CN112708830B - Economical 620MPa lightweight automobile tank body end socket steel and production method thereof - Google Patents
Economical 620MPa lightweight automobile tank body end socket steel and production method thereof Download PDFInfo
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- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
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Abstract
The invention discloses an economical 620MPa lightweight automobile tank body end socket steel which is prepared from the following components in percentage by weight: c: 0.12-0.20%, Mn: 0.60-1.20%, Si: 0.05-0.20%, P: less than or equal to 0.015 percent, S: less than or equal to 0.010 percent, Nb: 0.010-0.040%, Al: 0.015 to 0.050%, Ti: 0.035-0.065%, B: 0.0005-0.0020%, N: not more than 0.0060 percent, and the balance of Fe and inevitable impurities. Simultaneously, the production method of the automobile tank body end socket steel is disclosed, and comprises the following steps: molten iron pretreatment, converter smelting, LF refining, slab continuous casting, rolling by a 1780mm rolling mill, and front-section sparse type dispersive cooling. The economic 620MPa lightweight automobile tank head steel strip with the thickness of 2.0-8.0mm prepared by the invention has the characteristics of yield strength distribution of 500MPa-620MPa, tensile strength distribution of 620MPa-720MPa, elongation A of 24-30%, and qualified 180-degree cold bending D of 1.0a, and has the characteristics of low production cost, good plasticity, excellent welding performance, low stamping cracking rate and the like.
Description
Technical Field
The invention relates to the technical field of steel materials, in particular to economical lightweight automobile tank end socket steel with the tensile strength of 620MPa and a production method thereof.
Background
The light weight of the automobile is an important way for energy conservation and emission reduction, and for the tank truck, the tank body has a large proportion of dead weight to the total weight, and the reduction of the weight of the tank body becomes the focus of attention of enterprises. The tank body is widely applied in daily life, and the seal head structures used on the front end face and the rear end face of the tank body have irreplaceable functions. At present, the production is realized by adopting a stamping method. The end socket manufactured by stamping requires harmonious and uniform appearance, uniform and consistent plastic deformation of the convex part and beautiful and smooth transition of the periphery of the end socket. The tank body end enclosure has higher requirements on forming quality relative to other parts of the cylinder body, and the main manufacturing procedures of the tank body end enclosure comprise cutting a semicircle, gas shield welding and stamping expansion. At present, most of materials used in the market are aluminum seal heads, stainless steel seal heads and steel seal heads, wherein the aluminum seal heads and the stainless steel seal heads are generally used for special tank bodies, such as oil pipes, corrosive media and the like, but the cost is relatively high, and the maintenance is difficult. However, the steel end socket has good comprehensive properties of low cost, easy processing, simple maintenance, easy recovery and treatment and the like. The existing 4.0-8.0 mm Q235B and Q355B materials seal heads in the market are heavy, and the problems of seal head welding seam stamping cracking, edge stretching opening cracking, mismatch with high-strength tank welding and the like frequently occur, so in order to improve or solve the problems and realize the light weight of the seal heads of steel powder tank cars and mechanical stirring tank cars, the economic seal head steel with the tensile strength of 620MPa is developed by means of components, smelting process, rolling process design and the like, the product can reduce the dead weight of the seal heads to realize the light weight of 10-15 percent, and the product has good forming performance.
Disclosure of Invention
The invention provides an economical 620MPa lightweight automobile tank body end socket steel, the special end socket steel product has the characteristics of low production cost, good plasticity, excellent welding performance, low stamping cracking rate and the like, can effectively solve the problems of weld heat affected zone and edge stretching cracking, realizes the lightweight end socket of steel powder tank cars and mechanical stirring tank cars, and saves social resources.
The invention also aims to provide a production method of the seal head steel of the powder tanker and the mechanical stirring tanker, which changes the internal structure of the steel by redesigning the components of the steel according to the structure-determined performance principle, thereby obtaining the steel with low cost, high strength, high plasticity and excellent weld heat affected zone performance.
In order to achieve the purpose, the invention adopts the technical scheme that:
an economical 620MPa lightweight automobile tank body end socket steel is prepared from the following components in percentage by weight: c: 0.12-0.20%, Mn: 0.60-1.20%, Si: 0.05-0.20%, P: less than or equal to 0.015 percent, S: less than or equal to 0.010 percent, Nb: 0.010-0.040%, Al: 0.015 to 0.050%, Ti: 0.035-0.065%, B: 0.0005-0.0020%, N: not more than 0.0060 percent, and the balance of Fe and inevitable impurities.
Wherein, C: carbon is an important element for improving the strength of steel, and as the carbon content increases, the strength of steel increases, and the pearlite content in steel may also be increased to offset the loss due to dislocation strengthening and solid solution strengthening after welding. When the carbon equivalent is less than 0.34% and the C content is less than 0.22%, the material has good welding performance, so that the selection of the carbon content needs to comprehensively consider the strength, toughness and plasticity of the steel, and the C content is controlled to be less than 0.20%.
Mn: manganese has the solid solution strengthening effect, can also reduce the gamma-alpha phase transition temperature, refine the structure and have great effect on improving the strength of steel; manganese can also improve the hardenability of steel; meanwhile, too high manganese can reduce welding performance and aggravate center segregation; in order to reduce the segregation of the manganese element, the content of the manganese element in the steel is not more than 1.50 wt%.
Si: solid solution strengthening, an increase in silicon content, increases the hardness and strength of the steel, but decreases plasticity and toughness. Meanwhile, when the silicon content exceeds 0.25%, the phenomenon of incomplete scale removal of primary oxide scales is easy to occur, and the welding performance of steel is also reduced due to the increase of the silicon content, so that the silicon content is controlled below 0.20% by comprehensively considering the method.
Nb: niobium can delay austenite recrystallization, reduce the phase transition temperature, improve the strength through mechanisms such as solid solution strengthening, phase transition strengthening, precipitation strengthening and the like, and the fine grain effect is favorable for improving the toughness of steel.
Ti: precipitation strengthening is a very effective important strengthening mode, the strength increment of hundreds of MPa can be obtained by adding a proper amount of titanium microalloy for strengthening, the titanium microalloy can be combined with N, the aging effect caused by N element is reduced, the influence of boron nitride grain boundary segregation generated by adding B element in steel grade to weaken the grain boundary is reduced, and meanwhile, the microalloy titanium carbonitride precipitated phase also has the functions of grain refinement and grain coarsening prevention in a welding heat affected zone. Therefore, in the scheme, multiple factors are comprehensively considered, the titanium content is controlled within a certain range, namely the solidification of N is ensured, and the full play of the effects of boron and titanium elements is also ensured.
B: boron can inhibit the transformation of polygonal ferrite but not inhibit B transformation, and the dissolution of trace B into austenite can increase the transformation incubation period of ferrite to tens of seconds. The bainite transformation curve is also flattened, so that the bainite structure is obtained even in the case of low carbon within a wide cooling range. Boron has the effect that the hardenability of the steel can be increased by times when a small amount (0.001-0.005%) of boron is contained in the steel. However, because the steel in B has high activity and is easy to form oxides or nitrides so as to reduce the effective B content in austenite, the steel added with B must be deoxidized by aluminum or treated by titanium, and therefore, the scheme comprehensively considers the matching of various properties.
Further, the economical 620MPa lightweight automobile tank body end socket steel is prepared from the following components in percentage by weight: c: 0.15 to 0.19%, Mn: 0.95-1.15%, Si: 0.08-0.18%, P: less than or equal to 0.015 percent, S: less than or equal to 0.005 percent, Nb: 0.015 to 0.025%, Al: 0.015 to 0.040%, Ti: 0.040-0.055%, B: 0.0009-0.0015%, N: less than or equal to 0.006 percent, and the balance of Fe and inevitable impurities.
The production method of the economical 620MPa lightweight automobile tank body end socket steel comprises the following steps: molten iron pretreatment, converter smelting, LF refining, slab continuous casting, rolling by a 1780mm rolling mill, front-section sparse type dispersed cooling, wherein,
the molten iron pretreatment is to ensure that the molten iron temperature is more than or equal to 1320 ℃, the molten iron desulfurization end point S is less than or equal to 0.002 percent, the molten iron desulfurization and slagging are clean, and the slagging bright surface is more than or equal to 95 percent in order to ensure the control of lower sulfur content of the molten iron;
the converter smelting adopts a medium carbon steel bottom blowing mode, slag making materials such as pig iron blocks, sludge balls and the like with the sulfur content of less than or equal to 0.05 percent are added, the furnace slag in the middle and later periods is controlled to be dried again, and the alkalinity of the final slag of the converter is more than or equal to 3.0;
during converter smelting, the key components at the end point are controlled as follows: 0.09-0.14 percent, less than or equal to 0.013 percent of P, less than or equal to 0.022 percent of S, 1670 percent of end point temperature, beginning and ending converter tapping, and stopping converter slag from falling into a steel ladle by adopting a sliding plate;
in the LF refining, in order to reduce the nitrogen increasing amount of molten steel and control the cleanliness of the molten steel in the LF refining process, the rotating speed of a dust removal fan needs to be adjusted in the LF heating process, so that the pressure in a smoke hood is ensured to be at micro positive pressure in the LF refining heating process, and external air is prevented from entering the smoke hood and contacting the molten steel; the liquid level of the steel can not be exposed in the smelting process, the flow of the bottom argon blowing single brick can not exceed 300NL/min during power transmission, and the submerged arc effect is ensured;
the LF refining is to ensure that the S content in molten steel is less than or equal to 0.005% by ensuring LF dislocation, white slag is manufactured and submerged arc heating is carried out, the use amount of fluorite (not more than 60kg) is not needed or reduced as much as possible, the white slag holding time is not less than 20min, centralized desulfurization is carried out after the slag manufacturing is finished, the large-flow stirring desulfurization time is shortened, and ferrocolumbium is added in the later stage of refining after the desulfurization task is finished; calcium treatment is carried out after LF refining treatment is finished, 200-300m of high calcium wire is fed in the calcium treatment process, the wire feeding speed is controlled to be 3-3.5 m/s in the calcium treatment process, and molten steel is blown for 6-9 min after the calcium treatment is finished;
the slab continuous casting is carried out, argon gas is adopted for protection in the whole process of a tundish in the casting process of a casting machine, slag discharging detection equipment is started in the process of pouring the ladle, and the ladle slag is prevented from flowing into the tundish when the pouring of the ladle is finished; the casting process of the casting machine is controlled by adopting a constant drawing speed, the drawing speed setting range is 0.90m/min-1.30m/min according to different casting sections, and the superheat degree of tundish casting is controlled at 15-25 ℃;
in order to avoid surface cracks and hot charging cracks of the casting blank, the slab needs to be cooled for more than 32 hours and passes low-power inspection;
the 1780mm rolling mill is used for rolling, wherein the rolling comprises rough rolling and finish rolling, the rough rolling adopts a 2-stand rolling mill for rough rolling, the finish rolling adopts a 7-stand continuous variable crown rolling mill for finish rolling, the furnace temperature of a heating furnace is 1200-; the rolling start temperature of the finish rolling is 1040-;
after the rolling of the 1780mm rolling mill is finished, a front-section sparse type dispersed cooling mode is adopted, the coiling temperature is 620-660 ℃, laminar flow continuous cooling equipment is adopted for cooling, specifications of cooling codes are set to be 12 and 28, 2.0-5.0mm, codes 12 (4 in each group) are adopted as upper-section cooling nozzles, one is turned off, two is turned off, one is turned on, the other is turned off, the upper-lower water ratio of 1-7 groups is 1.47, the upper-lower water ratio of 8-17 groups is 1.24, and 18-19 is turned off; 5.0-8.0mm, code 28 (5 in each group) is adopted to turn on/off one/two/one for the upper section cooling nozzle, the water-feeding and water-discharging ratio of 1-13 groups is 1.53, the water-feeding and water-discharging ratio of 14-17 groups is 1.33, and 18-19 are closed.
Compared with the prior art, the invention has the beneficial technical effects that:
1. the microstructure of the steel strip prepared by the invention has the characteristics of ferrite, pearlite and nano-scale titanium carbide precipitated phase, and the mechanical property is as follows: the high-strength high-elongation tank has high tensile strength and high elongation, has good weldability, formability and fatigue performance, can effectively and economically solve the problem of tensile cracking of a weld heat affected zone and an edge, realizes the light weight of tank body end sockets of a powder tank truck, a mechanical stirring tank truck and the like, and saves social resources.
2. The yield strength of the economical 620MPa lightweight automobile tank head steel strip with the thickness of 2.0-8.0mm prepared by the invention is distributed between 500MPa and 620MPa, the tensile strength is distributed between 620MPa and 720MPa, the elongation A is between 24% and 30%, and the steel strip is qualified when the steel strip is subjected to 180-degree cold bending D which is 1.0 a.
3. The special steel product for the seal head has the characteristics of low production cost, good plasticity, excellent welding performance, low stamping cracking rate and the like, can effectively solve the problem of tensile cracking of a weld heat affected zone and an edge, realizes the light seal head weight of a steel powder tank car and a mechanical stirring tank car, and saves social resources.
4. According to the production method of the tank car end socket steel, the internal organization structure of the steel is changed by redesigning the components of the steel according to the principle that the structure determines the performance, so that the tank car end socket steel with low cost, high strength, high plasticity and excellent weld heat affected zone performance is obtained.
Drawings
Fig. 1 is a metallographic structure diagram of the automotive tank head steel produced in example 1 of the present invention.
Detailed Description
The technical solutions and effects of the present invention will be further described with reference to the drawings and specific embodiments, but the scope of the present invention is not limited thereto.
Example 1
The production method of the automobile tank body end socket steel comprises the following steps: carrying out desulfurization pretreatment on molten iron, wherein the S content of the desulfurized KR molten iron leaving the station is 0.002%, and the temperature T of the molten iron is 1326 ℃; smelting by adopting a top-bottom combined blown converter to decarbonize and dephosphorize molten iron to obtain molten steel, blowing argon in the whole smelting process of the converter, wherein the tapping temperature of the converter is 1653 ℃, the carbon content of the tapped steel is 0.10%, carrying out deoxidation alloying treatment in the tapping process, and stopping slagging by adopting a sliding plate to block slag and tapping operation before and after tapping; then, carrying out LF external refining on the molten steel smelted by the converter, wherein the refining in-place temperature is 1549 ℃, and carrying out LF refining, slagging, deoxidizing and desulfurizing, and adjusting the component temperature; the casting superheat degree of a casting machine is 22 ℃; then slab slow cooling is carried out for 49 hours, and the quality of the continuous casting billet is checked; heating the plate blank at 1243 ℃, heating for 156min, discharging at 1239 ℃, and removing phosphorus from the heated plate blank by high-pressure water; rough rolling by adopting a 2-frame (the rough rolling adopts a 3+5 mode), wherein the thickness of an intermediate billet is 38mm, and finish rolling by adopting a 7-frame; the initial rolling temperature of finish rolling is 1061 ℃, and the finish rolling temperature of finish rolling is 880 ℃; the laminar cooling adopts a front-section sparse cooling mode 12 codes, and the coiling temperature is 653 ℃.
The steel strip produced according to the steps of this example had the following metallurgical composition: c: 0.16%, Si: 0.11%, Mn: 0.99%, P: 0.012%, S: 0.003%, Al: 0.036%, Nb: 0.018%, Ti: 0.042%, B: 0.0011%, N: 0.0051%.
The metallographic structure of the end socket steel for automobile tanks produced in this example is shown in fig. 1, and the metallographic structure mainly comprises 15-25% of pearlite and polygonal ferrite.
The performance indexes of the automobile tank head steel produced by the production method of the embodiment are shown in table 1.
TABLE 1 Performance index of the seal head steel of the automobile tank produced by the production method of the embodiment
Example 2
The production method of the automobile tank body end socket steel comprises the following steps: carrying out desulfurization pretreatment on molten iron, wherein the S content of the molten iron leaving a desulfurization KR station is 0.001%, and the temperature T of the molten iron is 1329 ℃; smelting by adopting a top-bottom combined blown converter to decarbonize and dephosphorize molten iron to obtain molten steel, blowing argon in the whole smelting process of the converter, wherein the tapping temperature of the converter is 1656 ℃, the carbon content of the tapped steel is 0.11%, carrying out deoxidation alloying treatment in the tapping process, and stopping slagging by adopting a sliding plate to block slag and tapping operation before and after tapping; then, carrying out LF external refining on the molten steel smelted by the converter, wherein the refining in-place temperature is 1543 ℃, and carrying out LF refining, slagging, deoxidizing and desulfurizing, and adjusting the component temperature; the degree of superheat of casting by a casting machine is 21 ℃; then slab slow cooling is carried out for 37 hours, and the quality of the continuous casting slab is checked; heating the plate blank at 1255 deg.C for 158min, discharging at 1243 deg.C, and removing phosphorus from the heated plate blank with high pressure water; rough rolling by adopting a 2-frame (the rough rolling adopts a 3+5 mode), wherein the thickness of an intermediate billet is 40mm, and finish rolling by adopting a 7-frame; the initial rolling temperature of finish rolling is 1055 ℃, and the finish rolling temperature of finish rolling is 870 ℃; the laminar cooling adopts a front-section sparse cooling mode 12 codes, and the coiling temperature is 645 ℃.
The steel strip produced according to the steps of this example had the following metallurgical composition: c: 0.17%, Si: 0.12%, Mn: 1.03%, P: 0.011%, S: 0.002%, Al: 0.034%, Nb: 0.017%, Ti: 0.044%, B: 0.0012%, N: 0.0049 percent.
The performance indexes of the automobile tank head steel produced by the production method of the embodiment are shown in table 2.
Table 2 performance indexes of the seal head steel for the car tank produced by the production method of this embodiment
Example 3
The production method of the automobile tank body end socket steel comprises the following steps: carrying out desulfurization pretreatment on molten iron, wherein the S content of desulfurized KR molten iron leaving a station is 0.002%, and the temperature T of the molten iron is 1329 ℃; smelting by adopting a top-bottom combined blown converter to decarbonize and dephosphorize molten iron to obtain molten steel, blowing argon in the whole smelting process of the converter, wherein the tapping temperature of the converter is 1656 ℃, the carbon content of the tapped steel is 0.12%, carrying out deoxidation alloying treatment in the tapping process, and stopping slagging by adopting a sliding plate to block slag and tapping operation before and after tapping; then, carrying out LF external refining on the molten steel smelted by the converter, wherein the refining in-place temperature is 1551 ℃, carrying out LF refining, slagging, deoxidizing and desulfurizing, and adjusting the component temperature; the degree of superheat of casting by a casting machine is 23 ℃; then slab slow cooling is carried out for 39 hours, and the quality of the continuous casting slab is checked; heating the plate blank at 1251 deg.C for 149min, discharging at 1243 deg.C, and removing phosphorus from the heated plate blank with high pressure water; rough rolling by adopting a 2-frame (the rough rolling adopts a 3+5 mode), wherein the thickness of an intermediate billet is 42mm, and finish rolling by adopting a 7-frame; the start rolling temperature of finish rolling is 1047 ℃, and the finish rolling temperature of finish rolling is 865 ℃; the laminar cooling adopts 28 codes of a front-section sparse cooling mode, and the coiling temperature is 636 ℃.
The steel strip produced according to the steps of this example had the following metallurgical composition: c: 0.17%, Si: 0.13%, Mn: 1.07%, P: 0.012%, S: 0.002%, Al: 0.0356%, Nb: 0.0198%, Ti: 0.047%, B: 0.0010%, N: 0.0053%.
The performance indexes of the automobile tank head steel produced by the production method of the embodiment are shown in table 3.
TABLE 3 Performance index of the seal head steel for automobile tank produced by the production method of this example
Example 4
The production method of the automobile tank body end socket steel comprises the following steps: carrying out desulfurization pretreatment on molten iron, wherein the S content of the desulfurized KR molten iron leaving the station is 0.001%, and the temperature T of the molten iron is 1331 ℃; smelting by adopting a top-bottom combined blown converter to decarbonize and dephosphorize molten iron to obtain molten steel, blowing argon in the whole smelting process of the converter, wherein the tapping temperature of the converter is 1654 ℃, the carbon content of the tapped steel is 0.11%, carrying out deoxidation alloying treatment in the tapping process, and stopping slagging by adopting a sliding plate to block slag and tapping operation before and after tapping; then, carrying out LF external refining on the molten steel smelted by the converter, wherein the refining in-place temperature is 1552 ℃, and carrying out LF refining, slagging, deoxidation and desulfurization, and adjusting the component temperature; the casting superheat degree of a casting machine is 19 ℃; then slab slow cooling is carried out for 61 hours, and the quality of the continuous casting billet is checked. Heating the plate blank at 1260 ℃, heating for 167min, discharging at 1255 ℃, and removing phosphorus from the heated plate blank by high-pressure water; rough rolling by adopting a 2-frame (the rough rolling adopts a 3+5 mode), wherein the thickness of an intermediate billet is 42mm, and finish rolling by adopting a 7-frame; the start rolling temperature of finish rolling is 1045 ℃, and the finish rolling temperature of finish rolling is 850 ℃; the laminar cooling adopts 28 codes of a front-section sparse cooling mode, and the coiling temperature is 625 ℃.
The steel strip produced according to the steps of this example had the following metallurgical composition: c: 0.18%, Si: 0.10%, Mn: 1.13%, P: 0.013%, S: 0.003%, Al: 0.035%, Nb: 0.022%, Ti: 0.051%, B: 0.0012%, N: 0.0047 percent.
The performance indexes of the automobile tank head steel produced by the production method of the embodiment are shown in table 4.
TABLE 4 Performance index of the seal head steel for automobile tank produced by the production method of this example
The economical 620 MPa-level automobile tank body end socket steel produced in the embodiment has the thickness of 2.0-8.0mm, the yield strength of 500-620MPa, the tensile strength of 620-720MPa and the elongation A after fracture of more than 24%.
Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.
Claims (1)
1. The economical 620MPa lightweight automobile tank body end socket steel with the thickness of 3.0 mm-3.5 mm is characterized in that the automobile tank body end socket steel is prepared from the following components in percentage by weight: c: 0.16-0.17%, Mn: 0.99-1.03%, Si: 0.11-0.12%, P: 0.011-0.012%, S: 0.002-0.003%, Nb: 0.017-0.018%, Al: 0.034-0.036%, Ti: 0.042-0.044%, B: 0.0011-0.0012%, N: 0.0049-0.0051% and the balance of Fe and unavoidable impurities;
the production method comprises the following steps: molten iron pretreatment, converter smelting, LF refining, slab continuous casting, rolling by a 1780mm rolling mill, front-section sparse type dispersed cooling, wherein,
the molten iron is pretreated, the temperature of the molten iron is 1326-1329 ℃, the content of S at the molten iron desulfurization end point is 0.001-0.002%, the molten iron desulfurization and slagging are clean, and the slagging bright surface is ensured to be more than or equal to 95%;
the converter smelting is carried out, a top-bottom combined blown converter is adopted for smelting, molten iron is subjected to decarburization and dephosphorization to obtain molten steel, argon is blown in the whole converter smelting process, the converter tapping temperature is 1653-1656 ℃, the tapping carbon content is 0.10-0.11%, P is less than or equal to 0.013%, S is less than or equal to 0.022%, deoxidation alloying treatment is carried out in the tapping process, and a sliding plate is adopted for slag stopping and tapping operation before and after tapping, so that slag discharging is avoided;
the LF refining is to ensure that the S content in molten steel is less than or equal to 0.005 percent by virtue of LF dislocation, white slag is manufactured and submerged arc heating is carried out, the white slag holding time is not less than 20min, centralized desulfurization is carried out after the slag is manufactured, ferrocolumbium is added at the later stage of refining after the desulfurization task is finished, calcium treatment is carried out after the LF refining treatment is finished, a high calcium line is fed for 200-300m in the calcium treatment process, the wire feeding speed is controlled to be 3-3.5 m/S in the calcium treatment process, and the molten steel is soft blown for 6-9 min after the calcium treatment is finished;
the slab continuous casting is carried out, argon gas is adopted for protection in the whole process of a tundish in the casting process of a casting machine, slag discharging detection equipment is started in the process of pouring the ladle, and the ladle slag is prevented from flowing into the tundish when the pouring of the ladle is finished; the casting process of the casting machine is controlled by adopting a constant drawing speed, the drawing speed setting range is 0.90-1.30 m/min according to different casting sections, and the superheat degree of tundish casting is controlled at 21-22 ℃; slowly cooling the plate blank for 37-49 hours, and rolling after quality inspection of the continuous casting blank;
the 1780mm rolling mill is used for rolling, wherein the rolling comprises rough rolling and finish rolling, the rough rolling adopts a 2-frame rolling mill for rough rolling, a 3+5 mode is adopted for rough rolling, the finish rolling adopts a 7-frame continuous variable camber rolling mill for finish rolling, the furnace temperature of a heating furnace is 1243-1255 ℃, the heating time is 156-158 min, the tapping temperature is 1239-1243 ℃, and the heated plate blank is subjected to high-pressure water dephosphorization; the final rolling temperature of rough rolling is 1040-; the initial rolling temperature of finish rolling is 1055-1061 ℃, the finish rolling temperature is 870-880 ℃, and the finish rolling is carried out until the thickness is 3.0-3.5 mm;
after the 1780mm rolling mill finishes rolling, adopting a front-section sparse type dispersed cooling mode, wherein the coiling temperature is 645-653 ℃;
the front-section sparse type dispersive cooling mode adopts laminar flow continuous cooling equipment, 4 cooling nozzles in each group are closed one by one, opened two by one, the upper-lower water ratio of 1-7 groups is 1.47, the upper-lower water ratio of 8-17 groups is 1.24, and 18-19 are closed;
the automobile tank body end socket steel prepared by the production method has yield strength of 568-583 MPa, tensile strength of 647-686 MPa, elongation A after fracture of 27.5-28.5% and qualified 180-degree cold bending D of 1.0 a.
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