CN110629000A - Cold-rolled hot-dip galvanized steel sheet with yield strength of 280MPa and manufacturing method thereof - Google Patents
Cold-rolled hot-dip galvanized steel sheet with yield strength of 280MPa and manufacturing method thereof Download PDFInfo
- Publication number
- CN110629000A CN110629000A CN201810659375.7A CN201810659375A CN110629000A CN 110629000 A CN110629000 A CN 110629000A CN 201810659375 A CN201810659375 A CN 201810659375A CN 110629000 A CN110629000 A CN 110629000A
- Authority
- CN
- China
- Prior art keywords
- hot
- rolling
- steel sheet
- cold
- dip galvanized
- 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.)
- Pending
Links
Classifications
-
- 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
- C21D8/0205—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips of ferrous alloys
-
- 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
- C21D8/0226—Hot rolling
-
- 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
-
- 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
- C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
- C21D8/0273—Final recrystallisation annealing
-
- 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
- C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
-
- 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%
-
- 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
- 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
- C22C38/14—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
- C21D2211/005—Ferrite
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Materials 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)
Abstract
The invention discloses a cold-rolled hot-dip galvanized steel sheet with 280 MPa-grade yield strength and a manufacturing method thereof, and mainly solves the technical problem that the manufacturing cost of the 280 MPa-grade cold-rolled hot-dip galvanized steel sheet in the prior art is high. The invention provides a cold-rolled hot-dip galvanized steel sheet with 280 MPa-grade yield strength, which comprises the following chemical components in percentage by weight: c: 0.0045-0.0085%, less than or equal to 0.050% of Si, Mn: 0.25-0.50%, P: 0.025-0.045%, S is less than or equal to 0.018%, Ti: 0.050-0.090%, B: 0.0003-0.0010%, N is less than or equal to 0.005%, Al: 0.015-0.060% of iron and inevitable impurities. Elongation after fracture A of hot-dip galvanized steel sheet with thickness of 0.35-0.80 mm80mmIs 32 to 38 percent. The hot dip galvanized steel sheet is mainly used in the household appliance industry.
Description
Technical Field
The invention relates to a cold-rolled hot-dip galvanized steel sheet, in particular to a cold-rolled hot-dip galvanized steel sheet with yield strength of 280MPa and a manufacturing method thereof, and specifically relates to a hot-dip galvanized gapless atomic steel sheet with yield strength of 280-320 MPa and a manufacturing method thereof, belonging to the technical field of iron-based alloy.
Background
Interstitial free steel (IF steel) is free from aging phenomenon because interstitial atoms in the steel are fixed by titanium or niobium elements to form carbon and nitride. After the IF steel cold rolling annealing product is baked after color coating, the yield platform does not appear in material stretching, so that compared with common carbon steel, the IF steel can better meet the requirement that the curved surface is not corrugated. However, the conventional IF steel has low strength, the yield strength is generally below 200MPa, and the IF steel cannot be well adapted to the application with certain strength requirement. Therefore, since the seventh and eighties of the twentieth century, solid solution strengthening elements such as P, Si, Mn, etc. have been added to ordinary IF steel to improve the strength of the steel sheet, and there is no interstitial space in the steel sheet to ensure excellent punching properties and no aging.
In recent years, with the development of industries such as household appliance manufacturing and the like and the fierce competition of the steel industry, the domestic household appliance industry has a further upgrading requirement in the panel manufacturing process, and the hot dip galvanized substrate for manufacturing the household appliance panel not only meets the requirements of no aging, no edge and no cracking in the subsequent baking color coating and production processing, particularly in curved surface bending forming, but also has high yield strength and high deformation resistance required by the material.
The components of the 340 MPa-grade high-strength IF steel disclosed in the Chinese patent document CN107012397A are greatly different from the design of the present patent in the design of carbon, manganese and titanium, the contents are respectively less than or equal to 0.005%, 0.15-0.35% and 0.030-0.045%, and the alloy steel is added with noble Nb element, the yield strength is 180-230MPa, the yield strength is low, and the processing and using requirements of the users can not be met.
The components of the high-strength IF steel disclosed in the patent of Chinese patent document CN103710617A and having hot-dip galvanized iron alloy with 340MPa are obviously different from the design of the high-strength IF steel in the design of carbon, silicon and titanium, the contents of the high-strength IF steel are respectively less than or equal to 0.004%, 0.04-0.10% and 0.005-0.015%, and the high-strength IF steel further contains noble Nb element, has the yield strength of 200-240MPa, and has low yield strength, so that the processing and using requirements of users of the same type can not be met.
The patent of Chinese patent document CN106854729A discloses a phosphorus-containing interstitial-free cold-rolled galvanized steel sheet and a manufacturing method thereof, the components of the steel sheet are greatly different from the design of the steel sheet in carbon and phosphorus design, and the contents are respectively less than or equal to 0.003 percent and 0.4 to 0.8 percent; the ultra-low carbon less than or equal to 0.003 percent is adopted in the patent design, so that the requirements on RH refining technology and time can be improved, and the production cost is increased; and the steel plate matrix is accelerated to corrode due to segregation caused by excessively high phosphorus elements (the mean value reaches 0.06%), and the surface quality requirement of subsequent galvanization is easily influenced due to the problem of surface color difference caused by over-pickling.
Disclosure of Invention
The invention aims to provide a cold-rolled hot-dip galvanized steel sheet with 280 MPa-grade yield strength and a manufacturing method thereof, and mainly solves the technical problem that the manufacturing cost of the 280 MPa-grade cold-rolled hot-dip galvanized steel sheet in the prior art is high.
The invention adopts the technical scheme that a cold-rolled hot-dip galvanized steel plate with the yield strength of 280MPa is characterized in that a substrate comprises the following chemical components in percentage by weight: c: 0.0045-0.0085%, less than or equal to 0.050% of Si, Mn: 0.25-0.50%, P: 0.025-0.045%, S is less than or equal to 0.018%, Ti: 0.050-0.090%, B: 0.0003-0.0010%, N is less than or equal to 0.005%, Al: 0.015-0.060% of iron and inevitable impurities.
The metallographic structure of the hot-dip galvanized steel sheet is ferrite, the structure grain size grade is I7.5-9.5 grade, and the yield strength R of the hot-dip galvanized steel sheet with the thickness of 0.35-0.80 mmP0.2280 to 320MPa, tensile strength Rm340-400 Mpa, elongation after break A80mmIs 32 to 38 percent.
The reason why the chemical composition of the substrate of the cold-rolled hot-dip galvanized steel sheet with a yield strength of 280MPa is limited to the above range is as follows:
carbon: carbon is a solid solution strengthening element that increases the strength of the steel. When the carbon content in the steel is higher, the carbide content containing TI is increased, which is not beneficial to subsequent recrystallization; but the C content is controlled below 0.003 percent, the refining process is difficult to control, the decarburization time is long, the production cost is high, and the carbon content range is set to be 0.0045 to 0.0085 percent by comprehensive consideration;
silicon: silicon is taken as a solid solution strengthening element and has better strength when being dissolved in a steel plate matrixThe effect is changed; however, the invention must control the silicon content, and when the silicon content is higher, heavier Fe is formed on the surface of the hot rolled plate2O3And the acid cleaning is difficult to remove completely in the acid cleaning process, and the surface quality of a zinc coating is influenced during subsequent hot galvanizing, so that the plating leakage defect is caused, and therefore, Si is controlled to be less than or equal to 0.050 percent.
Manganese: manganese is used as a main element for solid solution strengthening, and proper manganese is added into steel, so that the strength is improved, the desulfurization is facilitated, and the hot brittleness of the steel can be avoided, therefore, the Mn content is limited to be 0.25-0.50%.
Sulfur: sulfur is a harmful element in steel; sulphur forms sulphide inclusions in the steel, reducing its ductility and toughness, and adds to the anisotropy of the steel; therefore, the S is controlled to be lower level as much as possible, and the invention limits the S to be less than or equal to 0.018 percent.
Phosphorus: phosphorus is an element with low price and strong solid solution strengthening capability, and the IF steel strength is increased and the elongation is reduced along with the increase of the phosphorus content; the over-high content of phosphorus can cause the brittleness of the material and influence the welding performance of the material, and can also accelerate the corrosion of a steel plate matrix at the grain boundary segregation, so that the problem of surface color difference caused by over-pickling is easily caused, thereby influencing the surface quality of subsequent galvanization. Accordingly, the present invention defines P as 0.025 to 0.045%.
Titanium: the invention further reduces the content of solid solution carbon nitrogen in the steel by microalloying titanium, thereby ensuring the non-timeliness of the steel plate, and in addition, the cost of titanium relative to niobium is lower, the form of sulfide can be changed, and the cold processing performance of the steel can be improved. However, the excessive Ti content increases the recrystallization temperature, and the Ti content is limited to 0.050% to 0.090% in the present invention.
Boron: according to the invention, trace boron is added, so that the segregation of phosphorus at a grain boundary can be inhibited, and the cold brittleness transition temperature of the phosphorus-containing IF steel can be obviously reduced, thereby reducing and eliminating the brittle fracture of subsequent secondary processing. The content of B is limited to 0.0003-0.0010%.
Nitrogen: nitrogen is a harmful element in the steel of the invention, and the nitrogen can seriously reduce the plasticity and toughness of the material, is sensitive to time efficiency, is not beneficial to the subsequent processing formability of the steel plate, and can reduce the addition amount of alloy titanium, so the nitrogen content is required to be limited. The invention limits N to be less than or equal to 0.005 percent.
Aluminum: aluminum acts as a strong deoxidizer, and forms Al with oxygen in steel2O3Removing the steel during steel making; and the bonding force with N is strong, and compound AlN is formed, so that the strain aging property of the steel is changed. However, too high aluminum will form too much Al2O3Inclusion and the continuous casting are easy to block the casting nozzle. The invention limits the Al content to be 0.015-0.060%.
A method for manufacturing a cold-rolled hot-dip galvanized steel sheet with 280 MPa-grade yield strength comprises the following steps:
continuously casting the molten steel subjected to vacuum decarburization and degassing treatment to obtain a continuous casting slab, wherein the molten steel comprises the following chemical components in percentage by weight: c: 0.0045-0.0085%, less than or equal to 0.050% of Si, Mn: 0.25-0.50%, P: 0.025-0.045%, S is less than or equal to 0.018%, Ti: 0.050-0.090%, B: 0.0003-0.0010%, N is less than or equal to 0.005%, Al: 0.015-0.060% of iron and inevitable impurities in balance;
heating the continuous casting plate blank to 1190-1240 ℃ by a heating furnace, and then carrying out hot rolling, wherein the hot rolling is a two-stage rolling process, the rough rolling is 5-pass continuous rolling, the rolling is carried out above the austenite recrystallization temperature, the finishing temperature of the rough rolling is 1030-1080 ℃, the thickness of an intermediate blank after the rough rolling is controlled to be 38-42mm, the finish rolling is 7-pass continuous rolling, the rolling is carried out in an austenite single-phase region, the finishing temperature of the finish rolling is 900-940 ℃, the finish rolling reduction rate is not less than 88%, the thickness of a steel plate after the finish rolling is 2.7-4.0 mm, the laminar cooling adopts front-section cooling, and the hot rolled steel coil is obtained when the coiling temperature;
and uncoiling the hot-rolled steel coil again, and then carrying out acid pickling, cold rolling, degreasing, annealing in a horizontal continuous annealing furnace, hot galvanizing and leveling to obtain a finished hot-galvanized steel plate with the thickness of 0.35-0.80 mm by coiling, wherein the cold rolling reduction is 75-90%, the temperature of the rolled hard strip steel in the annealing section of the horizontal continuous annealing furnace after cold rolling is 780-doped 810 ℃, the annealing time of the strip steel in the annealing section is 30-50s, and the leveling elongation is 0.6-1.2%.
The production process adopted by the invention has the following reasons:
1. setting of heating temperature of continuous casting slab
In order to ensure the finish rolling temperature, the hot rolling process is carried out in an austenite region, and the temperature of the continuous casting plate blank taken out of a heating furnace cannot be too low; the lower temperature of the furnace can prevent the second phase particles such as titanium compounds and the like from being dissolved and generate dispersed fine precipitates in the subsequent process, thereby not playing the role of improving the strength of the product; if the heating temperature of the plate blank is too high, thicker iron scale can be generated on the surface of the plate blank, and the plate blank is easy to press into the surface of the strip steel in the subsequent hot rolling rough rolling and finish rolling processes, so that the surface quality of a finished product is influenced. The heating temperature of the plate blank is set to be 1190-1240 ℃.
2. Roughing finish temperature and intermediate billet thickness setting
The rough rolling process needs to be controlled above the austenite recrystallization temperature for rolling. The finish temperature of rough rolling is too high, so that excessive secondary iron scale is easily formed, the finish rolling process is not easy to remove, and a landscape-shaped iron scale defect is formed on the surface of the steel plate after acid washing, so that the use of the surface of the steel plate and a user is influenced; if the rough rolling finishing temperature is too low, the finish rolling finishing temperature, namely rolling above the austenite recrystallization temperature, cannot be ensured, and the rough rolling finishing temperature is set to be 1030-1080 ℃.
The thickness of the intermediate billet affects the finish rolling temperature of the steel plate, if the thickness of the intermediate billet is too low, the temperature drop of the strip billet is too large, so that the subsequent finish rolling temperature is reduced, particularly the temperature drop of the edge of the steel plate is large, the steel plate can be rolled in an austenite and ferrite two-phase region, and the structure performance of the strip steel can be deteriorated. If the intermediate slab is too thick, the finish rolling load and rolling stability increase. The thickness of the intermediate blank is set to be 38-42 mm.
3. Finish rolling finish temperature setting
The finish rolling process of the invention needs to roll in an austenite single-phase region, and if the finish rolling temperature is too low, the finish rolling process can deteriorate the organization performance of the product when rolling in a ferrite and austenite two-phase region; if the finish rolling finishing temperature is set to be too high, not only is the production line difficult to reach, but also the iron scale on the surface of the steel plate is serious and is difficult to remove during acid cleaning, so that the surface quality is influenced; the finish rolling finishing temperature is set to be 900-940 ℃.
4. Setting of coiling temperature in Hot Rolling
If the hot rolling coiling temperature is too high, the recrystallized grains are easy to grow up and the yield strength is reduced during the subsequent cold rolling annealing; if the hot rolling coiling temperature is too low, the performance stability of the whole coil of the steel coil is influenced, and the second phase particles with smaller sizes are unfavorable for subsequent cold rolling annealing; the coiling temperature range set by the invention is 680-720 ℃.
5. Setting of laminar cooling mode after finish rolling
When finish rolling is completed, if the steel sheet is cooled at a low speed, i.e., by post-cooling, ferrite grains are coarse, and the yield strength is lowered. Therefore, the invention sets the laminar cooling mode after finish rolling to adopt front-stage cooling.
6. Cold rolling reduction setting
Due to the increase of the cold rolling deformation, the recrystallization of the subsequent annealing can be promoted, and a fine grain structure is obtained, so that the strength of the steel plate is improved; if the deformation is too high, the load of the rolling mill is too large, and the shape and the production stability of the strip steel are influenced; the cold rolling reduction rate is set to be 75-90%;
7. setting of annealing temperature and annealing time
In order to ensure that the galvanized product obtains higher yield strength, the grain size of recrystallization is controlled, the annealing temperature of continuous annealing is not high, and the annealing time can ensure that the recrystallization is finished. The temperature (annealing temperature) of the strip steel in the soaking section of the horizontal continuous annealing furnace is set to 780-810 ℃, and the annealing time of the strip steel in the soaking section of the horizontal continuous annealing furnace is set to 30-50s
8. Setting of the Flat elongation
The flattening can not only ensure the good plate shape of the strip steel, but also correspondingly improve the yield strength of the material through proper flattening rate, and the flattening elongation rate of the invention is 0.6-1.2%.
The metallographic structure of the hot-dip galvanized steel sheet produced by the method is ferrite, the structure grain size grade is I7.5-9.5 grade, and the yield strength R of the hot-dip galvanized steel sheet with the thickness of 0.35-0.80 mmP0.2280 to 320MPa, tensile strength Rm340-400 Mpa after breakingElongation A80mmIs 32 to 38 percent.
Compared with the prior art, the invention has the following positive effects: 1. the invention adopts the design of the components of the TI-IF steel containing phosphorus and the trace boron, and the matching design of hot rolling, acid rolling, annealing and flattening processes, so that the obtained final galvanized product has no timeliness, the surface and performance of the product, particularly the yield strength, meet the processing requirements of high-end household appliance users, and the manufacturing cost is lower. 2. By adding a proper amount of phosphorus, the strength of the product can be improved, and the problem of surface color difference caused by over-pickling is avoided; meanwhile, the micro-boron component design is adopted, and the micro-boron added into the steel can obviously reduce the cold brittleness transition temperature of the phosphorus-containing IF steel, so that the risk of brittle fracture of subsequent secondary processing of high-end household electrical appliance users is avoided. 3. The invention has lower manufacturing cost mainly embodied in that the noble alloy element of Nb is not needed to be added, and only the component design containing the phosphorus TI-IF is adopted; because the annealing temperature of the TI-IF steel is lower than that of the Nb-IF steel and the Nb-TI-IF steel, continuous annealing recrystallization can be completed at a lower temperature; meanwhile, the IF steel with slightly high carbon content is adopted for component design, so that the product strength is improved, and the requirements of RH refining technology and time can be reduced, thereby reducing the production cost.
Drawings
FIG. 1 is a photograph of a metallographic structure of a hot-dip galvanized steel sheet according to example 1 of the present invention.
Detailed Description
The present invention is further described with reference to examples 1 to 4, and as shown in tables 1 to 4, Table 1 shows the chemical compositions (in weight%) of the substrates of the hot-dip galvanized steel sheets according to examples of the present invention, and the balance Fe and inevitable impurities.
Table 1 chemical composition of substrate of hot dip galvanized steel sheet according to example of the present invention, unit: and (4) weight percentage.
According to the design requirements of the material components, molten steel meeting the requirements on chemical components is obtained by smelting in a converter, the molten steel is subjected to vacuum decarburization and degassing treatment in an RH furnace, the pure degassing time of the molten steel in the RH furnace is longer than 8 minutes, the molten steel is subjected to continuous casting under the protection of Ar blowing in the whole process to obtain a continuous casting slab, the thickness of the continuous casting slab is 210-230 mm, the width of the continuous casting slab is 900-1600 mm, and the length of the continuous casting slab is 8500-11000 mm.
And (3) sending the fixed-length plate blank produced in the steel-making process to a heating furnace for reheating, taking out the plate blank from the furnace for descaling, and sending the plate blank to a hot continuous rolling mill for rolling. The rolling is controlled by a rough rolling and finish rolling continuous rolling unit, the coiled steel is cooled by laminar flow, the laminar flow is cooled by a front section, a qualified hot rolled steel coil is produced, and the thickness of the hot rolled steel plate is 2.7-4.0 mm. The hot rolling process control parameters are shown in Table 2.
TABLE 2 Hot Rolling Process control parameters of the inventive examples
And uncoiling the hot-rolled steel coil again, then carrying out acid pickling, cold rolling, degreasing, annealing by a horizontal continuous annealing furnace, hot galvanizing and leveling, and coiling to obtain the hot-galvanized steel coil with the thickness of 0.35-0.80 mm. The degreasing adopts the conventional process, and the annealing process comprises the following steps: the temperature of the hot rolled hard strip steel after cold rolling in the annealing soaking section of the horizontal continuous annealing furnace is 780-810 ℃, the annealing time of the strip steel in the soaking section is 30-50s, and the flat elongation is 0.6-1.2%. The control parameters of the cold rolling, annealing and flattening processes are shown in Table 3.
TABLE 3 control parameters of the cold rolling, annealing and leveling processes of the examples of the present invention
Referring to fig. 1, the metallographic structure of the hot-dip galvanized steel sheet obtained by the method is ferrite, the grain size level of the structure is I7.5-9.5, and the yield strength R of the hot-dip galvanized steel sheetP0.2280 to 320MPa, tensile strength Rm340-400 Mpa after breakingElongation A80mmIs 32 to 38 percent.
The hot dip galvanized steel sheet obtained by the invention is subjected to a tensile test on a GB/T228.1-2010 metal material part 1: the mechanical properties of the hot-dip galvanized steel sheets are shown in Table 4.
TABLE 4 mechanical properties of hot-dip galvanized steel sheets according to examples of the present invention
From the properties in table 4, the hot-dip galvanized sheet of the invention has a suitable strength range, particularly yield strength and no aging index, and has good surface quality, thus completely meeting the processing requirements of high-end household electrical appliance users for manufacturing household electrical appliance panels.
In addition to the above embodiments, the present invention may have other embodiments. All technical solutions formed by adopting equivalent substitutions or equivalent transformations fall within the protection scope of the claims of the present invention.
Claims (4)
1. A cold-rolled hot-dip galvanized steel sheet with yield strength of 280MPa grade comprises the following chemical components in percentage by weight: c: 0.0045-0.0085%, less than or equal to 0.050% of Si, Mn: 0.25-0.50%, P: 0.025-0.045%, S is less than or equal to 0.018%, Ti: 0.050-0.090%, B: 0.0003-0.0010%, N is less than or equal to 0.005%, Al: 0.015-0.060% of iron and inevitable impurities in balance; the metallographic structure of the hot-dip galvanized steel sheet is ferrite, and the structure grain size grade is I7.5-9.5 grade.
2. The cold-rolled hot-dip galvanized steel sheet having a yield strength of 280MPa according to claim 1, wherein the yield strength R of the hot-dip galvanized steel sheet having a thickness of 0.35 to 0.80mmP0.2280 to 320MPa, tensile strength Rm340-400 Mpa, elongation after break A80mmIs 32 to 38 percent.
3. A method for manufacturing a cold-rolled hot-dip galvanized steel sheet with a yield strength of 280MPa is characterized by comprising the following steps:
continuously casting the molten steel subjected to vacuum decarburization and degassing treatment to obtain a continuous casting slab, wherein the molten steel comprises the following chemical components in percentage by weight: c: 0.0045-0.0085%, less than or equal to 0.050% of Si, Mn: 0.25-0.50%, P: 0.025-0.045%, S is less than or equal to 0.018%, Ti: 0.050-0.090%, B: 0.0003-0.0010%, N is less than or equal to 0.005%, Al: 0.015-0.060% of iron and inevitable impurities in balance;
heating the continuous casting plate blank to 1190-1240 ℃ by a heating furnace, and then carrying out hot rolling, wherein the hot rolling is a two-stage rolling process, the rough rolling is 5-pass continuous rolling, the rolling is carried out at the temperature above the austenite recrystallization temperature, the finishing temperature of the rough rolling is 1030-1080 ℃, the thickness of an intermediate blank after the rough rolling is controlled to be 38-42mm, the finish rolling is 7-pass continuous rolling, the rolling is carried out in an austenite single-phase region, the finishing temperature of the finish rolling is 900-940 ℃, the finish rolling reduction rate is not less than 88%, the laminar cooling after the finish rolling adopts front-section cooling, and a hot rolled steel coil is coiled when the coiling temperature is;
and uncoiling the hot-rolled steel coil again, and then carrying out acid pickling, cold rolling, degreasing, annealing in a horizontal continuous annealing furnace, hot galvanizing and leveling to obtain a finished hot-galvanized steel plate with the thickness of 0.35-0.80 mm by coiling, wherein the cold rolling reduction is 75-90%, the temperature of the rolled hard strip steel in the annealing section of the horizontal continuous annealing furnace after cold rolling is 780-doped 810 ℃, the annealing time of the strip steel in the annealing section is 30-50s, and the leveling elongation is 0.6-1.2%.
4. The method for producing a cold-rolled hot-dip galvanized steel sheet with a yield strength of 280MPa according to claim 3, wherein the thickness of the hot-rolled steel sheet after the hot-rolling finish rolling is controlled to be 2.7 to 4.0 mm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810659375.7A CN110629000A (en) | 2018-06-25 | 2018-06-25 | Cold-rolled hot-dip galvanized steel sheet with yield strength of 280MPa and manufacturing method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810659375.7A CN110629000A (en) | 2018-06-25 | 2018-06-25 | Cold-rolled hot-dip galvanized steel sheet with yield strength of 280MPa and manufacturing method thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN110629000A true CN110629000A (en) | 2019-12-31 |
Family
ID=68967982
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201810659375.7A Pending CN110629000A (en) | 2018-06-25 | 2018-06-25 | Cold-rolled hot-dip galvanized steel sheet with yield strength of 280MPa and manufacturing method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN110629000A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114395689A (en) * | 2021-12-09 | 2022-04-26 | 安阳钢铁集团有限责任公司 | Method for reducing yield platform |
| CN115491583A (en) * | 2021-06-18 | 2022-12-20 | 上海梅山钢铁股份有限公司 | Ultra-deep drawing cold rolling hot-dip aluminum-zinc steel plate and manufacturing method thereof |
| CN115505832A (en) * | 2021-06-07 | 2022-12-23 | 上海梅山钢铁股份有限公司 | Hot-dip aluminum-zinc steel plate for liquid crystal backboard with yield strength of 340MPa |
| CN117165845A (en) * | 2023-04-28 | 2023-12-05 | 鞍钢股份有限公司 | 340 MPa-level alloying hot dip galvanized sheet for new energy automobile and preparation method thereof |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102154586A (en) * | 2011-01-29 | 2011-08-17 | 首钢总公司 | Method for preventing surface of Ti-IF steel from forming crack defects |
| JP2011195946A (en) * | 2010-03-24 | 2011-10-06 | Jfe Steel Corp | High strength cold-rolled steel sheet excellent in surface appearance and having stable bh characteristic and method of producing the same |
| CN102644023A (en) * | 2012-04-23 | 2012-08-22 | 武汉钢铁(集团)公司 | Steel containing P and used for intermediate frequency (IF) automotive panel and production method thereof |
| CN102719740A (en) * | 2012-03-29 | 2012-10-10 | 鞍钢股份有限公司 | Method for producing ultra-low carbon high-strength cold rolling sheet |
| CN105112776A (en) * | 2015-08-25 | 2015-12-02 | 上海梅山钢铁股份有限公司 | Phosphorus-containing low-carbon cold-rolled hard tin-plated steel plate and production method thereof |
| KR101718469B1 (en) * | 2012-10-31 | 2017-03-21 | 제이에프이 스틸 가부시키가이샤 | Galvanized steel sheet |
| CN106854729A (en) * | 2015-12-09 | 2017-06-16 | 上海梅山钢铁股份有限公司 | A kind of phosphorous gap-free atom cold-rolling galvanization steel plate and its manufacture method |
-
2018
- 2018-06-25 CN CN201810659375.7A patent/CN110629000A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2011195946A (en) * | 2010-03-24 | 2011-10-06 | Jfe Steel Corp | High strength cold-rolled steel sheet excellent in surface appearance and having stable bh characteristic and method of producing the same |
| CN102154586A (en) * | 2011-01-29 | 2011-08-17 | 首钢总公司 | Method for preventing surface of Ti-IF steel from forming crack defects |
| CN102719740A (en) * | 2012-03-29 | 2012-10-10 | 鞍钢股份有限公司 | Method for producing ultra-low carbon high-strength cold rolling sheet |
| CN102644023A (en) * | 2012-04-23 | 2012-08-22 | 武汉钢铁(集团)公司 | Steel containing P and used for intermediate frequency (IF) automotive panel and production method thereof |
| KR101718469B1 (en) * | 2012-10-31 | 2017-03-21 | 제이에프이 스틸 가부시키가이샤 | Galvanized steel sheet |
| CN105112776A (en) * | 2015-08-25 | 2015-12-02 | 上海梅山钢铁股份有限公司 | Phosphorus-containing low-carbon cold-rolled hard tin-plated steel plate and production method thereof |
| CN106854729A (en) * | 2015-12-09 | 2017-06-16 | 上海梅山钢铁股份有限公司 | A kind of phosphorous gap-free atom cold-rolling galvanization steel plate and its manufacture method |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115505832A (en) * | 2021-06-07 | 2022-12-23 | 上海梅山钢铁股份有限公司 | Hot-dip aluminum-zinc steel plate for liquid crystal backboard with yield strength of 340MPa |
| CN115505832B (en) * | 2021-06-07 | 2023-09-05 | 上海梅山钢铁股份有限公司 | Hot-dip aluminum zinc-plated steel plate with yield strength of 340MPa for liquid crystal backboard |
| CN115491583A (en) * | 2021-06-18 | 2022-12-20 | 上海梅山钢铁股份有限公司 | Ultra-deep drawing cold rolling hot-dip aluminum-zinc steel plate and manufacturing method thereof |
| CN115491583B (en) * | 2021-06-18 | 2023-09-05 | 上海梅山钢铁股份有限公司 | Ultra-deep drawing cold-rolled hot-dip aluminum-zinc steel plate and manufacturing method thereof |
| CN114395689A (en) * | 2021-12-09 | 2022-04-26 | 安阳钢铁集团有限责任公司 | Method for reducing yield platform |
| CN117165845A (en) * | 2023-04-28 | 2023-12-05 | 鞍钢股份有限公司 | 340 MPa-level alloying hot dip galvanized sheet for new energy automobile and preparation method thereof |
| CN117165845B (en) * | 2023-04-28 | 2024-04-16 | 鞍钢股份有限公司 | 340 MPa-level alloying hot dip galvanized sheet for new energy automobile and preparation method thereof |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| KR101402365B1 (en) | Cold-rolled steel sheet having excellent slow-aging property and high curability in baking, and method for producing same | |
| CN113481430B (en) | 800 MPa-grade boron-containing hot-dip galvanized dual-phase steel with enhanced hole expansion performance and production method thereof | |
| JP2013133497A (en) | High-strength hot-rolled steel sheet excellent in stretch flange formability, and manufacturing method therefor | |
| CN110923550A (en) | Hot-rolled structural steel with high surface quality, high strength and toughness produced by adopting short process and production method | |
| CN110629000A (en) | Cold-rolled hot-dip galvanized steel sheet with yield strength of 280MPa and manufacturing method thereof | |
| CN110551939A (en) | Hot-dip galvanized steel plate with yield strength of 320MPa and production method thereof | |
| CN112553537A (en) | Cold-rolled hot-dip galvanized steel sheet with yield strength of 240MPa and manufacturing method thereof | |
| CN111690871B (en) | Hot-rolled steel plate for cold-rolled electro-galvanized steel plate and manufacturing method | |
| CN111961789A (en) | Structural-grade color-coated base material hot-dip galvanized steel plate for thin-specification steel products and manufacturing method thereof | |
| CN110527923B (en) | High-yield-ratio structural steel for 600 MPa-grade automobile body and production method thereof | |
| CN113584375B (en) | 600 MPa-grade low-manganese nickel-containing alloying hot-dip galvanized dual-phase steel with enhanced hole expansion performance and production method thereof | |
| CN114480972A (en) | Thin-specification Ni-free weathering steel produced based on CSP process and production method thereof | |
| CN111926252B (en) | Hot-rolled pickled steel plate for deep drawing and production method thereof | |
| JP2521553B2 (en) | Method for producing cold-rolled steel sheet for deep drawing having bake hardenability | |
| JP2001131692A (en) | High strength cold rolled steel sheet or high strength galvanized steel sheet excellent in surface property and press formability and producing method therefor | |
| CN113025882B (en) | Hot-base galvanized ferrite bainite high-strength steel plate and preparation method thereof | |
| CN111549285B (en) | Ultra-low carbon tin plate with excellent corrosion resistance and preparation method thereof | |
| CN113832392A (en) | Cold-rolled steel plate for enamel and production method thereof | |
| CN111926261A (en) | High-strength weathering steel with yield strength of 550MPa and production method thereof | |
| JP5919812B2 (en) | High strength thin steel sheet with excellent formability and method for producing the same | |
| CN111996456A (en) | Thick hot-dip galvanized steel with excellent bending property and production method thereof | |
| CN114207172A (en) | High-strength steel sheet, high-strength member, and method for producing same | |
| CN111041359A (en) | Economical hot-dip galvanized steel plate with excellent surface quality for photovoltaic bracket and production method thereof | |
| JP4890492B2 (en) | Method for producing alloyed hot-dip galvanized steel sheet with excellent paint bake hardening performance | |
| CN114427067A (en) | Cold-rolled hot-dip galvanized steel sheet with tensile strength of 300MPa and manufacturing method thereof |
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 | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20191231 |
|
| RJ01 | Rejection of invention patent application after publication |