RU2537413C2 - PRODUCTION OF 273×9-60 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 - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to pipe rolling. ESR 470×100×1750±50 mm ingots are heated to 1200-1210°C and rolled at screw rolling mills to 500×ID365×2980-3150 mm sleeves at 350 mm diameter mandrel with rolling-out µ=1.75 lift in diameters of 6.3-6.5%. Sleeves are rolled to 377×22×8000-8500 mm pipes with rolling-out µ=3.74 diameter reduction of 24.6%. Pipes are heat treated and rolled at CPR 450 mill to 325×15×13200-14000, 325×16×12400-13200, 325×17×11700-12400 and 325×18×1100-11800 mm pipes with rolling-out µ=1.68, µ=1.58, µ=1.49 and µ=1.41. Said pipes cut to pipe lengths 325×15×6600-7000, 325×16×6200-6600 mm, 325×17×5850-6200 mm, 325×18×5500-5900 mm are rolled at CPR 450 mill to commercial pipes sized to 273×9×12600-13300 mm, 273×10×11300-12000 mm, 273×11×10300-1100, 273×12×9400-10100 and 273×13×8600-9300 mm with rolling-out µ=1.96, µ=1.88, µ=1.82, µ=1.76, and µ=1.64. Then, they are subjected to ultrasound control and acceptance with diameter and wall depth allowances of +1.0% and +15/-5%, respectively.

EFFECT: higher surface quality and precision.

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Description

The invention relates to pipe production, and in particular to a method for the production of seamless pipes of 273 × 9-13 mm in size for steam boilers, steam pipelines and manifolds of plants with high and supercritical parameters of steam from bar stocks of electroslag remelting steel grade 10X9MFB-Sh, and can be used on pipe rolling plants with pilgrim mills in the manufacture of redistribution pipes 377 × 22 and 325 × 20 mm in size for their subsequent rolling into commodity pipes of 273 × 9-11 and 273 × 12-13 mm in size at the KhPT 450 mill.

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 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 with a diameter tolerance of + 1.25 / -1 , 0 and wall thickness + 20 / -5% (TU 14-1-2560-78 “Forged pipe billets 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 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 - forging - billet - pipe and, as a consequence, the high cost of pipes, as well as the fact that this steel grade, although it is included in TU14-3R-55-2001, but pipes to the last m No items were made from it.

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 ingots are deformed in the piercing mill along the location of the crystals, setting the ingots in the transverse helical mill rolling the head part, and flashing with a seam in diameter by the amount

D = 2S _G (1-sinα) / 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 a known 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 is that, due to the low power of the drive of the transverse-screw firmware mill of ChTPZ OJSC, ESR ingots from this brand began to flash with a pitch of 8-16% in diameter, it is not possible.

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 parameters of steam from electroslag remelting ingots and continuously cast billets (Patent RU No. 2322314, cl . 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 ingot ingot - a pipe or a continuously cast billet - a pipe, while the values of the pitch values according to the diameter of electroslag ingot ingots when piercing in cross-helical rolling mills are determined from the expression

Δ _i′ashp = k _i′eshp µ _i Σ,

where Δ _i′eshp are the values of the sizes according to diameter when piercing in the helical rolling mills of ESR ingots of i-steel grade,%;

µ _i Σ = µ _nр µ _n - total drawing coefficient when rolling pipes of the i-th size;

k _i'eshp - coefficient taking into account the size of the gang in diameter when flashing sleeves from ESR ingots of i-steel grade,%;

µ _nр — drawing coefficient for flashing sleeves for rolling pipes of the i-th size;

µ _n is the drawing coefficient when rolling j-size pipes on a pilgrim mill, while the coefficients k _i′shp for different grades vary from 24 to 40.

The disadvantage of this method is that it is very difficult to manufacture, since each pipe size requires its own ESR ingot sizes, this method extends to the production of seamless hot-deformed pipes of large and medium diameters in tube rolling plants with pilgrim mills and does not provide for the production of boiler pipes from EShP ingots of steel grade 10X9MFB-Sh. Currently, Russian factories, namely ZMZ OJSC and Mechel OJSC, have mastered the production of ESR ingots of 430 × 1750 ± 50, 470 × 1750 ± 50, 490 × 1750 ± 50, 565 × 1750 ± 50 and 620 × sizes 1750 ± 50 mm. For the production of other diameters, molds are needed, the production of which requires large investments, and there is no reason to, because the geometric dimensions of the molds can be unified.

This pipe size can be produced on TPU 350 with an automatic mill, but these installations are not available in Russia.

Rolling pipes with a size of 273 × 9-13 mm in medium pipe rolling plants with pilgrim mills is problematic due to the low temperature of 10Kh9MFB-Sh steel under a deformation of 1180-1200 ° C. From ESR ingots of 490 × 100 × 1750 ± 50 mm in size on a pilgrim mill, a pipe of 273 × 9 mm up to 36 meters long is obtained. The rolling time of such a pipe is more than 4.5 minutes. During this period of time, the sleeve tube cools down to 800 ° C (at a recommended minimum of 850 ° C at the end of rolling). Pipe rolling and rolling of pilgrim heads made of 10Kh9MFB-Sh steel at temperatures below 850 ° C leads to increased loads on the drive of the pilgrim mill and tightening the mandrels, which, in turn, can lead to breakage of the safety bolts and spindles of the pilgrim mill and lower productivity expense of removing mandrels due to puffs. Rolling pipes with a size of 273 × 9-13 mm in tube rolling plants with pilgrim mills with a tolerance of wall thickness of + 20 / -5% leads to additional metal consumption.

The objective of the proposed method (invention) is the development of the production of seamless pipes with a size of 273 × 9-13 mm for steam boilers, steam pipelines and manifolds of installations with high and supercritical parameters of steam from electroslag remelting ingots with a size of 470 × 100 × 1750 ± 50 mm of 10Kh9MFB-Sh steel instead of forged billets in the conditions of ChTPZ OJSC, namely the production of 325 × 16 and 377 × 22 mm conversion pipes at 8-16 ”TPU with pilgrim mills and subsequent conversion (rolling) of conversion pipes at the KhPT 450 mill into 273 freight pipes × 9-13 m with increased requirements for mechanical properties, geometric dimensions and surface quality of pipes, reducing metal consumption during redistribution of ESR ingot - boiler pipe by reducing the positive tolerance on wall thickness and increasing the mechanical properties of pipe metal, due to the fractional deformation during rolling at TPU with pilgrim mills and rolling (rolling) of conversion pipes at the HPT mills.

The technical result is achieved by the fact that in the known method for the production of seamless pipes 273 × 9-13 mm in size for steam boilers, steam pipelines and manifolds of installations with high and supercritical parameters of steam from electroslag remelting ingots of 10Kh9MFB-Sh steel, including melting ingots-billets by electroslag remelting size 470 × 100 × 1750 ± 50 mm, heating ingots to a temperature of 1200-1210 ° C, piercing in helical rolling mills in sleeves of size 500 × ext. 365 × 2980-3150 mm on a mandrel with a diameter of 350 mm with hood µ = 1.75 and rise diameter 6.3–6.5%, rolling of sleeves on TPU with pilgrim mills into redistribution pipes 377 × 22 × 8000-8500 mm in size with a hood µ = 3.74 and diameter reduction of 24.6%, heat treatment and rolling conversion pipes of 377 × 22 × 8000-8500 mm in size at the KhTT 450 mill into conversion pipes of 325 × 15 × 13200-14000, 325 × 16 × 12400-13200, 325 × 17 × 117000-12400 and 325 × 18 × 11000-11800 mm with hoods, respectively, µ = 1.68, µ = 1.58, µ = 1.49 and µ = 1.41, heat treatment of cold rolled steel tubes, cutting into equal length slabs, rolling of steel tubes 325 × 15 × 6600 -7000 mm at the HPT 450 mill into commodity pipes measuring 273 × 9 × 12600- 13300 mm, rolling of conversion pipes 325 × 16 × 6200-6600 mm in size to commodity pipes of 273 × 10 × 11300-12000 mm, rolling of conversion pipes of 325 × 17 × 5850-6200 mm into commodity pipes of 273 × 11 × 10300- 11000 mm and rolling conversion pipes 325 × 18 × 5500-5900 mm in size into commodity pipes 273 × 12 × 9400-10100 mm and 273 × 13 × 8600-9300 mm with hoods, respectively, µ = 1.96, µ = 1.88 , µ = 1.82, µ = 1.76 and µ = 1.64, heat treatment, pickling, straightening, ultrasonic testing and pipe acceptance with a tolerance of ± 1.0% in diameter and + 15 / -5% wall thickness.

Comparative analysis with the prototype shows that the inventive method for the production of seamless pipes 273 × 9-13 mm in size for steam boilers, steam pipelines and manifolds of plants with high and supercritical parameters of steam from electroslag remelting ingots of 10Kh9MFB-Sh steel is characterized in that they produce ingots - billets by electroslag remelting with a size of 470 × 100 × 1750 ± 50 mm, heating ingots-billets to a temperature of 1200-1210 ° C, piercing in cross-screw mills in sleeves of size 500 × ext. 365 × 2980-3150 mm on a mandrel diameter m 350 mm with a hood µ = 1.75 and a rise in diameter of 6.3-6.5%, rolling of sleeves on a TPU with pilgrim mills into conversion pipes of 377 × 22 × 8000-8500 mm with a hood µ = 3.74 and compression by diameter of 24.6%, heat treatment and rolling of conversion pipes of size 377 × 22 × 8000-8500 mm at the KhPT 450 mill into conversion pipes of 325 × 15 × 13200-14000, 325 × 16 × 12400-13200, 325 × 17 × 117000-12400 and 325 × 18 × 11000-11800 mm with hoods, respectively, µ = 1.68, µ = 1.58, µ = 1.49 and µ = 1.41, heat treatment of cold rolled pipes, cutting into pipe-equal lengths, rolling of conversion tubes 325 × 15 × 6600-7000 mm in size at the KhPT 450 mill in pipes of size 273 × 9 × 12,600–13,300 mm, rolling of conversion pipes 325 × 16 × 6,200–6,600 mm into commodity pipes of 273 × 10 × 11,300–12,000 mm, rolling of conversion pipes 325 × 17 × 5850-6200 mm in commodity pipes 273 × 11 × 10,300–11,000 mm in size and rolling of conversion pipes 325 × 18 × 5500-5900 mm into commodity pipes of 273 × 12 × 9400-10100 mm and 273 × 13 × 8600-9300 mm with hoods, respectively µ = 1.96, µ = 1.88, µ = 1.82, µ = 1.76 and µ = 1.64, heat treatment, pickling, straightening, ultrasonic inspection and pipe acceptance with a diameter tolerance of ± 1.0% and wall thickness + 15 / -5%. Thus, these differences allow us to conclude that the criterion of “inventive step” is met.

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”.

Conveyor pipes 377 × 22 mm in size were rolled from 10Kh9MFB-Sh steel at 8-16 ”TPU with pilgrim mills from EShP ingots 470 × 100 × 1750 ± 50 mm in size, and the section pipes were 377 × 22 mm in size and 325 × 16 mm and their subsequent rolling into goods 273 × 10 mm in size were made at the KhPT 450 mill of ChTPZ OJSC. Data on rolling of conversion pipes 377 × 22 mm in size from 10Kh9MFB-Sh steel at 8-16 ”TPU with pilgrim mills and rolling of conversion pipes 377 × 22 mm into commodity pipes of 273 × 10 mm at KhPT 250 mill of ChTPZ OJSC , the results of delivery, mechanical properties and geometric dimensions of the pipes are given in tables 1 and 2. 5 ESR ingots of 470 × 100 × 1700-1750 mm in size were delivered to production, delivered by Mechel OAO. ESR ingots were rolled at 8-16 ”TPU into conversion pipes 377 × 22 × 8100-8400 mm in size. Ingots for rolling pig tubes were planted in a methodical furnace and heated to a temperature of 1200-1210 ° C. Ingots with a total mass of 11.174 tons were stitched in a cross-rolling mill on a mandrel with a diameter of 350 mm into sleeves measuring 460 × ext. 365 × 2980-3060 mm with a hood µ = 1.75 and a diameter overburden of 2.1%. Then the sleeves were rolled at 8-16 ”TPU with pilgrim mills into redistribution pipes 377 × 22 × 8100-8400 mm in size with a hood µ = 3.74 and a diameter reduction Δ = 24.6%. Converted hot-rolled pipes were sent to workshop No. 5 for cold processing. In workshop No. 5, hot-rolled steel tubes 377 × 22 mm in size were rolled at the KhPT 450 mill to cold-rolled steel tubes of 325 × 16 × 12900-13500 mm in size. The pipes were cut into two equal parts and rolled into commodity pipes measuring 273 × 10 × 10900-11400 mm. As a result, ten pipes 273 × 10 × 10900-11400 mm in total weight of 7.559 tons were rolled and made in accordance with TU 14-ЗР-55-2001. The average expenditure coefficient of the metal for this batch of pipes amounted to 1,478. Comparisons on this rolling were not made since Pipes of this range from 10Kh9MFB-Sh steel in Russia were not produced 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. The table shows 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 / -5.0%. And since the quality of the metal of the ESR ingots is much better, the main criterion for boiler pipes, long-term strength, will be much higher.

Thus, the use of the proposed method will allow for the first time in Russia to produce seamless pipes with a size of 273 × 9-13 mm directly from ESR ingots for steam boilers, steam pipelines and manifolds of plants with high and supercritical steam parameters with mechanical properties of the metal and geometric dimensions exceeding the data values the indicators given in TU 14-3R-55-2001, which will significantly reduce energy costs by eliminating the heating of ingots for forging and forging of ingots into forgings, and reduce the load and when flashing ingot-blanks of ESR with differentiated compressions in diameter and producing high-quality conversion pipes at TPU8-16 "with pilgrim mills of OAO" ChTPZ "for the subsequent conversion of conversion pipes into commodity pipes at KhPT 450 mills in accordance with customer orders, reduce the metal consumption rate during the redistribution of the ingot - the preparation of the ESR - the boiler pipe, and, therefore, reduce the cost of boiler pipes from this steel grade.

Claims (1)

Method for the production of seamless pipes 273 × 9-13 mm in size for steam boilers, steam pipelines and collectors of installations with high and supercritical parameters of steam from electroslag remelting ingots of 10Kh9MFB-Sh steel, including smelting of ingot billets by electroslag remelting of 470 × 100 × 1750 ± 50 mm, heating of ingot blanks to a temperature of 1200-1210 ° C, piercing in cross-screw mills in sleeves of size 500 × ext. 365 × 2980-3150 mm on a mandrel with a diameter of 350 mm with a hood µ = 1.75 and a rise in diameter 6.3-6.5%, rolling of sleeves on TPU with pilgrims with mills into conversion pipes 377 × 22 × 8000-8500 mm in size with a hood µ = 3.74 and compression in diameter of 24.6%, heat treatment and rolling of conversion pipes in the size 377 × 22 × 8000-8500 mm at the KhPT 450 mill into conversion 325 × 15 × 13200-14000, 325 × 16 × 12400-13200, 325 × 17 × 11700-12400 and 325 × 18 × 1100-11800 mm pipes with hoods, respectively, µ = 1.68, µ = 1.58, µ = 1.49 and µ = 1.41, heat treatment of cold-rolled steel tubes, cutting into equal length pipes, rolling of steel tubes 325 × 15 × 6600-7000 mm in size at the KhPT 450 mill into commodity pipes 273 × 9 × 12600- 13,300 mm, rolling of conversion tubes 325 × 16 × 6200-6600 in size pipelines measuring 273 × 10 × 11,300-12,000 mm, rolling conversion tubes 325 × 17 × 5850-6200 mm into commodity pipes 273 × 11 × 10300-1100 and rolling conversion tubes 325 × 18 × 5500-5900 mm into commodity pipes 273 × 12 × 9400-10100 and 273 × 13 × 8600-9300 mm in size with hoods, respectively, µ = 1.96, µ = 1.88, µ = 1.82, µ = 1.76, and µ = 1, 64, heat treatment, etching, dressing, ultrasonic inspection and acceptance of pipes with a tolerance of + 1.0% in diameter and + 15 / -5% in wall thickness.