CN102191430A - Easy welding steel plate with yield strength of 550MPa and high toughness and manufacturing method thereof - Google Patents
Easy welding steel plate with yield strength of 550MPa and high toughness and manufacturing method thereof Download PDFInfo
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- CN102191430A CN102191430A CN 201010129753 CN201010129753A CN102191430A CN 102191430 A CN102191430 A CN 102191430A CN 201010129753 CN201010129753 CN 201010129753 CN 201010129753 A CN201010129753 A CN 201010129753A CN 102191430 A CN102191430 A CN 102191430A
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Abstract
The invention discloses an easy welding steel plate with yield strength of 550MPa and high toughness and a manufacturing method thereof. The steel plate comprises the following chemical components in percentage by weight: 0.05 to 0.08 percent of C, 0.25 to 0.50 percent of Si, 1.65 to 1.90 percent of Mn, 0.03 to 0.07 percent of Nb, 0.03 to 0.07 percent of V, 0.0006 to 0.002 percent of B, 0.01 to 0.04 percent of Al, 0.01 to 0.03 percent of Ti, and the balance of Al and inevitable impurities, wherein the content of Fe accords with the following relation that: Mn is more than or equal to 3.01Si +12.8Nb+6.65V-12.12C and less than or equal to 4.78Si+13.8Nb+12.72V-10.13C. A tissue with a bainite strip serving as a substrate is obtained by a control rolling and control cooling technology. The yield strength of the easy welding thick plate with yield strength is more than 550MPa, the tensile strength is more than 670MPa, the Charpy impact power Akv(-20 DEG C) is more than 150 J, and the sensitivity index Pcm of welding cracks is less than or equal to 0.19 percent. The steel plate has high welding property.
Description
Technical field
The present invention relates to the high-strong toughness steel plate, specifically, the present invention relates to yield strength 550MPa level and easily weld high strength steel plate and manufacture method thereof.
Background technology
Usually adopt two kinds of technology to produce high toughness thick steel plate, promptly modified (quenching+tempering) and controlled rolling and controlled cooling (TMCP) technology.Compare with modified technology, the TMCP technology does not need off-line thermal treatment, has characteristics such as save energy and Production Flow Chart weak point.The development of controlled rolling controlled cooling technology mainly is divided into several stages: before the 1950's, and the beginning of controlled rolling technical study; The sixties in 20th century is to early 1970s, the controlled rolling technical progress; The height of controlled rolling controlled cooling technology progress reached worldwide and popularized so far the later stage seventies 20th century.
In recent years, the wide and heavy plate mill with powerful rolling power at home and abroad is used widely.Powerful rolling application, but make steel plate rolling at lesser temps, a large amount of dislocation desity of accumulative total increases the nucleation rate in the process of cooling in austenite, refinement final tissue.Quickening cooling equipment such as online refrigerating unit OLAC (online accelerate cooling), Super-OLAC and multi-functional ejection-type intermittent type refrigerating unit MULPIC (multi-purpose interrupt cooling) etc. is extensive use of, make the speed of cooling of steel plate increase, stopping cold temperature reduces, promote the structural transformation of steel plate when middle gentle lesser temps, improved steel plate microtexture controllability.Adopt the controlled rolling and controlled cooling technology to realize organizational controls and mechanical property control, the steel plate of producing low cost, easily welding, high tough, short flow process has become the important directions that slab is researched and developed.
The controlled rolling and controlled cooling technology mainly comprises two parts: controlled rolling and controlled chilling.
Controlled rolling is often referred to two stage rolling: rolling under rolling deformation on the non-recrystallization temperature and non-recrystallization temperature.The intermediate blank thickness of two stage rolling, open rolling that subordinate phase is rolling and finishing temperature are the emphasis of controlled rolling and controlled cooling technology.
The speed of cooling in the technology for controlled cooling and the cold temperature of stopping are the processing parameters that needs emphasis control.When adopting the controlled rolling and controlled cooling technology to produce high toughness thick steel plate, because steel plate is in rolling and process of cooling, distortion and cooling temperature inhomogeneous, and processing parameter easily fluctuates in control process, and the composition and the technology controlling and process of steel plate proposed following requirement: but steel plate equal stably manufactured in the finishing temperature of broad; The composition system of steel plate is in the speed of cooling of broad and stop all can obtain in the cold temperature range higher tissue of intensity such as bainite structure etc.
Consider the characteristics of controlled rolling and controlled cooling technology, steel plate need be taken all factors into consideration the different-alloy element and separate out at the carbonitride of steel plate high-temperature zone when composition designs, dynamic recrystallization, inferior dynamic recrystallization, static recrystallize, reply, the strain inducing of carbonitride is separated out in the operation of rolling, phase transformation (ferrite when cooling off continuously, perlite, acicular ferrite, bainite, martensite) influence etc., and take all factors into consideration the interaction of different-alloy element, carry out deep theory and experimental analysis, it is simple just to develop composition, and the high toughness thick steel plate of process window broad.
Welding property is the important use properties of steel plate.According to the ferrous metallurgy industry standard YB/T 4137-2005 of People's Republic of China (PRC) regulation, the trade mark is the steel grade of Q550CF, and the Pcm value need be lower than 0.25%.The welding crack sensibility indices P cm of low welding crack sensitivity steel plate can determine by following formula
Pcm＝C+Si/30+Ni/60+(Mn+Cr+Cu)/20+Mo/15+V/10+5B
After welding crack sensibility indices P cm was the welding of reflection steel, welding joint cold crack occurred and judges index.The Pcm value is low more, illustrates that the welding property of steel plate is good more, and the welding back is not prone to cold crack at the welding joint place.The steel plate that the welding crack sensibility index is low can be realized not preheating or the welding of low preheating temperature, has saved the cost of welding sequence, has saved and has welded the required time, improves the economic benefit and the social benefit of steel sheet product.Be generally and reduce Pcm and guarantee that steel plate has higher intensity and ballistic work, add valuable alloying elements such as Cr, Mo, Ni and Cu in the steel plate, the cost of steel plate is improved.Therefore need exploitation to have simple composition system and have low-welding crack-sensitive exponential steel plate.
Summary of the invention
The object of the present invention is to provide a kind of yield strength 550MPa level easily to weld high strength steel plate and manufacture method thereof, adopting Mn-Nb-V is steel grade, by control thermo-mechanical rolling and cooling technology, and do not have modifier treatment, this steel plate has good low-temperature flexibility and weldability.
For achieving the above object, technical scheme of the present invention is,
Yield strength 550MPa level is easily welded high strength steel plate, its chemical component weight per-cent is: C 0.05～0.08%, Si 0.25～0.50%, Mn 1.65～1.90%, Nb 0.03～0.07%, V0.03～0.07%, B 0.0006～0.002%, Al 0.01～0.04%, Ti 0.01～0.03%, and surplus is Fe and unavoidable impurities; Wherein, the content of Mn should satisfy: 3.31Si+15.8Nb+6.65V-9.12C≤Mn≤4.41Si++13.33Nb+7.72V-7.33C, the yield strength of steel plate greater than 550MPa, tensile strength greater than 670MPa, Xia Shi ballistic work Akv (20 ℃) greater than 150J, welding crack sensibility indices P cm≤0.19%.
Yield strength 550MPa level of the present invention is easily welded the manufacture method of high strength steel plate, comprises smelting, casting, heating, rolling, refrigerating work procedure, it is characterized in that, promptly enters refrigerating work procedure without thermal treatment behind described rolling process; Rollingly be divided into the fs and subordinate phase is rolling, in the described fs operation of rolling, start rolling temperature is 1050～1150 ℃, when rolled piece thickness arrives 2～4 times of Finished Steel plate thickness, treats that on roller-way temperature is to 770～860 ℃; In the described subordinate phase operation of rolling, pass deformation rate is 12～28%, and finishing temperature is 750～800 ℃; In described process of cooling, steel plate is cooled to 400～520 ℃ with the speed of 8～35 ℃/s, air cooling after the water outlet.
Further, the thickness of continuously cast bloom after the casting or steel ingot is not less than 3.5 times of Finished Steel plate thickness.
Again, in described heat-processed, Heating temperature is 1080～1180 ℃, and soaking time is 150～240 minutes.
Air cooling adopts stacking or cold bed cooling.
In addition, Finished Steel plate thickness of the present invention is 15～100mm.
The present invention yield strength 550MPa grade steel plate, microtexture is ultra-fine lath of bainite, has features such as high tenacity and low-welding crack-sensitive, its welding crack sensibility is lower than 0.19%, has good welding property.
In composition design of the present invention:
C, the steel grade of the present invention's development is the bainite type high-strength steel.Carbon content increases, and can cause the refinement of bainite lamella, but can increase the content of cementite and Ma Ao constituent element, and the too high meeting of carbon content causes impelling strength to descend.Carbon content is low excessively, and the diffusion phase transformation is become easily, causes the bainite lamella thick, and intensity reduces.For guaranteeing tensile strength and ballistic work, C content of the present invention is controlled to be 0.05～0.08%.
Si, Si do not form carbide, are solid-solubilized in the bainite ferrite, hinder the motion of mobile dislocation, improve the intensity of steel plate.But too high Si content can make ballistic work reduce the welding property variation.Si content among the present invention is controlled to be 0.25～0.50%.
Mn, Mn are austenite stabilizer element, and in the bainitic transformation process of steel grade that the present invention develops, Mn has played the effect that hinders bainite ferrite diffusion motion interface, refinement the bainite ferrite lath.Be solid-solubilized in the effect that Mn in the bainite ferrite matrix has played solution strengthening.Therefore, add 1.65～1.90% Mn among the present invention, help forming the bainite structure of refinement, make steel have good obdurability.
The be significantly increased effect of recrystallization temperature of Nb, Nb.Add the Nb of certain content in the steel plate, recrystallize fully takes place in the time of can making the steel plate fs rolling, refine austenite crystal grain, the hardening capacity of increase steel plate can be produced the bigger steel plate of thickness.Nb belongs to valuable alloying element, the higher cost that can increase steel plate of Nb content.In the higher steel of Mn content, the higher continuous casting steel billet that then may cause of Nb content cracks.Therefore, add 0.03～0.07%Nb among the present invention with control steel plate microtexture and mechanical property.
V can play the effect of solution strengthening in steel, on the other hand, V separates out the motion that can hinder dislocation when lesser temps is rolling, and making has a large amount of dislocations in the austenite, promoted the bainite forming core, refinement bainite finally organize.Add 0.03～0.07% V among the present invention to guarantee that steel plate has higher yield strength after tempering.
Ti, Ti can form TiN, Ti in steel refrigerative different steps
2C
2S
4And TiC, but trickle precipitate refine austenite tissue, inhibition austenite abnormality is grown up, and forms thick austenite crystal.Ti is a ferrite former, and when being present in the ferrite with the solid solution attitude, its strengthening effect is better than Al, Mn, Ni and Mo etc. a little less than Cu and Si.Ti content among the present invention is controlled at 0.01～0.03%.
Al, aluminium is decided the nitrogen agent as deoxidation when steel-making, and crystal grain thinning, improves steel toughness at low temperatures.Though Al and carbon can form Al
4C
3And Al
3C, but therefore the binding ability of Al and carbon does not generally form carbide less than the binding ability of Fe and C.Al in the steel is by forming the AlN crystal grain thinning of small and dispersed.When the solid solution aluminium content in the steel surpasses when a certain amount of, the alligatoring of growing up easily all the better of the austenite crystal of steel.Add the Al crystal grain thinning that is no more than 0.04wt.% among the present invention, improve the toughness of steel plate and guarantee its welding property.
B, the add-on of B is 0.0006～0.0020% among the present invention.
Adopt the chemical ingredients of the present invention's design, superiority is to adopt Mn-Nb-V composition system, does not add valuable alloying elements cr, Mo, Ni and Cu etc.Make full use of the effect of alloying element Mn in the composition design, the proportioning of rational Mn element and C, Si, other elements such as Mn, V is provided, all can form the tissue with good obdurability in the cooling range of broad, producing maximum ga(u)ge is the steel plate of 80mm.
In manufacture method of the present invention:
1, rolling employing two stages controlled rolling technology, the fs distortion is adopted rolling at comparatively high temps, makes recrystallize, refine austenite crystal grain fully take place in the austenite.When being rolled down to 2～4 times of steel plate target thickness, intermediate blank is treated the temperature cooling on roller-way.Rolling postcooling promptly begins rolling to the finish rolling start rolling temperature of subordinate phase.The control of finish rolling start rolling temperature is relevant with thickness of slab.Because thicker intermediate blank is when cooling, it is bigger that surface temperature is lower than steel plate core temperature degree, the dislocation motion ability that forms when rolling is stronger, can reduce and roll the austenitic dislocation desity in back, higher internal temperature can cause surface of steel plate to return temperature simultaneously, and is therefore lower than the finish rolling start rolling temperature of Plate Steel.Fast than steel sheet speed of cooling when subordinate phase is rolling, can be in higher temperature open rolling.In the subordinate phase operation of rolling, lower finishing temperature and bigger deformation rate help forming a large amount of dislocation desities in austenite, but finishing temperature is crossed the low proeutectoid ferrite that may cause and is formed, reduce the intensity of steel plate, 770～860 ℃ of subordinate phase start rolling temperatures of the present invention, finishing temperature is chosen as 750 ℃～800 ℃, has taken into account the influence factor of above-mentioned two aspects.Strain inducing may take place in a large amount of dislocations that make accumulative total in the steel plate that subordinate phase is rolling, separates out trickle carbonitride on dislocation line.Dislocation desity by refine austenite crystal grain and increase austenite inside can promote bainite forming core in the follow-up process of cooling, and refinement is finally organized.
2, process for cooling
By the forced cooling device cooling, steel plate is cooled to 400～520 ℃ with the speed of 8～35 ℃/S to steel plate in rolling back.The steel that adopts composition of the present invention forms bainite with diffusion way usually in process of cooling.Speed of cooling can be bainitic transformation bigger condensate depression and motivating force is provided faster, forms trickle tissue.Lower stop cold temperature steel plate is undergone phase transition at lesser temps, avoid the thick tissue of the higher formation of transformation temperature.The present invention produces the speed of cooling of steel plate and stops cold wider range, but all more than the production yield strength 550MPa and have the steel plate of good low-temperature toughness, has certain superiority in this scope.
In the manufacture method of the present invention, heating and temperature control guarantees the steel plate austenitizing at 1080～1180 ℃, the carbide of Nb and V element is dissolved in the austenite, in the cooling and the operation of rolling, could form tiny precipitate pinning crystal boundary, hinder recrystal grain and grow up the final steel plate tissue of refinement.
1050～1150 ℃ of start rolling temperatures, rolled piece thickness treat that temperature is to 770～860 ℃ during to 2～4 times of finished product thickness.In described temperature open rolling, make steel plate rolling, austenite generation recrystallize, crystal grain thinning in the austenite recrystallization district.The rolled piece gauge control all has enough draught in the fs in the rolling and subordinate phase operation of rolling to guarantee steel plate.Rolling enough draught of fs make fully recrystallize of steel plate, refine austenite crystal grain.The rolling enough draught of subordinate phase make steel plate in the distortion of non-recrystallization district, form a large amount of dislocations in steel plate, and refinement is finally organized.Control treats that Wen Wendu is rolling to guarantee carrying out subordinate phase in suitable temperature, avoid treating that Wen Wendu is too high on the one hand, Recovery Process is violent in the steel plate austenite, dislocation desity descends, avoid on the other hand treating that Wen Wendu is low excessively, template variation in the operation of rolling, and may generate ferrite, reduce armor plate strength.
Deformation rate is 12～28% in the subordinate phase operation of rolling, and finishing temperature is 750～800 ℃.The deformation rate of subordinate phase and finishing temperature are set and are guaranteed that steel plate guarantees the dislocation desity of enrichment in the steel plate on the one hand, guarantees that on the other hand ferrite transformation does not take place steel plate.If the steel plate finishing temperature is low excessively, then may generate ferrite, cause armor plate strength to reduce.
Steel plate is cooled to 420～520 ℃ with 8～35 ℃/s speed, and air cooling after the water outlet, air cooling adopt stacking or cold bed cooling.The steel plate speed of cooling, stop cold temperature and the air cooling mode is set, the composition system that guarantees steel plate can form intensity and low-temperature impact toughness and satisfy requirement of the present invention under this process for cooling condition.Too fast as speed of cooling, it is low excessively to stop cold temperature, then may form martensite, and martensite is crisp phase, reduces the low-temperature impact work of steel plate.If speed of cooling is slow excessively, it is too high to stop cold temperature, then can form thick lath of bainite, ferrite or perlite, and the intensity of steel plate and ballistic work are descended.
The present invention is compared with prior art:
Japanese Patent JP2009221565, JP2008274405, JP2008169467, JP2006283126 and WO2008069289, WO2007119878, WO2007055387 all contains valuable alloying elements cr, Mo, Ni and four kinds of alloying elements of Cu in the composition of WO2000040764 publicity.Contain in Cr, Mo, Ni and the Cu alloying element wherein three kinds of alloying elements in Chinese patent CN101230444, CN101168826, the disclosed composition of CN1786245.Patent WO1999005335, WO1996023909, Chinese patent CN1042950 contains in Cr, Mo, Ni and the Cu alloying element wherein two kinds of alloying elements in the composition of CN1786247 publicity.Contain 0.05～0.5% alloying element cu in the composition of Chinese patent CN1218115 publicity.
Welding crack sensibility index of the present invention is smaller or equal to 0.19%.
Except that the Chinese patent publication number be the Pcm of CN1218115, CN101230444, CN1786427 patent than the present invention low, the Pcm value of all the other patents is all than the present invention height.But contain 0.05～0.5% alloying element cu in the disclosed composition of Chinese patent CN1218115, contain valuable alloying elements cr, Mo and Ni in the disclosed composition of Chinese patent CN10123044, contain Ni and Cu in the disclosed composition of Chinese patent CN1786247, composition system of the present invention all is better than above-mentioned three kinds of patents.
The present invention adopts the composition system that does not contain valuable alloying elements cr, Mo, Ni and Cu, has reduced the cost of alloy that steel plate is produced on the one hand, has improved the welding property of steel plate on the other hand.
Beneficial effect of the present invention:
1. by rational designing chemical composition, substitute valuable Alloy Elements Mo, Ni, Cu etc., reduced alloying element content, reduced the steel plate cost, have lower welding crack sensibility index, need not preheating before the weldering with cheap alloying elements such as Mn.
2. steel plate of the present invention need not carry out any extra modified thermal treatment, thereby has simplified manufacturing process, has reduced the manufacturing cost of steel.
3. because composition and technological design are reasonable, and from implementation result, process system is looser, can in, Plate Steel produces stably manufactured on the line.
4. low welding crack sensitivity steel plate yield strength of the present invention can reach 100mm greater than 550MPa, tensile strength greater than 690MPa, Xia Shi ballistic work Akv (20 ℃) 〉=150J, thickness of slab maximum.Welding crack sensibility indices P cm≤0.19% has good welding property.
Description of drawings
Fig. 1 a is the optical microscope photograph of the microtexture pattern of the embodiment of the invention 3 steel plates;
Fig. 1 b is the field emission scanning electron microscope photo of the microtexture pattern of the embodiment of the invention 3 steel plates.
Embodiment
The invention will be further described below in conjunction with embodiment.
Embodiment 1
Press chemical ingredients electric furnace or the converter smelting shown in the table 1, and be cast into continuously cast bloom, continuous blank heating temperature is 1080 ℃, is incubated 240 minutes; Fs, rolling start rolling temperature was 1050 ℃, and intermediate blank thickness is 80mm; The rolling start rolling temperature of subordinate phase is 860 ℃, and pass deformation rate is 12～25%, and finishing temperature is 800 ℃, and the Finished Steel plate thickness is 20mm; The steel plate speed of cooling is 35 ℃/S, and final temperature is 520 ℃, air cooling after the water outlet.
Embodiment 2
Embodiment is with embodiment 1, and wherein Heating temperature is 1130 ℃, is incubated 150 minutes; Fs, rolling start rolling temperature was 1070 ℃, and intermediate blank thickness is 120mm; The rolling start rolling temperature of subordinate phase is 830 ℃, and pass deformation rate is 15～25%, and finishing temperature is 790 ℃, and the Finished Steel plate thickness is 30mm; The steel plate speed of cooling is 26 ℃/S, and final temperature is 480 ℃, air cooling after the water outlet.
Embodiment 3
Embodiment is with embodiment 1, and wherein Heating temperature is 1130 ℃, is incubated 180 minutes; Fs, rolling start rolling temperature was 1090 ℃, and intermediate blank thickness is 120mm; The rolling start rolling temperature of subordinate phase is 800 ℃, and pass deformation rate is 12～28%, and finishing temperature is 780 ℃, and the Finished Steel plate thickness is 40mm; The steel plate speed of cooling is 20 ℃/S, and final temperature is 460 ℃, air cooling after the water outlet.
Embodiment 4
Embodiment is with embodiment 1, and wherein Heating temperature is 1150 ℃, is incubated 200 minutes; Fs, rolling start rolling temperature was 1100 ℃, and intermediate blank thickness is 150mm; The rolling start rolling temperature of subordinate phase is 790 ℃, and pass deformation rate is 16～24%, and finishing temperature is 770 ℃, and the Finished Steel plate thickness is 50mm; The steel plate speed of cooling is 12 ℃/S, and final temperature is 440 ℃, air cooling after the water outlet.
Embodiment 5
Embodiment is with embodiment 1, and wherein Heating temperature is 1150 ℃, is incubated 220 minutes; Fs, rolling start rolling temperature was 1090 ℃, and rolled piece thickness is 150mm; The rolling start rolling temperature of subordinate phase is 780 ℃, and pass deformation rate is 15～28%, and finishing temperature is 760 ℃, and the Finished Steel plate thickness is 60mm; The steel plate speed of cooling is 10 ℃/S, and final temperature is 420 ℃, air cooling after the water outlet.
Embodiment 6
Embodiment is with embodiment 1, and wherein Heating temperature is 1180 ℃, is incubated 240 minutes; Fs, rolling start rolling temperature was 1120 ℃, and rolled piece thickness is 160mm; The rolling start rolling temperature of subordinate phase is 770 ℃, and pass deformation rate is 18～28%, and finishing temperature is 750 ℃, and the Finished Steel plate thickness is 80mm; The steel plate speed of cooling is 8 ℃/S, and final temperature is 400 ℃, air cooling after the water outlet.
Table 1 embodiment chemical ingredients (wt.%)
| Embodiment | C | Si | Mn | Nb | V | B | Al | Ti | Fe | Pcm ％ |
| 1 | 0.050 | 0.45 | 1.80 | 0.03 | 0.06 | 0.0006 | 0.02 | 0.03 | Surplus | 0.164 |
| 2 | 0.075 | 0.40 | 1.65 | 0.04 | 0.05 | 0.0015 | 0.04 | 0.02 | Surplus | 0.183 |
| 3 | 0.070 | 0.25 | 1.75 | 0.05 | 0.05 | 0.0010 | 0.01 | 0.0010 | Surplus | 0.176 |
| 4 | 0.065 | 0.35 | 1.90 | 0.06 | 0.04 | 0.0018 | 0.03 | 0.0012 | Surplus | 0.182 |
| 5 | 0.080 | 0.40 | 1.65 | 0.05 | 0.07 | 0.0020 | 0.02 | 0.0017 | Surplus | 0.190 |
| 6 | 0.075 | 0.50 | 1.70 | 0.07 | 0.03 | 0.0010 | 0.04 | 0.0020 | Surplus | 0.190 |
Yield strength 550MPa grade low-temp high tenacity low welding crack sensitivity steel plate to embodiment of the invention 1-6 carries out Mechanics Performance Testing, and test result sees Table 2.
The mechanical property of the low welding crack sensitivity steel plate of table 2 embodiment of the invention 1-6
| Embodiment | Thickness of slab mm | Yield strength MPa | Tensile strength MPa | Unit elongation % | -20 ℃ of impact of collision merit J |
| 1 | 20 | 650 | 750 | 19 | 270、258、259 |
| 2 | 30 | 635 | 730 | 18 | 212、228、219 |
| 3 | 40 | 615 | 725 | 18 | 224、218、220 |
| 4 | 50 | 605 | 720 | 19 | 220、210、189 |
| 5 | 60 | 610 | 715 | 17 | 228、197、219 |
| 6 | 80 | 605 | 715 | 18 | 187、212、230 |
From table 1 and table 2 as can be seen, Pcm≤0.19% of the easy welding high toughness thick steel plate that the present invention relates to, yield strength is all greater than 550MPa, and tensile strength is greater than 670MPa, Xia Shi ballistic work Akv (20 ℃) 〉=150J, thickness of slab can reach 80mm.
Low welding crack sensitivity steel plate to the embodiment of the invention 1 carries out welding performance test (little iron grinds test), under the condition of room temperature and 50 ℃, all do not find crackle (seeing Table 3), illustrate that the welding property of steel plate of the present invention is good, generally do not need preheating during welding.
The low welding crack sensitivity steel plate welding performance test result of table 3 embodiment of the invention 1
Embodiment 3 is carried out microtexture research, and optical microscope photograph and field emission scanning electron microscope photo are shown in Fig. 1 a, Fig. 1 b.The microtexture of steel plate is lath of bainite and forms along the carbide of lath interface distributions or horse island difficult to understand.
Claims (6)
1. yield strength 550MPa level is easily welded high strength steel plate, its chemical component weight per-cent is: C0.05～0.08%, Si 0.25～0.50%, Mn 1.65～1.90%, Nb 0.03～0.07%, V0.03～0.07%, B 0.0006～0.002%, Al 0.01～0.04%, Ti 0.01～0.03%, and surplus is Fe and unavoidable impurities; Wherein, the content of Mn should satisfy: 3.31Si+15.8Nb+6.65V-9.12C≤Mn≤4.41Si++13.33Nb+7.72V-7.33C, the yield strength of steel plate greater than 550MPa, tensile strength greater than 670MPa, Xia Shi ballistic work Akv (20 ℃) greater than 150J, welding crack sensibility indices P cm≤0.19%.
2. yield strength 550MPa level as claimed in claim 1 is easily welded the manufacture method of high strength steel plate, comprises smelting, casting, heating, rolling, refrigerating work procedure, it is characterized in that, promptly enters refrigerating work procedure without thermal treatment behind described rolling process; Rollingly be divided into the fs and subordinate phase is rolling, in the described fs operation of rolling, start rolling temperature is 1050～1150 ℃, when rolled piece thickness arrives 2～4 times of Finished Steel plate thickness, treats that on roller-way temperature is to 770～860 ℃; In the described subordinate phase operation of rolling, pass deformation rate is 12～28%, and finishing temperature is 750～800 ℃; In described process of cooling, steel plate is cooled to 400～520 ℃ with the speed of 8～35 ℃/s, air cooling after the water outlet.
3. yield strength 550MPa level as claimed in claim 2 is easily welded the manufacture method of high strength steel plate, it is characterized in that, the continuously cast bloom after the casting or the thickness of steel ingot are not less than 3.5 times of Finished Steel plate thickness.
4. yield strength 550MPa level as claimed in claim 2 is easily welded the manufacture method of high strength steel plate, it is characterized in that, in described heat-processed, Heating temperature is 1080～1180 ℃, and soaking time is 150～240 minutes.
5. yield strength 550MPa level as claimed in claim 2 is easily welded the manufacture method of high strength steel plate, it is characterized in that, air cooling adopts stacking or cold bed cooling.
6. yield strength 550MPa level as claimed in claim 2 is easily welded the manufacture method of high strength steel plate, it is characterized in that, the Finished Steel plate thickness is 15～100mm.
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| CN103255337A (en) * | 2013-04-24 | 2013-08-21 | 河北钢铁股份有限公司邯郸分公司 | Production method of low-cost easily-welded steel |
| CN104004892A (en) * | 2014-06-18 | 2014-08-27 | 济钢集团有限公司 | 70 kg-class TMCP type high-strength steel and method for manufacturing extend rate detection samples thereof |
| CN105543680A (en) * | 2015-12-21 | 2016-05-04 | 秦皇岛首秦金属材料有限公司 | Micro-boron treatment wide and thick plate with tensile strength grade of 700MPa and production method of wide and thick plate |
| CN106521350A (en) * | 2016-11-21 | 2017-03-22 | 河北工业大学 | Preparation method of high-tenacity medium-and-high-carbon superfine bainite steel |
| CN106755869A (en) * | 2016-12-27 | 2017-05-31 | 内蒙古科技大学 | A kind of method that low energy consumption produces Q550D steel plates |
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| CN103114186A (en) * | 2013-03-15 | 2013-05-22 | 济钢集团有限公司 | Control cooling method of easy-welding high-performance steel plate |
| CN103114186B (en) * | 2013-03-15 | 2015-04-08 | 济钢集团有限公司 | Control cooling method of easy-welding high-performance steel plate |
| CN103255337A (en) * | 2013-04-24 | 2013-08-21 | 河北钢铁股份有限公司邯郸分公司 | Production method of low-cost easily-welded steel |
| CN103255337B (en) * | 2013-04-24 | 2014-12-10 | 河北钢铁股份有限公司邯郸分公司 | Production method of low-cost easily-welded steel |
| CN104004892A (en) * | 2014-06-18 | 2014-08-27 | 济钢集团有限公司 | 70 kg-class TMCP type high-strength steel and method for manufacturing extend rate detection samples thereof |
| CN105543680A (en) * | 2015-12-21 | 2016-05-04 | 秦皇岛首秦金属材料有限公司 | Micro-boron treatment wide and thick plate with tensile strength grade of 700MPa and production method of wide and thick plate |
| CN105543680B (en) * | 2015-12-21 | 2018-01-05 | 秦皇岛首秦金属材料有限公司 | Micro- boron processing tensile strength 700MPa levels Wide and Thick Slab and manufacture method |
| CN106521350A (en) * | 2016-11-21 | 2017-03-22 | 河北工业大学 | Preparation method of high-tenacity medium-and-high-carbon superfine bainite steel |
| CN106825578A (en) * | 2016-12-01 | 2017-06-13 | 河池市技术开发中心 | A kind of preparation method of wear-resisting steel plate |
| CN106755869A (en) * | 2016-12-27 | 2017-05-31 | 内蒙古科技大学 | A kind of method that low energy consumption produces Q550D steel plates |
| CN106755869B (en) * | 2016-12-27 | 2018-07-27 | 内蒙古科技大学 | A kind of method of low energy consumption production Q550D steel plates |
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