The big wall thickness straight-line joint submerged arc welding tube of super large caliber manufacture method
The present invention relates to straight-line joint submerged arc welding tube manufacturing technology field.
Petroleum gas is as important energy source, and ratio shared in China's energy resource structure constantly increases, and demand is vigorous day by day.Utilizing long distance line that petroleum gas is transported to customer objective ground from the grown place, is a kind of safe, efficient and economic means of transportation, and this has become the main mode that land oil gas is carried at present.
The grade of steel of China's natural gas main pipeline is brought up to X80 by X52, the wall thickness of one-level area caliber φ 1219mm gas trunklines pipeline has reached 22mm, year displacement is 300 billion cubic meters, if the year displacement will be brought up to more than 450 billion cubic meters, main technological route has two: (1) adopts the technology path that improves discharge pressure, requires to bring up to more than the 17MPa from existing 12MPa discharge pressure.(2) adopt the technology path that increases the conveyance conduit bore, require to bring up to 1422 from existing 1219.
The world has several at the pipeline of the 45000000000 m3/a displacements of building and planning to build at present, as Muscovite Ba Funiankewo-Wuqia natural gas line, adopt the K65 grade of steel that is similar to X80, caliber φ 1420mm, discharge pressure 11.8MPa, about 50,000,000,000 m3/a of mono-tube design displacement.In addition, the pipeline of similar displacement is also being established in the North America, and as seen, the The Enlargement Tendency of welded tube bore is obvious.
The direct influence that the increase of caliber and pressure brings is the increase of thickness of steel pipe.The increase of thickness of steel pipe will bring difficulty to moulding, the welding of the rolling and steel pipe of steel plate.Therefore, make the big wall thickness straight-line joint submerged arc welding tube of super large caliber and also have certain defective technically.
Summary of the invention
The technical problem to be solved in the present invention provides the big wall thickness straight-line joint submerged arc welding tube of the super large caliber manufacture method that a kind of every performance meets standard-required fully.
For solving the problems of the technologies described above, the technical solution used in the present invention is:
The big wall thickness straight-line joint submerged arc welding tube of a kind of super large caliber manufacture method, it adopts chemical composition percentage to meet the API 5L-2007 of American Petroleum Institute (44 editions) standard, microscopic structure is the X80 hot-rolled state steel plate manufacturing of AF+B tissue, and its manufacturing process comprises the steps: steel plate automatic flaw detection, groove processing, pre-bending, moulding, prewelding, interior outside weld, ultrasonic wave automatic inspection for the first time, X-ray examination for the first time, machinery expanding, pipe end processing, the water pressure test, groove processing, ultrasonic examination for the second time, X-ray examination for the second time, pipe end ultrasonic manual examination (check) for the second time, appearance and dimension check, post weld heat treatment, visual examination and corrosion-inhibiting coating;
In the described groove manufacturing procedure, the steel plate angle of groove up and down is 34.75 °～35 °, and last groove depth is 10.75～11.25mm; The width of root face is 9.075mm～9.125mm, and angle is 4 °;
Described inside and outside welder's preface all adopts four Lincoln welds that steel pipe inboard and outside bevel for welding are welded, and gage of wire is 3.9～4.1mm, and speed of welding is 1.3～1.35m/min; Weld heat input is 55～56KJ/cm.
Described molding procedure adopts the JCO moulding, at first utilize the JCO make-up machine to carry out repeatedly punching press through half of the steel plate behind the pre-crimp, be pressed into " J " shape, then second half of steel plate carried out same repeatedly punching press, be pressed into " C " shape, the middle pressing one-time at whole steel plate makes it form " O " shape of opening at last; In the above-mentioned Sheet Metal Forming Technology, adopt the compacting number of times in 25～29 steps, single drafts 180～190mm.
Described inside and outside welder's preface all adopts four Lincoln welds that steel pipe inboard and outside bevel for welding are welded; First is dc reverse connection, electric current 1050～1150A, voltage 30～34V; Second for exchanging electric current 850～950A, voltage 32～36V; The 3rd for exchanging electric current 650～750A, voltage 38～42V; The 4th for exchanging electric current 550～650A, voltage 38～42V.
In the described machinery expanding operation steel pipe total length is carried out 0.5%～1.2% hole enlargement.
Beneficial effect of the present invention is as follows:
(1) by composition, tissue and heat treated control, make steel plate have high tenacity and good welding performance to the X80 steel plate.
(2) by in the JCO moulding process, according to steel plate width, thickness, intensity and die size, Accurate Analysis is determined rational punching press number of times and single drafts, the big wall thickness straight-line joint submerged arc welding tube of the super large caliber JCO forming process light plate resilience that has solved X80 grade of steel diameter and be φ 1422mm, wall thickness and be 30.8mm is little, a tubular difficult problem that is not easy to control, according to analysis result and field trial, analyze steel plate forming process spring-go amount, rationally determine draught per pass, make to have good circularity after the steel pipe moulding and body is directly spent.
(3) in the welding procedure, at first, guarantee that weld seam has the intensity of a little higher than mother metal and good toughness by selecting the special welding material.When determining welding parameter; take into full account in three wire bonds effect of each; by each electric current of reasonable setting, voltage, angle, distance between weldingwires and speed of welding, make weld seam obtain suitable depth of penetration and good shapes, help gas and covering slag come-up in the welding process simultaneously.On this basis,, each current/voltage is further optimized, taked lower welding wire energy, guarantee the performance of welding heat affected zone in order to reduce the influence of sweating heat to heat affected area toughness.Weld seam finally obtains based on tissue acicular ferrite and ferrite bainite, that have excellent toughness, and welding heat affected zone obtains the tissue of tiny granular bainite and ferrite bainite simultaneously, has solved Steel Welded Joint toughness problem.
(4) in the expanding technology, according to the apparent size situation after the steel pipe moulding, determine to obtain the enlarging rate of optimum efficiency by numerical analysis, verify again by field trial with to the result of correlated performance data analysis, determine best expanding technology, guarantee that apparent size and physicochemical property meet standard-required behind the pipe expanding, solved steel pipe when machinery expanding because the problem that work hardening causes intensity increase, toughness and uniform elongation to reduce, important appearance index such as also improved that pipe end circularity and body are directly spent simultaneously.
The specific embodiment
Employing chemical composition percentage meets the API 5L-2007 of American Petroleum Institute (44 editions) standard, microscopic structure is the X80 hot-rolled state steel plate of AF+B tissue, carrying out caliber is that 1422mm, wall thickness are the manufacturing of the straight-line joint submerged arc welding tube of 30.8mm, and concrete processing step is as follows:
(1) ultrasonic wave steel plate automatic flaw detection: utilize full-automatic steel plate ultrasonic test equipment, in the edges of boards 50mm scope of steel plate both sides and middle part is checked.
(2) mill limit, groove processing: the bevel angle up and down of steel plate is 35 °, and the width of root face is 9.1mm.The purpose of finished edge is to guarantee that welding process can complete penetration, forms suitable weld seam pattern, avoids occurring defectives such as lack of penetration in the high-speed welding process, guarantees the quality of welding point, the realization good quality and high output.Choose steel plate according to steel pipe intended diameter and thickness, and at the steel plate both sides milling bevel for welding of weld seam correspondence.
(3) pre-bending: require and the caliber size requirement according to steel pipe curvature, adopt pre-joggling machine that edges of boards are bent to satisfactory curvature.
(4) JCO moulding: adopting caliber is that φ 1422mm, wall thickness are the steel pipe of 30.8mm, at first utilize the JCO make-up machine to carry out repeatedly punching press through half of the steel plate behind the pre-crimp, be pressed into " J " shape, carry out same repeatedly punching press again with its second half, be pressed into " C " shape, the middle pressing one-time at whole steel plate makes it form " O " shape of opening at last; In the above-mentioned Sheet Metal Forming Technology, adopt the compacting number of times in 27 steps, single drafts 185mm.
(5) prewelding: by adjusting the position of joint close Prewelding machine pressure roller; make the bevel for welding of steel pipe is good after the moulding coupling together; guarantee that misalignment, gap size meet the requirements; adopt gas shield welding mode to weld simultaneously; form continuously, standard, stay-in-grade pre-welding line, guarantee inside and outside steel pipe welding operating mode stable when astute and able.
(6) interior outside weld: adopt four Lincoln welds to weld in steel pipe inboard and outside bevel for welding; First is dc reverse connection, electric current 1100A, voltage 32V; Second for exchanging electric current 900A, voltage 34V; The 3rd for exchanging electric current 700A, voltage 40V; The 4th for exchanging electric current 600A, voltage 40V; Gage of wire is 4.0mm; Speed of welding is 1.3～1.35m/min; Weld heat input is 55～56KJ/cm.
(7) pipe end ultrasonic manual examination (check) for the first time: weld seam in the pipe end 300mm scope and weld seam two side areas are carried out manual ultrasonic examination;
(8) ultrasonic wave automatic inspection for the first time: steel pipe inner and outer welding and heat affected area, weld seam both sides part after the welding are carried out ultrasonic examination;
(9) X-ray examination for the first time: the steel pipe inner and outer welding after adopting image processing system to welding carries out 100% industrial television inspection, guarantees flaw detection sensitivity.
(10) machinery expanding: the steel pipe total length is carried out 0.5%～1.2% hole enlargement to improve the apparent size precision of steel pipe,, and improve the internal stress distribution of steel pipe as ovality, linearity.
(11) pipe end processing: the steel pipe end face is processed, guaranteed smooth.For the good seal of next step water pressure test is got ready.
(12) water pressure test: steel pipe is carried out 100% hydrostatic test, and test pressure is 90%～100% of the regulation SMYS, checks the strength level of steel pipe and whether has leakage point.
(13) groove processing: the above-mentioned steel pipe that is up to the standards is carried out pipe end processing, reach the pipe end groove dimensional requirement of customer requirement.
(14) ultrasonic examination for the second time: steel pipe inner and outer welding behind hole enlargement, the hydraulic pressure and heat affected area, weld seam both sides part are carried out 100% inspection, to get rid of hole enlargement, the issuable defective of hydraulic pressure.
(15) X-ray examination for the second time: the steel pipe inner and outer welding behind hole enlargement, the hydraulic pressure carried out 100% industrial television inspection and pipe end film making and check, to get rid of hole enlargement, the issuable defective of hydraulic pressure.
(16) pipe end ultrasonic manual examination (check) for the second time: the body in the pipe end 300mm scope, weld seam and heat affected area, weld seam both sides part, groove face are checked.
(17) appearance and dimension check: the shaping steel tube apparent size is measured according to designing requirement.
(18) post weld heat treatment: heat treatment parameter butt welded seam and heat affected area, weld seam both sides part according to design are heat-treated, and discharge welding interior stress.
(19) outward appearance is through looking into and corrosion-inhibiting coating: the steel pipe that heat treatment is finished carries out the pipe end ovality and body is directly spent inspection, and qualified steel pipe carries out coating and preservative treatment according to designing requirement to steel pipe inwall or outer wall.
In sum, the technology control by each operation strictness, every performance of final steel pipe is met fully every requirement of " natural-gas transfer pipeline with OD1422mm X80 straight-line joint submerged arc welding tube technical conditions exposure draft ".