11mnnimodr medium and heavy plate for high-strength ultra-low temperature vessel and production method therefor

Abstract

A 11MnNiMoDR medium and heavy plate for a high-strength ultra-low temperature container and a production method therefor, belonging to the technical field of steel production. The medium and heavy plate comprises the following chemical components in percentages by mass: 0.03%-0.11% of C, 1.4%-1.9% of Mn, ≤0.008% of P, ≤0.003% of S, 0.1%-0.40% of Si, 0.3% -0.9% of Ni, 0.1%-0.30% of Mo, ≤0.05% of Nb, ≤0.05% of V, ≥0.02% of Al, ≤2 ppm of [H], ≤120 ppm of [N], ≤30 ppm of [0], and the balance of Fe and inevitable impurities, the sum of the described components being 100%. By means of reasonable component design, combined with suitable smelting, rolling, and post-rolling rapid cooling and quenching-tempering heat treatment processes, the manufactured medium and heavy plates have higher toughness and strength and cover the full thickness specifications required for the construction of storage and transportation facilities.

Description

11MnNiMoDR medium plate for high-strength ultra-low temperature container and production method thereof TECHNICAL FIELD

[0001] The present application relates to a medium plate and a production method thereof, in particular to a 11MnNiMoDR medium plate for high-strength ultra-low temperature container and a production method thereof, and belongs to the technical field of steel production. BACKGROUND

[0002] With the increasing demand for low-temperature petrochemical raw and auxiliary materials such as propylene, propane, ethane and acetylene, the demand for ultra-low temperature steel for the construction of low-temperature spherical tanks or storage tanks and other storage and transportation equipment has also increased. In order to ensure the safety of the steel plate, a steel plate with a lower temperature than the medium temperature of-88℃ liquid ethane is required; in order to reduce the self-weight and material cost of the equipment, the steel plate needs to have higher strength; in order to more accurately design and manufacture the position of the storage and transportation facilities, a thinner gauge steel plate is also required, such as a 5mm gauge steel plate used for low-temperature containers. However, thin gauge steel plates are difficult to produce successfully due to rapid cooling during rolling, which can cause defects such as waves, buckling and rolling waste.

[0003] The application No. 202010235608.8 introduces a production method of ultra-low temperature high-strength 13MnNi6-3 container steel. The method uses a cast blank production and cooperates with a reasonable controlled rolling and controlled cooling, normalizing + tempering process. The produced 13MnNi6-3 container steel has a specification of 30-60mm, a yield strength of ≥375MPa, a tensile strength of ≥510MPa, and a low-temperature impact detection temperature of-90℃. The application No. 202010235602.0 introduces a production method of ultra-low temperature high-core impact large-thickness 13MnNi6-3 container steel. The method uses a cast blank production and cooperates with a reasonable controlled rolling process, quenching + tempering process to produce 80mm thick-80℃ ultra 13MnNi6-3 container steel, which has a tensile strength of ≥498MPa at 1 / 4 thickness and 1 / 2 thickness. The application No. 202211513903.0 introduces a 11MnNiDR steel plate for high-strength high-toughness pressure container and a manufacturing method thereof. The method uses low-carbon equivalent design and adds Ni, Nb and Ti alloys, controlled rolling and controlled cooling, quenching + tempering to produce 11MnNiDR steel with a yield strength of ≥400MPa, a tensile strength of ≥560MPa, a low-temperature impact detection temperature of-70℃, and a microstructure type of low-carbon bainite + ferrite. The reported maximum thickness is 100mm.

[0004] The above patents are all through the design of components, match the appropriate process production low temperature steel products, but the product strength is low and impact temperature can not meet the more low than liquid low temperature medium such as ethane, and the thinnest specification reported does not reach 5mm steel plate with high production difficulty, how to redesign the composition and production process, effectively improve the toughness and strength of the steel plate and cover the full thickness specification required for the construction of storage and transportation facilities is the technical problem to be solved at present.

[0005] SUMMARY

[0006] The present application is directed to the above technical problems, overcome the defects of the prior art, provide a kind of 11MnNiMoDR medium plate for high strength ultra-low temperature container and its production method, this method is through reasonable component design, match appropriate smelting, rolling and post-rolling rapid cooling and quenching and tempering heat treatment process, produce medium plate toughness and strength higher and cover the full thickness specification required for the construction of storage and transportation facilities.

[0007] In order to solve the above technical problems, the present application provides a kind of 11MnNiMoDR medium plate for high strength ultra-low temperature container, the chemical composition of the medium plate is as follows according to mass percentage: C:0.03%~0.11%, Mn:1.4%~1.9%, P≤0.008%, S≤0.003%, Si:0.1%~0.40%, Ni:0.3%~0.9%, Mo:0.1%~0.30%, Nb≤0.05%, V≤0.05%, Al≥0.02%, [H]≤2ppm, [N]≤120ppm, [0]≤30ppm, the balance is Fe and inevitable impurities, the sum of the above components is 100%.

[0008] The further limited technical scheme of the present application is:

[0009] Further, in the aforementioned 11MnNiMoDR medium plate for high strength ultra-low temperature container, the chemical composition of the medium plate is as follows according to mass percentage: C:0.03%~0.10%, Mn:1.4%~1.8%, P≤0.005%, S≤0.002%, Si:0.1%~0.40%, Ni:0.3%~0.7%, Mo:0.15%~0.25%, Nb:0.02%~0.04%, V:0.020%~0.040%, Al:0.02%~0.07%, [H]≤2ppm, [N]≤60ppm, [0]≤20ppm, the balance is Fe and inevitable impurities, the sum of the above components is 100%.

[0010] The present application also designs a production method of 11MnNiMoDR medium plate for high strength ultra-low temperature container, specifically comprising the following steps:

[0011] (1) KR pre-desulfurization treatment: after the first slagging, the temperature is controlled at 1350-1370 DEG C, and the purified magnesium desulfurizer is sprayed for 25 minutes, the desulfurization is carried out by stirring, the S in the molten iron after desulfurization is less than or equal to 0.006%, the temperature drop after desulfurization is less than or equal to 50 DEG C, and after the end, the second slagging is carried out;

[0012] (2) Molten steel smelting: scrap steel, molten iron and slag are added in the oxygen top and bottom combined blowing converter, the gun position is controlled according to the molten iron temperature during the blowing process, the final slag basicity is controlled to be 4.0, and the P content at the end point is less than or equal to 0.005%;

[0013] Argon blowing is carried out in the whole refining process of the LF furnace, the temperature is raised and the slag is formed within 10-15 minutes at the beginning of refining, the calcium wire feeding amount is controlled according to the S content in the molten steel, the calcium-aluminum ratio and the Ca content of the top slag of the refining slag, the soft blowing is carried out for 5-10 minutes at the end of wire feeding, the molten steel temperature is controlled to be 1640-1680 DEG C at the end of refining, and the S at the end point is less than or equal to 0.001%;

[0014] The molten steel enters the RH vacuum treatment, the treatment is carried out for 25-40 minutes, the molten steel temperature is 1560-1590 DEG C at the end of the RH vacuum smelting, and the H at the end point is less than or equal to 2ppm;

[0015] (3) Continuous casting pouring: entering the continuous casting pouring station, argon blowing protection pouring is adopted in the whole continuous casting process, the pouring temperature is 1521-1546 DEG C, the superheat degree of the tundish is 20-45 DEG C, the blank pulling rate is 0.70-1.15 m / min, and the molten steel surface is kept from being red during the tundish pouring process;

[0016] The plate blank thickness is 150 mm and 460 mm;

[0017] (4) Rolling: the total furnace time of the plate blank is greater than or equal to 8 min / cm, the temperature is 1140-1250 DEG C, and the plate blank is rolled out of the furnace;

[0018] The steel plate with a thickness less than 10 mm is normally rolled and continuously rolled to the set thickness;

[0019] The steel plate with a thickness greater than or equal to 10 mm is two-stage controlled rolling: the first stage is continuously and uninterruptedly rolled by adopting a large rolling pass reduction rate, so that the dynamic and static recrystallization of the deformed metal is ensured;

[0020] The second stage is non-recrystallization controlled rolling, and the rolling pass reduction rate is greater than or equal to 10%;

[0021] The red temperature after rolling is controlled cooling is 720-740 DEG C;

[0022] (5) Heat treatment: the steel plate is subjected to quenching + tempering treatment after cooling and shot blasting treatment, is quenched and then water-cooled to room temperature, is tempered and then air-cooled to room temperature.

[0023] The further limited technical scheme of the present application is:

[0024] Further, in the production method of the 11MnNiMoDR medium plate for high-strength ultra-low temperature container, the LF furnace top slag basicity is controlled at 5-7 and the slag amount is controlled at 12-16 kg / ton of steel in step (2).

[0025] In the production method of the 11MnNiMoDR medium plate for high-strength ultra-low temperature container, the thickness <10 mm steel plate rolling control slab discharging temperature is ≥1200℃, the finish rolling temperature is ≥830℃ and the rolling pass is ≥11 in step (4).

[0026] In the production method of the 11MnNiMoDR medium plate for high-strength ultra-low temperature container, the thickness ≥10 mm steel plate two-stage controlled rolling, the total rolling pass in the recrystallization zone is 4, the cumulative reduction in the recrystallization zone is ≥40%, the finish rolling temperature is 820-860℃, the red temperature after rolling is 730-760℃, the cooling speed is controlled at 20-30℃ / s and the microstructure of the rolled steel plate is refined in step (4).

[0027] In the production method of the 11MnNiMoDR medium plate for high-strength ultra-low temperature container, the quenching temperature is 870-910℃, the total in-furnace time is 2.0±1 min / mm×steel plate thickness / mm and the water cooling is to room temperature in step (5); the tempering temperature is 590-620℃, the total heating time is 3.25±1 min / mm×steel plate thickness / mm and the air cooling is to room temperature.

[0028] In the production method of the 11MnNiMoDR medium plate for high-strength ultra-low temperature container, the produced steel plate thickness is 5-80 mm.

[0029] In the production method of the 11MnNiMoDR medium plate for high-strength ultra-low temperature container, the produced steel plate organization is tempered sorbite+ferrite, the grain size is 8.0, the yield strength is ≥440 MPa, the tensile strength is ≥570 MPa, the elongation after fracture is ≥20% and the average value of the impact energy at -100℃ is ≥120 J.

[0030] The beneficial effects of the present application are:

[0031] (1) phosphorus and sulfur increase the brittleness of steel, phosphorus reduces the plasticity of steel, phosphorus causes unstable welding performance, sulfur reduces the ductility and toughness of steel, causes cracks during rolling, the content of phosphorus and sulfur needs to be strictly controlled; carbon plays a key role in the strength of steel, but reduces its plasticity and toughness, in order to ensure the toughness of ultra-low temperature, a lower content needs to be controlled; nickel can reduce the ductile-brittle transition temperature of steel, improve the toughness, and at the same time can improve the strength, but the price is high, a suitable amount needs to be added; molybdenum can improve the hardenability and thermal strength, improve the tempering stability; manganese can improve the hardenability, significantly improve the strength, but when the content is too high, the plasticity and low temperature toughness of the steel decreases, a suitable amount needs to be added; Nb and V can refine the grain, reduce the temper brittleness, improve the welding performance, V can significantly improve the strength of the steel; through pre-desulfurization treatment and molten steel smelting, S≤0.002% is controlled; through deep desulfurization in the converter, P≤0.005% is controlled; the present application designs lower C, Si, P, S, strictly controls harmful elements P, S, controls C: 0.03%~0.11%, Si: 0.1%~0.40%, adds suitable Ni, Mo and Mn alloy elements, controls the content of Ni: 0.3%~0.9%, Mo: 0.1%~0.30%, Mn: 1.4%~1.9%, adds appropriate content of Nb≤0.05%, V≤0.05% trace elements, cooperates with suitable smelting, rolling and rapid cooling after rolling, refines the grain size of the steel plate; through a suitable quenching and tempering heat treatment process, a 5-80mm steel plate with a microstructure of tempered sorbite + ferrite, a grain size of 8.0 level, a yield strength≥440MPa, a tensile strength≥570MPa, an elongation after fracture≥20%, and an average value of impact energy at-100℃≥120J is produced, successfully solving the technical difficulty of matching high strength under the demand of high toughness at ultra-low temperature of the steel plate, and meeting the demand of low temperature petrochemical raw material storage and transportation container construction.

[0032] (2) The present application successfully solves the technical difficulty of producing high-strength, high-impact toughness at-100℃ ultra-low temperature 5mm thick 11MnNiMoDR container steel on a 3500mm rolling mill production line. BRIEF DESCRIPTION OF DRAWINGS

[0033] Fig. 1 is a metallographic structure photo of the 11MnNiMoDR medium plate for high-strength ultra-low temperature container in Example 1;

[0034] Fig. 2 is a metallographic structure photo of the 11MnNiMoDR medium plate for high-strength ultra-low temperature container in Example 2;

[0035] Fig. 3 is a metallographic structure photo of the 11MnNiMoDR medium plate for high-strength ultra-low temperature container in Example 3;

[0036] Fig. 4 is a grain size photo of the 11MnNiMoDR medium plate for high-strength ultra-low temperature container in Example 2. DETAILED DESCRIPTION

[0037] In order to make the present application clearer, further description will be made to a thick-wall alloy steel and a production method thereof according to the present application with reference to the accompanying drawings. The specific examples described herein are only used to explain the present application and not used to limit the present application.

[0038] Example 1

[0039] The present example provides a 11MnNiMoDR medium plate with a thickness of 5mm for high-strength ultra-low-temperature containers, and the chemical composition (unit, wt%) of the medium plate is as follows: C: 0.038%, Mn: 1.63%, P: 0.005%, S: 0.001%, Si: 0.14%, Ni: 0.38%, Mo: 0.18%, Nb: 0.03%, V: 0.028%, Al: 0.028%, [H]: 1ppm, [N]: 30ppm, [O]: 18ppm, and the balance being Fe and unavoidable impurities, and the sum of the above components being 100%.

[0040] The production method of the above-mentioned 11MnNiMoDR medium plate for high-strength ultra-low-temperature containers specifically includes the following steps:

[0041] (1) KR pre-desulfurization treatment: after the first slagging, the temperature is controlled at 1370℃, and the purified magnesium desulfurizer is sprayed for 25min, and the desulfurization is carried out by stirring, and the S content in the molten iron after desulfurization is 0.006%, and the temperature drop of desulfurization is 43℃, and after the end, the second slagging is carried out;

[0042] (2) Molten steel smelting: smelting by adding scrap steel, molten iron and slag in a 150-ton oxygen top and bottom combined blowing converter, and controlling the gun position according to the molten iron temperature during blowing, and controlling the final slag basicity to be 4.0, and the P content at the end point is 0.005%;

[0043] LF furnace refining, argon blowing throughout the process, temperature rising and slagging are completed within 15 minutes at the beginning of refining, the top slag basicity is controlled to be 5, the slag amount is controlled to be 14kg / ton of steel, the calcium wire feeding amount is controlled to be 140m / furnace according to the S content in the molten steel, the calcium-aluminum ratio and the Ca content of the top slag of the refining slag, the soft blowing is carried out for 10min after the wire feeding is completed, the molten steel temperature is controlled to be 1660℃ at the end of refining, and the end point S is 0.0008%;

[0044] The molten steel enters the RH vacuum treatment, and the treatment is carried out for 35min, and the molten steel temperature is 1580℃ at the end of the RH vacuum smelting, and the end point H is 1ppm;

[0045] (3) Continuous casting pouring: entering the continuous casting pouring station, argon blowing protection is used for continuous casting throughout the process, the pouring temperature is 1538℃, the superheat degree of the tundish is 37℃, the withdrawal rate is 1.15m / min, and the steel liquid surface is kept from being red during the tundish pouring process;

[0046] The argon blowing amount of the stopper is controlled during the steel pouring process, the liquid surface fluctuation of the crystallizer is slight, and the slab thickness is 150 mm;

[0047] (4) Rolling: the total slab time in the furnace is 155 min, the temperature is 1245℃, and the slab is rolled out of the furnace;

[0048] The final rolling temperature is 835℃, the rolling pass is 15, and the slab is continuously rolled to 5.5 mm;

[0049] (5) Heat treatment: the steel plate is cooled and shot blasted, then quenched + tempered, the temperature is 908℃, the holding time in the furnace is 15 min, quenched, water cooled to room temperature, and then taken out of the furnace; the tempering temperature is 610℃, the holding time in the furnace is 20 min, taken out of the furnace, and then air cooled to room temperature.

[0050] The 11MnNiMoDR medium plate for high-strength ultra-low-temperature containers produced in this embodiment has a microstructure of tempered sorbite plus ferrite, as shown in Figure 1, and the grain size is 8.0, the yield strength is 609 MPa, the tensile strength is 662 MPa, the elongation after fracture is 27%, and the average impact energy at -100℃ is 201 J.

[0051] Example 2

[0052] This embodiment provides a 11MnNiMoDR medium plate for high-strength ultra-low-temperature containers with a thickness of 36 mm, and the chemical composition (unit, wt%) is as follows: C: 0.038%, Mn: 1.63%, P: 0.005%, S: 0.001%, Si: 0.14%, Ni: 0.38%, Mo: 0.18%, Nb: 0.03%, V: 0.028%, Al: 0.028%, [H]: 1 ppm, [N]: 30 ppm, [O]: 18 ppm, and the balance is Fe and unavoidable impurities, and the sum of the above components is 100%.

[0053] The production method of the above-mentioned 11MnNiMoDR medium plate for high-strength ultra-low-temperature containers specifically includes the following steps:

[0054] (1) KR pre-desulfurization treatment: after the first slagging, the temperature is controlled at 1370℃, and the pure magnesium desulfurizer is sprayed and blown for 25 min, the desulfurization is carried out by stirring, the S content in the molten iron after desulfurization is 0.006%, the temperature drop during desulfurization is 43℃, and the second slagging is carried out after the end;

[0055] (2) Molten steel smelting: scrap steel, molten iron and slag are added in a 150-ton oxygen top and bottom combined blowing converter, the gun position is controlled according to the temperature of the molten iron during blowing, the final slag basicity is controlled at 4.0, and the P content at the end point is 0.005%;

[0056] LF furnace refining whole argon blowing, refining within 15 minutes to complete the temperature rise to form slag, top slag alkalinity control in 5, slag quantity control in 14 kg / t steel, according to the content of S in molten steel, refining slag top slag calcium aluminum ratio and Ca content control calcium line feeding amount is 140 m / furnace, blowing 10 min after the end of wire feeding, the refining end control molten steel temperature is 1660℃, the terminal S is 0.0008%;

[0057] The molten steel enters the RH vacuum treatment, and the treatment time is 35 min. The molten steel temperature at the end of the RH vacuum treatment is 1580℃, and the terminal H is 1 ppm.

[0058] (3) Continuous casting pouring: entering the continuous casting pouring station, the whole process of continuous casting adopts argon protection pouring, the pouring temperature is 1538℃, the tundish superheat is 37℃, and the blank drawing rate is 1.15 m / min. The liquid surface of the tundish is kept from being red during the pouring process.

[0059] The argon blowing amount of the stopper is controlled during the pouring process, the crystallizer liquid level fluctuation is slight, and the slab thickness is 150 mm.

[0060] (4) Rolling: the total slab in-furnace time is 150 min, and the temperature is 1150℃. The slab is discharged and rolled.

[0061] The first stage recrystallization zone accumulative reduction rate is 50%, the second stage adopts non-recrystallization controlled rolling, the rolling pass reduction rate is ≥10%, the finish rolling temperature is 830℃, the post-rolling red temperature is 740℃, and the rolling thickness is 36.8 mm.

[0062] (5) Heat treatment: after the steel plate is cooled and shot blasted, quenching + tempering treatment is carried out, the temperature is 880℃, the in-furnace time for quenching is 108 min, the water cooling is to room temperature, and the furnace is discharged. The tempering temperature is 600℃, the in-furnace time is 117 min, the furnace is discharged after the tempering, and the air cooling is to room temperature.

[0063] The 36 mm 11MnNiMoDR medium plate for high-strength ultra-low-temperature containers produced in this embodiment has a microstructure of tempered sorbite plus ferrite, as shown in Figs. 2 and 4. According to the existing technology test, the grain size is 8.0, the yield strength is 581 MPa, the tensile strength is 647 MPa, the elongation after fracture is 26%, and the average value of the impact energy at -100℃ is 212 J.

[0064] Example 3

[0065] The embodiment provides a 11MnNiMoDR medium plate for a high-strength ultralow-temperature container after 80 mm, and the chemical composition (unit, wt%) of the medium plate is as follows according to mass percentage: C: 0.07%, Mn: 1.58%, P: 0.003%, S: 0.0009%, Si: 0.19%, Ni: 0.72%, Mo: 0.21%, Nb: 0.03%, V: 0.034%, Al: 0.031%, [H]: 1 ppm, [N]: 40 ppm, [O]: 15 ppm, and the balance of Fe and inevitable impurities, and the sum of the above components is 100%.

[0066] The production method of the 11MnNiMoDR medium plate for the high-strength ultralow-temperature container is characterized in that the method specifically comprises the following steps.

[0067] (1) KR pre-desulfurization treatment: after the first slagging, the temperature is controlled to be 1360 DEG C, the purified magnesium desulfurizer is sprayed for 25 min, the desulfurization is performed through stirring, the S content in the molten iron after desulfurization is 0.005%, the desulfurization temperature drop is 38 DEG C, and the second slagging is performed after the end;

[0068] (2) Molten steel smelting: scrap steel, molten iron and slag are added into a 150-ton oxygen top and bottom combined blowing converter, the gun position is well controlled according to the molten iron temperature during blowing, the final slag basicity is controlled to be 4.0, and the P content at the end point is 0.004%;

[0069] Argon blowing is performed throughout the LF furnace refining, the temperature is raised and the slag is formed within 10 min after the start of refining, the top slag basicity is controlled to be 6, the slag amount is controlled to be 15 kg / ton of steel, the calcium wire feeding amount is controlled to be 130 m / oven according to the S content in the molten steel, the top slag calcium-aluminum ratio and the Ca content, the soft blowing is performed for 5 min after the end of wire feeding, the molten steel temperature is controlled to be 1670 DEG C at the end of refining, and the end point S is 0.0007%;

[0070] The molten steel enters the RH vacuum treatment, the treatment is performed for 35 min, and the molten steel temperature is 1580 DEG C at the end of the RH vacuum smelting, and the end point H is 0.8 ppm;

[0071] (3) Continuous casting pouring: entering the continuous casting pouring station, argon blowing protection pouring is adopted throughout the continuous casting, the pouring temperature is 1542 DEG C, the tundish superheat is 41 DEG C, the strand speed is 0.8 m / min, and the molten steel surface is kept from being seen red during the tundish pouring process;

[0072] The argon blowing amount of the stopper is controlled during the steel pouring process, the mold liquid level fluctuation is slight, and the poured slab thickness is 460 mm;

[0073] (4) Rolling: the total in-furnace time of the slab is 300 min, the temperature is 1148 DEG C, and the slab is rolled out of the furnace;

[0074] The first stage recrystallization zone accumulative reduction is 45%, the second stage adopts non-recrystallization controlled rolling, the rolling pass reduction is greater than or equal to 10%, the finish rolling temperature is 851 DEG C, the red temperature after rolling is 738 DEG C, and the thickness after rolling is 80.9 mm;

[0075] (5) heat treatment: after the steel plate is cooled and shot blasted, quenching + tempering treatment is carried out, the temperature is 875 DEG C, the quenching time in the furnace is 152 min, water cooling is carried out to room temperature, and then the furnace is discharged; the tempering temperature is 595 DEG C, the time in the furnace is 181 min, the furnace is discharged, and then air cooling is carried out to room temperature.

[0076] The production method of the 80 mm high-strength ultra-low-temperature container plate 11MnNiMoDR produced in the embodiment is as follows: the microstructure is tempered sorbite plus ferrite, as shown in Figure 3; through the existing technology test, the grain size is 8.0, the yield strength is 479 MPa, the tensile strength is 595 MPa, the elongation after fracture is 25%, and the average value of the impact energy at -100 DEG C is 189 J.

[0077] The present application produces the steel plate meeting the requirements by strictly controlling harmful elements P and S, adopting low C, adding suitable Ni, Mo and Mn alloy elements, controlling the content of suitable Nb and V trace elements, and cooperating with suitable smelting, rolling, rapid cooling after rolling and quenching and tempering heat treatment processes.

[0078] In addition to the above embodiments, the present application can also have other implementation manners. Any technical solution formed by equivalent replacement or equivalent transformation falls within the protection scope of the present application.

Claims

1. A 11MnNiMoDR medium plate for high-strength ultra-low-temperature containers, characterized in that, The medium plate has the following chemical components by mass percentage: C: 0.03%~0.11%, Mn: 1.4%~1.9%, P≤0.008%, S≤0.003%, Si: 0.1%~0.40%, Ni: 0.3%~0.9%, Mo: 0.1%~0.30%, Nb≤0.05%, V≤0.05%, Al≥0.02%, [H]≤2ppm, [N]≤120ppm, [O]≤30ppm, the balance being Fe and inevitable impurities, and the sum of the above components being 100%.

2. The 11MnNiMoDR medium plate for high-strength ultra-low-temperature containers according to claim 1, characterized in that, The medium plate has the following chemical components by mass percentage: C: 0.03%~0.10%, Mn: 1.4%~1.8%, P≤0.005%, S≤0.002%, Si: 0.1%~0.40%, Ni: 0.3%~0.7%, Mo: 0.15%~0.25%, Nb: 0.02%~0.04%, V: 0.020%~0.040%, Al: 0.02%~0.07%, [H]≤2ppm, [N]≤60ppm, [O]≤20ppm, the balance being Fe and inevitable impurities, and the sum of the above components being 100%.

3. A method of producing a 11MnNiMoDR medium plate for high-strength ultra-low-temperature containers as claimed in claim 1 or 2, characterized in that, Specifically comprising the following steps: (1) KR pre-desulfurization treatment: after the first slagging, the temperature is controlled at 1350-1370℃, and the purified magnesium desulfurizer is sprayed for 25min, the desulfurization is carried out by stirring, the S content in the molten iron after desulfurization is ≤0.006%, the temperature drop during desulfurization is ≤50℃, and after the end, the second slagging is carried out; (2) Molten steel smelting: adding scrap steel, molten iron and slag in the oxygen top and bottom combined blowing converter, controlling the gun position according to the temperature of the molten iron during blowing process, the final slag basicity is controlled at 4.0, and the final P content is ≤0.005%; Argon blowing is carried out throughout the LF furnace refining, the temperature is raised and the slag is formed within 10-15 minutes at the beginning of refining, the calcium wire feeding amount is controlled according to the S content in the molten steel, the calcium-aluminum ratio and the Ca content of the top slag of the refining slag, the soft blowing is carried out for 5-10min after the wire feeding is completed, the molten steel temperature is controlled at 1640-1680℃ at the end of refining, and the final S content is ≤0.001%; The molten steel enters the RH vacuum treatment, the treatment is carried out for 25-40min, the molten steel temperature is 1560-1590℃ at the end of the RH vacuum smelting, and the final H content is ≤2ppm; (3) Continuous casting pouring: entering the continuous casting pouring station, argon blowing protection pouring is adopted throughout the continuous casting, the pouring temperature is 1521~1546℃, the superheat degree of the tundish is 20-45℃, the withdrawal speed is 0.70~1.15m / min, and the molten steel surface is kept from being red during the tundish pouring process; The poured slab thickness is 150mm and 460mm; (4) Rolling: the total slab in-furnace time is ≥8min / cm, the temperature is 1140~1250℃, and the rolling is carried out after discharging from the furnace; The steel plate with a thickness of <10mm is normally rolled and continuously rolled to the set thickness; The steel plate with a thickness of ≥10mm is two-stage controlled rolled: the first stage is continuously rolled without interruption by using a large rolling pass reduction rate to ensure that the deformed metal undergoes dynamic and static recrystallization; The second stage is non-recrystallization controlled rolling, and the rolling pass reduction rate is ≥10%; The red temperature after controlled cooling is 720-740℃; (5) heat treatment: quenching + tempering treatment is carried out after the steel plate is cooled and shot-blasted, the steel plate is water-cooled to room temperature after quenching, and the steel plate is air-cooled to room temperature after tempering.

4. The method for producing a 11MnNiMoDR medium plate for high-strength ultra-low-temperature containers according to claim 3, characterized in that: In the step (2), the basicity of the LF top slag is controlled to be 5-7, and the slag amount is controlled to be 12-16 kg / ton of steel.

5. The method for producing a 11MnNiMoDR medium plate for high-strength ultra-low-temperature containers according to claim 3, characterized in that: In the step (4), the discharging temperature of the slab is controlled to be ≥1200℃, the final rolling temperature is controlled to be ≥830℃, and the rolling pass is ≥11 for the steel plate with a thickness <10 mm.

6. The method for producing a 11MnNiMoDR medium plate for high-strength ultra-low-temperature containers according to claim 3, characterized in that: In the step (4), the steel plate with a thickness ≥10 mm is controlled to be two-stage controlled rolling, the total rolling pass in the recrystallization zone is 4, the cumulative reduction in the recrystallization zone is ≥40%, the final rolling temperature is 820-860℃, the red temperature after rolling is 730-760℃, the cooling speed is controlled to be 20-30℃ / s, and the microstructure of the rolled steel plate is refined.

7. The method for producing a 11MnNiMoDR medium plate for high-strength ultra-low-temperature containers according to claim 3, characterized in that: In the step (5), the quenching temperature is 870-910℃, the total in-furnace time is 2.0±1 min / mm×steel plate thickness / mm, and the steel plate is water-cooled to room temperature; the tempering temperature is 590-620℃, the total heating time is 3.25±1 min / mm×steel plate thickness / mm, and the steel plate is air-cooled to room temperature.

8. The method for producing a 11MnNiMoDR medium plate for high-strength ultra-low-temperature containers according to claim 3, characterized in that: The produced steel plate has a thickness of 5-80 mm.

9. The method for producing a 11MnNiMoDR medium plate for high-strength ultra-low-temperature containers according to claim 3, characterized in that: The produced steel plate has a microstructure of tempered sorbite + ferrite, a grain size of 8.0, a yield strength ≥440 MPa, a tensile strength ≥570 MPa, an elongation after fracture ≥20%, and an average impact energy at -100℃ ≥120 J.

Images