CN117165872B - Single titanium microalloyed corrosion-resistant high-strength steel with high hole expansion rate - Google Patents
Single titanium microalloyed corrosion-resistant high-strength steel with high hole expansion rate Download PDFInfo
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- 238000005260 corrosion Methods 0.000 title claims abstract description 57
- 230000007797 corrosion Effects 0.000 title claims abstract description 57
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- 229910052698 phosphorus Inorganic materials 0.000 claims abstract description 30
- 239000012535 impurity Substances 0.000 claims abstract description 24
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- 238000005096 rolling process Methods 0.000 claims description 130
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 76
- 238000000034 method Methods 0.000 claims description 67
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- 238000010079 rubber tapping Methods 0.000 claims description 44
- 238000009749 continuous casting Methods 0.000 claims description 39
- 238000001816 cooling Methods 0.000 claims description 31
- 238000007711 solidification Methods 0.000 claims description 31
- 230000008023 solidification Effects 0.000 claims description 31
- 229910052742 iron Inorganic materials 0.000 claims description 30
- 238000002788 crimping Methods 0.000 claims description 22
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 18
- 229910052782 aluminium Inorganic materials 0.000 claims description 18
- 238000007664 blowing Methods 0.000 claims description 18
- 238000002360 preparation method Methods 0.000 claims description 17
- 238000003756 stirring Methods 0.000 claims description 17
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- 238000005728 strengthening Methods 0.000 description 6
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Classifications
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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
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Abstract
The application provides a single titanium microalloyed corrosion-resistant high-strength steel with high hole expansion rate, and relates to the field of metallurgy. The single-titanium microalloyed corrosion-resistant high-strength steel with high hole expansion rate comprises the following components: c:0.06% -0.07%, mn:1.1% -1.5%, ti:0.09% -0.10%, alt:0.026% -0.03%, cr:0.015% -0.020%, cu:0.016% -0.022%, ni:0.024-0.027%, N:0.001% -0.003%, S:0-0.005%, P:0-0.003%, and the balance of Fe and unavoidable impurity elements. The single-titanium microalloyed corrosion-resistant high-strength steel with high hole expansion rate has high strength and toughness, has higher hole expansion rate, replaces the conventional component design of adding Nb element and Ti element in a composite way to improve the strength, and reduces the cost.
Description
Technical Field
The application relates to the field of metallurgy, in particular to a single-titanium microalloyed corrosion-resistant high-strength steel with high hole expansion rate.
Background
Automobile body weight reduction has become the mainstream direction of automobile technical development nowadays, and the requirements on the safety of the structure are higher and higher. Reaming is a common structural failure mode, and can lead to the reduction of strength and rigidity of the structure, so that the reaming performance of the microalloy steel is improved, the reaming resistance of the structure can be enhanced, and the safety is ensured. In addition, steel is susceptible to corrosion in corrosive environments, which reduces its useful life. By improving the corrosion resistance of the steel, the service life of the steel in a severe environment can be prolonged, and the replacement and maintenance cost can be reduced.
At present, the common means is to improve the comprehensive performance of the material by Nb and Ti composite microalloying, thereby meeting the use requirements of customers. However, by adopting the Nb and Ti microalloying process, the design performance and cost of the product are excessive, and the cost is high.
Patent document CN110643783A discloses 780 MPa-grade high-surface high-performance stability ultrahigh-reaming steel and a manufacturing method thereof, wherein the ultrahigh-reaming steel has good structural uniformity, performance uniformity and excellent strength, plasticity and ultrahigh-reaming rate matching, the yield strength is more than or equal to 750MPa, the tensile strength is more than or equal to 780MPa, the reaming rate is more than or equal to 70%, the requirements of users can be well met, the ultrahigh-surface high-performance stability ultrahigh-reaming steel can be applied to parts, such as control arms, auxiliary frames and the like, of chassis parts of passenger vehicles, but the steel only reaches 780 MPa-grade strength, has lower elongation, does not have good corrosion resistance, and limits the application scene of the steel.
Patent document CN111235477B discloses 950MPa thin hot rolled automobile girder steel and a preparation method thereof, and the patent document successfully develops the 950MPa thin high-strength hot rolled girder steel by adding Nb element and Ti element and matching with corresponding rolling and cooling processes, so that the weight of a automobile body can be further reduced, but Nb element resources are scarce, so that the cost is higher, and the resources are consumed.
Disclosure of Invention
The invention aims to provide single-titanium microalloyed corrosion-resistant high-strength steel with high hole expansion rate so as to solve the problems.
In order to achieve the above purpose, the present application adopts the following technical scheme:
the single-titanium microalloyed corrosion-resistant high-strength steel with high hole expansion rate comprises the following components in percentage by mass:
c:0.06% -0.07%, mn:1.1% -1.5%, ti:0.09% -0.10%, alt:0.026% -0.03%, cr:0.015% -0.020%, cu:0.016% -0.022%, ni:0.024-0.027%, N:0.001% -0.003%, S:0-0.005%, P:0-0.003%, and the balance of Fe and unavoidable impurity elements;
the preparation method comprises the following steps:
sequentially carrying out converter smelting, LF refining, RH refining, continuous casting, soaking treatment, rolling and crimping on the raw materials to obtain the high-expansion-ratio single-titanium microalloyed corrosion-resistant high-strength steel;
the superheat degree of continuous casting is controlled to be 15-20 ℃, and the soaking temperature is 1240-1260 ℃; the rolling comprises rough rolling and finish rolling, wherein the temperature of the rough rolling is 1010-1060 ℃, the inlet temperature of the finish rolling is 1060-1070 ℃, the finishing temperature is 875-885 ℃, and the air cooling speed is 11.9-13.5 ℃/s; the temperature of the crimping is 600-610 ℃.
Preferably, the molten iron smelted by the converter is pretreated, and the P content is controlled to be not higher than 0.002%.
Preferably, 0.33-0.37kg/t molten steel of aluminum block is added in the converter smelting process.
Preferably, the converter smelting controls tapping components, the S content is not higher than 0.005%, and the P content is not higher than 0.003%.
Preferably, the LF refining ensures that the steel composition reaches C:0.06% -0.07%, mn:1.1% -1.5%, ti:0.09% -0.10%, alt:0.026% -0.03%, cr:0.015% -0.020%, cu:0.016% -0.022%, ni:0.024-0.027%.
Preferably, the vacuum degree of the RH refining is not higher than 100Pa, and the time of the RH refining is 15-20min.
Preferably, the titanium-containing cored wire is added in the RH refining process, and soft blowing is performed after the titanium-containing cored wire is added, wherein the soft blowing time is 10-20min.
Preferably, the solidification end of the continuous casting adopts electromagnetic stirring, and the parameter is (7-10) HZ/400A.
Preferably, the soaking treatment is carried out for 60-70min.
Preferably, the rough rolling is performed in 4 to 5 passes and the finish rolling is performed in 5 to 7 passes.
Compared with the prior art, the beneficial effects of this application include:
the single-titanium microalloyed corrosion-resistant high-strength steel with high hole expansion rate, provided by the application, aims at the problems of high cost of microalloyed steel and low hole expansion performance of steel, develops the single-titanium microalloyed corrosion-resistant high-strength steel with high hole expansion rate and the production process thereof, and truly depends on a pure Ti microalloying technology to produce high-strength Ti microalloyed high-strength steel in batches. The Ti microalloying is adopted to produce the high-strength steel, so that the cost is saved, the hole expansion rate of the steel is improved, and the problem of light weight in automobile manufacturing is solved. In addition, the method of Ti, ni, cu, cr cooperative regulation and control is adopted to produce the high-strength corrosion-resistant steel, so that the steel has higher strength and simultaneously ensures the corrosion resistance of the high-strength steel. The RH refining furnace is adopted to remove impurities in steel, so that the purity of the steel is improved, the hot rolled plate is directly curled at 600-610 ℃, grains can be effectively refined, the performance of the steel is improved, processing steps and equipment can be reduced, and the production cost is reduced.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the embodiments will be briefly described below, it being understood that the following drawings only illustrate certain embodiments of the present application and therefore should not be considered as limiting the scope of the present application.
FIG. 1 is a photograph showing the morphology of the structure, crystal grains, precipitated phases, intragranular and grain boundary dislocations in the high strength steel obtained in example 1;
FIG. 2 is a photograph of the morphology of grains in the high-strength steel obtained in comparative example 1;
FIG. 3 is a photograph showing the morphology of inclusions in the high-strength steel obtained in comparative example 2;
FIG. 4 is a photograph showing the structure morphology of the high-strength steel obtained in comparative example 7.
Detailed Description
Firstly, the technical scheme provided by the application is integrally introduced, and the method is as follows:
the single-titanium microalloyed corrosion-resistant high-strength steel with high hole expansion rate comprises the following components in percentage by mass:
c:0.06% -0.07%, mn:1.1% -1.5%, ti:0.09% -0.10%, alt:0.026% -0.03%, cr:0.015% -0.020%, cu:0.016% -0.022%, ni:0.024-0.027%, N:0.001% -0.003%, S:0-0.005%, P:0-0.003%, and the balance of Fe and unavoidable impurity elements;
the preparation method comprises the following steps:
sequentially carrying out converter smelting, LF refining, RH refining, continuous casting, soaking treatment, rolling and crimping on the raw materials to obtain the high-expansion-ratio single-titanium microalloyed corrosion-resistant high-strength steel;
The superheat degree of continuous casting is controlled to be 15-20 ℃, and the soaking temperature is 1240-1260 ℃; the rolling comprises rough rolling and finish rolling, wherein the temperature of the rough rolling is 1010-1060 ℃, the inlet temperature of the finish rolling is 1060-1070 ℃, the finishing temperature is 875-885 ℃, and the air cooling speed is 11.9-13.5 ℃/s; the temperature of the crimping is 600-610 ℃.
Optionally, in the high-expansion-ratio single-titanium microalloyed corrosion-resistant high-strength steel, the content of C can be any value between 0.060%, 0.061%, 0.062%, 0.063%, 0.064%, 0.065%, 0.066%, 0.067%, 0.068%, 0.069%, 0.070% or 0.06% -0.07% calculated by mass percent; the Mn content may be any value between 1.1, 1.2%, 1.3%, 1.4%, 1.5% or 1.1% -1.5%; the Ti content may be any value between 0.090%, 0.091%, 0.092%, 0.093%, 0.094%, 0.095%, 0.096%, 0.097%, 0.098%, 0.099%, 0.10%, or 0.09% -0.10%; the content of Alt may be any value between 0.026, 0.027, 0.028, 0.029, 0.03, or 0.026% -0.03%; the Cr content may be any value between 0.015%, 0.016%, 0.017%, 0.018%, 0.019%, 0.020% or 0.015% to 0.020%; the Cu content may be any value between 0.016%, 0.017%, 0.018%, 0.019%, 0.020%, 0.021%, 0.022% or 0.016% -0.022%; the Ni content may be 0.024%, 0.025%, 0.026%, 0.027%, or any value between 0.024-0.027%; the content of N may be any value between 0.001%, 0.002%, 0.003% or 0.001% -0.003%; the content of S may be any value between 0%, 0.001%, 0.002%, 0.003%, 0.004%, 0.005% or 0-0.005%; the content of P may be any value between 0%, 0.001%, 0.002%, 0.003% or 0-0.003%.
The superheat degree of continuous casting can be controlled to be any value between 15 ℃, 16 ℃, 17 ℃, 18 ℃, 19 ℃, 20 ℃ or 15-20 ℃, and the soaking temperature can be any value between 1240 ℃, 1250 ℃, 1260 ℃ or 1240-1260 ℃; the rolling comprises rough rolling and finish rolling, the temperature of the rough rolling can be any value between 1010 ℃, 1020 ℃, 1030 ℃, 1040 ℃, 1050 ℃, 1060 ℃ or 1010-1060 ℃, the inlet temperature of the finish rolling can be any value between 1060 ℃, 1065 ℃, 1070 ℃ or 1060-1070 ℃, the final rolling temperature can be any value between 875 ℃, 880 ℃, 885 ℃ or 875-885 ℃, and the air cooling speed can be any value between 11.9 ℃/s, 12.0 ℃/s, 12.5 ℃/s, 13.0 ℃/s, 13.5 ℃/s or 11.9-13.5 ℃/s; the temperature of the crimp may be 600 ℃, 605 ℃, 610 ℃, or any value between 600-610 ℃.
The corresponding actions of the elements are as follows:
c: carbon can increase the strength and hardness of steel by solid solution strengthening and precipitation hardening, and improve the tensile strength and yield strength. The addition of an appropriate amount of carbon can increase the strength and hardness of the steel, but an excessive amount of carbon can lead to an increase in brittleness.
Mn: manganese can form solid solution with a steel matrix, so that the steel is effectively reinforced, and the tensile strength and the yield strength of the steel are improved. Too high or too low a manganese content may have an adverse effect. Too high a manganese content may cause an increase in brittleness of the steel, and too low a manganese content may cause a decrease in toughness and plasticity of the steel.
Ti: the addition of titanium can refine grains and improve the strength of grain boundaries. The fine grains and the strong grain boundaries can resist the formation and expansion of the reamed holes, thereby reducing the hole expansion ratio of the steel. The combined action of titanium and nickel can further increase the toughness of the steel, thereby improving the reaming formation and expansion behavior. In addition, the combined action of titanium and copper can also improve the strength and corrosion resistance of the steel, and further improve the reaming and forming performance.
Alt: the addition of aluminum can refine grains and improve the strength of grain boundaries.
Cr: the addition of chromium can improve the corrosion resistance of the steel and form a stable chromium oxide layer. The improvement of corrosion resistance can slow down the reaming rate in corrosive media and improve the reaming and forming performances of steel. When the chromium content exceeds a certain range, excessive chromium may not be completely dissolved in the steel matrix, resulting in an increase in the precipitation phase of chromium. These precipitated phases may affect the uniformity and structural stability of the steel, reducing the strength and toughness, hole expansion properties, and corrosion resistance of the steel. In addition, when the chromium content is low, the effect of improving the corrosion resistance of the steel cannot be achieved.
Cu: the addition of copper can improve the strength and hardness of the steel, and can also improve the corrosion resistance of the steel. These characteristics can improve the hole-forming properties of the steel and slow down the formation and expansion of the hole. Excessive copper reduces the strength and toughness of the steel. The addition of copper causes instability of the lattice structure and makes the steel more brittle, thereby reducing its tensile strength and impact toughness. Copper can improve the corrosion resistance of steel within a certain range. It can form stable oxide film to prevent steel from being corroded. If the copper content is insufficient, a sufficient oxide film may not be formed, resulting in a decrease in corrosion resistance of the steel.
Ni: the addition of nickel can improve the toughness and ductility of the steel, especially at low temperatures. The toughness can be improved, the reaming caused by impact load can be resisted, and the reaming forming performance of the steel is improved. If the nickel content is too low, the strengthening effect of nickel may not be sufficiently exhibited, resulting in a decrease in the strength and toughness of the steel. Nickel can improve the corrosion resistance of the steel within a certain range. It can form stable passive film to prevent steel from being corroded. If the nickel content is too low, a sufficient passivation film may not be formed, resulting in a decrease in corrosion resistance of the steel.
N: the nitrogen can form solid solution with the steel matrix, so that the steel is effectively reinforced, and the tensile strength and the yield strength are improved. However, tiN generated by the combination of Ti element and N in steel may reduce the impact toughness of the steel.
S: s is an unavoidable impurity element in steel, and the content should be as low as possible. In addition, S and Mn in steel are liable to form MnS inclusions, and sulfide inclusions in the rolling direction cause an increase in anisotropy of the steel sheet, deteriorating toughness and plasticity of the steel. During the smelting process, the S content should be as low as possible.
P: p is an unavoidable impurity element in steel, which reduces toughness, plasticity and weldability of the steel, so that the weld joint is cold-friable, the content is as low as possible, but too low causes the increase of smelting cost.
In an alternative embodiment, the molten iron smelted by the converter is pretreated, and the P content is controlled to be not higher than 0.002%.
And the residual element conditions of molten iron and molten steel are noted before and during production, so that the standard requirements are met.
In an alternative embodiment, 0.33-0.37kg/t molten steel of aluminum block is added in the converter smelting process.
Generally, the composition is adjusted as appropriate according to the tapping C and the refining and entering conditions.
Optionally, the amount of the aluminum block added in the converter smelting process can be any value between 0.33kg/t molten steel, 0.34kg/t molten steel, 0.35kg/t molten steel, 0.36kg/t molten steel, 0.37kg/t molten steel or 0.33-0.37kg/t molten steel.
In an alternative embodiment, the converter smelting controls the tapping composition such that the S content is not higher than 0.005% and the P content is not higher than 0.003%.
And slag blocking and tapping are carried out, so that the slag blocking effect is ensured.
In an alternative embodiment, the LF refining ensures that the steel composition reaches C:0.06% -0.07%, mn:1.1% -1.5%, ti:0.09% -0.10%, alt:0.026% -0.03%, cr:0.015% -0.020%, cu:0.016% -0.022%, ni:0.024-0.027%.
When the alloy is added, the charging temperature should be controlled so as to avoid the adverse effect of severe temperature change on the temperature balance in the furnace and the smelting process.
In an alternative embodiment, the RH refining vacuum is not higher than 100Pa, and the RH refining time is 15-20min.
In an alternative embodiment, the titanium-containing cored wire is added in the RH refining process, and soft blowing is performed after the titanium-containing cored wire is added, wherein the soft blowing time is 10-20min.
RH refining can remove impurities in steel, and the uniformity and purity of the steel can be improved by RH refining, so that the toughness of the steel is further improved.
In an alternative embodiment, the solidification end of the continuous casting is electromagnetic stirring with parameters of (7-10) HZ/400A.
The solidification end adopts electromagnetic stirring, so that the convection movement of molten steel is enhanced, the degree of superheat is eliminated, the solidification structure of a casting blank is improved, and the segregation of elements is controlled.
In an alternative embodiment, the soaking time is 60-70 minutes.
In an alternative embodiment, the rough rolling is performed in 4-5 passes and the finish rolling is performed in 5-7 passes.
Taking 7 passes of finish rolling as an example, the finish rolling reduction control is generally controlled within the range shown in the following table 1:
TABLE 1 finish rolling reduction ranges
Embodiments of the present application will be described in detail below with reference to specific examples, but it will be understood by those skilled in the art that the following examples are only for illustration of the present application and should not be construed as limiting the scope of the present application.
Example 1
The embodiment provides a single titanium microalloyed corrosion-resistant high-strength steel with high hole expansion rate, which comprises the following main components in percentage by weight: c:0.06%, mn:1.2%, ti:0.10%, alt:0.027%, cr:0.017%, cu:0.018%, ni:0.027%, N:0.001%, S:0.003%, P:0.002%, and the balance of Fe and unavoidable impurity elements.
The preparation process of the single titanium microalloyed corrosion-resistant high-strength steel with high hole expansion rate comprises the following steps: the high-strength steel is prepared by adopting converter smelting, LF refining, RH refining, continuous casting, heating, rolling and crimping.
Smelting in a converter: pretreatment of molten iron, P:0.002%. And the residual element conditions of molten iron and molten steel are noted before and during production, so that the standard requirements are met. Aluminum block: 0.33kg/t molten steel, and adjusted as appropriate according to tapping C and refining incoming components. Controlling tapping components: s:0.003%, P:0.002%. And slag blocking and tapping are carried out, so that the slag blocking effect is ensured.
LF: the target components and the actual conditions in the smelting process are adjusted to ensure that the chemical components of the steel meet the requirements: c:0.06%, mn:1.2%, alt:0.027%, cr:0.017%, cu:0.018%, ni:0.027%. When the alloy is added, the charging temperature should be controlled so as to avoid the adverse effect of severe temperature change on the temperature balance in the furnace and the smelting process.
RH refining: vacuum (less than or equal to 100 Pa) time: 15min; and after the molten pool is stable, adding the titanium-containing cored wire. Soft blowing time after adding titanium-containing cored wire: 15min.
Continuous casting: the whole process of protection pouring is carried out, argon is adopted to purge a ladle before pouring, no molten steel is exposed in the pouring process, the continuous casting superheat degree is controlled to be 15 ℃, the electromagnetic stirring parameter at the solidification end is 8HZ/400A, the convection movement of molten steel is enhanced, the superheat degree is eliminated, and the solidification structure of a casting blank and the segregation of control elements are improved.
Soaking treatment: the soaking temperature in the steel is 1260 ℃ and the soaking time is 60min.
Rolling: rough rolling is carried out for 5 times, rough rolling temperature is 1010 ℃, finish rolling is carried out for 7 times, the thickness of a plate blank is 200mm, the thickness of an intermediate blank is 45mm, and the thickness of a finished product is 5.0mm. Finish rolling inlet temperature 1060 ℃ and finish rolling temperature 875 ℃. Air cooling at a cooling rate of 12 ℃/s.
The finish rolling process is shown in Table 2:
TABLE 2 example 1 finish rolling process parameters
Crimping: the hot rolled plate is curled at 610 deg.c to further refine the structure and promote precipitation of fine second phases in the steel.
Example 2
The embodiment provides a single titanium microalloyed corrosion-resistant high-strength steel with high hole expansion rate, which comprises the following main components in percentage by weight: c:0.06%, mn:1.2%, ti:0.09%, alt:0.027%, cr:0.017%, cu:0.018%, ni:0.027%, N:0.001%, S:0.003%, P:0.002%, and the balance of Fe and unavoidable impurity elements.
The preparation process of the single titanium microalloyed corrosion-resistant high-strength steel with high hole expansion rate comprises the following steps: the high-strength steel is prepared by adopting converter smelting, LF refining, RH refining, continuous casting, heating, rolling and crimping.
Smelting in a converter: pretreatment of molten iron, P:0.002%. And the residual element conditions of molten iron and molten steel are noted before and during production, so that the standard requirements are met. Aluminum block: 0.33kg/t molten steel, and adjusted as appropriate according to tapping C and refining incoming components. Controlling tapping components: s:0.003%, P:0.002%. And slag blocking and tapping are carried out, so that the slag blocking effect is ensured.
LF: the target components and the actual conditions in the smelting process are adjusted to ensure that the chemical components of the steel meet the requirements: c:0.06%, mn:1.2%, alt:0.027%, cr:0.017%, cu:0.018%, ni:0.027%. When the alloy is added, the charging temperature should be controlled so as to avoid the adverse effect of severe temperature change on the temperature balance in the furnace and the smelting process.
RH refining: vacuum (less than or equal to 100 Pa) time: 15min; and after the molten pool is stable, adding the titanium-containing cored wire. Soft blowing time after adding titanium-containing cored wire: 15min.
Continuous casting: the whole process of protection pouring is carried out, argon is adopted to purge a ladle before pouring, no molten steel is exposed in the pouring process, the continuous casting superheat degree is controlled to be 15 ℃, the electromagnetic stirring parameter at the solidification end is 8HZ/400A, the convection movement of molten steel is enhanced, the superheat degree is eliminated, and the solidification structure of a casting blank and the segregation of control elements are improved.
Soaking treatment: the soaking temperature in the steel is 1260 ℃ and the soaking time is 60min.
Rolling: rough rolling is carried out for 5 times, rough rolling temperature is 1010 ℃, finish rolling is carried out for 7 times, the thickness of a plate blank is 200mm, the thickness of an intermediate blank is 45mm, and the thickness of a finished product is 5.0mm. Finish rolling inlet temperature 1060 ℃ and finish rolling temperature 875 ℃. Air cooling at a cooling rate of 12 ℃/s.
The finish rolling process is as in Table 2.
Crimping: the hot rolled plate is curled at 610 deg.c to further refine the structure and promote precipitation of fine second phases in the steel.
Example 3
The embodiment provides a single titanium microalloyed corrosion-resistant high-strength steel with high hole expansion rate, which comprises the following main components in percentage by weight: c:0.06%, mn:1.2%, ti:0.095%, alt:0.027%, cr:0.017%, cu:0.018%, ni:0.027%, N:0.001%, S:0.003%, P:0.002%, and the balance of Fe and unavoidable impurity elements.
The preparation process of the single titanium microalloyed corrosion-resistant high-strength steel with high hole expansion rate comprises the following steps: the high-strength steel is prepared by adopting converter smelting, LF refining, RH refining, continuous casting, heating, rolling and crimping.
Smelting in a converter: pretreatment of molten iron, P:0.002%. And the residual element conditions of molten iron and molten steel are noted before and during production, so that the standard requirements are met. Aluminum block: 0.33kg/t molten steel, and adjusted as appropriate according to tapping C and refining incoming components. Controlling tapping components: s:0.003%, P:0.002%. And slag blocking and tapping are carried out, so that the slag blocking effect is ensured.
LF: the target components and the actual conditions in the smelting process are adjusted to ensure that the chemical components of the steel meet the requirements: c:0.06%, mn:1.2%, alt:0.027%, cr:0.017%, cu:0.018%, ni:0.027%. When the alloy is added, the charging temperature should be controlled so as to avoid the adverse effect of severe temperature change on the temperature balance in the furnace and the smelting process.
RH refining: vacuum (less than or equal to 100 Pa) time: 15min; and after the molten pool is stable, adding the titanium-containing cored wire. Soft blowing time after adding titanium-containing cored wire: 15min.
Continuous casting: the whole process of protection pouring is carried out, argon is adopted to purge a ladle before pouring, no molten steel is exposed in the pouring process, the continuous casting superheat degree is controlled to be 15 ℃, the electromagnetic stirring parameter at the solidification end is 8HZ/400A, the convection movement of molten steel is enhanced, the superheat degree is eliminated, and the solidification structure of a casting blank and the segregation of control elements are improved.
Soaking treatment: the soaking temperature in the steel is 1260 ℃ and the soaking time is 60min.
Rolling: rough rolling is carried out for 5 times, rough rolling temperature is 1010 ℃, finish rolling is carried out for 7 times, the thickness of a plate blank is 200mm, the thickness of an intermediate blank is 45mm, and the thickness of a finished product is 5.0mm. Finish rolling inlet temperature 1060 ℃ and finish rolling temperature 875 ℃. Air cooling at a cooling rate of 12 ℃/s.
The finish rolling process is as in Table 2.
Crimping: the hot rolled plate is curled at 610 deg.c to further refine the structure and promote precipitation of fine second phases in the steel.
Comparative example 1
The comparative example provides a high-strength steel, which comprises the following main components in percentage by weight: c:0.06%, mn:1.2%, ti:0.07%, alt:0.027%, cr:0.017%, cu:0.018%, ni:0.027%, N:0.001%, S:0.003%, P:0.002%, and the balance of Fe and unavoidable impurity elements.
The preparation method comprises the following steps:
smelting in a converter: pretreatment of molten iron, P:0.002%. And the residual element conditions of molten iron and molten steel are noted before and during production, so that the standard requirements are met. Aluminum block: 0.33kg/t molten steel, and adjusted as appropriate according to tapping C and refining incoming components. Controlling tapping components: s:0.003%, P:0.002%. And slag blocking and tapping are carried out, so that the slag blocking effect is ensured.
LF: the target components and the actual conditions in the smelting process are adjusted to ensure that the chemical components of the steel meet the requirements: c:0.06%, mn:1.2%, alt:0.027%, cr:0.017%, cu:0.018%, ni:0.027%. When the alloy is added, the charging temperature should be controlled so as to avoid the adverse effect of severe temperature change on the temperature balance in the furnace and the smelting process.
RH refining: vacuum (less than or equal to 100 Pa) time: 15min; and after the molten pool is stable, adding the titanium-containing cored wire. Soft blowing time after adding titanium-containing cored wire: 15min.
Continuous casting: the whole process of protection pouring is carried out, argon is adopted to purge a ladle before pouring, no molten steel is exposed in the pouring process, the continuous casting superheat degree is controlled to be 15 ℃, the electromagnetic stirring parameter at the solidification end is 8HZ/400A, the convection movement of molten steel is enhanced, the superheat degree is eliminated, and the solidification structure of a casting blank and the segregation of control elements are improved.
Soaking treatment: the soaking temperature in the steel is 1260 ℃ and the soaking time is 60min.
Rolling: rough rolling is carried out for 5 times, rough rolling temperature is 1010 ℃, finish rolling is carried out for 7 times, the thickness of a plate blank is 200mm, the thickness of an intermediate blank is 45mm, and the thickness of a finished product is 5.0mm. Finish rolling inlet temperature 1060 ℃ and finish rolling temperature 875 ℃. Air cooling at a cooling rate of 12 ℃/s.
The finish rolling process is as in Table 2.
Crimping: the hot rolled plate is curled at 610 deg.c to further refine the structure and promote precipitation of fine second phases in the steel.
Comparative example 2
The comparative example provides a high-strength steel, which comprises the following main components in percentage by weight: c:0.06%, mn:1.2%, ti:0.15%, alt:0.027%, cr:0.017%, cu:0.018%, ni:0.027%, N:0.001%, S:0.003%, P:0.002%, and the balance of Fe and unavoidable impurity elements.
The preparation method comprises the following steps:
smelting in a converter: pretreatment of molten iron, P:0.002%. And the residual element conditions of molten iron and molten steel are noted before and during production, so that the standard requirements are met. Aluminum block: 0.33kg/t molten steel, and adjusted as appropriate according to tapping C and refining incoming components. Controlling tapping components: s:0.003%, P:0.002%. And slag blocking and tapping are carried out, so that the slag blocking effect is ensured.
LF: the target components and the actual conditions in the smelting process are adjusted to ensure that the chemical components of the steel meet the requirements: c:0.06%, mn:1.2%, alt:0.027%, cr:0.017%, cu:0.018%, ni:0.027%. When the alloy is added, the charging temperature should be controlled so as to avoid the adverse effect of severe temperature change on the temperature balance in the furnace and the smelting process.
RH refining: vacuum (less than or equal to 100 Pa) time: 15min; and after the molten pool is stable, adding the titanium-containing cored wire. Soft blowing time after adding titanium-containing cored wire: 15min.
Continuous casting: the whole process of protection pouring is carried out, argon is adopted to purge a ladle before pouring, no molten steel is exposed in the pouring process, the continuous casting superheat degree is controlled to be 15 ℃, the electromagnetic stirring parameter at the solidification end is 8HZ/400A, the convection movement of molten steel is enhanced, the superheat degree is eliminated, and the solidification structure of a casting blank and the segregation of control elements are improved.
Soaking treatment: the soaking temperature in the steel is 1260 ℃ and the soaking time is 60min.
Rolling: rough rolling is carried out for 5 times, rough rolling temperature is 1010 ℃, finish rolling is carried out for 7 times, the thickness of a plate blank is 200mm, the thickness of an intermediate blank is 45mm, and the thickness of a finished product is 5.0mm. Finish rolling inlet temperature 1060 ℃ and finish rolling temperature 875 ℃. Air cooling at a cooling rate of 12 ℃/s.
The finish rolling process is as in Table 2.
Crimping: the hot rolled plate is curled at 610 deg.c to further refine the structure and promote precipitation of fine second phases in the steel.
Comparative example 3
The comparative example provides a high-strength steel, which comprises the following main components in percentage by weight: c:0.06%, mn:1.2%, ti:0.09%, alt:0.027%, cr:0.017%, cu:0.018%, ni:0.018%, N:0.001%, S:0.003%, P:0.002%, and the balance of Fe and unavoidable impurity elements.
The preparation method comprises the following steps:
smelting in a converter: pretreatment of molten iron, P:0.002%. And the residual element conditions of molten iron and molten steel are noted before and during production, so that the standard requirements are met. Aluminum block: 0.33kg/t molten steel, and adjusted as appropriate according to tapping C and refining incoming components. Controlling tapping components: s:0.003%, P:0.002%. And slag blocking and tapping are carried out, so that the slag blocking effect is ensured.
LF: the target components and the actual conditions in the smelting process are adjusted to ensure that the chemical components of the steel meet the requirements: c:0.06%, mn:1.2%, alt:0.027%, cr:0.017%, cu:0.018%, ni:0.018%. When the alloy is added, the charging temperature should be controlled so as to avoid the adverse effect of severe temperature change on the temperature balance in the furnace and the smelting process.
RH refining: vacuum (less than or equal to 100 Pa) time: 15min; and after the molten pool is stable, adding the titanium-containing cored wire. Soft blowing time after adding titanium-containing cored wire: 15min.
Continuous casting: the whole process of protection pouring is carried out, argon is adopted to purge a ladle before pouring, no molten steel is exposed in the pouring process, the continuous casting superheat degree is controlled to be 15 ℃, the electromagnetic stirring parameter at the solidification end is 8HZ/400A, the convection movement of molten steel is enhanced, the superheat degree is eliminated, and the solidification structure of a casting blank and the segregation of control elements are improved.
Soaking treatment: the soaking temperature in the steel is 1260 ℃ and the soaking time is 60min.
Rolling: rough rolling is carried out for 5 times, rough rolling temperature is 1010 ℃, finish rolling is carried out for 7 times, the thickness of a plate blank is 200mm, the thickness of an intermediate blank is 45mm, and the thickness of a finished product is 5.0mm. Finish rolling inlet temperature 1060 ℃ and finish rolling temperature 875 ℃. Air cooling at a cooling rate of 12 ℃/s.
The finish rolling process is as in Table 2.
Crimping: the hot rolled plate is curled at 610 deg.c to further refine the structure and promote precipitation of fine second phases in the steel.
Comparative example 4
The comparative example provides a high-strength steel, which comprises the following main components in percentage by weight: c:0.06%, mn:1.2%, ti:0.09%, alt:0.027%, cr:0.017%, cu:0.010%, ni:0.027%, N:0.001%, S:0.003%, P:0.002%, and the balance of Fe and unavoidable impurity elements.
The preparation method comprises the following steps:
smelting in a converter: pretreatment of molten iron, P:0.002%. And the residual element conditions of molten iron and molten steel are noted before and during production, so that the standard requirements are met. Aluminum block: 0.33kg/t to 0.37kg/t molten steel, and the steel tapping C and the refining entering components are adjusted as appropriate. Controlling tapping components: s:0.003%, P:0.002%. And slag blocking and tapping are carried out, so that the slag blocking effect is ensured.
LF: the target components and the actual conditions in the smelting process are adjusted to ensure that the chemical components of the steel meet the requirements: c:0.06%, mn:1.2%, alt:0.027%, cr:0.017%, cu:0.010%, ni:0.027%. When the alloy is added, the charging temperature should be controlled so as to avoid the adverse effect of severe temperature change on the temperature balance in the furnace and the smelting process.
RH refining: vacuum (less than or equal to 100 Pa) time: 15min; and after the molten pool is stable, adding the titanium-containing cored wire. Soft blowing time after adding titanium-containing cored wire: 15min.
Continuous casting: the whole process of protection pouring is carried out, argon is adopted to purge a ladle before pouring, no molten steel is exposed in the pouring process, the continuous casting superheat degree is controlled to be 15 ℃, the electromagnetic stirring parameter at the solidification end is 8HZ/400A, the convection movement of molten steel is enhanced, the superheat degree is eliminated, and the solidification structure of a casting blank and the segregation of control elements are improved.
Soaking treatment: the soaking temperature in the steel is 1260 ℃ and the soaking time is 60min.
Rolling: rough rolling is carried out for 5 times, rough rolling temperature is 1010 ℃, finish rolling is carried out for 7 times, the thickness of a plate blank is 200mm, the thickness of an intermediate blank is 45mm, and the thickness of a finished product is 5.0mm. Finish rolling inlet temperature 1060 ℃ and finish rolling temperature 875 ℃. Air cooling at a cooling rate of 12 ℃/s.
The finish rolling process is as in Table 2.
Crimping: the hot rolled plate is curled at 610 deg.c to further refine the structure and promote precipitation of fine second phases in the steel.
Comparative example 5
The comparative example provides a high-strength steel, which comprises the following main components in percentage by weight: c:0.06%, mn:1.2%, ti:0.09%, alt:0.027%, cr:0.017%, cu:0.028%, ni:0.027%, N:0.001%, S:0.003%, P:0.002%, and the balance of Fe and unavoidable impurity elements.
The preparation method comprises the following steps:
smelting in a converter: pretreatment of molten iron, P:0.002%. And the residual element conditions of molten iron and molten steel are noted before and during production, so that the standard requirements are met. Aluminum block: 0.33kg/t to 0.37kg/t molten steel, and the steel tapping C and the refining entering components are adjusted as appropriate. Controlling tapping components: s:0.003%, P:0.002%. And slag blocking and tapping are carried out, so that the slag blocking effect is ensured.
LF: the target components and the actual conditions in the smelting process are adjusted to ensure that the chemical components of the steel meet the requirements: c:0.06%, mn:1.2%, alt:0.027%, cr:0.017%, cu:0.028%, ni:0.027%. When the alloy is added, the charging temperature should be controlled so as to avoid the adverse effect of severe temperature change on the temperature balance in the furnace and the smelting process.
RH refining: vacuum (less than or equal to 100 Pa) time: 15min; and after the molten pool is stable, adding the titanium-containing cored wire. Soft blowing time after adding titanium-containing cored wire: 15min.
Continuous casting: the whole process of protection pouring is carried out, argon is adopted to purge a ladle before pouring, no molten steel is exposed in the pouring process, the continuous casting superheat degree is controlled to be 15 ℃, the electromagnetic stirring parameter at the solidification end is 8HZ/400A, the convection movement of molten steel is enhanced, the superheat degree is eliminated, and the solidification structure of a casting blank and the segregation of control elements are improved.
Soaking treatment: the soaking temperature in the steel is 1260 ℃ and the soaking time is 60min.
Rolling: rough rolling is carried out for 5 times, rough rolling temperature is 1010 ℃, finish rolling is carried out for 7 times, the thickness of a plate blank is 200mm, the thickness of an intermediate blank is 45mm, and the thickness of a finished product is 5.0mm. Finish rolling inlet temperature 1060 ℃ and finish rolling temperature 875 ℃. Air cooling at a cooling rate of 12 ℃/s.
The finish rolling process is as in Table 2.
Crimping: the hot rolled plate is curled at 610 deg.c to further refine the structure and promote precipitation of fine second phases in the steel.
Comparative example 6
The comparative example provides a high-strength steel, which comprises the following main components in percentage by weight: c:0.06%, mn:1.2%, ti:0.10%, alt:0.027%, cr:0.010%, cu:0.018%, ni:0.027%, N:0.001%, S:0.003%, P:0.002%, and the balance of Fe and unavoidable impurity elements.
The preparation method comprises the following steps:
smelting in a converter: pretreatment of molten iron, P:0.002%. And the residual element conditions of molten iron and molten steel are noted before and during production, so that the standard requirements are met. Aluminum block: 0.33kg/t molten steel, and adjusted as appropriate according to tapping C and refining incoming components. Controlling tapping components: s:0.003%, P:0.002%. And slag blocking and tapping are carried out, so that the slag blocking effect is ensured.
LF: the target components and the actual conditions in the smelting process are adjusted to ensure that the chemical components of the steel meet the requirements: c:0.06%, mn:1.2%, alt:0.027%, cr:0.010%, cu:0.018%, ni:0.027%. When the alloy is added, the charging temperature should be controlled so as to avoid the adverse effect of severe temperature change on the temperature balance in the furnace and the smelting process.
RH refining: vacuum (less than or equal to 100 Pa) time: 15min; and after the molten pool is stable, adding the titanium-containing cored wire. Soft blowing time after adding titanium-containing cored wire: 15min.
Continuous casting: the whole process of protection pouring is carried out, argon is adopted to purge a ladle before pouring, no molten steel is exposed in the pouring process, the continuous casting superheat degree is controlled to be 15 ℃, the electromagnetic stirring parameter at the solidification end is 8HZ/400A, the convection movement of molten steel is enhanced, the superheat degree is eliminated, and the solidification structure of a casting blank and the segregation of control elements are improved.
Soaking treatment: the soaking temperature in the steel is 1260 ℃ and the soaking time is 60min.
Rolling: rough rolling is carried out for 5 times, rough rolling temperature is 1010 ℃, finish rolling is carried out for 7 times, the thickness of a plate blank is 200mm, the thickness of an intermediate blank is 45mm, and the thickness of a finished product is 5.0mm. Finish rolling inlet temperature 1060 ℃ and finish rolling temperature 875 ℃. Air cooling at a cooling rate of 12 ℃/s.
The finish rolling process is as in Table 2.
Crimping: the hot rolled plate is curled at 610 deg.c to further refine the structure and promote precipitation of fine second phases in the steel.
Comparative example 7
The comparative example provides a high-strength steel, which comprises the following main components in percentage by weight: c:0.06%, mn:1.2%, ti:0.10%, alt:0.027%, cr:0.025%, cu:0.018%, ni:0.027%, N:0.001%, S:0.003%, P:0.002%, and the balance of Fe and unavoidable impurity elements.
The preparation method comprises the following steps:
smelting in a converter: pretreatment of molten iron, P:0.002%. And the residual element conditions of molten iron and molten steel are noted before and during production, so that the standard requirements are met. Aluminum block: 0.33kg/t molten steel, and adjusted as appropriate according to tapping C and refining incoming components. Controlling tapping components: s:0.003%, P:0.002%. And slag blocking and tapping are carried out, so that the slag blocking effect is ensured.
LF: the target components and the actual conditions in the smelting process are adjusted to ensure that the chemical components of the steel meet the requirements: c:0.06%, mn:1.2%, alt:0.027%, cr:0.025%, cu:0.018%, ni:0.027%. When the alloy is added, the charging temperature should be controlled so as to avoid the adverse effect of severe temperature change on the temperature balance in the furnace and the smelting process.
RH refining: vacuum (less than or equal to 100 Pa) time: 15min; and after the molten pool is stable, adding the titanium-containing cored wire. Soft blowing time after adding titanium-containing cored wire: 15min.
Continuous casting: the whole process of protection pouring is carried out, argon is adopted to purge a ladle before pouring, no molten steel is exposed in the pouring process, the continuous casting superheat degree is controlled to be 15 ℃, the electromagnetic stirring parameter at the solidification end is 8HZ/400A, the convection movement of molten steel is enhanced, the superheat degree is eliminated, and the solidification structure of a casting blank and the segregation of control elements are improved.
Soaking treatment: the soaking temperature in the steel is 1260 ℃ and the soaking time is 60min.
Rolling: rough rolling is carried out for 5 times, rough rolling temperature is 1010 ℃, finish rolling is carried out for 7 times, the thickness of a plate blank is 200mm, the thickness of an intermediate blank is 45mm, and the thickness of a finished product is 5.0mm. Finish rolling inlet temperature 1060 ℃ and finish rolling temperature 875 ℃. Air cooling at a cooling rate of 12 ℃/s.
The finish rolling process is as in Table 2.
Crimping: the hot rolled plate is curled at 610 deg.c to further refine the structure and promote precipitation of fine second phases in the steel.
Comparative example 8
The comparative example provides a high-strength steel, which comprises the following main components in percentage by weight: c:0.06%, mn:1.2%, ti:0.10%, alt:0.027%, cr:0.017%, cu:0.018%, ni:0.027%, N:0.001%, S:0.003%, P:0.002%, and the balance of Fe and unavoidable impurity elements.
The preparation method comprises the following steps:
smelting in a converter: pretreatment of molten iron, P:0.002%. And the residual element conditions of molten iron and molten steel are noted before and during production, so that the standard requirements are met. Aluminum block: 0.33kg/t molten steel, and adjusted as appropriate according to tapping C and refining incoming components. Controlling tapping components: s:0.003%, P:0.002%. And slag blocking and tapping are carried out, so that the slag blocking effect is ensured.
LF: the target components and the actual conditions in the smelting process are adjusted to ensure that the chemical components of the steel meet the requirements: c:0.06%, mn:1.2%, alt:0.027%, cr:0.017%, cu:0.018%, ni:0.027%. When the alloy is added, the charging temperature should be controlled so as to avoid the adverse effect of severe temperature change on the temperature balance in the furnace and the smelting process. After the molten pool is stable, adding the titanium-containing cored wire
Continuous casting: the whole process of protection pouring is carried out, argon is adopted to purge a ladle before pouring, no molten steel is exposed in the pouring process, the continuous casting superheat degree is controlled to be 15 ℃, the electromagnetic stirring parameter at the solidification end is 8HZ/400A, the convection movement of molten steel is enhanced, the superheat degree is eliminated, and the solidification structure of a casting blank and the segregation of control elements are improved.
Soaking treatment: the soaking temperature in the steel is 1260 ℃ and the soaking time is 60min.
Rolling: rough rolling is carried out for 5 times, rough rolling temperature is 1010 ℃, finish rolling is carried out for 7 times, the thickness of a plate blank is 200mm, the thickness of an intermediate blank is 45mm, and the thickness of a finished product is 5.0mm. Finish rolling inlet temperature 1060 ℃ and finish rolling temperature 875 ℃. Air cooling at a cooling rate of 12 ℃/s.
The finish rolling process is as in Table 2.
Crimping: the hot rolled plate is curled at 610 deg.c to further refine the structure and promote precipitation of fine second phases in the steel.
Comparative example 9
The comparative example provides a high-strength steel, which comprises the following main components in percentage by weight: c:0.06%, mn:1.2%, ti:0.10%, alt:0.027%, cr:0.017%, cu:0.018%, ni:0.027%, N:0.001%, S:0.003%, P:0.002%, and the balance of Fe and unavoidable impurity elements.
The preparation method comprises the following steps:
smelting in a converter: pretreatment of molten iron, P:0.002%. And the residual element conditions of molten iron and molten steel are noted before and during production, so that the standard requirements are met. Aluminum block: 0.33kg/t molten steel, and adjusted as appropriate according to tapping C and refining incoming components. Controlling tapping components: s:0.003%, P:0.002%. And slag blocking and tapping are carried out, so that the slag blocking effect is ensured.
LF: the target components and the actual conditions in the smelting process are adjusted to ensure that the chemical components of the steel meet the requirements: c:0.06%, mn:1.2%, alt:0.027%, cr:0.017%, cu:0.018%, ni:0.027%. When the alloy is added, the charging temperature should be controlled so as to avoid the adverse effect of severe temperature change on the temperature balance in the furnace and the smelting process.
RH refining: vacuum (less than or equal to 100 Pa) time: 15min; and after the molten pool is stable, adding the titanium-containing cored wire. Soft blowing time after adding titanium-containing cored wire: 15min.
Continuous casting: the whole process of protection pouring is carried out, argon is adopted to purge a ladle before pouring, no molten steel is exposed in the pouring process, the continuous casting superheat degree is controlled to be 15 ℃, the electromagnetic stirring parameter at the solidification end is 8HZ/400A, the convection movement of molten steel is enhanced, the superheat degree is eliminated, and the solidification structure of a casting blank and the segregation of control elements are improved.
Soaking treatment: the soaking temperature in the steel is 1260 ℃ and the soaking time is 60min.
Rolling: rough rolling is carried out for 5 times, rough rolling temperature is 1010 ℃, finish rolling is carried out for 7 times, the thickness of a plate blank is 200mm, the thickness of an intermediate blank is 45mm, and the thickness of a finished product is 5.0mm. Finish rolling inlet temperature 1060 ℃ and finish rolling temperature 875 ℃. Air cooling at a cooling rate of 12 ℃/s.
The finish rolling process is as in Table 2.
Crimping: the hot rolled plate is curled at 580 deg.c to further refine the structure and promote the precipitation of fine second phase in the steel.
Comparative example 10
The comparative example provides a high-strength steel, which comprises the following main components in percentage by weight: c:0.06%, mn:1.2%, ti:0.10%, alt:0.027%, cr:0.017%, cu:0.018%, ni:0.027%, N:0.001%, S:0.003%, P:0.002%, and the balance of Fe and unavoidable impurity elements.
The preparation method comprises the following steps:
smelting in a converter: pretreatment of molten iron, P:0.002%. And the residual element conditions of molten iron and molten steel are noted before and during production, so that the standard requirements are met. Aluminum block: 0.33kg/t molten steel, and adjusted as appropriate according to tapping C and refining incoming components. Controlling tapping components: s:0.003%, P:0.002%. And slag blocking and tapping are carried out, so that the slag blocking effect is ensured.
LF: the target components and the actual conditions in the smelting process are adjusted to ensure that the chemical components of the steel meet the requirements: c:0.06%, mn:1.2%, alt:0.027%, cr:0.017%, cu:0.018%, ni:0.027%. When the alloy is added, the charging temperature should be controlled so as to avoid the adverse effect of severe temperature change on the temperature balance in the furnace and the smelting process.
RH refining: vacuum (less than or equal to 100 Pa) time: 15min; and after the molten pool is stable, adding the titanium-containing cored wire. Soft blowing time after adding titanium-containing cored wire: 15min.
Continuous casting: the whole process of protection pouring is carried out, argon is adopted to purge a ladle before pouring, no molten steel is exposed in the pouring process, the continuous casting superheat degree is controlled to be 15 ℃, the electromagnetic stirring parameter at the solidification end is 8HZ/400A, the convection movement of molten steel is enhanced, the superheat degree is eliminated, and the solidification structure of a casting blank and the segregation of control elements are improved.
Soaking treatment: the soaking temperature in the steel is 1260 ℃ and the soaking time is 60min.
Rolling: rough rolling is carried out for 5 times, rough rolling temperature is 1010 ℃, finish rolling is carried out for 7 times, the thickness of a plate blank is 200mm, the thickness of an intermediate blank is 45mm, and the thickness of a finished product is 5.0mm. Finish rolling inlet temperature 1060 ℃ and finish rolling temperature 875 ℃. Air cooling at a cooling rate of 12 ℃/s.
The finish rolling process is as in Table 2.
Crimping: the hot rolled plate is curled at 630 ℃, further refining the structure and promoting precipitation of fine second phases in the steel.
Comparative experimental analysis:
taking example 1 as an example (fig. 1, photographs of structures, crystal grains, precipitated phases, intragranular and grain boundary dislocation morphology in the high-strength steel obtained in example 1), after a proper amount of Ti, ni, cu, cr is added into the steel, small-size TiC precipitated phases are generated in the steel due to the strengthening effect of Ti, the grain boundaries are pinned, steel crystal grains are refined, and meanwhile, dislocation movement is blocked by second-phase particles, so that the toughness of the steel is obviously improved under the effects of dislocation strengthening and fine-grain strengthening. The synergistic effect of Ti and Ni can slow down the growth rate of grains, thereby refining the grains. The synergistic effect of Cu and Cr can generate copper-chromium-rich precipitate phase in steel, limit grain boundary migration and grain growth, and thus realize the effect of grain refinement. The grain boundary area can be increased by the small grain size, the grain orientations at two sides of the grain boundary are different, cracks penetrate through the inside of the grains or extend along the grain boundaries, when phase boundaries in the grains are encountered, the crack extension is blocked due to the existence of the phase differences, the larger the energy consumed by the crack in extension is, the slower the crack extension is, and the micro crack penetration extension is effectively blocked, so that the hole expansion rate of the steel is higher. Due to the synergistic effect of Ni, cu and Cr, a relatively stable passivation film is formed on the surface of the steel, the corrosion potential of the steel is relatively high, and the corrosion resistance of the steel is relatively good.
Compared with examples 1, 2 and 3, the addition of a small amount of Ti in comparative example 1 significantly reduces the strength of the steel, and the elongation and low-temperature impact toughness are reduced, and since the Ti content is low, a sufficient strengthening phase is not generated in the steel, the grain size of the steel is large (FIG. 2, a photograph of the grain morphology in the high-strength steel obtained in comparative example 1), resulting in a reduction in the performance of the steel.
In comparative example 2, excessive Ti was added, but the elongation and low-temperature impact toughness of the steel were remarkably reduced although the strength of the steel was not remarkably reduced, and as the Ti content in the steel was increased, a large number of large-sized inclusions were generated in the steel (fig. 3, photographs of the inclusion morphology in the high-strength steel obtained in comparative example 2) and the toughness and plasticity of the steel were reduced. Large-sized inclusions tend to become crack initiation points, causing crack propagation and fracture to occur, thereby reducing toughness and fracture resistance of the steel.
Compared with example 1, the Ni content added in comparative example 3 was too low, the grain size of the steel increased, the hole expansion ratio decreased, the corrosion potential of the steel significantly decreased, and the corrosion resistance of the steel was poor.
Compared with example 1, comparative example 4 added a small amount of Cu, the grain size of the steel increased, the hole expansion ratio decreased, the corrosion potential of the steel significantly decreased, and the corrosion resistance of the steel was poor.
In comparative example 5, in which Cu was excessively added, the tensile impact properties of the steel material were lowered as compared with example 1.
Compared with example 1, in comparative example 6, a small amount of Cr was added, the passivation film on the surface of the steel material was unstable, the corrosion potential of the steel material was remarkably lowered, and the corrosion resistance of the steel material was poor.
Compared with example 1, the addition of excessive Cr in comparative example 7 increases the strength of the steel by the dispersed precipitation of granular bainite and a large amount of fine carbides, but the precipitation positions of the granular bainite and the fine carbides are located at grain boundaries, the hole expansion ratio is destroyed by the decrease of the grain boundary strength and the strength difference between the grain boundary strength and the ferrite matrix, and the hole expansion ratio of the sample is reduced to a certain extent (FIG. 4, a picture of the structure morphology in the high-strength steel obtained in comparative example 7).
In comparative example 8, RH refining was omitted and the grain size of the steel material was increased as compared with example 1. The proper refining temperature can promote grain refinement and improve the toughness and impact toughness of the steel. RH refining can also remove impurities in molten steel, and improve purity and corrosion resistance. Since RH refining was omitted in comparative example eight, the toughness and corrosion resistance of the steel material were lowered.
The curl temperature of the steel material in comparative example 9 is too low compared with example 1, and the low coiling temperature may cause increased carbide precipitation in the steel sheet while generating a large residual stress on the surface of the steel sheet, thereby reducing the toughness of the steel material.
The steel material of comparative example 10 has a curl temperature excessively high compared with example 1, and an excessively high coiling temperature accelerates the grain growth rate of the steel sheet, resulting in an increase in grain size. This reduces the structural uniformity of the steel sheet and also reduces the strength and toughness of the steel.
The relevant performance parameters of the steels obtained in the examples and comparative examples are shown in the following Table 3:
TABLE 3 Performance parameters
The strength of the product is improved through the single Ti element, the conventional component design for improving the strength through the composite addition of the Nb element and the Ti element is replaced, and the alloy addition cost of the product is reduced. Ni, cu and Cr in the steel are controlled in a narrower range, the grain size and the structure uniformity are controlled through the synergistic effect of Ti, ni, cu, cr, and the toughness and the reaming performance of the steel are improved; by utilizing the cooperative regulation and control of Ni, cu and Cr, a relatively stable passivation film is formed on the surface of the steel, so that the corrosion potential of the steel is improved, and the steel has excellent corrosion resistance. The RH refining furnace is adopted to remove impurities in steel, so that the purity of the steel is improved, the hot rolled plate is directly curled at 600-610 ℃, grains can be effectively refined, the performance of the steel is improved, processing steps and equipment can be reduced, and the production cost is reduced.
Specific:
1. the Ti microalloying mode is adopted to produce the high-strength steel, so that the strength and toughness of the steel are improved, meanwhile, the steel has higher hole expansion rate, the conventional component design for improving the strength by compositely adding Nb element and Ti element is replaced, and the alloy adding cost of the product is reduced.
2. The method of Ti, ni, cu, cr cooperative regulation and control is adopted to produce the high-strength corrosion-resistant steel, so that the steel has higher hole expansion rate and simultaneously ensures the corrosion resistance of the high-strength steel.
3. The RH refining furnace is adopted to remove impurities in steel, so that the purity of the steel is improved, and the hot rolled plate is directly curled at 600-610 ℃, so that not only can grains be effectively refined to improve the performance of the steel, but also the processing steps and equipment can be reduced, and the production cost is reduced.
4. It is proposed that relatively narrow process parameters can more effectively cope with fluctuations in steel properties due to Ti-labile chemistry.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.
Furthermore, those skilled in the art will appreciate that while some embodiments herein include some features but not others included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the present application and form different embodiments. For example, in the claims below, any of the claimed embodiments may be used in any combination. The information disclosed in this background section is only for enhancement of understanding of the general background of the application and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.
Claims (9)
1. The single-titanium microalloyed corrosion-resistant high-strength steel with high hole expansion rate is characterized by comprising the following components in percentage by mass:
c:0.06% -0.07%, mn:1.1% -1.5%, ti:0.09% -0.10%, alt:0.026% -0.03%, cr:0.015% -0.020%, cu:0.016% -0.022%, ni:0.024-0.027%, N:0.001% -0.003%, S:0-0.005%, P:0-0.003%, and the balance of Fe and unavoidable impurity elements;
the preparation method comprises the following steps:
sequentially carrying out converter smelting, LF refining, RH refining, continuous casting, soaking treatment, rolling and crimping on the raw materials to obtain the high-expansion-ratio single-titanium microalloyed corrosion-resistant high-strength steel;
The superheat degree of continuous casting is controlled to be 15-20 ℃, and the soaking temperature is 1240-1260 ℃; the rolling comprises rough rolling and finish rolling, wherein the temperature of the rough rolling is 1010-1060 ℃, the inlet temperature of the finish rolling is 1060-1070 ℃, the finishing temperature is 875-885 ℃, and the air cooling speed is 11.9-13.5 ℃/s; the temperature of the crimping is 600-610 ℃.
2. The high-expansion-ratio single-titanium microalloyed corrosion-resistant high-strength steel according to claim 1, wherein the molten iron smelted by the converter is pretreated, and the content of P is controlled to be not higher than 0.002%.
3. The high-expansion-ratio single-titanium microalloyed corrosion-resistant high-strength steel according to claim 1, wherein 0.33-0.37kg/t molten steel of aluminum block is added in the converter smelting process.
4. The high-expansion-ratio single-titanium microalloyed corrosion-resistant high-strength steel according to claim 1, wherein the converter smelting control tapping component has an S content of not more than 0.005% and a P content of not more than 0.003%.
5. The high-expansion-ratio single-titanium microalloyed corrosion-resistant high-strength steel according to claim 1, wherein the degree of vacuum of the RH refining is not higher than 100Pa, and the time of the RH refining is 15-20min.
6. The high-expansion-ratio single-titanium microalloyed corrosion-resistant high-strength steel according to claim 1, wherein a titanium-containing cored wire is added in the RH refining process, and soft blowing is performed after the titanium-containing cored wire is added, wherein the soft blowing time is 10-20min.
7. The high-expansion-ratio single-titanium microalloyed corrosion-resistant high-strength steel according to claim 1, wherein the solidification end of the continuous casting adopts electromagnetic stirring, and the parameter is (7-10) HZ/400A.
8. The high expansion ratio single titanium microalloyed corrosion resistant high strength steel of claim 1, wherein said soaking time is 60-70min.
9. The high expansion ratio single titanium microalloyed corrosion resistant high strength steel of any one of claims 1 to 8, wherein said rough rolling is performed in 4 to 5 passes and said finish rolling is performed in 5 to 7 passes.
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| JP2010090476A (en) * | 2008-09-11 | 2010-04-22 | Nippon Steel Corp | High strength hot rolled steel sheet having excellent hole expansibility and method for producing the same |
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| CN113481430A (en) * | 2021-06-10 | 2021-10-08 | 马鞍山钢铁股份有限公司 | 800 MPa-grade boron-containing hot-dip galvanized dual-phase steel with enhanced hole expansion performance and production method thereof |
| CN114107792A (en) * | 2020-08-31 | 2022-03-01 | 宝山钢铁股份有限公司 | 780 MPa-grade high-surface ultrahigh-hole-expansion steel and manufacturing method thereof |
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| EP3925771A1 (en) * | 2020-06-16 | 2021-12-22 | SSAB Technology AB | High strength steel product and method of manufacturing the same |
| CN114107798A (en) * | 2020-08-31 | 2022-03-01 | 宝山钢铁股份有限公司 | 980 MPa-grade bainite high-reaming steel and manufacturing method thereof |
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| JP2010090476A (en) * | 2008-09-11 | 2010-04-22 | Nippon Steel Corp | High strength hot rolled steel sheet having excellent hole expansibility and method for producing the same |
| CN109852893A (en) * | 2019-03-15 | 2019-06-07 | 本钢板材股份有限公司 | A kind of low-temperature high-toughness refractory steel and preparation method thereof |
| CN114107792A (en) * | 2020-08-31 | 2022-03-01 | 宝山钢铁股份有限公司 | 780 MPa-grade high-surface ultrahigh-hole-expansion steel and manufacturing method thereof |
| CN113481430A (en) * | 2021-06-10 | 2021-10-08 | 马鞍山钢铁股份有限公司 | 800 MPa-grade boron-containing hot-dip galvanized dual-phase steel with enhanced hole expansion performance and production method thereof |
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