Production method of hot rolled steel coil for supercritical carbon dioxide conveying pipeline

Abstract

The invention discloses a hot rolled steel coil for a supercritical carbon dioxide conveying pipeline and a production method of the hot rolled steel coil. The steel coil comprises the following chemical components in percentage by weight: 0.03 to 0.05 percent of C, 0.10 to 0.30 percent of S i, 1.20 to 1.40 percent of Mn, less than or equal to 0.010 percent of P, less than or equal to 0.002 percent of S, 0.030 to 0.050 percent of Nb, 0.005 to 0.020 percent of T i, 0.20 to 0.40 percent of Cr, 0.10 to 0.25 percent of N i, 0.020 to 0.050 percent of Al and the balance of Fe and inevitable impurities. The Nb-Ti-Cr-Ni alloy components and the TMCP rolling technology are adopted, the thickness of a steel coil is 10-15 mm, the steel coil has good strength, low-temperature toughness and carbon dioxide corrosion resistance, the impact energy at the temperature of-60 DEG C is larger than 300 J, the corrosion rate is smaller than 0.125 mm / a, and the requirement for the steel for the supercritical carbon dioxide conveying pipeline is completely met.

Description

Technical Field

[0001] The invention belongs to the technical field of iron and steel metallurgy, and in particular relates to a production method of a hot-rolled steel coil for a supercritical carbon dioxide transmission pipeline. Background Art

[0002] CO2 transportation is one of the important links in the CCUS industry chain and is the key link between carbon sources and carbon sinks. CO2 transportation methods are mainly divided into three types: pipeline transportation, ship transportation and tank truck transportation. For large-scale and long-distance transportation tasks, pipeline transportation has obvious advantages such as safety, environmental protection and economy. In the future, carbon dioxide transportation pipelines will have a good application prospect. Supercritical CO2 has a density close to that of liquid and a viscosity close to that of gas. It has the characteristics of high density and low viscosity, and has low friction along the way. Therefore, supercritical CO2 pipeline transportation is the most economical and efficient transportation method.

[0003] Patent CN 111218624 B discloses a seamless steel pipe resistant to carbon dioxide corrosion and its preparation method, in which the Cr content is 5.5-8.5% and the Ni content is 0.1-2.0%; Patent CN 103334055 B discloses a pipeline steel resistant to carbon dioxide and hydrogen sulfide corrosion and its production method, in which the Cr content is 2.0-6.0% and the Ni content is ≤0.3%. The alloy content in the above patents is relatively high, which makes it difficult to add alloys during the smelting process, increases the difficulty of smelting, and causes high costs. In addition, the steel used for carbon dioxide transmission pipelines currently retrieved is basically seamless pipes, which are produced by high alloy component design and quenching and tempering treatment, with high alloy content, long process flow, high alloy cost and process cost, and great limitations on pipe diameter and application conditions. Summary of the invention

[0004] The purpose of the present invention is to provide a production method of a hot-rolled steel coil for a supercritical carbon dioxide transmission pipeline. The steel coil has a thickness of 10-15 mm, adopts Nb-Ti-Cr-Ni alloy composition and TMCP rolling process, has good strength, low-temperature toughness and carbon dioxide corrosion resistance, and meets the requirements of steel for supercritical carbon dioxide transmission pipelines.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] The invention discloses a production method of a hot-rolled steel coil for a supercritical carbon dioxide transmission pipeline. The smelting adopts LF+RH double refining, and the gas and inclusion contents are strictly controlled; the inclusions of A, B, C, D, and DS are all not greater than 1.5 level, and the total inclusions are less than 4.0 level; the continuous casting adopts dynamic soft pressure reduction and electromagnetic stirring, and the quality of the casting reaches Class C 1.0 level; after continuous casting, the slab is placed for at least 48 hours before hot rolling, and the slab heating temperature is 1160-1200°C, and the heating time is 200- 300min, the heating time should not be too long to prevent surface oxidation; the rolling adopts two-stage rolling of rough rolling and finishing rolling, the rough rolling adopts two stands, the starting rolling temperature is ≥1100℃, the rough rolling pass adopts a large reduction rate, and the cumulative reduction rate is 78%-83%; the finishing rolling adopts seven-stand continuous rolling, the starting rolling temperature is ≤980℃, the finishing rolling cumulative reduction rate is 70%-75%, and the final rolling temperature is 820-860℃; after rolling, the steel coil is coiled after cooling to 600-640℃;

[0007] The chemical composition of the hot-rolled steel coil for supercritical carbon dioxide delivery pipeline is C: 0.03-0.05%, Si: 0.10-0.30%, Mn: 1.20-1.40%, P: ≤0.010%, S: ≤0.002%, Nb: 0.030-0.050%, Ti: 0.005-0.020%, Cr: 0.20-0.40%, Ni: 0.10-0.25%, Al: 0.020-0.050%, and the balance is Fe and unavoidable impurities.

[0008] Furthermore, the microstructure is fine ferrite and a small amount of pearlite, the product has excellent comprehensive performance, and the impact energy at -60℃ is greater than 300J.

[0009] Furthermore, a carbon dioxide environment corrosion test was carried out using an autoclave, and the product had good resistance to carbon dioxide corrosion.

[0010] Furthermore, the chemical composition of the hot-rolled steel coil for the supercritical carbon dioxide delivery pipeline is C: 0.04%, Si: 0.20%, Mn: 1.30%, P: 0.007%, S: 0.0015%, Nb: 0.040%, Ti: 0.015%, Cr: 0.30%, Ni: 0.15%, Al: 0.035%, and the balance is Fe and unavoidable impurities.

[0011] Furthermore, the chemical composition of the hot-rolled steel coil for the supercritical carbon dioxide delivery pipeline is C: 0.05%, Si: 0.15%, Mn: 1.25%, P: 0.006%, S: 0.0012%, Nb: 0.045%, Ti: 0.010%, Cr: 0.35%, Ni: 0.25%, Al: 0.035%, and the balance is Fe and unavoidable impurities.

[0012] Furthermore, the chemical composition of the hot-rolled steel coil for the supercritical carbon dioxide delivery pipeline is C: 0.05%, Si: 0.25%, Mn: 1.40%, P: 0.008%, S: 0.0020%, Nb: 0.035%, Ti: 0.018%, Cr: 0.25%, Ni: 0.20%, Al: 0.040%, and the balance is Fe and unavoidable impurities.

[0013] Compared with the prior art, the beneficial technical effects of the present invention are:

[0014] (1) The composition is designed with low C and Nb-Ti-Cr-Ni to ensure that the product has good strength, low temperature toughness and carbon dioxide corrosion resistance. The C element is easy to cause central segregation, resulting in an increase in the proportion of pearlite in the structure, an increase in the exposed Fe3C area, an increase in the area ratio between the cathode and the anode, and an increase in the corrosion rate. Therefore, a low C content is used. The Cr element can effectively improve the CO2 corrosion resistance of steel. Since the Cr element can change the composition and structure of the CO2 corrosion product film, increase the density of the corrosion product film, reduce the conductivity of the corrosion product film, hinder the corrosive anions in the medium, and enhance the protectiveness of the metal matrix. The Ni element reduces the corrosion rate of steel by increasing the matrix potential, and at the same time can increase the strength of the steel to make up for the strength loss caused by the low C content. The addition of Nb and Ti elements can not only refine the grains, but also fix C and N to reduce the precipitation of Cr carbon and nitrides. The Cr element is distributed in solid solution along the grain boundaries, increasing the uniformity of Cr distribution and improving the efficiency of Cr. The grain size of the steel reaches level 11, which improves the strength and low temperature toughness of the steel.

[0015] (2) Material factors such as ingot quality, inclusions and banded structure have an impact on the corrosion failure of steel. The ingot quality is controlled at C1.0 level. Combined with the TMCP process and low-temperature and high-pressure rolling, the banded structure is controlled to be no more than 1.0 level, thereby reducing stress concentration at the banded structure and controlling the formation and expansion of corrosion. Deep desulfurization and increased soft blowing time are used to reduce the S and inclusion content, the inclusion is no more than 1.5 level, and the total inclusion is less than 4.0 level, thereby preventing inclusion-induced pitting corrosion.

[0016] (3) Hot-rolled steel coil welded pipes are used instead of seamless steel pipes. Compared with seamless steel pipes, steel coils have high dimensional accuracy, good surface quality, good product quality control, and more uniform performance; the composition and structure of the weld of hot-rolled steel coil welded pipes and the C, P, and S content in the matrix material are lower, making the toughness of the weld better than that of seamless casing, while improving the anti-extrusion and anti-explosion properties; the use of hot-rolled steel coils has high production efficiency and yield rate, and the production cost is about 10% lower. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present invention will be further described below in conjunction with the accompanying drawings.

[0018] Figure 1 This is the metallographic structure of Example 1 of the present invention;

[0019] Figure 2 This is the impact energy of Example 1 of the present invention. DETAILED DESCRIPTION

[0020] The present invention will be further described in detail below in conjunction with specific examples. These examples are merely descriptions of the best mode of carrying out the present invention and do not limit the scope of the present invention in any way.

[0021] Examples 1-3 are the chemical compositions and process steps used in the hot-rolled steel coils for supercritical carbon dioxide delivery pipelines of the present invention with a thickness of 10-15 mm, and the comparative example is the chemical composition and process steps used in the seamless steel pipe resistant to carbon dioxide corrosion. The chemical compositions of the embodiments and comparative examples are shown in Table 1.

[0022] Table 1 Chemical composition of each embodiment and comparative example (wt%)

[0023]

[0024]

[0025] The process parameters of Examples 1-3 are shown in Table 2; the process parameters of Comparative Examples 1-2 are shown in Table 3.

[0026] Table 2 Process parameters of each embodiment

[0027]

[0028] Table 3 Process parameters of each comparative example

[0029]

[0030] The mechanical properties of the embodiments and comparative examples are shown in Table 4. The carbon dioxide corrosion performance meets the requirements of the standard NACE RP0775-2005, and the corrosion rate is less than 0.125 mm / a.

[0031] Table 4 Mechanical properties

[0032]

[0033] It can be seen from Table 2 and Table 3 that compared with the comparative example, the embodiment has less alloy content, a shorter production process, a significantly reduced production cost, and has good strength, low-temperature toughness and carbon dioxide corrosion resistance, fully meeting the requirements for steel for supercritical carbon dioxide transmission pipelines.

[0034] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for producing a hot-rolled steel coil for a supercritical carbon dioxide delivery pipeline, characterized in that: The smelting adopts LF+RH double refining, and the gas and inclusion content are strictly controlled; the inclusions of A, B, C, D, and DS are not greater than level 1.5, and the total inclusions are less than level 4.0; the continuous casting adopts dynamic soft pressure reduction and electromagnetic stirring, and the quality of the ingot reaches level 1.0 of class C; the slab is placed for at least 48 hours after continuous casting before heating and rolling, the heating temperature of the slab is 1160-1200℃, the heating time is 200-300min, and the heating time should not be too long. long to prevent surface oxidation; the rolling adopts two-stage rolling of rough rolling and finishing rolling, the rough rolling adopts two stands, the start rolling temperature is ≥1100℃, the rough rolling pass adopts a large reduction rate, and the cumulative reduction rate is 78%-83%; the finishing rolling adopts seven-stand continuous rolling, the start rolling temperature is ≤980℃, the cumulative reduction rate of finishing rolling is 70%-75%, and the final rolling temperature is 820-860℃; after rolling, the steel coil is cooled by dense laminar flow cooling, cooled to 600-640℃ and coiled to obtain the steel coil; The chemical composition of the hot-rolled steel coil for supercritical carbon dioxide delivery pipeline is C: 0.03-0.05%, Si: 0.10-0.30%, Mn: 1.20-1.40%, P: ≤0.010%, S: ≤0.002%, Nb: 0.030-0.050%, Ti: 0.005-0.020%, Cr: 0.20-0.40%, Ni: 0.10-0.25%, Al: 0.020-0.050%, and the balance is Fe and unavoidable impurities.

2. The method for producing a hot-rolled steel coil for supercritical carbon dioxide delivery pipeline according to claim 1, characterized in that: The microstructure is fine ferrite and a small amount of pearlite. The product has excellent comprehensive performance and the impact energy at -60℃ is greater than 300J.

3. The method for producing a hot-rolled steel coil for supercritical carbon dioxide delivery pipeline according to claim 1, characterized in that: The carbon dioxide environment corrosion test was carried out using an autoclave, and the product has good resistance to carbon dioxide corrosion.

4. The method for producing a hot-rolled steel coil for supercritical carbon dioxide delivery pipeline according to claim 1, characterized in that: The chemical composition of the hot-rolled steel coil for the supercritical carbon dioxide delivery pipeline is C: 0.04%, Si: 0.20%, Mn: 1.30%, P: 0.007%, S: 0.0015%, Nb: 0.040%, Ti: 0.015%, Cr: 0.30%, Ni: 0.15%, Al: 0.035%, and the balance is Fe and unavoidable impurities.

5. The method for producing a hot-rolled steel coil for supercritical carbon dioxide delivery pipeline according to claim 1, characterized in that: The chemical composition of the hot-rolled steel coil for the supercritical carbon dioxide delivery pipeline is C: 0.05%, Si: 0.15%, Mn: 1.25%, P: 0.006%, S: 0.0012%, Nb: 0.045%, Ti: 0.010%, Cr: 0.35%, Ni: 0.25%, Al: 0.035%, and the balance is Fe and unavoidable impurities.

6. The method for producing a hot-rolled steel coil for supercritical carbon dioxide delivery pipeline according to claim 1, characterized in that: The chemical composition of the hot-rolled steel coil for the supercritical carbon dioxide delivery pipeline is C: 0.05%, Si: 0.25%, Mn: 1.40%, P: 0.008%, S: 0.0020%, Nb: 0.035%, Ti: 0.018%, Cr: 0.25%, Ni: 0.20%, Al: 0.040%, and the balance is Fe and unavoidable impurities.

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