Equipment for cold rolling mills. The main differences between hot-rolled and cold-rolled steel, application features AC gear motor
continuous mills with 4-5-6 stands.
Single-stand multi-roll reversing mills
These mills are used for rolling small batches of a wide range of sheets, especially from steel grades that are difficult to deform. The mills are easy to set up and can be rolled with any number of passes. In ferrous metallurgy, quarto and 20-roll mills are most often used.
On single-stand mills, two rolling methods are used:
sheet rolling lead to the quarto cage. The initial workpiece is a hot-rolled pickled sheet with a thickness of 3-10.5 mm; final thickness of rolled sheets up to 1.5 mm.
Rolling strip. Rolling is carried out in 20 roll mills with a diameter of work rolls D p=3-150 mm, barrel length L b = 60-1700 mm.
The assortment of such mills includes thin strips with a thickness of 0.57-0.60 mm, width up to 1700 mm. The initial workpiece is pickled hot-rolled coiled strip with a thickness of 3-4 mm. When rolling tapes with a thickness of 0.002-0.10 mm the initial workpiece is a cold-rolled strip with a thickness of 0.03-1.0 mm, which has undergone "bright" annealing.
Single-stand reversing mills are equipped with winders on the front and rear sides. Rolling is carried out in several passes, rewinding the strip from one winder to another, with high strip tension between the winders and the working stand, with the obligatory use of technological lubricants to reduce the effect of friction forces on the rolling force. On fig. 33 shows a diagram of a twenty-roll cold strip mill.
Rice. 33. Scheme of a twenty-roll cold rolling mill:
1 - work rolls; 2 and 3 – intermediate and back-up rolls; 4 – strip thickness gauge; 5 and 7 – tension devices; 6 - band; 8 – winder drums
The mill has only two working rolls that deform the strip. The remaining rolls are supporting and are designed to reduce the bending of the work rolls.
Continuous thin strip cold rolling mills
Continuous mills are used for significant production volumes of a relatively narrow assortment of strips. Modern continuous mills consist of 5-6 non-reversible quarto stands, the strip is located in all stands at the same time. Only one pass is made in each stand. Continuous mills are equipped with a decoiler at the front and a winder at the back.
The rolling stock for continuous cold rolling mills is hot-rolled pre-pickled coils with a lubricated surface. Hot-rolled coiled strip is obtained from continuous wide-strip hot rolling mills. The thickness of the rolling is, depending on the thickness of the finished product, 2-6 mm.
During cold rolling, high pressures of the metal on the rolls occur due to the hardening of the metal in the process of deformation and the large influence of external friction forces. Cold rolling of the coiled strip is carried out with a significant tension of the strip between the stands and between the last stand and the winder with the obligatory use of technological lubricants. The tension of the strip provides a significant reduction in the pressure of the metal on the rolls, which allows rolling the strip with high reductions for each pass and contributes to the tight winding of the strip on the winder and its stable position between the rolls, the strip does not move along the barrel of the roll. The use of technological lubricants leads to a decrease in the influence of friction forces, a decrease in the pressure of the metal on the rolls.
Strips with a thickness of 0.2-3.5 are rolled on 5-stand continuous mills mm, on 6 cages with a thickness of 0.18-1.0 mm. The width of strips rolled on these mills is up to 1200 mm.
On continuous mills, two rolling methods are used:
Coil rolling strips. Each roll is rolled separately.
Endless rolling of the rolled strip. Adjacent rolls are butt welded before rolling.
Diagrams of continuous coil rolling and endless rolling mills are shown in Fig. 34.
Rice. 34. Schemes of continuous roll mills ( a) and
infinite ( b) rolling:
1 - unwinders; 2 – working stands; 3 - winders; 4 - scissors; 5 - butt welding machine; 6 - loop-forming device; 7 - flying scissors
During roll rolling (Fig. 34, a) pickled hot-rolled coils from the warehouse are fed by crane to the conveyor in front of the cold rolling mill, from which they are fed one by one to the decoiler. Then the lever with an electromagnet is lowered, the magnet attracts the end of the roll, lifts it up and feeds it into the feed rollers. These rollers feed the strip further into the lead-in, which clamps and sets it into the rolls of the first stand.
The rolling process starts at a low filling speed of 0.5-1.0 m/with. The strip is fed into the first stand, passed through the rolls of all stands and directed to the winder drum. When 2-3 coil turns are formed on the winder drum, the mill is accelerated to a working speed of 30-40 m/with. When passing through the rolls of the rear end of the strip, the speed is reduced again. Since most of the strip is rolled at a variable speed, this leads to a change in the rolling conditions, rolling force, elastic deformation of the stand, and, ultimately, to a change in the thickness of the strip along its length.
A significant improvement in the quality of the strip is achieved on endless rolling mills (Fig. 34, b), on which the ends of the rolls prepared for rolling are welded in the flow in front of the mill. As a result, front end filling operations are reduced, the rolling speed is reduced only when welds pass through the rolls, respectively, productivity increases and the metal consumption coefficient decreases. The continuity of the process at the time of welding the ends of adjacent rolls, which require stopping the strips, is ensured by the presence of a loop accumulator 6 . When the coil welding process ends, a loop accumulation of the strip is created again, after leaving the last stand, the strip is cut with flying shears 7 and winds up on winders 3 .
At present, 50-70% of thin sheets are produced at strip mills. Products manufactured on continuous mills are characterized by good surface quality and high precision. The annual productivity of continuous wide strip hot rolling mills reaches 4.0-6.0 million.t.
Due to high productivity and a high degree of mechanization and automation, the cost of finished products obtained on these mills is significantly lower than the cost of products of other strip mills.
Continuous broad strip mill 2000
On fig. 31 shows the layout of the equipment of a modern continuous broad strip mill 2000.
Rice. 31. Layout of equipment for continuous
broad strip mill 2000:
1 – heating furnaces; 2 -5 – working draft stands; 2 – vertical roughing two-roll scale-breaking stand; 3 – two-roll stand; 4 – universal four-roll stand; 5 – a continuous three-stand subgroup of universal four roll stands; 6 – intermediate roller table; 7 – flying drum shears; 8 – finishing scale breaker; 9 – continuous finishing group; 10 – discharge choking roller conveyors; 11 – winders for strip thickness 1.2-4 mm; 12 – trolley with roll turner; 13 – winders for strip thickness 4-16 mm; 14 – turntable for rolls; 15 – roll conveyors
The mill is designed for rolling strip steel with a thickness of 1.2-16 mm and width 1000-1850 mm. Cast and rolled slabs up to 300 mm thick are used as starting material. mm, up to 10.5 m and weighing 15-20 t from carbon and low alloy steels. All mill stands are divided into two groups: roughing (stands 3-5) and finishing continuous (stands 9). The roughing group consists of one stand with horizontal rolls 3 and four universal stands with horizontal rolls with a diameter D p = 1600 mm and vertical rolls with a diameter D in = 1000 mm(cages 4 and 5 ). A feature of the mill is that in the roughing group the last three stands are combined into a continuous subgroup 5 . This made it possible to reduce the length and improve the temperature regime of rolling by reducing heat losses.
Continuous finishing group 9 includes seven four-roll stands (quarto stands) with work roll diameter D p = 800 mm and backup rolls D op = 1600 mm. A rough scale breaker is installed in front of the first stand of the roughing group 2 , which provides preliminary breaking of the furnace scale and forms the exact dimensions of the slab in width. The loosened scale is knocked off the surface of the slab by hydraulic blasting under pressure 15 MPa.
Before rolling, the slabs are heated in four process furnaces 1 with walking beams up to a temperature of 1150-1280С.
The heated slab is pushed out of the furnace and fed by a roller table to the rough scale breaker, and then to the roughing group stands. The vertical rolls of the universal stands compress the side edges of the strip, preventing the formation of a bulge and, as a result, breaks in the sheet edges during rolling. After the roughing group, a strip with a thickness of 30-50 mm intermediate roller table 6 transferred to the finishing group. Flying shears are installed in front of the finishing group 7 , designed for trimming the front and rear ends of the strip and a roller finishing scale breaker 8 , which loosens the air scale and removes it from the surface of the roll with jets of water under high pressure.
When the roll approaches the finishing group, the temperature of the metal is usually 1050-1100С, when leaving the last finishing stand it is 850-950С. In order to reduce the temperature of the strip during winding and thereby improve the structure of the metal, in the section from the finishing stand to the winder, the strips are intensively cooled to 600-650°C using shower devices and wound into a roll on one of the five roller-drum winders. On winders 11 strips with a thickness of 1.2-4 are wound mm, on winders 13 – strips 4-16 thick mm.
The rolled strip is fed into the cold rolling shop or for finishing, which includes unwinding the rolls, transverse cutting into individual sheets and laying the sheets or slitting along the width of the strip into individual strips, which are wound on coilers into riots.
Comparing two identical samples of steel obtained in different ways, it is impossible to say unequivocally which one is better. But taking into account the specifics of the use of metal products (whether it be a sheet or a rod), in each specific case it should be understood what properties the alloy acquires during one or another rolling of blanks (“slabs”). This is necessary not only in order to make the best choice and not overpay for products (especially if a large batch is being purchased).
Sometimes the difference between hot-rolled and cold-rolled products is fundamental.
The information presented in this article will be of interest to the average consumer and will definitely help to make the right decision. But it is also useful for a professional to familiarize himself with the proposed material, since it is always useful to periodically refresh his memory.
The main difference in the methods of rolling is in the temperature at which the workpieces are processed. When hot, it exceeds 920 ºC (1700 ºF). Cold rolling is carried out in a more gentle mode, and the temperature is significantly lower than the value (sometimes at room level) at which a particular metal (alloy) recrystallizes.
Note
Recrystallization is a process in which equiaxed grains (granules) are formed and grow. Occurs with a significant increase in temperature and changes the structure of the material, which acquires other properties.
Rental Features
Hot
- Metal (alloy) is easier to process, therefore, with this rolling method, thinner sheets or a smaller section bar can be obtained.
- For the manufacture of products by hot rolling, low-grade, cheaper steel is mainly used.
- There is a need for further processing of products, as they are often covered with scale.
- The geometry of hot-rolled specimens does not differ in severity (for example, unevenness at the corners of sheets, uneven thickness), since it is impossible to accurately calculate the limits of deformation during metal cooling.
Calculation of the mass of hot-rolled and cold-rolled sheets according to GOST 19903-90, 19904-90:
- Reinforcing (reinforcing).
- Bearing (foundation).
Cold
- This method of rolling allows you to accurately maintain the specified dimensions of the products.
- The surface of the resulting samples is smoother, even, so their subsequent processing is minimized (and sometimes not required at all).
- Cold-rolled metal becomes harder and stronger (for bending, stretching, tearing) with a uniform structure over the entire area.
- Goes into production.
- The higher quality of cold rolled steel increases its cost.
Output
If in the first place is the cost of rental, then preference should be given to hot. When the determining factor is the appearance, strength, quality, then cold-rolled samples should be purchased.
Main advantages of 2-roll rolling mill
The features of 2-roll reversing cold rolling mill are as follows:
Reversible cold rolling mill with decoiler and 3-roller feeder
Although the proposed reversing cold rolling mill will be designed with two reels, production capacity can be increased with an additional unwinding reel. This minimizes initial investment costs and guarantees future capacity expansion.
Main Features of 2 Roll Reversing Cold Rolling Mill
- Hydraulic tightening screws
- Automatic thickness control system
- Automatic deceleration and autostop
- Cooling section control
- Cleaning system
- Automatic tension adjustment
- Quick change of work rolls
- Automatic thickness control system with constant mass flow for strip thickness control (option)
- HMI interface
- Roll line adjustment
Distinctive features of the 2-roll rolling mill
- Highly efficient production with high elongation ratio for the same specific roll pressure
- Cylindrical work rolls
- Tackle with high dimensional accuracy
1.1 Entrance equipment
1.1.1 Roll rack for unwinding drum
Description
This roll rack is located on the operator's side and is designed to receive the roll from the overhead crane and store the roll in front of the unwinding drum.
Technical data
1.1.2 Trolley for lifting the roll onto the unwinding drum
Description
This roll trolley is positioned perpendicular to the rolling line near the unwinding drum and is designed to transport rolls from the roll rack to the unwinding drum.
The movable deck plate is designed to cover the open pit when the bale trolley is under the mandrel of the unwinder. It will be attached to the carriage and move on it.
Technical data
1.1.3 Unwinding drum
Description
We assume that the winding of the roll is conventional, with tension, and not spiral. If the coil winding is spiral, then we will offer another unwinder system.
The unwinding drum is located in front of the entrance to the input tension drum and is designed to feed the strip into the mill.
The material is fed to the unwinding drum by an unwinding drum trolley moving horizontally.
The decoiler will be of suspended type with a closed drive.
The drum head consists of four segments. It is unclenched with the help of a hydraulic cylinder, wedge-shaped segments. The mandrel expands to a nominal diameter of 600 mm.
The shock roller will be lowered by means of a cylinder to facilitate the strip threading process.
Technical data
1) The actual drum
Technical data
2) Cushion roller
1.1.4 Roll measuring device
Description
The height of the centering device is used to measure the outside diameter of the roll in order to center the unwind mandrel and the roll on the trolley. The width of the centering device is used to measure the width of the roll in order to align the center of the mandrel of the unwinder with the center of the roll on the trolley.
It consists of a welded steel frame and photocells.
Technical data
1.1.5 Roll feeder with roll end deflector and filling table
Description
The strip feeder is designed to bend and feed the front end of the roll to the inlet section of the mill.
It consists of an upper roller, a lower roller, a kink roller, an input gauge and a filling guide, and an output filling table.
Inlet gauge and refill guide of rotary type, with a special blade made of special tool steel on the hydraulic cylinder.
The lower roller is a freely rotating steel roller mounted on a welded metal structure. The top roller is mounted on a swing arm at the top of the base, with a hydraulic cylinder. Driven by AC gear motor. current through the universal joint.
The folding roller is brought to the front edge of the roll. This is a freely rotating roller mounted on a welded metal structure.
The filling table at the exit is a welded metal structure.
Technical data
1.1.6 Inlet drum and idler drum
Description
The drum and tension drum are located on the inlet side of the mill and are designed for winding and unwinding the strip before or after rolling.
Drum and tension drum suspended type with closed drive.
The base plate is a thick plate. It is mounted on lubricated machined guides with replaceable bronze linings.
The head of the drum and tension drum is one drum and four wedge-shaped segments. The drum head has a clamp for the end of the roll with a hydraulic valve. The head of the tension drum is unclenched by a rotating hydraulic cylinder mounted on the drive side of the drum mandrel. The mandrel expands to a nominal diameter of 500 mm.
Technical data
| 1) Drum | |
| Quantity: | One pack |
| Roll size | |
| ext. roll diameter: | max.Φ2,000mm |
| roll inner diameter: | Φ1200mm |
| Roll Width: | 400 mm |
| Winding and unwinding speed: | max 80 m/min |
| 2) The drum itself | |
| Quantity: | One pack |
| Roll size | |
| roll outer diameter: | Max. Φ2,000mm |
| internal Roll diameter: | Φ600mm |
| roll width: | 400 mm |
| Winding and unwinding speed: | max 80 m/min |
| Max. roll weight: | 5000 kg |
| Winding direction: | top/bottom of dispenser |
| Body and base: | Welded mild steel construction |
| Wedge pad: | Bearing with bushings |
| Mandrel and stem: | material SCM 440 |
| Length: | approx. 550mm |
| Segments: | SC46 |
Technical data
2) Cushioning roller for drum and idler drum
3) Outer bearing (drum support)
1.7 Roll entry trolley
Description
This roll trolley is positioned perpendicular to the rolling line on the operator's side near the take-up reel and is designed to transport rolls from the inlet roll rack to the inlet take-up reel.
A movable deck plate is provided to cover the open pit when the bale cart is under the drum mandrel. It will be attached to the carriage and move on it.
It will consist of a carriage, a lifting device, a movable deck plate and a pipeline.
Technical data
| Quantity: | one pack |
| Type of: | V-shaped bale take-up hydraulically driven |
| Carriage: | from welded steel structure mounted on four caterpillar wheels through the axle rotated by hydraulics or AC motor. current |
| Lifting device: | Welded steel structure |
| On a hydraulic cylinder located on the carriage | |
| Equipped with V-shaped bale take-up covered with artificial rubber | |
| Hydraulics powered by auxiliary hydraulics | |
| Movable deck plate: | One pack |
| Lubrication: | Manually using a portable grease gun |
1.1.8 Roll entry rack
Description
This roll rack is located on the operator's side at the inlet take-up reel and is designed to receive the roll from the roll cart and store the roll until unloaded.
Technical data
1.2 Description of double roll reversing mill
1.2.1 Mill stand
Description
2-roll mill, one-piece bed, made of cast or sheet steel.
The bed will be connected by a welded steel spacer.
The rolling line will be manually adjusted using a bar or wedge plate shifting system and a wedge clamp driven by a hydraulic cylinder.
Suction hoods are installed on the frame of the mill to collect smoke generated during rolling.
Technical data
1.2.2 Hydraulic swath positioner
Description
A hydraulic roll positioner is provided to control the working gap to reduce the strip thickness and obtain the specified thickness manually.
Working hydraulic cylinders in two sets. The hydraulic mechanisms of the servo valves control the stroke of the hydraulic cylinder.
Mesdoses are installed at the top of the mill bed.
Technical data
1.2.3 Roll assembly
Description
Two working rolls.
Technical data
1) Work roll
Description
The guide at the entrance is designed to feed the upper end of the strip to the rolls of the mill. It will consist of a pressure roller grip and a side guide.
The clamping grip uses an articulated parallelogram. Available with top and bottom rolls and pneumatic cylinder. Extracted through the hatch of the mill bed for roll change and maintenance.
Side guide vertical roller type. Opens and closes with a hydraulic motor for width adjustment. A quick opening/closing mechanism with hydraulic cylinder is also provided.
The exit guide is located on the exit side of the mill stand and is designed to feed the leading edge of the strip onto the deflection rollers.
Anti-skewing protection is also provided to prevent equipment skewing during refilling and strip breaking on the inlet and outlet sides. The bed of the mill is removed through the hatch with a hydraulic cylinder for changing rolls and maintenance.
Technical data
| 1) Inlet guide | |
| Clamping grip | |
| Quantity: | One pack |
| Material: | welded metal structure |
| Drive unit: | up and down on the pneumatic cylinder |
| Side guide | |
| Quantity: | One pack |
| Type of: | vertical roller |
| Drive unit: | Closing/opening with hydraulic motor Quick opening/closing with hydraulic cylinder |
| 2) Outlet guide | |
| Quantity: | One pack |
| Material: | Welded steel structure |
| 3) Anti-skew protection | |
| Quantity: | One pack |
| Material: | Welded steel structure |
1.2.5 Auxiliary equipment of the mill
Description
Racks with a contact thickness gauge are located on the output side for measuring the strip thickness.
A roller with a tubular scraper is located on the input and output sides of the mill stand and the rack with a thickness gauge.
A large number of cooling manifolds are designed to supply cooling oil to the rolls and strip. The work roll cooling manifold is divided into two sections. Spot cooling collectors are also installed on the output side of the lower work roll. They are divided into eight sections.
Technical data
1) Thickness gauge and stand
Specification
1.2.6 Deflecting and pulling rollers at the inlet and outlet
Description
The inlet and outlet deflection rollers are located on the inlet and outlet sides of the rolling mill and are designed to deflect the strip rolling line and guide the leading edge of the strip onto the mandrel of the tension drum at the inlet and outlet.
This equipment consists of a welded metal structure, deflection rollers, filling guide and pull rollers.
Technical data
| 1) Deflection roller | |
| Quantity: | Two sets |
| Type of: | Non-drive hollow roller Mounted on roller bearing with oil mist lubrication |
| Material: | Heat treated Cr steel |
| Size: | 300mm x 550mmd |
| Frame: | Two sets, installed on the mill bed |
| 2) Filling table | |
| Quantity: | Two sets |
| Material: | Welded steel structure |
| 3) Pull roller | |
| Quantity: | Two sets |
| Type of: | Non-drive hollow roller Mounted on roller bearing with manual lubrication |
| Material: | Heat treated Cr steel |
| Size: | 200mm x 550mm |
1.2.7 Piping of the mill
Description
This piping will be supplied for hydraulic fluid for drives or bearings on the stands from the connection points on the side of the interconnecting piping mill to them.
This applies to the following systems:
- mill hydraulic system
- additional hydraulic system
- oil mist lubrication system
- roll cooling system
- air supply control system
Technical data
- Quantity: one lot
4.1.2.8 Roll changer
Description
A work roll changer will be provided for the simultaneous change of upper and lower work rolls.
It will consist of a windrow handling trolley with side movable table, ejector and rail. The trolley is driven by a hydraulic ejector and is equipped with a hydraulic side table.
A work roll changer will be provided for top and bottom roll handling. It is with a grip and consists of a rail and a spacer. Rail for the lower working roll with a hydraulic drive of the wheel-rail type. Managed manually.
Technical data
1) Device for handling work rolls
1.2.9 Work spindle
Description
The work spindle will be located between the mill stand and the main drive of the mill on the drive side of the mill, it transmits torque from the main drive to the two work rolls.
Technical data
- Type: gear
- Shaft: steel
- Coupling: made of forged steel
- Clutch lubrication: grease gun
4.1.2.10 Working drive of the mill
Description
The work drive will be located between the mill stand and the mill drive, it will drive the two work rolls of the rolling stand through this equipment by a drive motor.
Technical data
1.2.11 Mill front curtain
Description
A protective curtain on the side of the mill operator will be installed to prevent splashing of the roll cooler from the side of the rolling stand. Moreover, the protective curtain will improve the efficiency of the exhaust ventilation system.
In case of windrow handling, the shutter will be opened and closed manually.
Technical data
- Quantity: one set
4.1.3 Outlet section equipment
1.3.1 Outlet drum and idler
Description
The drum and the tension drum are located in front of the entrance to the mill and are intended for winding/unwinding the rolled or already rolled strip.
The drum and idler drum will be of the suspended type with a closed drive.
The base plate is a thick plate. It is mounted on lubricated machined guides with replaceable bronze linings.
The head of the drum and tension drum is one drum with four wedge-shaped segments. The drum head has a clamp for the end of the roll with a hydraulic valve. It is unclenched with a rotating hydraulic cylinder mounted on the drive end of the drum mandrel. The mandrel will expand to a nominal diameter of 500 mm.
Technical data
1) Drum
| Quantity: | One pack |
| Roll dimensions | |
| -ex. diameter: | Max. Φ2,000mm |
| -internal diameter: | 1200mm |
| - roll width: | 400 mm |
| Winding and unwinding speed: | max.80 m/min |
| 2) The actual drum | |
| Quantity: | one pack |
| Roll dimensions | |
| -external diameter: | Max. Φ2,000mm |
| -inner diameter: - roll width: |
600mm 400 mm |
| Winding and unwinding speed: Max. roll weight: |
max.80 m/min 5,000 kg |
| Winding direction: | up and down |
| Body and base: Wedge pad: |
Welded mild steel construction Bearing with bushings |
| Mandrel and stem: Length: |
material SCM 440 approx. 550mm |
Technical data
1.3.2 Roll exit trolley
Description
This roll cart is positioned perpendicular to the rolling line on the operator's side near the exit take-up reel and is designed to transport rolls from the roll rack to the take-up reel.
A movable deck plate is provided to cover the open pit when the bale cart is under the take-up drum mandrel. It will be attached to the carriage and move on it.
It will consist of a carriage, a lifting device, a movable deck plate and a pipeline.
Technical data
1.3.3 Roll output rack
Description
This roll rack is located on the operator's side at the inlet of the take-up reel and is designed to receive the roll from the trolley and store the roll for unloading the rolls.
Technical data
1.4 Accessories
1.4.1 Hydraulic system of the mill
Description
This system is installed in the oil sump and is necessary to supply hydraulic oil for balancing the roll, bending the work and intermediate roll, positioning the roll and moving the intermediate roll.
Technical data
| 1) Reservoir | |
| Quantity | one |
| Type of | cubic tank with internal baffle, sloping bottom and filling nozzle |
| Material | welded steel construction (carbon steel) |
| Oil type | hydraulic oil (mineral oil), viscosity according to ISO VG46 |
| Capacity | approx. 800 l |
| 2) Pump | |
| Quantity | two (including one spare) |
| Type of | rotary plunger type |
| Dimensional characteristics | approx. 50 l/min at 250 kgf/cm² per pump |
| 3) Battery | |
| Quantity | two sets |
| Type of | membrane type |
| Capacity | every 10 l |
| 4) Cooler | |
| Quantity | one |
| Type of | |
| 5) Coolant pump | |
| Quantity | one |
| Type of | rotary gear pump |
| Dimensional characteristics | Approx. 20 l/min., 5 kgf/cm² per pump |
| 6) Filter | |
| Quantity | two - vacuum filter one - cooler filter |
| Accessories | pressure switch and level switch |
1.4.1. Auxiliary hydraulic system
Description
This system is installed in the oil cellar and is required to supply hydraulic oil to all hydraulic boosters of the mill and auxiliary equipment.
This system consists of a reservoir, pumps, accumulators, valves and oils.
| 1) Reservoir | |
| Quantity | one |
| Type of | cubic tank with internal baffle, sloping bottom, sight glass and filling port |
| Material | welded steel construction (carbon steel) |
| Oil type | hydraulic oil (mineral oil), viscosity according to ISO VG32 |
| Capacity | approx. 1200 l |
| 2) Pump | |
| Quantity | three (including one spare) |
| Type of | axial piston type |
| Dimensional characteristics | approx. 30 l/min at 140 kgf/cm² per pump |
| 3) Battery | |
| Quantity | four sets |
| Type of | membrane type |
| Capacity | every 140 kgf/cm² per liter |
| 4) Cooler | |
| Quantity | one |
| Type of | shell and tube floating head |
| 5) Filter | |
| Quantity | two - vacuum filter |
| Accessories | pressure switch and level switch |
1.4.3 Valve rack
Description
This valve rack is installed in the technical cellar, oil cellar and on the frame. It is necessary for the compact placement of solenoid valves for hydraulic and pneumatic systems. Some of the solenoid valves will be provided on the corresponding equipment.
Technical data:
1.4.4 Gear lubrication system
Description
This system is installed in the oil cellar, and is necessary to supply lubricating oil to the bearing and gears of the main drive of the mill, the winders and their drive unit.
It consists of a tank, a pump, filters, a heat exchanger, a temperature controller, valves and piping.
Technical data
Accessories:
- filter
- heating with heater
- cooling with a water cooler
- pressure switches, differential pressure switches and float switches
1.4.5 Oil mist lubrication system
Description
This system is required to supply oil mist to lubricate the mill back-up roll bearing and deflector rolls.
It consists of an oil mist generator, a refill valve assembly and a refill pump assembly.
Technical data
1.4.6 Roll cooling system
Description
This system is required to supply cooling oil to the strip and rolls for lubrication and cooling.
It consists of reservoir, irrigation pump, cooler, filter, filter pump, valves and piping.
The cooling oil reservoir is located in the oil cellar and has an inspection window.
Technical data
1.4.7 Suction system
Description
This system is necessary to suck the vapors around the mill with the help of a mill hood and release the steam from the exhaust pipe to the outside.
It consists of a suction fan (exhauster), a cleaner, a fire damper, pipes and an outlet pipe.
A fire damper must be provided in the intake pipe of the suction fan. It is controlled by a pneumatic cylinder. The work signal is given by the fire detection system and the fire safety system.
Technical data
1.4.8 Drain pump
Description
This system is installed on the drain (drain hole) in the oil cellar and from the purifier to the wastewater treatment plant.
The drainage pump system consists of a pump, valves and accessories.
Technical data
1.4.9 Special tools
Description
A batch of special tools will be provided for equipment maintenance.
A detailed list of tools will be specified at the design stage.
Technical data
1.4.10 Anchor bolts, nuts and washers
Description
A batch of anchor bolts, nuts, washers and gaskets will be supplied to install the mill equipment.
Technical data
Accessories
- anchor bolt, nut and washer
- anchor plate for inserted bolts
- Gaskets and linings for terminal equipment and mill equipment
1.4.11 Connecting pipeline
Description
The supplier supplies the schematic diagram and assembly drawings as the main design decision.
Technical data
1) Hydraulic system
- pumping station ~ valve stand
- valve stand ~ plant piping
2) Lubrication system
- tank ~ pumping station
- pumping unit ~ filter or cooler
3) Roll cooling system
- mill ~ sump
- sump or filtered liquid tank ~ pump
- pump ~ filter or cooler
- filter or cooler ~ plant piping
2 Electrical equipment
2.1 Power supply equipment
Description
The power of the transformer will be determined at the stage of detailed study
1) Pneumatic circuit breaker and switchboard
Type: floor-mounted and self-supporting, indoor
Retractable type for input
Pneumatic circuit breaker of fixed type
For magnetic switch feeder
2) Engine control center
Double-sided pull-out type
soft start for hydraulic motors
Main circuit voltage: 380 V AC current, 3 phases, 50 Hz
Control circuit voltage: 220VAC current, 1 phase, 50 Hz
2.2 Motors and drive console
2.2.1 AC motors
AC constant speed motors are industrial induction motors.
The following technical specifications apply to all unregulated AC motors unless otherwise noted in the motor list.
| 1) Phase | 3 phase |
| 2) Rated voltage | 380V |
| 3) Frequency | 50 Hz |
| 4) Service factor | 1.0 when upgraded to class F |
| 5) Power factor | 100% at constant load |
| 6) Enclosure protection class | IP44 |
| 7) Insulation class | B or F |
| 8) Temperature | Max. 90C at 100% load at 40C ambient |
| 9) Cooling | air-cooled by fan |
| 10) Thermal protection | No |
| 11) Bearing type | rolling / anti-friction, grease lubricated |
| 12) Installation: | on legs / horizontal | 100% constant |
| 14) efficiency | standard |
2.2.2 AC gear motor
The motor transmission is an industrial gearbox. The following technical specifications apply to all gear motors unless otherwise noted in the motor list.
Engine
- The specification is the same as for the unregulated motor
Broadcast
- Bearing type: anti-friction with seals
- Lubrication: grease or splash
- Mounting: foot-mounted / horizontal
- Connection type: straight coupling
- Operational coefficient : AGMA CLASS II (1.4 Based on engine rating)
2.2.3 DC motor with constant power
DC motors are induction motors for industrial applications. The following technical specifications apply to all AC motors unless otherwise noted in the motor list.
1. Phase: 3 phase
2. Rated voltage: 380V DC (set according to the main project)
3. Power factor: 125% 1 minute
4. Enclosure protection class: IP 22, IP54
5. Insulation class: F
6. Cooling: forced or self-cooling fan
7. Accessories: base, anchor bolts, nuts and sleeve/sleeve for motor
8. Efficiency: standard
9. Speed detector (pulse generator if closed loop control)
10. Clutch for speed detector
11. Brake (according to the project)
2.2.5 Constant power DC motor and drive control
2.3 PLC system
Description
A Programmable Logic Control (PLC) system will be supplied to control the cold mill and auxiliary equipment. It will control the gearbox and cold mill auxiliary equipment using a desktop and a human-machine interface (HMI).
The connection of the cold mill to the main PLC will be determined at the detailed design stage.
Technical data
| PLC panel | one piece |
| Type of | indoors (in a metal casing, stable) |
| CPU | advanced command set including file handling, sequencing, control command diagnostic program |
| digital input/output module analog input/output module power module PLC application S/W |
|
| 2) Programmable bootloader | one party |
| Type of monitor size HDD |
a laptop 14 " |
| RAM Accessories |
one piece |
| 3) Printer | one party |
| Type of | color laser printing A4 size or equivalent |
Mill functions
- Push forward or backward; speed signal is adjustable by software, signal range is individual.
- Spindle positioning
Generates a low speed signal for the cage with the same range as the kick.
The positioning stop for the spindle is provided by a proximity switch. - drive control
The required interlocks are sent to the drive. - Speed ratio
The coefficient of linear winding speed of the drum and the circumferential speed of the work rolls are measured by means of pulse generators installed on the deflecting rollers and stand.
The coefficient represents the squeezing (decrease) for the winding (unwinding) drum; it is used in the calculation of initial speed and tension and in inertial control on the right drum or control of the left drum.
Drum Functions
This function - when selecting "reel" (drum): the calculation of tension and speed is automatic.
Push
Push forward or backward; the speed reference signal is adjustable by software, the calculated speed is individual.
Clamp positioning
Generates a low speed drum reference at the same speed as the kick. The stop position for clamping is provided by a proximity switch.
Strip end positioning (only for unwinder)
Generates a low-speed signal to position the end of the strip near the cradle. The positioning works with the drum encoder and stops when the calculated distance (from mechanical dimensions) is reached.
Drive control
The required interlocks are sent to the drive.
Roll diameter
Measured as the ratio between the linear and angular speed of the drum using pulse generators mounted on the deflecting roller and drum. The value is updated at constant drum rotation angles. In the event of a roll slipping onto the deflector roller, the diameter is limited to an approximate value calculated based on the number of turns on the drum and the thickness of the roll.
Strip length
The strip length is measured using the analog-to-digital converter of the deflector
Angular velocity
From the main mill signal and the actual coil diameter, the expansion/contraction of the drum angular velocity signal is calculated and automatically compensated. The calculated signal increases with the amount of additional speed.
Moment of inertia compensation
Calculated using actual bale acceleration, bale diameter, expansion/contraction, and bale width.
Friction and motor compensation
Loss data is stored in a table depending on the actual angular velocity of the drum.
Drum current
The drum current setpoint is calculated based on the tension preset and the moment of inertia compensation. The reference value is adjusted to compensate for mechanical and electrical losses.
Tension control type “Maximum torque”, i.e. the field always has the maximum possible value, while the current in the winding varies depending on the required tension, speed and diameter of the roll.
Running at maximum torque has the advantage of better power factor and less stress on the motor (details in "Tension Control").
Donbass State Machine-Building Academy
Chair -
Automated metallurgical machines and equipment
EXPLANATORY NOTE
to the course work on the discipline
"Technological lines and complexes of metallurgical shops"
Fulfilled
student of group MO-03-2 A.S. Seledtsov
Work supervisor: E.P. Gribkov
Kramatorsk
abstract
The settlement and explanatory note contains pages, 2 tables, 3 sources, 3 figures.
The main objective of this course work is the choice of a cold rolling shop, a rolling mill and the development of a technological process for the production of a sheet 1400 mm wide and 0.35 mm thick from steel 08kp with a capacity of 800 thousand tons per year.
In the course of the work, cold rolling mills of various designs and capacities (reversible and continuous) were considered.
Continuous mill 2030 of the Novolipetsk Iron and Steel Works was chosen for the production of a given rolled product. A description of his equipment is also given in the settlement and explanatory note.
The graphic part of the course work contains a plan for the location of the equipment of the continuous mill shop and schedules for loading the rolling mill stands.
workshop cold rolling steel productivity
ROLLING MILL. CONTINUOUS PICKLING UNIT. GEAR CAGE. COMPRESSION. THE POWER OF ROLLING. ROLLING POWER. FLYING SCISSORS. WINDER. HOME OF DEFORMATION. ROLLGANG.
Introduction
1 Cold rolling mills
1.2 Continuous mill 1700 Mariupol metallurgical plant named after. Ilyich
2 Continuous mill 2030 Novolipetsk Iron and Steel Works
3 Calculation of power parameters of cold rolling. Mathematical support
4 Determination of technological modes of sheet rolling 0.35×1400
5 Mill performance calculation
Conclusion
Link List
Appendix A - Graphs of the distribution of rolling parameters by passes
Appendix B - Program for calculating the energy-power parameters of the rolling process
Introduction
Most of the steel produced goes through rolling mills and only a small amount through foundries and forges. Therefore, much attention is paid to the development of rolling production.
The course "Technological lines and complexes of metallurgical shops" is a special discipline that forms students' professional knowledge in the field of theory and technology of continuous metallurgical lines and units.
As a result of the course work, the following sections should be completed:
Develop and describe technological processes in general for sections (aggregates) and for individual operations with the study of issues of technology continuity;
To make a choice according to the given productivity and dimensions of the cross-section of the sheet metal of the cold sheet rolling mill, from the existing designs;
Calculate the distribution of reductions along the passes in the stands of the rolling mill;
Perform calculations of the rolling forces in each stand of the rolling mill and the power of the electric drives;
Determine the annual productivity of the mill;
Perform automation of technological modes of compression.
In the course of the course work, the knowledge gained during the study of the course "TLKMC" is consolidated and expanded, skills appear in the choice of production equipment, calculations of technological modes of reductions and energy-power parameters of rolling, the use of electronic computers in calculations.
1 Cold rolling mills
The cold rolling method produces strips, sheets and strips of the smallest thickness and up to 4600...5000 mm wide.
The main parameters of broad strip mills is the barrel length of the working stand (in continuous mills of the last stand).
For the production of cold-rolled steel sheets, reversible single-stand and consecutive multi-stand mills are used.
According to the assignment, 3 camps are the most suitable:
1.1 Continuous mill 2500 of the Magnitogorsk Iron and Steel Works
The workshop was put into operation in 1968. The mill equipment is located in seven spans (Figure 1).
Figure 1. Scheme of the main technological equipment of the mill 2500 of the Magnitogorsk Iron and Steel Works:
I - aisle of a warehouse for hot-rolled coils, II - aisle of NTA, III - aisle of a mill, IV - aisle of bell-type furnaces; 1 - transfer conveyor for hot-rolled coils, 2 - overhead cranes, 3 - continuous pickling units, 4 - cross-cutting unit for hot-rolled coils, 5 - working line of the mill, 6 - temper mill, 7 - skin temper mill 1700, 8 and 9 - longitudinal units and cross cutting, 10 - bell furnaces.
The mill is designed for cold rolling of strips with a cross section of (0.6-2.5) x (1250-2350) mm in 30-ton coil with an inner diameter of 800 mm, an outer 1950 mm from steels 08Yu, 08kp, 08ps (GOST 9045 -80), steels 08 - 25 of all degrees of deoxidation with a chemical composition according to GOST 1050-74 and St0 - St3 boiling, semi-calm and calm (GOST 380-71).
1.2 Continuous mill 1700 Mariupol metallurgical plant named after. Ilyich
The first stage of the cold rolling shop was put into operation in 1963, the mill equipment is located in 12 bays (Figure 2).
Figure 2. Layout of the main technological equipment of the cold rolling mill 1700 of the Mariupol Metallurgical Plant named after. Ilyich:
I - storage of hot-rolled coils, II - span of the mill, III - machine room, IV - span of gas bell-type furnaces, V - warehouse of finished products; 1, 3, 8, 10, 12, 13, 19, 20, 22, 24, 26, 28 - overhead cranes, 2 - cross-cutting unit, 4 - transfer conveyors with tilters, c5 - pack packing units, 6 - scissors , 7 - continuous pickling units (NTA), 9 - combined cutting unit, 11 - guillotine shears, 14 - conveyor for supplying rolls to the mill, 15 - decoiler, 16 - working line of the mills, 17 - winder, 18 - outfeed conveyor, 21 - one-stop bell-type ovens, 23 - baling tables, 25 - scales, 27 - skin-passing units, 29 - skin-passing stands, 30 - slitting unit, 31 - roll packing units, 32 - two-stop bell-type furnaces, 33 - baling press
The mill is designed for cold rolling of strips with a cross section of (0.4-2.0) x (700-1500) mm in coils of carbon steel of ordinary quality (boiling, calm, semi-quiet): St1, St2, St3, St4, St5; carbon quality structural: 08kp, 08ps, 10kp, 10ps, 10, 15kp, 15ps, 15, 20kp, 20ps, 20, 25, 30, 35, 40, 45; ageless 08Yu, 08Fkp; electrical steel.
Boiling and calm steels are supplied in accordance with GOST: 16523-70, 9045-70, 3560-73, 17715-72, 14918-69, 19851-74 and specifications with chemical composition in accordance with GOST 380-71 and 1050-74. Electrical steel is supplied in accordance with GOST 210142-75. [ 2 ]
2 Continuous mill 2030 Novolipetsk Iron and Steel Works
Of the considered mills, the Continuous Mill 2030 is the most suitable.
Continuous five-stand cold rolling mill 2030 is designed for rolling strips with a thickness of 0.35-2.0 mm in endless mode and 0.35-3.5 mm in coiled carbon and structural steels. At the mill there are: a warehouse for hot-rolled coils, a pickling department, a section for finishing hot-rolled products, a thermal department and sections for finishing cold-rolled sheets and coatings (Figure 3).
Figure 3. Scheme of the main technological equipment of the cold rolling mill 2030 of the Novolipetsk Iron and Steel Works:
1 - temper mills 2030; 2 - mill line 2030; 3 - strip cutting unit; 4 - guillotine shears; 5 - scales; 6 - overhead cranes; 7 - transfer cart; 8 - continuous pickling units.
Preparation of metal for rolling
The billet for rolling are hot-rolled pickled strips in coils coming from the hot rolling mill 2000. Strip thickness 1.8-6.0 mm, width 900-1850 mm.
Two continuous pickling units are installed in the workshop to remove scale from the surface of hot-rolled carbon steel strips rolled into a coil by mechanical breaking and chemical dissolution in hydrochloric acid solutions.
The main dimensions of the unit are: width 12 m, height 10.95 m, length 323 m, depth 9.6 m. and also installation of regeneration of solutions.
Hot-rolled coils are fed by an overhead crane in a vertical position to the transportation device, turned over to a horizontal position and delivered to the receiving part of the decoiler.
The bale conveyor includes: 49.2 m long walking beam conveyor for 14 bales, width gauge, 440 kN capacity tilter, 3 bale walking beam conveyor, strap removal machine, loading chain conveyor for 5 bales total 19.4 m long (conveying speed 9 m/min), hydraulic installation to supply coil transport devices with hydraulic oil at a pressure of 14 MPa.
The entrance part is designed for unwinding rolls, trimming the front and rear ends, cutting out defects, butt-welding the strips to obtain a continuous strip before pickling. The loading trolley has a lifting drive from two hydraulic cylinders 280/160 and 1200 mm, a travel drive - from a 12 kW DC motor.
Cantilevered four-stage decoiler is designed for coil placement, pickling line axis centering and strip unwinding from above. The front end bender of the strip, pulling and straightening unit serve to feed the front end of the strip from the uncoiler to the guillotine shears, straighten the strip and after cutting the feed to the welding machine. The thickness of the metal cut on the scissors is 6.0 mm, the width is 1950 mm, the maximum cutting force is 625 MN, the stroke of the movable knife is 100 mm.
Type of butt welding machine SBS 80/1600/19N with a welding transformer with a power of 1.6 MW, upsetting force of 780 kN at a pressure of 10 MPa. The maximum width of the strip to be welded is 1.9 m.
A set of tension rollers is used to unwind the strip from the unwinders after welding and to create strip tension in the loop device (four rollers with a diameter of 1.3 m, a barrel length of 2.1 m, three rollers have a diameter of 254 mm, a length of 600 m). The rollers are lined with polyurethane.
The input loop device is designed to create a reserve of the strip, which ensures continuous operation of the unit when moving from one unwinder to another, as well as preparation, welding of the ends of the strips and processing of the weld. Horizontal loops (6 branches) are located under the pickling baths. The lower part of the hinge is supported by roller conveyors, while the upper part is supported by a trolley and rollers of rotary devices. There are three loop trolleys and guide rollers. Strip stock 720 mm, trolley speed 130 m/min, tension created by loop trolley drives 45.8-84.0 KN. The drive of the loop device from two engines with a power of 0-530/530 kW, the number of revolutions is 0-750/775 per minute.
The auxiliary winch is used for filling the strip and bringing the ends together in the event of a break. The stretch straightening machine is designed for preliminary mechanical removal of scale from the strip and creating the necessary flatness. Number of rollers - four, diameter 1.3 m, barrel length 2.1 m, hardness of 15 mm polyurethane coating HSh 95 ± 3 units. The number of working rolls is three, the maximum diameter is 76 mm, the minimum diameter is 67 mm. In one cassette along axis I - 12 support rollers with a maximum diameter of 134.5 mm, a minimum diameter of 125.5 mm, a width of 120 mm, along axis II - 11 rollers with a width of 120 mm and two with a width of 30 mm. During the operation of the units of the pulling and straightening rollers, the welding machine and the stretch straightening machine, scale, dust and metal particles are sucked out by the air flow through the bag filters downwards and are fed into the boxes installed nearby with the help of an auger.
The acid bath consists of five sections with a total length of 133.275 m, a width of 2.5 m and a depth of 0.9 m. Outside the bath there are stiffening ribs made of profile steel, inside there is a 4 mm layer of ebonite, the walls are lined with acid-resistant bricks and fused basalt tiles. Granite blocks and rubberized pickling solution squeezing rollers with a diameter of 345 mm and a barrel length of 2.3 m are installed between the sections of the bath. Lifting and pressing the rollers - from 12 pneumatic cylinders. For metal etching, technical synthetic 32% hydrochloric acid is used. The composition of the pickling solution is 200 g/l of total acid. The amount of circulating solution - 250 m 3 .
The maximum speed of the strip, m/min: in the input part 780, in the pickling 360, and in the output 500. Filling speed 60 m/min. When pickling a 25-ton roll of strip with a cross section of 2.3 x 1350 mm, the average productivity of the pickling unit is 360 t/h.
The continuous pickling unit No. 2 is similar in composition and equipment characteristics to the continuous pickling unit No. 1. It additionally includes a passivation section 5.0 m long for applying a solution that protects the metal from corrosion.
The composition of the passivating solution, kg / m 3: 42 soda (NaCO 3), 42 trisodium phosphate (Na 3 P0 4), 42 borax (Na 2 S 2 O 3).
On the outlet side of the pickling bath there is a double set of control wringer rollers.
The washing bath is designed as a five-stage cascade washing and consists of five sections with a total length of 23.7 m.
The outlet part of the pickling unit is equipped with two tension rollers with a diameter of 1300 mm, a barrel length of 2100 mm and two pressure rollers with a diameter of 254 mm and a barrel length of 800 mm. The loop device at the exit is designed to form a stock strip (450 m). Horizontal loops (four branches) are located under the pickling baths. The lower part of the hinge is supported by roller conveyors, while the upper part is supported by a trolley and rollers of rotary devices. There are two stretch carts. The tension created by the loop trolley drives is 45-68 kN.
Tension roller set No. 3 is designed to form strip tension at speeds< 60 м/мин.
The side edges on the etched strip are cut with a circular shear. The unit is equipped with two circular shears, during the operation of one, the others are adjusted, which reduces the time for replacing and tilting the knives. Knife diameter before regrinding 400 mm, after 360 mm, knife thickness before regrinding 40 mm, after 20 mm. There are four knives in the installation. The maximum width of the cut edge on one side is 35 mm, the minimum is 10 mm. The scissors are made in the form of broaching ones, i.e. with non-driven knife shafts. In the unit - two edging scissors. To tension 10.8-108 kN of the strip, tension and pressure rollers are installed in front of the winder.
The oiling machine is designed to lubricate the strip with anti-corrosion protective oil or an emulsion of 12 spray nozzles, applied directly or through a felt roller, depending on the speed and width. Excess oil is squeezed out by a pair of rubberized rollers with a diameter of 200 mm, a barrel length of 2.1 m.
The technical characteristics of mechanical shears for transverse cutting of welded seams, cutting samples and cleaning device from them are similar to shears for transverse cutting of the inlet part.
After cutting, the strip is fed into the drum of a floating type winder with an electro-hydraulic follow-up system using sets of deflecting rollers No. 1 and No. 2. The coilers are driven by a 0-810/810-kW motor (10-450/1350 rpm). The maximum allowable roll weight is 45 tons, strip tension is 105 kN.
From the winder drum, the rolls are transferred by a stripper to a humpback chain conveyor, consisting of a transfer trolley and a removable fork, and by a transportation device - to the storage of pickled rolls. The transport device consists of a 40-m unloading double-chain conveyor for 11 rolls, a trough walking beam for three rolls, a 14-m humpback walking beam for four rolls and a 185-m double-chain conveyor for 26 rolls. Conveying speed 9-12.5 m/min.
At the warehouse, rolls are marked, tied with one or two metal tapes, weighed on a 50-ton scale with a photoelectric sensing device and a remote printer. The continuous pickling line is automated. As a result of automation with the use of UVM, the mechanisms of the unit of the input, central and output parts are controlled, the sequence of operations for transporting strips, the selection and control of the technological mode of processing the strip, tracking the material from the moment the roll is fed to the decoiler and until marking it with data transfer to the UVM of the mill by machine connection. [ one ]
3 Calculation of power parameters of cold rolling. Mathematical support
Optimization of technological regimes of reductions during cold rolling of strips, sheets and strips is one of the most important factors that ensure the improvement of the technical and economic indicators of the rolling production process as a whole. At the same time, the importance of the optimal technological modes of reduction and the corresponding energy-power parameters of the rolling process is necessary from the point of view of increasing the scientific validity of design solutions used both in the creation of new and in the modernization of existing rolling mills.
Mathematical models of the cold rolling process, organized to fulfill the criteria for the full load of mechanical equipment, were used directly as target functions in optimizing the technological modes of reduction.
The software for solving the set optimization problem was implemented on the basis of the algorithmic method of purposeful enumeration of options. An analytical description of this method can be represented as:
where is the value of the absolute compression of the strip in the i-th pass;
Sequence number of the next cycle of the iterative solution procedure;
The step of changing the value of absolute reduction, the quantitative assessment of which was taken as a variable depending on the degree of application of intermediate results to the original one;
The given values of the parameters , , directly related to the accepted optimality criterion;
Considering the above and based on the logic of functional relationships between the magnitude of the absolute reduction and the energy-power parameters of the hot rolling process, the solution of the optimization problem under the condition of the full load of mechanical equipment can be represented as successive step-by-step increments:
in case of simultaneous fulfillment of each of the conditions: , , .
If at least one of these conditions is not met, we change the value of the step increment:
where is the initial thickness of the sheet in this pass.
Thus, the absolute reduction can be determined, corresponding to the condition for ensuring the maximum allowable load and, as a result, the condition for achieving the maximum performance of the mechanical equipment of specific rolling mills.[ 4 ]
4 Determination of technological modes of sheet rolling 0.35×1400
We choose as a blank for the production of a sheet 0.35 × 1400 (material - steel 08kp) a strip 1.8 mm thick, 1400 mm wide and 1500 mm long.
Let us determine the energy-power parameters of rolling in the roughing stand. We will carry out the calculation according to the engineering method.
Initial roll thickness h 0 =1.319mm, absolute reduction ∆h=0.939mm, rolled width 1400mm, roll radius R=300mm, rolling speed 43.8 m/s.
regression coefficients;
Double shear strength: MPa.
Because there are no front and rear tensions, then ξ 0 =ξ 1 =1
d=2f l / Dh= 2∙0.09∙4.54/0.069=11.84
p SR \u003d n s 2K C \u003d 0.043 ∙ 610 \u003d 26.72 MPa
N = M w = M V / R=85.3∙43.8/0.3=0.932 kW
With the selected rolling mode, the energy and power parameters in the stand do not exceed the limit values.
Further calculation is carried out on a computer. The calculation results are shown in Table 4.1.
Table 4.1 - The results of the calculation of energy-power parameters.
| pass number | |||||||||
| 1 | 1.8 | 1.8 | 1.319 | 0.267 | 463 | 9.99 | 138.8 | 1.11 | 2 |
| 2 | 1.8 | 1.319 | 1.125 | 0.147 | 610 | 9.98 | 85.3 | 0.932 | 2.73 |
| 3 | 1.8 | 1.125 | 0.993 | 0.117 | 657 | 9.99 | 70.1 | 0.897 | 3.2 |
| 4 | 1.8 | 0.993 | 0.894 | 0.100 | 687 | 9.98 | 60.5 | 0.877 | 3.62 |
| 5 | 1.8 | 0.894 | 0.815 | 0.088 | 707 | 9.98 | 53.7 | 0.865 | 4.03 |
Table 4.2 - The results of the calculation of energy-power parameters.
| pass number | |||||||||
| 1 | 0.81 | 0.815 | 0.558 | 0.315 | 489 | 11.98 | 136.7 | 1.094 | 2 |
| 2 | 0.81 | 0.558 | 0.470 | 0.128 | 642 | 11.97 | 76 | 0.888 | 2.92 |
| 3 | 0.81 | 0.470 | 0.413 | 0.121 | 682 | 11.94 | 60.1 | 0.833 | 3.47 |
| 4 | 0.81 | 0.413 | 0.372 | 0.1 | 706 | 11.91 | 50.5 | 0.797 | 3.95 |
| 5 | 0.81 | 0.372 | 0.350 | 0.058 | 716 | 9.94 | 29.2 | 0.513 | 4.38 |
Energy and power parameters do not exceed the allowable values in the stands. Therefore, this mill loading mode is the most optimal and rational. [ 4 ]
5 Mill performance calculation
Hourly productivity of the mill:
where is the rhythm rolling,
Acceleration and deceleration of the ingot, 
speed in the last stand,
seeding speed,
initial length of the ingot,
initial ingot thickness,
final ingot thickness,
final bandwidth,
- the mass of the tackle,.
The rolling rhythm T is determined by the formula:
,
where t m is the machine time of rolling in the i-th pass;
t p - pause time, t p \u003d 14 s;
Substitute the value:
Let's define the annual productivity:
,
where T cf = 7100 - the average number of working hours of the mill per year;
K g \u003d 0.85 - the coefficient of yield of suitable rolled products.
According to the calculated annual productivity, it can be concluded that the mill will provide the specified productivity.
To achieve high quality rolling of thin sheets, it is necessary to ensure quality control, from steelmaking to finishing operations after cold rolling.
The main issues are to increase the yield of suitable rolled products, which can be achieved by using a number of technological operations: reducing the longitudinal and transverse thickness variation and non-flatness of the sheet (corrugation, crescent, waviness), using active reduction control systems, profile control systems, the use of a straightening machine, i.e. d.
Conclusion
In the course of the course work, various equipment for cold rolling of sheets was considered. At the same time, the most rational for the production of sheets 0.35 × 1400 is the use of the Continuous Mill 2030.
Automated optimization of technological modes of reductions was performed, as well as energy-power parameters were calculated. According to the results of these calculations, it can be concluded that the mill is loaded optimally. This is a consequence of the correct choice of compression modes.
The calculation of the mill productivity shows that the selected mode of operation of the mill provides a given productivity of 0.8 million tons/year.
Link List
1. "Modern development of rolling mills". Tselikov A.I., Zyuzin V.I. – M.: Metallurgy. 1972. - 399 p.
2. "Mechanical equipment of rolling shops of ferrous and non-ferrous metallurgy". Korolev A.A. – M.: Metallurgy. 1976. - 543 p.
3. Machines and units of metallurgical plants. In 3 volumes. T.3. Machines and units for the production and finishing of rolled products. Textbook for universities / Tselikov A.I., Polukhin P.I., Grebennik V.M. and others. 2nd ed., revised. and additional - M.: Metallurgy, 1988. - 680 p.
4. Bulatov S.I. Methods of algorithmization of rolling production processes. - M.: Metallurgy, 1979. - 192 p. (Ser. "Automation and metallurgy").
5. Vasilev Ya.D. Production of strip and sheet steel: Educational metallurgist, universities and faculties. - Kyiv: Vishcha. school, 1976. - 191 p.
6. Vishnevskaya T.A., Libert V.F., Popov D.I. Improving the efficiency of sheet mills. - M.: Metallurgy, 1981. - 75 p.
7. Diomidov V.V., Litovchenko N.V. Technology of rolling production: Proc. allowance for universities. - M.: Metallurgy, 1979. -488 p.
10. Zaitsev B.C. Fundamentals of technological design of rolling shops: Proc. for universities. - M.: Metallurgy, 1987. - 336 p.
11. Konovalov SV, Ostapenko A.L., Ponomarev V.I. Calculation of sheet rolling parameters: Handbook. - M.: Metallurgy, 1986. - 429 p.
12. Konovalov SV. etc. Handbook of the distributor. - M.: Metallurgy. 1977. - 311 p.
13. Controlled rolling / V.I. Pogorzhelsky, D.A. Litvinenko. Yu. I. Matrosov, A. V. Ivanitsky. - M.: Metallurgy, 1979. - 183 p.
15. Korolev L. A. Design and calculation of machines and mechanisms of rolling mills: Proc. allowance for universities. - 2nd ed., revised. and additional -M.: Metallurgy, 1985. - 376 p.
16. Tape rolling mills and dressing equipment: Catalogue. -M.: TsNIITEItyazhmash, 1980. - 81 p.
17. Litovchenko N.V. Mills and technology for rolling sheet steel. - M.: Metallurgy, 1979. - 271 p.
18. Mazur V.D., Dobronravov A.I., Chernov P.I. Prevention of sheet metal defects. - Kyiv: Techn1ka, 1986. - 141 p.
– Program for calculating the energy-power parameters of the rolling process
"Program for calculating the reduction modes on the NSHP
"TLKMC coursework
"INPUT "Number of stands in a continuous mill group"; N
"INPUT "a0="; a0: INPUT "a1="; a1: INPUT "a2="; a2: INPUT "a3="; a3
"INPUT "Initial metal thickness in annealed state"; Hh0
"INPUT "Initial metal thickness before pass"; h0
"INPUT "Permissible rolling force value.....(MN) [P]="; Pd: Pd = Pd * 1000000!
"INPUT "Permissible rolling torque (kNm) [M]="; Md: Md = Md * 1000000!
"INPUT "Permissible rolling power value (MW) [N]="; Nd: Nd = Nd * 1000000!
OPEN "cold.txt" FOR OUTPUT AS 1
a0 = 240: a1 = 1130.6: a2 = -1138.9: a3 = 555.6
S0 = .1: S1 = .1
PRINT "RESULTS OF THE CALCULATION OF REDUCTIONS ON THE CONTINUOUS MILL X.PR."
PRINT ────┬───────┐"
PRINT "│i │ H0 │ h0 │ h1 │ e │K2c │ P │ M │ N │ V │ "
PRINT "││ mm │ mm │ mm ││MPa │ MN │ kNm │ MW │ m/s │ "
PRINT " ────┼──────┤"
PRINT #1, "RESULTS OF THE CALCULATION OF REDUCTIONS ON THE CONTINUOUS MILL X.PR."
PRINT #1, " ┬──────┬─────┐"
PRINT #1, "│i │ H0 │ h0 │ h1 │ e │K2c │ P │ M │ N │ V │ "
PRINT #1, "││ mm │ mm │ mm ││MPa │ MN │ kNm │ MW │ m/s │ "
PRINT #1, " ┼──────┼─────┤"
IF h1 > h0 THEN INPUT "h0>h1"; asd$
e0 = (Hh0 - h0) / Hh0
x1 = a0 + a1 * e0 + a2 * e0 ^ 2 + a3 * e0 ^ 3
x2 = 2 / 3 * (a1 + 2 * a2 * e0 + 3 * a3 * e0 ^ 2) * e
x3 = 8 / 15 * (1 - e0) ^ 2 * (a2 + 3 * a3 * e0) * e ^ 2
x4 = 16 / 35 * (1 - e0) ^ 3 * a3 * e ^ 3
K2c = 1.15 * (x1 + x2 + x3 + x4)
ksi0 = 1 - S0: ksi1 = 1 - S1
delta=2*f*L/dh: IF delta=2 THEN delta=2.1
Hn = (ksi0 / ksi1 * h0 ^ (delta - 1) * h1 ^ (delta + 1)) ^ (1 / 2 / delta)
IF Hn = 0 OR h1 = 0 THEN INPUT "h=0"; ads$
y1 = (h0 / Hn)^(delta - 2) - 1
y1 = y1 * ksi0 * h0 / (delta - 2)
y2 = (Hn / h1)^(delta + 2) - 1
y2 = y2 * ksi1 * h1 / (delta + 2)
nG = (y1 + y2) / dh
x2 = 8 * Pcp * R * 2 * (1 - .3^2) / 3.14 / 210000!
Lc = SQR(R * dh + x2 ^ 2) + x2
dL = ABS(Lc - L) / L * 100
LOOP UNTIL dL > 5
M = 2 * K2c * (y1 - y2) * R * f / dh * b * L
IF P > Pd OR M > Md OR Nw > Nd THEN h1 = h1 + .001: GOTO 10
PRINT USING "│##│#.##│#.###│#.###│#.###│####│###.##│####.#│# #.###│##.##│"; i; hh0; h0; h1; e; K2c; P/1000000!; M/1000000; Nw/1000000; V
PRINT #1, USING "│##│#.##│#.###│#.###│#.###│####│###.##│####. #│##.###│##.##│"; i; hh0; h0; h1; e; K2c; P/1000000!; M/1000000; Nw/1000000; V
V = V * h0 / h1: h0 = h1
PRINT ────┴───────┘"
PRINT #1, " ┴──────┴──────┘"