CN107604248B - A kind of high intensity Q500GJD quenched and tempered state steel plate for building structure and its manufacturing method - Google Patents

Abstract

The present invention relates to a kind of high intensity Q500GJD quenched and tempered state steel plate for building structure, the chemical component of the steel plate is C0.10-0.15%, Si0.20-0.50%, Mn1.10-1.60%, P≤0.015%, S≤0.005%, Cr0.10-0.30%, Mo≤0.30%, Ni+Mo:0.15-0.90%, Cu≤0.30%, Al0.02-0.04%, V0.030-0.080%, Ti0.01-0.02%, V+Nb+Ti≤0.12%, N≤0.006%；The Q500GJD trade mark of its carbon equivalent≤0.52%.This application involves-Q500GJD steel plate for building structure of the condition of delivery for QT (quenched), yield strength 540-580MPa, tensile strength 670-710MPa, elongation >=18%；Yield tensile ratio≤0.82, -20 DEG C of V-type ballistic work >=100J high-strength building steel sheet products.

Description

A kind of high intensity Q500GJD quenched and tempered state steel plate for building structure and its manufacturing method

Technical field

The present invention relates to special steel metallurgical technology field, especially a kind of Q500GJD quenched and tempered state building structure steel plate and its Manufacturing method.

Background technique

The large sizes such as skyscraper, super high-rise building, large span stadiums, airport, conference and exhibition center and steel-structure factory building The structural steel GJ of architectural engineering has strict requirements, is built with being different from existing for the special steel grade of other purposes steel grades It is also especially specific and clearly demarcated to the classification of building structural steel to build industry, the different trades mark has different purposes.

" steel plate for building structure " (the GB/T 19879-2015) that in November, 2016 implements, than GB/T 19879-2005 editions The multiple high-intensitive trade mark such as Q500GJ, Q550GJ etc. are newly increased.This illustrates the steel plate for tall building application of China in recent years It is more and more, in following not far skyscraper, super high-rise building, large span stadiums, airport, conference and exhibition center and steel knot In terms of the large-scale construction engineerings such as structure workshop, only high-intensitive such as 420MPa, 460MPa grades of steel plate for building has been unable to meet and builds Build industry development requirement.The appearance of the standard will be helpful to the building structure for promoting Corporation R & D to be higher than Q460GJ or more the trade mark and use Steel plate.

In the prior art, the Q500 steel plate of correlation intensity can only just have in mechanical equipment steel at present, but mechanical equipment The requirement of building trade is far not achieved again with steel, such asYield tensile ratio, ballistic work, shock resistanceAll it is unable to satisfy building structure use Steel.

The production technology of cut deal is divided by the condition of delivery, mainly there is three kinds of conventional hot rolling, TMCP, heat treatment main works Skill.Currently, the TMCP technique being widely used, compared with conventional hot rolling, due to using controlled rolling and control cooling way, although Production energy consumption increases, but properties of product significantly improve.However, the implementation of TMCP technique, it is necessary to rely on micro alloying element in steel The addition of Nb, V, Ti etc..The microalloy elements resource such as Nb, V, Ti belongs to can not normal regenerated resources.And heat treatment process is mainly led to The control to the distribution of microstructure, form, volume fraction etc. in steel is realized in excess temperature control, and then reaches control steel The purpose of comprehensive performance is heat-treated to guarantee steel performance main means, is hardly dependent on the addition of alloying element.This In the case of, heat treatment is than TMCP technique with more advance；And thermally treated steel performance is uniform, stablizes, Performance Match is good It is good.

A kind of invention " quenched high intensity Q500D super-thick steel plate production method " of notification number CN103556075B is to use 300mm continuous casting billet produces 100-120mm special heavy plate, with slab rolling+Tempering and Quenching.It is large-scale that steel plate is applied to mine, harbour The production of equipment.A kind of invention " production method of quenched high intensity Q500E super-thick steel plate " of notification number CN103556074B is Using slab rolling+Tempering and Quenching production technology, the 100-120mm super-thick steel plate of Q500E is produced, mine, port are also belonged to Mouthful big machinery manufacture steel, it built from Q500 quenched and tempered state height of the invention the difference is that: 1) application field is different.Belong to In mine, harbour big machinery manufacture steel.2) production technology is complicated, and rolling cycle property is long.As " rough rolling step, makes in rolling It is cooling that passage continuously is crossed to slab sky with milling train de-scaling high pressure water ..., at 900-950 DEG C of steel slab surface temperature, opens high pressure per pass Water cools down rolled piece ... ".The cooling mode of this side edging, is unfavorable for the rolling of heavy reduction；And exist inside rolled piece with surface The temperature difference it is larger when, large deformation be also possible to generate rolled piece tissue odds.3) production process is increased.As " press quenching "+from Line quenching.4) low compression ratio: it is only 2.5-3.0 that 300mm continuous casting billet, which produces 100-120mm special heavy plate compression ratio, not can guarantee and obtains Obtain the tissue of respective performances.

The standard of GB/T 19879-2015 is developed new in high intensity Q500GJ series for building structural steel requirement Product simplifies production technology, shortens the production cycle, reduces the Research Emphasis that production cost is those skilled in the art.

Summary of the invention

The new product Q500GJD that the purpose of the present invention is develop in a kind of Q500GJ series of high-intensitive quenched and tempered state, simplifies Production technology shortens the production cycle, reduces production cost, under same requirement, building structure weight is lighter.

The technical solution of the present invention is as follows: a kind of high intensity Q500GJD quenched and tempered state steel plate for building structure, the chemistry of the steel plate Ingredient is C:0.10-0.15%, Si:0.20-0.50%, Mn:1.10-1.60%, P by mass percentage :≤0.015%, S :≤0.005%, Cr:0.10-0.30%, Mo :≤0.30% does not include 0, Ni+Mo:0.15-0.90%, Cu :≤0.30%, The surplus of Al:0.02-0.04%, V:0.030-0.080%, Ti:0.01-0.02%, V+Nb+Ti≤0.12%, N≤0.006% For iron and inevitable impurity element；The Q500GJD trade mark of its carbon equivalent≤0.52%.

This application involves building sheet thickness 12-40mm, the condition of delivery be QT (quenched) Q500GJD building structure use Steel plate, the tissue of steel plate are ferrite+pearlite+a small amount of bainite, 8.0 grades of grain size or more.Its yield strength 540- 580MPa, tensile strength 670-710MPa, elongation >=18%；Yield tensile ratio≤0.82, -20 DEG C of V-type ballistic work >=100J (standards >=47J) high-strength building steel sheet product.Its comprehensive performance is able to satisfy GB/T 19879-2015 and skyscraper completely With the customer requirement of steel plate.

The main function for the smelting ingredient each element that the present invention designs:

C:C element forms the solute element of interstitial solid solution in Fe, and solid solution strengthening effect is greater than other elements in Fe The middle solute element for forming displaced type solid solution.C in the tissue of steel in the form of cementite or pearlite in the presence of can generate very Big phase transformation strengthening, improves intensity.Therefore, the present invention controls the C content in material for 0.10-0.15%.

Mn:Mn element forms the solute element of displaced type solid solution in Fe；Mn mainly has " solid solution strengthening effect, increasing Add and the toughness of steel had a significant impact " etc. number of mechanisms.Therefore, the present invention controls the Mn content in material for 1.1-1.6%.

S: in micro- low-alloy steel, the content of S, which improves, declines the plasticity of steel, toughness；It is therefore preferable that S content to the greatest extent may be used It can be low.

Nb:Nb can prevent crystal grain from growing up when low-alloy steel heats；During the rolling process by strain inducing, it is precipitated Nb's Carbide precipitation prevents ausforming from recrystallizing, reaches refinement crystal grain on crystal boundary and dislocation；Micro- group of steel can be improved It knits, improves performance.

V:V is other than having Nb characteristic of elements, when the compound addition of Nb-V, intensity than individually plus Nb it is high.Austria can also be made Family name's body crystal grain further refines, and keeps ferrite crystal grain after cooling more tiny, is conducive to the improvement of toughness.

Ti: it is to strengthen solid N element.In compound humble steel alloy, N preferentially will form TiN with Ti.TiN prevents heating When AUSTENITE GRAIN COARSENING effect ratio Nb (CN) it is big；The TiN and VN being precipitated using high temperature prevent austenite recrystallization crystal grain thick Change.

Si:Si does not form carbide in steel.But its solid solubility in iron is larger, the significant reinforced ferrite of energy, Gu Molten strengthening effect is higher than Mn.But when Si higher, intensity increases, but toughness declines.Therefore control Si content is 0.20-0.50%.

Cr: it is medium carbide former.The Cr in ferrite is dissolved in, generates solution strengthening, and steel can be improved Harden ability improves the intensity of steel.Therefore, content control is 0.10-0.30%.

Ni: it is non-carbide forming element.It is present in steel with solution, quenching for steel can be improved with the Cr cooperation used time Permeability；The brittle transition temperature for advantageously reducing material simultaneously, improves the impact property of material.

Mo:Mo is present in the solid solution and carbide of steel, there is solution strengthening effect, and the harden ability of steel can be improved.Ni, Mo is somewhat expensive metal, and the present invention controls the sum of Ni, Mo content in material for 0.15-0.90%.

Carbon in the tissue of steel in the form of cementite or pearlite in the presence of can generate very big phase transformation strengthening, improve strong Degree, it is especially more significant to tensile strength contribution, be conducive to the yield tensile ratio of product of the present invention；But it is unfavorable to the toughness of product.Cause This, when Design of Chemical Composition, should consider that product carbon equivalent is restricted, the comprehensive performance requirement cared for again and products thereof；So Carbon element content should not be added excessively high.The higher part in the part or yield tensile ratio that intensity lacks, can pass through and suitable micro- conjunction is added Gold element such as niobium, vanadium, aluminium, nickel etc., and the suitable rolling mill practice of selection；Chemical component and control technique are combined and can be played Precipitation strength, solution strengthening, refinement crystal grain, the inherent tissue for improving steel, reduce the brittle transition temperature of material；Power can be improved again Learn performance.Reach the target for being conducive to that yield tensile ratio is low, impact flexibility is good.

The manufacturing method of above-mentioned high intensity Q500GJD quenched and tempered state steel plate for building structure: raw materials for metallurgy successively uses converter Blow smelting, whole Argon, the deoxidation of LF furnace, desulfurization, the refining for removing folder matter, adjusting component and temperature and RH furnace degassing work in bottom (top) Sequence smelts the molten steel for meeting chemical component requirement；Next production process is as follows

(1) 150mm~370mm blank, continuous casting process major parameter: the degree of superheat 10 are produced using wide thickness plate continuous casting machine ~45 DEG C, 0.5~1.3m/min of casting machine pulling rate；Using dynamic secondary cooling technique, water proportion is 0.5~1.0L/kg；Solidification end is adopted With dynamic soft-reduction, electromagnetic agitation；Charge length is regular by the assembly of change release plate size, by blank scale；Under blank The slow cooling of line heap 24 hours or more；The blank of finishing qualification is sent into mill by production plan；

(2) blank heating: the preheating section temperature of heating furnace: 500-850 DEG C, one Duan Wendu: 900-1100 DEG C of heating, heating Two sections of temperature: 1130-1210 DEG C, soaking section temperature: 1160-1220 DEG C；Heating total time >=10.5 × H minutes, H are that blank is thick Degree, unit: cm, to ensure that blank heating is uniform, blank each section should at the uniform velocity stepping in furnace；

(3) after blank is come out of the stove, removing iron scale is removed using thick descaling mill and pickle line processor；Thick de-scaling includes the water of smart de-scaling Pressure >=20MPa；

(4) rolling divides the two-stage: roughing and finish rolling,

The controlled rolling of roughing: roughing includes the controlled rolling of austenite recrystallization area and austenite Unhydrated cement controlled rolling again, is opened Roll temperature >=980 DEG C, at least 2 passages are in the case where mill capacity allows in roughing passage, using heavy reduction, it is therefore an objective in high temperature When austenite recrystallization area rolls, guarantees that rolling reduction is greater than or equal to 15%, keep austenite grain uniform；In non-recrystallization When area rolls, each percentage pass reduction is bigger, and Zona transformans is more easy to produce, and is easy uniformly in global tissue.To guarantee to obtain The ferrite crystal grain of fine uniform controls total reduction >=40% of austenite Unhydrated cement, to temperature thickness >=60mm；

The controlled rolling of finish rolling: the grain size size of steel after heat treatment is brilliant with the deformed austenite of rolled piece after rolling Based on ferrite grain size after grain and phase transformation.To ensure the deformed austenite crystal grain after controlled rolling and the iron after phase transformation Ferritic crystal grain is grown up, selection after temperature 820-900 DEG C of start rolling temperature, finished product thickness≤12mm can needless to say temperature and Direct Rolling, eventually Rolling temperature is 780-830 DEG C, and three accumulative reduction ratio >=26%, rolls into finished product thickness after finish rolling；

(5) heat rectification machine leveling is sent after the completion of rolling, rolled piece heat rectifys temperature >=500 DEG C；Cold bed natural cooling is sent later；It is cooling To 300-400 DEG C of then offline heap slow cooling, finished product thickness≤12mm not heap slow cooling, heap slow cooling >=300 DEG C, heap slow cooling >=36 are small When；

(6) apparent mass is examined, and on-gauge plate is transferred to heat treatment procedure, and heat treatment uses quenching+tempering, hardening heat 890- 920 DEG C, time inside furnace 1.9-2.4 × H minutes, H was steel plate finished product thickness mm, water cooling；640-680 DEG C of tempering temperature, in furnace Between 3.0-3.5 × H minutes, H be steel plate finished product thickness mm, finished product thickness≤12mm tempering time inside furnace be 15-30 minutes；It is empty It is cooled to room temperature；Flaw detection, steel plate presentation quality are examined, and physicochemical property is examined, shears or cut, is put in storage.

For the steel plate comprehensive performance for obtaining high-intensitive, high tenacity, the application is using controlled rolling and controls cold (TMCP) technique.Controlled rolling Technique is divided into again: the controlled rolling of austenite recrystallization area, the controlled rolling of austenite Unhydrated cement, ferrite and pearlite (A+F) two-phase region Double raisings of intensity and toughness are realized in controlled rolling.In particular, uniformly tiny ferrite crystalline substance is likely to be obtained in Unhydrated cement rolling Grain, it is also possible to obtain the mixed crystal ferrite crystal grain of thickness unevenness.To avoid such unfavorable factor, in the timing of total deformation one, Under mill capacity permissive condition, percentage pass reduction is bigger, and Zona transformans is more easy to produce, and is easier in global tissue It is even.Therefore, it is the iron element alms bowl crystal grain for guaranteeing acquisition fine uniform, needs in Unhydrated cement using heavy reduction, total reduction >=40% is more satisfactory.

According to the GB/T 19879-2015 " steel plate for building structure " that in November, 2016 implements, than GB/T 19879-2005 Version has newly increased the multiple high-intensitive trade mark such as Q500GJ, Q550GJ etc., and current enterprise not yet produces Q500GJD quenched and tempered state in batches Construction(al)steel panel products.The present invention takes the lead in using 150mm-370mm thickness continuous casting billet, heated, two stage rollings, rolling Middle implementation controlled rolling after the completion of rolling, is quenched+tempering heat treatment, produces the Q500GJD construction(al)steel of 12-40mm thickness Plate；Steel plate group is woven to ferrite+pearlite+a small amount of bainite, and 8.0 grades of grain size or more, yield strength 540-580MPa, tension Intensity 670-710MPa, elongation >=18%；Yield tensile ratio≤0.82, -20 DEG C of V-type ballistic work >=100J.

After the application uses quenching-and-tempering process, chemical component can be simplified, reduce the addition type of microalloy element And additive amount, cost of material is reduced, and help to reduce the difficulty of controlled rolling production.Compared with Micro Alloying heat- treated steel, the application Containing a small amount of bainite, make product combination of strength and toughness with higher.

It can reduce building structure weight using this product, reduce the construction cost of building, reduce the steel construction material of building Thickness improves the manufacture reliability of building；

The invention belongs to the products for the production that takes the lead in；The performance of its thickness 12-40mmQ500GJD product is uniform, stablizes, comprehensive It can be good.The current production of enterprise not yet such as this application claims Q500GJD construction(al)steel panel products.

Detailed description of the invention

Fig. 1 is the steel plate metallographic structure figure of the embodiment of the present invention 1.

Specific embodiment

Present invention is further described in detail with reference to embodiments.

Using Jing Guo desulfurization molten iron and high-quality steel scrap as raw material, converter bottom (top) blows smelting, whole Argon, and LF furnace is de- Oxygen, desulfurization, refining and the RH furnace degassing process for removing folder matter, adjusting component and temperature；Finally obtain the weight percent of molten steel To be basic element with Fe and including following elemental composition: C:0.10-0.15%, Si:0.20-0.50%, Mn:1.10- 1.60%, P :≤0.015%, S :≤0.005%, Cr:0.10-0.30%, Mo :≤0.30%, Ni+Mo:0.15-0.90%, Cu :≤0.30%, Al:0.02-0.04%, V:0.030-0.080%, Ti:0.01-0.02%, V+Nb+Ti≤0.12%, N≤ 0.006% surplus is iron and inevitable impurity element；The Q500GJD of its carbon equivalent≤0.52%.

It is raw through wide thickness plate continuous casting machine constant temperature, constant speed and reasonable two cold technique, solidification end dynamic soft-reduction, electromagnetic agitation The continuous casting material of output 150mm-370mm.By the assembly rule of change release plate size, by blank scale；The offline heap of blank Slow cooling 24 hours or more.The blank of finishing qualification is sent into Rolling production by production plan.Heating process: the preheating section of heating furnace Temperature: 500-850 DEG C, two sections of one Duan Wendu: 900-1100 DEG C of heating, heating temperature: 1130-1210 DEG C, soaking section temperature: 1160-1220℃；Heat total time >=10.5 × H minutes (H is sotck thinkness, unit: cm).Heating to ensure blank is equal Even, blank each section should at the uniform velocity stepping in furnace.Blank uses thick descaling mill and pickle line processor except removing iron scale after coming out of the stove；Slightly remove Squama, smart de-scaling hydraulic pressure >=20MPa.

Obtain high-intensitive, high tenacity steel plate comprehensive performance, Ying Caiyong controlled rolling and cold (TMCP) technique of control.Rolling divides second order Section: roughing controlled rolling and finishing rolling control rolling.The controlled rolling of roughing: start rolling temperature >=980 DEG C, in roughing passage at least 2 passages are in the case where mill capacity allows, using heavy reduction；Purpose is to guarantee pressure when high temperature austenite recrystallization zone rolls Amount reaches a certain amount of, i.e., rolling reduction is greater than or equal to 15%, keeps austenite grain uniform.In Unhydrated cement rolling, Each percentage pass reduction is bigger, and Zona transformans is more easy to produce, and is easy uniformly in global tissue.To guarantee to obtain fine uniform Iron element alms bowl crystal grain uses its total reduction >=40% in Unhydrated cement.To temperature thickness >=60mm, (finished product thickness≤12mm is not To temperature).

The controlled rolling of finish rolling: the grain size size of steel after heat treatment is brilliant with the deformed austenite of rolled piece after rolling Based on ferrite grain size after grain and phase transformation.To ensure the deformed austenite crystal grain after controlled rolling and the iron after phase transformation Ferritic crystal grain is grown up, so, (finished product thickness≤12mm is needless to say warm and directly rolls for 820-900 DEG C of start rolling temperature after temperature for selection System), finishing temperature is 780-830 DEG C；Three accumulative reduction ratio >=26% after finish rolling.

Heat rectification machine leveling is sent after the completion of rolling, rolled piece heat rectifys temperature >=500 DEG C；Cold bed natural cooling is sent later；It is cooled to 300-400 DEG C of then offline heap slow cooling (finished product thickness≤12mm not heap slow cooling), heap slow cooling >=300 DEG C, heap slow cooling >=36 hour. Apparent mass is examined, and on-gauge plate is transferred to heat treatment procedure.890-920 DEG C of hardening heat, time inside furnace 1.9-2.4 × H minutes (H-is steel plate finished product thickness, mm), water cooling；640-680 DEG C of tempering temperature, (H-is steel to time inside furnace within 3.0-3.5 × H minutes Board finished product thickness, mm), finished product thickness≤12mm, tempering time inside furnace is 15-30 minutes；It is air-cooled to room temperature.Flaw detection, steel Plate presentation quality is examined, and physicochemical property is examined, shears or cut, is put in storage.

Example 1: using the continuous casting material production rolling 40mm thickness steel plate of 370mm thickness.With continuous casting billet 370 × 2300 × 3200mm, mill product plate 40 × 2600 × L (length) mm.Blank cold charge enters heating furnace, the preheating section temperature of heating furnace: 650- 700 DEG C, two sections of one Duan Wendu: 1000-1050 DEG C of heating, heating temperature: 1150-1200 DEG C, soaking section temperature: 1180-1220 ℃；Heat 220 minutes total times.It is rolled through roughing, to temperature thickness 88mm；820 DEG C of finishing mill start rolling temperature after temperature, through finish rolling Machine rolling, 810 DEG C of finishing temperature；Through heat rectification machine leveling；Cold bed natural cooling is sent later, is cooled to offline heap slow cooling at 335 DEG C； After heap slow cooling in 37 hours, the inspection of steel plate presentation quality is carried out；On-gauge plate is transferred to heat treatment procedure.910 DEG C of hardening heat, in furnace Time 85 minutes, water cooling；670 DEG C of tempering temperature, time inside furnace 136 minutes, it is air-cooled to room temperature.Flaw detection, presentation quality examine and Sampling, physical and chemical inspection.Physicochemical property inspection result is shown in Table 1, metallographic structure (ferrite+pearlite+a small amount of bainite, grain size 8.0 grades or more) such as Fig. 1.

Example 2: design uses the continuous casting material of 150mm thickness, production rolling 20mm thickness steel plate.The continuous casting billet 150 of use × 2400 × 3500mm, mill product plate 12 × 2800 × L (length) mm.Blank cold charge enters heating furnace, the same example of heating process 1.It is rolled down to thickness 65mm through roughing, finishing mill is sent to roll, 795 DEG C of finishing temperature；Rolled piece direct sending enters heat rectification machine after the completion of rolling Leveling；Send cold bed natural cooling；Then finishing, steel plate presentation quality are examined；On-gauge plate is transferred to heat treatment procedure.Hardening heat 905 DEG C, time inside furnace 25 minutes, water cooling；660 DEG C of tempering temperature, time inside furnace 27 minutes, it is air-cooled to room temperature.Flaw detection, appearance matter Amount is examined and sampling, physical and chemical inspection.Physicochemical property inspection result is shown in Table 1.

Service check result table table 1

In addition to the implementation, all to use equivalent transformation or equivalent replacement the invention also includes there is an other embodiments The technical solution that mode is formed should all be fallen within the scope of the hereto appended claims.

Claims (2)

1. a kind of manufacturing method of high intensity Q500GJD quenched and tempered state steel plate for building structure, it is characterised in that: raw materials for metallurgy is successively It is smelted using converter bottom or top blast, whole Argon, the deoxidation of LF furnace, desulfurization, refining and the RH for removing folder matter, adjusting component and temperature Furnace degassing process smelts the molten steel for meeting chemical component requirement；Next production process is as follows

(1) produce 150mm~370mm blank using wide thickness plate continuous casting machine, continuous casting process major parameter: the degree of superheat is 10~45 DEG C, 0.5~1.3m/min of casting machine pulling rate；Using dynamic secondary cooling technique, water proportion is 0.5~1.0L/kg；Solidification end is using dynamic State slighter compress, electromagnetic agitation；Charge length is regular by the assembly of change release plate size, by blank scale；The offline heap of blank Slow cooling 24 hours or more；The blank of finishing qualification is sent into mill by production plan；

(2) blank heating: the preheating section temperature of heating furnace: 500-850 DEG C, one Duan Wendu: 900-1100 DEG C of heating, two sections of heating Temperature: 1130-1210 DEG C, soaking section temperature: 1160-1220 DEG C；Heating total time >=10.5 × H minutes, H is sotck thinkness, Unit: cm, to ensure that blank heating is uniform, blank each section should at the uniform velocity stepping in furnace；

(3) after blank is come out of the stove, removing iron scale is removed using thick descaling mill and pickle line processor；Thick de-scaling include smart de-scaling hydraulic pressure >= 20MPa；

(4) rolling divides the two-stage: roughing and finish rolling,

The controlled rolling of roughing: roughing includes the controlled rolling of austenite recrystallization area and austenite Unhydrated cement controlled rolling, open rolling temperature again >=980 DEG C of degree, at least 2 passages are in the case where mill capacity allows in roughing passage, using heavy reduction, it is therefore an objective in high temperature austenitic When body recrystallization zone rolls, guarantees that rolling reduction is greater than or equal to 15%, keep austenite grain uniform；It is tiny to guarantee to obtain Uniform ferrite crystal grain controls total reduction >=40% of austenite Unhydrated cement, to temperature thickness >=60mm；

The controlled rolling of finish rolling: to ensure that the deformed austenite crystal grain after controlled rolling and the ferrite crystal grain after phase transformation are grown up, Selection 820-900 DEG C of start rolling temperature after temperature, finished product thickness≤12 mm steel plate is needless to say warm and Direct Rolling, finishing temperature are 780-830 DEG C, three accumulative reduction ratio >=26%, rolls into finished product thickness after finish rolling；

(5) heat rectification machine leveling is sent after the completion of rolling, rolled piece heat rectifys temperature >=500 DEG C；Cold bed natural cooling is sent later；It is cooled to 300-400 DEG C of then offline heap slow cooling, finished product thickness≤12 mm not heap slow cooling, heap slow cooling >=300 DEG C, heap slow cooling >=36 hour；

(6) apparent mass is examined, and on-gauge plate is transferred to heat treatment procedure, and heat treatment uses quenching+tempering, hardening heat 890-920 DEG C, time inside furnace 1.9-2.4 × H minutes, H was steel plate finished product thickness mm, water cooling；640-680 DEG C of tempering temperature, time inside furnace 3.0-3.5 × H minutes, H was steel plate finished product thickness mm, and finished product thickness≤12 mm tempering time inside furnace is 15-30 minutes；It is empty It is cooled to room temperature；Flaw detection, steel plate presentation quality are examined, and physicochemical property is examined, shears or cut, is put in storage；

The chemical component of prepared qualified steel sheet product is C:0.10-0.15%, Si:0.20- by mass percentage 0.50%, Mn:1.10-1.60%, P :≤0.015%, S :≤0.005%, Cr:0.10-0.30%, Mo :≤0.30% does not include 0, Ni+ Mo:0.15-0.90%, Cu :≤0.30%, Al:0.02-0.04%, V:0.030-0.080%, Ti:0.01-0.02%, V+ Nb+ Ti The surplus of≤0.12%, N≤0.006% is iron and inevitable impurity element；Its carbon equivalent≤0.52%；The tissue of steel plate is iron Ferritic+pearlite+a small amount of bainite, 8.0 grades of grain size or more.

2. the manufacturing method of high intensity Q500GJD quenched and tempered state steel plate for building structure, feature exist according to claim 1 In: the thickness 12-40mm of product steel plate obtained, the condition of delivery are the Q500GJD steel plate for building structure of QT；It surrenders strong Spend 540-580MPa, tensile strength 670-710MPa, elongation >=18%；Yield tensile ratio≤0.82, -20 DEG C of V-type ballistic work >=100J High-strength building steel sheet product.