CN104089109B - A kind of 625MPa grades of UOE welded tube and its manufacture method - Google Patents

A kind of 625MPa grades of UOE welded tube and its manufacture method Download PDF

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CN104089109B
CN104089109B CN201410306696.0A CN201410306696A CN104089109B CN 104089109 B CN104089109 B CN 104089109B CN 201410306696 A CN201410306696 A CN 201410306696A CN 104089109 B CN104089109 B CN 104089109B
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welding
steel
forming
steel pipe
625mpa
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CN104089109A (en
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章传国
郑磊
张备
黄卫锋
吴扣根
徐国栋
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Baoshan Iron and Steel Co Ltd
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    • 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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23P—METAL-WORKING NOT OTHERWISE PROVIDED FOR; COMBINED OPERATIONS; UNIVERSAL MACHINE TOOLS
    • B23P15/00—Making specific metal objects by operations not covered by a single other subclass or a group in this subclass
    • 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
    • C22C38/001—Ferrous alloys, e.g. steel alloys containing N
    • 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
    • C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
    • 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
    • C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
    • 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
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/42—Ferrous alloys, e.g. steel alloys containing chromium with nickel with copper
    • 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
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
    • 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
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/48—Ferrous alloys, e.g. steel alloys containing chromium with nickel 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
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/50—Ferrous alloys, e.g. steel alloys containing chromium with nickel with titanium or zirconium
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
    • F16L9/00—Rigid pipes
    • F16L9/17—Rigid pipes obtained by bending a sheet longitudinally and connecting the edges

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • General Engineering & Computer Science (AREA)
  • Arc Welding In General (AREA)

Abstract

A kind of 625MPa grades of UOE welded tube and its manufacture method, its chemical component weight percentage are C：0.015~0.080%, Si：0.1~0.5%, Mn：1.40~2.20%, P≤0.015%, S≤0.003%, Nb：0.03~0.10%, Ti：0.01~0.035%, Cu+Ni：0.20~0.50%, and Cu/Ni：1~2, Cr+Mo：0.3~0.6%, Ca：0.001~0.005%, Al：0.02~0.045%, N≤0.010%, O≤0.008%, remaining is Fe and is inevitably mingled with.Welded tube yield strength of the present invention is more than 85% higher than 700MPa, 20 DEG C of low-temperature impact works higher than 625MPa, tensile strength higher than 230J, 20 DEG C of DWTT shear fractures area percents, while having manufacturability.The welded tube can be used for oil-gas transportation and high strength structure field.

Description

A kind of 625MPa grades of UOE welded tube and its manufacture method
Technical field
The present invention relates to UOE welded tubes and its manufacture method, more particularly to a kind of 625MPa grades of UOE welded tube and its manufacturer Method, the UOE welded tubes can be used for the association area of oil-gas pipeline conveying, extra large work and other structural member applications.
Background technology
Under the overall background of " low-carbon economy " development, each main use steel industry of China will all increase green during " 12 " Color, low-carbon (LC), especially the use dynamics of energy-conserving and environment-protective structural section, the energy, building, automobile, household electrical appliances, container, engineering machinery etc. With steel industry requirement higher is proposed for the steel performance such as high intensity, corrosion-resistant, long-life.625MPa and above grade of steel The development and application positive adaptation of UOE welded tubes this trend, the product can apply to energy conduit, ocean engineering and building structure Deng field.
Pipeline is one of most economical efficient mode of movement of oil and gas transmission, and China's oil-gas pipeline construction has The developing history of many decades, pipeline material also develops into the API such as X42~X80 X series grade of steels from initial A, level-B steel, 550MPa grades of X80 is also the highest grade of steel of current large-scale application.Upgrading of the plumbing installations during " 12 " is to steel Quality proposes new demand, and the oil-gas pipeline main line construction of the five-year China will invest 350,000,000,000 yuan, and build three lines of transfering natural gas from the west to the east (Huo'erguosi-Shaoguan), four lines of transfering natural gas from the west to the east (Turfan-centre halfback), middle remote oil-gas pipeline (western part harbour Kyaukpyu city of Burma- Kunming), centre halfback-Chongqing-Kweiyang gas transmission line, the natural-gas transfer pipeline such as the line of Shan capital four.In order to save building time, reduce Pipeline takes up an area and invests, and the big throughput pipeline in 480 billion cubic meters/year turns into the emphasis of following pipe-line construction, thus 625MPa and The exploitation and application of higher intensity welded tube are not only contributed to reduce steel using amount, pipeline construction and operation cost are reduced, while may be used also Transfer efficiency is improved, is one of ideal chose of following pipe-line construction.
High intensity UOE welded tubes have the advantages that lightweight, intensity is high, long lifespan, are also widely used in ocean engineering, build Build, stake, the regeneration product of the can of pillar and other structural members.By improving intensity, this welded tube can significantly subtract Light construction weight, it is possible to achieve big height, the structure building of large span, reduces metal consumption, raises labour productivity；Further Improve toughness, can safety applications in environmental areas such as polar region, low temperature.High intensity welded tube is in Europe, America, Japan and Southeast Asia etc. Developed country has been carried out further investigation, and China is then in the starting stage.
The characteristics of composition design of existing high intensity UOE welded tubes, microscopic structure design and tubulation mode, is as follows：
In composition design, such as Chinese patent CN100398684 can significantly improve the strong of steel by using B microalloyings Degree, but the toughness of steel is relatively relatively low；Japan Patent JP61099660A designs to improve the anti-corrosion of welded tube using Cr, Ni alloy high Property, cost of alloy is higher；Chinese patent CN200780024813.2 is not defined to elemental gas such as N, O, but N, O high contains Amount damages the low-temperature flexibility and aging performance of steel.
In microscopic structure design, prior art is designed frequently with heterogeneous structure, such as Chinese patent Polygonal ferrites and more than 80% bainite microscopic structure design of the CN200480037950.6 using less than 20%, due to The presence for having boundary is unfavorable for improving the impact flexibility of steel, while the fluctuation of Phase Proportion easily causes performance inconsistency.
In tubulation mode, prior art is frequently with modes, such as Chinese patent such as helix tube, JCOE pipes and seamless pipes CN200710117991.1 carries out tubulation using double slit weldering, and dimensional accuracy is poor, and weld seam safety in utilization more long is poor；China Patent CN100398684, ZL200710185350.X, CN200710185346.3 are using JCOE tubulation modes, and which Residual stress is higher, cast size is poor, is unfavorable for site operation and welding；Also just like Chinese patent ZL201010112123.6, CN201010216400.8 use spiral welding tubulation mode, the same tubulation mode to expand without full pipe Footpath operation, residual stress distribution is uneven, cast is second-rate, while weld seam is more long, security reliability is relatively low.
The content of the invention
It is an object of the invention to provide a kind of 625MPa grades of UOE welded tube and its manufacture method, the welded tube yield strength is high In 625MPa, tensile strength higher than 700MPa, -20 DEG C of low-temperature impact works higher than 230J, -20 DEG C of DWTT shear fracture area percentages Number is more than 85%, while having manufacturability.The welded tube can be used for oil-gas transportation and high strength structure.
To reach above-mentioned purpose, the technical scheme is that：
625MPa grades of UOE welded tube external diametrical extents of the present invention areWall thickness range is 10.0~20.0mm. Steel plate uses C-Mn-Nb component systems, the composition design of low C alloy, and carries out sheet stock life using wide and heavy plate mill Produce, coordinate suitable controlled rolling and DQ+ACC Controlled cooling process, produce the high-intensity high-tenacity based on lower bainite Sheet stock；It is straight the UOE with high intensity, high tenacity to be obtained through the operation such as C, U, O forming and prewelding, interior weldering, outside weld, expanding Seam welded tube.
Specifically, a kind of 625MPa grades of UOE welded tube of the invention, its chemical component weight percentage is C：0.015~ 0.080%th, Si：0.1~0.5%, Mn：1.40~2.20%, P≤0.015%, S≤0.003%, Nb：0.03~0.10%, Ti：0.01~0.035%, Cu+Ni：0.20~0.50%, and Cu/Ni：1~2, Cr+Mo：0.3~0.6%, Ca：0.001~ 0.005%, Al：0.02~0.045%, N≤0.010%, O≤0.008%, remaining is Fe and is inevitably mingled with.
In the composition design of steel of the present invention：
Carbon C：Most basic intensified element.Carbon dissolution forms interstitial solid solution in steel, plays solution strengthening, and strong Carbide former forms Carbide Precipitation, then play a part of precipitation strength.But C too high to the ductility of steel, toughness and Welding performance is unfavorable；The intensity of the low steel of C too sinkings,.So C systems are 0.015~0.080%.
Silicon Si：Solution strengthening element, while be also the deoxidant element in steel, but too high levels can deteriorate the weldability of steel Can, while it is unfavorable for hot rolling iron scale removal in the operation of rolling, therefore content control is 0.1~0.5%.
Manganese Mn：The intensity of steel is improved by solution strengthening, is to compensate in steel to cause loss of strength most because of C content reduction Mainly, economic intensified element.Mn still expands the element of γ phase regions, it is possible to decrease γ → α phase transition temperatures of steel, helps to obtain Tiny phase-change product, can improve the toughness of steel；But Mn is easy segregation element, when Mn contents are higher, the Mn in casting cycle Easily in thickness of slab center segregation, the martensitic structure of hard phase is generated after the completion of rolling, the low-temperature flexibility and anti-dynamic for reducing material are torn Fragility energy.Therefore Mn contents are defined to 1.40~2.20% in the band present invention.
Niobium Nb：Nb is one of important element of low-carbon micro steel-alloy, the Nb strain induced precipitate shapes of solid solution in course of hot rolling Into Nb (N, C) particle, pinning crystal boundary suppresses growing up for deformed austeaite, and deformed austeaite phase is made through controlled rolling and control cooling It is changed into the tiny product with high dislocation density.Additionally, the Nb of solid solution is after batching, with second phase particles NbC in matrix Disperse educt, plays precipitation strength effect.Too low Nb content disperse educt DeGrains, do not have crystal grain thinning, reinforcing Matrix is acted on；Nb contents too high, are also easy to produce slab crackle, influence surface quality, while can severe exacerbation welding performance.This hair Bright middle Nb contents should be limited to 0.03~0.10%.
Titanium Ti：It is a kind of strong carbonitride-forming elements, the not molten carbonitride of Ti can hinder when steel is heated Only austenite crystal is grown up, and the TiN separated out during roughing in high temperature austenite area can effectively suppress Austenite Grain Growth.In addition In welding process, the TiN particles in steel can significantly prevent heat affected area crystal grain from growing up, so that the welding performance for improving steel plate is same When to improve welding heat affected zone impact flexibility have obvious effect.The control of Ti contents is 0.01~0.035% in the present invention.
Copper, nickel (Cu, Ni)：The intensity of steel can be improved by solution strengthening effect, while Cu can also improve the corrosion resistance of steel, Ni is conducive to improving toughness；Adding Ni by a certain percentage can improve the red brittleness that Cu easily causes in steel, reduce slab crackle with Stick up skin generation.Too high Cu, Ni increases cost and is unfavorable for welding, therefore Cu+Ni is limited in the present invention：0.20~0.50%, Require Cu/Ni simultaneously：1~2.
Chromium, Mo (Cr, Mo)：Hardenability, the important element of quenching degree of steel are improved, the intensity of steel, Liang Zheke is effectively improved With compound addition or individually addition, primarily serve phase transformation control and improve the structure property uniformity on thickness direction.But it is too high Chromium and manganese simultaneously add steel in, low melting point Cr-Mn composite oxides can be caused to be formed, in hot procedure formed surface split Line, while can severe exacerbation welding performance；Mo too high adds the content for increasing MA constituent elements, and On Impact Toughness is unfavorable.The present invention Regulation Cr+Mo：0.30~0.60%.
Nitrogen N：In micro alloyed steel, appropriate nitrogen content can play suppression again by forming dystectic TiN particles The effect of slab grain coarsening in heating process, improves the obdurability of steel.But when N content is too high, after timeliness high concentration from By N atom pinning dislocations, significantly improve yield strength, while damaging toughness.Therefore N≤0.010% is controlled in the present invention.
Oxygen O：For the pure steel smelting of low-alloy, it is required to carry out deoxidation treatment in smelting endpoint, to reduce casting cycle The bubble and oxide of middle generation are mingled with, and endoplasm, the low-temperature impact toughness of raising finished steel plate and the anti-dynamic for improving steel are torn Fragility energy.When oxygen content be higher than 80ppm when, the endoplasm defect such as field trash, stomata significantly increases, thus in the present invention control O≤ 0.008%.
Sulphur, phosphorus (S, P)：It is inevitable impurity element in steel, it is desirable to more low better.(it is less than by super-low sulfur 30ppm) and Ca treatment inclusion morphology control is carried out to sulfide, while control P content in below 150ppm, it is ensured that invention Steel has good low-temperature impact toughness.
Calcium (Ca)：The form of sulfide can be controlled by Ca treatment, improves the anisotropy of steel plate, improve low temperature tough Property, for the control range for ensuring optimum efficiency Ca is 0.0010~0.0050%.
Aluminium (Al)：It is that the element in steel is added for deoxidation, adds appropriate Al and be conducive to crystal grain thinning, improves steel Toughness and tenacity, the present invention in Al content control range be 0.02~0.045%.
Therefore, by crystal grain refinement, precipitation strength, phase transformation control etc. based on materials theory, employ relatively low C content, The composition design of Mn, Cu/Ni/Cr/Mo alloying high and Nb, Ti microalloying；And combine controlled rolling and control cooling Thermo-mechanical treatment process, obtain based on lower bainite for manufacturing the 625MPa grades of hot rolled steel plate of welded tube, with high intensity, The Mechanical Characteristics of high tenacity.
The manufacture method of 625MPa grades of UOE welded tube of the present invention, it is characterized in that, comprise the following steps：
1) continuous casting is smelted
Smelted by mentioned component, through smelting-LF+RH external refinings-continuous casting, obtain the continuous casting of 200~300mm thickness specifications Slab；
2) heat：1070~1200 DEG C of slab reheating temperature；
3) roughing：It is >=960 DEG C that roughing stops temperature；Middle base is thick：Middle base thickness 4t~8t, t are final finished steel plate Thickness, mm；
4) finish rolling：Finishing temperature is 730~820 DEG C；
5) DQ direct quenchings cooling：Final cooling temperature is 350~450 DEG C, cooldown rate >=30 DEG C/s；
6) ACC is quickly cooled down：Final cooling temperature is 80~350 DEG C, cooldown rate >=15 DEG C/s；
7) steel pipe forming welding, including steel pipe forming-UO shapings, steel-pipe welding；O forming compression ratio be 0.18~ 0.22%, wherein, during O forming compression ratio=(π × (pre- postwelding external diameter-wall thickness)-milling width after)/milling after width × 100%；
8) expanding E shapings：Steel pipe total length after welding is carried out it is expanding, it is expanding to meet the final tube type requirements of steel pipe Rate scope is 0.8%~1.2%, wherein, enlarging rate=(expanding rear outer diameter of steel pipes-expanding preceding outer diameter of steel pipes)/expanding preceding steel pipe External diameter × 100%.
Further, step 7) steel pipe forming welding welding preparation, including：
1) striking plate weld：In four corner welding striking steel plates of steel plate, it is mainly used in striking effect during welding；
2) milling side, groove size：By divided edge of steel plate size design.
Further, step 7) steel pipe forming welding in welded tube forming, including,
1) C shapings：Also known as crimp shaping, on crimp forming machine, the edge of steel plate is bent into institute by beader The shape for needing, it is ensured that the straight section of edges of boards is minimum during O forming；
2) forming U shaped articles：On forming U shaped articles machine, by the steel plate of pre-flanging through being once pressed into " U " type；
3) O forming：On O forming machine, by the steel plate after forming U shaped articles through being once pressed into " O " type；
4) high pressure water washing and drying：High pressure water washing will be carried out to weld the surfaces externally and internally of the steel pipe that cracks after shaping, gone Except the pollution such as iron scale, grease, dust；Entering drying oven after the completion of flushing immediately carries out drying and processing, and drying temperature is 100 DEG C ~300 DEG C.
Also, step 7) steel pipe forming welding in steel-pipe welding, including：
1) prewelding：The steel pipe that cracks after to O forming, makes its opposite side Accurate align, positioning, and use CO2Or Ar+CO2Protection Weldering carries out continuous prewelding welding, to ensure in follow-up arc stability during weldering, outside weld, it is ensured that final welding quality；
2) weldering in：
For 10.0~15.0mm wall thickness specifications welded tubes, carry out welding welding, the 1st in steel pipe using three submerged welding processes It is DC reverse connection, the 2nd, 3 is exchange, and gage of wire is 3.5~4.5mm；1st electric current is 550~650A, voltage is 22~ 30V；2nd, 3 electric currents are 450~600A, and voltage is 30~40V；
For 15.1~20.0mm wall thickness specifications welded tubes, using four submerged welding processes, the 1st electric current is DC reverse connection, 2nd, 3,4 is exchange, and gage of wire is 3.5~4.5mm；1st is DC reverse connection, and electric current is 1100~1200A, and voltage is 28~40V；2nd~4 electric current is 500~700A, voltage is 34~42V；
Speed of welding is 1.5~1.9m/min；Interior weldering solder flux is both needed to be dried in the range of 250~450 DEG C, dries Time >=2 hour；
3) outside weld：
For 10.0~15.0mm wall thickness specifications welded tubes, steel pipe outside weld welding, the 1st are carried out using three submerged welding processes It is DC reverse connection, the 2nd, 3 is exchange, and gage of wire is 3.5~4.5mm；1st electric current is 850~1000A, and voltage is 30 ~40V；2nd, 3 electric currents are 450~650A, and voltage is 35~45V；
For 15.1~20.0mm wall thickness specifications welded tubes, using four submerged welding processes, the 1st electric current is DC reverse connection, 2nd, 3,4 is exchange, and gage of wire is 3.5~4.5mm；1st electric current is 1100~1200A, and voltage is 28~40V；2nd ~4 electric currents are 500~700A, voltage is 34~42V；
Speed of welding is 1.3~1.8m/min；Outer-welding welding flux is both needed to be dried in the range of 250~450 DEG C, drying Time >=2 hour.
In addition, seam inspection after welding, including,
Welding line ultrasonic is detected a flaw：Using ultrasonic detection method, the weld defect such as detection postwelding crackle, layering, lack of penetration；
Weld seam x-ray inspection：Using x-ray inspection method, detection postwelding bubble, the point-like weld defect such as it is mingled with.
In addition, step 8) it is expanding after comprise the following steps：
9) welding line ultrasonic flaw detection：Using ultrasonic detection method, the weld defect such as expanding rear crackle, layering, lack of penetration is detected；
10) weld seam X-ray examination：Using x-ray inspection method, the point-like weld defect such as expanding rear bubble is detected, is mingled with；
11) chamfered edge：Steel pipe two ends are carried out with tack, chamfered edge treatment, is that job site butt welding offers convenience；
12) pipe end layering ultrasonic inspection：Ultrasonic flaw detection test is carried out to the steel tube end part after chamfered edge, lamination defect is prevented；
13) pipe end magnetic powder inspection：Magnetic powder detection is carried out to the steel tube end part after chamfered edge, lamination defect is prevented；
14) protection ring on：Pipe end is protected, it is ensured that the butt welding quality during steel pipe site operation.
In the design of above-mentioned mask-making technology, product of the present invention is controlled using the technique of strong cold+weak cold (DQ+ACC), DQ Strong cold stopping temperature is 350~450 DEG C, mainly suppresses middle temperature transformation by cooling rate high, avoids big heat exchange factor Fluctuating temperature is interval, is conducive to improving template, and obtain the low temperature phase change product with the matching of more high-strength tenacity；ACC weak colds are stopped Cold temperature is 80~350 DEG C, and the cold temperature of stopping of stabilization is mainly obtained by low cooling rate, promotes low temperature phase change to carry out, to obtain Single lower bainite tissue, so as to obtain preferably intensity and toughness matching.In the design of above-mentioned moulding process, by O (pressures Compression deformation), the compression in E (stretcher strain) forming process and tension interact, improve the circularity of welded tube, and reduce residual Residue stress.
It is of the invention to be with the different part of existing patent：
The disclosed methods that ERW is manufactured using double slit submerged arc of Chinese patent CN200710117991.1, it uses width Two blocks of steel plates for steel pipe girth 1/2 are spent, two blocks of steel plates is carried out first using double-submerged arc method and is spliced along longitudinal edge, then Taking conventional longitudinal submerged arc welded pipe production technology carries out steel pipe manufacturing.Or two blocks of steel plates are carried out into C shapings respectively, it is made C-shaped semicanal.Two C-shaped semicanal groups are welded into O shape pipes to positioning, the welding of twice weld seam is then carried out.By expanding, lossless Detection, completes the double-seam submerged-arc welding pipe making of oil, natural gas transportation, and the manufacture difficulty of tubulation sheet material is reduced so as to play, raw Produce the superior in quality steel pipe of heavy caliber and wall thickness.The present invention is straight using C, U, O, E moulding process and single seam on pipe-making method Seam submerged arc soldering method is welded, and there is significant difference on tube-making process with the patent.
Chinese patent CN100398684 provides a kind of made straight-line joint submerged arc welding tube of X120 pipe line steels and its manufacturing process, its The X120 steel plates of high intensity are manufactured using the design of microalloying ingredient containing B and controlled rolling process, through milling side, pre-bending, JCO shapings, pre- The operation systems such as weldering, interior weldering, outside weld, expanding, chamfered edge are in straight-line joint submerged arc welding tube.The present invention using without B composition design method and TMCP techniques have manufactured the steel plate with some strength and toughness, and carry out welded tube manufacture using UOE techniques, and the welded tube of manufacture is bent Take intensity and reach 625MPa and intensity higher and excellent impact flexibility；Have relative to JCOE moulding process simultaneously more excellent Ovality and residual stress distribution.
Japan Patent JP61099660A describes a kind of high corrosion-resistant welded tube and its manufacture method.By using low C, height Cr (18~25%), Ni high (27~40%) composition design can obtain high corrosion-resistant welded tube steel plate, and can be used for welded tube system Make.The present invention manufactures high intensity and ductility steel plate using the composition design method and cooling controlling and rolling controlling process of low C microalloys, Cr, Ni content are far below the lower limit of the patent, while carrying out welded tube manufacture using UOE techniques..
Chinese patent ZL200710185350.X discloses a kind of manufacture method of X100 straight-line joint submerged arc welding tubes, micro- using low-carbon (LC) The sheet stock of alloying, the ERW manufactured by JCO molding procedures has the mechanical characteristics of high-intensity high-tenacity.This Invention uses UOE tube-making processes, can obtain more excellent cast quality and residual stress distribution, is conducive to subsequent construction and weldering Connect.Existing with the patent has larger difference on molding mode.
Chinese patent ZL201010112123.6 discloses a kind of manufacture method of X100 spiral submerged welded pipes, and it uses low The sheet stock of carbon microalloy, by continuous helical shaping and spiral submerged arc welded technique, the welded tube of manufacture has high intensity The mechanical characteristics of high tenacity, patent main sides weight tube-making process technology, the composition design of sheet stock is mainly using higher The composition design method of Mn.The present invention uses UOE tube-making processes, can obtain more excellent cast quality and residual stress distribution, Be conducive to subsequent construction and welding.There is larger difference on raw material pattern, shaping and welding manner with the patent.
Chinese patent CN200780024813.2 proposes a kind of present invention and provides what a kind of toughness of the HAZ of steel pipe was reduced The line-pipes high tensile steel tube and its manufacture method of excellent in low temperature toughness, also provide the base as line-pipes high tensile steel tube The line-pipes high-strength steel sheet and its manufacture method of material.The elements such as Cu, Ni, Cr are not added with composition design, and not to N, O Content is limited.The present invention employs Cu, Ni, Cr alloying in composition design, while being limited the upper limit of N, O System；And welded tube manufacture is carried out using UOE tube-making processes, and more excellent cast quality and residual stress distribution can be obtained, be conducive to Subsequent construction and welding.There is larger difference in composition design and tubulation mode with the patent.
Chinese patent CN200480037950.6 provides a kind of high-strength thick line pipe welding of excellent in low temperature toughness Steel pipe and its manufacture method, mother metal steel plate is configured to be welded after tubulose, and the metal structure of mother metal steel plate includes 20% Following polygonal ferrite and more than 80% bainite, effective crystal particle diameter are less than 20 μm, while welding hot shadow can be made The effective crystal particle diameter for ringing area is less than 150 μm.Former material microscopic structure of the present invention is mainly full bainite microscopic structure；And use UOE tube-making processes carry out welded tube manufacture, can obtain more excellent cast quality and residual stress distribution.With the patent at micro- group Knitting in design and tubulation mode has larger difference.
Chinese patent CN200710185346.3 discloses a kind of manufacturer of X80 pipe line steels JCOE straight-line joint submerged arc welding tubes Method, it is applied to manufacture the transfer pipeline of high-intensity high-tenacity petroleum gas.The method includes that using chemical composition be C 0.03~0.05%, Si 0.20~0.30%, Mn 1.65~1.75%, P≤0.01%, S≤0.005%, Nb+Ti0.10~ 0.15%th, the HTP X80 controlled rolling steel plates of Ni+Cr+Cu 0.5~0.7%；" JCO " that steel plate is depressed through milling side, crimp, multi-pass Moulding process, gas shield prewelding, interior weldering, outside weld, expanding, ultrasonic examination, X-ray examination, the water pressure test, pipe end to rib, The operations such as ultrasonic examination, X-ray examination are manufactured into the petroleum gas delivering pipe of high-intensity high-tenacity.The interior outside weld of steel pipe is adopted With four tandem Lincoln welds, and welding wire, the solder flux being adapted to by selection, welding condition is controlled, so as to control weld seam Composition, tissue, make weld seam performance reach X80 performance requirements.The present invention uses the composition of Mn and Nb+V ＜ 1.0% higher Design, while using UOE tube-making processes, can obtain more excellent cast quality and residual stress distribution, is conducive to subsequent construction And welding.This exists on composition design, molding mode and has larger difference with contrast.
United States Patent (USP) US6464802 proposes a kind of manufacture method of Cr line pipes high, by the low C of use≤0.02%, The composition design scheme of≤0.3%Nb and 10%~14% Cr high, to improve heat affected area toughness and hot-working character, belongs to not Rust steel series tube product.It is entirely different product type with the low C alloy steel pipe of high intensity proposed by the present invention.
Japan Patent JP63250418A proposes a kind of manufacture method of high-strength low-yield ratio seamless line pipe, its into Set up meter composition based on C-Mn separately, add appropriate Nb microalloyings, by direct cooling to room temperature after hot rolling, and~ Cooling rate in 600 DEG C of temperature ranges is 5~30 DEG C/s, can obtain the seamless line pipe of yield tensile ratio≤0.85%.Steel of the present invention Plate is manufactured using microalloying ingredient method for designing and cooling controlling and rolling controlling process, and carries out vertical masonry joint submerged arc using UOE techniques Welded tube is manufactured.Compared with the patent, there is larger difference in composition design and tubulation mode.
The present invention has following features：
(1) using the design of low C microalloying ingredients and the design of lower bainite microscopic structure, effective particle size exists the present invention 3 μm and less, to obtain high intensity, low-temperature impact toughness high and good anti-dynamic tear performance；
(2) relatively low Alloying Design is used, by the rolling strengthened and cooling technique, is reduced while performance is ensured Production cost；
(3) designed using low S, low P, to ensure that exploitation steel has excellent degree of purity, improve low-temperature impact toughness；
(4) in cooling technique control, using strong cold+weak cold (DQ+ACC) technique, to obtain required phase-change organization's class Type, while playing a part of to improve template；
(5) present invention is molded using C, U, O, E moulding process, and is welded using suitable technique, is realized excellent Different mechanical property and cast Accuracy Matching.
Compared with existing production steel pipe, UOE welded tubes performance of the invention reaches claimed below：
Tensile property：Yield strength Rp0.2 >=625MPa, tensile strength Rm >=700MPa；Elongation percentage A50.8>=15%；- 20 DEG C of ballistic works：AKv≥230J；- 20 DEG C of DWTT (Drop Weight TearTest, drop weight tearing test) performances：SA% >= 85%.
Brief description of the drawings
Fig. 1 is the typical microstructures of embodiment of the present invention steel.
Specific embodiment
With reference to embodiment and accompanying drawing, the present invention will be further described.
Required according to steel chemical analysis of the present invention, the chemical composition of design embodiments, as shown in table 1.Table 2 is real for the present invention Apply example rolling and tube-making process path.By above-mentioned composition and technological design, the mechanical property that each embodiment is obtained is as shown in table 3.
It can be seen that, composition and technique, are all up target performance requirement designed according to this invention, with good resultant force Performance is learned, and carbon equivalent is relatively low, is conducive to improving steel pipe forming welding and site girth welding welding performance.Other present component letter Single, process window is wider, with stronger manufacturability.
For 625MPa grade super strength UOE welded tubes, natural-gas transfer pipeline construction is can be applied to, it is also possible to which Yu Haiyang is put down Platform and other structural members are built.For long distance pipeline construction, 625MPa grade super strengths welded tube can not only be reduced uses steel Amount, while discharge pressure can be improved, is conducive to the conveying capacity of riser tubing；For structural member application, can equally reduce Steel using amount, while having bearing capacity higher, it is adaptable to which larger equipment is built.Additionally, the 625MPa grades of fierce pipe of superelevation In the application in offshore platform structure part and pipe-line field, meet the demand of world's low-carbon economy and sustainable development, Have a good application prospect.

Claims (7)

1. a kind of 625MPa grades of UOE welded tube, its chemical component weight percentage is C：0.015~0.080%, Si：0.1~ 0.5%th, Mn：1.40~2.20%, P≤0.015%, S≤0.003%, Nb：0.03~0.10%, Ti：0.01~0.035%, Cu+Ni：0.20~0.50%, and Cu/Ni：1~2, Cr+Mo：0.3~0.6%, Ca：0.001~0.005%, Al：0.02~ 0.045%, N≤0.010%, O≤0.008%, remaining is Fe and is inevitably mingled with.
2. the manufacture method of 625MPa grades of UOE welded tube as claimed in claim 1, it is characterized in that, comprise the following steps：
1) continuous casting is smelted
Composition as described in claim 1 is smelted, and through smelting-LF+RH external refinings-continuous casting, obtains 200~300mm finger gauges The continuous casting steel billet of lattice；
2) heat：1070~1200 DEG C of slab reheating temperature；
3) roughing：It is >=960 DEG C that roughing stops temperature；Middle base is thick：Middle base thickness 4t~8t, t are final finished thickness, mm；
4) finish rolling：Finishing temperature is 730~820 DEG C；
5) DQ direct quenchings cooling：Final cooling temperature is 350~450 DEG C, cooldown rate >=30 DEG C/s；
6) ACC is quickly cooled down：Final cooling temperature is 80~350 DEG C, cooldown rate >=15 DEG C/s；
7) steel pipe forming welding, including steel pipe forming-UO shapings, steel-pipe welding；O forming compression ratio is 0.18~0.22%, its In, during O forming compression ratio=(π × (pre- postwelding external diameter-wall thickness)-milling width after)/milling after width × 100%；
8) expanding i.e. E shapings：Steel pipe total length after welding is carried out it is expanding, to meet the final tube type requirements of steel pipe, enlarging rate Scope is 0.8%~1.2%,
Wherein, enlarging rate=(expanding rear outer diameter of steel pipes-expanding preceding outer diameter of steel pipes)/expanding preceding outer diameter of steel pipes × 100%.
3. the manufacture method of 625MPa grades of UOE welded tube as claimed in claim 2, it is characterized in that, step 7) steel pipe forming welding Welding preparation, including：
1) striking plate weld：In four corner welding striking steel plates of steel plate, it is mainly used in striking effect during welding；
2) milling side, groove size：By divided edge of steel plate size design.
4. the manufacture method of 625MPa grades of UOE welded tube as claimed in claim 2, it is characterized in that, step 7) steel pipe forming welding Middle welded tube forming, including,
1) C shapings：Also known as crimp shaping, on crimp forming machine, needed for the edge of steel plate is bent to by beader Shape, it is ensured that the straight section of edges of boards is minimum during O forming；
2) forming U shaped articles：On forming U shaped articles machine, by the steel plate of pre-flanging through being once pressed into " U " type；
3) O forming：On O forming machine, by the steel plate after forming U shaped articles through being once pressed into " O " type；
4) high pressure water washing and drying：High pressure water washing will be carried out to weld the surfaces externally and internally of the steel pipe that cracks after shaping, go deoxygenation Change the pollution such as iron sheet, grease, dust；Entering drying oven after the completion of flushing immediately carries out drying and processing, and drying temperature is 100 DEG C~ 300℃。
5. the manufacture method of 625MPa grades of UOE welded tube as claimed in claim 2, it is characterized in that, step 7) steel pipe forming welding Middle steel-pipe welding, including：
1) prewelding：The steel pipe that cracks after to O forming, makes its opposite side Accurate align, positioning, and use CO2Or Ar+CO2Protection weld into Row continuous prewelding welding, to ensure in follow-up arc stability during weldering, outside weld, it is ensured that final welding quality；
2) weldering in：
For 10.0~15.0mm wall thickness specifications welded tubes, carry out welding welding in steel pipe using three submerged welding processes, the 1st is straight Stream reversal connection, the 2nd, 3 is exchange, and gage of wire is 3.5~4.5mm；1st electric current is 550~650A, and voltage is 22~30V； 2nd, 3 electric currents are 450~600A, and voltage is 30~40V；
For 15.1~20.0mm wall thickness specifications welded tubes, using four submerged welding processes, the 1st electric current is DC reverse connection, the 2nd, 3rd, 4 is exchange, and gage of wire is 3.5~4.5mm；1st be DC reverse connection, electric current be 1100~1200A, voltage be 28~ 40V；2nd~4 electric current is 500~700A, voltage is 34~42V；
Speed of welding is 1.5~1.9m/min；Interior weldering solder flux is both needed to be dried in the range of 250~450 DEG C, drying time >=2 hours；
3) outside weld：
For 10.0~15.0mm wall thickness specifications welded tubes, steel pipe outside weld welding is carried out using three submerged welding processes, the 1st is straight Stream reversal connection, the 2nd, 3 is exchange, and gage of wire is 3.5~4.5mm；
1st electric current is 850~1000A, and voltage is 30~40V；2nd, 3 electric currents are 450~650A, and voltage is 35~45V；
For 15.1~20.0mm wall thickness specifications welded tubes, using four submerged welding processes, the 1st electric current is DC reverse connection, the 2nd, 3rd, 4 is exchange, and gage of wire is 3.5~4.5mm；1st electric current is 1100~1200A, and voltage is 28~40V；2nd~4 Silk electric current is 500~700A, voltage is 34~42V；
Speed of welding is 1.3~1.8m/min；Outer-welding welding flux is both needed to be dried in the range of 250~450 DEG C, drying time >=2 hours.
6. the manufacture method of 625MPa grades of UOE welded tube as claimed in claim 2, it is characterized in that, seam inspection after welding, bag Include,
Welding line ultrasonic is detected a flaw：Using ultrasonic detection method, detection postwelding crackle, layering, lack of penetration weld defect；
Weld seam x-ray inspection：Using x-ray inspection method, detect postwelding bubble, be mingled with point-like weld defect.
7. the manufacture method of 625MPa grades of UOE welded tube as claimed in claim 2, it is characterized in that, step 8) it is expanding after include such as Lower step：
8) welding line ultrasonic flaw detection：Using ultrasonic detection method, expanding rear crackle, layering, lack of penetration weld defect are detected；
9) weld seam X-ray examination：Using x-ray inspection method, detect expanding rear bubble, be mingled with point-like weld defect；
10) chamfered edge：Steel pipe two ends are carried out with tack, chamfered edge treatment, is that job site butt welding offers convenience；
11) pipe end layering ultrasonic inspection：Ultrasonic flaw detection test is carried out to the steel tube end part after chamfered edge, lamination defect is prevented；
12) pipe end magnetic powder inspection：Magnetic powder detection is carried out to the steel tube end part after chamfered edge, lamination defect is prevented；
13) protection ring on：Pipe end is protected, it is ensured that the butt welding quality during steel pipe site operation.
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