CN104532158A - 800MPa-grade (yield strength) quenched-tempered high-strength steel and production method thereof - Google Patents
800MPa-grade (yield strength) quenched-tempered high-strength steel and production method thereof Download PDFInfo
- Publication number
- CN104532158A CN104532158A CN201410810305.9A CN201410810305A CN104532158A CN 104532158 A CN104532158 A CN 104532158A CN 201410810305 A CN201410810305 A CN 201410810305A CN 104532158 A CN104532158 A CN 104532158A
- Authority
- CN
- China
- Prior art keywords
- tempering
- quenching
- temperature
- steel
- yield strength
- 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.)
- Pending
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
- 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
- C21D8/0247—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
- 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
-
- 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
- C22C38/22—Ferrous alloys, e.g. steel alloys containing chromium 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
- C22C38/24—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
- C22C38/26—Ferrous alloys, e.g. steel alloys containing chromium 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
- C22C38/28—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
- C22C38/32—Ferrous alloys, e.g. steel alloys containing chromium with boron
-
- 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
-
- 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
- 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
- C22C38/54—Ferrous alloys, e.g. steel alloys containing chromium with nickel with boron
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Heat Treatment Of Steel (AREA)
Abstract
The invention relates to 800MPa-grade (yield strength) quenched-tempered high-strength steel and a production method thereof. The steel comprises the following components in percentage by weight: 0.07-0.15% of C, 0.10-0.30% of Si, 0.80-1.60% of Mn, 0.20-0.70% of Cr, 0.10-0.40% of Mo, 0-0.30% of Ni, 0.010-0.030% of Nb, 0.010-0.030% of Ti, 0.010-0.040% of V, 0.0005-0.0030% of B, 0.02-0.06% of Al, 0.001-0.004% of Ca, 0.002-0.005% of N, less than or equal to 0.020% of P, less than or equal to 0.010% of S, less than or equal to 0.008% of O and the balance of Fe and unavoidable impurities, wherein Ceq is represented by the following formula of C+Mn/6+(Cr+Mo+V)/5+(Ni+Cu)/15 and is greater than 0.45% and less than 0.51%; the sum of Mo+0.8Ni+0.4Cr+6V is equal to or greater than 0.7% and less than or equal to 1.1%; the ration of Ti to N is equal to or greater than 3.7 and less than or equal to 7.0 and the ration of Ca to S is equal to or greater than 1.0 and less than or equal to 3.0. The yield strength of the steel is 800-950MPa, the tensile strength is 850-1000MPa, the elongation is greater than 12% and the impact energy at -40 DEG C is greater than 40J, the high strength is achieved and the good elongation and the low-temperature impact toughness are also achieved.
Description
Technical field
The present invention relates to a kind of yield strength 800MPa level quenching and tempering, high and production method thereof.
Background technology
Adopt the component of the mobile equipments such as the girder construction of high strength, easy welding structure steel manufacturing engineering machinery, the arm of lifting machine and the car body of wagon tremie, all can alleviate equipment self-weight, reduce fuel consumption, increase work efficiency.Along with the aggravation of international competition, the component of the mobile equipments such as the car body of high strength easy welded construction steel making harbour machinery, mining machinery, excavator, the girder construction of shovel loader, the arm of lifting machine and wagon tremie is adopted to become trend.Due to engineering machinery high-performance, maximization, light-weighted demand for development, the intensity rank of steel for engineering machinery constantly rises, and is climbed to 700MPa, 800MPa and even more than 1000MPa from 500 ~ 600MPa level.Due to the engineering machinery environment for use of super-high strength steel harshness and stress condition, so have strict requirement to steel product quality, comprise strength property, impact property, buckling performance, welding property and plate shape etc.
At present, the enterprise of the high tensile steel plate of domestic production surrender 800MPa rank is little.Chinese patent 201210209649.5 discloses a kind of production method of tension 800MPa grade high-strength degree steel plate, do not add Ni element, adopt press quenching+tempering process (DQ+T), obtain tempered martensite+tempering lower bainite tissue, its yield strength only has 700MPa.Chinese patent 2011100343384.3 discloses a kind of 750 ~ 880MPa level vehicle high-strength steel and production method thereof, adopts TMCP technique to batch at 560-600 DEG C and produces hot-rolling high-strength steel volume.
Every proportional difference of organizing of the 800MPa level high-strength steel different thickness specification adopting tempered martensite+tempering lower bainite tissue to produce in prior art is comparatively large, and think gauge intensity is lower, easily occurs performance inconsistency.Adopt the precipitation strength type high-strength steel that 560 ~ 600 DEG C of high temperature coilings are produced, by the impact of precipitate granular size and quantity, band steel toe, in, tail strength fluctuation is comparatively large ,-40 DEG C can not be met and impact requirements.
Summary of the invention
The object of this invention is to provide a kind of yield strength 800MPa level quenching and tempering, high and production method thereof, employing hardening and tempering process is produced, the yield strength of this quenching and tempering, high is 800 ~ 950MPa, tensile strength is 850 ~ 1000MPa, unit elongation >12% ,-40 DEG C of ballistic work >40J.
For achieving the above object, technical scheme of the present invention is:
A kind of yield strength 800MPa level quenching and tempering, high, its composition by weight percent is: C:0.07 ~ 0.15%, Si:0.10 ~ 0.30%, Mn:0.80 ~ 1.60%, Cr:0.20 ~ 0.70%, Mo:0.10 ~ 0.40%, Ni:0 ~ 0.30%, Nb:0.010 ~ 0.030%, Ti:0.010 ~ 0.030%, V:0.010 ~ 0.040%, B:0.0005 ~ 0.0030%, Al:0.02 ~ 0.06%, Ca:0.001 ~ 0.004%, N:0.002 ~ 0.005%, P≤0.020%, S≤0.010%, O≤0.008%, all the other are Fe and inevitable impurity; And above-mentioned element needs satisfied following relation simultaneously: 0.45<Ceq<0.51, Ceq=C+Mn/6+ (Cr+Mo+V)/5+ (Ni+Cu)/15; 0.7%≤Mo+0.8Ni+0.4Cr+6V≤1.1%; 3.7≤Ti/N≤7.0; 1.0≤Ca/S≤3.0.
Further, the yield strength of described quenching and tempering, high is 800 ~ 950MPa, and tensile strength is 850 ~ 1000MPa, unit elongation >12% ,-40 DEG C of ballistic work >40J.
Described quenching and tempering, high microstructure be tempered martensite.
In the Composition Design of steel of the present invention:
C: solution strengthening, the intensity of adjustment martensitic stucture and plasticity and toughness, through test after heating quenching, the tensile strength of quenching state low carbon martensite and C content are following relation: Rm=2510C (%)+790 (MPa), Rm is tensile strength, C content can ensure that more than 0.07% quenching state tensile strength is greater than 900MPa, then reduces intensity further by tempering, improves toughness; The higher meeting of C content causes the raising of overall C equivalent, easily cracks during welding.Therefore, C content scope of the present invention is 0.07 ~ 0.15%.
The Si of more than Si:0.10% can play good desoxydatoin, and Si easily produces red iron sheet more than 0.30%, easily worsens the toughness of martensite high-strength steel when Si content is higher.Therefore, Si content range of the present invention is 0.10 ~ 0.30%.
Mn:Mn content can improve the hardening capacity of steel more than 0.8%, and Mn content easily produces the inclusion such as segregation and MnS more than 1.6%, worsens the toughness of martensite high-strength steel.Therefore, Mn content range of the present invention is 0.80 ~ 1.60%.
Cr:Cr content can improve the hardening capacity of steel more than 0.2%, is conducive to forming full martensitic stucture when quenching.Within the scope of tempering temperature 400 ~ 550 DEG C, Cr can form the carbide of Cr, has the effect that anti-average tempering is softening, and Cr content, more than 0.70%, there will be larger spark when welding, affecting welding quality.Therefore, Cr content range of the present invention is 0.20 ~ 0.70%.
The Mo element of more than Mo:0.10% can improve the hardening capacity of steel, is conducive to forming full martensitic stucture when quenching; Under high temperature more than 400 DEG C, Mo can react with C and form compound particle, and have the high-temperature resistant tempered softening effect softening with welding joint, the too high meeting of Mo content causes carbon equivalent to improve, and worsens welding property, and Mo belongs to precious metal simultaneously, can raise the cost.Therefore, Mo content range of the present invention is 0.10 ~ 0.40%.
Ni:Ni element has refinement martensitic stucture, improves the effect of the toughness of steel, and the too high meeting of Ni content causes carbon equivalent to improve, and worsens welding property, and Ni belongs to precious metal simultaneously, can raise the cost.Therefore, Ni content range of the present invention is 0 ~ 0.30%.
Nb, Ti and V:Nb, Ti and V are microalloy element, form nano level precipitate with the element such as C, N, suppress growing up of austenite crystal when heating; Nb can improve non-recrystallization critical temperature Tnr, expanding production window; The tiny precipitate particle that Ti and N reaction is formed can improving welding property; V reacts with N and C and separates out nano level V (C, N) particle in drawing process, can improve the intensity of steel; Nb content range of the present invention is 0.01 ~ 0.03%, Ti content range be 0.01 ~ 0.03%, V content range is 0.01 ~ 0.04%.
B: the B of trace can improve the hardening capacity of steel, and improve the intensity of steel, the B more than 0.0030% easily produces segregation, forms carbon-boron compound, the toughness of severe exacerbation steel.Therefore, B content range of the present invention is 0.0005 ~ 0.0030%.
Al:Al is used as reductor, and the Al adding more than 0.02% in steel can crystal grain thinning, improves impelling strength, and Al content easily produces the oxide inclusion defect of Al more than 0.06%.Therefore, Al content range of the present invention is 0.02 ~ 0.06%.
Ca: in smelting steel process, the micro-Ca element more than 0.001% can play scavenging agent effect, improves the toughness of steel; When Ca content is more than 0.004%, easily forms the compound of larger-size Ca, can toughness be worsened on the contrary.Therefore, Ca content range of the present invention is 0.001 ~ 0.004%.
N: application claims strictly controls the content range of N element.In drawing process, the N element of more than 0.002% can be reacted with V and C and be formed nano level V (C, N) particle, plays the effect of precipitation strength, in welding process, also can resist heat-affected zone softened by precipitation strength; N content easily causes more than 0.005% forming thick precipitate particle, worsens toughness.Therefore, N content scope of the present invention is 0.002 ~ 0.005%.
P, S and O:P, S and O affect the moulding of steel, toughness as impurity element, and the span of control of these four kinds of elements of the present invention is P≤0.02%, S≤0.01%, O≤0.008%.
Carbon equivalent Ceq for quenching and tempering type yield strength 800MPa high-strength steel need meet: 0.45<Ceq<0.51, Ceq=C+Mn/6+ (Cr+Mo+V)/5+ (Ni+Cu)/150, Ceq is too low easily occurs that welding joint softens, the too high easy appearance welding tiny crack of Ceq.
The present invention controls 0.7%≤Mo+0.8Ni+0.4Cr+6V≤1.1%, is mainly used in ensureing that the grade of 800MPa high-strength steel mates welding by force, regulates intensity and the low-temperature flexibility of welded heat affecting zone, reaches the optimum matching with mother metal armor plate strength and low-temperature flexibility.Wherein, Mo, Ni and Cr element can reduce the critical cooling velocity of steel, improves the hardening capacity of steel, improves the intensity of welding joint; Mo at high temperature reacts with C and forms compound, has the effect that opposing welding joint is softening; Mo and Ni element all has thinning microstructure, improves the effect of toughness; V and N reaction generates nano level V (C, N) particle can resist welding joint softened; The collocation of Mo, Ni, Cr and V element can regulate intensity and the toughness of welded heat affecting zone according to strength of parent.The compound addition of application claims Mo, Ni, Cr and V should meet 0.7%≤Mo+0.8Ni+0.4Cr+6V≤1.1%, lower than 0.7% time, the intensity of welding joint and low-temperature flexibility are all lower; Higher than 1.1% time, strength of welded joint is higher, easily produces welding crack.
The present invention controls 3.7≤Ti/N≤7.0, can protect the B atom in steel, makes the abundant solid solution of B, improves hardening capacity.
The present invention controls 1.0≤Ca/S≤3.0, can make the sulfide nodularization of steel grade, improves low-temperature flexibility and the welding property of steel.
The production method of yield strength 800MPa level quenching and tempering, high of the present invention, it comprises the steps:
1) smelt, cast
Adopt converter or Electric furnace steel making by mentioned component, refining, is cast as strand;
2) strand heating
Strand is heated in the stove of 1150 ~ 1270 DEG C, behind strand heart portion to temperature, starts insulation, soaking time >1.5h;
3) rolling
Adopt the reciprocal rolling of single chassis or multi-frame hot continuous rolling that strand is rolled to target thickness, finishing temperature is 820 ~ 920 DEG C, and finishing temperature Tf meets simultaneously: Ar
3<Tf<Tnr, wherein, Ar
3for hypoeutectoid steel austenite starts temperature to ferritic transformation: Ar
3=901-325C-92Mn-126Cr-67Ni-149Mo, Tnr are non-recrystallization critical temperature: Tnr=887+464C+ (6445Nb-644sqrt (Nb))+(732V-230sqrt (V))+890Ti+363Al-357Si; Last passes draft of rolling >15%;
4) cool
Batch in (450-Bs) DEG C temperature range after rolling,
Bs=630-45Mn-40V-35Si-30Cr-25Mo-20Ni, then air cooling is to room temperature;
5) quenching heat treatment
Quenching temperature is Ac
3+ (30 ~ 80) DEG C, Ac
3for austenitic transformation end temp, Ac
3=955-350C-25Mn+51Si+106Nb+100Ti+68Al-11Cr-33Ni-16Cu+67Mo; The Quench heating time is that steel plate heart portion reaches 5 ~ 40min after Heating temperature; Quench cooling rate V>e
(5.3-2.53C-0.16Si-0.82Mn-0.95Cr-1.87Mo-160B)dEG C/s; Be quenched to below (Ms-150) DEG C; Ms is Ms (martensite start) point, Ms=539-423C-30.4Mn-17.7Ni-12.1Cr-11.0Si-7.0Mo; Guarantee obtains full martensitic stucture;
6) tempering heat treatment
Tempering heat treatment: tempering temperature is 400 ~ 550 DEG C, starts insulation after steel plate heart portion reaches furnace temperature, insulation 20 ~ 180min.
In production method of the present invention:
Step of the present invention (2) strand is heated to 1150 ~ 1270 DEG C, heart portion soaking time >1.5h: Heating temperature is greater than 1150 DEG C, heart portion soaking time >1.5h can ensure the abundant solid solution of alloying element; Heating temperature is more than 1270 DEG C, and austenite crystal is excessively grown up, and causes intergranular bonding force to weaken, easily cracks when rolling; Heating temperature easily causes billet surface decarburization more than 1270 DEG C in addition, impacts finished product mechanical property.
The finishing temperature of step of the present invention (3) rolling is greater than Ar
3be to ensure in austenitic area rolling, it is to ensure in the rolling of austenite Unhydrated cement that finishing temperature is less than Tnr, can fining austenite grains and cooled tissue in the rolling of austenite Unhydrated cement.After heat treatment the grain fineness number of steel and toughness have certain heredity, therefore can improve intensity and the toughness of steel after thermal treatment.
Last percentage pass reduction of step of the present invention (3) rolling >15%, heavy reduction rate rolling is to form enough energy of deformation at Unhydrated cement, at Ar
3austenite recrystallization is brought out, crystal grain thinning in ~ Tnr temperature range.
It is to obtain tiny bainite structure that step of the present invention (4) is batched in 450 ~ Bs DEG C of temperature range, improves the toughness of steel.After heat treatment the grain fineness number of steel and toughness have certain heredity, therefore can improve intensity and the toughness of steel after thermal treatment.
Step of the present invention (5) quenching heat treatment: Heating temperature is lower than Ac
3+ 30 DEG C, soaking time is difficult to abundant solid solution lower than 5min alloy; Heating temperature is greater than Ac
3+ 80 DEG C, soaking time is greater than 40min austenite crystal and easily grows up, by controlling quenching temperature and Quench heating time in necessarily narrow scope, can ensure to obtain tiny austenite crystal, thus the martensitic stucture after refinement quenching, improve the obdurability of steel.
Step of the present invention (6) tempering heat treatment: the steel tempering temperature of this component system is more than 400 DEG C and after keeping steel plate heart portion to temperature during more than 20min, the supersaturation carbon atom precipitation in quenched martensite forms spherical Fe
3c cementite, alloy Mo and V can react with C and form tiny alloy carbide at such a temperature, can improve plasticity and the toughness of steel, effectively removes the internal stress of steel simultaneously; Tempering temperature more than 550 DEG C or high soaking time long, spherical Fe
3c cementite and alloy carbide generation alligatoring, can worsen the toughness of steel on the contrary, and reduce the intensity of steel; By adjustment tempering temperature and tempering time can ensure by force, toughness realizes optimum matching.
The relational expression that the present invention relates to:
0.45<Ceq<0.51, Ceq=C+Mn/6+ (Cr+Mo+V)/5+ (Ni+Cu)/15; 0.7%≤Mo+0.8Ni+0.4Cr+6V≤1.1%; 3.7≤Ti/N≤7.0; In 1.0≤Ca/S≤3.0, the symbol of element represents the weight percentage of corresponding element.
The calculation formula that the present invention relates to:
Ar
3＝901-325C-92Mn-126Cr-67Ni-149Mo；
Tnr＝887+464C+(6445Nb-644sqrt(Nb))+(732V-230sqrt(V))+890Ti+363Al-357Si；
Bs＝630-45Mn-40V-35Si-30Cr-25Mo-20Ni；
Ac
3＝955-350C-25Mn+51Si+106Nb+100Ti+68Al-11Cr-33Ni-16Cu+67Mo；
e
(5.3-2.53C-0.16Si-0.82Mn-0.95Cr-1.87Mo-160B)；
Ms＝539-423C-30.4Mn-17.7Ni-12.1Cr-11.0Si-7.0Mo；
In above-mentioned formula, the symbol of element represents weight percentage × 100 of corresponding element.
Beneficial effect of the present invention:
The present invention adopts controlled rolling and controlled cooling and out-line quenching quenching+tempering technique, chemically the aspect such as Composition Design, mother metal tissue, quenching temperature, tempering Heating temperature controls, ensure while realizing superstrength, obtain the performances such as good unit elongation, low-temperature impact toughness.
Compared with the prior art, adopt the 800MPa high-strength steel of composition of the present invention, explained hereafter to have homogeneous tempered martensite, different thickness specification, coil of strip (steel plate) head, in, tail performance inconsistency is little; Low-temperature impact toughness also improves a lot.
Accompanying drawing explanation
Fig. 1 is the metallographic structure figure of steel embodiment 1 of the present invention;
Fig. 2 is the metallographic structure figure of steel embodiment 3 of the present invention;
Fig. 3 is the metallographic structure figure of steel embodiment 6 of the present invention.
Embodiment
Below in conjunction with embodiment, the present invention will be further described
Adopt 50kg vacuum electric furnace to smelt, the embodiment of composition of steel of the present invention is as shown in table 1.By the steel billet that the pouring molten steel of 50kg electrosmelting becomes 120mm thick, put into electric furnace and heat, adopt multi-pass that billet rolling is become target thickness 10mm.Finishing temperature is 820 ~ 920 DEG C, and finishing temperature Tf meets simultaneously: Ar
3<Tf<Tnr; End percentage pass reduction setting 17%; Roll rear employing section cooling, rolling final cooling temperature span of control is (450 ~ Bs) DEG C, and Bs is bainite start temperature; Quenching heat treatment technique, quenching temperature adopts: austenitic transformation end temp (Ac
3)+(30 ~ 80) DEG C, the Quench heating time is 5 ~ 40min behind steel plate heart portion to temperature; Quench cooling rate V>e
(5.3-2.53C-0.16Si-0.82Mn-0.95Cr-1.87Mo-160B)dEG C/s; Below quench cooled to (Ms-150) DEG C; Tempering heat treatment process: tempering temperature is 400 ~ 550 DEG C, tempering time is that steel plate heart portion reaches 20 ~ 180min after Heating temperature.Concrete technology condition is as shown in table 2.
Steel plate after modifier treatment is carried out longitudinal stretching and impact of collision test.The performance that each test piece is corresponding is as shown in table 3.As shown in Table 3, the present invention can produce the high-strength hardened and tempered steel of more than yield strength 800Mpa, the strong 850 ~ 1000MPa of its tension, unit elongation >12% ,-40 DEG C of ballistic work >40J.
Fig. 1 ~ Fig. 3 gives embodiment 1,3,6 and tests the metallurgical tissue picture of steel, can find out, the metallographic structure of finished steel plate is the shaft-like tempered martensite such as homogeneous, and organizes fine and closely woven.
Claims (6)
1. a yield strength 800MPa level quenching and tempering, high, its composition by weight percent is: C:0.07 ~ 0.15%, Si:0.10 ~ 0.30%, Mn:0.80 ~ 1.60%, Cr:0.20 ~ 0.70%, Mo:0.10 ~ 0.40%, Ni:0 ~ 0.30%, Nb:0.010 ~ 0.030%, Ti:0.010 ~ 0.030%, V:0.010 ~ 0.040%, B:0.0005 ~ 0.0030%, Al:0.02 ~ 0.06%, Ca:0.001 ~ 0.004%, N:0.002 ~ 0.005%, P≤0.020%, S≤0.010%, O≤0.008%, all the other are Fe and inevitable impurity, and above-mentioned element needs satisfied following relation simultaneously: 0.45%<Ceq<0.51%, Ceq=C+Mn/6+ (Cr+Mo+V)/5+ (Ni+Cu)/15, 0.7%≤Mo+0.8Ni+0.4Cr+6V≤1.1%, 3.7≤Ti/N≤7.0, 1.0≤Ca/S≤3.0.
2. yield strength 800MPa level quenching and tempering, high according to claim 1, is characterized in that, the microstructure of described quenching and tempering, high is tempered martensite.
3. yield strength 800MPa level quenching and tempering, high according to claim 1 and 2, it is characterized in that, the yield strength of described quenching and tempering, high is 800 ~ 950MPa, tensile strength is 850 ~ 1000MPa, unit elongation >12% ,-40 DEG C of ballistic work >40J.
4. the production method of yield strength 800MPa level quenching and tempering, high as claimed in claim 1, comprises the steps:
1) smelt, cast
Adopt converter or Electric furnace steel making by composition described in the claims 1, refining, is cast as strand;
2) strand heating
Strand is heated in the stove of 1150 ~ 1270 DEG C, after strand heart portion reaches furnace temperature, starts insulation, soaking time >1.5h;
3) rolling
Adopt the reciprocal rolling of single chassis or multi-frame hot continuous rolling that strand is rolled to target thickness, finishing temperature is 820 ~ 920 DEG C, and finishing temperature Tf meets simultaneously: Ar
3<Tf<Tnr, wherein, Ar
3for hypoeutectoid steel austenite starts temperature to ferritic transformation: Ar
3=901-325C-92Mn-126Cr-67Ni-149Mo, Tnr are non-recrystallization critical temperature: Tnr=887+464C+ (6445Nb-644sqrt (Nb))+(732V-230sqrt (V))+890Ti+363Al-357Si; Last passes draft of rolling >15%;
4) cooling is batched after rolling in (450 ~ Bs) DEG C temperature range, Bs=630-45Mn-40V-35Si-30Cr-25Mo-20Ni, and then air cooling is to room temperature;
5) quenching heat treatment
Quenching temperature is Ac
3+ (30 ~ 80) DEG C, Ac
3for austenitic transformation end temp, Ac
3=955-350C-25Mn+51Si+106Nb+100Ti+68Al-11Cr-33Ni-16Cu+67Mo; The Quench heating time is that steel plate heart portion reaches 5 ~ 40min after Heating temperature; Quench cooling rate V>e
(5.3-2.53c-0.16Si-0.82Mn-0.95Cr-1.87Mo-160B)dEG C/s; Be quenched to below (Ms-150) DEG C; Ms is Ms (martensite start) point, Ms=539-423C-30.4Mn-17.7Ni-12.1Cr-11.0Si-7.0Mo; Guarantee obtains full martensitic stucture;
6) tempering heat treatment
Tempering heat treatment: tempering temperature is 400 ~ 550 DEG C, starts insulation after steel plate heart portion reaches furnace temperature, insulation 20 ~ 180min.
5. the production method of yield strength 800MPa level quenching and tempering, high according to claim 4, is characterized in that, the microstructure of the quenching and tempering, high that this production method obtains is tempered martensite.
6. the production method of the yield strength 800MPa level quenching and tempering, high according to claim 4 or 5, it is characterized in that, the yield strength of the quenching and tempering, high that this production method obtains is 800 ~ 950MPa, tensile strength is 850 ~ 1000MPa, unit elongation >12% ,-40 DEG C of ballistic work >40J.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410810305.9A CN104532158A (en) | 2014-12-19 | 2014-12-19 | 800MPa-grade (yield strength) quenched-tempered high-strength steel and production method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410810305.9A CN104532158A (en) | 2014-12-19 | 2014-12-19 | 800MPa-grade (yield strength) quenched-tempered high-strength steel and production method thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN104532158A true CN104532158A (en) | 2015-04-22 |
Family
ID=52847773
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201410810305.9A Pending CN104532158A (en) | 2014-12-19 | 2014-12-19 | 800MPa-grade (yield strength) quenched-tempered high-strength steel and production method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN104532158A (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107805758A (en) * | 2017-10-24 | 2018-03-16 | 南京钢铁股份有限公司 | A kind of high intensity superior low-temperature toughness hull steel and one steel multistage Technology for Heating Processing |
| CN109972042A (en) * | 2019-04-17 | 2019-07-05 | 北京科技大学 | A kind of yield strength 800MPa grades of Low temperature-resistancorrosion-resistant corrosion-resistant H profile steels and preparation method thereof |
| CN111876687A (en) * | 2020-08-12 | 2020-11-03 | 宝武集团鄂城钢铁有限公司 | Easy-to-weld high-strength steel with excellent low-temperature toughness and tensile strength of 800MPa and production method thereof |
| CN112251671A (en) * | 2020-09-30 | 2021-01-22 | 鞍钢股份有限公司 | Isotropic EH690 steel plate and manufacturing method thereof |
| CN113604736A (en) * | 2021-07-26 | 2021-11-05 | 莱芜钢铁集团银山型钢有限公司 | High-strength medium plate with yield strength of 800MPa and preparation method thereof |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103014545A (en) * | 2011-09-26 | 2013-04-03 | 宝山钢铁股份有限公司 | High-strength steel plate with 900 Mpa-level yield strength and preparation method of steel plate |
-
2014
- 2014-12-19 CN CN201410810305.9A patent/CN104532158A/en active Pending
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103014545A (en) * | 2011-09-26 | 2013-04-03 | 宝山钢铁股份有限公司 | High-strength steel plate with 900 Mpa-level yield strength and preparation method of steel plate |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107805758A (en) * | 2017-10-24 | 2018-03-16 | 南京钢铁股份有限公司 | A kind of high intensity superior low-temperature toughness hull steel and one steel multistage Technology for Heating Processing |
| CN107805758B (en) * | 2017-10-24 | 2019-06-04 | 南京钢铁股份有限公司 | A kind of high intensity superior low-temperature toughness hull steel and one steel multistage heat treatment process |
| KR20200060414A (en) * | 2017-10-24 | 2020-05-29 | 난징 아이론 앤드 스틸 컴퍼니 리미티드 | High-strength marine steel with excellent low-temperature toughness and its one-stage multi-stage heat treatment process |
| KR102222958B1 (en) * | 2017-10-24 | 2021-03-05 | 난징 아이론 앤드 스틸 컴퍼니 리미티드 | High-strength ship steel with excellent low-temperature toughness and its one-gang multi-stage heat treatment process |
| CN109972042A (en) * | 2019-04-17 | 2019-07-05 | 北京科技大学 | A kind of yield strength 800MPa grades of Low temperature-resistancorrosion-resistant corrosion-resistant H profile steels and preparation method thereof |
| CN111876687A (en) * | 2020-08-12 | 2020-11-03 | 宝武集团鄂城钢铁有限公司 | Easy-to-weld high-strength steel with excellent low-temperature toughness and tensile strength of 800MPa and production method thereof |
| CN112251671A (en) * | 2020-09-30 | 2021-01-22 | 鞍钢股份有限公司 | Isotropic EH690 steel plate and manufacturing method thereof |
| CN112251671B (en) * | 2020-09-30 | 2021-12-24 | 鞍钢股份有限公司 | Isotropic EH690 steel plate and manufacturing method thereof |
| CN113604736A (en) * | 2021-07-26 | 2021-11-05 | 莱芜钢铁集团银山型钢有限公司 | High-strength medium plate with yield strength of 800MPa and preparation method thereof |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN104513937A (en) | High-strength steel with yield strength of 800MPa and production method thereof | |
| CN104532157A (en) | 900MPa-1000MPa grade (yield strength) quenched-tempered high-strength steel and production method thereof | |
| CN104513936B (en) | A kind of yield strength 1100MPa grades of quenching and tempering, highs and its production method | |
| CN103352167B (en) | A kind of low yield strength ratio high strength bridge steel plate and manufacture method thereof | |
| CN104532156B (en) | A kind of yield strength 1300MPa grades of quenching and tempering, highs and its production method | |
| CN103882330B (en) | A kind of low yield strength ratio superhigh intensity non-quenched and tempered steel plate and production method thereof | |
| CN105506494A (en) | High-toughness hot-rolled high-strength steel with yield strength being 800 MPa and manufacturing method of high-toughness hot-rolled high-strength steel | |
| CN103422025B (en) | The low yield strength ratio structural steel of yield strength >=690MPa and production method thereof | |
| CN101338400B (en) | High strength low-temperature-used low carbon bainite steel and production process thereof | |
| CN111187990B (en) | Hot-rolled H-shaped steel with yield strength of 500MPa and production method thereof | |
| CN113862558B (en) | Low-cost high-toughness high-strength tempered steel with yield strength of 700MPa and manufacturing method thereof | |
| CN106191678B (en) | With the tensile strength >=1700MPa hot formings steel and production method of medium thin slab Direct Rolling | |
| CN101638755A (en) | High-toughness and ultrahigh-strength wear-resistant steel plate and production method thereof | |
| CN104561827A (en) | High strength steel with yield strength to be 900-1000MPa grade and production method of high strength steel | |
| CN103422021B (en) | Low-yield-ratio structural steel with yield ratio equal to or larger than 550MPa and manufacturing method thereof | |
| CN104032237B (en) | Composite microalloyed high-strength steel forging with tensile strength of 700MPa and production method thereof | |
| CN102796967A (en) | 800 MPa economic corrosion-resistance and high-strength steel plate | |
| CN104532158A (en) | 800MPa-grade (yield strength) quenched-tempered high-strength steel and production method thereof | |
| CN102953000B (en) | A kind of ultrahigh-strength steel plates and manufacture method thereof | |
| CN104532159A (en) | 700MPa-grade (yield strength) quenched-tempered high-strength steel and production method thereof | |
| CN111876687A (en) | Easy-to-weld high-strength steel with excellent low-temperature toughness and tensile strength of 800MPa and production method thereof | |
| CN102676933A (en) | Low-alloy super-strength high-toughness steel plate and production method thereof | |
| CN110358970B (en) | Welded structure bainite high-strength steel with yield strength of 1100MPa and preparation method thereof | |
| CN114015934B (en) | 600 MPa-level hot continuous rolling dual-phase structure axle housing steel and production method thereof | |
| CN101603156B (en) | Manufacture method for manufacturing cantilever steel pipe with high strength and high toughness by using hot-rolling coiled plate |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| EXSB | Decision made by sipo to initiate substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| RJ01 | Rejection of invention patent application after publication | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20150422 |