US20060011274A1 - Method for producing steel with retained austenite - Google Patents
Method for producing steel with retained austenite Download PDFInfo
- Publication number
- US20060011274A1 US20060011274A1 US10/526,840 US52684005A US2006011274A1 US 20060011274 A1 US20060011274 A1 US 20060011274A1 US 52684005 A US52684005 A US 52684005A US 2006011274 A1 US2006011274 A1 US 2006011274A1
- Authority
- US
- United States
- Prior art keywords
- austenite
- temperature
- carbon
- steel alloy
- martensite
- 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
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
- C21D6/00—Heat treatment of ferrous alloys
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- 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
- 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
- C21D1/19—Hardening; Quenching with or without subsequent tempering by interrupted quenching
-
- 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
- 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
- C21D1/19—Hardening; Quenching with or without subsequent tempering by interrupted quenching
- C21D1/20—Isothermal quenching, e.g. bainitic hardening
-
- 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
- C21D1/19—Hardening; Quenching with or without subsequent tempering by interrupted quenching
- C21D1/22—Martempering
-
- 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
- C21D2211/001—Austenite
-
- 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
-
- 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
Definitions
- the invention is directed to a method for producing steels with microstructures containing retained austenite.
- the difficulty that this invention seeks to address is that of creating a microstructure in steel, (e.g., but not limited to, low carbon sheet steel) that contains austenite at the ambient temperature at which the steel is to be used in some application, typically room temperature.
- austenite usually must be enriched with carbon (or sometimes nitrogen) in order to stabilize it to room temperature. (Actually, it is metastable, and undergoes subsequent transformation to martensite during deformation, a key component of its utility in service.)
- the problem is to enrich some austenite in the microstructure with carbon, by controlling microstructure evolution and carbon partitioning, without having to use a much higher carbon-containing steel, which is usually undesired for reasons such as reduced weldability.
- the present invention recognizes that the carbon partitioning and growth of the body-centered phase are decoupled in martensite transformations and that this decoupling provides a mechanism for controlling the austenite fraction and its carbon concentration (the kinetics of carbon partitioning are separate from the mechanisms of ferrite formation), since the extent of martensite transformation is controlled primarily by temperature only, rather than both time and temperature.
- This new concept provides additional flexibility for implementing more convenient or less costly processing strategies or methodologies for producing steel with retained austenite.
- a steel alloy is subjected to a heating step to produce austenite.
- the temperature to which the alloy is brought during the heating step is selected to achieve either full or partial austenitization.
- the steel alloy is subjected to a quenching step that brings the alloy to a temperature within the temperature range at which martensite is produced.
- the alloy is subjected to a carbon partitioning step by bringing the alloy to a carbon partitioning temperature, i.e., a temperature at which there is substantial carbon mobility.
- a carbon partitioning temperature i.e., a temperature at which there is substantial carbon mobility.
- there is a range of temperatures at which there is substantial carbon mobility there is a range of temperatures at which there is substantial carbon mobility.
- carbon is transferred from the martensite to the austenite to enrich the austenite so that when the alloy is cooled to the ambient application temperature, typically room temperature, the austenite is stable.
- FIG. 1 depicts a time vs. temperature schematic of the conventional transformation induced plasticity (TRIP) steel bainite processing to produce steel with retained austenite;
- TRIP transformation induced plasticity
- FIG. 2 depicts a time vs. temperature schematic of a process for producing steel with retained austenite that comprises a step of partitioning carbon to austenite;
- FIG. 3 depicts the austenite volume fraction for various partition times for a sheet steel.
- the present invention is directed to a process to produce steels with carbon-enriched retained austenite based on a new understanding of the fundamentals of carbon partitioning in martensite/austenite mixtures. It should be appreciated that the process is broadly applicable to steels that contain more than just martensite plus austenite (and indeed the TRIP steels that are used in the following example of the method contain substantial fractions of equiaxed ferrite). It should further be appreciated that although some bainitic transformation of the retained austenite could also occur in parallel with the carbon partitioning step of the present invention, such bainitic transformation processes can be controlled by alloying so as to influence bainite transformation kinetics to provide an additional variant to the microstructures achieved with the process of the present invention.
- the process involves: (a) heating the steel to form austenite (either completely or partially); (b) quenching the steel to a temperature, usually above ambient, that is in the temperature range at which martensite forms (M s to M f , where M s defines the upper temperature boundary of the range and M f defines the lower temperature boundary of the range) to create controlled amounts of martensite and retained austenite; and (c) thermally treating the steel to partition carbon into the austenite, and thereby increase the chemical stability of the austenite.
- the present invention differs profoundly from the conventional quenching and tempering processes. Namely, conventional quenching and tempering processes are designed to temper the martensite, typically combining the available carbon in the form of carbides, and decomposing the retained austenite. Further, there is no intent to partition the carbon to austenite in these treatments. In contrast, in the present invention, formation of iron carbides is intentionally suppressed, and the austenite is intentionally stabilized rather than decomposed.
- the present invention is believed to have potential application wherever carbon-enriched retained austenite offers improved product characteristics.
- Several applications are envisioned, including (1) high strength sheet steel; (2) high strength bar and forging steels; (3) higher carbon steels, such as carburized gears and bearings; and (4) austempered ductile cast iron.
- these types of steel are particularly applicable to ground transportation vehicles.
- TRIP sheet steels are of great current interest for automotive sheet applications and high strength products that make use of controlled amounts of retained austenite, typically on the order of 10% austenite.
- TRIP sheet steel with retained austenite such as that produced by processes that use bainite transformation, typically in excess of 1% carbon (by weight) in the austenite, are capable of undergoing martensite transformation during deformation. This capability provides several advantages that are useful in various applications. For example, TRIP sheet steel with retained austentite has improved formability, and increased energy absorbance (such as would apply to a vehicle collision in automotive application).
- the microstructures for the TRIP sheet steel of this example also contain equiaxed ferrite, along with different amounts of high strength constituents such as bainite and pearlite, which provide various desired properties known to those skilled in the art. It should, however, be appreciated that the present invention does not require any of these additional constituents to realize a TRIP sheet steel with carbon enriched austenite that is stable or metastable at room temperature or an application temperature. Further, to the extent that additional constituents are employed, a greater or lesser number of constituents can be employed and the relative amounts of such constituents can be varied depending on the desired microstructure. Further, the use of additional constituents to achieve desired properties is applicable to steels other than TRIP sheet steel.
- the present process offers an alternative approach to conventional TRIP sheet production, and a method is explained here, to design steel alloys and processing parameters (i.e. especially the temperatures used during the present process), to achieve desired microstructures.
- the range of microstructures available via the present process is also greater than may be achieved via conventional bainitic processing.
- a schematic for the present process is shown in FIG. 2 , which would apply to processing of cold-rolled and coated sheet products that use an annealing process.
- the schematic diagram includes the annealing temperature (AT), the quench temperature (QT), and the partitioning temperature PT.
- AT annealing temperature
- QT quench temperature
- PT partitioning temperature
- an alloy of composition 0.15C is considered, typical of TRIP products where the carbon level is limited somewhat by weldability constraints.
- the alloy might also contain manganese (and possibly other hardenability additions), perhaps 1%, to suppress undesired reactions during cooling, and significantly elevated silicon levels, perhaps 1.5%, to suppress carbide formation.
- manganese and possibly other hardenability additions
- silicon levels perhaps 1.5%, to suppress carbide formation.
- Other elements such as N, Al, S, are also contained in typical sheet steels, but are not considered in detail for this example.
- the annealing step causes recrystallization of the cold-rolled structure, and establishes the initial austenite.
- the annealing temperature can be above the A 3 ,providing full austenitization, or in the intercritical regime between A 1 and A 3 (A 1 being the temperature at which austenite begins to form), providing both ferrite and austenite.
- the amounts of ferrite and austenite, and their carbon concentrations are established by the applicable phase equilibrium at the selected temperature.
- C carbon by weight percentage
- Ni nickel by weight percentage
- Si silicon by weight percentage
- V vanadium by weight percentage
- Mo molybdenum by weight percentage
- W Tungsten by weight percentage.
- the carbon content in ferrite is low, and C ⁇ ⁇ 0 can be used to give an approximate solution for the purpose of illustration in this example. At 810° C. in the 0.15C, 1.0Mn, 1.5Si steel, about 78% ferrite, plus 22% austenite, are anticipated.
- M s and M f define the temperature range over which martensite forms. See FIG. 2 .
- the M s temperature is about 456° C., although for austenite at an intercritical annealing temperature of 810° C. (C ⁇ ⁇ 68%), the M s temperature is about 355° C.
- Constrained paraequilibrium defines the endpoint of carbon partitioning in the absence of either short- or long-range diffusion of iron or substitutional atoms, which applies to martensite/austenite mixtures at low temperatures where the ⁇ / ⁇ interface is stationary.
- the recently developed CPE theory indicates that the austenite in the present example could be enriched in carbon to a level of approximately 1.5% at a partitioning temperature (PT) of about 450° C., write the martensite is depleted to quite low carbon levels.
- PT partitioning temperature
- the essence of the CPE theory involves a condition where the chemical potential of carbon is equal in the ⁇ and ⁇ phases, in the absence of substantial carbide formation, and the ⁇ / ⁇ interface is effectively stationary, i.e. constrained, at usual partitioning temperatures.)
- the austenite is stable after final cooling to room temperature.
- the partitioning kinetics are also temperature dependent, but suitable partitioning should be able to be accomplished under time/temperature conditions that are usually employed for bainitic transformation (the required time is also dependent upon microstructural and other factors).
- bainitic ferrite growth in addition to carbon partitioning is required for conventional bainitic processing.
- the steel composition and processing parameters used here produce a final microstructure of 78% equiaxed ferrite, 12% carbon-depleted martensite, and 10% retained austenite (having approximately 1.5% carbon).
- Such a microstructure is expected to represent a commercially viable TRIP product.
- other microstructure variants can be designed by altering the steel composition and critical processing parameters. Some of these microstructures would be difficult to achieve by conventional processing, and the new process allows the potential for higher levels of carbon enrichment in the austenite, increasing strength via formation of lath martensite in the microstructure, and application to Si/Al-containing iron castings.
- Example results are shown in FIG. 3 , obtained for a 0.19C, 1.46Mn, 1.96Al sheet steel., intercritically annealed for 180 s at 805° C. to create a ferrite/austenite starting microstructure, followed by quenching to 284° C., and then partitioning for various times and temperatures (between 300 and 450° C.) shown in the figure. The final austenite fraction after complete processing is shown. This example shows that substantial quantities of retained austenite are achieved by Q&P processing, where the quenching temperature was carefully selected to control the transformed microstructure prior to quenching.
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Heat Treatment Of Sheet Steel (AREA)
Abstract
The present invention relates to a process for producing steel with retained austenite. In one embodiment, the process comprises the steps of heating a steel alloy to produce austenite, quenching the steel to produce martensite, and carbon partitioning to transfer carbon from the martensite to the austenite.
Description
- The invention is directed to a method for producing steels with microstructures containing retained austenite.
- The difficulty that this invention seeks to address is that of creating a microstructure in steel, (e.g., but not limited to, low carbon sheet steel) that contains austenite at the ambient temperature at which the steel is to be used in some application, typically room temperature. Without substantial additions of expensive alloying elements such as nickel, austenite usually must be enriched with carbon (or sometimes nitrogen) in order to stabilize it to room temperature. (Actually, it is metastable, and undergoes subsequent transformation to martensite during deformation, a key component of its utility in service.) The problem is to enrich some austenite in the microstructure with carbon, by controlling microstructure evolution and carbon partitioning, without having to use a much higher carbon-containing steel, which is usually undesired for reasons such as reduced weldability.
- Previous attempts have been made to solve this problem by controlling alloying and processing to effect a bainitic phase transformation, suppressing cementite formation, and retaining carbon-enriched austenite. Most often, processing of these steels involves intercritical annealing to form a microstructure at high temperature that consists of both carbon-depleted ferrite and (somewhat) carbon enriched austenite, which is further enriched through carbon partitioning during formation of bainitic ferrite in carefully selected alloys. A limitation of this approach is the processing constraint that is needed to control the bainite transformation. The time/temperature/alloying approaches are quite challenging, especially to match with the thermal characteristics of commercial processing facilities. In the case of bainite transformations, carbon partitioning and growth of the body-centered phase are coupled.
- Conventional processing of cold-rolled TRIP sheet steels to produce retained austenite that uses the bainitic transformation is typically performed in continuous annealing or hot-dip coating lines, according to the simplified thermal process schematic shown in
FIG. 1 . Intercritical annealing is conducted to recrystallize the cold-rolled ferrite, and to create controlled amounts of ferrite and austenite in the microstructure. The austenite is cooled from the intercritical annealing temperature (IAT) to the bainitic transformation temperature (BTT), where it decomposes to bainitic ferrite and carbon-enriched austenite. Special alloying additions, typically silicon, aluminum, or phosphorus, are made to suppress carbide formation during the bainite transformation. During final cooling, some martensite may form, but if sufficient carbon-enrichment of the austenite is achieved, then significant amounts of austenite can be retained, resulting in the desired TRIP microstructure. - The present invention recognizes that the carbon partitioning and growth of the body-centered phase are decoupled in martensite transformations and that this decoupling provides a mechanism for controlling the austenite fraction and its carbon concentration (the kinetics of carbon partitioning are separate from the mechanisms of ferrite formation), since the extent of martensite transformation is controlled primarily by temperature only, rather than both time and temperature. This new concept provides additional flexibility for implementing more convenient or less costly processing strategies or methodologies for producing steel with retained austenite.
- In one embodiment of the method, a steel alloy is subjected to a heating step to produce austenite. The temperature to which the alloy is brought during the heating step is selected to achieve either full or partial austenitization. Subsequent to the heating step, the steel alloy is subjected to a quenching step that brings the alloy to a temperature within the temperature range at which martensite is produced. Subsequent to the quenching step, the alloy is subjected to a carbon partitioning step by bringing the alloy to a carbon partitioning temperature, i.e., a temperature at which there is substantial carbon mobility. Typically, there is a range of temperatures at which there is substantial carbon mobility. Within this temperature range, carbon is transferred from the martensite to the austenite to enrich the austenite so that when the alloy is cooled to the ambient application temperature, typically room temperature, the austenite is stable.
-
FIG. 1 depicts a time vs. temperature schematic of the conventional transformation induced plasticity (TRIP) steel bainite processing to produce steel with retained austenite; -
FIG. 2 depicts a time vs. temperature schematic of a process for producing steel with retained austenite that comprises a step of partitioning carbon to austenite; and -
FIG. 3 depicts the austenite volume fraction for various partition times for a sheet steel. - The present invention is directed to a process to produce steels with carbon-enriched retained austenite based on a new understanding of the fundamentals of carbon partitioning in martensite/austenite mixtures. It should be appreciated that the process is broadly applicable to steels that contain more than just martensite plus austenite (and indeed the TRIP steels that are used in the following example of the method contain substantial fractions of equiaxed ferrite). It should further be appreciated that although some bainitic transformation of the retained austenite could also occur in parallel with the carbon partitioning step of the present invention, such bainitic transformation processes can be controlled by alloying so as to influence bainite transformation kinetics to provide an additional variant to the microstructures achieved with the process of the present invention.
- Generally, the process involves: (a) heating the steel to form austenite (either completely or partially); (b) quenching the steel to a temperature, usually above ambient, that is in the temperature range at which martensite forms (Ms to Mf, where Ms defines the upper temperature boundary of the range and Mf defines the lower temperature boundary of the range) to create controlled amounts of martensite and retained austenite; and (c) thermally treating the steel to partition carbon into the austenite, and thereby increase the chemical stability of the austenite.
- From a metallurgical perspective, it should be appreciated that the present invention differs profoundly from the conventional quenching and tempering processes. Namely, conventional quenching and tempering processes are designed to temper the martensite, typically combining the available carbon in the form of carbides, and decomposing the retained austenite. Further, there is no intent to partition the carbon to austenite in these treatments. In contrast, in the present invention, formation of iron carbides is intentionally suppressed, and the austenite is intentionally stabilized rather than decomposed.
- The present invention is believed to have potential application wherever carbon-enriched retained austenite offers improved product characteristics. Several applications are envisioned, including (1) high strength sheet steel; (2) high strength bar and forging steels; (3) higher carbon steels, such as carburized gears and bearings; and (4) austempered ductile cast iron. Presently, these types of steel are particularly applicable to ground transportation vehicles.
- The present invention is described with respect to the production of retained austenite in one transformation induced plasticity (TRIP) sheet steel. TRIP sheet steels are of great current interest for automotive sheet applications and high strength products that make use of controlled amounts of retained austenite, typically on the order of 10% austenite. TRIP sheet steel with retained austenite, such as that produced by processes that use bainite transformation, typically in excess of 1% carbon (by weight) in the austenite, are capable of undergoing martensite transformation during deformation. This capability provides several advantages that are useful in various applications. For example, TRIP sheet steel with retained austentite has improved formability, and increased energy absorbance (such as would apply to a vehicle collision in automotive application).
- The microstructures for the TRIP sheet steel of this example also contain equiaxed ferrite, along with different amounts of high strength constituents such as bainite and pearlite, which provide various desired properties known to those skilled in the art. It should, however, be appreciated that the present invention does not require any of these additional constituents to realize a TRIP sheet steel with carbon enriched austenite that is stable or metastable at room temperature or an application temperature. Further, to the extent that additional constituents are employed, a greater or lesser number of constituents can be employed and the relative amounts of such constituents can be varied depending on the desired microstructure. Further, the use of additional constituents to achieve desired properties is applicable to steels other than TRIP sheet steel.
- The present process offers an alternative approach to conventional TRIP sheet production, and a method is explained here, to design steel alloys and processing parameters (i.e. especially the temperatures used during the present process), to achieve desired microstructures. The range of microstructures available via the present process is also greater than may be achieved via conventional bainitic processing. A schematic for the present process is shown in
FIG. 2 , which would apply to processing of cold-rolled and coated sheet products that use an annealing process. The schematic diagram includes the annealing temperature (AT), the quench temperature (QT), and the partitioning temperature PT. For this example, an alloy of composition 0.15C is considered, typical of TRIP products where the carbon level is limited somewhat by weldability constraints. The alloy might also contain manganese (and possibly other hardenability additions), perhaps 1%, to suppress undesired reactions during cooling, and significantly elevated silicon levels, perhaps 1.5%, to suppress carbide formation. Other elements such as N, Al, S, are also contained in typical sheet steels, but are not considered in detail for this example. - The annealing step causes recrystallization of the cold-rolled structure, and establishes the initial austenite. The annealing temperature can be above the A3,providing full austenitization, or in the intercritical regime between A1 and A3 (A1 being the temperature at which austenite begins to form), providing both ferrite and austenite. The carbon content of the austenite is important, and is equal to the overall carbon concentration of the steel in the case of full austenitization (i.e. Cγ=Calloy). For annealing in the intercritical regime, the amounts of ferrite and austenite, and their carbon concentrations, are established by the applicable phase equilibrium at the selected temperature. These values, for example, can be calculated in Fe—C binary alloys just using the phase diagram, or the appropriate tie line may be calculated in multicomponent alloys using standard thermodynamic software packages, such as ThermoCalc. Reasonable estimates can also be made using published correlations for the A3 temperature, as shown below in
Equations 1 and 2. For the example 0.15C, 1.0Mn, 1.5Si steel considered here, A3 could be estimated using the expression of Andrews:
A 3(° C.)=910−203√{square root over (C)}−15.2Ni+44.7Si+104V+31.5Mo+13.1W (1)
Where C is carbon by weight percentage, Ni is nickel by weight percentage, Si is silicon by weight percentage, V is vanadium by weight percentage, Mo is molybdenum by weight percentage, and W is Tungsten by weight percentage. The calculated A3 for this steel is about 898° C., but more importantly, at a given intercritical annealing temperature, we can modify the same expression to estimate the carbon content in the austenite via:
where AT is an annealing temperature in the intercritical regime and Cγ is the carbon by weight percentage in the austenite phase. At 810° C. in this steel, the estimated carbon concentration in the austenite is 0.68%. The phase fractions can be estimated using the lever rule:
where fα is the amount of ferrite by weight percentage, Cγ is the carbon by weight percentage in the austenite phase, fγ is the amount of austenite by weight percentage, Cα is carbon by weight percentage in the ferrite phase, and Calloy is the carbon content in the steel overall, by weight percentage. The carbon content in ferrite is low, and Cα˜0 can be used to give an approximate solution for the purpose of illustration in this example. At 810° C. in the 0.15C, 1.0Mn, 1.5Si steel, about 78% ferrite, plus 22% austenite, are anticipated. - During the quenching step, which occurs after the annealing step, the ferrite remains essentially unchanged and the austenite transforms partially to martensite, depending on the relationship between the quenching temperature (QT), and the Ms temperature of the remaining austenite. Ms and Mf define the temperature range over which martensite forms. See
FIG. 2 . The Ms temperature can be estimated using another correlation of Andrews:
M s (° C.)=539−423C−30.4Mn−12.1Cr−17.7Ni−7.5Mo (5)
where C is carbon by weight percentage, Mn is manganese by weight percentage, Cr is chromium by weight percentage, Ni is nickel by weight percentage, and Mo is molybdenum by weight percentage. For a fully austenitized steel of this composition (Cγ=0.15%), the Ms temperature is about 456° C., although for austenite at an intercritical annealing temperature of 810° C. (Cγ˜68%), the Ms temperature is about 355° C. - Conventional bainitic processing of these steels is normally conducted at temperatures of about 400° C. or somewhat higher, and thus martensite formation is usually precluded. If quenching is carried out to a temperature below Ms, however, then controlled amounts of martensite and retained austenite can be obtained. The expression of Koistinen and Marburger, for the purpose this example, can be modified to estimate the transformed martensite fraction (fm):
f m =f γ AT(1−e −1.1×10−1 (M,−TD) ) (6)
where fγ AT is the amount of austenite just prior to quenching, i.e. 22% in this example. For this example, if the quench temperature is 150° C., then about 12% martensite is formed during the quench, along with the remaining 10% austenite, and 78% equiaxed ferrite. - Following the quenching step, the steel is subjected to a carbon partitioning step to transfer carbon from the martensite to the austenite, thereby stabilizing the steel prior to final cooling to room temperature. The maximum amount of carbon enrichment that can be obtained during the partitioning treatment is given by the “constrained paraequilibrium” (or CPE) condition. Constrained paraequilibrium defines the endpoint of carbon partitioning in the absence of either short- or long-range diffusion of iron or substitutional atoms, which applies to martensite/austenite mixtures at low temperatures where the α/γ interface is stationary. The recently developed CPE theory indicates that the austenite in the present example could be enriched in carbon to a level of approximately 1.5% at a partitioning temperature (PT) of about 450° C., wiile the martensite is depleted to quite low carbon levels. (The essence of the CPE theory involves a condition where the chemical potential of carbon is equal in the α and γ phases, in the absence of substantial carbide formation, and the α/γ interface is effectively stationary, i.e. constrained, at usual partitioning temperatures.) At this level of carbon enrichment, the austenite is stable after final cooling to room temperature. The partitioning kinetics are also temperature dependent, but suitable partitioning should be able to be accomplished under time/temperature conditions that are usually employed for bainitic transformation (the required time is also dependent upon microstructural and other factors). In the present process, only carbon partitioning is required during this treatment, whereas bainitic ferrite growth in addition to carbon partitioning is required for conventional bainitic processing. Thus, for this example, the steel composition and processing parameters used here produce a final microstructure of 78% equiaxed ferrite, 12% carbon-depleted martensite, and 10% retained austenite (having approximately 1.5% carbon). Such a microstructure is expected to represent a commercially viable TRIP product. Using the present process, other microstructure variants can be designed by altering the steel composition and critical processing parameters. Some of these microstructures would be difficult to achieve by conventional processing, and the new process allows the potential for higher levels of carbon enrichment in the austenite, increasing strength via formation of lath martensite in the microstructure, and application to Si/Al-containing iron castings.
- Example results are shown in
FIG. 3 , obtained for a 0.19C, 1.46Mn, 1.96Al sheet steel., intercritically annealed for 180 s at 805° C. to create a ferrite/austenite starting microstructure, followed by quenching to 284° C., and then partitioning for various times and temperatures (between 300 and 450° C.) shown in the figure. The final austenite fraction after complete processing is shown. This example shows that substantial quantities of retained austenite are achieved by Q&P processing, where the quenching temperature was carefully selected to control the transformed microstructure prior to quenching.
Claims (8)
1. A method for producing a steel alloy with retained austenite comprising the acts of:
providing a steel alloy;
annealing, following said step of providing, said steel alloy at an annealing temperature to produce austenite in said steel alloy;
quenching, following said step of annealing, said steel alloy at a temperature to transform at least a portion of said austenite into martensite;
carbon partitioning, following said step of annealing, said steel alloy to transfer carbon from said martensite to said austenite; and
cooling, following said step of carbon partitioning, said steel alloy to a desired temperature.
2. A method, as claimed in claim 1 , wherein:
said step of providing comprising providing a low-carbon steel alloy.
3. A method, as claimed in claim 1 , wherein:
said step of annealing comprising placing said steel alloy at a temperature greater than a temperature for full austenization.
4. A method, as claimed in claim 1 , wherein:
said step of annealing comprising placing said steel alloy at an intercritical temperature that is at or above the temperature at which austenite begins to form and below the temperature for full austenization.
5. A method, as claimed in claim 1 , wherein:
said step of quenching comprising placing said steel alloy at a temperature below the temperature at which martensite starts to form.
6. A method, as claimed in claim 1 , wherein:
said step of quenching comprising placing said steel alloy at a temperature at which martensite forms.
7. A method, as claimed in claim 1 , wherein:
said step of carbon partitioning comprising placing said steel alloy at a temperature at which there is carbon mobility.
8. A method, as claimed in claim 1 , wherein:
said step of carbon partitioning comprising placing said steel alloy at a temperature above which martensite starts to form.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US10/526,840 US20060011274A1 (en) | 2002-09-04 | 2003-09-04 | Method for producing steel with retained austenite |
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US31952102P | 2002-09-04 | 2002-09-04 | |
PCT/US2003/027825 WO2004022794A1 (en) | 2002-09-04 | 2003-09-04 | Method for producing steel with retained austenite |
US10/526,840 US20060011274A1 (en) | 2002-09-04 | 2003-09-04 | Method for producing steel with retained austenite |
Publications (1)
Publication Number | Publication Date |
---|---|
US20060011274A1 true US20060011274A1 (en) | 2006-01-19 |
Family
ID=31978079
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/526,840 Abandoned US20060011274A1 (en) | 2002-09-04 | 2003-09-04 | Method for producing steel with retained austenite |
Country Status (3)
Country | Link |
---|---|
US (1) | US20060011274A1 (en) |
AU (1) | AU2003270334A1 (en) |
WO (1) | WO2004022794A1 (en) |
Cited By (34)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20100263771A1 (en) * | 2007-12-20 | 2010-10-21 | Posco | Steel wire rod for bearing steel, manufacturing method of steel wire rod for bearing steel, heat treatment method of steel bearing, steel bearing and soaking method of bearing steel |
CN102337386A (en) * | 2011-11-14 | 2012-02-01 | 湖南华菱湘潭钢铁有限公司 | Production process of high-toughness and ultra-high strength steel and production system thereof |
WO2012113188A1 (en) * | 2011-02-22 | 2012-08-30 | 武汉科技大学 | Nanostructured ultra-strength dual-phase steel and producing method thereof |
WO2013004910A1 (en) | 2011-07-01 | 2013-01-10 | Rautaruukki Oyj | Method for manufacturing a high-strength structural steel and a high-strength structural steel product |
EP2729587A1 (en) * | 2011-07-06 | 2014-05-14 | Gestamp HardTech AB | A method of hot-shaping and hardening a sheet steel blank |
WO2016001700A1 (en) * | 2014-07-03 | 2016-01-07 | Arcelormittal | Method for producing a high strength steel sheet having improved strength, ductility and formability |
WO2016001705A1 (en) * | 2014-07-03 | 2016-01-07 | Arcelormittal | Method for manufacturing a high strength steel sheet having improved formability and ductility and sheet obtained |
WO2016001699A1 (en) * | 2014-07-03 | 2016-01-07 | Arcelormittal | Method for manufacturing a high strength steel sheet having improved formability and sheet obtained |
WO2016001703A1 (en) * | 2014-07-03 | 2016-01-07 | Arcelormittal | Method for manufacturing a high strength steel sheet and sheet obtained by the method |
WO2016001702A1 (en) * | 2014-07-03 | 2016-01-07 | Arcelormittal | Method for producing a high strength coated steel sheet having improved strength, ductility and formability |
JP2016098427A (en) * | 2014-11-26 | 2016-05-30 | 株式会社神戸製鋼所 | High strength high ductility steel sheet |
KR101630976B1 (en) | 2014-12-08 | 2016-06-16 | 주식회사 포스코 | Ultra-high strenth galvanized steel sheet having excellent surface and coating adheision and method for manufacturing thereof |
KR101714930B1 (en) | 2015-12-23 | 2017-03-10 | 주식회사 포스코 | Ultra high strength steel sheet having excellent hole expansion ratio, and method for manufacturing the same |
US9650708B2 (en) | 2011-05-18 | 2017-05-16 | Thyssenkrupp Steel Europe Ag | High-strength flat steel product and method for producing same |
JP2017526818A (en) * | 2014-07-30 | 2017-09-14 | アルセロールミタル | Manufacturing method of high strength billet |
JP2017527691A (en) * | 2014-07-03 | 2017-09-21 | アルセロールミタル | Method for producing ultra-high strength coated or uncoated steel sheet and the resulting steel sheet |
WO2018084685A1 (en) | 2016-11-07 | 2018-05-11 | 주식회사 포스코 | Ultrahigh-strength steel sheet having excellent yield ratio, and manufacturing method therefor |
WO2018110867A1 (en) | 2016-12-16 | 2018-06-21 | 주식회사 포스코 | High strength cold rolled steel plate having excellent yield strength, ductility, and hole expandability, hot dip galvanized steel plate, and method for producing same |
CN109321719A (en) * | 2018-08-14 | 2019-02-12 | 山东建筑大学 | A kind of 800MPa grade Controlled Colling preparation method based on reverted austenite |
KR20190035133A (en) | 2017-09-26 | 2019-04-03 | 주식회사 포스코 | Giga grade ultra high strength cold rolled steel sheet having excellent elongation and method of manufacturing the same |
US10260121B2 (en) | 2017-02-07 | 2019-04-16 | GM Global Technology Operations LLC | Increasing steel impact toughness |
CN109825683A (en) * | 2018-08-14 | 2019-05-31 | 山东建筑大学 | A kind of manganese partition and reverted austenite 800MPa low-carbon Q&P steel Preparation Method |
CN109825690A (en) * | 2018-08-14 | 2019-05-31 | 山东建筑大学 | A method of carbon/manganese-silicon steel comprehensive mechanical property is promoted based on D-Q-P technique |
US10519526B2 (en) | 2014-05-13 | 2019-12-31 | Posco | High-strength cold rolled steel sheet having excellent ductility, hot-dip galvanized steel sheet and method for manufacturing same |
KR20200132338A (en) | 2019-05-17 | 2020-11-25 | 주식회사 포스코 | Ultra-high strength steel sheet having excellent hole-expandability and ductility, and method for manufacturing thereof |
US10995383B2 (en) | 2014-07-03 | 2021-05-04 | Arcelormittal | Method for producing a high strength coated steel sheet having improved strength and ductility and obtained sheet |
WO2021124094A1 (en) | 2019-12-17 | 2021-06-24 | Arcelormittal | Hot rolled and steel sheet and a method of manufacturing thereof |
US11371113B2 (en) | 2016-12-14 | 2022-06-28 | Evonik Operations Gmbh | Hot-rolled flat steel product and method for the production thereof |
WO2022242859A1 (en) | 2021-05-20 | 2022-11-24 | Nlmk Clabecq | Method for manufacturing a high strength steel plate and high strength steel plate |
US11555226B2 (en) | 2014-07-03 | 2023-01-17 | Arcelormittal | Method for producing a high strength steel sheet having improved strength and formability and obtained sheet |
WO2023090736A1 (en) | 2021-11-19 | 2023-05-25 | 주식회사 포스코 | Cold rolled steel sheet and manufacturing method therefor |
US11920209B2 (en) | 2018-03-08 | 2024-03-05 | Northwestern University | Carbide-free bainite and retained austenite steels, producing method and applications of same |
WO2024132987A1 (en) | 2022-12-18 | 2024-06-27 | Tata Steel Nederland Technology B.V. | Method for producing a hot-rolled high-strength structural steel with improved formability and a method of producing the same |
US12054799B2 (en) | 2015-12-21 | 2024-08-06 | Arcelormittal | Method for producing a high strength steel sheet having improved ductility and formability, and obtained steel sheet |
Families Citing this family (21)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN100415902C (en) * | 2006-08-03 | 2008-09-03 | 上海交通大学 | Method of improving steel object surface hardness using carbon distribution |
KR101070154B1 (en) * | 2008-09-05 | 2011-10-05 | 주식회사 포스코 | Steel wire rod for bearing steel, manufacturing method of steel wire rod for bearing steel, heat treatment method of steel bearing, steel bearing and soaking method of bearing steel |
DE102010003997A1 (en) | 2010-01-04 | 2011-07-07 | Benteler Automobiltechnik GmbH, 33102 | Use of a steel alloy |
CN102002558B (en) * | 2010-11-26 | 2012-07-25 | 清华大学 | Step quenching-distribution heat treatment technology of steels containing carbide formation inhibiting elements |
BR112014006360A2 (en) | 2011-09-20 | 2017-04-04 | Bekaert Sa Nv | tempered and partitioned high carbon steel wire |
US8518195B2 (en) | 2012-01-20 | 2013-08-27 | GM Global Technology Operations LLC | Heat treatment for producing steel sheet with high strength and ductility |
CN102560023A (en) * | 2012-03-01 | 2012-07-11 | 哈尔滨工业大学 | Thermal treatment method for low-carbon chrome-silicon manganese low alloy steel |
CN102660712B (en) * | 2012-06-08 | 2014-07-30 | 中兴能源装备股份有限公司 | Improved 30CrMnSi steel |
CN102876981A (en) * | 2012-10-17 | 2013-01-16 | 夏雨 | Method for preparing medium and low carbon chrome-silicon-manganese martensite cast steel with hardening surface layer |
KR20190101504A (en) * | 2013-05-17 | 2019-08-30 | 에이케이 스틸 프로퍼티즈 인코포레이티드 | High strength steel exhibiting good ductility and method of production via quenching and partitioning treatment by zinc bath |
CN103343191A (en) * | 2013-07-22 | 2013-10-09 | 哈尔滨工业大学 | Two-step isothermal heat treatment method for strengthening and toughening medium carbon-manganese-vanadium low alloy steel |
CN103394573A (en) * | 2013-08-02 | 2013-11-20 | 上海交通大学 | Hot stamping forming process based on Q&P one-step method |
WO2016001708A1 (en) * | 2014-07-03 | 2016-01-07 | Arcelormittal | Method for producing a high strength coated steel sheet having improved strength, formability and obtained sheet |
WO2016001701A1 (en) | 2014-07-03 | 2016-01-07 | Arcelormittal | Polyvalent processing line for heat treating and hot dip coating a steel strip |
CN105018843B (en) * | 2015-08-03 | 2017-03-08 | 北京科技大学 | Vanadium and titanium are combined the Q&P steel of interpolation and its manufacture method |
CN105385835B (en) * | 2015-12-11 | 2017-10-27 | 上海交通大学 | A kind of heat treatment method for improving the high-strength steel part obdurability of cut deal |
WO2017109539A1 (en) | 2015-12-21 | 2017-06-29 | Arcelormittal | Method for producing a high strength steel sheet having improved strength and formability, and obtained high strength steel sheet |
WO2017109538A1 (en) * | 2015-12-21 | 2017-06-29 | Arcelormittal | Method for producing a steel sheet having improved strength, ductility and formability |
CA3009294C (en) | 2015-12-29 | 2022-06-21 | Arcelormittal | Method for producing a ultra high strength galvannealed steel sheet and obtained galvannealed steel sheet |
CN106424280B (en) * | 2016-11-30 | 2017-09-29 | 华中科技大学 | A kind of high-strength steel hot forming differentiation mechanical property distribution flexible control method |
CN107597962A (en) * | 2017-08-15 | 2018-01-19 | 上海交通大学 | A kind of drop stamping and the integrated technique of die trimming |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4544422A (en) * | 1984-04-02 | 1985-10-01 | General Motors Corporation | Ferrite-austenite dual phase steel |
US5618355A (en) * | 1994-04-26 | 1997-04-08 | Nippon Steel Corporation | High-strength steel sheet suitable for deep drawing and process for producing the same |
US6319338B1 (en) * | 1996-11-28 | 2001-11-20 | Nippon Steel Corporation | High-strength steel plate having high dynamic deformation resistance and method of manufacturing the same |
-
2003
- 2003-09-04 AU AU2003270334A patent/AU2003270334A1/en not_active Abandoned
- 2003-09-04 WO PCT/US2003/027825 patent/WO2004022794A1/en not_active Application Discontinuation
- 2003-09-04 US US10/526,840 patent/US20060011274A1/en not_active Abandoned
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4544422A (en) * | 1984-04-02 | 1985-10-01 | General Motors Corporation | Ferrite-austenite dual phase steel |
US5618355A (en) * | 1994-04-26 | 1997-04-08 | Nippon Steel Corporation | High-strength steel sheet suitable for deep drawing and process for producing the same |
US6319338B1 (en) * | 1996-11-28 | 2001-11-20 | Nippon Steel Corporation | High-strength steel plate having high dynamic deformation resistance and method of manufacturing the same |
Cited By (76)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20100263771A1 (en) * | 2007-12-20 | 2010-10-21 | Posco | Steel wire rod for bearing steel, manufacturing method of steel wire rod for bearing steel, heat treatment method of steel bearing, steel bearing and soaking method of bearing steel |
US9593389B2 (en) | 2007-12-20 | 2017-03-14 | Posco | Steel wire rod for bearing steel, manufacturing method of steel wire rod for bearing steel, heat treatment method of steel bearing, steel bearing and soaking method of bearing steel |
WO2012113188A1 (en) * | 2011-02-22 | 2012-08-30 | 武汉科技大学 | Nanostructured ultra-strength dual-phase steel and producing method thereof |
US9650708B2 (en) | 2011-05-18 | 2017-05-16 | Thyssenkrupp Steel Europe Ag | High-strength flat steel product and method for producing same |
WO2013004910A1 (en) | 2011-07-01 | 2013-01-10 | Rautaruukki Oyj | Method for manufacturing a high-strength structural steel and a high-strength structural steel product |
US20140299237A1 (en) * | 2011-07-01 | 2014-10-09 | Rautaruukki Oyj | Method for manufacturing a high-strength structural steel and a high-strength structural steel product |
US9567659B2 (en) * | 2011-07-01 | 2017-02-14 | Rautaruukki Oyj | Method for manufacturing a high-strength structural steel and a high-strength structural steel product |
EP2729587A1 (en) * | 2011-07-06 | 2014-05-14 | Gestamp HardTech AB | A method of hot-shaping and hardening a sheet steel blank |
JP2014524979A (en) * | 2011-07-06 | 2014-09-25 | イェスタムプ・ハードテック・アクチエボラーグ | Method of thermoforming and quenching steel sheet blanks |
EP2729587A4 (en) * | 2011-07-06 | 2015-03-18 | Gestamp Hardtech Ab | A method of hot-shaping and hardening a sheet steel blank |
CN102337386A (en) * | 2011-11-14 | 2012-02-01 | 湖南华菱湘潭钢铁有限公司 | Production process of high-toughness and ultra-high strength steel and production system thereof |
US10519526B2 (en) | 2014-05-13 | 2019-12-31 | Posco | High-strength cold rolled steel sheet having excellent ductility, hot-dip galvanized steel sheet and method for manufacturing same |
US11555226B2 (en) | 2014-07-03 | 2023-01-17 | Arcelormittal | Method for producing a high strength steel sheet having improved strength and formability and obtained sheet |
WO2016001705A1 (en) * | 2014-07-03 | 2016-01-07 | Arcelormittal | Method for manufacturing a high strength steel sheet having improved formability and ductility and sheet obtained |
WO2016001892A3 (en) * | 2014-07-03 | 2016-03-17 | Arcelormittal | Method for manufacturing a high strength steel sheet having improved formability and ductility and sheet obtained |
WO2016001889A3 (en) * | 2014-07-03 | 2016-03-17 | Arcelormittal | Method for manufacturing a high-strength steel sheet and sheet obtained by the method |
WO2016001898A3 (en) * | 2014-07-03 | 2016-03-17 | Arcelormittal | Method for producing a high strength steel sheet having improved strength, ductility and formability |
WO2016001895A3 (en) * | 2014-07-03 | 2016-03-17 | Arcelormittal | Method for producing a high strength coated steel sheet having improved strength, ductility and formability |
US11692235B2 (en) | 2014-07-03 | 2023-07-04 | Arcelormittal | Method for manufacturing a high-strength steel sheet and sheet obtained by the method |
WO2016001702A1 (en) * | 2014-07-03 | 2016-01-07 | Arcelormittal | Method for producing a high strength coated steel sheet having improved strength, ductility and formability |
US11618931B2 (en) | 2014-07-03 | 2023-04-04 | Arcelormittal | Method for producing a high strength steel sheet having improved strength, ductility and formability |
WO2016001703A1 (en) * | 2014-07-03 | 2016-01-07 | Arcelormittal | Method for manufacturing a high strength steel sheet and sheet obtained by the method |
CN106471139A (en) * | 2014-07-03 | 2017-03-01 | 安赛乐米塔尔公司 | Method for manufacturing the coated steel plate of the high intensity with improved intensity, ductility and formability |
KR20170026440A (en) * | 2014-07-03 | 2017-03-08 | 아르셀러미탈 | Method for manufacturing a high-strength steel sheet and sheet obtained by the method |
KR20170026405A (en) * | 2014-07-03 | 2017-03-08 | 아르셀러미탈 | Method for manufacturing a high strength steel sheet having improved formability and sheet obtained |
EP3663415A1 (en) * | 2014-07-03 | 2020-06-10 | ArcelorMittal | Method for producing a high strength steel sheet having improved strength, ductility and formability |
WO2016001699A1 (en) * | 2014-07-03 | 2016-01-07 | Arcelormittal | Method for manufacturing a high strength steel sheet having improved formability and sheet obtained |
CN106574349A (en) * | 2014-07-03 | 2017-04-19 | 安赛乐米塔尔公司 | Method for manufacturing a high strength steel sheet having improved formability and sheet obtained |
CN106661654A (en) * | 2014-07-03 | 2017-05-10 | 安赛乐米塔尔公司 | Method for manufacturing a high-strength steel sheet and sheet obtained by the method |
CN106661703A (en) * | 2014-07-03 | 2017-05-10 | 安赛乐米塔尔公司 | Method for producing a high strength steel sheet having improved strength, ductility and formability |
CN106661650A (en) * | 2014-07-03 | 2017-05-10 | 安赛乐米塔尔公司 | Method for manufacturing a high strength steel sheet having improved formability and ductility and sheet obtained |
WO2016001887A3 (en) * | 2014-07-03 | 2016-03-10 | Arcelormittal | Method for manufacturing a high strength steel sheet having improved formability and sheet obtained |
JP2020045573A (en) * | 2014-07-03 | 2020-03-26 | アルセロールミタル | Method for manufacturing high-strength coated steel sheet having improved strength, ductility and formability |
JP2017527691A (en) * | 2014-07-03 | 2017-09-21 | アルセロールミタル | Method for producing ultra-high strength coated or uncoated steel sheet and the resulting steel sheet |
JP2017527690A (en) * | 2014-07-03 | 2017-09-21 | アルセロールミタル | Method for producing high strength coated steel sheet with improved strength, ductility and formability |
US11492676B2 (en) | 2014-07-03 | 2022-11-08 | Arcelormittal | Method for producing a high strength coated steel sheet having improved strength, ductility and formability |
KR102464730B1 (en) | 2014-07-03 | 2022-11-07 | 아르셀러미탈 | Method for manufacturing a high-strength steel sheet and sheet obtained by the method |
KR102432167B1 (en) | 2014-07-03 | 2022-08-11 | 아르셀러미탈 | Method for manufacturing a high-strength steel sheet and sheet obtained by the method |
RU2677888C2 (en) * | 2014-07-03 | 2019-01-22 | Арселормиттал | Method for manufacturing high strength steel sheet having improved formability and sheet obtained |
KR102423654B1 (en) | 2014-07-03 | 2022-07-20 | 아르셀러미탈 | Method for manufacturing a high strength steel sheet having improved formability and sheet obtained |
RU2680042C2 (en) * | 2014-07-03 | 2019-02-14 | Арселормиттал | Method of manufacturing high-strength steel sheet with improved strength, plasticity and formability |
RU2680043C2 (en) * | 2014-07-03 | 2019-02-14 | Арселормиттал | Method for producing a high-strength steel sheet, having improved formability and ductility, and obtained sheet |
KR20220097546A (en) * | 2014-07-03 | 2022-07-07 | 아르셀러미탈 | Method for manufacturing a high-strength steel sheet and sheet obtained by the method |
EP3831965A1 (en) | 2014-07-03 | 2021-06-09 | ArcelorMittal | Method for producing a high strength coated steel sheet having improved strength, ductility and formability |
RU2686729C2 (en) * | 2014-07-03 | 2019-04-30 | Арселормиттал | Method of producing high-strength steel sheet with coating, having high strength, ductility and moldability |
US10995383B2 (en) | 2014-07-03 | 2021-05-04 | Arcelormittal | Method for producing a high strength coated steel sheet having improved strength and ductility and obtained sheet |
US10844455B2 (en) | 2014-07-03 | 2020-11-24 | Arcelormittal | Method for manufacturing a high strength steel sheet and sheet obtained by the method |
EP3656879A3 (en) * | 2014-07-03 | 2020-07-22 | ArcelorMittal | Method for manufacturing a high-strength steel sheet and sheet obtained by the method |
JP2019178428A (en) * | 2014-07-03 | 2019-10-17 | アルセロールミタル | Method for producing ultra high strength coated or not coated steel sheet and obtained sheet |
US10472692B2 (en) | 2014-07-03 | 2019-11-12 | Arcelormittal | Method for manufacturing a high strength steel sheet having improved formability and ductility and sheet obtained |
WO2016001700A1 (en) * | 2014-07-03 | 2016-01-07 | Arcelormittal | Method for producing a high strength steel sheet having improved strength, ductility and formability |
JP2017526818A (en) * | 2014-07-30 | 2017-09-14 | アルセロールミタル | Manufacturing method of high strength billet |
WO2016084847A1 (en) * | 2014-11-26 | 2016-06-02 | 株式会社神戸製鋼所 | High-strength high-ductility steel sheet |
JP2016098427A (en) * | 2014-11-26 | 2016-05-30 | 株式会社神戸製鋼所 | High strength high ductility steel sheet |
KR101630976B1 (en) | 2014-12-08 | 2016-06-16 | 주식회사 포스코 | Ultra-high strenth galvanized steel sheet having excellent surface and coating adheision and method for manufacturing thereof |
US10344361B2 (en) | 2014-12-08 | 2019-07-09 | Posco | Ultra-high strength, hot-dip galvanized steel sheet having excellent surface quality and coating adhesion |
US12054799B2 (en) | 2015-12-21 | 2024-08-06 | Arcelormittal | Method for producing a high strength steel sheet having improved ductility and formability, and obtained steel sheet |
KR101714930B1 (en) | 2015-12-23 | 2017-03-10 | 주식회사 포스코 | Ultra high strength steel sheet having excellent hole expansion ratio, and method for manufacturing the same |
WO2018084685A1 (en) | 2016-11-07 | 2018-05-11 | 주식회사 포스코 | Ultrahigh-strength steel sheet having excellent yield ratio, and manufacturing method therefor |
US11371113B2 (en) | 2016-12-14 | 2022-06-28 | Evonik Operations Gmbh | Hot-rolled flat steel product and method for the production thereof |
KR101858852B1 (en) | 2016-12-16 | 2018-06-28 | 주식회사 포스코 | Cold-rolled steel sheet and galvanized steel sheet having excelent elonggation, hole expansion ration and yield strength and method for manufacturing thereof |
WO2018110867A1 (en) | 2016-12-16 | 2018-06-21 | 주식회사 포스코 | High strength cold rolled steel plate having excellent yield strength, ductility, and hole expandability, hot dip galvanized steel plate, and method for producing same |
US10260121B2 (en) | 2017-02-07 | 2019-04-16 | GM Global Technology Operations LLC | Increasing steel impact toughness |
KR20190035133A (en) | 2017-09-26 | 2019-04-03 | 주식회사 포스코 | Giga grade ultra high strength cold rolled steel sheet having excellent elongation and method of manufacturing the same |
US11920209B2 (en) | 2018-03-08 | 2024-03-05 | Northwestern University | Carbide-free bainite and retained austenite steels, producing method and applications of same |
CN109321719A (en) * | 2018-08-14 | 2019-02-12 | 山东建筑大学 | A kind of 800MPa grade Controlled Colling preparation method based on reverted austenite |
CN109825690A (en) * | 2018-08-14 | 2019-05-31 | 山东建筑大学 | A method of carbon/manganese-silicon steel comprehensive mechanical property is promoted based on D-Q-P technique |
CN109825683A (en) * | 2018-08-14 | 2019-05-31 | 山东建筑大学 | A kind of manganese partition and reverted austenite 800MPa low-carbon Q&P steel Preparation Method |
KR20200132338A (en) | 2019-05-17 | 2020-11-25 | 주식회사 포스코 | Ultra-high strength steel sheet having excellent hole-expandability and ductility, and method for manufacturing thereof |
WO2021123877A1 (en) | 2019-12-17 | 2021-06-24 | Arcelormittal | Hot rolled steel sheet and method of manufacturing thereof |
WO2021124094A1 (en) | 2019-12-17 | 2021-06-24 | Arcelormittal | Hot rolled and steel sheet and a method of manufacturing thereof |
WO2022243461A1 (en) | 2021-05-20 | 2022-11-24 | Nlmk Clabecq | Method for manufacturing a high strength steel plate and high strength steel plate |
WO2022242859A1 (en) | 2021-05-20 | 2022-11-24 | Nlmk Clabecq | Method for manufacturing a high strength steel plate and high strength steel plate |
KR20230073569A (en) | 2021-11-19 | 2023-05-26 | 주식회사 포스코 | Cold rolled steel sheet having excellent strength and formability and method of manufacturing the same |
WO2023090736A1 (en) | 2021-11-19 | 2023-05-25 | 주식회사 포스코 | Cold rolled steel sheet and manufacturing method therefor |
WO2024132987A1 (en) | 2022-12-18 | 2024-06-27 | Tata Steel Nederland Technology B.V. | Method for producing a hot-rolled high-strength structural steel with improved formability and a method of producing the same |
Also Published As
Publication number | Publication date |
---|---|
AU2003270334A1 (en) | 2004-03-29 |
WO2004022794A1 (en) | 2004-03-18 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US20060011274A1 (en) | Method for producing steel with retained austenite | |
Speer et al. | Carbon partitioning into austenite after martensite transformation | |
CN108474081B (en) | Steel material for press forming, formed member thereof, and heat treatment method | |
EP2683839B1 (en) | Process for producing high strength formable steel and high strength formable steel produced therewith | |
Matlock et al. | Applications of rapid thermal processing to advanced high strength sheet steel developments | |
US4033789A (en) | Method of producing a high strength steel having uniform elongation | |
US8518195B2 (en) | Heat treatment for producing steel sheet with high strength and ductility | |
US20010015245A1 (en) | Flat product, such as sheet, made of steel having a high yield strength and exhibiting good ductility and process for manufacturing this product | |
Sugimoto et al. | Formability of Nb bearing ultra high-strength TRIP-aided sheet steels | |
EP3704276B1 (en) | Press hardened steel with tailored properties after novel thermal treatment | |
EP3298174B1 (en) | Low alloy third generation advanced high strength steel | |
Ding et al. | Heat treatment, microstructure and mechanical properties of a C–Mn–Al–P hot dip galvanizing TRIP steel | |
Speer et al. | Nb-microalloying in next-generation flat-rolled steels: an overview | |
Costa et al. | Dilatometric study of continuous cooling transformation of intercritical austenite in cold rolled AHSS-DP steels | |
US10323307B2 (en) | Process and steel alloys for manufacturing high strength steel components with superior rigidity and energy absorption | |
JPH06271930A (en) | Production of high strength and high toughness steel excellent in fatigue property | |
Akram et al. | High-strength low-cost nano-bainitic steel | |
Jirková et al. | Influence of chromium and niobium on the press-hardening process of multiphase low-alloy TRIP steels | |
Girina et al. | Effect of annealing parameters on austenite decomposition in a continuously annealed dual-phase steel | |
CA1045007A (en) | High strength ductile hot rolled nitrogenized steel | |
Kim et al. | Acceleration of bainitic transformation in 0.28 C-3.8 Mn-1.5 Si steel utilizing chemical heterogeneity | |
Lee et al. | Development of a press-hardened steel suitable for thin slab direct rolling processing | |
Deng et al. | Comparative study on effects of annealing temperature on microstructures and mechanical properties of high-Al low-Si steel | |
Speer et al. | Austenitizing in steels | |
Sahay | Annealing of steel |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: COLORADO SCHOOL OF MINES, COLORADO Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:SPEER, JOHN G.;MATLOCK, DAVID K.;GALLAGHER, MATTHEW F.;REEL/FRAME:014218/0372;SIGNING DATES FROM 20031201 TO 20031206 |
|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |