Steel for pure hydrogen conveying pipeline and preparation method thereof

Abstract

The invention relates to steel for a pure hydrogen conveying pipeline and a preparation method of the steel. The steel for the pure hydrogen conveying pipeline comprises the chemical components of C, Si, Mn, P, S, Nb, Cr, RE and Fe. Wherein the content of C is 0.030%-0.070% by mass, the content of Si is smaller than or equal to 0.20% by mass, the content of Mn is 0.85%-1.25% by mass, the content of P is smaller than or equal to 0.0150% by mass, the content of S is smaller than or equal to 0.0020% by mass, the content of RE is 0.0030%-0.0100% by mass, the content of Nb is 0.010%-0.040% by mass, and the content of Cr is smaller than or equal to 0.30% by mass. The fatigue life of the steel for the pure hydrogen conveying pipeline is prolonged, and the fatigue life of a smooth sample can be prolonged to 300,000 times in a 6.3 MPa gaseous hydrogen charging environment.

Description

Technical Field

[0001] The present application relates to the technical field of steel preparation, and in particular to a steel for a pure hydrogen transmission pipeline and a preparation method thereof. Background Art

[0002] At present, hydrogen energy storage and transportation mainly serve short-distance transportation within the region. In the future, there will be a large demand for medium and long-distance storage and transportation. Pipeline transportation of pure hydrogen or hydrogen-blended hydrogen is the last mile to connect hydrogen production and use.

[0003] The existing hydrogen pipeline pipe manufacturing method determines the indispensability of hot rolling to produce coils. However, the fatigue life of steel for pure hydrogen transmission pipelines produced by hot rolling is relatively low, making it difficult to meet the needs of medium and long-distance hydrogen storage and transportation. Summary of the invention

[0004] The present application provides a steel for a pure hydrogen transmission pipeline and a preparation method thereof to solve the following technical problem: how to improve the fatigue life of the steel for a pure hydrogen transmission pipeline.

[0005] In a first aspect, the present application provides a steel for a pure hydrogen transportation pipeline, the chemical composition of the steel for a pure hydrogen transportation pipeline comprising:

[0006] C, Si, Mn, P, S, Nb, Cr, RE and Fe; among them, in terms of mass fraction,

[0007] The content of C is 0.030% to 0.070%, the content of Si is ≤ 0.20%, the content of Mn is 0.85% to 1.25%, and the content of P is

[0008] ≤0.0150%, S content ≤0.0020%, RE content 0.0030%~0.0100%.

[0009] Optionally, the Nb content is 0.010% to 0.040%, and the Cr content is ≤0.30%.

[0010] Optionally, the C content is 0.030% to 0.060%, the Si content is ≤0.15%, the Mn content is 0.90% to 1.1%, the P content is ≤0.0120%, the S content is ≤0.0010%, the Nb content is 0.010% to 0.020%, the Cr content is ≤0.20%, and the RE content is 0.0040% to 0.0080%.

[0011] Optionally, the RE includes at least one of the following: La, Ce.

[0012] Optionally, the microstructure of the steel for pure hydrogen transportation pipeline includes ferrite and pearlite.

[0013] Optionally, the steel grade of the pure hydrogen transportation pipeline meets L245 or L360.

[0014] In a second aspect, the present application provides a method for preparing the steel for a pure hydrogen transportation pipeline according to the first aspect, the method comprising:

[0015] Heating the slab and controlling the heating temperature;

[0016] Rolling the heated slab and controlling the final rolling temperature of the rolling to obtain a hot-rolled plate;

[0017] The hot rolled plate is cooled and then coiled, and the coiling temperature is controlled to obtain steel for pure hydrogen transport pipeline.

[0018] Optionally, the heating temperature is 1160°C to 1250°C.

[0019] Optionally, the final rolling temperature is 830°C to 900°C.

[0020] Optionally, the coiling temperature is 500°C to 600°C.

[0021] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0022] The steel for pure hydrogen transportation pipeline provided in the embodiment of the present application has a C content of 0.030% to 0.070% and a Si content of

[0023] ≤0.20%, Mn content 0.85%~1.25%, P content ≤0.0150% and S content ≤0.0020% under the synergistic effect of the chemical composition combination, can reduce the difficulty of controlling the central segregation of steel, and improve the purity of steel, thereby improving the fatigue life of steel; RE has strong oxidizing properties, which plays an important role in the deoxidation, desulfurization, inclusion denaturation, and improving the strength and toughness of steel. In the numerical range of RE content 0.0030%~0.0100%, the inclusions in the steel can be fully modified, thereby achieving the purpose of purifying the steel and further improving the fatigue life of the steel. In summary, the fatigue life of steel for pure hydrogen transmission pipelines is improved. In a 6.3MPa gaseous hydrogen filling environment, the fatigue life of the smooth sample can be increased to 300,000 times. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0025] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0026] Figure 1 A microstructure diagram of steel for a pure hydrogen transport pipeline provided according to some embodiments of the present application;

[0027] Figure 2 The present invention is a schematic flow chart of a method for preparing steel for a pure hydrogen transportation pipeline according to some embodiments of the present application. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0029] Various embodiments of the present application may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be understood as a rigid limitation on the scope of the present application; therefore, the range description should be considered to have specifically disclosed all possible sub-ranges and single numerical values ​​within the range. For example, the range description from 1 to 6 should be considered to have 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., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which apply regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any cited number (fractional or integer) within the indicated range.

[0030] In this application, the terms "include", "comprising", etc. mean "including but not limited to". In this article, "at least one" means one or more, and "plurality" 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 items or plural items. For example, "at least one of a, b, or c", or "at least one of a, b, and c" can all mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, c can be single or multiple, respectively.

[0031] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0032] The present application provides a steel for a pure hydrogen transportation pipeline, the chemical composition of the steel for a pure hydrogen transportation pipeline comprising:

[0033] C, Si, Mn, P, S, Nb, Cr, RE and Fe; among them, in terms of mass fraction,

[0034] The C content is 0.030% to 0.070%, the Si content is ≤0.20%, the Mn content is 0.85% to 1.25%, the P content is ≤0.0150%, the S content is ≤0.0020%, and the RE content is 0.0030% to 0.0100%.

[0035] In the embodiment of the present application, the chemical composition combination of low C, low Mn, ultra-low P and ultra-low S can reduce the difficulty of controlling the center segregation of steel and improve the purity of steel, thereby improving the fatigue life of steel; RE (rare earth elements) have strong oxidizing properties and can modify the inclusions in steel, thereby achieving the purpose of purifying steel and further improving the fatigue life of steel. When the addition amount of RE (rare earth elements) is too low, it is difficult to achieve the purpose of purifying steel; when the addition amount is too high, the rare earth oxide inclusions formed are difficult to float up, forming a large number of inclusions and deteriorating the mechanical properties of the material. For example, the C content may be 0.030%, 0.050%, 0.070%, etc.; the Si content may be 0.20%, 0.18%, 0.16%, 0.14%, etc.; the Mn content may be 0.85%, 0.90%, 0.95%, 1.0%, 1.1%, 1.15%, 1.2%, 1.25%, etc.; the P content may be 0.0150%, 0.020%, 0.030%, 0.050%, 0.070%, etc.; the Si content may be 0.20%, 0.18%, 0.16%, 0.14%, etc.; the Mn content may be 0.85%, 0.90%, 0.95%, 1.0%, 1.1%, 1.15%, 1.2%, 1.25%, etc. .0140%, 0.0130%, 0.0120%, etc.; the S content may be 0.0020%, 0.0015%, 0.0016%, 0.0017%, 0.0018%, etc.; the RE content may be 0.0030%, 0.0040%, 0.0050%, 0.0060%, 0.0070%, 0.0080%, 0.0090%, 0.010%, etc.

[0036] In some embodiments, the content of Nb is 0.010% to 0.040%, and the content of Cr is ≤0.30%.

[0037] In the embodiment of the present application, Nb and Cr are further added to further compensate for the strength of the steel. For example, the content of Nb can be 0.010%, 0.020%, 0.030%, 0.040%, etc.; the content of Cr can be 0.30%, 0.25%, 0.20%, 0.15%, etc.

[0038] In some embodiments, the C content is 0.030% to 0.060%, the Si content is ≤0.15%, the Mn content is 0.90% to 1.1%, the P content is ≤0.0120%, the S content is ≤0.0010%, the Nb content is 0.010% to 0.020%, the Cr content is ≤0.20%, and the RE content is 0.0040% to 0.0080%.

[0039] In the embodiments of the present application, further, as some of the preferred embodiments, the C content may be 0.030% to 0.060%, the Si content may be ≤0.15%, the Mn content may be 0.90% to 1.1%, the P content may be ≤0.0120%, the S content may be ≤0.0010%, the Nb content may be 0.010% to 0.020%, the Cr content may be ≤0.20%, and the RE content may be 0.0040% to 0.0080%.

[0040] In some embodiments, the RE includes at least one of the following: La, Ce.

[0041] In the embodiment of the present application, the RE may be one of La and Ce, or a mixture.

[0042] In some embodiments, the microstructure of the steel for a pure hydrogen transportation pipeline includes ferrite and pearlite.

[0043] In some embodiments, the steel grade of the pure hydrogen transport pipeline meets L245 or L360.

[0044] In the embodiments of the present application, Figure 1 A microstructure diagram of a steel for a pure hydrogen transport pipeline provided according to some embodiments of the present application; see Figure 1 The microstructure is ferrite and pearlite, and the uniformity of the structure is good. The steel grade of the pure hydrogen pipeline can meet L245 or L360.

[0045] Figure 2 The following is a schematic diagram of a method for preparing steel for a pure hydrogen transmission pipeline according to some embodiments of the present application. Figure 2The present application provides a method for preparing steel for a pure hydrogen transportation pipeline according to the first aspect, the method comprising:

[0046] S1, heating the slab and controlling the heating temperature;

[0047] In some embodiments, the heating temperature is 1160°C to 1250°C.

[0048] In the embodiment of the present application, the heating temperature is limited, the high temperature uniforms the composition of the slab and prepares for the subsequent rolling process to ensure that the slab is fully austenitized. If the heating temperature is too high, it may cause the slab surface to have a thicker iron oxide scale, which is not conducive to the descaling of the strip surface and affects the surface quality of the finished strip; if the heating temperature is too low, the slab may not be heated sufficiently, and it is difficult to ensure the dynamic recrystallization process of the rolling process. Exemplarily, the above-mentioned heating temperature can be 1160℃, 1170℃, 1180℃, 1190℃, 1200℃, 1210℃, 1220℃, 1230℃, 1240℃, 1250℃, etc. The above-mentioned heating time in the furnace is ≥180min, so that the slab is fully austenitized and the composition of the slab is further uniform. It avoids the problem that the time is too short, the slab is not homogenized enough, and it is easy to have banded structure defects in the subsequent rolling process; and the time is too long, which is easy to cause more iron oxide scale on the slab surface and abnormal enlargement of austenite grains.

[0049] S2, rolling the heated slab and controlling the final rolling temperature of the rolling to obtain a hot-rolled plate;

[0050] In some embodiments, the final rolling temperature of the rolling is 830°C to 900°C.

[0051] In the embodiment of the present application, rolling includes rough rolling and finishing rolling, and the final rolling temperature of rolling is the final rolling temperature of finishing rolling. The final rolling temperature of finishing rolling is limited, and the finishing rolling process is controlled to be rolled in the non-recrystallization zone to facilitate subsequent cooling. Exemplarily, the final rolling temperature of the above rolling can be 830°C, 840°C, 850°C, 860°C, 870°C, 880°C, 890°C, 900°C, etc.

[0052] S3, cooling the hot-rolled plate, and then coiling it, and controlling the coiling temperature to obtain steel for pure hydrogen transportation pipeline.

[0053] In some embodiments, the coiling temperature is 500°C to 600°C.

[0054] In the embodiment of the present application, the coiling temperature is limited to ensure the mechanical properties of the steel for pure hydrogen transmission pipeline. Exemplarily, the coiling temperature can be 500°C, 510°C, 520°C, 530°C, 540°C, 550°C, 560°C, 570°C, 580°C, 590°C, 600°C, etc. The cooling is laminar cooling, and the front-stage laminar cooling mode is used for cooling.

[0055] The preparation method of the steel for pure hydrogen transportation pipeline is realized based on the chemical composition of the above-mentioned steel for pure hydrogen transportation pipeline. The specific chemical composition of the steel for pure hydrogen transportation pipeline can refer to the above-mentioned embodiment. Since the preparation method of the steel for pure hydrogen transportation pipeline adopts part or all of the technical solutions of the above-mentioned embodiment, it at least has all the beneficial effects brought by the technical solutions of the above-mentioned embodiment, which will not be repeated here one by one.

[0056] The present application will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are intended only to illustrate the present application and are not intended to limit the scope of the present application. The experimental methods for which specific conditions are not specified in the following examples are usually measured according to national standards. If there is no corresponding national standard, then the conditions recommended by the manufacturer are followed.

[0057] Example 1

[0058] A steel for pure hydrogen transmission pipeline, whose chemical composition is calculated by weight percentage: C: 0.03%, Si: 0.18%, Mn: 1.25%, P: 0.0094%, S: 0.0005%, Nb: 0.040%, Cr: 0.15%, La+Ce: 0.0050%, and the rest is Fe and unavoidable impurities.

[0059] A method for preparing steel for a pure hydrogen transmission pipeline includes: molten iron pretreatment, converter smelting, refining, continuous casting, and hot rolling. The hot rolling furnace temperature is controlled at 1240°C, and the furnace time is 220 minutes; the final rolling temperature of the fine rolling is controlled at 880°C; after rolling, the steel is cooled to 600°C by a front-end cooling process and coiled to obtain a finished product.

[0060] Example 2

[0061] A steel for pure hydrogen transmission pipeline, the chemical composition of which is calculated by weight percentage: C: 0.05%, Si: 0.20%, Mn: 0.85%, P: 0.0050%, S: 0.0010%, Nb: 0.020%, Cr: 0.15%, La+Ce: 0.0030%, and the rest is Fe and unavoidable impurities.

[0062] A method for preparing steel for a pure hydrogen transmission pipeline includes: molten iron pretreatment, converter smelting, refining, continuous casting, and hot rolling. The hot rolling furnace temperature is controlled at 1180°C, and the furnace time is 220 minutes; the final rolling temperature of the fine rolling is controlled at 880°C; after rolling, the steel is cooled to 550°C by a front-end cooling process and coiled to obtain a finished product.

[0063] Example 3

[0064] A steel for pure hydrogen transmission pipeline, the chemical composition of which is calculated by weight percentage: C: 0.03%, Si: 0.18%, Mn: 0.85%, P: 0.0064%, S: 0.0005%, Nb: 0.010%, La+Ce: 0.010%, and the rest is Fe and unavoidable impurities.

[0065] A method for preparing steel for a pure hydrogen transmission pipeline includes: molten iron pretreatment, converter smelting, refining, continuous casting, and hot rolling. The hot rolling furnace temperature is controlled at 1200°C, and the furnace time is 180 minutes; the final rolling temperature of the fine rolling is controlled at 900°C; after rolling, the steel is cooled to 500°C by a front-end cooling process and coiled to obtain a finished product.

[0066] Comparative Example 1

[0067] A steel for pure hydrogen transmission pipeline, the chemical composition of which is calculated by weight percentage: C: 0.03%, Si: 0.18%, Mn: 1.25%, P: 0.0094%, S: 0.0005%, Nb: 0.040%, Cr: 0.15%, and the rest is Fe and unavoidable impurities.

[0068] A method for preparing steel for a pure hydrogen transmission pipeline includes: molten iron pretreatment, converter smelting, refining, continuous casting, and hot rolling. The hot rolling furnace temperature is controlled at 1240°C, and the furnace time is 220 minutes; the final rolling temperature of the fine rolling is controlled at 880°C; after rolling, the steel is cooled to 600°C by a front-end cooling process and coiled to obtain a finished product.

[0069] A fatigue life test was performed on the steel for pure hydrogen transmission pipeline prepared in Examples 1 to 3 and Comparative Example 1, and the steps included: the test method referred to GB / T 34542-2018 "Test method for compatibility of metal materials with hydrogen environment", and a fatigue life test of a smooth specimen was performed in a 6.3 MPa hydrogen environment. The test frequency was 0.1 Hz to 1 Hz, and the loading load was the minimum yield strength specified in the material standard.

[0070] When the fatigue number of the smooth sample of the finished product of the steel for pure hydrogen transportation pipeline obtained in Example 1 was 300,000 times in a 6.3MPa pure hydrogen environment, no cracks were found in the fatigue sample, indicating that the fatigue life is >300,000 times.

[0071] When the fatigue number of the smooth sample of the finished product of the pure hydrogen transportation pipeline steel obtained in Example 2 was 300,000 times in a 6.3MPa pure hydrogen environment, no cracks were found in the fatigue sample, indicating that the fatigue life is >300,000 times.

[0072] When the fatigue number of the smooth sample of the finished product of the pure hydrogen transportation pipeline steel obtained in Example 3 was 300,000 times in a 6.3MPa pure hydrogen environment, no cracks were found in the fatigue sample, indicating that the fatigue life is >300,000 times.

[0073] The finished product of the steel for pure hydrogen transportation pipeline obtained in Comparative Example 1 broke when the fatigue number of the smooth sample reached 153,000 times in a 6.3 MPa pure hydrogen environment.

[0074] In summary, the steel for pure hydrogen transmission pipeline provided in this application can increase the fatigue life of smooth specimens to 300,000 times in a 6.3MPa gaseous hydrogen filling environment.

[0075] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A steel for pure hydrogen transportation pipeline, characterized in that: The chemical composition of the steel for pure hydrogen transportation pipeline includes: C, Si, Mn, P, S, Nb, Cr, RE and Fe; among them, in terms of mass fraction, The C content is 0.030% to 0.070%, the Si content is ≤0.20%, the Mn content is 0.85% to 1.25%, the P content is ≤0.0150%, the S content is ≤0.0020%, and the RE content is 0.0030% to 0.0100%.

2. The steel for pure hydrogen transportation pipeline according to claim 1, characterized in that: The content of Nb is 0.010% to 0.040%, and the content of Cr is ≤0.30%.

3. The steel for pure hydrogen transportation pipeline according to claim 2, characterized in that: The C content is 0.030% to 0.060%, the Si content is ≤0.15%, the Mn content is 0.90% to 1.1%, the P content is ≤0.0120%, the S content is ≤0.0010%, the Nb content is 0.010% to 0.020%, the Cr content is ≤0.20%, and the RE content is 0.0040% to 0.0080%.

4. The steel for pure hydrogen transportation pipeline according to claim 1, characterized in that: The RE includes at least one of the following: La, Ce.

5. The steel for pure hydrogen transportation pipeline according to any one of claims 1 to 4, characterized in that: The microstructure of the steel for pure hydrogen transportation pipeline includes ferrite and pearlite.

6. The steel for pure hydrogen transportation pipeline according to claim 5, characterized in that: The steel grade of the pure hydrogen transportation pipeline meets L245 or L360.

7. A method for preparing steel for pure hydrogen transportation pipeline according to any one of claims 1 to 6, characterized in that: The method comprises: Heating the slab and controlling the heating temperature; Rolling the heated slab and controlling the final rolling temperature of the rolling to obtain a hot-rolled plate; The hot rolled plate is cooled and then coiled, and the coiling temperature is controlled to obtain steel for pure hydrogen transport pipeline.

8. The method according to claim 7, characterized in that The heating temperature is 1160°C to 1250°C.

9. The method according to claim 7, characterized in that: The final rolling temperature of the rolling is 830°C to 900°C.

10. The method according to claim 7, characterized in that The coiling temperature is 500°C to 600°C.

Images