Rolling Mill Production Line

Thursday, June 4, 2020

What Is Continuous Casting Machine?

Continuous casting is the process of continuously casting high-temperature molten steel into billets with certain section shape and size.

The equipment needed to complete this process is called continuous casting complete equipment. The mechanical and electrical hydraulic integration of steel casting equipment, caster body equipment, cutting area equipment, dummy bar collection and conveying equipment constitutes the core equipment of continuous casting steel, which is commonly called continuous caster.

The high-temperature molten steel is continuously poured into one or a group of water-cooled copper crystallizers, and the molten steel gradually solidifies into the shell along the periphery of the crystallizer. When the liquid level of the steel rises to a certain height and the shell solidifies to a certain thickness, the tension leveler will pull out the billet, and the billet will be completely solidified by spray cooling in the secondary cooling area. The cutting device will cut the billet to a certain length according to the rolling requirements. The process of making high-temperature molten steel directly cast into billet is called continuous casting.

Its appearance has fundamentally changed the ingot rolling process, which has been dominant for a century. Because it simplifies the production process, improves the production efficiency and metal yield, and saves energy consumption, the production cost is greatly reduced, and the billet quality is good. At present, in steel-making enterprises, whether it is long process steel-making or short process steel-making, the configuration of continuous casting machine is almost inevitable.

Classification of the continuous casting machine

Continuous casters can be classified in many forms. According to the structure and shape, the caster can be divided into vertical caster, vertical bending caster, arc caster with straight section, arc caster, multi radius elliptical caster and horizontal caster. With the development of continuous casting technology, the research of wheel caster, especially thin slab caster, has been carried out.

According to the size and shape of the section cast by the caster, the caster can be divided into slab caster, billet caster, bloom caster, round billet caster, special section caster and thin slab caster. The rectangular billet caster is also included in the square billet caster. Generally, the billets with casting section or equivalent sectional area greater than 200 × 200 mm are called bloom, the billets with section or equivalent sectional area less than 160 × 160 mm are called billet, and the rectangular billets with width thickness ratio greater than 3 are called slab.

If the continuous casting machine can be divided into single flow, double flow or multi flow continuous casting machines according to the number of billet flow that can be cast under the same ladle.

Composition of continuous caster

Generally, the continuous caster is composed of liquid steel carrier (ladle, rotary table), tundish and its replacement device, mould and its vibration device, secondary cooling area clamping roller and cooling water system, pulling straightener, cutting equipment, dummy bar device, etc.

The tundish plays the role of buffering and purifying the molten steel. The capacity of tundish is generally 20% - 40% of the capacity of ladle. The more the flow number of caster is, the larger its capacity is. The mold is the "heart" of the continuous casting machine, which requires good thermal conductivity, structural rigidity, wear resistance and easy to manufacture and maintain. It is generally made of forged copper or cast brass, and its outer wall is forced to cool evenly by water.

The function of the mould vibration device is to make the mould vibrate periodically, so as to prevent the bonding between the primary shell and the mould wall from being broken. The vibration curve generally changes according to the sinusoidal law to reduce the impact. Its amplitude and frequency should be closely matched with the pulling speed to ensure the quality and output of the slab.

The secondary cooling device is installed at the outlet of the mould, which can accelerate the solidification of the slab and control the temperature of the slab by means of water spray or atomization cooling. The pinch roll and guide roll support the high-temperature billet with liquid core to prevent bulging deformation or internal crack. At the same time, the liquid core reduction technology can be carried out in this section to improve the quality and output of the billet. The water pressure and water volume of the secondary cooling device are required to be adjustable to meet the needs of different steel grades and different pulling speeds.

The function of the straightening machine is to provide the power of drawing billet and straighten the bent billet, and to push the cutting device to move. The speed of drawing billet has a great influence on the output and quality of the continuous casting. The function of the dummy device is to plug the lower mouth of the mould with the dummy head before the start of continuous casting, pull the billet out of the caster after the solidification of the molten steel, then disconnect the dummy head, and put the dummy bar into the storage device.

The billet cutting equipment can cut the continuously moving billet into a fixed length. The commonly used cutting equipment is flame cutter or hydraulic shear and swing shear.

More Articles You May Be Interested In:

1. Technological Features of Continuous Billet Caster

2. What is Continuous Casting and Continuous Rolling?

3. Continuous Rolling, Semi-continuous and Slit Rolling Processes of Rolling Mills

4. What is the difference between horizontal continuous casting and arc continuous casting?

5. How Does Horizontal Continuous Caster Realize Billet Drawing?

6. Why Develop Horizontal Continuous Casting Technology?

7. What’s the Main Equipment of the Horizontal Continuous Casting Mill?

8. Continuous Casting Machine Equipment

Monday, June 1, 2020

How Does Electric Arc Furnace Work?

1. Feeding
The operation of adding raw materials such as molten iron or scrap steel to the electric furnace is the first step of the steelmaking operation of the electric arc furnace.

2. Slagging
Slag making is an operation to adjust the composition, basicity, viscosity and reaction ability of slag in steel and iron production. For example, the purpose of oxygen blowing operation is to generate slag with enough fluidity and basicity, which can transfer enough oxygen to the metal surface, so as to reduce the sulfur and phosphorus below the upper limit of planned steel grade, and minimize the amount of splashing and slag overflowing during oxygen blowing.

3. Slag out
According to different smelting conditions and purposes, the operation of slag discharging or raking is adopted in the process of EAF steelmaking. For example, when smelting with the single slag method, the oxidation slag must be removed at the end of oxidation; when reducing slag is made with the double slag method, the original oxidation slag must be completely discharged to prevent phosphorus return, etc.

4. Pool stirring
Energy is supplied to the molten metal pool to make the molten metal and slag move, so as to improve the dynamic conditions of the metallurgical reaction. Pool stirring can be realized by means of gas, mechanical, electromagnetic induction and other methods.

5. Dephosphorization
Chemical reaction to reduce phosphorus content in molten steel. Phosphorus is one of the harmful impurities in the steel. The steel with more phosphorus is easy to crack when it is used at room temperature or lower, which is called "cold brittleness". The higher the carbon content in steel, the more serious the brittleness caused by phosphorus. Generally, the phosphorus content of ordinary steel is not more than 0.045%, and the phosphorus content of high-quality steel is less.

6. Bottom blowing
N2, Ar, CO2, Co, CH4, O2 and other gases are blown into the molten pool of the furnace through the nozzle at the bottom of the furnace according to the process requirements to accelerate the melting and promote the metallurgical reaction process. The bottom blowing process can shorten the smelting time, reduce the power consumption, improve the dephosphorization and desulfurization operation, increase the amount of residual manganese in the steel, and improve the metal and alloy yield. It can make the composition and temperature of molten steel more uniform, so as to improve the quality of steel, reduce the cost and improve productivity.

7、 Melting period
The melting period of steelmaking is mainly for open-hearth and electric furnace steelmaking. The melting period of EAF steelmaking is from the beginning of power on to the end of the melting of all the trace materials in the furnace, and from the end of molten iron blending to the end of the melting of all the materials in the open hearth steelmaking. The task of the melting period is to melt and heat up the charge as soon as possible, and make the slag in the melting period.

8. Oxidation and decarbonization
The oxidation period of EAF steel-making usually refers to the process stage from the melting and cleaning of furnace burden, sampling and analysis to the completion of slag removal. It is also believed that it starts from blowing oxygen or adding ore to decarbonize. The main tasks of the oxidation period are to oxidize the carbon and phosphorus in the molten steel, to remove the gas and inclusions, and to heat the molten steel uniformly. Decarburization is an important process in the oxidation stage. In order to ensure the purity of steel, the amount of decarburization is required to be more than 0.2%. With the development of off furnace refining technology, the oxidation refining of EAF mostly moves to ladle or refining furnace.

9. Refining period
In the process of steelmaking, some elements and compounds harmful to the quality of steel are selected into the gas phase or discharged or floated into the slag through chemical reaction through slagging and other methods, so that they can be excluded from the molten steel.

10. Reduction period
In the operation of EAF, the period from the end of oxidation to the end of tapping is usually called reduction period. Its main task is to make reducing slag for diffusion, deoxidization, desulfurization, chemical composition control and temperature adjustment. The reduction period has been canceled in high power and superpower EAF steelmaking operations.

11. Off furnace refining
The steelmaking process in which the primary molten steel in a steelmaking furnace (converter, electric furnace, etc.) is transferred to another vessel for refining, also called secondary metallurgy. Therefore, the steelmaking process is divided into two steps: primary refining and refining. Primary smelting: the charge is melted, dephosphorized, decarburized and main alloyed in an oxidizing atmosphere. Refining: degassing, deoxidizing, desulfuration, removal of inclusions and fine-tuning of the composition of primary molten steel in vacuum, inert gas or reducing atmosphere. The advantages of steelmaking in two steps are: improving the quality of steel, shortening the smelting time in steelmaking workshop, simplifying the process and reducing the production cost. There are many kinds of off furnace refining, which can be roughly divided into two categories: off furnace refining under atmospheric pressure and off furnace refining under vacuum. According to the different treatment methods, it can be divided into ladle treatment and ladle refining.

12. Liquid steel mixing
The stirring of molten steel in the refining process outside the furnace. It can homogenize the composition and temperature of molten steel and promote the metallurgical reaction. Most metallurgical reactions are phase interface reactions, and the diffusion rate of reactants and products is the limiting link of these reactions. In the static state, the metallurgical reaction speed of molten steel is very slow, for example, it takes 30-60 minutes to desulfurize the static molten steel in the electric furnace, while it only takes 3-5 minutes to desulfurize the molten steel by stirring the molten steel in the furnace refining. When the molten steel is in static state, the removal rate of inclusions floats upward and is slow; when the molten steel is stirred, the removal rate of inclusions increases exponentially and is related to the stirring strength, type, characteristics and concentration of inclusions.

13. Ladle wire feeding
By feeding deoxidizing, desulfurizing and fine-tuning powder wrapped with iron sheet, such as Ca Si powder, or directly feeding aluminum wire, carbon wire, etc. into the ladle through wire feeder, the method of deep desulfurizing, calcium treatment and fine-tuning of carbon and aluminum in the steel can be carried out. It also has the functions of cleaning molten steel and improving the morphology of non-metallic inclusions.

Friday, May 29, 2020

The Advantages of DC Electric Arc Furnace

Do you know what an electric arc furnace is? In fact, electric arc furnaces come from tools used to make steel. There are many types of electric arc furnaces. Different types of electric arc furnace steelmaking methods are different. A DC electric arc furnace is a steel-making electric arc furnace that is powered by a DC power source. So what are the advantages of DC electric arc furnace? Today I will introduce the advantages of DC electric arc furnace.

It is the same as AC electric arc furnace, which uses the arc generated between the electrode and the charge (or molten pool) to generate heat, so as to achieve the purpose of melting, and can be used to melt steel or alloy.

Compared with the traditional AC electric arc furnace, the main advantages of the DC arc furnace are:

(1) The arc is stable and concentrated, the molten pool is well stirred, the temperature distribution in the furnace is uniform, and the erosion of the furnace lining is small;

(2) The current and voltage fluctuations are small, the impact on the power grid is reduced, and the cable life is extended accordingly;

(3) Less electrode loss, 50% less electrode consumption per ton of steel than AC arc furnace. The performance of the DC arc furnace is better than that of the AC arc furnace, but it has been suffering from the failure to obtain a high-power DC power supply, which has prevented it from developing for a long time.

With the application of thyristor technology, the manufacturing technology of high-power DC power supply equipment has been solved, so in the late 1970s, the metallurgical industry re-launched the research of DC arc furnaces, and the technical problems of construction and use of DC arc furnaces in the early 1980s have been solved one by one. The world's first DC electric arc furnace was built and put into production at the Bush Steel Plant in Germany in 1982. In the next six or seven years, the United States, France, Italy, Japan and other countries have successively rebuilt or built their own DC electric arc furnaces from 30t to 60t.

In 1989, Tokyo Steel Corporation of Japan built the largest DC arc furnace with a capacity of 130 tons. In recent years, many DC arc furnaces have been built and put into production in various countries around the world, with capacities ranging from 60t to 180t. In 1989, China Taiyuan Machinery Foundry developed China's first small DC electric arc furnace and put it into production. In the same year, a 2000kVA submerged arc DC electric arc furnace in Xuanhua Ferroalloy Plant was put into production, used to produce ferrosilicon, ferromanganese, calcium silicon and other ferroalloys. Since the beginning of the 1990s, DC arc furnaces have received more and more attention. Shanghai No. 3 Steel Plant, Great Wall Steel Plant, Qiqihar Steel Plant, Jiangyin Yanshan Steel Plant, Shanghai No. 1 Steel Plant have introduced large-scale DC arc furnaces with a capacity of 80 ~ 100t. Baoshan Iron and Steel (Group) Company introduced a set of 150t DC electric arc furnace equipment with double furnace shells (one power supply) from France.

There is only one electrode above the DC electric arc furnace, which is the negative electrode and the bottom electrode is the positive electrode. Its power supply system is different from that of AC arc furnace. It is equipped with rectifier and reactor. A contact is installed on the furnace bottom to form a current circuit. The maintenance and service life of the contact are the key problems in the operation of the DC arc furnace. Generally, the copper plate is placed on the furnace bottom steel plate to facilitate conduction. Three layers of magnesia carbon bricks are built on the copper plate, and then refractory materials are knotted on it.

Tuesday, May 26, 2020

The Effective Ways to Reduce Roll Consumption

1. Overview

The roller directly contacts the strip rolled product, which is an important tool for hot rolling production. Reducing roller consumption can effectively reduce production costs and increase benefits. At the same time, it can effectively improve the operation rate of the rolling mill and ensure the surface quality of hot rolled products. In the production of hot-rolled strip steel, the consumption of rolls is particularly huge. Therefore, it is of great significance to find out measures to reduce the roll consumption and increase the life of the rolls.

2. Optimize the roll change period

2.1 Rough rolling work roll
The original rough rolling roll changing period is 2.5wt ～ 3.8wt, on this basis, gradually extend the roll changing period, and compare the roll wear, strip shape and surface quality. The roll changing period is now stable at 3.8wt ~ 4.5wt. It does not affect the shape and surface quality of the strip, and extends the service life of the roll.

2.2 Back-up roll of finishing rolling mill
The rotation speed of F1-F7 roll is different and the difference is large, so the wear degree of back-up roll is also different. The one-cut roll change period that originally used 10wt-15wt is unreasonable, and the segmented roll change is now used.

Since the adoption of sectional roll change, not only the rolling capacity of the roll has been increased by about 14.94%. Moreover, according to the statistical data, the wave shape of the roller when rolling the thin gauge at the end of use is also reduced.

3. Correct treatment method of rolling accident

Serious rolling accident directly increases the numerical value of roll consumption, and whether the accident roll can be handled correctly after the accident is the key to reduce the roll consumption.

3.1 Stuck steel accident
In case of steel jamming, the cooling water shall be stopped immediately and the upper roll shall be lifted to avoid the upper roll contacting the strip steel; after the strip steel is removed, the roll shall be changed and cooled slowly. If the roll cannot be changed immediately and the crack is not serious, the working roll can enter into normal rolling only after the cooling water is not opened and idling for 5-10 minutes to make the temperature spread evenly.

3.2 Steel sticking accident
First remove the sticking steel. After that, the steel sticking area shall be inspected in detail, including hardness, crack, flaw detection, etc. the affected area of steel sticking must be removed to ensure that the hardness of the roll surface is uniform and free of crack.

4. Treatment method of common accident roll:

4.1 Hot cracks
Most of the hot cracks are caused by the cold and exciting heat of the roll after the accident of steel jamming or steel piling.

Treatment method: R1 and F1-F4 rolls can be rolled with hot cracks on the premise of ensuring smooth rolling, and the cracks are closed (closed cracks do not extend, but with the use of time), and the cracks will be gradually eliminated.

4.2 Roll bonding
Steel sticking on the roll, tail flicking or steel piling accidents cause the steel sticking on the roll.

Treatment method: when the thickness of the roll is more than 3mm, the adhered strip needs to be turned off first. Check the surface of the roll body after the attached sheet metal is removed. If there is any crack or peeling (peeling off), the cutting depth shall be determined according to the damage degree, so as to eliminate the defect without increasing the roll consumption.

4.3 Edge peeling of working roll
The edge of the working roll is peeling off, and the stress concentration of the shoulder of the roll is caused.

Treatment method: because the shoulder of the roll does not contact the steel plate directly, the part of the crack peeling off can be removed, the chamfer can be grinded, and the chamfer way and angle of the contact supporting roll can be adjusted to improve the stress distribution of the roll body.

4.4 Back up roll defects

The back-up roll is not in direct contact with the strip steel and its hardness is lower than that of the working roll, but its price is expensive, so it is not suitable to adopt the conventional grinding method.

Treatment method: when the damage is at the edge of the roller, increase the length of the end chamfer properly during grinding. The residual defects shall be treated with an angle grinder and the periphery shall be too smooth to prevent further spread of peeling defects. When the damage is in the middle of the roller, it should be grinded as usual and then treated with an angle grinder to make the defect too smooth.

5. Adjustment of roll shape

According to the actual production situation, the F1-F4 roll is changed from concave roll to HVC roll. Moreover, the negative crown of f5-f7 roll is increased to improve the stress distribution on the roll surface. The utility model can achieve the purpose of better controlling the plate shape and reducing roller consumption.

6. Other ways to reduce roll consumption

① Organize to drill the treatment methods of various rolling accidents, improve the emergency response speed, and minimize the damage to the roll caused by the accident;

② Set up reasonable detection standard of roller to ensure the quality of roller and reduce unnecessary loss;

③ Select excellent roll manufacturers, and customize high-quality rolls with materials and hardness in line with the production characteristics of Chongqing Iron and Steel Co., Ltd;

④ After the production is stable, the high-speed steel roll is selected for the working roll in the front section of finishing rolling to further reduce the roll consumption.

7. Conclusion

① The adjusted HVC profile and negative crown roll not only improve the stress distribution on the roll surface, but also strengthen the crown control ability of the strip steel, which is conducive to the guarantee of product quality.

② Adjusting the roll changing period, responding to the rolling accident and correctly handling the accident roll can ensure the product quality, increase the rolling amount of a single roll and extend the service life of the roll.

③ The treatment measures for the accident roll reduce the unnecessary grinding of the roll, thus reducing the labor intensity of the staff.

Monday, May 18, 2020

30, 000 Ton Tpy Wire Rod Mill Production Line

The finished product of this production line is hot rolled 5.5 wire rod. The main technological process is: 70 × 70 square continuous casting billet smelted by intermediate frequency furnace and continuous casting machine is sent to the full continuous rolling unit through the conveying roller table to be directly rolled into shape; then after pressure feeding, spinning and cooling, it is rolled by the turning machine and push the small coil to the winder. N small rolls are merged and bundled into a large roll on the winder; then list, weigh, and store.

Parameters:
1. Designing one production line of 6tons/hour

2. Raw materials: steel scrap
3. Produced billet size:70*70*2300mm
4. Finished product: 5.5wire rod
5. Total power consumption:8700kw

Process flow:

Intermediate Frequency Furnace Smelting——Continuous Casting Mold——Rough Rolling Unit—Cut the Head and Tail—Middle Rolling Unit—Broken Tail—Prefinishing Rolling Unit—Finishing Rolling Unit—Pinch Roll—Spinning—Loose Cold Cooling-Rolling-Collecting-Packing-Listing-Lifting and Weighing-Storage

Equipment composition:

Φ320 roughing rolling mill 1set

Φ250 one drive two rolling mill 7set

Accessory Equipment:

1. coil upender 1set
2. scatter-cold chain 1set
3. Head cutting shear 1set
4. Tail cutting shear 3sets
5. Roller bed before breakdown 1set
6. Lifting platform 1set
7. Hanging arm roll 1set
8. Roller bed before continuous rolling 1set
9. Collection machine 1set
10. Laying head (include pinch roll set) 1set

Melting equipment:

2 tons medium frequency induction furnace 3sets
R4000-70 single-strand casting machine 1set

Heating furnace:

Furnace body 1set
Pushing device 1set
Discharge machine 1set
Chimney 1set
Burner 1set
Fan 1set
Heat exchanger 1set

If you are interested in the wire rod production line, please mail at marketing2@hanrm.com.

Monday, May 11, 2020

Common Accidents on the Site of High-speed Steel Rolling and Measures (4)

15. What are the reasons for stacking steel between the stands of the finishing mill?

(1) The rolling guide sticks the steel;

(2) The guide wheel does not turn or the bearing burns out;

(3) The rolled piece split;

(4) The guide or the roll ring is installed incorrectly;

(5) The roll gap is not set properly or the incoming material size is not reasonable;

(6) The guide is not fastened.

16. What are the reasons for the poor wire loop of the laying head outlet?

(1) The tension between the rolling mills is too large;

(2) the alignment deviation of the water cooling section, the nozzle duct wear and corrosion cause the rolling operation to be unstable;

(3) The clamping force of the pinch roller is not appropriate due to the wear of the pinch roller ring or the failure of the cylinder link mechanism;

(4) The deviation of the bending line of the spinning tube, the spinning tube is seriously worn, and the spinning tube is sticky connected, the unbalance of the spinning tube causes the loop formation difference;

(5) Improper speed configuration of the finishing mill, pinch roll, and laying head, serious speed fluctuation of the rolling mill, causing the rolling speed to be faster or slower, resulting in uneven coil size;

(6) When the temperature of the rolled piece is high, the coil is too soft, and the coil falls on the receiving platform, and it will become an ellipse or a random circle.

17. What are the common types of damage to rolling guides in finish rolling? What are the causes? How to prevent it?

1) The guide roller bearing is broken, so the guide roller cannot rotate;

2) The guide roller is short of oil, and the bearing is locked;

3) The guide roller lacks water, causing the guide roller to not rotate or burst;

4) The guide roller shaft is broken;

5) The guide roller moves, the screw of the pin is loose;

6) The guide arm is loose.

Solutions:

1) Strictly control the size of the red billet, ensure the same size as the guide, and prevent the thickness of the material from impacting the guide roller.

2) Prevent misalignment of the roll ring, prevent twisting of the rolled piece, and the rolling guide is damaged. The bottom surface of the roll ring needs to be aligned with copper skin.

3) To prevent the roll ring from moving, due to the roll ring movement, the torsion moment is generated in the rolled piece.

4) The guide guard must be aligned to prevent excessive force on one side of the guide roller.

5) Strictly control the installation quality of the rolling guide, prevent the guide roller from moving, the guide guard arm is loose, and the cap screw is tight.

6) Strictly check whether the oil pipes and water pipes are working properly.

18. What common accidents will occur during the production of 27 high-speed roll rings with misaligned holes? How to solve it?

1) The serious slope of finished product;

2) The rolled parts are twisted, are unstable in the water-cooled channel, and are easy to get out of the waste box;

3) Due to the torsion of the rolled parts, the finished guides are easy to damage, resulting in the quality accident;

4) The guide is not easy to align.

Solution: Add copper skin to the bottom of the roller ring.

19. How to deal with the sudden stoppage of the high-speed wire mill?

1) Immediately start flying shearing machine #1, #2, and #3;

2) Emergency stop finishing and pre-finishing;

3) Notify the dispatch room to find the reason;

4) After stopping, ask an operator to the finishing mill to check the condition inside the machine;

5) Roller ring was all replaced or slowly cooled, it is strictly prohibited to cool the roller ring with water.

More Articles You May Be Interested:

1. What are the Main Safety Technologies for Steel Rolling?

2. How to Choose Steel Rolling Mill Machine?

3. Heat Treatment Method for Steel Rolling Mill

4. Rolling Steel Pressure Processing Technology

5. Rolling Steel Production System

6. The practice of Direct Rolling without Heating

7. What Adjustment Devices Are There in the Rolling Mill?

8. What Are the Rolling Process Systems?

9. Key Factors Affecting Rolling Mill Prices

10. Should Customers Choose Used Rolling Mill?

Wednesday, May 6, 2020

Common Accidents on the Site of High-speed Steel Rolling and Measures (3)

12. How to judge the tension between each rolling mill stand in production?
For the tension between the stands of the rolling mill, the adjuster generally hits the tensional rolled piece with a pipe, and judges the magnitude of the tension based on his experience, and can also observe the load (current magnitude) of each mill stand. If the load of one motor in the adjacent frame is particularly small, and the load of the other motor is too large (the current is too large), it means that there is severe steel drawing between the frames, which is easy to pull off the rolled piece and cause piling-up of steel.

13. How to deal with common faults in loopers?

The most common failure is that the looper cannot detect the rolled piece, the looper cannot afford the loop, the looper raises the high loop, and the looper shakes greatly.

(1) The looper cannot detect the rolled part. The usual reason is that the looper scanner lens is dirty or the looper scanner is not aligned with the steel. The solution is to wipe the looper lens first, and then test looper scanner (calibration loop) with the test rod.

The test method is to put the test rod in the looper table. The brightness of the test rod is similar to that of the red steel. Move the test rod slowly from the bottom of the looper table. If the signal does not arrive or is unstable, move the looper scanner to the left and right until it is aligned with the looper scanner head, unless the steel hits the scanner and is fixed after alignment. The possible reason is that there is too much cooling water in the looper table, and the cooling water needs to be reduced appropriately.

(2) The looper can't afford. There may be two situations: the air valve is leaking; the air valve pressure is not enough; The valve is not energized. The first two reasons are dealt with by overhaul, and the latter is checked by electrical to check whether the cable and wiring are firm.

(3) The looper raises its height. If the operator sets the parameters improperly, it can be solved by the operator modifying the parameters.

(4) The looper shakes greatly. It may be that the water mist is too large, which affects the looper signal. A fan can be placed next to the looper to blow.

14. Reasons and countermeasures for looping tail

① Improper setting of the set-up time will cause the set-up time to be too late, which will directly lead to slipping of the loop.

②Severe out-of-tolerance of the red billet size of the front frame of the looper and the excessive opening or excessive wear of the corresponding rolling guide will cause the looper at the tail of the rolled piece to flick intermittently in the retracted state.

③ The electrical control system is abnormal, and the joint adjustment between the roughing and intermediate rolling units is interrupted. The intermediate rolling speed continues to rise with the loop rising, but the speed of all 6 rolling mills in roughing rolling does not increase with the joint adjustment but always remains the same. The situation caused 4# or 6# tails to be flicked, and in severe cases caused the tail to be held back.

④ The action of the roller wind valve of the rising looper is delayed, resulting in the looper falling time being too late, which will directly cause the looper to flick.

⑤ The main method of controlling the looper tail dumping is as follows: reduce the height of the tail of the rolled piece and set the closing time of the take-up loop roller accurately.