KR20120097185A - Apparatus for fabricating tailored rolled blank and method for fabricating tailored rolled blank using the same - Google Patents

Abstract

PURPOSE: A TRB(Tailored Rolled Blank) manufacturing apparatus and method are provided to increase unit per hour by allowing for the maximum reduction rate of 60% to freely control the thickness of TRB. CONSTITUTION: A TRB manufacturing method is as follows. A TRB rolling process is implemented using a hot rolled coil(170) at a temperature equal to or higher than the temperature of a hot rolled coil, 400-500°C, after completion of a hot rolling process. A blank obtained through the TRB rolling process varies in thickness.

Description

TV manufacturing apparatus and manufacturing method for TV using the same {APPARATUS FOR FABRICATING TAILORED ROLLED BLANK AND METHOD FOR FABRICATING TAILORED ROLLED BLANK USING THE SAME}

The present invention relates to a TRB (Tailored Rolled Blank) manufacturing apparatus and a TRB manufacturing method using the same, and more particularly, by using a high-strength steel sheet using a thermal insulation box in the manufacturing process, rolling while maintaining the temperature of the hot rolled coil The present invention relates to a technology for making this easy, reducing the rolling load, and enabling TRB rolling even with a thin steel sheet having a thickness of 0.8 mm.

The manufacturing method of Tailored Rolled Blank (TRB) for weight reduction among automotive steel sheets is a material processing method for re-rolling steel sheets having a tensile strength of 440 MPa or less at a certain interval at room temperature so that the thicknesses appear in one blank differently. .

An object of the present invention is to produce a high-strength steel sheet with a tensile strength of 540 MPa or more in TRB, using the point that the temperature in the wound state after hot rolling is 400 ~ 500 ℃ or more, immediately re-rolled in the state where the high strength steel sheet is wound after rolling It is to provide a method for the TRB manufacturing process to proceed through.

To this end, an object of the present invention is to provide a TRB thermal insulation box for maintaining the temperature of the coil around the TRB rolling roll portion in which the TRB manufacturing process is performed. In addition, an object of the present invention is to provide a separate thermal insulation box that can store the hot rolled coil and TRB coil to be TRB.

TRB manufacturing method according to an embodiment of the present invention by using a hot rolled coil, the hot rolling process is completed, performing a TRB (Tailored Rolled Blank) rolling process so that the thickness appears in one blank (Blank), the TRB rolling process is characterized in that carried out at a temperature higher than the temperature of the hot rolled coil in the state that the hot rolling process is completed.

Here, the hot rolling coil is 400 ~ 500 ℃ of the hot rolling state is completed, the TRB rolling process is characterized in that using the TRB insulation box surrounding the entire area where the TRB rolling process is performed.

In addition, the TRB manufacturing apparatus according to an embodiment of the present invention using a hot rolled coil, the rolling roll portion for performing a rolling rolled blank (TRB) rolling process so that the thickness appears in one blank (Blank) differently and the rolling It is provided in a form surrounding the roll portion and the entire hot rolled coil, characterized in that it comprises a TRB insulation box to maintain the temperature of the hot rolled coil in a state where the hot rolling process is completed.

At this time, the TRB thermal insulation box is provided at the entrance side and opened when the hot rolling coil in the state where the hot rolling process is completed is opened, and is provided at the exit side when the hot rolled coil in the state where the TRB rolling process is completed is discharged. An open coil outlet may be formed.

When manufacturing the TRB of the high strength steel sheet using the TRB manufacturing method according to the present invention, it is possible to solve the problem that the work load is significantly reduced because the rolling load is too high according to the tensile strength of the high strength steel sheet.

In addition, the present invention provides an effect of freely adjusting the thickness of the TRB by providing a reduction ratio of up to 60% when the existing TRB manufacturing method can be processed at a reduction ratio of up to 30%.

Therefore, the present invention provides an effect that can increase the production per hour by 3 to 4 times the existing TRB.

In addition, the present invention provides the effect of saving the energy required for heat treatment because the re-rolling proceeds directly in the rolling winding machine does not need a separate heat treatment process.

In addition, the present invention reduces the fatigue of the rolling roll portion by less load on the rolling roll portion, and provides the effect of extending the service life of the equipment for a longer time.

1 is a graph showing the relationship between the temperature and tensile strength of a hot rolled steel sheet for a method of manufacturing TRB according to an embodiment of the present invention.
2 is a cross-sectional view schematically showing a TRB manufacturing apparatus according to an embodiment of the present invention.
3 and 4 is a schematic view showing a TRB manufacturing apparatus according to another embodiment of the present invention.
5 is a schematic view showing a front side member manufactured by molding the TRB according to the present invention.

Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. It should be understood, however, that the invention is not limited to the disclosed embodiments, but is capable of many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, To fully disclose the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout the specification.

In addition, the blank (Blank) generally refers to the steel sheet processed to fit the size of the press mill as in the hot stamping process, but in the present invention it is to refer to all cases provided in the form of a coil before processing. .

Hereinafter, a TRB manufacturing apparatus and a TRB manufacturing method using the same according to a preferred embodiment of the present invention with reference to the accompanying drawings in detail as follows.

1 is a graph showing the relationship between the temperature and tensile strength of a hot rolled steel sheet for a method of manufacturing TRB according to an embodiment of the present invention.

Referring to Figure 1, it can be seen that the tensile strength (TS) at a high temperature of 400 ℃ or more appears to be less than 300MPa.

That is, even at high temperature, even when the high-strength steel sheet having a tensile strength of 540 MPa or more, when heated to 400 ° C. or more, the tensile strength is reduced to 300 MPa or less, and the load applied to the rolled roll portion is reduced.

Therefore, in the present invention, the re-rolling process for controlling the thickness of the TRB is performed at a temperature of 400 ° C. or more, but rather than adding a separate heating apparatus to the TRB manufacturing apparatus, the hot rolled steel sheet itself temperature after the end of hot rolling can be used. Make sure

At this time, the high strength steel sheet having a tensile strength of 540 MPa or more is usually 400 to 500 ° C. or more, except for some martensitic steels, in which the temperature is wound after rolling.

Therefore, the high-strength steel sheet is to be carried out in the TRB manufacturing process through re-rolling immediately after the rolled state, in the present invention to maintain the self-temperature of the hot-rolled coil by using a thermal insulation box using a heat insulating material.

2 is a cross-sectional view schematically showing a TRB manufacturing apparatus according to an embodiment of the present invention.

Referring to FIG. 2, first, a rolling roll 160 for performing a TRB rolling process is provided in a central portion. The TRB object coil 150 passes through the rolling roll unit 160 while being uncoiled. The steel sheet in the uncoiled state where the TRB rolling process is completed by passing through the rolling roll unit 160 may be wound again to form a TRB coil form 170.

Here, the region from the TRB target coil 150 to the TRB coil 170 including the rolling roll unit 160 may be defined as a 'region where the TRB rolling process is performed'.

At this time, the actual TRB manufacturing apparatus, including a rolling thickness adjusting unit 180, a complex mechanical device such as a roller table or a coil fixing device will be required, but in the present invention will be omitted for convenience of description. Therefore, the present invention is not limited by the configurations of the TRB manufacturing apparatus, which is not shown.

In addition, the present invention is provided in a form surrounding the entire area where the TRB rolling process is performed, so that the temperature of the TRB target coil 150 and the TRB coil 170 can be maintained even during the TRB rolling process. TRB thermal insulation box 100 is provided.

TRB insulation box 100 according to the present invention may be provided differently according to the scale of the TRB manufacturing equipment. Although it is shown that it has a simple box shape, in fact, it may be provided in any one of a spherical shape, a pyramidal shape and a cylindrical shape, it may be provided in various forms.

In addition, the TRB thermal insulation box 100 according to the present invention may be provided in the form of a structure using a building insulation.

At this time, in order for the TRB target coil 150 to be mounted inside the TRB insulation box 100, a coil inlet portion 110 is formed at an entrance side of the TRB insulation box 100, and the coil inlet portion 110 is formed. Coil discharge portion 120 may be formed on the exit side to be symmetrical.

In order to maintain the temperature, the coil inlet 110 may be opened only when the hot rolled coil in which the hot rolling process is completed is introduced. In addition, the coil outlet 120 may be opened only when the hot rolled coil in a state where the TRB rolling process is completed is discharged.

Here, the coil inlet 110 and the coil outlet 120 shown in the figure is only a representative example of the entrance and exit device is not limited thereto.

As described above, the TRB thermal insulation box 100 of the TRB manufacturing apparatus according to the present invention is provided, and when using the TRB manufacturing apparatus according to the present invention, even in the case of high-strength steel sheet is hardly affected by the rolling load, various thicknesses Can produce TRB of.

In addition, in the present invention, in order to improve TRB manufacturing efficiency, a hot rolled coil insulation box for preventing temperature loss that may occur when the TRB target coil 150 is moved may be further provided.

3 and 4 is a schematic view showing a TRB manufacturing apparatus according to another embodiment of the present invention.

First, referring to FIG. 3, it can be seen that the hot rolling process is classified into a general coil 240 and a TRB target coil 250.

At this time, in the present invention, to maintain the temperature of the TRB target coil 250, a coil carrying insulation box 260 manufactured in a box shape using a heat insulating material is used.

In addition, as long as the coil carrying insulation box 260 according to the present invention can wrap the TRB object coil 250, it may be provided in any form.

Here, the hot rolling process for the final temperature of the TRB target coil 250 to be represented to 400 ~ 500 ℃ can be described as follows.

First, the hot rolled slab 200 according to the present invention is reheated at a temperature of 1150 ~ 1250 ℃. At this time, if the reheating temperature is less than 1150 ℃ slab 200 surface properties are deteriorated may be not rolling normally. On the contrary, when the slab reheating temperature exceeds 1250 ° C., the austenite grain size may increase to increase the ferrite of the final microstructure, thereby making it difficult to secure the strength, and the manufacturing cost of the steel sheet may increase due to the excessive heating process.

Next, the slab 200 is finish-rolled to 750 ~ 850 ℃ while passing through the finishing rolling section 210. At this time, when the finish rolling temperature exceeds 850 ° C the austenite grains are coarsened and the ferrite grains are not sufficiently refined after the transformation, thereby making it difficult to secure the strength. In addition, when the finishing rolling temperature is too low below 750 ° C, problems such as generation of a mixed structure due to abnormal reverse rolling may occur.

Next, the hot rolled coil form is completed while continuously passing through the runout table portion 200 and the winding portion 230. At this time, the cooling and winding temperature is adjusted to 400 ~ 500 ℃. In the present invention, the cooling process is performed by hot-rolled sheet material through a method such as water cooling, when cooled and wound to less than 400 ℃ to suppress the grain growth of the steel sheet to form a matrix having fine ferrite grains, and also pearlite Forming tissue can make it difficult to secure high strength and toughness. On the contrary, when cooled and wound to a temperature exceeding 500 ℃, there is no particular limitation, but the strength may be insufficient.

Next, the TRB object coil 250 passes through the TRB rolling roll to form a final TRB shape, which will be described with reference to FIG. 4.

Referring to FIG. 4, the TRB object coil 300 finally formed by the hot rolling process is connected to the TRB insulation box 350 in a form put in the coil transport insulation box 310.

Next, in the TRB insulation box 350, the TRB target coil 300 passes through the rolling roll part 330 to have a final TRB shape, and the TRB is wound in the coil 320 again.

At this time, the temperature inside the TRB thermal insulation box 350 is preferably maintained at 400 ℃ or more. To this end, the present invention monitors the temperature inside the TRB thermal insulation box 350 as necessary, and if the monitored temperature is less than 400 ° C., an auxiliary heating unit capable of maintaining the temperature by a method such as ultrasonic induction heating or hot air generation ( 360) may be further included.

Next, the completed TRB coil 320 is discharged from the TRB insulation box 350, and is subjected to a separate stress relief (Stress Relief) process. At this time, in the present invention, by using the stress-retaining thermal insulation box 340 similar to the coil transporting thermal insulation box, the stress relief process can be easily performed without special reheating.

At this time, it is preferable that the temperature difference between the TRB target coil 300 and the TRB coil 320 does not exceed 100 ° C. When the temperature difference exceeds 100 ° C., the TRB rolling efficiency may be lowered and the characteristics of the completed TRB may be lowered.

As described above, in the case of using the TRB manufacturing method and apparatus according to the present invention, even when using a high-strength hot-rolled steel sheet can be efficiently completed TRB, as shown in Figure 5 below.

5 is a schematic view showing a front side member manufactured by molding the TRB according to the present invention.

FIG. 5 shows a front side member (Front Side Member, 400) manufactured by manufacturing a TRB obtained by rolling the thickness of the steel sheet to 2.0 mm, 1.4 mm, and 0.8 mm using the above-described TRB manufacturing method. .

In this case, in the case of the front side member, which must have excellent front impact characteristics, the front collision part 410 must maintain a thin thickness of 0.8 mm, and the middle bend part 420 must satisfy a thickness of 1.4 mm, and a cabin (Cabin) The part shall satisfy the thickness of 2.0mm.

Here, since the room temperature elongation of the high strength steel sheet is 25 to 30%, when using the existing room temperature TRB process, only a maximum reduction rate of 30% could be implemented. Therefore, there was a limit that the steel sheet for TRB of 2.0 mm is produced only up to 1.4 mm.

However, according to the present invention, in the case of a high strength steel sheet at a high temperature of 400 ~ 500 ℃ more than the tensile strength falls to 100 ~ 300MPa, the elongation is also increased to 40 ~ 60%. Therefore, when using the TRB insulation box according to the present invention is less rolling load, workability is improved, 2.0 mm steel sheet can be pressed down to a maximum of 0.8 mm.

That is, in the case of the front side member according to the present invention, it may be possible to reduce the weight by about 30% than the product made of only the heterogeneous thickness of 2.0mm and 1.4mm.

Thus, hourly production can be three to four times higher than conventional TRB manufacturing. In addition, since the rolling can proceed in the TRB insulation box immediately after the rolling winding is completed, the temperature of the initial hot rolled coil is maintained as it is. Therefore, it is possible to save the heat treatment energy for stress relief and the like, and it is possible to use the TRB manufacturing apparatus for a longer time by reducing the fatigue degree of the rolling roll part with less rolling load.

While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments. Such changes and modifications are intended to fall within the scope of the present invention unless they depart from the scope of the present invention. Accordingly, the scope of the present invention should be determined by the following claims.

100, 350: TRB insulation box 110: coil inlet
120: coil outlet 150, 250, 300: TRB target coil
160: rolled roll portion 170, 320: TRB coil
180: thickness control 200: slab
210: filament rolling part 220: runout table part
230: winding-up 240: general coil
260, 310: coil carrying insulation box 340: stress relief insulation box
360: auxiliary heating unit 400: front side member
410: front impact portion 420: intermediate bending portion
430 cabin part

Claims (11)

Using a hot rolled coil having completed the hot rolling process, a tailed rolled blank (TRB) rolling process is performed in which a thickness appears differently in one blank.
The TRB rolling process is a TRB manufacturing method, characterized in that carried out at a temperature equal to or higher than the temperature of the hot rolled coil in the state that the hot rolling process is completed.
The method of claim 1,
The temperature of the hot rolled coil in the state where the hot rolling process is completed
TRB production method, characterized in that 400 ~ 500 ℃.
The method of claim 1,
Before the TRB rolling process,
In order to maintain the temperature of the hot rolled coil, TRB manufacturing method characterized by using a coil carrying insulation box.
The method of claim 1,
The TRB rolling process
TRB manufacturing method characterized in that using the TRB thermal insulation box covering the entire area where the TRB rolling process is performed.
The method of claim 1,
After the TRB rolling process
TRB manufacturing method characterized in that the stress relief (Stress Relief) of the coil is completed using the stress-retaining thermal insulation box.
The method of claim 1,
The TRB rolling process
TRB production method characterized in that the reduction is carried out at 60% or less.
A rolling roll unit for performing a tail rolled blank (TRB) rolling process in which a thickness appears differently in one blank by using a hot rolled coil; And
And a TRB insulation box provided in a form surrounding the rolling roll unit and the entire hot rolled coil to maintain a temperature of the hot rolled coil in a state in which the hot rolling process is completed.
The method of claim 7, wherein
In the TRB insulation box
A coil inlet part provided at the inlet side and opened when the hot rolled coil in the state where the hot rolling process is completed is introduced;
TRB manufacturing apparatus characterized in that the coil discharge portion provided on the exit side is opened when the hot rolled coil of the TRB rolling process is completed is discharged.
The method of claim 7, wherein
The TRB manufacturing apparatus
And a coil insulation box for maintaining a temperature while transferring the hot rolled coil in which the hot rolling process is completed to the TRB insulation box.
The method of claim 7, wherein
The TRB manufacturing apparatus
TRB manufacturing apparatus characterized in that it further comprises a stress-retaining thermal insulation box provided to perform a stress removal process, while maintaining the temperature of the TRB coil manufactured by passing through the TRB rolling roll.
The method of claim 7, wherein
The TRB manufacturing apparatus
TRB manufacturing apparatus characterized in that it further comprises an auxiliary heating unit for maintaining the temperature inside the TRB insulation box at 400 ℃ or more.

Images