RU2524459C1 - PRODUCTION OF 426×21-40 mm SEAMLESS HOT-ROLLED PIPES FOR STEAM BOILERS, STEAM PIPELINES AND MANIFOLDS OF PLANTS WITH HIGH AND SUPERHIGH STEAM PARAMETERS OF "10Х9МФБ-Ш"-GRADE STEEL - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: proposed method comprises ESR casting, turning the casts to ingots-billets to 600xvn.240x2100±50 mm and 600xvn.200x2100±50 mm. Said ingots-billets are heated to ductility temperature, pierced in helical rolling mill at 400 and 350 mm diameter mandrels to 600xvn.415x3200-3350 mm and 600x365x2800-2950 mm sleeves with rolling-outs µ=1.56 and µ=1.37. Said sleeves are rolled to commercial pipes at PRM 8-16" with rolling-outs µ=5.52 to µ=3.04 and diameter reduction of 29.0%. Pipes ate heat treated, etched and subjected to ultrasound control and acceptance with pipe diameter tolerance of +1.25/-1.0% and wall thickness tolerance of +20/-5.0%.

EFFECT: higher pipe surface quality and Pilger mill efficiency.

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Description

The invention relates to pipe rolling production, and in particular to a method for the production of seamless pipes with a size of 426 × 21-40 mm for steam boilers, steam pipelines and collectors of plants with high and supercritical parameters of steam from hollow ingots-blanks of electroslag remelting steel grade 10X9MFB-Sh and can be used on an 8-16 ”pipe-rolling installation with pilgrim mills in the production of commodity pipes measuring 426 × 21-40 mm.

In the practice of pipe-rolling production, there is a method of manufacturing boiler pipes of large and medium diameters from forged billets of steels of grades 20, 15GS, 15KhM, 12Kh1MF, 15Kh1M1F, 12Kh2MFSR, 10Kh9MFB, 12Kh11 V2MF, 08Kh16N9M2, 12Kh18N12T and 10Kh13G12B2K2 with specific properties that include , forging them into forgings (compaction of the structure) with a yoke of ≥2.5, machining the forgings into billets (turning with metal removal of 10-15 mm per side), drilling in the blanks of a central hole with a diameter of 100 ± 5 mm to remove the central of IVc porosity and nonmetallic inclusions, heating the workpieces to a plasticity temperature, piercing the workpieces in a cross-helical rolling mill into sleeves, rolling the sleeves into tubes with a diameter of 245-550 mm on an 8-16 ”pilgrim installation with a diameter tolerance of + 1.25 / -1 , 0 and wall thickness + 25 / -5% (TU 14-1-2560-78 "Forged pipe billet for boiler pipes", TU 14-3-460-2003 and TU 14-3R-55-2001 "Seamless steel pipes for steam boilers and pipelines "and TU 14-3-420-75" Pipes for steam boilers and pipelines from steel 15GS and 15Kh1M1F ").

The disadvantage of this method is the high energy intensity of the process associated with heating and deformation (forging) of the ingots into forgings, followed by turning and drilling of the central hole, heating the workpieces to a plasticity temperature, piercing and rolling them into pipes on pilgrim mills with a wall tolerance of + 20 / - 5%, increased consumption coefficient of the metal during the redistribution of the ingot - forgings - billets - pipes and, as a result, the high cost of pipes, as well as the fact that this steel grade is included in TU14-3R-55-2001, but pipes from it are up to infusion no time has been produced.

In pipe production, there is a known method for manufacturing large diameter gas lift pipes from 09G2S steel ingots for the production of ESR and VDP (Patent RU No. 2119395, class B21B 19/04), where the deformation of the ingots in the piercing mill is carried out along the crystals, setting the ingots in the mill with the head part, and stitched with a posad in diameter by the amount

, $$D=2S_G\left(\mathrm{one}-\sin \alpha \right)/S_C$$

,

where S _G - wall thickness of the sleeve, mm;

S _C - wall thickness of the drilled ingot ESR, mm;

α is the angle of inclination of the crystallization front to the axis of the ingot, deg.

The disadvantage of this method of manufacturing large diameter pipes from ingots of ESR and VDP steel grade 09G2S is the need to manufacture macro templates to determine the angle of inclination of the crystallization front to the axis of the ingot, and the piercing of the ingots with shrink (head) part forward leads to the formation of defects in the form of internal captures at the front ends of the sleeves .

In pipe production, there is also known a method for the production of large diameter boiler pipes from ESR ingots (patent RU No. 2180874, class B21B 19/04), which reduces energy costs, reduces metal consumption and, as a result, reduces the cost of boiler pipes through the use of large diameter ingots and conducting the firmware process with a posad in diameter equal to 8-16%.

The disadvantages of this method are that, due to the low power of the drive of the piercing mill of ChTPZ OJSC, it is not possible to flash ESR steel of the 10Kh9MFB-Sh grade with a diameter of 8–16% by seeding.

In pipe production, there is also a known method for the production of hot-rolled conversion and commodity pipes of large and medium diameters from hard-to-deform grades of steel and alloys in tube rolling units with pilgrim mills (patent RU No. 2278750, class B21B 21/00), including turning of ESR ingots and forged billets, drilling a central hole with a diameter of 100 ± 5 mm, heating them to a temperature of plasticity, piercing with subsequent rolling in a cross-helical mill into sleeves and rolling the sleeves in a pilgrim mill into hot-rolled front pipes or pipes with a relatively thick wall, the first piercing of ESR ingots and forged billets in a cross-helical rolling mill is carried out with the bottom end forward, and the second piercing is carried out with shrink end forward, the pipes are rolled on a pilgrim mill with diameter to the wall thickness D / S = 6.5-8.0 with a hood µ≤4.5.

The disadvantage of this method is that it includes heating the ESR ingots and billets to a temperature of ductility, flashing them in a cross-helical rolling mill into billet sleeves, re-heating the billet blanks from a cold or hot seat to a ductility temperature, and flashing - rolling in the mill cross-helical rolling into sleeves with their subsequent rolling in a pilgrim mill to commodity or conversion pipes. Double heating leads to double burning of the metal, and the flashing of ESR ingots and billets into blanks, followed by rolling them into sleeves leads to a 2-fold loss in the performance of the pilgrim installation, and, consequently, to an increase in the cost of commodity and conversion pipes. This method extends to the production of seamless hot-deformed conversion and commodity pipes of large and medium diameters in tube-rolling plants with pilgrim mills from hard-to-deform grades of steel and alloys and does not provide for the production of boiler tubes from solid and hollow ingots of 10-H9MFB-Sh steel ESH.

The closest technical solution is a method for the production of seamless hot-deformed pipes of large and medium diameters on tube rolling plants with pilgrim mills for steam boilers, steam pipelines and collectors of plants with high and critical parameters of steam from electroslag remelting ingots and continuously cast billets (patent RU No. 232322314, class . В21В 19/04), which provides for the piercing of ESHP and NLZ ingots in cross-helical rolling mills with a diameter pitch depending on the grade of steel and the total hood When redistribution: ingot electroslag remelting - pipe or continuous cast billet - tube, wherein the values posad diameter ingots electroslag remelting in piercing in mills helical rolling determined from the expression Δ _ieshp = k _ieshp μ _i Σ, where Δ _ieshp - values of diameter spacing when flashing in the oblique rolling mills of ESR ingots of the i- th steel grade,%; µ _i Σ = µ _ave. µ _p - total drawing coefficient when rolling pipes of the i- th size; k _iashp is a coefficient taking into account the size of the span in diameter when flashing sleeves from ESR ingots of the i- th steel grade,%; µ _CR - the coefficient of extraction when piercing sleeves for rolling pipes of the i- th size; µ _p - drawing coefficient when rolling pipes of the i-th size on a pilgrim mill; the coefficients k _iashp for different steel grades vary from 24 to 40.

The disadvantage of this method is that it is very difficult to manufacture, because each pipe size requires its own ESR ingots, this method extends to the production of seamless hot-deformed pipes of large and medium diameters in tube rolling plants with pilgrim mills made of carbon steel grades and does not provide production of boiler tubes from EShP ingots of steel grade 10X9MFB-Sh.

Boiler pipes with a diameter of 426 mm with different wall thicknesses in Russia can only be produced on TPU 8-16 ”with pilgrim mills and on the HPT 450 mill.

The objective of the proposed method (invention) is the development of the production of seamless pipes with a size of 426x21-40 mm for steam boilers, steam pipelines and manifolds of installations with high and supercritical steam parameters from hollow ingots-blanks of electroslag remelting with dimensions 600хвн.240 × 2100 ± 50 and 600хвн.200 × 2100 ± 50 mm from steel grade 10X9MFB-Sh.

The technical result is achieved by the fact that in the known method for the production of seamless pipes with a size of 426 × 21-40 mm for steam boilers, steam pipelines and manifolds of installations with high and supercritical parameters of steam from steel grade 10X9MFB-Sh, including ingots melting by electroslag remelting, boring and turning hollow ingots into ingot blanks of size 600 × ext. 240 × 2100 ± 50 mm and 600хvn.200х2100 ± 50 mm, heating ingot blanks to a temperature of 1170-1180 ^о С, piercing them in a cross-helical rolling mill on mandrels with a diameter of 400 mm and 350 mm in sleeve size 6 00hvn. 415x3200-3350 mm and 600hvn. 365x2800-2959 mm with hoods µ = 1.56 and µ = 1.37, rolling of sleeves on TPU 8-16 ^'' with pilgrim mills into commodity pipes 426x15200-16000 - 426x40x9200-9800 mm with hoods from µ = 5.52 to µ = 3.67 and compression in diameter of 29.0%, heat treatment, pickling, straightening, ultrasonic inspection and pipe acceptance with a diameter tolerance of + 1.25 / -1.0% and wall thickness + 20 / -5.0%, hollow ingots of electroslag remelting are cast with a ratio of diameter to wall thickness D / S = 3.0-3.3, bored and turned into hollow ingots with a ratio of diameter to wall thickness corresponding to D / S = 3.0-3.7 and D / S = 2.8-3.1, large values of which refer to hollow ingots and ingots-blanks for rolling commodity pipes with smaller wall thicknesses, hollow ingots-blanks are heated in a methodical furnace according to the technology: ingots-blanks are planted on the furnace grates in batches of 6-8 pieces in a row with an interval of 1.0-1.25 hours at a temperature in the third zone of the furnace of 1000-1050 ° C; aging ingots-blanks on grates without tilting for 1.0-1.25 hours; heating ingots-billets with a diameter up to a temperature of 1170-1190 ° С at a speed of 1.9-2.1 ° С per minute for 5.5-6.0 hours with a uniform pitching in 20-23 minutes at an angle of 230-250 °; exposure at a temperature of 1170-1190 ° C for 0.5-0.75 hours with uniform tilting from the 6th to the 4th window after 15-20 minutes at an angle of 230-250 °; tilting from the 4th window to the furnace pit and delivery of ingot blanks from the furnace with a center temperature of ingot blanks of 1170-1190 ° C.

Comparative analysis with the prototype shows that the inventive method for the production of seamless pipes of 426 × 21-40 mm in size for steam boilers, steam pipelines and manifolds of installations with high and supercritical parameters of steam from 10Kh9MFB-Sh steel is distinguished by the fact that they produce electroslag remelting of hollow ingots, boring and turning of hollow ingots into ingots-billets with dimensions 600хвн.240 × 2100 ± 50 mm and 600хвн.200х2100 ± 50 mm, heating of ingots-blanks to a temperature of 1170-1180 ^о С, their piercing in a cross-helical rolling mill on diameters trom 400 mm and 350 mm into sleeves of size 600hvn. 415x3200-3350 mm and 600hvn. 365x2800-2959 mm with hoods µ = 1,56 and µ = 1,37, rolling of sleeves on TPU 8-16 ^'' with pilgrim mills in commodity pipes with a size of 426x21x15200-16000 - 426x40x9200-9800 mm with hoods from µ = 5.52 to µ = 3.67 and compression by diameter of 29.0%, heat treatment, etching, straightening, ultrasonic inspection and acceptance of pipes with a diameter tolerance of + 1.25 / -1.0% and wall thickness + 20 / -5.0%, hollow ingots of electroslag remelting are cast with a ratio of diameter to wall thickness D / S = 3.0-3.3, are bored and turned into hollow ingots -working with the ratio q diameter to wall thickness, respectively, D / S = 3.0-3.7 and D / S = 2.8-3.1, large values of which refer to hollow ingots and ingot blanks for rolling commodity pipes with smaller wall thicknesses hollow ingots-blanks are heated in a methodical furnace according to the technology: the ingots-blanks are planted on the furnace grates in batches of 6-8 pieces in a row with an interval of 1.0-1.25 hours at a temperature in the third zone of the furnace 1000-1050 ° FROM; aging ingots-blanks on grates without tilting for 1.0-1.25 hours; heating ingots-billets with a diameter up to a temperature of 1170-1190 ° С at a speed of 1.9-2.1 ° С per minute for 5.5-6.0 hours with a uniform pitching in 20-23 minutes at an angle of 230-250 °; exposure at a temperature of 1170-1190 ° C for 0.5-0.75 hours with uniform tilting from the 6th to the 4th window after 15-20 minutes at an angle of 230-250 °; tilting from the 4th window to the furnace pit and delivery of ingot blanks from the furnace with a center temperature of ingot blanks of 1170-1190 ° C. Thus, these differences allow us to conclude that the criterion of "inventive step".

 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 the patentability "inventive step".

The proposed method for the production of seamless pipes with a size of 426 × 21-40 mm for steam boilers, steam pipelines and manifolds of plants with high and supercritical parameters of steam from 10Kh9MFB-Sh steel was carried out on TPU 8-16 ”with pilgrim mills when rolling 426x35 mm pipes from hollow ingots ESH blanks measuring 600x2100 ± 50 mm.

For comparison, this pipe size was rolled according to the classical scheme, i.e. from ingot blanks measuring 565 × 100 × 1750 ± 50 mm. Data on the rolling of pig tubes 465 × 35 mm in size from ESHB ingots (existing technology) and ESH hollow ingots (proposed technology) from 10Kh9MFB-Sh steel to TPU 8-16 ”with pilgrim mills and are shown in table 1. From table 1. 1 it can be seen that the production of commodity pipes with a size of 465 × 35 mm according to the proposed technology was made from hollow ingots - ESR blanks with a size of 600xvn.200 × 2100 ± 50 mm. Five hollow ingots - ESR blanks with a total weight of 22.805 tons, which were heated in a methodical furnace to a temperature of 1170-1185 ° C and stitched - rolled in a cross-section mill, size to outer diameter on a mandrel with a diameter of 375 mm in sleeve sizes 600xvn. 390x3050-3200 mm with hoods µ = 1.49. The sleeves are rolled on a pilgrim mill in commodity pipes measuring 426 × 35 × 8900-9400 mm with a hood µ = 3.57 and a compression in diameter Δ = 29.0%. Commodity pipes were rolled on a pilgrim mill in rolls with a diameter of 434 mm caliber with feeds of sleeves into the deformation zone 23-25 mm. Technological waste was cut off from the pipes on a hot cutting saw, then the pipes were heat treated, pickled, repaired (if necessary), passed ultrasonic testing and adopted in accordance with TU 14-3R-55-2001 with a diameter tolerance of + 1.25 / - 1.0% wall thickness + 20 / -5%. It was adopted 5 pipes with a size of 426 × 35 × 8900-9400 mm with a total weight of 16.520 tons. The expenditure coefficient of the metal in the pipes of this batch was 1.269. For comparison, 5 ESR ingots-blanks with a size of 585 × 100 × 1750 ± 50 mm with a total mass of 16.695 tons, which were heated to a plasticity temperature, were sewn on a mandrel with a diameter of 275 mm with hoods µ = 1.2 and a rise in diameter δ = 2.7% in sleeves - blanks measuring 580хвн.290х2040-2160 mm. The billet sleeves from a cold embankment were heated in a methodical furnace to a temperature of ductility, stitched-rolled on a mandrel with a diameter of 375 mm with hoods µ = 1.09 and a diameter rise of δ = 3.45 into sleeves of 600hvn size 2220-2350mm in diameter. Sleeves are rolled on a pilgrim mill in commodity pipes measuring 426 × 35 mm. In accordance with TU 14-3R-55-2001, 5 pipes with a total mass of 11.097 tons were accepted. The expenditure coefficient of metal for pipes of this batch was 1.505. When rolling pipes of this size according to the proposed technology, a decrease in the expenditure coefficient of the metal by 236 kg for each ton of commodity pipes was obtained.

Thus, the use of the proposed method will allow for the first time in Russia to produce seamless pipes with a size of 426 × 21-40 mm from hollow - 10Kh9MFB-Sh steel ESR ingots for steam boilers, steam pipelines and collectors of plants with high and supercritical steam parameters, which will reduce energy costs by excluding from the technological process the firmware of ingots-blanks into blanks-blanks, to produce high-quality commodity and conversion pipes at TPU8-16 ”with pilgrim mills of ChTPZ OJSC, to reduce metal consumption, ovysit performance TPU 8-16 "with pilger and hence reduce the cost of boiler tubes size 426h21-40 mm steel 10H9MFB-III.

The data on rolling commodity pipes of 426x35 mm in size made of 10Kh9MB-Sh steel on TPU 8-16 ”with pilgrim mills according to the existing and proposed technologies are given in the table.

Table 1

Type of technology Size of blanks and hollow
Ingot - ESR blanks
(mm) Weight of blanks and
ESW hollow ingots (kg) Flashing blanks and flashing - rolling cartridges Pilgrim mill rolling Metal consumption ratio The size of the sleeves blanks / size sleeves (mm) Mandrel Diameter (mm) Coeff. hoods (µ) Diameter rise or landing (δ or Δ)
(%) Pipe Size (mm) Coeff.
hoods (µ) Diameter compression (Δ,%) Mass delivered pipes (kg) Existing 565x100x1800 3434

$$\frac{\text{580}x\mathrm{at}n.290\times 2160}{600x\mathrm{at}n.390\times 2350}$$

$$\frac{275}{375}$$

$$\frac{1.20}{1.09}$$

$$\frac{2.7}{3.45}$$

- 3.57 Δ = 29.0 2298 426 × 30x6400 565x100x1750 3339 $$\frac{\text{580}x\mathrm{at}n.290\times 2160}{600x\mathrm{at}n.390\times 2350}$$

- 2262 426 × 35 × 6200 565x100x1775 3387 $$\frac{\text{580}x\mathrm{at}n.290\times 2160}{600x\mathrm{at}n.390\times 2350}$$

- 2262 426 × 35 × 6300 565x100x1700 3244 $$\frac{\text{580}x\mathrm{at}n.290\times 2160}{600x\mathrm{at}n.390\times 2350}$$

-
426 × 35 × 5900 2120 565x100x1725 3291 $$\frac{\text{580}x\mathrm{at}n.290\times 2160}{600x\mathrm{at}n.390\times 2350}$$

- 2191 426 × 35 × 6100 Total: 16695 - - - - - - - 11097 1,505 Proposed 600hvn × 200 × 2100 4141 600 × ext. 390 × 3130 375 1.49 0 426 × 35 × 9150 3.57 Δ = 29.0 3286 600hvn × 200 × 2150 4240 600 × ext. 390 × 3200 426 × 35 × 9400 3376 600hvn × 200 × 2150 4240 600 × ext. 390 × 3200 426 × 35 × 9400 3376 600hvn. × 200 × 2050 4663 600 × ext. 390 × 3050 426 × 35 × 89000 3196 600hvn × 200 × 2100 4141 600 × ext. 390 × 3130 426 × 35 × 9150 3286 Total: 20805 - - - - - - - 16520 1,269

Claims (3)

1. Method for the production of seamless pipes with a size of 426 × 21-40 mm for steam boilers, steam pipelines and manifolds of plants with high and supercritical parameters of steam from 10Kh9MFB-Sh steel, including electroslag remelting of hollow ingots, turning of hollow ingots into 600hvn ingots .240 × 2100 ± 50 mm and 600хвн.200х2100 ± 50 mm, heating the ingot blanks to a temperature of 1170-1180 ^о С, stitching them in a cross-screw rolling mill on mandrels with a diameter of 400 mm and 350 mm in sleeves 600хvn. 415х3200- 3350 mm and 600hvn. 365x2800-2959 mm with hoods µ = 1.56 and µ = 1.37, pr casing of sleeves on TPU 8-16 ^'' with pilgrim mills into commodity pipes of 426x15200-16000 - 426x40x9200-9800 mm in size with hoods from µ = 5.52 to µ = 3.67 and compression in diameter of 29.0%, heat treatment, etching, straightening, ultrasonic inspection and acceptance of pipes with a tolerance of + 1.25 / -1.0% in diameter and + 20 / -5.0% in wall thickness. 2. The method according to claim 1, characterized in that the hollow ingots of electroslag remelting are cast with a diameter to wall thickness ratio of D / S = 3.0-3.3, machined and bored into hollow ingots with a diameter to wall thickness ratio, D / S = 2.8-3.1, large values of which refer to hollow ingots and ingot blanks for rolling commodity pipes with smaller wall thicknesses. 3. The method according to claim 1, characterized in that the hollow ingots-billets are heated in a methodological furnace using the technology:
- ingots-blanks are planted on the furnace grates in batches of 6-8 pieces in a row with an interval of 1.0-1.25 hours at a temperature in the third zone of the furnace of 1000-1050 ° C;
- exposure of ingot blanks to grates without tilting for 1.0-1.25 hours;
- heating the ingot blanks to a temperature of 1170-1190 ° C at a speed of 1.9-2.1 ° C per minute for 5.5-6.0 hours with uniform pitching in 20-23 minutes at an angle of 230-250 °;
- exposure at a temperature of 1170-1190 ° C for 0.5-0.75 hours with uniform tilting from the 6th to the 4th window in 15-20 minutes at an angle of 230-250 °;
- tilting from the 4th window onto the pit of the furnace and delivery of ingot-billets from the furnace with the temperature of the center of the ingot-billet 1170-1190 ° C.