6300KVA Electric Arc Furnace Solution

1. Overview

The 6300kVA electric arc furnace is designed and manufactured according to GBl0067.14 "Basic Technical Conditions for Electric Heating Equipment". It is used for alloy smelting, the furnace body is fixed, one tap nozzle and one slag outlet are included.

2. Mechanical Structure Description

The 6300kVA high-titanium slag electric arc furnace is a fixed furnace body. The top of the fume hood is charged, and the tapping nozzle is in the form of tapping. It consists of the following parts: furnace shell, water-cooled furnace cover, electrode lifting device, high current circuit, hydraulic system, Water cooling system, feeding device, transformer, high voltage cabinet, low voltage electrical control system, etc.

3. Furnace

The furnace body includes the furnace shell, the tapping nozzle, and so on.

The furnace shell is welded with a 16mm Q235 steel plate. To increase the rigidity, ribs are provided on the outside of the furnace shell. A tapping nozzle is opened on one side of the furnace shell, and the furnace shell is lined with refractory materials.

4. Water-cooled Furnace Cover

The water-cooled furnace cover is a device for collecting smoke and dust in the furnace. It can be placed on the furnace shell or on the furnace mouth operating platform. The water-cooled furnace cover is made of 20g seamless steel pipe. The entire furnace cover must be well insulated to the ground, generally not less than 0.2MΩ. There is a flue on the top of the hood, and the flue is partially cooled by water. The water-cooled furnace cover is equipped with three-electrode holes, feeding holes, and observation holes.

5. Electrode Lifting Device

The electrode lifting device is composed of an electrode arm, a column, an electrode clamping mechanism, an electrode lifting hydraulic cylinder, a bracket, a guide wheel, and so on.

The electrode arm is a conductive cross arm, which is a fully water-cooled box-shaped structure made of copper-steel composite plates. The side surface of the front section of the side-phase cross arm and the front section of the middle-phase cross arm are respectively equipped with electrode clamping mechanisms. The electrode clamping adopts the form of disc spring, that is, the electrode is clamped by the disc spring during normal operation, and the disc spring is compressed by the hydraulic cylinder when the electrode is released.

The conductive part is insulated from the ground once, that is, the cross arm and the column are insulated by insulating cloth plates. The electrode distribution circle can be adjusted ± 50mm。

The column is a box-shaped central member welded by steel plates. It is installed upright in a mechanism equipped with guide wheels, and the guide wheels are in close contact with the column. An electrode lifting hydraulic cylinder is installed in the hollow column. The upper part of the hydraulic cylinder is connected with the electrode column, and the lower end is connected with the bracket. The electrode lifting hydraulic cylinder pushes the column to raise the electrode arm and electrode. When it descends, it is completed by its own weight. The connection between the column and the cross arm is through the intermediate adjustment plate, so that the connecting surface of the cross arm and the column is both an insulating surface and a separate surface, so that not only the adjustment of the cross arm is convenient, but the insulation between the column and the cross arm is also more reliable.

The electrode clamping mechanism is composed of an electrode clamping disc spring, connecting rod, brake, hydraulic cylinder, etc. The hydraulic cylinder and the disc spring realize the clamping and loosening of the electrode through the connecting rod and the holding brake. When the electrode is loosened, a hydraulic cylinder drives and compresses the disc spring to realize the electrode loosening. The bracket is used to connect the electrode lifting mechanism and the furnace cover lifting and rotating mechanism, so that the load of the electrode lifting mechanism is supported on the rotating frame of the furnace cover lifting and rotating mechanism through the supporting plate and the pin shaft.

During the lifting and lowering of the electrode, the guide wheel acts as a guide through the column. At the same time, in the process of furnace debugging, adjust the front, rear, left and right positions of the column by adjusting the position of the guide wheel to adjust the diameter of the electrode distribution circle.

6. High Current Circuit

The high-current line consists of connecting copper bars at the second outlet of the electric furnace transformer, compensators, copper pipes through the wall, cable joints, large cross-section water-cooled cables, conductive cross arms, electrode clamps, graphite electrodes, and brackets.

Copper bolts or stainless steel bolts are used to connect the water-cooled cable to the copper pipe through the wall and the conductive cross arm. Through-wall copper pipes, water-cooled cables, and conductive cross-arms are cooled by water.

7. Hydraulic System

The pressure of the hydraulic system is 12MPa, and the working medium is water-glycol. The system includes hydraulic pressure source and various control valves, accumulator tank, accumulator, pressure relay, etc. The hydraulic source has two pumps, and the liquid storage tank is equipped with temperature and liquid level control instruments.

8. Cooling Water System

The cooling water system consists of pressure gauges, thermometers, shut-off valves, water distributors, return tanks and pipelines.

The cooling water source is connected to the main water inlet pipe of the workshop, the pressure is not less than 2×lO5Pa, and the water temperature is not more than 35°C. The device is equipped with water pressure and water temperature alarms, when the water pressure is lower than the set value or the water temperature is higher than the specified value, an alarm signal will be issued.

The cooling water device is located in front of the furnace on the side of the transformer room wall, and is cooled with the furnace body through pipelines (including hoses)

The parts are connected for cooling of the furnace body, furnace cover, conductive cross arm, water-cooled cable and copper pipe through the wall.

The water for the transformer oil-water cooler is supplied by the high-level cooling water tank, and the return water is connected to the workshop return water network.

9. Compressed Air System

The system consists of pneumatic triple parts, distributors and solenoid valves.

10. Feeding Device

The feeding device is composed of a hopper, an air cylinder, a vibrating feeder, and a feeding tube.

11. Electrical Equipment

The electrical equipment mainly includes a high-voltage power supply system, furnace transformer, low-voltage power supply system, low-voltage electrical control system, and electrode lifting automatic regulation system.

Looking for an electric arc furnace or any relevant spare parts, please mail at marketing2@hanrm.com, our tech engineer will make a suitable solution for you.

Arc Continuous Caster

The arc continuous caster is also called the full arc continuous caster. The mold of the arc continuous caster is arc-shaped, and the secondary cooling device is in a quarter of the arc to form an arc-shaped casting billet in the mold. During the downward movement of the arc-shaped roller table, it is cooled by spraying water until it is completely solidified. After being fully solidified, the cast billet enters the straightening machine at the horizontal tangent point and then is cut to length.

The arc continuous caster is composed of ladle turret, tundish and conveying device, crystallizer and vibrating device, secondary cooling device, multi roller tension leveler, dummy bar and its storage platform, dummy bar removal device, cutting and collecting device, billet cutting equipment, etc.

1. Steel Drum Rotating Table

The ladle filled with molten steel transported from the steelmaking furnace is hoisted on the support frame by a crane, and then the support frame is rotated 180° above the intermediate tank to inject the molten steel into the intermediate tank. After pouring, rotate 180° to the receiving position, and hoist the empty can. When multiple furnaces are continuously poured, two steel buckets can be placed on the supporting frame at the same time. After one bucket of molten steel is poured into the intermediate tank, the supporting frame rotates 180°, and the other bucket of molten steel reaches the top of the intermediate tank.

2. Tundish

Tundish is an intermediate vessel between steel barrel and mould. The molten steel is injected into the mould from the tundish. The tundish is composed of tank body, tank cover and nozzle stopper.

3. Crystallizer

There are two types of crystallizers: curved and straight, which can be divided into three types: integral type, sleeve type and combined type. The width and thickness of the inner cavity of the combined mold can be adjusted. The crystallizer is composed of inner wall, outer shell, cooling water circuit and supporting arm. The material of the mold is mainly copper and copper-based alloys (phosphorus deoxidized copper, silver-containing copper, etc.). In order to increase the abrasion resistance of the inner wall, a thin layer of chromium or nickel is often plated. The length of the crystallizer is usually 700-900mm, the crystallizer taper is generally 0.5% to 0.9%, and the round billet crystallizer taper is 1% to 1.2%.

The vibration device of the mold generally adopts small amplitude and high-frequency vibration parameters, the amplitude is not more than 4mm, and the frequency is more than 150 times/min. The purpose of the vibrating device is to obtain a good lubrication condition for the inner wall, reduce friction, and prevent the molten steel from adhering to the inner wall.

4. Secondary Cooling Support Guide

The function of the secondary cooling supporting and guiding device is: direct water spraying can be used to cool the casting billet, supporting and guiding the casting billet and the starter chain, and preventing the deformation of the cast billet and the deviation of the starter chain. The secondary cooling guide section of the billet continuous caster is relatively simple. The slab caster adopts a close-packed roll structure with small diameter and small roll spacing. The guide section and the tension leveler are made into several fan-shaped sections, which is convenient for maintenance, replacement and arc alignment.

5. Straightening Machine

The drawing straightening machine is called a straightening machine for short. It is used to pull the dummy bar chain and the slab condensed with it out of the mould continuously and straighten the slab. It is liquid core tension straightening to use multi roll tension straightener to make the casting billet which is not completely solidified enter the tension straightener, which can improve the drawing speed and productivity.

The stretch-straightening machine of the billet continuous caster generally adopts a 5-roller pneumatic or hydraulic pressing type, the slab continuous caster adopts a multi-roll stretch-straightening machine, and the bloom and round billet adopt a single-frame stretch-straightening machine that can be replaced as a whole.

The starter chain is the "live bottom" of the crystallizer. The lower mouth of the crystallizer is blocked, and some scrap steel plates are placed on the starter head, so that the casting billet and the starter head are firmly connected, and the tail of the starter chain is clamped in the tension leveler. In the machine. After the start of casting, the starter chain head gradually condenses with the billet. After starting to draw the billet, the tension leveler forcibly pulls the starter chain and the steel billet connected to it from the mold until the billet is straightened and the starter chain is taken off, and then it leaves the continuous casting production line for storage.

6. Cutting equipment

A Shearing machine or flame cutting machine can be used to cut the casting billet. For billets with a cross-section of no more than 200mm×200mm, shears are generally used, and flame cutting machines can also be used for long-length billets. For square billets, round billets and slabs with a cross-section greater than 200mm×200mm, flame-cutting machines are generally used. There are electric and hydraulic shearing machines, and the shearing machine with a shearing force greater than 5000kN generally adopts the hydraulic type. The fire-burning cutting equipment consists of a cutting mechanism, a synchronization mechanism, a return mechanism, an end face detector, a fixed-length mechanism, and an oxyacetylene pipeline system. 

Advantage

The arc continuous caster is arranged in the quarter arc range, so its height is lower than that of the vertical bending continuous casting machine. This feature makes its equipment lighter, lower investment, and equipment installation and maintenance. Convenience.

Due to the low height of the equipment, the cast slab bears relatively small hydrostatic pressure during the solidification process, which can reduce internal cracks and segregation caused by the deformation of the bulge, which is beneficial to increase the drawing speed and improve the quality of the cast slab.

Industrial Technology Level

Commonly referred to as continuous casting technology is a variety of technologies targeted at arc continuous casting machines. The industrial technology level reached by the arc continuous casting machine can be summarized as follows:

1) Casting machine production capacity: The single production capacity of modern large-scale slab casters is generally 2 to 2.5 million t/a. The American Harper (LIV/Indiana Harbor) plant set an annual output of 3.05 million t/a in 1987. . The single production capacity of the bloom caster can reach 800,000 to 1 million t/a. The single production capacity of the billet multi-strand continuous caster can reach 600,000 to 800,000 tons.

2) Casting machine operating rate: generally above 80%, and more advanced casting machines can reach 85-90%.

3) High-speed casting: The general drawing speed of the slab continuous casting machine is 1.2～1.8m/min. The newly built No. 5 machine of the Fukuyama Plant of Japan Steel Pipe has created the highest record of 3.0m/min.

4) Multi-furnace continuous casting: Generally, the number of continuous casting furnaces is 4-6 furnaces on average, and there are also more than 10 furnaces. The twin-strand slab caster of the Porttalbot Plant of the British Steel Union (BSC) set a record of 300 continuous casting furnaces (with a molten steel volume of 102,000 tons) in 1987. The single-strand slab caster of American Steel's Gary Plant set a record of 329 continuous casting furnaces. In January 1988, the monthly output reached 318,500 tons.

5) The range of slab cross-section dimensions actually produced by the casting machine, mm:

Slab 125×650～220×2720 (strip steel, welded pipe billet), 350×1300

150×1000～320×1600 (thick plate), 310×2500

Bloom 200×200～600×670 (rod, shape, wire)

φ230～φ450, 560 octagonal (tube) shaped blank, 480×420×720 (rail beam)

Billet 80×80～145×145 (wire)

100×100～240×240 (rods, shapes, materials)

φ115～φ210 (pipe, rod, material)

6) Extensive use of computer technology: The production process and production management of modern continuous casting machines are automatically completed by computers.

Installer

The arc continuous caster has established a complete and accurate measurement control network before installation. The installation procedure can be determined according to the conditions of the construction site, the sequence of equipment arrival, and the requirements of the construction period.

The more reasonable installation procedure is to take the tension leveler as the positioning equipment and use its tangent point roll for positioning. Firstly, install the tension leveler curve section, align the tangent roll axis of the curve section with the transverse datum line, and the top elevation of the tangent roll is ± 0 (top elevation of discharge roller). After positioning the curve section of the tension leveler, it can be divided into two main operation lines for installation at the same time. One operation line is carried out from bottom to top in the reverse direction of casting flow, and the sequence is: lower frame of secondary cooling device → upper frame → upper beam → segment replacement device → segment → mould vibration bench and transmission device → transition segment → mould. The first line is the straight section of the tension leveler, and then the output roller table, dummy bar stand, dummy bar removal equipment and cutting equipment.

The secondary cooling device is the main part of the continuous casting machine. The complete set of equipment is located in the cooling room. After the fan-shaped section is installed, a large number of pipeline projects in the cooling room will be constructed immediately. According to the drawings, choose a reasonable construction procedure: equipment cooling water pipes, spray water pipes, Sector hydraulic pipes, dry oil lubrication pipes.

After the installation of the curved section and the straight section of the straightening machine, piping construction should be carried out. The sequence is compressed air pipe→hydraulic pipe→spray cooling water pipe→equipment cooling water pipe.

The hydraulic station matched with the continuous caster and the water distribution chamber of the secondary cooling device are complicated in the system and large in engineering volume, which must be carried out at the same time as the continuous caster.

The ladle rotating platform and tundish car traveling device on the casting platform should also be constructed in parallel with the continuous caster.

Looking for the continuous caster or relevant spare parts, please mail at marketing2@hanrm.com.

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Endless Continuous Casting and Rolling (ESP) Technology

In recent years, in order to save energy and reduce consumption, iron and steel enterprises in Europe, Japan, South Korea and other countries have carried out a lot of research and development work in the field of reducing hot strip steel production technology, and achieved remarkable results. Among them, remarkable achievements have been made in the development of endless rolling technology of hot-rolled strip steel, further improving the yield of the strip steel, the ratio of size and shape accuracy to thin and ultra-thin specification, realizing partial "heat instead of cold" and reducing roll consumption. This technology is another leap of iron and steel production technology and represents the cutting-edge technology of hot-rolled strip steel in the world.

In 1997, POSCO and Hitachi jointly started to develop a new endless rolling process of strip steel with shearing and welding process for intermediate billet connection. In April 1998, Nippon Steel Co., Ltd. successfully developed a steel plate endless rolling production line using a high-energy laser to realize butt welding of the intermediate slab. From 2006 to 2007, POSCO and Hitachi put into industrial production the new endless rolling process of strip steel with intermediate billet connection by shear and welding process. Based on the pendulum shear concept, this new solid-state connection process realized the innovation of endless rolling connection technology. In 2009, the world's first ESP endless casting and rolling strip steel production line jointly built by Italian steel enterprise Arvedi and Siemens was put into operation, with an output of 450000 tons.

Taking Arvedi ESP line as an example, this paper briefly introduces the process characteristics and technical advantages of endless continuous casting and rolling of strip steel.

1. ESP Process and Main Features

   （1） Introduction of ESP Process

Arvedi ESP production line is shown below. The technology is developed on the basis of Demark's ISP technology. The continuous caster in the production line adopts parallel plate straight arc mold, and the slab guide adopts a casting rolling structure. The slab is directly rolled into the blooming mill through liquid core reduction, and then can be sold off the production line after shearing. The slab without production line is heated by induction, and the strip steel is rolled into thin strips by five finishing mills and then rolled into coils after cooling. The ESP production line is the shortest continuous casting and rolling production line in the world with a total length of only 190m.

（2） Main Technical Features of ESP Process

① Higher casting speed. 

Higher casting speed can be achieved by optimizing caster configuration and increasing flexibility of thickness and casting speed. Through the mathematical simulation of the computer optimized hydrodynamic calculation and (physical) water model test, it shows that the current pouring speed of 5-6 M / min can still be greatly improved.

② Stable casting process control. 

In the past decade, the most significant improvements have been made in the stability control of slab forming and slab solidification, and the mold fluxes required for different steel grades have also been optimized. Stable control at high casting speed has been achieved by controlling friction and mold angle arrangement.

③ Wide application of automation technology. 

The key to success lies in the improvement of technological process control, sensor technology, data management and process. In the thickness control, temperature control, plate shape control and flatness control of Siemens VAI products, the central network strengthens the flexibility and standardization of the process model. For example, the "microstructure target cooling" package can control the metallurgical parameters of strip steel. In the ESP line, automation runs through the whole process from self-casting to cooling.

2. Main advantages of ESP process

   （1） Technical Advantages

① The ESP production line is the first one that can complete the hot strip rolling from molten steel to underground coiler in 7 minutes, while the original ISP thin slab continuous casting and rolling production line takes 15 minutes from molten steel casting to finished strip production;

② ESP technology is rolled at high temperature, which improves the uniformity of microstructure and improves the performance of products;

③ The whole production line is not more than 190m from the beginning of continuous casting to the coiler of finished product, which is very compact and belongs to the ultra-short process. The investment of equipment and plant is reduced, and the yield is relatively improved. The endless strip production process avoids the threading of the new coil in the finishing mill, so the thin (0.8-1.0 mm) coil can be produced safely and reliably. It is estimated that the yield of steel from molten steel to coil can reach 98.0% - 98.5%, while ISP process is only 96.5%;

④ It can produce high-quality ultra-thin strip steel, some of which can replace cold-rolled products and directly carry out pickling and galvanizing;

⑤ In the aspect of energy-saving and environmental protection, ESP technology can make full use of the high-temperature energy of continuous casting slab at high temperature, even if the larger reduction is implemented, the rolling force is also lower.

Compared with conventional hot strip mill, 2-3 reheating furnaces are reduced; Compared with CSP thin slab continuous casting and rolling, more than 200 meters long tunnel furnace is also reduced. And rolling at high temperatures greatly reduces the power of the rolling mill and the power consumption. Compared with ISP process, the Cremona furnace is canceled, but the power of the induction furnace is increased. The maximum power of ISP induction furnace is 20MW, and that of the ESP induction furnace is 36mw.

 

In addition, ESP is different from other thin slabs continuous casting and rolling processes in that it only needs little energy to improve the capacity and efficiency of the production line. At the ultimate drawing speed, i.e. 7.6m/min (70mm for blank) × 1250mm) and 8.3m/min (55mm for blank) × The energy input of the induction heater will be reduced to zero. The energy consumption of ESP is about 25% - 30% less than ISP and 40% less than traditional hot strip mill. Related to the reduction of energy consumption is the direct or indirect reduction of greenhouse gas and harmful gas emissions, which is reduced by 40% - 50% in the production of general specifications and 65% - 70% in the production of thinner specifications. In terms of water consumption, its water consumption is 80% lower than that of the best traditional production method.

（2） Advantage of Variety Structure

① Full range of steel grades

The product outline of ESP line design is a complete product range from low carbon steel to high carbon steel, as well as alloy steel, including high-grade and high-quality steel grades (such as oriented and nonoriented silicon steel, if the steel used to manufacture automobile body panels). Using ArvediESP equipment, hot-rolled products with cold rolling surface quality (Grade A) can be produced (which can be directly used for manufacturing bare parts of the automobile); Hot rolled products with the characteristics of IF steel can also be produced from converter molten steel.

② Thin specification products.

The endless rolling technology is adopted in the ESP process to reduce the number of threading. Therefore, the Arvedi ESP process can be used to produce a large number of hot-rolled products with thin specifications (thickness 0.8-1.0 mm) and Arvedi patent rights, which can replace cold-rolled products in many fields, including steel grades with yield limit of 315 MPa and thickness of 1 mm; The yield limit is 420MPa and the thickness is 1.25mm; High strength steel with thickness less than 2mm (strength 700-800mpa); Dp600-dp1000 steel with the thickness of 1.2-1.5mm can replace some cold-rolled products and increase the added value of products.

（3） Cost Advantage

ESP production line has excellent process cost advantage because it adopts endless continuous casting and rolling process and compact short process. According to the analysis [3-5], the process cost of the ESP process is about 55% of that of the traditional process, about 70% of that of other thin slab processes, and about 77% of that of the ISP process. It can be concluded that the overall product outline of ESP process is expected to have a metal yield of 98%, which is about 30% - 50% lower than that of the traditional hot strip production process. Compared with the twin-roll strip casting and rolling process, the ESP process has a good comprehensive competitive advantage and is a new process worthy of attention and expectation.

In a word, the first production line invested by Arvedi has proved the advantages of the ESP process. ESP is representative of an energy-saving and consumption-reducing environment-friendly production line. In the future, the iron and steel industry will continue to develop in the direction of energy-saving and environmental protection, high production efficiency and low consumption, and high product quality, this process has gradually highlighted its strong competitive advantages.

Provide complete solutions for Hot and Cold Rolling Mills, which includes, planning, consultancy, design, manufacturing, and commissioning of the plant. Email: marketing2@hanrm.com

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Advantages and Disadvantages of Carbide Rolls

Precautions for the Use of Carbide Rolls

1. After the carbide roll is installed, the carbide roll worker should carefully check the roll cooling water pipe and position, and then connect the introduced hose to the special water pipe. After the hose is connected, the interface must be tied tightly with lead wire to prevent the roll from being in a state of no cooling water after falling off, which may cause serious consequences.

2. During the rolling process of the roll, pay close attention to the running state of the bearing seat, and stop and check if any abnormality is found.

3. In order to reduce the occurrence of fatigue cracks, the surface of the roll ring must be cooled with water to reduce the thermal expansion of the surface. When the rolled piece is in contact with the roll ring surface, the temperature of the roll ring surface can reach 500-600℃. Cooling water sprayed on the hot roll ring surface will form a layer of gas film covering the surface of the roll ring, which will seriously affect the cooling effect. It shows that when the cooling air pressure reaches more than 0.5Mpa, the gas film will be broken, so that the cooling effect will be improved.

Low-speed rolling mill roll ring cooling water pressure should not be too high, in order to prevent the cooling water from splashing and fail to cool down, the cooling water pressure should be 3-4Mpa, and the water volume should be 40-50 cubic meters per hour. At the same time, in order to improve the cooling effect, the coverage of the cooling water sprayed by the cooling water nozzle should be correspondingly overlapped, and the outlet of the cooling water column should be aligned with the exit of the roll ring. Carbide roller rings also have special requirements for water acidity: PH≥7.2 is weakly alkaline and kept clean.

4. Water cooling of carbide rolls is an extremely important means during use. The better the cooling condition, the higher the tonnage of carbide rolls, otherwise the rolls will easily burst. Therefore, during the rolling process, each production shift should stop every 4 hours to check whether the position of the dedicated cooling water pipe is moving and whether the water pipe nozzle is blocked, and then drive the rolling.

5. When handing over the shift, the operator should carefully check the wear of the rolling slot and whether there are minor cracks. If the above happens, they should report to the quality supervisor of the dispatching room, and then replace the carbide roll groove after confirmation.

6. During the rolling process, the roll gap adjustment must not be zero-gap, that is, the roll must not be touched during rolling.

7. Once the sampling room is found to be abnormal in rolling products, the person in charge should notify the dispatching room, and the dispatching room should stop for inspection immediately after receiving the notice. If the key block of the roll matrix is protruding, the screws are loose, and the rolling groove has slight cracks, it is necessary to replace the rolling groove and the cemented carbide roll.

8. It is recommended that the single groove-rated rolling tonnage of ф5—ф8 wire is 800—1000 tons. The single groove rolling tonnage cannot be excessively higher than the specified tonnage, otherwise, the surface micro-cracks will cause the roll ring to crack, even if it does not crack, it will increase the amount of roll ring grinding, resulting in uneconomical.

Advantages and Disadvantages of Applying Carbide Rolls on Bar and Wire Rod Rolling Mills

Due to the advantages of high hardness and good wear resistance, the application of cemented carbide roll rings on bar and wire rod rolling mills shows the following advantages:

1. Improve the quality of steel products, so that the surface quality and tolerance dimensions of the steel are completely improved, and the negative deviation control is very accurate;

2. Reduce the number of slot changes, roll changes and downtime, increase the utilization rate and output of the rolling mill, and enable the rolling mill to create greater economic benefits in the same time;

3. Reduce the scrap rate of products and reduce the labor intensity of the production workshop;

4. Reducing production costs is an effective way for enterprises to increase efficiency;

5. Conducive to the application of endless rolling technology.

The disadvantages are: due to the high hardness and brittleness of cemented carbide roll ring and high sensitivity to cracks, it is difficult to maintain, and the requirement for cooling water is high in use, and it can not bear the rapid cooling and heating, otherwise it is easy to cause destructive accidents.

If you are looking for carbide rolls, please contact me.
Email: marketing2@hanrm.com.

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Roller FAQs

Cooling Bed of Rebar Rolling Mill

The cooling bed is the working table of the metallurgical steel rolling industry to cool rolled products (rebar, round steel, steel pipe, etc.). The cooling bed is composed of the mechanical transmission system, water cooling system, cooling bed table, fixed support, etc. The cooling beds mainly include gear extraction cooling bed, walking beam cooling bed, claw type cooling bed, carrying chain cooling bed, rolling plate cooling bed, etc.

The cooling bed is one of the indispensable auxiliary equipment in small and medium-sized bar mill plants. Its function is to cut double-length bar rolled by rolling mill through flying shear, transport and unload it to the rack of cooling bed for cooling, so as to reduce its temperature from 900 ℃ to 100 ~ 300 ℃. Then it is collected and sent to output roller table by unloading device of cooling bed, and then it is sent to cold shear for cutting into fixed-length finished product by output roller table. The design quality and installation accuracy of the cooling bed directly determine the final quality of products.

Equipment Composition

The cooling bed consists of three parts: cooling bed feeding device, serrated walking beam cooling bed body, cooling bed unloading device and output roller table. The cooling bed charging device is a difficult point in the design of the cooling bed, and it is also a throat device.

Feeding Device

The feeding device is composed of a roll-in roller table, a straightening plate, a brake apron and a pneumatic steel splitting device. The structural feature of the feeding device is that a hydraulic cylinder is arranged every 12m in the length direction of 120m, all hydraulic cylinders operate synchronously, and the skirt board is moved up and down at the same time through the connecting rod and the synchronous shaft.

The performance characteristics of the feeding device are: a proximity switch is set on the synchronization axis to detect and control the lifting position of the lifting skirt to ensure accurate and reliable actions; the control valve of the hydraulic cylinder is configured nearby to minimize pressure errors and ensure synchronization of actions The direct-acting relief valve and anti-cavitation valve are set in the control circuit, and the optimized design of the hydraulic cylinder can effectively solve the problem of damage to the hydraulic system caused by the huge impact and ensure the safety of the hydraulic system.

The side drive of the hydraulic cylinder, the synchronous shaft is arranged outside the high-temperature zone. When each hydraulic cylinder is kept in sync, each shaft bears only the torsional stress required for the lifting of the lifting skirt plate, while the synchronous shaft is rotated. There is almost no inertial force. Because the inertial force of the skirt is distributed to each hydraulic cylinder, the force state of the mechanism is greatly improved. 

There is an adjustment mechanism on the connecting rod, which can easily adjust the up and down position of the skirt board. Due to the optimized design of the mechanical structure, the electrical control adopts computational control technology, and the hydraulic system adopts safety measures, the device is endowed with superior performance. The levelness and straightness of all skirts are reliably guaranteed during work.

Classification

Cooling beds mainly include pull-tooth cooling beds, rack stepping cooling beds, claw cooling beds, carrier chain cooling beds, and rolling plate cooling beds.

Working Principle

The rolled products are transported into the cooling bed through the roller table, and then the workpieces arranged on the cooling bed are gradually moved to the top of the cooling bed by means of rack and gear stepping, so as to achieve the cooling effect of the workpiece.

The Main Purpose

The cooling bed equipment is mainly used for on-line slow natural cooling of rolled steel plates. In the profile production line, the cooling bed also has a pre-bending function for the profile to prevent the profile from being irregularly bent due to unequal quality in the natural cooling process. Cooling beds are mainly used in the steel industry, metallurgical industry, etc.

Operating Procedures

1. During the rolling process, the operators of the cooling bed are strictly forbidden to go on the cooling bed, and are not allowed to walk on the roller table or rack.

2. If there are accidents such as chaotic bed during production, it must be processed and cleared after the rolling stop.

3. The sampling of the cooling bed should use special tools for sampling.

4. Pay attention to the surrounding conditions during operation, and it is strictly forbidden for unrelated persons to enter the dangerous area of ​​the large cooling bed.

5. Hot waste products caused by accidents such as chaotic beds must be removed on duty to ensure that the environment around the cooling bed is tidy.

If you are interested in cooling beds for rolling mill machine, please mail at marketing2@hanrm.com.

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Presentation on Electric Arc Furnace (A)

The electric arc furnace is an electric furnace that uses high temperature produced by electrode arc to smelt ore and metal. When the arc is formed by gas discharge, the energy is concentrated and the temperature of the arc zone is above 3000 ℃. For smelting metals, EAF is more flexible than other steelmaking furnaces, which can effectively remove sulfur, phosphorus and other impurities. The furnace temperature is easy to control, and the equipment covers a small area. It is suitable for smelting high-quality alloy steel.

Introduction

Through the metal electrode or nonmetal electrode to produce electric arc heating industrial furnace is called electric arc furnace. According to the form of arc, EAF can be divided into three-phase EAF, consumable EAF, single-phase EAF and resistance EAF. The furnace body of EAF is composed of furnace cover, furnace door, tapping tank and furnace body. The furnace bottom and wall are built with basic refractory or acid refractory.

According to the transformer capacity per ton of furnace capacity, EAF can be divided into ordinary power EAF, high power EAF and ultra-high power EAF. EAF steelmaking is to input electric energy into EAF through graphite electrode, and take the arc between electrode end and charge as heat source for steelmaking. Electric energy is used as the heat source in EAF, and the atmosphere in EAF can be adjusted, which is very beneficial to the smelting of steel grades with more oxidizable elements.

Shortly after the invention of EAF steelmaking, it was used to smelt alloy steel and developed greatly. With the improvement of EAF equipment and smelting technology, the development of electric power industry, the cost of EAF steelmaking is decreasing. Now EAF steelmaking is not only used for the production of alloy steel, but also for the production of ordinary carbon steel. The proportion of its output in the total steel output of major industrial countries is rising.

Development History

In 1888-1892, p.l.t.h é roult developed coal instead of energy by using a high temperature of electrode arc, and invented an arc furnace for direct smelting. At first, the EAF was only used for the production of calcium carbide and ferroalloy, and it was developed to make steel in 1906, and thus the scrap steel could be recycled economically and in scale. The electric energy is converted into heat energy by the arc between the end of the graphite electrode and the charge, and then the furnace charge is melted and the subsequent high-temperature metallurgical reaction is completed. Because it uses electric energy and is easy to adjust the atmosphere in the furnace, it can smelt various kinds of alloy steel including the oxidizable elements.

With the development of power industry, the continuous improvement of process equipment and the improvement of smelting technology, arc furnace is widely used and its production capacity and scale are increasing. The maximum capacity of EAF was 100t in 1930s, 200t in 1950s and 400t in the early 1970s. Especially in the past 50 years, the technical performance of EAF has been gradually improved, and the production cost has decreased significantly. The proportion of EAF steel in developed countries in Europe and America has exceeded 50%. The development of modern EAF smelting technology advances with the times. 

In the 1960s-1970s, the development of ultra-high power supply and related technologies is mainly carried out. HP and UHP are compared with the general power arc furnace (RP). They are mainly divided according to the capacity of transformer per ton of furnace capacity, and there is a trend of higher and higher in recent years. This means that the heat energy of the electric arc furnace is greatly increased in unit time, which makes the melting time significantly shortened, thus improving the production capacity, reducing electrode consumption, reducing heat loss and reducing the power consumption. The result is that the production capacity is increased again, and the cost also decreases greatly. High voltage long arc operation, water-cooled furnace wall, water-cooled furnace cover, foam slag technology, and external heat source melting have been widely used in conjunction with ultra-high power electric arc furnace. Ladle refining and intensified oxygen utilization have also been adopted.

In the 1980s, the development of LF and EBT technology made the modern EAF steelmaking process of EAF smelting and refining outside the furnace mature. It is worth noting that since then, people have paid more attention to the use of secondary combustion and flue gas sensible heat, namely, the preheating of scrap steel. Different preheating methods of scrap produce different types of modern EAFs, including ordinary arc furnaces preheating with basket scrap, flue shaft furnace with supporting claws, double shell arc furnace and Consteel arc furnace. At present, the equipment and production technology of EAF are still in the process of continuous development.

Inquiry about heating furnaces, please mail at marketing2@hanrm.com.

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