CN111041327A - Production method of cold-rolled steel strip with yield strength below 210MPa - Google Patents
Production method of cold-rolled steel strip with yield strength below 210MPa Download PDFInfo
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- CN111041327A CN111041327A CN201911354673.6A CN201911354673A CN111041327A CN 111041327 A CN111041327 A CN 111041327A CN 201911354673 A CN201911354673 A CN 201911354673A CN 111041327 A CN111041327 A CN 111041327A
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C33/00—Making ferrous alloys
- C22C33/04—Making ferrous alloys by melting
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0205—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips of ferrous alloys
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- 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
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
- C21D8/0236—Cold rolling
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- 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
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
Abstract
The invention discloses a production method of a cold-rolled steel strip with yield strength below 210MPa, which comprises the following steps: selecting the chemical compositions and mass percentages of the manufactured steel strip: c: 0.008% -0.020%, Si: less than or equal to 0.015 percent, Mn: 0.10% -0.25%, P: less than or equal to 0.010 percent, S: less than or equal to 0.010 percent, Al: 0.015 to 0.045 percent, and the balance of Fe and inevitable impurities; producing a continuous casting slab through steelmaking, wherein the thickness of the continuous casting slab is 230mm, and after finishing, sending the continuous casting slab to a heating furnace, and then producing a cold rolling finished product coil with the thickness of 0.8 mm-1.0 mm through hot rolling, acid rolling and cold rolling; the invention produces the cold-rolled steel strip product with low yield strength for the flux-cored wire by adjusting and optimizing the parameters of steel-making, hot rolling, acid rolling and annealing processes; by adjusting and controlling the element content in the product, the adverse effect on the welding performance of the material is reduced, and the practicability of the product is improved.
Description
Technical Field
The invention relates to the technical field of metallurgy, in particular to a production method of a cold-rolled steel strip with yield strength below 210 MPa.
Background
The flux-cored wire is a welding wire material filled with a certain amount of medicinal powder, and compared with traditional shielded metal arc welding and submerged arc automatic welding, the flux-cored wire has the characteristics of stable, soft and low splashing electric arc, belongs to high and new technology products in the welding material industry, is widely applied to various departments such as shipbuilding, aerospace, machinery manufacturing, buildings, bridges, automobile manufacturing, marine industry and the like, and along with the continuous development of the flux-cored wire, the use of the flux-cored wire in Japan, Europe, America and other countries accounts for 20-40% of the proportion of the whole welding material, and has wide market prospect.
The flux-cored wire in China begins in the early 90 s of the 20 th century, and production methods are divided into a steel belt method, a wire coiling method and a steel pipe method according to different raw materials of the flux-cored wire. At present, the steel belt method for producing the flux-cored wire is widely applied. The flux-cored wire manufacturing material mainly comprises a cold-rolled steel strip and a filled flux core, wherein the mass of the cold-rolled steel strip accounts for 80-85% of the total mass of the flux-cored wire, the thickness of the steel strip is mainly concentrated at 0.8-1.0 mm, and the cold-rolled steel strip has high requirements on chemical components, thickness precision, surface quality, mechanical properties and the like.
With the development of economic construction in China, the demand of steel for the flux-cored wire in China is huge, and manufacturers capable of producing the product are gradually increased, but no corresponding industrial standard of cold-rolled steel strips for the flux-cored wire exists at present, the quality of the steel product for the flux-cored wire is required uniformly, so that users demand the steel product for the flux-cored wire in various ways, and the product types are relatively disordered. Aiming at the condition that the market has larger demand on the cold-rolled steel strip for the flux-cored wire with low strength level at present, in order to ensure the product quality and the stable supply quality and facilitate the correct material selection and application of customers, the production method of the cold-rolled steel strip for the flux-cored wire with the yield strength of below 210MPa is specially formulated.
Disclosure of Invention
Aiming at the problems in the prior art, the invention aims to provide a method for producing a cold-rolled steel strip with the yield strength of below 210 MPa.
The technical scheme adopted by the invention for solving the technical problems is as follows: a production method of a cold-rolled steel strip with yield strength below 210MPa comprises the following steps:
1) selecting the chemical compositions and mass percentages of the manufactured steel strip: c: 0.008% -0.020%, Si: less than or equal to 0.015 percent, Mn: 0.10% -0.25%, P: less than or equal to 0.010 percent, S: less than or equal to 0.010 percent, Al: 0.015 to 0.045 percent of the total weight of the alloy, and the balance of Fe, inevitable impurities and residual elements;
2) steel making: the molten steel is subjected to desulfurization, converter smelting and refining, and then is subjected to continuous casting to produce a continuous casting slab, wherein the thickness of the continuous casting slab is 230mm, the two sides of the slab are respectively subjected to peeling treatment for 3-4 mm, and the slab is sent to a heating furnace after finishing;
3) hot rolling: heating the plate blank by a heating furnace, hot rolling into a 1+5+7 three-stage rolling process, and producing a hot rolling raw material coil with the thickness specification of 3.5-5.0 mm by adopting a front-stage cooling mode in laminar cooling;
4) acid rolling: cooling the hot-rolled raw material coil to be less than or equal to 60 ℃, and producing a cold-hard coil with the thickness of 0.8-1.0 mm through re-uncoiling, acid washing, cold rolling and coiling;
5) cold rolling: and uncoiling, cleaning, annealing, flattening, trimming and coiling the cold-hard coil, wherein the annealing process adopts a continuous annealing process, the flattening machine adopts an elongation rate mode, and finally the cold-rolled finished coil with the thickness of 0.8-1.0 mm is produced.
Specifically, the heating furnace in the step 3 is heated to 1190-1230 ℃ and then is subjected to hot rolling, the hot rolling is a 1+5+7 three-stage rolling process, wherein a rough rolling R1 rolling mill is used for 1-pass rolling, a rough rolling R2 rolling mill is used for 5-pass reversible rolling, a finish rolling mill is used for 7-stand continuous rolling, and the finish rolling temperature is 870-910 ℃; and adopting a front section cooling mode for laminar cooling, wherein the coiling temperature is 700-730 ℃, and naturally cooling the hot rolled coil after coiling to produce the hot rolled raw material coil with the thickness specification of 3.5-5.0 mm.
Specifically, the cold rolling mill of the cold rolling process in the step 4 adopts a 5-stand six-roller continuous rolling unit, and the cold rolling reduction rate is 70-85%.
Specifically, the annealing process in the step 5 adopts a continuous annealing process, and specifically comprises a preheating section, a heating section, a soaking section, a slow cooling section, a fast cooling section, an overaging section, a final cooling section and a water quenching section, wherein the fuel is converter gas, the protective gas in the converter is NHx protective gas, and the annealing soaking temperature is 800-820 ℃.
Specifically, the leveler in the step 5 adopts an elongation percentage mode, the total elongation percentage is 0.7% -0.9%, and the roughness of the working roll of the leveler is 2.0-3.0 μm.
Specifically, the yield strength of the cold-rolled finished product coil with the thickness of 0.8-1.0 mm finally produced in the step 5 is less than or equal to 210MPa, the elongation after longitudinal fracture is more than or equal to 40 percent, the surface hardness is 30-50 HRB, and the surface roughness is 0.6-1.5 microns.
The invention has the following beneficial effects:
according to the production method of the cold-rolled steel strip with the yield strength of below 210MPa, the cold-rolled steel strip product for the flux-cored wire with low yield strength is produced by adjusting and optimizing parameters of steel making, hot rolling, acid rolling and annealing processes, and meanwhile, the cold-rolled steel strip product has high elongation, stable surface hardness index and good material forming performance, and meets the use requirements of most low-strength level flux-cored wire users in the market; by adjusting and controlling the contents of Si, Mn, P, S and Al elements in the product, the adverse effect on the welding performance of the material is reduced, the practicability of the product is improved, and the finished cold-rolled steel strip is more beneficial to the processing and use of a flux-cored wire terminal customer.
Detailed Description
The technical scheme in the embodiment of the invention is clearly and completely further detailed. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
A production method of a cold-rolled steel strip with yield strength below 210MPa comprises the following steps:
1) selecting the chemical compositions and mass percentages of the manufactured steel strip: c: 0.008% -0.020%, Si: less than or equal to 0.015 percent, Mn: 0.10% -0.25%, P: less than or equal to 0.010 percent, S: less than or equal to 0.010 percent, Al: 0.015 to 0.045 percent of the total weight of the alloy, and the balance of Fe, inevitable impurities and residual elements;
2) steel making: the molten steel is subjected to desulfurization, converter smelting and refining, and then is subjected to continuous casting to produce a continuous casting slab, wherein the thickness of the continuous casting slab is 230mm, the two sides of the slab are respectively subjected to peeling treatment for 3-4 mm, and the slab is sent to a heating furnace after finishing;
3) hot rolling: heating the plate blank to 1190-1230 ℃ by a heating furnace, and then carrying out hot rolling, wherein the hot rolling is a 1+5+7 three-stage rolling process, a rough rolling R1 rolling mill is used for 1-pass rolling, a rough rolling R2 rolling mill is used for 5-pass reversible rolling, a finish rolling mill is used for 7-stand continuous rolling, and the finish rolling temperature is 870-910 ℃; adopting a front-section cooling mode for laminar cooling, wherein the coiling temperature is 700-730 ℃, and naturally cooling the coiled hot-rolled coil to produce a hot-rolled raw material coil with the thickness specification of 3.5-5.0 mm;
4) acid rolling: cooling the hot-rolled raw material coil to be less than or equal to 60 ℃, and performing re-uncoiling, acid washing, cold rolling and coiling, wherein a cold rolling mill adopts a 5-frame six-roller continuous rolling unit, the cold rolling reduction rate is 70-85%, and cold and hard coils with the thickness of 0.8-1.0 mm are produced;
5) cold rolling: the cold-hard coil is uncoiled, cleaned, annealed, leveled, trimmed and coiled, wherein the annealing process adopts a continuous annealing process and specifically comprises a preheating section, a heating section, a soaking section, a slow cooling section, a fast cooling section, an overaging section, a final cooling section and a water quenching section, the fuel is converter gas, the protective gas in the furnace is NHx protective gas, and the annealing soaking temperature is 800-820 ℃; the leveler adopts an elongation percentage mode, the total elongation percentage is 0.7-0.9%, the roughness of the work roll of the leveler is 2.0-3.0 μm, and finally, a cold-rolled finished product coil with the thickness of 0.8-1.0 mm is produced.
The final cold rolled finished product coil with the thickness of 0.8 mm-1.0 mm has the yield strength of less than or equal to 210MPa, the elongation after longitudinal fracture of more than or equal to 40 percent, the surface hardness of 30 HRB-50 HRB and the surface roughness of 0.6 mu m-1.5 mu m.
In the production method of the cold-rolled steel strip for the flux-cored wire with the yield strength of below 210MPa, the continuous casting plate blank is set to be subjected to the skinning treatment in the step 2), the raw material inclusion is easy to cause the fracture of the drawing process because the steel strip for the flux-cored wire needs to be drawn and extended by a large deformation degree when being used by a user, and the skinning treatment of 3-4 mm on each side of the plate blank can effectively remove the inclusion layer on the surface of the plate blank and reduce the number of defects.
In the above production method, the heating temperature of the slab is set to be low in step 3, and in the cold-rolled steel strip product for flux-cored wire provided by the present invention, AlN is completely dissolved at a heating temperature of 1250 ℃, and the heating temperature of the slab is set not to be so high that AlN is not completely dissolved in austenite, so that AlN is further precipitated and coarsened using the existing precipitates as particles in subsequent hot rolling and coiling.
In the production method, the higher hot rolling finishing temperature is set in the step 3, so that the phenomenon of mixed crystals caused by entering a two-phase region for rolling in advance due to too low hot rolling finishing outlet temperature is avoided, a hot deformation texture is formed, and hot rolling deformation orientation is disordered and is favorable for annealing treatment. The design in step 3 is a front-section laminar cooling mode, and because the hot-rolled raw material for the flux-cored wire is thick in thickness specification, the plate shape control difficulty does not need to be considered too much, crystal grains can be refined by adopting front-section cooling after finish rolling, the strength is improved, the air cooling time of a high-temperature section is reduced, and the thickness of generated iron scales is reduced. The high hot rolling coiling temperature in the step 3 can make ferrite grains of the hot rolled strip steel coarse, carbides are coarsened due to aggregation, and second phase particles AlN are fully precipitated and grown, so that the ferrite grains can be grown large enough and the timeliness is reduced after the cold rolling and the continuous annealing in the step 4 and the step 5.
In the production method, the hot rolling raw material coil is required to be cooled to be less than or equal to 60 ℃ in the step 4, the equipment is prevented from being damaged due to overhigh temperature of the steel strip, and meanwhile, the risk that the transverse crease defect is aggravated due to overhigh temperature of the steel strip is avoided. The cold rolling process of the cold-rolled steel strip product for the flux-cored wire provided by the invention has the key point that a high reduction is ensured under a good lubricating condition to generate a strong favorable deformation texture and create conditions for generating an ideal recrystallization annealing texture by the next annealing step.
In the production method, the higher annealing temperature is set in the step 5, so that ferrite grains can be ensured to grow fully, and the lower yield strength performance is ensured. The flattening elongation in the step 5 is set to be 0.7-0.9%, the yield platform of a cold-rolled finished product can be eliminated, the timeliness of the product is reduced, and meanwhile, the good surface quality of the steel strip is guaranteed. And 5, setting the roughness of the working roll of the temper mill to be 2.0-3.0 microns, and ensuring higher surface roughness and good surface microcosmic characteristics of a cold-rolled finished product so as to be beneficial to rolling and drawing of a steel strip, improve the wire drawing speed, improve the product practicability and reduce the user cost.
Example 1
A furnace of molten steel with chemical components meeting the requirements is obtained after KR desulfurization, converter smelting and RH refining, and the specific components are shown in Table 1. And continuously casting the molten steel to produce a plate blank, wherein the thickness of the plate blank is 230mm, and the two sides of the plate blank are respectively subjected to 3mm peeling treatment.
And (2) conveying the continuous casting plate blank to a hot rolling heating furnace for charging and heating, wherein the heating temperature is 1225 ℃, discharging the plate blank, carrying out 1+5+ 7-pass rolling by a rough rolling double-rack R1+ R2 rolling mill and a finish rolling seven-rack continuous rolling unit, automatically calculating pass reduction rate by a model, wherein the finish rolling temperature is 880 ℃, adopting front-section cooling for laminar cooling, and finally entering a hot rolling coiler at 710 ℃ to produce a hot rolling coil with the thickness of 4.0 mm.
And naturally cooling the hot rolled coil to 45 ℃, uncoiling the coil again, carrying out continuous cold rolling on the coil in a five-rack six-roller cold continuous rolling mill once after acid pickling, wherein the total rolling reduction of the cold rolling is 80.0%, the rolling reduction of each rack is automatically calculated by a model, and the cold-rolled coil is coiled to obtain a cold-hard coil with the thickness of 0.8 mm.
The cold-hard coil is uncoiled again, cleaned, annealed and leveled, wherein the annealing adopts a continuous annealing process, the annealing soaking temperature is 805 ℃, the leveling elongation is 0.7 percent, the roughness of a working roll of a leveling machine is 2.5 mu m, and the cold-rolled finished coil with the thickness of 0.8mm is obtained through preheating, heating, soaking, slow cooling, fast cooling, overaging, final cooling and water quenching.
The cold-rolled steel strip for the flux-cored wire obtained by the method has the yield strength of 202MPa, the elongation A50 after longitudinal fracture of 45 percent, the surface hardness of 40HRB and the surface roughness of 0.9 mu m. The specific properties are shown in Table 2.
Example 2
A furnace of molten steel with chemical components meeting the requirements is obtained after KR desulfurization, converter smelting and RH refining, and the specific components are shown in Table 1. And continuously casting the molten steel to produce a plate blank, wherein the thickness of the plate blank is 230mm, and the two sides of the plate blank are respectively subjected to 3mm peeling treatment.
And (2) conveying the continuous casting plate blank to a hot rolling heating furnace for charging and heating, wherein the heating temperature is 1210 ℃, discharging the plate blank from the furnace, carrying out '1 +5+ 7' pass rolling by a rough rolling double-rack R1+ R2 rolling mill and a finish rolling seven-rack continuous rolling unit, automatically calculating pass reduction rate by a model, carrying out finish rolling at 890 ℃, carrying out laminar cooling by adopting front-section cooling, and finally, entering a hot rolling coiler at 715 ℃ to produce a hot rolling coil with the thickness of 4.2 mm.
And naturally cooling the hot rolled coil to 35 ℃, uncoiling the coil again, carrying out continuous cold rolling on the coil in a five-rack six-roller cold continuous rolling mill once after acid pickling, wherein the total rolling reduction of the cold rolling is 78.6%, the rolling reduction of each rack is automatically calculated by a model, and the cold-rolled coil is coiled to obtain a cold-hard coil with the thickness of 0.9 mm.
And the cold-hard coil is uncoiled again, cleaned, annealed and leveled, wherein the annealing process adopts a continuous annealing process, the annealing soaking temperature is 815 ℃, the leveling elongation is 0.8 percent, the roughness of a working roll of a leveling machine is 2.5 mu m, and the cold-rolled finished coil with the thickness of 0.9mm is obtained through preheating, heating, soaking, slow cooling, fast cooling, overaging, final cooling and water quenching.
The cold-rolled steel strip for the flux-cored wire obtained by the method has the yield strength of 189MPa, the longitudinal post-fracture elongation A50 of 48 percent, the surface hardness of 36HRB and the surface roughness of 1.1 mu m. The specific properties are shown in Table 2.
Example 3
And (3) obtaining a furnace of molten steel with required chemical components after KR desulfurization, converter smelting and LF refining, wherein the specific components are shown in Table 1. And continuously casting the molten steel to produce a plate blank, wherein the thickness of the plate blank is 230mm, and the two sides of the plate blank are respectively subjected to 4mm peeling treatment.
And (2) conveying the continuous casting plate blank to a hot rolling heating furnace for charging and heating, wherein the heating temperature is 1200 ℃, discharging the plate blank, carrying out 1+5+ 7-pass rolling through a rough rolling double-rack R1+ R2 rolling mill and a finish rolling seven-rack continuous rolling unit, automatically calculating pass reduction rate by a model, wherein the finish rolling temperature is 900 ℃, adopting front-section cooling for laminar cooling, and finally entering a hot rolling coiler at 720 ℃ to produce a hot rolling coil with the thickness of 4.5 mm.
And naturally cooling the hot rolled coil to 52 ℃, uncoiling the coil again, carrying out continuous cold rolling on the coil in a five-rack six-roller cold continuous rolling mill once after acid pickling, wherein the total rolling reduction of the cold rolling is 77.8 percent, the rolling reduction of each rack is automatically calculated by a model, and the cold-rolled coil is coiled to obtain a cold-hard coil with the thickness of 1.0 mm.
The cold-hard coil is uncoiled again, cleaned, annealed and leveled, wherein the annealing adopts a continuous annealing process, the annealing soaking temperature is 815 ℃, the leveling elongation is 0.9 percent, the roughness of a working roll of a leveling machine is 3.0 mu m, and the cold-rolled finished coil with the thickness of 1.0mm is obtained through preheating, heating, soaking, slow cooling, fast cooling, overaging, final cooling and water quenching.
The cold-rolled steel strip for the flux-cored wire obtained by the method has the yield strength of 196MPa, the elongation A50 after longitudinal fracture of 47 percent, the surface hardness of 38HRB and the surface roughness of 1.4 mu m. The specific properties are shown in Table 2.
TABLE 1 Main chemical composition Table of molten steel in examples 1 to 3
| Element/%) | C | Si | Mn | P | S | Al |
| The invention | 0.008～0.020 | ≤0.015 | 0.10～0.25 | ≤0.010 | ≤0.010 | 0.015～0.045 |
| Example 1 | 0.020 | 0.010 | 0.18 | 0.008 | 0.007 | 0.021 |
| Example 2 | 0.010 | 0.008 | 0.16 | 0.010 | 0.008 | 0.035 |
| Example 3 | 0.016 | 0.009 | 0.20 | 0.007 | 0.005 | 0.040 |
TABLE 2 Performance of the finished steel strip in examples 1-3
The present invention is not limited to the above embodiments, and any structural changes made under the teaching of the present invention shall fall within the scope of the present invention, which is similar or similar to the technical solutions of the present invention.
The techniques, shapes, and configurations not described in detail in the present invention are all known techniques.
Claims (6)
1. A production method of a cold-rolled steel strip with yield strength below 210MPa is characterized by comprising the following steps:
1) selecting the chemical compositions and mass percentages of the manufactured steel strip: c: 0.008% -0.020%, Si: less than or equal to 0.015 percent, Mn: 0.10% -0.25%, P: less than or equal to 0.010 percent, S: less than or equal to 0.010 percent, Al: 0.015 to 0.045 percent of the total weight of the alloy, and the balance of Fe, inevitable impurities and residual elements;
2) steel making: the molten steel is subjected to desulfurization, converter smelting and refining, and then is subjected to continuous casting to produce a continuous casting slab, wherein the thickness of the continuous casting slab is 230mm, the two sides of the slab are respectively subjected to peeling treatment for 3-4 mm, and the slab is sent to a heating furnace after finishing;
3) hot rolling: heating the plate blank by a heating furnace, hot rolling into a 1+5+7 three-stage rolling process, and producing a hot rolling raw material coil with the thickness specification of 3.5-5.0 mm by adopting a front-stage cooling mode in laminar cooling;
4) acid rolling: cooling the hot-rolled raw material coil to be less than or equal to 60 ℃, and producing a cold-hard coil with the thickness of 0.8-1.0 mm through re-uncoiling, acid washing, cold rolling and coiling;
5) cold rolling: and uncoiling, cleaning, annealing, flattening, trimming and coiling the cold-hard coil, wherein the annealing process adopts a continuous annealing process, the flattening machine adopts an elongation rate mode, and finally the cold-rolled finished coil with the thickness of 0.8-1.0 mm is produced.
2. The method for producing the cold-rolled steel strip with the yield strength of below 210MPa according to claim 1, wherein the heating furnace in the step 3 is heated to 1190-1230 ℃ and then is subjected to hot rolling, and the hot rolling is a three-stage rolling process of "1 +5+ 7", wherein a rough rolling R1 rolling mill is used for 1-pass rolling, a rough rolling R2 rolling mill is used for 5-pass reversible rolling, a finish rolling mill is used for 7-stand continuous rolling, and the finish rolling temperature is 870-910 ℃; and adopting a front section cooling mode for laminar cooling, wherein the coiling temperature is 700-730 ℃, and naturally cooling the hot rolled coil after coiling to produce the hot rolled raw material coil with the thickness specification of 3.5-5.0 mm.
3. The method for producing the cold-rolled steel strip with the yield strength of below 210MPa according to claim 1, wherein the cold rolling mill in the cold rolling process in the step 4 adopts a 5-stand six-roll continuous rolling mill train, and the cold rolling reduction rate is 70-85%.
4. The method for producing the cold-rolled steel strip with the yield strength of below 210MPa according to claim 1, wherein the annealing process in the step 5 adopts a continuous annealing process, and specifically comprises a preheating section, a heating section, a soaking section, a slow cooling section, a fast cooling section, an overaging section, a final cooling section and a water quenching section, wherein the fuel is converter gas, the protective gas in the furnace is NHx protective gas, and the annealing soaking temperature is 800-820 ℃.
5. The method of producing a cold-rolled steel strip with a yield strength of 210MPa or less as claimed in claim 1, wherein the temper mill in step 5 is in an elongation mode, the total elongation is 0.7-0.9%, and the temper mill work roll roughness is 2.0-3.0 μm.
6. The method for producing a cold-rolled steel strip with a yield strength of 210MPa or less according to claim 1, wherein the yield strength of the final cold-rolled finished coil with a thickness of 0.8mm to 1.0mm in the step 5 is 210MPa or less, the elongation after longitudinal fracture is 40% or more, the surface hardness is 30HRB to 50HRB, and the surface roughness is 0.6 μm to 1.5 μm.
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| CN201911354673.6A CN111041327A (en) | 2019-12-25 | 2019-12-25 | Production method of cold-rolled steel strip with yield strength below 210MPa |
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| CN201911354673.6A Pending CN111041327A (en) | 2019-12-25 | 2019-12-25 | Production method of cold-rolled steel strip with yield strength below 210MPa |
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| CN111961833A (en) * | 2020-07-14 | 2020-11-20 | 柳州钢铁股份有限公司 | Manufacturing method of continuous-annealing SPCC steel strip with performance close to that of cover annealing product and continuous-annealing SPCC steel strip |
| CN112359285A (en) * | 2020-11-09 | 2021-02-12 | 山东钢铁集团日照有限公司 | Ageing-resistant cold-rolled continuously annealed steel strip and manufacturing method thereof |
| CN112899562A (en) * | 2021-01-15 | 2021-06-04 | 山东钢铁集团日照有限公司 | Micro-carbon hot-dip galvanized steel strip with stable yield strength control and production method thereof |
| CN113699340A (en) * | 2021-07-30 | 2021-11-26 | 安阳钢铁集团有限责任公司 | Method for eliminating yield platform of continuous annealing of thin low-carbon steel of 0.3-0.9mm |
| CN113699442A (en) * | 2021-08-02 | 2021-11-26 | 山东钢铁集团日照有限公司 | Cold-rolled steel strip for boron-added structure and production method thereof |
| CN113714288A (en) * | 2021-08-19 | 2021-11-30 | 安钢集团冷轧有限责任公司 | Production method of hot-rolled strip steel for low-cost low-yield-strength DC01 cold-rolled sheet |
| CN114433624A (en) * | 2022-01-21 | 2022-05-06 | 甘肃酒钢集团宏兴钢铁股份有限公司 | Frosted surface stainless steel cold rolling production method |
| CN114959476A (en) * | 2022-05-27 | 2022-08-30 | 山东钢铁集团日照有限公司 | Economical cold-rolled steel strip for flux-cored wire and production method thereof |
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| CN113714288A (en) * | 2021-08-19 | 2021-11-30 | 安钢集团冷轧有限责任公司 | Production method of hot-rolled strip steel for low-cost low-yield-strength DC01 cold-rolled sheet |
| CN114433624A (en) * | 2022-01-21 | 2022-05-06 | 甘肃酒钢集团宏兴钢铁股份有限公司 | Frosted surface stainless steel cold rolling production method |
| CN114959476A (en) * | 2022-05-27 | 2022-08-30 | 山东钢铁集团日照有限公司 | Economical cold-rolled steel strip for flux-cored wire and production method thereof |
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Application publication date: 20200421 |