RU2617080C1 - Method of producing seamless machined pipes with 610x10-14 mm size from steel of "08х18н10т-ш" grade - Google Patents

Method of producing seamless machined pipes with 610x10-14 mm size from steel of "08х18н10т-ш" grade Download PDF

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RU2617080C1
RU2617080C1 RU2016110233A RU2016110233A RU2617080C1 RU 2617080 C1 RU2617080 C1 RU 2617080C1 RU 2016110233 A RU2016110233 A RU 2016110233A RU 2016110233 A RU2016110233 A RU 2016110233A RU 2617080 C1 RU2617080 C1 RU 2617080C1
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pipes
size
ingots
diameter
hot
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Анатолий Васильевич Сафьянов
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Комаров Андрей Ильич
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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B21MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21BROLLING OF METAL
    • B21B21/00Pilgrim-step tube-rolling, i.e. pilger mills

Abstract

FIELD: metallurgy.
SUBSTANCE: method includes machining: boring and turning of rerolled hot-rolled pipes rolled on TPU 8-16" with pilgrim mills from hollow ingots-billets of ESR. The process is carried out by regulating the billet parameters and processing modes at all production stages.
EFFECT: reduced metal consumption coefficient.
3 cl, 1 tbl

Description

The invention relates to pipe rolling and metallurgical industries, and in particular to a method for the production of seamless hot-deformed machined pipes of size 610 × 10-14 mm from steel grade 08X18H10T-Sh of high accuracy for nuclear power facilities.

In the pipe industry, a method is known for the production of seamless hot-formed mechanically machined pipes with a diameter of 530-550 mm from corrosion-resistant hard-deformed steel grades and alloys on TPU 8-16 '' with pilgrim mills, including casting ESR ingots 610 × 1725 ± 25 mm in size, machining - turning of ingots into ingots-blanks of size 590 ± 5.0 × 1725 mm, drilling in blanks-blanks of a central hole with a diameter of 100 ± 5.0 mm, boring of ingots-blanks to a size of 590 ± 5.0 × ext. 220 ± 5, 0 × 1750 ± 25 mm, heating ingots-blanks to tempera plasticity bores, piercing in a cross-helical rolling mill into billet sleeves measuring 620 × ext. 365 × 1950-2000 mm on a mandrel with a diameter of 350 mm with a diameter rise of δ = 4.0-6.0%, heating of the billets with cold or hot planting to a temperature of ductility, firmware - rolling in a mill of cross-helical rolling into sleeves of size 660 × 505-515 × 2950-3100 mm on a mandrel with a diameter of 490-500 mm with a diameter rise of δ = 5.5-6.5 %, rolling of sleeves on TPU 8-16 '' with pilgrim mills into conversion tubes with a diameter of 530-550 mm with a ratio D / S = 13.5-15.0 with an allowance for wall thickness under the fur initial processing - boring and turning, determining the thicknesses of the removed metal layers during turning and boring from the expressions Δ = D / S * K, Δ 1 = D / S * K 1 , where Δ is the thickness of the removed metal layer when turning hot rolled pipes along the outer surface, mm; Δ 1 - the thickness of the removed metal layer when boring hot rolled pipes on the inner surface, mm; D is the outer diameter of the hot rolled pipes, mm; S is the wall thickness of the hot rolled pipes, mm; K = 0.5-0.7 - coefficient for determining the thickness of the removed metal layer when turning pipes, large values of which apply to pipes with thicker walls; K 1 = 0.4-0.5 - coefficient for determining the thickness of the removed metal layer when boring pipes, large values of which relate to pipes with thicker walls (RF patent No. 2387501, publ. 07.27.2010, bull. No. 12).

The disadvantage of this method is that it solves the general issues of the production of seamless hot-deformed pipes from corrosion-resistant hard-deformed steel grades and alloys with a ratio of D / S = 13.5-15.0 for subsequent machining - boring and turning them into commodity pipes with a diameter of 530-550 mm with a wall thickness of more than 20 mm, a length of not more than 4700 mm and does not solve the technological issues of the production of limit and machined pipes for nuclear power facilities with a size of 610 × 10-14 mm from 08Kh18N10T-Sh steel increased accuracy in diameter and wall, namely with a tolerance of ± 0.8% in diameter and ± 10.0% in wall.

In world practice, on pipes rolling installations with pilgrim mills, pipes of size 610 × 10-14 mm of increased accuracy from 08Kh18N10T-Sh steel have not been produced and are not manufactured.

In the pipe industry, a method is known for producing seamless hot-formed mechanically machined pipes with a diameter of 273-550 mm from carbon steel 20 and alloy steels of grades 15GS, 15GS-Sh, 16GS, 16GS-Sh, 12Kh1MF and 15Kh1M1F for the production of parts and elements of pipelines of TPPs and NPPs using trepanation cylindrical forgings with subsequent boring and turning of a predetermined size with a purity of not lower than R z of 40 microns (TU 1310-030-00212179-2007 "seamless pipes Hot machined from carbon and alloy steels for tubes TPS wires and AES ").

The disadvantages of this method are the large expenditure coefficient of the metal (from 5.4 to 16.5), the value of which increases with decreasing wall thickness of the commodity pipes and increasing diameter, increased complexity and energy consumption associated with heating and forging ingots weighing more than 12 tons into cylindrical forgings of length up to 5.0 m, cutting off the end trim, trimming and turning of the forgings to a predetermined outer diameter, trepanation of forgings-blanks on unique equipment with subsequent boring with a surface finish of at least R z 40 μm and, as with consequence, increased cost of boiler pipes.

The closest technical solution (prototype) is a method for the production of seamless hot-deformed long pipes with a diameter of 500 mm or more on pipe rolling plants with pilgrim mills for steam boilers, steam pipelines and manifolds of plants with high and supercritical steam parameters (patent RU No. 232322315, class B21V 19 / 04, November 27, 2007), including the casting of hollow ingots by electroslag remelting with the ratio of diameter to wall thickness D / S = K 1 , H = K 2 D and H 1 = K 3 D, where D = 680 is the outer diameter of the hollow ingot of electroslag remelting mm; S is the wall thickness of the hollow ingot of electroslag remelting, mm; K 1 = (4.8–9.2) is a coefficient whose large values are taken for hollow ingots with a smaller wall thickness; H = (3000-3500) - the height of the hollow ingot of electroslag remelting for rolling pipes with a ratio of D / S≤20, mm; K 2 = (4.4-5.2) - the values of the coefficients for rolling pipes with a ratio of D / S≤20; H 1 = (2000-2100) - the height of the hollow ingot of electroslag remelting for rolling pipes with a ratio of D / S≤20, mm; K 3 = (2.9-3.1) - coefficient values for rolling pipes with a ratio of D / S≥20, mm, hollow ingots of electroslag remelting for rolling boiler pipes with a ratio of D / S≥20, cast with an inner diameter of D ext . = D d ± 5.0, where D d is the mandrel diameter, mm, electroslag remelting ingots for rolling boiler pipes are machined and bored into hollow ingots with metal removal of 8 ± 2.0 mm thick to remove welding slag and casting defects , hollow ingots-blanks of electroslag remelting are heated to the temperature of plasticity and rolled on a pilgrim mill into pipes with a ratio D / S≥20 with a tolerance of ± 1.0% in diameter and wall thickness + 15.0 / -10.0%, hollow ingots electroslag remelting for rolling boiler pipes with a ratio D / S≤20 cast wagons with an inner diameter of 300 ± 10 mm, which are turned and bored into hollow ingots-blanks with metal removal with a thickness of 8 ± 2.0 mm to remove welding slag and casting defects, hollow ingots-blanks of electroslag remelting are heated to ductility temperature, stitched - They are rolled in a cross-helical rolling mill into sleeves on a mandrel with a diameter larger than the mandrel diameter by 15-20 mm and rolled on a pilgrim mill in pipes with a ratio D / S≤20 with a tolerance of ± 1.0% in diameter and a wall thickness of +15.0 / -10.0%.

One of the main disadvantages of the bottom method is that it is aimed at the production of boiler pipes with a diameter of up to 550 mm and does not solve the technological issues of the production of pipes with a size of 610 × 10-14 mm from 08Kh18N10T-Sh steel for nuclear power facilities.

The disadvantages of this method are also: the dimensions of the hollow ingots ESR, which makes it difficult to determine the geometric dimensions of the hollow ingots-blanks for rolling pipes of the required size; the inner diameters of hollow ingots-billets, taking into account the removal of metal with a bore of 8 mm per side, have underestimated results, which when rolling thick-walled pipes leads to tightening mandrels; rolling of pipes with a wall thickness of more than 30 mm is associated with additional firmware - rolling of hollow ingots-billets in a cross-helical rolling mill, which with high probability can lead to increased curvature and difference in sleeves during uneven heating of ingots-billets in methodical furnaces, а, therefore, to the difference in the pipes.

The objective of the proposed method is the development and implementation of the technological process for the production of seamless hot-formed mechanically machined pipes with a size of 610 × 10-14 mm of increased accuracy in diameter and wall thickness from steel grade 08X18H10T-Sh for nuclear power facilities, reducing metal consumption during their production, and therefore , reducing their cost.

The technical result is achieved by the fact that the method for the production of seamless machined pipes with a size of 610 × 10-14 mm for nuclear facilities of steel grade 08Kh18N10-Sh includes: casting hollow ingots by electroslag remelting with a size of 740 × vn. 580 × 3200 ± 50 mm, boring and turning them into ingot blanks of 720 × ext. 600 × 3200 ± 50 mm in size, heating the ingot blanks in methodical furnaces to a temperature of 1260-1270 ° C, dispensing them to an ingot cart, blowing them with compressed air or an inert gas, feeding ingots into preparations from two ends of the lubricant in the form of a mixture graphite with table salt in a ratio of 50/50 weighing 2000-2500 g, feeding the hollow ingots-blanks with a crane to the inlet side of the pilgrim mill, rolling them on a pilgrim mill in a caliber of 640 mm with an angle of lateral outlet on the polishing section 24-26 °, cut into rolls with a barrel diameter of 1150 mm, into conversion pipes of 630 × 30 × 5300-5500 mm in size on cone mandrels with a diameter of 575/581 mm with drawing coefficients μ 2.16, diameter reduction Δ = 12.5% and with ingot feeding in the deformation zone m = 22-24 mm, in the segment of technological waste - seed ends and pilgrim x heads with a hot cutting saw, straightening on a six-roll straightening machine for 2-3 passes to a curvature of not more than 5.0 mm per length of a conversion pipe, heat treatment - austenization, machining - boring and turning of conversion pipes 630 × 30 × 5300-5500 mm into commodity sizes of 610 × 10-14 × 5300-5500 mm and they are accepted for compliance with the requirements of TU 14-3R-197-2001.

The machining of hot-rolled chimneys measuring 630 × 30 × 5300-5500 mm into commodity machined pipes is first performed on a size of 610 × 14 mm, then on a size of 610 × 13, 610 × 12, 610 × 11 and 610 × 10 mm.

In this case, the semantic value of the characteristic characterizing the diameter of the conical mandrels is 575/581 mm, it should be understood how the first of the indicated diameter values refers to the front section of the mandrel, and the second to its rear section.

A comparative analysis of the proposed solution with the prototype shows that the inventive method for the production of seamless machined pipes with a size of 610 × 10-14 mm for nuclear power facilities from steel grade 08X18H10T-Sh differs from the known one in that hollow ingots are cast using electroslag remelting with a size of 740 × int. 580 × 3200 ± 50 mm, boring and turning them into ingot blanks of 720 × ext. 600 × 3200 ± 50 mm in size, heating the ingot blanks in methodological furnaces to a temperature of 1260-1270 ° C, dispensing them to the ingot cart, blowing with compressed air or frost gas, lubricating ingots from the inside from both ends with a mixture of graphite with sodium chloride in a ratio of 50/50 weighing 2000-2500 g, rolling them on a pilgrim mill in a caliber of 640 mm, cut into rolls with a barrel diameter of 1150 mm with a lateral outlet angle of polishing section 24-26 °, with the ingot-billets being fed into the deformation zone m = 22-24 mm, into hot-rolled steel tubes measuring 630 × 30 × 5300-5500 mm with a diameter reduction of Δ = 12.5%, a piece of technological waste with a saw hot cutting, straightening on a six-roll straightening machine for 2-3 passes to curvature not more than 5.0 mm for the length of the conversion pipe, austenization, boring and turning of the conversion pipes of size 630 × 30 × 5300-5500 mm into commodity pipes of size 610 × 10-14 × 5300-5500 mm, hot-rolled conversion pipes of 630 × 30 × 5300-5500 mm, roll on a pilgrim mill on conical mandrels with a diameter of 575/581 mm with a drawing coefficient μ 2.16, and the machining of converted hot-rolled pipes of size 630 × 30 × 5300-5500 mm into commodity machined pipes is carried out first at a size of 610 × 14 mm, then sizes 610 × 13, 610 × 12, 610 × 11 and 610 × 10 mm.

Thus, these differences allow us to conclude that the criterion of "inventive step" is met.

For the first time in world practice, the method of producing seamless mechanically machined pipes of 610 × 10-14 mm in size for nuclear power facilities made of 08Kh18N10T-Sh steel was carried out according to the proposed technology in the production of pipes of 610 × 12 × 5400 mm in size by machining - boring and turning of hot rolled pipes of 630 × 30 × 5400 mm in size, rolled at 8-16 '' TPU with pilgrim mills of Chelyabinsk Pipe Rolling Plant OJSC from hollow ingot blanks ESR with a size of 720 × ext. 600 × 3200 mm. Since pipes of this assortment were not produced at TPU with pilgrim mills, comparative rolling was not carried out.

Two hollow ESR ingots-blanks with dimensions of 720 × ext. 600 × 3200 mm and a weight of 6.25 tons were put into production, which were heated in a methodical furnace to a temperature of 1260-1270 ° С. After issuing them to the ingot trolley, the ingot blanks were purged with compressed air. Lubrication of ingots-blanks was carried out by the task of a mixture of graphite with sodium chloride in a ratio of 50/50 weighing 1000-1250 g at each end. Then, the ingot blanks were supplied by crane to the inlet side of the pilgrim mill. Rolling on a pilgrim mill was performed in a caliber of 640 mm with a lateral angle of exit at a polishing section of 25 °, cut into rolls with a barrel diameter of 1150 mm, into conversion tubes 630 × 30 × 5400 mm in size on conical mandrels with a diameter of 575/581 mm with a drawing coefficient μ equal to 2.16, compression in diameter Δ = 12.5% and with the supply of ingots-blanks in the deformation zone m, equal to 22-24 mm After cutting off the technological waste - seed ends and pilgrim heads, straightening on a six-roll straightening machine was carried out in 2-3 passes using the temperature of the pipes from rolling heating. The curvature of the pipes after the correct machine was determined by eye. After cooling the pipes, the maximum curvature of the pipes ranged from 3.5 to 5.0 mm. After heat treatment - austenization, the pipes were bored, turned and adopted according to TU 14-3R-197-2001. Data on the production of seamless mechanically machined pipes measuring 610 × 12 × 5400 from steel grade 08X18H10T-Sh according to the proposed technology are shown in table 1.

Figure 00000001

The table shows that the expenditure coefficient of the metal in the production of pipes of size 610 × 12 × 5400 mm from hollow ingots-blanks of size 720 × ext. 600 × 3200 mm amounted to 3.272.

Thus, the use of the proposed method will allow for the first time in world practice at TPU 8-16 '' to carry out the production of hollow ingots-billets of 720 × ext. 600 × 3200 ± 50 mm in size conversion tubes 630 × 30 × 5400 mm in size for subsequent machining - boring and turning them into commodity seamless machined pipes with a diameter of 610 mm with wall thicknesses from 10 to 14 mm for nuclear power facilities. Pipes in geometric dimensions and surface quality fully meet the requirements of TU 14-3R-197-2001.

Claims (3)

1. Method for the production of seamless machined pipes with a size of 610 × 10-14 × 5300-5500 mm from steel grade 08X18H10T-Sh, including the casting of hollow ingots by electroslag remelting with a size of 740 × ext. 580 × 3200 ± 50 mm, boring and turning them into ingots - workpieces with a size of 720 × ext. 600 × 3200 ± 50, mm, heating ingots-blanks in methodical furnaces to a temperature of 1260-1270 ° C, dispensing them to an ingot cart, blowing them with compressed air or inert gas, feeding ingots from two ends of the lubricant in the form of a mixture of graphite with sodium chloride in a ratio of 50/50 weighing 2000-2500 g, proca them on a pilgrim mill in a caliber of 640 mm, cut into rolls with a barrel diameter of 1150 mm with an angle of lateral release on the polishing section of 24-26 °, with the supply of ingots-blanks to the deformation zone m = 22-24 mm, into hot rolled pipes in size 630 × 30 × 5300-5500 mm with a compression in diameter Δ = 12.5%, a piece of technological waste with a hot cutting saw, straightening on a six-roll straightening machine for 2-3 passes to the curvature of not more than 5.0 mm for the length of the transfer pipe, austenization , boring and turning of conversion pipes into commercial ones with a size of 610 × 10-14 × 5300-5500 mm.
2. The method according to p. 1, characterized in that the hot rolled steel tubes measuring 630 × 30 × 5300-5500 mm are rolled on a pilgrim mill on conical mandrels with a diameter of 575/581 mm with a drawing coefficient μ of 2.16.
3. The method according to p. 1, characterized in that the machining of the hot-rolled chimneys measuring 630 × 30 × 5300-5500 mm into commodity machined pipes is first made to a size of 610 × 14 mm, then to 610 × 13, 610 × 12 , 610 × 11 and 610 × 10 mm.
RU2016110233A 2016-03-22 2016-03-22 Method of producing seamless machined pipes with 610x10-14 mm size from steel of "08х18н10т-ш" grade RU2617080C1 (en)

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RU2017109105A Division RU2638265C1 (en) 2017-03-20 2017-03-20 METHOD OF PRODUCTION OF SEAMLESS MACHINED PIPES WITH SIZE OF 610×21-27 mm FROM STEEL OF 08Cr18N10T-S GRADE
RU2017109104A Division RU2638264C1 (en) 2017-03-20 2017-03-20 METHOD OF PRODUCTION OF SEAMLESS MACHINED PIPES WITH SIZE OF 610×15-20 mm FROM STEEL TO 08Cr18N10T-S GRADE

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4641513A (en) * 1983-08-01 1987-02-10 Vallourec Cold rolling process for tubes, by means of a Pilger rolling mill and the rolling mill for its execution
RU2175899C2 (en) * 1999-09-23 2001-11-20 Открытое акционерное общество "Челябинский трубопрокатный завод" Method for making tubes of hard-to-form kinds of steel
RU2322315C2 (en) * 2006-05-22 2008-04-20 ОАО "Челябинский трубопрокатный завод" Method for producing in tube rolling plants with pilger mills seamless hot-deformed elongated tubes for steam boilers, steam conduits and manifolds of plants with high and super-critical parameters of steam
RU2401169C2 (en) * 2008-04-18 2010-10-10 ОАО "Челябинский трубопрокатный завод" Method of producing high-quality pipes from antirust steel 08x18h10t-"+" for nuclear power engineering structures

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4641513A (en) * 1983-08-01 1987-02-10 Vallourec Cold rolling process for tubes, by means of a Pilger rolling mill and the rolling mill for its execution
RU2175899C2 (en) * 1999-09-23 2001-11-20 Открытое акционерное общество "Челябинский трубопрокатный завод" Method for making tubes of hard-to-form kinds of steel
RU2322315C2 (en) * 2006-05-22 2008-04-20 ОАО "Челябинский трубопрокатный завод" Method for producing in tube rolling plants with pilger mills seamless hot-deformed elongated tubes for steam boilers, steam conduits and manifolds of plants with high and super-critical parameters of steam
RU2401169C2 (en) * 2008-04-18 2010-10-10 ОАО "Челябинский трубопрокатный завод" Method of producing high-quality pipes from antirust steel 08x18h10t-"+" for nuclear power engineering structures

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