Method of producing sleeves

FIELD: metallurgy.

SUBSTANCE: method comprises plugless reduction of the ingot of fixed length in three-roll breaking-down mill caliber formed by rolls deployed at the feed angle, and piercing of the reduced ingot in the piercing mill. After deformation of 0.75-0.85 length of the ingot, roll speed of breaking-down mill is reduced to a value corresponding to 15-50% of the roll speed atestablished process of ingot reduction. When reducing the ingot with length of more than one and a half of breaking-down mill roll body lengths, feed angle of breaking-down mill rolls is regulated by mathematical relationship. Reduction of the ingot with length of less than one and a half of breaking-down mill roll body lengths is carried out with a gradual regulated increase in the roll speed after its gripping.

EFFECT: improved quality of the end surface of the sleeves, reduced defects from the ring delamination on exterior and interior surfaces of tubes, increased durability of the rolling tool.

3 cl, 3 dwg, 5 tbl

 



 

Same patents:

FIELD: metallurgy.

SUBSTANCE: this process comprises making of ESR ingots and their turning to 490×2000±50 mm ingots-billets. Through central 100±5 mm diameter bore is drilled therein. Said ingots-billets are heated in continuous furnace to 1160-1170°C, pierced at helical rolling mill to 500xOD265×2440-2560 mm or 500xOD225×2180-2300 mm sleeves at 250 mm and 210 mm diameter mandrels with rolling-out µ = 1.25 and µ = 1.12 with increase in diameter δ = 2.04%. Said sleeves are rolled at PRU 8-16" with Pilger mills to commercial long 325×46×6700-7100 - 325×60×5400-5700 mm pipes with rolling-out of µ = 3.32 to µ = 2.98 and diameter reduction Δ = 34.0%. Sleeves are fed to deformation centre m = 22-26 mm, process wastes are cut off as seed ends and Pilger heads by hot cutting saw. Pipes are heat treated, etched and subjected to ultrasound control and acceptance with pipe diameter tolerance of +1.25/-1.0% and wall thickness tolerance of +20.0/-5.0%. Long pipes are produced to comply with requirements of Specs TU 14-3P-55-2001.

EFFECT: compliance with specifications.

1 tbl

FIELD: metallurgy.

SUBSTANCE: from alloy "ХН43БМТЮ-ИД" initially melting is performed in VI furnaces at temperature 1500-1520°C to produce consumable electrode, then vacuum-arc remelting of the consumable electrode is performed in VA furnaces to produce ingot of double vacuum melting, i.e. IA-ingot. Then hot deformation of IA-ingot is performed in horizontal press with pre-heating in ring heating furnace to produce intermediate billet ⌀ 95 mm, in semi-continuous medium/small schedule rod mill "350/250" the pipe billet ⌀ 65 mm is produced, it is turned at screw lathe to ⌀ 57 mm. Internal hole ⌀ 40 mm or ⌀ 51 mm is drilled through full length of the pipe billet producing shell. Drill rotation speed, drill longitudinal feed are specified, then shell is rolled by at least two passes using pipe cold roll mills CPR-55 and CPRR 30-60 or at least by four passes using mills CPR-55, KPW-50 and CPR-30. The heat-resistant seamless pipe has hollow profile of permanent cross-section of off-gage length of specified size, and is made out of alloy "ХН43БМТЮ-ИД" with specified composition.

EFFECT: possibility to prevent cracks, blisters, folds.

18 cl

FIELD: metallurgy.

SUBSTANCE: method includes blanks and ingots-blanks of electroslag melting heating to plasticity temperature, blanks and ingots-blanks of electroslag melting piercing to shell-blanks, shell-blanks heating from cold or hot charging to plasticity temperature, shell-blanks piercing-rolling to shells in barrel-shape rollers having input and output cones and cylindrical part with screw thread. The input cone contains a guide cone and piercing cone in form of a cone of initial and secondary clamping with angles 3° and 10°, respectively, and output cone contains reeling mandrel with angle 6°, cylindrical part and cone part of shell exit from rollers with angle 3°. Piercing-rolling is performed in rollers, which length of screw thread LT of the cylindrical part is determined by the mathematical expression.

EFFECT: increased accuracy of shells wall, reduced metal consumption coefficient.

1 tbl

FIELD: machine building.

SUBSTANCE: guide bar includes input and output sections with a ridge in-between. A sleeve with minimal change of the diameter and wall thickness with straight-line front end is produced due to the fact that the guide bar is fitted with a conical channelled recess after the ridge with the radius being equal to 0.52-0.75 of the current distance between the rollers. The guide bar provides for narrower gauge in the zone of its output part.

EFFECT: no profile distortion and filling of gap between the rollers and guide bars by metal.

3 dwg

FIELD: technological processes.

SUBSTANCE: invention relates to pipe rolling. Hollow bars of electroslag melting are turned and ground into hollow blooms with size of 500×vn.320×3200±50 mm. Blooms are heated to temperature 1180-1200°C and rolled on a TPU 8-16" pilger mills into pig pipes with size of 325×15×21500-22300 with drawing m=7.78, clamping by diameter 36.2% and with supply of hollow blooms into a deformation site m=15-18 mm. Technical wastes are cut - seed ends and pilger heads of hot cutting. Pipes are cut, straightened on a six-roll melting machine, thermally processed. Acceptance is carried out with allowance by diameter of +1.25/-1.0 and wall thickness of ±12.5%. Pig pipes with size of 325×15×7170-7430 mm are rolled on a cold-pilgering mill 450 into commercial cold-rolled pipes with size of 299×10×11100-11500, 299×11×10150-10500, 299×12×9300-9600 and 299×13×8600-8900 mm with drawing of accordingly m=1.61, m=1.47, m=1.35 and m=1.25.

EFFECT: reduced discharge coefficient of metal.

2 cl, 1 tbl

FIELD: technological processes.

SUBSTANCE: invention relates to tube rolling. Hollow ingots with the ratio of diameter to wall thickness of 5.0 to 5.5 are molten by means of an ESR method, which are then turned and bored into hollow cakes with the ratio of diameter to wall thickness of 5.8 to 6.6. Cakes are heated to the temperature of 1190-1200°C and rolled on TPU 8-16" unit with pilger mills into semi-finished tubes with the size of 480×30-35 mm with supplies to deformation zone m=14-16 mm and semi-finished tubes with the size of 480×38-40 mm with supplies to deformation zone m=15-17 mm. Semi-finished hot-rolled tubes are straightened, heat treated, turned and bored into marketable tubes.

EFFECT: improvement of mechanical properties and accuracy of geometrical dimensions of tubes.

1 tbl

FIELD: metallurgy.

SUBSTANCE: hollow ingots of electroslag remelting are turned and bored into hollow cakes with the size of 660xin490×3200±50 mm. They are heated to the temperature of 1180-1190°C and rolled on TPU 8-16" pipe rolling units with pilger mills into process pipes with the size of 550×45×5300-5500 and 550×48×5000-5200 mm with drawings µ=2.10, µ=1.99 respectively and by setting as to diameter of 16.7%, with supplies of shells to deformation zone m=20-22 mm. Cutting of process wastes by a hot cutting saw, straightening on a six-roll straightening machine, heat treatment, repeated straightening on the six-roll straightening machine with measurement of overall curvature throughout the length of pipes of not more than 5.0 mm is performed. Pipes are transported to an area for treatment of forgings and pipes of special purpose. Pipes with the size of 550×45×5500-5800 mm are bored and turned into merchantable pipes with the size of 530×25-28×5300-5500 mm. Pipes with the size of 550×48×5000-5200 mm are bored into merchantable pipes with the size of 530×28-30×5000-5200 mm.

EFFECT: reduction of metal consumption coefficient and increase of capacity of a pilger unit.

2 cl, 1 tbl

FIELD: process engineering.

SUBSTANCE: invention relates to pipe rolling. Hollow ingots-billets sized to 680×Din.×3300 mm are cast by ESR process, the inner ID Din is defined by mathematical relationships. Hollow ingots-billets are machined to billets. Billets are heated in the furnace to ductility temperature and rolled at Pilger mills at rolls with body diameter of 1150 mm. Note here that pipes with D/S≥20 ratio are rolled with grinding factor of 3.0-3.5, while pipes with D/S≤20 factor are rolled with grinding factor of 2.5-3.0. Scale from inner surface of ingots-billets is removed by blowing after their discharge from the furnace.

EFFECT: lower power and metal input and costs, higher efficiency.

1 tbl

FIELD: metallurgy.

SUBSTANCE: hollow electroslag remelting cakes are heated to ductility temperature and rolled on a pilger mill. Rolling is performed in rolls with a body diameter of 1150 mm so that tubes with dimensions of 610×32-90 or 630×28-80 mm are obtained. Difference between inner diameter of a hollow cake and diameter of a mandrel at tube rolling with the ratio of diameter to thickness of the wall of D/S≥18 is assumed as equal to 10-15 mm, and at D/S≤18 ratio it is equal to 15-20 mm. Tube rolling with D/S≥15 ratio is performed using a polishing coefficient of 3.0-3.5, and for tubes with D/S≤15 ratio -with polishing coefficient of 2.5-3.0.

EFFECT: reducing transverse and longitudinal thickness variation and reducing metal consumption coefficient.

2 cl, 1 tbl

FIELD: process engineering.

SUBSTANCE: invention relates to pipe rolling. This process comprises casting of hollow ESR ingots, turning them and boring to 640×ID.440×3200±50 size hollow ingots-billets. The latter are heated to 1190-1200°C and rolled at PRU 8-16" with Pilger mills to rerolled 465×22×14100-14600 and 465×25×12200-12600 mm pipes with rolling-out µ=5.43 and µ=4.81, respectively, diameter reduction of 27.3% and with feed of sleeves to the source of strain m=15-17 mm. Seed ends and pilger heads are cut off rerolled pipes and straightened at six-roll straightener. Rerolled pipes are machined, cut to two equal lengths and rolled at "ХПТ" 450 mill to commercial pipes. Rerolled 465×22×7050-7300 mm pipes are rolled to commercial cold-rolled 426×15×10200-10500, 426×16×9500-9900 and 426×17×9000-9400 mm pipes with rolling-put µ=1.50, µ=1.41 and µ=1.34, respectively. Rerolled 465×25×6100-6300 mm pipes are rolled to commercial 426×18×8350-8600, 426×19×7900-8200 and 426×20×7600-7800 mm pipes.

EFFECT: higher surface quality and precision of geometrical sizes, lower metal input.

2 cl, 1 tbl

FIELD: tube production, namely processes for piercing in helical rolling mills.

SUBSTANCE: method for piercing ingot-blanks in helical rolling mills comprises steps of biting ingot-blank by means of rolls; intensively deforming wall on mandrel and rolling out hollow body having no inner rigid support; again rolling out hollow body of sleeve in deformation zone restricted by means of cantilever portions of rolling rolls.

EFFECT: elimination of sleeve curvature, lowered wall thickness difference of sleeve.

FIELD: processes for making seamless tubes, namely with use of screw rolling equipment.

SUBSTANCE: method comprises steps of reducing heated blank in three-roll pass formed by rolls turned by feed angle and having reduction portion; piercing blank in pass formed by mandrel, guiding tool and two rolls turned by feed angle and having piercing portions; reducing blank in three-roll pass at feed angle of rolls consisting 1.4 - 4.0, at inclination angle of generatrix of reduction portion relative to rolling axis consisting 1.3 - 5.6, and at percentage reduction value consisting 1.6 - 6.2 respectively of feed angle, inclination angle of generatrix of roll piercing portion to rolling axis and percentage reduction value before nose of mandrel during piercing process.

EFFECT: lowered quantity of technological waste caused by occurring of inner and outer films, improved accuracy of sleeves made by screw rolling, mainly of continuously cast billets.

1 tbl, 3 ex

FIELD: rolled stock production, plastic working of metals, namely helical piercing processes.

SUBSTANCE: method comprises steps of guiding heated billet to working rolls turned by angle of feeding and expansion; piercing billet by means of plug mounted in pass formed by rolls and guiding tool. Feed angle value is in range 12 - 18°; expansion angle value is in range 6 - 10°. Reduction degree in restriction portion is in range 21 -35 % and it is realized with use of rolls having inlet cone angle equal to 4 -8°. Reduction degree of billet in front of nose of plug is normalized by means of mathematical expression given in description of invention.

EFFECT: possibility for making tubes with high accuracy geometry size and high quality inner and outer surfaces.

1 dwg, 1 ex

FIELD: mills for rolling seamless tubes, namely steel seamless tubes.

SUBSTANCE: rolling mill includes predetermined number of rolls deforming outer periphery of tube or its blank and internal tool in the form of mandrel arranged coaxially relative to tube or its blank. Deformation range is created between rolls and said internal tool. Rolls and tool are suitable successively piercing tube blank and for elongating it tube. Rolls have in their both end zones at least one portion for gripping and transporting tube or its blank. Internal tool has in its axial end zone portion for piercing tube blank and cylindrical portion adjacent to said piercing portion and used for elongating tube.

EFFECT: possibility for performing combination process of piercing tube blank and elongating tube.

11 cl, 2 dwg

FIELD: rolled tube production processes and equipment, namely manufacture of seamless hot deformed tubes in tube rolling aggregates with pilger mills.

SUBSTANCE: method comprises steps of heating ingots and billets till yielding temperature; piercing them to sleeves in screw rolling mills; rolling sleeves to tubes in pilger mills between rolls with periodic profile and with cross outlet angle 20-25° at tilting sleeve-tubes. In pilger mills tubes are rolled at tilting them by 70±2° or 110±2°.

EFFECT: enhanced quality of tubes due to lowered wall thickness difference, improved efficiency of pilger mills, reduced cost of ingot- tube conversion process.

1 dwg, 1 tbl

FIELD: processes for piercing large-diameter ingots in screw rolling mills, possibly manufacture of tubes in tube rolling aggregates with pilger mills.

SUBSTANCE: method for piercing ingots of large diameters of cold resistant kind of steels comprises steps of deforming solid part of ingot till nose of mandrel; deforming ingot onto mandrel and deforming it at rolling around sleeve. Deformation of ingot characterized by relation 3.1 ≤ L/D ≤ 3.6 in front of mandrel nose lowers linearly from bottom portion of ingot to its head from reduction degree 10% till 6% where L - ingot height, mm; D - diameter of bottom part of ingot, mm.

EFFECT: lowered inner scabs and spills at piercing large diameter ingots.

FIELD: rolled tube production, namely piercing sleeves of ingots having shrink holes and of drilled blanks of steel kinds with trend to occurring in back ends of sleeves so called "triangles", possibly manufacture of tubes in tube rolling plants with pilger mills.

SUBSTANCE: method comprises steps of deforming ingots and blanks on mandrel by means of working rolls, idle rollers and liners; moving axes of rollers in horizontal plane towards sleeve rotation beginning from time moment of mandrel approaching to shrink hole and load growing of mill drive. Deformation of ingots and blanks is realized in pass formed by working rolls, idle rollers or liners. Axes of rollers or liners are arranged stationary at shifting them in horizontal plane relative to piercing axis to side of sleeve rotation while in vertical plane shifting to piercing axis for rollers and from piercing axis for liners. Axes of idle rollers are shifted in horizontal plane relative to piercing axis to side of sleeve rotation by value L and in vertical plane to piercing axis by value Li. L = KDr + Ds/Ss; Li = K1 Dr +Ds/Ss, where Dr - diameter of idle roller on constricted portion, mm; Ds - outer diameter of sleeve, mm; Ss - sleeve wall thickness, mm; K = (0.2 - 0.3) - factor taking into account geometry size of sleeves for determining shifting value of idle roller axes in horizontal plane; K1 = (0.02 - 0.03) - factor taking into account geometry size of sleeves for determining value of shifting axes of idle rollers in vertical plane. Shifting value of liners axes in horizontal plane relative to piercing axis L2 = Ds/Ss and in vertical plane their shifting from piercing axis L3 = K2 x Ds/Ss, where K2 = (0.5 -1.0) - factor taking into account geometry size of sleeves for determining shifting value of liner axes in vertical plane. Large values of factors K, K1, K2 are set for sleeves with high relation Ds/Ss. Invention provides lowered metal consumption at rolling tubes in tube rolling plants with pilger mill from ingots with diameters 550 mm and more and from drilled blanks with diameter 600 mm and more.

EFFECT: improved quality of sleeves due to lowered number or complete elimination of "triangles" in end portions of thin-wall sleeves.

3 cl

FIELD: rolled tube production, namely piercing ingots and blanks of titanium base alloys, possibly production of conversion large- and mean-diameter tubes in tube rolling plants with pilger mills.

SUBSTANCE: method comprises steps of heating drilled blanks and ingots in muffles till yielding temperature; piercing them in skew rolling mill with use of short mandrel to sleeves at interim cooling of outer surface of ingots and blanks before piercing. Cooling down of ingots and blanks is realized at rotating them in air for time period t =0.45 Db where t - cooling down time period, s; Db - outer diameter of ingots and blanks, mm. Cooling down may be also realized with use of gaseous agent chemically neutral to titanium base alloys and fed onto surfaces of rotating ingots and blanks for time period t = 95xDbxC where Db - outer diameter of ingots and blanks, m; C - speed of gaseous chemically neutral agent, m/s. Revolution number of ingots and blanks is (2 - 5) rev/min. Gaseous agent is fed at speed (2 - 3) m/s.

EFFECT: elimination of slipping, jamming and distortions of blanks due to friction factor uniform along perimeter and length.

3 cl, 1 tbl

FIELD: tube production, namely method for piercing billets in helical rolling mills, possibly manufacture of tubes of steels with boron content up to 2% in tube rolling aggregates, for example with automatic mills.

SUBSTANCE: method comprises steps of heating billet till temperature 1050 - 1100°C; biting billet between rolls; reducing continuous portion of billet till nose of mandrel; intensively deforming billet on mandrel till roll constriction and rolling it out on outlet cones of rolls. Piercing is performed at reduction degree of billet no more than 12% in roll constriction at oval degree in deformation zone 1.08 -1.12 and at relation of reduction value in roll constriction to reduction value in front of mandrel nose 2.0 - 2.7. Quantity of feed strokes from beginning of billet biting till mandrel nose is set by roll feed angle in range 3 - 5.

EFFECT: possibility for piercing sleeves of boron containing steels without breaking them.

FIELD: rolled tube production, namely piercing ingots of large and mean diameters in helical rolling mills, possibly manufacture of tubes in tube rolling plants with pilger mills.

SUBSTANCE: method comprises steps of subjecting mandrel to mechanical vibration in axial direction at amplitude 2 - 4 mm and frequency providing cyclic separation of working surface of mandrel from metal. Said steps are realized when condition L/T < A x f is satisfied, where L - length of blank, mm; T - time period of piercing, s; A- oscillation amplitude, mm; f -oscillation frequency, 1/s.

EFFECT: enhanced quality of tubes rolled of cast ingots, lowered consumption factor of metal, reduced load of rolling mill drive unit.

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