CN105734236B - The method for improving think gauge pipeline steel block hammer performance - Google Patents

The method for improving think gauge pipeline steel block hammer performance Download PDF

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CN105734236B
CN105734236B CN201610150744.0A CN201610150744A CN105734236B CN 105734236 B CN105734236 B CN 105734236B CN 201610150744 A CN201610150744 A CN 201610150744A CN 105734236 B CN105734236 B CN 105734236B
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steel
think gauge
pipe line
roughing
temperature
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CN105734236A (en
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熊雪刚
张开华
叶晓瑜
周伟
李卫平
王羿
龚慧
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Pangang Group Panzhihua Iron and Steel Research Institute Co Ltd
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Pangang Group Panzhihua Iron and Steel Research Institute Co Ltd
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    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21DMODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0221Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
    • C21D8/0226Hot rolling
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21DMODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D2211/00Microstructure comprising significant phases
    • C21D2211/005Ferrite
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21DMODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D2211/00Microstructure comprising significant phases
    • C21D2211/009Pearlite

Abstract

The present invention relates to the method for improving think gauge pipeline steel block hammer performance, belong to hot continuous-milling steel plate technical field.Present invention solves the technical problem that being to provide the method for improving think gauge pipeline steel block hammer performance, by using the big soft reduction process of low temperature, rolling temperature is reduced, improve rolling reduction ratio, increase section cooling speed, so as to obtain ultra-fine ferrite crystal grain, improve the block hammer performance of think gauge pipe line steel.By the inventive method, section of shear ratio that the DWTT of think gauge pipe line steel can drop hammer brings up to 97%.

Description

The method for improving think gauge pipeline steel block hammer performance
Technical field
The present invention relates to the method for improving think gauge pipeline steel block hammer performance, belong to hot continuous-milling steel plate technical field.
Background technology
Drop weight tearing performance is the important indicator that oil-gas pipeline steel series of products toughness is judged, and is mainly used in preventing oil gas Pipeline occurs accident and causes serious consequence suddenly due to brittle break in use.The shadow of pipeline steel block hammer tear resistance The factor of sound is numerous, and it is brilliant mainly to include strand degree of segregation, field trash, Carbide Precipitation, organization type, structural homogenity, ferrite The factors such as granularity.Drop weight tearing performance characterization be material suppression Crack Extension ability, the banded structure formed in steel, folder The presence of debris can accelerate Crack Extension, reduce block hammer performance.Material structure is uneven, or is also difficult to suppress when grain size is thick Crack Extension, block hammer performance can be caused unqualified.
The block hammer performance control of more than 14mm think gauge hot continuous rolling pipeline steels is a big technological difficulties.Pipe line steel thickness is got over Thickness, in order to ensure its intensity requirement, it is necessary to cooling velocity and lower coiling temperature, but cooling velocity is faster, batches faster Temperature is lower, and the temperature homogeneity of coil of strip section is poorer, and structural homogenity is poorer, causes low temperature fracture toughness to be particularly dropping hammer property Can be poorer.
Therefore, to improve the block hammer performance of think gauge pipe line steel, rational smelting process and rolling mill practice should be formulated.
CN103388110A discloses a kind of method improved compared with think gauge X60 pipeline steel block hammer performances, strictly controls steel Chemical composition, using 250mm blanks produce 22~26mm compared with think gauge X60 pipe line steels.Control roughing speed 1.5~ 2.5m/s, 1000~1100 DEG C of temperature, the reduction ratio of rear 3 passage are all higher than 15%, roughing total deformation rate >=60%, and middle base is thick Spend for 70~90mm;It is 3~3.5 to control finish rolling compression ratio, and continuous 3 percentage pass reductions are more than 15%, and finish rolling total deformation rate is 60~75%, 880~920 DEG C of start rolling temperature, 760~800 DEG C of finishing temperature, final cooling temperature control is at 500~560 DEG C, cooling Speed is 11~20 DEG C/s.The low temperature block hammer performance of pipe line steel is improved using described process conditions, the synthesis of product is qualified Rate has brought up to more than 90%.But the pipe line steel need to strictly control the composition of steel, complex process, undoubtedly improve the life of steel Produce cost.
CN103937950A discloses a kind of production technology of low compression ratio think gauge pipe line steel.Main component is:C: 0.03~0.08%, Si:0.15~0.35%, Mn:1.50~2.00%, Ni≤0.30%, Cr≤0.030%, Nb:0.05~ 0.09%, Mo≤0.25%, the hot rolling technology used for:1100~1220 DEG C of slab heating temperature, roughing percentage pass reduction >= 15%, 80~120mm of workpiece thickness, 780~850 DEG C of entrance finishing temperature, 740~800 DEG C of finish rolling end temp, cooling speed Spend 15~25 DEG C/s, 100~400 DEG C of final cooling temperature.Described pipe line steel grade of steel is X80, and metallographic structure is acicular ferrite.Should Pipe line steel is high-grade pipe line steel, and using acicular ferrite route, different from low level pipe line steel, high-grade pipe line steel is due to pin Columnar ferrite phase transition temperature is relatively low, is also not in abnormal structure during using relatively low final cooling temperature, influences low temperature block hammer performance. Therefore, the production method of high-grade pipe line steel is not particularly suited for the pipe line steel of low level.
CN104109744A discloses a kind of method for improving pipeline steel block hammer performance.This method includes heating steel billet, rolled Step is made and batches, wherein:A, heating steel billet:By heating steel billet to 1160~1220 DEG C;B, roll:Steel billet after heating is entered Row roughing obtains middle base, then middle base is carried out into finish rolling;Wherein, every time deflection >=20% of roughing step;Finish rolling step Middle inlet temperature is 960~1000 DEG C, and finishing temperature is Ar3+ (0~50) DEG C;C, batch:Rolled up at 580~630 DEG C Take.This method is not on the premise of original pipeline composition of steel is changed, and by optimize technique, improves the even tissue of whole section Property, so as to improve block hammer performance, suitable for low level pipe line steel, it is poor that its ferrite+pearlite type structural homogenity can be improved The problems such as.But this method is more than 8mm suitable for thickness, below 14mm pipe line steel, for more than 14mm pipe line steel, Using this method, the block hammer performance of pipe line steel needs further to be improved.This method coiling temperature can not drop too low, otherwise easily The abnormal structures such as bainite, martensite are produced, influence the low temperature block hammer performance of steel plate.
The content of the invention
Present invention solves the technical problem that it is to provide the method for improving think gauge pipeline steel block hammer performance, for improving 14mm The pipeline steel block hammer performance of above thickness.
The present invention improve think gauge pipeline steel block hammer performance method, steel billet is heated successively, roughing, finish rolling, layer Stream is cooled down and batched, and obtains think gauge pipe line steel finished product, wherein, the heating-up temperature is 1150~1179 DEG C;Roughing is using extremely Few 5 passes, each pass deformation >=20%, wherein rear 2 pass deformation >=30%, roughing end pass speed 2.0~ 2.5mm/s;Start rolling temperature≤949 DEG C of finish rolling, finishing temperature are 730~780 DEG C;After finish rolling terminates, first with 41~80 DEG C/s Cooling velocity be cooled to 520~590 DEG C, 2~8s of air cooling, be then cooled to 500~579 with 15~25 DEG C/s cooling velocity DEG C batched.
Further, the thickness of the think gauge pipe line steel finished product is more than 14mm, preferably think gauge pipe line steel finished product Thickness be 14~18mm.
Further, 200~250mm of steel billet thickness, the workpiece thickness after roughing are 56~58mm.
Further, roughing uses 5~7 passes, and at least opens 4 passage dephosphorization water.
Wherein, the think gauge pipe line steel preferably consists of the following components in percentage by weight:C:0.03~0.07%, Si:0.10~0.35%, Mn:0.80~1.60%, Nb≤0.05%, 0 < Cr≤0.30%, V≤0.05%, remaining be Fe and Inevitable impurity.
Further, the microscopic structure of the think gauge pipe line steel is preferably ultra-fine ferrite and pearlitic structrure, and it is brilliant Granularity is more than 12 grades.
In the present invention, the pipe line steel grade of steel is preferably X60 and following rank, and more preferably pipe line steel grade of steel is X42, X52 Or X60.
Think gauge pipe line steel of the present invention, using inexpensive ferrite+pearlitic structrure route, to ensure dropping hammer property of low temperature Steel plate center portion intensity of cooling can be increased, it is necessary to reduce final cooling temperature, but bainite, horse easily occur when final cooling temperature is too low Shi Tideng abnormal structures, or cause surface and core structure uneven etc..Therefore, the present invention is by using the big pressure work of low temperature Skill, rolling temperature is reduced, improve rolling reduction ratio, increase section cooling speed, so as to obtain ultra-fine ferrite crystal grain, improved thick The block hammer performance of specification pipe line steel.By the inventive method, the section of shear that the DWTT of think gauge pipe line steel can drop hammer is than improving To 97%.
Compared with prior art, the present invention has the advantages that:
1st, described think gauge pipe line steel uses the alloy system of lower cost, it might even be possible to it is micro- not add Nb, V, Mo etc. Alloying element, by optimizing cooling controlling and rolling controlling process, make described pipe line steel that there is fine grain ferritic structure, so as to ensure that it falls Hammer tear resistance into shape.
2nd, described think gauge pipe line steel uses the big soft reduction process of low temperature, by reducing rolling temperature, improving rolling deformation Amount, increase section cooling speed, obtain ultra-fine grained ferrite, make described pipe line steel while have good strength character and excellent Different drop weight tearing performance.
Embodiment
The present invention improve think gauge pipeline steel block hammer performance method, steel billet is heated successively, roughing, finish rolling, layer Stream is cooled down and batched, and obtains think gauge pipe line steel finished product, wherein, the heating-up temperature is 1150~1179 DEG C;Roughing is using extremely Few 5 passes, each pass deformation >=20%, wherein rear 2 pass deformation >=30%, roughing end pass speed 2.0~ 2.5mm/s;Start rolling temperature≤949 DEG C of finish rolling, finishing temperature are 730~780 DEG C;After finish rolling terminates, first with 41~80 DEG C/s Cooling velocity be cooled to 520~590 DEG C, 2~8s of air cooling, be then cooled to 500~579 with 15~25 DEG C/s cooling velocity DEG C batched.
The method that the present invention improves think gauge pipeline steel block hammer performance, billet heating temperature are controlled at 1150~1179 DEG C, Austenite abnormal growth in heating process so can have both been avoided, in turn ensure that the solid solution of microalloy element.
Preferably, roughing uses 5~7 passes, every time deflection >=20%, wherein after 2 pass deformations >= 30%, 4 passage dephosphorization water, roughing end 2.0~2.5mm/s of pass speed are at least opened in roughing;So ensure rough rolling process compared with Carried out under low temperature conditions, reduce roughing speed, increase roughing pass deformation, ensure austenite recrystallization and austenite crystal Refinement.
Further, the thickness of the think gauge pipe line steel finished product is more than 14mm, preferably think gauge pipe line steel finished product Thickness is 14~18mm.
Steel billet 200~250mm of thickness, the workpiece thickness after roughing are 56~58mm.Finished product thickness is different, after roughing in Between base thickness it is also different.During finished product thickness increase, increase workpiece thickness, the non-recrystallization zone deformation of finishing stands can be increased Amount, fining ferrite grains.
Further, preferably, finish rolling start rolling temperature≤949 DEG C, finishing pass deflection is increased.This ensure that Finish rolling start rolling temperature increases the pass deformation of finish rolling, tired out so as to add non-recrystallization zone close to critical recrystallization temperature Product deflection, increases ferrite forming core core, fining ferrite grains.
Finishing stands start section cooling after terminating, be first cooled to 520~590 DEG C with 41~80 DEG C/s cooling velocity, 2~8s of air cooling, then it is cooled to 500~580 DEG C with 15~25 DEG C/s cooling velocity and is batched.Using segmentation section cooling Mode, first using quick section cooling, keep the austenite after deformation constant until dynamic phase trasnsition point, so improve supercooling Degree, makes the driving force of forming core during phase transformation increase, so as to improve nucleation rate, fining ferrite grains.And by with controlled rolling phase With reference to the drafts of a few frame finishing mills (such as F5-F7), utilizes deformation induced trans- formation and ferrite after reducing rolling temperature and improving Dynamic recrystallization principle, increase ferritic forming core point, the effect to crystal grain thinning will be apparent from.Research shows, cools down Speed forms nonequiaxial ferrite+pearlitic structrure in 30~40 DEG C/more than s, and ferrite spiculation trend is obvious, and Crystal grain is tiny, by build up and dislocation strengthening, so as to ensure that material has excellent mechanical property.
Further, think gauge pipe line steel of the present invention consists of the following components in percentage by weight:C:0.03~ 0.07%, Si:0.10~0.35%, Mn:0.80~1.60%, Nb≤0.05%, 0 < Cr≤0.30%, V≤0.05%, its Remaining is Fe and inevitable impurity.
In the present invention, C content is relatively low, is due to pipe line steel to inclusion behavior, banded structure, low-temperature flexibility and weldability It can require strict, therefore by C content control 0.03~0.07%, and the low structural homogenity to think gauge pipe line steel of C content Favorably, when this is due to that C content is low, center portion is not easy martensite, shellfish occur when reducing final cooling temperature, increase section cooling intensity Shi Tideng abnormal structures;Cr main function is to improve anti-cold quenching ability, increases the cooling uniformity on steel plate center portion and surface, changes The structural homogenity in mercy portion, finished product thickness is 14~18mm, by controlling C content, and adds the Cr of content≤0.30%, really Protecting described pipe line steel has excellent anti-cold quenching ability;Nb main function is to strengthen fine grain, reduce recrystallization temperature so that Pipe line steel can roll under relatively low final rolling temperature, increase not in the cumulative deformation of crystal region, refine final ferrite Crystal grain, improve block hammer performance;V mainly plays solution strengthening.
The microscopic structure of the think gauge pipe line steel is preferably ultra-fine ferrite and pearlitic structrure, and its grain size is 12 grades More than.
The grade of steel of the pipe line steel is preferably X60 and following rank, including X42, X52, X60 etc., finished product thickness be 14~ 18mm。
Think gauge pipe line steel of the present invention, using inexpensive ferrite+pearlitic structrure route, to ensure dropping hammer property of low temperature Steel plate center portion intensity of cooling can be increased, it is necessary to reduce final cooling temperature, but bainite, horse easily occur when final cooling temperature is too low Shi Tideng abnormal structures, or cause surface and core structure uneven etc..Therefore, the present invention is by using the big pressure work of low temperature Skill, rolling temperature is reduced, improve rolling reduction ratio, increase section cooling speed, so as to obtain ultra-fine ferrite crystal grain, improved thick The block hammer performance of specification pipe line steel.By the inventive method, the section of shear that the DWTT of think gauge pipe line steel can drop hammer is than improving To 97%.
The embodiment of the present invention is further described with reference to embodiment, therefore not limited the present invention System is among described scope of embodiments.
The pipe line steel technological process of production in embodiment is:Desulfurizing iron → converter smelting top-bottom blowing → deoxidation, alloy After change → stove chain-wales mend feed Al lines → LF refining heating → continuous casting → heating of plate blank → high-pressure water descaling → roughing → finish rolling → Section cooling → batch → packaging and storage.
Embodiment 1
X60 pipe line steels thick 14mm, using Nb-V microalloying routes, pre-processed by molten iron, converter smelting, LF heating Stove refining, continuous casting obtain steel billet, and specific chemical composition percentage by weight is:0.06C-0.21Si-1.49Mn-0.035Nb- 0.04V-0.23Cr;Steel billet relation reheating temperature is 1172 DEG C, and roughing uses 5 passes, and each percentage pass reduction is 20%, 20%, 22%, 30%.30%, 4 passage dephosphorization water are opened in roughing, and roughing extreme trace time mill speed is 2.5m/s, and workpiece thickness is 56mm;Finish rolling is 7 frame hot continuous rollings, and each percentage pass reduction is respectively 38%, 36%, 0,26%, 0,12%, 10%, and finish rolling is opened Beginning temperature is 946 DEG C, and finishing temperature is 776 DEG C;After finish rolling terminates, 535 DEG C are cooled to 45 DEG C/s cooling velocity, air cooling 5s, then it is cooled to 500 DEG C with 16 DEG C/s cooling velocity and batches.
After testing, the X60 pipeline steel mechanical properties that the present embodiment is produced are:Rt0.5:465MPa, Rm:572MPa, A: 40.5%, Rt0.5/Rm:0.81, -20 DEG C of Charpy-V impact powers:329.9J, -20 DEG C of DWTT drop hammer section of shear ratio:Monodrome is 98%, 98%, average 98%.Metallographic structure is ferrite+pearlite, and grain size is 13.5 grades.
Embodiment 2
X42 pipe line steels thick 16mm, using C-Mn steel into shunt lead, addition Cr increases anti-cold quenching ability, by molten iron Pretreatment, converter smelting, the refining of LF heating furnaces, continuous casting obtain steel billet, and the percentage by weight of specific chemical composition is:0.06C- 0.14Si-0.98Mn-0.18Cr;Steel billet relation reheating temperature is 1176 DEG C, and roughing uses 5 passes, and each percentage pass reduction is 20%, 20%, 22%, 30%.30%, 4 passage dephosphorization water are opened in roughing, and roughing extreme trace time mill speed is 2.5m/s, middle base Thickness is 57mm;Finish rolling is 7 frame hot continuous rollings, and each percentage pass reduction is respectively 34%, 32%, 0,22%, 0,11%, 11%, Entrance finishing temperature is 945 DEG C, and finishing temperature is 778 DEG C;After finish rolling terminates, 530 DEG C are cooled to 50 DEG C/s cooling velocity, Air cooling 5s, then it is cooled to 500 DEG C with 16 DEG C/s cooling velocity and batches.
After testing, the X42 pipeline steel mechanical properties that the present embodiment is produced are:Rt0.5:355MPa, Rm:445MPa, A: 49%, Rt0.5/Rm:0.79, -10 DEG C of Charpy-V impact powers:264.1J, -10 DEG C of DWTT drop hammer section of shear ratio:Monodrome is 97%, 97%, average 97%.Metallographic structure is ferrite+pearlite, and grain size is 13.5 grades.
Embodiment 3
X52 pipe line steels thick 16mm, using Nb microalloying routes, are pre-processed, converter smelting, LF heating furnaces by molten iron Refining, continuous casting obtain steel billet, and specific chemical composition percentage by weight is:0.05C-0.16Si-1.18Mn-0.030Nb;Steel billet is again Heating-up temperature is 1169 DEG C, and roughing uses 5 passes, and each percentage pass reduction is 20%, 20%, 22%, 31%, 31%, slightly 4 passage dephosphorization water are rolled out, roughing extreme trace time mill speed is 2.0m/s, workpiece thickness 56mm;Finish rolling is that 7 frames heat connects Roll, each percentage pass reduction is respectively 35%, 31%, 0,21%, 0,12%, 10%, and entrance finishing temperature is 949 DEG C, finish to gauge temperature Spend for 775 DEG C;After finish rolling terminates, 540 DEG C are cooled to 50 DEG C/s cooling velocity, air cooling 5, then with 15 DEG C/s cooling speed Degree is cooled to 510 DEG C and batched.
After testing, the X52 pipeline steel mechanical properties that the present embodiment is produced are:Rt0.5:405MPa, Rm:488MPa, A: 44.5%, Rt0.5/Rm:0.83, -20 DEG C of Charpy-V impact powers:251.3J, -20 DEG C of DWTT drop hammer section of shear ratio:Monodrome is 98%, 97%, average 98%.Metallographic structure is ferrite+pearlite, and grain size is 13 grades.
Comparative example 1
X60 pipe line steels thick 14mm, the chemical composition of requirement identical with the use of embodiment 1.Steel billet relation reheating temperature is 1207 DEG C, roughing uses 5 passes, and each percentage pass reduction is 20%, 20%, 20%, 26%, 29%, and roughing is opened 4 passages and removed Phosphorus water, roughing extreme trace time mill speed is 2.5m/s, workpiece thickness 55mm;Finish rolling is 7 frame hot continuous rollings, each passage pressure Rate is respectively 40%, 38%, 0,26%, 0,10%, 9%, and entrance finishing temperature is 970 DEG C, and finishing temperature is 820 DEG C;Finish rolling After end, 650 DEG C are cooled to 20 DEG C/s cooling velocity, 5s is incubated, is then cooled to 600 DEG C with 10 DEG C/s cooling velocity Batch.
After testing, the X60 pipeline steel mechanical properties that this comparative example is produced are:Rt0.5:469MPa, Rm:565MPa, A: 43.5%, Rt0.5/Rm:0.83, -20 DEG C of Charpy-V impact powers:190.1J, -20 DEG C of DWTT drop hammer section of shear ratio:Monodrome is 72%, 65%, average 69%.
Comparative example 2
X42 pipe line steels thick 16mm, using the chemical composition of requirement same as Example 2.Steel billet relation reheating temperature is 1191 DEG C, roughing uses 5 passes, and each percentage pass reduction is 21%, 20%, 24%, 26%.26%, roughing is opened 4 passages and removed Phosphorus water, roughing extreme trace time mill speed is 3.0m/s, workpiece thickness 55mm;Finish rolling is 7 frame hot continuous rollings, each passage pressure Rate is respectively 34%, 32%, 0,20%, 0,11%, 9%, and entrance finishing temperature is 970 DEG C, and finishing temperature is 830 DEG C;Finish rolling After end, 700 DEG C are cooled to 15 DEG C/s cooling velocity, air cooling 5s, is then cooled to 580 DEG C with 12 DEG C/s cooling velocity Batch.
After testing, the X42 pipeline steel mechanical properties that this comparative example is produced are:Rt0.5:315MPa, Rm:405MPa, A: 46%, Rt0.5/Rm:0.77, -10 DEG C of Charpy-V impact powers:157J, -10 DEG C of DWTT drop hammer section of shear ratio:Monodrome is 70%, 56%, average 63%.
Comparative example 3
X52 pipe line steels thick 16mm, using chemical composition same as Example 3.Steel billet relation reheating temperature is 1169 DEG C, Roughing uses 5 passes, and each percentage pass reduction is 24%, 21%, 20%, 26%, 27%, and 4 passage dephosphorization water are opened in roughing, slightly It is 2.0m/s, workpiece thickness 56mm to roll extreme trace time mill speed;Finish rolling is 7 frame hot continuous rollings, each percentage pass reduction difference For 34%, 33%, 0,20%, 0,10%, 9%, entrance finishing temperature is 990 DEG C, and finishing temperature is 840 DEG C;After finish rolling terminates, 690 DEG C are cooled to 20 DEG C/s cooling velocity, air cooling 5, then 640 DEG C is cooled to 10 DEG C/s cooling velocity and batches.
After testing, the X52 pipeline steel mechanical properties that this comparative example is produced are:Rt0.5:385MPa, Rm:480MPa, A: 38.5%, Rt0.5/Rm:0.80, -20 DEG C of Charpy-V impact powers:161.5J, -20 DEG C of DWTT drop hammer section of shear ratio:Monodrome is 60%, 74%, average 67%.

Claims (6)

1. improve think gauge pipeline steel block hammer performance method, steel billet is heated successively, roughing, finish rolling, section cooling and Batch, obtain think gauge pipe line steel finished product, it is characterised in that:
The heating-up temperature is 1150~1179 DEG C;
Roughing uses at least 5 passes, each pass deformation >=20%, wherein rear 2 pass deformation >=30%, roughing extreme trace Secondary 2.0~2.5mm/s of speed;
Start rolling temperature≤949 DEG C of finish rolling, finishing temperature are 730~780 DEG C;
After finish rolling terminates, first with 41~80 DEG C/s cooling velocity be cooled to 520~590 DEG C, 2~8s of air cooling, then with 15~ 25 DEG C/s cooling velocity is cooled to 500~579 DEG C and batched;
The microscopic structure of the think gauge pipe line steel is ultra-fine ferrite and pearlitic structrure, and its grain size is more than 12 grades;Pipe Line steel grade of steel is X60 and following rank;
The think gauge pipe line steel consists of the following components in percentage by weight:C:0.03~0.07%, Si:0.10~ 0.35%, Mn:0.80~1.60%, Nb≤0.05%, 0 < Cr≤0.30%, V≤0.05%, remaining is for Fe and unavoidably Impurity.
2. the method according to claim 1 for improving think gauge pipeline steel block hammer performance, it is characterised in that:The think gauge The thickness of pipe line steel finished product is more than 14mm.
3. the method according to claim 1 for improving think gauge pipeline steel block hammer performance, it is characterised in that:Think gauge pipeline The thickness of steel finished product is 14~18mm.
4. the method according to claim 2 for improving think gauge pipeline steel block hammer performance, it is characterised in that:Steel billet thickness 200~250mm, the workpiece thickness after roughing are 56~58mm.
5. the method according to claim 1 for improving think gauge pipeline steel block hammer performance, it is characterised in that:Roughing uses 5 ~7 passes, and at least open 4 passage dephosphorization water.
6. the method according to claim 1 for improving think gauge pipeline steel block hammer performance, it is characterised in that:The pipe line steel Grade of steel is X42, X52 or X60.
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CN104109744B (en) * 2014-07-28 2016-11-09 攀钢集团西昌钢钒有限公司 The method improving pipeline steel block hammer performance
CN104694719A (en) * 2015-03-12 2015-06-10 攀钢集团西昌钢钒有限公司 Thick-specification pipeline steel cooling method
CN104998901A (en) * 2015-08-10 2015-10-28 首钢总公司 Hot rolling technology for pipeline rolled steel plate

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