RU2516161C1 - Method to produce seamless pipes with size of 377h14-60 mm for steam boilers, steam lines and headers of plants with high and supercritical parameters of steam from steel of grade 10h9mfb-sh - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: method includes melting of bars by electroslag melting, boring and turning of bars into bars-stocks with size 600×vn.240×2100±50 mm, heating of bars-stocks to temperature of plasticity, their punching-rolling in a cross-rolling mill into cartridges-stocks. After cooling the cartridges-stocks are repeatedly heated to plasticity temperature, punched and rolled in the cross-rolling mill into cartridges with size 620×vn.415×2860-3000 mm and rolled into tube stocks with size of 426×21×15300-16200 and 426×23×13800-14700 mm with drawings µ=6.24 and µ=5.72, pressing along the diameter 30.6% and with feed of cartridges to a deformation focus m=16-19 mm. Tube stocks are cut into two pipes-arms, and pipes-arms are rolled into commercial pipes with size of 377×14-19 mm.

EFFECT: invention provides for production of pipes with geometric dimensions, mechanical properties and quality of surface exceeding requirements of existing technical conditions.

5 cl, 1 tbl

Description

The invention relates to pipe rolling production, and in particular, to a method for the production of seamless pipes with a size of 377 × 14-19 mm for steam boilers, steam pipelines and manifolds of plants with high and supercritical parameters of steam from hollow ingots-blanks of electroslag remelting steel grade 10X9MFB-Sh and can be used on an 8-16 ″ pipe-rolling installation with pilgrim mills in the manufacture of redistributed pipes of 426 × 21 and 426 × 23 mm in size for their subsequent rolling on the KhPT450 mill into commodity pipes of 377 × 14-19 mm in size with increased requirements geometrical dimensions, mechanical properties and surface quality.

In the practice of pipe production, there is a method of manufacturing boiler pipes of large and medium diameters from forged billets of steels of grades 20, 15GS, 15XM, 12X1MF, 15X1M1F, 12X2MFSR, 10X9MFB, 12X11V2MF, 08X16H9M2, 12X18N12T, 10Kh13G12B2K2 with mechanical properties that include forging them into forgings (compaction of the structure) with a yoke of ≥2.5, machining the forgings into billets (turning with metal removal of 10-15 mm per side), drilling in the blanks of a central hole with a diameter of 100 ± 5 mm to remove the central quatational porosity and nonmetallic inclusions, heating the workpieces to the ductility temperature, piercing the workpieces in a cross-helical rolling mill into sleeves, rolling the sleeves into tubes with a diameter of 245-550 mm on a pilgrim installation 8-16 '' with a diameter tolerance of + 1.25 / - 1,0 and wall thickness + 25 / -5% (TU 14-1-2560-78 "Forged pipe billets for boiler pipes", TU 14-3-460-2003 and TU 14-3R-55-2001 "Steel pipes seamless for steam boilers and pipelines ”and TU 14-3-420-75“ Pipes for steam boilers and pipelines made of steel 15GS and 15Kh1M1F ”).

The disadvantage of this method is the high energy intensity of the process associated with heating and deformation (forging) of the ingots into forgings, followed by turning and drilling of the central hole, heating the workpieces to a plasticity temperature, piercing and rolling them into pipes on pilgrim mills with a wall tolerance of + 20 / - 5%, increased consumption coefficient of the metal during the redistribution of the ingot - forging - billet - pipe and, as a result, the high cost of pipes, as well as the fact that this steel grade, although included in TU 14-3R-55-2001, but the pipes are made of her to nast yaschego has not been made.

In pipe production, there is a known method for manufacturing large diameter gas lift pipes from 09G2S steel ingots for the production of ESR and VDP (Patent RU No. 2119395, Cl. B21B 19/04), where the ingots are deformed in the piercing mill along the crystals, setting the ingots in the mill with the head part, and stitched with a posad in diameter by the amount

D = 2S _G (1-sinα) / S _C ,

where S _G - wall thickness of the sleeve, mm;

S _C - wall thickness of the drilled ingot ESR, mm;

α is the angle of inclination of the crystallization front to the axis of the ingot, deg.

The disadvantage of this method of manufacturing large diameter pipes from ingots of ESR and VDP steel grade 09G2S is the need to manufacture macro templates to determine the angle of inclination of the crystallization front to the axis of the ingot, and the piercing of the ingots with shrink (head) part forward leads to the formation of defects in the form of internal captures at the front ends of the sleeves .

In pipe production, there is also a known method for the production of large diameter boiler pipes from ESR ingots (patent RU No. 2180874, Cl. B21B 19/04), which reduces energy costs, reduces metal consumption and, as a result, reduces the cost of boiler pipes through the use of large diameter ingots and conducting the firmware process with a posad in diameter equal to 8-16%.

The disadvantages of this method are the fact that due to the low power of the drive of the piercing mill of ChTPZ OJSC, it is not possible to flash ESR steel of the 10Kh9MFB-Sh grade with a pitch of 8-16% in diameter.

There is also known a method for the production of seamless hot-deformed pipes of large and medium diameters in tube rolling plants with pilgrim mills for steam boilers, steam pipelines and manifolds of plants with high and supercritical parameters of steam from electroslag remelting ingots and continuously cast billets (patent RU No. 232322314, Cl. B21B 19 / 04), which provides for the piercing of ESHP and NLZ ingots in cross-helical rolling mills with a diameter fit depending on the grade of steel and the total hood during redistribution of the electric wire ingot What are the melting-pipe or continuously cast billet, tube, wherein the values posad diameter ingots electroslag remelting in piercing mills into helical rolling determined from the expression

Δ _i′ashp = k _i′eshp µ _i Σ,

where Δ _i′eshp are the values of the sizes according to diameter when piercing in the helical rolling mills of ESR ingots of i-steel grade,%;

µ _i Σ = µ _ave. µ _p - the total drawing coefficient when rolling pipes of the i-th size;

k _i'eshp - coefficient taking into account the size of the gang in diameter when flashing sleeves from ESR ingots of i-steel grade,%;

µ _pr. - the coefficient of drawing when flashing sleeves for rolling pipes of the i-th size;

µ _p. is the drawing coefficient when rolling j-size pipes on a pilgrim mill, while the coefficients k _i′eshp for different steel grades vary from 24 to 40.

The disadvantage of this method is that it is very difficult to manufacture, because each pipe size requires its own ESR ingots, this method extends to the production of seamless hot-deformed pipes of large and medium diameters in tube rolling plants with pilgrim mills made of carbon steel grades and does not provide production of boiler tubes from EShP ingots of steel grade 10X9MFB-Sh.

In pipe production, there is also known a method for the production of hot-rolled conversion and commodity pipes of large and medium diameters from hard-to-deform grades of steel and alloys in tube-rolling plants with pilgrim mills (Patent RU No. 2278750, Cl. B21B 21/00), including turning of ESR ingots and forged billets, drilling a central hole with a diameter of 100 ± 5 mm, heating them to a plasticity temperature, piercing them with subsequent rolling in a cross-helical mill into shells and rolling the shells in a pilgrim mill into hot-rolled processing pipes or pipes with a relatively thick wall, with the first piercing of ESR ingots and forged billets in a cross-helical rolling mill with the bottom end forward, and the second piercing-rolling with the shrink end forward, the pipes are rolled on a pilgrim mill with diameter to the wall thickness D / S = 6.5-8.0 with a hood µ≤4.5.

The disadvantage of this method is that it includes heating the ESR ingots and billets to a temperature of ductility, flashing them in a cross-helical rolling mill into billet sleeves, reheating the billet blanks from a cold or hot embankment to a ductility temperature, flashing-rolling in the mill cross-helical rolling into sleeves with their subsequent rolling in a pilgrim mill to commodity or conversion pipes. Double heating leads to double burning of the metal, and the flashing of ESR ingots and billets into blanks, followed by rolling them into sleeves leads to a 2-fold loss in the performance of the pilgrim installation, and, consequently, to an increase in the cost of commodity and conversion pipes. This method extends to the production of seamless hot-deformed conversion and commodity pipes of large and medium diameters in tube-rolling plants with pilgrim mills from hard-to-deform grades of steel and alloys and does not provide for the production of boiler tubes from solid and hollow ingots of 10-H9MFB-Sh steel ESH.

The closest technical solution is a method for preparing billets for rolling commodity and conversion pipes of large and medium diameters from hard-to-deform grades of steel and alloys in pipe rolling plants with pilgrim mills (Patent RU No. 2340417, Cl. B21B 21/00), including casting hollow ingots-sleeves electroslag remelting, turning and boring them into hollow billets with metal removal, the value of which is determined from the expressions

Δ = K * D / S,

Δ ₁ = K ₁ * D / S,

where Δ is the value of the removed metal layer when turning hollow ingots-shells ESR, mm; Δ ₁ - the value of the removed metal layer when boring hollow ingots-shells ESR, mm; D is the outer diameter of the hollow ingots, sleeves, mm; S is the wall thickness of the hollow ingots, sleeves, mm; K = 0.3-0.4 is a coefficient for determining the magnitude of the metal layer to be removed when turning ingot shells, large values of which relate to steels with a high content of alloying elements; K ₁ = 0.4-0.5 is the coefficient for determining the size of the metal layer to be removed when bore ingots-shells, large values of which relate to steels with a high content of alloying elements, and the bottom of the hollow ingots-shells of ESR is removed by anode-mechanical cutting the value of which is determined from the expression

L = K ₂ * D / S,

where K ₂ = 15-20 is the coefficient for determining the magnitude of the removed bottom of the ingot shells, large values of which relate to steels with a high content of alloying elements.

The disadvantage of this method is that it is directed to the technology of converting hollow ESR ingots into hollow ingots-blanks for the production of pipes from hard-to-form steel grades and alloys and does not solve the technological issues of the production of seamless pipes for steam boilers, steam pipelines and collectors of installations with high and supercritical parameters a pair of steel grade 10X9MFB-Sh with a diameter of 377 mm with wall thicknesses from 14 to 19 mm.

In Russia, boiler pipes with a diameter of 377 mm with different wall thicknesses can only be produced at TPU 8-16 ″ with pilgrim mills and at the KhPT450 mill.

Rolling pipes of 377 × 14-19 mm in size on TPU 8-16 ″ with pilgrim mills made of 10Kh9MFB-Sh steel is problematic due to the low temperature under deformation of 1180-1200 ° C. For rolling pipes with a size of 377 × 14-19 mm, ESR ingots-blanks with a size of 540 × 100 × 1750 ± 50 mm are required, of which on a cross-helical rolling mill for piercing and rolling we get sleeves with a size of 560 × ext. 390 × 3250-3440 and 560 × in. 375 × 2850-3000 mm or hollow billet blanks with a size of 600 × in. 400 × 3200 ± 50 mm. The rolling time of a pipe measuring 377 × 14 mm from a sleeve with a length of 2850 mm and a wall thickness of 72.5 mm on a pilgrim mill is more than 4.5 minutes. During this period of time, the sleeve tube cools below 800 ° C (at a recommended minimum of 850 ° C at the end of rolling). Rolling pipes 377 × 14-19 mm in size and rolling pilgrim heads made of 10Kh9MFB-Sh steel at temperatures below 850 ° C leads to increased loads on the pilgrim mill drive and tightening mandrels, which in turn leads to breakage of the safety bolts and spindles of the pilgrim mill , reduced productivity due to the removal of mandrels due to puffs, replacement of safety bolts and spindles. To avoid tightening the mandrels, it is necessary to roll pipes on mandrels with a taper of 5-6 mm instead of the existing taper of 1.0 mm, and this will lead to a longitudinal difference, i.e. to increased rejection of pipes by wall thickness. Rolling pipes from steel grade 10X9MFB-Sh with a D / S ratio> 20 leads to increased loads on the drive of the pilgrim mill and the formation of bumps on the outer surface of the pipes, i.e. to increased rejection by the outer diameter and wall thickness.

The objective of the proposed method (invention) is the development of the production of seamless pipes with a size of 377 × 14-19 mm for steam boilers, steam pipelines and manifolds of plants with high and supercritical steam parameters with increased requirements for geometric dimensions, mechanical properties and surface quality from hot rolled pipe sizes 426 × 21 and 426 × 23 mm.

до $${\mu }_{\Sigma }^1=\text{10}\text{,89}$$

, меньшие значения которых относятся к трубам с меньшими отношениями D/S, и определяются из выражений µ_Σ=µ_пр.µ_п, $${\mu }_{\Sigma }^1={\mu }_{\Sigma }{\mu }_x$$

, где µ_пр. - вытяжка при прошивке-раскатке полых слитков-заготовок в гильзы в стане поперечно-винтовой прокатки; µ_п - вытяжка при прокатке передельных труб на пилигримовом стане; µ_х - вытяжка при перекатке передельных труб в товарные на стане ХПТ450, полые слитки электрошлакового переплава для прокатки передельных труб отливают с отношением диаметра к толщине стенки D/S=5,2-5,3, которые обтачивают и растачивают в полые слитки-заготовки с отношением диаметра к толщине стенки D/S=5,9-6,0, большие значения которых относятся к полым слиткам и слиткам-заготовкам для прокатки передельных горячекатаных труб с меньшими толщинами стенок, полые слитки-заготовки нагревают в методической печи по технологии: посад слитков-заготовок производят на колосники печи партиями по 8-10 штук в один ряд с интервалом через 1,25-1,5 часа при температуре в третьей зоне печи 1000-1050°C; выдержка слитков-заготовок на колосниках без кантовки в течении 1,0-1,25 часа; нагрев слитков-заготовок диаметром 600 мм с отношением D/S=5,9-6,0 со скоростью 2,5-2,9°C в минуту в течение 4,5-5,0 часа до температуры 1180-1200°C с равномерной кантовкой слитков-заготовок по подине печи с 22-го по 6-е окно через 18-20 минуту на угол 220-230°; кантовка с 4-го окна на яму печи и выдача заготовок из печи с температурой центра слитков-заготовок 1180-1200°C, большие значения которой относятся к передельным трубам с меньшей толщиной стенки.The technical result is achieved by the fact that in the known method for the production of seamless pipes with a size of 377 × 14-19 mm for steam boilers, steam pipelines and manifolds of plants with high and supercritical steam parameters from 10Kh9MFB-Sh steel, including ingots melting by electroslag remelting, machining-turning ingots into ingot billets, drilling in ingot billets of a central hole with a diameter of 100 ± 5 mm, heating the ingot billets to a plasticity temperature, piercing them in a cross-helical rolling mill into sleeves preparations, cooling of shell blanks, repair of shell blanks, if necessary, reheating of shell blanks from a cold embankment to a ductile temperature, flashing-rolling of shell blanks in a cross-helical rolling mill into shells, rolling of shell sleeves in pilgrim mills into commodity pipes size 377 × 20-60 mm, heat treatment, etching, dressing, ultrasonic inspection and acceptance of pipes with a tolerance of + 1.25 / -1.0% in diameter and + 20 / -5.0% wall thickness, 377 × pipes 14-19 mm are produced by the cold rolling method at the KhPT450 mill from hot-rolled pipes of 426 × 21 and 426 × 23 mm in size, hot-rolled tubes of 426 × 21 and 426 × 23 mm in size are produced from hollow ingots of electroslag remelting, which are turned and bored into hollow ingots of 600 × vn. 240 × 2100 ± 50 mm, hollow ingots-billets are heated to a temperature of 1180-1200 ° C, stitched-rolled in a cross-helical mill on a mandrel with a diameter of 400 mm in sleeves measuring 620 × in. 415 × 2860-3000 mm with a hood µ = 1.4, with a diameter increase of δ = 3.3% and rolled on TPU 8-16 ″ with pilgrim mills into pipes of 426 × 21 × 15300-16200 and 426 × 23 × 138 in size 00-14700 mm with hoods, respectively, µ = 6.24 and µ = 5.72, compression in diameter Δ = 30.6% and with feeds of sleeves into the deformation zone m = 16-19 mm, a piece of process waste - seed ends and pilgrim heads with a hot cutting saw, straightening on a six-roll straightening machine, heat treatment, repair, if necessary, cut into two pipes of equal length and taken with a tolerance of + 1.25 / -1.0 in diameter and ± 12 wall thickness, 5%, conversion pipes 426 × 21 × 7650-8100 mm in size are rolled on the KhPT450 mill into commodity cold-rolled pipes of 377 × 14 × 12550-13 100, 377 × 15 × 11600-12300 and 377 × 16 × 10800-11500 mm with hoods, respectively, µ = 1.67, µ = 1.57 and µ = 1.47, and the conversion pipes are 426 × 23 × 6900 -7350 mm are rolled on the KhPT450 mill into commodity pipes of 377 × 17 × 10100-10750, 377 × 18 × 9500-10100 and 377 × 19 × 9000-9600 mm sizes with hoods, respectively μ = 1.52, μ = 1.43 and µ = 1.36, perform heat treatment, straightening, ultrasonic testing and acceptance of pipes with tolerances of ± 1.0% in diameter and wall thickness + 15 / -5%, hot-rolled pipe converted to a pilgrim mill with total hoods from µ _Σ = 8.73 to µ _Σ = 8.01, and commodity cold-rolled pipes 377 × 14-19 mm in size produce with total hoods $${\mu }_{\Sigma }^{\mathrm{one}}=\text{fourteen}\text{, 58}$$

before $${\mu }_{\Sigma }^{\mathrm{one}}=\text{10}\text{, 89}$$

, the smaller values of which relate to pipes with lower D / S ratios, and are determined from the expressions μ _Σ = μ _ave μ _p , $${\mu }_{\Sigma }^{\mathrm{one}}={\mu }_{\Sigma }{\mu }_x$$

, where µ _ave. - hood for flashing-rolling hollow ingots-blanks into sleeves in a cross-helical rolling mill; µ _p - hood when rolling pigs on a pilgrim mill; µ _x - hood when rolling the conversion pipes into commodity ones at the KhPT450 mill, hollow ingots of electroslag remelting for rolling conversion pipes are cast with a ratio of diameter to wall thickness D / S = 5.2-5.3, which are turned and bored into hollow ingots with a ratio of diameter to wall thickness D / S = 5.9-6.0, large values of which relate to hollow ingots and ingot blanks for rolling hot rolled pipe with smaller wall thicknesses, hollow ingot blanks are heated in a methodical furnace using the technology: planting ingots produce on the furnace grates in batches of 8-10 pieces in a row with an interval after 1.25-1.5 hours at a temperature in the third zone of the furnace 1000-1050 ° C; aging ingots-blanks on grates without tilting for 1.0-1.25 hours; heating of ingot blanks with a diameter of 600 mm with a ratio D / S = 5.9-6.0 at a speed of 2.5-2.9 ° C per minute for 4.5-5.0 hours to a temperature of 1180-1200 ° C with uniform pitching of ingot blanks along the bottom of the furnace from the 22nd to the 6th window in 18-20 minutes at an angle of 220-230 °; tilting from the 4th window to the furnace pit and delivery of billets from the furnace with the temperature of the center of the ingot-billets 1180-1200 ° C, large values of which relate to redistribution pipes with a smaller wall thickness.

до $${\mu }_{\Sigma }^1=\text{10}\text{,89}$$

, меньшие значения которых относятся к трубам с меньшими отношениями D/S, и определяются из выражений µ_Σ=µ_пр.µ_п, $${\mu }_{\Sigma }^1={\mu }_{\Sigma }{\mu }_x$$

, где µ_пр. - вытяжка при прошивке-раскатке полых слитков-заготовок в гильзы в стане поперечно-винтовой прокатки; µ_п - вытяжка при прокатке передельных труб на пилигримовом стане; µ_х - вытяжка при перекатке передельных труб в товарные на стане ХПТ450, полые слитки электрошлакового переплава для прокатки передельных труб отливают с отношением диаметра к толщине стенки D/S=5,2-5,3, которые обтачивают и растачивают в полые слитки-заготовки с отношением диаметра к толщине стенки D/S=5,9-6,0, большие значения которых относятся к полым слиткам и слиткам-заготовкам для прокатки передельных горячекатаных труб с меньшими толщинами стенок, полые слитки-заготовки нагревают в методической печи по технологии: посад слитков-заготовок производят на колосники печи партиями по 8-10 штук в один ряд с интервалом через 1,25-1,5 часа при температуре в третьей зоне печи 1000-1050°C; выдержка слитков-заготовок на колосниках без кантовки в течении 1,0-1,25 часа; нагрев слитков-заготовок диаметром 600 мм с отношением D/S=5,9-6,0 со скоростью 2,5-2,9°C в минуту в течение 4,5-5,0 часа до температуры 1180-1200°C с равномерной кантовкой слитков-заготовок по подине печи с 22-го по 6-е окно через 18-20 минуту на угол 220-230°; кантовка с 4-го окна на яму печи и выдача заготовок из печи с температурой центра слитков-заготовок 1180-1200°C, большие значения которой относятся к передельным трубам с меньшей толщиной стенки. Таким образом, эти отличия позволяют сделать вывод о соответствии критерию «изобретательский уровень».Comparative analysis with the prototype shows that the inventive method for the production of seamless pipes with a size of 377 × 14-19 mm for steam boilers, steam pipelines and manifolds of installations with high and supercritical parameters of steam from steel grade 10X9MFB-Sh, differs in that pipes with a size of 377 × 14- 19 mm is produced by the cold rolling method at the KhPT450 mill from hot-rolled steel tubes of 426 × 21 and 426 × 23 mm in size, hot-rolled steel tubes of 426 × 21 and 426 × 23 mm in size are made from hollow electroslag ingots that are grinded and bored they are poured into hollow ingots-blanks with a size of 600 × ext. 240 × 2100 ± 50 mm, hollow ingots-blanks are heated to a temperature of 1180-1200 ° C, stitched-rolled in a cross-helical mill on a mandrel with a diameter of 400 mm in sleeves of 620 × ext. 415 × 2860-3000 mm with a hood µ = 1.4, diameter rise δ = 3.3% and rolled on TPU 8-16 ″ with pilgrim mills into pipes of sizes 426 × 21 × 15300-16200 and 426 × 23 × 13800-14700 mm with hoods, respectively, µ = 6.24 and µ = 5.72, compression in diameter Δ = 30.6% and with feeds of sleeves into the deformation zone m = 16-19 mm, a piece of technological waste is produced - seed ends and pilgrim heads with a hot cutting saw, dressing on a six-roll straightening machine, heat treatment, repair, if necessary, cut into two pipes of equal length and accept with a tolerance of + 1.25 / -1.0 in diameter and ± 12.5 in wall thickness %, conversion pipes of 426 × 21 × 7650-8100 mm in size are rolled on the KhPT450 mill into commodity cold-rolled pipes of 377 × 14 × 12550-13100, 377 × 15 × 11600-12300 and 377 × 16 × 10800-11500 mm sizes with hoods, respectively , µ = 1.67, µ = 1.57 and µ = 1.47, and the conversion pipes of 426 × 23 × 6900-7350 mm in size are rolled on the KhPT450 mill into commodity pipes of 377 × 17 × 10100-10750, 377 × 18 × 9500-10100 and 377 × 19 × 9000-9600 mm with hoods, respectively µ = 1.52, µ = 1.43 and µ = 1.36, heat treatment, dressing, ultrasonic inspection and pipe acceptance with tolerances in diameter of ± 1.0% and wall thickness + 15 / -5%, hot-rolled steel tubes on a pilgrim mill are produced with total hoods from µ _Σ = 8.73 to µ _Σ = 8.01, and commodity cold-rolled tubes 377 × 14-19 mm produced with total hoods $${\mu }_{\Sigma }^{\mathrm{one}}=\text{fourteen}\text{, 58}$$

before $${\mu }_{\Sigma }^{\mathrm{one}}=\text{10}\text{, 89}$$

, the lower values of which relate to pipes with lower D / S ratios, and are determined from the expressions μ _Σ = μ _ave μ _p , $${\mu }_{\Sigma }^{\mathrm{one}}={\mu }_{\Sigma }{\mu }_x$$

, where µ _ave. - hood for flashing-rolling hollow ingots-blanks into sleeves in a cross-helical rolling mill; µ _p - hood when rolling pigs on a pilgrim mill; µ _x - hood when rolling the conversion pipes into commodity ones at the KhPT450 mill, hollow ingots of electroslag remelting for rolling conversion pipes are cast with a ratio of diameter to wall thickness D / S = 5.2-5.3, which are turned and bored into hollow ingots with a ratio of diameter to wall thickness D / S = 5.9-6.0, large values of which relate to hollow ingots and ingot blanks for rolling hot rolled pipe with smaller wall thicknesses, hollow ingot blanks are heated in a methodical furnace using the technology: planting ingots produce on the furnace grates in batches of 8-10 pieces in a row with an interval after 1.25-1.5 hours at a temperature in the third zone of the furnace 1000-1050 ° C; aging ingots-blanks on grates without tilting for 1.0-1.25 hours; heating of ingot blanks with a diameter of 600 mm with a ratio D / S = 5.9-6.0 at a speed of 2.5-2.9 ° C per minute for 4.5-5.0 hours to a temperature of 1180-1200 ° C with uniform pitching of ingot blanks along the bottom of the furnace from the 22nd to the 6th window in 18-20 minutes at an angle of 220-230 °; tilting from the 4th window to the furnace pit and delivery of billets from the furnace with the temperature of the center of the ingot-billets 1180-1200 ° C, large values of which relate to redistribution pipes with a smaller wall thickness. 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 distinguish the claimed method from the prototype, which corresponds to patentability "inventive step".

Rolling mill with a size of 426 × 23 mm from 10Kh9MFB-Sh steel was produced at TPU 8-16 ″ with pilgrim mills from hollow ingots-blanks EShB measuring 600 × in. 240 × 2100 ± 50 mm. For comparison, these pipe sizes were rolled according to the classical scheme, i.e. from ingot blanks measuring 565 × 100 × 1750 ± 50 mm. Conveyor pipes measuring 426 × 23 mm were rolled at the KhPT450 mill into commodity pipes with a size of 377 × 18 mm. The data on the rolling of conversion pipes 426 × 23 mm in size from 10Kh9MFB-Sh steel to TPU 8-16 ″ with pilgrim mills and their rolling on the KhPT450 mill into commodity pipes 377 × 18 mm in size and the delivery results are shown in Table 1. For comparison table 1 shows the data on rolling of conversion tubes of size 426 × 23 mm from ingots-blanks ESR. From table 1 it can be seen that for the production of conversion pipes with a size of 426 × 23 mm according to the proposed technology, 5 hollow ingot blanks ESRs with a size of 600 × ext. 240 × 2100 ± 50 mm of supply from OAO ZMZ were used. ESW hollow ingots-blanks with a size of 600 × ext. 240 × 2100 ± 50 mm were heated and rolled at 8-16 ″ TPU into conversion pipes of 426 × 23 mm in size, in accordance with claims 1 to 4 of the claims. Hollow ingots-blanks for rolling pig tubes with a total weight of 19.662 tons were planted in a methodical furnace and heated in accordance with paragraphs 2 and 6 of the claims to a temperature of 1180-1200 ° C, stitched-rolled in a cross-helical mill in sleeves of size 6200 × ext. 415 × 2870-3000 mm on a mandrel with a diameter of 400 mm with a hood µ = 1.4 m diameter rise δ = 3.33%. The sleeves were rolled on a pilgrim mill to conversion pipes of 426 × 23 × 13900-14650 mm in size with an extract of μ = 5.72, a diameter reduction of Δ = 30.6% and feeds into the deformation zone of 16-18 mm. Technological waste - pilgrim heads and seed ends were cut off from pipes on a hot cutting saw. The pipes were straightened on a six-roll straightening machine, heat-treated, cut into two parts of equal length and sent to roll to the KhPT450 mill in commodity size 377 × 18 mm (in accordance with paragraphs 1, 3 and 4 of the claims). As a result of rolling the conversion pipes into commodity pipes, 10 pipes with a size of 377 × 18 × 9100-9700 mm were obtained, which were accepted with a tolerance of ± 1.0% in diameter and + 15 / -5.0 in the wall with a total weight of 15.746 tons (in accordance with claim 3 of the claims). The expenditure coefficient of the metal in the pipes of this batch was 1.249. For comparison, this pipe size was rolled according to the classical scheme from drilled EBP ingots-blanks measuring 565 × 100 × 1750 ± 50 mm with double heating, firmware, rolling-rolling, rolling on a pilgrim mill and subsequent rolling on the KhPT450 mill. The expenditure coefficient of the metal was 1.295.

Thus, the use of the proposed method will make it possible for the first time in Russia to produce seamless cold-rolled pipes of 377 × 14-19 mm in size from hot-rolled steel tubes of 426 × 21 and 426 × 23 mm in size, rolled at 8-16 ′ TPU with pilgrim mills from hollow ingots EShP of 10Kh9MFB-Sh grade steel for steam boilers, steam pipelines and manifolds of plants with high and supercritical steam parameters with mechanical properties of the metal and geometric pipe sizes exceeding the values of these indicators given in TU 14-3R-55-2 001, which will significantly reduce energy costs by eliminating the heating of ESR ingots-blanks for flashing and firmware-rolling, eliminating from the technological process of flashing ingots-blanks into blanks in the manufacture of conversion pipes, to produce high-quality conversion pipes on TPU 8-16 ″ with pilgrim mills of ChTPZ OJSC for the subsequent redistribution of the conversion pipes into commodity pipes by rolling them at the KhPT450 mill, to exclude mechanical processing from the technological process - turning and boring of conversion pipes into commodity size 377 × 14-19 mm, to increase the mechanical properties of the pipe metal by increasing the deformation during flashing-rolling of hollow ingots-blanks and subsequent rolling at the KhPT450 mill, and, therefore, to reduce the metal consumption when converting hollow ingots-blanks ESR into size 420 × 21 and 426 × 23 mm for their subsequent rolling on the KhPT450 mill into commodity pipes of 377 × 14-19 mm in size, to increase the productivity of TPU 8-16 ″ with pilgrim mills and reduce the cost of boiler pipes.

Claims (5)

1. Method for the production of seamless pipes 377 × 14-19 mm in size for steam boilers, steam pipelines and manifolds of plants with high and supercritical steam parameters from steel grade 10X9MFB-III, including ingots melting by electroslag remelting, turning and boring of ingots into hollow ingots of size 600 × ext. 240 × 2100 ± 50 mm, heating of ingot blanks to a temperature of 1180-1200 ° C, firmware-rolling of ingot blanks in a cross-helical rolling mill on a mandrel with a diameter of 400 mm in sleeves of 620 × ext. 415 × 2860 -3000 mm with a hood µ = 1.4 and a rise in diameter δ = 3, 3% and rolling on TPU 8-16 ″ with pilgrim mills into hot-rolled chimneys of sizes 426 × 21 × 15300-16200 and 426 × 23 × 13800-14700 mm with hoods, respectively, μ = 6.24 and μ = 5.72, compression by diameter of 30.6% and with feeds of sleeves into the deformation zone m = 16-19 mm, a segment of technological waste - seed ends and pilgrim heads with a hot cutting saw, straightening on a six-roll straightening machine, heat treatment, repair if necessary, cutting into two pipes of equal length and acceptance with a tolerance of + 1.25 / -1.0 in diameter and ± 12.5% wall thickness, cold rolling piece pipes-krat into commodity pipes measuring 377 × 14-19 mm. 2. The method according to claim 1, characterized in that the conversion pipe-krat of 426 × 21 × 7650-8100 mm in size is rolled on the KhPT450 mill into commodity cold-rolled pipes of 377 × 14 × 12550-13100, 377 × 15 × 11600-12300 and 377 × 16 × 10800-11500 mm with hoods, respectively, µ = 1.67, µ = 1.57 and µ = 1.47, and redistributing pipes-krates of 426 × 23 × 6900-7350 mm in size are rolled on the KhPT450 mill into commodity pipes 377 × 17 × 10100-10750, 377 × 18 × 9500-10100 and 377 × 19 × 9000-9600 mm in size with hoods, respectively µ = 1.52, µ = 1.43 and µ = 1.36, heat treatment is carried out, straightening, ultrasonic testing and acceptance of pipes with tolerances of ± 1.0% in diameter and wall thickness and + 15 / -5%. 3. The method according to claim 1 or 2, characterized in that the hot rolled tubes in the pilgrim mill are produced with total hoods from μ _Σ = 8.73 to μ _Σ = 8.01, and hot-rolled commodity tubes with total hoods from μ _Σ = 4.2 to μ _Σ = 3.08, commodity cold-rolled pipes with a size of 377 × 14-19 mm are produced with total hoods from $${\mu }_{\Sigma }^{\mathrm{one}}=14.58$$

before $${\mu }_{\Sigma }^{\mathrm{one}}=10.89$$

, lower values of which relate to pipes with lower D / S ratios and are determined from the expressions
µ _∑ = µ _sp. µ _p ,
$${\text{μ}}_{\text{Σ}}^{\text{one}}={\text{μ}}_{\text{Σ}}{\text{μ}}_{\text{x}}$$

,
where µ _ave. - hood with firmware rolling of hollow ingots-blanks into sleeves in a cross-helical rolling mill;
µ _p - hood during rolling of conversion and commodity pipes on a pilgrim mill;
µ _x - hood when rolling the conversion pipes into commodity pipes at the KhPT450 mill. 4. The method according to claim 1, characterized in that the hollow ingots of electroslag remelting for rolling pig tubes are cast with a ratio of diameter to wall thickness D / S = 5.2-5.3, and for rolling commodity pipes with a ratio of diameter to thickness walls D / S = 3.7-5.1, which are turned and bored into hollow ingots-blanks with a ratio of diameter to wall thickness, respectively, D / S = 5.9-6.0 and D / S = 3.7-5 , 1, the large values of which relate to hollow ingots and ingot billets for rolling hot-rolled and commodity hot-rolled tubes with smaller wall thicknesses. 5. The method according to claim 1, characterized in that the hollow ingots-billets are heated in a methodical furnace using the technology:
- ingots-blanks are planted on the furnace grates in batches of 8-10 pieces in a row with an interval of 1.25-1.5 hours at a temperature in the third zone of the furnace of 1000-1050 ° C;
- exposure of ingot blanks to grates without tilting for 1.0-1.25 hours;
- heating ingots blanks with a diameter of 600 mm with a ratio D / S = 5.9-6.0 at a speed of 2.5-2.9 ° C per minute for 4.5-5.0 hours to a temperature of 1180-1200 ° C with uniform pitching of ingot blanks along the bottom of the furnace from the 22nd to the 6th window in 18-20 minutes at an angle of 220-230 °,
- tilting from the 4th window to the furnace pit and delivery of billets from the furnace with the temperature of the center of the ingot-billets 1160-1200 ° C, large values of which relate to redistribution with a smaller wall thickness.