RU2550035C2 - Method of fabrication of seamless hot-rolled pipes 530(17-60, 550(25-60, 610(32-50 and 630(32-60 mm out of forged, continuously cast billets, ingots and hollow ingots of electroslag remelting process at pipe-rolling unit 8-16" with pilger mills of jsc chtpz - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: method includes drilling in the billets of the through hole with diameter 100±5 mm, heating to temperature of mouldability, piercing at the helical rolling mill to hollow thick-wall shells with rise along diameter, heating of thick-wall shells from cold or hot fit to temperature of mouldability, piercing-rolling at helical rolling mill of the thick-wall shells, rolling of thin-wall shells to said pipes at Pilger mills. Billets length for piercing is specified by the mathematical expression.

EFFECT: lower metal input, higher precision of pipe wall and diameter sizes.

4 cl, 1 tbl

Description

The invention relates to pipe production, in particular to a method for the production of seamless hot-rolled pipes of size 530 × 17-60, 550 × 25-60, 610 × 32-50 and 630 × 32-60 mm from forged, continuously cast billets, ingots and hollow ingots-billets of electroslag remelting in a tube mill with pilgrim mills made of carbon and low alloy steels, and can be used in the production of pipes of these sizes at TPU 8-16 ”of ChTPZ OJSC.

Known methods for the production of pipes with a diameter of 530-550 mm with a ratio of D / S≤21 on TPU 8-16 ”with pilgrim mills of ChTPZ OJSC from carbon and low-alloy steel grades and pipes with a diameter of 351 mm and more from ESR ingots of hardly deformable steel and alloy grades consisting in the fact that heated ingots and billets are stitched (deformed) in a cross-helical rolling mill into two firmwares (TI158-Tr. TB1-38-97 "Production of seamless hot-rolled pipes for steam boilers and pipelines according to TU14-3-460- 75 and TU14-3-420-75 ", TI158-Tr. TB1-56-97" Production of seamless hot-rolled steel pipes of grade 20 steel for the oil refining industry according to TU 14-3-587-77 ", TI15 8-Tr. TB1-51-2002" Production of seamless hot-rolled pipes from steel 15X5M according to TU14-3R-62-2002 "and TI158- Tr. TB1-53-2002 "Production of seamless hot-rolled pipes from corrosion-resistant steel grades with high surface quality according to TU14-3R-197-2001").

The disadvantage of these methods is that double flashing of ingots and billets (flashing in a cross-helical mill in thick-walled sleeves + reheating + flashing-rolling of thick-walled sleeves in a cross-helical rolling mill in thin-walled sleeves) is performed without considering the technological capabilities of the cross-section mill screw rolling and pilgrim mills, i.e. the maximum possible length of thick-walled sleeves, which can be set in the mill for rolling-rolling, the maximum diameter of thin-walled sleeves, which can be issued from a cross-screw mill, and the maximum length of sleeves, which can be rolled on a pilgrim mill without crushing the front end of the pipe, which leads to increase the share of technological waste (mass of pilgrim heads and seed ends). Flashing-rolling of sleeves on mandrels with a diameter of 500 mm or more with a ratio D / S≥10 leads to their uneven cooling in the cross-helical rolling mill and increased curvature, which in turn leads to an increased difference in pipes on the pilgrim mill and, as a result, to increased consumption of metal during redistribution (ingot-billet) - finished pipe. The main disadvantage of this method is that it does not provide for the production of pipes with a diameter of 610 and 630 mm, which the boiler-makers buy abroad or produce forged and trephined forged blanks.

In the pipe industry, a method for producing seamless hot-deformed pipes is known, which consists in heating billets to a temperature of ductility, flashing into thick-walled hollow sleeves in one cross-helical rolling mill, followed by rolling into thin-walled sleeves in a second cross-helical rolling mill and rolling them into large-diameter pipes in installations with an automatic mill (production of seamless pipes from corrosion-resistant steels according to GOST 9940-81 at TPA "350" of the Nikopol South Pipe Plant, Ukraine).

However, the known method has the following disadvantages. The practice of operation of cross-helical rolling mills shows that when piercing ingots and billets with uneven heating, we get thick-walled sleeves with increased curvature, rolling them into thin-walled sleeves in the second mill without heating leads to an increase in the initial curvature and, as a consequence, to increased transverse and longitudinal the difference of the pipes when rolling them at a injection molding machine with automatic mills, to the increased lateral difference when rolling them into pipes at the plants with pilgrim mills. This method is mainly intended for the production of pipes from hard-to-deform grades of steel and alloys with a diameter of up to 325 mm and does not solve the problems of the production of pipes with a diameter of 530, 550, 610 and 630 mm in tube rolling plants with pilgrim mills.

The closest technical solution is a method for producing seamless hot-deformed large-diameter pipes, including heating ingots and billets to a ductile temperature, flashing them into hollow thick-walled sleeves in one cross-helical rolling mill, followed by rolling into thin-walled sleeves in a second cross-helical rolling mill and rolling sleeves into large-diameter pipes in installations with automatic or pilgrim mills, while the ingots and billets are flashed into thick-walled sleeves t in the first mill of helical rolling, the work rolls of which rotate in one direction, and rolling into thin-walled sleeves in the second mill, the work rolls of which rotate in the opposite direction (RF patent No. 2243837, CL B21B 21/00, 01/10/2005) .

The disadvantage of this invention is that it is aimed at reducing the curvature of the sleeves, i.e. to improve the geometric dimensions of pipes, it requires a radical reconstruction of TPU with pilrigim mills and does not solve the technological issues of the production of pipes with a diameter of 530, 550, 610 and 630 mm on the existing TPU 8-16 ”with pilgrim mills.

The objective of the proposed method is the development of the production of pipes with a diameter of 610 and 630 mm on existing equipment TPU 8-16 ”with piligim mills, increasing the length of the pipes, improving the geometric dimensions of pipes with a diameter of 530, 550, 610 and 630 mm, reducing the expenditure coefficient of the metal and increasing the productivity of the tube installations due to theoretically substantiated geometric dimensions of forged, continuously cast billets (NLZ), ingot billets and hollow ingot billets of electroslag remelting (ESR), geometric dimensions t thick-walled and thin-walled sleeves, technological parameters for flashing thick-walled sleeves, firmware-rolling of thin-walled sleeves and tube rolling.

где L_г≤2100 - максимальная длина толстостенной гильзы, которую можно задать в стан поперечно-винтовой прокатки на повторную прошивку-раскатку, мм; D_г - наружный диаметр толстостенной гильзы, мм; S_г - толщина стенки толстостенной гильзы, мм; D_заг - диаметр кованой, непрерывно-литой заготовки или слитка-заготовки электрошлакового переплава, мм; S_заг - толщина стенки сверленых кованой, непрерывно-литой заготовки или слитка-заготовки электрошлакового переплава, мм; K - коэффициент, учитывающий угар металла при нагреве кованых, непрерывно-литых заготовок или слитков-заготовок электрошлакового переплава под прошивку, длину тонкостенных гильз определяют из выражения $$L_{т.г}=\frac{L_{г}\left(D_{г}-S_{г}\right)S_{г}{K}_1}{\left(D_{т.г}-S_{т.г}\right)S_{т.г}}\le L_{пред},$$

где D_т.г=690 - максимальный наружный диаметр тонкостенной гильзы, которую можно прошить-раскатать в стане поперечно-винтовой прокатки, мм; S_т.г - толщина стенки тонкостенной гильзы после раскатки толстостенной гильзы в стане поперечно-винтовой прокатки, мм; K₁ - коэффициент, учитывающий угар металла при нагреве толстостенных гильз до температуры пластичности под прошивку-раскатку в стане поперечно-винтовой прокатки; L_пред≤3400 - максимальная длина тонкостенной гильзы, которую можно задать в пилигримовый стан без смятия переднего конца трубы, мм, длину полых слитков-заготовок электрошлакового переплава определяют из выражения L_п.г.з≤3400 мм, прошивку кованых, непрерывно-литых заготовок и слитков-заготовок электрошлакового переплава в стане поперечно-винтовой прокатки в полые толстостенные гильзы для прокатки труб диаметром 530 мм производят с подъемом по диаметру от 4,8 до 6,7%, а труб диаметром 550 мм с подъемом по диаметру от 3,1 до 6,7%, большие значения которых относятся к трубам с меньшей толщиной стенки, трубы диаметром 530 и 550 мм производят из кованых, непрерывно-литых заготовок и слитков-заготовок электрошлакового переплава, а трубы диаметром 610 и 630 мм из полых слитков-заготовок электрошлакового переплава, кованые, непрерывно-литые заготовки и слитки-заготовки электрошлакового переплава длиной до 1800 мм садят в методические печи в два ряда, а кованые, непрерывно-литые заготовки, слитки-заготовки электрошлакового переплава и полые слитки электрошлакового переплава длиной более 1800 мм садят в методические печи в один ряд, прокатку труб диаметром 530, 550, 610 и 630 мм на пилигримовом стане производят с подачами гильз в очаг деформации пилигримового стана, значения которых определяют из выражений m+1=D/S-3, m+1=D/S где m=18 - величина подачи гильзы в очаг деформации пилигримового стана при прокатке труб размером 530×17 и 550×25 мм, мм; m₁=15 - величина подачи гильзы или полого слитка-заготовки электрошлакового переплава в очаг деформации пилигримового стана при прокатке труб размером 610×32 и 630×32 мм.The technical result is achieved by the fact that in the known method for the production of seamless hot-rolled pipes of size 530 × 17-60, 550 × 25-60, 610 × 32-50 and 630 × 32-60 mm from forged, continuously cast billets, ingots, and hollow ingots-billets of electroslag remelting in an 8-16 ”tube rolling system with Pilgrim mills of ChTPZ OJSC, including drilling in forged, continuously cast billets and ingots-blanks of electroslag remelting of a through hole with a diameter of 100 ± 5 mm, heating forged, continuously cast blanks, ingot blanks and floors electroslag remelting ingot billets to ductility temperature, forged, continuously cast billets and electroslag ingot billet piercing in cross-helical rolling mill in hollow thick-walled sleeves with a diameter increase of 3.2 and 5.0%, heating of thick-walled sleeves with cold or hot planting to a temperature of ductility, firmware rolling in a cross-helical rolling mill of thick-walled shells into thin-walled shells, rolling of thin-walled shells and hollow ingots-blanks of electroslag remelting into pipes on pilgrim mills, the length of the forged, continuously cast billets and ingots-blanks electroslag remelting is determined from the expression $$L_{s\mathrm{but}g}=\frac{L_g\left(D_g-S_g\right)S_g}{K\left(D_{s\mathrm{but}g}-S_{s\mathrm{but}g}\right)S_{s\mathrm{but}g}},$$

where L _g ≤2100 is the maximum length of a thick-walled liner that can be set in the cross-helical rolling mill for re-flashing, mm; D _g - the outer diameter of a thick-walled sleeve, mm; S _g - wall thickness of a thick-walled sleeve, mm; D _zag - diameter of forged, continuously cast billet or ingot-billet of electroslag remelting, mm; S _zag is the wall thickness of the forged, continuously cast billet or ingot-billet of electroslag remelting, mm; K is a coefficient that takes into account the burning of metal when heating forged, continuously cast billets or ingots-billets of electroslag remelting for firmware, the length of thin-walled sleeves is determined from the expression $$L_{t.g}=\frac{L_g\left(D_g-S_g\right)S_g{K}_{\mathrm{one}}}{\left(D_{t.g}-S_{t.g}\right)S_{t.g}}\le L_{PRed},$$

where D _tg = 690 - the maximum outer diameter of a thin-walled sleeve that can be flashed-rolled in a cross-helical rolling mill, mm; S _tg - wall thickness of a thin-walled sleeve after rolling a thick-walled sleeve in a cross-helical rolling mill, mm; K ₁ - coefficient taking into account the fume of metal when heating thick-walled sleeves to a temperature of plasticity for firmware-rolling in a cross-helical rolling mill; L _before ≤3400 - the maximum length of a thin-walled sleeve that can be set into a pilgrim mill without crushing the front end of the pipe, mm, the length of hollow ingots-blanks of electroslag remelting is determined from the expression L _P.G.z ≤3400 mm, firmware forged, continuously cast billets and ingots-billets of electroslag remelting in a cross-helical rolling mill into hollow thick-walled sleeves for rolling pipes with a diameter of 530 mm are produced with a rise in diameter from 4.8 to 6.7%, and pipes with a diameter of 550 mm with a rise in diameter from 3, 1 to 6.7%, large values of which s belong to pipes with a smaller wall thickness, pipes with a diameter of 530 and 550 mm are made from forged, continuously cast billets and electroslag remelting ingots, and pipes with a diameter of 610 and 630 mm from hollow ingots of electroslag remelting, forged, continuously cast billets and ingots-billets of electroslag remelting up to 1800 mm long are planted in two rows in method furnaces, and forged, continuously cast billets, ingots-billets of electroslag remelting and hollow ingots of electroslag remelting more than 1800 mm long are planted methodical furnaces in one row, rolling pipes with a diameter of 530, 550, 610 and 630 mm on a pilgrim mill is carried out with feeds of sleeves into the deformation zone of the pilgrim mill, the values of which are determined from the expressions m + 1 = D / S-3, m + 1 = D / S where m = 18 is the feed rate of the sleeve into the deformation zone of the pilgrim mill during rolling of pipes 530 × 17 and 550 × 25 mm in size; m ₁ = 15 is the feed rate of the sleeve or hollow ingot-billet of electroslag remelting into the deformation zone of the pilgrim mill during rolling of pipes 610 × 32 and 630 × 32 mm in size.

где L_г≤2100 - максимальная длина толстостенной гильзы, которую можно задать в стан поперечно-винтовой прокатки на повторную прошивку-раскатку, мм; D_г - наружный диаметр толстостенной гильзы, мм; S_г - толщина стенки толстостенной гильзы, мм; D_заг - диаметр кованой, непрерывно-литой заготовки или слитка-заготовки электрошлакового переплава, мм; S_заг - толщина стенки сверленых кованой, непрерывно-литой заготовки или слитка-заготовки электрошлакового переплава, мм; K - коэффициент, учитывающий угар металла при нагреве кованых, непрерывно-литых заготовок или слитков-заготовок электрошлакового переплава под прошивку, длину тонкостенных гильз определяют из выражения $$L_{т.г}=\frac{L_{г}\left(D_{г}-S_{г}\right)S_{г}{K}_1}{\left(D_{т.г}-S_{т.г}\right)S_{т.г}}\le L_{пред},$$

где D_т.г=690 - максимальный наружный диаметр тонкостенной гильзы, которую можно прошить-раскатать в стане поперечно-винтовой прокатки, мм; S_т.г - толщина стенки тонкостенной гильзы после раскатки толстостенной гильзы в стане поперечно-винтовой прокатки, мм; K₁ - коэффициент, учитывающий угар металла при нагреве толстостенных гильз до температуры пластичности под прошивку-раскатку в стане поперечно-винтовой прокатки; L_пред≤3400 - максимальная длина тонкостенной гильзы, которую можно задать в пилигримовый стан без смятия переднего конца трубы, мм, длину полых слитков-заготовок электрошлакового переплава определяют из выражения L_п.г.з≤3400 мм, прошивку кованых, непрерывно-литых заготовок и слитков-заготовок электрошлакового переплава в стане поперечно-винтовой прокатки в полые толстостенные гильзы для прокатки труб диаметром 530 мм производят с подъемом по диаметру от 4,8 до 6,7%, а труб диаметром 550 мм с подъемом по диаметру от 3,1 до 6,7%, большие значения которых относятся к трубам с меньшей толщиной стенки, трубы диаметром 530 и 550 мм производят из кованых, непрерывно-литых заготовок и слитков-заготовок электрошлакового переплава, а трубы диаметром 610 и 630 мм из полых слитков-заготовок электрошлакового переплава, кованые, непрерывно-литые заготовки и слитки-заготовки электрошлакового переплава длиной до 1800 мм садят в методические печи в два ряда, а кованые, непрерывно-литые заготовки, слитки-заготовки электрошлакового переплава и полые слитки электрошлакового переплава длиной более 1800 мм садят в методические печи в один ряд, прокатку труб диаметром 530, 550, 610 и 630 мм на пилигримовом стане производят с подачами гильз в очаг деформации пилигримового стана, значения которых определяют из выражений m+1=D/S-3, m₁+1=D/S, где m=18 - величина подачи гильзы в очаг деформации пилигримового стана при прокатке труб размером 530×17 и 550×25 мм, мм; m₁=15 - величина подачи гильзы или полого слитка-заготовки электрошлакового переплава в очаг деформации пилигримового стана при прокатке труб размером 610×32 и 630×32 мм, мм. Эти отличия позволяют сделать вывод о соответствии критерию "изобретательский уровень".A comparative analysis of the proposed solution with the prototype shows that the claimed method differs from the known one in that the length of the forged, continuously cast billets and ingots-billets of electroslag remelting is determined from the expression $$L_{s\mathrm{but}g}=\frac{L_g\left(D_g-S_g\right)S_g}{K\left(D_{s\mathrm{but}g}-S_{s\mathrm{but}g}\right)S_{s\mathrm{but}g}},$$

where L _g ≤2100 is the maximum length of a thick-walled liner that can be set in the cross-helical rolling mill for re-flashing, mm; D _g - the outer diameter of a thick-walled sleeve, mm; S _g - wall thickness of a thick-walled sleeve, mm; D _zag - diameter of forged, continuously cast billet or ingot-billet of electroslag remelting, mm; S _zag is the wall thickness of the forged, continuously cast billet or ingot-billet of electroslag remelting, mm; K is a coefficient that takes into account the burning of metal when heating forged, continuously cast billets or ingots-billets of electroslag remelting for firmware, the length of thin-walled sleeves is determined from the expression $$L_{t.g}=\frac{L_g\left(D_g-S_g\right)S_g{K}_{\mathrm{one}}}{\left(D_{t.g}-S_{t.g}\right)S_{t.g}}\le L_{PRed},$$

where D _tg = 690 - the maximum outer diameter of a thin-walled sleeve that can be flashed-rolled in a cross-helical rolling mill, mm; S _tg - wall thickness of a thin-walled sleeve after rolling a thick-walled sleeve in a cross-helical rolling mill, mm; K ₁ - coefficient taking into account the fume of metal when heating thick-walled sleeves to a temperature of plasticity for firmware-rolling in a cross-helical rolling mill; L _before ≤3400 - the maximum length of a thin-walled sleeve that can be set into a pilgrim mill without crushing the front end of the pipe, mm, the length of hollow ingots-blanks of electroslag remelting is determined from the expression L _P.G.z ≤3400 mm, firmware forged, continuously cast billets and ingots-billets of electroslag remelting in a cross-helical rolling mill into hollow thick-walled sleeves for rolling pipes with a diameter of 530 mm are produced with a rise in diameter from 4.8 to 6.7%, and pipes with a diameter of 550 mm with a rise in diameter from 3, 1 to 6.7%, large values of which s belong to pipes with a smaller wall thickness, pipes with a diameter of 530 and 550 mm are made from forged, continuously cast billets and electroslag remelting ingots, and pipes with a diameter of 610 and 630 mm from hollow ingots of electroslag remelting, forged, continuously cast billets and ingots-billets of electroslag remelting up to 1800 mm long are planted in two rows in method furnaces, and forged, continuously cast billets, ingots-billets of electroslag remelting and hollow ingots of electroslag remelting more than 1800 mm long are planted methodical furnace in a row, the rolling diameter pipes 530, 550, 610 and 630 mm in pilger made applying liners in hearth pilger deformation, values are determined from the expression m + 1 = D / S-3, m ₁ + 1 = D / S, where m = 18 is the feed rate of the sleeve into the deformation zone of the pilgrim mill during rolling of pipes 530 × 17 and 550 × 25 mm in size; m ₁ = 15 is the feed rate of the sleeve or hollow ingot-billet of electroslag remelting into the deformation zone of the pilgrim mill during rolling of pipes 610 × 32 and 630 × 32 mm, mm. These differences allow us to conclude that the criterion of "inventive step".

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 the patentability "inventive step".

The method has been tested and implemented at TPU 8-16 ”of ChTPZ OJSC in the production of boiler pipes 530 × 17 mm in size from forged billets and boiler pipes 610 × 32 mm in accordance with TU 14-3R-55-2001 from 15GS steel hollow ingots .

According to the existing technology, in the production of pipes with a size of 530 × 17 mm, 5 workpieces with a size of 1600 ± 25 mm were set into production, which were drilled to a diameter of 100 ± 5 mm, heated in a methodical furnace to a temperature of 1275-1280 ° C, stitched in a mill transversely screw rolling on a mandrel with a diameter of 300 mm with a rise in diameter of Δ = 3.2% and a hood µ = 1,161 into thick-walled sleeves measuring 650 × ext. 315 × 1830-1870 mm. Thick-walled liners from a cold embankment were heated in a methodical furnace to a temperature of 1280-1285 ° C, stitched-rolled in a cross-helical rolling mill on a mandrel with a diameter of 525 mm with a diameter rise of Δ = 4.6% and a hood µ = 1,836 into thin-walled sleeves 680 × in. 540 × 1830 × 3360-3430 mm. The sleeves on the pilgrim mill were rolled into pipes 530 × 17 × 13000-13500 mm in size, which were cut into two equal parts by a hot cutting saw, passed heat treatment, etching, bleaching, ultrasonic testing and were accepted for compliance with the requirements of TU 14-3R-55 -2001. 19.1 tons of metal were set into production. Accepted 14,243 tons of pipes. The expenditure coefficient of the metal was 1.341.

When rolling pipes of this size according to the proposed technology, in accordance with claim 1, the size of the workpieces was determined, which can be set in the cross-helical rolling mill so that the length of the thick-walled sleeve does not exceed 2100 mm. Then, in accordance with paragraph 2 of the claims, the correctness of the selected workpiece length and the length of the thick-walled sleeve was verified so that the length of the thin-walled sleeve did not exceed 3400 ± 50 mm. After performing these operations, the length of the workpiece was 1825 ± 25 mm. Five workpieces with a size of 1825 ± 25 mm were set into production, which were drilled to a diameter of 100 ± 5 mm, heated to a temperature of 1280-1285 ° C in a methodical furnace, stitched in a cross-helical rolling mill on a mandrel with a diameter of 300 mm with a rise in diameter Δ = 4.8% and a hood µ = 1,116 (claim 4 of the claims) in thick-walled sleeves measuring 660 × ext. 315 × 2010-2160 mm. Thick-walled sleeves from a cold embankment were heated in a methodical furnace to a temperature of 1270-1280 ° C, stitched-rolled in a cross-helical mill on a mandrel with a diameter of 515 mm with a diameter rise of Δ = 4.6% and a hood µ = 1,672 in thin-walled sleeves size 690 × ext. 530 × 3360-3450 mm (claim 2). The sleeves on the pilgrim mill were rolled into pipes 530 × 17 × 16100-16600 mm in size with the sleeves fed into the deformation zone 18 mm (claim 7), which were cut into two equal parts by a hot cutting saw, heat treated, etched, clarification, ultrasonic testing and accepted for compliance with the requirements of TU 14-3R-55-2001. 22.888 tons of metal were set into production. Accepted 18,473 tons of pipes. The expenditure coefficient of the metal was 1.239. When rolling pipes of this size according to the proposed technology, a decrease in the expenditure coefficient of the metal by 102 kg was obtained for each ton of pipes.

It was not possible to carry out rolling of pipes measuring 610 × 32 mm using the existing technology, because with the size of the forged workpiece 650 × 100 × 1125 ± 25 mm, we obtain a thin-walled sleeve with a size of 690 × ext. 590 × 3320-3480 mm. For transportation of heated billets along the transport conveyor, their length should not be less than 1240 mm.

For rolling pipes of this size according to the proposed method, 5 hollow ESR ingots-blanks with a size of 720 × ext. 570 × 3375 ± 25 mm were specified in production (claim 3 of the claims). Hollow ingots-billets were heated to a temperature of 1275-1280 ° C, issued from the furnace and transferred by crane to the inlet side of the pilgrim mill. Hollow ingots-blanks were rolled on a pilgrim mill on mandrels with a diameter of 551/552 mm with a feed of 15 mm into the deformation zone (paragraph 7 of the claims) into pipes of 610 × 32 × 7000-7100 mm in size. Pipes passed heat treatment, etching, clarification, ultrasonic testing and are accepted for compliance with the requirements of TU 14-3R-55-2001. 20,123 tons of hollow ingots-blanks ESR were set into production. 16,072 tons of pipes delivered. The expenditure coefficient of the metal in the pipes of this batch was 1.252.

The data on rolling pipes 530 × 17 mm in size from forged billets and pipes 610 × 32 mm in size from hollow ingots of ESR steel of grade 15GS according to TU 14-3R-55-2001 according to the existing and proposed technologies are given in Table 1.

Thus, according to the results of the experiment, for the first time in world practice, TPU 8-16 ″ produced high-quality pipes with a size of 610 × 32 mm, the theoretical justifications for the method of production of seamless hot-rolled pipes of 530 × 17-60, 550 × 25-60, 610 × 32 were confirmed -50 and 630 × 32-60 mm from forged, continuously cast billets, ingot billets and hollow ingot billets of electroslag remelting in an 8-16 ”tube rolling mill with Pilgrim mills of ChTPZ OJSC, increasing pipe lengths, improving pipe geometric dimensions reduction in expenditure ratios cient metal.

Using the proposed method for the production of seamless hot-rolled pipes of sizes 530 × 17-60, 550 × 25-60, 610 × 32-50 and 630 × 32-60 mm at TPU 8-16 ”with pilgrim mills of OAO ChTPZ will allow to master the production of pipes with a diameter 610 and 630 mm, significantly reduce metal consumption due to theoretically and technically sound geometric dimensions of forged, continuously cast billets (NLZ), ingot blanks and hollow ingot blanks of electroslag remelting (ESR), geometric dimensions of thick-walled and thin-walled, sleeves, technological parameters about ivki thick, EEPROM-rolling thin-walled sleeves and rolling tube, reduce the proportion of waste processing, according to variation in the waste pipe and rolling with tighter tolerances for the wall and, consequently, reduce the cost of the commodity pipe gauge.

Claims (4)

1. Method for the production of seamless hot-rolled pipes 530 × 17-60, 550 × 25-60, 610 × 32-50 and 630 × 32-60 mm in size on an 8-16 '' tube mill with pilgrim mills, including drilling in through hole billets with a diameter of 100 ± 5 mm, heating to ductility temperature, piercing in a cross-helical mill into hollow thick-walled sleeves with a rise in diameter, heating thick-walled sleeves from cold or hot surround to plasticity, piercing-rolling in a cross-helical rolling mill of thick-walled sleeves into thin-walled sleeves, rolling thin-walled sleeves into said pipes on pilgrim mills, characterized in that the length of the blanks for firmware is determined from the expression:
$$L_{s\mathrm{but}g}=\frac{L_g\left(D_g-S_g\right)S_g}{K\left(D_{s\mathrm{but}g}-S_{s\mathrm{but}g}\right)S_{s\mathrm{but}g}},$$

where L _g ≤2100 is the maximum length of a thick-walled liner that can be set in the cross-helical rolling mill for firmware rolling, mm;
D _g - the outer diameter of a thick-walled sleeve, mm;
S _g - wall thickness of a thick-walled sleeve, mm;
D _zag - diameter of the workpiece, mm;
S _zag - wall thickness of the drilled workpiece, mm;
K is the coefficient of burning metal when heating the workpieces for firmware,
and the length of the thin-walled sleeves for the production of these pipes is determined from the expression:
$$L_{t.g}=\frac{L_g\left(D_g-S_g\right)S_g{K}_{\mathrm{one}}}{\left(D_{t.g}-S_{t.g}\right)S_{t.g}}\le L_{PRed},$$

where D _tg = 690 - the maximum outer diameter of a thin-walled sleeve that can be flashed-rolled in a cross-helical rolling mill, mm;
S _tg - wall thickness of a thin-walled sleeve after flashing-rolling a thick-walled sleeve in a cross-helical rolling mill, mm;
K ₁ - the coefficient of burning metal when heating thick-walled sleeves to a temperature of plasticity under firmware rolling;
L _before ≤3400 mm - the maximum length of a thin-walled sleeve that can be set in a pilgrim mill without crushing the front end of the pipe, mm. 2. The method according to claim 1, characterized in that the piercing of the blanks in hollow thick-walled sleeves for rolling pipes with a diameter of 530 mm is carried out with a rise in diameter from 4.8 to 6.7%, and for rolling pipes with a diameter of 550 mm - with a rise in diameter from 3.1 to 6.7%, large values of which apply to pipes with a smaller wall thickness. 3. The method according to claim 1, characterized in that the workpieces with a length of up to 1800 mm are placed in a methodical furnace in two rows, and the workpieces with a length of more than 1800 mm are placed in one row. 4. The method according to claim 1, characterized in that on the pilgrim mill the rolling of pipes with a diameter of 530 and 550 mm is carried out with feeds of sleeves into the deformation zone, constituting 18 mm, and rolling of pipes with a diameter of 610 and 630 mm - with feeds of sleeves into the deformation zone, components 15 mm