CN104641008A - Cold-rolled flat steel product and method for the production thereof - Google Patents
Cold-rolled flat steel product and method for the production thereof Download PDFInfo
- Publication number
- CN104641008A CN104641008A CN201380048837.7A CN201380048837A CN104641008A CN 104641008 A CN104641008 A CN 104641008A CN 201380048837 A CN201380048837 A CN 201380048837A CN 104641008 A CN104641008 A CN 104641008A
- Authority
- CN
- China
- Prior art keywords
- cold
- weight
- flat product
- content
- temperature
- 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.)
- Granted
Links
Classifications
-
- 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
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/58—Ferrous alloys, e.g. steel alloys containing chromium with nickel with more than 1.5% by weight of manganese
-
- 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
- C21D6/002—Heat treatment of ferrous alloys containing Cr
-
- 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
- C21D6/004—Heat treatment of ferrous alloys containing Cr and Ni
-
- 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
- C21D6/005—Heat treatment of ferrous alloys containing Mn
-
- 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
- C21D6/008—Heat treatment of ferrous alloys containing Si
-
- 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
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
- C21D8/0236—Cold rolling
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- 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
-
- 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
- C21D8/0263—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment following hot rolling
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- 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
-
- 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
- C21D9/52—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for wires; for strips ; for rods of unlimited length
-
- 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
-
- 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
-
- 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
-
- 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
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/20—Ferrous alloys, e.g. steel alloys containing chromium with copper
-
- 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
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/24—Ferrous alloys, e.g. steel alloys containing chromium with vanadium
-
- 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
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/28—Ferrous alloys, e.g. steel alloys containing chromium with titanium or zirconium
-
- 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
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/34—Ferrous alloys, e.g. steel alloys containing chromium with more than 1.5% by weight of 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
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/38—Ferrous alloys, e.g. steel alloys containing chromium with more than 1.5% by weight of manganese
-
- 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
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/42—Ferrous alloys, e.g. steel alloys containing chromium with nickel with copper
-
- 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
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
-
- 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
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/46—Ferrous alloys, e.g. steel alloys containing chromium with nickel with vanadium
-
- 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
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/48—Ferrous alloys, e.g. steel alloys containing chromium with nickel with niobium or tantalum
-
- 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
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/50—Ferrous alloys, e.g. steel alloys containing chromium with nickel with titanium or zirconium
-
- 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
- C21D2211/002—Bainite
-
- 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
Abstract
The invention relates to a cold-rolled flat steel product with the characteristics Rm >= 1400 MPa and A80 >= 5%, and to a process for producing such a flat steel product. The flat steel product according to the invention contains, in addition to Fe and unavoidable impurities (in percent by weight): 0.10-0.60% of C, 0.4-2.5% of Si, <= 3.0% of Al, 0.4-3.0% of Mn, <= 1.0% of Ni, <= 2.0% of Cu, <= 0.4% of Mo, <= 2% of Cr, <= 1.5% of Co, <= 0.2% of Ti, <= 0.2% of Nb, <= 0.5% of V. The structure has (in percent by volume) >= 20% of bainite, 10-35% of residual austenite, the remainder being martensite. In oder to produce the flat steel product, a slab, a thin slab or a cast strip having said composition is provided. The pre-product is hot-rolled with a final hot-rolling temperature of >= 830 DEG C to a hot strip, the hot strip is then coiled at a coiling temperature of <= 560 DEG C. The hot strip is cold-rolled at a cold-rolling rate of >= 30% to form a cold strip, and the cold strip is thermally treated by heating it first to an annealing temperature of >= 800 DEG C, then cooling it at a cooling rate of >= 8 DEG C/s to a holding temperature of 470 DEG C until above the initial martensite temperature MS and is then maintained at the holding temperature until at least 20 percent by volume of bainite are present in the structure of the cold strip.
Description
Technical field
The present invention relates to a kind of flat cold-rolled bar product with the ductility A80 of the tensile strength Rm and at least 5% of at least 1400 MPas.Such product is due to very high intensity and have good ductility and well-known, and is especially suitable for the component of maker multiple unit train body.
The present invention relates to a kind of method for the manufacture of flat product according to the present invention equally.
Background technology
Term " flat product " this be understood to imply the steel plate or steel band that are manufactured by rolling technology and sheet band with from the analogue be wherein separated.
Wherein, alloy content is only stated with " % " at this, and this means all the time " weight percent ", unless be specifically recited in addition.
EP1466024B1 (DE60315129T2) discloses a kind of method of producing flat product, and it is intended to produce and has significantly higher than the tensile strength of 1000 MPas.In order to reach this object, the molten steel of fusing is manufactured, wherein contain with the carbon of the 0.0005-1% of weight percent, the copper of 0.5-10%, up to the manganese of 2%, up to the silicon of 5%, up to the titanium of 0.5%, up to 0.5% niobium, up to the nickel of 5%, the aluminium up to 2% and the iron as remainder and the inevitable impurity due to production reason.This molten steel melt is cast to form band shape, maximum 10 millimeters and under being sprayed be cooled to rapidly the temperature of 1000 DEG C at the most by water or water-air mixture of its thickness.Then, this cast steel strip carries out hot rolling under conventional warm-down rate.Hot rolling completes under end temp, and copper all at such a temperature is still in sosoloid in ferrite and/or austenite matrix.Then, this band stands quick refrigerating work procedure, thus is remained on by copper in the supersaturated solid solution of ferrite and/or austenite solution.After cooling forms steel ring, cold steel band can be formed by hot steel band rolling and obtain the cold rolling degree reaching 40-80% thus.This cold-rolled steel strip carries out recrystallization annealing subsequently, and it is brought into the annealing temperature that is in 840 DEG C of regions as quickly as possible and keeps at said temperatures, so that Copper in Iron and Steel is added in solution by maximum possible ratio during this period.Be be cooled fast to reach 400-700 DEG C of temperature after this, again form the precipitate of Cu at this temperature.By this way, the object of precipitation-hardening is the ideal tensile strength realizing steel.Meanwhile, the content of copper is to increase the erosion resistance of iron and steel and anti-fragility by forming anti-oxidant nitride layer.
The other method of producing the cold-rolled steel strip of very high strength is disclosed by US7591977B2.According to the method, carbon containing (by weight percentage) 0.1-0.25%, the hot rolled strip of the silicon of 1.0-2.0% and the manganese of 1.5-3.0% forms cold-rolled steel strip with the degree that 30-70% is cold rolling, and then this cold steel band completes thermal treatment in continuous print path.In this thermal treatment, this cold-rolled steel strip is heated to the first annealing temperature on Ar3 temperature in the first annealing steps, so that the carbide be present in described cold-rolled steel strip is brought in solution.Then be cooling, from the first annealing temperature and with the speed of cooling of at least 10 DEG C/sec to the second annealing temperature.This temperature is selected such that bainite form to be usually located in the scope of 300-450 DEG C in cold-rolled steel strip.Implement to be performed with this second annealing steps forming bainite until the microtexture of this cold-rolled steel strip is made up of the bainite of at least 60% degree and the retained austenite of at least 5% degree and remaining polygonal ferrite.At this, the microtexture that the object of the invention is maximum possible scope is bainite and the composition of other microtexture exists a little vestige at the most.Thus provided cold-rolled steel strip realizes the tensile strength up to 1180 MPas and possesses the ductility of at least 9%, and if if required, the metal level of anticorrosive protection can be adopted to apply.
Summary of the invention
For the background technology of above-mentioned described prior art, the object of this invention is to provide a kind of flat cold-rolled bar product, it can carry out producing with simple and the reliable mode of operation and have the optimum combination characteristic of intensity and the good deformability improved further.In addition, the object of this invention is to provide a kind of method of producing such flat cold-rolled bar product.
For flat cold-rolled bar product, achieved by the flat product shown in claim 1 according to this object of the present invention.
As for the method, be achieved according to object mentioned above the present invention, the algorithm namely at least shown in claim 12 is implemented produces according to flat cold-rolled bar product of the present invention.
Favourable configuration of the present invention is described in the dependent claims and will be explained in detail below as upperseat concept of the present invention.
Flat cold-rolled bar product according to the present invention is significantly distinguished and is that, outside deironing and inevitable impurity, it comprises (weight percent):
C：0.10-0.60％，
Si：0.4-2.5％，
Al: up to 3.0%,
Mn：0.4-3.0％，
Ni: up to 1.0%,
Cu: up to 2.0%,
Mo: up to 0.4%,
Cr: up to 2%,
Co: up to 1.5%,
Ti: up to 0.2%,
Nb: up to 0.2%,
V: up to 0.5%.
At this, under Cold Rolled Strip, according to the microtexture of flat product of the present invention by the bainite of at least 20 volume %, 10-35 volume % retained austenite and martensite as remainder, self-evidently technically inevitably the vestige of the composition of other microtexture can be present in the microtexture of this flat product.According to the present invention, flat cold-rolled bar product provided in this way reaches the ductility A80 of the tensile strength Rm and at least 5% of at least 1400 MPas.C content in retained austenite is generally greater than 1.0% of weight.
According to provided by the present invention or comprise following algorithm according to the method for the production of flat product that the present invention conceives:
-providing primary products in the mode of slab, thin slab or casted steel belt, it comprises (with weight percent) C:0.10-0.60%, Si:0.4-2.5% except iron and inevitable impurity, Al: up to 3.0%, Mn:0.4-3.0%, Ni: up to 1.0%, Cu: up to 2.0%, Mo: up to 0.4%, Cr: up to 2%, Co: up to 1.5%, Ti: up to 0.2%, Nb: up to 0.2%, V: up to 0.5%;
Primary products described in-hot rolling to form hot rolled strip in one or more roll path, and wherein, the hot rolled strip obtained has the hot rolling end temp of at least 830 DEG C when it leaves last roll path;
The hot rolled strip that the gained that reels under-coiling temperature between hot rolling end temp and 560 DEG C arrives;
-this hot rolled strip cold rolling has at least 30% cold rolling cold-rolled steel strip to be formed;
The cold-rolled steel strip that-thermal treatment obtains, wherein in described heat treated process, this cold-rolled steel strip
-heated the annealing temperature reaching at least 800 DEG C,
-under this annealing temperature, optionally keep the anneal duration of 50-150 second,
-be cooled to maintenance temperature with the rate of cooling of at least 8 DEG C/s from this annealing temperature, this maintenance temperature is positioned at and keeps temperature range, this maintenance temperature range has 470 DEG C of upper limits and has the lower limit higher than martensite start temperature MS, from this martensite start temperature, martensite form in the microtexture of cold-rolled steel strip, and
-at this maintenance temperature, be kept for some time of being enough to form at least 20 volume % bainites in the microtexture of cold-rolled steel strip.
Steel band according to the present invention has three-phase microtexture, and wherein prevailing composition is martensite and it also forms by the bainite remained with as the austenite of remainder.Be at least 50 volume % in the ratio of this preferably bainite, particularly at least 60 volume %, and the ratio of this retained austenite is in 10-25 volume %, and the remainder of the microtexture be made up of martensite in each case.Preferred martensitic ratio is at least 10 volume %.The microtexture with this kind of component produces the best of breed with the Rm*A80 of required tensile strength.
Except main component " bainite ", " retained austenite " and " martensite ", occur that the content of the component of other microtexture is possible, but the ratio of these components is too low to such an extent as to do not affect the performance of cold-rolled steel strip according to the present invention.This retained austenite is mainly present in according in cold-rolled steel strip of the present invention with the form of the film with the globular island of the block retained austenite being less than 5 micron granularities, make described retained austenite have high stability in an initial condition and associated therewith be low change undesirable martensitic trend into.When the higher degree be out of shape, martensite is formed by this retained austenite (TRIP effect), and which increases the ductility of fracture.
Cold-rolled steel strip produced according to the invention realizes the tensile strength Rm more than 1400 MPas usually, has the ductility A80 more than 5% of similar routine.Therefore, according to the quality Rm*A80 of flat product of the present invention usually more than 7000MPa*%, the quality Rm*A80 with at least 13500MPa*% is typically achieved.This cold-rolled steel strip according to the present invention is the optimum combination with very high intensity and enough deformabilities.
Martensitic beginning temperature, namely from this temperature, martensite form is in the steel processed according to the present invention, and the operation described in article that can be published in the 178-180 page of the metal science 15 (Metal Science 15) that 1981 publish based on author H.Bhadeshia, that be entitled as " Thermodynamic Extrapolation and Martensite-Start-Temperature of Substitutionally Alloyed Steels " calculates.
In steel according to the present invention, carbon is delayed the transformation to ferrite/pearlite (pearlite), reduces martensitic beginning temperature MS and contributes to increasing hardness.In order to the effect utilizing these positive, C content according to flat product of the present invention can be set at least 0.25 % by weight, particularly at least 0.27 % by weight or at least 0.28 % by weight, effect acquired by relatively high carbon content is possible by being reliably used especially, when C content is in the scope being less than 0.25-0.5 % by weight, particularly 0.27-0.4 % by weight or 0.28-0.4 % by weight.
The effect that copper is gained in strength also can be used in according in flat cold-rolled bar product of the present invention.In this respect, minimum 0.15 % by weight particularly at least 0.2 % by weight Cu content can appear at according in flat product of the present invention.Copper especially effectively acts on for intensity contribution, if its with at least 0.55 % by weight content be present in according in flat product of the present invention; It is possible for based on the fact, the content of Cu being limited in maximum 1.5 % by weight and suppressing Cu to there is the counter productive produced.
In steel according to the present invention, at least 0.4 % by weight and at the most 3 % by weight, particularly up to the Mn of 2.5 % by weight content, promote the formation of bainite, the copper optionally existed in addition, the content of chromium and nickel contributes to the formation of bainite equally.Depend on other composition corresponding of the steel processed according to the present invention, also can limit Mn content valuably to maximum less than 2 % by weight or increase the minimum content of Mn to 1.5 % by weight at this.
Optionally adding of Cr also can reduce martensitic beginning temperature and suppress bainite transformation to become the trend of perlite or cementite.In addition, as predefined according to the present invention institute, have the optional effect that Cr in flat cold-rolled bar product according to the present invention exists can raise when Cr content is limited to 1.5 % by weight, during for content up to 2 % by weight upper limits at the most, chromium promotes ferritic transformation.The positive impact of Cr can be used especially effectively, if the Cr of at least 0.3 % by weight is present in according in flat product of the present invention.
The interpolation of Ti, V or Nb is optional equally, and it can be supported the formation of fine granularity microtexture and promote the transformation of bainite.In addition, these microalloy elements are formed with by precipitate the increase helping hardness.The positively effect of Ti, V and Nb in a particularly efficient manner, can be used in according in flat cold-rolled bar product of the present invention, when the content of these elements is in the scope of 0.002-0.15 % by weight, is particularly no more than 0.1 % by weight.
Silicon is present according to causing sizable solid solution to solidify in flat product of the present invention with the content of 0.4-2.5 % by weight.In order to utilize this effect in a particularly reliable manner, the content of Si can be set at least 1.0 % by weight.Similarly, in order to avoid negative impact, the content of restriction Si is maximum 2 % by weight is useful.
In the steel processed according to the present invention, aluminium can the content of Some substitute Si.Meanwhile, similar with Si, aluminium has deoxygenation in steel manufacture process.In order to this object, can provide minimum is the Al of 0.01 % by weight content.Higher aluminium content is proved to be favourable, such as, when the interpolation of Al is to the hardness of iron and steel or tensile strength are set as low value is beneficial to the deformability improved.
Another function of Si and Al comprises and suppresses the formation of carbide in bainite and therefore stablize retained austenite by dissolving C until low temperature.
Therefore the simultaneous positive impact of Al and Si can be utilized, when the content of Si and Al be in according in the predefined limited field of the present invention to meet following condition: 0.8%Si+0.8%Al > 1.2 % by weight is (wherein, %Si characterizes in the content of the Si of % by weight, and Al% characterizes in the content of the Al of % by weight).
Formation according to predefined microtexture of the present invention can be guaranteed, the content of manganese, chromium, nickel, copper and carbon in the iron and steel particularly namely processed according to the present invention by this fact and meet following condition according to the content of corresponding in band steel of the present invention manganese, chromium, nickel, copper and carbon:
1 < 0.5%Mn+0.167%Cr+0.125%Ni+0.125% copper+1.334%C < 2
Wherein, %Mn characterizes in the content of the corresponding Mn of % by weight, %Cr characterizes in the content of the corresponding Cr of % by weight, and %Ni characterizes in the content of the corresponding Ni of % by weight, and %Cu characterizes and characterizes in the content of the corresponding C of % by weight in the content of the corresponding Cu of % by weight and %C.
In order to produce according to flat product of the present invention, first be brought to by having the original or primary products of casting according to the steel of constituent of the present invention or remain on certain temperature, this temperature be enough to terminate hot rolling technology, this hot rolling technology from be positioned at 830-1000 DEG C of scope hot rolling end temp place this temperature perform processing.After it leaves the last rolling support being used to hot rolling, described hot rolled strip is cooled in the roller tables adjacent with roller mill.And then this roller tables, this hot rolled strip enters in wind2, is wound wherein to form a volume circle.
Coiling temperature must be at least 560 DEG C, and hot rolled strip microtexture that is softer, that be made up of ferrite and pearlite is formed.Preferable temperature curve for this purpose creates, if hot rolling end temp is in the scope of 850-950 DEG C, particularly in the scope of 880-950 DEG C.For this purpose, under usual primary products are heated to the temperature of the scope being positioned at 1100-1300 DEG C or before remaining on hot rolling at this temperature.The microtexture of the hot rolled strip so obtained forms primarily of ferrite and pearlite.Occur that the risk of grain boundary oxidation can rely on this fact to be minimized, namely this coiling temperature is restricted to the highest 750 DEG C.
After winding, this hot rolled strip is carried out cold rolling, and self-evidently, hot rolled strip can be removed oxide layer routinely by chemistry or mechanical means before cold rolling.
Cold rollingly be implemented at least 30% particularly at least 45% cold rolling degree, so that accelerate recrystallisation and transformation in annealing process subsequently.Usually better surface quality also can obtain by observing cold rolling relatively high degree.It is particularly advantageous that the cold rolling degree of at least 50% has been proved to be for this object.
After cold rolling, complete the annealing cycle according to the cold-rolled steel strip that the present invention obtains in continuous path, during this period, it is heated at least 800 DEG C at the first annealing stage, preferably the temperature of at least 830 DEG C.This first annealing stage continues for some time at least like this, thus this cold-rolled steel strip is by complete austenitizing.Usually need 50-150 second for this reason.
First annealing stage phase, this product with speed of cooling at least 8 DEG C/sec particularly 10 DEG C/sec quenched.The target temperature for this reason quenched is the maintenance temperature of maximum 470 DEG C and it is higher than martensite start temperature MS, temperature from this, martensite form cold-rolled steel strip microtexture in.In practice, 300-420 DEG C particularly the scope of 330-420 DEG C can be used to show this scope residing for maintenance temperature.
Process from respective maintenance temperature, cold-rolled steel strip is maintained at the second annealing stage and keeps in temperature range, precisely until the microtexture of the cold-rolled steel strip of at least 20 volume % is converted into bainite.This remain on this can be performed as during cooling isothermal at the maintenance temperature that arrives to keep or keeping the slow reduction temperature in temperature range.
Flat product produced according to the invention can metal coated protective layer in a usual manner.Such as this can be realized by hot dip coating.If needed annealing before metallic coating applies, can carry out in the process of this annealing according to thermal treatment provided by the present invention.
Embodiment
The present invention is described in more details on the basis of exemplary embodiment subsequently.
Five pieces of steel S1-S5 are melted, and its component is labeled in Table 1.
The steel melt of respective components is carried out building to form blank in a conventional manner, from this blank, isolate thick plate.Then this thick plate is heated to similar usual manner and reheats temperature.
By the slab that heats with similar conventional hot rolling station group by hot rolling to form the hot rolled strip with 2mm thickness.
In each case, this hot rolling end temp is in the scope of 830-900 DEG C.This hot rolled strip is cooled to the coiling temperature that is positioned on 560 DEG C and is wound subsequently to form volume circle from this temperature.
This hot rolled strip so obtained is removed top layer and is had the cold-rolled steel strip of 50% cold rolling degree by cold rolling to be formed after removing top layer after winding.
Relatively a large amount of sample of these cold-rolled steel strips is then through heat-treated, and in this thermal treatment, it is heated to the first annealing temperature being positioned at 830-850 DEG C of scope in the first annealing steps with the heating rate of at least 1.9 DEG C/sec.This cold-rolled steel strip is kept the time of 120 seconds in this temperature, until they add heat penetration completely.
What carry out subsequently is quenching, and during this period, cold-rolled steel strip is quenched into the maintenance temperature T2 be within the scope of 350-420 DEG C with the rate of cooling of at least 8 DEG C/sec.Specifically, test first in, this maintenance temperature T2 is 300 DEG C, 310 DEG C, 330 DEG C, 340 DEG C, 375 DEG C, 390 DEG C and 410 DEG C.The sample of this cold-rolled steel strip has been kept anneal duration t2 under respective maintenance temperature T2.
In FIG, the tensile strength Rm realized is drawn for the figure of respective annealing temperature T2.Can find out, the cold-rolled steel strip sample produced by steel S5 only all reaches the minimum tensile strength required for 1400 MPas under specific annealing conditions, but the tensile strength of the cold-rolled steel strip sample produced by other steel is all the time reliably higher than minimum limit 1400 MPa.The carbon content that steel S5 is relatively low is in the lower limit according to the content range preset of the present invention, is confirmed as the very crux.
In fig. 2, the figure of the annealing time t2 of drawn second annealing stage of tensile strength of the cold-rolled steel strip sample produced by steel S4.Can find out, no matter respective annealing time t2, the cold-rolled steel strip sample be kept at the maintenance temperature at the maintenance temperature of 310 DEG C, 330 DEG C and 350 DEG C namely in the maintenance temperature range of 310-350 DEG C reaches required 1400MPa tensile strength.
In figure 3, the tensile strength of the cold-rolled steel strip sample produced by steel S5 is by the diagram of anneal duration t2 be plotted as similarly for the second annealing stage.Can see, the cold-rolled steel strip sample be kept at the maintenance temperature at the maintenance temperature of 350 DEG C and 390 DEG C namely within the scope of 350-390 DEG C reaches required 1400MPa tensile strength, if anneal duration t2 is less than 145 seconds.
In the diagram, the ductility A80 of the cold-rolled steel strip sample produced by steel S4 is plotted as the diagram of the anneal duration t2 for the second annealing stage.No matter corresponding anneal duration t2, namely keep temperature range at 310-350 DEG C at the maintenance temperature of 310 DEG C, 330 DEG C and 350 DEG C under, the cold-rolled steel strip sample be kept reaches required minimum ductility A80.
In Figure 5, the ductility A80 of the cold-rolled steel strip sample produced by steel S5 is plotted as the diagram of the annealing time t2 for the second annealing stage.Also can find out at this, no matter each keeps temperature T2 and each anneal duration t2 thereof, this cold-rolled steel strip sample reaches the required ductility A80 of at least 5%.Therefore, if short anneal duration and suitably low maintenance temperature T 2 are acted in accordance with it, there is high tensile strength Rm and be combined with can being produced by steel S5 according to flat cold-rolled bar product of the present invention of enough ductility A80, although its relatively low C content.
Fig. 6 shows the enlarged view of the cross section according to cold-rolled steel strip of the present invention in part.In the figure, the block RA-b of such as retained austenite is labeled and this is emphasized by the mode of drawing a circle, and at this some place, film like retained austenite RA-f presents with the layered mode of stratiform.
Claims (15)
1. a flat cold-rolled bar product, has the ductility A80 of the tensile strength Rm and at least 5% of at least 1400MPa, and outside deironing and inevitable impurity, containing in % by weight:
Carbon: 0.10-0.60%,
Silicon: 0.4-2.5%,
Aluminium: up to 3.0%,
Manganese: 0.4-3.0%,
Nickel: up to 1.0%,
Copper: up to 2.0%,
Molybdenum: up to 0.4%,
Chromium: up to 2%,
Cobalt: up to 1.5%,
Titanium: up to 0.2%,
Niobium: up to 0.2%,
Vanadium: up to 0.5%,
Wherein, this flat product microtexture by reach at least 20 volume % bainite, reach 10 – 35 volume % retained austenite and form as the martensite of remainder.
2. flat product according to claim 1, is characterized in that, the carbon content of this flat product is at least 0.25 % by weight.
3. the flat product according to aforementioned any one claim, is characterized in that, the carbon content of this flat product is at least 0.27 % by weight.
4. the flat product according to aforementioned any one claim, is characterized in that, the silicone content of this flat product is at least 1.0 % by weight.
5. the flat product according to aforementioned any one claim, is characterized in that, the aluminium content of this flat product is at least 0.01 % by weight.
6. the flat product according to aforementioned any one claim, is characterized in that, the copper content of this flat product is at least 0.2 % by weight.
7. flat product according to claim 5, is characterized in that, the copper content of this flat product is at least 0.55 % by weight.
8. the flat product according to aforementioned any one claim, is characterized in that: the chromium content of this flat product is at least 0.3 % by weight.
9. the flat product according to aforementioned any one claim, is characterized in that, the content of the manganese of this flat product, chromium, nickel, copper and carbon meets following condition:
1<0.5% manganese+0.167% chromium+0.125% nickel+0.125% copper+1.334% carbon <2,
Wherein, % manganese: in the content of the corresponding manganese of % by weight,
% chromium: in the content of the corresponding chromium of % by weight,
% nickel: in the content of the corresponding nickel of % by weight,
% copper: in the content of the corresponding copper of % by weight,
% carbon: in the content of the corresponding carbon of % by weight.
10. the flat product according to aforementioned any one claim, is characterized in that, the microtexture of this flat product comprises the bainite of at least 50 volume %.
11. flat products according to aforementioned any one claim, it is characterized in that, the microtexture of this flat product comprises the retained austenite of 10-25 volume %.
12. 1 kinds of methods for the manufacture of the flat product formed according to claim 1 to 11 any one, described method comprises following algorithm:
There is provided primary products with slab, thin plate or casted steel belt mode, it comprises the carbon in % by weight except iron and inevitable impurity: 0.10-0.60%, silicon: 0.4-2.5%, aluminium: up to 3.0%, manganese: 0.4-3.0%, nickel: up to 1.0%, copper: up to 2.0%, molybdenum: up to 0.4%, chromium: up to 2%, cobalt: up to 1.5%, titanium: up to 0.2%, niobium: up to 0.2%, vanadium: up to 0.5%;
Primary products described in hot rolling to form hot rolled strip in one or more roll path, and wherein, the hot rolled strip obtained has the hot rolling end temp of at least 830 DEG C when it leaves last roll path;
The hot rolled strip that the gained that reels under the coiling temperature between these hot rolling end temp and 560 DEG C arrives;
This hot rolled strip cold rolling has the cold-rolled steel strip of at least 30% cold rolling degree to be formed;
The cold-rolled steel strip that thermal treatment obtains, wherein, in described heat treated process, this cold-rolled steel strip
-be heated to the annealing temperature reaching at least 800 DEG C,
-be cooled to maintenance temperature with the rate of cooling of at least 8 DEG C/s from this annealing temperature, this maintenance temperature is positioned at and keeps temperature range, this maintenance temperature range has 470 DEG C of upper limits and has the lower limit higher than martensite start temperature MS, from this martensite start temperature, martensite is formed in the microtexture of this cold-rolled steel strip, and
-at this maintenance temperature, be kept for some time of being enough to form at least 20 volume % bainites in the microtexture of cold-rolled steel strip.
13. described methods according to claim 12, is characterized in that, this hot rolling end temp is 850-950 DEG C.
14. according to the described method of one of claim 12 and 13, and it is characterized in that, this maintenance temperature is 300-420 DEG C.
15. according to claim 12 to the described method of 14 any one, it is characterized in that, this cold-rolled steel strip is coated with coat of metal after heat treatment.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP12178332.8A EP2690184B1 (en) | 2012-07-27 | 2012-07-27 | Produit plat en acier laminé à froid et son procédé de fabrication |
| EP12178332.8 | 2012-07-27 | ||
| PCT/EP2013/065838 WO2014016421A1 (en) | 2012-07-27 | 2013-07-26 | Cold-rolled flat steel product and method for the production thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN104641008A true CN104641008A (en) | 2015-05-20 |
| CN104641008B CN104641008B (en) | 2016-11-30 |
Family
ID=
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106917055A (en) * | 2017-03-17 | 2017-07-04 | 北京科技大学 | A kind of third generation tough automobile steel high and preparation method thereof |
| CN107541665A (en) * | 2016-06-27 | 2018-01-05 | 韩国机械硏究院 | Include the steel of film-form retained austenite |
| CN112789358A (en) * | 2018-09-26 | 2021-05-11 | 蒂森克虏伯钢铁欧洲股份公司 | Method for producing a coated flat steel product and coated flat steel product |
| CN114774651A (en) * | 2022-04-18 | 2022-07-22 | 营口中车型钢新材料有限公司 | Heat treatment design of YZ25SiMnMoV flat steel for railway bearing |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1729307A (en) * | 2002-12-20 | 2006-02-01 | 于西纳股份有限公司 | A steel composition for the production of cold rolled multiphase steel products |
| JP2009209451A (en) * | 2008-02-08 | 2009-09-17 | Jfe Steel Corp | High-strength hot-dip galvanized steel sheet excellent in workability and process for production thereof |
| KR20100025928A (en) * | 2008-08-28 | 2010-03-10 | 현대제철 주식회사 | High strength hot- dip galvanized steel sheet having excellent formability and galvanizing property, and method for producing the same |
| CN102149841A (en) * | 2008-09-10 | 2011-08-10 | 杰富意钢铁株式会社 | High-strength steel sheet and method for production thereof |
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1729307A (en) * | 2002-12-20 | 2006-02-01 | 于西纳股份有限公司 | A steel composition for the production of cold rolled multiphase steel products |
| JP2009209451A (en) * | 2008-02-08 | 2009-09-17 | Jfe Steel Corp | High-strength hot-dip galvanized steel sheet excellent in workability and process for production thereof |
| KR20100025928A (en) * | 2008-08-28 | 2010-03-10 | 현대제철 주식회사 | High strength hot- dip galvanized steel sheet having excellent formability and galvanizing property, and method for producing the same |
| CN102149841A (en) * | 2008-09-10 | 2011-08-10 | 杰富意钢铁株式会社 | High-strength steel sheet and method for production thereof |
Non-Patent Citations (1)
| Title |
|---|
| 居殿春 等: "残余奥氏体对TRIP钢机械性能的影响", 《冶金丛刊》 * |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107541665A (en) * | 2016-06-27 | 2018-01-05 | 韩国机械硏究院 | Include the steel of film-form retained austenite |
| CN107541665B (en) * | 2016-06-27 | 2020-07-03 | 韩国机械硏究院 | Steel material containing film-like retained austenite |
| CN106917055A (en) * | 2017-03-17 | 2017-07-04 | 北京科技大学 | A kind of third generation tough automobile steel high and preparation method thereof |
| CN112789358A (en) * | 2018-09-26 | 2021-05-11 | 蒂森克虏伯钢铁欧洲股份公司 | Method for producing a coated flat steel product and coated flat steel product |
| CN114774651A (en) * | 2022-04-18 | 2022-07-22 | 营口中车型钢新材料有限公司 | Heat treatment design of YZ25SiMnMoV flat steel for railway bearing |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2015528065A (en) | 2015-09-24 |
| EP2690184A1 (en) | 2014-01-29 |
| US20150218684A1 (en) | 2015-08-06 |
| WO2014016421A1 (en) | 2014-01-30 |
| JP6202579B2 (en) | 2017-09-27 |
| EP2690184B1 (en) | 2020-09-02 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP7275137B2 (en) | Steel plate with excellent toughness, ductility and strength and method for producing the same | |
| CA2954141C (en) | Method for producing a high strength steel sheet having improved strength, ductility and formability | |
| CN103314120B (en) | Process for producing hot stamp molded article, and hot stamp molded article | |
| CN106133173B (en) | The excellent high strength cold rolled steel plate of property uniform in material and its manufacture method | |
| JP6623183B2 (en) | Method for producing high strength coated steel sheet with improved strength, ductility and formability | |
| JP6093702B2 (en) | Cold rolled flat steel product made from multiphase steel and its manufacturing method | |
| US20150203946A1 (en) | Hot-Rolled Flat Steel Product and Method For the Production Thereof | |
| JP6202579B2 (en) | Cold rolled flat steel product and method for producing the same | |
| CN108431279A (en) | Automotive part with high intensity and excellent durability and its manufacturing method | |
| KR101848876B1 (en) | Multi-phase steel, cold-rolled flat product which is produced from a multi-phase steel of this type, and method for producing it | |
| JP6846522B2 (en) | High-strength cold-rolled steel sheets with excellent yield strength, ductility, and hole expansion properties, hot-dip galvanized steel sheets, and methods for manufacturing these. | |
| JP6343688B2 (en) | Method for producing ultra-high strength coated or uncoated steel sheet and the resulting steel sheet | |
| KR20150023566A (en) | Steel, sheet steel product and process for producing a sheet steel product | |
| CN104520460A (en) | Cold-rolled steel sheet, method for producing same, and hot-stamp-molded article | |
| US20140261914A1 (en) | Method of producing hot rolled high strength dual phase steels using room temperature water quenching | |
| US10472692B2 (en) | Method for manufacturing a high strength steel sheet having improved formability and ductility and sheet obtained | |
| CN102581008A (en) | Processing method for producing low-cost high-formability IF (interstitial-free) steel | |
| EP3164518A2 (en) | Method for producing a high strength steel sheet having improved strength and formability and obtained sheet | |
| US20160201157A1 (en) | Method for producing a steel component | |
| KR20160079467A (en) | Hot stamping product and method of manufacturing the same | |
| EP3887556B1 (en) | Cold rolled annealed steel sheet with high hole expansion ratio and manufacturing process thereof | |
| CN107541663A (en) | A kind of beverage can ferrostan and its production method | |
| WO2012172185A1 (en) | Method for manufacturing a medium carbon steel product and a hot rolled medium carbon steel product | |
| CN104641008B (en) | Flat cold-rolled bar product and manufacture method thereof | |
| TW202120711A (en) | Method for increasing spheroidization rate of chrome molybdenum steel material |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20161130 Termination date: 20210726 |
|
| CF01 | Termination of patent right due to non-payment of annual fee |