US20060144482A1 - Method of producing a cold-rolled band of dual-phase steel with a ferritic/martensitic structure and band thus obtained - Google Patents
Method of producing a cold-rolled band of dual-phase steel with a ferritic/martensitic structure and band thus obtained Download PDFInfo
- Publication number
- US20060144482A1 US20060144482A1 US10/544,206 US54420604A US2006144482A1 US 20060144482 A1 US20060144482 A1 US 20060144482A1 US 54420604 A US54420604 A US 54420604A US 2006144482 A1 US2006144482 A1 US 2006144482A1
- Authority
- US
- United States
- Prior art keywords
- strip
- temperature
- cooling
- rolled
- steel strip
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 229910000734 martensite Inorganic materials 0.000 title claims abstract description 34
- 238000000034 method Methods 0.000 title claims abstract description 26
- 229910000885 Dual-phase steel Inorganic materials 0.000 title claims abstract description 7
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 31
- 239000010959 steel Substances 0.000 claims abstract description 31
- 238000001816 cooling Methods 0.000 claims abstract description 25
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 18
- 239000000203 mixture Substances 0.000 claims abstract description 18
- 238000000137 annealing Methods 0.000 claims abstract description 10
- 239000012535 impurity Substances 0.000 claims abstract description 9
- 229910052742 iron Inorganic materials 0.000 claims abstract description 9
- 239000000126 substance Substances 0.000 claims abstract description 8
- 238000005496 tempering Methods 0.000 claims abstract description 8
- 229910052757 nitrogen Inorganic materials 0.000 claims abstract description 6
- 238000005097 cold rolling Methods 0.000 claims abstract description 4
- 238000003723 Smelting Methods 0.000 claims description 8
- 238000010791 quenching Methods 0.000 claims description 7
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 6
- 230000000171 quenching effect Effects 0.000 claims description 5
- 238000004519 manufacturing process Methods 0.000 claims description 4
- 238000010583 slow cooling Methods 0.000 claims description 3
- 238000005098 hot rolling Methods 0.000 abstract description 2
- 238000002360 preparation method Methods 0.000 abstract 1
- 238000004804 winding Methods 0.000 abstract 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 5
- 229910052799 carbon Inorganic materials 0.000 description 5
- 239000011572 manganese Substances 0.000 description 5
- 239000011651 chromium Substances 0.000 description 4
- 238000001953 recrystallisation Methods 0.000 description 4
- 238000005096 rolling process Methods 0.000 description 4
- 238000011282 treatment Methods 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 238000012935 Averaging Methods 0.000 description 2
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- 229910001567 cementite Inorganic materials 0.000 description 2
- 230000018109 developmental process Effects 0.000 description 2
- 229910052748 manganese Inorganic materials 0.000 description 2
- 229910052710 silicon Inorganic materials 0.000 description 2
- 239000010703 silicon Substances 0.000 description 2
- 239000006104 solid solution Substances 0.000 description 2
- 229910000859 α-Fe Inorganic materials 0.000 description 2
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 1
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 1
- 230000032683 aging Effects 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- -1 aluminum nitrides Chemical class 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 230000002939 deleterious effect Effects 0.000 description 1
- 230000001627 detrimental effect Effects 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- KSOKAHYVTMZFBJ-UHFFFAOYSA-N iron;methane Chemical compound C.[Fe].[Fe].[Fe] KSOKAHYVTMZFBJ-UHFFFAOYSA-N 0.000 description 1
- 230000002045 lasting effect Effects 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 239000011574 phosphorus Substances 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 230000001376 precipitating effect Effects 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 238000009736 wetting Methods 0.000 description 1
- 239000011701 zinc Substances 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
- C21D8/0236—Cold rolling
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/18—Hardening; Quenching with or without subsequent tempering
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
- C21D8/0273—Final recrystallisation annealing
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/18—Hardening; Quenching with or without subsequent tempering
- C21D1/185—Hardening; Quenching with or without subsequent tempering from an intercritical temperature
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/005—Ferrite
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/008—Martensite
Definitions
- the present invention relates to a process for producing a cold-rolled ferritic/martensitic dual-phase steel strip and to a strip that can be obtained by this process, which is more particularly intended for the production of automobile parts by deep drawing.
- Ultrahigh-strength steels have been developed in recent years, especially so as to meet the specific requirements of the automobile industry, which are in particular the reduction in weight, and therefore in thickness, of the parts and the improvement in safety afforded by the increase in fatigue strength and impact behavior of the parts. These improvements must also not degrade the formability of the steel sheet used for producing the parts.
- steels with a single-phase structure which have a high mean anisotropy coefficient r but have only moderate mechanical properties, with a tensile strength R m not exceeding 400 MPa.
- the object of the present invention is to remedy the drawbacks of the steels of the prior art by proposing a steel strip capable of deep drawing and having at the same time excellent mechanical properties and excellent anisotropy characteristics.
- the first subject of the invention is a process for producing a cold-rolled ferritic/martensitic dual-phase steel strip, characterized in that a slab, the chemical composition of which comprises, by weight:
- the cooling rate between 600° C. and the ambient temperature being between 100° C./s and 1500° C./s;
- the annealing and cooling operations being carried out in such a way that the strip finally contains from 1 to 15% martensite.
- the chemical composition of the steel furthermore comprises, by weight:
- the strip is hot rolled at a temperature above 850° C.
- the strip is hot coiled at a temperature of between 550 and 750° C.
- the strip is cold rolled with a reduction ratio of between 70 and 80%;
- the continuous annealing of the cold-rolled strip comprises a temperature rise phase followed by a soak phase at a predetermined temperature
- the soak temperature is between Ac 1 and 900° C.
- the soak temperature is between 750 and 850° C.
- the cooling down to the ambient temperature comprises a first, slow cooling step between the soak temperature and 600° C., during which the cooling rate is less than 50° C./s, followed by a second cooling step at a higher rate, of between 100° C./s and 1500° C./s, down to the ambient temperature.
- the second subject of the invention is a cold-rolled ferritic/martensitic dual-phase steel strip, the chemical composition of which comprises, by weight:
- composition of the strip is the following:
- the steel according to the invention may also include the following features, by themselves or in combination:
- the third subject of the invention is a steel strip according to the invention for the production of automobile parts by deep drawing.
- the process according to the invention consists in hot rolling a slab of specific composition and then in coiling the hot-rolled strip obtained at a temperature of between 550 and 850° C.
- This high-temperature coiling operation is favorable to the development of what is called a texture, that is to say an anisotropic structure. This is because such a coiling operation makes it possible for the Fe 3 C cementite precipitates to coalesce and to reduce the amount of carbon going back into solution during the anneal, this being detrimental to the development of the recrystallization texture.
- Water quenching allows substantial proportions of carbide phases to be formed in the composition in question. It is possible to reduce the amount of martensitic phase formed by lowering the soak temperature toward lower values in the intercritical range, or else by carrying out a slow cooling operation before the quench.
- this tempering operation is in no case an averaging treatment, as is found in the prior art. This is because these averaging treatments, which are generally carried out between 300 and 500° C., have in particular the effect of suppressing the martensite, which is an essential element of the present invention.
- the tempering optionally carried out according to the invention consists in precipitating some of the carbon in solid solution trapped in the martensite, without reducing the proportion of this martensite.
- the maximum temperature of this tempering operation is 300° C., preferably 250° C. and more particularly preferably 200° C.
- composition according to the invention includes carbon with a content of between 0.010% and 0.100%. This element is essential for obtaining good mechanical properties but it must not be present in too great an amount, as it would cause an excessive proportion of martensitic phase to be formed.
- Manganese with a content of between 0.050% and 1.0%. Manganese improves the yield strength of the steel, but greatly reduces its ductility. This is why its content is limited.
- the composition also includes chromium with a content of between 0.010% and 1.0%, which helps in the desired martensite formation.
- the composition also includes silicon with a content of between 0.010% and 0.50%. This greatly improves the yield strength of the steel, but slightly reduces its ductility and degrades its coatability.
- the composition also includes phosphorus with a content of between 0.001% and 0.20%, which hardens the microstructure without affecting its texture.
- the composition also includes aluminum with a content of between 0.010% and 0.10%, which prevents aging by nitrogen trapping.
- the balance of the compositions consists of iron and inevitable impurities resulting from the smelting.
- the two grades were austenized at 1250° C. for one hour, so as to dissolve the aluminum nitrides.
- the slabs were then hot rolled in such a way that the end-of-rolling temperature was above 900° C., the value of AR 3 for both grades being about 870° C.
- the hot-rolled strips were then cooled by water quenching, at a cooling rate of around 25° C./s, until the coiling temperature was reached.
- Grade A was coiled at 720° C.
- one specimen of grade B was coiled at 550° C. and another at 720 ° C.
- the various specimens were then cold rolled so as to achieve a reduction ratio of 75%, then they underwent an annealing treatment at a soak temperature of 750° C. in the case of some specimens and 800° C. in the case of the others.
- the cooling down to the ambient temperature was then carried out at a rate of around 25° C./s by water quenching.
- FIG. 1 shows the relationship between the mean coefficient r and the content of martensite formed %m for grades A and B. It may be seen that the higher the martensite content, the more anisotropic the steel.
- FIG. 2 shows the microstructure obtained with grade A, coiled at 720° C. and then annealed at 750° C. in order finally to obtain 12% martensite.
- the ferrite and the martensite formed can be clearly distinguished in the figure.
Abstract
The invention relates to a method of producing a cold-rolled band of dual-phase steel with a ferritic/martensitic structure. The inventive method consists in hot rolling a slab having a chemical composition which comprises, by weight, 0.01%≦C≦0.1%., 0.05%≦Mn≦1%, 0.01%≦Cr≦1%, 0.01%≦Si≦0.5%, 0.001%≦P≦0.2%, 0.01%≦Al≦0.1%, N≦0.01%, the remainder being iron and impurities resulting from the preparation thereof. The method also comprises the following subsequent steps consisting in: hot winding the band obtained at a temperature of between 550 and 850° C.; cold rolling the band with a reduction ratio of between 60 and 90%; annealing the band continuously in the intercritical region; cooling said band to ambient temperature, in one or more steps, the rate of cooling between 600° C. and ambient temperature being between 100° C./s and 1500° C/s; and, optionally, tempering same at a temperature of less than 300° C. The aforementioned annealing and cooling operations are performed such that the end band comprises between 1 and 15% martensite. The invention also relates to the steel band thus formed.
Description
- The present invention relates to a process for producing a cold-rolled ferritic/martensitic dual-phase steel strip and to a strip that can be obtained by this process, which is more particularly intended for the production of automobile parts by deep drawing.
- Ultrahigh-strength steels have been developed in recent years, especially so as to meet the specific requirements of the automobile industry, which are in particular the reduction in weight, and therefore in thickness, of the parts and the improvement in safety afforded by the increase in fatigue strength and impact behavior of the parts. These improvements must also not degrade the formability of the steel sheet used for producing the parts.
- Thus, dual-phase steels have been developed in which the structure is ferritic/martensitic, which make it possible to achieve a tensile strength Rm of more than 400 MPa but which do not have good drawability characteristics, since their mean anisotropy coefficient r is close to 1. Moreover, their galvanizability is poor, since they contain large amounts of silicon or other elements deleterious to good wetting of the surface of the strip by the molten zinc.
- Also known are steels with a single-phase structure, which have a high mean anisotropy coefficient r but have only moderate mechanical properties, with a tensile strength Rm not exceeding 400 MPa.
- As examples, mention may be made of low-interstitial steels and aluminum-killed reparkerized steels. Attempts at enhancing the conventional hardening mechanisms for these types of steel fail to appreciably improve their mechanical properties. Furthermore, this steel must be capable of being galvanized.
- The object of the present invention is to remedy the drawbacks of the steels of the prior art by proposing a steel strip capable of deep drawing and having at the same time excellent mechanical properties and excellent anisotropy characteristics.
- For this purpose, the first subject of the invention is a process for producing a cold-rolled ferritic/martensitic dual-phase steel strip, characterized in that a slab, the chemical composition of which comprises, by weight:
-
- 0.010%≦C≦0.100%
- 0.050%≦Mn≦1.0%
- 0.010%≦Cr≦1.0%
- 0.010%≦Si≦0.50%
- 0.001%≦P≦0.20%
- 0.010%≦Al≦0.10%
- N≦0.010%
the balance being iron and impurities resulting from the smelting, is hot rolled, said process then comprising the steps consisting in:
- coiling the hot-rolled strip obtained at a temperature of between 550 and 850° C.; then
- cold rolling the strip with a reduction ratio of between 60 and 90%; then
- annealing the strip continuously in the intercritical range; and
- cooling it down to the ambient temperature in one or more steps, the cooling rate between 600° C. and the ambient temperature being between 100° C./s and 1500° C./s; and
- optionally tempering it at a temperature below 300° C.,
- the annealing and cooling operations being carried out in such a way that the strip finally contains from 1 to 15% martensite.
- In a preferred method of implementation, the chemical composition of the steel furthermore comprises, by weight:
-
- 0.020%≦C≦0.060%
- 0.300%≦Mn≦0.500%
- 0.010%≦Cr≦1.0%
- 0.010%≦Si≦0.50%
- 0.010%≦P≦0.100%
- 0.010%≦Al≦0.10%
- N≦0.010%
the balance being iron and impurities resulting from the smelting.
- The process according to the invention may also include the following features, by themselves or in combination:
- the strip is hot rolled at a temperature above 850° C.;
- the strip is hot coiled at a temperature of between 550 and 750° C.;
- the strip is cold rolled with a reduction ratio of between 70 and 80%;
- the continuous annealing of the cold-rolled strip comprises a temperature rise phase followed by a soak phase at a predetermined temperature;
- the soak temperature is between Ac1 and 900° C.;
- the soak temperature is between 750 and 850° C.;
- the cooling down to the ambient temperature comprises a first, slow cooling step between the soak temperature and 600° C., during which the cooling rate is less than 50° C./s, followed by a second cooling step at a higher rate, of between 100° C./s and 1500° C./s, down to the ambient temperature.
- The second subject of the invention is a cold-rolled ferritic/martensitic dual-phase steel strip, the chemical composition of which comprises, by weight:
- In a preferred embodiment, the composition of the strip is the following:
-
- 0.020%≦C≦0.060%
- 0.300%≦Mn≦0.500%
- 0.010%≦Cr≦1.0%
- 0.010%≦Si≦0.50%
- 0.010%≦P≦0.100%
- 0.010%≦Al≦0.10%
- N≦0.010%
the balance being iron and impurities resulting from the smelting.
- The steel according to the invention may also include the following features, by themselves or in combination:
- it has a tensile strength Rm of greater than 450 MPa;
- it has a tensile strength Rm of greater than 500 MPa;
- it has a tensile strength Rm of greater than 600 MPa;
- it has a mean anisotropy coefficient r of greater than 1.1;
- it has a mean anisotropy coefficient r of greater than 1.3;
- it furthermore contains between 1% and 10% martensite;
- it furthermore contains between 5% and 8% martensite.
- Finally, the third subject of the invention is a steel strip according to the invention for the production of automobile parts by deep drawing.
- The process according to the invention consists in hot rolling a slab of specific composition and then in coiling the hot-rolled strip obtained at a temperature of between 550 and 850° C.
- This high-temperature coiling operation is favorable to the development of what is called a texture, that is to say an anisotropic structure. This is because such a coiling operation makes it possible for the Fe3C cementite precipitates to coalesce and to reduce the amount of carbon going back into solution during the anneal, this being detrimental to the development of the recrystallization texture.
- The process then consists in cold rolling the strip with a reduction ratio of between 60 and 90% and then in annealing the strip continuously in the intercritical range.
- The intercritical anneal allows most of the carbide phases formed during the coiling after the recrystallization to be redissolved. The fact that the austenization and the dissolution of the carbide phases take place after the recrystallization makes it possible to retain the carbon trapped during the recrystallization and to free it once the recrystallized ferrite texture has developed. The texture will therefore be unaffected by the carbon in solid solution, as is the case with low-temperature coiling, but is only impaired by the isotropic character of the martensite formed.
- The process then consists in cooling the strip down to the ambient temperature, in one or more steps, the cooling rate between 600° C. and the ambient temperature being between 100° C./s and 1500° C./s, and optionally in tempering it at a temperature below 300° C.
- This rapid cooling step allows martensite to form in the structure of the steel, thereby achieving very good mechanical properties. However, measures must be taken to ensure that too much martensite does not form, as martensite is isotropic and therefore reduces the mean anisotropy coefficient r.
- Water quenching allows substantial proportions of carbide phases to be formed in the composition in question. It is possible to reduce the amount of martensitic phase formed by lowering the soak temperature toward lower values in the intercritical range, or else by carrying out a slow cooling operation before the quench.
- It is also possible to reduce the difference in hardness between the ferritic matrix and the martensitic phase, by cooling the strip more slowly or by performing a short tempering operation, lasting around one minute, on the martensitic phase formed after the water quench.
- It should be noted that this tempering operation is in no case an averaging treatment, as is found in the prior art. This is because these averaging treatments, which are generally carried out between 300 and 500° C., have in particular the effect of suppressing the martensite, which is an essential element of the present invention. The tempering optionally carried out according to the invention consists in precipitating some of the carbon in solid solution trapped in the martensite, without reducing the proportion of this martensite. The maximum temperature of this tempering operation is 300° C., preferably 250° C. and more particularly preferably 200° C.
- The composition according to the invention includes carbon with a content of between 0.010% and 0.100%. This element is essential for obtaining good mechanical properties but it must not be present in too great an amount, as it would cause an excessive proportion of martensitic phase to be formed.
- It also includes manganese with a content of between 0.050% and 1.0%. Manganese improves the yield strength of the steel, but greatly reduces its ductility. This is why its content is limited.
- The composition also includes chromium with a content of between 0.010% and 1.0%, which helps in the desired martensite formation.
- The composition also includes silicon with a content of between 0.010% and 0.50%. This greatly improves the yield strength of the steel, but slightly reduces its ductility and degrades its coatability.
- The composition also includes phosphorus with a content of between 0.001% and 0.20%, which hardens the microstructure without affecting its texture.
- The composition also includes aluminum with a content of between 0.010% and 0.10%, which prevents aging by nitrogen trapping.
- By way of nonlimiting examples, and so as to better illustrate the invention, two grades of steel were produced. Their compositions, in thousandths of a percent, are given in the following table.
C Mn Cr Si P Al N A 60 600 70 70 20 56 5 B 43 373 76 13 22 56 5.7 - The balance of the compositions consists of iron and inevitable impurities resulting from the smelting.
- Re: yield strength in MPa;
- Rm: tensile strength in MPa;
- r: anisotropy coefficient;
- P: plateau;
- % m: proportion of martensite.
- After production, the two grades were austenized at 1250° C. for one hour, so as to dissolve the aluminum nitrides. The slabs were then hot rolled in such a way that the end-of-rolling temperature was above 900° C., the value of AR3 for both grades being about 870° C.
- The hot-rolled strips were then cooled by water quenching, at a cooling rate of around 25° C./s, until the coiling temperature was reached. Grade A was coiled at 720° C., while one specimen of grade B was coiled at 550° C. and another at 720 ° C.
- The various specimens were then cold rolled so as to achieve a reduction ratio of 75%, then they underwent an annealing treatment at a soak temperature of 750° C. in the case of some specimens and 800° C. in the case of the others. The cooling down to the ambient temperature was then carried out at a rate of around 25° C./s by water quenching.
- Next, the mechanical properties and the anisotropy characteristics of the steels obtained were measured.
- The results are collated in the following table.
Tcoil Tsoak Rm Grade (° C.) (° C.) Direction Re (MPa) (MPa) P (%) r mean r % m A 720 800 T 420 711 0 1.10 0.98 14 L 405 713 0 1.11 45° 425 720 0 0.85 750 T 443 713 0 1.26 1.02 12 L 438 717 0 1.13 45° 451 736 0 0.84 B 720 800 T 432 656 0 1.46 1.27 8 L 430 697 0 1.60 45° 436 668 0 1.01 750 T 454 662 0 2.04 1.37 7 L 457 690 0 1.41 45° 461 677 0 1.01 550 800 T 455 677 0 1.47 1.21 6 L 446 667 0 1.44 45° 472 687 0 0.97 750 T 475 680 0.3 1.46 1.09 5 L 463 668 0.4 1.25 45° 482 697 0.3 0.83 - The overall anisotropy of a steel is determined by the mean normal anisotropy coefficient r:
where rT denotes the value of r measured in the direction transverse to the rolling direction of the strip, rL denotes the value of r measured in the longitudinal or rolling direction of the strip and r45° denotes the value of r measured at 45° to the rolling direction of the strip. - For a coiling temperature of 720° C.,
FIG. 1 shows the relationship between the mean coefficient r and the content of martensite formed %m for grades A and B. It may be seen that the higher the martensite content, the more anisotropic the steel. - It may also be seen that the higher the martensite content, the higher the mechanical properties.
- As an illustration,
FIG. 2 shows the microstructure obtained with grade A, coiled at 720° C. and then annealed at 750° C. in order finally to obtain 12% martensite. The ferrite and the martensite formed can be clearly distinguished in the figure.
Claims (22)
1. A process for producing a cold-rolled ferritic/martensitic dual-phase steel strip, wherein a slab, the chemical composition of which comprises, by weight:
0.010%≦C≦0.100%
0.050%≦Mn≦1.0%
0.010%≦Cr≦1.0%
0.010%≦Si≦0.50%
0.001%≦P≦0.20%
0.010%≦Al≦0.10%
N≦0.010%
the balance being iron and impurities resulting from the smelting, is hot rolled, said process then comprising the steps consisting in:
coiling the hot-rolled strip obtained at a temperature of between 550 and 850° C.; then
cold rolling the strip with a reduction ratio of between 60 and 90%; then
annealing the strip continuously in the intercritical range; and
cooling it down to the ambient temperature in one or more steps, the cooling rate between 600° C. and the ambient temperature being between 100° C./s and 1500° C./s; and
optionally tempering it at a temperature below 300° C.,
the annealing and cooling operations being carried out in such a way that the strip finally contains from 1 to 15% martensite.
2. The process as claimed in claim 1 , wherein the chemical composition of the steel comprises:
0.020%≦C≦0.060%
0.300%≦Mn≦0.500%
0.010%≦Cr≦1.0%
0.010%≦Si≦0.50%
0.010%≦P≦0.100%
0.010%≦Al≦0.10%
N≦0.010%
the balance being iron and impurities resulting from the smelting.
3. The process as claimed in either of claims 1 and 2, wherein the strip is hot rolled at a temperature above 850° C.
4. The process as claimed in any one of claims 1 to 3 , wherein the strip is hot rolled at a temperature of between 550 and 750° C.
5. The process as claimed in any one of claims 1 to 4 , wherein the strip is cold rolled with a reduction ratio of between 70 and 80%.
6. The process as claimed in any one of claims 1 to 5 , wherein the continuous annealing of the cold-rolled strip comprises a temperature rise phase followed by a soak phase at a predetermined temperature.
7. The process as claimed in claim 6 , wherein the soak temperature is between Ac1 and 900° C.
8. The process as claimed in claim 7 , wherein the soak temperature is between 750 and 850° C.
9. The process as claimed in any one of claims 1 to 8 , wherein the cooling down to the ambient temperature comprises a first, slow cooling step between the soak temperature and 600° C., during which the cooling rate is less than 50° C./s, followed by a second cooling step at a higher rate, of between 100° C./s and 1 500° C./s, down to the ambient temperature.
10. The process as claimed in claim 9 , wherein the second cooling step is carried out by water quenching.
11. The process as claimed in any one of claims 1 to 8 , wherein the cooling is carried out in a single operation at a cooling rate of between 100° C./s and 1500° C./s.
12. The process as claimed in claim 11 , wherein the cooling is carried out by water quenching.
13. A cold-rolled ferritic/martensitic dual-phase steel strip, the chemical composition of which comprises, by weight:
0.010%≦C≦0.100%
0.050%≦Mn≦1.0%
0.010%≦Cr≦1.0%
0.010%≦Si≦0.50%
0.001%≦P≦0.20%
0.010%≦Al≦0.10%
N≦0.010%
the balance being iron and impurities resulting from the smelting, the strip furthermore containing between 1% and 15% martensite.
14. The steel strip as claimed in claim 13 , the chemical composition of which furthermore comprises:
0.020%≦C≦0.060%
0.300%≦Mn≦0.500%
0.010%≦Cr≦1.0%
0.010%≦Si≦0.50%
0.010%≦P≦0.100%
0.010%≦Al≦0.10%
N≦0.010%
the balance being iron and impurities resulting from the smelting.
15. The steel strip as claimed in either of claims 13 and 14, which has a tensile strength Rm of greater than 450 MPa.
16. The steel strip as claimed in claim 15 , which has a tensile strength Rm of greater than 500 MPa.
17. The steel strip as claimed in claim 16 , further which has a tensile strength Rm of greater than 600 MPa.
18. The steel strip as claimed in any one of claims 13 to 17 , which has a mean anisotropy coefficient r of greater than 1.1.
19. The steel strip as claimed in claim 18 , further which has a mean anisotropy coefficient r of greater than 1.3.
20. The steel strip as claimed in any one of claims 13 to 19 , which furthermore contains between 1% and 10% martensite.
21. The steel strip as claimed in claim 20 , which furthermore contains between 5% and 8% martensite.
22. The use of a steel strip as claimed in any one of claims 13 to 21 for the production of automobile parts by deep drawing.
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR03/01358 | 2003-02-05 | ||
FR0301358A FR2850671B1 (en) | 2003-02-05 | 2003-02-05 | PROCESS FOR MANUFACTURING A DUAL-PHASE STEEL BAND HAVING A COLD-ROLLED FERRITO-MARTENSITIC STRUCTURE AND A BAND OBTAINED THEREFROM |
PCT/FR2004/000209 WO2004079022A1 (en) | 2003-02-05 | 2004-01-30 | Method of producing a cold-rolled band of dual-phase steel with a ferritic/martensitic structure and band thus obtained |
Publications (1)
Publication Number | Publication Date |
---|---|
US20060144482A1 true US20060144482A1 (en) | 2006-07-06 |
Family
ID=32696392
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/544,206 Abandoned US20060144482A1 (en) | 2003-02-05 | 2004-01-30 | Method of producing a cold-rolled band of dual-phase steel with a ferritic/martensitic structure and band thus obtained |
Country Status (16)
Country | Link |
---|---|
US (1) | US20060144482A1 (en) |
EP (1) | EP1592816B1 (en) |
JP (1) | JP4528769B2 (en) |
KR (1) | KR101091021B1 (en) |
CN (1) | CN100465299C (en) |
BR (1) | BRPI0407236A (en) |
CA (1) | CA2514736C (en) |
ES (1) | ES2831249T3 (en) |
FR (1) | FR2850671B1 (en) |
HU (1) | HUE052206T2 (en) |
MX (1) | MXPA05008189A (en) |
PL (1) | PL206109B1 (en) |
RU (1) | RU2341566C2 (en) |
UA (1) | UA87454C2 (en) |
WO (1) | WO2004079022A1 (en) |
ZA (1) | ZA200505968B (en) |
Cited By (13)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20080289726A1 (en) * | 2004-11-24 | 2008-11-27 | Nucor Corporation | Cold rolled, dual phase, steel sheet and method of manufacturing same |
US20090071575A1 (en) * | 2004-11-24 | 2009-03-19 | Nucor Corporation | Hot rolled dual phase steel sheet, and method of making the same |
US20090071574A1 (en) * | 2004-11-24 | 2009-03-19 | Nucor Corporation | Cold rolled dual phase steel sheet having high formability and method of making the same |
US20090098408A1 (en) * | 2007-10-10 | 2009-04-16 | Nucor Corporation | Complex metallographic structured steel and method of manufacturing same |
US20100043925A1 (en) * | 2006-09-27 | 2010-02-25 | Nucor Corporation | High strength, hot dip coated, dual phase, steel sheet and method of manufacturing same |
WO2014145536A1 (en) * | 2013-03-15 | 2014-09-18 | Am/Ns Calvert Llc | New high strength bake hardenable low alloy steel and process for manufacture thereof |
US20160245367A1 (en) * | 2013-12-04 | 2016-08-25 | Schaeffler Technologies AG & Co. KG | Chain element |
US10378077B2 (en) | 2014-07-03 | 2019-08-13 | Arcelormittal | Method for producing an ultra high strength coated or not coated steel sheet and obtained sheet |
US10612113B2 (en) * | 2013-07-30 | 2020-04-07 | Salzgitter Flachstahl Gmbh | Micro-alloyed high-strength multi-phase steel containing silicon and having a minimum tensile strength of 750 MPA and improved properties and method for producing a strip from said steel |
US11035020B2 (en) | 2015-12-29 | 2021-06-15 | Arcelormittal | Galvannealed steel sheet |
US11155902B2 (en) | 2006-09-27 | 2021-10-26 | Nucor Corporation | High strength, hot dip coated, dual phase, steel sheet and method of manufacturing same |
US11198928B2 (en) | 2011-11-28 | 2021-12-14 | Arcelormittal | Method for producing high silicon dual phase steels with improved ductility |
US11827948B2 (en) | 2015-12-21 | 2023-11-28 | Arcelormittal | Method for producing a high strength coated steel sheet having improved ductility and formability, and obtained coated steel sheet |
Families Citing this family (19)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN101768697B (en) * | 2008-12-31 | 2012-09-19 | 宝山钢铁股份有限公司 | Method for manufacturing oriented silicon steel with one-step cold rolling method |
CN101781739A (en) * | 2010-03-18 | 2010-07-21 | 武汉钢铁(集团)公司 | Automobile cold-rolled dual-phase steel with tensile strength of 500 MPa |
CN102115808B (en) * | 2010-11-17 | 2013-04-24 | 山东钢铁股份有限公司 | Ferrite region rolling temperature control system |
WO2012128272A1 (en) * | 2011-03-22 | 2012-09-27 | 日立金属株式会社 | Method for winding hot-rolled maraging steel strip |
MX363038B (en) * | 2011-07-06 | 2019-03-01 | Nippon Steel & Sumitomo Metal Corp | Method for producing cold-rolled steel sheet. |
JP2013181183A (en) * | 2012-02-29 | 2013-09-12 | Jfe Steel Corp | High strength cold rolled steel sheet having low in-plane anisotropy of yield strength, and method of producing the same |
BR112014025955B1 (en) * | 2012-04-23 | 2018-12-18 | Jfe Steel Corporation | high strength steel plate and method to manufacture the same |
RU2491357C1 (en) * | 2012-05-10 | 2013-08-27 | Федеральное государственное автономное образовательное учреждение высшего профессионального образования "Национальный исследовательский технологический университет "МИСиС" | Method to produce sheet steel |
CN102703815A (en) * | 2012-06-19 | 2012-10-03 | 东北大学 | 600 Mpa grade hot-rolling dual-phase steel and preparation method thereof |
WO2014081776A1 (en) * | 2012-11-20 | 2014-05-30 | Thyssenkrupp Steel Usa, Llc | Process for making cold-rolled dual phase steel sheet |
US9790567B2 (en) | 2012-11-20 | 2017-10-17 | Thyssenkrupp Steel Usa, Llc | Process for making coated cold-rolled dual phase steel sheet |
US20140137990A1 (en) * | 2012-11-20 | 2014-05-22 | Thyssenkrupp Steel Usa, Llc | Process for manufacturing ferritic hot rolled steel strip |
RU2529323C1 (en) * | 2013-06-27 | 2014-09-27 | Открытое акционерное общество "Северсталь" (ОАО "Северсталь") | Manufacturing method of zinc-plated strip for following application of polymer coating |
CN103952523B (en) * | 2014-04-15 | 2016-01-20 | 东北大学 | A kind of continuous annealing method of martensite ferrite dual phase steel cold rolled sheet |
AU2016209040B2 (en) * | 2015-01-23 | 2019-08-15 | Arconic Technologies Llc | Aluminum alloy products |
US10808293B2 (en) | 2015-07-15 | 2020-10-20 | Ak Steel Properties, Inc. | High formability dual phase steel |
WO2017109538A1 (en) * | 2015-12-21 | 2017-06-29 | Arcelormittal | Method for producing a steel sheet having improved strength, ductility and formability |
CN105401071B (en) * | 2015-12-22 | 2017-12-29 | 武汉钢铁有限公司 | A kind of 500MPa levels car Galvanized Dual Phase Steel and production method |
RU2718604C1 (en) * | 2019-11-05 | 2020-04-08 | Публичное акционерное общество "Магнитогорский металлургический комбинат" | Method for production of cold-rolled high-strength rolled products of different strength classes from two-phase ferritic-martensite steel |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3839095A (en) * | 1971-03-27 | 1974-10-01 | Nippon Kokan Kk | Method of making a drawing steel sheet by continuous annealing process including shelf treatment therein |
US4159218A (en) * | 1978-08-07 | 1979-06-26 | National Steel Corporation | Method for producing a dual-phase ferrite-martensite steel strip |
US4336080A (en) * | 1979-12-14 | 1982-06-22 | Nippon Kokan Kabushiki Kaisha | Method for manufacturing high-strength cold-rolled steel strip excellent in press-formability |
US5123969A (en) * | 1991-02-01 | 1992-06-23 | China Steel Corp. Ltd. | Bake-hardening cold-rolled steel sheet having dual-phase structure and process for manufacturing it |
US5405463A (en) * | 1980-10-24 | 1995-04-11 | Nippon Kokan Kabushiki Kaisha | Continuous annealing process of producing cold rolled mild steel sheet excellent in deep drawability and aging resistibility |
Family Cites Families (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP3370875B2 (en) * | 1996-11-18 | 2003-01-27 | 株式会社神戸製鋼所 | High strength steel sheet excellent in impact resistance and method for producing the same |
TW426742B (en) * | 1997-03-17 | 2001-03-21 | Nippon Steel Corp | Dual-phase type high strength steel sheets having high impact energy absorption properties and a method of producing the same |
JPH10317096A (en) * | 1997-03-17 | 1998-12-02 | Nippon Steel Corp | High strength steel sheet for automobile use, excellent in collision-proof stability, and its production |
JP3936440B2 (en) * | 1997-08-06 | 2007-06-27 | 新日本製鐵株式会社 | High-strength steel sheet for automobiles with excellent collision safety and formability and its manufacturing method |
JP3899680B2 (en) * | 1998-05-29 | 2007-03-28 | Jfeスチール株式会社 | Paint bake-hardening type high-tensile steel sheet and manufacturing method thereof |
JP3793350B2 (en) * | 1998-06-29 | 2006-07-05 | 新日本製鐵株式会社 | Dual-phase high-strength cold-rolled steel sheet with excellent dynamic deformation characteristics and manufacturing method thereof |
EP1571230B1 (en) * | 2000-02-29 | 2006-12-13 | JFE Steel Corporation | High tensile strength cold rolled steel sheet having excellent strain age hardening characteristics and the production thereof |
JP4517525B2 (en) * | 2001-03-14 | 2010-08-04 | Jfeスチール株式会社 | Manufacturing method of low yield ratio steel for low temperature |
-
2003
- 2003-02-05 FR FR0301358A patent/FR2850671B1/en not_active Expired - Lifetime
-
2004
- 2004-01-30 BR BR0407236-7A patent/BRPI0407236A/en active IP Right Grant
- 2004-01-30 ES ES04706710T patent/ES2831249T3/en not_active Expired - Lifetime
- 2004-01-30 RU RU2005127577/02A patent/RU2341566C2/en active
- 2004-01-30 UA UAA200508475A patent/UA87454C2/en unknown
- 2004-01-30 PL PL377834A patent/PL206109B1/en unknown
- 2004-01-30 JP JP2006505664A patent/JP4528769B2/en not_active Expired - Lifetime
- 2004-01-30 EP EP04706710.3A patent/EP1592816B1/en not_active Expired - Lifetime
- 2004-01-30 KR KR1020057014238A patent/KR101091021B1/en active IP Right Grant
- 2004-01-30 CA CA2514736A patent/CA2514736C/en not_active Expired - Lifetime
- 2004-01-30 HU HUE04706710A patent/HUE052206T2/en unknown
- 2004-01-30 WO PCT/FR2004/000209 patent/WO2004079022A1/en active Search and Examination
- 2004-01-30 US US10/544,206 patent/US20060144482A1/en not_active Abandoned
- 2004-01-30 MX MXPA05008189A patent/MXPA05008189A/en active IP Right Grant
- 2004-01-30 CN CNB2004800034661A patent/CN100465299C/en not_active Expired - Lifetime
-
2005
- 2005-07-25 ZA ZA200505968A patent/ZA200505968B/en unknown
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3839095A (en) * | 1971-03-27 | 1974-10-01 | Nippon Kokan Kk | Method of making a drawing steel sheet by continuous annealing process including shelf treatment therein |
US4159218A (en) * | 1978-08-07 | 1979-06-26 | National Steel Corporation | Method for producing a dual-phase ferrite-martensite steel strip |
US4336080A (en) * | 1979-12-14 | 1982-06-22 | Nippon Kokan Kabushiki Kaisha | Method for manufacturing high-strength cold-rolled steel strip excellent in press-formability |
US5405463A (en) * | 1980-10-24 | 1995-04-11 | Nippon Kokan Kabushiki Kaisha | Continuous annealing process of producing cold rolled mild steel sheet excellent in deep drawability and aging resistibility |
US5123969A (en) * | 1991-02-01 | 1992-06-23 | China Steel Corp. Ltd. | Bake-hardening cold-rolled steel sheet having dual-phase structure and process for manufacturing it |
Cited By (24)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20080289726A1 (en) * | 2004-11-24 | 2008-11-27 | Nucor Corporation | Cold rolled, dual phase, steel sheet and method of manufacturing same |
US20090071575A1 (en) * | 2004-11-24 | 2009-03-19 | Nucor Corporation | Hot rolled dual phase steel sheet, and method of making the same |
US20090071574A1 (en) * | 2004-11-24 | 2009-03-19 | Nucor Corporation | Cold rolled dual phase steel sheet having high formability and method of making the same |
US7879160B2 (en) | 2004-11-24 | 2011-02-01 | Nucor Corporation | Cold rolled dual-phase steel sheet |
US7959747B2 (en) | 2004-11-24 | 2011-06-14 | Nucor Corporation | Method of making cold rolled dual phase steel sheet |
US8337643B2 (en) | 2004-11-24 | 2012-12-25 | Nucor Corporation | Hot rolled dual phase steel sheet |
US8366844B2 (en) | 2004-11-24 | 2013-02-05 | Nucor Corporation | Method of making hot rolled dual phase steel sheet |
US11155902B2 (en) | 2006-09-27 | 2021-10-26 | Nucor Corporation | High strength, hot dip coated, dual phase, steel sheet and method of manufacturing same |
US20100043925A1 (en) * | 2006-09-27 | 2010-02-25 | Nucor Corporation | High strength, hot dip coated, dual phase, steel sheet and method of manufacturing same |
US20090098408A1 (en) * | 2007-10-10 | 2009-04-16 | Nucor Corporation | Complex metallographic structured steel and method of manufacturing same |
US9157138B2 (en) | 2007-10-10 | 2015-10-13 | Nucor Corporation | Complex metallographic structured high strength steel and method of manufacturing |
US8435363B2 (en) | 2007-10-10 | 2013-05-07 | Nucor Corporation | Complex metallographic structured high strength steel and manufacturing same |
US11198928B2 (en) | 2011-11-28 | 2021-12-14 | Arcelormittal | Method for producing high silicon dual phase steels with improved ductility |
WO2014145536A1 (en) * | 2013-03-15 | 2014-09-18 | Am/Ns Calvert Llc | New high strength bake hardenable low alloy steel and process for manufacture thereof |
US10612113B2 (en) * | 2013-07-30 | 2020-04-07 | Salzgitter Flachstahl Gmbh | Micro-alloyed high-strength multi-phase steel containing silicon and having a minimum tensile strength of 750 MPA and improved properties and method for producing a strip from said steel |
US20160245367A1 (en) * | 2013-12-04 | 2016-08-25 | Schaeffler Technologies AG & Co. KG | Chain element |
US11035436B2 (en) * | 2013-12-04 | 2021-06-15 | Schaeffler Technologies AG & Co. KG | Chain element |
US11124853B2 (en) | 2014-07-03 | 2021-09-21 | Arcelormittal | Method for producing a ultra high strength coated or not coated steel sheet and obtained sheet |
US11131003B2 (en) | 2014-07-03 | 2021-09-28 | Arcelormittal | Method for producing an ultra high strength coated or not coated steel sheet and obtained sheet |
US11001904B2 (en) | 2014-07-03 | 2021-05-11 | Arcelormittal | Method for producing an ultra high strength coated or not coated steel sheet and obtained sheet |
US10378077B2 (en) | 2014-07-03 | 2019-08-13 | Arcelormittal | Method for producing an ultra high strength coated or not coated steel sheet and obtained sheet |
US11827948B2 (en) | 2015-12-21 | 2023-11-28 | Arcelormittal | Method for producing a high strength coated steel sheet having improved ductility and formability, and obtained coated steel sheet |
US11035020B2 (en) | 2015-12-29 | 2021-06-15 | Arcelormittal | Galvannealed steel sheet |
US11512362B2 (en) | 2015-12-29 | 2022-11-29 | Arcelormittal | Method for producing an ultra high strength galvannealed steel sheet and obtained galvannealed steel sheet |
Also Published As
Publication number | Publication date |
---|---|
FR2850671B1 (en) | 2006-05-19 |
RU2005127577A (en) | 2006-02-10 |
CN1748039A (en) | 2006-03-15 |
ES2831249T3 (en) | 2021-06-08 |
CN100465299C (en) | 2009-03-04 |
CA2514736C (en) | 2012-12-04 |
JP2006520431A (en) | 2006-09-07 |
EP1592816A1 (en) | 2005-11-09 |
PL206109B1 (en) | 2010-07-30 |
FR2850671A1 (en) | 2004-08-06 |
CA2514736A1 (en) | 2004-09-16 |
BRPI0407236A (en) | 2006-01-31 |
HUE052206T2 (en) | 2021-04-28 |
EP1592816B1 (en) | 2020-10-14 |
ZA200505968B (en) | 2006-06-28 |
WO2004079022A1 (en) | 2004-09-16 |
UA87454C2 (en) | 2009-07-27 |
PL377834A1 (en) | 2006-02-20 |
RU2341566C2 (en) | 2008-12-20 |
KR101091021B1 (en) | 2011-12-09 |
JP4528769B2 (en) | 2010-08-18 |
MXPA05008189A (en) | 2005-10-05 |
KR20050095782A (en) | 2005-09-30 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US20060144482A1 (en) | Method of producing a cold-rolled band of dual-phase steel with a ferritic/martensitic structure and band thus obtained | |
US6818074B2 (en) | High-ductility steel sheet excellent in press formability and strain age hardenability, and method for manufacturing the same | |
EP2757171B1 (en) | High-strength hot-dipped galvanized steel sheet having excellent formability and impact resistance, and method for producing same | |
US9464337B2 (en) | High strength steel sheet having excellent hydrogen embrittlement resistance | |
EP1391526A2 (en) | Dual phase steel sheet with good bake-hardening properties | |
EP2053140A1 (en) | High-strength steel sheets and processes for production of the same | |
JP4362318B2 (en) | High strength steel plate with excellent delayed fracture resistance and method for producing the same | |
JP3039842B2 (en) | Hot-rolled and cold-rolled steel sheets for automobiles having excellent impact resistance and methods for producing them | |
JP3301348B2 (en) | Manufacturing method of hot-rolled high-tensile steel sheet | |
CN111406124A (en) | High-strength cold-rolled steel sheet and method for producing same | |
JPH06145894A (en) | High strength hot rolled steel sheet excellent in ductility and delayed fracture resistance and its production | |
JPH0413406B2 (en) | ||
JP3247909B2 (en) | High-strength hot-dip galvanized steel sheet excellent in ductility and delayed fracture resistance and method for producing the same | |
EP2980228B1 (en) | Manufacturing method for steel sheet | |
JP3818025B2 (en) | Method for producing cold-rolled steel sheet with small anisotropy | |
JP2545316B2 (en) | Method for manufacturing high strength cold rolled steel sheet with excellent strength and ductility characteristics | |
JP2981629B2 (en) | Method for manufacturing bake hardenable steel sheet with composite structure excellent in deep drawability | |
JPS63179046A (en) | High-strength sheet metal excellent in workability and season cracking resistance and its production | |
JP3035040B2 (en) | Composite structure bake hardening steel sheet with excellent deep drawability | |
JPH0657336A (en) | Production of high strength galvannealed steel sheet for high working | |
JPH0125381B2 (en) | ||
EP2980227A1 (en) | Steel sheet and method for producing same | |
JPS59123721A (en) | Production of cold rolled steel sheet having excellent processability | |
JPH0625753A (en) | Manufacture of cold rolled steel sheet excellent in deep drawability | |
JPH07242949A (en) | Production of cold rolled steel sheet for deep drawing excellent in baking hardenability |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: USINOR, FRANCE Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:MOULIN, ANTOINE;REEL/FRAME:017691/0468 Effective date: 20050822 |
|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |