CN102822371B - Steel sheet with high tensile strength and superior ductility and method for producing same - Google Patents
Steel sheet with high tensile strength and superior ductility and method for producing same Download PDFInfo
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- CN102822371B CN102822371B CN201180016733.9A CN201180016733A CN102822371B CN 102822371 B CN102822371 B CN 102822371B CN 201180016733 A CN201180016733 A CN 201180016733A CN 102822371 B CN102822371 B CN 102822371B
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/001—Ferrous alloys, e.g. steel alloys containing N
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
- C21D8/0226—Hot rolling
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/46—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for sheet metals
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/08—Ferrous alloys, e.g. steel alloys containing nickel
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/12—Ferrous alloys, e.g. steel alloys containing tungsten, tantalum, molybdenum, vanadium, or niobium
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/001—Austenite
Abstract
Disclosed is a steel sheet with high tensile strength and superior ductility having tensile strength of 700 - 900 MPa and capable of avoiding abrupt failure during press molding and method for producing the same. The steel sheet with high tensile strength and superior ductility is characterized by having a composition containing 0.5 - 1.5% C, 0.1% or less Si, 10 - 25% Mn, 0.1% or less P, 0.05% or less S, 0.1% or less Al, 3.0 - 8.0% Ni, 0.1% or less Mo, and 0.01% or less N (% by mass), with the remainder being Fe and unavoidable impurities and by having recrystallized austenite particles with an average particle diameter of 5 - 30 [mu]m or, further, a microstructure formed from another structure with an areal proportion of 1% or less.
Description
Technical field
The high-tensile steel that the ductility of the 700 ~ 900MPa that the present invention relates to automobile that to be high-tensile steel, the particularly tensile strength (TS) used in the industrial field such as Transport Machinery of representative be is excellent and manufacture method thereof.
Background technology
In recent years, from the view point of suppression global warming, the output reducing carbonic acid gas becomes urgent problem, requires the fuel efficiency improving automobile than ever more consumingly.Therefore, positive active research realizes the slimming of component parts by the high tensile of the steel plate as body material thus makes the countermeasure of body lightening.But, the high tensile of steel plate will inevitably cause the reduction of press formability, therefore the exploitation of the steel plate simultaneously with high tensile and good press formability is advanced, in trolley part, adopt the various complex tissue steel plate such as the duplex structure's steel plate be made up of ferrite and martensite or the retained austenite steel plate with phase change induction plasticity so far, serve certain effect.
Recently, determine that the discharge regulation of carbonic acid gas soon will be more strict, the lightweight target extremely High Level of vehicle body.Therefore, for the parts that the shaping difficulty of the steel plate being below 540MPa for using TS is in the past high, also need slimming, the TS being strongly required to have the press formability equal with existing steel plate is the high-tensile steel of 700 ~ 900MPa.
From such situation, have studied the application of high Mn austenitic steel in high-tensile steel that application so far in metal sheet starting material is less.Even if high Mn austenitic steel is at room temperature also using austenite as principal phase, be utilized as non-magnetic steel or Cryogenic Steel in the past, but because austenitic twinning-induced plasticity demonstrates significant work hardening and high ductility, therefore, the novel high ductibility high-tensile steel effectively utilizing this effect is proposed.
Such as, Patent Document 1 discloses a kind of manufacture method of trolley part high tensile hot-rolled steel sheet of excellent processability, wherein, the steel disc with following steel composition is heated to after more than 1100 DEG C, with total rolling rate more than 90% of roughing and finish to gauge, and finishing temperature more than 800 DEG C, final thickness of slab reaches the mode of 1.1 ~ 5.0mm, terminate continuously hot final rolling, then, less than 650 DEG C are cooled to the speed of cooling of 10 ~ 100 DEG C/sec, then batch, wherein, the steel of described steel disc consists of: in % by weight, containing below C:1.0%, Si:0.01 ~ 2.50%, Mn:10 ~ 30%, sol.Al:0.001 ~ 0.10%, below P:0.05%, below S:0.05%, surplus is made up of iron and inevitable impurity.
In addition, Patent Document 2 discloses the excellent high strength light steel band of a kind of cold formability or steel plate, wherein, in mass %, there is below C:1.00%, Mn:7.00 ~ 30.00%, Al:1.00 ~ 10.00%, Si: more than 2.50% and less than 8.00%, Al+Si: more than 3.50% and less than 12.00%, B: be less than 0.01% and Ni as any composition more than 0.00%: be less than 8.00%, Cu: be less than 3.00%, N: be less than 0.60%, Nb: be less than 0.30%, Ti: be less than 0.30%, V: be less than 0.30%, P: be less than 0.01%.
In addition, Patent Document 3 discloses TS more than 900MPa, TS × El (El: elongation at break) more than the Fe-C-Mn series austenite hot-rolled steel sheet of 45000MPa% and TS more than 950MPa, TS × El is more than the Fe-C-Mn series austenite cold-rolled steel sheet of 45000MPa%, there is following composition: in % by weight, containing C:0.5 ~ 0.7%, Mn:17 ~ 24%, below Si:3%, below Al:0.050%, below S:0.030%, below P:0.08%, below N:0.1%, and as optional below Cr:1%, below Mo:0.40%, below Ni:1%, below Cu:5%, below Ti:0.50%, below Nb:0.50%, one or more in the element of below V:0.50%, surplus is made up of Fe and inevitable impurity, recrystallize rate is more than 75%, the area occupation ratio of carbide is less than 1.5%, average austenite grain footpath is less than 18 μm.
In addition, Patent Document 4 discloses the manufacture method of the excellent high Mn non-magnetic steel of a kind of local deformaton ability, wherein, after steel ingot or steel disc are heated to 1050 ~ 1250 DEG C, make finishing temperature be 900 DEG C and carry out hot rolling, described steel ingot or steel disc contain C:0.15 ~ 0.70 % by weight, Si:0.10 ~ 3.00 % by weight, Mn:12 ~ 30 % by weight, Ti:0.01 ~ 0.10 % by weight, surplus is made up of Fe and inevitable impurity, simultaneously about the content of C and Mn, meet 60 × C % by weight+Mn % by weight >=36 % by weight, and about the amount of non-metallic inclusion, cleanliness factor is less than 0.03%.
Prior art document
Patent documentation
Patent documentation 1: Japanese Unexamined Patent Publication 4-259325 publication
Patent documentation 2: Japanese Unexamined Patent Application Publication 2004-521192 publication
Patent documentation 3: Japanese Unexamined Patent Application Publication 2006-528278 publication
Patent documentation 4: Japanese Unexamined Patent Publication 5-171273 publication
Summary of the invention
Invent problem to be solved
But, for the high Mn austenitic steel plate recorded in patent documentation 1 ~ 4, easily there is the so-called plasticity wild effect of Work Hardening Characteristic destabilization in Large strain district, therefore, there is the problem easily unexpectedly rupturing when stamping and necking down does not occur.
The object of the invention is to, the high-tensile steel that the ductility providing burst when can avoid stamping to rupture, have the TS of 700 ~ 900MPa is excellent and manufacture method thereof.
For the method for dealing with problems
The present inventor to achieve these goals, conducts in-depth research repeatedly, found that following opinion.
I) in order to avoid burst fracture time stamping, the local elongation rate (l-El:local elongation) needing the 13B test film specified in use JIS Z2201 to measure is more than 5%.
Ii) in order to make l-El be more than 5%, the Ni of more than 3 quality % is added and to form the microstructure that the recrystallize austenite crystal that is more than 5 μm by median size forms be effective.
The present invention completes based on such opinion, the high-tensile steel that a kind of ductility is excellent is provided, it is characterized in that, there is following one-tenth be grouped into, in mass %, containing C:0.5 ~ 1.5%, below Si:0.1%, Mn:10 ~ 25%, below P:0.1%, below S:0.05%, below Al:0.1%, Ni:3.0 ~ 8.0%, below Mo:0.1%, below N:0.01%, surplus is made up of Fe and inevitable impurity, and there is following microstructure, by median size be 5 ~ 30 μm recrystallize austenite crystal or further count with area occupation ratio less than 1% other organizational compositions.
High-tensile steel of the present invention such as can manufacture as follows, the steel billet with mentioned component composition is reheated to the Heating temperature of 1100 ~ 1300 DEG C, hot rolling is carried out with the finishing temperature of more than 800 DEG C, temperature range below 800 DEG C is cooled at least 600 DEG C with the speed of cooling of more than 20 DEG C/sec, batches with the coiling temperature of less than 600 DEG C.
After batching, carry out descaling further, anneal with the annealing temperature of 750 ~ 1050 DEG C, from annealing temperature until cool with the speed of cooling of more than 10 DEG C/sec in the temperature range of at least 450 DEG C, or, carry out descaling, cold rolling, then, with the annealing temperature of 750 ~ 1050 DEG C annealing, cooling with the speed of cooling of more than 10 DEG C/sec from annealing temperature to the temperature range of at least 450 DEG C.
That is, high-tensile steel of the present invention be steel plate after hot rolling, by the steel plate after the steel plate annealing after hot rolling, by any one steel plate in the steel plate after the cold-rolling of steel plate after hot rolling and after annealing.
Invention effect
According to the present invention, burst fracture when can avoid stamping can be manufactured, there is the excellent high-tensile steel of the ductility of the TS of 700 ~ 900MPa.High-tensile steel of the present invention has excellent strength-ductility balanced, therefore, also can apply in the parts that shaping difficulty is high, be very suitable for the lightweight of body of a motor car.
Embodiment
The high-tensile steel excellent about ductility of the present invention and manufacture method thereof, be described below in detail.It should be noted that, " % " that represent the amount of composition unless otherwise specified, then refers to " quality % ".
1) become to be grouped into
C：0.5~1.5%
C is the element necessary to the stabilization of austenite phase, and the high tensileization for steel also plays larger effect.But when C amount is less than 0.5%, the stabilization of austenite phase becomes insufficient, can not get excellent ductility.On the other hand, when C amount is more than 1.5%, due to the precipitation of carbide, ductility reduces.Therefore, it is 0.5 ~ 1.5% that C is measured, and is preferably 0.5 ~ 1.0%.
Below Si:0.1%
Si can add the deoxidant element for steel.But, as the Si content in steel, add and to cause saturated, the subsurface defect that caused by the increase of inclusion of deoxidation effect and the increase of surface imperfection more than 0.1%.Therefore, making Si measure is less than 0.1%.It should be noted that, in order to obtain deoxidation effect fully, preferably making Si measure is 0.01 ~ 0.1%.
Mn：10~25%
Mn and C is the element necessary to the stabilization of austenite phase equally.But when Mn amount is less than 10%, the stabilization of austenite phase is insufficient, can not get excellent ductility.On the other hand, when Mn amount is more than 25%, the hot workability of steel reduces, the manufacturing of infringement steel plate.Therefore, Mn amount is made to be 10 ~ 25%, to be preferably 15 ~ 25%.And then, in order to the ductility stably realizing being brought by twinning-induced plasticity improves effect, preferably measure and Mn amount with the mode control C meeting following (1) formula.
32≤20×[C]+[Mn]≤36…(1)
Wherein, [C], [Mn] represent the content of C, Mn respectively.
As mentioned above, C and Mn affects the stabilization of austenite phase.Contriver is studied the relation that the stabilization of austenite phase and material behavior, particularly TS × El balance, and find C amount, the Mn amount scope in the application, and when C amount and Mn amount meet (1) formula, particularly TS × El balance is good.Can this is presumably because, 20 × [C]+[Mn] is lower than (1) formula, when being namely less than 32, austenite is mutually unstable, easy generation martensitic transformation, on the other hand, 20 × [C]+[Mn] higher than (1) formula, namely more than 36 time, stacking fault energy becomes too high, twinning-induced plasticity be difficult to occur.
Below P:0.1%
When P amount is more than 0.1%, Gang Toughness reduces.Therefore, it is less than 0.1% that P is measured, and is preferably less than 0.05%.
Below S:0.05%
When S amount is more than 0.05%, the hot workability of steel reduces.Therefore, it is less than 0.05% that S is measured, and is preferably less than 0.02%.Be more preferably less than 0.01%.
Below Al:0.1%
Al is the element of the deoxidation can adding for steel.But, as the Al content in steel, add and can cause the subsurface defect that is saturated, that caused by the increase of inclusion of deoxidation effect and the increase of surface imperfection more than 0.1%.Therefore, making Al measure is less than 0.1%.It should be noted that, in order to obtain deoxidation effect fully, preferably making Al measure is 0.01 ~ 0.1%.
Ni：3.0~8.0%
Ni is most important element in the present invention, has the stacking fault energy of steel is increased, to make manifesting stabilization thus improving the effect of ductility of twinning-induced plasticity.In particular, effective to the suppression of the plasticity destabilization in Large strain district, effective to the raising of the l-El of high Mn austenitic steel plate.In order to fully obtain such effect, needing Ni is measured is more than 3.0%.But when Ni amount is more than 8.0%, this effect is saturated, causes the increase of manufacturing cost simultaneously.Therefore, Ni amount is made to be 3.0 ~ 8.0%, to be preferably 3.0 ~ 6.0%.
Below Mo:0.1%
Mo is made the recrystallize of steel postpone, is contributed to the element of the high tensile of steel by the microminiaturization of austenite crystal.In order to obtain such effect, Mo amount is preferably more than 0.01%.But when Mo amount is more than 0.1%, TS makes ductility significantly reduce more than 900MPa, exceedingly high tensile.Therefore, it is less than 0.1% that Mo is measured, and is preferably less than 0.05%.
Below N:0.01%
When N amount is more than 0.01%, the ductility of steel reduces.Therefore, it is less than 0.01% that N is measured, and is preferably less than 0.005%.
Surplus is Fe and inevitable impurity.
2) microstructure
High-tensile steel of the present invention have by median size be 5 ~ 30 μm recrystallize austenite crystal or further in the microstructure of other organizational compositions of area occupation ratio less than 1%.In order to utilize the twinning-induced plasticity of austenite phase to realize high ductibility, microstructure is needed to be austenite one phase.In addition, in order to make or even Large strain district also stably shows twinning-induced plasticity, austenite crystal need for fully release internal strain can recrystal grain.And, when the median size of austenite crystal is less than 5 μm, is difficult in Large strain district generate mechanical twin, thus causes the generation of plasticity wild effect.Therefore, for high-tensile steel of the present invention, make the median size of recrystallize austenite crystal be more than 5 μm, preferably be more than 10 μm.On the other hand, when median size is more than 30 μm, be difficult to the TS obtaining expecting.Therefore, the median size of recrystallize austenite crystal is made to be less than 30 μm.
It should be noted that, for the high Mn austenitic steel plate that the present invention is such, sometimes according to the speed of cooling after the speed of cooling after hot rolling and annealing, generate its hetero-organization beyond cementite or the equal recrystallize austenite crystal of martensite.In order to stably obtain high tensile and excellent ductility, preferably suppress the generation of its hetero-organization as far as possible, as long as but its hetero-organization account for and organize overall area occupation ratio to be about less than 1%, then can not damage object of the present invention.That is, the microstructure that the recrystallize austenite crystal that it is 5 ~ 30 μm that high-tensile steel of the present invention has by median size is formed or further in the cementite of area occupation ratio less than 1% or martensite other tissues equal.High-tensile steel of the present invention has following microstructure, and the median size of recrystallize austenite crystal is 5 ~ 30 μm and this recrystallize austenite crystal accounts for steel plate organizes overall area occupation ratio to be more than 99%.
Wherein, for the median size of recrystallize austenite crystal, with the multiplying power of 1000 times to 5000 times, the SEM tissue of thickness of slab 1/4 position of the rolling direction parallel cutting surfaces of steel plate being carried out to multiple visual field observes, and with the identification of phases analyzed by EBSD, tried to achieve by image analysis.In addition, whether be less than 2 by the length-to-diameter ratio based on grain shape, determine whether recrystal grain, or further and confirm with the dependent variable presumption in the crystal grain analyzed by EBSD.
3) manufacturing condition
Below, the preferred manufacturing condition of steel plate of the present invention is shown.It should be noted that, the manufacture method of high-tensile steel of the present invention is not limited to following method.
The Heating temperature of steel billet: 1100 ~ 1300 DEG C
When the Heating temperature of steel billet is more than 1300 DEG C, hot workability reduces, and the energy required for heating increases.On the other hand, when Heating temperature is less than 1100 DEG C, the increase of load when causing hot rolling.Therefore, the Heating temperature of steel billet is made to be 1100 ~ 1300 DEG C, to be preferably 1150 ~ 1250 DEG C.It should be noted that, adding of steel billet is hankered, and can reheat being cooled to the steel billet after normal temperature, and steel billet that also can be high to the temperature in the process of cooling after casting auxiliarily heats or is incubated.
Finishing temperature during hot rolling: more than 800 DEG C
When finishing temperature during hot rolling is lower than 800 DEG C, recrystallize and grain growing can not be carried out fully, easily obtain the hot-rolled steel sheet of remaining non-recrystallization crystal grain, and cause the increase of rolling load when carrying out cold rolling afterwards.Therefore, finishing temperature during hot rolling is made to be more than 800 DEG C, to be preferably more than 850 DEG C.On the other hand, when finishing temperature is more than 1050 DEG C, crystal grain easily becomes excessively thick, and intensity and ductility reduce sometimes.Therefore, finishing temperature is preferably made to be less than 1050 DEG C.It should be noted that, in order to ensure finishing temperature, also can utilize the heating unit such as strip edge heater or strip well heater, the steel plate auxiliarily in heating rolling.
Speed of cooling after hot rolling: in the temperature range below 800 DEG C be more than 20 DEG C/sec
After hot rolling, when cooling with the speed of cooling being less than 20 DEG C/sec in the temperature range below 800 DEG C, in cooling, cementite is separated out, and ductility reduces.Therefore, after hot rolling, need to be cooled at least 600 DEG C with the speed of cooling of more than 20 DEG C/sec in the temperature range below 800 DEG C.It should be noted that, when the speed of cooling after hot rolling is more than 100 DEG C/sec, recrystallize does not complete sometimes, therefore, preferably makes the speed of cooling after hot rolling be less than 100 DEG C/sec.
It should be noted that, when finishing temperature is more than 800 DEG C, in order to promote recrystallize, also can until carry out 1 ~ 10 second naturally cooling (air cooling) in the temperature range of 800 DEG C.It should be noted that, in this situation, in the temperature range below 800 DEG C, be cooled at least 600 DEG C with the speed of cooling of more than 20 DEG C/sec.
Coiling temperature: less than 600 DEG C
When coiling temperature is more than 600 DEG C, generates cementite in the Slow cooling process after batching, cause the reduction of ductility.Therefore, make coiling temperature be less than 600 DEG C, be preferably less than 550 DEG C.
Steel plate after the hot rolling of such manufacture, can directly as high-tensile steel of the present invention, but also can by after the steel plate descaling after hot rolling or by after the steel plate descaling after hot rolling and cold rolling after, anneal under following annealing conditions.It should be noted that, descaling can be undertaken by ordinary methods such as pickling.
Annealing conditions: annealing temperature: 750 ~ 1050 DEG C, from annealing temperature until the speed of cooling of the temperature range of at least 450 DEG C: more than 10 DEG C/sec
In order to promote the grain growing of the steel plate after hot rolling, can anneal under the annealing temperature of 750 ~ 1050 DEG C.More preferably anneal under the annealing temperature of 800 ~ 1000 DEG C.
In addition, in order to obtain expect thickness of slab, when to after hot rolling steel plate implement cold rolling after steel plate anneal, need to anneal under the annealing temperature of 750 ~ 1050 DEG C.This is to make the organization formation of steel plate be the microstructure that the recrystallize austenite crystal being 5 ~ 30 μm by median size is formed.When annealing temperature is lower than 750 DEG C, recrystallize does not complete, and can not get sufficient ductility.On the other hand, when annealing temperature is more than 1050 DEG C, crystal grain becomes excessively thick, and intensity and ductility reduce sometimes.More preferably anneal under the annealing temperature of 800 ~ 1000 DEG C.It should be noted that, as long as cold rolling rolling rate can obtain the rolling rate of the thickness of slab expected, be not particularly limited, but from the view point of production efficiency, be preferably about 50% ~ about 70%.
No matter with or without cold rolling, from annealing temperature until when the speed of cooling of at least 450 DEG C is less than 10 DEG C/sec, generate cementite, ductility reduces.Therefore, from annealing temperature until the temperature range of at least 450 DEG C needs to cool with the speed of cooling of more than 10 DEG C/sec.
In order to melting steel of the present invention, can use in converter, electric furnace any one.The steel of such melting, obtains steel billet by ingot casting-split rolling method or continuous casting.As required, the surfacing etc. of various pre-treatment, secondary refining or steel billet is preferably implemented.In addition, about annealing, from the view point of productivity, implement preferably by continuous annealing apparatus.Even if implement various plating to the steel plate after the steel plate after hot rolling or annealing also can not damage effect of the present invention.The temper rolling being used for shape correction or reconciliation statement surface roughness can also be implemented to the steel plate after the steel plate after hot rolling, annealing or the steel plate after plating.In addition, application, the various surface treatment such as coated can also be implemented to steel plate of the present invention.
Embodiment
Hot rolling is carried out under the steel billet of steel A ~ K that the one-tenth shown in his-and-hers watches 1 the is grouped into hot-rolled condition shown in table 2, obtain the hot-rolled steel sheet of thickness of slab 3mm, by pickling except after descaling, anneal under the annealing conditions of a part of steel plate further shown in table 2, or carry out cold rolling after annealing under cold rolling rate shown in table 2 and annealing conditions, after making hot rolling, hot rolling+annealing, the cold rolling+steel plate 1 ~ 20 of annealing.
For the steel plate made, investigate microstructure by aforesaid method, obtain the median size of formation, recrystallize austenite crystal mutually.It should be noted that, in table 3, about forming mutually, tissue beyond recrystallize austenite crystal is observed more than 1% in area occupation ratio, represent the kind of its hetero-organization, when its hetero-organization is counted below 1% with area occupation ratio, represent recrystallize austenite.In addition, choose the 13B test film of regulation in JIS Z 2201 along rolling direction, according to the method for regulation in JIS Z 2241, implement tension test, obtain TS, El, l-El, TS × El.It should be noted that, when TS × El is more than 60GPa%, be judged to be the high-tensile steel that ductility is excellent.
Show the result in table 3.The microstructure that the recrystallize austenite crystal that it is more than 5 μm that the steel plate of example of the present invention all has by median size is formed, TS is 700 ~ 900MPa, l-El is more than 5%, TS × El is more than 60GPa%, the high-tensile steel that the known ductility being burst when can avoid stamping is ruptured is excellent.In addition, when meeting above-mentioned (1) formula, known TS × El is excellent especially.
Table 1
(quality %)
Table 2
* less than speed of cooling 1:800 DEG C until the speed of cooling of coiling temperature
* speed of cooling 2: from annealing temperature until the speed of cooling of 450 DEG C
Table 3
※ Y: austenite, M: martensite
Claims (5)
1. the high-tensile steel that a ductility is excellent, it is characterized in that, there is following one-tenth be grouped into, in mass %, containing C:0.5 ~ 1.5%, below Si:0.1%, Mn:10 ~ 25%, below P:0.1%, below S:0.05%, below Al:0.1%, Ni:3.0 ~ 8.0%, below Mo:0.1%, below N:0.01%, surplus is made up of Fe and inevitable impurity, and there is following microstructure, be the recrystallize austenite crystal of 5 ~ 30 μm by median size or further count less than 1% with area occupation ratio, other organizational compositions containing cementite,
The tensile strength of described high-tensile steel is 700 ~ 900MPa, TS × El be more than 60GPa%, l-El is more than 5%.
2. high-tensile steel as claimed in claim 1, is characterized in that, in mass % containing Ni:4.0 ~ 8.0%, the median size of described recrystallize austenite crystal is 10 ~ 30 μm, and l-El is more than 7.6%.
3. the manufacture method of the high-tensile steel that a ductility is excellent, it is characterized in that, the steel billet that the one-tenth had described in claim 1 or 2 is grouped into is reheated to the Heating temperature of 1100 ~ 1300 DEG C, hot rolling is carried out with the finishing temperature of more than 800 DEG C, temperature range below 800 DEG C is cooled at least 600 DEG C with the speed of cooling of more than 20 DEG C/sec, batches with the coiling temperature of less than 600 DEG C.
4. the manufacture method of the high-tensile steel that ductility as claimed in claim 3 is excellent, it is characterized in that, after batching, carry out descaling further, anneal with the annealing temperature of 750 ~ 1050 DEG C, from annealing temperature until the temperature range of at least 450 DEG C cools with the speed of cooling of more than 10 DEG C/sec.
5. the manufacture method of the high-tensile steel that ductility as claimed in claim 3 is excellent, it is characterized in that, after batching, carry out descaling, cold rolling further, then, anneal with the annealing temperature of 750 ~ 1050 DEG C, from annealing temperature until the temperature range of at least 450 DEG C cools with the speed of cooling of more than 10 DEG C/sec.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2010077305A JP5003785B2 (en) | 2010-03-30 | 2010-03-30 | High tensile steel plate with excellent ductility and method for producing the same |
| JP2010-077305 | 2010-03-30 | ||
| PCT/JP2011/055007 WO2011122237A1 (en) | 2010-03-30 | 2011-02-25 | Steel sheet with high tensile strength and superior ductility and method for producing same |
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| CN102822371A CN102822371A (en) | 2012-12-12 |
| CN102822371B true CN102822371B (en) | 2015-05-20 |
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| EP (1) | EP2554699B1 (en) |
| JP (1) | JP5003785B2 (en) |
| KR (1) | KR101287331B1 (en) |
| CN (1) | CN102822371B (en) |
| WO (1) | WO2011122237A1 (en) |
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| US20140261918A1 (en) * | 2013-03-15 | 2014-09-18 | Exxonmobil Research And Engineering Company | Enhanced wear resistant steel and methods of making the same |
| KR101665807B1 (en) | 2014-12-23 | 2016-10-13 | 주식회사 포스코 | High manganese steel sheet having excellent hot dip aluminium coatability, and method for manufacturing the same |
| KR101665801B1 (en) | 2014-12-23 | 2016-10-13 | 주식회사 포스코 | High manganese steel sheet having excellent hot dip aluminium coatability, and method for manufacturing the same |
| KR20160078840A (en) | 2014-12-24 | 2016-07-05 | 주식회사 포스코 | High manganese steel sheet having superior yield strength and fromability, and method for manufacturing the same |
| CN104711494B (en) * | 2015-04-14 | 2017-11-28 | 钢铁研究总院 | Low-density high-ductility NiAl strengthens unimach and preparation method |
| JP6455333B2 (en) * | 2015-06-23 | 2019-01-23 | 新日鐵住金株式会社 | High Mn steel for high-pressure hydrogen gas and pipes, containers, valves and joints made of the steel |
| US20190010590A1 (en) * | 2015-12-22 | 2019-01-10 | Posco | Austenitic steel material having excellent hydrogen-embrittlement resistance |
| KR102065287B1 (en) | 2015-12-24 | 2020-01-10 | 주식회사 포스코 | Austenitic hot-dip aluminum coated steel sheet with excellent plating property and weldability, and a manufacturing method thereof |
| KR101747034B1 (en) | 2016-04-28 | 2017-06-14 | 주식회사 포스코 | Ultra high strength and high ductility steel sheet having excellent yield ratio, and method for manufacturing the same |
| US20170349983A1 (en) * | 2016-06-06 | 2017-12-07 | Exxonmobil Research And Engineering Company | High strength cryogenic high manganese steels and methods of making the same |
| TWI630277B (en) * | 2016-12-19 | 2018-07-21 | 杰富意鋼鐵股份有限公司 | High manganese steel plate and manufacturing method thereof |
| KR101940874B1 (en) | 2016-12-22 | 2019-01-21 | 주식회사 포스코 | High manganese steel with superior low temperature toughness and yield strength and method for manufacturing the same |
| JP2018162507A (en) * | 2017-03-27 | 2018-10-18 | 新日鐵住金株式会社 | High-strength oil well steel and oil well pipe |
| MY194444A (en) * | 2017-09-01 | 2022-11-30 | Jfe Steel Corp | High-mn steel and production method therefor |
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| US20210164067A1 (en) * | 2017-12-07 | 2021-06-03 | Jfe Steel Corporation | High-mn steel and method for manufacturing same |
| KR101999032B1 (en) | 2017-12-26 | 2019-09-27 | 주식회사 포스코 | High manganese coated steel welded structure with superior spot weldability and method for manufacturing same |
| KR102065230B1 (en) | 2017-12-26 | 2020-01-10 | 주식회사 포스코 | Zinc coated high manganese steel sheet with superior spot weldability and method for manufacturing same |
| JP6590120B1 (en) * | 2018-02-07 | 2019-10-16 | Ｊｆｅスチール株式会社 | High Mn steel and manufacturing method thereof |
| CN112513307A (en) * | 2018-08-03 | 2021-03-16 | 杰富意钢铁株式会社 | High Mn steel and method for producing same |
| JP6947330B2 (en) * | 2019-08-21 | 2021-10-13 | Ｊｆｅスチール株式会社 | Steel and its manufacturing method |
| KR102462130B1 (en) * | 2020-10-26 | 2022-11-03 | 현대제철 주식회사 | Method of manufacturing ultra high strength hot rolled steel sheet having softening heat treatment and apparatus of manufacturing hot rolled steel sheet |
| CN113278894A (en) * | 2021-05-20 | 2021-08-20 | 成都先进金属材料产业技术研究院股份有限公司 | Fe-Mn-Al-S series low-density free-cutting steel and preparation method thereof |
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2010
- 2010-03-30 JP JP2010077305A patent/JP5003785B2/en active Active
-
2011
- 2011-02-25 WO PCT/JP2011/055007 patent/WO2011122237A1/en active Application Filing
- 2011-02-25 EP EP11762477.5A patent/EP2554699B1/en not_active Not-in-force
- 2011-02-25 CN CN201180016733.9A patent/CN102822371B/en not_active Expired - Fee Related
- 2011-02-25 KR KR1020127021879A patent/KR101287331B1/en active IP Right Grant
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN1079513A (en) * | 1991-12-30 | 1993-12-15 | 浦项综合制铁株式会社 | Hadfield Steel and manufacturing process thereof with superior formability, intensity and weldability |
| CN1846002A (en) * | 2003-07-22 | 2006-10-11 | 于西纳公司 | Method of producing austenitic iron/carbon/manganese steel sheets having a high strength and excellent toughness and being suitable for cold forming, and sheets thus produced |
Also Published As
| Publication number | Publication date |
|---|---|
| EP2554699A4 (en) | 2015-07-08 |
| EP2554699A1 (en) | 2013-02-06 |
| WO2011122237A1 (en) | 2011-10-06 |
| JP2011208226A (en) | 2011-10-20 |
| CN102822371A (en) | 2012-12-12 |
| EP2554699B1 (en) | 2016-08-10 |
| JP5003785B2 (en) | 2012-08-15 |
| KR20120113789A (en) | 2012-10-15 |
| KR101287331B1 (en) | 2013-07-23 |
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