Today's metallurgical production is inconceivable without the technology of continuous casting of steel and is due to the inherent savings in energy and time costs, increased productivity and quality of products, reductions in production costs, sales There is more effective investment. In connection with this, systematic maintenance of the continuous caster is carried out and, as a result, there will be an increase in the obligation of their replacement and repair. Evidence from metallurgical enterprises shows that the technical and technical-economic performance of continuous casting machines (CCMs) have a significant impact on the durability of rollers of supporting systems. The rollers of the assemblies, which are supported and expanded, operate at an important temperature regime of thermal cycling, the maximum temperature of the surface of the rollers can reach 650-750 °C. The rollers absorb the ferrostatic swelling and the liquid from the liquid. On straight plots, the rollers experience abrasive wear (Fig. 1). The wear of the working surface of the rollers is manifested by the wear of the surface ball and the formation of cracks and cracks. Apparently, the wear rate of the working surface material should not exceed 0.1-0.25 mm per 1 thousand. melts, with which the continuous caster can produce no less than 1 million tons of billets without changing rollers. It appears that electric arc fusion of the working surfaces of wear-resistant and corrosion-resistant steel rollers is the most effective and efficient way to improve the service life of such parts. This method of increasing the value of rollers is used by most companies that create continuous casting machines both in our country and there.
The enterprise "TM.WELTEK" solves this problem for metallurgical plants and repair enterprises by supplying a wide range of powder surfacing darts and know-how for welding technology (table). The bits are adapted to the processes of submerged arc fusion, CO 2 and Ar+CO 2 and open arc, and their characteristics are not compromised by foreign and domestic analogues.
Fig.1. Scheme of installation of continuous steel pouring.
Submerged welding
Submerged arc welding technologies are being implemented along a screw line with a single and split arc, without hammering and with transverse hammering, starting with a diameter of 70 mm or more. The technology of double-ball cladding has become the most widely used, and a number of repair services use triple-ball cladding. For this method of fusion, bits with a diameter of 2.0 to 4.0 mm are produced. Proposed powder darts allow you to fuse a ball of metal onto the working surface of the rollers that is resistant to wear and tear. The addition of powder dart with flux allows the removal of high-chromium (Cr-Mn-Ni-Mo-N, Cr-Mn-Ni-Mo-V-Nb) metal deposits with a plastic structure of low-carbon martensite, deposits with dispersed carbides and nitrides at min. Imizations instead of ferrite 5 -10% (Fig. 2).
Fig.2. Microstructure of deposited metal WELTEC-N470(×1000) (volume of δ-ferite portion 3.8%, hardness after deposition 42-46 HRC).
This plant was surrounded by a path of decline instead of coal.< 0,1% и частичной замены его азотом реализацией нами разработанного способа легирования азотом, оптимизации хрома и карбидообразующих элементов, а также параметров термического цикла наплавки. Наши порошковые проволоки адаптируется к различным вариантам технологии наплавки: количество наплавляемых слоев и марка основного металла роликов, выполнение наплавки с подслоем или без него с цель обеспечения требуемого химического состава и структурного состояния наплавленного металла. К преимуществам наплавки под флюсом можно отнести: высокую производительность, малый припуск на механическую обработку при соблюдении режимов и техники наплавки, отсутствие светового излучения и минимизация выделения дыма. Для наплавки высокохромистых сплавов рекомендуется применять флюсы марок АН26Н, АН20С. Недостатком этих флюсов является ухудшение отделимости шлаковой корки при температуре поверхности наплавляемого ролика более 300°С, что связано с высоким содержанием двуокиси кремния в составе флюсов. Состав шихты порошковой проволоки частично нейтрализует окислительную способность флюсов и достигается улучшение отделимости шлаковой корки (рис. 3). Наиболее предпочтительно применение нейтральных керамических флюсов, например, WAF325 (Welding Alloys), Record SK (Soudokay), OK 10.33, ОК 1061 (ESAB), которые обеспечивают самопроизвольное отделение шлаковой корки и более низкое содержание вредных примесей (S, P) в наплавленном металле (рис.3).
Fig.3. Surfacing of the continuous caster roller with Weltek-N470 powder dart and WAF325 flux.
Fusion of dry gas.
Suspension of deposits in dry gas is most effective in a mixture of 82Ar+18CO 2 or Ar mixed with carbon dioxide due to the greater stability of the process, reduced oxide content of the dry gas, change in base penetration. Before progress, it is possible to ensure a pleasant productivity of the process, visual control of the welding process, the chemical warehouse is designated by the composition of the dart and does not have the infusion characteristic of the flux, less water in the deposited metal is leveled with flux, It is simpler to implement the process with transverse cuttings. The welding process is characterized by good formability of the metal, easy water hardening of the slag pick and the ability to melt the ball without removing the slag. Some of the shortcomings include: the need to protect the blast and arc vibration, the less equal surface of the deposited metal, the need to cool down the exhaust gases, and the clogging of the dry gas supply nozzle. For this method of welding, bits with a diameter of 1.6 to 2.4 mm are produced both for applying the base ball and the balls of the working balls to the welded metal.
Fused with an open arc.
The process of open-arc fusion is superior to the power process in dry gas and is complemented by the need to dry out the dry gas, a more simplified configuration of the melting installation, and a greater source of energy. What a great achievement in the metallurgical aspect. With this method of welding, the possibility of forming metal deposited with nitrogen is realized. The need for such a metallurgical solution is due to the urgency of increasing the service life of continuous caster rollers due to the increase in the resistance of the deposited metal to disintegration and corrosion. The solution was most successfully implemented by the English company Welding Alloys. The working surface of the roller is subject to cyclic injection of high temperatures, which leads to a change in the structural state of the metal surface on the ball. The enlargement of grains and the formation of chromium carbides at their boundaries is avoided, which can lead to the development of intergranular corrosion. The consumption of the martensitic matrix with carbon leads to the formation of a soft ferrite ball, which has low resistance to mechanical wear. Replacing part of the carbon with nitrogen suppresses the process of enlargement of grains and the formation of chromium carbides between grains. The nitrides that are created are evenly distributed in the metal structure, and the effect of secondary reduction occurs during the thermal cycling process. The implementation of these mechanisms makes it possible to increase the resource of the videos. For this method of fusion, darts with a diameter of 20-24 mm are produced.
Powder particles from the TM.WELTEK enterprise for fusing caster rollers.
| Process | Drit | Diameter, mm | Zakhist |
| Submerged welding | Weltek-N470(C-Cr-Ni-Mo-V-Nb) 2 and 3 balls, HRC 40-45 Base steel: 15Х1МФУ. 25Х1М1Ф 16CrMo4(DIN10083) 21CrMoV511, 25CrM04 St52-3 (DIN10025) | 2,0—3,6 | AN20, AN26 WAF325 Record-SK OK10.33 OK 10.61 |
| Veltek-N470.01(Cr-Ni-Mo-V-Nb-N) 2 balls, HRC40-45 Base steel: 42CrMo4 (DIN10083) | 2,4—3,6 | ||
| Weltek-N470(C-Cr-Ni-Mo-V-Nb) 1 ball HRC40-45 Base steel: 42CrMo4 (DIN10083) Ball Weltek-N472(Cr-Mn) | |||
| Veltek-N470.02(C-Cr-Ni-Mo-V) 2 and 3 balls, HRC47-54 Base steel: 15Х1МФУ. 25Х1М1Ф 16CrMo4(DIN10083) 21CrMoV511, 25CrM04 St52-3 (DIN10025) | |||
| Deposition of dry gas | Veltek-N470G(Cr-Ni-Mo-V-Nb-N) 2 balls HRC40-45 Base steel: 15Х1МФУ. 25Х1М1Ф 16CrMo4(DIN10083) 21CrMoV511, 25CrM04 St52-3 (DIN10025) | 1,6—2,4 | CO 2 Ar 82Ar+18CO 2 |
| Open arc fusion | Weltek-N470S(Cr-Ni-Mo-V-Nb-N) 2 balls HRC44-50 Base steel: 15Х1МФУ. 25Х1М1Ф 16CrMo4(DIN10083) 21CrMoV511, 25CrM04 St52-3 (DIN10025) | 2,0—2,4 | self-destructive |
| Veltek-N470S.01(Cr-Ni-Mo-N) 2 balls HRC38-42 Base steel: 15Х1МФУ. 25Х1М1Ф 16CrMo4(DIN10083) 21CrMoV511, 25CrM04 St52-3 (DIN10025) |
Orlov L. N., Golyakevich O. O., Khilko O. V., Giyuk S. P. (TM.VELTEC, Kiev)
Allows increase the current resource up to 6 times for the leveled and non-reinforced ones.
Up to 80% of all steel that is smelted in the world is formed from stagnant continuous casting machines (CCMs), as an energy-saving technology that ensures high casting fluidity at the same time izatsiyu vytrat.
The productivity and efficiency of stagnation of a continuous caster is determined, first of all, by the durability of their parts, the complexity and complexity of repairs.
In the industrial metallurgy, new rollers are designed to be launched without dry coatings. For continuous fusion of continuous caster rollers, solid and powdered particles are traditionally used. 12Х13, 20Х17 in combination with fluxes AN20Sі AN26P How to ensure chromium welding of metal with a ferrite-martensitic structure? The welding process is characterized by twisted sections of the slag pick.
The structural and phase storage of the deposited metal indicates the usefulness of continuous caster rollers, which are used in cyclic and thermomechanical processes. The rollers of the knots, which are supported and unfurled, operate at a surface temperature of 670-750 °C. The rollers absorb the ferrostatic swelling and the liquid from the liquid. On straight plots, the rollers suffer from abrasive wear. The wear of the working surface of the rollers is manifested by the wear of the surface ball and the formation of cracks and cracks.
In practice, metallurgical companies in the Great Britain region have already largely adopted the following approach: “without wasting costs for the attachment and repair of continuous caster parts, to ensure a maximum installation cycle between repairs.” With this method, high-quality gas-semi-semi-sawing of nickel-based and hard-alloy coatings on the crystallizers of continuous casters is actively stagnated, and rollers from dry coatings are rolled.
The coating is applied to new rollers when they are launched at the manufacturing plant; during the hour of operation, the rollers are repaired with a new dry coating.
It is necessary to see the video before the end of the rollers gas thermal sawing. Gas-thermal filing technologies make it possible to apply almost any kind of metal or alloy to the metal surface, mixing them as needed. This makes it possible to vary the coating for various crystallizers, achieving the best performance in terms of price/wear resistance.
When applying coatings using gas-thermal filing methods, do not allow the surface of the roller to heat up to more than 150°C until the surface of the roller is heated; The original warehouse is covered even with a thickness of 0.05 mm.
Application of carbide metal-ceramic coatings to the surface of the rollers allows their service life to be extended many times over traditional methods of production and renewal.
In the practice of American and Japanese steel companies, steel rollers are often protected from high temperatures using plasma deposition of heat-insulating coatings. The coatings that are made from ceramics have a very high hardness, and at the same time have excellent heat-insulating power for the structure of their porous structure. Butter rollers with heat-insulating coatings not only prevent the sticking of butter particles onto the roller.
Corysna model is brought to galus metallurgy and possibly vicoristan in a continuous casting machine. The technical task is to improve the service life of the roller by increasing its durability. For this purpose, along the edges of the barrel, 1 roller is shaped successively in a straight line from the drive 2 and 3 support pins to the center of the barrel, 1 end 4 and middle 5 sections. In this case, the end section of the skin 4 has a dovzhina Lt.y = 0.071-0.072Lb, where Lt.y is the dovzhina of the end plot of the barrel, mm; Lb - barrel depth, mm; and metal impact with KCU = 65-70 J/cm 2 de KCU is the impact toughness coefficient of the metal.
The skin crotch section of the 5th roller is equal to the length of Lp.y = 0.035-0.036 Lb, where Lp.y is the length of the crotch section of the barrel, mm; and metal, the coefficient of impact toughness is 0.6-0.7 KCU for the metal end section 4. In this case, the end section 4 rollers are made of chromium heat-resistant steel, and the intermediate Plots 5 - made of chrome-molybdenum steel.
This model can be applied to metallurgy and can use vicoristan in the design of a continuous billet casting machine (CCM).
The outer roller of the machine for continuous casting of billets, which places the barrel, drive and non-drive axle (div. L.S. Belevsky, V.I. Kadoshnikov, E.L. Belevskaya and in. Banded rolling rolls and caster rollers. - Magnitogorsk: GOU HPE "MDTU", 2009, p.44-47).
The shortness of the driven roller has low durability due to frequent breakage of the barrel with axles, resulting in zones of high stress concentration in the metal, which are pressed by the roller during the robotic process. CCM. This significantly reduces the service life of the rollers.
The closest analogue to the object that is claimed is the roller of a continuous casting machine that places a cylindrical barrel with drive and support axles. In this case, the barrel is made of corrosion-resistant steel, fused onto the core (div. D.P. Evteev, I.M. Kolibalov. Permanent casting of steel. - M.: Metalurgy, 1984, p. 115-116).
The disadvantage of this roller is its low durability as a result of the fact that in the places where the barrel is produced with axles during the process, the voltage concentrators on the cylinder break down, and since the metal of the roller throughout the entire period has the same shock coefficient viscosity, then in certain places the metal is damaged through the lack of its plasticity. This results in a reduction in the service life of the roller.
The problem, which lies with the brown model, lies in the longer term of the roller service.
The technical result that can be achieved by the corrugated model with vicorization lies in the increased durability of the roller.
The task is to place a cylindrical barrel with drive and support pins on the driven roller of the machine for continuous casting of workpieces, according to the order of change, along the edges of the barrel the vikon is gradually grown They are drawn directly from the axles to the center of the barrel of the end and intermediate sections, and the skin of the end a section of dovzhin, equal to 0.071-0.072 per barrel, and metal with an impact toughness coefficient of 65-70 J/cm 2 and a leather crotch plot equal to 0.035 -0.036 for double kick drums and metal drums, percussion coefficient the viscosity becomes 0.6-0.7 of the impact viscosity factor of the end plate metal.
In this case, the metal of the end section of Vikoristan is chromium and heat-resistant steel.
And the metal of the middle plot is vicoristan chromium-molybdenum steel.
The essence of the bark model is explained by the chairs, where the hidden appearance of the continuous caster roller is schematically depicted.
The continuous caster roller accommodates a 1 cylindrical barrel with 2 and 3 drive axles. Along the edges of the barrel 1 there are end sections 4 and middle sections 5, which are successively stretched in a straight line from the drive pin 2 and support pin 3 to the center of the barrel 1. In this case the end section 4 may double (Lp .у), equal to 0.071-0.072 dovzhini Lb ) barrels 1, and made of metal with an impact toughness coefficient (KCU), equal to 65-70 J/cm 2 as vikoristan, most importantly, chromium heat-resistant steel, for example grade 20X13. Skin crotch section 5 barrels 1 may be dovzhin (Lp.u), equal to 0.035-0.036 dozhni (Lb) of barrel 1, and metal, impact toughness coefficient of which is 0.6-0.7 coefficients Impact toughness of metal , from any connection between the end section 4 and the metal of the middle section 5 of the vicoristan chrome-molybdenum steel, for example, grade 35 KhMFO. middle plots 5, Vikonana with metal s KCU=40-45 J/cm 2 for example, s steel grade 25X1M1F.
It is stated that the structural design of the roller allows the creation of zones of smooth change in mechanical strength of the metal, and itself, impact toughness, on the sections of the roller, which are especially resistant to damage to the metal due to the influx of dynamic forces in the process of operation. Moreover, the change in the values of power in the metal of the roller is ensured both on the surface and in the overall volume by an incremental change in the impact toughness of the metal straight from the edges of the roller to the central part. As a result, the installation on both sides of the roller, end 4 and middle 5, of metal sections with different impact toughness coefficients will ensure a smooth damping of the stress that develops during operation, the stress on the straight from the edges of the roller to the center, taking care of the guilt voltage concentrators at the main points of the roller barrel 1 with axles 2 and 3, which protects the metal from damage in designated areas of the roller. This results in an increase in the durability of the roller, and therefore a significant increase in its service life.
It is not enough to bend the end sections 4 rollers, make the dovzhina (Lt.u) less, the bottom is 0.071 Lb, de Lb - the dovzhina of the barrel is 1, mm; for metal with KCU less than 65 J/cm 2 and connected to them are intermediate sections 5, dovzhin (Lp.u) which is less than 0.035 Lb, for metal with KCU less than 0.6 KCU for metal end section 4, so as in In this case, you should be careful about the intense wear of the metal roller in the area of the production of the barrel 1 with axles 2 and 3 under the infusion of high impact pressure (voltage) during the roller robot process, so as to reduce the term of the roller services
It is also insufficient to bend the end sections 4 rollers, which have a tension (Lt.u) of more than 0.072 Lb, from metal with KCU, which exceeds 70 J/cm 2 and connected to them are the intermediate sections 5, the tension of which is greater 0.036 Lb, s metal , the impact toughness coefficient (KCU) exceeds 0.7 KCU for the metal of the end sections of 4 barrels of 1 roller, as a result of which the excessive displacement of the end sections 4 and the middle 5 sections will not be ensured have a smooth voltage extinguishment that breaks down when the roller is running, on vigin straight from the edges of roller 1 to the center, which will lead to the voltage concentrators in the places connecting them with the barrel 1 of roller and breaking yogo. The term for the video service will change.
The roller is prepared to be made using the method of electroslag remelting with a special flux (slag), which ensures a high-yield monolithic connection to the metal of the end sections 4 barrels 1 in line with the support 3 and drive axles 2, as well as the monolithic connection of the metal of the intermediate plots 5 with the metal the central part of the roller, and with the metal of the end sections 4 barrels of 1 roller.
Here's a video that will be announced as a matter of urgency.
First installed in the roller section of the continuous caster on two or three supports, the rollers in pairs (lower-upper) wrap and move the workpiece pressed between them without recasting. In this case, the rollers absorb the pressure of the workpiece as it collapses on them. The fragments along the edges of the roller are formed from metal with different impact toughness coefficients, then the stress concentrators that start to vibrate begin to be smoothly extinguished directly from the metal of the end sections 4 to the intermediate sections knock 5 and go to the central part of the barrel of 1 roller. As a result, metal wear is avoided in designated areas of the roller, and the durability of the roller is improved.
Thus, the design of the roller, as stated, allows you to increase the service life by 10-15% for the increase in the durability of the roller. So, for example, the durability of the roller taken as a prototype is no more than 2000 melts, at that time the durability of the roller, the last traces of what was observed in the minds of the CCM 1 robot in the ferrous-converter shop of VAT "MMK", amounted to 220 0-2300 heats.
1. The roller of the machine for continuous casting of blanks, which places a cylindrical metal barrel with drive and support axles, which is cut so that along the edges of the barrel the viscos are successively moved straight from the axles to the metal center the other part of the barrel is the end and middle section, and the skin end section is dozhina, equal to 0.071-0.072 dozhina barrels, and metal with an impact toughness coefficient equal to 65-70 J/cm 2 and the leather crotch plot is dozhina, equal to 0.035-0.036 Dovzhiny kick drums, and metal, drum ratio in The toughness of the end plate is 6-0.7, the impact toughness coefficient of the metal
2. The roller according to claim 1, which is distinguished by the fact that the metal end plates are vicoristan chromium heat-resistant steel.
3. The roller for item 1, which is distinguished by the fact that the metal of the intermediate section is vicoristan chromium-molybdenum steel.
It can be used for welding repairs and can be used during the repair of continuous machine casting rollers, hot rolling rollers and other metallurgical parts.The rollers of the secondary cooling zone are operated in folding basins - in the basins of cyclic thermomechanical infusion from the side of the pellet, oxidizing infusion of the cooling pellet, abrasive liquid scale of the pellet, etc. As a result, the rollers come out smoothly due to wear and tear and repair of thermal cracks.
A popular method for upgrading rollers in continuous casting machines, which includes fusing the rollers with a wear-resistant alloy (Leshchinsky L.K. Improving the service life of welded roller direct machines for continuous casting // Zvaryuvalne vyrobnitstvo. 19 91. N 1. pp. 9-11). However, the known method has a low resistance of fusing rollers after the preparation of the welded ball.
The closest method to modernization of rollers is claimed to be, in which surfacing materials are vicorized darts of type Sv-08, Sv-08A, Np-30KhGSA with a diameter of 3-4 mm, deposited on a jet of 300-400 A under flux AN -348A (Grebennik V. M., Gordienko A.V., Tsapko V.K. Improvement of the reliability of metallurgical equipment. M.: Metalurgiya, 1988. pp. 478-479). A shortcoming of the known technical solution is the low durability of the rollers through the preparation of the welded ball. Vifarbovuvaniya is prevented through a decrease in the mechanical power of the metal roller in the fusion zone. The technical task of the roller is to ensure a clear fusion of the surface of the roller barrel, which includes the preparation of the fused roller ball during its operation.
The task is to achieve that after heating the roller barrel to a temperature of more than 150 o C, melt the deposited wear-resistant ball in modes that will ensure the wear of the force of the welding jet (A) to the welding fluidity (m/year) no more 17.5 and at the used strength of the brewer struma. (A) to a heating temperature (o C) slightly greater than 3.0. After complete melting of the roller, it is subjected to thermal processing: heated at a temperature of no more than 80 o C/year to a temperature of 470-500 o C, exposed for 7-8 years and cooled at a temperature of no more than 80 o C/year. more than 80 o C/year up to a temperature of 120 o C, far away in the wind.
Preheating should be at least 150 o C to promote the formation of welded structures and cracks during the fusion process. After increasing the temperature of the pre-heating process, keep it at the same level of alloying of the roller material and especially instead of the carbon. During the welding process, it is necessary to select welding modes in such a way that the welding jet force (A) is reduced to welding fluidity (m/year) no more than 17.5. Research has established that with a large coefficient of interest, a sharp increase in heat input is avoided, which leads to overheating of the metal that is being fused, the roller barrel, as a result, an increase in If grains are removed from the weld zone, the mechanical characteristics of the metal are reduced. As a result, during the operation, for example, of the rollers of continuous casting machines, which are subject to high pressure on the side of the cream, the welded ball is formed, and cracks arise in the middle of the bead. This zone is on the side of the base metal (roller barrel).
During the process of fusing a wear-resistant ball, it is necessary to maintain the pressure of the welding jet (A) to a preheating temperature (C) of no more than 3.0. For a higher value of the coefficient, overheating of the base metal (roller barrel) is also avoided, which leads to the preparation of the deposited metal.
To change the level of excessive welding stresses, which also affect the preparation of the welded metal, immediately after the welding roller is subjected to thermal treatment: heat up to a speed of no more than 80 o C/year - for changes This increases the temperature difference, and therefore the voltage between the surface and the core of the roller. After heating, the windshield is vibrated at a temperature of 470-500 o C for 7-8 years, which will ensure maximum reduction of excess stress without significant damage to the deposited ball. After winding to prevent roller deformation and repair cracks, increased cooling is achieved with a fluidity of no more than 80 o C/year to a temperature of 120 o C outside.
Butt of the Vikonanny way. The deposits are applied to the roller barrel of a machine for continuous casting of blanks with a cob diameter of 300 mm. Roller material – steel 25Х1М1Ф. After removing the roller barrel to 285 mm and installing it on the surfacing installation, the barrel is heated with gas flames at a speed of 70 o C to a temperature of 190 o C. Surfacing is carried out with a Sv-12X13 dart and AN-20S flux. Deposition mode: jet 400 A, nozzle voltage 32, deposition speed 30 m/h. The pressure ratio of the welding jet to the melting fluidity becomes 13.3 and the pressure ratio of the welding jet to the preheating temperature becomes 2.0. The temperature is controlled by an optical Kelvin pyrometer. After complete melting of the barrel, the roller is placed near the stove, heated at a temperature of 70 o C to a temperature of 480 o C, exposed for 7 years and cooled at a temperature of 70 o C/year to a temperature of 120 o C, then there is a chill in the wind.
The advantage of the claimed method of updating rollers lies in the fact that when this method is frozen, the deposited ball is prepared daily during the operation of the roller.
2.4 Materials of caster rollers
The roller is prepared from a central-cast billet made from steels 25Х1М1Ф, 40ХГНМ, Х12МФЛ.
This method of casting, as a rule, when preparing a new continuous caster roller, the special features of the off-center casting allow the prepared barrel to be casted without welding the surface ball. Next, even during repairs, the barrels are welded to a surface ball with increased hardness.
2.4.1 Let’s take a look at the video made from steel 25Х1М1Ф:
Powers have become:
1) Chemical warehouse:
Table 1
2) Temperature of critical points:
Ac1 = 770 - 805, Ac3 (Acm) = 840 - 880
3) Physical power of the material:
Table 2
T - Temperature, for which tribute to power is taken away, [Grad]
E- Modulus of elasticity of the first type, [MPa]
a - Thermal (linear) expansion coefficient (range 20o - T)
l- Thermal conductivity coefficient (thermal capacity of the material), [W/(m deg)]
r-material strength, [kg/m3]
C - Thermal capacity of the material (range 20o - T), [J/(kg deg)]
R - Pitomiy elektroopir, [Ohm m]
3 Special part
3.1 Possession and materials
3.1.1 Turning before and after surfacing is carried out on turning benches with a center height and inter-center height that allows a 1M63 type roller to be secured in them.
3.1.2 Carry out surfacing on a standard surfacing installation UDGN – 401, designed for surfacing wrapping bodies.
The fusing head is equipped with gas (fusing pin for fusing with an electrode that melts in dry gases, reducer-vitratomer, mixer, gas valve, gas cylinder) equipment.
The installation for fusion with dry gases is fully equipped with a pump and a tray for collecting water. Water is supplied with a pump to cool the pad and small rollers (< 200 мм) диаметров. Сварочный выпрямитель должен имеет жесткую (пологопадающую) характеристику.
3.1.3 Elektropich N-60 for heat treatment of rollers with heating temperatures up to 400°C and working space dimensions.
3.1.4 The welding of continuous caster rollers is carried out with heat-resistant stainless steels, which ensures the hardness of the welded ball NYAS E 32…47.
Sv-06Х19Н10М3Т – for crystallizer rollers, bender rollers.
Np-20Х16МГСФР, Нп-30Х16МГСФР – for rollers that it is important to try mechanical wear;
Sv-12Х15Г2 with critical cracking of the roller barrel;
Sv-10Х14Г14Н4Т – for welding of landing parts and reinforcements, bender rollers.
Dry gas "Ag+CO 2 10%".
3.1.5 For balls to be transferred to a worker (sub-ball), it is allowed to freeze the Sv-08G2S dart, dry the middle - “Ag + CO 2 10%”.
3.1.6 Grinding of rollers is carried out on a 3K228A cylindrical grinding bench.
3.2. Preparatory operations
3.2.1 Groove for welding
3.2.1.1 Groove of fits for oil seals and bearings - to a depth of 1.5 mm on the side or 3.0 mm per diameter of chair size
3.2.1.2 Grooving the roller barrel
Table 3
| № | Znіmannya on b_k, mm | Umovi |
| 1 | If the roller was not sharpened to a repair size | |
| 2 | If the roller is re-sharpened to a repair size or to remove cracks and cracks | |
| 3 | To remove particularly large cracks, I opened |
3.2.1.3 Mode of turning rollers under fusing with VK8 cutting tools, with cutting cooled with emulsion:
cutting speed – 40 m/hv;
feed – 0.25-0.4 mm/rev;
cutting depth, mm – 1-2 mm;
the head cut of the plane is 60°.
3.2.1.4 Turn on the cutaneous surface of the goiter and write down the actual diameter with a marker
3.2.2 There is no need for special preparation of the floating drill before welding, because It is resistant to atmospheric corrosion and is not susceptible to rust
3.2.3 Rollers with a diameter of over 200 mm are heated along the edge of the weld to 100°C
3.3 Surfacing
3.3.1 The remaining (working) ball is liable to fuse on the surface with a diameter smaller than the nominal one by 4.0 ±0.2 mm. In this case, the turning allowance is 1.5+1.0 mm per side (3.0+2.0 mm per diameter)
3.3.2 In order to remove the additional groove under the welding, the welding of the ball that is transferred to the remaining one (piston ball) must be carried out “to size” in order to ensure the diameter of the surface, which is consistent with the groove for step 1 in Table 1
3.3.3 When depositing “Ag+CO 2 10%” in sumisha, it is important to stop at the foot. Vitrata sumishi -10-15 l/xv
The brewer must be fed continuously, not get dirty, not rub against the sharp edges and remove chips, otherwise there may be a disruption in the stability of the arc process.
It is not possible to allow excessive wear of the sharpening tip, which could lead to “shotgun” and sticking of the tip; worn - replace it promptly.
The process of transferring molten metal during strums above 270A is due to the mother's struminous character; The sharp transfer indicates the insufficient value of the flow and voltage. To increase the welding jet, increase the flow rate of the welding jet or the voltage to the nozzle.
The stability of the arc process due to jet transfer is only possible with an optimal amount of heat and an optimal value of voltage on the nozzle.
Important:
The end of the electrode dart and the jet tip were located in the center of the gas nozzle. Otherwise, through the unclear protection of the cooking bath with a chemical gas, it is possible to complete the process. With good gas protection, the surface of the straightening rollers has a yellow or light dark blue color, rather than gray-black;
the distance from the nozzle to the surface of the part that is being fused became no more than 15...20 mm;
The distance between the nozzle and the end of the jet tip was approximately 5 mm;
The height of the electrode tip becomes approximately 20...25 mm, which extends from the end of the jet tip to the surface of the part that is being fused.
As a result, with a well-adjusted process, the arc appears to be just humming without fluttering or crackling, and the voltmeter and ammeter needles move without a slight oscillation.
3.4 Updating the fit of caster rollers under the oil seal and bearing
Worn and damaged roller fits can be renewed using the fusion method. The modes of turning the landings are the same as when turning the roller barrel. Welding of the seating areas under the bearings and strengthening is carried out with a dart Sv-10Х14Г14Н4Т, Ø1.4... 1.6 mm at the center “Ag+CO 2 10%”. On the vessel with the roller for cooling, which is being melted, water is supplied at a rate of 2-3 l/h. Using the method of acid melting of the groove, start fusing the neck from there.
3.5 After-sales operations
3.5.1 After fusion, the rollers are placed in a thermostat (electric oven) at a temperature of 400°C, left for 4 years, allowed to cool down immediately from the oven to 100°C, then removed
It is allowed to cool the roller in the adjacent workshop until release, in which case the roller barrel must be completely covered with asbestos cloth, and the temperature in the workshop should not be lower than 10...15 ° C without stretching.
3.5.2 Growing the roller to the working size is carried out in 3 passes: the first is rough, the other is semi-finish, the third is finishing. Finishing modes are indicated in table No. 2
Table 4. Modes of mechanical processing of continuous caster rollers
| № | m/o modes holy material, hardness (HRC) | Brand of cutting | V cutting, m/hv. | S mm/pro. | t, mm | Number of passages |
| 1. | Chornoviy Prokhid Sv-12Х15Г2, NP-20Х16МГСФР, Sv-06Х19Н9МЗТ, Sv-10Х14Г14Н4Т | VK-8 | 33-39 | 0,4-0,5 | 1,5 | 1 |
| 2. | P/finishing and finishing pass | VK-8 | 45-72 | 0,15-0,2 | 0,15-0,3 | 2 |
| 3. | Chornoviy Prokhid 30X16MGSFR, (NKS 48-52) P/finishing and finishing pass | VK-8 | 25-30 | 0,2-0,3 | 1,5 | 1 |
| VK-8 | 35-55 | 0,15-0,2 | 0,1-0,2 | 2 |
3.5.3 Local defects (pores, lack of fusion) after black turning, boil them with an argon arc with an additional dart, similar to fusion. Single pores with a diameter of less than 1 mm are allowed, no more than 5 pcs. per barrel
3.5.4 Defects that occupy a significant area (path from the edge) are subjected to further grooving and further welding following this instruction
3.6 Come in safely
3.6.1 Before fusing the caster rollers, persons are allowed who have the right to operate automatic fusing installations and have verified the knowledge (under signature) of the provisions of these instructions.
3.6.2 When resurfacing continuous caster rollers, it is sufficient to follow the relevant instructions from the safety instructions for those operating on automatic surfacing installations, manual argon arc welding machines, lathes, thermostats and slingers.
3.6.3 Particularly unsafe factors and approaches to avoid them when updating continuous caster rollers:
Damage to the eyes with slag smears when beating a slag pick - treat the eyepieces;
Damage to the eyes and skin due to light-colored argon arc treatment - apply in eyepieces to protect the eyes from ultraviolet radiation, use light-colored filters and light-colored screens.
Table 5 Modes of deposition of continuous caster rollers
| № | Roller Ø, mm, length, mm. | Ø, mm. | Deposition modes | |||||||
| Brand dart | Zakhist | t croc, mm/pro | m/year n pro/hv | |||||||
| Ø pr. | Ø fill | |||||||||
| 1 | Ø100 * L = 630, 300, 202, 134. | Sv06Х19Н10М3Т, Ø1.4 | 230-240 | 28 | 5,5 | |||||
| 2 | Ø150 L=565, 435. | Sv10Х14Г14Н4Т Ø1.4 | ---- | 270-280 | 29 | 6,5 | ||||
