Sleeve and preparation method of sleeve

Abstract

The invention relates to the technical field of steel for a casing pipe and a pipeline for hydrogen storage and transportation and a preparation process of the steel, and provides a casing pipe and a preparation method of the casing pipe, and the casing pipe comprises the following components in percentage by mass: 0.08-0.12% of C, less than or equal to 0.3% of Si, 0.6-0.8% of Mn, less than or equal to 0.010% of P, less than or equal to 0.005% of S, 0.6-1.2% of Cr, 0.6-0.8% of Mo, 0.01-0.05% of Nb, 0.05-0.08% of V, 0.05-0.15% of Ti, 0.001-0.003% of Ca, 0.002-0.009% of Re and the balance of Fe. By adding Cr, Mo, Nb, V, Ti and other refined grain sizes and steel purified Ca, rare earth Re and other elements, the cleanliness of the pipe body is high, the structure grains are fine, and the grain size reaches the level 9 or above. The yield strength is 655-724 MPa, the tensile strength is larger than or equal to 700 MPa, the ductility is larger than or equal to 25%, the transverse impact energy at the temperature of 0 DEG C is larger than or equal to 190 J, and the longitudinal impact energy at the temperature of 0 DEG C is larger than or equal to 220 J. Under the environment that the total pressure is 5MPa and the mixed medium of 10% hydrogen and 90% methane, the pulling / pressing alternating load R is equal to-1, the cycle number is 1 * 10 < 5 >, the fatigue strength sigma-1 of the pipe is larger than or equal to 485MPa, and the requirement for long-term use of the pipe in an underground hydrogen storage warehouse is met.

Description

Technical Field

[0001] The present application relates to the technical field of steel for casing and pipeline for hydrogen storage and transportation and their preparation process, and in particular to a casing and a method for preparing the casing. Background Art

[0002] In the related technology, during the long-term use of hydrogen storage tanks, the pipes will absorb the stored high-pressure hydrogen and decompose into hydrogen atoms. The small size of hydrogen atoms makes it very easy to penetrate into defects and dislocations in the metal lattice, and eventually interact with the metal material microstructure to form hydrogen corrosion such as hydrogen blistering, hydrogen embrittlement and stress corrosion, resulting in the performance of the metal material being reduced. Although the design of hydrogen storage tanks refers to the design of oil and gas wells, gas storage tanks, etc. to select corresponding pipe products, this type of pipe product does not fully consider the working characteristics of hydrogen storage tanks and cannot meet the safety risk requirements during the long-term operation of hydrogen storage tanks, especially the risk of fatigue damage to pipes caused by the combined action of alternating loads and hydrogen media. Summary of the invention

[0003] In view of this, the present application provides a sleeve and a method for preparing the sleeve.

[0004] Specifically, the present application is implemented through the following technical solutions:

[0005] According to a first aspect of the present application, a sleeve is provided, wherein the components and mass percentages of the sleeve are C: 0.08% to 0.12%, Si: ≤0.3%, Mn: 0.6% to 0.8%, P: ≤0.010%, S: ≤0.005%, Cr: 0.6% to 1.2%, Mo: 0.6% to 0.8%, Nb: 0.01% to 0.05%, V: 0.05% to 0.08%, Ti: 0.05% to 0.15%, Ca: 0.001% to 0.003%, Re: 0.002% to 0.009%, and the balance is Fe.

[0006] In the technical solution of this application, by adding Cr, Mo, Nb, V and Ti to refine the grain size and purify the steel, Ca, rare earth Re and other elements, the pipe body has high cleanliness, fine grains, and the grain size reaches above level 9. The casing meets the mechanical performance requirements of 95ksi steel grade oil well pipes, with a yield strength of 655MPa~724MPa, a tensile strength of ≥700MPa, an elongation of ≥25%, a transverse impact energy of ≥190J at 0℃, and a longitudinal impact energy of ≥220J at 0℃. Under a total pressure of 5MPa, a mixed medium of 10% hydrogen and 90% methane, the casing product has a tension / compression alternating load R=-1, and a cycle of 1×10 5 , the fatigue strength of the pipe σ -1 ≥485MPa, meeting the requirements for long-term use of pipes in underground hydrogen storage depots.

[0007] According to the second aspect of the present application, a method for preparing a casing is provided, which is used to prepare the casing of the first aspect. The method for preparing the casing comprises: smelting steel to obtain a first molten steel, vacuum degassing and refining the first molten steel to obtain a second molten steel, and continuously casting the second molten steel into a round billet to obtain a round billet; performing a first heating treatment on the round billet, and perforating the round billet after the first heating treatment to obtain a rough pipe; performing a second heating treatment on the rough pipe, and hot rolling the rough pipe after the second heating treatment to obtain a tube billet; spray cooling the tube billet, tempering and straightening the tube billet after the spray cooling treatment, and processing and assembling the tube billet after the tempering and straightening treatment to obtain the casing. The casing product prepared by this preparation method is subjected to a total pressure of 5MPa, a mixed medium environment of 10% hydrogen and 90% methane, and a tension / compression alternating load R=-1, and a cycle of 1×10 5 , the fatigue strength of the pipe σ -1 ≥485MPa, meeting the requirements for long-term use of pipes in underground hydrogen storage depots.

[0008] The technical solution provided by this application brings at least the following beneficial effects:

[0009] By adding Cr, Mo, Nb, V and Ti to refine the grain size and purify the steel, Ca, rare earth Re and other elements, the pipe body has high cleanliness, fine grains, and a grain size of more than 9. The casing meets the mechanical performance requirements of 95ksi steel grade oil well pipes, with a yield strength of 655MPa~724MPa, a tensile strength of ≥700MPa, an elongation of ≥25%, a transverse impact energy of ≥190J at 0℃, and a longitudinal impact energy of ≥220J at 0℃. Under a total pressure of 5MPa, a mixed medium of 10% hydrogen and 90% methane, the casing product has a tension / compression alternating load R=-1, and a cycle of 1×10 5 , the fatigue strength of the pipe σ -1 ≥485MPa, which can meet the requirements for pipes used in long-term injection and production of underground hydrogen storage depots. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] 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.

[0011] 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 related technical descriptions are briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0012] Figure 1One of the schematic flow diagrams of a method for preparing a sleeve provided in an embodiment of the present application;

[0013] Figure 2 A second schematic flow chart of a method for preparing a sleeve provided in an embodiment of the present application;

[0014] Figure 3 A third flow chart of a method for preparing a sleeve provided in an embodiment of the present application;

[0015] Figure 4 A fourth flow chart of a method for preparing a sleeve provided in an embodiment of the present application;

[0016] Figure 5 A fifth flow chart of a method for preparing a sleeve provided in an embodiment of the present application;

[0017] Figure 6 A sixth flow chart of a method for preparing a sleeve provided in an embodiment of the present application;

[0018] Figure 7 A seventh flow chart of a method for preparing a sleeve provided in an embodiment of the present application;

[0019] Figure 8 FIG8 is a flow chart of a method for preparing a sleeve provided in an embodiment of the present application;

[0020] Fig. 9 A ninth flow chart of a method for preparing a sleeve provided in an embodiment of the present application;

[0021] Fig.10 A tenth flow chart of a method for preparing a sleeve provided in an embodiment of the present application;

[0022] Fig.11 The eleventh flow chart of a method for preparing a sleeve provided in an embodiment of the present application. DETAILED DESCRIPTION

[0023] 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.

[0024] An embodiment of the present application provides a sleeve, the components and mass percentages of the sleeve are C: 0.08%~0.12%, Si: ≤0.3%, Mn: 0.6%~0.8%, P: ≤0.010%, S: ≤0.005%, Cr: 0.6%~1.2%, Mo: 0.6%~0.8%, Nb: 0.01%~0.05%, V: 0.05%~0.08%, Ti: 0.05%~0.15%, Ca: 0.001%~0.003%, Re: 0.002%~0.009%, and the balance is Fe.

[0025] Among them, C: Carbon is the main solid solution strengthening element, which can form a strengthening phase with a variety of alloys and improve the strength of steel. In this application, the C content is controlled to precipitate enough dispersed nano-carbides to play a strengthening role without reducing the heat treatment operation of the production line, so the C content is limited to 0.08% to 0.12%.

[0026] Si: Silicon mainly plays a deoxidizing role. An appropriate amount of silicon can significantly improve the strength and toughness of medium and low carbon steels and increase the tempering temperature of steel. However, too high a content of silicon can significantly inhibit the precipitation of carburization. In order to achieve the purpose of the invention, its content is limited to Si≤0.3%.

[0027] Mn: Manganese can significantly improve the hardenability of steel, improve the strength of steel, and increase the supercooling degree of austenite during cooling. However, when the content is too high, it is easy to segregate at the grain boundary to form a banded structure, which reduces the hydrogen embrittlement resistance of the steel. In order to achieve the purpose of the invention, this application limits its content to 0.6% to 0.8%.

[0028] P and S: The lower the sulfur and phosphorus content, the more favorable it is to the hydrogen corrosion and fatigue performance of steel. Therefore, in this application, the content is limited to P≤0.010% and S≤0.005% to ensure the improvement of the high toughness and fatigue performance of the steel.

[0029] Cr: Chromium can improve hardenability, toughness and corrosion resistance of steel. To achieve the purpose of the invention, the chromium content is controlled between 0.6% and 1.2%.

[0030] Mo: Mo is a strong carbide-forming element. Carbides are strong traps for hydrogen, which can improve the hydrogen embrittlement resistance and corrosion resistance of steel. It can effectively inhibit dislocation annihilation at high temperatures, increase the dislocation density in the matrix, increase the carbide nucleation position, and improve the fine grain strengthening and precipitation strengthening effects of steel. Therefore, the content of Mo is controlled between 0.6% and 0.8% in this application.

[0031] Nb: Niobium can form C and N compounds, and form fine grain structure and refined carbides in austenite, thereby improving the hardenability and tempering stability of steel, and improving the toughness and hydrogen embrittlement resistance of steel; therefore, the present application controls its content to be 0.01% to 0.05%.

[0032] V: Vanadium is a strong carbide-forming element, which can form C and N compounds, and has the effect of refining grains, improving strength and toughness, and improving the tempering stability of steel. Therefore, the content of vanadium is controlled within 0.05% to 0.08% in this application.

[0033] Ti: Titanium is a strong carbide-forming element that can fix nitrogen and carbon to form compounds such as titanium carbide, which has the effect of refining grains, improving strength and toughness, and improving the tempering stability of steel. Therefore, the content of titanium is controlled within 0.05% to 0.15% in this application.

[0034] Ca: Calcium can refine grains, change the composition, quantity and form of non-metallic inclusions, and is very beneficial to improving the toughness, corrosion resistance and fatigue properties of steel. When the content is greater than or equal to 0.003%, the inclusions increase, the cleanliness of the steel is reduced, and fatigue cracks are likely to start at the inclusions, causing the fatigue properties of the steel to decrease. In order to achieve the purpose of the invention, the Ca content is designed to be in the range of 0.001% to 0.003%.

[0035] Re: Rare earth elements have strong desulfurization and deoxidation capabilities. They not only purify molten steel, but also strengthen it. They can control the morphology of inclusions and carbides, improve grain boundaries and inhibit local weakening, and inhibit white spots and brittleness caused by hydrogen. In order to achieve the purpose of the invention, its content is controlled in the range of 0.002% to 0.009%.

[0036] In the technical solution of this application, by adding Cr, Mo, Nb, V and Ti to refine the grain size and purify the steel, Ca, rare earth Re and other elements, the pipe body has high cleanliness, fine grains, and the grain size reaches above level 9. The casing meets the mechanical performance requirements of 95ksi steel grade oil well pipes, with a yield strength of 655MPa~724MPa, a tensile strength of ≥700MPa, an elongation of ≥25%, a transverse impact energy of ≥190J at 0℃, and a longitudinal impact energy of ≥220J at 0℃. Under a total pressure of 5MPa, a mixed medium of 10% hydrogen and 90% methane, the casing product has a tension-compression alternating load R=-1, and a cycle of 1×10 5 , the fatigue strength of the pipe σ -1 ≥485MPa, meeting the requirements for long-term use of pipes in underground hydrogen storage depots.

[0037] Specifically, the components and mass percentages of the sleeve may be C: 0.09%, Si: 0.2%, Mn: 0.7%, P: 0.005%, S: 0.004%, Cr: 0.9%, Mo: 0.7%, Nb: 0.03%, V: 0.07%, Ti: 0.12%, Ca: 0.002%, Re: 0.006%, and the balance is Fe.

[0038] Specifically, the chemical composition of the casing raw material is Cr: 0.6% to 1.2%, Nb: 0.01% to 0.05%, V: 0.05% to 0.08%, and Re: 0.002% to 0.009%.

[0039] Specifically, the chemical composition of the casing raw material is Mo: 0.6% to 0.8%, and Ti: 0.05% to 0.15%.

[0040] Furthermore, the yield strength of the casing is 655MPa-724MPa, the tensile strength is ≥700MPa, the elongation is ≥25%, the transverse impact energy at 0°C is ≥190J, and the longitudinal impact energy at 0°C is ≥220J.

[0041] Furthermore, the microstructure of the sleeve is a mixed structure of martensite and bainite. It can be understood that the microstructure of the sleeve is a mixed structure mainly composed of martensite and bainite; wherein the volume content of martensite and bainite is greater than 90%, the volume content of martensite is greater than 70%, and the volume content of bainite is greater than 20%.

[0042] The embodiment of the present application also provides a method for preparing a casing, which is used to prepare the casing in any of the above embodiments, specifically to prepare a high-toughness casing with improved fatigue resistance under the coupling of hydrogen and stress.

[0043] See also Figure 1 The present application also provides a method for preparing a sleeve, which may include the following steps:

[0044] S102, smelting the steel to obtain a first molten steel, performing vacuum degassing and refining treatment on the first molten steel to obtain a second molten steel, and performing round billet continuous casting treatment on the second molten steel to obtain a round billet;

[0045] S104, performing a first heating treatment on the round blank, and performing a perforation treatment on the round blank after the first heating treatment to obtain a rough tube;

[0046] S106, performing a second heating treatment on the rough pipe, and performing hot rolling treatment on the rough pipe after the second heating treatment to obtain a tube blank;

[0047] S108, spray cooling the tube blank, tempering and straightening the tube blank after the spray cooling, and processing and assembling the tube blank after the tempering and straightening to obtain the casing.

[0048] In this embodiment, a method for preparing a casing is provided, which is used for preparing the casing. Specifically, the present application obtains a first molten steel by adding high-quality steel or scrap steel into an electric furnace for smelting, and the smelted first molten steel is subjected to off-furnace refining and vacuum degassing treatment to obtain a second molten steel. After the chemical composition and temperature of the second molten steel meet the design requirements, the second molten steel is continuously cast into a steel pipe round billet, and the continuous round billet is cut into a required length after cooling, wherein a crystallizer and an end electromagnetic stirring are used during the continuous casting process, and a casting protection treatment is performed.

[0049] Furthermore, the cut continuous round tube billet is sent to the annular heating furnace for heating, i.e., the first heating treatment is performed, after which the heated round tube billet is perforated by a puncher to form a rough tube, and then the rough tube is prepared into a rough tube by a three-roll continuous rolling mill, wherein the rough tube is controlled to be cooled to less than or equal to 550°C at a cooling rate greater than 50°C / s by an online controlled cold water tank. The heating temperature range of the annular heating furnace is set at 1050°C to 1300°C, and the spraying rate of the rough tube controlled cooling is limited to 1000 m3 / h to 2000 m3 / h.

[0050] Furthermore, a medium frequency induction heating device is used to reheat the rough pipe after controlled cooling, that is, to perform a second heating treatment. After the second heating treatment, it is sent to a hot tension reducing unit for thermomechanical rolling, and the pipe is reduced to the required specifications, and a hot flying saw is used to cut the pipe to a fixed length. Among them, the medium frequency heating temperature of the rough pipe is set to 900℃~1000℃, and the heating time is 2 minutes to 5 minutes; the hot rolling temperature range of the hot tension reducing machine is set to 850℃~950℃, and the cross-sectional area ratio of the steel pipe before and after the hot tension reducing is ≥1.3.

[0051] Furthermore, the pipe billets after hot tension reduction and sizing are subjected to two-stage step-by-step external spraying using two online controlled cold water tanks. Specifically, the temperature of the pipe billets before entering the water tank is controlled to be greater than or equal to 850°C. The two online controlled cold water tanks are arranged front and back with a spacing of 12 meters. Multiple annular sprays are used inside the controlled cold water tanks, and a steel pipe insulation device is installed between the two controlled cold water tanks. The steel pipe running speed is 1.2 m / s to 1.5 m / s, and the temperature drop of the insulation device is less than or equal to 5°C. Use the front controlled cooling water tank to spray the outer wall of the tube billet to reduce the overall tube billet temperature to between 450℃ and 550℃. The water spraying rate is 500 cubic meters / hour to 800 cubic meters / hour, and the cooling rate should be greater than 50℃ / s. Use the rear controlled cooling water tank to cool the overall tube billet temperature to below 50℃. The water spraying rate is 300 cubic meters / hour to 600 cubic meters / hour, and the cooling rate should be greater than 30℃ / s. Finally, cool to room temperature on the cooling bed.

[0052] Furthermore, the tube blank is subjected to tempering and straightening treatment after controlled cooling, the tempering temperature range is controlled at 650°C to 700°C, and the tempering time is controlled at 60 minutes to 90 minutes; hot straightening is performed after tempering, wherein the inlet temperature of the straightening machine is greater than or equal to 500°C, and the straightening temperature is controlled between 350°C and 450°C.

[0053] Furthermore, the entire pipe body is subjected to non-destructive testing. After the non-destructive testing is qualified, the pipe ends are threaded, the couplings are screwed, the hydrostatic pressure test is performed, the protective rings are installed, the markings are sprayed and the paint is applied to make the finished casing.

[0054] In the present application, the casing prepared by this preparation method meets the mechanical property requirements of 95ksi steel grade oil well pipe, with a yield strength of 655MPa-724MPa, a tensile strength of ≥700MPa, an elongation of ≥25%, a transverse impact energy of ≥190J at 0°C, and a longitudinal impact energy of ≥220J at 0°C. The casing product is subjected to a total pressure of 5MPa, a mixed medium of 10% hydrogen and 90% methane, a tension / compression alternating load R=-1, and a cycle of 1×10 5 , the fatigue strength of the pipe σ -1 ≥485MPa, meeting the requirements for long-term use of pipes in underground hydrogen storage. The problem is that during the long-term service of the hydrogen storage, the alternating loads generated by hydrogen injection and production and the high-pressure hydrogen medium will accelerate the fatigue failure of the hydrogen storage pipes, that is, long-term service in the hydrogen medium will lead to reduced performance of the pipes, such as plasticity and toughness. Material fatigue damage will seriously threaten the durability and integrity of the hydrogen storage, resulting in serious safety risks and major economic losses or accidents.

[0055] In some embodiments, see Figure 2 The embodiment of the present application provides a method for preparing a casing, which may include the following steps: performing a round billet continuous casting process on the second molten steel, specifically including:

[0056] S202, smelting the steel to obtain a first molten steel, performing vacuum degassing and refining treatment on the first molten steel to obtain a second molten steel, injecting the second molten steel into a crystallizer to cool and solidify, and performing terminal electromagnetic stirring and casting protection treatment to obtain a round billet;

[0057] S204, performing a first heating treatment on the round blank, and performing a perforation treatment on the round blank after the first heating treatment to obtain a rough tube;

[0058] S206, performing a second heating treatment on the rough pipe, and performing a hot rolling treatment on the rough pipe after the second heating treatment to obtain a tube blank;

[0059] S208, spray cooling the tube blank, tempering and straightening the tube blank after the spray cooling, and processing and assembling the tube blank after the tempering and straightening to obtain the casing.

[0060] In this embodiment, the second molten steel is subjected to round billet continuous casting, that is, the second molten steel is injected into a crystallizer to be cooled and solidified, and subjected to terminal electromagnetic stirring and casting protection treatment, and after cooling, the continuous round billet is cut into required lengths.

[0061] In some embodiments, see Figure 3 The embodiment of the present application provides a method for preparing a sleeve, which may include the following steps: performing a first heating treatment on a round blank, specifically including:

[0062] S302, smelting the steel to obtain a first molten steel, performing vacuum degassing and refining treatment on the first molten steel to obtain a second molten steel, and performing round billet continuous casting treatment on the second molten steel to obtain a round billet;

[0063] S304, sending the round billet into an annular heating furnace, heating it at a first preset temperature, and performing a perforation treatment on the round billet after the first heating treatment to obtain a rough tube;

[0064] S306, performing a second heating treatment on the rough pipe, and performing hot rolling treatment on the rough pipe after the second heating treatment to obtain a tube blank;

[0065] S308, spray cooling the tube blank, tempering and straightening the tube blank after the spray cooling, and processing and assembling the tube blank after the tempering and straightening to obtain the casing.

[0066] In this embodiment, the round billet is subjected to a first heating treatment, that is, the round billet is fed into an annular heating furnace and heated at a first preset temperature. Specifically, the cut continuous round tube billet is fed into the annular heating furnace for heating, wherein the heating temperature range of the annular heating furnace is controlled to be between 1050°C and 1300°C.

[0067] In some embodiments, the first preset temperature is 1050°C to 1300°C.

[0068] Specifically, the first preset temperature may be 1050°C, the first preset temperature may be 1200°C, and the first preset temperature may be 1300°C.

[0069] In some embodiments, see Figure 4 The embodiment of the present application provides a method for preparing a sleeve, which may include the following steps, before the second heating treatment is performed on the capillary tube:

[0070] S402, smelting the steel to obtain a first molten steel, performing vacuum degassing and refining treatment on the first molten steel to obtain a second molten steel, and performing round billet continuous casting treatment on the second molten steel to obtain a round billet;

[0071] S404, performing a first heating treatment on the round blank, and performing a perforation treatment on the round blank after the first heating treatment to obtain a rough tube;

[0072] S406, performing continuous rolling treatment on the rough pipe, and cooling the rough pipe after continuous rolling treatment;

[0073] S408, performing a second heating treatment on the rough pipe, and performing a hot rolling treatment on the rough pipe after the second heating treatment to obtain a tube blank;

[0074] S410, spray cooling the tube blank, tempering and straightening the tube blank after the spray cooling, and processing and assembling the tube blank after the tempering and straightening to obtain the casing.

[0075] In this embodiment, the rough pipe is subjected to continuous rolling treatment, and the rough pipe after continuous rolling treatment is cooled, that is, the rough pipe is prepared into a rough pipe by a three-roll continuous rolling mill unit, and the rough pipe is controlled to be cooled to less than or equal to 550°C at a cooling rate greater than 50°C / s by an online controlled cold water tank, wherein the water spray rate for controlling cooling of the rough pipe is 1000 cubic meters / hour to 2000 cubic meters / hour.

[0076] In some embodiments, see Figure 5 The embodiment of the present application provides a method for preparing a casing, which may include the following steps: cooling the rough casing after continuous rolling, specifically including:

[0077] S502, smelting the steel to obtain a first molten steel, performing vacuum degassing and refining treatment on the first molten steel to obtain a second molten steel, and performing round billet continuous casting treatment on the second molten steel to obtain a round billet;

[0078] S504, performing a first heating treatment on the round blank, and performing a perforation treatment on the round blank after the first heating treatment to obtain a rough tube;

[0079] S506, placing the capillary tube in a water spray tank, spraying water to cool the capillary tube at a first preset water spray rate, and cooling the capillary tube to a second preset temperature at the first preset cooling speed;

[0080] S508, performing a second heating treatment on the rough pipe, and performing a hot rolling treatment on the rough pipe after the second heating treatment to obtain a tube blank;

[0081] S510, spray cooling the tube blank, tempering and straightening the tube blank after the spray cooling, and processing and assembling the tube blank after the tempering and straightening to obtain the casing.

[0082] In this embodiment, the blank tube is subjected to cooling treatment, that is, the blank tube after continuous rolling is placed in a water spraying tank, and the blank tube is sprayed with water for cooling at a first preset water spraying rate, and is cooled to a second preset temperature at a first preset cooling speed; wherein the first preset water spraying rate is 1000m 3 / h~2000m 3 / h, the first preset cooling rate is greater than 50℃ / s, and the second preset temperature is less than or equal to 550℃.

[0083] In some embodiments, see Figure 6 The embodiment of the present application provides a method for preparing a sleeve, which may include the following steps: performing a second heating treatment on the capillary tube, specifically including:

[0084] S602, smelting the steel to obtain a first molten steel, performing vacuum degassing and refining treatment on the first molten steel to obtain a second molten steel, and performing round billet continuous casting treatment on the second molten steel to obtain a round billet;

[0085] S604, performing a first heating treatment on the round blank, and performing a perforation treatment on the round blank after the first heating treatment to obtain a rough tube;

[0086] S606, placing the rough tube in a medium frequency induction heating device, heating it at a third preset temperature for a first time, and hot rolling the rough tube after the second heating treatment to obtain a tube blank;

[0087] S608, spray cooling the tube blank, tempering and straightening the tube blank after the spray cooling, and processing and assembling the tube blank after the tempering and straightening to obtain the casing.

[0088] In this embodiment, the capillary tube is subjected to a second heating treatment, that is, the capillary tube is placed in a medium frequency induction heating device and heated at a third preset temperature for a first time, wherein the third preset temperature is 900°C to 1000°C and the first time is 2 minutes to 5 minutes. It can also be understood that the medium frequency induction heating device is used to reheat the blank tube after controlled cooling, wherein the medium frequency heating temperature of the blank tube is 900°C to 1000°C and the heating time is 2 minutes to 5 minutes.

[0089] In some embodiments, the third preset temperature is 900° C. to 1000° C., and the first time duration is 2 min to 5 min.

[0090] Specifically, the third preset temperature may be 900° C., the third preset temperature may be 950° C., the third preset temperature may be 1000° C., the first time length may be 2 minutes, the first time length may be 3 minutes, and the first time length may be 5 minutes.

[0091] In some embodiments, see Figure 7The embodiment of the present application provides a method for preparing a casing, which may include the following steps: hot rolling the rough casing after the second heating treatment, specifically including:

[0092] S702, smelting the steel to obtain a first molten steel, performing vacuum degassing and refining treatment on the first molten steel to obtain a second molten steel, and performing round billet continuous casting treatment on the second molten steel to obtain a round billet;

[0093] S704, performing a first heating treatment on the round blank, and performing a perforation treatment on the round blank after the first heating treatment to obtain a rough tube;

[0094] S706, performing a second heating treatment on the rough pipe, placing the rough pipe after the second heating treatment in a hot stretch reducing mill, and performing hot rolling treatment at a fourth preset temperature to obtain a tube blank;

[0095] S708, spray cooling the tube blank, tempering and straightening the tube blank after the spray cooling treatment, and processing and assembling the tube blank after the tempering and straightening treatment to obtain the casing.

[0096] In this embodiment, the rough pipe after the second heating treatment is subjected to hot rolling treatment, that is, the rough pipe after the second heating treatment is placed in a hot tension reducing mill and subjected to hot rolling treatment at a fourth preset temperature, and the fourth preset temperature is 850° C. to 950° C. It can also be understood that the rough pipe after the second heating treatment is sent to the hot tension reducing mill for thermomechanical rolling, and the diameter is reduced to a tube blank of the required specification, and a hot flying saw is used for fixed-length cutting to form a fixed-length rolled pipe.

[0097] In some embodiments, the fourth preset temperature is 850° C. to 950° C., and the cross-sectional area ratio of the rough tube before hot rolling treatment to that after hot rolling treatment is greater than or equal to 1.3.

[0098] Specifically, the fourth preset temperature can be 850°C, the fourth preset temperature can be 900°C, the fourth preset temperature can be 950°C, and the cross-sectional area ratio of the rough pipe before and after hot rolling is greater than or equal to 1.3, that is, the cross-sectional area ratio of the steel pipe before and after hot stretch reduction is greater than or equal to 1.3.

[0099] In some embodiments, see Figure 8 The embodiment of the present application provides a method for preparing a casing, which may include the following steps: spray cooling the tube blank, specifically including:

[0100] S802, smelting the steel to obtain a first molten steel, performing vacuum degassing and refining treatment on the first molten steel to obtain a second molten steel, and performing round billet continuous casting treatment on the second molten steel to obtain a round billet;

[0101] S804, performing a first heating treatment on the round blank, and performing a perforation treatment on the round blank after the first heating treatment to obtain a rough tube;

[0102] S806, performing a second heating treatment on the rough pipe, and performing a hot rolling treatment on the rough pipe after the second heating treatment to obtain a tube blank;

[0103] S808, feeding the tube blank into the first circulation spraying device, spraying the tube blank with water at the second preset water spraying rate, and cooling it to the fifth preset temperature at the second preset cooling speed, feeding the tube blank cooled to the fifth preset temperature into the second circulation spraying device, spraying the tube blank with water at the third preset water spraying rate, and cooling it to the sixth preset temperature at the third preset cooling speed, tempering and straightening the tube blank after the spray cooling treatment, and processing and assembling the tube blank after the tempering and straightening treatment to obtain the casing.

[0104] In this embodiment, the tube blank is subjected to a spray cooling treatment, that is, the tube blank is sent into a first circulating spray device, and the tube blank is sprayed with water at a second preset water spray rate, and is cooled to a fifth preset temperature at the second preset cooling speed;

[0105] The tube blank cooled to the fifth preset temperature is sent to the second circulating spraying device, and the tube blank is sprayed with water at the third preset water spraying rate, and cooled to the sixth preset temperature at the third preset cooling speed. The second preset water spraying rate is 500m 3 / h~800m 3 / h, the second preset cooling speed is greater than 50℃ / s, the fifth preset temperature is 450℃~550℃, and the third preset water spraying rate is 300m 3 / h~600m 3 / h, the third preset cooling rate is greater than 30°C / s, and the sixth preset temperature is less than or equal to 50°C.

[0106] It can also be understood that the pipe billet after hot tension reduction and sizing is subjected to two-stage step-by-step external spraying using two online controlled cold water tanks. Specifically, the temperature of the pipe billet before entering the water tank is controlled to be greater than or equal to 850°C. The two online controlled cold water tanks are arranged front and back with a spacing of 12 meters. Multiple annular sprays are used inside the controlled cold water tank, and a steel pipe insulation device is installed between the two controlled cold water tanks. The running speed of the steel pipe is 1.2 m / s to 1.5 m / s, and the temperature drop of the insulation device is less than or equal to 5°C. Use the front controlled cooling water tank to spray the outer wall of the tube billet to reduce the overall tube billet temperature to between 450℃ and 550℃. The water spraying rate is 500 cubic meters / hour to 800 cubic meters / hour, and the cooling rate should be greater than 50℃ / s. Use the rear controlled cooling water tank to cool the overall tube billet temperature to below 50℃. The water spraying rate is 300 cubic meters / hour to 600 cubic meters / hour, and the cooling rate should be greater than 30℃ / s. Finally, cool to room temperature on the cooling bed.

[0107] In some embodiments, the second preset water spray rate is 500m 3 / h~800m 3 / h, the second preset cooling speed is greater than 50℃ / s, the fifth preset temperature is 450℃~550℃, and the third preset water spraying rate is 300m 3 / h~600m 3 / h, the third preset cooling rate is greater than 30°C / s, and the sixth preset temperature is less than or equal to 50°C.

[0108] Specifically, the second preset water spraying rate can be 500m 3 / h, the second preset water spray rate can be 600m 3 / h, the second preset water spray rate can be 800m 3 / h. The fifth preset temperature may be 450°C, the fifth preset temperature may be 500°C, the fifth preset temperature may be 550°C, and the third preset water spraying rate may be 300m 3 / h, the third preset water spray rate can be 400m 3 / h, the third preset water spray rate can be 600m 3 / h.

[0109] In some embodiments, see Fig. 9 The embodiment of the present application provides a method for preparing a casing, which may include the following steps: tempering the tube blank after the spray cooling treatment, specifically including:

[0110] S902, smelting the steel to obtain a first molten steel, performing vacuum degassing and refining treatment on the first molten steel to obtain a second molten steel, and performing round billet continuous casting treatment on the second molten steel to obtain a round billet;

[0111] S904, performing a first heating treatment on the round blank, and performing a perforation treatment on the round blank after the first heating treatment to obtain a rough tube;

[0112] S906, performing a second heating treatment on the rough pipe, and performing a hot rolling treatment on the rough pipe after the second heating treatment to obtain a tube blank;

[0113] S908, spray cooling the tube blank, controlling the tube blank after cooling to be tempered for a second time and straightened at a seventh preset temperature, and processing and assembling the tube blank after tempering and straightening to obtain a casing.

[0114] In this embodiment, the tube billet after spray cooling is tempered, that is, the tube billet after cooling is tempered at the seventh preset temperature for a second time, wherein the seventh preset temperature is 650°C to 700°C, and the second time is 60min to 90min. It can also be understood that the tube billet after cooling is tempered and straightened, the tempering temperature range is controlled at 650°C to 700°C, and the tempering time is controlled at 60min to 90min.

[0115] In some embodiments, the seventh preset temperature is 650° C. to 700° C., and the second time period is 60 min to 90 min.

[0116] Specifically, the seventh preset temperature may be 650° C., the seventh preset temperature may be 680° C., the seventh preset temperature may be 700° C., the second time length may be 60 min, the second time length may be 70 min, and the second time length may be 90 min.

[0117] In some embodiments, see Fig.10 The embodiment of the present application provides a method for preparing a casing, which may include the following steps: straightening the tube blank after the spray cooling treatment, specifically including:

[0118] S1002, smelting the steel to obtain a first molten steel, performing vacuum degassing and refining treatment on the first molten steel to obtain a second molten steel, and performing round billet continuous casting treatment on the second molten steel to obtain a round billet;

[0119] S1004, performing a first heating treatment on the round blank, and performing a perforation treatment on the round blank after the first heating treatment to obtain a rough tube;

[0120] S1006, performing a second heating treatment on the rough pipe, and performing a hot rolling treatment on the rough pipe after the second heating treatment to obtain a tube blank;

[0121] S1008, spray cooling the tube blank, tempering the tube blank after the spray cooling treatment, placing the tube blank in a medium straightening device, straightening it at an eighth preset temperature, and processing and assembling the tube blank after the tempering and straightening treatment to obtain a casing.

[0122] In this embodiment, the tube blank after spray cooling is straightened, that is, the tube blank is placed in a medium straightening device and straightened at an eighth preset temperature, wherein the eighth preset temperature is 350° C. to 450° C. It can also be understood that hot straightening is performed after tempering, the inlet temperature of the straightening machine is greater than or equal to 500° C., and the straightening temperature is controlled to be 350° C. to 450° C.

[0123] In some embodiments, the eighth preset temperature is 350°C to 450°C.

[0124] Specifically, the eighth preset temperature may be 350°C, the eighth preset temperature may be 400°C, and the eighth preset temperature may be 450°C.

[0125] In some embodiments, see Fig.11 The embodiment of the present application provides a method for preparing a casing, which may include the following steps: processing and assembling the tube blank after tempering and straightening treatment, specifically including:

[0126] S1102, smelting the steel to obtain a first molten steel, performing vacuum degassing and refining treatment on the first molten steel to obtain a second molten steel, and performing round billet continuous casting treatment on the second molten steel to obtain a round billet;

[0127] S1104, performing a first heating treatment on the round blank, and performing a perforation treatment on the round blank after the first heating treatment to obtain a rough tube;

[0128] S1106, performing a second heating treatment on the rough pipe, and performing a hot rolling treatment on the rough pipe after the second heating treatment to obtain a tube blank;

[0129] S1108, spray cooling the tube blank, tempering and straightening the tube blank after spray cooling, threading the end of the tube blank, screwing the coupling, installing the protective ring and spraying the paint to obtain the casing.

[0130] In this embodiment, the tube blank after tempering and straightening is processed and assembled, that is, the end of the tube blank is threaded, the coupling is screwed, the protective ring is installed and the paint is sprayed. It can also be understood that the whole tube body is subjected to non-destructive testing, and after the non-destructive testing is qualified, the tube end is threaded, the coupling is screwed, the hydrostatic test is performed, the protective ring is installed, the label is sprayed and the paint is applied, etc., to make the finished casing.

[0131] The casing prepared by this preparation method meets the mechanical property requirements of 95ksi steel grade oil well pipe, with a yield strength of 655MPa-724MPa, a tensile strength of ≥700MPa, an elongation of ≥25%, a transverse impact energy of ≥190J at 0℃, and a longitudinal impact energy of ≥220J at 0℃. The casing product is subjected to a total pressure of 5MPa, a mixed medium of 10% hydrogen and 90% methane, and a tension / compression alternating load R=-1, and a cycle of 1×10 5 , the fatigue strength of the pipe σ -1 ≥485MPa, meeting the requirements for long-term use of pipes in underground hydrogen storage depots.

[0132] In some embodiments, the steps of preparing the sleeve are as follows:

[0133] Step 1: Add high-quality scrap steel into an electric furnace for smelting, and subject the smelted molten steel to external refining and vacuum degassing. After its chemical composition and temperature meet the design requirements, the molten steel is continuously cast into steel pipe round billets. After cooling, the continuous round billets are cut into required lengths. During the continuous casting process, crystallizer and end electromagnetic stirring are used, and casting protection is performed.

[0134] Step 2: The cut continuous round tube billet is sent to the annular heating furnace for heating, and the heated round tube billet is perforated by a puncher to form a rough tube, and then the rough tube is prepared into a rough tube by a three-roll continuous rolling mill, and the rough tube is controlled to cool to ≤550℃ by an online controlled cold water tank at a cooling rate greater than 50℃ / s. The heating temperature range of the annular heating furnace is as follows: 1050℃~1300℃, and the spraying rate of the rough tube controlled cooling is 1000m3 / h~2000m3 / h.

[0135] Step 3: Use medium frequency induction heating device to reheat the rough pipe after controlled cooling, then send it to the hot tension reducing unit for thermomechanical rolling, and reduce the diameter to the required specification of the pipe billet, and use hot flying saw to cut to size to form a fixed-length rolled pipe. The medium frequency heating temperature of the rough pipe is 900℃~1000℃, and the heating time is 2 minutes to 5 minutes; the hot rolling temperature range of the hot tension reducing machine is 850℃~950℃, and the cross-sectional area ratio of the steel pipe before and after the hot tension reducing is ≥1.3.

[0136] Step 4: After the hot tension reduction and sizing, the tube billet is sprayed in two stages using two online controlled cold water tanks to control the temperature of the tube billet before entering the water tank to be ≥850℃. The two online controlled cold water tanks are arranged front and back with a spacing of 12 meters. Multiple annular sprays are used inside the controlled cold water tank, and a steel pipe insulation device is installed between the two controlled cold water tanks. The steel pipe running speed is 1.2m / s~1.5m / s, and the temperature drop of the insulation device is ≤5℃. The outer wall of the tube billet is sprayed with the front controlled cold water tank to reduce the overall tube billet temperature to between 450℃ and 550℃. The water spray rate is 500m3 / h~800m3 / h, and the cooling rate should be greater than 50℃ / s; the overall tube billet temperature is cooled to below 50℃ using the rear controlled cold water tank, and the water spray rate is 300m3 / h~600m3 / h, and the cooling rate should be greater than 30℃ / s; finally, it is cooled to room temperature on the cooling bed.

[0137] Step 5: After controlled cooling, the tube blank is tempered and straightened. The tempering temperature range is 650℃~700℃, and the tempering time is controlled at 60 minutes to 90 minutes. After tempering, hot straightening is performed. The inlet temperature of the straightening machine is ≥500℃, and the straightening temperature is controlled at 350℃~450℃.

[0138] Step 6: After the entire pipe body passes the non-destructive testing, the pipe ends are threaded, the couplings are screwed, the hydrostatic test is performed, the protective ring is installed, the marking is sprayed and the paint is applied to make the finished casing.

[0139] The casing prepared by this preparation method meets the mechanical property requirements of 95ksi steel grade oil well pipe, with a yield strength of 655MPa-724MPa, a tensile strength of ≥700MPa, an elongation of ≥25%, a transverse impact energy of ≥190J at 0℃, and a longitudinal impact energy of ≥220J at 0℃. The casing product is subjected to a total pressure of 5MPa, a mixed medium of 10% hydrogen and 90% methane, and a tension / compression alternating load R=-1, and a cycle of 1×10 5 , the fatigue strength of the pipe σ -1 ≥485MPa, meeting the requirements for long-term use of pipes in underground hydrogen storage depots.

[0140] Although this specification includes many specific implementation details, these should not be interpreted as limiting the scope of any invention or the scope of protection claimed, but are mainly used to describe the features of the specific embodiments of specific inventions. Certain features described in multiple embodiments in this specification may also be implemented in combination in a single embodiment. On the other hand, the various features described in a single embodiment may also be implemented separately in multiple embodiments or in any suitable sub-combination. In addition, although features may work in certain combinations as described above and even initially claim protection, one or more features from the claimed combination may be removed from the combination in some cases, and the claimed combination may point to a sub-combination or a variation of a sub-combination.

[0141] Similarly, although operations are depicted in a particular order in the accompanying drawings, this should not be understood as requiring that these operations be performed in the particular order shown or performed sequentially, or requiring that all illustrated operations be performed to achieve the desired results. In some cases, multitasking and parallel processing may be advantageous. In addition, the separation of various system modules and components in the above-described embodiments should not be understood as requiring such separation in all embodiments, and it should be understood that the described program components and systems can generally be integrated together in a single software product, or packaged into multiple software products.

[0142] Thus, specific embodiments of the subject matter have been described. Other embodiments are within the scope of the appended claims. In some cases, the actions recited in the claims can be performed in a different order and still achieve the desired results. In addition, the processes depicted in the drawings do not necessarily require the particular order or sequential order shown to achieve the desired results. In some implementations, multitasking and parallel processing may be advantageous.

[0143] It should be noted that, in this article, relational terms such as "first" and "second" are only used 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. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0144] 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 casing, characterized in that: The components and mass percentages of the sleeve are C: 0.08%-0.12%, Si: ≤0.3%, Mn: 0.6%-0.8%, P: ≤0.010%, S: ≤0.005%, Cr: 0.6%-1.2%, Mo: 0.6%-0.8%, Nb: 0.01%-0.05%, V: 0.05%-0.08%, Ti: 0.05%-0.15%, Ca: 0.001%-0.003%, Re: 0.002%-0.009%, and the balance is Fe.

2. The sleeve according to claim 1, characterized in that The sleeve has a yield strength of 655MPa to 724MPa, a tensile strength of ≥700MPa, an elongation of ≥25%, a transverse impact energy of ≥190J at 0°C, and a longitudinal impact energy of ≥220J at 0°C.

3. The sleeve according to claim 1, characterized in that The microstructure of the sleeve is a mixed structure of martensite and bainite; Among them, the volume content of martensite and bainite is greater than 90%, the volume content of martensite is greater than 70%, and the volume content of bainite is greater than 20%.

4. A method for preparing a sleeve, characterized in that: Used to prepare a sleeve according to any one of claims 1 to 3, the preparation method of the sleeve comprising: Smelting steel to obtain a first molten steel, performing vacuum degassing and refining treatment on the first molten steel to obtain a second molten steel, and performing round billet continuous casting on the second molten steel to obtain a round billet; Performing a first heating treatment on the round blank, and performing a perforation treatment on the round blank after the first heating treatment to obtain a rough tube; Performing a second heating treatment on the rough tube, and performing a hot rolling treatment on the rough tube after the second heating treatment to obtain a tube blank; The tube blank is subjected to spray cooling treatment, the tube blank subjected to spray cooling treatment is subjected to tempering and straightening treatment, and the tube blank subjected to tempering and straightening treatment is processed and assembled to obtain a casing.

5. The method for preparing the sleeve according to claim 4, characterized in that: The round billet continuous casting process of the second molten steel specifically comprises: The second molten steel is injected into a crystallizer to be cooled and solidified, and terminal electromagnetic stirring and pouring protection treatment are performed.

6. The method for preparing a sleeve according to claim 4, characterized in that: The first heating treatment of the round blank specifically includes: The round billet is fed into an annular heating furnace and heated at a first preset temperature.

7. The method for preparing a sleeve according to claim 6, characterized in that: The first preset temperature is 1050°C to 1300°C.

8. The method for preparing a sleeve according to claim 4, characterized in that: Before the capillary tube is subjected to the second heating treatment, the method further comprises: The rough pipe is subjected to continuous rolling treatment, and the rough pipe after the continuous rolling treatment is subjected to cooling treatment.

9. The method for preparing a sleeve according to claim 8, characterized in that: The step of cooling the rough pipe after continuous rolling specifically includes: The capillary tube is placed in a water spraying tank, and the capillary tube is sprayed with water for cooling at a first preset water spraying rate, and cooled to a second preset temperature at a first preset cooling speed; Among them, the first preset water spray rate is 1000m 3 / h~2000m 3 / h, the first preset cooling rate is greater than 50°C / s, and the second preset temperature is less than or equal to 550°C.

10. The method for preparing a sleeve according to claim 4, characterized in that: The second heating treatment of the capillary tube specifically includes: The capillary tube is placed in a medium frequency induction heating device and heated at a third preset temperature for a first time period.

11. The method for preparing a sleeve according to claim 10, characterized in that: The third preset temperature is 900° C. to 1000° C., and the first time duration is 2 min to 5 min.

12. The method for preparing a sleeve according to claim 4, characterized in that: The step of hot rolling the rough tube after the second heating treatment specifically includes: The rough pipe after the second heat treatment is placed in a hot stretch reducing mill and hot rolled at a fourth preset temperature.

13. The method for preparing a sleeve according to claim 12, characterized in that: The fourth preset temperature is 850° C. to 950° C., and the cross-sectional area ratio of the rough tube before hot rolling treatment to that after hot rolling treatment is greater than or equal to 1.

3.

14. The method for preparing a sleeve according to claim 4, characterized in that: The spray cooling treatment of the tube blank specifically includes: The tube blank is fed into a first circulating spraying device, and the tube blank is sprayed with water for cooling at a second preset water spraying rate, and is cooled to a fifth preset temperature at the second preset cooling speed; The tube blank cooled to the fifth preset temperature is sent to the second circulation spraying device, and the tube blank is sprayed with water at a third preset water spraying rate, and is cooled to a sixth preset temperature at the third preset cooling speed.

15. The method for preparing a sleeve according to claim 14, characterized in that: The second preset water spraying rate is 500m 3 / h~800m 3 / h, the second preset cooling speed is greater than 50°C / s, the fifth preset temperature is 450°C to 550°C, and the third preset water spraying rate is 300m 3 / h~600m 3 / h, the third preset cooling rate is greater than 30°C / s, and the sixth preset temperature is less than or equal to 50°C.

16. The method for preparing a sleeve according to claim 4, characterized in that: The step of subjecting the tube blank after the spray cooling treatment to tempering treatment specifically comprises: The tube blank after the cooling treatment is controlled to be tempered at a seventh preset temperature for a second period of time.

17. The method for preparing a sleeve according to claim 16, characterized in that: The seventh preset temperature is 650° C. to 700° C., and the second time period is 60 min to 90 min.

18. The method for preparing a sleeve according to claim 4, characterized in that: The straightening treatment of the tube blank after the spray cooling treatment specifically includes: The tube blank is placed in a medium straightening device and straightened at an eighth preset temperature.

19. The method for preparing a sleeve according to claim 18, characterized in that: The eighth preset temperature is 350°C to 450°C.

20. The method for preparing a sleeve according to claim 4, characterized in that: The processing and assembling of the tube blank after tempering and straightening treatment specifically includes: The end of the tube blank is threaded, a coupling is screwed on, a protective ring is installed and the tube is painted.

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