RU2527580C2 - PRODUCTION OF 245×10-15 mm SEAMLESS HOT-ROLLED PIPES FOR STEAM BOILERS, STEAM PIPELINES AND MANIFOLDS OF PLANTS WITH HIGH AND SUPERHIGH STEAM PARAMETERS FROM ESR INGOTS OF "10Х9МБФ-Ш"-GRADE STEEL - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention aims at decreasing the costs of 245x10-15 mm seamless hot-rolled pipes for steam boilers, steam pipelines and manifolds of plants with high and superhigh steam parameters from ESR ingots of "10Х9МФБ-Ш"-grade steel. Pipes are made from ESR ingots-billets. Decreased metal input and quantity of equipment faults result from application of 430×100×1750±50 mm-ingots to be heated to 1180-1190°C, rolled at helical rolling machine to sleeves sized to 460xID.265×2060-2180 mm at 250 mm diameter mandrel with rolling-out µ=1.21 and diameter reduction of 6.9-7.1%. Said ingots-billets are heated to ductility temperature and rolled at Pilger mill on taper mandrels to rerolled hot-rolled pipes sized to 273×16×14200-15200 and 273×19×11600-12500 mm at feed m=16-18 mm, with rolling-out µ=8.60 and µ=7. 32 and diameter reduction δ=40.7% Pipes are cut to equal-size lengths Pipes are turned, bored and rolled at mill CPR 250 to commercial pipes sized to 245×10×12100-1300, 245×11×11000-11800 mm and 245×12×10100-10800 mm with rolling-out µ=1.75, µ=1.60 and µ=1.47. Pipes sized to 273×19×5800-6250 mm are rolled at CPR 250 mills to commercial pipes sized to 245×13×8500-9300, 245×14×8000-8600 and 245×15×7800-8400 mm with rolling-out µ=1.53, µ=1.43 and µ=1.40. Commercial pipes are cut to the order, heat treated, straightened and accepted with diameter allowance of ±1.0% wall allowance of +15/-5.0.

EFFECT: lower metal loses, decreased equipment faults.

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Description

The invention relates to pipe rolling production, and in particular to a method for the production of seamless pipes of 245 × 10-15 mm in size for steam boilers, steam pipelines and manifolds of plants with high and supercritical parameters of steam from electroslag remelting ingots of grade 10X9MFB-Sh steel and can be used on pipe rolling plants with pilgrim mills and at the HPT 250 mills in the production of boiler pipes.

In the practice of pipe production, there is a method of manufacturing boiler pipes of large and medium diameters from forged billets of steels of grades 20, 15GS, 15XM, 12X1MF, 15X1M1F, 12X2MFSR, 10X9MFB, 12X11V2MF, 08X16H9M2, 12X18N12T, 10Kh13G12B2K2 with mechanical 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 quasi-porosity and non-metallic inclusions, heating the workpieces to the ductility temperature, piercing the workpieces in cross-screw rolling mills into sleeves, rolling the sleeves into pipes with a diameter of 245-550 mm on an 8-16 ″ pilgrim installation, rolling the sleeves on pilgrim installations or automatic mills into pipes 219 mm in diameter with wall thicknesses from 8 to 50 mm (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 made of steel 15GS and 15X1M1F ″).

The disadvantages of this method are the high energy intensity of the process associated with heating and deformation (forging) of the ingots into forgings, and the increased expenditure coefficient of the metal when rolling thin-walled pipes from high-alloy steel grades on a pilgrim mill. Rolling pipes 245 × 10-15 mm in size from steel grade 10X9MFB in pipe rolling plants with pilgrim mills is hindered by a low deformation temperature, so the temperature of the sleeve during flashing should be no more than 1200 ° C. The tube rolling time of 245 × 10-15 mm on the pilgrim mill is more than 4 minutes. For a given period of time, the sleeve tube cools down to 800-820 ° C (at a recommended minimum of 850 ° C at the end of rolling). Rolling pipes at temperatures below 850 ° C leads to increased loads on the drive of the pilgrim mill and tightening mandrels, which in turn leads to increased metal losses and increases the likelihood of breakdown of the equipment of the pilgrim mill. To eliminate the tightening of the mandrels, pipe rolling is used using mandrels with an increased taper up to 4-8 mm instead of the existing taper of 1-2 mm, and this leads to a longitudinal difference and an increase in the rejection of pipes by wall thickness.

The closest technical solution is a method for the production of seamless hot-deformed pipes of large and medium diameters in tube rolling plants with pilgrim mills for steam boilers, steam pipelines and manifolds of plants with high and supercritical steam parameters from electroslag remelting ingots and continuously cast billets (patent RU No. 2322314, class . В21В 19/04), which provides for the piercing of ESR and NLZ ingots in cross-helical rolling mills with a diameter pitch depending on the grade of steel and the total output yields during redistribution of an electroslag remelting ingot - a pipe or a continuously cast billet - a pipe, while the values of spacing according to the diameter of electroslag ingots ingots when piercing in cross-helical rolling mills are determined from the expression Δ _i'ashp = k _i'ashp μ _i Σ where Δ _i'ashp - the values of the sizes according to diameter when piercing in the mills of cross-helical rolling of ESR ingots of i-steel grade,%; µ _i Σ = µ _pr µ _p - the total drawing coefficient when rolling pipes of the i-th size; k _i'ashp is a coefficient that takes into account the size of the chuck in diameter when flashing sleeves from ESR ingots of i-steel grade,%; µ _CR - the coefficient of extraction when piercing sleeves for rolling pipes of the i-th size; µ _p is the drawing coefficient when rolling j-size pipes on a pilgrim mill, while the coefficients k _i'ashp for different grades vary from 24 to 40.

The disadvantage of this method is that the firmware with a posad in diameter leads to increased loads on the drive of the piercing mill and increases the number of breakdowns.

The objective of the proposed method (invention) is the development of the production of seamless pipes 245 × 10-15 mm in size for steam boilers, steam pipelines and manifolds of plants with high and supercritical steam parameters from electroslag remelting ingots of 10Kh9MFB-Sh steel, reducing metal consumption and load on the piercing drive camp.

The technical result is achieved by the fact that in the known method for the production of seamless pipes with a size of 245 × 10-15 mm for steam boilers, steam pipelines and manifolds of plants with high and supercritical parameters of steam from electroslag remelting ingots (ESR) of steel grade 10X9MFB-Sh, the pipes are made from ingots - ESR blanks with a size of 430 × 100 × 1750 ± 50 mm, which are heated to a temperature of 1180-1190 ° C, are stitched in a cross-helical mill into sleeves of 460 × ext. 265 × 2060-2180 mm in diameter on a mandrel with a diameter of 250 mm with an extractor µ = 1.21 and a rise in diameter of 6.9-7.1%, gil We are rolling on TPU 8-16 ″ with pilgrim mills into conversion tubes of 273 × 16 × 14200-15200 and 273 × 19 × 11600-12500 mm in sizes with feeds m = 16-18 mm, with hoods µ = 8.60 and µ, respectively = 7.32 and compression in diameter δ = 40.7%, the pipes are cut into equal length pipes, pipes of 273 × 16 × 7100-7600 mm in size are rolled at the KhPT 250 mill into commodity pipes of 245 × 10 × 12100-13000 , 245 × 11 × 11000-11800 and 245 × 12 × 10100-10800 mm with hoods, respectively, µ = 1.75, µ = 1.60 and µ = 1.47, pipes measuring 273 × 19 × 5800-6250 mm are rolled onto KHPT 250 into commodity pipes 245 × 13 × 8500-9300, 245 × 14 × 8000-8600 and 245 × 15 × 7800-8400 mm in size with hoods µ = 1.53, µ = 1.43 and µ = 1.4 0, commodity pipes are cut into lengths in accordance with the order, heat treated, pickled, straightened and taken in diameter ± 1.0% and wall + 15.0 / -5.0%.

Comparative analysis with the prototype shows that pipes of 245 × 10-15 mm in size are produced from ESR ingots-blanks of 430 × 100 × 1750 ± 50 mm in size, which are heated to a temperature of 1180–1190 ° С, and are flashed into sleeves in a helical rolling mill 460 × in. 265 × 2060-2180 mm in size on a mandrel with a diameter of 250 mm with a hood µ = 1.21 and a rise in diameter of 6.9-7.1%, the sleeves are rolled on TPU 8-16 ″ with pilgrim mills into conversion pipes 273 × 16 × 14200-15200 and 273 × 19 × 11600-12500 mm in size with feeds m = 16-18 mm, with hoods µ = 8.60 and µ = 7.32, respectively, and diameter compression δ = 40.7% pipes cut n krat pipes of equal length, pipes measuring 273 × 16 × 7100-7600 mm are rolled at the KhPT 250 mill into commodity pipes of 245 × 10 × 12100-13000, 245 × 11 × 11000-11800 and 245 × 12 × 10100-10800 mm s with hoods, respectively, µ = 1.75, µ = 1.60 and µ = 1.47, pipes 273 × 19 × 5800-6250 mm in size are rolled at the KhPT 250 mill into commodity pipes 245 × 13 × 8500-9300, 245 × 14 × 8000-8600 and 245 × 15 × 7800-8400 mm with hoods µ = 1.53, µ = 1.43 and µ = 1.40, commodity pipes are cut into lengths in accordance with the order, heat treated, pickled, straightened and accepted in diameter ± 1.0% and wall + 15.0 / -5.0%. Thus, these differences allow us to conclude that the criterion is ″ 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 patentability ″ inventive step ″.

The method was carried out during rolling at TPU 8-16 ″ with pilgrim mills of conversion tubes 273 × 16 mm in size made of 10Kh9MFB-Sh steel for subsequent rolling on the KhPT 250 mill into commodity pipes 245 × 10 mm in size.

Data on rolling of conversion pipes 273 × 16 mm in size from steel grade 10X9MFB-Sh to TPU 8-16 ″ with pilgrim mills and rolling of conversion pipes in size 273 × 16 into commodity pipes measuring 245 × 10 mm at KhPT 250 mill of OAO ChTPZ, The results of the delivery, mechanical properties and geometric dimensions of the pipes are shown in Tables 1 and 2. 5 ESR ingots with a size of 430 × 100 × 1700-1750 mm delivered by Mechel OAO were set into production. Ingots for rolling pig tubes were planted in a methodical furnace and heated to a temperature of 1180-1190 ° C. Ingots with a total mass of 9.266 tons were stitched in a cross-helical mill on a mandrel of 250 mm into sleeves measuring 465 × ext. 265 × 2060-2120 mm with a hood of 1.21 and a rise in diameter of 7.0%. Then the sleeves were rolled on TPU 8-16 ″ with pilgrim mills into conversion tubes measuring 273 × 16 × 14200-14700 mm. Converted hot-rolled pipes were cut into two equal length pipes and sent to workshop No. 5 for cold processing. In workshop No. 5, hot-rolled chimneys measuring 273 × 16 mm in size were rolled at the KhPT 250 mill into cold-rolled commodity pipes of 245 × 10 mm in size. As a result, ten pipes 245 × 10 × 12000-12350 mm in total weight of 7.070 tons were rolled and made in accordance with TU 14-3R-55-2001. The average expenditure coefficient of the metal for this batch of pipes was 1.311. Comparisons on this rolling were not made since Pipes of this assortment from steel 10X9MFB-Sh were not produced in Russia due to the lack of technology and equipment for their production.

Table 2 shows data on the mechanical properties of the metal and the geometric dimensions of the pipes. From table 2 it is seen that the mechanical properties of the metal and the geometric dimensions of the tubes rolled from ESR ingots according to the proposed technology are higher than those of TU 14-3R-55-2001, which in turn gives a guaranteed opportunity to reduce the positive tolerance field for wall thickness and establish tolerance + 15 / -10% instead of the existing + 20 / -5%. And since the quality of the metal of the ESR ingots is much better, the main criterion for boiler pipes is the long-term strength will be much higher.

Thus, the use of the proposed method made it possible for the first time in Russia to produce seamless pipes with a size of 245 × 10-15 mm directly from ESR ingots for steam boilers, steam pipelines and collectors of installations with high and supercritical steam parameters with mechanical properties of the metal and geometric pipe sizes exceeding the values these indicators are given in TU 14-3R-55-2001, which will reduce energy consumption by eliminating the heating of ingots for forging and forging of ingots into forgings, to produce quality These conversion pipes at TPU 8-16 ″ with pilgrim mills of ChTPZ OJSC for their subsequent conversion into commodity ones in accordance with consumer orders.

Data on rolling of conversion pipes 273 × 16 mm in size from steel 10Kh9MFB-Sh to TPU 8-16 ″ with pilgrim mills and rolling conversion pipes in size 273 × 16 mm into commodity pipes of 245 × 10 mm in size at KhPT 250 mill of ChTPZ OJSC

Table 1 №№p / p ESR ingots size (mm) Ingot Weight (kg) Sleeve firmware Rolling commodity and conversion pipes on a pilgrim mill Rolling of conversion and commodity pipes at HPT 250 Consumption. coefficient metal Sleeve Size (mm) Mandrel Diameter (mm) Coeff. hoods (µ) Diameter rise or landing (δ or Δ) (%) Pipe Size (mm) Coeff. hoods (µ) Diameter compression (Δ,%) Size of limit tubes (mm) Coeff. retractors (µ) Size of delivered pipes (mm) Coeff. retractors (µ) Pipe Weight (kg) one 430 × 100 × 1700 1833 460 × 265 × 2060 273 × 16 × 14200 273 × 16 × 7100 245 × 10 × 12100 700.9 273 × 16 × 7100 245 × 10 × 12000 695.2 2 430 × 100 × 1725 1860 460 × 265 × 2090 273 × 16 × 14500 273 × 16 × 7250 245 × 10 × 12100 701.0 273 × 16 × 7250 245 × 10 × 12300 712.0 3 430 × 100 × 1750 1886 460 × 265 × 2120 250 1.21 δ = 7.0 273 × 16 × 14700 8.6 Δ = 41.7 273 × 16 × 7350 1,521 245 × 10 × 12400 1.75 718.3 273 × 16 × 7350 245 × 10 × 12550 727.0 four 430 × 100 × 1700 1833 460 × 265 × 2060 273 × 16 × 14200 273 × 16 × 7100 245 × 10 × 12000 695.2 273 × 16 × 7100 245 × 10 × 12050 698.1 5 430 × 100 × 1720 1854 460 × 265 × 2080 273 × 16 × 14400 273 × 16 × 7200 245 × 10 × 12200 706.7 273 × 16 × 7200 245 × 10 × 12350 715.4 Total: 9266 - - - - - - - - - - - 7069.3 1,311

Data on the mechanical properties of pipe metal at room temperature and geometric dimensions

Claims (1)

Method for the production of seamless pipes 245 × 10-15 mm in size for steam boilers, steam pipelines and manifolds of installations with high and supercritical parameters of steam from electroslag remelting ingots (ESH) of 10X9MFB-Sh steel, characterized in that the pipes are made from 430 × ESH ingots-blanks 100 × 1750 ± 50 mm, which are heated to a temperature of 1180-1190 ° C, are flashed in a cross-helical mill in sleeves of size 460hvn.265 × 2060-2180 mm on a mandrel with a diameter of 250 mm with a hood µ = 1.21 and a rise in a diameter of 6.9-7.1%, the sleeves are rolled on TPU 8-16 "with a pilgrim novyh mills in the conversion pipe size 273 × 16 × 14200-15200 and 273 × 19 × 11600-12500 mm with feeds m = 16-18 mm, with hoods, respectively, µ = 8.60 and µ = 7.32 and compression in diameter δ = 40.7%, the pipes are cut into slab pipes of equal length, while pipes of 273 × 16 × 7100-7600 mm in size are rolled on KPT 250 mills into commodity pipes of 245 × 10 × 12100-1300, 245 × 11 × 11000- 11800 mm and 245 × 12 × 10100-10800 mm with hoods, respectively, µ = 1.75, µ = 1.60 and µ = 1.47, and pipes with a size of 273 × 19 × 5800-6250 mm are rolled into commodity mills ХПТ 250 pipes 245 × 13 × 8500-9300, 245 × 14 × 8000-8600 and 245 × 15 × 7800-8400 mm in size with hoods µ = 1.53, µ = 1.43 and µ = 1.40, with commodity pipes loss is cut into lengths in accordance with the order, heat treated, etched, straightened and accepted with a tolerance of ± 1.0% in diameter and + 15 / -5.0 in wall.