TECHNICAL FIELD

The invention relates to the production method of cold rolled hot steel rolls (CHRC) that are needed in various industrial fields such as machinery and construction.

In particular, the invention relates to the performance of production method of cold rolled hot steel rolls (CHRC) that are needed in various industrial fields such as machinery and construction, with the following steps: in order to obtain a cold rolled hot steel roll (CHRC) with a thickness of 0.50 - 1 .60 mm from a hot steel roll with a width of 30-2000 mm and a thickness of 1 .30 - 4 mm;

- directing the hot steel roll loaded to the unrolling car with a width of 30-2000 mm and a thickness of 1 .30 - 4 mm from the unrolling unit to the scraper brush and the air jet,

- during the advancement of the hot steel roll coming to the scraper brush and the air jet, removing the powder scale layer thereon by directing it to the magnetic hood via the scraper brushes and air jet,

- completely cleaning the powder scale on surface of the hot steel roll passing through scraper brush and air jets with scraper felt and water jets,

- directing the hot sheet metal with no powder scale thereon to the tension roll through the inlet straightening unit in order to perform an efficient rolling by reducing the internal tension formed as a result of the hot rolling of the sheet metal as much as possible,

- rolling/extending the sheet metal going through the inlet tension roll by 10% to 60% by entering the driving/non-driving rolling unit, - reducing the internal tension of the sheet metal rolled in the driving/non-driving rolling unit in order to obtain a high quality roll wrapping by passing through the outlet tension roll,

- rolling the rolled sheet metal passing through the outlet tension roll in the rolling unit by straightening it on the outlet straightening unit and packaging it on the roller car,

- bringing the material back to its natural mechanic form by removing the rigidity acquired and extension loss as a result of rolling by passing the rolled sheet metal to the annealing unit,

- if deemed necessary, in order to remove the wrinkles, corrugations and tensions formed on the surface of the sheet metal which has gone through the steps of rolling and annealing units, sending it back to the driving/non-driving rolling unit and performing the temper rolling between 0.5% - %2 and completing the production process of cold rolled hot steel roll (CHRC) with a thickness of 0.50 - 1 .60 mm.

BACKGROUND OF THE INVENTION

Rolled sheet metal is needed in various industrial fields such as machinery and construction.

There are 3 types of rolled steel rolls in the current standards. The first one is the product called hot steel roll (HR) and produced as a result of rolling the raw material (Slab, Billet, Bloom etc.) by annealing at the recrystallization temperature (between 50% - 75% of the melting temperature) of 1000 on average.

The second and third rolled products are cold rolled and they are called CR and DKP.

In both of the production processes, prior to rolling, the hot sheet metal is prepared for rolling by removing more than 90% or even all of the scale layer which has connected with the surface of the stable (powder-scale) and stable material on the surface of the material by means of sand blasting and picking processes (HRP) and it is produced full-hard by cold rolling to 90% (CRF). The problems faced in the production of hot rolls in the state of the art as mentioned above will be explained below. These are;

- Complete removal of the scale later comprises chemicals that are both expensive and harmful to the environment and elimination of the said chemicals constitutes another cost.

- As a result of the complete removal of the scale layer which has established a stable connection with the material, raw steel is made less resistant against corrosion. As a consequence, the formation of corrosion is tried to be prevented by coating with many chemicals (protective oil, corrosion inhibitor) when the material is at the production stage. This then creates operation redundancy, work force, time and associated cost increases.

- A significant part of the businesses that are end-product manufacturers have to clean these chemicals used in order to prevent corrosion of cold rolled sheet metal before the production or during the production or after the production. Otherwise coating of dye cannot establish a connection with the material.

- It makes it necessary to use expensive dyeing techniques even in simple manufactures as the sheet metal surface is extremely clean and smooth.

- As a result of the researches, studies and trials we carried out, we observed that cost advantage of more than 50% is provided with the subject matter production method of cold rolled hot steel roll (CHRC), compared to the cold rolled CR and DKP products.

Accordingly, since in the hot roll production process performed in the state of the art, in order to produce thin sheet metal the necessity of gradual decrease to the desired sheet metal thickness starting from 8 mm of wall thickness and due to the additional costs occurring when the desired thickness is achieved, hot sheet metal production process also comprises a great cost problem compared to the method of the invention. That is, hot rolling rates are roughly the same. That is, while sheet metal with a thickness of 1 .50 mm is produced at a rate of 10 m per second, sheet metal with a thickness of 3 mm is produced with 10 m per second. According to thickness of 3 mm, production tonnage loss is 50% in 1 .50 mm and goes up to 70% in 1 mm. Therefore this increases the cost of hot rolling by up to three times in thin sheet metals. The method of the invention eliminates the cost problems compared to the three types of hot sheet metal production methods performed in the state of the art.

- In the hot rolled steel rolls field, there are about 3-4 businesses worldwide that can produce steel rolls with a thickness less than 1 .50 mm, such as 1 .20 mm and 1 .00 mm. Therefore, it is nearly impossible to find hot steel rolls with a thickness less than 1 mm such as 0.50 mm, 0.60 mm, 0.70 mm, 0.80 mm, 0.90 mm. Sheet metals with a thickness less than 1 .50 mm, including the 1.50 ones, put onto the market with a unit price that is 5% or 25% different compared to the 2.00 mm sheet metals. The reason for this price difference is that, in rolling of hot steel rolls, thick sheet metals need to produced while producing thin sheet metals and there is approximately 70% of tonnage loss in the production of thin sheet metals.

Consequently, it becomes evident that there must be improvements in the art due to the above-mentioned problems faced in the state of the art.

OBJECT OF THE INVENTION

The invention, as a result of the problems present in the prior art, aims to solve all of these problems.

The aim of the invention is to meet the need for thin (0.50 - 1 .50 mm) hot steel rolls in industrial fields such as machinery, construction and manufacture with the production method of cold rolled hot steel rolls (CHRC).

The object of the invention relates to the performance of production method of cold rolled hot steel rolls (CHRC) that are needed in various industrial fields such as machinery and construction, with the following steps: in order to obtain a cold rolled hot steel roll (CHRC) with a thickness of 0.50 - 1 .60 mm from a hot steel roll with a width of 30-2000 mm and a thickness of 1 .30 - 4 mm; - directing the hot steel roll loaded to the unrolling car with a width of 30-2000 mm and a thickness of 1 .30 - 4 mm from the unrolling unit to the scraper brush and the air jet,

- during the advancement of the hot steel roll coming to the scraper brush and the air jet, removing the powder scale layer thereon by directing it to the magnetic hood via the scraper brushes and air jet,

- completely cleaning the powder scale on surface of the hot steel roll passing through scraper brush and air jets with scraper felt and water jets,

- directing the hot sheet metal with no powder scale thereon to the tension roll through the inlet straightening unit in order to perform an efficient rolling by reducing the internal tension formed as a result of the hot rolling of the sheet metal as much as possible,

- rolling (extending) the sheet metal going through the inlet tension roll by 10% to 60% by entering the driving/non-driving rolling unit,

- reducing the internal tension of the sheet metal rolled in the driving/non-driving rolling unit in order to obtain a high quality roll wrapping by passing through the outlet tension roll,

- rolling the rolled sheet metal passing through the outlet tension roll in the rolling unit by straightening it on the outlet straightening unit and packaging it on the roller car,

- bringing the material back to its natural mechanic form by removing the rigidity acquired and extension lost as a result of rolling by passing the sheet metal rolled in the rolling car to the annealing unit,

- if deemed necessary, in order to remove the wrinkles, corrugations and tensions formed on the surface of the sheet metal which has gone through the steps of rolling and annealing units, sending it back to the driving/non-driving rolling unit and performing the temper rolling between 0.5% - %2 and completing the production process of cold rolled hot steel roll with a thickness of 0.50 - 1 .60 mm. An object of the invention is to form a new system of rolling in the production method of cold rolled hot steel rolls (CHRC) by removing the powder-scale which constitutes only 10% of the scale layer and rolling it with the scale layer which has formed a connection with the material.

Another object of the invention is to obtain a cold rolled hot steel (CHR) in the form of a sheet by cutting out the cold rolled hot steel roll (CHRC) in particular dimensions via an external cutting unit, in case obtained cold rolled hot steel is desired as a metal sheet rather than a roll.

Another object of the method of the invention is to meet the need for thin hot metal sheets in the market in the most affordable way. In this way, all of problems such as the difficulty of finding hot metal sheets with less than a thickness of 1 .50 mm (1.00 mm, 1.20 mm, 1 .30 mm), the extremely high prices, hot steel rolls with a thickness between 1 .00 mm - 1 .20 mm being produced by a few businesses worldwide and no production of metal sheets with a thickness less than 1.00 mm (0.50 mm, 0.60 mm, 0.70 mm, 0.80 mm, 0.90 mm) will be eliminated and production of hot steel rolls with a thickness of 1 .00 mm and less will be provided.

SUMMARY OF THE INVENTION

The invention relates to the production method of cold rolled hot steel rolls (CHRC) that are needed in industrial fields such as machinery and construction. In the production process of cold rolled hot steel roll with the method of the invention, the raw material that is hot steel roll with a width of 30 - 2000 mm and a thickness of 1 .30 - 4 mm will be provided as a cold rolled hot steel roll (CHRC) with a thickness of 0.50 - 1.60 mm.

The innovations of the production method of cold rolled hot steel roll of the invention are described below.

As a result of the difficulty of producing thickness of 1 .5 mm and less in the process of hot rolling, the cost of hot rolling is too high and rolling efficiency is extremely low. In the process of hot rolling, it is necessary to start from the production of thick (between 4 mm - 8 mm) in accordance with the process operation in order to produce thin metal sheets (1 .5 mm thickness or less). Starting from the production of thick metal sheets, desired thickness is achieved through gradual decreases in proportion with the thin metal sheet to be produced. When the desired thickness is achieved, gradual decrease from thick to thin must be repeated due to the possible failures during the production.

In the method of the invention, there is no process of decreasing from thick to thin. After desired thickness is achieved, production can be made without depending on any processes. The most important innovation that is aimed and realized can be described in this way.

Despite being compared to the production of hot steel rolls, the method of the invention is included in the process of cold rolling. In many aspects, said method is similar to a hybrid method comprising hot and cold rolling.

The greatest advantage of the method of the invention compared to the cold rolling method is that it does not comprise expensive and environmentally harmful processes such as sand blasting and picking, as mentioned in the present methods and disadvantages of the state of the art.

DESCRIPTION OF THE DRAWINGS

Figure 1 is a process flow chart of the production method of cold rolled hot steel rolls (CHRC) of the invention.

REFERENCE NUMBERS

1. Unrolling unit

1.1. Unrolling car

1.2. Unrolling pressure roll

2. Welding unit

3. Magnetic hood

4. Air filters

5. Scraper brush and air jet

6. Scraper felt and water jet

7. Inlet straightening unit

8. Inlet tension roll

9. Driving/non-driving rolling unit 10. Outlet tension roll

11. Outlet straightening unit

12. Rolling unit

12.1. Rolling car

12.2. Rolling pressure roll

13. Annealing unit

14. Cooling water/oil tanks

DETAILED DESCRIPTION OF THE INVENTION

The invention is a production method of cold rolled hot steel rolls (CHRC) that are needed in various industrial fields such as machinery and construction.

In the the production method of cold rolled hot steel rolls (CHRC) of the invention shown in the chart of figure 1 , the following elements are used:

- unrolling car (1 .1 ) which is used to feed raw material on the line and unrolling unit (1 ) with a moving pressure roll (1 .2),

- welding unit (2) which connects of rolls in order to provide production consistency and prevent time loss,

- magnetic hood (3) which vacuums the particles and, if any, metal pieces coming from the scraper brushes and air jets (5) with air and retains the metal pieces with the magnets therein,

- air filters (4) which retains the particles and foreign substances in the air absorbed by the magnetic hood (3) and releases the fresh air back to the nature,

- scraper brush and air jet (5) which provide the stable operation of the magnetic hood (3) by pushing (directing) the powder scale, particles and foreign substances to the magnetic hood (3) through air and brush that is softer than steel, can not scratch the steel and does not harm the scale that has formed a connection thereon,

- scraper felt and water jet (6) which provide the complete removal of the powder scale on the metal sheet by spraying water with pressure low enough to not harm the scale layer of the steel that has formed a connection but high enough to clean (remove) the moving foreign and unwanted elements through felt and steel that are in contact with the surface of the sheet metal, softer than steel, can not scratch the steel and does not harm the scale that has formed a connection thereon,

- inlet straightening unit (7) which provides the preparation of the metal sheet for a better rolling by removing the internal tensions, edge and surface corrugations and wrinkles, if any,

- inlet tension roll (8) which provides the preparation of the metal sheet coming from the straightening unit for better rolling by further removing the internal tensions, edge and surface corrugations and wrinkles, if any,

- driving/non-driving rolling unit (9) which provide the rolling (extension) of the raw material which has been prepared for rolling by passing through other units, with 10% - 60%.

- outlet tension roll (10) which provides a homogeneous rolling by removing the internal tensions, edge and surface corrugations and wrinkles, if any, of the sheet metal coming from the driving/non-driving rolling unit (9),

- outlet straightening unit (1 1 ) which helps to obtain a more homogeneous rolling by removing the internal tensions, edge and surface corrugations and wrinkles, if any, of the sheet metal coming from the outlet tension roll (10),

- rolling unit (12) with a rolling car (12.1 ) and rolling pressure roll (12.2), which provides a high quality rolling of the sheet metal in the form of a roll in order to obtain a homogeneous and healthy annealing in the annealing unit (13) which recrystallizes the rolled metal sheet,

- annealing unit (13) which removes the rigidity acquired and extension lost as a result of rolling (i.e. all of the mechanic features it has acquired) and brings the material back to its natural form, cooling water/oil tanks which stores the cooling water and/or oil with boron oil that is required during rolling. In the production process of cold rolled hot steel roll (CHRC) which is needed in industrial fields such as machinery and construction, raw material hot steel roll with a width of 30- 2000 mm and a thickness of 1 .30 - 4 mm is produced as a cold rolled hot steel roll (CHRC) with a thickness of 0.50 - 1 .60 mm.

In this process, firstly, the hot steel roll with a width of 30-2000 mm and a thickness of 1 .30 - 4 mm is directed from the unrolling unit (1 ) to the scraper brush and the air jet (5). During the advancement of the hot steel roll coming to the scraper brush and the air jet (5), the powder scale layer thereon is removed by directing it to the magnetic hood via the scraper brushes and air jet (5).

The powder scale on surface of the hot steel roll passing through scraper brush and air jets (5) is completely cleaned with scraper felt and water jets (6). Hot sheet metal with no powder scale thereon is directed to the tension roll (8)through the inlet straightening unit in order to perform an efficient rolling by reducing the internal tension formed as a result of the hot rolling of the sheet metal as much as possible.

Rolling (extension) of the sheet metal going through the inlet tension roll (8) by 10% to 60% is performed by entering the driving/non-driving rolling unit (9). The internal tension of the sheet metal rolled in the driving/non-driving rolling unit (9) in order to obtain a high quality roll wrapping is reduced by passing through the outlet tension roll (10). The rolled sheet metal passing through the outlet tension roll (10) is rolled in the rolling unit (12) by straightening it on the outlet straightening unit (1 1 ) and packed on the roller car (12.1 ).

The material is brought back to its natural mechanic form by removing the rigidity acquired and extension lost as a result of rolling, by passing the sheet metal rolled in the rolling car (12.1 ) to the annealing unit (13).

If deemed necessary, in order to remove the wrinkles, corrugations and tensions formed on the surface of the sheet metal which has gone through the steps of rolling and annealing units, it is sent back to the driving/non-driving rolling unit and performing the temper rolling between 0.5% - %2 and production process of cold rolled hot steel roll (CHRC) with a thickness of 0.50 - 1 .60 mm is completed.

In the operation stages of the method, during the running out of the hot roll (raw material) and feeding a new raw material in the unrolling unit (1 ) which has a unrolling car (1 .1 ) and a moving pressure roll (1.2) used for feeding raw material on the line, in order to provide non-stop and time efficient operation of the line, hot sheet metals are connected to each other by way of welding in the welding unit (2).

In addition, during operation, retainment of the particles and foreign substances in the air absorbed by the magnetic hood (3) and releasing the fresh air back to the nature is carried out via air filters (4). No harm is done to the environment during the application of the method of the invention.

Through the method of the invention, a cold rolled hot steel (CHR) in the form of a sheet is obtained by cutting out the cold rolled hot steel roll (CHRC) in particular dimensions via an external cutting unit, in case obtained cold rolled hot steel is desired as a metal sheet rather than a roll.

As stated in the state of the art, there are three types of rolled steel rolls in today’s standards. The first one is the hot steel roll produced as a result of rolling the material by annealing at the recrystallization temperature (between 50% - 75% of the melting temperature) of 1000 on average.

The second and third rolled products are cold rolled and they are called CR and DKP. In both of these production processes, the hot sheet metal is sent to rolling after preparation by removing more than 90% or even all of the scale layer which has connected with the surface of the stable (powder-scale) and stable material on the surface of the material.

A new system of rolling in the method of the invention described in detail herein, by removing the powder-scale which constitutes only 10% of the scale layer and rolling it with the scale layer which has formed a connection with the material. In this way,

- the need for protective oil/liquid to prevent rusting of the sheet is eliminated,

- end-users (manufacturers) does not need additional operations and chemicals to clean the protective oil/fluid in the productions they carry out using with the cold rolled hot steel roll (CHRC) of the invention, there is no need for expensive dyeing operation for the dye/coating layers to be applied to the surface of the sheet metal, and

- end-users (manufacturers) can supply sheet metals in short time with a low cost.