CN112030075A - 700 MPa-level automobile girder steel with stable impact toughness and production method thereof - Google Patents
700 MPa-level automobile girder steel with stable impact toughness and production method thereof Download PDFInfo
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
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- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
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- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0221—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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- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
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- C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
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- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/12—Ferrous alloys, e.g. steel alloys containing tungsten, tantalum, molybdenum, vanadium, or niobium
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- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
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- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/14—Ferrous alloys, e.g. steel alloys containing titanium or zirconium
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/004—Dispersions; Precipitations
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/005—Ferrite
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Abstract
700 MPa-grade automobile girder steel with stable impact toughness and a production method thereof belong to the technical field of metallurgy. The automobile girder steel comprises the following chemical components in percentage by mass: 0.06-0.09%, Si: 0.05 to 0.25%, Mn: 1.30-1.80%, P is less than or equal to 0.02%, S is less than or equal to 0.005%, Nb: 0.02-0.08%, Ti: 0.07-0.12%, Als: 0.01-0.04%, N is less than or equal to 0.005%, and the balance is Fe and inevitable impurities. The production method comprises converter smelting, LF + RH refining, continuous casting, heating, rough rolling, finish rolling and laminar cooling; and (3) rolling by adopting an empty rolling mill, fully opening cooling water between the racks, wherein the water quantity is 50-80%, and the threading speed is 2.2-2.6 m/s. The automobile girder steel-20 ℃ full-size sample has 150-180J impact energy and stable impact toughness.
Description
Technical Field
The invention belongs to the technical field of metallurgy, and particularly relates to 700 MPa-grade automobile girder steel with stable impact toughness and a production method thereof.
Background
With the development of the light weight trend of the automobile industry, more and more enterprises select girder steel with high strength and stable performance to replace the original steel grade with low strength. The automobile frame is used as an important part of a truck, almost bears all the weight of the automobile and goods, and directly influences the driving safety of the automobile. The automobile beam steel is generally formed by a punch forming process, and the deformation mode of the automobile beam steel is mainly bending, so the beam steel has to have enough strength and toughness, good fatigue resistance and cold formability.
Chinese patent application with publication number CN 110331344A discloses automobile beam steel with stable strength performance and Rm more than or equal to 600MPa and a production method thereof. The metallographic structure of the automobile frame steel is ferrite and pearlite; the fluctuation range of the tensile strength between steel coils is not more than 120MPa, the fluctuation range of the yield strength is not more than 100MPa, the fluctuation of the elongation A is not more than 0.6% up and down at 23%, and the fluctuation of the yield ratio is not more than 0.02 up and down at 0.88. But the heating temperature of the plate blank is higher, so that the fuel consumption of the heating furnace is high, and meanwhile, the strength grade of the automobile beam steel is lower, and the impact toughness is not clearly required, so that the possibility of unqualified impact toughness exists in the use process of the automobile beam steel, and certain economic loss is caused to enterprises.
Although the performance of 700MPa automobile girder steel produced by the prior art meets the standard requirements, the impact toughness fluctuation is over 100J, the impact toughness stability is insufficient, and the normal production of enterprises is seriously influenced. With the gradual and wide application of the thick 700MPa grade girder steel, the use requirement is increased particularly in a low-temperature environment, and the development of the thick 700MPa grade automobile girder steel with stable impact toughness is imperative.
Disclosure of Invention
In order to solve the technical problems, the invention provides 700 MPa-grade automobile girder steel with stable impact toughness and a production method thereof. The automobile beam steel has low production cost, high strength, high toughness, small fluctuation of impact toughness and stable performance. The invention adopts the following technical scheme:
the 700 MPa-grade automobile girder steel with stable impact toughness comprises the following chemical components in percentage by mass: 0.06-0.09%, Si: 0.05 to 0.25%, Mn: 1.30-1.80%, P is less than or equal to 0.02%, S is less than or equal to 0.005%, Nb: 0.02-0.08%, Ti: 0.07-0.12%, Als: 0.01-0.04%, N is less than or equal to 0.005%, and the balance is Fe and inevitable impurities.
The thickness of the automobile beam steel is 12.0-16.0 mm, the metallographic structure of the automobile beam steel is quasi-polygonal ferrite, acicular ferrite and TiC educt, and the grain size is 11.5-13.0 grade.
The automobile beam steel has yield strength of 660-740 MPa, tensile strength of 740-820 MPa, elongation of 18-24% and yield ratio of 0.89-0.92, and the impact energy of a full-size sample at-20 ℃ is 150-180J.
The production method of the 700 MPa-grade automobile beam steel with stable impact toughness comprises converter smelting, LF + RH refining, continuous casting and hot rolling.
The hot rolling process comprises the steps of heating a plate blank, rough rolling, finish rolling and laminar cooling. The temperature of the plate blank in a heating furnace is 600-750 ℃, the discharging temperature is 1210-1270 ℃, and the in-furnace time is 180-300 min; 3+5 passes of rough rolling are adopted; the thickness of the intermediate billet is 50-55 mm, the finish rolling inlet temperature is 950-1000 ℃, an empty rolling mill is adopted for rolling, cooling water between racks is fully opened, the water amount is controlled to be 50-80%, the threading speed is 2.2-2.6 m/s, and the finish rolling temperature is 820-860 ℃; the laminar cooling adopts front section concentrated cooling, the cooling water temperature is 25-33 ℃, the cooling speed is 15-30 ℃/s, and the coiling temperature is 570-610 ℃.
The finish rolling procedure of the invention adopts a hollow rolling mill for rolling, and mainly aims to increase the reduction rate of a single stand, enable precipitates to be dispersed and fine, induce impact fractures to form high-density small-size dimples and stabilize the impact toughness of the material. Meanwhile, the cooling water quantity between the racks is increased, the rolling speed is improved, the recovery time of the strip steel at high temperature is shortened, the deformation and dense nucleation are facilitated, the crystal grains are refined, and the mixed crystal structure is reduced.
The plate blank can be directly loaded into the furnace in the heating process, the charging temperature is 600-750 ℃, and the combustion consumption of the heating furnace is reduced by the high charging temperature; the rolling power consumption can be saved by using one rolling process, and the effect of reducing the cost is achieved.
The automobile girder steel produced by the method has the yield strength of 660-740 MPa, the tensile strength of 740-810 MPa, the elongation of 18-24%, the yield ratio of 0.89-0.92, the impact energy of a full-size sample at-20 ℃ of 150-180J, and stable impact toughness, and completely meets the requirements of automobile manufacturing enterprises.
Drawings
FIG. 1 is a microstructure diagram of an automotive girder steel of example 1;
FIG. 2 is a microstructure diagram of an automotive girder steel of example 2;
FIG. 3 is a microstructure diagram of the automobile girder steel of example 3.
Detailed Description
The present invention will be described in further detail with reference to examples.
Example 1
The thickness of the 700MPa grade automobile beam steel with stable impact toughness of the embodiment is 12.0mm, and the chemical composition and the mass percentage content are shown in Table 1. The production method comprises the working procedures of converter smelting, LF + RH refining, continuous casting, slab heating, rolling, laminar cooling and slow cooling. The method comprises the following specific steps:
the charging temperature of the plate blank is 680 ℃, the heating time is 240min, and the discharging temperature of the plate blank is 1240 ℃. The rolling is controlled in two stages, the first stage is rough rolling, 3+5 passes of rolling are adopted, and the thickness of an intermediate billet is 51 mm; the second stage is finish rolling, wherein the inlet temperature of finish rolling is 995 ℃, the finished product passes through an F1-F7 finishing mill group, the finished product is rolled by one rolling mill in an empty state, cooling water between the finishing mill frames is fully boiled, the water content is 60%, the threading speed is 2.6m/s, and the finish rolling temperature of the finish rolling is 846 ℃. The laminar cooling stage adopts a front section centralized cooling mode, the cooling water temperature is 28 ℃, the cooling speed is 23 ℃/s, and the coiling temperature is 580 ℃.
The automobile beam steel of the embodiment has the following mechanical properties: the yield strength is 685MPa, the tensile strength is 750MPa, the elongation is 20%, the yield ratio is 0.91, the bending test is qualified, and the impact energy of a full-size sample at the temperature of-20 ℃ is 164J; the microstructure of the steel coil is shown in figure 1, and the metallographic structure of the steel coil is quasi-polygonal ferrite, acicular ferrite and TiC precipitate, so that the mixed crystal phenomenon is avoided, and the grain size is 12.0 grade as shown in figure 1.
Example 2
The thickness of the 700MPa grade automobile beam steel with stable impact toughness of the embodiment is 14.0mm, and the chemical composition and the mass percentage content are shown in Table 1. The production method comprises the working procedures of converter smelting, LF + RH refining, continuous casting, slab heating, rolling, laminar cooling and slow cooling. The method comprises the following specific steps:
the charging temperature of the plate blank is 650 ℃, the heating time is 185min, and the discharging temperature of the plate blank is 1243 ℃. The rolling is controlled in two stages, the first stage is rough rolling, 3+5 passes of rolling are adopted, and the thickness of an intermediate billet is 51 mm; the second stage is finish rolling, the inlet temperature of the finish rolling is 989 ℃, the steel strip passes through an F1-F7 finishing mill group, the steel strip is rolled by one rolling mill in an empty state, cooling water between finishing mill frames is fully boiled, the water content is 70%, the threading speed is 2.4m/s, and the finish rolling temperature of the finish rolling is 837 ℃. The laminar cooling stage adopts a front section centralized cooling mode, the cooling water temperature is 28 ℃, the cooling speed is 22 ℃/s, and the coiling temperature is 601 ℃.
The automobile beam steel of the embodiment has the following mechanical properties: the yield strength is 740MPa, the tensile strength is 810MPa, the elongation is 20 percent, the yield ratio is 0.91, the bending test is qualified, and the impact energy of a full-size test sample at the temperature of minus 20 ℃ is 172J; the microstructure of the steel coil is shown in figure 2, and the metallographic structure is quasi-polygonal ferrite, acicular ferrite and TiC precipitates which are known from figure 2, the mixed crystal phenomenon is avoided, and the grain size is 12.0 grade.
Example 3
The thickness of the 700MPa grade automobile beam steel with stable impact toughness of the embodiment is 16.0mm, and the chemical composition and the mass percentage content are shown in Table 1. The production method comprises the working procedures of converter smelting, LF + RH refining, continuous casting, slab heating, rolling, laminar cooling and slow cooling. The method comprises the following specific steps:
the charging temperature of the plate blank is 660 ℃, the heating time is 239min, and the discharging temperature of the plate blank is 1244 ℃. The rolling is controlled in two stages, the first stage is rough rolling, the 3+5 times of rolling is adopted, and the thickness of an intermediate billet is 55 mm; the second stage is finish rolling, the inlet temperature of the finish rolling is 984 ℃, the steel strip passes through an F1-F7 finishing mill group, the steel strip is rolled by one rolling mill in an empty mode, cooling water between finishing mill frames is fully boiled, the water content is 80%, the threading speed is 2.2m/s, and the finish rolling temperature of the finish rolling is 841 ℃. The laminar cooling stage adopts a front section centralized cooling mode, the cooling water temperature is 28 ℃, the cooling speed is 19 ℃/s, and the coiling temperature is 595 ℃.
The automobile beam steel of the embodiment has the following mechanical properties: the yield strength is 691MPa, the tensile strength is 765MPa, the elongation is 22.5 percent, the yield ratio is 0.90, the bending test is qualified, and the impact energy of a full-size test sample at the temperature of minus 20 ℃ is 180J; the microstructure of the steel coil is shown in figure 3, and the metallographic structure is quasi-polygonal ferrite, acicular ferrite and TiC precipitate, no mixed crystal phenomenon exists and the grain size is 11.5 grade according to the figure 3.
Example 4
The thickness of the 700MPa grade automobile beam steel with stable impact toughness of the embodiment is 15.1mm, and the chemical component composition and the mass percentage content are shown in Table 1. The production method comprises the working procedures of converter smelting, LF + RH refining, continuous casting, slab heating, rolling, laminar cooling and slow cooling. The method comprises the following specific steps:
the charging temperature of the plate blank is 611 ℃, the heating time is 180min, and the discharging temperature of the plate blank is 1265 ℃. The rolling is controlled in two stages, the first stage is rough rolling, the 3+5 passes of rolling are adopted, and the thickness of an intermediate billet is 54 mm; the second stage is finish rolling, the inlet temperature of the finish rolling is 950 ℃, the steel strip passes through an F1-F7 finishing mill group, the steel strip is rolled by one rolling mill in an empty way, the cooling water between the finishing mill groups is fully boiled, the water content is 75%, the threading speed is 2.3m/s, and the finish rolling temperature of the finish rolling is 830 ℃. The laminar cooling stage adopts a front section centralized cooling mode, the cooling water temperature is 25 ℃, the cooling speed is 25 ℃/s, and the coiling temperature is 602 ℃.
The automobile beam steel of the embodiment has the following mechanical properties: the yield strength is 670MPa, the tensile strength is 748MPa, the elongation is 21 percent, the yield ratio is 0.90, the bending test is qualified, and the impact energy of a full-size test sample at the temperature of minus 20 ℃ is 165J; the metallographic structure of the steel coil is a quasi-polygonal ferrite, an acicular ferrite and a TiC precipitate, the phenomenon of mixed crystals is avoided, and the grain size is 12.0 grade.
Example 5
The thickness of the 700MPa grade automobile beam steel with stable impact toughness of the embodiment is 12.4mm, and the chemical composition and the mass percentage content are shown in Table 1. The production method comprises the working procedures of converter smelting, LF + RH refining, continuous casting, slab heating, rolling, laminar cooling and slow cooling. The method comprises the following specific steps:
the charging temperature of the plate blank is 750 ℃, the heating time is 202min, and the discharging temperature of the plate blank is 1217 ℃. The rolling is controlled in two stages, the first stage is rough rolling, 3+5 passes of rolling are adopted, and the thickness of an intermediate billet is 50 mm; the second stage is finish rolling, the inlet temperature of the finish rolling is 961 ℃, the steel strip passes through an F1-F7 finishing mill group, the steel strip is rolled by one rolling mill in an empty state, cooling water between finishing mill frames is fully boiled, the water content is 50%, the threading speed is 2.6m/s, and the finish rolling temperature of the finish rolling is 860 ℃. The laminar cooling stage adopts a front section centralized cooling mode, the cooling water temperature is 31 ℃, the cooling speed is 17 ℃/s, and the coiling temperature is 590 ℃.
The automobile beam steel of the embodiment has the following mechanical properties: the yield strength is 682MPa, the tensile strength is 740MPa, the elongation is 24 percent, the yield ratio is 0.92, the bending test is qualified, and the impact energy of a full-size test sample at the temperature of minus 20 ℃ is 178J; the metallographic structure of the steel coil is a quasi-polygonal ferrite, an acicular ferrite and a TiC precipitate, the phenomenon of mixed crystals is avoided, and the grain size is 13.0 grade.
Example 6
The thickness of the 700MPa grade automobile beam steel with stable impact toughness of the embodiment is 14.5mm, and the chemical composition and the mass percentage content are shown in Table 1. The production method comprises the working procedures of converter smelting, LF + RH refining, continuous casting, slab heating, rolling, laminar cooling and slow cooling. The method comprises the following specific steps:
the charging temperature of the plate blank is 704 ℃, the heating time is 265min, and the discharging temperature of the plate blank is 1210 ℃. The rolling is controlled in two stages, the first stage is rough rolling, the 3+5 passes of rolling are adopted, and the thickness of an intermediate billet is 52 mm; the second stage is finish rolling, the inlet temperature of the finish rolling is 976 ℃, the steel is rolled by one rolling mill after passing through an F1-F7 finishing mill group, the cooling water between the finishing mill groups is fully boiled, the water content is 70%, the threading speed is 2.4m/s, and the finish rolling temperature of the finish rolling is 842 ℃. The laminar cooling stage adopts a front section centralized cooling mode, the cooling water temperature is 29 ℃, the cooling speed is 15 ℃/s, and the coiling temperature is 603 ℃.
The automobile beam steel of the embodiment has the following mechanical properties: yield strength 692MPa, tensile strength 749MPa, elongation 22%, yield ratio 0.92, bending test qualification, and impact energy 158J of full-size sample at-20 ℃; the metallographic structure of the steel coil is a quasi-polygonal ferrite, an acicular ferrite and a TiC precipitate, the phenomenon of mixed crystals is avoided, and the grain size is 12.5 grade.
Example 7
The thickness of the 700MPa grade automobile beam steel with stable impact toughness of the embodiment is 13.8mm, and the chemical composition and the mass percentage content are shown in Table 1. The production method comprises the working procedures of converter smelting, LF + RH refining, continuous casting, slab heating, rolling, laminar cooling and slow cooling. The method comprises the following specific steps:
the charging temperature of the plate blank is 600 ℃, the heating time is 219min, and the discharging temperature of the plate blank is 1270 ℃. The rolling is controlled in two stages, the first stage is rough rolling, 3+5 passes of rolling are adopted, and the thickness of an intermediate billet is 51 mm; the second stage is finish rolling, the inlet temperature of the finish rolling is 955 ℃, the steel strip passes through an F1-F7 finishing mill group, the steel strip is rolled by one mill in an empty way, the cooling water between the finishing mill groups is fully boiled, the water content is 65%, the threading speed is 2.5m/s, and the finish rolling temperature of the finish rolling is 820 ℃. The laminar cooling stage adopts a front section centralized cooling mode, the cooling water temperature is 30 ℃, the cooling speed is 20 ℃/s, and the coiling temperature is 610 ℃.
The automobile beam steel of the embodiment has the following mechanical properties: the yield strength is 660MPa, the tensile strength is 743MPa, the elongation is 23.5 percent, the yield ratio is 0.89, the bending test is qualified, and the impact energy of a full-size test sample at the temperature of minus 20 ℃ is 175J; the metallographic structure of the steel coil is a quasi-polygonal ferrite, an acicular ferrite and a TiC precipitate, the phenomenon of mixed crystals is avoided, and the grain size is 12.0 grade.
Example 8
The thickness of the 700MPa grade automobile beam steel with stable impact toughness of the embodiment is 15.6mm, and the chemical component composition and the mass percentage content are shown in Table 1. The production method comprises the working procedures of converter smelting, LF + RH refining, continuous casting, slab heating, rolling, laminar cooling and slow cooling. The method comprises the following specific steps:
the charging temperature of the plate blank is 736 ℃, the heating time is 283min, and the discharging temperature of the plate blank is 1256 ℃. The rolling is controlled in two stages, the first stage is rough rolling, the 3+5 passes of rolling are adopted, and the thickness of an intermediate billet is 54 mm; the second stage is finish rolling, the inlet temperature of the finish rolling is 1000 ℃, the steel strip passes through an F1-F7 finishing mill group, the steel strip is rolled by one rolling mill in an empty way, the cooling water between the finishing mill frames is fully boiled, the water content is 75%, the threading speed is 2.2m/s, and the finish rolling temperature is 833 ℃. The laminar cooling stage adopts a front section concentrated cooling mode, the cooling water temperature is 26 ℃, the cooling speed is 30 ℃/s, and the coiling temperature is 592 ℃.
The automobile beam steel of the embodiment has the following mechanical properties: the yield strength is 715MPa, the tensile strength is 795MPa, the elongation is 18 percent, the yield ratio is 0.90, the bending test is qualified, and the impact energy of a full-size test sample at the temperature of minus 20 ℃ is 150J; the metallographic structure of the steel coil is a quasi-polygonal ferrite, an acicular ferrite and a TiC precipitate, the phenomenon of mixed crystals is avoided, and the grain size is 11.5 grade.
Example 9
The thickness of the 700MPa grade automobile beam steel with stable impact toughness of the embodiment is 13.2mm, and the chemical component composition and the mass percentage content are shown in Table 1. The production method comprises the working procedures of converter smelting, LF + RH refining, continuous casting, slab heating, rolling, laminar cooling and slow cooling. The method comprises the following specific steps:
the charging temperature of the plate blank is 628 ℃, the heating time is 300min, and the discharging temperature of the plate blank is 1229 ℃. The rolling is controlled in two stages, the first stage is rough rolling, 3+5 passes of rolling are adopted, and the thickness of an intermediate billet is 51 mm; the second stage is finish rolling, the inlet temperature of the finish rolling is 969 ℃, the steel strip passes through an F1-F7 finishing mill group, the steel strip is rolled by one rolling mill in an empty state, the cooling water between the finishing mill frames is fully boiled, the water content is 65%, the threading speed is 2.5m/s, and the finish rolling temperature of the finish rolling is 850 ℃. The laminar cooling stage adopts a front section centralized cooling mode, the cooling water temperature is 33 ℃, the cooling speed is 28 ℃/s, and the coiling temperature is 570 ℃.
The automobile beam steel of the embodiment has the following mechanical properties: the yield strength is 731MPa, the tensile strength is 820MPa, the elongation is 19 percent, the yield ratio is 0.89, the bending test is qualified, and the impact energy of a full-size test sample at the temperature of minus 20 ℃ is 155J; the metallographic structure of the steel coil is a quasi-polygonal ferrite, an acicular ferrite and a TiC precipitate, the phenomenon of mixed crystals is avoided, and the grain size is 12.0 grade.
Table 1. automobile girder steel of each example has chemical components and mass percentage (%)
Claims (8)
1. The 700 MPa-grade automobile girder steel with stable impact toughness is characterized by comprising the following chemical components in percentage by mass: 0.06-0.09%, Si: 0.05 to 0.25%, Mn: 1.30-1.80%, P is less than or equal to 0.02%, S is less than or equal to 0.005%, Nb: 0.02-0.08%, Ti: 0.07-0.12%, Als: 0.01-0.04%, N is less than or equal to 0.005%, and the balance is Fe and inevitable impurities.
2. The automobile girder steel with stable impact toughness and 700MPa level according to claim 1, wherein the thickness of the automobile girder steel is 12.0-16.0 mm.
3. The automobile girder steel with stable impact toughness and grade 700MPa according to claim 2, wherein the automobile girder steel has a metallographic structure of quasi-polygonal ferrite, acicular ferrite and TiC precipitates, and the grain size is 11.5-13.0 grade.
4. The automobile girder steel with stable impact toughness and 700MPa level according to claim 3, is characterized in that the automobile girder steel has yield strength of 660-740 MPa, tensile strength of 740-820 MPa, elongation of 18-24%, yield ratio of 0.89-0.92 and impact energy of 150-180J of a full-size sample at-20 ℃.
5. The method for producing the 700 MPa-grade automotive frame steel with stable impact toughness according to any one of claims 1 to 4, characterized in that the production method comprises converter smelting, LF + RH refining, continuous casting and hot rolling; the hot rolling process comprises the steps of heating a plate blank, rough rolling, finish rolling and laminar cooling, wherein the rough rolling adopts 3+5 times of rolling; and (3) rolling by using an empty rolling mill, fully opening cooling water between the racks, controlling the water quantity to be 50-80% and threading speed to be 2.2-2.6 m/s.
6. The method for producing 700MPa grade automobile beam steel with stable impact toughness according to claim 5, wherein in the hot rolling process, the temperature of a plate blank in a heating furnace is 600-750 ℃, the tapping temperature is 1210-1270 ℃, and the furnace time is 180-300 min.
7. The method for producing 700MPa grade automobile beam steel with stable impact toughness according to claim 6, wherein in the hot rolling process, the thickness of an intermediate billet is 50-55 mm, the inlet temperature of finish rolling is 950-1000 ℃, and the finish rolling temperature is 820-860 ℃.
8. The method for producing 700MPa grade automotive frame steel with stable impact toughness according to any one of claims 5 to 7, characterized in that the hot rolling process adopts front-stage concentrated cooling for laminar cooling, the cooling water temperature is 25-33 ℃, the cooling speed is 15-30 ℃/s, and the coiling temperature is 570-610 ℃.
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114231836A (en) * | 2021-11-11 | 2022-03-25 | 邯郸钢铁集团有限责任公司 | 700L steel strip with stable performance and excellent toughness and production method thereof |
| CN114480973A (en) * | 2022-01-28 | 2022-05-13 | 本钢板材股份有限公司 | Ultra-wide specification 800 MPa-level hot-rolled girder steel and production process thereof |
| CN115572903A (en) * | 2022-10-14 | 2023-01-06 | 山东钢铁集团日照有限公司 | Low-cost, low-temperature-impact and high-toughness steel for automobile structures and production method thereof |
| CN115627417A (en) * | 2022-10-14 | 2023-01-20 | 山东钢铁集团日照有限公司 | Economic high-strength high-toughness 700MPa grade girder steel and production method thereof |
| CN115652055A (en) * | 2022-12-14 | 2023-01-31 | 江苏省沙钢钢铁研究院有限公司 | Hot-rolled steel plate and production method thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN114231836A (en) * | 2021-11-11 | 2022-03-25 | 邯郸钢铁集团有限责任公司 | 700L steel strip with stable performance and excellent toughness and production method thereof |
| CN114480973A (en) * | 2022-01-28 | 2022-05-13 | 本钢板材股份有限公司 | Ultra-wide specification 800 MPa-level hot-rolled girder steel and production process thereof |
| CN115572903A (en) * | 2022-10-14 | 2023-01-06 | 山东钢铁集团日照有限公司 | Low-cost, low-temperature-impact and high-toughness steel for automobile structures and production method thereof |
| CN115627417A (en) * | 2022-10-14 | 2023-01-20 | 山东钢铁集团日照有限公司 | Economic high-strength high-toughness 700MPa grade girder steel and production method thereof |
| CN115652055A (en) * | 2022-12-14 | 2023-01-31 | 江苏省沙钢钢铁研究院有限公司 | Hot-rolled steel plate and production method thereof |
| CN115652055B (en) * | 2022-12-14 | 2023-03-28 | 江苏省沙钢钢铁研究院有限公司 | Hot-rolled steel plate and production method thereof |
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