RU2696801C1 - Method of production of rerolled pipes - Google Patents

Abstract

FIELD: valve industry.SUBSTANCE: invention relates to pipe production, in particular, to production of rerolled pipes with size of 290×12 mm on tube-forming installation 8-16ʺ with pilger mills from ingots-billets produced by cyclic electroslag remelting from low-alloy steel 04H14T3R1F-SH with boron content from 1.3 to 1.8 wt%, for production of hexahedral pipes-billets with "turnkey" size 257+2/-3×6+2/-1×4,300+80/-30 mm for compacted storage in NPP holding pools and spent nuclear fuel transportation, and can be used in production of pipes at pipe-rolling plants with pilger mills. Technical result is ensured by fact that ingot is cast by cyclic electroslag remelting method, turning ingot into ingot-billet, drilling central hole with diameter of 100±5.0 mm, heating ingot-billet to ductility temperature; inverting of ingot-billet in helical rolling mill into sleeves on mandrel, rolling of sleeves on pilger mill in pipe-thread, wherein in the helical rolling mill, the sleeves are being pierced on the mandrel with the size of the outer diameter and the drawing μ=1.67, and sleeves on pilger mill are rolled in tubes with crosswise outlet angle on polishing section 23–24° with drawing μ=7.99, diameter reduction Δ=34.1 % and with feeding of sleeves into deformation center at steady-state rolling process m=16.2–18 mm.EFFECT: exclusion of an ovality and a variance of a rerolled pipe, as well as partial or complete elimination of through flaws.6 cl

Description

The invention relates to pipe production, in particular, to a method for the production of conversion pipes of 290 × 12 mm in size on TPU 8-16ʺ with pilgrim mills from ingot blanks obtained by the method of cyclic electroslag remelting from low plastic steel 04X14T3P1F-Sh with boron content from 1.3 to 1.8 wt. %, for the manufacture of hexagonal tube blanks with a turnkey size of 257 + 2 / -3 × 6 + 2 / -1 × 4300 + 80 / -30 mm for compacted storage in the pools of nuclear power plants and transportation of spent nuclear fuel, and can be used in the production of pipes in pipe rolling plants with pilgrim mills.

A known method of manufacturing tube blanks for the manufacture of hexagonal sheath tubes of low-ductility steel with a boron content of 1.3-1.8%, including steel smelting, remelting into ingots, forging an ingot, piercing an ingot by drilling a central hole, heating it to a ductility temperature, piercing in a cross-helical rolling mill into sleeves, rolling sleeves in a pilgrim mill into preform tubes, cooling the preform tubes, cutting the preform tubes into two equal preforms, reheating them to the ductility temperature, piercing in sintering mill into sleeves, rolling in a pilgrim mill into conversion pipes and dressing them in a straightening machine at a temperature of at least 100 ° C, using the temperature of the rolling heat.

(RU 226133, B21B 21/00, B21B 21/04, published 03/27/2004)

The known method is quite time-consuming, since it includes two heating, two firmware, two rolling on a pilgrim mill and cutting of pipe blanks on the machines. In addition, rolling blanks on a pilgrim mill after cutting into equal parts leads to an increase in technological waste in the form of two seed ends and two pilgrim heads, and when seeding and rolling (rolling) the pilgrim heads, due to the low ductility of steel and lowering the temperature of the liner below temperature of ductility of steel is high probability of the formation of end defects in the form of longitudinal cracks and flaws in the length of 0.5-0.8 meters.

The closest technical solution is a method for the production of conversion pipes for the manufacture of hexagonal pipes from low plastic steels, including electroslag casting of an ingot, turning the ingot into a billet ingot, drilling a through central hole, heating to ductility temperature, piercing in a cross-helical rolling mill into sleeves with compression in diameter Δ from 2.17 to 4.26 and hood μ from 1.71 to 1.79, rolling the sleeves on a pilgrim mill with lining carbon rings into conversion tubes in rolls with ibrom 295 mm stretch μ = 8,65 and swaging diameter Δ = 35,6%.

The known method is also characterized by the fact that the rolling of the conversion pipes on the pilgrim mill is carried out in rolls with an angle of transverse release on the polishing section of 26-28 ° with the supply of sleeves into the deformation zone during the steady rolling process m = 15-16 mm, and rolling is performed with the edge of the sleeves -pipe at an angle of (45 ± 5) ° or (135 ± 5) °.

(RU 2511199, B21B 21/00, published 10.04.2014)

The disadvantages of this method is that the increased reduction in diameter of the ingots-billets in the cross-helical rolling mill of low-ductility steel grade 04X14T3R1F-Sh leads to the formation of defects on the outer surface in the form of flaws. In addition, when rolling sleeves made of low-plastic steel on a pilgrim mill with increased reductions in diameter, it leads to the appearance of rolled defects on the body of the transfer pipes: grids of tears or through flaws; moreover, when rolling conversion tubes in rolls, there is a high probability of the appearance of ovality and pipe spacing.

The objective of the invention is the elimination of ovality and raznenennosti conversion pipe, as well as partial or complete elimination of through flaws.

The technical result is achieved in that the method for the production of pig tubes includes casting an ingot by cyclic electroslag remelting, turning the ingot into an ingot ingot, drilling a central hole with a diameter of 100 ± 5.0 mm, heating the ingot ingot to a plasticity temperature; piercing a billet ingot in a cross-helical rolling mill into sleeves on a mandrel, rolling sleeves on a pilgrim mill in a whip pipe, and in a cross-helical rolling mill, sleeves on a mandrel are sewn into mandrels a size in size by outer diameter and a hood μ = 1.67, and the sleeves on the pilgrim mill are rolled into scouring tubes with a lateral outlet angle at the polishing section of 23-24 ° with an extract of μ = 7.99, a diameter compression Δ = 34.1% and with the sleeves being fed into the deformation zone during the steady rolling process m = 16.2-18 mm.

The technical result is also achieved by casting an ingot of size 455 × 1800 ± 25 mm from low-plastic steel grade 04X14T3R1F-Sh with boron content from 1.3 to 1.8%; turning the ingot into the ingot billet leads to a size of 440 × 1800 ± 25 mm; heating the ingot blanks is carried out to a ductility temperature of 1060-1090 ° C; in a cross-screw rolling mill, the ingot-billet firmware is driven into sleeves of size 440 × ext. 295 × 2965-3050 on a mandrel with a diameter of 280 mm; the sleeves on the pilgrim mill are rolled in a caliber of 295 mm in a whip pipe measuring 290 × 12 × 22000-22800 mm.

The invention can be illustrated by the following example.

It was obtained by the method of cyclic electroslag remelting (remelting with multiple change of electrodes in the process of ingot smelting) 10 ingots from steel 04Kh14T3R1F-Sh with boron content of 1.72-1.78 wt. %

After turning the ingots into ingot ingots and drilling the central holes with a diameter of 100 ± 5.0 mm, 5 ingot blanks with a size of 465 × 100 × 1650 mm (known method) and 5 ingot blanks with a size of 440 × 100 × 1800 mm were set into production method according to the invention). According to the method according to the invention, ingot billets with a total mass of 9.910 tons were heated in a method furnace to a temperature of 1060-1070 ° C and stitched in a cross-screw mill on a mandrel with a diameter of 280 mm in sleeves on a mandrel with a size of 440 × ext. 295 × 3000 mm size in size according to the outer diameter, with an extractor μ = 1.67. The sleeves are rolled on a pilgrim mill in a 295 mm caliber with a lateral outlet angle of 24 ° in a whip pipe measuring 290 × 12 × 22000 mm with a hood μ = 7.99, a diameter reduction of Δ = 34.1% and with the sleeves being fed into the deformation zone with the steady rolling process m = 18 mm.

The hot ends were removed from the lash pipes by the seed ends and incompletely run-in pilgrim heads. The lash pipes were cut into two pipes of equal length, the conversion pipes were straightened and accepted according to STP. 20 crates were sent for processing into hexagonal billets of turnkey size 257 + 2 / -3 × 6 + 2 / -1 × 4300 + 80 / -30 mm. When redistributing after machining, 2 cracks were rejected: one on the inner captivity and one on cuts during machining. Ovality and otnostennost krats not identified. Accepted 18 hexagonal billet pipes with a total weight of 3.330 tons were used. The expenditure coefficient of the metal was 2.976.

According to the known method, five ESR ingots-blanks with a size of 465 × 100 × 1650 mm with a total mass of 10,200 tons were heated in a methodical furnace to a temperature of 1060-1070 ° C and sewn in a cross-helical mill on a mandrel with a diameter of 280 mm in sleeves of size 450 × vn .295 × 2890 mm with compression in diameter Δ = 3.23%, with a hood μ = 1.75. The sleeves are rolled on a pilgrim mill in a 295 mm caliber with a lateral outlet angle of 28 ° in a whip pipe measuring 290 × 12 × 23000 mm with a hood μ = 8.65, a diameter reduction of Δ = 37.65% and with the sleeves being fed into the deformation zone with the steady rolling process m = 16 mm. The hot ends were removed from the lash pipes by the seed ends and incompletely run-in pilgrim heads. The lash pipes were cut into two pipes of equal length, the conversion pipes were straightened and accepted according to STP. In the process of acceptance, one time is rejected for flaw under the pilgrim head. 19 crates were sent for processing into hexagonal billets of turnkey size 257 + 2 / -3 × 6 + 2 / -1 × 4300 + 80 / -30 mm. When redistributing after machining, 3 cracks were rejected: one on the outer captivity, one on the inner captivity and difference, and one on the cuts during machining. Accepted 16 hexagonal billet pipes with a total weight of 2,960 tons were used. The expenditure coefficient of the metal was 3.446.

The method according to the invention in the production of conversion pipes measuring 290 × 12 × 22000 mm in pipe rolling plants with piligrim mills made of low-plastic steel grade 04X14T3P1F-Sh with boron content from 1.72 to 1.78%, a reduction in the expenditure coefficient of the metal during redistribution of the ingot - a conversion pipe - a hexagonal pipe - a workpiece of 470 kg per ton of hexagonal pipe-workpieces while increasing the productivity of the pilgrim mill ≈ 8-10% due to an increase in the supply of sleeves to the deformation zone.

Using the proposed method for the production of conversion pipes 290 × 12 mm in size on a pipe-rolling plant with pilgrim mills 8-16ʺ from ingots-blanks of electroslag remelting from low-ductility steel grade 04X14T3R1F-Sh with boron content from 1.3 to 1.8% for the manufacture of hexagonal pipes - turn-key blanks of 257 + 2.0 / -3.0 × 6 + 2.0 / -1.0 × 4300 + 80 / -30 mm for compact storage in the pools of nuclear power plants and transportation of spent nuclear fuel will reduce consumption metal through the use of optimal sizes of ingots wok and deformation parameters in cross-helical rolling mills and pilgrim mills, reduce the number of defects at the seed ends and the ends under the pilgrim heads in the form of cracks and flaws, eliminate the formation of flaws on the body of the conversion pipe-lashes, ovality and delta pipes, as well as increase the performance of the pilgrim mills, reduce the cost of commodity hexagonal tubes-blanks from steel 04Kh14T3R1F-Sh and 04Kh14T5R2F-Sh.

Claims (6)

1. Method for the production of pig tubes, including ingot casting by cyclic electroslag remelting, turning the ingot into a billet ingot, drilling a central hole with a diameter of 100 ± 5.0 mm, heating the billet ingot to a plasticity temperature, piercing the ingot billet in a cross-screw mill rolling in the sleeves on the mandrel, rolling the sleeves on the pilgrim mill in the whip tubes, characterized in that in the cross-helical rolling mill, the sleeves on the mandrel are stitched with a dimension of the size of the outer diameter and the hood μ = 1.67, and the sleeves are n and the pilgrim mill is rolled into scouring tubes with a lateral outlet angle at the polishing section of 23-24 °, with an extract of μ = 7.99, a compression in diameter Δ = 34.1% and with the supply of sleeves to the deformation zone with the steady rolling process m = 16.2-18 mm. 2. The method according to p. 1, characterized in that the ingot is sized 455 × 1800 ± 25 mm from low-grade steel grade 04X14T3R1F-Sh with boron content from 1.3 to 1.8%. 3. The method according to p. 1, characterized in that the turning of the ingot into the ingot billet lead to a size of 440 × 1800 ± 25 mm 4. The method according to p. 1, characterized in that the heating of the ingot-billet is carried out to a plasticity temperature of 1060-1090 ° C. 5. The method according to p. 1, characterized in that in the cross-helical rolling mill, the firmware of the ingot-billet is guided into sleeves 440 × in. 295 × 2965-3050 on a mandrel with a diameter of 280 mm. 6. The method according to p. 1, characterized in that the sleeves on the pilgrim mill are rolled in a caliber of 295 mm in a whip pipe measuring 290 × 12 × 22000-22800 mm.