CN107604248A - A kind of high intensity Q500GJD quenched and tempered states steel plate for building structure and its manufacture 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 composition 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 trades mark of its carbon equivalent≤0.52%.It is (quenched for QT that the application is related to the condition of delivery）Q500GJD steel plate for building structure, the 580MPa of yield strength 540, the 710MPa of tensile strength 670, elongation >=18%；Yield tensile ratio≤0.82,20 DEG C V-type ballistic work >=100J high-strength building steel sheet product.

Description

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

Technical field

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

Background technology

Skyscraper, high-rise building, large span stadiums, airport, conference and exhibition center and steel-structure factory building etc. are large-scale The structural steel GJ of architectural engineering has strict requirements, and it is to be different from existing for the special steel grade of other purposes steel grades, build It is also especially specific and clearly demarcated to build classification of the industry to building structural steel, the different trades mark has different purposes.

What in November, 2016 implemented《Steel plate for building structure》(GB/T 19879-2015), than GB/T 19879-2005 Version has newly increased multiple the high intensity trade mark such as Q500GJ, Q550GJ etc..This steel plate for tall building of explanation China in recent years should With more and more, in following not far skyscraper, high-rise building, large span stadiums, airport, conference and exhibition center and steel The large-scale construction engineerings such as structure workshop aspect, the only steel plate for building of high intensity such as 420MPa, 460MPa level, can not meet Building trade demand for development.The appearance of the standard will be helpful to the building knot for promoting Corporation R ＆ D to be higher than more than the Q460GJ trades mark Structure steel plate.

In the prior art, the Q500 steel plates of correlation intensity can only just have in plant equipment steel at present, but plant equipment The requirement of building trade is not reached far again with steel, such asYield tensile ratio, ballistic work, shock resistanceIt can not all meet that building structure is used 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.At present, widely used TMCP techniques, compared with conventional hot rolling, due to using controlled rolling and control cooling way, although Energy consumption increase, but properties of product significantly improve.However, the implementation of TMCP techniques, it is necessary to rely on micro alloying element in steel Nb, V, Ti etc. addition.The microalloy element resource such as Nb, V, Ti belongs to can not normal regenerated resources.And Technology for Heating Processing 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 controls steel The purpose of combination property, it is heat-treated to ensure steel performance Main Means, is hardly dependent on the addition of alloying element.This In the case of, it is heat-treated than TMCP technique with more advance；And thermally treated steel performance is uniform, stabilization, Performance Match are good It is good.

A kind of notification number CN103556075B invention " quenched high intensity Q500D super-thick steel plates production method " is to use 300mm continuous casting billets produce 100-120mm special heavy plates, and+Tempering and Quenching is rolled with strand.It is large-scale that steel plate is applied to mine, harbour The production of equipment.A kind of notification number CN103556074B invention " production method of quenched high intensity Q500E super-thick steel plates " is + the production technology of Tempering and Quenching is rolled using strand, Q500E 100-120mm super-thick steel plates is produced, falls within mine, port Mouthful big machinery manufacture steel, the difference that it and Q500 quenched and tempered state height of the invention are built are：1) application field is different.Category In mine, harbour big machinery manufacture steel.2) complex manufacturing, rolling cycle property length.As " rough rolling step, makes in rolling With milling train de-scaling water under high pressure, continuously passage of crossing empty to slab cools down ..., and during 900-950 DEG C of steel slab surface temperature, every time opens high pressure Water cooling rolled piece ... ".The mode of this side edging cooling, is unfavorable for the rolling of heavy reduction；And exist inside rolled piece with surface The temperature difference it is larger when, large deformation is also possible to produce rolled piece tissue odds.3) production process is added.As " press quenching "+from Line quenches.4) low compression ratio：300mm continuous casting billets production 100-120mm special heavy plate compression ratios are only 2.5-3.0, can not ensure to obtain Obtain the tissue of respective performances.

GB/T 19879-2015 standard pin is developed new in high intensity Q500GJ series to building structural steel requirement Product, simplify production technology, shorten the production cycle, reduce the Research Emphasis that production cost is those skilled in the art.

The content of the invention

The purpose of the present invention is the new product Q500GJD developed in a kind of Q500GJ series of high intensity quenched and tempered state, is simplified Production technology, shorten the production cycle, reduce production cost, under equal requirement, building structure weight is lighter.

The technical scheme is that：A kind of high intensity Q500GJD quenched and tempered state steel plate for building structure, the chemistry of the steel plate Composition is C by mass percentage：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% 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≤0.12%, N≤ 0.006% surplus is iron and inevitable impurity element；The Q500GJD trades mark of its carbon equivalent≤0.52%.

The building sheet thickness 12-40mm that the application is related to, the Q500GJD building structure that the condition of delivery is QT (quenched) are used Steel plate, steel plate are organized as ferrite+pearlite+a small amount of bainite, more than 8.0 grades of grain size.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 combination property is entirely capable of meeting GB/T 19879-2015 and skyscraper With the customer requirement of steel plate.

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

C:C element forms the solute element of interstitial solid solution in Fe, and its solid solution strengthening effect is more 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 produce very Big phase transformation strengthening, improves intensity.Therefore, the C content control in material is 0.10-0.15% by the present invention.

Mn:Mn elements form the solute element of displaced type solid solution in Fe；Mn, which mainly has, " solid solution strengthening effect, to be increased Add and the toughness of steel had a significant impact " etc. number of mechanisms.Therefore, the Mn contents control in material is 1.1- by the present invention 1.6%.

S：In micro- low-alloy steel, S content, which improves, will decline the plasticity of steel, toughness；It is therefore preferable that S contents to the greatest extent may be used Can be low.

Nb:Nb can prevent crystal grain from growing up when low-alloy steel heats；By strain inducing in the operation of rolling, Nb is separated out Carbide precipitation on crystal boundary and dislocation, prevent ausforming recrystallize, reach crystal grain thinning；Micro- group of steel can be improved Knit, improve performance.

V：V is in addition to possessing Nb characteristic of elements, during the compound additions of Nb-V, its intensity than individually plus Nb it is high.Austria can also be made Family name's body crystal grain further refines, and makes the ferrite crystal grain after cooling more tiny, is advantageous 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 it is bigger than Nb (CN)；The TiN and VN separated out using high temperature prevents austenite recrystallization crystal grain thick Change.

Si:Si does not form carbide in steel.But its solid solubility in iron is larger, the notable reinforced ferrite of energy, it is solid Molten reinforcing effect is higher than Mn.But when Si is higher, intensity increase, but toughness declines.Therefore it is 0.20-0.50% to control Si contents.

Cr:It is medium carbide former.The Cr dissolved in ferrite, solution strengthening is produced, and steel can be improved Quenching degree, improve the intensity of steel.Therefore, its content control is 0.10-0.30%.

Ni:It is non-carbide former.It is present in solution in steel, coordinates the used time to improve quenching for steel with Cr Permeability；The brittle transition temperature of material is advantageously reduced simultaneously, improves the impact property of material.

Mo:Mo is present in the solid solution and carbide of steel, has solution strengthening effect, and can improve the quenching degree of steel. Ni, Mo are somewhat expensive metals, and Ni, Mo content sum control in material are 0.15-0.90% by the present invention.

Carbon in the tissue of steel in the form of cementite or pearlite in the presence of can produce very big phase transformation strengthening, improve strong Degree, it is especially more notable to tensile strength contribution, be advantageous to the yield tensile ratio of product of the present invention；It is but unfavorable to the toughness of product.Cause This, during Design of Chemical Composition, should consider that product carbon equivalent is restricted, the combination property requirement cared for again and products thereof；So Carbon element content should not add too high.The part of intensity missing, or the part that yield tensile ratio is higher, can be by adding appropriate micro- conjunction Gold element such as niobium, vanadium, aluminium, nickel etc., and the suitable rolling mill practice of selection；Chemical composition and control technique are combined and can played Precipitation strength, solution strengthening, crystal grain thinning, the inherent tissue for improving steel, reduce the brittle transition temperature of material；And can improves power Learn performance.Reach the target for being advantageous to that yield tensile ratio is low, impact flexibility is good.

The manufacture method of above-mentioned high intensity Q500GJD quenched and tempered state steel plate for building structure：Raw materials for metallurgy uses converter successively Smelting is blown at bottom (top), whole Argon, the deoxidation of LF stoves, desulfurization, removes folder matter, adjusting component and the refining of temperature and the degassing of RH stoves Process smelts the molten steel for meeting chemical composition requirement；Ensuing production process is as follows

(1) using wide thickness plate continuous casting machine production 150mm~370mm blanks, its 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 adopted With dynamic soft-reduction, electromagnetic agitation；Charge length is regular by the assembly of change release plate size, by blank scale；Under blank Line heap slow cooling more than 24 hours；The qualified blank of finishing is sent into mill by the production schedule；

(2) blank heating：The preheating section temperature of heating furnace：One section of 500-850 DEG C, heating temperature：900-1100 DEG C, heating Two sections of temperature：1130-1210 DEG C, soaking zone temperature：1160-1220℃；Total time >=10.5 × H minutes are heated, H is blank Thickness, unit：Cm, to ensure that blank heating is uniform, blank each section should at the uniform velocity stepping in stove；

(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, opens 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, ensure that rolling reduction is more than or equal to 15%, make austenite crystal uniform；In non-recrystallization When area rolls, each percentage pass reduction is bigger, the easier generation of Zona transformans, and easily uniform in global tissue.To ensure to obtain The ferrite crystal grain of fine uniform, total reduction >=40% of austenite Unhydrated cement is controlled, treats temperature thickness >=60mm；

The controlled rolling of finish rolling：The grain size size of steel after heat treatment, it is brilliant with the deformed austenite of rolled piece after rolling Based on ferrite grain size after grain and phase transformation.To ensure the iron after deformed austenite crystal grain and phase transformation after controlled rolling 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 Temperature is rolled for 780-830 DEG C, and three accumulative reduction ratio >=26%, rolls into finished product thickness after finish rolling；

(5) heat rectification machine leveling, strong temperature >=500 DEG C of rolled piece heat are sent after the completion of rolling；Cold bed natural cooling is sent afterwards；Cooling It is small 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, its heap slow cooling >=36 When；

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

To obtain high intensity, the steel plate combination property of 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 Controlled rolling, realize double raisings of intensity and toughness.In particular, uniformly tiny ferrite crystalline substance is likely to be obtained in Unhydrated cement rolling Grain, it is also possible to obtain the uneven mixed crystal ferrite crystal grain of thickness.To avoid such a unfavorable factor, in total deformation one regularly, Under mill capacity permissive condition, percentage pass reduction is bigger, the easier generation of Zona transformans, and is easier in global tissue It is even.Therefore, the iron element alms bowl crystal grain of fine uniform is obtained, it is necessary to use heavy reduction, total reduction in Unhydrated cement for guarantee >=40% is more satisfactory.

The GB/T 19879-2015 implemented according in November, 2016《Steel plate for building structure》, than GB/T 19879-2005 Version has newly increased multiple the high intensity trade mark such as Q500GJ, Q550GJ etc., currently also quenched without enterprise batch production Q500GJD The construction(al)steel panel products of state.The present invention takes the lead in using 150mm-370mm thickness continuous casting billets, heated, two stage rollings, rolls Controlled rolling is carried out in system, after the completion of rolling, quenched+tempering heat treatment, produce 12-40mm thickness Q500GJD it is for building Steel plate；Steel plate is organized as ferrite+pearlite+a small amount of bainite, more than 8.0 grades, yield strength 540-580MPa of grain size, resists Tensile strength 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 composition can be simplified, reduce the addition species of microalloy element And addition, 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 that there is higher combination of strength and toughness.

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

The invention belongs to the product for the production that takes the lead in；The performance of its thickness 12-40mmQ500GJD products is uniformly, stably, comprehensive Can be good.Currently also without enterprise produce such as this application claims Q500GJD construction(al)steel panel products.

Brief description of the drawings

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

Embodiment

The present invention is described in further detail with reference to embodiments.

Smelting, whole Argon, LF stoves are blown as raw material, converter bottom (top) using the molten iron Jing Guo desulfurization and high-quality steel scrap Deoxidation, desulfurization, refining and the RH stove degassing process for removing folder matter, adjusting component and temperature；Finally give the weight percent of molten steel Than for the element based on 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%.

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

High intensity, the steel plate combination property of high tenacity are obtained, controlled rolling should be used and control cold (TMCP) technique.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 when being rolled in high temperature austenite recrystallization zone, ensures pressure Amount reaches a certain amount of, i.e., rolling reduction is more than or equal to 15%, makes austenite crystal uniform.When Unhydrated cement rolls, Each percentage pass reduction is bigger, the easier generation of Zona transformans, and easily uniform in global tissue.To ensure to obtain fine uniform Iron element alms bowl crystal grain, its total reduction >=40% is employed in Unhydrated cement.Treat temperature thickness >=60mm (finished product thicknesses≤12mm It is needless to say warm).

The controlled rolling of finish rolling：The grain size size of steel after heat treatment, it is brilliant with the deformed austenite of rolled piece after rolling Based on ferrite grain size after grain and phase transformation.To ensure the iron after deformed austenite crystal grain and phase transformation after controlled rolling 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, strong temperature >=500 DEG C of rolled piece heat are sent after the completion of rolling；Cold bed natural cooling is sent afterwards；It is cooled to 300-400 DEG C then offline heap slow cooling (finished product thickness≤12mm not heap slow cooling), heap slow cooling >=300 DEG C, its heap slow cooling >=36 are small When.Apparent mass is examined, and on-gauge plate is transferred to heat treatment step.890-920 DEG C of hardening heat, 1.9-2.4 × H points of time inside furnace Clock (H-be steel plate finished product thickness, mm), water cooling；640-680 DEG C of temperature, time inside furnace 3.0-3.5 × H minutes (H-be Steel plate 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, storage.

Example 1：Using the thick continuous casting material production rolling 40mm thickness steel plates of 370mm.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- One section of 700 DEG C, heating temperature：Two sections of 1000-1050 DEG C, heating temperature：1150-1200 DEG C, soaking zone temperature：1180-1220 ℃；Heat 220 minutes total times.Rolled through roughing, treat temperature thickness 88mm；820 DEG C of finishing mill start rolling temperature after temperature, through finish rolling Machine rolls, 810 DEG C of finishing temperature；Through heat rectification machine leveling；Cold bed natural cooling is sent afterwards, is cooled to offline heap slow cooling at 335 DEG C； After heap slow cooling in 37 hours, steel plate presentation quality inspection is carried out；On-gauge plate is transferred to heat treatment step.910 DEG C of hardening heat, in stove 85 minutes time, water cooling；670 DEG C of temperature, time inside furnace 136 minutes, is air-cooled to room temperature.Flaw detection, presentation quality examine and Sampling, physical and chemical inspection.Physicochemical property assay is shown in Table 1, metallographic structure (ferrite+pearlite+a small amount of bainite, grain size 8.0 it is more than level) such as Fig. 1.

Example 2：Design is using continuous casting material thick 150mm, production rolling 20mm thickness steel plates.The continuous casting billet 150 of use × 2400 × 3500mm, mill product plate 12 × 2800 × L (length) mm.Blank cold charge enters heating furnace, heats the same example of technique 1.Thickness 65mm is rolled down to through roughing, send finishing mill 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 step.Hardening heat 905 DEG C, time inside furnace 25 minutes, water cooling；660 DEG C of temperature, time inside furnace 27 minutes, is air-cooled to room temperature.Flaw detection, outward appearance matter Amount is examined and sampling, physical and chemical inspection.Physicochemical property assay is shown in Table 1.

Service check result table table 1

In addition to the implementation, it is all to use equivalent transformation or equivalent replacement present invention additionally comprises there is other embodiment The technical scheme that mode is formed, it all should fall within the scope of the hereto appended claims.

Claims (4)

1. A kind of 1. high intensity Q500GJD quenched and tempered state steel plate for building structure, it is characterised in that：The chemical composition of the steel plate presses quality Percentages are 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% does not include 0, Ni+Mo：0.15-0.90%, Cu：≤ 0.30%, Al：0.02-0.04%, V： 0.030-0.080%, Ti：The surplus of 0.01-0.02%, V+ Nb+ Ti≤0.12%, N≤0.006% is iron and inevitably miscellaneous Prime element；The Q500GJD trades mark of its carbon equivalent≤0.52%.
2. 2. high intensity Q500GJD quenched and tempered state steel plate for building structure according to claim 1, it is characterised in that：Steel plate is thick 12-40mm is spent, the condition of delivery is that QT is (quenched）Q500GJD steel plate for building structure；Its yield strength 540-580MPa, tension Intensity 670-710MPa, elongation >=18%；Yield tensile ratio≤0.82, -20 DEG C of V-type ballistic work >=100J high-strength building steel Panel products.
3. 3. high intensity Q500GJD quenched and tempered state steel plate for building structure according to claim 1, it is characterised in that：Ferrite+ Pearlite+a small amount of bainite, more than 8.0 grades of grain size.
4. 4. the method for high intensity Q500GJD quenched and tempered state steel plate for building structure, its feature exist described in a kind of manufacturing claims 1 In：Raw materials for metallurgy uses converter bottom successively（Top）Smelting is blown, whole Argon, the deoxidation of LF stoves, desulfurization, removes folder matter, adjusting component And the refining of temperature and RH stoves degassing process smelt the molten steel for meeting chemical composition requirement；Ensuing production process is as follows

   （1）150mm~370mm blanks, its continuous casting process major parameter are produced using wide thickness plate continuous casting machine：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；End is solidified 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 more than 24 hours；The qualified blank of finishing is sent into mill by the production schedule；

   （2）Blank heating：The preheating section temperature of heating furnace：One section of 500-850 DEG C, heating temperature：900-1100 DEG C, two sections of heating Temperature：1130-1210 DEG C, soaking zone temperature：1160-1220℃；Total time >=10.5 × H minutes are heated, H is sotck thinkness, Unit：Cm, to ensure that blank heating is uniform, blank each section should at the uniform velocity stepping in stove；

   （3）After blank is come out of the stove, removing iron scale is removed using thick descaling mill and pickle line processor；Thick hydraulic pressure of the de-scaling including smart de-scaling >= 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, ensure that rolling reduction is more than or equal to 15%, make austenite crystal uniform；It is tiny to ensure to obtain Uniform ferrite crystal grain, total reduction >=40% of austenite Unhydrated cement is controlled, treats temperature thickness >=60mm；

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

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

   （6）Apparent mass is examined, and on-gauge plate is transferred to heat treatment step, and heat treatment uses quenching+tempering, hardening heat 890-920 DEG C, time inside furnace 1.9-2.4 × H minutes, H is steel plate finished product thickness mm, water cooling；640-680 DEG C of temperature, time inside furnace 3.0-3.5 × H minutes, H are steel plate finished product thickness mm, and the mm of finished product thickness≤12 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, storage.