CN115558838A - Production method of ultra-deep drawing cold-rolled steel strip with low temper mill elongation rate control - Google Patents
Production method of ultra-deep drawing cold-rolled steel strip with low temper mill elongation rate control Download PDFInfo
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C33/00—Making ferrous alloys
- C22C33/04—Making ferrous alloys by melting
- C22C33/06—Making ferrous alloys by melting using master alloys
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/0006—Adding metallic additives
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- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
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- C21C7/064—Dephosphorising; Desulfurising
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- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/04—Removing impurities by adding a treating agent
- C21C7/068—Decarburising
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/10—Handling in a vacuum
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- C21—METALLURGY OF IRON
- 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
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/26—Methods of annealing
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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
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0205—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips of ferrous alloys
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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
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
- C21D8/0226—Hot rolling
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- 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
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
- C21D8/0236—Cold rolling
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- C21—METALLURGY OF IRON
- 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
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- 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
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/46—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for sheet metals
- C21D9/48—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for sheet metals deep-drawing sheets
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/001—Ferrous alloys, e.g. steel alloys containing N
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- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/004—Very low carbon steels, i.e. having a carbon content of less than 0,01%
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/14—Ferrous alloys, e.g. steel alloys containing titanium or zirconium
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
Abstract
The invention discloses a production method of an ultra-deep drawing cold-rolled steel strip controlled by elongation of a low temper mill, which comprises the following processes: a steel-making process; the hot rolling process comprises the following steps: the heating temperature of the plate blank is 1160-1240 ℃; the heating time is 150-300 min; the rough rolling mode adopts 3+5; the finish rolling temperature is more than or equal to 890 ℃, and the coiling temperature is 650-740 ℃; a cold rolling process: annealing process parameters: the outlet temperature of the heating and soaking section is 780-860 ℃, the outlet temperature of the slow cooling section is 620-700 ℃, the outlet temperature of the fast cooling section is less than or equal to 450 ℃, the temperature of the overaging section is less than or equal to 400 ℃, the outlet temperature of the final cooling section is less than or equal to 200 ℃, and the elongation of the temper mill is 0.3-0.7%. The invention realizes the yield strength of the finished product of 110-140 MPa, the tensile strength of 280-310 MPa and the elongation after fracture of 42.0-51.0 percent, and ensures that the lower yield ratio is less than or equal to 0.50.
Description
Technical Field
The invention relates to the field of material forming, in particular to a production method of an ultra-deep drawing cold-rolled steel strip with controlled elongation of a low temper mill. The prepared material is widely used for stamping automobile parts with complex forming, such as side wall outer plates, automobile door inner plates, back door inner plates and the like of automobiles.
Background
The steel for ultra-deep drawing belongs to ultra-low carbon IF steel, namely interstitial-free steel, has excellent deep drawing performance, and is widely applied to the automobile industry. In IF steel, because the contents of C and N are low, a certain amount of strong carbon-nitrogen compounds such as titanium (Ti), niobium (Nb) and the like are added to form elements, and interstitial atoms such as carbon, nitrogen and the like in ultra-low carbon steel are completely fixed into the carbon-nitrogen compounds, so that clean ferrite steel, namely the ultra-low carbon interstitial-free steel, is obtained.
The ultra-low carbon IF steel is a steel grade with high added value and good deep drawing performance, is widely used in the manufacturing industries of automobiles, household electrical appliances and the like, and has large market demand. The current automobile industry is continuously improved on the aspect of stamping dies, continuous high-speed stamping becomes the development trend of modern stamping products, higher requirements are provided for the stamping forming performance of plates, and the tests are provided for steel-clad ultra-deep stamping steel strip products.
In order to ensure that the produced steel strip has lower yield strength and good plasticity, elements C and N and harmful elements O and S are strictly controlled at lower levels, and meanwhile, a proper amount of Ti alloy elements (the calculation formula of the residual Ti is that the residual Ti is = Ti- (3.4N + 1.5S + 4C) are added into the ultra-low carbon steel for component design, the control range of the excess titanium is 0.01-0.03 percent in consideration of the yield of the titanium and the influence of component change, and the excess titanium is combined with interstitial atoms of carbon and nitrogen in the steel to generate carbon-nitrogen compounds, so that the steel strip has obvious non-timeliness and realizes performance stability; meanwhile, in order to ensure that the steel strip has certain tensile strength, the contents of P and Mn strengthening elements are strictly controlled. In the aspect of production process, the influence difference of different production process parameters on yield and tensile strength is explored, the hot rolling procedure adopts stronger cooling speed to refine the metallographic structure of the steel strip, so that fine grain strengthening is realized, and the steel strip obtains higher tensile strength; because the effect of the adjustment of the elongation of the temper mill on the yield strength is obviously larger than the influence on the tensile strength, the annealing process is matched with proper annealing temperature and low temper mill elongation, the yield strength of the steel strip is greatly reduced, the yield strength rise caused by fine grain strengthening is relieved, the influence on the tensile strength is small, the low yield ratio is realized, and the product deformability is improved. The production process mainly designs the core processes of components, hot rolling and cold rolling through smelting, a 2250mm rolling mill, acid continuous rolling and continuous annealing processes.
Disclosure of Invention
In order to solve the technical problems, the invention aims to provide a method for producing an ultra-deep drawing cold-rolled steel strip with low temper mill elongation control, wherein a hot rolling process adopts a quick cooling mode to refine crystal grains, the tensile strength of a product is improved through fine grain strengthening, a continuous annealing process is matched with proper annealing temperature and low temper mill elongation, the yield strength of a finished product is 110-140 MPa, the tensile strength is 280-310 MPa, the elongation after fracture is 42.0-51.0% (transverse direction, tensile test: L0=80mm, b = 20mm), the n value is 0.23-0.25, the r value is 2.4-3.5, the lower yield ratio is less than or equal to 0.50, and the high elongation after fracture and the r value are ensured, so that the ultra-deep drawing cold-rolled steel strip has excellent stamping forming performance.
In order to solve the technical problems, the invention adopts the following technical scheme:
the invention relates to a production method of an ultra-deep drawing cold-rolled steel strip controlled by elongation of a low temper mill, which comprises the following processes:
the steel-making process comprises the following steps: molten iron → converter steelmaking → RH refining → slab continuous casting; carrying out converter smelting after the molten iron is subjected to desulfurization pretreatment, wherein the sulfur content of the molten iron fed into the converter is required to be less than 0.004%, and the slag removing area of the molten iron is more than 95%; the tapping temperature of converter smelting is required to be more than or equal to 1660 ℃, a turnover ladle is required to be used for tapping, and the tapping temperature drop is required to be less than 70 ℃; the RH process requires deep decarburization treatment according to the in-place components and temperature of RH molten steel supplied by a converter, after decarburization is finished, aluminum particles are added for deoxidation according to the oxygen determination condition, and ferrotitanium is added for adjusting the components after circulation is carried out for more than 4 minutes; after the components are adjusted, the temperature can be measured and sampled when the vacuum circulation is not less than 5min, after the ferrotitanium is added, the pure degassing time is ensured to be more than 5min, and the superheat degree of the molten steel is 25-60 ℃;
the hot rolling process comprises the following steps: heating a plate blank → descaling with high pressure water → a constant width press → rolling of an E1R1 roughing mill → rolling of an E2R2 roughing mill → flying shear → descaling with high pressure water → rolling of an F1-F7 finishing mill → cooling with dense laminar flow → coiling → a pallet transportation system → sampling and inspection; the heating temperature of the plate blank is 1160-1240 ℃; the heating time is 150-300 min; the rough rolling mode adopts 3+5; the finish rolling temperature is more than or equal to 890 ℃, and the coiling temperature is 650-740 ℃;
the cold rolling process comprises the following steps: acid rolling and uncoiling → welding → straightening → acid washing → drying → trimming → tandem cold rolling → slitting → coiling → off-line inspection → weighing → marking → bundling → packaging → warehousing → continuous uncoiling → welding → cleaning → inlet loop → annealing furnace → outlet loop → leveling → inspection loop → trimming → surface inspection → oiling → coiling → weighing → sampling and inspection; annealing process parameters: the outlet temperature of the heating and soaking section is 780-860 ℃, the outlet temperature of the slow cooling section is 620-700 ℃, the outlet temperature of the fast cooling section is less than or equal to 450 ℃, the temperature of the overaging section is less than or equal to 400 ℃, the outlet temperature of the final cooling section is less than or equal to 200 ℃, and the elongation of the temper mill is 0.3-0.7%.
Further, the prepared steel strip comprises the following chemical components in percentage by mass: less than or equal to 0.0040 percent of C, less than or equal to 0.030 percent of Si, less than or equal to 0.30 percent of Mn, less than or equal to 0.020 percent of P, 0.050 to 0.080 percent of Ti, more than or equal to 0.020 percent of Al, less than or equal to 0.010 percent of S, less than or equal to 0.0040 percent of O, less than or equal to 0.0040 percent of N, and the balance of Fe and inevitable impurities.
Furthermore, the yield strength of the finished steel strip is 110-140 MPa, the tensile strength is 280-310 MPa, the elongation after fracture is 42.0-51.0%, the n value is 0.23-0.25, the r value is 2.4-3.5, the yield ratio is less than or equal to 0.50, the elongation after fracture and the r value are high, and the finished steel strip has excellent stamping forming performance.
Compared with the prior art, the invention has the beneficial technical effects that:
in the production method, the steel-making process adopts an RH refining process and a vacuum degassing technology, the contents of C and N elements are not higher than 0.0040 percent, and the steel is pure; ti alloy elements are adopted to fix C and N interstitial atoms to form interstitial-free steel, so that the interstitial-free steel has no timeliness and good performance stability; by searching the influence difference of different process parameters on performance indexes such as yield strength, tensile strength, elongation, r value and the like, the hot rolling adopts rapid cooling, crystal grains are refined, the tensile strength is improved, the continuous annealing process is matched with proper annealing temperature, and the stable control of the elongation of the low temper mill is realized; the ultra-deep drawing cold-rolled steel strip keeps low yield strength, improves the tensile strength of the steel strip, achieves low yield ratio, has high elongation after fracture and r value, and is more beneficial to stamping forming.
Drawings
The invention is further illustrated in the following description with reference to the drawings.
FIG. 1 shows the metallographic structure of the finished product.
Detailed Description
A production method of ultra-deep drawing cold-rolled steel strip with controlled elongation rate of a low temper mill comprises the following steps:
1. smelting process
1.1 desulfurization pretreatment: adopt KR molten iron desulfurization technique, the terminal point sulphur content is within 0.004% after requiring deep desulfurization, KR desulfurization is through mechanical stirring method desulfurization, the stirring head inserts the rotation in the molten iron, make the molten iron produce the swirl, then drop into the desulfurizer to the molten iron swirl, make the sulfur in desulfurizer and the molten iron take place desulfurization reaction in continuous stirring, completely take off the desulfurization sediment clean after the desulfurization is accomplished, it is greater than 95% to require the molten iron sediment to take off the clear area requirement, prevent that high sulfur sediment from mixing in the converter and leading to the resulfurization.
1.2 converter smelting: the molten iron is smelted in a converter after being subjected to desulfurization pretreatment, and the converter dephosphorization process mainly depends on slag with high alkalinity, high oxidizability and large slag amount for dephosphorization. However, if deep dephosphorization is required, conditions are created so that phosphorus in the molten iron can be greatly oxidized into slag, and the aim of deep dephosphorization can be achieved. The phosphorus content of the molten iron fed into the converter is less than or equal to 0.015 percent, oxygen blowing, decarburization and temperature rising are carried out, the P and S components are controlled, the molten steel is prevented from being oxidized excessively, the end point temperature of the converter is controlled to be more than 1660 ℃, a turnover ladle is required to be used for tapping, and the tapping temperature drop is required to be less than 70 ℃. And adding ferromanganese for alloying in the converter tapping process, and adding lime and a modifier for top slag modification.
1.3 refining: the RH refining furnace carries out decarburization treatment according to the in-place components and the temperature of molten steel, RH decarburization is the most important decarburization link in the production of ultra-low carbon steel, and all factors which are beneficial to improving the decarburization rate can accelerate the decarburization reaction due to the strong high temperature and stirring in the vacuum treatment. In the process of rapidly reducing the pressure in the vacuum chamber, along with the increase of the flow of the lifting gas, the circulation flow and the volume coefficient are increased, the decarburization rate is improved, the decarburization reaction is accelerated, after the decarburization is finished, a deoxidizer and the component aluminum are added according to the oxygen determination condition, and after the circulation is carried out for more than 5 minutes, the alloy such as ferrotitanium, ferroniobium, manganese metal, micro-carbon ferrosilicon, ferrophosphorus and the like is added to adjust the components. After the components are adjusted, temperature measurement and sampling can be carried out after vacuum circulation is carried out for 3min, and after ferrotitanium is added, pure degassing time is guaranteed to be more than 6min, so that homogenization of molten steel temperature components is guaranteed, floating of molten steel inclusions is facilitated, and cleanliness of molten steel is improved.
1.4 continuous casting: the continuous casting protects the pouring, prevents the secondary oxidation of the molten steel and avoids the secondary oxidation of the steel quality of the molten steel. The casting speed is controlled to be 1.0-2.0 m/min at constant casting speed, the proper superheat degree of the casting is controlled, the superheat degree is controlled to be about 25-60 ℃ in the casting process, the floating of inclusions is promoted, and multi-furnace casting is realized.
2 Hot Rolling Process
A step-by-step heating furnace is adopted to heat a casting blank (the heating process is shown in table 1), double-frame R1 and double-frame R2 are adopted to carry out reciprocating rolling in the rough rolling mode of 3+5, the continuous rolling process of F1-F7 is adopted in the finish rolling, the finish rolling temperature is 890-960 ℃, the austenite single-phase region rolling is ensured, the coiling temperature is 650-740 ℃, the normal precipitation of carbonitrides is ensured, and the deep drawing performance is improved, and the specific hot rolling process is shown in table 2.
TABLE 1 casting blank heating System
TABLE 2 Rolling Process
3 annealing process
The annealing adopts a vertical continuous annealing furnace, and the furnace is cooled by adopting a mixed protective atmosphere of reducing atmosphere and nitrogen and hydrogen. The temperature ranges of the heating section and the soaking section are 780-860 ℃, the complete recrystallization of crystal grains is ensured, the control condition of the temperature of the outlet of each section of the heating furnace is shown in table 3, and the control conditions of different thicknesses of the elongation of the temper mill are shown in table 4.
TABLE 3 annealing Process
TABLE 4 temper mill elongation
4 analysis of examples
4.1 steelmaking Components
According to the above steel making process requirements, the actual slab chemical composition (mass%) is shown in table 5 below.
Table 5 example chemical composition wt. -%)
4.2 Hot Rolling Properties
According to the above design chemical components and hot rolling process, the hot rolled plate has room temperature tensile properties shown in Table 6, and tensile test specimens
The test method is referred to GB/T228.1.
TABLE 6 Hot Rolling tensile Properties
4.3 Final Properties
And (3) cold rolling and annealing are carried out on the basis of the hot rolling performance, the room-temperature tensile mechanical property of the finished product is shown in Table 7, the metallographic structure is equiaxed ferrite, the grain size is 7.5-8.5 grade, and the structure and the appearance are shown in figure 1.
TABLE 7 tensile Properties of the finished product
In conclusion, the product meets the requirements through performance inspection and various performances of users, and is supplied in batches.
The above-described embodiments are only intended to illustrate the preferred embodiments of the present invention, and not to limit the scope of the present invention, and various modifications and improvements made to the technical solution of the present invention by those skilled in the art without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.
Claims (3)
1. A production method of ultra-deep drawing cold-rolled steel strip controlled by elongation rate of a low temper mill is characterized by comprising the following steps: the method comprises the following steps:
the steel-making process comprises the following steps: molten iron → converter steelmaking → RH refining → slab continuous casting; carrying out converter smelting after the molten iron is subjected to desulfurization pretreatment, wherein the sulfur content of the molten iron fed into the converter is required to be less than 0.004%, and the slag removing area of the molten iron is more than 95%; the tapping temperature required by converter smelting is more than or equal to 1660 ℃, a turnover ladle is required to be used for tapping, and the tapping temperature drop requirement is less than 70 ℃; the RH process requires deep decarburization treatment according to the in-place components and temperature of RH molten steel supplied by a converter, after the decarburization is finished, aluminum particles are added for deoxidation according to the oxygen determination condition, and ferrotitanium is added for adjusting the components after circulation is carried out for more than 4 minutes; after the components are adjusted, the temperature can be measured and sampled when the vacuum circulation is not less than 5min, after ferrotitanium is added, the pure degassing time is ensured to be more than 5min, and the superheat degree of molten steel is 25-60 ℃;
the hot rolling process comprises the following steps: heating a plate blank → descaling with high pressure water → a constant width press → rolling of an E1R1 roughing mill → rolling of an E2R2 roughing mill → flying shear → descaling with high pressure water → rolling of an F1-F7 finishing mill → cooling with dense laminar flow → coiling → a pallet transportation system → sampling and inspection; the heating temperature of the plate blank is 1160-1240 ℃; the heating time is 150-300 min; the rough rolling mode adopts 3+5; the finish rolling temperature is more than or equal to 890 ℃, and the coiling temperature is 650-740 ℃;
the cold rolling process comprises the following steps: acid rolling uncoiling → welding → straightening → acid washing → rinsing → drying → trimming → tandem rolling → splitting → coiling → off-line inspection → weighing → marking → bundling → packaging → warehousing → uncoiling → welding → cleaning → inlet loop → annealing furnace → outlet loop → flattening → inspection loop → trimming → surface inspection → oil coating → coiling → weighing → sampling and inspecting; annealing process parameters: the outlet temperature of the heating and soaking section is 780-860 ℃, the outlet temperature of the slow cooling section is 620-700 ℃, the outlet temperature of the fast cooling section is less than or equal to 450 ℃, the temperature of the overaging section is less than or equal to 400 ℃, the outlet temperature of the final cooling section is less than or equal to 200 ℃, and the elongation of the temper mill is 0.3-0.7%.
2. The method for producing ultra-deep drawn cold rolled steel strip with controlled elongation for low temper mill according to claim 1, wherein: the prepared steel strip comprises the following chemical components in percentage by mass: less than or equal to 0.0040 percent of C, less than or equal to 0.030 percent of Si, less than or equal to 0.30 percent of Mn, less than or equal to 0.020 percent of P, 0.050 to 0.080 percent of Ti, more than or equal to 0.020 percent of Al, less than or equal to 0.010 percent of S, less than or equal to 0.0040 percent of O, less than or equal to 0.0040 percent of N, and the balance of Fe and inevitable impurities.
3. The method of producing a low temper mill elongation controlled extra deep drawn cold rolled steel strip according to claim 1, wherein: the finished steel belt has yield strength of 110-140 MPa, tensile strength of 280-310 MPa, elongation after fracture of 42.0-51.0%, n value of 0.23-0.25, r value of 2.4-3.5, yield ratio of less than or equal to 0.50, high elongation after fracture and r value, and excellent stamping forming performance.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211139633.1A CN115558838A (en) | 2022-09-19 | 2022-09-19 | Production method of ultra-deep drawing cold-rolled steel strip with low temper mill elongation rate control |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211139633.1A CN115558838A (en) | 2022-09-19 | 2022-09-19 | Production method of ultra-deep drawing cold-rolled steel strip with low temper mill elongation rate control |
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| US4397699A (en) * | 1980-05-27 | 1983-08-09 | Nippon Steel Corporation | Process for producing deep-drawing cold rolled steel strip by continuous annealing |
| CN110438312A (en) * | 2019-08-02 | 2019-11-12 | 包头钢铁（集团）有限责任公司 | A method of improving cold-rolling deep-punching steel elongation and strain hardening exponent n value |
| CN110791705A (en) * | 2019-10-21 | 2020-02-14 | 包头钢铁（集团）有限责任公司 | 340 MPa-grade Ti-P series phosphorus-added high-strength IF steel belt for automobile and manufacturing method thereof |
| CN113462960A (en) * | 2021-06-01 | 2021-10-01 | 包头钢铁（集团）有限责任公司 | Preparation method of 340 MPa-grade niobium-containing hot-galvanized high-strength IF steel |
| CN114525449A (en) * | 2022-01-28 | 2022-05-24 | 包头钢铁（集团）有限责任公司 | DC04 automobile steel plate for cold rolling deep drawing and manufacturing method thereof |
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- 2022-09-19 CN CN202211139633.1A patent/CN115558838A/en active Pending
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| Publication number | Priority date | Publication date | Assignee | Title |
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| US4397699A (en) * | 1980-05-27 | 1983-08-09 | Nippon Steel Corporation | Process for producing deep-drawing cold rolled steel strip by continuous annealing |
| CN110438312A (en) * | 2019-08-02 | 2019-11-12 | 包头钢铁（集团）有限责任公司 | A method of improving cold-rolling deep-punching steel elongation and strain hardening exponent n value |
| CN110791705A (en) * | 2019-10-21 | 2020-02-14 | 包头钢铁（集团）有限责任公司 | 340 MPa-grade Ti-P series phosphorus-added high-strength IF steel belt for automobile and manufacturing method thereof |
| CN113462960A (en) * | 2021-06-01 | 2021-10-01 | 包头钢铁（集团）有限责任公司 | Preparation method of 340 MPa-grade niobium-containing hot-galvanized high-strength IF steel |
| CN114525449A (en) * | 2022-01-28 | 2022-05-24 | 包头钢铁（集团）有限责任公司 | DC04 automobile steel plate for cold rolling deep drawing and manufacturing method thereof |
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