RU2470724C1 - METHOD OF MAKING HEXAGONAL TUBE BILLETS SIZED TO 257+2,0/-3,0×6,0+2,0/-1,0×4300+80/-30 mm INTENDED FOR STORAGE AND TRANSPORTATION OF SPENT NUCLEAR FUEL - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: proposed method comprises making hollow ingots by electroslag remelting from low-ductile steel "04Х14Т5P2Ф-Ш" with boron content of 2.0 to 3.0%, boring and turning said ingots to hollow ingots and be heated and rolled to tube stock and cutting off process wastes, i.e. Pilger heads and seed ends. Thereafter, tube stock is hot-sawn into multiple tubes and ends, and straightened. Multiple tubes are cut into two billets to be bored and turned into tube billets to be shaped to preset size hexagonal tubes. Note here that billet sizes and machining conditions are specified for all machining stages.

EFFECT: decreased wastes rules out cracks and flaws.

3 cl, 1 tbl

Description

The invention relates to methods for rolling pipes, in particular to a method for the production of hexagonal tubes-blanks of size 257 + 2.0 / -3.0 × 6 + 2.0 / -1.0 × 4300 + 80 / -30 mm for storage and transportation spent nuclear fuel from hollow ingot billets obtained by electroslag remelting from low-plastic steel 04X14T5R2F-Sh with boron content from 2.0 to 3.0%.

The closest in technical essence and the achieved technical result is a method for producing hexagonal tubes-blanks for storage and transportation of spent nuclear fuel from hollow ingots-blanks obtained by electroslag remelting from low-plastic boron-containing steel, including the melting of hollow ingots, their boring and turning before removing shells and traces of flux into hollow ingots-billets, heating of hollow ingots-billets, their rolling in a pipe-rolling installation with pilgrim mills in conversion plants loss, cutting with a hot cutting saw of technological waste - pilgrim heads and seed ends, cutting lashes into multiple pipes, which are cut into Krath blanks, bored and turned into billet pipes that are profiled into hexagonal tubes of 257 + 2.0 / -3.0 × 6 + 2.0 / -1.0 × 4300 + 80 / -30 mm (RU 2317865, B21B 23/00, B21B 21/04, publ. 02.27.2008).

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

The objective and technical result of the invention is to reduce the number of flaws in flaws at the seed ends and to reduce the expenditure coefficient of the metal in the manufacture of hexagonal pipes from steel 04X14T5R2F-Sh.

The technical result is achieved in that a method for the production of hexagonal billets of size 257 + 2.0 / -3.0 × 6 + 2.0 / -1.0 × 4300 + 80 / -30 mm for storage and transportation of spent nuclear fuel, from hollow ingots-billets obtained by electroslag remelting from low-plastic steel grade 04X14T5R2F-Sh with boron content from 2.0 to 3.0% with rolling from them at a pipe-rolling machine with pig mill mill tubes 290 × 12 mm in size includes casting of hollow ingots by electroslag remelted, bored and turned to remove shells and traces flux into hollow ingots-billets, heating hollow ingots-billets, their rolling on a pipe-rolling plant with pilgrim mills into conversion lashes, a piece of hot-sawing of technological waste - pilgrim heads and seed ends, cutting of lashes into multiple tubes that cut on krat blanks, bore and grind them into blank tubes and profiled into hexagonal tubes measuring 257 + 2.0 / -3.0 × 6 + 2.0 / -1.0 × 4300 + 80 / -30 mm, electroslag remelting ingots are cast with a hollow size of 470 ± 5 × ext. 275 ± 5 × 3000-3200 mm, bored t and machined into hollow ingots-billets with a size of 460 ± 5 × ext. 285 ± 5 × 3000-3200 mm, heated to a temperature of 1040-1060 ° C and rolled into a whipping pipe with a size of 290 × 12 × 25300-26700 mm with a hood µ from 9.45 to 9.7 and compression in diameter Δ from 35.6 to 37.0%, whip pipes are cut on a hot cutting saw into multiple pipes 10150 ± 50 mm long and the remainder is correct, multiple pipes are cut into two Krat blanks with a length of at least 5000 mm, are bored and turned into blanks of size 284.75 + 2.0 / = 3.0 × 6 + 2.0 / -1.0 mm and profiled into hexagonal tubes - blanks of a given size .

The technical result is also achieved by the fact that hollow ingots-billets are rolled into whipping tubes in a caliber of 295 mm on mandrels heated to a temperature of 500-550 ° C by rolling adjusting carbon sleeves, according to the technology: a carbon ring of size 480 ± 5 is put on the mandrel × ext. 280 ± 5.0 × 250 ± 10 mm, a mandrel with a carbon ring is inserted 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 ways to roll back the feeding apparatus with an extractor µ from 7.8 to 8.1, the sleeve with the mandrel is returned to and a similar position, rolls are reduced, forming a caliber equal to 295 mm, and the front run-in end and the hollow ingot-billet are rolled into a transfer pipe-lash measuring 290 × 12 × 25300-26700 mm; and the steady-state rolling process of conversion tubes is carried out at a rotational speed of the rolls of the pilgrim mill 42-44 revolutions per minute, when seeding, at a length equal to 1.2-1.5 of the rollback path of the feeding apparatus, the rolls are rotated at a speed of 15.0- 16.0%, and during the rolling-rolling of the pilgrim head at a length equal to 1.0-1.2 of the rollback path of the feeding apparatus, the rotation speed of the rolls is reduced by 10.0-11.0%.

The implementation of the method according to the invention is presented by the following example.

10 hollow ingots (5 heats) obtained by electroslag remelting of steel grade 04X14T5R2F-Sh with boron content from 2.57 to 2.78 were assigned to production. Hollow ingots were divided into two parts with equal boron content. Five ingot blanks with a size of 475-480 × ext. 280 × 2300-2400 mm were manufactured and rolled by known technology. Five hollow ingots - ESR blanks with a total mass of 10.731 tons were heated to a temperature of 1050-1070 ° C and rolled at 8-16 "TPU with pilgrim mills into conversion pipes - whips 290 × 12-21900-22700 mm in size with a drawing coefficient µ from 10 81 to 11.16. Each lash pipe was marked into four blanks-crats 5400-5700 mm long.In the process of preliminary acceptance, four blanks-craters were rejected for flaws - rolled defects; two blanks-crats - from the seed ends, one blank-krat in the middle, and the fourth blank-krat - on the pilgrim's side 16 krat blanks were shipped for machining, turning, boring and profiling, of which two more blank pipes were rejected during machining: one on the outer sheath and transverse cracks, and the second on the inner sheath. 14 hexagonal tubes-blanks with a size of 257 + 2.0 / -3.0 × 6 + 2.0 / -1.0 × 4300 + 80 / -30 mm with a total weight of 2.590 tons were accepted with a total weight of 2.590 tons. The average expenditure coefficient of the metal for the pipes of this batch was 4.143 .

Five hollow ESR ingots from low-plastic steel grade 04X14T5R2F-Sh with a boron content of 2.57 to 2.78, a total weight of 11.749 t and a size of 470 ± 5 × in. 275 ± 5 × 3000-3200 mm were cast by electroslag remelting, turned and bored into hollow ingots-billets of size 460 ± 5 × ext. 285 ± 5 × 3000-3200 mm, heated and rolled into porous whip tubes of size 290 × 12 × 25300-26300 mm in accordance with the method of the invention. In this case, the ingots were turned and bored to remove shells and traces of flux and surface cleanliness R _z = 35 ± 3 μm and the dimensions of the hollow ingot-billet were 460 ± 2 × 285 ± 3 × 3000-3200 mm. After that, the hollow ingots were heated to a temperature of 1040-1060 ° C and rolled into conversion pipes of 290 × 12 × 25300-26300 mm in size on an 8-16 "TPU tube mill with pilgrim mills on a heated mandrel with a carbon ring. Rolling hollow ingots-blanks in the pipe-lash on the mandrel were driven with a hood µ from 9.45 to 9.7 and compression in diameter Δ from 35.6 to 37.0%. Then, the lash pipes were cut on a hot cutting saw into multiple pipes with a length of 10150 ± 50 mm and the remainder ruled, cut multiple pipes into two blanks-krata with a length of at least 5000 mm, bored and to grind the tube billet size 284,75 + 2,0 / = 3,0 × 6 + 2.0 / -1.0 mm, and a hexagonal profiled-tube blank of a predetermined size.

When carrying out the method according to the invention, hollow ingots were rolled into whipping tubes in a caliber of 295 mm on mandrels heated to a temperature of 500-550 ° C by rolling adjusting carbon sleeves as follows: a carbon ring of 480 ± 5 × vn was put on the mandrel .280 ± 5.0 × 250 ± 10 mm, a mandrel with a carbon ring was inserted into a hollow ingot-blank, rolls were bred, forming a caliber of 300 mm, the front end-seed was run in a length equal to 0.8-1.0 rollback paths a feeding apparatus with an extractor µ from 7.8 to 8.1. Then the sleeve with the mandrel was returned to its original position, the rolls were brought together, forming a caliber of 295 mm, and the front rolled end and the hollow ingot-billet were rolled into a transfer pipe-weave measuring 290 × 12 × 25300-26700 mm.

In addition, the steady-state rolling process of the chimney tubes was carried out at a rotational speed of the pilgrim mill rolls of 42-44 revolutions per minute, while seeding, at a length equal to 1.2-1.5 of the rollback path of the feeding apparatus, the roll rotation speed was reduced by 15 , 0-16.0%, and when running-rolling the pilgrim head at a length equal to 1.0-1.2 of the rollback path of the feeding apparatus, the rotation speed of the rolls was reduced by 10.0-11.0%.

In the process of preliminary acceptance, two pipes were rejected for flaws from the pilgrim heads - rolled defects. In the process of manufacturing hexagonal pipes under the “key” 257 + 2.0 / -3.0, latent defects appeared and two more cracks were rejected: one on the outer captivity and one on the inner captivity. Twenty-one hexagonal pipes were profiled and accepted as turnkey billets of 257 + 2.0 / -3.0 × 6.0 + 2.0 / -1.0 × 4300 + 80 / -30 mm, with a total weight of 3.885 t The average consumption coefficient of metal for pipes of this batch was 3.024.

Data on rolling and delivery of conversion pipes 290 × 12 mm in size from hollow ingots-blanks of steel grade 04X14T5R2F-Sh with boron content from 2.57 to 2.78% obtained by the known method and the method according to the invention, production of hexagonal tubes-blanks from them turnkey size 257 + 2.0 / -3.0 × 6.0 + 2.0 / -1.0 × 4300 + 80 / -30 mm are given in the table.

Thus, the method according to the invention ensures the achievement of the technical result: reducing the number of defects on flaws at the seed ends and reducing the expenditure coefficient of the metal.

Claims (3)

1. Method for the production of hexagonal billets of size 257 + 2.0 / -3.0 × 6.0 + 2.0 / -1.0 × 4300 + 807-30 mm for storage and transportation of spent nuclear fuel, including electroslag casting remelting hollow ingots from low-ductility steel 04X14T5R2F-Sh with boron content from 2.0 to 3.0% with a size of 470 ± 5 × ext. 275 ± 5 × 3000-3200 mm, boring and turning them into hollow ingots-blanks with a size of 460 ± 5 × ext. 285 ± 5 × 3000-3200 mm, heating to a temperature of 1040-1060 ° C, rolling into a whip pipe of 290 × 12 × 25300-26700 mm in size with a hood µ from 9.45 to 9.70 and compression diameter Δ from 35.6 to 37.0% and saw removal th hot cutting of technological waste - pilgrim heads and seed ends, after which the whip pipes are cut on a hot cutting saw into multiple pipes with a length of 10150 ± 50 mm and the remainder is corrected, multiple pipes are cut into two billets of at least 5000 mm in length, bored and grind it into billet pipes measuring 284.75 + 2.07-3.0 × 6.0 + 2.0 / -1.0 mm and shape into hexagonal pipes of a given size. 2. The method according to claim 1, characterized in that the hollow ingots-billets are rolled into a whip pipe in a caliber of 295 mm on mandrels heated to a temperature of 500-550 ° C by rolling adjusting carbon sleeves, and a carbon ring is put on the mandrel size 480 ± 5 × ext. 280 ± 5.0 × 250 ± 10 mm, a mandrel with a carbon ring is inserted into a hollow ingot-blank, rolls are bred, forming a caliber of 300 mm, the front end is rolled in - seed at a length of 0, 8-1.0 ways to roll back the feeding apparatus with an extractor µ from 7.8 to 8.1, the sleeve with the mandrel is returned to its original position, the rolls are brought together, forming a caliber equal to 295 mm, and the front run-in end and the entire hollow ingot-billet are rolled into a transfer pipe-lash with a size of 290 × 12 × 25300-26700 mm. 3. The method according to claim 1, characterized in that the steady-state rolling process of the conversion pipe-lashes is carried out at a rotational speed of the rolls of the pilgrim mill 42-44 revolutions per minute, with the seed at a length equal to 1.2-1.5 rollback paths the feeding apparatus, reduce the speed of rotation of the rolls by 15.0-16.0%, and when running-rolling the pilgrim head at a length equal to 1.0-1.2 of the rollback path of the feeding apparatus, reduce the speed of rotation of the rolls by 10.0 -11.0%.