RU2470726C1 - METHOD OF MAKING 257+2,0/-3,0×6,0+2,0/-1,0×4300+80/-30 mm-HEXAGONAL TUBE BILLETS FOR PACKED STORAGE AND TRANSPORTATION OF USED NUCLEAR FUEL - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: proposed method comprises electroslag remelting of 470±5 "хвн." 270±5×3050±50 mm ingots from 04X14T5P2"Ф-Ш"-grade low-ductile steels with boron content of 2.0 to 3.0% with bottom and shrinkage parts and specified height to make Pilger heads in tube stock rolling and seed ends from ductile carbon steels, turning and boring to make hollow ingots to be rolled to tube stock. It comprises also removing machining wastes, that is, Pilger heads and seed ends to make tube sections of ductile carbon steels. Then, tube sections are cut to tube stock to be bored and turned to tube billets. Holes are bored for pull chain for hot shaping at ductile carbon steel parts. Note here that billet sizes and machining conditions are specified fat all machining steps.

EFFECT: reduced wastes and rejects.

1 tbl

Description

The invention relates to pipe and metallurgical industries, in particular to a method for the production of hexagonal pipe blanks with a turnkey size of 257 + 2.0 / -3.0 × 6 + 2.0 / -1.0 × 4300 + 80 / -30 mm for compacted storage and transportation of spent nuclear fuel from low plastic steel with a boron content of from 2.0 to 3.0%.

The closest in technical essence and the achieved result is a method for producing hexagonal tubes-blanks for compacted storage and transportation of spent nuclear fuel from hollow ingots-blanks obtained by electroslag remelting from low-plastic boron-containing steel, the bottom and shrinkage parts of hollow ingots of electroslag remelting forming at rolling the pig tubes the pilgrim head and the seed end are cast from plastic carbon steel grades, hollow ingots are bored they are hollowed and turned from the shrinkable side into hollow billets to the fusion boundaries of two metals in the bottom part of the ingots or with a shift towards plastic carbon steel, composite hollow ingots-billets are heated to a plasticity temperature of 1040-1060 ° C, after removal of technological waste - pilgrim heads and the seed ends made of plastic carbon steel grades on the side of the pilgrim heads and the seed ends leave sections of pipes made of plastic carbon steel grades 500-700 mm long after cutting the lashes into two pipes would be equal to length or multiple to the length of the billet for subsequent warm straightening of the pipe, the six-roll straightening machine would be set with plastic carbon steel ends, drilling holes for the pulling chain for warm profiling on pipe-workpieces with carbon plastic ends would be made in sections of pipe-workpieces made of plastic carbon steel grades, and the ends of the workpieces from plastic carbon steel grades are removed before heat treatment with all subsequent technological operations in the process.

(RU 2317865, B21B 21/04, published 02/27/2008).

One of the main disadvantages of this method is that increased end waste (seed ends and pilgrim heads) lead to an increased consumption coefficient of expensive boron-containing steel. In addition, the known method cannot be used for the manufacture of hexagonal tubes-blanks from steel 04X14T5R2F-Sh with a boron content of from 2.0 to 3.0%.

The objective and technical result of the invention is a method for manufacturing hexagonal tube blanks with a turnkey size of 257 + 2.0 / -3.0 × 6 + 2.0 / -1.0 × 4300 + 80 / -30 mm for compacted storage and transportation of spent nuclear fuel from low-ductility steel with boron content from 2.0 to 3.0%, which ensures a reduction in the share of technological waste (seed ends, pilgrim heads and defective sections of lash tubes), elimination of defects in flaws on seed ends and pilgrim heads .

The technical result is achieved in that 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 compacted storage and transportation of waste 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%, rolling from them at pipe rolling plants with pilgrim mills of conversion tubes of 290 × 12 mm in size, machining - turning and boring them into pipes of size 284.75 × 6.0 + 2.0 / -1.0 mm and warm profiles into hexagonal tubes-blanks are cast by hollow ingots with bottom and shrinkage parts, which form pilgrim heads and seed ends when rolling pig tubes, from plastic carbon steel grades, by boring and turning hollow ingots into hollow ingots, by heating and rolling into conversion pipes in the form of lashes, removal of technological waste - pilgrim heads and seed ends, leaving sections of pipes made of plastic carbon steel grades 500-700 mm long, cutting pipe lashes, warm dressing per pipe tubes in a six-roll straightening machine, with the task of making ends of plastic carbon steel grades, drilling holes for the pulling chain for warm profiling in sections of pipe blanks of plastic carbon steel grades and removing the ends of the pipe blanks of steel of carbon plastic grades before heat treatment, at In this case, electroslag remelting ingots are cast with a hollow size of 470 ± 5 × ext. 270 ± 5 × 3050 ± 50 mm, the bottom and shrinkage parts of which, made of plastic carbon steel grades, have a height corresponding to Obviously, from 0.04 to 0.05 and from 0.09 to 0.10 of the total height of hollow ingots, they grind and bore from the bottom side into hollow ingots-blanks of size 455 ± 5.0 × ext. 280 ± 5.0 × 3050 ± 50 mm, heated to a temperature of 1030-1050 ° C and rolled into a whip pipe of 290 × 12 × 26000-27000 mm in size on mandrels with a diameter of 264/265 mm with an extract of µ from 9.32 to 10.0 and compression Δ from 35.1 to 36.5% in diameter, after the technological waste has been removed, the whip pipes are cut with a hot cutting saw into pigs with a length of 10,800 ± 200, 10,200 ± 100 and the remainder, the first and third pigs are set for warm dressing with the ends of plastic carbon steel grades, the first transfer pipe is cut from the side of carbon steel into slab-blanks with a length of 5500 ± 200 mm and the remainder, the second is cut into two slab-blanks of equal length, bored and turned into blanks of size 284.75 × 6.0 + 2.0 / -1.0 mm and profiled into hexagonal billet tubes.

The method can be illustrated by the following example of implementation, which was implemented on the installation of the ЭШП of OJSC "ZMZ" and on the tube-rolling installation 8-16 "with pilgrim mills of OJSC" ChTPZ ".

10 hollow ingots-blanks (5 heats) of ESHP steel of grade 04X14T5R2F-Sh with a boron content of 2.64 to 2.85, the bottom and shrinkage parts of which are made of plastic carbon steel grades (steel 10), were assigned to production. ESW hollow ingots-blanks were divided into two parts with equal boron content.

Five ingot blanks with a size of 470 × ext. 280 × 2400-2500 mm were manufactured and rolled by known technology. The height (length L _d ) of the fused carbon metal to the bottom of the ingot blanks was from 300 to 350 mm, the height (length L _y ) of the fused carbon metal to the shrink part was from 120 to 150 mm. Five hollow EAW ingot billets with a total mass of 8.768 tons of 04X14T5R2F-Sh steel metal were heated to a temperature of 1050-1060 ° C and rolled at 8-16 "TPU with pilgrim mills into porous tubes measuring 290 × 12-22100-22600 mm with a drawing coefficient µ = 10.47 and a compression of 38.1% in diameter. Each lash pipe was marked into four krat pipes 5200-6000 mm long. The carbon ends from 600 to 700 mm long were left from the side of the seed ends and pilgrim heads depending on the total length of the conversion pipe-crates. Three tons during preliminary acceptance losses were rejected due to flaws - rolled defects: one time on the side of the seed end, second time on the side of the pilgrim head, and the third in the middle of the bottom pipe with boron content of 2.85%. For machining, turning, boring and warm profiling 17 krats were dispatched, of which three more krats were rejected during the machining process - one for the outer captivity, and two for the inner captivity and small flaws. Fourteen hexagonal pipe blanks with a turnkey size of 257 + 2.0 / -3.0 × 6.0 + 2.0 / -1.0 × 4300 + 80 / -30 mm with a total weight of 2,590 tons were profiled and accepted as suitable. The average expenditure coefficient of metal for steel 04X14T5R2F-Sh for hexagonal tubes of this batch was 3.385.

Five hollow ESR ingots with boron content from 2.64 to 2.85, total weight of steel 04Kh14T5R2F-Sh - 10.117 tons, were cast, turned and bored into hollow ingots-blanks, heated and rolled at pipe rolling plants with pilgrim mills into conversion pipes size 290 × 12 × 25900-26900 mm in accordance with the method according to the invention. The obtained conversion pipes were machined - machined and bored into pipes measuring 284.75 × 6.0 + 2.0 / -1.0 mm, followed by warm profiling into hexagonal tubes-blanks. At the same time, hollow ingots were cast with bottom and shrinkage parts, forming piligrim heads and seed ends during rolling of pipe tubes, from plastic carbon steel grades, boring and turning of hollow ingots into hollow ingots-blanks, their heating and rolling into tail tubes in the form of lashes . Technological waste was removed - pilgrim heads and seed ends, leaving sections of pipes made of plastic carbon steel grades 500-700 mm long. We conducted cutting of lash pipes, warm dressing of conversion tubes in a six-roll straightening machine, with the task of making ends of plastic carbon steel grades, drilling holes for the pulling chain for warm profiling in sections of pipe blanks of plastic carbon steel grades, and removing the ends of the steel workpieces plastic carbon grades before heat treatment. In this case, electroslag remelting ingots were cast hollow with a size of 470 ± 5 × ext. 270 ± 5 × 3050 ± 50 mm, the bottom and shrinkage parts of which, made of plastic carbon steel grades, had a height, respectively, from 0.04 to 0.05 and from 0.09 to 0.10 of the total height of the hollow ingots, turned and bored from the bottom into hollow ingots-blanks of size 455 ± 5.0 × ext. 280 ± 5.0 × 3050 ± 50 mm, heated to a temperature of 1030- 1050 ° C and rolled into a whip pipe of 290 × 12 × 26000-27000 mm in size on mandrels with a diameter of 264/265 mm with an extract of µ from 9.32 to 10.0 and a compression in diameter Δ from 35.1 to 36.5 %, but After removal of the technological waste, the whip pipes were cut with a hot cutting saw into cutting tubes with a length of 10,800 ± 200, 10,200 ± 100 and the remainder, the first and third dressing pipes were set for warm dressing with plastic carbon steel ends, the first dressing pipe was cut from the carbon steel side into krat-billets with a length of 5500 ± 200 mm and the remainder, the second was cut into two krat-billets of equal length, bored and turned into billet pipes measuring 284.75 × 6.0 + 2.0 / -1.0 mm and profiled into hexagonal commodity pipe blanks.

At the same time, each lash pipe was marked out into five pipe-crats 5100-5800 mm long. From the seed ends and the pilgrim heads, carbon ends from 600 to 800 mm long were left, depending on the total length of the conversion pipes. In the process of preliminary acceptance, one pipe-krat was rejected according to flaws in the middle part of the pipe-krat - a defect in rolling. Twenty-four krats were shipped for machining - turning, boring, and warm profiling, of which three krats were rejected during the machining - two on the outer captivity, and one on the inner captivity. 21 hexagonal pipe billets with a turnkey size of 257 + 2.0 / -3.0 × 6.0 + 2.0 / -1.0 × 4300 + 80 / -30 mm, with a total weight of 3.885 tons, were profiled and accepted as fit. The average expenditure coefficient of metal for steel 04X14T5R2F-Sh on the hexagonal tubes of this batch was 2.604.

Data on rolling and delivery of conversion pipes 290 × 12 mm in size from hollow ingots-billets of steel grade 04X14T5R2F-Sh with a boron content of 2.54-2.85%, the bottom and shrinkage parts of which are made (cast) of grade 10 steel, and rolled on TPU 8-16 "with pilgrim mills of ChTPZ OJSC and production of turnkey hexagonal tubes-blanks from them of 257 + 2.0 / -3.0 × 6.0 + 2.0 / -1.0 × 4300 + 80 / -30 mm are given in the table.

It can be seen from the table that the conversion of 290 × 12 mm pig tubes by the existing technology was carried out from hollow ingots-blanks with a size of 470 × ext. 280 × 2400-2500 mm, cast with soft iron (10 steel) to the bottom ends from 300 to 350 mm, and for shrinkage - from 120 to 150 mm, which were heated to a temperature of 1050-1060 ° C. Rolling of conversion tubes with a size of 290 × 12 mm was carried out with an extract of μ = 10.47 and compression in diameter of 37.9%. Technological waste was removed - pilgrim heads and seed ends were made, leaving sections of pipes made of plastic carbon steel grades 600-700 mm long, they cut lashing pipes into two pipes of equal length or multiple to the length of the billet, warm dressing of the conversion pipes in the six-roll straightening machine ends from plastic carbon steel grades, drilling holes for the pulling chain for warm profiling in sections of pipe-blanks from plastic carbon steel grades, and the removal of the ends of the pipes is finished tuples from ductile carbon steel grades produced before the heat treatment with the performance of all subsequent operations of the process. As a result, out of 5 conversion lash pipes measuring 290 × 12 × 21600-22600 mm, longitudinal flaws were 1400-1600 mm long on one from the seed end, 1300 and 1700 mm long on one side of the pilgrim flaw head, and on one pipe whips with a boron content of 2.85% transverse flaws were in the middle part at a length of 700 mm, which led to the loss of 3 krats in length. For redistribution, 17 krats were shipped. In the process of redistribution (boring and turning), 3 cracks were rejected: of them 1 time for external captures and small cracks, and 2 cracks for internal captures, displaying the wall thickness beyond the negative tolerance field of 5.0 mm. The expenditure coefficient of metal for steel 04X14T5R3F-Sh (the ratio of the mass of a given metal in production to the mass delivered to hexagonal billet pipes) for the conversion pipes of this batch was 3.385. According to the proposed technology, 5 hollow ingot blanks with a size of 450-460 × ext. 275-280 × 3000-3100 mm were set into production, with soft iron being melted to the bottom of the hollow ingot blanks with a size of 120-140 mm, to a shrink part of 300 -310 mm, which were heated to a temperature of 1030-1040 ° C and rolled with the bottom ends forward into conversion pipes measuring 290 × 12 × 25900-26900 mm. Rolling of conversion tubes was carried out in accordance with the claims. As a result, from 5 redacting lash tubes measuring 290 × 12 × 25900-26900 mm, 25 krat tubes 5100-5800 mm long were obtained, the long lengths of which were from the pilgrim heads and seed ends, i.e. with carbon ends. Of the 25 pipe-crats, one in the middle part of the krat-billet had transverse flaws along a length of 800 mm, which led to the loss of one scrap along the length. For the subsequent redistribution, 24 krats were dispatched. In the process of redistribution (boring and turning), 3 krats were rejected: of which 2 krats for external captures and 1 time for internal captures, displaying the wall thickness beyond the negative tolerance field of 5.0 mm. The expenditure coefficient of metal for steel grade 04X14T5R3F-Sh in the manufacture of hexagonal tubes of this batch was 2.604, i.e. for each ton of hexagonal billets, metal savings of 781 kg were obtained.

Thus, according to the proposed method, in the production of a pilot batch of conversion pipes of 290 × 12 mm in size in pipe rolling plants with pilgrim mills from ingot blanks of 450–460 × in. 275–280 × 3000–3100 mm in size from boron with a high content of boron from 2.64 to 2.85% (04Х14Т5Р2Ф-Ш), a decrease in the expenditure coefficient of metal for steel 04Х14Т5Р3Ф-Ш was obtained during the redistribution of a hollow ingot-billet - a conversion pipe-billet - a hexagonal pipe-billet of 781 kg per ton of hexagonal pipes - blanks on a turnkey basis 257 + 2.0 / -3.0 × 6 + 2.0 / -1.0 × 4300 + 80 / -30 mm.

Claims (1)

Method for the production of hexagonal billet pipes of size 257 + 2.0 / -3.0 × 6.0 + 2.0 / -1.0 × 4300 + 80 / -30 mm for compacted storage and transportation of spent nuclear fuel, including electroslag casting remelting of hollow ingots of 470 ± 5 × vn. 270 ± 5 × 3050 ± 50 mm in size from 04H14T5R2F-Sh low-ductility steel with boron content from 2.0 to 3.0% with bottom and shrinkage parts from carbon steel grades, the height of which, respectively from 0.04 to 0.05 and from 0.09 to 0.10 of the total height of hollow ingots, which form pilgrim heads and seed during rolling of conversion tubes end ends, turning and boring of ingots from the bottom side into hollow ingots-blanks of size 455 ± 5.0 × ext. 280 ± 5.0 × 3050 ± 50 mm, their heating to a temperature of 1030-1050 ° C and rolling into conversion tubes - whips of 290 × 12 × 25900-27000 mm in size on mandrels with a diameter of 264/265 mm with an extract of µ from 9.32 to 10.00 and compression in diameter Δ from 35.1 to 36.5%, removal of technological waste - pilgrim heads and seed ends with leaving sections of pipes made of plastic carbon steel with a length of 500-700 mm, after which the whip pipes are cut on a hot cutting saw into cutting tubes with a length of 10800 ± 200, 102 00 ± 100 mm and the remainder, the first and third transfer pipes are set for warm dressing with carbon steel grades, the first transfer pipe is cut from the side of carbon steel into blanks 5500 ± 200 mm long and the remainder, the second, are cut into two blanks of equal length, bored and turned into billet pipes measuring 284.75 × 6.0 + 2.0 / -1.0 mm, drill holes for the pulling chain for warm profiling in sections made of plastic carbon steel grades, profiled into hexagonal goods billet pipes Niemi ends of steel ductile carbon grades prior to heat treatment.