CN117230377A - Steel for new energy electric automobile battery pack support frame and production method thereof - Google Patents
Steel for new energy electric automobile battery pack support frame and production method thereof Download PDFInfo
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- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 185
- 239000010959 steel Substances 0.000 title claims abstract description 185
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 25
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 93
- 239000002893 slag Substances 0.000 claims abstract description 75
- 238000007670 refining Methods 0.000 claims abstract description 51
- 229910052742 iron Inorganic materials 0.000 claims abstract description 43
- 238000006477 desulfuration reaction Methods 0.000 claims abstract description 27
- 230000023556 desulfurization Effects 0.000 claims abstract description 27
- 229910052717 sulfur Inorganic materials 0.000 claims abstract description 25
- 239000011593 sulfur Substances 0.000 claims abstract description 20
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 claims abstract description 18
- 229910052751 metal Inorganic materials 0.000 claims abstract description 4
- 239000002184 metal Substances 0.000 claims abstract description 4
- OSMSIOKMMFKNIL-UHFFFAOYSA-N calcium;silicon Chemical compound [Ca]=[Si] OSMSIOKMMFKNIL-UHFFFAOYSA-N 0.000 claims abstract description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 claims description 88
- 238000003723 Smelting Methods 0.000 claims description 50
- 238000005096 rolling process Methods 0.000 claims description 46
- 229910052786 argon Inorganic materials 0.000 claims description 44
- 238000007664 blowing Methods 0.000 claims description 31
- 238000000034 method Methods 0.000 claims description 30
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- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 13
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- 229910010271 silicon carbide Inorganic materials 0.000 claims description 10
- 229910052721 tungsten Inorganic materials 0.000 claims description 10
- 238000007872 degassing Methods 0.000 claims description 9
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 8
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- 230000009467 reduction Effects 0.000 claims description 8
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 7
- CKUAXEQHGKSLHN-UHFFFAOYSA-N [C].[N] Chemical compound [C].[N] CKUAXEQHGKSLHN-UHFFFAOYSA-N 0.000 claims description 7
- 229910052799 carbon Inorganic materials 0.000 claims description 7
- 239000012535 impurity Substances 0.000 claims description 7
- 229910052698 phosphorus Inorganic materials 0.000 claims description 7
- 239000000843 powder Substances 0.000 claims description 7
- 229910052748 manganese Inorganic materials 0.000 claims description 6
- 229910018072 Al 2 O 3 Inorganic materials 0.000 claims description 5
- 239000005997 Calcium carbide Substances 0.000 claims description 5
- 229910000604 Ferrochrome Inorganic materials 0.000 claims description 5
- 229910000592 Ferroniobium Inorganic materials 0.000 claims description 5
- 229910000519 Ferrosilicon Inorganic materials 0.000 claims description 5
- WUKWITHWXAAZEY-UHFFFAOYSA-L calcium difluoride Chemical compound [F-].[F-].[Ca+2] WUKWITHWXAAZEY-UHFFFAOYSA-L 0.000 claims description 5
- 229910052804 chromium Inorganic materials 0.000 claims description 5
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- 238000002791 soaking Methods 0.000 claims description 5
- CLZWAWBPWVRRGI-UHFFFAOYSA-N tert-butyl 2-[2-[2-[2-[bis[2-[(2-methylpropan-2-yl)oxy]-2-oxoethyl]amino]-5-bromophenoxy]ethoxy]-4-methyl-n-[2-[(2-methylpropan-2-yl)oxy]-2-oxoethyl]anilino]acetate Chemical compound CC1=CC=C(N(CC(=O)OC(C)(C)C)CC(=O)OC(C)(C)C)C(OCCOC=2C(=CC=C(Br)C=2)N(CC(=O)OC(C)(C)C)CC(=O)OC(C)(C)C)=C1 CLZWAWBPWVRRGI-UHFFFAOYSA-N 0.000 claims description 5
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 claims description 4
- 239000011777 magnesium Substances 0.000 claims description 4
- 229910052749 magnesium Inorganic materials 0.000 claims description 4
- 239000002131 composite material Substances 0.000 claims description 3
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- 229910000628 Ferrovanadium Inorganic materials 0.000 claims description 2
- 239000007789 gas Substances 0.000 claims description 2
- ZFGFKQDDQUAJQP-UHFFFAOYSA-N iron niobium Chemical compound [Fe].[Fe].[Nb] ZFGFKQDDQUAJQP-UHFFFAOYSA-N 0.000 claims description 2
- PNXOJQQRXBVKEX-UHFFFAOYSA-N iron vanadium Chemical compound [V].[Fe] PNXOJQQRXBVKEX-UHFFFAOYSA-N 0.000 claims description 2
- WPBNNNQJVZRUHP-UHFFFAOYSA-L manganese(2+);methyl n-[[2-(methoxycarbonylcarbamothioylamino)phenyl]carbamothioyl]carbamate;n-[2-(sulfidocarbothioylamino)ethyl]carbamodithioate Chemical compound [Mn+2].[S-]C(=S)NCCNC([S-])=S.COC(=O)NC(=S)NC1=CC=CC=C1NC(=S)NC(=O)OC WPBNNNQJVZRUHP-UHFFFAOYSA-L 0.000 claims description 2
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- 229910045601 alloy Inorganic materials 0.000 abstract description 4
- 239000000956 alloy Substances 0.000 abstract description 4
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 abstract description 3
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- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 4
- 230000035515 penetration Effects 0.000 description 4
- 229910001200 Ferrotitanium Inorganic materials 0.000 description 3
- 229910008455 Si—Ca Inorganic materials 0.000 description 3
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- 229910052758 niobium Inorganic materials 0.000 description 3
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- 229910052720 vanadium Inorganic materials 0.000 description 3
- 238000005299 abrasion Methods 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
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- 150000004763 sulfides Chemical class 0.000 description 2
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- 230000009286 beneficial effect Effects 0.000 description 1
- 229910052918 calcium silicate Inorganic materials 0.000 description 1
- 239000000378 calcium silicate Substances 0.000 description 1
- OYACROKNLOSFPA-UHFFFAOYSA-N calcium;dioxido(oxo)silane Chemical compound [Ca+2].[O-][Si]([O-])=O OYACROKNLOSFPA-UHFFFAOYSA-N 0.000 description 1
- 239000004917 carbon fiber Substances 0.000 description 1
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- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 1
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- 229910052750 molybdenum Inorganic materials 0.000 description 1
- GUCVJGMIXFAOAE-UHFFFAOYSA-N niobium atom Chemical compound [Nb] GUCVJGMIXFAOAE-UHFFFAOYSA-N 0.000 description 1
- 229910021652 non-ferrous alloy Inorganic materials 0.000 description 1
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Landscapes
- Treatment Of Steel In Its Molten State (AREA)
Abstract
The invention belongs to the technical field of ferrous metallurgy, and particularly discloses steel for a battery pack support frame of a new energy electric automobile and a production method thereof. The invention provides the molten iron pre-desulfurization slag for the first time in the production process for changing slag system of low-sulfur steel at the end of refining, so as to realize the purpose of sulfur increase; the mode of replacing slag system at the end of refining and intermittently feeding silicon-calcium wire is adopted to realize the form and distribution of class A sulfide, in particular class A fine sulfide. The steel grade of the invention has excellent mechanical properties; through cost measurement, the steel grade of the invention has very high cost performance compared with nonferrous metals and alloys, and can completely replace the existing products.
Description
Technical Field
The invention belongs to the technical field of ferrous metallurgy, relates to the production and the production of steel types for replacing nonferrous alloys for supporting frames, and particularly relates to steel for a new energy electric automobile battery pack supporting frame and a production method thereof.
Background
The battery system is one of important core components in the new energy electric automobile, and the weight of the battery system accounts for about 10% -20%. According to researches, for the new energy electric automobile, every 10% of the weight of the automobile is reduced, the electricity consumption is reduced by 5.5%, the endurance mileage is increased by 5.5%, and meanwhile, the braking distance can be reduced due to the reduction of the weight of the automobile, so that the active safety performance of the automobile is improved. At present, battery materials for supporting new energy electric vehicles mainly comprise aluminum alloy, magnesium alloy, carbon fiber polymer and the like, wherein the aluminum alloy is widely applied in terms of high cost performance, but is influenced by severe working environments such as temperature change, collision, water vapor etching and the like, and higher requirements are put forward on a supporting structure system of the battery, particularly supporting parts in the battery structure system, and the parts are required to have the performance characteristics of high strength, high wear resistance, high toughness, corrosion resistance and the like. Because the strength and fatigue performance of the existing battery materials for supporting new energy electric vehicles such as aluminum alloy are relatively poor, the service life of the supporting materials is greatly limited, for example, the mechanical property yield strength of 6061 aluminum alloy battery trays is 218Mpa and the tensile strength is 239Mpa. Along with the extension of the service life of the battery of the new energy electric automobile, large and medium-sized automobiles such as SUVs and the like are gradually converted towards the new energy electric automobile, the battery pack of the type of automobile is bigger and heavier, and the battery support structure parts matched with the battery pack are required to have higher strength, especially key support parts, therefore, the mode of combining the steel key support structure parts with aluminum alloy is gradually adopted in the battery support material, and the long service life, the large size and the heavy quantization of the battery are dealt with by changing the mode of taking the existing single aluminum alloy and other materials as the battery support structure parts.
Under the great background of extremely vigorous competition in the current industry, the development of the steel for the steel key support structure part of the battery pack of the new energy electric automobile with high cost performance gradually becomes the necessary work in the field.
Disclosure of Invention
Aiming at the defects of the prior art, the invention aims to provide the steel for the battery pack support frame of the new energy electric automobile and the production method thereof.
The invention is realized by the following technical scheme:
the steel for the battery pack support frame of the new energy electric automobile comprises the following elements in percentage by mass: 0.12-0.15% of C, 0.50-0.60% of Si, 1.50-1.60% of Mn, 1.20-1.30% of Cr, less than or equal to 0.08% of Cu, less than or equal to 0.08% of Ni, less than or equal to 0.0040% of Mo, less than or equal to 0.0050% of V, 0.020-0.030% of Nb, less than or equal to 0.0040% of As, 0.025-0.040% of Al, less than or equal to 0.020% of P, 0.015-0.025% of S, less than or equal to 0.0008% of B, 0.012-0.025% of Ti, 0.0150-0.0200% of N, [ O ] < 20ppm, [ H ] < 2ppm, and the balance of Fe and unavoidable impurity elements; wherein Nb/Ti is controlled to be 1.0-2.5, and Cr/N is controlled to be 60-80.
Further, the steel for the battery pack support frame of the new energy electric automobile comprises the following elements in percentage by mass: 0.12-0.14% of C, 0.55-0.60% of Si, 1.55-1.60% of Mn, 1.20-1.26% of Cr, less than or equal to 0.08% of Cu, less than or equal to 0.08% of Ni, less than or equal to 0.0040% of Mo, less than or equal to 0.0050% of V, 0.020-0.028% of Nb, less than or equal to 0.0040% of As, 0.025-0.035% of Al, less than or equal to 0.020% of P, 0.015-0.020% of S, less than or equal to 0.0008% of B, 0.012-0.020% of Ti, 0.0180-0.0200% of N, [ O ] < 20ppm, [ H ] < 2ppm, and the balance of Fe and unavoidable impurity elements; wherein Nb/Ti is controlled to be 1.5-2.0, and Cr/N is controlled to be 60-70.
In the aspect of component design, the low-carbon design thought is adopted for realizing high toughness, and because the new energy electric automobile battery pack support frame is subjected to small-amplitude jumping in the advancing process of an automobile, the elastic performance of a product is met in order to buffer the jumping, the Si content is set in a relatively high range in the component design, but the Si content is higher, and adverse effects are brought to decarburization of the steel and the product in the processing process, so that the Si is set to be 0.5-0.6%; in the running process of the automobile, the support frame of the battery pack has certain abrasion due to the relative movement between the support frame and the battery pack, the tray and the inner wall of the automobile, cr/N is introduced into the design of components, and the abrasion resistance of the support frame is ensured through scientific and reasonable setting of the Cr/N; the microalloying element Nb is introduced into the mechanical property design of the steel grade, nb/Ti is provided for the first time, and the scientific and reasonable Nb/Ti design can well improve the surface quality of the Nb-containing steel. The production method matched with the component design adopts double vacuum treatment of RH+VD in the process flow to realize high purity and low B-class nonmetallic inclusion.
The reason why the chemical composition for the battery pack support frame of the energy electric vehicle is limited by the invention is specifically described below:
c: for steel, C is the most cost effective strengthening element than the alloying element, but a high C content increases the brittleness of the steel and deteriorates the toughness of the steel. Generally, the low-carbon steel (the C content is less than or equal to 0.25%) has better plastic toughness and relatively better welding performance. Considering the addition amount of the alloy elements of the steel grade and the requirements of the welding performance and high ductility and toughness of the processed product. So that the C content is 0.12-0.15%.
Si: considering that Si element can improve the elastic limit, yield strength, tensile strength and the like of steel, but the higher Si content can reduce plasticity, si can improve corrosion resistance and oxidation resistance, si can be dissolved in austenite or ferrite to strengthen the mechanical property of steel, and Si deoxidizer is also used for slag surface deoxidization in combination with the production method of the steel grade. Comprehensively considering, the Si content is determined to be 0.50-0.60%.
Mn: in the invention, mn is taken as one of main alloy elements, mn can be dissolved in ferrite to play a role in solid solution strength, pearlite is thinned in the cooling process after rolling, the strength and hardness of steel after rolling are improved, the Mn content is generally within 1.8%, the Mn element synchronously improves the toughness, namely, the strength is improved by improving the Mn content, and meanwhile, the toughness is also improved by the degree of dyke harbor. Therefore, the Mn content is determined to be 1.50-1.60%.
S: in general, S element is used as a harmful element in steel, in consideration of the fact that turning is needed after the steel grade is forged, in order to improve turning performance of machined parts, an existing common, economical and environment-friendly mode is adopted, namely, proper S element is added into the steel, meanwhile, the grade problem of sulfide inclusion is solved, the S content is set in a relatively low range, deterioration of A-type inclusion in the steel and castability of a continuous bead caused by the fact that the S content is high is prevented, and the S content is determined to be 0.015-0.025%.
Cr: cr element has solid solution strengthening effect, and improves the hot hardness, oxidation resistance, wear resistance and corrosion resistance of steel, in particular to wear resistance and corrosion resistance. Through research, cr and N are combined according to a certain proportion, and Cr can obviously improve the oxidation resistance and wear resistance of steel. And determining the Cr content to be 1.20-1.30%.
Nb and Ti: nb and Ti are very commonly used as two microalloying elements in non-quenched and tempered steel, and in the present invention, both elements are also used as microalloying, mainly for controlling forging height Wen Xijing. Nb can effectively control the grain size growth of austenite under the high temperature condition, and cooperates with constant temperature water penetration in the rolling process, and meanwhile, a certain amount of Ti is added into steel, and Nb/Ti is controlled for the first time to improve the surface quality of Nb element on a casting blank. The Nb and Ti contents are respectively determined to be 0.020-0.030% and 0.012-0.025%, wherein Nb/Ti is set to be 1.0-2.5.
Al: in the steel grades of the invention aluminium is mainly used for deoxidizing and controlling the oxygen content in the molten steel. When the Als content in the molten steel is usually 0.020-0.050%, the oxygen content in balance with the molten steel is only 3-7 ppm, and in the comprehensive consideration, the Al content is designed to be 0.025-0.040% in the composition design.
N: for common steel types, the aging phenomenon of N element has a harmful effect on the steel, and N is not added into the common steel. According to the invention, the added N is matched with the added Cr, and the wear resistance and corrosion resistance of the steel can be obviously improved through reasonable control of Cr/N, and the content of N is determined to be 0.0150-0.0200%, wherein the Cr/N is set to be 60-80.
In order to stabilize the mechanical properties of the steel grade, ni, cu, mo, V, P, B, as, [ O ] and [ H ] are controlled as residual elements, and the residual content is required: ni is less than or equal to 0.08%, cu is less than or equal to 0.08%, V is less than or equal to 0.0040%, mo is less than or equal to 0.0040%, P is less than or equal to 0.020%, B is less than or equal to 0.0008%, as is less than or equal to 0.0040%, O is less than or equal to 20ppm, and H is less than or equal to 2ppm. In particular to the control of the content of three elements of Mo, V and B.
The invention further improves the scheme as follows:
a production method of steel for a battery pack support frame of a new energy electric automobile comprises the following steps:
1) Pre-desulphurisation of molten iron
Controlling the temperature of molten iron to 1250-1300 ℃, adopting a composite pre-desulfurization treatment mode combining injection and mechanical stirring to ensure that the sulfur content range in molten iron after molten iron desulfurization is 0.030-0.040%, taking dry high-purity nitrogen as a carrier, and spraying granular magnesium into the molten iron through a central pipeline of a mechanical stirrer;
2) Converter smelting
Adopting scrap steel and molten iron as raw materials, carrying out rough smelting in a top-bottom combined blown converter with a sublance, adding lime into the converter twice, controlling chemical components at a smelting end point to be mainly C0.03-0.05%, P to be less than or equal to 0.018%, and controlling the temperature at the smelting end point to be 1700-1720 ℃; after tapping 10 tons, sequentially adding metal manganese, low-carbon ferrochrome, ferrosilicon, premelted refining slag, lime and fluorite into a ladle; the main chemical components of the RH furnace are controlled to meet the requirements of 0.03-0.05% of C, 0.3-0.40% of Si, 1.10-1.20% of Mn and 0.90-1.00% of Cr;
3) Argon blowing station large stirring
After tapping, rapidly transferring the ladle to an argon blowing station, immediately opening bottom blowing argon for large stirring, rapidly adding a heat preservation agent to the slag surface after stirring, controlling the thickness of the heat preservation agent on the slag surface to be 15-25 mm, continuously soft blowing for 3-4 minutes at the argon blowing station, and controlling the argon flow to be 150-200 NL/min;
4) RH vacuum circulation degassing
After molten steel is treated under the low vacuum degree, adding low nitrogen carbon powder into the molten steel through a feed bin, increasing the vacuum degree after the carbon powder is added, continuing to treat the molten steel under the high vacuum degree, adding aluminum particles into the molten steel through the feed bin after the treatment is finished, and finally treating the molten steel under the high vacuum degree;
5) Ladle refining
The method comprises the steps of (1) deoxidizing a carbide slag surface in the early stage of smelting, wherein the main chemical components of molten steel in the middle stage of smelting meet the requirements of C0.12-0.14, si 0.47-0.52%, mn 1.42-1.48% and Cr 1.18-1.23%, adding ferroniobium and ferrovanadium into the molten steel in the middle and later stages of smelting, after other chemical components except S and Mn are well regulated, pouring 1/2 of steel slag, adding the hot pre-desulfurization slag just generated onto the slag surface, adding special pre-melting refining slag, deoxidizing the slag surface by using high-purity silicon carbide in the subsequent refining process, and feeding a sulfur line into the molten steel according to the S content in the molten steel in the final stage of refining, wherein the S content is controlled to be 0.025-0.035;
6) VD vacuum refining
Intermittently feeding silicon-calcium wires into the molten steel after the VD vacuum refining treatment is finished, wherein each time is 20 meters per time, each time is separated by 2 minutes, and soft blowing is carried out for 15-20 minutes after the wire feeding is finished;
7) Continuous casting
The casting is completed by an arc continuous casting machine, argon is adopted for whole-course protection in the casting process, the superheat degree of molten steel is controlled at 20-30 ℃, the casting section is 200mm by 200mm, the pulling speed is 1.3min, and the steel billet is cooled by wind-proof piling;
8) Steel rolling
Cold charging the steel billet into a furnace, controlling the compression ratio to be more than or equal to 7 and controlling the heating furnace in four sections; the rolling process of continuous rolling, water penetrating and KOCKS is adopted, after rolling, the steel is slowly cooled in a pit, and the pit entering temperature is controlled at 300-400 ℃.
The invention further improves the scheme as follows:
in the step 1), if the sulfur content of molten iron is less than or equal to 0.040%, the molten iron is not subjected to pre-desulfurization treatment, and only slag skimming treatment is performed at a pre-desulfurization station to stabilize the sulfur content of the molten iron.
Further, in the step 2), 50% of lime is added into the furnace after smelting is started, 1/3 of dephosphorization slag is poured out after low-temperature smelting is finished when the temperature of molten iron in the furnace is less than or equal to 1490 ℃, and the rest 50% of lime is added into the furnace after smelting is performed for 5 minutes; any aluminum deoxidizer, calcium carbide deoxidizer and silicon carbide deoxidizer are forbidden to be added into molten steel in the tapping process.
In the step 3), the argon flow is controlled to be 700-900 NL/min in the process of large stirring, and the time is 4-5 minutes.
Further, in the step 4), the specific process of the RH vacuum circulation degassing is as follows: molten steel is treated for 1-3 min and 2-4 min respectively under the low vacuum degree of 1000pa and 500pa, after the low vacuum degree treatment is finished, low nitrogen carbon powder is added into the molten steel through a feed bin for 0.5-1.5Kg/t, after the carbon powder is added, the molten steel is treated for 4-6 min under the vacuum degree of less than 100pa, the molten steel is treated for 6-8 min under the high vacuum degree of less than 60pa, aluminum particles are added into the molten steel through the feed bin for 0.5-1.0Kg/t after the treatment is finished, and finally the molten steel is treated for 2-5 min under the high vacuum degree of less than 60 pa.
Further, the flow rate of bottom blowing gas is controlled at 40-80 NL/min during soft blowing in the RH vacuum circulation degassing process.
Further, in step 5), the special premelted refining slag is composed of the following components in percentage: 45-50% of W (CaO) and 45-50% of W (SiO) 2 ) 20~25%、W(MgO) 5~6%、W(Al 2 O 3 ) 15-20% of special premelted refining slag, wherein the adding amount of the special premelted refining slag is 0.4-0.6Kg/t; the adding amount of the pre-desulfurization slag is 0.5-1.5Kg/t.
In step 6), the vacuum degree is less than or equal to 67pa, the time is 8-12 minutes, and the argon flow is controlled at 35-70 NL/min during VD vacuum refining treatment.
Further, in step 8), the four-stage control of the heating furnace specifically includes: heating the first section to 900-950 ℃, the second section to 1000-1050 ℃, the third section 1160-1200 ℃, and the soaking section to 1100-1130 DEG C
Further, in the step 8), the rolling reduction of KOCKS is 13-18%, the temperature of KOCKS is 810-830 ℃, and the final rolling temperature of steel is 730-800 ℃.
In the production process, on the basis of the pre-desulfurization of the molten iron, the pre-desulfurization of the molten iron is completed in a mode of combining injection and mechanical stirring; in an argon protection device, large stirring operation is realized, and conditions are created for the later-stage vacuum treatment and the earlier-stage floating of large-particle nonmetallic inclusion; the molten iron pre-desulfurization slag is firstly provided to be used for changing slag system of low-sulfur steel at the end of refining, so that the purpose of sulfur increase is realized; the form and distribution of class A sulfides, in particular class A fine sulfides, are realized by adopting a mode of replacing a slag system at the end of refining, intermittently feeding a calcium silicate wire, combining weak first cold water quantity with strong second cold water quantity; the continuous rolling, water passing and KOCKS process is adopted in rolling, and after continuous rolling and before KOCKS finish rolling, the strip-shaped tissue is ensured to be at a relatively low level by the KOCKS temperature, KOCKS rolling reduction and finish rolling temperature. The measured values of the mechanical properties of the steel grade are as follows: the lower yield strength is 430-480 Mpa, the tensile strength is 660-691 Mpa, the elongation is 18-22%, the area shrinkage is 57-68%, the normal temperature U-shaped impact power is 180-210J, the banded structure is less than or equal to 2.0 level, and the class A fine system of the nonmetallic inclusion is less than or equal to 2.5 level; through cost measurement, the steel grade of the invention has very high cost performance compared with nonferrous metals and alloys, and can completely replace the existing products.
The beneficial effects of the invention are as follows:
according to the steel for the battery pack support frame of the new energy electric automobile, the low-carbon thought is determined on the basis of component design according to the action of the battery pack support frame, the toughness and the plasticity of a product are guaranteed, and meanwhile, cr/N is introduced in consideration of corrosion resistance and wear resistance.
Secondly, according to the steel for the battery pack support frame of the new energy electric automobile, trace Nb is added on a high manganese component design way to refine austenite grain size, and meanwhile, ti is utilized, and proper Nb/Ti is utilized to improve the surface quality of the steel containing niobium.
Thirdly, the production method of the steel for the battery pack support frame of the new energy electric automobile creatively utilizes the just-produced pre-desulfurization slag, and adds the pre-desulfurization slag into a refining slag system to increase sulfur and adjust the slag system.
Fourth, the production method of the steel for the battery pack support frame of the new energy electric automobile adopts double vacuum treatment of molten steel of RH+VD, and realizes RH strong vacuum degassing and VD weak vacuum refining of the molten steel.
Fifthly, according to the production method of the steel for the battery pack support frame of the new energy electric automobile, part of original alkaline refining slag is intentionally replaced in the later period of refining, replacement of slag systems is achieved, and the sulfur content of molten steel is guaranteed to meet the requirements.
Sixth, according to the production method of the steel for the battery pack support frame of the new energy electric automobile, continuous rolling, water penetrating and KOCKS rolling processes are adopted in rolling, the rolling reduction of the KOCKS is controlled to be 13-18%, the KOCKS temperature is 810-830 ℃, and the final rolling temperature is 730-800 ℃.
Seventh, the invention relates to a new energy electric automobile battery pack support frame steel and a production method thereof, the steel has the actual measurement values of mechanical properties: the lower yield strength is 430-480 Mpa, the tensile strength is 660-691 Mpa, the elongation is 18-22%, the area shrinkage is 57-68%, the normal temperature U-shaped impact power is 180-210J, the band-shaped structure is less than or equal to 2.0 level, and the class A fine system of the nonmetallic inclusion is less than or equal to 2.5 level.
Drawings
FIG. 1 is a band chart of the steel grade produced in example 1;
FIG. 2 is a drawing showing nonmetallic inclusion of the steel grade produced in example 1;
FIG. 3 is a band chart of the steel grade produced in example 2;
FIG. 4 shows nonmetallic inclusion of the steel grade of example 2;
FIG. 5 is a band chart of the steel grade produced in example 3;
FIG. 6 shows nonmetallic inclusions in the steel grade produced in example 3.
Detailed Description
The present invention will be described in detail with reference to specific examples.
Example 1
The embodiment provides steel for a battery pack support frame of a new energy electric automobile, which comprises the following elements in percentage by mass: 0.12% of C, 0.57% of Si, 1.58% of Mn, 1.24% of Cr, 0.03% of Cu, 0.04% of Ni, 0.0028% of Mo, 0.0033% of V, 0.025% of Nb, 0.0036% of As, 0.032% of Al, 0.017% of P, 0.017% of S, 0.0006% of B, 0.016% of Ti, 0.0189% of N, [ O ] 12ppm, [ H ]1.0ppm, and the balance of Fe and unavoidable impurity elements; wherein Nb/Ti is controlled to be 1.56 and Cr/N is controlled to be 65.6.
1) Pre-desulphurisation of molten iron
The temperature of molten iron is 1256 ℃, the sulfur content of the molten iron is 0.035%, and the molten iron is not subjected to pre-desulfurization treatment;
2) Converter smelting
The method comprises the steps of adopting scrap steel and molten iron as raw materials, carrying out rough smelting in a top-bottom combined blown converter with a sublance according to the molten iron ratio of 93%, adding lime into the converter twice, adding 50% of lime into the converter after smelting is started, pouring 1/3 dephosphorization slag after low-temperature smelting (the temperature of molten iron in the converter is less than or equal to 1490 ℃) is finished, adding the rest 50% of lime into the converter after smelting for 5 minutes, and controlling the chemical components at the smelting end point to be mainly as follows: c0.040%, P less than or equal to 0.016%, and the smelting end temperature is controlled mainly in the following steps: 1701 ℃. After tapping 10 tons, 11.5Kg/t of manganese metal, 17.6Kg/t of low-carbon ferrochrome, 3.6Kg/t of ferrosilicon, premelted refining slag, lime and fluorite are added into the ladle in sequence. Any aluminum deoxidizer, calcium carbide deoxidizer, silicon carbide deoxidizer and the like are forbidden to be added into molten steel in the tapping process, and the main chemical components of the RH furnace are as follows: 0.06% of C, 0.33% of Si, 1.16% of Mn and 0.94% of Cr.
3) Argon blowing station large stirring
After tapping, rapidly transferring the ladle to an argon blowing station, immediately opening bottom blowing argon, and stirring for 5 minutes, wherein the argon flow is controlled at 800NL/min in the process. After the argon is stirred greatly, a heat preservation agent is added to the slag surface rapidly, the thickness of the heat preservation agent on the slag surface is controlled to be 20mm, soft blowing is continued for 4 minutes at an argon blowing station, and the flow of the argon is controlled to be 160NL/min.
4) RH vacuum circulation degassing
Molten steel is treated for 2 minutes and 3 minutes respectively under the low vacuum degree of 1000pa and 500pa, after the treatment of the low vacuum degree is finished, low nitrogen carbon powder is added into the molten steel through a feed bin for 1Kg/t, after the carbon powder is added, the molten steel is treated for 5 minutes under the vacuum degree of 100pa, the molten steel is treated for 7 minutes under the high vacuum degree of less than 60pa, aluminum particles are added into the molten steel through the feed bin for 0.8Kg/t after the treatment is finished, and finally the molten steel is treated for 3 minutes under the high vacuum degree of less than 60 pa;
5) Ladle refining
The carbide slag surface is used for deoxidizing in the early stage of smelting until the main chemical components of molten steel in the middle stage of smelting meet the requirements of C0.12, si 0.48%, mn 1.42% and Cr 1.19%, and 0.27Kg/t of ferrocolumbium and 0.35Kg/t of ferrotitanium are added into the molten steel in the middle and later stages of smelting. After other chemical components except S and Mn are well regulated, pouring out 1/2 of steel slag, adding the hot pre-desulfurization slag just generated onto the slag surface, adding the pre-desulfurization slag according to 1Kg/t, and adding 0.5Kg/t of special pre-melting refining slag: 45-50% of W (CaO) and 45-50% of W (SiO) 2 ) 20~25%、W(MgO) 5~6%、W(Al 2 O 3 ) 15-20%. High purity silicon carbide (Wsio) is used in subsequent refining processes 2 99%) was subjected to slag surface deoxidation, and at the end of refining, a sulfur line was fed to the molten steel at 100m in accordance with the S content in the molten steel, and the S content was controlled at 0.027%.
6) VD vacuum refining
The molten steel is treated for 10 minutes under the condition that the vacuum degree is less than or equal to 67pa by VD vacuum refining treatment, the argon flow is controlled at 60NL/min in the vacuum treatment process, and after the VD vacuum treatment is finished, the molten steel is intermittently fed with the Si-Ca wire 20 m/time for 2 minutes each time, and the wire is soft blown for 18 minutes after being fed.
7) Continuous casting
The casting is completed by an arc continuous casting machine, argon is adopted for whole-course protection in the casting process, the superheat degree of molten steel is 27 ℃, the casting section is 200mm by 200mm, the pulling speed is 1.3min, and the steel billet is cooled by wind-proof piling;
8) Steel rolling
The billet is cold-charged into a furnace, the compression ratio is 31.9, the rolling specification is 40mm, the four-section control is performed on the heating furnace, the temperature of the heating furnace is 900-950 ℃, the temperature of the heating furnace is 1000-1050 ℃, the temperature of the heating furnace is 1160-1200 ℃, the temperature of the soaking furnace is 1100-1130 ℃, and the initial rolling temperature is 1032 ℃. The rolling process of continuous rolling, water penetration and KOCKS is adopted, the rolling reduction of KOCKS is 16%, the rolling temperature of KOCKS is 812 ℃, the final rolling temperature of steel is 778 ℃, the steel is slowly cooled in pits, and the pit entering temperature is controlled at 320 ℃.
Mechanical properties and tape-like structures and nonmetallic inclusions were tested by taking longitudinal tensile specimens and impact specimens at half radius according to GB/T228.1 and GB/T229, and specific test results are shown in tables 1, 2, FIGS. 1 and 2, respectively.
TABLE 1 mechanical Properties
TABLE 2 nonmetallic inclusion and band structure/grade
Example 2
The embodiment provides steel for a battery pack support frame of a new energy electric automobile, which comprises the following elements in percentage by mass: 0.12% of C, 0.59% of Si, 1.56% of Mn, 1.23% of Cr, 0.03% of Cu, 0.02% of Ni, 0.0035% of Mo, 0.0047% of V, 0.024% of Nb, 0.0029% of As, 0.028% of Al, 0.015% of P, 0.016% of S, 0.0006% of B, 0.014% of Ti, 0.0190% of N, [ 10ppm of O, [ 0.9ppm of H ] and the balance of Fe and unavoidable impurity elements; wherein Nb/Ti is controlled to be 1.71 and Cr/N is controlled to be 64.73.
1) Pre-desulphurisation of molten iron
The temperature of molten iron is 1263 ℃, the sulfur content of the molten iron is 0.046%, a brand new compound pre-desulfurization treatment mode combining injection and mechanical stirring is adopted, dry high-purity nitrogen (the N2 content is more than 99.99%) is taken as a carrier, 0.16Kg/t of granular magnesium is injected into the molten iron through a central pipeline of a mechanical stirrer, and the sulfur content in the molten iron after desulfurization is 0.032%;
2) Converter smelting
Waste steel and molten iron are used as raw materials, the molten iron ratio is 91%, coarse smelting is carried out in a top-bottom combined blown converter with a sublance, lime is added into the converter twice, 50% of the lime is added into the converter after smelting is started, 1/3 dephosphorization slag is poured out after low-temperature smelting (the temperature of molten iron in the converter is less than or equal to 1490 ℃) is finished, after 5 minutes of smelting, the rest 50% of lime is added into the converter, and the chemical components of the smelting end point are mainly controlled as follows: c0.040%, P is less than or equal to 0.013%, and the smelting end temperature is controlled mainly in the following steps: 1714 ℃. After tapping 10 tons, adding 11.3Kg/t of manganese metal, 18Kg/t of low-carbon ferrochrome, 3.7Kg/t of ferrosilicon, premelted refining slag, lime and fluorite into the ladle in sequence. Any aluminum deoxidizer, calcium carbide deoxidizer, silicon carbide deoxidizer and the like are forbidden to be added into molten steel in the tapping process, and the main chemical components of the RH furnace are as follows: 0.05% of C, 0.35% of Si, 1.14% of Mn and 0.93% of Cr.
3) Argon blowing station large stirring
After tapping, rapidly transferring the ladle to an argon blowing station, immediately opening bottom blowing argon, and stirring for 4 minutes, wherein the argon flow is controlled at 800NL/min in the process. After the argon is stirred greatly, a heat preservation agent is added to the slag surface rapidly, the thickness of the heat preservation agent on the slag surface is controlled to be 20mm, soft blowing is continued for 4 minutes at an argon blowing station, and the flow of the argon is controlled to be 160NL/min.
4) RH vacuum circulation degassing
Molten steel is treated for 2 minutes and 3 minutes respectively under the low vacuum degree of 1000pa and 500pa, after the treatment of the low vacuum degree is finished, low nitrogen carbon powder is added into the molten steel through a feed bin for 1Kg/t, after the carbon powder is added, the molten steel is treated for 5 minutes under the vacuum degree of 100pa, the molten steel is treated for 7 minutes under the high vacuum degree of less than 60pa, aluminum particles are added into the molten steel through the feed bin for 0.8Kg/t after the treatment is finished, and finally the molten steel is treated for 3 minutes under the high vacuum degree of less than 60 pa;
5) Ladle refining
The carbide slag surface is used for deoxidizing in the early stage of smelting until the main chemical components of molten steel in the middle stage of smelting meet the requirements of C0.12, si 0.52%, mn 1.45% and Cr 1.21%, and 0.26Kg/t of ferrocolumbium and 0.30Kg/t of ferrotitanium are added into the molten steel in the middle and later stages of smelting. After other chemical components except S and Mn are well regulated, pouring out 1/2 of steel slag, adding the hot pre-desulfurization slag just generated onto the slag surface, adding the pre-desulfurization slag according to 1Kg/t, and adding 0.5Kg/t of special pre-melting refining slag: 45-50% of W (CaO) and 45-50% of W (SiO) 2 ) 20~25%、W(MgO) 5~6%、W(Al 2 O 3 ) 15-20%. High purity silicon carbide (Wsio) is used in subsequent refining processes 2 99%) was subjected to slag surface deoxidation, and at the end of refining, a sulfur line 120m was fed to the molten steel in accordance with the S content in the molten steel, and the S content was controlled to 0.030%.
6) VD vacuum refining
The molten steel is treated for 10 minutes under the condition that the vacuum degree is less than or equal to 67pa by VD vacuum refining treatment, the argon flow is controlled at 60NL/min in the vacuum treatment process, and after the VD vacuum treatment is finished, the molten steel is intermittently fed with the Si-Ca wire 20 m/time for 2 minutes each time, and the wire is soft blown for 18 minutes after being fed.
7) Continuous casting
The arc continuous casting machine finishes casting, argon is adopted for whole-course protection in the casting process, the superheat degree of molten steel is controlled at 30 ℃, the casting section is 200mm by 200mm, the pulling speed is 1.3min, the steel billet is cooled by wind-proof heap,
8) Steel rolling
The billet is cold-charged into a furnace, the compression ratio is 20.4, the rolling specification is 50mm, the four-section control is performed on the heating furnace, the temperature of the heating furnace is 900-950 ℃, the temperature of the heating furnace is 1000-1050 ℃, the temperature of the heating furnace is 1160-1200 ℃, the temperature of the soaking furnace is 1100-1130 ℃, and the initial rolling temperature is 1041 ℃. The rolling process of continuous rolling, water penetration and KOCKS is adopted, the rolling reduction of KOCKS is 15%, the KOCKS temperature is 821 ℃, the steel finish rolling temperature is 785 ℃, the steel is slowly cooled in pits, and the pit entering temperature is controlled at 350 ℃.
Mechanical properties and tape-like structures and nonmetallic inclusions were examined by taking longitudinal tensile specimens and impact specimens at half radius according to GB/T228.1 and GB/T229, and specific examination results are shown in tables 3, 4, FIG. 3 and FIG. 4, respectively.
TABLE 3 mechanical Properties
TABLE 4 nonmetallic inclusion and band structure/grade
Example 3
The embodiment provides steel for a battery pack support frame of a new energy electric automobile, which comprises the following elements in percentage by mass: 0.13% of C, 0.57% of Si, 1.56% of Mn, 1.25% of Cr, 0.05% of Cu, 0.03% of Ni, 0.0040% of Mo, 0.0037% of V, 0.023% of Nb, 0.0038% of As, 0.032% of Al, 0.017% of P, 0.018% of S, 0.0007% of B, 0.015% of Ti, 0.0191% of N, [ O ] 9ppm, [ H ]1.0ppm, and the balance of Fe and unavoidable impurity elements; wherein Nb/Ti is controlled to be 1.53 and Cr/N is controlled to be 65.45.
1) Pre-desulphurisation of molten iron
The temperature of molten iron is 1270 ℃, the sulfur content of the molten iron is 0.050%, a brand new compound pre-desulfurization treatment mode combining injection and mechanical stirring is adopted, dry high-purity nitrogen (the N2 content is more than 99.99%) is taken as a carrier, 0.14Kg/t of granular magnesium is injected into the molten iron through a central pipeline of a mechanical stirrer, and the sulfur content in the molten iron after desulfurization is 0.039%;
2) Converter smelting
The method comprises the steps of adopting scrap steel and molten iron as raw materials, carrying out rough smelting in a top-bottom combined blown converter with a sublance in a ratio of 92%, adding lime into the converter twice, adding 50% of lime into the converter after smelting is started, pouring 1/3 dephosphorization slag after low-temperature smelting (the temperature of molten iron in the converter is less than or equal to 1490 ℃) is finished, adding the rest 50% of lime into the converter after smelting for 5 minutes, and controlling the chemical components of the smelting end point to be mainly as follows: c0.050%, P is less than or equal to 0.015%, and smelting end temperature is controlled mainly in: 1708 ℃. After tapping 10 tons, adding 11.3Kg/t of manganese metal, 19Kg/t of low-carbon ferrochrome, 3.6Kg/t of ferrosilicon, premelted refining slag, lime and fluorite into the ladle in sequence. Any aluminum deoxidizer, calcium carbide deoxidizer, silicon carbide deoxidizer and the like are forbidden to be added into molten steel in the tapping process, and the main chemical components of the RH furnace are as follows: 0.07% of C, 0.32% of Si, 1.13% of Mn and 0.96% of Cr.
3) Argon blowing station large stirring
After tapping, rapidly transferring the ladle to an argon blowing station, immediately opening bottom blowing argon, and stirring for 4 minutes, wherein the argon flow is controlled at 800NL/min in the process. After the argon is stirred greatly, a heat preservation agent is added to the slag surface rapidly, the thickness of the heat preservation agent on the slag surface is controlled to be 20mm, soft blowing is continued for 4 minutes at an argon blowing station, and the flow of the argon is controlled to be 160NL/min.
4) RH vacuum circulation degassing
Molten steel is treated for 2 minutes and 3 minutes respectively under the low vacuum degree of 1000pa and 500pa, after the treatment of the low vacuum degree is finished, low nitrogen carbon powder is added into the molten steel through a feed bin for 1Kg/t, after the carbon powder is added, the molten steel is treated for 5 minutes under the vacuum degree of 100pa, the molten steel is treated for 7 minutes under the high vacuum degree of less than 60pa, aluminum particles are added into the molten steel through the feed bin for 0.8Kg/t after the treatment is finished, and finally the molten steel is treated for 3 minutes under the high vacuum degree of less than 60 pa;
5) Ladle refining
The carbide slag surface is used for deoxidizing in the early stage of smelting until the main chemical components of molten steel in the middle stage of smelting meet the requirements of C0.13, si 0.51%, mn 1.44% and Cr 1.18%, and 0.26Kg/t of ferrocolumbium and 0.32Kg/t of ferrotitanium are added into the molten steel in the middle and later stages of smelting. After other chemical components except S and Mn are well regulated, pouring out 1/2 of steel slag, adding the hot pre-desulfurization slag just generated onto the slag surface, adding the pre-desulfurization slag according to 1Kg/t, and adding 0.5Kg/t of special pre-melting refining slag: 45-50% of W (CaO) and 45-50% of W (SiO) 2 ) 20~25%、W(MgO) 5~6%、W(Al 2 O 3 ) 15-20%. High purity silicon carbide (Wsio) is used in subsequent refining processes 2 99%) was subjected to slag surface deoxidation, and at the end of refining, a sulfur line 80m was fed to the molten steel in accordance with the S content in the molten steel, and the S content was controlled to 0.035%.
6) VD vacuum refining
The molten steel is treated for 10 minutes under the condition that the vacuum degree is less than or equal to 67pa by VD vacuum refining treatment, the argon flow is controlled at 60NL/min in the vacuum treatment process, and after the VD vacuum treatment is finished, the molten steel is intermittently fed with the Si-Ca wire 20 m/time for 2 minutes each time, and the wire is soft blown for 18 minutes after being fed.
7) Continuous casting
The arc continuous casting machine finishes casting, argon is adopted for whole-course protection in the casting process, the superheat degree of molten steel is controlled at 29 ℃, the casting section is 200mm by 200mm, the pulling speed is 1.3min, the steel billet is cooled by wind-proof heap,
8) Steel rolling
The billet is cold-charged into a furnace, the compression ratio is 20.4, the rolling specification is 50mm, the four-section control is performed on the heating furnace, the temperature of the heating furnace is 900-950 ℃ for the first section, the temperature of the heating furnace is 1000-1050 ℃ for the second section, the temperature of the heating furnace is 1160-1200 ℃ for the third section, the temperature of the soaking section is 1100-1130 ℃, and the initial rolling temperature is 1038 ℃. The rolling process of continuous rolling, water penetration and KOCKS is adopted, the rolling reduction of KOCKS is 14%, the KOCKS temperature is 817 ℃, the steel finishing temperature is 781 ℃, the steel is slowly cooled in a pit, and the pit entering temperature is controlled at 360 ℃.
Mechanical properties and tape-like structures and nonmetallic inclusions were examined by taking longitudinal tensile specimens and impact specimens at half radius according to GB/T228.1 and GB/T229, and specific examination results are shown in tables 5, 6, FIGS. 5 and 6, respectively.
TABLE 5 mechanical Properties
TABLE 6 nonmetallic inclusion and band structure/grade
The foregoing embodiments are merely illustrative of the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the present invention and to implement the same, not to limit the scope of the present invention. All equivalent changes or modifications made according to the spirit of the present invention should be included in the scope of the present invention.
Claims (10)
1. The steel for the new energy electric automobile battery pack support frame is characterized by comprising the following elements in percentage by mass: 0.12-0.15% of C, 0.50-0.60% of Si, 1.50-1.60% of Mn, 1.20-1.30% of Cr, less than or equal to 0.08% of Cu, less than or equal to 0.08% of Ni, less than or equal to 0.0040% of Mo, less than or equal to 0.0050% of V, 0.020-0.030% of Nb, less than or equal to 0.0040% of As, 0.025-0.040% of Al, less than or equal to 0.020% of P, 0.015-0.025% of S, less than or equal to 0.0008% of B, 0.012-0.025% of Ti, 0.0150-0.0200% of N, [ O ] < 20ppm, [ H ] < 2ppm, and the balance of Fe and unavoidable impurity elements; wherein Nb/Ti is controlled to be 1.0-2.5, and Cr/N is controlled to be 60-80.
2. The steel for a battery pack support frame of a new energy electric vehicle according to claim 1, wherein: the composite material consists of the following elements in percentage by mass: 0.12-0.14% of C, 0.55-0.60% of Si, 1.55-1.60% of Mn, 1.20-1.26% of Cr, less than or equal to 0.08% of Cu, less than or equal to 0.08% of Ni, less than or equal to 0.0040% of Mo, less than or equal to 0.0050% of V, 0.020-0.028% of Nb, less than or equal to 0.0040% of As, 0.025-0.035% of Al, less than or equal to 0.020% of P, 0.015-0.020% of S, less than or equal to 0.0008% of B, 0.012-0.020% of Ti, 0.0180-0.0200% of N, [ O ] < 20ppm, [ H ] < 2ppm, and the balance of Fe and unavoidable impurity elements; wherein Nb/Ti is controlled to be 1.5-2.0, and Cr/N is controlled to be 60-70.
3. The method for producing a steel for a battery pack support frame of a new energy electric vehicle according to claim 1 or 2, comprising the steps of:
1) Pre-desulphurisation of molten iron
Controlling the temperature of molten iron to 1250-1300 ℃, adopting a composite pre-desulfurization treatment mode combining injection and mechanical stirring to ensure that the sulfur content range in molten iron after molten iron desulfurization is 0.030-0.040%, taking dry high-purity nitrogen as a carrier, and spraying granular magnesium into the molten iron through a central pipeline of a mechanical stirrer;
2) Converter smelting
Adopting scrap steel and molten iron as raw materials, carrying out rough smelting in a top-bottom combined blown converter with a sublance, adding lime into the converter twice, controlling chemical components at a smelting end point to be mainly C0.03-0.05%, P to be less than or equal to 0.018%, and controlling the temperature at the smelting end point to be 1700-1720 ℃; after tapping 10 tons, sequentially adding metal manganese, low-carbon ferrochrome, ferrosilicon, premelted refining slag, lime and fluorite into a ladle; the main chemical components of the RH furnace are controlled to meet the requirements of 0.03-0.05% of C, 0.3-0.40% of Si, 1.10-1.20% of Mn and 0.90-1.00% of Cr;
3) Argon blowing station large stirring
After tapping, rapidly transferring the ladle to an argon blowing station, immediately opening bottom blowing argon for large stirring, rapidly adding a heat preservation agent to the slag surface after stirring, controlling the thickness of the heat preservation agent on the slag surface to be 15-25 mm, continuously soft blowing for 3-4 minutes at the argon blowing station, and controlling the argon flow to be 150-200 NL/min;
4) RH vacuum circulation degassing
After molten steel is treated under the low vacuum degree, adding low nitrogen carbon powder into the molten steel through a feed bin, increasing the vacuum degree after the carbon powder is added, continuing to treat the molten steel under the high vacuum degree, adding aluminum particles into the molten steel through the feed bin after the treatment is finished, and finally treating the molten steel under the high vacuum degree;
5) Ladle refining
The method comprises the steps of (1) deoxidizing a carbide slag surface in the early stage of smelting, wherein the main chemical components of molten steel in the middle stage of smelting meet the requirements of C0.12-0.14, si 0.47-0.52%, mn 1.42-1.48% and Cr 1.18-1.23%, adding ferroniobium and ferrovanadium into the molten steel in the middle and later stages of smelting, after other chemical components except S and Mn are well regulated, pouring 1/2 of steel slag, adding the hot pre-desulfurization slag just generated onto the slag surface, adding special pre-melting refining slag, deoxidizing the slag surface by using high-purity silicon carbide in the subsequent refining process, and feeding a sulfur line into the molten steel according to the S content in the molten steel in the final stage of refining, wherein the S content is controlled to be 0.025-0.035;
6) VD vacuum refining
Intermittently feeding silicon-calcium wires into the molten steel after the VD vacuum refining treatment is finished, wherein each time is 20 meters per time, each time is separated by 2 minutes, and soft blowing is carried out for 15-20 minutes after the wire feeding is finished;
7) Continuous casting
The casting is completed by an arc continuous casting machine, argon is adopted for whole-course protection in the casting process, the superheat degree of molten steel is controlled at 20-30 ℃, the casting section is 200mm by 200mm, the pulling speed is 1.3min, and the steel billet is cooled by wind-proof piling;
8) Steel rolling
Cold charging the steel billet into a furnace, controlling the compression ratio to be more than or equal to 7, heating the furnace by four sections, wherein the temperature of the first section is 900-950 ℃, the temperature of the second section is 1000-1050 ℃, the temperature of the third section is 1160-1200 ℃, and the temperature of the soaking section is 1100-1130 ℃; the rolling process of continuous rolling, water penetrating and KOCKS is adopted, after rolling, the steel is slowly cooled in a pit, and the pit entering temperature is controlled at 300-400 ℃.
4. The method for producing the steel for the battery pack support frame of the new energy electric automobile according to claim 3, which is characterized in that: in the step 2), 50% of lime is added into the furnace after smelting is started, 1/3 dephosphorization slag is poured out after low-temperature smelting is finished when the temperature of molten iron in the furnace is less than or equal to 1490 ℃, and the rest 50% of lime is added into the furnace after smelting is performed for 5 minutes; any aluminum deoxidizer, calcium carbide deoxidizer and silicon carbide deoxidizer are forbidden to be added into molten steel in the tapping process.
5. The method for producing the steel for the battery pack support frame of the new energy electric automobile according to claim 3, which is characterized in that: in the step 3), the argon flow is controlled at 700-900 NL/min in the process of large stirring, and the time is 4-5 minutes.
6. The method for producing the steel for the battery pack support frame of the new energy electric automobile according to claim 3, which is characterized in that: in the step 4), the specific process of RH vacuum circulation degassing is as follows: molten steel is treated for 1-3 min and 2-4 min respectively under the low vacuum degree of 1000pa and 500pa, after the low vacuum degree treatment is finished, low nitrogen carbon powder is added into the molten steel through a feed bin for 0.5-1.5Kg/t, after the carbon powder is added, the molten steel is treated for 4-6 min under the vacuum degree of less than 100pa, the molten steel is treated for 6-8 min under the high vacuum degree of less than 60pa, aluminum particles are added into the molten steel through the feed bin for 0.5-1.0Kg/t after the treatment is finished, and finally the molten steel is treated for 2-5 min under the high vacuum degree of less than 60 pa.
7. The production method of the steel for the battery pack support frame of the new energy electric automobile, which is disclosed in claim 5, is characterized in that: in the RH vacuum circulation degassing process, the flow rate of bottom blowing gas in soft blowing is controlled at 40-80 NL/min.
8. The method for producing the steel for the battery pack support frame of the new energy electric automobile according to claim 3, which is characterized in that: in the step 5), the special premelted refining slag consists of the following components in percentage content: 45-50% of W (CaO) and 45-50% of W (SiO) 2 ) 20~25%、W(MgO) 5~6%、W(Al 2 O 3 ) 15-20% of special premelted refining slag, wherein the adding amount of the special premelted refining slag is 0.4-0.6Kg/t; the adding amount of the pre-desulfurization slag is 0.5-1.5Kg/t.
9. The method for producing the steel for the battery pack support frame of the new energy electric automobile according to claim 3, which is characterized in that: in the step 6), when the VD vacuum refining treatment is carried out, the vacuum degree is less than or equal to 67pa, the time is 8-12 minutes, and the argon flow is controlled at 35-70 NL/min.
10. The method for producing the steel for the battery pack support frame of the new energy electric automobile according to claim 3, which is characterized in that: in the step 8), the KOCKS rolling reduction is 13-18%, the KOCKS temperature is 810-830 ℃, and the steel finishing temperature is 730-800 ℃.
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Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106917033A (en) * | 2017-03-27 | 2017-07-04 | 武钢集团昆明钢铁股份有限公司 | A kind of preparation method of high-quality 40Cr alloy structures vertical bar round steel |
| CN109136466A (en) * | 2018-09-30 | 2019-01-04 | 武汉钢铁有限公司 | The method for making steel of sulfur-bearing Aluminum steel |
| CN109252008A (en) * | 2018-10-10 | 2019-01-22 | 新疆八钢铁股份有限公司 | A kind of production method of low carbon, low nitrogen ultralow-sulfur steel |
| CN110373600A (en) * | 2019-07-26 | 2019-10-25 | 石钢京诚装备技术有限公司 | A kind of high alumina sulfur-bearing control calcium steel smelting process |
| CN111235341A (en) * | 2020-03-23 | 2020-06-05 | 江苏利淮钢铁有限公司 | Production method of high-cleanliness sulfur-containing and aluminum-containing steel |
| CN111254358A (en) * | 2020-03-23 | 2020-06-09 | 江苏利淮钢铁有限公司 | Production method of steel for track link of ultrahigh-purity crawler belt |
| CN111254254A (en) * | 2020-03-10 | 2020-06-09 | 南京钢铁股份有限公司 | Preparation method of steel for sulfur-containing engineering machinery |
| CN113265583A (en) * | 2021-02-08 | 2021-08-17 | 江苏联峰能源装备有限公司 | Microalloy free-cutting non-adjusting steel for automobile crankshaft and production process thereof |
| CN114941111A (en) * | 2022-06-22 | 2022-08-26 | 江苏沙钢集团淮钢特钢股份有限公司 | Low-carbon non-quenched and tempered steel for automobile control arm and preparation method thereof |
| CN115011877A (en) * | 2022-06-10 | 2022-09-06 | 江苏联峰能源装备有限公司 | Non-quenched and tempered steel for sulfur-containing automobile crankshaft and production process thereof |
-
2023
- 2023-11-10 CN CN202311496141.2A patent/CN117230377B/en active Active
Patent Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106917033A (en) * | 2017-03-27 | 2017-07-04 | 武钢集团昆明钢铁股份有限公司 | A kind of preparation method of high-quality 40Cr alloy structures vertical bar round steel |
| CN109136466A (en) * | 2018-09-30 | 2019-01-04 | 武汉钢铁有限公司 | The method for making steel of sulfur-bearing Aluminum steel |
| CN109252008A (en) * | 2018-10-10 | 2019-01-22 | 新疆八钢铁股份有限公司 | A kind of production method of low carbon, low nitrogen ultralow-sulfur steel |
| CN110373600A (en) * | 2019-07-26 | 2019-10-25 | 石钢京诚装备技术有限公司 | A kind of high alumina sulfur-bearing control calcium steel smelting process |
| CN111254254A (en) * | 2020-03-10 | 2020-06-09 | 南京钢铁股份有限公司 | Preparation method of steel for sulfur-containing engineering machinery |
| CN111235341A (en) * | 2020-03-23 | 2020-06-05 | 江苏利淮钢铁有限公司 | Production method of high-cleanliness sulfur-containing and aluminum-containing steel |
| CN111254358A (en) * | 2020-03-23 | 2020-06-09 | 江苏利淮钢铁有限公司 | Production method of steel for track link of ultrahigh-purity crawler belt |
| CN113265583A (en) * | 2021-02-08 | 2021-08-17 | 江苏联峰能源装备有限公司 | Microalloy free-cutting non-adjusting steel for automobile crankshaft and production process thereof |
| CN115011877A (en) * | 2022-06-10 | 2022-09-06 | 江苏联峰能源装备有限公司 | Non-quenched and tempered steel for sulfur-containing automobile crankshaft and production process thereof |
| CN114941111A (en) * | 2022-06-22 | 2022-08-26 | 江苏沙钢集团淮钢特钢股份有限公司 | Low-carbon non-quenched and tempered steel for automobile control arm and preparation method thereof |
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