CN113416889A - Ultrahigh-strength hot-dip galvanized DH1470 steel with good welding performance and preparation method thereof - Google Patents
Ultrahigh-strength hot-dip galvanized DH1470 steel with good welding performance and preparation method thereof Download PDFInfo
- Publication number
- CN113416889A CN113416889A CN202110555894.0A CN202110555894A CN113416889A CN 113416889 A CN113416889 A CN 113416889A CN 202110555894 A CN202110555894 A CN 202110555894A CN 113416889 A CN113416889 A CN 113416889A
- Authority
- CN
- China
- Prior art keywords
- steel
- temperature
- hot
- strength
- continuous
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Classifications
-
- 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
-
- 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
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/26—Methods of annealing
-
- 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
- C21D6/00—Heat treatment of ferrous alloys
- C21D6/001—Heat treatment of ferrous alloys containing Ni
-
- 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
- C21D6/00—Heat treatment of ferrous alloys
- C21D6/005—Heat treatment of ferrous alloys containing Mn
-
- 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
- C21D6/00—Heat treatment of ferrous alloys
- C21D6/008—Heat treatment of ferrous alloys containing Si
-
- 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
-
- 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
- C21D9/0081—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for slabs; for billets
-
- 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
-
- 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
-
- 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
- C22C38/08—Ferrous alloys, e.g. steel alloys containing nickel
-
- 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
- C22C38/12—Ferrous alloys, e.g. steel alloys containing tungsten, tantalum, molybdenum, vanadium, or niobium
-
- 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
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
- C23C2/04—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor characterised by the coating material
- C23C2/06—Zinc or cadmium or alloys based thereon
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
- C23C2/34—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor characterised by the shape of the material to be treated
- C23C2/36—Elongated material
- C23C2/40—Plates; Strips
-
- 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
-
- 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
- C21D2211/003—Cementite
-
- 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
- C21D2211/005—Ferrite
-
- 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
- C21D2211/009—Pearlite
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Heat Treatment Of Sheet Steel (AREA)
- Coating With Molten Metal (AREA)
Abstract
The invention provides ultrahigh-strength hot-dip galvanized DH1470 steel with good welding performance and a preparation method thereof, wherein the steel comprises the following elements in percentage by mass: c: 0.18-0.26%, Mn: 2.0% -2.9%, Si: 0.2% -1.2%, Al: 0.5% -1.6%, Mo: 0.30% -0.80%, Ni: 0.20-0.90%, P is less than or equal to 0.01%, S is less than or equal to 0.01%, Nb: 0-0.10%, V: 0.015 to 0.15 percent of Ti: 0.02 to 0.20 percent, and the balance of Fe and inevitable impurities; the preparation method comprises smelting, continuous casting of medium and thin slabs, hot continuous rolling, acid pickling and cold rolling, continuous hot galvanizing and finishing; the DH1470 hot-dip galvanized product produced by the method can realize the yield strength of 1000-1350 MPa in longitudinal sampling, the tensile strength of 1470-1650 MPa, the elongation of A80 after fracture is more than or equal to 8.0 percent, and the hole expansion rate is more than or equal to 13 percent.
Description
Technical Field
The invention belongs to the technical field of cold-rolled steel, and relates to a 1.5GPa grade cold-rolled hot-dip galvanized DH steel strip with excellent welding performance for an ultrahigh-strength automobile and a preparation method thereof.
Background
In recent years, with the higher and higher requirements of the automotive industry on the formability index of materials, the traditional dual-phase steel has difficulty in meeting the requirements of complex stamping parts on high ductility, and the TRIP steel has limited the wide use due to the expensive production cost caused by high alloy content. The existing DH steel introduces a certain amount of residual austenite into the traditional dual-phase steel, so that the material shows excellent forming performance through the TRIP effect, the defects of DP steel and TRIP steel in the application process can be obviously overcome, and the DH steel is just one of the research hotspots in the field of automobile steel development at present. However, in the process of connecting and applying the key components of the ultra-high strength steel, the welding quality is often fluctuated due to the narrow welding window, and even the cracking phenomenon occurs at the welding seam in the subsequent service, which seriously affects the safety performance of the components, so the welding performance of the ultra-high strength steel is greatly concerned by manufacturers and users. Based on the above current research situation, the present invention is to develop a novel ultra-high strength cold-rolled hot-dip galvanized DH1470 automotive steel with excellent welding performance, because the problems of poor formability and difficult welding of the ultra-high strength automotive steel are urgently needed to be solved.
Patent document CN 11164777732 a discloses 1300MPa grade complex phase steel, its preparation method and application, its main chemical components are: c: 0.1-0.15%, Si: 0.1-0.3%, Mn: 1.8-2.6%, Cr: 0.3-0.7%, Mo: 0.1-0.3%, P is less than or equal to 0.010%, S is less than or equal to 0.006%, Ti: 0.01-0.03%, Nb: 0.01-0.03%, Alt: 0.02-0.07%, B: 0.002-0.005% of Fe and inevitable impurities. The invention adopts a cold rolling-continuous annealing production process to produce the cold-rolled complex phase steel with the strength level of 1300MPa, the strength level does not reach 1.5GPa level, the product ductility is poor, and the forming problems such as stamping cracking and the like and the application problems such as unstable welding performance and the like are easy to occur in the practical application process.
Patent document CN 109207841 a discloses a low-cost high-formability 1180MPa grade cold-rolled annealed dual-phase steel plate and a manufacturing method thereof, wherein the main chemical components are as follows: : c: 0.1% -0.125%, Si: 0.4-0.8%, Mn: 2.6% -2.9%, Al: 0.01 to 0.05 percent, Nb: 0.01-0.03%, Ti: 0.01-0.03%, and the balance of Fe and other unavoidable impurities. The invention adopts a cold rolling-continuous annealing production process to produce the cold-rolled dual-phase steel with the strength level of 1200MPa, the strength level is far from being insufficient, the product has very poor plasticity, and the ultrahigh strength and better ductility and formability are difficult to combine.
Disclosure of Invention
Aiming at the problems in the prior art, the invention aims to develop and provide a 1.5GPa grade ultra-high strength cold-rolled hot-dip galvanized DH steel plate with excellent welding performance, hole expanding performance and ductility and a preparation method thereof.
The specific technical scheme is as follows:
the ultrahigh-strength hot-dip galvanized DH1470 steel with good welding performance comprises the following elements in percentage by mass: c: 0.18-0.26%, Mn: 2.0% -2.9%, Si: 0.2% -1.2%, Al: 0.5% -1.6%, Mo: 0.30% -0.80%, Ni: 0.20-0.90%, P is less than or equal to 0.01%, S is less than or equal to 0.01%, Nb: 0-0.10%, V: 0.015 to 0.15 percent of Ti: 0.02 to 0.20 percent, and the balance of Fe and inevitable impurities.
The microstructure of the DH1470 steel plate is ferrite, martensite, residual austenite and bainite; the microstructure of the steel plate is as follows by volume percent: 1-15% of ferrite, 60-80% of martensite, 3-12% of residual austenite and 3-15% of bainite; the residual austenite in the product of the invention is in two forms of block and film, the grain size is between 0.05 mu m and 0.50 mu m, the block residual austenite is mainly distributed at the interface of martensite/ferrite and in the ferrite, and the film residual austenite is mainly distributed between martensite laths.
The yield strength of the DH1470 steel plate is 1000-1350 MPa, the tensile strength is 1470-1650 MPa, the elongation after breakage of A80 is more than or equal to 8.0%, and the hole expansion rate is more than or equal to 13%; the requirements of high strength, high plasticity and high hole expanding performance of the automobile are met.
The reason for the alloy design of the present invention is as follows:
c: the carbon element guarantees the strength requirement of the steel through solid solution strengthening, and free carbon can play a good stabilizing effect on austenite, so that the forming performance of the steel is improved. The content of the element C is too low, so that a proper amount of residual austenite is difficult to obtain, and the mechanical property index of the steel in the invention cannot be met; too high a content can embrittle the steel, increasing costs and also presenting a delayed fracture risk. Therefore, the content of the C element is controlled to be 0.18-0.26 percent in the invention.
Mn: manganese is an austenite stabilizing element in steel, can expand an austenite phase region, reduce the critical quenching speed of the steel, and can refine grains, thereby being beneficial to solid solution strengthening to improve the strength. The content of Mn element is too low, the super-cooled austenite is not stable enough, and the plasticity, the toughness and other processing performances of the steel plate are reduced; the excessively high content of the Mn element causes deterioration in the weldability of the steel sheet, and increases in the production cost, which is not favorable for industrial production. Therefore, the content of the Mn element is controlled to be 2.0-2.9 percent.
Si: the silicon element has a certain solid solution strengthening effect in ferrite, so that the steel has enough strength, and meanwhile, the Si can inhibit the decomposition of residual austenite and the precipitation of carbide, thereby reducing the inclusion in the steel. The Si element content is too low to play a role in strengthening; the dense Mn is easily formed on the surface of the steel plate when the content of the Si element is too high2SiO4An oxide layer, which reduces the galvanized surface quality of the steel sheet. Therefore, the content of the Si element is controlled to be 0.2 to 1.2 percent in the invention.
Al: the aluminum element contributes to deoxidation of molten steel and can also suppress decomposition of residual austenite and precipitation of carbide. Too high content of Al element not only increases production cost, but also causes difficulties in continuous casting production, etc. Therefore, the content of the Al element is controlled within the range of 0.5 to 1.6 percent in the invention.
Mo: the molybdenum element is a strengthening element in the steel, is beneficial to stabilizing the retained austenite, has a remarkable effect of improving the hardenability of the steel, can improve the strength of a welding seam by adding the Mo element, refines the tissue structure of the welding seam, and combines high strength and high toughness with Ti, so that the welding performance of the steel can be improved and good comprehensive mechanical properties can be kept. The invention controls the content range of the Mo element at 0.3-0.8%.
Ni: the nickel element is an important element for improving the welding performance of steel, and the addition of the Ni is beneficial to improving the toughness of a welding seam, particularly the low-temperature impact toughness and reducing the brittle transition temperature; the Cr-Cr alloy is reasonably matched with Cr, so that the phase transformation process of weld metal can be effectively controlled, and a composite structure of martensite and a certain proportion of retained austenite is obtained, thereby giving consideration to high crack resistance and high strength. The invention controls the content range of Ni element at 0.2% -0.9%.
P: the P element is a harmful element in steel, seriously reduces the plasticity and the deformability of the steel, and the lower the content, the better the content. In the invention, the content of the P element is controlled to be less than or equal to 0.01 percent in consideration of the cost.
S: the S element is a harmful element in steel, seriously affects the formability of steel, and the lower the content, the better the formability. In the invention, the content of the S element is controlled to be less than or equal to 0.01 percent in consideration of the cost.
Nb: the microalloying element Nb is used for improving the comprehensive performance of the material through fine grain strengthening, and can be added with Nb of not more than 0.1 percent according to the actual situation, and in order to control the production cost, the microalloying element Nb can not be added.
V: the microalloying element vanadium mainly exists in a VC form, the strength and the fatigue resistance of the material are improved through fine grain strengthening and dispersion strengthening, and undissolved VC particles can pin ferrite grain boundaries in the hot galvanizing annealing heating process, so that the effect of refining grains is achieved; when the annealing temperature is increased to a two-phase region, the VC is low in dissolving temperature, so that the VC is fully dissolved in a matrix, and solid-solution C atoms are enriched into austenite to improve the stability of the VC; during the annealing process, VC in the ferrite is separated out again, thereby producing obvious precipitation strengthening. Therefore, in the invention, the content of the V element is controlled to be 0.015 to 0.15 percent.
Ti: the grain size can be refined by adding a small amount of Ti element, the precipitates can pin dislocation to play a role in delaying the expansion of a crack source at a welding seam, and the toughness of the material is obviously improved, and in the invention, the content of the Ti element is controlled to be 0.02-0.20 percent.
The second technical scheme of the invention also provides a preparation method of the ultrahigh-strength hot-dip galvanized DH1470 steel with good welding performance, which comprises the following steps: smelting, continuous casting of medium and thin slabs, hot continuous rolling, acid pickling and cold rolling, continuous hot galvanizing and finishing. The preparation process comprises the following specific steps:
(1) smelting: smelting by a converter to obtain molten steel meeting the following component requirements in percentage by mass, C: 0.18-0.26%, Mn: 2.0% -2.9%, Si: 0.2% -1.2%, Al: 0.5% -1.6%, Mo: 0.30% -0.80%, Ni: 0.20-0.90%, P is less than or equal to 0.01%, S is less than or equal to 0.01%, Nb: 0-0.10%, V: 0.015 to 0.15 percent of Ti: 0.02-0.20 percent, and the balance of Fe and inevitable impurities, wherein the temperature of the molten steel is 1630-1740 ℃.
(2) Continuous casting of medium and thin slabs: the casting temperature is 1550-1650 ℃, and the thickness of the continuous casting billet is 120-180 mm.
(3) Hot continuous rolling: the charging temperature of the casting blank is 550-680 ℃, the heating temperature is 1160-1300 ℃, the initial rolling temperature is 1030-1150 ℃, the final rolling temperature is above 910 ℃, and the coiling temperature is 600-700 ℃. The thickness of the hot rolled coil is 2-4 mm;
the hot rolled steel plate structure is as follows: the hot-rolled microstructure of the product is ferrite, pearlite, bainite and a small amount of cementite. The steel plate structure comprises the following components in percentage by volume: 20-40% of ferrite, 40-60% of pearlite, 5-20% of bainite and 1-5% of cementite.
(4) Acid pickling and cold rolling: the iron scale on the surface of the steel coil is removed by acid liquor before cold rolling, and the cold rolling reduction rate is 30-50%. The rolling reduction is too high, so that the deformation resistance is too high, and the rolling is difficult to reach the target thickness; the reduction ratio is too low, resulting in a decrease in the elongation of the cold-rolled steel sheet.
(5) Continuous hot galvanizing: the preheating temperature is controlled to be 440-620 ℃, the heating temperature is 800-950 ℃, the annealing time is 30-300 s, the slow cooling outlet temperature is 700-760 ℃, then the steel is rapidly cooled, the rapid cooling rate is more than 20 ℃/s, the rapid cooling temperature is 450-470 ℃, the galvanizing temperature is 450-470 ℃, the steel strip is cooled to 400-420 ℃ firstly after the galvanizing is finished, then the steel strip is cooled by air cooling, and the temperature of a top roller of a cooling tower is controlled to be 250-300 ℃;
the annealing temperature is 750-880 ℃, and if the annealing temperature is too high, the ductility of the steel is reduced due to complete austenitizing and insufficient ferrite proportion; if the annealing temperature is too low, the proportion of soft phase ferrite in the final material is too high, which may significantly reduce the strength of the material. The annealing time is 30-300 s, if the annealing time is too long, the grains of the steel plate are coarse, the annealing time is too short, and the elongation of the steel plate is reduced because the steel plate does not finish the annealing and recrystallization processes in an urgent manner; the temperature of the quick cooling outlet is 450-470 ℃, the temperature is close to the temperature of a zinc pot, so that the zinc plating is convenient, the strip steel is cooled to 400-420 ℃ after being discharged out of the zinc pot, the normal solidification of the surface of a zinc layer is ensured, and the flowing of zinc liquid is prevented; the temperature of the cooling tower top roller is controlled to be 250-300 ℃, so that the zinc layer can be completely solidified, and the influence on the quality of a coating layer caused by roller adhesion is avoided.
(6) Finishing: the finishing elongation is controlled within the range of 0.05-0.20%.
The microstructure of the steel plate is 1-15% (volume ratio) ferrite, 60-80% (volume ratio) martensite, 3-12% (volume ratio) retained austenite and 3-15% (volume ratio) bainite structure, and the total is 100%; the residual austenite in the product of the invention is in two forms of block and film, the grain size is between 0.05 mu m and 0.50 mu m, the block residual austenite is mainly distributed at the interface of martensite/ferrite and in the ferrite, and the film residual austenite is mainly distributed between martensite laths.
The cold-rolled hot-dip galvanized DH1470 steel plate for the automobile, which has the yield strength of 1000-1350 MPa, the tensile strength of 1470-1650 MPa, the elongation after breakage of A80 of not less than 8.0%, the hole expansion rate of not less than 13% and the thickness specification of 1.0-1.8 mm, has good welding performance, ultrahigh strength, high plasticity and high hole expansion performance, can be obtained by the method.
The invention has the beneficial effects that:
(1) the invention adopts the production process of converter smelting, medium and thin slab continuous casting, hot continuous rolling, acid pickling and cold rolling and continuous hot dipping zinc, can realize the industrial production of DH1470 hot dipping zinc products on the traditional cold rolling hot dipping zinc dual-phase steel production line, and has the advantages of low cost, no need of adding new production equipment and stable production process.
(2) The DH1470 hot-dip galvanized product produced by the invention introduces residual austenite and a small amount of bainite on the basis of the traditional cold-rolled hot-dip galvanized dual-phase steel, and realizes the characteristics of excellent welding performance, high strength and high plasticity under the coupling action of transformation induced plasticity (TRIP) effect assistance and bainite coordinated deformation.
(3) The DH1470 hot-dip galvanized product produced by the method can realize the longitudinal sampling yield strength of 1000-1350 MPa, the tensile strength of 1470-1650 MPa, the elongation after A80 fracture of more than or equal to 8.0 percent, the hole expansion rate of more than or equal to 13 percent and the thickness specification of 1.0-1.8 mm, the welding current is 4.2-8.2 kA when a spot welding process window is tested, the welding time is 300-540 ms, and the welding process window is far larger than the welding window of DP products with the same strength level.
(4) The structure of the finished steel plate comprises 1-15% of ferrite, 60-80% of martensite, 3-12% of residual austenite and 3-15% of bainite according to volume percentage; the residual austenite in the product of the invention is in two forms of block and film, the grain size is between 0.05um and 0.50um, the block residual austenite is mainly distributed at the interface of martensite/ferrite and in the ferrite, and the film residual austenite is mainly distributed between martensite laths.
Drawings
FIG. 1 is a metallographic microstructure of a steel sheet of example 1;
FIG. 2 is an engineering stress-strain curve of example 1.
Detailed Description
The present invention is further illustrated by the following examples.
According to the embodiment of the invention, smelting, medium and thin slab continuous casting, hot continuous rolling, acid pickling and cold rolling, continuous hot galvanizing and finishing are carried out according to the component proportion of the technical scheme.
1) Smelting: the temperature of the converter smelting molten steel is 1630-1740 ℃;
(2) continuous casting of medium and thin slabs: the casting temperature is 1550-1650 ℃, and the thickness of the continuous casting billet is 120-180 mm;
(3) hot continuous rolling: the charging temperature of the casting blank is 550-680 ℃, the heating temperature is 1160-1300 ℃, the initial rolling temperature is 1030-1150 ℃, the final rolling temperature is above 910 ℃, and the coiling temperature is 600-700 ℃; the hot-rolled steel plate obtained after hot continuous rolling has the following structure: ferrite, pearlite, bainite and a small amount of cementite. The steel plate structure comprises the following components in percentage by volume: 20-40% of ferrite, 40-60% of pearlite, 5-20% of bainite and 1-5% of cementite.
(4) Acid pickling and cold rolling: the cold rolling reduction rate is 30-50%;
(5) continuous hot galvanizing: the preheating temperature is 440-620 ℃, the annealing temperature is 800-950 ℃, the annealing time is 30-300 s, the slow cooling temperature is 700-760 ℃, then the steel is rapidly cooled, the rapid cooling rate is more than 20 ℃/s, the rapid cooling temperature is 450-470 ℃, the galvanizing temperature is 450-470 ℃, the steel strip is cooled to 400-420 ℃ after the galvanizing is finished, then the steel strip is cooled by air cooling, and the temperature of a top roller of a cooling tower is controlled to be 250-300 ℃;
(6) finishing: the finishing elongation is controlled within the range of 0.05-0.20%.
The compositions of the steels of the examples of the invention are shown in table 1. The main process parameters of the continuous casting and hot rolling of the steel of the embodiment of the invention are shown in Table 2. The main process parameters of the continuous galvanizing of the steel of the embodiment of the invention are shown in Table 3. The structure of the steel of the examples of the present invention is shown in Table 4. The properties of the steels of the examples of the invention are shown in Table 5.
TABLE 1 composition (wt%) of steels of examples of the present invention
| Examples | C | Mn | Si | P | S | Al | Mo | Ni | Nb | V | Ti |
| 1 | 0.24 | 2.27 | 0.53 | 0.003 | 0.001 | 0.82 | 0.44 | 0.55 | 0.032 | 0.018 | 0.041 |
| 2 | 0.22 | 2.58 | 0.76 | 0.005 | 0.001 | 0.67 | 0.63 | 0.38 | 0.012 | 0.034 | 0.039 |
| 3 | 0.26 | 2.44 | 0.35 | 0.005 | 0.003 | 0.58 | 0.46 | 0.27 | - | 0.045 | 0.145 |
| 4 | 0.21 | 2.72 | 1.13 | 0.004 | 0.002 | 1.13 | 0.52 | 0.72 | - | 0.142 | 0.066 |
| 5 | 0.20 | 2.82 | 0.65 | 0.002 | 0.004 | 1.36 | 0.34 | 0.52 | 0.024 | 0.067 | 0.061 |
| 6 | 0.19 | 2.53 | 1.14 | 0.003 | 0.002 | 0.95 | 0.53 | 0.48 | - | 0.075 | 0.046 |
| 7 | 0.26 | 2.06 | 0.67 | 0.001 | 0.005 | 0.88 | 0.66 | 0.65 | 0.052 | 0.058 | 0.121 |
| 8 | 0.23 | 2.47 | 0.52 | 0.004 | 0.001 | 0.74 | 0.75 | 0.40 | - | 0.024 | 0.178 |
| 9 | 0.22 | 2.30 | 0.95 | 0.006 | 0.001 | 0.85 | 0.54 | 0.64 | 0.023 | 0.025 | 0.047 |
| 10 | 0.21 | 2.58 | 1.03 | 0.001 | 0.004 | 0.68 | 0.36 | 0.57 | 0.018 | 0.046 | 0.026 |
| 11 | 0.18 | 2.44 | 1.06 | 0.003 | 0.003 | 1.32 | 0.59 | 0.86 | - | 0.071 | 0.166 |
| 12 | 0.25 | 2.05 | 0.72 | 0.004 | 0.005 | 1.05 | 0.45 | 0.39 | - | 0.118 | 0.055 |
TABLE 2 Main Process parameters for continuous casting and Hot Rolling of steels according to examples of the invention
TABLE 3 Main Process parameters for continuous galvanization of the steels of the examples of the invention
TABLE 4 Structure of inventive example steels
TABLE 5 Properties of steels of examples of the invention
Therefore, the cold-rolled hot-galvanized DH1180 steel plate prepared by adopting the component design, rolling and continuous annealing process has the performance meeting the performance requirements of yield strength of 1000-1350 MPa, tensile strength of 1470-1650 MPa, elongation of A80 after fracture of more than or equal to 8.0%, hole expansion rate of more than or equal to 13%, thickness specification of 1.0-1.8 mm, excellent welding performance, high strength, high plasticity, high hole expansion rate and the like of the automobile steel.
In order to express the present invention, the above embodiments are properly and fully described by way of examples, and the above embodiments are only used for illustrating the present invention and not for limiting the present invention, and those skilled in the relevant art can make various changes and modifications without departing from the spirit and scope of the present invention, and any modifications, equivalent substitutions, improvements, etc. made by the persons skilled in the relevant art should be included in the protection scope of the present invention, and the protection scope of the present invention should be defined by the claims.
Claims (5)
1. The ultrahigh-strength hot-dip galvanized DH1470 steel with good welding performance is characterized in that the steel comprises the following elements in percentage by mass: c: 0.18-0.26%, Mn: 2.0% -2.9%, Si: 0.2% -1.2%, Al: 0.5% -1.6%, Mo: 0.30% -0.80%, Ni: 0.20-0.90%, P is less than or equal to 0.01%, S is less than or equal to 0.01%, Nb: 0-0.10%, V: 0.015 to 0.15 percent of Ti: 0.02 to 0.20 percent, and the balance of Fe and inevitable impurities.
2. The DH1470 steel plate with ultrahigh strength and good welding performance of claim 1, wherein the microstructure of the DH1470 steel plate is ferrite + martensite + residual austenite + bainite; the microstructure of the steel plate is as follows by volume percent: 1-15% of ferrite, 60-80% of martensite, 3-12% of residual austenite and 3-15% of bainite; the residual austenite is in two forms of block and film, the grain size is between 0.05 and 0.50 mu m, the block residual austenite is distributed at the martensite/ferrite interface and in the ferrite, and the film residual austenite is distributed between martensite laths.
3. The DH1470 steel of ultrahigh-strength hot dip galvanizing with good welding performance as claimed in claim 1, wherein the yield strength of the DH1470 steel plate is 1000-1350 MPa, the tensile strength is 1470-1650 MPa, the elongation after A80 breaking is not less than 8.0%, and the hole expansion rate is not less than 13%.
4. A method for preparing the ultrahigh-strength hot-dip galvanized DH1470 steel with good welding performance according to any one of claims 1 to 3, which comprises the steps of smelting, medium and thin slab continuous casting, hot continuous rolling, pickling and cold rolling, continuous hot-dip galvanizing and finishing; the method is characterized in that:
(1) smelting: the temperature of the converter smelting molten steel is 1630-1740 ℃;
(2) continuous casting of medium and thin slabs: the casting temperature is 1550-1650 ℃, and the thickness of the continuous casting billet is 120-180 mm;
(3) hot continuous rolling: the charging temperature of the casting blank is 550-680 ℃, the heating temperature is 1160-1300 ℃, the initial rolling temperature is 1030-1150 ℃, the final rolling temperature is above 910 ℃, and the coiling temperature is 600-700 ℃;
(4) acid pickling and cold rolling: the cold rolling reduction rate is 30-50%;
(5) continuous hot galvanizing: the preheating temperature is 440-620 ℃, the annealing temperature is 800-950 ℃, the annealing time is 30-300 s, the slow cooling temperature is 700-760 ℃, then the steel is rapidly cooled, the rapid cooling rate is more than 20 ℃/s, the rapid cooling temperature is 450-470 ℃, the galvanizing temperature is 450-470 ℃, the steel strip is cooled to 400-420 ℃ after the galvanizing is finished, then the steel strip is cooled by air cooling, and the temperature of a top roller of a cooling tower is controlled to be 250-300 ℃;
(6) finishing: the finishing elongation is controlled within the range of 0.05-0.20%.
5. The method for preparing the ultrahigh-strength hot-dip galvanized DH1470 steel with good welding performance according to the claim 4, wherein the method comprises the following steps: the hot-rolled steel plate obtained after the hot continuous rolling in the step (3) has the following structure: ferrite, pearlite, bainite and a small amount of cementite. The steel plate structure comprises the following components in percentage by volume: 20-40% of ferrite, 40-60% of pearlite, 5-20% of bainite and 1-5% of cementite.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110555894.0A CN113416889B (en) | 2021-05-21 | 2021-05-21 | Ultrahigh-strength hot-galvanized DH1470 steel with good welding performance and preparation method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110555894.0A CN113416889B (en) | 2021-05-21 | 2021-05-21 | Ultrahigh-strength hot-galvanized DH1470 steel with good welding performance and preparation method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN113416889A true CN113416889A (en) | 2021-09-21 |
| CN113416889B CN113416889B (en) | 2022-07-22 |
Family
ID=77712618
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110555894.0A Active CN113416889B (en) | 2021-05-21 | 2021-05-21 | Ultrahigh-strength hot-galvanized DH1470 steel with good welding performance and preparation method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113416889B (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115627424A (en) * | 2022-11-07 | 2023-01-20 | 鞍钢股份有限公司 | 1.5 GPa-grade novel high-plasticity cold-rolled DH steel and preparation method thereof |
| CN116043118A (en) * | 2023-01-19 | 2023-05-02 | 鞍钢股份有限公司 | Ultra-high reaming performance 980 MPa-grade hot dip galvanized complex phase steel and preparation method thereof |
| CN116043119A (en) * | 2023-01-19 | 2023-05-02 | 鞍钢股份有限公司 | Easily-welded ultra-high reaming performance 800 MPa-grade hot dip galvanized complex phase steel and preparation method thereof |
| WO2023246939A1 (en) * | 2022-06-22 | 2023-12-28 | 宝山钢铁股份有限公司 | High-strength and high formability cold-rolled hot-galvanized strip steel and manufacturing method therefor |
Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101942605A (en) * | 2010-09-13 | 2011-01-12 | 江小明 | Silico-manganese steel and manufacturing method thereof |
| US20160108492A1 (en) * | 2012-11-15 | 2016-04-21 | Baoshan Iron & Steel Co., Ltd. | High-formability and super-strength hot galvanizing steel plate and manufacturing method thereof |
| JP2017053009A (en) * | 2015-09-10 | 2017-03-16 | 新日鐵住金株式会社 | High strength hot-dip galvanized steel sheet excellent in elongation and hole expansibility and production method therefor |
| CN107636184A (en) * | 2015-06-11 | 2018-01-26 | 新日铁住金株式会社 | Alloyed hot-dip galvanized steel plate and its manufacture method |
| CN108367539A (en) * | 2015-12-15 | 2018-08-03 | 塔塔钢铁艾默伊登有限责任公司 | Strength hot dipped galvanized steel strips material |
| 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 |
| CN111455282A (en) * | 2020-05-11 | 2020-07-28 | 武汉钢铁有限公司 | Quenching distribution steel with tensile strength more than or equal to 1500MPa produced by adopting short process and method |
| CN112041475A (en) * | 2018-05-01 | 2020-12-04 | 日本制铁株式会社 | Galvanized steel sheet and method for producing same |
| CN112048680A (en) * | 2020-09-07 | 2020-12-08 | 鞍钢股份有限公司 | Alloyed hot-dip galvanized DH980 steel and preparation method thereof |
-
2021
- 2021-05-21 CN CN202110555894.0A patent/CN113416889B/en active Active
Patent Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101942605A (en) * | 2010-09-13 | 2011-01-12 | 江小明 | Silico-manganese steel and manufacturing method thereof |
| US20160108492A1 (en) * | 2012-11-15 | 2016-04-21 | Baoshan Iron & Steel Co., Ltd. | High-formability and super-strength hot galvanizing steel plate and manufacturing method thereof |
| CN107636184A (en) * | 2015-06-11 | 2018-01-26 | 新日铁住金株式会社 | Alloyed hot-dip galvanized steel plate and its manufacture method |
| JP2017053009A (en) * | 2015-09-10 | 2017-03-16 | 新日鐵住金株式会社 | High strength hot-dip galvanized steel sheet excellent in elongation and hole expansibility and production method therefor |
| CN108367539A (en) * | 2015-12-15 | 2018-08-03 | 塔塔钢铁艾默伊登有限责任公司 | Strength hot dipped galvanized steel strips material |
| CN112041475A (en) * | 2018-05-01 | 2020-12-04 | 日本制铁株式会社 | Galvanized steel sheet and method for producing same |
| 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 |
| CN111455282A (en) * | 2020-05-11 | 2020-07-28 | 武汉钢铁有限公司 | Quenching distribution steel with tensile strength more than or equal to 1500MPa produced by adopting short process and method |
| CN112048680A (en) * | 2020-09-07 | 2020-12-08 | 鞍钢股份有限公司 | Alloyed hot-dip galvanized DH980 steel and preparation method thereof |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2023246939A1 (en) * | 2022-06-22 | 2023-12-28 | 宝山钢铁股份有限公司 | High-strength and high formability cold-rolled hot-galvanized strip steel and manufacturing method therefor |
| CN115627424A (en) * | 2022-11-07 | 2023-01-20 | 鞍钢股份有限公司 | 1.5 GPa-grade novel high-plasticity cold-rolled DH steel and preparation method thereof |
| CN115627424B (en) * | 2022-11-07 | 2023-08-18 | 鞍钢股份有限公司 | 1.5 GPa-grade high-plasticity cold-rolled DH steel and preparation method thereof |
| CN116043118A (en) * | 2023-01-19 | 2023-05-02 | 鞍钢股份有限公司 | Ultra-high reaming performance 980 MPa-grade hot dip galvanized complex phase steel and preparation method thereof |
| CN116043119A (en) * | 2023-01-19 | 2023-05-02 | 鞍钢股份有限公司 | Easily-welded ultra-high reaming performance 800 MPa-grade hot dip galvanized complex phase steel and preparation method thereof |
| CN116043119B (en) * | 2023-01-19 | 2023-10-27 | 鞍钢股份有限公司 | Easily-welded ultra-high reaming performance 800 MPa-grade hot dip galvanized complex phase steel and preparation method thereof |
| CN116043118B (en) * | 2023-01-19 | 2023-10-27 | 鞍钢股份有限公司 | Ultra-high reaming performance 980 MPa-grade hot dip galvanized complex phase steel and preparation method thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| CN113416889B (en) | 2022-07-22 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN112048681B (en) | 980 MPa-grade high-formability cold-rolled DH steel and preparation method thereof | |
| CN109097705B (en) | 800 MPa-grade cold-rolled hot-galvanized dual-phase steel and production method thereof | |
| CN112048680B (en) | Alloyed hot-dip galvanized DH980 steel and preparation method thereof | |
| CN113416889B (en) | Ultrahigh-strength hot-galvanized DH1470 steel with good welding performance and preparation method thereof | |
| JP7150022B2 (en) | High-strength steel sheet with excellent workability and its manufacturing method | |
| CN113242912B (en) | Cold-rolled steel sheet and hot-dip galvanized steel sheet having excellent workability, and method for producing same | |
| CN113388779B (en) | 1.5 GPa-grade ultrahigh-strength high-plasticity high-hole-expansion DH steel plate and preparation method thereof | |
| CN113403550B (en) | High-plasticity fatigue-resistant cold-rolled hot-galvanized DH1180 steel plate and preparation method thereof | |
| CN110172640B (en) | 500 MPa-grade high-work-hardening-rate hot-dip galvanized dual-phase steel plate and preparation method thereof | |
| KR20150110723A (en) | 780 mpa class cold rolled dual-phase strip steel and manufacturing method thereof | |
| CN102199723A (en) | High-strength cold-rolled hot-galvanized precipitation reinforced steel and manufacturing method thereof | |
| CN104561812A (en) | 1,000 MPa-level high-aluminum hot-dip-galvanized dual-phase steel and preparation method thereof | |
| CN111979488B (en) | 780 MPa-grade alloying hot-dip galvanized DH steel and preparation method thereof | |
| CN113388773A (en) | 1.5GPa grade high-formability hydrogen-embrittlement-resistant ultrahigh-strength automobile steel and preparation method thereof | |
| CN114525452A (en) | Hot-galvanized low-alloy high-strength steel with yield strength of 700Mpa and preparation method thereof | |
| US11261503B2 (en) | Method for producing a flat steel product made of a manganese-containing steel, and such a flat steel product | |
| CN111373060A (en) | High-strength hot-rolled flat steel product having a high resistance to edge cracking and at the same time a high bake-hardening potential, and method for producing such a flat steel product | |
| KR102200227B1 (en) | Cord rolled steel sheet, hot-dip galvanized steel sheet having good workability, and manufacturing method thereof | |
| CN114921726A (en) | Low-cost high-yield-ratio cold-rolled hot-galvanized ultrahigh-strength steel and production method thereof | |
| CN114686762A (en) | Production method of high-strength and high-toughness hot continuous rolling thin steel plate with Brinell hardness of 500HBW | |
| CN112095047B (en) | Cold-rolled hot-dip galvanized DH780 steel with excellent welding performance and preparation method thereof | |
| CN113737108A (en) | Delay cracking resistant electro-galvanized super-strong dual-phase steel and manufacturing method thereof | |
| JP6379717B2 (en) | Method for producing alloyed hot-dip galvanized steel for hot stamping | |
| CN112048670B (en) | Cold-rolled hot-galvanized DH590 steel with excellent surface quality and production method thereof | |
| JP2002363685A (en) | Low yield ratio high strength cold rolled steel sheet |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |