What Is Universal Rolling Mill?

The universal rolling mill is composed of a pair of horizontal rolls and a pair of vertical rolls. The axis of the four rolls is in a plane. The horizontal rolls are the driving rolls and the vertical rolls are the driven rolls (some rolling mill vertical rolls can also be driven). It can process the rolled pieces on four sides, and the two-high horizontal rolling mill is used as the auxiliary stand (edge ​​rolling machine).

Universal rolling mills are mainly used to roll various types of steel, such as H-beam, rail, I-beam, channel steel, steel sheet pile, U-beam, L-beam, unequal angle steel and other types of steel, because it is suitable for many Variety of steel rolling, hence the name "universal rolling mill".

Features of Universal Rolling Mill

1. The complex section shape composed of four rollers can compress all components of the section at the same time, the deformation of the rolled piece is uniform, the speed difference around the section is small, and the internal stress of the rolled piece is small.

2. Rolls with a smaller diameter can be used (because there is no need to slot on the rolls) to roll products with higher legs and wider waists, and the inner sides of the legs can be made without slope. This is difficult to achieve on an ordinary two-high rolling mill.

3. The reduction of the leg and waist of the rolling piece can be adjusted separately, which simplifies the adjustment of the rolling mill during rolling.

4. The rolling precision is high, the roll wear is less, and the energy consumption is reduced.

According to the structure of the universal rolling mill, there are four main types: closed-end, UD (Universal-Duo) prestressed/short-stressed, SC (Schloemann-Siemag compact stand) connecting plate three-type and compact rolling mill.

The Development History of Universal Rolling Mill

1. The world's first universal rolling mill was built in the Arbed factory in Luxembourg in 1902, but the I-beam with a wider flange was rolled at that time, and the inner side still had a slope.

2. In 1914, the German Payin Company adopted the Green rolling method (a side rolling mill and a universal rolling mill are used together) to build the Payin H-shaped steel plant; the rolling of the rails adopts the traditional two-roll pass method.

3. In 1973, the French Vendell-Sidelor Company developed a new process for rolling steel rails on a four-high rolling mill and obtained a patent. Japan, Brazil, and the United States have followed suit and introduced them.

4. In 1998, Maanshan Iron & Steel rolled out China's first H-beam with a universal rolling mill imported from abroad.

5. Localized import and export: Since then, Laiwu Steel, Rizhao, Jinxi and other steel mills have successively introduced foreign universal rolling mills. By 2007, the number of universal rolling mills in China has shown a rapid increase, and most of the equipment has been imported at high prices from abroad. Among them, in 2003, the 300H section steel production line designed and manufactured by Tianjin Zhongzhong Science and Technology Engineering Co., Ltd. was put into operation, marking the official launch of China's self-developed universal rolling mill. Since then, the universal rolling mills of Dalian Zhengda, Tangshan Shengda, Anshan Zizhu (Anshan No. 3 Rolling), and Anshan Baode, designed and manufactured by Tianjin Zhongzhong, have been put into operation one after another.

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

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Heating Furnace What You Need to Know

1. Heating furnace's purpose

The heating furnace is to heat the billet to a uniform temperature (austenite structure) suitable for rolling. After the temperature increases, the first thing is to improve the plasticity of the steel and reduce the deformation resistance, so that the steel is easy to deform. For example, the deformation resistance of T12 steel is about 600 MPa at room temperature, and it decreases to about 30 MPa when heated to 1200 ℃, which is only one twentieth of that at room temperature.

For the steel with proper heating temperature, a larger reduction can be used during rolling, which can reduce the equipment accidents caused by wear and impact, improve the productivity and operation rate of the rolling mill, and reduce the rolling energy consumption. Secondly, heating can improve the internal structure and properties of the billet. The inhomogeneous structure and non-metallic inclusions are homogenized by the diffusion of high-temperature heating. The heating temperature and uniformity are the marks of heating quality. The steel with good heating quality is easy to obtain the finished product with the correct section shape and accurate geometric size.

2. Heating furnace's heating process

The heating temperature of the billet includes surface temperature, temperature difference along with section and temperature difference along billet length. The final heating temperature of the billet in the furnace is determined after considering the actual situation of the rolling process, structural characteristics of the rolling mill and heating furnace. The time required for heating to the specified temperature depends on the billet size, steel grade, temperature system adopted and some other conditions.

The billet gets heat by convection and radiation in the heating furnaces. The former is that the furnace gas washes the billet surface, while the latter is that the furnace gas and hot lining radiate heat. Along the length direction, our furnace is divided into three sections: preheating section, heating section and soaking section. When the billet enters the preheating section of the heating furnace, the heat flux increases gradually. When the billet reaches the second heating section, the heat flux basically remains unchanged. When the billet reaches the soaking section, the heat flux decreases gradually.

In the soaking zone, the surface temperature of the billet remains basically unchanged, while the temperature difference of the cross-section decreases gradually, and the heat from the billet surface diffuses to the interior in the way of heat conduction. The smaller the heat flux to the billet surface, the larger the heating area, the smaller the section size of the billet and the greater the thermal conductivity of steel, the smaller the section temperature difference. Generally, the heating time of billets with large section is longer than that of billets with small section, and that of alloy steel is longer than that of carbon steel.

3. Heating furnace pressure system

The size and distribution of the heating furnace pressure are an important means to adjust the temperature field, control the flame and atmosphere in the furnace. It affects the heating speed and quality, and also affects the utilization of fuel. In particular, the furnace pressure at the discharge section of the furnace is particularly important.

The heating furnace pressure should be set at 0 ~ 30Pa higher than atmospheric pressure. If the furnace pressure is too high, the charging port, discharging port, observation hole and other opening parts will be exposed to fire. The results are as follows: (1) the furnace gas loss increases, which increases the heat loss; (2) SO 2 and other harmful gases enter the workshop, which pollutes the working environment; (3) the furnace wall, nearby steel structure or mechanical equipment at the burning part are damaged or deformed. On the contrary, if the furnace pressure is too low, the absorption of cold air in the workshop will make (1) the furnace temperature decrease and the fuel consumption increase; (2) the cooling of billet by low-temperature air will lead to uneven temperature; (3) the increase of oxygen content in the furnace gas will lead to the increase of burning loss.

4. Heating furnace combustion system:

The basic requirement is to ensure that the fuel is completely burned in the heating furnaces and the air coefficient α is small. Excess air leads to a large amount of flue gas and more heat carried away; insufficient air leads to incomplete combustion in the furnace, which also increases heat loss.

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

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How to Choose the Right Roll?

Residual stress and thermal stress will occur in the preparatory process before the roll is manufactured and used. During application, it was further subjected to various periodic stress effects, including tortuosity, change, shear force, contact stress and thermal stress. The distribution of these stresses along the roll body is uneven and constantly changing. The reason is not only the planning factors, but also the continuous changes in the wear, temperature and roll shape of the roll in use. In addition, rolling conditions often exhibit abnormal conditions. Improper cooling of the rollers after application will also be endangered by thermal stress.

Therefore, in addition to wear, the roll often exhibits various partial damages and appearance damages such as cracks, fractures, flaking, and indentation. A good roll should have a better match between its strength, wear-resistance and various other performance indicators. In this way, it is not only durable under normal rolling conditions, but also less damaging when presenting some abnormal rolling conditions. Therefore, when making rolls, the metallurgical quality of the rolls must be strictly controlled or supplemented with external measures to enhance the bearing capacity of the rolls.

Various types of rolling mills produce long products. Therefore, the selection and layout of rolling mill types, the selection of roll materials, and the determination of roll sizes are also very wide. At the same time, the rolls selected by different rolling mills are also different, and the rolls need to be selected according to production requirements.

Before choosing the right roll to increase productivity and improve product quality, you need to fully understand the types and configurations of various mills.

1. Bar and small section rolling mill

Generally speaking, bar and small section rolling mills can use either steel ingots with a size range of 80 to 150 mm or continuous casting billets with the same size range to produce small profile and bars. The initial feed temperature of the bar and small profile rolling mill is 1200°C. The rolling mill can be produced either semi-continuously or fully continuously. Continuous rolling mill is the current development trend, during which there are rough rolling, intermediate rolling and finishing rolling stands. The roughing stands are arranged in horizontal/vertical order, which mainly depends on the product composition. The intermediate stand and the finishing stand can be either vertical or horizontal. For the bar, the rolling mill constitutes more vertical stands, while for other small profiles, the horizontal stand is often used.

In the small profile rolling mill, the diameter of the selected roll is 300-600mm, and the length of the roll body is 700mm according to the difference between the raw materials fed and the final product size. For product tolerances, users generally require one-third of international tolerance standards, and products must have a good surface finish. For small profile, the rolling speed of the rolling mill is from 12m/s to 20m/s, while for the bar rolling mill, the rolling speed has been increased to 36m/s.

2. Wire rod rolling mill

Wire rod rolling mills have rough rolling stands and intermediate stands similar to small profile rolling stands. Compared with small profile rolling mills for two-line rolling, these mills are generally designed to perform split rolling for simultaneous rolling of up to four lines. However, the current development trend is to use single-line high-speed rolling. Modern wire rod rolling mills generally have 8 to 10 non-twisting stands, which are arranged at an angle of 90° to each other in the finishing mill.

At present, the diameter of the rolls used in wire rod mills is limited to 200mm. The rolling speed can be as high as 140m/s.

3. Medium profile rolling mill and large profile rolling mill

After the rough rolling stand, the medium profile rolling mill has two sets of continuous stands. Continuous rolling mills can be arranged horizontally or vertically according to the pass design. For the section steel and channel steel with parallel edges, there is also a universal frame. When rolling other profiles, the universal frame can be replaced with the horizontal frame. The rolls of the horizontal frame have a deep hole pattern, but the universal frame does not.

The larger-diameter horizontal roll determines the shape of the section steel, and the smaller-diameter pair of vertical rolls are used to roll the edge. When the billet passes through the finishing rolls of the traditional stand and the universal stand, a good surface finish and dimensional tolerance can be obtained.

Roller parameter selection

-Rolled steel grade

The rolled steel type is the key factor for selecting the roll. Its deformation resistance varies with the chemical composition of the billet, which is mainly reflected in the size and change of the deformation load at each stage of rolling. The roller must be selected according to the determined strength and hardness.

-Rolling mill layout and pass design

The position of the stand on the production line and the design of the pass has a great influence on the choice of rolls. Depending on the position of the stand, the force mode and performance of the rolls can vary greatly. This is because the rolls applied to the rough rolling stand and the finish rolling stand have very different stress modes, resulting in expected changes in roll performance. In addition, the time interval between the passage of a billet and the next billet and the productivity of the rolling mill also has a great influence on the choice of rolls. It can be observed through experiments that roll bending and torsional stress combined with high rolling pressure are the factors that determine the selection of rolls for rough steel stands. However, in the finishing stand, hardness, wear-resistance and surface quality are the key factors for roll selection.

-Friction between roller and billet

Due to the difference between the circumferential speed of the roll and the billet speed, friction plays a very important role, especially at low speeds, such as blooming mills and roughing stands. Therefore, the relevant data creates conditions for the proper selection of rolls to suit a particular stand.

-Hot state

The thermal conditions of the rolls and rolled billets are also very important. The main reason is that the temperature of the roll is much lower than that of the rolled billet. Therefore, the roll is susceptible to high thermal shock in a short period of time, resulting in the formation of burnt cracks on the roll surface and further spread to form fatigue cracks. Therefore, the selection of rolls should take into account that roll cracks are minimally generated and propagated under rolling conditions.

-Roller cooling

The effectiveness of the roll is also related to the layout of the rolling mill coolant. The thermal conductivity of the roll material has a great influence on the cooling of the roll. The higher the thermal conductivity of the roll material, the higher the requirement for effective cooling, mainly to avoid the occurrence of cracking, resulting in a reduction in roll life.

Choose the roll according to the type of rolling mill

The selection of rolls is very skillful. The experience of the rolling mill operator plays a decisive role in the selection of rolls.

-Bar and small rolling mill

The requirements of this type of rolling mill for rolls are ① relatively good bending strength against impact; ② uniform hardness of the roll; ③ higher wear resistance; ④ better resistance to cracking.

If you are looking for rolls of rolling mills, please contact me.
Email: marketing2@hanrm.com; Whatsapp / Wechat: +8618392033938

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Common Accidents on the Site of High-speed Steel Rolling and Measures (1)

1. Jamming of steel

Reasons: ① The roll gap on both sides of the roll is inconsistent.

② The gap of the input box is severely worn, the gap is too large.

③ The axially fixed pressing block of the roll is not fastened, which causes roll error in rolling.

④ Incoming materials are out of square or severely reversed.

⑤ Long-term wear of the hole type is on the left or right side.

Measures: ① Adjust roll gap;

② Replace the input box;

③ Tighten the axial fixed pressure block to eliminate the roller error;

④ Remove the raw materials with serious detachment;

⑤ Change the slot.

2. Rolled piece do not bite

Reasons: ① The reduction is too large;

② The grinding groove is not good or there are water and oil on the surface of the groove;

③ The sliding plate on the inner side of the card-breaking shear is not welded or moved laterally;

④ The head of the incoming material is off square or has a large deformation during cutting, and it is stuck in the input box.

Measures: ① Reduce the reduction of this pass, enlarge the roll gap appropriately, and then press back to the normal range after normal rolling, the billet head is cut into a wedge or cone shape, when changing the roll or groove (When the rolling stop time is sufficient), press the head of the billet a little bit in advance, stop the machine and then go out of the rolling mill and return to the heating furnace to reheat.

② Grind the grooves in place to increase the surface roughness of the grooves and remove oil stains;

③ Check the shearing machine and rolling mill processing;

④ Remove the raw materials with severe head deformation or cutting.

3. Rough and medium-rolled slipping steel

Reasons: ① The reduction is too large;

② The grinding groove is not in place;

③ Turn on the cooling water in advance;

④ There is oil on the surface of the groove;

⑤ The gap between input guides is small;

⑥ The speed of the front frame has not been reduced (2.5% ～ 3%) just after the rolling.

Measures: ① Properly enlarge the roll gap and press it back to the normal range after normal rolling;

② Grinding groove in place;

③ Avoid turning on the cooling water in advance;

④ Remove the oil stain on the surface of the rolling groove;

⑤ Check the gap between the input guides;

⑥ Slow down after changing the roller and groove.

4. Head rolling steel during rolling

Reasons: ① The size of the rolled product in the previous pass is too large, so that when the rolled product enters the next pass, it is squeezed in the entrance guide plate to cause suffocation;

② Due to the uneven deformation of the billet head during rolling, the temperature of the billet head is low may cause the steel to split;

③ The rolling guide is seriously worn, the guide roller does not rotate, and the guide roller arm is loose, which causes the guide roller gap to change, causing steel holdback;

④The elbow of the rolled piece does not lead to the next lane, causing steel holdback.

Measures: ① Adjust the material type;

② Avoid low-temperature steel, pay attention to the condition of the billet head and avoid splitting the head;

③ Regular shut down to check the input and output guide to avoid holding back the steel;

④ Avoid elbows;

What we can do:

We are specialized in manufacturing high-speed morgan wire rod mill, high-speed rebar rolling mill, TMT rolling mill, high-speed gearbox, hard-faced gearbox.
We also provide complete design for your rolling mill workshop, not only turnkey project but also tailor-made service.

And we provide all the parts for roughing rolling mill, intermediate rolling mill process, including pinch roll, all kinds of shears, laying head, all of these crucial parts work extremely precisely and reliably.


If necessary, please feel free to contact me. Email: marketing2@hanrm.com

Reasons and Solutions for the Piling of Wire Rod Rolling

1. Piling of Steel Head

The Reason:

1) The friction of the rolling groove after changing the roll and groove is too small, causing the head of the rolled product to slip;

2) The head of the rolled product is tilted out of the rack, causing it to fail to bite into the downstream rack or the head guide position smoothly;

3) There are foreign objects in the rolling groove or guide groove;

4) The billet is severely out-of-square, unable to enter the rolling mill or take out the outlet pipe;

5) The blank is split out of the guide or wrapped around the roller.

Solution:

1) Increase the groove friction when changing rolls and grooves. Grind the grooves with the grinder or use spot welding, and turn off the cooling water of the rolls until they are completely bitten.

2) Check whether the guide base is loose and whether the rolling line is centered, and replace the old guide in time.

3) In the rolling process, timely clean up the oxide scale;

4) In the rolling process, unqualified billets are removed in time, and splitting occurs. Emergency stops should be taken as soon as possible to reduce the waste steel processing time.


2. Piling of the Middle and End of the Rolled Piece

The Reason:

1) Due to improper roll gap setting caused by improper size of rolled products, stacking steel;

2) Defects of the billet, such as inclusions, bubbles, etc., are broken during the rolling process and cause stacking of steel;

3) The speed of the rolling mill is improperly designed, and it is in the state of stacking and rolling. When the first half of the rolled product is maintained by the front rolling mill to maintain micro-tension rolling, when the tail of the rolled product leaves the front rolling mill, the tension is suddenly lost there, causing the stack at the stand tail;

4) Sudden increase or decrease in speed of the rack motor caused the stacking of steel;

5) The roll was suddenly broken or the guides were severely damaged in the first few passes, which caused the stacking of steel.


Solution:

1) After changing rollers and grooves, accurately set the groove bottom, correctly measure the diameter and speed of the rollers, and reduce speed errors

2) Strengthen the inspection of unqualified blanks;

3) Correctly adjust the tension between each frame;

4) Inspect electrical equipment and replace damaged electrical components;

5) Check the amount of roll cooling water, adjust the steel temperature, and prohibit rolling of low temperature steel and blackhead steel.


3. Piling steel between Finishing Mill Stands

The Main Reason:

1) The guide wheel does not rotate or the bearing burns;

2) splits of rolled products;

3) The guide or roller ring is incorrectly installed;

4) Improper roll gap setting or improper incoming size;

5) the roller ring is broken;

6) The broken line causes the rolling line to break automatically.


Solution:

1) Replace the guide, and strengthen the correctness of the guide installation;

2) Strengthen the blank inspection and lengthen the cutting head;

3) Recheck and adjust the roll gap;

4) Replace the roller ring and check the cooling water pipe at the same time;

5) Check the switch at the fishing line pendant, check whether there is scrap steel in the guide of the finishing mill. If there is any, it means that the previous one has piled steel in the finishing mill, and reset the roll gap in the finishing mill.

What we can do:

We are specialized in manufacturing high-speed morgan wire rod mill, high-speed rebar rolling mill, TMT rolling mill, high-speed gearbox, hard-faced gearbox.

We also provide complete design for your rolling mill workshop, not only turnkey project but also tailor-made service.

And we provide all the parts for roughing rolling mill, intermediate rolling mill process, including pinch roll, all kinds of shears, laying head, all of these crucial parts work extremely precisely and reliably.

If necessary, please feel free to contact me. Email: marketing2@hanrm.com

Classification and Development of Direct Rolling and Hot Feeding

The real direct rolling is to roll the continuous casting slab sent from the continuous casting machine directly into the final product without any other heating or heating process. However, for many years, most of the production process research and tests for producing high-quality products have reheated or reheated the continuous casting slab before rolling.

Continuous casting slab hot feeding and hot charging and direct rolling technology are new technologies under development, and the specific characteristics are as follows:

Continuous casting slabs are directly rolled without heating or supplemental heating, referred to as CC-FDR, and are classified into 1 type. Under the condition that the surface temperature is above 820 ° C (the core is above 960 ° C), the continuous casting slab is directly sent to the rolling mill without any form of heating and supplemental heating, and without building a heating furnace. The slab has not undergone the γ-α-γ phase transformation recrystallization process before rolling, and the as-cast coarse austenite grains are still retained. The trace elements Nb and V do not have the precipitation and re-dissolution processes in conventional cold-loading furnaces, so they must be developed. A new rolling process to obtain a grain-refined structure.

Continuous cast slab rolling, referred to as CC-DR, is classified into 2 types. The continuous casting slab is directly sent to the rolling mill through the corner heating device during the conveying process without passing through the heating furnace under the conditions above A3 temperature.

Continuous casting slab hot direct rolling, referred to as CC-HDR, is classified into 3 categories. The continuous slab temperature is above A3. The slab does not pass through the heating furnace. During the conveying process, the rollable temperature is reached by supplementary heating and soaking, and it is directly sent to the rolling mill for rolling.

Continuous hot-rolling of continuous casting slabs, referred to as CC-DHCR, is classified into 4 categories. The continuous casting slab temperature is below A3 and above A1, and the casting slab is directly sent to a heating furnace for heating and rolling. Due to the high temperature of hot charging, it is also called red delivery, and the heating furnace acts as a buffer between the continuous caster and the rolling mill.

Continuous hot-rolling of continuous casting slabs, referred to as CC-DHCR, is classified into 4 categories. The continuous casting slab temperature is below A3 and above A1, and the casting slab is directly sent to a heating furnace for heating and rolling. Due to the high temperature of hot charging, it is also called red delivery, and the heating furnace acts as a buffer between the continuous caster and the rolling mill.

The continuous casting slab cold rolling furnace is heated and rolled, referred to as CC-CCR, and is classified into 6 categories. This is the conventional rolling method when there is no hot-feed and hot-fill process.

Repair Method and Operation Process of Rolling Mill Roll

During the operation of the rolling mill, the roll is easy to be damaged. In order to repair the roll body timely and effectively, it is necessary to judge and analyze from the determination of service life, the identification of crack depth, turning crack and other aspects, so that the rolling mill can return to normal.

Because there is no good method to detect the crack depth of the rolling mill roll, the length of service life can only be judged and determined according to the experience, the type of rolling mill, the type of alloy produced and the roughness of the roll surface. According to the theory, the correct service life should be before the crack depth reaches 3 mm, beyond which the roller surface should be grinded, otherwise it is easy to cause the roller sleeve to burst.

In general, if the crack on the rolling mill roll is open, its depth is deeper than tortoise crack or other microcracks, and the crack width is also larger. Therefore, the longest circumferential crack and the widest crack on the roll surface must be found out correspondingly. Through these cracks, the minimum cutting amount can be determined, and the magnetic particle inspection can be used for crack areas.

In order to ensure the safety, the turning depth of the rolling mill roll needs to add 0.5mm to the crack depth in general, and the roughness of the roll surface after turning shall not be less than 6.3; the surface roughness of the roll surface after grinding shall reach 0.8, which can be compared with the standard block or measured with the roughness detector.


When the defects of the rolling mill roll are turned, magnetic particle inspection shall still be carried out to ensure that all micro-cracks have been eliminated. If there are still micro-cracks, turning is still required. It should be noted that every time the repair is made, the record should be made and kept for the daily backup.

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How to Adjust the Roll Gap?

Adjusting roll hole shape and controlling plate shape are mainly based on rolled products. The rolls are supported and held in a fixed position in the rolling mill. Roller bearings have a large workload and vary widely, so a small coefficient of friction is required.

After determining the products rolled by the rolling mill, the line speed of the rolling mill can be basically confirmed. The hardness of the raw material is measurable. The rolling stock of the rolling mill is determined by changing the plastic deformation size.

How to configure the rolls according to the hole process? Generally, the newly installed rolling mill has a running-in process. During the running-in process, the rolls are run at no load, and the running speed is 50%, 65%, 75%, and 85% in stages. Different rolling mills have different materials and specifications for rolls according to different rolling products.

For example, the continuous casting machine and rolling mill has a daily output of 100 tons and a rolling speed of 15-25 m / s. Rough rolling efficiency accounts for 30% -40%, intermediate rolling efficiency accounts for 50% -60%, and rough rolling efficiency reaches 95%. After the rolling mill is installed, the large and small teeth of the reducer and gearbox need to mesh, the rolling speed is too fast, and the torque is enhanced. After the rolling mill runs normally for 30 consecutive days, stop the rolling mill to check the meshing of the large and small gears. When everything is normal, the rolling speed can be increased.

Under normal circumstances, there is no need to adjust the rolling speed. In the rolling mill, the rolls are constantly worn during operation. In order to maintain the stable operation of the rolling mill when the rolls are under controllable rolling requirements, the rolls must be repaired in time. In severe cases, the rolls need to be replaced.

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Solution to High Temperature of Rolling Mill

In summer, we should pay special attention to the safe operation of the rolling mill in the high-temperature natural environment, improve its maintenance and repair, because the temperature rise is more likely to cause small problems of the rolling mill. First of all, the cooling circulating water of rolling mill roll can not be less, the average temperature is high, and the cooling circulating water volatilizes too fast, which should be added frequently. And check the body of water in time, and if the water body smells smelly, it is necessary to dismantle and replace the cooling circulating water, throw away the sewage, replace the saponification liquid again, and add the water that must be accounted for.

If the rolling mill works for a long time, it will also cause the temperature of the motor to rise, so you have to touch the bearing end cover shell of the motor by hand to see if the temperature is too high. If the temperature is high, it needs to be shut down to reduce the temperature of the motor before it works without overload.

The cycloid reducer is used in the rolling mill, and the installation method is inverted. In high temperature, the temperature rise will occur, which makes the viscosity of the lubricating grease lower and lower, and it will flow into the bearing end cover, resulting in the lack of lubricating grease in the cycloid reducer, leading to the temperature rise of the reducer, and the more severe one will burn the reducer. Therefore, it is necessary to often check whether there is a lack of grease in the reducer to ensure the normal operation of the reducer.

In summer, it is also necessary to check the route of household electrical appliances of rolling mills. The rise of average temperature will accelerate the embrittlement of the route, which is easy to cause short-circuit fault. However, the actual operating staff of the rolling mill shall wear rubber gloves during safe operation, and the temperature of spiral gear after cold rolling is too high, which will burn their hands.

In addition, the roll of the rolling mill shall be cleaned. At the end of daily work and after standby, the roll must be removed. Clean the roller surface with a clean towel and wipe off the air oxide skin adhered on the surface, so as to improve the service life of the roller.

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Rolling Mill Packaging, Transportation and Storage Requirements

We have introduced a lot of knowledge about the use and operation of rolling mills. However, if we want to ensure the normal use of the rolling mill machine, we need to comply with certain requirements for its packaging, transportation, and storage. Now we will introduce this aspect for you, hoping to provide a reference. 

First of all, let's take a look at how to properly pack the rolling mill. In general, since the equipment is shipped in bulk during transportation, it is required to wrap the motor part with a plastic cloth during packaging so as to prevent damage due to moisture. In addition, the shaft head of all exposed parts also needs to be wrapped with plastic cloth to prevent damage and corrosion.

As for other parts of the rolling mill, it is necessary to apply antirust oil in advance to avoid rusting in early summer. Therefore, in the process of transportation, what should we pay attention to? When loading, unloading and hoisting the equipment, it is necessary to operate it carefully and ensure that the rope used has sufficient strength. At the same time, it should be noted that the protruding part of the equipment shall not be damaged during lifting, and it is better to use some soft things for protection.

In the process of transportation, it is necessary to ensure that the rolling mill machine is fixed so as to avoid sloshing, and no strong vibration or impact. During the driving process, the speed should be uniform and the driving should be stable. In addition, we also need to pay attention to some problems when storing the product.

When the rolling mill arrives, we need to remove it from the box and check it carefully. The rolling mill equipment is then placed in a ventilated and dry room to prevent rust damage. If long-term storage is required, it should be cleaned and rust-proofed.

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Eight Precautions for Rolling Mills

1. Every time the rolling mill appears to be jogging, it must not exceed one second. The worm gear should be adjusted in place, and the adjustment amount should be completely equal on both sides to avoid side bends.

2. When operating the cold rolling mill, there should be a special person to guard, and there should be no phenomenon of no one to guard, so as not to find the equipment failure and not find it in time.

3. Under normal circumstances, a single cold rolling mill should not exceed 40% of the aluminum plate in a single thickness.

4. There must be no debris in the production line.

5. Adjust the amount of reduction and the number of passes according to the material of the incoming material and the capacity of the rolling mill.

6. When using a cold rolling mill, the relevant technical parameters must be in full compliance with the requirements, and it should not be operated under load.

7. Rolls should not be subjected to more serious wear and should be replaced if they are found to be worn out.

8. During the whole rolling process, if the roll affects the surface quality of the rolled piece due to wear, or the size and precision, the roll should be replaced immediately, and after the roll is replaced, the driving operation must be guaranteed 2 to 3 minutes.

Precautions of Cold Rolling Mill

1. Preparation for Startup

Let the rolling mill equipment idle for about 10 minutes. During this period, observe whether the device is running normally, and add lubricating oil and rolling oil to lubricate the equipment properly according to the regulations.

2. Precautions before Unloading

(1) The press should be raised to the specified position, the reel should be retracted into position, and the hydraulic truck should be prepared in advance for auxiliary discharge.

(2) The aluminum plate plug should be inserted into the jaws successfully, otherwise, it will be difficult to insert.

3. Some Considerations

(1) The time for each jog of the machine should not exceed one second. The turbine should be adjusted to reduce the turbine. The adjustment amount on both sides should be equal to avoid the side bend of the rolled piece.

(2) When the cold rolling mill is running, someone should be responsible for guarding to prevent problems.

(3) Generally speaking, the thickness of one rolling of a single cold rolling mill should not exceed 40% of the aluminum plate.

(4) There should be no debris in the production line.

(5) Appropriate adjustments should be made to the pass and reduction depending on the material of the incoming material and the capacity of the rolling mill.

(6) The use of cold rolling mills should meet the requirements of the main technical parameters and should not be overloaded.

(7) The mill roll should not have serious wear and should be replaced if necessary.

(8) In the rolling process, if the wear of the mill roll has affected the surface quality and dimensional accuracy of the rolled piece, the roll should be changed immediately. After changing the roller, it should idle for 2 to 3 minutes.

(9) If there is any phenomenon such as tearing or skewing of the rolled piece, the hand can not be used. It should be stopped first and then taken out.

(10) Rolled finished products or semi-finished products should be filled out with relevant records and stacked in batches.

How to Carry out Daily Maintenance of Rolling Mill?

Rolling mills are widely used in the steel industry. In order to ensure the smooth running of daily work, daily maintenance is particularly important. It should be noted that the daily maintenance of the rolling mills will affect the service life. So how to carry out the daily maintenance of the rolling mill, how to operate?

Every day, the rolling mill is inspected for oil, water and gas leakage and overheating of the machine parts; reducing the loss caused by the illegal operation of the equipment or maintenance, and when lifting the rubber rolls, take necessary maintenance measures at the chain, rope and end of the roll surface.

The automatic thickness control system on the rolling mill is operated strictly in accordance with the rolling mill operating process and operating methods. The gearbox should be cleaned at least once a quarter. When the roll is fed to the extreme position, special attention must be paid to the safe operation of the rolling mill. Care should be taken when performing the rolling mill operation to prevent the hand from being pressed by the steel plate and being fed together with the steel. When using the aircraft hoisting mill for inspection, be careful not to collide with the machine.

In the rolling operation, the personnel of each department should coordinate with each other and listen to the command of the person in charge of the rolling mill production line. In the rolling process, the roller and the raceway are in line contact or repaired line contact, and the radial bearing capacity is large and is suitable for bearing heavy load and impact load. If irregular noise is found, such as the abnormal phenomenon that the roller cannot be touched by the sudden release of the load after the steel bar is interrupted, it should be stopped immediately and checked, and the steel rolling production line can be completely stopped before being repaired. After the main drive of the motor is stopped, the upper and lower rolls can be lifted and lowered. When cleaning, firstly, in the hot state, stop the oil drain screw on the side of the gearbox, and turn the rollover of the roll and the lifting of the upper roll.

After the end of rolling, the finished material should be cleared, and the equipment maintenance and repair work should be done. In order to strengthen the effective management of the equipment, the equipment utilization rate should be improved, and the power supply should be turned off in time.

The Adjustment of Steel Rolling Mill

Before the steel rolling mill is used, the roll pass, controlling plate shape and backup roll should be adjusted according to the requirement; and the fixed position of the rolls in the rolling mill should be maintained. The workload of the roll bearing is heavy and varies greatly, so the friction coefficient of the bearing is required to be small.

After determining the product rolled by the rolling mill, the line speed of the rolling mill can be basically determined. The hardness of the raw materials is measurable. The rolling stock of the rolling mill is determined by changing the plastic deformation size.
Usually, the newly installed steel rolling mill has a running-in process. During the running-in process, the rolls are operated in a second operation, and the operation speed is 50%, 65%, 75%, and 85%. Different steel rolling mill models use the rolls with different materials and specifications for different rolling products.

After the steel rolling mill is installed, the gears of the reducer and the gearbox need to have meshed, the rolling speed is too fast, and the torque is enhanced. After the normal operation of the rolling mill for 30 days, stop the rolling mill and check the meshing of the large and small gears, and waits for everything to be normal, the rolling speed can be increased.

Under normal circumstances, it is not necessary to adjust the rolling speed. The rolls in the steel rolling mill is constantly worn during the running process. In order to keep the rolling mill stable in the controlled rolling requirements, the roll must be repaired in time, and the rolls need to be replaced in serious cases.

The steel rolling mill needs labor, even the automated equipment needs to be monitored manually in the console. The conveyor roller and shearing machine located in the automatic rolling mill must be strictly controlled during operation to avoid the failure of stacking steel or jamming. If the wear of roll and guide exceeds the specified range, it needs to be replaced. 

The rolling of the billet causes the roll to be squeezed instantaneously, and the bearing is subjected to correspondingly high pressure, thereby affecting the product size of the rolled steel. We may also need to make in-depth improvements, but the ultimate goal is to get better steel rolling mill equipment.

We can supply rebar rolling mill and wire rod mill equipment designing, manufacturing, installation, and commission of the equipment with “turn-key” service.

We can also design, manufacture and revamp other non-standard equipment according to the requirements of users.

If interested, please mail at marketing2@hanrm.com or kerrirollingmill@gmail.com.