RU2564505C2 - Production of seamless hot-rolled, smooth, threaded, boiler-room, thick-wall and special-purpose pipes 273-630 mm in diameter at pru with pilger mills - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to pipe rolling. Continuously-cast, forged billets, solid and hollow ESR 400-650 mm-sized ingots-billets are heated to ductility temperature. Threes are broached at helical rolling mills at short mandrel to sleeves or sleeve-blanks at one stand. Sleeves-billets are broached-rolled at short mandrel at second helical rolling mill without heating or after reheating. Sleeves are blown and transferred to Pilger mills. Sleeves are rolled in rolls with body diameter varying from 975 to 1250 mm with multiple 25 mm increase per every next diameter of the size spectrum pipes with gages of 280-562 mm at mandrels with taper of 1.0-6.0 mm subjected to the steel linear expansion factor. Pilger heads and seed ends, process wastes, are removed. Pipes are cut to multiple lengths by hot cutting saws and heated in continuous sectional furnaces or furnaces with walking beams. Pipes are gaged and carried on conveyors with rotation. Pipes are straightened in six-roll straightening machines, inspected and subjected to further machining.

EFFECT: lower metal input.

8 cl

Description

The invention relates to pipe rolling production, in particular to a method for the production of seamless pipes with a diameter of 273 to 630 mm in pipe rolling plants with pilgrim mills, and can be used on existing pipe rolling plants with pilgrim mills after their reconstruction, as well as on TPU with new generation piligrim mills whose technological process is controlled by a computer from the formation of a portfolio of orders to the shipment of finished products.

In the Russian pipe industry, methods are known for the production of seamless hot-rolled commodity smooth, threaded, boiler, thick-walled and special-purpose pipes with a diameter of 273, 299, 325, 340, 351, 377, 406, 426, 465, 508, 530, 550 mm with wall thicknesses from 8 to 90 mm and conversion pipes with a diameter of 273 to 550 mm with wall thicknesses of 25 to 75 mm, which are produced on a pipe rolling mill 8-16 ″ with pilgrim mills (GOST 8732 “Seamless steel tubes, hot deformed”, GOST 632-80 “Pipes casing pipes and couplings for them ", TU 14-3-1575-88" Casing pipes with outer diameter 351, 377 and 426 mm and their couplings ”, TU 14-ЗР-55-2001“ Seamless steel pipes for steam boilers and pipelines ”, TU 14-3-420-75“ Pipes for steam boilers and pipelines made of 15GS steel and 15X1M1F ", TU14-ЗР-197-2001" Conversion pipes from corrosion-resistant steel grades ", TU 14-3-1564" Conversion pipes from 08Kh10N20T2 and 08Kh10N16T2 steel for sliding systems ", etc.).

The disadvantages of these methods are: rolling pipes with a diameter of not more than 550 mm; rolling of pipes with a diameter of more than 426 mm in rolls with a barrel diameter of 1045 mm leads to a decrease in the polishing coefficient, which in turn leads to a decrease in the feed rate, a decrease in the performance of pilgrim mills, and an increased transverse and longitudinal difference; rolling of pipes at lower feeds leads to an increase in machine rolling time and, as a consequence, to a decrease in the temperature of the end of rolling, which, in turn, leads to increased loads on the drive of the pilgrim mill, increased longitudinal and lateral difference, increased rejection and increased consumption coefficient of metal ; rolling of pipes with a diameter of more than 426 mm in rolls with a barrel diameter of 1045 mm is possible only with a ratio of D / S≤23; according to this method, each pipe diameter requires its own diameter of the workpiece or ingot, which for rolling pipes with a diameter of 630 mm must be at least 750 mm; at the moment, billets produced at continuous steel casting plants do not exceed 600 mm, because as the diameter increases, the quality indicators of the workpieces decrease and the metal and energy consumption of the plants increase; rolling of pipes on conical mandrels leads to longitudinal difference, and rolling on cylindrical mandrels to their sunset in tube sleeves, i.e. to marriage, to eliminate this drawback, it is necessary to carry out the process of rolling the lash tubes with a smooth rise of the upper roll for each feed of the sleeve into the deformation zone, which can only be done automatically under computer control; cutting lash pipes to measured lengths with impact saws on a pilgrim mill is not possible, and cutting to multiple lengths leads to additional end waste due to crushing, uneven heating before calibration, which leads to deviations of the end sections in diameter, crushing of the end sections to the dressing process and additional waste when removing defects after the initial inspection.

The closest technical solution is the method of flashing blanks and ingots-blanks of ESR using two transverse helical rolling mills located in parallel in the production line in the process stream, the output side of the first cross-helical rolling mill is located at the input side of the second mill and is equipped with a transfer grill. Cross-screw rolling mills have individual transport roller tables from furnaces for heating blanks and ingots-blanks ESR to the input sides of the mills and individual transfer trolleys from their output sides to the pilgrim mills (Patent RU No. 2387496, class B21B 21/00, 10/27/2010 Bulletin No. 12).

The advantages of this technological scheme are that it makes it possible to produce pipes with a diameter of 426 to 630 mm from forged billets, NLZ and ingot blanks ESR with a diameter of 600 mm by flashing them on the first cross-helical rolling mill into sleeves or blanks with rise in diameter from 6.0 to 10.0% and firmware-rolling them without heating in the second mill with a rise in diameter from 7 to 9.0%, depending on the diameter of the rolled pipes. When rolling pipes in small batches, this scheme makes it possible to carry out the process of flashing blanks and ingots-blanks of ESR of one diameter in one mill, and blanks and ingots-blanks of ESR of another diameter in the second mill and rolling pipes on pilgrim mills of different diameters with different wall thicknesses from different grades of steel and alloys. This technological scheme allows the process of compaction of NLZ and ingot-blanks of ESRs with a diameter of 600 mm in one mill into blanks, followed by their piercing into sleeves in the second mill and rolling them into pipes on pilgrim mills.

The objective of the proposed method is to develop a technological process for the production of pipes with a diameter of 273 to 630 mm on existing pipe rolling plants with pilgrim mills after their reconstruction, as well as on TPU with new generation pilgrim mills using forged billets, NLZ and ESR ingots-blanks with diameters from 440 to 600 mm, and commodity and conversion pipes with a diameter of 465 to 630 mm from hard-deformed steel grades and alloys from hollow ingot-blanks ESR with a diameter of 630-720 mm with optimal heating modes, firmware , Rolling, calibrating, processing, receipt and delivery pipes, with the highest performance and lowest coefficients of metal consumables.

, где ω_n=1,06-1,10 - значения коэффициента опережения металла в полирующем участке валка пилигримового стана, большее значение которого относится к трубам диаметром 273 мм; ρ_n - радиус валка на полирующем участке, мм; Θ_n - центральный угол полирующего участка валка, рад; µ - коэффициент вытяжки; m - величина подачи гильзы в очаг деформации пилигримового стана, мм; установившийся процесс прокатки на пилигримовом стане производят с фиксированными величинами подач m, вытяжек µ, при выполнении которых коэффициент полировки должен находиться в пределах 2,5≤K_n≤5,0. Для производства труб диаметром от 426 до 630 мм из углеродистых и низколегированных марок стали используют НЛЗ и сплошные слитки-заготовки ЭШП диаметром 600 мм, прокатку труб диаметром 530, 550, 610 и 630 мм производят по технологии: кованые заготовки, НЛЗ и слитки-заготовки ЭШП диаметром 600 мм прошивают в первом стане поперечно-винтовой прокатки в гильзы-заготовки с плавным кратным увеличением подъема по диаметру с 6,0 до 10%, от 1,0 до 1,5% под каждый размер труб; гильзы-заготовки без подогрева прошивают - раскатывают во втором стане поперечно-винтовой прокатки в гильзы с плавным кратным увеличением подъема по диаметру с 7,0 до 9,0%, от 0,5 до 1,0% под каждый размер труб, производство труб из труднодеформируемых марок стали и сплавов диаметром от 273 до 426 мм производят из слитков-заготовок ЭШП диаметром от 400 до 600 мм, а труб диаметром от 465 до 630 мм из полых слитков-заготовок ЭШП диаметром от 630 до 720 мм, прокатку товарных и передельных труб на пилигримовых станах производят одновременно одного или разных диаметров, а прокатку труб-плетей на пилигримовых станах производят с плавным подъемом верхнего валка за каждую подачу гильзы в очаг деформации, значение которого определяют из выражения

где D_г - диаметр дорна у дорновой головки, мм; D_з - диаметр дорна со стороны затравки, мм; m - величина подачи гильзы в очаг деформации; µ - коэффициент вытяжки; n - количество подач при прокатке труб-плетей данного размера, шт.The technical result is achieved by the fact that in the known method for the production of seamless pipes with a diameter of 273 to 630 mm in a pipe rolling installation with pilgrim mills, including heating continuously cast billets (NLZ), forged billets, solid or hollow ingots-blanks ESRs ranging in size from 400 to 650 mm to the temperature of ductility, flashing NLZ, forged blanks and ingots-blanks ESR in mills of cross-helical rolling on a short mandrel in sleeves or in sleeves-blanks on one mill, firmware-rolling of sleeves-blanks on a short contact in the second cross-helical rolling mill without heating or after reheating, blowing the sleeves, transporting the sleeves to the pilgrim mill, rolling the sleeves into tubes in rolls with a barrel diameter from 975 to 1250 mm with a 25-fold increase for each subsequent diameter pipe of dimensional series with calibres from 280 to 562 mm on mandrels with a taper from 1.0 to 6.0 mm depending on the linear expansion coefficient of steel, removal of technological trimmings - pilgrim heads and seed ends, pipe cutting to multiple lengths with hot cutting saws , heating in continuous sectional furnaces or furnaces with walking beams, pipe calibration, pipe transportation on sleeper with rotation, pipe straightening in six-roll machines and pipe acceptance, polishing coefficient is increased from 2.5 to 5.0 with increasing pipe diameters from 273 to 630 mm, the values of which are determined from the expression

where ω _n = 1,06-1,10 are the values of the advance coefficient of the metal in the polishing section of the roll of the pilgrim mill, the greater value of which relates to pipes with a diameter of 273 mm; ρ _n is the radius of the roll on the polishing section, mm; Θ _n is the central angle of the polishing portion of the roll, rad; µ is the drawing ratio; m is the feed rate of the liner into the deformation zone of the pilgrim mill, mm; the steady rolling process on the pilgrim mill is carried out with fixed feed rates m, hoods µ, during which the polishing coefficient must be within 2.5≤K _n ≤5.0. For the production of pipes with diameters from 426 to 630 mm from carbon and low alloy steel grades, NLZ and continuous ingot blanks ESR with a diameter of 600 mm are used, rolling pipes with a diameter of 530, 550, 610 and 630 mm are produced according to the technology: forged blanks, NLZ and ingot blanks ESRs with a diameter of 600 mm are flashed in the first cross-helical rolling mill into blanks with a gradual multiple increase in diameter rise from 6.0 to 10%, from 1.0 to 1.5% for each pipe size; the blanks without preheating are flashed - rolled in the second mill of cross-helical rolling into sleeves with a gradual multiple increase in diameter rise from 7.0 to 9.0%, from 0.5 to 1.0% for each pipe size, pipe production from hardly deformable grades of steel and alloys with a diameter of 273 to 426 mm, they are produced from ESR ingots-blanks with a diameter of 400 to 600 mm, and pipes with a diameter of 465 to 630 mm from hollow ESR ingots-blanks with a diameter of 630 to 720 mm, rolling commodity and conversion pipes on pilgrim mills produce at the same time one or different diameters ditch, and the rolling of the lash tubes on the pilgrim mills is carried out with a smooth rise of the upper roll for each feed of the sleeve into the deformation zone, the value of which is determined from the expression

where D _g is the diameter of the mandrel at the mandrel head, mm; D _s - the diameter of the mandrel on the side of the seed, mm; m is the feed rate of the sleeve into the deformation zone; µ is the drawing ratio; n is the number of feeds when rolling lashes of a given size, pcs.

, где ω_n=1,06-1,10 - значения коэффициента опережения металла в полирующем участке валка пилигримового стана, большее значение которого относятся к трубам диаметром 273 мм; ρ_n - радиус валка на полирующем участке, мм; Θ_n - центральный угол полирующего участка валка, рад; µ - коэффициент вытяжки; m - величина подачи гильзы в очаг деформации пилигримового стана, мм, установившийся процесс прокатки на пилигримовом стане производят с фиксированными величинами подач m, вытяжек µ, при выполнении которых коэффициент полировки должен находиться в пределах 2,5≤K_n≤5,0. Для производства труб диаметром от 426 до 630 мм из углеродистых и низколегированных марок стали используют НЛЗ и сплошные слитки-заготовки ЭШП диаметром 600 мм, прокатку труб диаметром 530, 550, 610 и 630 мм производят по технологии: кованые заготовки, НЛЗ и слитки-заготовки ЭШП диаметром 600 мм прошивают в первом стане поперечно-винтовой прокатки в гильзы-заготовки с плавным кратным увеличением подъема по диаметру с 6,0 до 10%, от 1,0 до 1,5% под каждый размер труб; гильзы-заготовки без подогрева прошивают-раскатывают во втором стане поперечно-винтовой прокатки в гильзы с плавным кратным увеличением подъема по диаметру с 7,0 до 9,0%, от 0,5 до 1,0% под каждый размер труб, производство труб из труднодеформируемых марок стали и сплавов диаметром от 273 до 426 мм производят из слитков-заготовок ЭШП диаметром от 400 до 600 мм, а труб диаметром от 465 до 630 мм из полых слитков-заготовок ЭШП диаметром от 630 до 720 мм, прокатку товарных и передельных труб на пилигримовых станах производят одновременно одного или разных диаметров, а прокатку труб-плетей на пилигримовых станах производят с плавным подъемом верхнего валка за каждую подачу гильзы в очаг деформации, значение которого определяют из выражения

где D_г - диаметр дорна у дорновой головки, мм; D_з - диаметр дорна со стороны затравки, мм; m - величина подачи гильзы в очаг деформации; µ - коэффициент вытяжки; n - количество подач при прокатке труб-плетей данного размера, шт. Таким образом, эти отличия позволяют сделать вывод о соответствии критерию «изобретательский уровень».A comparative analysis of the proposed solution with the closest analogue shows that the inventive method for the production of pipes with a special diameter of 273 to 630 mm on a pipe-rolling installation with pilgrim mills differs from the known one in that they heat continuously cast billets (NLZ), forged billets, solid or hollow ingots - ESR blanks from 400 to 650 mm in size to ductility temperature, flashing NLZ, forged blanks and ingot blanks ESR in cross-helical rolling mills on a short mandrel in sleeves or in sleeves forging on one mill, firmware - rolling out the blanks on a short mandrel on the second cross-helical rolling mill without heating or after reheating, blowing the sleeves, transporting the sleeves to a pilgrim mill, rolling the sleeves into tubes in rolls with a barrel diameter from 975 to 1250 mm with a multiple of 25 mm increase for each subsequent diameter of a pipe of a size range with calibres from 280 to 562 mm on mandrels with a taper from 1.0 to 6.0 mm depending on the coefficient of linear expansion of steel, removal of technological trim - pilgrim holo ok and seed ends, cutting pipes to multiple lengths using hot cutting saws, heating in continuous sectional furnaces or furnaces with walking beams, calibrating pipes, transporting pipes on sleeper with rotation, straightening pipes in six-roll machines and accepting pipes, increase the polishing coefficient from 2, 5 to 5.0 with an increase in pipe diameters from 273 to 630 mm, the values of which are determined from the expression

where ω _n = 1,06-1,10 are the values of the advance coefficient of the metal in the polishing section of the roll of the pilgrim mill, the greater value of which relates to pipes with a diameter of 273 mm; ρ _n is the radius of the roll on the polishing section, mm; Θ _n is the central angle of the polishing portion of the roll, rad; µ is the drawing ratio; m is the feed rate of the sleeve into the deformation center of the pilgrim mill, mm, the steady rolling process on the pilgrim mill is carried out with fixed feeds m, hoods µ, during which the polishing coefficient should be in the range 2.5≤K _n ≤5.0. For the production of pipes with diameters from 426 to 630 mm from carbon and low alloy steel grades, NLZ and continuous ingot blanks ESR with a diameter of 600 mm are used, rolling pipes with a diameter of 530, 550, 610 and 630 mm are produced according to the technology: forged blanks, NLZ and ingot blanks ESRs with a diameter of 600 mm are flashed in the first cross-helical rolling mill into blanks with a gradual multiple increase in diameter rise from 6.0 to 10%, from 1.0 to 1.5% for each pipe size; sleeves blanks without heating are stitched-rolled in the second mill of cross-helical rolling into sleeves with a gradual multiple increase in diameter rise from 7.0 to 9.0%, from 0.5 to 1.0% for each pipe size, pipe production from hardly deformable grades of steel and alloys with a diameter of 273 to 426 mm, they are produced from ESR ingots-blanks with a diameter of 400 to 600 mm, and pipes with a diameter of 465 to 630 mm from hollow ESR ingots-blanks with a diameter of 630 to 720 mm, rolling commodity and conversion pipes on pilgrim mills produce at the same time one or different diameter s, and rolling the lash tubes on the pilgrim mills is carried out with a smooth rise of the upper roll for each feed of the sleeve into the deformation zone, the value of which is determined from the expression

where D _g is the diameter of the mandrel at the mandrel head, mm; _Of D - diameter of the mandrel from the seed mm; m is the feed rate of the sleeve into the deformation zone; µ is the drawing ratio; n is the number of feeds when rolling lashes of a given size, pcs. Thus, these differences allow us to conclude that the criterion of "inventive step" is met.

Comparison of the proposed method not only with the prototype, but also with other technical solutions in the art did not allow them to identify signs that differ the claimed solution from the prototype, which corresponds to the patentability of "inventive step".

Since there is no similar method and equipment in world practice, it is not possible to give an example of a concrete implementation in a given period of time. Instead of an example of a specific implementation, the technological sequence of operations for the production of commodity and conversion pipes with a size of 273-630 mm is given. In accordance with paragraphs. 1 and 4 of the claims, the rolling of pipes with a diameter of 273 to 630 mm from carbon and alloy steel grades is carried out from forged, NLZ and ingot blanks ESR with a diameter of 400 to 600 mm, pipes from hard-deformed grades of steel and alloys with a diameter of 273 to 426 mm from ESR ingots-blanks with a diameter of 400 to 600 mm, and tubes with a diameter of 465 to 630 mm from hollow ESR ingots-blanks with a diameter of 630 to 720 mm in rolls with a barrel diameter of 975 to 1250 mm with a polishing coefficient of 2.5≤K _n ≤5.0. In accordance with paragraph 2 of the claims, the polishing coefficient is increased from 2.5 to 5.0 with an increase in pipe diameters from 273 to 630 mm. The steady rolling process on the pilgrim mill is carried out with fixed feed rates m, hoods µ, during which the polishing coefficient should be within 2.5≤K _n ≤5.0. In accordance with paragraphs. 5, 6 and 7 of the claims, the rolling of pipes with a diameter of 530, 550, 610 and 630 mm is carried out according to the technology: forged billets, steel billets and ingots-blanks of ESRs with a diameter of 600 mm are stitched in the first mill of cross-helical rolling into blanks with a gradual multiple increase diameter rise from 6.0 to 10%, from 1.0 to 1.5% for each pipe size; the blanks without preheating are flashed - rolled in the second cross-helical rolling mill into sleeves with a gradual multiple increase in diameter rise from 7.0 to 9.0%, from 0.5 to 1.0% for each pipe size. The production of pipes from hardly deformable grades of steel and alloys with a diameter of 273 to 426 mm is made from ingot blanks of ESR with a diameter of 400 to 600 mm, and pipes with a diameter of 465 to 630 mm from hollow ingot blanks of ESR with a diameter of 630 to 720 mm. Commodity and conversion pipes are rolled on pilgrim mills at the same time in one or different diameters. In accordance with paragraph 8 of the claims, rolling of the lash tubes on the pilgrim mills is carried out with a smooth rise of the upper roll for each feed of the sleeve into the deformation zone.

Thus, the use of this method and composition of equipment will allow for the first time in world practice to produce smooth, threaded, boiler, thick-walled and special-purpose pipes with a diameter of 273 to 630 mm with wall thicknesses of 6.0 to 90 mm in a pipe rolling plant with pilgrim mills from forged billets, NLZ, ingot billets of ESR with a diameter of 400 to 600 mm with maximum productivity, and pipes from hard to deform steel grades and alloys with a diameter of 465 to 630 mm from hollow ingots-blanks of ESR with a diameter of 630 up to 720 mm with increased geometric parameters, to ensure the country's need for pipes of this assortment, to produce competitive products and export it to other countries of the world.

Claims (8)

1. Method for the production of seamless pipes with a diameter of 273 to 630 mm in a tube mill with pilgrim mills, including heating continuously cast billets (NLZ), forged billets, solid or hollow ingots-blanks ESRs in sizes from 400 to 650 mm to ductility temperature, firmware NLZ, forged blanks and ESR ingots-blanks in mills of cross-helical rolling on a short mandrel in sleeves or in sleeves-blanks on one mill, firmware - rolling of sleeves-blanks on a short mandrel on the second mill of cross-helical rolling without reheating or after reheating, purging the sleeves, transporting the sleeves to the pilgrim mill, rolling the sleeves into tubes in rolls with a barrel diameter of 975 to 1250 mm with a multiple of 25 mm increase for each subsequent pipe diameter size range with calibres from 280 to 562 mm per mandrels with a taper from 1.0 to 6.0 mm depending on the linear expansion coefficient of steel, removal of technological trimmings in the form of pilgrim heads and seed ends, pipe cutting to multiple lengths with hot cutting saws, heating in continuous sectional furnaces or furnaces with walking beams, pipe calibration, pipe transportation on sleeper with rotation, pipe straightening in six-roll machines and pipe receiving. 2. The method according to p. 1, characterized in that the polishing coefficient is increased from 2.5 to 5.0 with an increase in pipe diameters from 273 to 630 mm, the values of which are determined from the expression

where ω _n = 1,06-1,10 - the values of the advance coefficient of the metal in the polishing section of the roll of the pilgrim mill, a larger value of which relates to pipes with a diameter of 273 mm;
ρ _n is the radius of the roll on the polishing section, mm;
Θ _n is the central angle of the polishing portion of the roll, rad;
µ is the drawing ratio;
m is the feed rate of the sleeve into the deformation zone of the pilgrim mill, mm. 3. The method according to p. 1, characterized in that the steady-state rolling process on the pilgrim mill is carried out with fixed feeds m, hoods µ, during which the polishing coefficient must be within 2.5≤K _n ≤5.0. 4. The method according to p. 1, characterized in that for the production of pipes with a diameter of 426 to 630 mm from carbon and low alloy steel grades, NLZ and continuous ingot blanks ESR with a diameter of 600 mm are used. 5. The method according to p. 1, characterized in that the rolling of pipes with a diameter of 530, 550, 610 and 630 mm is carried out according to the technology in which forged billets, billets and ingots-blanks ESR with a diameter of 600 mm are stitched in the first cross-helical mill blanks with a gradual multiple increase in diameter rise from 6.0 to 10%, from 1.0 to 1.5% for each pipe size, and blanks without stitching are stitched - rolled into sleeves in a second cross-helical mill with a smooth multiple increase in diameter rise from 7.0 to 9.0% from 0.5 to 1.0% for each pipe size . 6. The method according to p. 1, characterized in that the production of pipes from hardly deformable grades of steel and alloys with a diameter of 273 to 426 mm is made from ingot blanks ESR with a diameter of 400 to 600 mm, and pipes with a diameter of 465 to 630 mm from hollow ingots - ESH blanks with a diameter of 630 to 720 mm. 7. The method according to p. 1, characterized in that they produce rolling commodity and conversion pipes on pilgrim mills at the same time of one or different diameters. 8. The method according to p. 1, characterized in that the rolling tubes-lashes on the pilgrim mills are produced with a smooth rise of the upper roll for each feed sleeve into the deformation zone, the value of which is determined from the expression

where D _g is the diameter of the mandrel at the mandrel head, mm;
D _s - the diameter of the mandrel on the side of the seed, mm;
m is the feed rate of the sleeve into the deformation zone;
µ is the drawing ratio;
n is the number of feeds when rolling lashes of a given size, pcs.