CN106563695A - Low-yield-ratio high-strength pipeline steel production method - Google Patents

Low-yield-ratio high-strength pipeline steel production method Download PDF

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CN106563695A
CN106563695A CN201610975595.1A CN201610975595A CN106563695A CN 106563695 A CN106563695 A CN 106563695A CN 201610975595 A CN201610975595 A CN 201610975595A CN 106563695 A CN106563695 A CN 106563695A
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temperature
rolling
steel
austenite
cooling
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CN106563695B (en
Inventor
朱坦华
李玉谦
杜琦铭
刘红艳
梅东贵
姚宙
成慧梅
郝宾宾
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HBIS Co Ltd Handan Branch
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B1/00—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations
    • B21B1/22—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling plates, strips, bands or sheets of indefinite length
    • B21B1/222—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling plates, strips, bands or sheets of indefinite length in a rolling-drawing process; in a multi-pass mill
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B37/00—Control devices or methods specially adapted for metal-rolling mills or the work produced thereby
    • B21B37/48—Tension control; Compression control
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B37/00—Control devices or methods specially adapted for metal-rolling mills or the work produced thereby
    • B21B37/74—Temperature control, e.g. by cooling or heating the rolls or the product
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B37/00—Control devices or methods specially adapted for metal-rolling mills or the work produced thereby
    • B21B37/74—Temperature control, e.g. by cooling or heating the rolls or the product
    • B21B37/76—Cooling control on the run-out table
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/10—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of tubular bodies
    • C21D8/105—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of tubular bodies of ferrous alloys
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/26—Ferrous alloys, e.g. steel alloys containing chromium with niobium or tantalum
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/28—Ferrous alloys, e.g. steel alloys containing chromium with titanium or zirconium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/38—Ferrous alloys, e.g. steel alloys containing chromium with more than 1.5% by weight of manganese
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B1/00—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations
    • B21B1/22—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling plates, strips, bands or sheets of indefinite length
    • B21B2001/225—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling plates, strips, bands or sheets of indefinite length by hot-rolling
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/001—Austenite
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/005—Ferrite

Abstract

The invention relates to a low-yield-ratio high-strength pipeline steel production method. The method includes the working processes of steelmaking-continuous casting, casting blank heating, casting blank control rolling, steel plate control cooling and straightening through a straightening machine; in the working process of rolling, during austenite crystalline region elongation rolling, the single track reduction rate is not lower than 16%, the accumulated valid reduction rate is not lower than 70%, and the austenite crystalline region single track reduction rate is not higher than 18%; and in the working process of control cooling, the austenite crystalline region rolling starting temperature is lower than Ar3 temperature by 20 DEG C to 30 DEG C, the rolling temperature scope is located in an austenite and ferrite coexistence region, the cooling starting temperature is lower than the Ar1 temperature, and large phase change stress is prevented from being generated in the cooling process. A pipeline steel product produced through the process has the high strength, and meanwhile has the good tenacity and the excellent yield ratio scope; and the contradiction of high strength and low yield ratio of the iron and steel industry pipeline steel series products is solved, and the best level of similar enterprises in China is achieved.

Description

A kind of production method of low yield strength ratio high-strength line-pipe steel
Technical field
The present invention relates to a kind of production method of low yield strength ratio high-strength line-pipe steel, belongs to metal rolled technical field.
Background technology
, used as transfer oil and the raw material of natural gas line, safety is most important, and yield tensile ratio is to characterize material for pipe line steel From initial plastic deformation to the deformability of eventual failure, so yield tensile ratio is mechanical performance index important in pipe line steel.Bend It is strong than less, the deformability of material is bigger, and strength margin is bigger；Yield tensile ratio is bigger, and the plastic range after material yield is less, Easier generation rupture failure.Steel pipe bear it is intrinsic pressure be deformed into rupture before, circumferential deformation exist a ultimate value, the value is with steel The yield tensile ratio of pipe increases and reduces.So for the security consideration to pipeline, the general requirement of yield tensile ratio of pipe line steel can not be more than A certain particular value.At present, requirement of each pipeline specifications to this index both at home and abroad is not quite similar, and general X65 ranks are claimed below Requirement of the pipeline of 0.85, X70 or higher level to yield tensile ratio can not be more than can be loosened to 0.90 or even 0.93.
For pipeline product made from steel, with the increase of intensity rank, the increase of yield strength Rt0.5 is much larger than tensile strength Rm Increase, directly result in the super upper limit of high intensity levels pipeline product made from steel yield tensile ratio.For pipe line steel production field, long-standing problem is wide The problem of big steel enterprise is the contradiction between " high intensity " and " low yield strength ratio " performance；It is exceeded then tight that yield tensile ratio occurs in pipe line steel Taboo is used, and to tubulation producer and vast iron and steel enterprise greatly puzzlement is caused.
The content of the invention
The technical problem to be solved is to provide a kind of production method of low yield strength ratio high-strength line-pipe steel, passes through Controlled rolling and cooling technique, change the percentage composition of tiny acicular ferrite+bainite two-phase in pipe line steel, have steel plate Have good toughness while high intensity concurrently, reach the purpose of final control pipe line steel yield tensile ratio.
The present invention for the technical scheme that adopted of solution above-mentioned technical problem for：
A kind of production method of low yield strength ratio high-strength line-pipe steel, including steel smelting-continuous casting, heating strand, strand controlled rolling, steel Plate control is cooled down and the straight operation of straightener sedan-chair, and its improvements is：
In the controlled rolling operation, the first rolling process austenite recrystallization area adopts big reduction system, single pass during elongation rolling Reduction ratio is not less than 16%, accumulates effective reduction ratio and is not less than 70%, the second rolling process austenite Unhydrated cement single pass reduction ratio Not higher than 18%；
In the control refrigerating work procedure, the second rolling process austenite Unhydrated cement start rolling temperature is less than 20 ~ 30 DEG C of Ar3 temperature, makes Rolling temperature range is located at " austenite+ferrite " coexistence region, and operation of rolling steel plate is no longer recrystallized；Begin to cool down temperature Less than Ar1 temperature, it is to avoid produce larger transformation stress in cooling procedure.
A kind of production method of above-mentioned low yield strength ratio high-strength line-pipe steel, the first rolling process is difficult to understand in the controlled rolling operation The big reduction system that family name's body recrystallization zone is adopted for：Strand broadening rolling terminate after, elongation rolling when the first percentage pass reduction not Less than 16%, afterwards each percentage pass reduction is stepped up to 20 ~ 25%, is accumulated effective reduction ratio and is not less than 70%；Second rolling process Last percentage pass reduction of austenite Unhydrated cement is not higher than 12%；
In the control refrigerating work procedure, the start rolling temperature of the second rolling process austenite Unhydrated cement is 780 ~ 810 DEG C, is begun to cool down Temperature is 670 ~ 690 DEG C；Control chill formula adopts DQ+ACC two-stage coolings, DQ to control the cold section of cooling rate with 20 ~ 30 DEG C/s and quickly lead to Bainite transformation temperature area is crossed, the bainite of corresponding proportion is obtained；ACC control the cold section of cooling rate with 10 ~ 20 DEG C/s be cooled to it is eventually cold 150 ~ 220 DEG C of temperature, while avoiding generating martensitic structure, reduces ACC and controls cold section of steel plate thermal stress, obtains good plate Form quality amount.
A kind of production method of above-mentioned low yield strength ratio high-strength line-pipe steel, the formulation foundation of the controlled rolling operation For：The level pipeline pipeline steel hyperthermia stress-strain curve is drawn initially with the research of the hot modeling test machines of Gleeble 3500, it is determined that , at 950 ~ 1050 DEG C, rate of deformation is in 5 ~ 10s for deformation temperature-1, the critical compresibility of occurrence dynamics recrystallization is 16 ~ 20%, thus Formulate the soft reduction process of austenite recrystallization area and Unhydrated cement；
In the control refrigerating work procedure, show that the level pipeline pipeline steel austenite connects initially with the thermal modeling tests of Gleeble 3500 Continuous cooling transformation curve, draws accordingly Ar3 temperature and Ar1 temperature and sets start rolling temperature and begin to cool down temperature.
A kind of production method of above-mentioned low yield strength ratio high-strength line-pipe steel, the first rolling process austenite recrystallization area Effectively reduction ratio refers to the reduction ratio of percentage pass reduction >=16%, it is ensured that austenite can be recrystallized.
A kind of production method of above-mentioned low yield strength ratio high-strength line-pipe steel, strand composition in the steel smelting-continuous casting operation Weight percentage ranges are：C：0.03 ~ 0.07%, Si：≤ 0.10%, Mn：1.50 ~ 1.70%, P：≤ 0.025%, S：≤ 0.015%, Als：0.015 ~ 0.045%, Nb：0.055 ~ 0.070%, Ti：0.010 ~ 0.030%, Cr：0.20~0.30%；Pcm：0.12 ~ 0.18%；The rolling process first, by heating strand to 1100 ~ 1150 DEG C, is incubated 320 ~ 360min using double rolling process rollings； De-scaling water under high pressure is fully open, and de-scaling water pressure is 20 ~ 30Mpa, thoroughly removes surface stove life oxide skin；Then carry out first to roll Journey austenite recrystallization area rolls, and start rolling temperature is 1020～1080 DEG C, the first percentage pass reduction >=16%, afterwards each passage pressure Lower rate is stepped up to 20 ~ 25%, accumulates effective reduction ratio >=70%, the second rolling process austenite Unhydrated cement start rolling temperature temperature Scope is 780 ~ 810 DEG C, single pass reduction ratio≤18%, last percentage pass reduction≤12%.It is 670 ~ 690 to open cold temperature range DEG C, DQ controls the cold section of cooling rate with 20 ~ 30 DEG C/s and is quickly cooled to 400 ~ 430 DEG C, and it is cold that ACC controls the cold section of cooling rate with 10 ~ 20 DEG C/s But 150 ~ 220 DEG C of final cooling temperature is arrived；1 ~ 4 passage is aligned subsequently into straightener, straightening temperature is 100 ~ 200 DEG C.
The present invention show that the level pipeline pipeline steel hyperthermia stress-strain is bent using the research of the hot modeling test machines of Gleeble 3500 Line, determines first rolling process austenite recrystallization area's deformation temperature at 950 ~ 1050 DEG C, and rate of deformation is in 5 ~ 10s-1, there is austenite The critical compresibility of dynamic recrystallization is 16 ~ 20%, in order that pipe line steel occurrence dynamics recrystallization, the effective reduction ratio setting of passage For >=16%, original fine austenite crystal grain is obtained；Second rolling process austenite Unhydrated cement is not in order that pipe line steel is moved State is recrystallized, and percentage pass reduction is set as≤18%, steel plate deformed is recrystallized from occurrence dynamics, and is retained in metal inside Distortion energy, there is provided more ferrite forming core points.
Second rolling process austenite Unhydrated cement start rolling temperature of the invention is 780 ~ 810 DEG C, and rolling temperature range is located at " difficult to understand Family name's body+ferrite " coexistence region, operation of rolling steel plate is not being recrystallized, and steel plate inside retains distortional strain energy, and main purpose is to increase Plus ferrite forming core point, tiny acicular ferrite after a certain proportion of flattening is formed in the operation of rolling, it is tiny to finally give Acicular ferrite and bainite duplex structure prepare.
Using the high tensile pipeline steel cut deal product of present invention process production, heterogeneous microstructure is：30 ~ 45% needle-like ferrum The MA islands of ferritic+40 ~ 65% bainite+0 ~ 5%；485 ~ 635MPa of yield strength, 560 ~ 760MPa of tensile strength, elongation percentage（A50） >=24%, yield tensile ratio scope is 0.78 ~ 0.83, -20 DEG C of sections of shear 100% of dropping hammer, -30 DEG C of impact shear areas 100%, steel plate Vickers hardness scope in lateral cross section（200~240）HV10.
The positive effect of the present invention：
The pipeline product made from steel of present invention process production, not only with higher intensity, while with good toughness and excellent Yield tensile ratio scope, solve the contradiction between steel industry pipe line steel series of products " high intensity " and " low yield strength ratio " performance, Reach domestic type of industry best level.In high tensile pipeline steel production technical field, it is good to be that China's steel industry is served Take the lead and exemplary role, providing for national same type production line is worth the successful experience of reference, social benefit is huge.
Description of the drawings
It is 5s that Fig. 1 is embodiment of the present invention target steel grade strain rate-1When, load-deformation curve under different rolling temperatures；
Fig. 2 is embodiment of the present invention target steel grade austenite Continuous Cooling Transformation Curve；
Fig. 3 is the microstructure at the pipe line steel 1/4 of the embodiment of the present invention 1；
Fig. 4 is the microstructure at the pipe line steel 1/2 of the embodiment of the present invention 1；
Fig. 5 is the microstructure at the pipe line steel 1/4 of the embodiment of the present invention 2；
Fig. 6 is the microstructure at the pipe line steel 1/2 of the embodiment of the present invention 2；
Fig. 7 is the microstructure at the pipe line steel 1/4 of the embodiment of the present invention 3；
Fig. 8 is the microstructure at the pipe line steel 1/2 of the embodiment of the present invention 3.
Specific embodiment
The present invention provides a kind of production method of low yield strength ratio high-strength line-pipe steel, initially with the hot-dies of Gleeble 3500 Intend testing machine goal in research pipe line steel hyperthermia stress-strain curve, draw rate of deformation in 5 ~ 10s-1, deformation temperature 950 ~ 1050 DEG C, the critical compresibility that Austenite Dynamic Recrystallization occurs is 16 ~ 20%, in order that pipe line steel occurs austenite dynamic again Crystallization, the effective reduction ratio of the first rolling process austenite recrystallization area passage should be greater than being equal to 16%, be set as >=16%, obtain original Fine austenite crystal grain, the second rolling process austenite Unhydrated cement, in order that pipe line steel not occurrence dynamics recrystallization, passage pressure Rate answers≤18%；Secondly target pipeline steel austenite Continuous Cooling Transformation Curve is drawn using the thermal modeling tests of Gleeble 3500, Draw Ar3 and Ar1 temperature, the second rolling process austenite Unhydrated cement start rolling temperature of setting is lower than Ar3 temperature 20 ~ 30 DEG C, i.e., 780 ~ 810 DEG C, rolling temperature range is located at " austenite+ferrite " coexistence region, to finally give tiny acicular ferrite and bainite Duplex structure prepares；Cold temperature is opened less than Ar1 temperature, 670 ~ 690 DEG C is set to, it is to avoid larger phase transformation is produced in cooling procedure Stress, improves strip shape quality in cooling procedure；Control chill formula adopts two-stage cooling, first paragraph DQ to control cold section with 20 ~ 30 DEG C/s Cooling rate quickly through bainite transformation temperature area, be cooled to 400 ~ 430 DEG C, obtain the bainite of corresponding proportion, second segment ACC The cold section of cooling rate with 10 ~ 20 DEG C/s of control is cooled to 150 ~ 220 DEG C of final cooling temperature, and the second cooling section slow cooling can avoid generating geneva While body is organized, the second cooling section steel plate thermal stress is reduced, obtain good strip shape quality.
Specific production technology of the invention includes：Steel smelting-continuous casting operation production strand, heating strand operation eliminate strand temperature Degree gradient, strand controlled rolling operation, steel plate control refrigerating work procedure and the straight operation of straightener sedan-chair；Strand composition weight in continuous casting working procedure Measuring percentage range is：C：0.03 ~ 0.07%, Si：≤ 0.10%, Mn：1.50 ~ 1.70%, P：≤ 0.025%, S：≤ 0.015%, Als：0.015 ~ 0.045%, Nb：0.055 ~ 0.070%, Ti：0.010 ~ 0.030%, Cr：0.20~0.30%；Pcm：0.12~ 0.18%；In double rolling process rolling process, first, by heating strand to 1100 ~ 1150 DEG C, 320-360min is incubated；De-scaling water under high pressure Fully open, de-scaling water pressure is 20 ~ 30Mpa, thoroughly removes surface stove life oxide skin；Then the first rolling process austenite is carried out again Crystal region is rolled, and start rolling temperature is 1020～1080 DEG C, the first percentage pass reduction >=16%, and later each passage is stepped up 20 ~ 25%, effective reduction ratio >=70% of accumulation, the second 780 ~ 810 DEG C of rolling process austenite Unhydrated cement start rolling temperature temperature range, Single pass reduction ratio≤18%, last percentage pass reduction≤12%；It is 670 ~ 690 DEG C to open cold temperature range, DQ control cold section with 20 ~ The cooling rate of 30 DEG C/s is quickly cooled to 400 ~ 430 DEG C, ACC control the cold section of cooling rate with 10 ~ 20 DEG C/s be cooled to final cooling temperature 150 ~ 220℃；1 ~ 4 passage is aligned subsequently into straightener, straightening temperature is 100 ~ 200 DEG C.
By the following examples, the invention will be further described, and following examples experiment steel grade is that 485MPa ranks are high Strong pipeline steel medium plate product；The level pipeline pipeline steel national standard requires yield strength 485-635MPa, tensile strength 570- 760MPa, yield tensile ratio is not more than 0.93, due to the particularity of high-grade pipe line product made from steel use environment（Require low-temperature resistance, anti- The performances such as shake）, user typically requires yield tensile ratio 0.83-0.88, improves the safety for using of pipe line steel.
Initially with the hot modeling test machine goal in research pipe line steel hyperthermia stress-strain curves of Gleeble 3500, change is drawn Shape speed is in 5 ~ 10s-1, at 950 ~ 1050 DEG C, the critical compresibility that Austenite Dynamic Recrystallization occurs is 15 ~ 20% to deformation temperature； Secondly target pipeline steel austenite Continuous Cooling Transformation Curve is drawn using the thermal modeling tests of Gleeble 3500, according to above-mentioned knot Fruit carries out the formulation of austenite recrystallization area and austenite Unhydrated cement reduction system；Carry out austenite Unhydrated cement temperature The formulation of control system；Carry out DQ+ACC and open cold temperature and final cooling temperature system, and the formulation of cooldown rate；Below by way of three Embodiment is specifically addressed：
Embodiment 1：By smelt obtain purer molten steel, after be casting continuously to form strand through conticaster, its composition by weight percent For：C：0.03%, Si：0.025%, Mn：1.50%, P：0.0018%, S：0.006%, Als：0.015%, Nb：0.055%, Ti： 0.030%, Cr：0.20%；Pcm：0.13%；By heating strand to 1100 DEG C, 320min is incubated；De-scaling water under high pressure is fully open, removes Squama water pressure is 22Mpa, thoroughly removes surface stove life oxide skin；Then the rolling of the first rolling process austenite recrystallization area is carried out, is opened Temperature being rolled for 1020 DEG C, after the rolling of strand broadening terminates, being rolled using four-pass during elongation rolling, percentage pass reduction is respectively 16%th, 18%, 18%, 25%, effective reduction ratio 77% is accumulated, the second 780 DEG C of rolling process start rolling temperature temperature range is rolled using four-pass System, percentage pass reduction is respectively 13%, 15%, 17%, 10%；Open 670 DEG C of cold temperature, DQ controls the fast quickly cooling of cold section of cooling rate with 20 DEG C/s But to 400 DEG C, ACC controls the cold section of cooling rate with 10 DEG C/s and is cooled to 150 DEG C of final cooling temperature；3 passages are aligned subsequently into straightener, Straightening temperature is 140 DEG C.
The pipe line steel heterogeneous microstructure of production is：The lath of 34% acicular ferrite+64% and granular bainite+2%MA islands； Yield strength 565MPa, tensile strength 681MPa, elongation percentage（A50）30%, yield tensile ratio scope is 0.83, -20 DEG C of shear surfaces that drop hammer Product 100%, -30 DEG C of impact shear areas 100%, Vickers hardness 208HV10 in steel plate lateral cross section；Fully meet 485MPa ranks Pipe line steel " low yield strength ratio particular service requirement " is required.
Embodiment 2：By smelt obtain purer molten steel, after be casting continuously to form strand through conticaster, its Ingredients Weight hundred Point ratio is：C：0.05%, Si：0.06%, Mn：1.61%, P：0.013%, S：0.005%, Als：0.025%, Nb：0.059, Ti： 0.020%, Cr：0.26%；Pcm：0.15%；By heating strand to 1130 DEG C, 340min is incubated；De-scaling water under high pressure is fully open, removes Squama water pressure is 26Mpa, thoroughly removes surface stove life oxide skin；Then the rolling of the first rolling process austenite recrystallization area is carried out, is opened Temperature being rolled for 1050 DEG C, after the rolling of strand broadening terminates, being rolled using four-pass during elongation rolling, percentage pass reduction is respectively 16%th, 17%, 19%, 20%, effective reduction ratio 72% is accumulated, the second 795 DEG C of rolling process austenite Unhydrated cement start rolling temperature is adopted Four-pass is rolled, and percentage pass reduction is respectively 12%, 14%, 16%, 10%.685 DEG C of cold temperature is opened, DQ controls cold section with 27.3 DEG C/s's Cooling rate is quickly cooled to 415 DEG C, and ACC controls the cold section of cooling rate with 15.5 DEG C/s and is cooled to 200 DEG C of final cooling temperature；Subsequently into aligning Machine aligns 1 passage, and straightening temperature is 160 DEG C；
The pipe line steel heterogeneous microstructure of production is：Bainite+3%MA the islands of 40% acicular ferrite+57%；Yield strength 540MPa, Tensile strength 683MPa, elongation percentage（A50）34%, yield tensile ratio scope is 0.79, -20 DEG C of sections of shear 100% of dropping hammer, -30 DEG C of punchings The section of shear 100% is hit, Vickers hardness scope 213HV10 in steel plate lateral cross section；Fully meet 485MPa level pipeline pipeline steels " low Yield tensile ratio particular service requirement " is required.
Embodiment 3：By smelt obtain purer molten steel, after be casting continuously to form strand through conticaster, its Ingredients Weight hundred Point ratio is：C：0.07%, Si：0.08%, Mn：1.70%, P：0.025%, S：≤ 0.007%, Als：0.045%, Nb：0.070%, Ti： 0.010%, Cr：0.30%；Pcm：0.18%；By heating strand to 1150 DEG C, 360min is incubated；De-scaling water under high pressure is fully open, removes Squama water pressure is 30Mpa, thoroughly removes surface stove life oxide skin；Then the rolling of the first rolling process austenite recrystallization area is carried out, is opened Temperature being rolled for 1080 DEG C, after the rolling of strand broadening terminates, being rolled using four-pass during elongation rolling, percentage pass reduction is respectively 17%th, 18%, 19%, 22%, accumulate effective reduction ratio 76%, the second rolling process austenite Unhydrated cement start rolling temperature temperature range 810 DEG C, being rolled using four-pass, percentage pass reduction is respectively 12%, 15%, 15%, 10%, opens 690 DEG C of cold temperature, and DQ controls cold section with 30 DEG C/cooling rate of s is quickly cooled to 430 DEG C, ACC controls the cold section of cooling rate with 20 DEG C/s and is cooled to 220 DEG C of final cooling temperature；Subsequently into Straightener aligns 4 passages, and straightening temperature is 200 DEG C.
The pipe line steel heterogeneous microstructure of production is：Bainite+0%MA the islands of 45% acicular ferrite+55%；Yield strength 515MPa, tensile strength 636MPa, elongation percentage（A50）33%, yield tensile ratio scope is 0.81, -20 DEG C of sections of shear 100% of dropping hammer, - 30 DEG C of impact shear areas 100%, Vickers hardness 220HV10 in steel plate lateral cross section fully meets 485MPa level pipeline pipeline steels " low yield strength ratio particular service requirement " is required.

Claims (5)

1. a kind of production method of low yield strength ratio high-strength line-pipe steel, including steel smelting-continuous casting, heating strand, strand controlled rolling, Steel plate control cooling and the straight operation of straightener sedan-chair, it is characterised in that：
In the controlled rolling operation, the first rolling process austenite recrystallization area adopts big reduction system, single pass during elongation rolling Reduction ratio is not less than 16%, accumulates effective reduction ratio and is not less than 70%, the second rolling process austenite Unhydrated cement single pass reduction ratio Not higher than 18%；
In the control refrigerating work procedure, the second rolling process austenite Unhydrated cement start rolling temperature is less than 20 ~ 30 DEG C of Ar3 temperature, makes Rolling temperature range is located at " austenite+ferrite " coexistence region, and operation of rolling steel plate is no longer recrystallized；Begin to cool down temperature Less than Ar1 temperature, it is to avoid produce larger transformation stress in cooling procedure.
2. a kind of production method of low yield strength ratio high-strength line-pipe steel as claimed in claim 1, it is characterised in that：The control The big reduction system that the first rolling process austenite recrystallization area adopts in rolling process for：After the rolling of strand broadening terminates, elongation is rolled First percentage pass reduction is not less than 16% when processed, and afterwards each percentage pass reduction is stepped up to 20 ~ 25%, accumulates effective reduction ratio not Less than 70%；Last percentage pass reduction of the second rolling process austenite Unhydrated cement is not higher than 12%；
In the control refrigerating work procedure, the start rolling temperature of the second rolling process austenite Unhydrated cement is 780 ~ 810 DEG C, is begun to cool down Temperature is 670 ~ 690 DEG C；Control chill formula adopts DQ+ACC two-stage coolings, DQ to control the cold section of cooling rate with 20 ~ 30 DEG C/s and quickly lead to Bainite transformation temperature area is crossed, the bainite of corresponding proportion is obtained；ACC control the cold section of cooling rate with 10 ~ 20 DEG C/s be cooled to it is eventually cold 150 ~ 220 DEG C of temperature, while avoiding generating martensitic structure, reduces ACC and controls cold section of steel plate thermal stress, obtains good plate Form quality amount.
3. a kind of production method of low yield strength ratio high-strength line-pipe steel as claimed in claim 1 or 2, it is characterised in that：It is described The formulation of controlled rolling operation is according to being：The level pipeline pipeline steel is drawn initially with the research of the hot modeling test machines of Gleeble 3500 Hyperthermia stress-strain curve, determines deformation temperature at 950 ~ 1050 DEG C, and rate of deformation is in 5 ~ 10s-1, what occurrence dynamics were recrystallized faces Boundary's reduction ratio is 16 ~ 20%, thus formulates the soft reduction process of austenite recrystallization area and Unhydrated cement；
In the control refrigerating work procedure, show that the level pipeline pipeline steel austenite connects initially with the thermal modeling tests of Gleeble 3500 Continuous cooling transformation curve, draws accordingly Ar3 temperature and Ar1 temperature and sets start rolling temperature and begin to cool down temperature.
4. a kind of production method of low yield strength ratio high-strength line-pipe steel as claimed in claim 1 or 2, it is characterised in that：It is described Effective reduction ratio in the first rolling process austenite recrystallization area refers to the reduction ratio of percentage pass reduction >=16%, it is ensured that austenite can Recrystallize.
5. a kind of production method of low yield strength ratio high-strength line-pipe steel as claimed in claim 1, it is characterised in that：The refining Strand composition by weight percent scope is in steel-continuous casting working procedure：C：0.03 ~ 0.07%, Si：≤ 0.10%, Mn：1.50 ~ 1.70%, P：≤ 0.025%, S：≤ 0.015%, Als：0.015% ~ 0.045%, Nb：0.055 ~ 0.070%, Ti：0.010 ~ 0.030%, Cr： 0.20~0.30%；Pcm：0.12 ~0.18%；The rolling process using double rolling processes rollings, first, by heating strand to 1100 ~ 1150 DEG C, it is incubated 320 ~ 360min；De-scaling water under high pressure is fully open, and de-scaling water pressure is 20 ~ 30Mpa, thoroughly removes surface stove Raw oxide skin；Then the rolling of the first rolling process austenite recrystallization area is carried out, start rolling temperature is 1020～1080 DEG C, the first passage pressure Lower rate >=16%, afterwards each percentage pass reduction be stepped up to 20 ~ 25%, accumulate effective reduction ratio >=70%, the second rolling process austenite Unhydrated cement start rolling temperature temperature range is 780 ~ 810 DEG C, single pass reduction ratio≤18%, last percentage pass reduction≤ 12%, it is 670 ~ 690 DEG C to open cold temperature range, and DQ controls the cold section of cooling rate with 20 ~ 30 DEG C/s and is quickly cooled to 400 ~ 430 DEG C, ACC The cold section of cooling rate with 10 ~ 20 DEG C/s of control is cooled to 150 ~ 220 DEG C of final cooling temperature；1 ~ 4 passage, aligning are aligned subsequently into straightener Temperature is 100 ~ 200 DEG C.
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CN107587072A (en) * 2017-09-01 2018-01-16 包头钢铁（集团）有限责任公司 A kind of X60 pipe line steels and preparation method thereof
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CN107641768A (en) * 2017-09-08 2018-01-30 河钢股份有限公司邯郸分公司 The production method of big wall thickness straight-line joint submerged arc welding tube line steel plate
CN109735698A (en) * 2019-01-31 2019-05-10 东北大学 Manganese TRIP steel and its method of low temperature process forming in a kind of high-performance
CN111842546A (en) * 2020-07-10 2020-10-30 首钢集团有限公司 Equipment and method for improving TMCP wide and thick plate secondary plate shape
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CN113637922A (en) * 2020-04-27 2021-11-12 宝山钢铁股份有限公司 Economical low-yield-ratio high-strength steel and manufacturing method thereof
CN111842546A (en) * 2020-07-10 2020-10-30 首钢集团有限公司 Equipment and method for improving TMCP wide and thick plate secondary plate shape

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