CN113528948A - Steel for high-plasticity-toughness automobile structural part with tensile strength of 2000MPa produced by CSP and production method - Google Patents
Steel for high-plasticity-toughness automobile structural part with tensile strength of 2000MPa produced by CSP and production method 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
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
- B21C37/00—Manufacture of metal sheets, bars, wire, tubes or like semi-manufactured products, not otherwise provided for; Manufacture of tubes of special shape
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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
- C21D8/005—Modifying the physical properties by deformation combined with, or followed by, heat treatment of ferrous alloys
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- 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
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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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- 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
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/48—Ferrous alloys, e.g. steel alloys containing chromium with nickel with niobium or tantalum
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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
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/001—Austenite
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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
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/002—Bainite
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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
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/008—Martensite
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Abstract
A steel for producing a high-plasticity and toughness automobile structural part with the tensile strength of 2000MPa by using CSP comprises the following chemical components in percentage by weight: c: 0.33 to 0.40%, Si: 1.66-2.05%, Mn: 2.00-2.80%, P: 0.010% or less, S: 0.005% or less, Als: 0.010-0.050%, Cr: 0.56-0.70%, Nb 0.056-0.065%, Ni: 0.20-0.30%, N: less than 0.004%; the process comprises the following steps: desulfurizing molten iron; smelting and refining in an electric furnace or a converter; continuous casting; descaling for the first time; soaking; descaling for the second time; rolling; laminar cooling; coiling; uncoiling and blanking or pickling and then blanking into blanks; heating the blank; punching and forming; and cleaning, trimming and cutting the surface of the part. The invention not only has the yield strength of more than or equal to 1080MPa, the tensile strength of more than or equal to 1855MPa and the elongation of more than or equal to 8.6 percent, but also ensures that the product of strength and elongation is 17.8-20.4 GPa, and completely meets the requirements of lightweight structural parts of luxurious electric automobiles on the strength and the collision energy absorption characteristics of 2000 MPa-level high-collision-resistance parts.
Description
Technical Field
The invention relates to an automobile steel and a production method thereof, in particular to a high-ductility and toughness automobile structural member steel with the tensile strength of 2000MPa and a production method thereof, which are more suitable for requirements of luxury electric automobile structural members.
Background
With the development of the automobile industry, the continuous gliding phenomenon appears in the automobile market in China. For example, in 2020, the output and sales of Chinese automobiles are 2522.5 ten thousand and 2531.1 ten thousand respectively, and the output and sales are reduced by 2.0 percent and 1.9 percent respectively in the same ratio. Under the background of saturated production and sale in the automobile market, the improvement of automobile quality and the upgrading of industry are imminent, and the automobile manufacturing gradually develops towards the directions of light weight, intellectualization and networking, so that higher requirements are provided for the ultrahigh-strength material for the light-weight automobile body.
At present, the research surge of developing materials for ultrahigh-strength structural members for automobiles is raised worldwide, and the materials are mainly divided into two types: one type is an ultra-high strength automobile structural member formed by cold stamping, and the design of the product mainly adopts a high alloy content steel material, which adds a large amount of alloy elements into steel, improves the hardenability of the steel and simultaneously improves the room temperature stability of austenite, thereby ensuring that the developed steel has ultra-high strength and good forming performance. However, the alloy of the steel has high cost, complex process, difficult manufacturing process and low yield, and the problems of rebound, cracking, poor dimensional precision of parts and the like are easy to occur in the manufacturing process of the parts. The other type is that a proper heat treatment process mode is adopted in the part manufacturing process to realize high strengthening of the part, the alloy content of the steel for the part is lower than that of the ultrahigh-strength steel for the cold stamping forming part, and the ultrahigh-strength part is mainly obtained through the heat treatment process before or after forming. However, the steel produced by the prior art has poor strength and plasticity, the product of strength and plasticity for representing the forming capability of materials for high-strength parts for automobiles and the size of the deformation energy absorbed in the collision process is only about 5-10 GPa%, and the requirements of light weight of automobile bodies and high collision safety and energy absorption performance which are increasingly developed in the automobile industry cannot be met.
After retrieval:
chinese patent publication No. CN 101381839B discloses "a high-strength-ductility alloy steel and its heat treatment process". The high-strength-ductility alloy steel disclosed by the document comprises the following chemical components in percentage by weight: c: 0.03 to 0.05%, Mn: 30 ± 0.5%, Al: 3 ± 0.5%, Si: 3 plus or minus 0.5 percent and the balance of iron; the steel is heated to 1100 ℃ and is kept warm for 2-5 hours, and then the steel is quickly put into water for quenching. The tensile strength of the obtained workpiece is 650-700 MPa, the elongation after fracture is 55-70%, and the product of strength and elongation is 35-49 GPa. Although the product of strength and elongation of the steel is high, the alloy content is high, particularly the manganese content reaches 30%, and meanwhile, the steel needs long-time heat treatment, so that the industrial production difficulty is high, the alloy cost and the energy consumption are high, the strength is only 650-700 MPa, although the product of strength and elongation is high, the strength is low, and the requirements of lightweight automobile body design on structural parts with high impact resistance and high energy absorption performance cannot be met.
Chinese patent publication No. CN 107587052a discloses "a cold-rolled high-strength steel for automobile structural members and a manufacturing method thereof". The weight percentage of the main components is as follows: 0.06 to 0.08 percent of C, 0.65 to 0.95 percent of Mn, less than or equal to 0.05 percent of Si, less than or equal to 0.015 percent of P, less than or equal to 0.015 percent of S, 0.030 to 0.055 percent of Als, 0.025 to 0.040 percent of Nb and 0.010 to 0.030 percent of Ti. The high-strength steel plate obtained by hot rolling, acid pickling and cold continuous rolling, continuous annealing, flattening and straightening is 400MPa in yield strength of 330-. Although the method can produce an automobile structural part, the strength is low due to the unreasonable element content design, and the requirement of automobile light weight design on ultrahigh-strength parts cannot be met.
In short, although the prior art can manufacture the automobile structural member, the strength and the product of strength and elongation are low, and the requirements of lightweight automobile body design on the 2000 MPa-level structural member with high impact resistance and high energy absorption performance cannot be met. Although some workpieces with high product of strength and elongation can be obtained by adding a large amount of alloy and carrying out long-time heat treatment, the workpieces have low strength, high cost and difficult industrial mass production, and the requirements of lightweight design of automobiles on structural parts with high impact resistance and high energy absorption can not be met.
Disclosure of Invention
The invention aims to overcome the defects in the prior art, and provides the steel for the high-plasticity and toughness automobile structural part and the production method thereof, wherein the steel is designed by low alloy components and matched with a proper tissue regulation and control process, so that the steel can ensure that the yield strength is 1050-1350 MPa, the tensile strength is 1850-2150 MPa, the elongation is more than or equal to 8.5%, and the product of strength and elongation is more than or equal to 15 GPa%, thereby meeting the requirements of lightweight luxurious electric automobile structural parts on the strength and the collision energy absorption characteristics of 2000 MPa-grade high-collision-resistance parts.
The measures for realizing the aim are as follows:
a steel for producing a high-plasticity and toughness automobile structural part with the tensile strength of 2000MPa by using CSP comprises the following chemical components in percentage by weight: c: 0.33 to 0.40%, Si: 1.66-2.05%, Mn: 2.00-2.80%, P: 0.010% or less, S: 0.005% or less, Als: 0.010-0.050%, Cr: 0.56-0.70%, Nb 0.056-0.065%, Ni: 0.20-0.30%, N: less than 0.004%, and the balance of Fe and inevitable impurities; the metallographic structure is as follows: the volume content of martensite is 88-93%, the volume content of bainite is 2-5%, and the volume content of residual austenite is 5-7%.
Preferably: the weight percentage of the Si is 1.72-2.05%.
Preferably: the weight percentage of Mn is 2.36-2.80%.
Preferably: the weight percentage of the Cr is 0.61-0.70%.
Preferably: the weight percentage of Nb is 0.059-0.065%.
Preferably: the weight percentage of the Ni is 0.23-0.30%.
A production method for producing high-ductility and toughness steel for an automobile structural part with tensile strength of 2000MPa by using CSP comprises the following steps:
1) desulfurizing molten iron, and controlling S to be less than or equal to 0.001%;
2) smelting and refining in an electric furnace or a converter;
3) continuous casting is carried out, the superheat degree of the tundish molten steel is controlled to be 15-35 ℃, the thickness of a casting blank is 50-70 mm, and the blank drawing speed is 3.0-5.0 m/min;
4) carrying out primary descaling on the casting blank, and controlling the pressure of descaling water to be not lower than 190 bar;
5) soaking the casting blank, and controlling the discharging temperature of the casting blank to be 1230-1260 ℃;
6) carrying out secondary descaling on the casting blank, and controlling the pressure of descaling water to be not lower than 230 bar;
7) rolling: and controlling the thickness of a finish rolling outlet to be 0.80-4.0 mm; controlling the first and second pass reduction rates to be not less than 50%; controlling the finish rolling temperature to be 930-950 ℃;
8) laminar cooling to coiling temperature;
9) coiling, wherein the coiling temperature is controlled to be 690-720 ℃;
10) directly uncoiling and blanking or blanking after acid cleaning to obtain a blank of the structural part to be prepared;
11) heating the blank to 850-880 ℃ at the heating speed of 8-12 ℃/s, and preserving heat for 360-600 s at the temperature;
12) stamping forming: stamping the heated blank into an automobile structural member to be prepared, wherein the cooling speed is controlled to be 30-50 ℃/s, and the metallographic structure of the formed member at room temperature is controlled to be that the volume content of martensite is 88-93%, the volume content of bainite is 2-5%, and the volume content of retained austenite is 5-7%;
13) and cleaning, trimming and cutting the surface of the part.
Preferably: the blank is heated to 850-873 ℃ at the heating speed of 10-12 ℃/s, and the temperature is kept for 395-600 s at the temperature.
Preferably: and controlling the cooling speed to be 36-44 ℃/s in the punch forming.
The action and mechanism of each element and main process in the invention
C: carbon plays a key role in obtaining ultrahigh-strength and multiphase structures, the carbon content and the distribution of the carbon content in steel have great influence on the structure form, type and performance of a final product, but the content is too high, a large amount of bainite, martensite and other hard phases are easily formed in the cooling process after finish rolling, the content is higher, the strength is higher, and the plasticity is reduced. Therefore, the carbon content is not easy to be too high on the premise of ensuring the die quenching treatment strengthening. Therefore, the content is limited to 0.33 to 0.40%.
Si: silicon has a strong solid solution strengthening effect, can improve the strength of steel, can effectively inhibit the formation of carbides, plays a key role in the distribution and the state of carbon elements in the steel, and is one of important elements of the steel with ultrahigh strength and high plasticity; meanwhile, the hardness of the steel can be reduced slowly during tempering, and the tempering stability and strength of the steel are improved. Therefore, the content is limited to 1.66 to 2.05%, and the content of Si is preferably 1.72 to 2.05% by weight.
Mn: manganese has a solid solution strengthening effect, can reduce the phase transformation driving force, enables the C curve to move to the right, improves the hardenability of the steel, enlarges the gamma phase region, and can reduce the Ms point of the steel, so that martensite can be obtained at a proper cooling speed. Meanwhile, the Mn-Si-Mn alloy is matched with a certain silicon content and added into steel, can enhance the room temperature stability of austenite, and is an important element obtained by matching high strength and high plasticity, so the content of Mn is limited to be within the range of 2.00-2.80%, and the weight percentage of Mn is preferably 2.36-2.80%.
Cr: chromium can reduce the phase transformation driving force and the nucleation growth of carbide during phase transformation, thereby improving the hardenability of the steel. In addition, the chromium can improve the tempering stability and the high-temperature oxidation resistance of the steel. Therefore, the content is limited to 0.56-0.70%, and the content of Cr is preferably 0.61-0.70% by weight.
Ni: the addition of nickel to steel increases the strength of the steel without significantly reducing its toughness. And at the same time, the workability and weldability of the steel can be improved. In addition, nickel can improve the corrosion resistance of steel, and can resist acid, alkali and atmosphere corrosion. Therefore, the content is limited to 0.20-0.30%, and the weight percentage of Ni is preferably 0.23-0.30%.
Als, which plays a role in deoxidizing steel, should ensure that a certain amount of acid-soluble aluminum exists in the steel, otherwise the effect cannot be exerted, but too much aluminum can also cause aluminum series inclusions in the steel, and is not beneficial to smelting and casting of the steel. Meanwhile, the proper amount of aluminum is added into the steel, so that the adverse effect of nitrogen and oxygen atoms in the steel on the performance can be eliminated. Therefore, the content is limited to 0.010-0.050%.
P: phosphorus is a harmful element in steel and is easy to cause center segregation of a casting blank. The steel is easy to be deviated to a grain boundary in the subsequent hot continuous rolling heating process, so that the brittleness of the steel is obviously increased. Meanwhile, the content of the steel is controlled to be below 0.010 percent based on the consideration of cost and without influencing the performance of the steel.
S: sulfur is a very harmful element. Sulfur in steel often exists in the form of sulfide of manganese, and this sulfide inclusion deteriorates toughness of steel and causes anisotropy of properties, so that the lower the sulfur content in steel, the better. The sulfur content in steel is controlled to 0.005% or less in consideration of the manufacturing cost.
N: nitrogen can combine with titanium in the titanium-added steel to form titanium nitride, and the second phase precipitated at high temperature is beneficial to strengthening the matrix and improving the welding performance of the steel plate. However, the content of nitrogen is higher than 0.004%, the solubility product of nitrogen and titanium is higher, titanium nitride with coarse particles can be formed in the steel at high temperature, and the plasticity and the toughness of the steel are seriously damaged; in addition, higher nitrogen content increases the amount of micro-alloying elements needed to stabilize the nitrogen element, thereby increasing costs. Therefore, the content is controlled to be less than 0.004%.
Nb is a strong C, N compound forming element and can play a role in refining austenite grains, a small amount of niobium is added into steel to form a certain amount of nano-scale fine two-phase particles, so that the austenite grains can be prevented from growing, and the ductility and toughness of the steel can be improved, therefore, the quenched martensite lath has smaller size, and the strength and the ductility and toughness of the steel are greatly improved. Therefore, the content of the Nb is controlled to be 0.056-0.065%, and the preferable weight percentage of the Nb is 0.059-0.065%.
The first and second pass reduction rates are controlled to be not less than 50%, and the finishing rolling temperature is controlled to be 930-950 ℃, so that the method can effectively increase distortion energy, refine grains, and control the growth of the grains by matching with proper rolling temperature.
The coiling temperature is controlled to be 690-720 ℃, because the uniform structure and the dispersed carbide particles can be effectively obtained, the coiling shape of the steel coil can be effectively controlled, and the batch stable manufacturing is convenient to realize.
The blank is heated to 850-880 ℃ at the heating speed of 8-12 ℃/s, and is kept at the temperature for 360-600 s, preferably heated to 850-873 ℃ at the heating speed of 10-12 ℃/s, and kept at the temperature for 395-600 s, so that the uniform distribution of each component element in the steel on austenite can be effectively ensured, and favorable conditions are provided for the regulation and control of each subsequent phase.
The cooling speed is controlled to be 30-50 ℃/s during forming, the cooling speed is preferably controlled to be 36-44 ℃/s, the metallographic structure of the formed part at room temperature is 88-93% in terms of martensite volume content, 2-5% in terms of bainite volume content and 5-7% in terms of residual austenite volume content, and uniform phase distribution, types and proportions of the phases can be effectively obtained, so that guarantee is provided for obtaining high-strength product of the final product.
Compared with the prior art, the invention has the advantages that the yield strength is more than or equal to 1080MPa, the tensile strength is more than or equal to 1855MPa, the elongation is more than or equal to 8.6 percent, the product of strength and elongation can be further increased to 17.8-20.4 GPa, and the requirements of the lightweight structural part of the luxurious electric automobile on the strength and the collision energy absorption characteristics of the 2000 MPa-level high-collision-resistant part are completely met.
Drawings
FIG. 1 is a metallographic structure diagram according to the present invention.
Detailed Description
The present invention is described in detail below:
table 1 is a list of values of the components of each example and comparative example of the present invention;
table 2 shows the values of the process parameters of the examples and comparative examples of the present invention;
table 3 is a table of the results of mechanical property measurements of the examples and comparative examples of the present invention.
The preparation method comprises the following steps:
1) desulfurizing molten iron, and controlling S to be less than or equal to 0.001%;
2) smelting and refining in an electric furnace or a converter;
3) continuous casting is carried out, the superheat degree of the tundish molten steel is controlled to be 15-35 ℃, the thickness of a casting blank is 50-70 mm, and the blank drawing speed is 3.0-5.0 m/min;
4) carrying out primary descaling on the casting blank, and controlling the pressure of descaling water to be not lower than 190 bar;
5) soaking the casting blank, and controlling the discharging temperature of the casting blank to be 1230-1260 ℃;
6) carrying out secondary descaling on the casting blank, and controlling the pressure of descaling water to be not lower than 230 bar;
7) rolling: and controlling the thickness of a finish rolling outlet to be 0.80-4.0 mm; controlling the first and second pass reduction rates to be not less than 50%; controlling the finish rolling temperature to be 930-950 ℃;
8) laminar cooling to coiling temperature;
9) coiling, wherein the coiling temperature is controlled to be 690-720 ℃;
10) directly uncoiling and blanking or blanking after acid cleaning to obtain a blank of the structural part to be prepared;
11) heating the blank to 850-880 ℃ at the heating speed of 8-12 ℃/s, and preserving heat for 360-600 s at the temperature;
12) stamping forming: stamping the heated blank into an automobile structural member to be prepared, wherein the cooling speed is controlled to be 30-50 ℃/s, and the metallographic structure of the formed member at room temperature is controlled to be that the volume content of martensite is 88-93%, the volume content of bainite is 2-5%, and the volume content of retained austenite is 5-7%;
13) and cleaning, trimming and cutting the surface of the part.
TABLE 1 chemical composition (wt.%) of inventive and comparative examples
TABLE 2 tabulation of values of main process parameters for each example of the invention and comparative example
TABLE 3 tabulation of mechanical Properties of each example of the invention and comparative example
In conclusion, the invention successfully realizes that the invented steel not only has higher strength, but also has high plasticity through the matching design of components and processes, completely meets the requirements of the lightweight of luxury electric automobile structural parts on the strength and the collision energy absorption characteristic of 2000 MPa-grade high-collision-resistant performance parts, and has great significance for promoting the development of the lightweight of automobiles.
The present embodiments are merely preferred examples, and are not intended to limit the scope of the present invention.
Claims (9)
1. A steel for producing a high-plasticity and toughness automobile structural part with the tensile strength of 2000MPa by using CSP comprises the following chemical components in percentage by weight: c: 0.33 to 0.40%, Si: 1.66-2.05%, Mn: 2.00-2.80%, P: 0.010% or less, S: 0.005% or less, Als: 0.010-0.050%, Cr: 0.56-0.70%, Nb 0.056-0.065%, Ni: 0.20-0.30%, N: less than 0.004%, and the balance of Fe and inevitable impurities; the metallographic structure is as follows: the volume content of martensite is 88-93%, the volume content of bainite is 2-5%, and the volume content of residual austenite is 5-7%.
2. The steel for manufacturing high-ductility and toughness automotive structural parts with tensile strength of 2000MPa by using CSP according to claim 1, wherein: the weight percentage of the Si is 1.72-2.05%.
3. The steel for manufacturing high-ductility and toughness automotive structural parts with tensile strength of 2000MPa by using CSP according to claim 1, wherein: the weight percentage of Mn is 2.36-2.80%.
4. The steel for manufacturing high-ductility and toughness automotive structural parts with tensile strength of 2000MPa by using CSP according to claim 1, wherein: the weight percentage of the Cr is 0.61-0.70%.
5. The steel for manufacturing high-ductility and toughness automotive structural parts with tensile strength of 2000MPa by using CSP according to claim 1, wherein: the weight percentage of Nb is 0.059-0.065%.
6. The steel for manufacturing high-ductility and toughness automotive structural parts with tensile strength of 2000MPa by using CSP according to claim 1, wherein: the weight percentage of the Ni is 0.23-0.30%.
7. The method for producing a steel for a highly ductile and ductile automotive structural member having a tensile strength of 2000MPa by using a CSP, according to claim 1, comprising the steps of:
1) desulfurizing molten iron, and controlling S to be less than or equal to 0.001%;
2) smelting and refining in an electric furnace or a converter;
3) continuous casting is carried out, the superheat degree of the tundish molten steel is controlled to be 15-35 ℃, the thickness of a casting blank is 50-70 mm, and the blank drawing speed is 3.0-5.0 m/min;
4) carrying out primary descaling on the casting blank, and controlling the pressure of descaling water to be not lower than 190 bar;
5) soaking the casting blank, and controlling the discharging temperature of the casting blank to be 1230-1260 ℃;
6) carrying out secondary descaling on the casting blank, and controlling the pressure of descaling water to be not lower than 230 bar;
7) rolling: and controlling the thickness of a finish rolling outlet to be 0.80-4.0 mm; controlling the first and second pass reduction rates to be not less than 50%; controlling the finish rolling temperature to be 930-950 ℃;
8) laminar cooling to coiling temperature;
9) coiling, wherein the coiling temperature is controlled to be 690-720 ℃;
10) directly uncoiling and blanking or blanking after acid cleaning to obtain a blank of the structural part to be prepared;
11) heating the blank to 850-880 ℃ at the heating speed of 8-12 ℃/s, and preserving heat for 360-600 s at the temperature;
12) stamping forming: stamping the heated blank into an automobile structural member to be prepared, wherein the cooling speed is controlled to be 30-50 ℃/s, and the metallographic structure of the formed member at room temperature is controlled to be that the volume content of martensite is 88-93%, the volume content of bainite is 2-5%, and the volume content of retained austenite is 5-7%;
13) and cleaning, trimming and cutting the surface of the part.
8. The method for producing a steel for a high-ductility and toughness automotive structural member having a tensile strength of 2000MPa by using a CSP, according to claim 7, wherein: the blank is heated to 850-873 ℃ at the heating speed of 10-12 ℃/s, and the temperature is kept for 395-600 s at the temperature.
9. The method for producing a steel for a high-ductility and toughness automotive structural member having a tensile strength of 2000MPa by using a CSP, according to claim 7, wherein: and controlling the cooling speed to be 36-44 ℃/s in the punch forming.
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| CN114770037A (en) * | 2022-03-30 | 2022-07-22 | 东风汽车集团股份有限公司 | Manufacturing and assembling method of lightweight vehicle door bumper bar |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110029274A (en) * | 2019-04-25 | 2019-07-19 | 首钢集团有限公司 | A kind of 1600MPa grades of High-strength high-plasticity drop stamping steel and preparation method thereof |
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2021
- 2021-06-21 CN CN202110683520.7A patent/CN113528948A/en active Pending
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110029274A (en) * | 2019-04-25 | 2019-07-19 | 首钢集团有限公司 | A kind of 1600MPa grades of High-strength high-plasticity drop stamping steel and preparation method thereof |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114770037A (en) * | 2022-03-30 | 2022-07-22 | 东风汽车集团股份有限公司 | Manufacturing and assembling method of lightweight vehicle door bumper bar |
| CN114770037B (en) * | 2022-03-30 | 2023-10-24 | 东风汽车集团股份有限公司 | Manufacturing and assembling method of lightweight car door bumper |
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Application publication date: 20211022 |