RU2557388C2 - PRODUCTION OF 252,6±1,8×5,0+1,5/-1,0×4300+80/-30 mm HEXAGONAL "TURNKEY" PIPE-BILLETS FOR COMPACTED STORAGE AND TRANSPORTATION OF USED NUCLEAR FUEL - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to hexagonal pipe rolling. This process comprises ESR casting of hollow ingots from low-ductility steel and turning them to ingots-billets. Said hollow ingots-billets are arranged in one row at furnace bars in lots of 10-12 pieces, heated to 1030-1040°C at the rate of 2.6-2.8°C/min with uniform canting. Said ingots-billets after feed from the furnace are rolled at Pilger furnace to rerolled pipe sets of specified sizes. Then said pipe sets are cut by hot-cutting saw to pipe lengths and straightened. Said pipe lengths are cut to two length billets in length not over 5000 mm, bored and turned to pipe billets and shaped to hexagonal preset-size pipes.

EFFECT: lower metal input, decreased weight and costs.

3 cl, 1 tbl

Description

The invention relates to methods for rolling pipes, in particular to a method for the production of hexagonal tube blanks with a turnkey size of 252.6 ± 1.8 × 5.0 + 1.5 / -1.0 × 4300 + 80 / -30 mm for storage and transportation of spent nuclear fuel from hollow ingot billets obtained by electroslag remelting from low-ductility steel 04X14T5R2F-Sh with boron content from 2.0 to 3.0%.

In pipe production, there is a known method for producing hexagonal tubes-blanks for storing and transporting spent nuclear fuel from hollow ingots-blanks obtained by electroslag remelting from low-plastic boron-containing steel, including the smelting of hollow ingots, their boring and turning to remove shells and traces of flux into hollow ingots billets, heating of hollow ingots-billets, their rolling in a pipe-rolling installation with pilgrim mills into conversion pipe-lashes, cutting with a hot cutting saw of technological processes odes-pilgrim heads and seed ends, cutting tubular tubes into multiple length tubes that are cut into Krath blanks, bored and turned into blank tubes that are profiled into hexagonal tube blanks with a turnkey size of 252.6 ± 1 , 8 × 5.0 + 1.5 / -1.0 × 4300 + 80 / -30 mm (RU No. 2317865, B21B 23/00, B21B 21/04, published 02.27.2008).

The disadvantage of this method is the increased relative value of the end waste (seed ends and pilgrim heads), as well as the impossibility of its use in the manufacture of redistribution pipes from steel 04X14T5R2F-Sh with a high boron content of 2.0-3.0 wt.%, Which have a lower plastic.

The closest in technical essence and the achieved technical result is a method for the production of hexagonal billets of size 257 + 2.0 / -3.0 × 6.0 + 2.0 / -1.0 × 4300 + 80 / -30 mm for storage and transportation of spent nuclear fuel, including casting by electroslag remelting of hollow ingots from low-ductility steel 04X14T5R2F-Sh with boron content from 2.0 to 3.0%, size 470 ± 5.0 × int. 275 ± 5.0 × 3000-3200 mm, boring and turning them into hollow ingots-blanks of size 460 ± 5.0 × ext. 285 ± 5.0 × 3000-3200 mm, heating to a temperature of 1040-1060 ° C, rolling into conversion tubes measure 290 × 12 × 25300-26700 mm with a hood µ from 9.45 to 9.70 and compression in diameter Δ from 35.6 to 37.0% and the saw removing hot cutting technological waste - pilgrim heads and seed ends, after which lash pipes are cut on a hot cutting saw into multiple pipes of length 10150 ± 50 mm and the remainder, straightening, cutting of multiple pipes into two billets of at least 5000 mm length, boring and turning into blanks of size 284.75 + 2.0 / -3.0 × 6 + 2.0 / -1.0 mm and profiling into hexagonal pipes of a given size. Rolling hollow ingots into blanks in 295 mm calipers on mandrels heated to a temperature of 500-550 ° C by rolling tuning carbon sleeves, while a carbon ring of 480 ± 5.0 × ext. 280 ± 5 is put on the mandrel , 0 × 250 ± 10 mm, a mandrel with a carbon ring is introduced into a hollow ingot-blank, rolls are bred, forming a caliber of 300 mm, the front end-seed is run in a length equal to 0.8-1.0 of the rollback path of the feeding apparatus, with an extractor hood µ from 7.8 to 8.1, the sleeve with the mandrel is returned to its original position, rolls are reduced, forming a caliber of 29 5 mm, and the front run-in end and the entire hollow ingot-billet are rolled into a whip transfer tube measuring 290 × 12 × 25300-26700 mm, and the steady-state rolling process of the conversion whip tubes is carried out at a rotational speed of the pilgrim mill rolls of 42-44 revolutions per minute at the same time, when seeding at a length equal to 1.2-1.5 of the rollback path of the feeding apparatus, the speed of rotation of the rolls is reduced by 15.0-16.0%, and when running the pilgrim head at a length equal to 1.0-1 , 2 ways to roll back the feeding apparatus, produce a decrease in the speed of rotation of the rolls by 10.0-11.0%.

One of the main disadvantages of this prototype, as well as the above analogues, is that with increased end waste (seed ends and pilgrim heads) from ingot blanks weighing up to 2250 kg instead of five krats with a size of 284 × 11 × 5000-5250 mm, we get only four, which leads to an increased consumption coefficient of boron-containing steel, and this method also applies to the production of conversion pipes of 290 × 12 mm in size, and does not solve the technological issues of the production of conversion pipes of 284 × 11 × 25600-26600 mm in size the D / S ratio of hollow ingot blanks with a boron content of 2.0 to 3.0%.

The objective of the proposed method is the development of the technological process for the production of pig tubes with a size of 284 × 11 mm from low-ductility steel with a boron content of 2.0 to 3.0% at TPU 8-16 "with pilgrim mills for their subsequent conversion into hexagonal tubes of size" turnkey "252.6 ± 1.8 × 5 + 1.5 / -1.0 × 4300 + 80 / -30 mm for storage and transportation of spent nuclear fuel, reducing the share of process waste (seed ends and pilgrim heads), the number defective flaws at the seed ends, reduction in expense ratios metal indentation during redistribution of a hollow ingot-billet ESR - conversion tube-billet - hexagonal tube-billet of a new size, Reducing the mass of hexagonal tubes-blanks, reducing the mass of shelving while increasing their capacity, lowering the cost of the final production of hexagonal pipes from steel 04X14T5R2F-Sh, which in turn will make it possible to produce hexagonal pipes of a new size with a high content of boron, and therefore, increase the reliability of racks for storing and transporting spent nuclear fuel.

The technical result is achieved by the fact that in the known method for the production of hexagonal tube blanks with a turnkey size of 252.6 ± 1.8 × 5.0 + 1.5 / -1.0 × 4300 + 80 / -30 mm for storage and transportation of spent nuclear fuel, including casting by electroslag remelting of hollow ingots of low-plastic steel grade 04X14T5R2F-Sh with boron content from 2.0 to 3.0%, size 470 ± 5.0 × int. 270 ± 5.0 × 3000 ± 100 mm, boring and turning them into hollow ingots-blanks of size 450 ± 5.0 × ext. 280 ± 5.0 × 3000 ± 100 mm, heating to a temperature of 1030-1040 ° C, rolling into conversion pipe-lashes with a size of 284 × 11 × 25600 -26600 mm with an extractor hood μ from 9.88 to 10.39, diameter reduction Δ from 36.18 to 37.58% and hot saw removal of technological waste - pilgrim heads and seed ends, after which the whip pipes are cut by multiple hot saws pipes with a length of 10,100 ± 50 mm and the remainder correct, multiple pipes are cut into two billets-crates with a length of at least 5,000 mm, bored and turned into billet pipes measuring 278.5 ± 1.8 × 5.0 + 1.5 / - 1.0 mm and profiled into hexagonal pipes of a given size, hollow ingots-blanks are planted in one row on the furnace grates in batches of 10-12 pieces at a pace ature in the third zone is 800-900 ° C and can withstand without canting for 40-60 minutes, heated to a temperature of 1030-1040 ° C at a speed of 2.6-2.8 ° C per minute with a uniform canting from 22nd to 7th window after 12-15 minutes at an angle of ≈300-310 °, maintained for 40-50 minutes with uniform tilting from the 7th to the 4th window after 13-17 minutes, turn from the 4th window to the furnace pit and dispensed from the furnace with a center temperature of hollow ingots-blanks at a temperature of 1030-1040 ° C, the next two hollow ingots-blanks are planted after turning over the first 2 hollow ingots-blanks from hollow grates, hollow ingots-blanks they melt into whipping pipe-pipes with a size of 284 × 11 × 25600-26600 mm in caliber 290 mm on mandrels with a diameter of 263/264 mm.

Comparative analysis with the prototype shows that the inventive method for the production of hexagonal tube blanks with a turnkey size of 252.6 ± 1.8 × 5.0 + 1.5 / -1.0 × 4300 + 80 / -30 mm for storage and Transportation of spent nuclear fuel is distinguished by the fact that hollow ingots from low plastic steel 04X14T5R2F-Sh are cast by electroslag remelting with boron content from 2.0 to 3.0% with a size of 470 ± 5.0 × ext. 270 ± 5.0 × 3000 ± 100 mm, boring and turning them into hollow ingots-blanks of size 450 ± 5.0 × ext. 280 ± 5.0 × 3000 ± 100 mm, heating to a temperature of 1030-1040 ° C, rolling into conversion tubes with a size of 284 × 11 × 25600-26600 mm with a hood µ from 9.88 to 10.39 and compression in diameter Δ from 36.18 to 37.58% and hot saw cutting of technological waste - pilgrim heads and seed ends, then lash pipes are cut with a hot cutting saw into multiple pipes with a length of 10,100 ± 50 mm and the remainder is corrected, multiple pipes are cut into two billets of at least 5,000 mm in length, bored and turned into billet pipes measuring 278.5 ± 1.8 × 5.0 + 1.5 / -1.0 mm and shaped into hexagonal pipes of a given size, hollow ingots-blanks are planted in one row on the grates of the furnace party and 10-12 pieces at a temperature in the third zone of 800-900 ° C and kept without tilting for 40-60 minutes, heated to a temperature of 1030-1040 ° C at a speed of 2.6-2.8 ° C per minute with a uniform the tilting from the 22nd to the 7th window after 12-15 minutes at an angle of ≈300-310 °, kept for 40-50 minutes with a uniform tilting from the 7th to the 4th window after 13-17 minutes, turn over The fourth window into the pit of the furnace and is dispensed from the furnace with a center temperature of hollow ingot-blanks of 1030-1040 ° C, the next two hollow ingot-blanks are planted after turning over the grates of the first 2 hollow ingot-blanks, hollow with molds-blanks are rolled into a whipping pipe-pipe measuring 284 × 11 × 25600-26600 mm in caliber 290 mm on mandrels with a diameter of 263/264 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 this technical field, did not reveal the signs that distinguish the claimed method from the prototype, which corresponds to the patentability of "inventive step".

The implementation of the method according to the invention is presented by the following example (t.1).

10 hollow ingots-billets (5 heats) of EShPs of steel grade 04X14T5R2F-Sh delivered by OAO "ZMZ" with a boron content of 2.37 to 2.94 were set into production. ESW hollow ingots-blanks were divided into two parts with equal boron content. Five ingot blanks measuring 475-480 × ext. 280 × 2300-2400 mm were manufactured and rolled according to existing technology. Five hollow ESR ingots-blanks with a total mass of 10.336 tons were heated to a temperature of 1050-1060 ° C and rolled on 8-16 "TPU with pilgrim mills into conversion pipes 284 × 11-23700-24600 mm in size with a drawing coefficient µ from 12.01 up to 12.40. Each lash pipe was marked into four crater pipes with a length of 5900-6150 mm. During the preliminary acceptance, three crater pipes were rejected for flaws - rolled defects: two cracks from the seed ends, and the third one from the pilgrim side In workshop No. 5 for machining, boring, turning and profiling 17 krats have been made, of which two more krats were rejected during the machining process: one on the outer layer and transverse cracks, and the second on the inner layer. 15 hexagonal billet pipes with a total mass of 2.175 tons were profiled and accepted fit. billet pipes of this batch amounted to 4.752.

Five hollow ESR ingots with a boron content of 2.37 to 2.94, with a total weight of 10.785 tons, were cast, turned and bored into hollow ingots-blanks, heated and rolled into pig tubes measuring 284 × 11 × 25300-26500 mm in accordance with claims 1-4 of the claims. Each lash pipe was marked into five krat pipes 5000-5300 mm long. In the process of preliminary acceptance, two pipes were rejected for flaws from the pilgrim heads - rolled defects. In shop No. 5, 23 krats were shipped for machining, turning, boring 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 pipe-workpieces with turnkey size 252.6 ± 1.8 × 5.0 + 1.5 / -1.0 × 4300 + 80 / -30 mm, with a total weight of 3.045 tons were profiled and accepted as fit. The average consumption coefficient of metal for pipes of this batch amounted to 3,542.

Data on rolling and delivery of conversion pipes 284 × 11 mm in size from hollow ingots-billets of steel grade 04X14T5R2F-Sh with boron contents from 2.37 to 2.94% cast at ZMZ OJSC and rolled at 8-16 "TPU with according to the existing and proposed methods, the production of hexagonal tube blanks of turnkey size 252.6 ± 1.8 × 5.0 + 1.5 / -1.0 × 4300 + 80 / - by the pilgrim mills of JSC "ChTTTZ" 30 mm are given in the table.

Thus, the method according to the invention ensures the achievement of the technical result: reducing the expenditure coefficient of the metal, reducing the weight of the hexagonal tubes-blanks, and therefore, reducing the weight of the racks with an increase in their capacity, reducing the cost of the commodity hexagonal tubes-blanks and increasing the reliability of the racks for storage and transportation spent nuclear fuel.

Data on rolling and delivery of conversion pipes 284 × 11 mm in size from hollow ingots-billets of steel grade 04X14T5R2F-Sh with a boron content of 2.37-2.94%, cast at OAO ZMZ and rolled at TPU 8-16 at OAO ChelPipe "according to the existing and proposed methods, the production of turn-key" hexagonal tubes-blanks from them 252.6 ± 1.8 × 5.0 + 1.5 / -1.0 × 4300 + 80 / -30 mm.

Claims (3)

1. Method for the production of hexagonal billet pipes measuring 252.6 ± 1.8 × 5.0 + 1.5 / -1.0 × 4300 + 80 / -30 mm for storage and transportation of spent nuclear fuel, including casting by electroslag hollow remelting ingots from low-ductility steel 04X14T5R2F-Sh with boron content from 2.0 to 3.0% of size 470 ± 5.0 × ext. 270 ± 5.0 × 3000 ± 100 mm, boring and turning them into hollow ingots-blanks of size 450 ± 5.0 × ext. 280 ± 5.0 × 3000 ± 100 mm, which are placed in one row on the furnace grates in batches of 10-12 pieces at a temperature in the third zone of the furnace of 800-900 ° C and can withstand without tilting for 40 -60 minutes, naked they are chewed up to a temperature of 1030-1040 ° C at a speed of 2.6-2.8 ° C per minute with a uniform tilting from the 22nd to the 7th window after 12-15 minutes at an angle of 300-310 °, kept for 40- 50 minutes with a uniform pitching from the 7th to the 4th window in 13-17 minutes, turn over from the 4th window to the furnace pit, and after being dispensed from the furnace, they are rolled on a pilgrim mill in a conversion pipe-lash of 284 × 11 × 25600 -26,600 mm with a hood of 9.88 - 10.39, compression in diameter of 36.18 - 37.58% and removal of the pilgrim heads and seed ends by hot-sawing of the technological waste, after which the lash tubes cut the saw hot cutting into multiple pipes with a length of 10,100 ± 50 mm and the remainder correct, multiple pipes are cut into two workpieces-krat not less than 5,000 mm long, bored and turned into pipes - workpieces with a size of 278.5 ± 1.8 × 5.0 + 1.5 / -1.0 mm and shaped into hexagonal pipes of a given size. 2. The method according to claim 1, characterized in that after tilting from the grates of the first 2 hollow ingot blanks, the following two hollow ingot blanks are planted.  3. The method according to claim 1, characterized in that the hollow ingots-billets are rolled into a whipping pipe in a caliber of 290 mm on mandrels with a diameter of 263/264 mm.