CN104278206A - Steel plate with thickness of smaller than 60mm and yield strength of 690MPa and preparation method of steel plate - Google Patents
Steel plate with thickness of smaller than 60mm and yield strength of 690MPa and preparation method of steel plate Download PDFInfo
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- CN104278206A CN104278206A CN201410546964.6A CN201410546964A CN104278206A CN 104278206 A CN104278206 A CN 104278206A CN 201410546964 A CN201410546964 A CN 201410546964A CN 104278206 A CN104278206 A CN 104278206A
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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
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/32—Ferrous alloys, e.g. steel alloys containing chromium with boron
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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
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C33/00—Making ferrous alloys
- C22C33/04—Making ferrous alloys by melting
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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
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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
- C22C38/04—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
- C22C38/12—Ferrous alloys, e.g. steel alloys containing tungsten, tantalum, molybdenum, vanadium, or niobium
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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
- C22C38/16—Ferrous alloys, e.g. steel alloys containing copper
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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
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
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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
- C21D2211/002—Bainite
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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
- C21D2211/008—Martensite
Abstract
The invention belongs to the field of steel and iron and particularly relates to a steel plate with the thickness of smaller than 60mm and the yield strength of 690MPa. The steel plate contains the following chemical components in percentage by weight: 0.10-0.20% of C, 0.15-0.50% of Si, 1.00-1.60% of Mn, 0.10-0.60% of Cr, 0.015-0.050% of Als, 0.008-0.025% of Ti, 0.10-0.30% of Mo, 0.0008-0.0030% of B, less than or equal to 0.025% of P, less than or equal to 0.008% of S, less than or equal to 40ppm of N, less than or equal to 20ppm of O, less than or equal to 2ppm of H and the balance of Fe and unavoidable impurities. The steel plate provided by the invention has favorable mechanical properties, plasticity and toughness, has the yield strength of larger than or equal to 690MPa, and can be applied to manufacture of large engineering machines or steel structures such as hydraulic supports for coal mines, heavy engineering machines, ocean platforms and the like.
Description
Technical field
The invention belongs to iron and steel technical field, particularly, the present invention relates to a kind of thickness 60mm with lower yield strength 690MPa level steel plate and preparation method thereof.
Background technology
Along with the industries such as domestic Steel Structure Industry, engineering machinery, mining machinery are flourish, simultaneously for complying with the market demand trend that the engineering machinery such as hoisting machinery, excavator boom beam, mine hydraulic support maximize, height is strengthened, the demand for yield strength 690MPa level High Strength Steel Plate is day by day strong.This intensity rank steel plate, domestic steel mill generally adopts out-line quenching+tempering (i.e. modifier treatment) mode to produce, this production technique not only increases facility investment, and operation is various, organization of production scheduling difficulty, the production cycle is long, and production process cost is high, the steel plate cost of alloy simultaneously developed under this kind of process system is higher, causes high-strength steel economic benefit not good.For reducing production cost, domestic also have the report adopting Micro Alloying treatment process to produce high tensile steel plate.
In Chinese patent CN101215624B, disclose a kind of press quenching producing and manufacturing technique of high toughness thick steel plate, in the Composition Design of steel, adopt Cr-Cu-Ni-Mo-V-Nb-Ti-B compound to add, the yield strength of steel is at below 565MPa, and tensile strength is at below 645MPa.Although this patent provides and a kind ofly rolls rear press quenching production technique based on aerosol and the water curtain two benches type of cooling, but weak point is the mechanical property only disclosing thickness 32mm steel plate, and component system is complicated, cost of alloy is higher, intensity is too low, fail to give full play to the effect of press quenching Quick high strength.
In Chinese patent CN102230057B, disclose a kind of method adopting direct quenching explained hereafter petroleum storage tank steel plate for ultra, in the Composition Design of steel, adopt Ni-Mo-V-Nb-Ti-Ca-B compound to add, the yield strength of steel is at below 604MPa, and tensile strength is at below 686MPa.Which disclose and adopt direct quenching explained hereafter thickness 12 ~ 45mm steel plate, but intensity is equally too low.
In Chinese patent CN102851604A, disclose a kind of production method of yield strength 690MPa grade high-strength steel plate, slab adopts press quenching (DQ)+tempering (T) explained hereafter after controlled rolling, in the Composition Design of steel, adopt Cr-Mo-V-Nb-Ti-B compound to add, owing to being the design of low-carbon (LC) component system, need the ferromanganese of interpolation high level, ferro-niobium and ferro-vanadium, cause cost of alloy higher.
In Chinese patent CN101328564B, disclose a kind of low yield ratio HT 780 steel plate and the manufacture method thereof with superior weldability, in the Composition Design of steel, adopt Cu-Ni-Mo-V-Nb-Ti-Ca-B compound to add, the yield strength of steel is at below 686MPa.Not only intensity is low to which disclose the steel plate adopting direct quenching explained hereafter, and follow-uply also needs normalizing and tempering heat treatment step, complex manufacturing, alloy and process cost high.
Find after prior art analysis, in disclosed document the yield strength of most of steel plate not higher than 690MPa, or yield strength reaches 690MPa, but noble metal content is high or the complicated production cost that causes of thermal treatment process is higher, or fails to realize industrial production; Meanwhile, for while yield strength reach 690MPa level High Strength Steel Plate, do not find only to carry out one heat treated production technique of off-line.
Summary of the invention
The object of the present invention is to provide a kind of thickness 60mm with lower yield strength 690MPa level High Strength Steel Plate and reduce production method thereof, by the control to chemical composition, rolling technology, process for cooling and tempering heat treatment process, obtaining a kind of in steel plate is main tissue by ferrite bainite/martensite, achieves the production of yield strength 690MPa level High Strength Steel Plate; Simultaneously by the innovative development to rolling and process for cooling model, achieve after steel plate rolls and save out-line quenching operation, only carry out one off-line tempering heat treatment, reduce organization of production difficulty, reduce production process, shorten the production cycle.
Thickness 60mm of the present invention is with lower yield strength 690MPa level steel plate, its chemical composition comprises by weight percentage: C:0.10% ~ 0.20%, Si:0.15% ~ 0.50%, Mn:1.00% ~ 1.60%, Cr:0.10% ~ 0.60%, Als:0.015% ~ 0.050%, Ti:0.008% ~ 0.025%, Mo:0.10% ~ 0.30%, B:0.0008% ~ 0.0030%, P≤0.025%, S≤0.008%, N≤40ppm, O≤20ppm, H≤2ppm, and all the other are iron and inevitable impurity; Wherein, Als represents dissolved aluminum.
Steel plate tissue of the present invention is main composition by ferrite bainite and martensite, and its yield strength is more than or equal to 690MPa.
Below thickness 60mm according to the present invention is described in detail with the chemical composition of lower yield strength 690MPa level High Strength Steel Plate.
C:C is topmost solution strengthening element, can significantly improve the hardening capacity of steel, conclusive effect is play to the intensity of martensitic steel and hardness, but the increase of carbon content makes the plasticity of steel and impelling strength reduce, cold short proneness and timeliness proneness improve, and worsen welding property.Additionally must increase other valuable microalloy content guarantee hardness of steel while considering carbon drop, and this will cause cost to increase considerably, and consider and control the sufficient quantity of C 0.10% ~ 0.20%.
Si:Si enters ferrite and plays solution strengthening effect, but Si can improve the ductile-brittle transition temperature of steel significantly, and also can worsen plasticity and welding property, therefore, the sufficient quantity of Si controls 0.15% ~ 0.50% simultaneously.
Mn:Mn can reduce critical transition temperature Ar3, significantly improves the hardening capacity of steel, has certain solution strengthening effect simultaneously, plays and improves the intensity of steel and the effect of hardness.Because manganese and sulphur have larger avidity, MnS has certain plasticity when high temperature, avoids the hot-short of steel, but too high Mn can affect the welding property of steel, also can aggravate the center segregation of strand, causes product banded structure serious, and then has influence on impelling strength.Therefore, the sufficient quantity of Mn controls 1.00% ~ 1.60%.
P:P belongs to low temperature brittleness element, and P significantly expands the two-phase region between liquid phase and solid phase, and in steel process of setting, segregation is between crystal grain, form high phosphorus brittle layer, improve the rank of banded structure, make the local organization of steel abnormal, cause mechanical property uneven, reduce the plasticity of steel, make steel easily produce brittle crack, erosion resistance declines, and also has disadvantageous effect to welding property, increase welding crack sensibility, so the content of phosphorus in steel should be reduced as far as possible.Consider production cost, the content of P is controlled below 0.025%.
S: when S is present in steel with the form of FeS, if S content Gao Zeyi produces hot-short phenomenon.When S is present in steel with the form of MnS, S often distributes along rolling direction with bar form, forms serious banded structure, destroy the continuity of steel, also can produce material impact to the performance of steel different directions, reduce plasticity and the impelling strength of steel, improve ductile-brittle transition temperature.Therefore, the content of S is controlled below 0.008%.
Cr:Cr can prevent the greying tendency adding Mo steel, and belong to stable austenite element, greatly can improve the hardening capacity of steel, improve the intensity of steel, but too high Cr can reduce the welding property of steel, considers, the sufficient quantity of Cr controls 0.10 ~ 0.60%.
The crystal grain of Al:Al energy refinement steel, improves the intensity of steel, also can improve impelling strength simultaneously.Because A1 and N has stronger avidity, can also eliminate the aging sensitivity that N element causes, therefore, the content of Als is decided to be 0.015% ~ 0.050%.
Ti:Ti can separate out TiN particle under 1200 ~ 1300 DEG C of high temperature, as the precipitation core of Nb (C, N), thus can reduce the quantity of fine niobium precipitate, and then reduces the crack sensitivity of Nb bearing steel.Ti can form carbide, the nitride particles of tiny titanium, by stoping the alligatoring of austenite crystal thus obtaining comparatively tiny austenitic microstructure in heating of plate blank process.Ti and N combines and generates stable high diffusive compound, not only can eliminate the free nitrogen in steel, and can control grain-size in the heat affected zone when hot procedure and welding, improves the low-temperature flexibility at each position of steel construction.Excessive Ti will form the liquation TiN of micron order size, not only cannot crystal grain thinning, can worsen steel plate toughness on the contrary.Therefore, the sufficient quantity of Ti controls 0.008% ~ 0.025%.
Mo:Mo is present in solid solution phase and Carbide Phases in steel, belong to stable austenite element, greatly can improve the hardening capacity of steel, C curve can be moved to right strongly, to promote that bainite/martensite changes, steel belt roof bolt fragility can be improved simultaneously, greatly improve the low-temperature flexibility of steel, improve the resistance for delayed fracture of steel.Comprehensive cost factor, the sufficient quantity of Mo controls 0.10% ~ 0.30%.
The strong segregation of B:B, in austenite grain boundary and other lattice defect place, can increase the hardenability of steel, improves the hardening capacity of steel.Add the forming core that micro-B can obviously suppress ferrite on austenite grain boundary, ferritic transformation curve is obviously moved to right, to promote that bainite/martensite changes, but Boron contents is more than 0.0030%, and rear above-mentioned effect reaches capacity, but also may be formed various to hot workability and toughness disadvantageous containing B precipitated phase, consider, Boron contents should control 0.0008% ~ 0.0030%.
N:N too high levels can worsen the impelling strength of high-strength steel, and general control is at below 40ppm.
O:O too high levels shows that steel inclusion is too many, all can produce adverse influence, therefore O content should control at below 20ppm as far as possible, to improve Cleanliness of Molten Steel to every mechanical property of steel.
H:H is for the high-strength steel that yield strength is greater than 690MPa, and harm is comparatively large, easily causes flaw detection not conform to, and affects low-temperature impact toughness, need to be controlled at below 2ppm by means such as vacuum-treat.
The present invention is directed to the steel plate of different thickness, in conjunction with the concrete production technique of each specification, optimize Composition Design.Along with thickness increases, consider that the through hardening ability of steel plate Cooling Process declines to some extent, more the yield strength of Plate Steel will reach 690MPa rank, each hardening capacity element needs raising in various degree, as Cr and Mo, under guaranteeing strong cool condition, C curve moves to right, and forms the hard phase constitution of more bainite/martensite in steel plate, but for improving the impelling strength of thick steel plates, carbon content should suitably reduce, Mo content suitably increases simultaneously, thin specification steel plate can utilize the advantage that process of cooling heat conduction efficiency is higher, make steel plate full thickness can through hardening, therefore, thinner steel plate will reach same intensity rank, alloy content can suitably reduce, especially for noble metal element, lower content can obviously reduce steel plate cost of alloy, the compression ratio that thin specification steel plate is total is simultaneously larger, crystal grain is refinement more, impelling strength is also relatively more secure, therefore, C content also can suitably improve, under the prerequisite ensureing steel plate obdurability rational Match, expensive element is replaced with cheap element, reduce the cost of alloy of steel plate further, improve product competitiveness in the market.
In addition, present invention also offers a kind of thickness 60mm with the reduce production method of lower yield strength 690MPa level High Strength Steel Plate, described manufacture method comprises smelting, casting, heating, rolling, cooling and tempering.
Particularly, above-mentioned thickness 60mm of the present invention, with the preparation method of lower yield strength 690MPa level High Strength Steel Plate, comprises the following steps:
(1) smelt and cast;
(2) heat: to the heating steel billet obtained after casting, steel billet tapping temperature controls at 1150 ~ 1230 DEG C;
(3) rolling: the rough rolling of steel billets after step (2) heating obtains intermediate blank, and workpiece thickness is 2.0 ~ 4.0 times of finished product thickness, and steel billet finish rolling start rolling temperature is 900 ~ 1100 DEG C, and finishing temperature is 850 ~ 940 DEG C;
(4) cool: opening cold temperature is 750 ~ 830 DEG C, and final cooling temperature is not higher than 300 DEG C, and speed of cooling is 5 ~ 50 DEG C/s;
(5) temper: tempering temperature is 570 ~ 640 DEG C, tempering insulation time is 8 ~ 45min.
Above-mentioned smelting and casting: adopt converter or electrosmelting, casting adopts continuous casting or die casting.
Above-mentioned preparation method, adopts plate mill or Steckel mill rolling:
Heating temperature before (a) rolling: steel billet tapping temperature controls at 1150 ~ 1230 DEG C.In During Controlled Rolling, the effect such as precipitation strength in austenite recrystallization, rolling and roller repairing process is postponed in order to give full play to Ti microalloy element, should ensure that microalloy element is more solidly soluted in austenite, billet heating temperature gives full play to its solid solution advantage, so at least should improve more than 1150 DEG C; Consider that Heating temperature is too high, austenite crystal will too be grown up simultaneously, and is genetic to and rolls rear steel plate, can cause detrimentally affect, therefore should ensure that steel billet tapping temperature controls below 1230 DEG C as far as possible to steel plate impelling strength.
(b) rolling condition: workpiece thickness is 2.0 ~ 4.0 times of finished product thickness, and steel billet finish rolling start rolling temperature is 900 ~ 1100 DEG C, and finishing temperature is 850 ~ 940 DEG C.Steel billet obtains intermediate blank after roughing mill rolling, on roller-way after temperature to target start rolling temperature, carries out finish rolling.Finishing stands is for improving milled sheet shape, to alleviate the Strip Shape Control difficulty of follow-up strong water-cooled, suitably can improve finish rolling start rolling temperature to reduce rolling drag, finish rolling start rolling temperature also will be avoided too high simultaneously, austenite recrystallization is too fast, roll rear steel plate mixed crystal seriously on the impact of steel plate impelling strength, therefore finish rolling start rolling temperature can not higher than 1100 DEG C, before avoiding steel plate to enter water, there is too much proeutectoid ferrite transformation simultaneously, to ensure that steel plate tissue cold is directly transformed into bainite/martensite tissue by austenite through strong, in conjunction with the effect of microalloy carbonitride pinning dislocation, bainite/martensite lath group grain-size after common refinement steel plate cooling, quick raising thick steel plates intensity, therefore finish rolling start rolling temperature can not lower than 900 DEG C.
By depressing rolling greatly, austenite crystal, in flattening and elongated condition, along with the increase of draught, produces a large amount of slip band and dislocation in crystal grain, increase effective grain boundary area, increase phase transformation thinning effect, improve the obdurability of steel, consider that steel plate should ensure enough draught of rough rolling step simultaneously, with even refinement section of steel plate tissue, improve steel plate low-temperature impact toughness, consider, workpiece thickness should control 2.0 ~ 4.0 times at finished product thickness.
C () cooling conditions: opening cold temperature is 750 ~ 830 DEG C, final cooling temperature is not higher than 300 DEG C, and speed of cooling is 5 ~ 50 DEG C/s.In this invention Plate Production process, for guaranteeing that steel plate is organized substantially based on austenite before entering water, in the strong cold process of steel plate, austenite is directly transformed into bainite/martensite, armor plate strength level is improved fast by online strong cold means, therefore for avoiding the formation of too much soft phase (proeutectoid ferrite) in matrix, cold temperature opened by steel plate must not lower than 750 DEG C; Consider and need about the 10 seconds time of traveling on roller-way to entering water front spring after rolling, if now steel billet temperature is too high, the phenomenon that strain inducing austenite structure recrystallize, partial, re-crystallization or subgrain are replied may be there is after rolling, steel plate is caused to enter coarse grains before water, affect the low-temperature flexibility of slab, therefore steel plate open cold temperature must not higher than 830 DEG C.
Consider that final cooling temperature is too high, bainite/martensite phase transformation is incomplete, and armor plate strength is difficult to significantly improve fast, therefore final cooling temperature controls below 300 DEG C.
Along with the increase of speed of cooling, promote that austenite is to the transformation of cryo tissue, improve the hard phase constitution volume fraction of ferrite bainite/martensite, thus realize armor plate strength and significantly promote, consider that Plate Steel thermal conduction capability is limited simultaneously, consider, speed of cooling controls within the scope of 5 ~ 50 DEG C/s.
(d) tempering: by implementing rational tempering heat treatment to steel plate, effective uniform formation, improves the plasticity and toughness of steel plate, promotes the abundant precipitation of Secondary phase particle simultaneously, play the precipitation strength effect of microalloy element in steel, guarantee that steel plate obtains stable intensity, plasticity and toughness index.Consider, tempering temperature controls within the scope of 570 ~ 640 DEG C, and tempering insulation time controls within the scope of 8 ~ 45min.
Steel plate of the present invention has high strength, excellent plasticity and toughness and production technique can realize minimizing, and with low cost, energy-conservation environmental protection, is applicable to promote the use of.
Particularly, the invention has the advantages that:
(1) steel of the present invention rolls and directly carries out tempering heat treatment afterwards, and without the need to carrying out out-line quenching, comparing traditional hardening and tempering process can simplify production process, significantly reduces production cost, and also obviously can shorten the delivery cycle, comprehensive benefit is remarkable simultaneously;
(2) require looser to phosphorus content, greatly can reduce smelting cost, simultaneously during alloying, cheap high carbon ferromanganese can be adopted to replace low carbon ferromanganese, and by carrying out reasonably optimizing to composition, eliminate Nb, Ni and V noble metal, in conjunction with the enforcement of rolling rear ultra-rapid cooling technique, significantly reduce the cost of alloy of steel grade;
(3) roll rear ultra-rapid cooling technique and greatly can retain the high density dislocation tissue that the operation of rolling produces, for process of cooling phase transformation provides more forming core point, the obvious refinement of matrix, armor plate strength also obtains fast lifting simultaneously;
(4) after the rolling of ultra-rapid cooling, tissue possesses highly stable temper resistance, and in hot-work or welding process, due to the precipitation strength effect of dislocations strengthening and second phase particles, steel plate shows more stable mechanical property.
In sum, the comprehensive mechanical property of steel of the present invention is superior, and easy fracture and destruction, not safe and reliable, can be widely used in the manufacture of the large-scale engineering machinery equipments such as coal mine hydraulic supporting, heavy engineering machinery, ocean platform or steel construction.
Accompanying drawing explanation
Fig. 1 is the microtexture of the embodiment of the present invention 6 steel.
Embodiment
The thickness 60mm that the present invention relates to carries out converter smelting with the chemical composition of lower yield strength 690MPa level High Strength Steel Plate by chemical composition shown in table 1 and pours into continuously cast bloom or ingot casting, heat after continuously cast bloom or ingot formation in process furnace, adopt plate mill or Steckel mill rolling, roll rear steel plate and only carry out one off-line tempering heat treatment.The main technologic parameters such as strand tapping temperature, finishing temperature, final cooling temperature are in table 2.Respective steel plate stretching performance ,-20 DEG C of impact of collision merits, thickness specifications are listed in table 3, and the low-temperature impact toughness of visible steel of the present invention is excellent, and-20 DEG C of longitudinal AKv are not less than 150J.Fig. 1 shows the SEM microtexture photo of embodiment 6 steel, and display organization is ferrite bainite/martensite.
Table 1 below illustrates the chemical composition of the steel according to the embodiment of the present invention 1 to embodiment 8.
The chemical composition (wt.%) of table 1 embodiment of the present invention
Table 2 below shows the main technologic parameters according to the embodiment of the present invention 1 to embodiment 8.
The main production parameter of table 2 embodiment of the present invention
Table 3 shows the Main Mechanical according to the embodiment of the present invention 1 to embodiment 8.
The mechanical property of table 3 embodiment of the present invention
Those of ordinary skill in the art will be appreciated that, above embodiment is only used to the present invention is described, and be not used as limitation of the invention, as long as in spirit of the present invention, all will drop in Claims scope of the present invention the change of the above embodiment, modification.
Claims (4)
1. a thickness 60mm is with lower yield strength 690MPa level steel plate, it is characterized in that, the chemical composition of described steel plate comprises by weight percentage: C:0.10% ~ 0.20%, Si:0.15% ~ 0.50%, Mn:1.00% ~ 1.60%, Cr:0.10% ~ 0.60%, Als:0.015% ~ 0.050%, Ti:0.008% ~ 0.025%, Mo:0.10% ~ 0.30%, B:0.0008% ~ 0.0030%, P≤0.025%, S≤0.008%, N≤40ppm, O≤20ppm, H≤2ppm, and all the other are iron and inevitable impurity.
2. steel plate according to claim 1, is characterized in that, the yield strength of described steel plate is more than or equal to 690MPa.
3. steel plate according to claim 1, is characterized in that, the tissue of described steel plate is primarily of ferrite bainite and martensite composition.
4. the preparation method of arbitrary described steel plate in claim 1-3, comprises the following steps:
(1) smelt and cast;
(2) heat: to the heating steel billet obtained after casting, steel billet tapping temperature controls at 1150 ~ 1230 DEG C;
(3) rolling: the rough rolling of steel billets after step (2) heating obtains intermediate blank, and workpiece thickness is 2.0 ~ 4.0 times of finished product thickness, and steel billet finish rolling start rolling temperature is 900 ~ 1100 DEG C, and finishing temperature is 850 ~ 940 DEG C;
(4) cool: opening cold temperature is 750 ~ 830 DEG C, and final cooling temperature is not higher than 300 DEG C, and speed of cooling is 5 ~ 50 DEG C/s;
(5) temper: tempering temperature is 570 ~ 640 DEG C, tempering insulation time is 8 ~ 45min.
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Cited By (4)
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| CN107058863A (en) * | 2016-12-29 | 2017-08-18 | 山东钢铁股份有限公司 | A kind of 550MPa grades inexpensive steel plate for ocean engineering and its manufacture method |
| CN107723601A (en) * | 2017-11-01 | 2018-02-23 | 山东钢铁股份有限公司 | A kind of residual stress is 50 100MPa wear-resisting steel plate and preparation method thereof |
| CN113172089A (en) * | 2021-03-31 | 2021-07-27 | 甘肃酒钢集团宏兴钢铁股份有限公司 | Production method of high-carbon martensitic stainless steel steckel mill |
| CN114672734A (en) * | 2022-03-31 | 2022-06-28 | 山东钢铁集团日照有限公司 | High-strength steel for welded structure and production method thereof |
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| CN103952643A (en) * | 2014-05-13 | 2014-07-30 | 莱芜钢铁集团有限公司 | Low-yield ratio steel plate with yield strength of 690MPa and preparation method of steel plate |
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| CN1840724A (en) * | 2005-03-30 | 2006-10-04 | 宝山钢铁股份有限公司 | Superhigh strength steel plate with yield strength more than 960Mpa and method for producing same |
| CN102605252A (en) * | 2012-03-30 | 2012-07-25 | 宝山钢铁股份有限公司 | Steel plate with yield strength grade of 1030MPa and manufacturing method thereof |
| CN103060690A (en) * | 2013-01-22 | 2013-04-24 | 宝山钢铁股份有限公司 | High-strength steel plate and manufacturing method thereof |
| CN103952643A (en) * | 2014-05-13 | 2014-07-30 | 莱芜钢铁集团有限公司 | Low-yield ratio steel plate with yield strength of 690MPa and preparation method of steel plate |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN107058863A (en) * | 2016-12-29 | 2017-08-18 | 山东钢铁股份有限公司 | A kind of 550MPa grades inexpensive steel plate for ocean engineering and its manufacture method |
| CN107723601A (en) * | 2017-11-01 | 2018-02-23 | 山东钢铁股份有限公司 | A kind of residual stress is 50 100MPa wear-resisting steel plate and preparation method thereof |
| CN113172089A (en) * | 2021-03-31 | 2021-07-27 | 甘肃酒钢集团宏兴钢铁股份有限公司 | Production method of high-carbon martensitic stainless steel steckel mill |
| CN114672734A (en) * | 2022-03-31 | 2022-06-28 | 山东钢铁集团日照有限公司 | High-strength steel for welded structure and production method thereof |
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Application publication date: 20150114 |