RU2470725C1 - METHOD OF MAKING 290×12 mm-TUBE STOCK FROM OF SOLID INGOTS FROM ELECTROSLAG REMELTING OF 04×14T5P2"Ф-Ш" -GRADE LOW-DUCTILE STEEL - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: proposed method comprises electroslag remelting of ingots from 04X14T5P2"Ф-Ш"-grade low-ductile steel with boron content of 2.0-3.0% and bottom and shrinkage parts from ductile carbon steels, turning said ingots to produce billets wherein through central bore is drilled, and heating them to 1040-1060°C. First, said ingots are pierced at helical rolling stand. Then, they are rolled at Pilger stand to tube sections to cut off process wastes so that ductile carbon tube 500-600-mm-long ends are made on dummy ingot and Pilger head side. Then, they are straightened and cut into multiple length tube stock and ends. Now, they are bored and turned to cylindrical tubes to be shaped to hexagonal tube billets. Note here that billet sizes and machining conditions are specified for all machining steps.

EFFECT: decreased wastes and ruled out rejects.

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Description

The invention relates to pipe production, in particular to a method for the production of pig tubes of size 290 × 12 × 25600-27700 mm from ingots-blanks of electroslag remelting of low-plastic steel grade 04X14T5R2F-Sh with boron content from 2.0 to 3.0% for the manufacture of hexagonal pipes - preparations of size 257 + 2.0 / -3.0 × 6.0 + 2.0 / -1.0 × 4300 + 80 / -30 mm for compact storage and transportation of spent nuclear fuel.

The closest in technical essence and the achieved result is a method of production of conversion pipes for the manufacture of hexagonal billet pipes of size for compacted storage and transportation of spent nuclear fuel, including the production of ingots from the low-plastic boron-containing steel by electroslag remelting, the bottom and shrinkage parts of which form during the conversion of the conversion pipes Pilgrim head and seed end, cast from ductile carbon steel grades, ingots bore and grind they are cast into ingot billets, ingot billets are heated to a plasticity temperature of 1040-1060 ° C, while removing technological waste - pilgrim heads and seed ends from plastic carbon steel grades, sections of pipes made of plastic carbon steel grades of 500-700 mm in length are left after cutting lashing pipes into two pipes of equal length or multiples of the length of the billet specify pipes for subsequent warm dressing in a six-roll straightening machine with ends made of plastic carbon steel grades, the ends of the pipe blanks made of plastic lerodistyh steels removed before the heat treatment with the performance of all subsequent operations of the process.

(RU 2317865, B21B 21/04, published 02.27.2008)

The main disadvantages of this method is that the known method extends to the production of conversion tubes from hollow bimetallic ingots-blanks ESR with a boron content of 1.3-1.8% and does not solve the technological issues of production of conversion tubes from solid ingots from steel 04X14T5R2F-Sh with boron content from 2.0 to 3.0%.

The objective and technical result of the invention is a method for the manufacture of conversion pipes of 290 × 12 × 25600-27700 mm in size from solid electroslag remelting ingots from low-grade steel grade 04X14T5R2F-Sh with a boron content of 2.0 to 3.0% for the manufacture of hexagonal tube blanks 257 + 2.0 / -3.0 × 6.0 + 2.0 / -1.0 × 4300 + 80 / -30 mm for compact storage and transportation of spent nuclear fuel. EFFECT: method allows to manufacture long lash pipes of increased length from low-ductile steel with boron content from 2.0 to 3.0%, to reduce the proportion of process wastes (seed ends, pilgrim heads and defective sections of lash pipes), reduce flaw defects on seed the ends and pilgrim heads, reduce the expenditure coefficient of the metal during the redistribution of the ingot - ingot-billet - conversion pipe-billet - hexagonal pipe-billet.

The technical result is achieved in that a method for the production of pig tubes of size 290 × 12 mm from solid ingots of electroslag remelting of low-ductility steel grade 04X14T5R2F-Sh with boron content from 2.0 to 3.0% for the manufacture of hexagonal tube blanks with a 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 are turned by turning the outer surface of the electroslag remelting ingots to remove casting defects to produce ingots-blanks, drilling central hole by heating ingots-blanks, piercing ingots-blanks in a cross-helical rolling mill into sleeves, rolling sleeves on a pilgrim mill in a whip pipe, by cutting a hot-cutting saw of technological waste - pilgrim heads and seed ends, by cutting conversion tubes in the form of whips by straightening pipes on a six-roll straightening machine using the temperature of rolling heating, by cutting pipes for warm profiling into hexagonal tubes-blanks, while ingots of size are cast by electroslag remelting 500 × 1825 ± 25 mm with boron content from 2.0 to 3.0%, the bottom and shrinkage parts of which are in height, respectively from 0.04 to 0.05 and from 0.12 to 0.13 of the total height of the ingots carbon steel grades that form seed ends and transfer heads during rolling of pig tubes, ingots are machined into ingots-blanks of size 485 ± 5 × 1825 ± 25 mm, a through hole is drilled through a central hole with a diameter of 100 ± 5.0 mm, heated to a temperature of 1040-1060 ° C, flashed in a cross-helical mill into sleeves of size 470 × ext. 295 × 2900-3100 mm with a diameter of Δ from 2.1 to 4.1 % and a hood µ from 1.61 to 1.68, the sleeves are rolled on a pilgrim mill in a whip pipe measuring 290 × 12 × 25600-27600 mm with a hood of 10.03 and a diameter fit Δ = 37.7%, from tubes lashes with a hot cutting saw cut off technological waste - pilgrim heads and seed ends made of plastic carbon steel grades, lash pipes with a hot cutting saw are cut into multiple length pipes and residue, leaving the carbon ends of the pipes from the seed side and the pilgrim head 500-600 mm long, moreover, the first multiple conversion pipe is cut from the end from carbon steel to a pipe with a length of 5300 ± 50 mm and the remainder, the second is cut into two pipes of equal length, bored and turned into cylindrical billet pipes for profiling into hexagonal billet pipes.

The method can be illustrated by the following example.

10 ingots (5 heats) of boron-containing steel grade 04X14T5R2F-Sh, obtained by electroslag remelting with a boron content of 2.63 to 2.89, were set in production. The ingots were divided into two parts with equal boron content. Three ingots with a size of 480 × 100 × 1675-1700 and two hollow ones with a size of 460 × 100 × 1725-1750 mm had bottom and shrink parts, which, when rolling the conversion tubes, formed pilgrim heads and seed ends made of plastic carbon steel grades. Then the ingots were bored and turned into ingot billets, the ingot billets were heated to a plasticity temperature of 1040-1060 ° C, and when removing technological waste - pilgrim heads and seed ends from plastic carbon steel grades, sections of pipes made of plastic carbon steel grades of 500- 700 mm After cutting the lash pipes into two pipes of equal length or multiple to the length of the billet, the pipes were set for warm straightening in a six-roll straightening machine with plastic carbon steel grades and then the ends of plastic carbon steel billets were removed before heat treatment with all subsequent operations on the technological process.

In the process of preliminary acceptance, three pipe-cracks were rejected for flaws - rolled defects: two cracks from the seed end, and the third crack from the pilgrim head. For the machining - turning, boring and subsequent profiling, 17 krats were shipped, of which two more krats were rejected during the machining process - one on the outer film and transverse cracks, and the second on the inner film, taking the wall thickness out of the negative tolerance 5, 0 mm Of the redistributed pipes obtained in a known manner, 15 hexagonal tubes-blanks with a total mass of 2.775 tons were made. The average expenditure coefficient of the metal for the pipes of this batch was 3.980.

Five ingots of low-plastic steel grade 04X14T5R2F-Sh with a boron content of 2.63 to 2.89 with a total weight of 12.458 tons were cast with dimensions of 500 × 1825 ± 25 mm with a boron content of 2.0 to 3.0%, with bottom and shrinkage parts of ingots with heights from 0.04 to 0.05 and from 0.12 to 0.13 of the total height of the ingots, respectively, were cast from plastic carbon steel grades forming seed ends and conversion heads during rolling of the transfer pipes. Then, the ingots were machined into ingot blanks with a size of 485 ± 5 × 1825 ± 25 mm, drilled through them through a central hole with a diameter of 100 ± 5.0 mm, heated to a temperature of 1040-1060 ° C, stitched in a cross-helical rolling mill into sleeves of size 470 × ext. 295 × 2900-3100 mm with a fit in diameter Δ from 2.1 to 4.1% and a hood µ from 1.61 to 1.68. The sleeves were rolled on a pilgrim mill to a whipping pipe of a size 290 × 12 × 26000-27000 mm with an exhaust hood of 10.03 and a diameter fit Δ = 37.7%. The mass of ingot billets for steel 04X14T5R2F-Sh was 10.339 tons. Technological waste was cut off from lash pipes by a hot-cutting saw — pilgrim heads and seed ends made of plastic carbon steel grades. Then, the lash pipes were cut with a hot cutting saw into cutting pipes of multiple lengths and the remainder, leaving the carbon ends of the pipes from the seed side and the pilgrim head 500-600 mm long, the first multiple transfer pipe being cut from the end side of carbon steel into a pipe of 5300 ± 50 length mm and the remainder, the second was cut into two pipes of equal length, bored and turned into cylindrical billet pipes for profiling into hexagonal billet pipes.

In the process of preliminary acceptance, one pipe-krat was rejected according to flaws in the center of the third slope - defects in the rental. 24 machining pipes were shipped for machining, turning, boring and profiling, of which two machining pipes were rejected during machining: one on the outer film and transverse tearing, and the second on the inner film, removing the wall thickness outside the negative field tolerances. After profiling, 22 hexagonal workpieces with a total weight of 4.070 tons were accepted as fit. The average expenditure coefficient of the metal for pipes of this batch was 3.061, and for steel 04X14T5R2F-Sh-2.540.

Data on rolling and delivery of conversion pipes are given in the table.

The table shows that when implementing the method according to the invention, a reduction in the expenditure coefficient of metal on steel 04X14T5R2F-Sh was achieved during the redistribution of the ingot - ingot-billet - conversion pipe - hexagonal billet pipe by 1440 kg for each ton of hexagonal billet pipes.

At the same time, the number of end defects at the seed ends in the form of cracks and flaws was reduced, the cost of marketable hexagonal pipes made of steel 04X14T5R2F-Sh was reduced, and the reliability of the shelving for storing spent nuclear fuel was increased.

Claims (1)

Method for the production of conversion tubes 290 × 12 mm in size from solid ingot blanks for the manufacture of hexagonal blanks in size 257 + 2.0 / -3.0 × 6 + 2.0 / -1.0 × 4300 + 80 / -30 mm for compacted storage and transportation of spent nuclear fuel, including casting by electroslag remelting of ingots of size 500 × 1825 ± 25 mm from low-ductility steel grade 04X14T5R2F-Sh with boron content from 2.0 to 3.0%, with bottom and shrink parts from plastic carbon steel grades, the height of which is respectively from 0.04 to 0.05 and from 0.12 to 0.13 of the total height of the ingots, image when rolling redistribution tubes, seed ends and pilgrim heads, turning the outer surface of electroslag remelting ingots to remove casting defects to produce ingot blanks of 485 ± 5 × 1825 ± 25 mm in size, in which a through central hole with a diameter of 100 ± 5.0 mm is drilled , they are heated to a temperature of 1040-1060 ° C, stitched in a transverse helical rolling mill into sleeves of size 470 × ext. 295 × 2900-3100 mm with a diameter setting Δ from 2.1 to 4.1% and a hood µ from 1 , 61 to 1.68, sleeves are rolled on a pilgrim mill in a pipe-lash with a size of 290 × 12 × 25600-27600 mm with an exhaust hood of 10.03 and a diameter of Δ = 37.7%, technological waste is cut from lash pipes by a hot cutting saw, leaving the ends of pipes made of carbon steel grades 500-600 mm long with the sides of the seed and the pilgrim head, straighten the lash pipes on a six-roll straightening machine using the rolling temperature, a hot cutting saw is cut into pigs of multiple lengths and the remainder, the first multiple pigs being cut from the end side of plastic carbon steel n tube length of 5300 ± 50 mm and the residue, a second tube is cut into two equal lengths and bore grind a cylindrical billet for pipe profiling hex-tube preform.