KR20120073527A - Wire material manufacturing method - Google Patents

Abstract

PURPOSE: A wire rod manufacturing method is provided to increase stability of a rolling process when a driving roll for rolling wire rods changes by changing the speed of the rolling process. CONSTITUTION: A wire rod manufacturing method is as follows. Heated materials are rolled through steps of a roughness mill, an intermediate finishing mill, a finishing mill, and a reducing and sizing mill(RSM). The rolled materials are coiled. The steps of the finishing mill and reducing and sizing mill are rolled by operating some rolls.

Description

Wire material manufacturing method

The present invention relates to a method for producing a wire rod while maintaining the original family method despite the wire rod size change.

Known wire production processes include billets with a cross section of 160x160 mm, heated to a temperature of 900-1200 ° C, which can be rolled in a furnace, to rough rolling, intermediate rough rolling, intermediate finishing rolling, finishing rolling and final rolling (sizing rolling). Carry out a series of rolling processes.

Then, the rolled material is finally produced in a wire rod having a diameter of about 5.5 to 50 mm through a winding process.

That is, the material passed through the heating furnace is hot rolled to a certain diameter through the series of rolling process described above, the rolled material is water-cooled through a water cooling stand to secure the target material, small diameter less than 16mm in diameter depending on the wire diameter The wire rod is integrated after winding in the laying head.

Wire rod rolling process is divided into heating process, rolling process, cooling process, and test / correction process. If surface defects occur in the rolling line, the test process evaluates the quality only by inspecting the sample on the leading end. Therefore, when surface defects are found in the test process, the defects are removed by additional cutting and scraping of the front and rear ends, but when not found, the defects are delivered to the customer and cause an increase in defect rate and claims.

In the case of wire surface defects, the quality must be guaranteed up to 0.03mm or less. Therefore, visual inspection and quality inspection of the electric field are practically impossible. For this reason, the customer satisfaction with the surface quality among the wire rod product quality is relatively low. In particular, since the quality of the front and rear ends of the product is poor, it is necessary to improve the stability of the wire rod rolling line.

The present invention improves the stability of the wire rod rolling line, and proposes a method capable of manufacturing the wire rod while maintaining the original family system regardless of the change in the wire rod size.

The wire rod manufacturing method of the present invention for solving the above problems is the rolling of the raw material is rolled through the rough mill (Roughness Mill, RM), intermediate sand rolling (IFM), finishing rolling (FM) and final rolling (RSM) step Process and a rolled material winding process of winding the rolled material, the finishing rolling (FM) and the final rolling (RSM) step is rolling by rolling only a part of the roll (roll).

The final rolling (RSM) step operates only a sizing mill (SM) step.

In the material rolling process, the final rolling (RSM) step rolls the material at a higher speed than when the RM (reducing mill) step and SM (sizing mill) are operated.

In the rolling material winding process, when the tail of the rolled material passes through the final rolling (RSM) step, the point of starting tail speed increase and the degree of speed increase are performed in the final rolling (RMM) step; It is different from when operating SM (sizing mill).

According to the wire rod manufacturing method of the present invention by the above solution, the length of the no-finch section that has impaired the stability of the wire rod rolling line can be solved by using a part of the finishing rolling (FM) step.

Moreover, according to the wire rod manufacturing method of this invention by the said solving means, by changing the speed | rate of a rolling process, the stability of the rolling process according to the change of the drive roll for wire rod rolling can be improved.

1 is a process diagram schematically showing a part of a wire rod rolling process to which the wire rod rolling method of the present invention is applied.
FIG. 2 is a flowchart illustrating a process of intermediate mirror rolling (IFM) to final rolling (RSM) of a 13 mm pass schedule according to the related art and the present invention.
3 is a diagram illustrating a case where a wound shape defect occurs in the wire rod rolling process to which the wire rod manufacturing method of the present invention is applied.
4 is an ODG analysis diagram analyzing the control logic improvement of the tail speed increase function of the final rolling step of the wire rod manufacturing method of the present invention.
FIG. 5 is a flowchart illustrating a process of intermediate-measuring rolling (IFM) to final rolling (RSM) of a 13 mm pass schedule according to one embodiment of the wire rod manufacturing method of the present invention and another embodiment to improve the same.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, in describing in detail the operating principle of the preferred embodiment of the present invention, if it is determined that the detailed description of the related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

In order to clearly illustrate the present invention, parts not related to the description are omitted, and like parts are denoted by similar reference numerals throughout the specification.

In addition, when a part is said to "include" a certain component, this means that it may further include other components, except to exclude other components unless otherwise stated.

1 is a process diagram schematically showing a part of a wire rod rolling process to which the wire rod rolling method of the present invention is applied.

Referring to FIG. 1, after the billet is heated in a heating furnace, a rough mill (not shown), an intermediate finishing mill (IFM) 15, a finishing mill (FM) 10, and a final rolling mill 20 ( RSM) is hot rolled while passing in sequence and then cooled to manufacture a wire rod.

That is, the billet is charged into a heating furnace, heated, then rough-rolled, and after rough-rolling, the raw material is intermediate sand-rolled (IFM).

Next, as shown in FIG. 1, the raw material is cooled in the 1st water cooling stand (preliminary water cooling stand) 30 provided in the inlet side of the finishing mill 10, and is rolled by the finishing mill 10. FIG.

Then, the raw material is cooled in the first and second water cooling zones 40 and 50 of the final mill inlet side disposed between the finishing mill 10 and the final mill 20.

Then, the raw material 2 which has passed through the final rolling mill 20 is cooled in the first and second water cooling stages 60 and 70 at the final mill exit side, and finally wound in the laying head 80, and the wound wire rod ( 2 ') is integrated into a wire coil 2''in a reform tube 92 via a transfer table 90 which is air cooled.

In particular, the wire rod rolling process mainly produces 5.5mm ~ 16mm size, and is operated in one family process by pass schedule. One-family method consists of the whole rolling process as one pass schedule, and when the product size is increased, the roll change time is reduced and roll operation is performed by removing the intermediate rolling (IFM) or finishing rolling (FM) roll to produce the desired size. It has several advantages in rolling process operation such as shortening of quantity.

However, referring to FIG. 2, as the size of the pass schedule increases, the distance from the intermediate mirror rolling (IFM) or finishing rolling (FM) stand to the final rolling (RSM) stand is increased. This can cause flow, rolling stock fluctuations, etc., which can degrade wire surface quality. In addition, filament rolling (FM) or final rolling (RSM) is a block rolling driven by a gear ratio in one motor, it is difficult to always measure the rolling changes, such as stock, causing the material flow during rolling.

Therefore, in order to improve the wire surface quality, it is necessary to reduce the distance from the intermediate mirror rolling (IFM) or finishing rolling (FM) stand to the final rolling (RSM) stand.

Therefore, the above problem can be solved by additionally inserting a roll into the IFM or FM, but this method causes an increase in additional cost and downtime because it results in breaking the one-family method which has many advantages in the operation of the pass schedule. .

FIG. 2 is a flowchart illustrating a process of intermediate mirror rolling (IFM) to final rolling (RSM) of a 13 mm pass schedule according to the related art and the present invention.

Referring to FIG. 2, in the conventional 13mm pass schedule a, the No pinch section reached 60M, but in the 13mm pass schedule b of the present invention, it can be seen that the No pinch section was reduced to 30M. As the no pinch section decreases, material flow and rolling stock fluctuations decrease, so that the wire surface quality can be improved.

Referring to FIG. 2, in order to reduce the No pinch section, the wire rod manufacturing method of the present invention includes a reduction mill (RM) step as a dummy in the final rolling RSM, so that there is no substantial rolling. The rolling step to be performed in the RM) process may be performed by driving some rolls of the finishing rolling (FM) step. For this reason, it is reduced from the driving roll of the finishing rolling (FM) stage to the front end of the sizing rolling (SM) stage from the intermediate rolling mill (IFM) stage to the front end of the final rolling (RSM) stage.

Cobble or disconnection during rolling may occur in the section between filament rolling (FM) and final rolling (RSM) step due to tension distribution error between the stand during the initial test of the pass schedule change according to the application of the wire rod manufacturing method of the present invention. Can be. This problem can be solved by supplementing the tension value between the stands.

In order to drive only some of the rolls in finishing rolling (FM) and final rolling (RSM), the rolls to be driven are sufficiently examined in the conventional pass schedule, and the rolls to be driven are selected. The problem of the size difference can be solved by the tension between the stands (working speed adjustment).

In particular, in order to drive only some of the rolls in finishing rolling (FM) and final rolling (RSM), the tension between the stands must be higher than the conventional level. The moving speed of the rolled material should be taken faster.

Table 1 shows the amount of weight reduction in the No pinch section for each wire size according to the embodiment to which the pass schedule of the present invention is applied.

Wire rod
size RM pile
Target Size Original pass Change pass Sasang Rolling
Existing Stock Sasang Rolling
Change stock No inch
Interval reduction 15-16 mm 15,15.5,16mm 17-> RSM 19-> SM 21.4 mm 16.9 mm -85.1kg 12-14mm 12.5,13mm 19-> RSM 21-> SM 16.9 mm 14.0mm -69.0kg 10 ~ 11mm 10,10.5mm 21-> RSM 23-> SM 14.0mm 11.2mm -14.0 kg 8-9mm 8 mm 23-> RSM 25-> SM 11.2mm 8.9 mm -8.6kg 6.5 ~ 7.5mm 6.5mm 25-> RSM 27-> SM 8.9 mm 7.0mm -5.2 kg

As the wire size decreases, the number of rolls driven in the filament rolling (FM) step increases, and the wire rod manufacturing method of the present invention increases the number of rolls driven in the filament rolling (FM) step by two more than the conventional one. If possible, the two rolls of the reduction mill RM stage are prevented from being driven.

It is clear that the reduction of the No pinch section occurs for each wire size.

3 is a diagram illustrating a case where a wound shape defect occurs in the wire rod rolling process to which the wire rod manufacturing method of the present invention is applied.

Referring to Figure 3 (a) to (c), it can be seen that the defect occurs in the winding shape according to the change in the diameter of the tail (tail) of the wire rod.

As the pass schedule by wire size changes, the control logic from rolling to cooling also needs to change. In the wire rolling process, there is a shear for improving tip insertability between 19 stands and 20 stands. The cutting signal of the shear is calculated based on the reference rolling speed for each wire size. However, as the rolling speed changed due to the change of the pass schedule, cobbles were generated due to a material cutting signal error.

The above Cobble can solve this problem by applying two control logics depending on whether a reduction mill (RM) roll is inserted.

This solved the problem of the rolling operation, but the winding shape problem due to the change in the rolling speed and the amount of tension occurred.

In wire rod mills, the final rolling (RSM) tail speed up function is used for winding shapes for sizes greater than 13 mm. Final rolling (RSM) tail speed increase function means that the diameter of the ring is reduced when winding the material tail by increasing the speed of the progressing material through increasing the final rolling (RSM) when passing through the final rolling (RSM).

6.5mm ~ 12.5mm, which does not use the final rolling (RSM) tail speed increase function, can solve the problem of winding shape by adjusting the amount of tension and changing the operation method. However, in the case of 13 mm to 16 mm using the final rolling (RSM) tail speed increase function, a winding shape abnormality may occur at the time of increasing the rolling speed.

4 is an ODG analysis diagram analyzing the control logic improvement of the tail speed increase function of the final rolling step of the wire rod manufacturing method of the present invention.

Referring to FIG. 4, an additional control logic change through ODG analysis may solve the winding shape abnormality problem.

Looking at the control logic of the tail speed increase function before improvement, it can be seen that the linear speed of the laying head (L / H, 80) does not follow the final roll (RSM) tail speed properly when the final rolling (RSM) tail speed is increased. have. If the linear velocity of the laying head 80 does not properly follow the final rolling (RSM) tail velocity, a wound shape abnormality occurs while the diameter of the wound wire is narrowed.

Thus, in order to improve this, the wire rod manufacturing method of the present invention accelerates the application time of the final rolling (RSM) tail speed increase and decreases the rate of increase, so that the linear speed of the laying head 80 increases the final rolling (RSM) tail speed. You can keep it running smoothly.

FIG. 5 is a flowchart illustrating a process of intermediate-measuring rolling (IFM) to final rolling (RSM) of a 13 mm pass schedule according to one embodiment of the wire rod manufacturing method of the present invention and another embodiment to improve the same.

Referring to Figure 5, according to another embodiment to improve the method of manufacturing the wire rod of the present invention, by rolling in the roll located at the rear end in the finishing rolling (FM) step, the length of the No pinch section is reduced.

Examination of the stand-to-stand rolling ratio of the filament rolling (FM) step, which is the block rolling step, confirms that the roll diameters and gear ratios of the 20, 21 stand and the 22, 23 stand are the same. Therefore, it is possible to achieve an additional pass schedule improvement by using 22 and 23 stands instead of 20 and 21 stands for 12.5 to 13 mm products having 20, 21 stands. When further pass schedule is improved, the No Pinch generation section is reduced, and the power consumption in the filament rolling (FM) stage can be reduced by using 22-23 stands with relatively low motor deceleration ratio.

Table 2 shows the amount of weight reduction when using the wire rod manufacturing method according to the existing, one embodiment (A) and another embodiment (B) of the present invention.

Application method Pass schedule Rolled stock No Pinch Distance No inch
Section weight Weight loss existing 19-> SM 16.9 mm 60 m 105.6 kg A 21-> SM 14.0mm 30 m 36.0 kg -69.0kg B 23-> SM 14.0mm 28 m 33.6 kg -2.8 kg

As described above, it was possible to establish a reduction mill (RM) dummy rolling method of the final rolling (RSM) facility by improving the overall control logic and operation method from the rolling process to the cooling process. In addition to improving wire surface quality, the reduction mill (RM) pile rolling method can reduce the load of the final roll (RSM) roll replacement, which requires three hours of work by three workers, and reduce the risk of safety accidents due to roll replacement operations on the rolling line. have. In addition, the power consumption was reduced by reducing the operation rate of high-load equipment, final rolling (RSM).

In the wire rod rolling method of the present invention, the discharge amount and the gear ratio are examined in the pass schedule, and the reduction mill (RM) is piled in the final rolling (RSM), and the rolling is performed using intermediate sand rolling (IFM) or finishing rolling (FM). Do it. In addition, the rolling operation is possible by adjusting the tension between the stands (rolling speed adjustment) so that the smooth rolling process is performed in the above configuration. That is, the wire rod rolling method of the present invention establishes a reduction mill (RM) dummy rolling technology by proposing the entire control logic and operation method from rolling to cooling.

In addition, reduction mill (RM) roll replacement loads (three people take about two hours) and reduction of the risk of safety accidents due to roll replacement operations on the rolling line can be achieved through reduction mill (RM) pile operations. By reducing the operation rate of the final rolling (RSM) can reduce the power consumption.

By applying the wire rod manufacturing method of the present invention to the wire rod rolling process, the surface flaw detection rate, the customer claim rate, the wire rod surface crack factor scrap incidence rate can be reduced by half. In addition, it was possible to reduce the risk of safety accidents due to the reduction of the roll replacement load and the roll replacement in the rolling line.

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and it is common in the art that various substitutions, modifications, and changes can be made without departing from the technical spirit of the present invention. It will be apparent to those skilled in the art.

2: material 2 ': wound material
2 '': small diameter wire rod coil
10: finishing rolling (FM) 15: intermediate rolling (IFM)
20: final rolling (RSM) 30, 40, 50, 60, 70: water cooling stand
80: laying head 90: transfer table
92: accumulator

Claims (4)

Rolling the heated material through the roughness mill (Roughness Mill), intermediate sand roll (IFM), finishing rolling (FM) and final rolling (RSM) step; And
Including a rolling material winding process for winding the rolled material,
The finishing rolling (FM) and the final rolling (RSM) step is a wire rod manufacturing method of rolling by rolling only a part of the roll. The method of claim 1, wherein the final rolling (RSM) step operates only a sizing mill (SM) step.
The method of claim 2, wherein the material rolling process
A method of manufacturing wire rods in which the final rolling (RSM) step rolls the material at a higher speed than when operating both the reducing mill (RM) step and the sizing mill (SM) step.
According to claim 3, wherein the rolled material winding process
When the tail rolling of the rolled material passes the final rolling (RSM) step, the tail speed increases rather than when the final rolling (RSM) step operates both the reduction mill (RM) step and the sizing mill (SM) step. A method for manufacturing wire rods that speeds up the time and slows down the rate of increase.

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