RU2502571C1 - Method of making steel pipes of size 290x11-12 mm using pipe rolling plant "тпу" 8-16" with pilgrim mills from low-ductile steels of grades 04x14t3p1"ф-ш" and 04x14t5p2"ф-ш" - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention can be used for production of hexahedral pies for sealed storage in nuclear power station ponds and transportation of used nuclear fuel. Cast produced by electroslag remelting, turned to remove foundry defects, heated to ductility storage and pierced at cross-rolling mill to sleeves. Mandrel with ring is fitted at pilgrim mill mandrel head. Cylindrical carbon jar washer is fitted on mandrel to be fitted in said sleeve. Then, tapered cylindrical carbon jar washer is fitted on the mandrel and centered relative to mandrel axis by taper section of carbon jar washer. Assembled sleeve is shaped at variable-profile gages to steel pipe with seed end and pilgrim head fitted on carbon jar washers.

EFFECT: lower metal input and higher efficiency.

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Description

The invention relates to pipe rolling production, in particular to a method for the production of conversion pipes with a size of 290 × 11-12 mm using a TPU 8-16 "pipe rolling installation with piligrim mills of low-plastic steels 04X14T3R1F-Sh and 04X14T5R2F-Sh for the manufacture of hexagonal tubes for compacted storage in the pools for holding nuclear power plants and for transporting spent nuclear fuel with the removal of pilgrim heads and seed ends on carbon ring liners, and can be used in the manufacture of conversion tubes b on pipe rolling plants with pilgrim mills.

In the process of rolling pipes at TPU with pilgrim mills, technological waste is generated in the form of pilgrim heads and seed ends, the mass of which, depending on the geometric dimensions of the pipes, per ton is from 135 to 150 kg (F.A. Danilov, A.Z. Gleiberg, VG Balakin. // Hot rolling of pipes. Moscow. Metallurgy Publishing House, 1962. p.296).

In the pipe industry, there is a known method of preparing billets for rolling pipes without pilgrim heads on a pilgrim mill, which includes separate heating to the ductility temperatures of billets made of alloy steel grades and alloys and nozzles made from carbon steel grades, piercing of billets in a cross-helical rolling mill in sleeves and sequentially planting them on the mandrel to the junction of the ends. Rolling is carried out before the formation (removal) of the pilgrim head on the nozzle (carbon ring). After rolling, the underlay ring (pilgrim head) and pipe are removed from the mandrel. The pipe is directed along the live roll (exit chute) to the hot cutting saw to remove the seed end and cut the pipe (if necessary) into multiple lengths, and the pilgrim head is transferred by crane to boxes with carbon metal scrap. The preparation of the next sleeve for rolling is carried out by the method described above (USSR Authors Certificate No. 430908, Cl. B21B 21/00. 1972).

The disadvantage of this method of preparing sleeves for pilgrim rolling without pilgrim heads is that it focuses on the technology of rolling commodity and conversion tubes from alloyed hard-to-form steel grades and alloys with an increased coefficient of linear expansion without pilgrim heads, and when rolling conversion tubes measuring 290 × 11- 12 mm of low-plastic boron-containing steels during the rolling (running-in) of the pilgrim heads from the underlay carbon rings, the lash pipes are discharged from the mandrel, which in turn leads to to increased trimming of pipe ends due to unrolled “riots” - thickening of the pipe wall by caliber outlets and can lead to breakage of the safety bolts and spindles of the pilgrim mill.

In the pipe industry, there is also a method of preparing billets (sleeves) for pilgrim rolling of pipes, which includes separate heating of billets of alloy steel and alloys and carbon rings with carbon rings, the outer diameter of which is 1.15-1.25 of the sleeve diameter . Moreover, in order to slow down the temperature of the ring and reuse it with multiple sleeves, the surface of the ring is covered with heat-insulating material (USSR Authors Certificate No. 732043, Cl. B21B 21/00. 1980).

A disadvantage of the known method of preparing sleeves for pilgrim rolling of pipes is not the manufacturability of coating the underlay carbon rings of heat-insulating fusible materials and, as the above analogue, it does not solve the problem of dropping tubing from the mandrel when running the pilgrim heads and reducing the consumption of boron-containing steels for the formation of pilgrim heads. This method may be acceptable only when rolling pipes from titanium-based alloys.

In the pipe industry, there is also a known method for preparing sleeve blanks from alloyed steel grades and alloys for pilgrim rolling of pipes, including heating sleeve blanks and nozzles made of low-cost carbon steel grades — lining carbon rings whose outer diameter is larger than the diameter of the sleeves and having a cylindrical and conical sections, the sizes of which are determined from the expressions L _to = (0.6-0.8) D _g , L _TSU = (0.35-0.4) D _g , L _k.u. = (0.25-0.4) D _g , D _cu = (1.15-1.3) D _g , D _c.u. = (1.0-1.1) D _g , where D _g is the diameter of the sleeve, mm; L _k is the total length of the carbon ring, mm; L _c.u. - the length of the cylindrical section of the ring, mm; L _k.u. - the length of the conical section of the ring, mm; D _c.u. - the diameter of the cylindrical section of the ring, mm; D _c.u. - the smallest diameter of the conical section of the ring, mm, with an increase in the diameter of the cylindrical section of the ring, the length of the conical section increases from 0.25 to 0.4 D _g , and the conical section of the pipe with a smaller base abuts the end of the sleeve (patent RU No. 2207199, Cl. B21B 21 / 00, 06/27/2003).

This method provides multiple use of carbon linings, elimination of mandrel tightening when rolling tubes of high alloy steel grades and alloys with an increased coefficient of linear expansion, full run-in (removal of pilgrim heads on carbon metal), but also, as the above analogues, does not solve the problem of reducing consumption boron-containing steels for the formation of seed ends.

The closest technical solution is the method of pilgrim rolling, comprising inserting the mandrel into the sleeve, having a section with increased taper under the mandrel head for centering the rear end of the sleeve, putting on the sleeve of the sleeve, and then a conical carbon ring, the conical part of which centers the front end of the sleeve with respect to the axis of the mandrel and the deformation of the composite billet rolls with a variable caliber profile into commodity pipes (patent RU No. 2346766, Cl. B21B 21/00, 02.20.2009).

This method of pilgrim rolling is aimed at reducing the transverse difference of the seed ends of the pipes, i.e. to a partial reduction in their length and does not solve the problem of removing the pilgrim heads during rolling of conversion tubes from boron-containing steel grades.

The objective of the proposed method for the production of conversion pipes 290 × 11-12 mm in size on TPU 8-16 "with pilgrim mills from ingots-blanks of electroslag remelting of low-plastic steels of grades 04Х14Т3Р1Ф-Ш and 04Х14Т5Р2Ф-Ш for manufacturing hexagonal tubes-blanks for compacted storage in holding pools A nuclear power plant and transportation of spent nuclear fuel is the complete rolling (running-in) of the pilgrim heads and the front ends of prefabricated sleeve blanks into conversion pipes of 290 × 11-12 mm in size from boron-containing steel grades 04X14T3R1F-Sh and 04 14T5R2F-SH and reset exception pipe-lashes with the mandrel.

The technical result is achieved by the fact that in the known method for the production of pig tubes with a size of 290 × 11-12 mm using a TPU 8-16 "tube mill with pilgrim mills made of low-plastic steel grades 04X14T3R1F-Sh and 04X14T5R2F-Sh, including ingots casting by electroslag remelting, turning ingots on the outer surface to remove casting defects to produce ingot billets, heating the ingot billets to a plasticity temperature, piercing ingot billets in a cross-helical rolling mill s, charging the mandrel with the mandrel ring to the mandrel head of the pilgrim mill, dressing the mandrel of the carbon ring on the mandrel with a cylindrical section to the mandrel and tapered to the end of the sleeve, inserting the mandrel into the sleeve, putting on the mandrel of the carbon ring made in the form of a cylinder with a conical portion , centering the conical section of the liner carbon ring of the front end of the sleeve relative to the axis of the mandrel and the deformation of the combined sleeve in rolls with a variable caliber profile in the transfer tube with the removal of the equal end and the pilgrim head on the underlay carbon rings.

Comparative analysis with the prototype shows that the inventive method for the production of pig tubes with a size of 290 × 11-12 mm using a TPU 8-16 "tube mill with pilgrim mills made of low-plastic steel grades 04Х14Т3Р1Ф-Ш and 04Х14Т5Р2Ф-Ш, differs in that after putting the mandrel in the sleeve, on the mandrel wear a carbon liner made in the form of a cylinder with a conical section, center the cone section of the carbon ring of the liner front end of the liner relative to the axis of the mandrel and the deformation of the team a second sleeve rolls with varying caliber profile in a pipe pig breeding and seed end pilger die on skid carbon ring. Thus, these differences lead to the conclusion according to the criterion "Inventive Level".

Comparison of the proposed method not only with the prototype, but also with other technical solutions in the art did not allow them to identify signs that distinguish the claimed method from the prototype, which corresponds to patentability "inventive step".

The proposed method for the production of conversion pipes with a size of 290 × 11-12 mm using a TPU 8-16 "tube rolling unit with pilgrim mills made of low-plastic steels of grades 04X14T3R1F-Ш and 04Х14Т5Р2Ф-Ш consists in charging a mandrel with a mandrel ring to the mandrel head of the pilgrim mill , dressing on the mandrel of the underlay carbon ring with a cylindrical section to the mandrel ring, and tapered to the end face of the sleeve, inserting the mandrel into the sleeve, dressing on the mandrel of the underlay carbon ring made in the form of a cylinder with a conical tkom centering tapered portion the slip ring carbon front end of the sleeve with respect to the axis of the mandrel and deformation of the modular sleeve in a variable profile rolls with caliber tube with pig breeding and seed end pilger die on skid carbon ring.

Determination of the geometric dimensions of the liner carbon rings, the method of tilting and feeding the prefabricated sleeve blanks to the deformation zone will allow the rolling of the prefabricated sleeve blanks on the pilgrim mills into conversion pipes measuring 290 × 11-12 mm with fixed feed rates from seed to full break-in (removal) seed ends and pilgrim heads to carbon metal without dividing them into components, in-line removal of pilgrim heads and seed ends from carbon metal with a hot cutting saw, i.e. . the exception of the operation of removing carbon rings from the mandrel and transporting them by crane to boxes for scrap metal, which will reduce the consumption of boron-containing steels and increase the performance of pilgrim mills.

The method has been tested and implemented on a pipe-rolling installation with 8-16 pilgrim mills of OAO ChTPZ when rolling redacting pipes 290 × 12 mm in size from steel grade 04X14T5R2F-Sh with a boron content of 2.42-2.67% from ingots-blanks ESH size 470 × 100 × 1750 and 470 × 100 × 1700 mm.

According to the existing technology, pipes of this size from this steel grade must be rolled in rolls with a caliber of 295 mm with underlay cylindrical carbon rings of size 480xvn. 320 × 250 mm for the removal of pilgrim heads on carbon metal and conical underlay carbon rings with an outer diameter in the cylindrical part of 460-470 mm and an inner diameter of 320 mm. The minimum outer diameter of the conical part of the underlay carbon ring is 285 mm. Converted pipes of 290 × 12 mm in size from EAW ingots-blanks of 470 × 100 × 1750 mm in size according to the existing technology were produced in two ways, namely using one cylindrical carbon ring for the extraction of pilgrim heads (USSR Authentic Certificate No. 430908) and two rings for the removal of pilgrim heads and seed end (RF patent No. 2346766). When rolling the conversion pipes 290 × 12 mm in size according to existing methods, 20 ESH ingots of steel grade 04X14T5R2F-Sh with a boron content of 2.42-2.67% of 470 × 100 × 1750 mm in size (10 ingots for each option). Billet ingots were heated in a methodical furnace to a temperature of 1060-1070 ° C and stitched in a transverse helical mill on a mandrel with a diameter of 280 mm in sleeves of 470hvn in size. 295 × 2700 mm. The underlay carbon rings were heated in another methodical furnace to a temperature of 1260-1270 ° C. The first 10 ingot billets with a total mass of 22.74 tons were rolled using cylindrical rings to bring the pilgrim heads onto plastic carbon rings. When running the pilgrim heads in all cases, the scouring of the lash tubes from the mandrel was observed, which did not allow an additional tilting and rolling of the whiskers formed at the last feeds of the sleeves into the deformation zone, which led to the cutting of the rear ends of the lash tubes at a length of 1100-1300 mm ( the average trim length was 1200 mm). In order to avoid the formation of flaws at the front (seed) ends of the transfer pipes, the seed was produced on a wall of 14-14.5 mm. As a result, the average length of the conversion pipe at the rental was 26500 mm, from which the hot ends were removed with a hot cutting saw with a length of 800 mm and the ends from the pilgrim heads of an average length of 1200 mm. Pipes 24,500 mm long were cut with a hot-cutting saw into two pipes of equal length. On one lash pipe there were flaws on the side of the pilgrim head, and on the other on the side of the seed, which led to the loss of 2 krats. The pipes were straightened on the correct machine, accepted as conditionally suitable, and sent to workshop No. 5 for processing into hexagonal pipes. Of these pipes, 38 krats were marked in workshop No. 5. In the process of machining and profiling, three more katas were rejected: one kat on the outer captivity, the second kat on the inner captivity, and the third on the notch (marriage of workshop No. 5). From this batch of redistribution pipes, 35 hexagonal billet pipes with a total mass of 6.48 tons were commissioned. The expenditure coefficient of metal for the pipes of this batch amounted to 3.509.

The second 10 ingot billets with a total weight of 22.25 tons were rolled using cylindrical rings to bring out the pilgrim heads and seed ends onto plastic carbon rings. Lining rings were used to remove the seed ends according to RF patent No. 2346766. When running the pilgrim heads in all cases, the scouring of the lash tubes from the mandrel was observed, which did not allow for additional tilting and rolling of the whiskers formed at the last feeds of the sleeves into the deformation zone, which led to the cutting of the rear ends of the lash tubes at a length of 1100-1200 mm ( the average trim length was 1150 mm). The seed was produced stably, the carbon rings did not separate from the lash pipes, which allowed the rolling mill to be rolled onto the 12 mm wall. The average length of the transfer pipes in the gutter of the pilgrim mill was 27,000 mm, from which the ends from the pilgrim heads 1100-1200 mm long and the seed ends 800 mm long were removed from the hot cutting saw. The average length of the pipes in the gutter of the pilgrim mill, taking into account the trimming, was 25500 mm. Pipes 25,500 mm long with a hot-cutting saw were cut into two pipes of equal length. There were flaws on the two lash pipes from the pilgrim heads, which led to the loss of 2 krats. The pipes were straightened on the correct machine, accepted as conditionally suitable, and sent to workshop No. 5 for processing into hexagonal pipes. Of these pipes, 38 krats were marked in workshop No. 5. In the process of machining and profiling, two more cracks were rejected: one time on the external captivity, and the second time on the internal captivity (marriage of workshop No. 1). Of this batch of redistribution pipes, 36 hexagonal billet pipes were delivered with a total weight of 6.67 tons. The expenditure coefficient of metal for the pipes of this batch amounted to 3.336.

A third batch of 10 ingot blanks with a total mass of 22.65 tons was rolled in accordance with the claims. To remove the seed ends used washers according to RF patent No. 2346766. When running the pilgrim heads in cases, the sliding of the lash tubes from the mandrel did not occur. Carbon rings were removed by a hot cutting saw.This made it possible to tilt and roll over the whiskers until the pilgrim heads were completely removed to carbon metal, which in turn made it possible to reduce the lengths of the back ends of the lashing pipes cut into waste by 800 mm. Reducing the length of the cut back ends of the pipe-lashes due to the difference and longitudinal flaws makes it possible to reduce the length of the ingots of the workpieces by 50 mm. In the process of rolling 10 ingot billets on a pilgrim mill, 20 pipes or 40 krats were obtained. Marriage of tubrates in workshop No. 1 was absent. In shop No. 5, 40 krats were sent to their further processing into hexagonal tubes. In the workshop No. 5 during processing three rejects were rejected: one along the outer captivity, the second along the inner captivity, and the third along the notch walls, displaying the wall thickness beyond the negative tolerance field. Accepted 37 hexagonal billets with a total weight of 6.85 tons were usable. The expenditure coefficient of the metal for the pipes of this batch was 3.307, i.e. a decrease in the expenditure coefficient relative to option No. 2 of the existing technology by 29 kg per ton of hexagonal workpieces was obtained.

Experimental industrial rolling of a batch of conversion pipes according to the proposed method showed the possibility of reducing the height of the ingot blanks ESR by 50-60 mm. A fourth batch of 10 ingot blanks measuring 470 × 100 × 1700 mm with a total weight of 22.05 tons was rolled in accordance with the claims. When running the pilgrim heads in cases, the sliding of the lash tubes from the mandrel also did not occur. Carbon rings were removed with a hot cutting saw. In the process of rolling 10 ingot billets on a pilgrim mill, 20 pipes or 40 krats were obtained. Marriage of pipe-crats in workshop No. 1 was absent. In shop No. 5, 40 krats were sent for further processing into hexagonal tubes. In the workshop No. 5 during processing two rejects were rejected: one along the outer captivity, and the second along the inner captivity, displaying the wall thickness beyond the negative tolerance field. 38 hexagonal tube blanks with a total weight of 7.03 tons were accepted as suitable. The expenditure coefficient of the metal for the pipes of this batch amounted to 3.137, i.e. a reduction in the expenditure coefficient of the metal of expensive boron-containing steel grade 04X14T5R2F-Sh, relative to option No. 2 of the existing technology, by 199 kg per ton of hexagonal workpieces was obtained.

After the first two strokes (feeds) of the prefabricated sleeves into the deformation zone, the underlay carbon rings for removing the seed ends and pilgrim heads tightly entered the sleeves, forming one monolithic pre-assembled sleeve. The carbon fiber seed tips and pilgrim heads were removed by a hot cutting saw, i.e. without reducing the performance of the pilgrim mill. Data on rolling of conversion pipes 290 × 12 × 22000-24100 mm in size from 04Kh14T5R2F-Sh steel ingots with a boron content of 2.42-2.67, cast at ZMZ OJSC and rolled at 8-16 "TPU with pilgrim mills Chelyabinsk Pipe Rolling Plant, according to the existing and proposed methods, and the production of turnkey hexagonal tubes-blanks of 257 × 6 × 4300 mm in size, are shown in Table 1.

Thus, the use of the proposed method for the production of conversion tubes from ESR ingots-blanks of low-plastic boron-containing steel grades 04Х14Т3Р1Ф-Ш and 04Х14Т5Р2Ф-Ш on pipe-rolling plants with pilgrim mills will allow the rolling process of conversion tubes with the complete removal of seed ends and piligid carbon rings , to exclude the possibility of dumping monolithic sleeves-blanks from boron-containing steels when the pilgrim heads are completely run in, and, therefore, to reduce the expenditure the coefficient of metal during the redistribution of the ESR ingot-billet - conversion pipe - hexagonal billet-pipe, increase the performance of the pilgrim installation by reducing the auxiliary time for removing the underlay carbon ring from the mandrel and transporting it by crane to boxes with metal waste, and therefore reduce the cost of commodity hexagonal billet pipes.

Claims (1)

Method for the production of conversion pipes 290 × 11-12 mm in size using a TPU 8-16 "tube rolling unit with pilgrim mills made of low-plastic steel grades 04X14T3R1F-Sh and 04X14T5R2F-Sh, including ingots casting by electroslag remelting, turning the ingots on the outer surface before removing the defects Origin of production of ingots-billets, heating of ingots-billets to a plasticity temperature, piercing of ingots-billets in a cross-helical rolling mill into sleeves, charging of a mandrel with a mandrel ring to the mandrel head pi a ligrim mill, dressing on a mandrel of a cylindrical underlay carbon ring, inserting a mandrel into a sleeve, dressing on a mandrel of a support carbon ring made in the form of a cylinder with a conical section, the underlay carbon ring being put on the mandrel with a cylindrical section to the mandrel ring, and a conical section in the side of the sleeve , centering the conical section of the liner carbon ring of the front end of the sleeve relative to the axis of the mandrel and the deformation of the combined sleeve in rolls with a variable caliber profile in the redistribution pipe with the withdrawal of the seed end and the pilgrim head on the underlay carbon rings.