RU2547760C1 - PRODUCTION OF "TURNKEY" 255×5,0+1,5/-1,0×4300+80/-30 mm HEXAGONAL PIPE-BILLETS - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to metallurgy. Ingots are cast by ESR process to size of 480×1800±25 mm. They are turned to ingots-billets sized to 465±5.0×1800±25 mm and central through 100±5 mm-dia hole is drilled. Said ingots-billets are heated to 1040-1050°C. Then, they are pierced at helical rolling mill to 460×ID290×2820-2900 mm sleeves with diameter reduction Δ of 0 to 2.2% and rolling-out µ_red. of 1.59 to 1.61. Said sleeves are rolled at Pilger mill to rerolled pipe sets sized to 287×11×25500-27000 mm with rolling-out Δ_r=10.50 and diameter reduction Δ=37.4%. Pipe sets are cut by saw to equal-size 10200-10500 mm-long lengths. Said pipes are straightened and cut to equal lengths. The latter are turned and bored to 281.1±2.0×5+1.5/-1.0 cylindrical pipes and heat-shaped to preset-size hexagonal pipe-billets.

EFFECT: decreased metal consumption factor.

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Description

The invention relates to pipe production, in particular to a method for the production of turnkey hexagonal tube blanks of 255 ± 2.0 × 5.0 + 1.5 / -1.0 × 4300 + 80 / -30 mm for storage and transportation spent nuclear fuel from low-ductility steel 04Kh14T5R2F-Sh with boron content from 2.0 to 3.0%, and can be used on TPU 8-16 ″ with pilgrim mills of ChTPZ OJSC in the production of seamless hot-rolled conversion tubes of 287 × 11 × 25500-27000 mm for their subsequent redistribution into hexagonal pipe blanks with a turnkey size of 255 ± 2.0 × 5.0 + 1.5 / -1.0 × 4300 + 80 / -30 mm.

In pipe production, there is a known method for the production of sheathing hexagonal tube blanks from boron-containing steel for compacted storage and transportation of spent nuclear fuel, which includes casting ingots by electroslag remelting from boron-containing steel, turning them on the outer surface to remove casting defects into ingots, and drilling a central hole diameter 100 ± 5 mm, heating ingot blanks, piercing ingot blanks in a cross-helical rolling mill into sleeves, rolling sleeves at to a grill mill into conversion lash pipes measuring 290 × 12 × 22000-23000 mm, cutting lashes into pipes of multiple lengths, straightening, cutting multiple pipes into slab pipes, boring and turning them into cylindrical billet pipes and warm profiling into hexagonal billet pipes measuring 257 + 2.0 / -3.0 × 6 + 2.0 / -1.0 × 4300 + 80 / -30 mm (patent RU No. 2317865, B21B 21/04, 02.27.2008).

The disadvantage of this method, which is intended for the production of hexagonal billets of size 257 + 2.0 / -3.0 × 6 + 2.0 / -1.0 × 4300 + 80 / -30 mm with a boron content of 1.3-1 , 8%, it is impossible to use it for the production of pipes from less ductile steel 04X14T5R2F-Sh with a boron content of 2.0 to 3.0%, since the well-known sequence of technological operations and processing modes do not allow obtaining billet pipes of the required quality.

The closest in technical essence is a method for the production of hexagonal billets of "turnkey" size 257 + 2.0 / -3.0 × 6.0-2.0 / -1.0 × 4300 + 80 / -30 mm for storage and transportation of spent nuclear fuel from conversion pipes of 290 × 12 × 25500-27500 mm in size, including casting ingots of 510 × 1725 ± 25 mm in size by electroslag remelting from low-ductility steel 04X14T5R2F-Sh with boron content from 2.0 to 3.0%, turning them on the outer surface into ingot blanks of size 485 ± 5 × 1725 ± 25 mm, drilling a through central hole with a diameter of 100 ± 5 mm, heating is drained ov-blanks to a temperature of 1040-1060 ° C, piercing ingot-blanks in a cross-helical rolling mill into sleeves of size 460 × ext. 295 × 2940-3000 mm with compression in diameter Δ from 4.2 to 6.1% and an exhaust hood μ from 1.73 to 1.81, rolling the sleeves on a pilgrim mill into a whip pipe size 290 × 12 × 25500-27500 mm with a hood μ = 9.34 and diameter reduction Δ = 36.5%, pipe cutting - lashes with a hot cutting saw for pipes with a length of 10100-10500 mm and the remainder, straightening the pipes, cutting pipes into slab pipes of 5050-5250 mm in size, boring and turning them into round billet pipes of 284.75 + 2.0 / -3 in size, 0 × 6.0 + 2.0 / -1.0 mm and warm p profiling into hexagonal billets of turnkey size 257 + 2.0 / -3.0 × 6.0 + 2.0 / -1.0 × 4300 + 80 / -30 mm (patent RU No. 2470723, B21B 21 21/00, 12/27/2012).

One of the main disadvantages of this prototype, as well as the above analogue, is that this method extends to the production of conversion pipes with a size of 290 × 12 mm with a ratio of D / S = 24.2 and does not solve technological issues of heating, flashing and rolling lash pipes measuring 287 × 11 × 25500-27000 mm with a ratio D / S = 26.1 from solid bars of steel grade 04X14T5R2F-Sh, continuous in height, with boron content from 2.0 to 3.0%.

The objective of the proposed method is the development of a technological process for the production of a new size of conversion pipe lashes of increased length from low plastic steel with boron content from 2.0 to 3.0% at TPU 8-16 ″ with pilgrim mills, reducing the weight of the hexagonal billet pipe by 17- 18%, and consequently, a decrease in their cost, a decrease in the mass of shelves while increasing their capacity, i.e. increasing the mass of spent nuclear fuel, increasing the reliability of racks for storing and transporting spent nuclear fuel at newly commissioned and reconstructed nuclear facilities.

The technical result is achieved by the fact that the method of production of hexagonal billets with turnkey size 255 ± 2.0 × 5.0 + 1.5 / -1.0 × 4300 + 80 / -30 mm for storage and transportation of spent nuclear fuel from low-ductility steel 04Kh14T5R2F-Sh with boron content from 2.0 to 3.0%, characterized in that the ingots are cast by electroslag remelting with a size of 480 × 1800 ± 25 mm, turning of their outer surface to remove casting defects into ingot ingots of size 465 ± 5.0 × 1800 ± 25 mm, drilling of a through central hole diameter m 100 ± 5 mm. heating ingot blanks to a temperature of 1040-1050 ° C, piercing ingot blanks in a cross-helical rolling mill into sleeves of size 460 × ext. 290 × 2820-2900 mm with a diameter reduction of Δ from 0 to 2.2% and a hood μ _pr from 1.59 to 1.66, the rolling of sleeves in pilger in steel making tube-lash size 287 × 11 mm × 25500-27000 stretch μ _f = 10.26 and swaging diameter Δ = 37,4%, cutting of pipe-lash a hot cutting saw into multiple pipes 10,200-10,500 mm long and the remainder, straightening them, cutting multiple length pipes into crack pipes, boring and turning into cylindrical pipes of size 281.1 ± 2.0 × 5 + 1.5 / -1, 0 and t Warm profiling into hexagonal workpieces of a given size.

Comparative analysis with the prototype shows that the inventive method differs from the known one in that electroslag remelting ingots are cast with a size of 480 × 1800 ± 25 mm, grind them on the outer surface to remove casting defects into ingots of 465 ± 5.0 × 1800 ± 25 mm, central through holes are drilled with a diameter of 100 ± 5 mm, ingot billets are heated to a temperature of 1040-1050 ° C, ingot billets are flashed in a cross-screw mill into sleeves measuring 460 × ext. 290 × 2820-2900 mm with compression diameter Δ from 0 to 2.2% and elongation with a stiff μ _pr from 1.59 to 1.66, the sleeves are rolled on a pilgrim mill in a whipping pipe with a size of 287 × 11 × 25500-27000 mm with a hood μ _p = 10.26 and a diameter reduction Δ = 37.4%, they cut the pipe-lashes with a hot-cutting saw into multiple pipes 10,200-10,500 mm long and the remainder, straighten them, cut pipes of multiple lengths into pipe-cuts, boring and turning into cylindrical pipes measuring 281.1 ± 2.0 × 5 + 1, 5 / -1.0 and warm profiling into hexagonal workpieces of a given size. 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 patentability "inventive step".

The invention can be illustrated by the following example. To implement the method according to the invention, 10 ingot billets (5 heats) of ESR of steel grade 04X14T5R2F-Sh of the supply of OAO ZMZ with a boron content of 2.52 to 2.85% were used. ESR ingots-blanks were divided into two parts with equal boron content. Five ingot blanks measuring 460-480 × 100 × 1650-1750 mm were manufactured and rolled according to existing technology. Five ESR ingots-blanks with a total mass of 11.666 tons were heated, stitched into sleeves of size 480 × ext. 295 × 2420-2490 mm on a mandrel with a diameter of 280 mm with a drawing coefficient Δ from 1.38 to 1.51, and then rolled on TPU 8 -16 ″ with pilgrim mills in conversion coars with a size of 287x11-24100-24900 mm with a drawing ratio of 11.81. Each lash pipe was marked into four crate tubes 6100-6250 mm long. In the process of preliminary acceptance, two pipe-cracks were rejected for flaws from the side of the seed ends - defects in the rental. In workshop No. 5 for machining - boring and turning and profiling, 18 krats were shipped, of which two more krats were rejected during the machining of the outer and inner captures. 16 hexagonal billets-pipes with a turnkey size of 255 × 5 × 4325 mm and a total weight of 2,368 tons were profiled and accepted as fit. The average expenditure coefficient of the metal for pipes of this batch was 4.927.

Five ESR ingots with boron content from 2.52 to 2.85%, with a total weight of 12.010 tons were cast, turned into ingot billets, heated and rolled into steel tubes 287 × 11 × 25700-26200 mm in size. Each whip tube was marked into five krat tubes 5100-5450 mm long. In the process of preliminary acceptance, two pipes were rejected for flaws on the side of the pilgrim head - rolled defects. In workshop No. 5, 23 krats were shipped for machining - boring and turning and profiling, of which two krats were rejected during the machining process - one for the outer captivity, and the second for the inner captivity. 21 hexagonal billet pipes with a total weight of 3.108 tons were profiled and accepted as fit. The average expenditure coefficient of metal for pipes of this batch was 3.864.

Data on the production of hexagonal pipe blanks with a turnkey size of 255 ± 2.0 × 5.0 + 1.5 / -1.0 × 4300 + 80 / -30 mm, according to the existing and proposed methods, for storage and transportation of waste nuclear fuel from conversion pipes 287 × 11 mm in size, rolled at GPU 8-16 ″ of ChGPZ OJSC with pilgrim mills from ingots-blanks of electroslag remelting of low-plastic article 04X14T5R2F-Sh with a boron content of 2.52-2.85%. cast at OJSC “ZMZ”. are given in table 1.

It can be seen from the table that rolling mill tubes of 287x11 mm in size according to the existing technology were produced from ingot blanks of 460-480 × 100 × 1650-1725 mm in size, which were heated to a temperature of 1040-1050 ° C, and were sewn into sleeves in a cross-helical rolling mill size 480 × ext. 295 × 2420-2490 mm on a mandrel of 280 mm with an extractor hood μ from 1.44 to 1.51, with a diameter rise of δ from 0 to 4.3%. Rolling conversion tubes with a size of 287 × 11 mm in the steady state process was carried out with an extractor μ = 11.81. As a result, from 5 redistribution lash pipes measuring 287 × 11 × 24100-24900 mm, longitudinal flaws 1.5–1.8 m long were found at 2 from the seed end, resulting in the loss of 2 kraths in length. In workshop No. 5, 18 krats were shipped. In the process of redistribution (boring and turning), 2 cracks were rejected for external captures and cracks, bringing the wall thickness beyond the negative tolerance field of 4.0 mm. The expenditure coefficient of the metal (the ratio of the mass of a given metal in production to the mass of delivered hexagonal tubes-blanks) for hexagonal tubes-blanks of this batch was 4.927. According to the proposed technology, 5 ingot blanks with a size of 460-470 × 100 × 1775-1825 mm were set into production, which were heated to a temperature of 1040-1050 ° C, stitched in a cross-helical rolling mill into sleeves measuring 460 × ext. 290 × 2900 mm on a mandrel with a diameter of 280 mm with a fit in diameter δ from 0 to 2.2%, with a hood μ from 1.59 to 1.66. Rolling of conversion pipes of 287 × 11 × 25700-26200 mm in size was performed in a caliber of 292 mm on mandrels with a diameter of 268/289 mm, heated to a temperature of 500-550 ° C, by rolling tuning carbon sleeves. As a result, from 5 redacting lash tubes measuring 287 × 11 × 25700-26200 mm, 25 krat tubes were obtained with a length of 5100-5450 mm, of which, at two edges, from the pilgrim heads were transverse flaws at a length of 0.8 and 1 , 9 m, which led to the loss - marriage of two krats in length. In shop No. 5, 23 krats were shipped. In the process of redistribution (boring and turning), 2 cracks were rejected: of them 1 time for external captures, and the second time for internal captures, displaying the wall thickness beyond the negative tolerance field of 4.0 mm. The expenditure coefficient of the metal for the hexagonal billet pipes of this batch was 3.864, i.e. for each ton of hexagonal billets, metal savings of 1063 kg were obtained.

Thus, according to the proposed method, in the production of a pilot batch of hexagonal pipe blanks with a turnkey size of 255 ± 2.0 × 5 + 1.5 / -1.0 × 4300 + 80 / -30 mm from 04X14T5R2F- mild steel Ш with boron content from 2.52 to 2.85%, a reduction in the expenditure coefficient of the metal was obtained during the redistribution of the ingot-billet - the conversion pipe-hexagonal pipe-billet by 1063 kg per ton of hexagonal pipe-billets.

Claims (1)

Method for the production of hexagonal tube blanks with a turnkey size of 255 ± 2.0 × 5.0 + 1.5 / -1.0 × 4300 + 80 / -30 mm for storage and transportation of spent nuclear fuel from 04X14T5R2F-Sh low-plastic steel with a boron content of 2.0 to 3.0%, characterized in that the ingots are cast by electroslag remelting with a size of 480 × 1800 ± 25 mm, turning of their outer surface to remove casting defects into ingots of 465 ± 5.0 × 1800 ± 25 mm, drilling a through center hole with a diameter of 100 ± 5 mm, heating ingots to temperaments Aturi 1040-1050 ° C, firmware ingots-mill blanks in a helical rolling sleeve in size × 460 × vn.290 2820-2900 mm with a reduction of the diameter Δ of from 0 to 2.2% stretch of 1.59 μ _ave to 1.66, the rolling of sleeves in pilger in steel making tube-lash size 287 × 11 mm × 25500-27000 stretch μ _f = 10.26 and swaging diameter Δ = 37,4%,, cutting of pipes hot saw-lashes cutting into multiple pipes with a length of 10,200-10,500 mm and the remainder, straightening them, cutting pipes of multiple lengths into pipe-cuts, boring and turning into cylindrical pipes of size 281.1 ± 2.0 × 5 + 1.5 / -1.0 and warm profiling in hex threaded billet pipes of a given size.