KR20130107493A - Hot forming and variable thickness stamping - Google Patents

Abstract

PURPOSE: A hot-stamping molding method including thickness treatment is provided to manufacture a component which has locally different strength as a blank of regular thickness locally has different thickness by locally hot-rolling blanks. CONSTITUTION: A hot-stamping molding method including thickness treatment includes the following steps of: arranging a blank having regular thickness; and forming a shape of the blank by using a press device and reducing the thickness of a part of the blank by hot-rolling. The press device is divided into a hot-rolling press mold (210) and a cold-rolling press mold (220).

Description

HOT FORMING AND VARIABLE THICKNESS STAMPING}

The present invention relates to a hot stamping molding method for forming a press material from a blank material, and more particularly, the blank material is locally heated and then molded, and the heated part is locally formed by a thickness processing to reduce the thickness. The present invention relates to a hot stamping molding method capable of manufacturing parts having different thicknesses.

Vehicles with various strengths are used. For example, parts that need to absorb energy when colliding or overturning the vehicle are required to have relatively weak strength, and strong strength is required in parts where shape maintenance is required in order to secure a passenger's living space.

In the event of a collision where energy is absorbed too high, the shock energy will not be absorbed properly and will be transferred to the other parts, which will result in an excessive impact on the passengers and other parts of the vehicle.

Some sections of the component require high strength to protect occupants, but some sections require relatively low strength to absorb impact energy.

Vehicles are constantly required to be lightweight and cost-saving. Accordingly, parts can be manufactured with heterogeneous strength by allowing one part to have different dissimilar thicknesses.

Conventionally, a component having heterogeneous strength was manufactured by using a Taylor Welded Blank, which is formed by welding blanks having different thicknesses. .

Related prior art is Korean Patent Publication No. 10-2011-0056888 (published May 31, 2011) 'Taylor welded hot stamping manufacturing method and a molded article having a local heterogeneous strength using the same.

SUMMARY OF THE INVENTION An object of the present invention is to provide a hot stamping molding method which can produce a component having a locally dissimilar thickness by heating a blank material having a single thickness locally in a fleece device and reducing the thickness by hot forming some regions. In providing.

The present invention for achieving this object, the blank preparation step of providing a blank having a uniform thickness; And forming a shape of the blank in a press apparatus, wherein a partial region is press-molded to reduce the thickness by hot forming.

Preferably, the press apparatus used in the press molding step is divided into a hot press mold for processing a shape and a thickness, and a cold press mold for processing a shape of an unheated portion.

The hot press mold is more preferably heated to maintain a temperature of 400 ~ 500 ℃ during press molding, the cold press mold is cooled to maintain a room temperature state during press molding.

In addition, it is preferable to vary the pressing force of the hot press mold and the cold press mold.

On the other hand, the hot press mold or the cold press mold is preferably provided with a heat insulating layer on the part facing the other mold,

The hot forming region is heated by a hot press mold.

In addition, the thickness reduction due to the hot forming is preferably in the range of 10 to 20%.

The hot stamping molding method according to the present invention has the effect of locally hot forming using a blank having a uniform thickness, thereby producing a component having heterogeneous strength by having a locally different thickness of the molded article.

1 is a process flow chart of a hot stamping molding method comprising a thickness processing according to the present invention;
2 is a view showing the configuration of a press apparatus for a hot stamping molding method including a thickness processing according to the present invention,
3 is a configuration diagram showing a state in which a blank is loaded in the press apparatus for the hot stamping molding method including the thickness processing according to the present invention,
4 is a view showing the configuration of a press apparatus for a hot stamping molding method including a thickness processing according to another embodiment of the present invention.

Hereinafter, an embodiment of a local heating apparatus and a hot stamping molding method using the same will be described with reference to the accompanying drawings.

In this process, the thicknesses of the lines and the sizes of the components shown in the drawings may be exaggerated for clarity and convenience of explanation.

In addition, the terms described below are defined in consideration of the functions of the present invention, which may vary depending on the intention or custom of the user, the operator.

Therefore, definitions of these terms should be made based on the contents throughout the specification.

1 is a process flow diagram of a hot stamping molding method comprising a thickness processing according to the present invention.

The present invention provides a method capable of producing a thickness having a heterogeneous thickness into a blank having a uniform thickness.

For example, if a part has a part requiring a thickness of 1.2 mm and a part requiring a thickness of 1.0 mm, conventionally, a 1.2 mm thick blank and a 1.0 mm thick blank are cut, and then welded with a laser to weld the tailor welded. The blank was manufactured and then molded in a press. When using the hot stamping molding method according to the present invention, after forming the entire blank having a thickness of 1.2 mm, the part requiring 1.0 mm thickness at the time of press working was pressed to have a thickness of 1.0 mm. To be processed to be.

As shown, the hot stamping molding method comprising a thickness processing according to the present invention, the blank preparation step (S-11) for providing a blank having a uniform thickness and the blank is molded in the press apparatus, Some areas include a press forming step (S-12) to reduce the thickness by hot forming.

In the blank preparation step (S-11), a steel sheet corresponding to the thickness of the thick part of the molded product is cut to prepare a blank. The invention is not to use a tailored welded blank but to process it to have a locally different thickness using a general blank with a uniform thickness.

Press molding step (S-12) is to form a blank having a uniform thickness by using a press apparatus, but to perform the local thickness processing with the processing of the overall shape.

In order to reduce the thickness of the blank, a greater pressure is required than in the processing of the shape. In the present invention, a portion where the thickness is changed after locally heating a portion where the thickness is processed is processed by hot forming.

That is, in one blank, some regions process the thickness and the shape through hot forming, and parts where the change of the thickness is not necessary are processed only by the cold forming.

The local heating of the hot forming region may be made by a press apparatus, or may be processed in the press apparatus after the blank is locally heated in advance using a separate apparatus.

It is preferable that the thickness process by this invention is a range which reduces 10-20% of thickness. Reduction of less than 10% of the thickness is not very helpful to the heterogeneous strength or light weight of the part, and if the thickness is reduced by more than 20%, it is difficult to obtain the desired physical properties by changing the microstructure of the thickness processing site.

However, in some cases, the thickness may be reduced by more than 20%. For example, it may be necessary to intentionally change the microstructure, or if the effect of work hardening can be reduced to 50% thickness exceeding 20%.

2 is a view showing the configuration of a press apparatus for a hot stamping molding method including a thickness processing according to the present invention, Figure 3 is a blank in a press apparatus for a hot stamping molding method including a thickness processing according to the present invention A diagram showing the loaded state.

As shown, the press apparatus for the hot stamping molding method including the thickness machining according to the present invention processes one blank B in two divided press molds. That is, the press apparatus for the present invention is divided into a hot press mold 210 for processing the thickness and shape of the portion requiring the thickness processing, and a cold press mold 220 for processing the shape. The divided hot press mold 210 and the cold press mold 220 simultaneously process one blank B, whereby the pressing force applied to the blank B may be different from each other.

Since the pressure required for processing the thickness and the pressure for processing only the shape is different, it is divided into the hot press mold 210 and the cold press mold 220, so that different pressing pressures can be given for each part.

The hot press mold 210 is provided with a heating means to maintain the hot press mold a constant temperature, the cold press mold 220 is provided with a cooling means to maintain the cold press mold 220 at room temperature It is preferable. Here, the room temperature means a general atmospheric temperature, in this specification, the room temperature means about 20 ~ 30 ℃.

However, the cold press mold 220 may receive heat from the hot press mold 210. Therefore, the cooling press mold 220 may vary in temperature in the range of ± 100 ℃ based on the room temperature.

When heated by the hot press mold 210 can be heated to a temperature about 100 ℃ higher than the normal temperature, if the cold press mold 220 is provided with a separate cooling means thereby cooling to a temperature about 100 ℃ lower than the room temperature May be

An electrothermal heater or a circulating thermal fluid may be used as a heating means of the hot press mold 210. In the case of using an electric heater or a heat fluid, the temperature of the entire hot press mold 210 is raised to a predetermined range, and the loaded blank material receives heat from the hot press mold 210 during the processing and is heated to have a thickness processing. Will be done.

Alternatively, an induction heating coil may be used as a heating means of the hot press mold 210. In the case of using an induction heating coil, when the hot press mold 210 is formed of a non-conductive material, only the blank material may be heated without heating the hot press mold 210 itself. Of course, the hot press mold 210 may be formed of a conductive material so that the hot press mold 210 itself is heated by an induction heating coil.

The cold press mold 220 has a cooling means to offset the heat transferred from the hot press mold 210 or the blank, a refrigerant circulating to the cooling means may be used.

Hot press mold 210 is preferably maintained at a temperature of 400 ~ 500 ℃. If the temperature of the hot press mold is less than 400 ℃ excessive pressure is required for the thickness processing, the hot press mold consumes excessive energy (power) to maintain the temperature above 500 ℃.

However, when the workpiece is soft or has a relatively low melting temperature, it may be sufficient that the hot press mold 210 has a temperature of 100 ° C or higher.

4 is a view showing the configuration of a press apparatus for a hot stamping molding method including a thickness processing according to another embodiment of the present invention.

In this embodiment, the cold press mold 220 and the hot press mold 210 to form a heat insulating layer (215, 225) facing each other, the heat of the hot press mold 210 is transferred to the cold press mold 220. By being blocked, the energy consumed for heating the hot press mold 210 and the energy consumed for cooling the cold press mold 220 can be reduced. In the illustrated embodiment, although both the hot press mold 210 and the cold press mold 220 are provided with a heat insulating layer, the heat insulating layer may be provided only on one side.

As described above, the hot stamping molding method including the thickness processing according to the present invention enables the production of parts having locally different thicknesses using a single blank having a uniform thickness. Therefore, there is no welding part in the part, so there is no quality problem due to the welding part, and laser processing is not used, so the process time is short and the cost is low.

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. It will be understood that the invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive.

B: blank
210: hot press mold
215, 225: heat insulation layer
220: cooling press mold

Claims (7)

A blank preparing step of preparing a blank having a uniform thickness; And
And forming a blank in a press apparatus, wherein a part of the blank is pressed to reduce the thickness by hot forming.
The method of claim 1,
The press apparatus used in the press molding step is
Hot press mold for processing shape and thickness,
The hot stamping molding method, characterized in that divided into a cold press mold for processing the shape of the unheated portion.
3. The method of claim 2,
The hot press mold is heated to maintain a temperature of 400 ~ 500 ℃ during press molding,
The cold press mold is hot stamping molding method characterized in that the cooling to maintain a room temperature state during the press molding.
3. The method of claim 2,
Hot stamping molding method characterized in that the pressing force between the hot press mold and the cold press mold.
3. The method of claim 2,
The hot press mold or the cold press mold hot stamping molding method characterized in that it comprises a heat insulating layer on the portion facing the other side mold.
3. The method of claim 2,
And the hot forming region is heated by a hot press mold.
The method of claim 1,
The thickness reduction due to the hot forming
Hot stamping molding method, characterized in that 10 to 20% range.

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