three relationships can exist; for example, A and / or B can represent: A alone, A and B simultaneously, or B alone. A and B can be singular or plural. In this document, "at least one" means one or more, and "more than one" means two or more. "At least one," "at least one of the following," or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, "at least one of a, b, or c" or "at least one of a, b, and c" can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be a single or multiple.

[0030] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0031] Firstly, this application provides a method for preparing steel for hydrogen pipelines; please refer to [link to relevant documentation]. Figure 1 The method includes:

[0032] Because pipeline materials operate under high-pressure, high-purity hydrogen environments for extended periods, they are highly susceptible to ductility and plasticity loss, hydrogen-induced fracture, and other problems. Users have imposed stringent technical requirements on the low-temperature crack arrest toughness and performance consistency of pipeline materials, demanding that the strength difference between plates be ≤40 MPa, the thickness and section hardness difference be ≤20 HV10, the -20℃ drop weight DWTT shear area be ≥96%, and the plate shape unevenness be ≤6 mm / m. Therefore, during the hot-rolling production of steel for hydrogen pipelines, reasonable process methods should be designed to improve the performance indicators, performance consistency, and plate shape dimensions of the steel plates, thereby ensuring the safe operation of hydrogen pipelines.

[0033] S1. Rough rolling of steel billet to obtain intermediate billet; wherein, the rough rolling includes a longitudinal rolling stage, and the process parameters of each pass of the longitudinal rolling are controlled;

[0034] In some embodiments, the process parameters for each pass of the longitudinal rolling include:

[0035] Water-based rolling mode, rolling temperature of the last three passes of longitudinal rolling, and single reduction rate of the last three passes of longitudinal rolling.

[0036] In some embodiments, the water usage pattern is as follows: high-pressure descaling water is sprayed during each rolling pass of the longitudinal rolling process to cool the surface of the billet.

[0037] In this embodiment, high-pressure descaling water is sprayed in each pass of the roughing and longitudinal rolling stage of the billet to rapidly cool the surface of the billet. The surface temperature drops by 40-55°C instantly, achieving a low surface temperature and a high center temperature (i.e., cold outside and hot inside) to achieve the effect of surface hardening and high-penetration deformation.

[0038] In some embodiments, the rolling temperature of the last three longitudinal rolling passes is 960–980°C.

[0039] In some embodiments, the single reduction rate of the last three passes of the longitudinal rolling is 25-35%.

[0040] Controlling the rolling temperature of the last three passes in longitudinal rolling to 960–980℃, with a single-pass reduction rate of 25–35%, has the following positive effects: it provides excellent prerequisites for the final steel plate product to obtain a refined and uniform grain structure, thereby improving the strength and low-temperature toughness of the steel plate. If the rolling temperature is too high, it will weaken the austenite grain refinement effect to some extent, directly affecting the degree of grain refinement of the phase transformation structure of the rolled steel plate; if the rolling temperature is too low, it may lead to an excessively large peak torque of the mill, causing the mill to automatically split the passes, making it difficult to control the single-pass reduction rate at 25–35%. Specifically, the rolling temperature of the last three passes in longitudinal rolling can be 960℃, 970℃, 980℃, etc. If the single-pass reduction rate is too high, due to the limited capacity of the mill, it will pose a certain risk to the mill equipment to some extent; if the single-pass reduction rate is too low, it will affect the penetration effect of rolling deformation into the core of the billet to some extent, making it impossible to achieve the refinement of the austenite structure in the core of the billet. Specifically, the single reduction rate in the three passes of the rolling mill can be 25%, 30%, 35%, etc.

[0041] S2. The intermediate billet is precision rolled, and the reduction amount of the precision rolling is controlled to obtain a hot-rolled plate;

[0042] In some embodiments, the reduction in the finishing mill includes a reduction of 1.0 to 1.5 mm in the last two passes of the finishing mill.

[0043] The positive effect of controlling the reduction in the last two passes of finishing rolling to 1.0–1.5 mm is to improve the flatness of the finished sheet. If the reduction in the last two passes of finishing rolling is too high, the rolling temperature is low and the finishing speed is high, which can easily lead to uneven thickness distribution of the steel sheet, i.e., the thickness difference within the same plate will exceed the standard. If the reduction in the last two passes of finishing rolling is too low, the amount of plastic deformation of the material is too small, which makes it difficult to improve the flatness of the output sheet to a certain extent. Specifically, the reduction in the last two passes of finishing rolling can be 1.0 mm, 1.3 mm, 1.5 mm, etc.

[0044] S3. The hot-rolled plate is pre-straightened, and the process parameters of the pre-straightening are controlled, followed by cooling.

[0045] In some embodiments, the pre-straightening process parameters include: pre-straightening inlet depressurization, pre-straightening outlet depressurization, and pre-straightening bite speed.

[0046] In some embodiments, the pre-straightening inlet depressurization is 2.5–3.0 mm, the pre-straightening outlet depressurization is 0.6–0.8 mm, and the pre-straightening bite speed is 0.7–1.0 m / s.

[0047] The positive effects of controlling the above-mentioned pre-straightening process parameters are: ensuring the flatness of the plate shape before water cooling, laying a good foundation for the uniformity of water cooling of the steel plate, thereby effectively improving the consistency of the overall plate strength, toughness, and hardness. Setting the above process parameters too high will, to some extent, reduce the pre-straightening speed of the steel plate, directly affecting the water cooling temperature of the steel plate, resulting in a lower temperature. Setting the above process parameters too low will not meet the requirement that plastic deformation occurs in 50% of the steel plate's thickness direction, making it impossible to eliminate the problem of poor rolled plate shape. Specifically, the pre-straightening inlet reduction can be 2.5mm, 2.8mm, or 3.0mm, the pre-straightening outlet reduction can be 0.6mm, 0.7mm, or 0.8mm, etc., and the pre-straightening bite speed can be 0.7m / s, 0.9m / s, or 1.0m / s, etc.

[0048] S4. The cooled hot-rolled plate is hot-straightened, and the reduction amount of the hot straightening is controlled to obtain steel for hydrogen pipelines.

[0049] In some embodiments, the reduction amount of the thermal straightening includes: setting the inlet reduction amount and the outlet reduction amount of the straightening roller, respectively; wherein,

[0050] The inlet reduction of the first 7 straightening rollers is 3-4 mm, and the outlet reduction of the first 7 straightening rollers is 0.4-0.8 mm.

[0051] The inlet pressure of the last four straightening rollers is 1.0 to 1.5 mm, and the outlet pressure of the last four straightening rollers is 0 to 0.2 mm.

[0052] The positive effects of setting the inlet and outlet reduction amounts of the straightening rollers are: effectively eliminating and releasing residual stress inside the steel plate, thereby significantly improving the dimensional accuracy of the steel plate shape. Specifically, the inlet reduction amount of the first 7 straightening rollers can be 3mm, 4mm, etc., and the outlet reduction amount of the first 7 straightening rollers can be 0.4mm, 0.6mm, 0.8mm, etc.; the inlet reduction amount of the last 4 straightening rollers can be 1.0mm, 1.3mm, 1.5mm, etc., and the outlet reduction amount of the last 4 straightening rollers can be 0.1mm, 0.2mm, etc.

[0053] Secondly, this application provides a steel for hydrogen pipelines, which is prepared by the method described in any embodiment of the first aspect.

[0054] The steel for hydrogen pipelines is based on the above-described preparation method for hydrogen pipelines. The specific steps of the preparation method can be referred to in the above embodiments. Since the steel for hydrogen pipelines adopts some or all of the technical solutions of the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be elaborated here.

[0055] The present application is further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the application. Experimental methods in the following embodiments that do not specify specific conditions are generally determined according to national standards. If there is no corresponding national standard, then general international standards, conventional conditions, or conditions recommended by the manufacturer are followed.

[0056] Example 1

[0057] Hot rolling is carried out on a heavy plate production line. First, the slab is heated, and then rough rolling, fine rolling, pre-straightening, cooling and hot straightening are performed in sequence to obtain 10.8mm L360MH hot-rolled steel plate.

[0058] The billet heating process is controlled as follows: heating temperature 1175℃, heating time 255min.

[0059] The billet roughing process is controlled as follows: the roughing temperature starts at 1060℃. During the longitudinal rolling stage of the billet roughing, high-pressure descaling water is sprayed in each pass to rapidly cool the surface of the billet, and the surface temperature drops by 41-50℃ instantaneously. At the same time, the rolling temperature is controlled at 965-975℃ in the last three passes of the longitudinal rolling, and the single-pass reduction rate is controlled at 26-33%.

[0060] The finishing rolling process of the billet is controlled as follows: the starting temperature of finishing rolling is 940℃, the finishing rolling temperature is 865℃, and the reduction of the last two passes is controlled to be 1.15mm and 1.0mm respectively.

[0061] The pre-straightening process of steel plates is controlled as follows: the inlet pressure of the pre-straightening machine is 2.5mm, and the bite speed is 0.75m / s.

[0062] The hot straightening process of steel plates is controlled as follows: the inlet pressure of the first 7 straightening rollers is 3.2mm and the outlet pressure is 0.5mm; the inlet pressure of the last 4 straightening rollers is 1mm and the outlet pressure is 0.1mm.

[0063] Comparative Example 1

[0064] Hot rolling is carried out on a heavy plate production line. First, the slab is heated, and then rough rolling, fine rolling, cooling and hot straightening are performed in sequence to obtain 10.8mm L360MH hot-rolled steel plate.

[0065] The billet heating process is controlled as follows: heating temperature 1175℃, heating time 255min.

[0066] The roughing process control for steel billets is as follows: the starting temperature for roughing is 1060℃, and the ending temperature is 1030℃.

[0067] The finishing rolling process for steel billets is controlled as follows: the starting temperature for finishing rolling is 940℃, and the final rolling temperature is 865℃.

[0068] The hot straightening process for steel plates is controlled as follows: inlet reduction 1.8mm, outlet reduction 0.25mm.

[0069] Example 2

[0070] Hot rolling is carried out on a heavy plate production line. First, the slab is heated, and then rough rolling, fine rolling, pre-straightening, cooling and hot straightening are performed in sequence to obtain 13.2mm L290MH hot-rolled steel plate.

[0071] The billet heating process is controlled as follows: heating temperature 1170℃, heating time 240min.

[0072] The billet roughing process is controlled as follows: the roughing temperature starts at 1050℃. During the longitudinal rolling stage of the billet roughing, high-pressure descaling water is sprayed in each pass to rapidly cool the surface of the billet, and the surface temperature drops by 43-52℃ instantaneously. At the same time, the rolling temperature is controlled at 970-980℃ in the last three passes of the longitudinal rolling, and the single-pass reduction rate is controlled at 28-33%.

[0073] The billet finishing rolling process is controlled as follows: the finishing rolling start temperature is 930℃, the finishing rolling temperature is 860℃, and the reduction of the last two passes is controlled to be 1.4mm and 1.2mm respectively.

[0074] The pre-straightening process of steel plates is controlled as follows: the inlet pressure of the pre-straightening machine is 2.7mm, and the bite speed is 0.8m / s.

[0075] The hot straightening process of steel plates is controlled as follows: the inlet pressure of the first 7 straightening rollers is 3.5mm and the outlet pressure is 0.6mm; the inlet pressure of the last 4 straightening rollers is 1.2mm and the outlet pressure is 0.15mm.

[0076] Comparative Example 2

[0077] Hot rolling is carried out on a heavy plate production line. First, the slab is heated, and then rough rolling, fine rolling, cooling and hot straightening are performed in sequence to obtain 13.2mm L290MH hot-rolled steel plate.

[0078] The billet heating process is controlled as follows: heating temperature 1170℃, heating time 240min.

[0079] The roughing process control for billets is as follows: the starting temperature for roughing is 1050℃, and the ending temperature is 1025℃.

[0080] The finishing rolling process for steel billets is controlled as follows: the starting temperature for finishing rolling is 930℃, and the final rolling temperature is 860℃.

[0081] The hot straightening process for steel plates is controlled as follows: inlet reduction 2.2mm, outlet reduction 0.35mm.

[0082] Example 3

[0083] Hot rolling is carried out on a heavy plate production line. First, the slab is heated, and then rough rolling, fine rolling, pre-straightening, cooling and hot straightening are performed in sequence to obtain 15.9mm L245MH hot-rolled steel plate.

[0084] The billet heating process is controlled as follows: heating temperature 1180℃, heating time 245min.

[0085] The billet roughing process is controlled as follows: the roughing start temperature is 1070℃. During the longitudinal rolling stage of the billet roughing, high-pressure descaling water is sprayed in each pass to rapidly cool the surface of the billet, and the surface temperature drops by 42-50℃ instantaneously. At the same time, the rolling temperature is controlled at 975-980℃ in the last three passes of the longitudinal rolling, and the single-pass reduction rate is controlled at 27-35%.

[0086] The billet finishing rolling process is controlled as follows: the finishing rolling start temperature is 945℃, the finishing rolling temperature is 850℃, and the reduction of the last two passes is controlled to be 1.5mm and 1.2mm respectively.

[0087] The pre-straightening process of steel plates is controlled as follows: the inlet pressure of the pre-straightening machine is 2.8mm, and the bite speed is 0.95m / s.

[0088] The hot straightening process of steel plates is controlled as follows: the inlet pressure of the first 7 straightening rollers is 3.85mm and the outlet pressure is 0.7mm; the inlet pressure of the last 4 straightening rollers is 1.4mm and the outlet pressure is 0.2mm.

[0089] Comparative Example 3

[0090] Hot rolling is carried out on a heavy plate production line. First, the slab is heated, and then rough rolling, fine rolling, cooling and hot straightening are performed in sequence to obtain 15.9mm L245MH hot-rolled steel plate.

[0091] The billet heating process is controlled as follows: heating temperature 1180℃, heating time 245min.

[0092] The roughing process control for billets is as follows: the starting temperature for roughing is 1070℃, and the ending temperature is 1030℃.

[0093] The finishing rolling process for steel billets is controlled as follows: the starting temperature for finishing rolling is 945℃, and the final rolling temperature is 850℃.

[0094] The hot straightening process for steel plates is controlled as follows: inlet reduction 2.5mm, outlet reduction 0.37mm.

[0095] The mechanical properties and dimensions of the rolled steel plates from Examples 1-3 and Comparative Examples 1-3 were tested, and the statistical results are shown in Table 1.

[0096]

[0097]

[0098] The hydrogen pipeline steel prepared by the method of this application meets the user's requirements in terms of comprehensive performance. However, the comparative example did not adopt the method of the embodiment of this application, and the mechanical properties and plate size of the steel plate are worse than those of the embodiment.

[0099] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for preparing steel for hydrogen pipelines, characterized in that, The method includes: The steel billet is rough rolled to obtain an intermediate billet; wherein the rough rolling includes a longitudinal rolling stage, and the process parameters of each pass of the longitudinal rolling are controlled. The intermediate billet is precision rolled, and the reduction amount of the precision rolling is controlled to obtain a hot-rolled plate; The hot-rolled plate is pre-straightened, and the process parameters for pre-straightening are controlled, followed by cooling. The cooled hot-rolled plate is hot-straightened, and the reduction amount of the hot straightening is controlled to obtain steel for hydrogen pipelines; The process parameters for each pass of the longitudinal rolling process include: Water-based rolling mode, rolling temperature of the last three passes of longitudinal rolling, and single reduction rate of the last three passes of longitudinal rolling; The water usage pattern is as follows: each rolling pass of the longitudinal rolling process is sprayed with high-pressure descaling water to cool the surface of the steel billet. The rolling temperature for the last three passes of the longitudinal rolling is 960~980℃; The single reduction rate of the last three passes of the longitudinal rolling is 25-35%; The reduction amount of the finishing mill includes: the reduction amount of the last two passes of the finishing mill is 1.0~1.5mm; The pre-straightening process parameters include: pre-straightening inlet depressurization, pre-straightening outlet depressurization, and pre-straightening bite speed; The pre-straightening inlet depressurization is 2.5~3.0mm, the pre-straightening outlet depressurization is 0.6~0.8mm, and the pre-straightening bite speed is 0.7~1.0m / s; The reduction amount in the thermal straightening includes: setting the inlet reduction amount and the outlet reduction amount of the straightening roller, respectively; wherein, The inlet reduction of the first 7 straightening rollers is 3~4mm, and the outlet reduction of the first 7 straightening rollers is 0.4~0.8mm; The inlet pressure of the last four straightening rollers is 1.0~1.5mm, and the outlet pressure of the last four straightening rollers is 0~0.2mm.

2. A type of steel for hydrogen pipelines, characterized in that, The steel used for the hydrogen pipeline is prepared by the method described in claim 1.

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