KR102395531B1 - Method of manufacturing door impact beam by using doubled steel pipe and door impact beam manufactured of the same - Google Patents

Abstract

The present invention prepares an inner tube 110 of a first diameter through a drawing process of a first metal material (S110), and an outer tube 120 of a second diameter through a drawing process of a second metal material step (S120), preparing a double steel pipe pipe by inserting the inner pipe 110 inside the outer pipe 120 (S130), inserting the double steel pipe pipe into the ram and extruding it (S140), extruding from the ram Heat-treating the double steel pipe to be used at 150° C. to 1350° C. (S150), drawing the heat-treated double steel pipe in a straight shape to form a specific shape (S160), and cutting the pultruded double steel pipe to a certain length Disclosed is a method for manufacturing a door impact beam using a double steel pipe, including the step of cutting (S170), for manufacturing a door impact multi-pipe beam with good bonding strength and tensile strength of the double steel pipe.

Description

Method of manufacturing a door impact beam using a double steel pipe and a door impact beam manufactured thereby

The present invention relates to a method for manufacturing a door impact beam using a double steel pipe, which can improve strength, reduce manufacturing cost, and realize weight reduction by composing a double pipe with a carbon steel pipe and an aluminum steel pipe, and a door impact beam manufactured by the method.

In general, a door impact beam is applied as a shock supplement that absorbs impact energy during a side impact to minimize injuries to occupants, and is also manufactured from a single aluminum steel tube.

However, the door impact beam made of a single aluminum steel tube is generally manufactured to a thickness of 5 mm or more, thereby increasing manufacturing cost and poor strength.

A multi-tube beam is sometimes applied to complement the single-tube structure. A general multi-tube beam is manufactured by a shrink fit method using an adhesive or a difference in thermal expansion coefficient, or metallurgical bonding, mechanical bonding, and thermal bonding. (thermal bonding)

On the other hand, by the hydraulic pressure by the hydroforming method, a double pipe coupled in a loose state is inserted in a mold with a gap between the inner circumferential surface of the outer tube and the outer circumferential surface of the inner tube, and then high-pressure hydraulic pressure is applied to the inside of the tube with the mold closed. Although the inner tube expands by hanging and a double tube is manufactured, there is a possibility of structural deformation and there is a limit to manufacturing a multi-pipe with high tensile strength desired by consumers without pre-treatment of the pipe. do.

Korean Patent Publication No. 10-1590021 (Multi-pipe manufacturing apparatus and multi-pipe manufacturing method using the same, 2016.02.01) Korean Patent Publication No. 10-1551076 (Vehicle impact beam and its manufacturing method, 2015.09.07) Korean Patent Publication No. 10-2020-0050239 (Door impact beam manufacturing method and door impact beam, 2020.05.11)

The technical problem to be achieved by the spirit of the present invention is a method for manufacturing a door impact beam using a double steel pipe, which can be configured with a carbon steel pipe and an aluminum steel pipe to improve strength, reduce manufacturing cost, and realize weight reduction, and manufacturing thereby It is to provide a door impact beam that is

In order to achieve the above object, the present invention comprises the steps of: preparing an inner tube of a first diameter through a drawing process of a first metal material; preparing an outer tube of a second diameter through a drawing process of a second metal material; preparing a double steel pipe by inserting the inner tube inside the outer tube; inserting the double steel pipe into a ram and extruding it; heat-treating the double steel pipe extruded from the ram at 150° C. to 1350° C.; forming a specific shape by drawing the heat-treated double steel pipe pipe into a straight shape; and cutting the pultrusion-formed double steel pipe pipe to a predetermined length; to provide a door impact beam manufacturing method using a double steel pipe, including a; .

On the other hand, the first metal material is carbon steel, the second metal material is made of aluminum steel, and the step of preparing the inner tube is 800 ℃ to 1100 ℃ 1 second to 5 Heat treatment by high-frequency induction heating for seconds, primary quenching heat treatment of quenching to 250° C. or lower within 5 sec, tempering at 200° C. to 700° C. for 30 minutes to 3 hours, and then the drawing process It may be configured to prepare an inner tube of a first diameter through.

Here, in the step of preparing the inner tube, after performing the first quenching heat treatment, heat treatment is further performed by high-frequency induction heating at 800° C. to 1100° C. for 1 second to 5 seconds, and to 250° C. or less within 5 sec. After further performing the secondary quenching heat treatment for quenching treatment, after performing tempering at 200 ° C to 700 ° C for 30 minutes to 3 hours, it may be configured to prepare an inner tube of the first diameter through a drawing process .

Alternatively, the first metal material is aluminum steel, the second metal material is carbon steel, and the step of preparing the outer tube is to heat the tubular second metal material at 800°C to 1100°C for 1 second to 5 seconds. Heat treatment by high-frequency induction heating for seconds, primary quenching heat treatment of quenching to 250° C. or lower within 5 sec, tempering at 200° C. to 700° C. for 30 minutes to 3 hours, and then the drawing process It may be configured to prepare an outer tube of a second diameter through the.

Here, in the step of preparing the outer tube, after performing the first quenching heat treatment, heat treatment is further performed by high-frequency induction heating at 800° C. to 1100° C. for 1 second to 5 seconds, and to 250° C. or less within 5 sec. After further performing the secondary quenching heat treatment of quenching treatment, after performing tempering at 200 ° C to 700 ° C for 30 minutes to 3 hours, it may be configured to prepare an outer tube of a second diameter through a drawing process .

In addition, through the in-line facility, immediately after the first quenching heat treatment, the second quenching heat treatment can be continuously batch-processed.

In addition, the double steel pipe pipe may be formed by drawing it into a circular, oval, or polygonal cross-sectional shape.

In addition, the method may further include processing the cut double steel pipe pipe into a curved shape by die quenching, forming, or bending to match the shape of the door.

In addition, a shot peening process may be performed on the double-steel pipe processed into a curved shape.

In addition, an outer reinforcing rib is formed on the outer peripheral surface of the inner tube in a longitudinal direction, and an inner reinforcing rib in the longitudinal direction corresponding to the outer reinforcing rib is formed inside the outer tube, and the inner tube is inside the outer tube. can be inserted in a straight line.

In addition, an outer reinforcing rib of a helical shape is formed on the outer circumferential surface of the inner tube, and an inner reinforcing rib of a helical shape corresponding to the outer reinforcing rib is formed inside the outer tube, and the inner tube is inside the outer tube. can be inserted rotationally.

In addition, by preparing at least one or more additional steel pipes having different diameters from the inner pipe and the outer pipe, inserting the prepared additional steel pipe inside the inner pipe, or inserting the double steel pipe inside the additional steel pipe, a multi-steel pipe pipe The method further comprising the step of preparing to 1350° C., and the forming includes drawing the heat-treated multi-steel pipe pipe straight into a specific shape, and the cutting step includes cutting the pultruded multi-steel pipe pipe to a predetermined length. can be configured.

On the other hand, the present invention provides a door impact beam manufactured by the door impact beam manufacturing method using the double steel pipe of the above configuration.

According to the present invention, the double pipe is composed of a carbon steel pipe and an aluminum steel pipe to improve strength, reduce manufacturing cost, and realize weight reduction.

In addition, the first quenching heat treatment or the second quenching heat treatment process of the carbon steel constituting the inner tube or the outer tube is inlined and performed collectively to shorten the manufacturing time while maintaining uniform tensile strength, It is possible to improve the mutual bonding strength of the tube and the outer tube, and has the effect of minimizing structural deformation during compression, heat treatment, and drawing processes.

1 schematically shows a flowchart of a door impact beam manufacturing method using a double steel pipe according to an embodiment of the present invention.
FIG. 2 shows a door impact beam manufacturing method using the double steel pipe of the first example of FIG. 1 .
3 is a view showing a door impact beam manufacturing method using the double steel pipe of the second example of FIG.
4 is a block diagram illustrating steps from raw material processing to packaging of the method for manufacturing the door impact beam using the double steel pipe of FIG. 1 .
5 is a view showing an application example of the door impact multi-pipe beam manufactured by the door impact beam manufacturing method using the double steel pipe of FIG. 1, respectively.
FIG. 6 illustrates the reinforcing rib structure of the inner tube and the outer tube applied to the method for manufacturing the door impact beam using the double steel tube of FIG. 1 .

Hereinafter, embodiments of the present invention having the above-described characteristics with reference to the accompanying drawings will be described in more detail.

In the door impact beam manufacturing method using a double steel pipe according to an embodiment of the present invention, the door impact beam is manufactured as a double steel pipe. Specifically, as shown in FIG. 1, a first metal material is drawn through a drawing process to a first diameter Preparing the inner tube 110 of (S110), preparing the outer tube 120 of the second diameter through the drawing process of the second metal material (S120), the inner tube inside the outer tube 120 ( 110) to prepare a double steel pipe pipe by inserting (S130), inserting the double steel pipe pipe into the ram and extruding it (S140), and heat-treating the double steel pipe pipe extruded from the ram at 150°C to 1350°C (S150) ), drawing the heat-treated double steel pipe pipe straight into a specific shape (S160), and cutting the pultruded double steel pipe pipe to a predetermined length (S170), including the binding force and tension of the double steel pipe An object is to manufacture a door impact multi-tube beam with good strength.

Hereinafter, with reference to FIGS. 2 to 6, the door impact beam manufacturing method using the double steel pipe of the above-described configuration will be described in detail as follows.

Prior to that, as illustrated in FIG. 4 , the raw material forming the inner tube 110 and the outer tube 120 is cut to a predetermined length, and the inner tube 110 corresponding to the carbon steel tube ) or to perform subsequent high-frequency quenching (heat quenching) for the outer tube (120).

A first example of a door impact beam manufacturing method in which the inner tube 110 is made of carbon steel and the outer tube 120 is made of aluminum steel among the double steel tubes will be described in detail with reference to FIG. 2 as follows.

First, in the inner tube preparation step (S110), when the inner tube 110 is a carbon steel tube, the tubular carbon steel tube is heat-treated by high-frequency induction heating at 800° C. to 1100° C. for 1 second to 5 seconds (S111a) , after performing the first high-frequency quenching heat treatment (S111b) of quenching to 250 ° C or less within 5 sec (S111), drawing through the drawing process (S114) to prepare the inner tube 110 of the first diameter It consists of detailed steps.

Here, after performing the first high-frequency quenching heat treatment (S111), it branches, heat-treats by induction heating at 800°C to 1100°C for a certain period of time (S112a), and rapidly cools to 250°C or less within a certain period of time ( S112b) After performing the second induction quenching heat treatment (S112), after performing tempering at 200 ° C. to 700 ° C. for 30 minutes to 3 hours (S113), through the drawing process (S114) by drawing An inner tube 110 of a first diameter may be prepared.

That is, the same quenching heat treatment process of heat treatment and quench treatment using heat generation of current loss due to electromagnetic induction of a frequency exceeding 10 kHz is continuously performed twice.

For example, without an intermediate treatment process, through an in-line facility, immediately after the first quenching heat treatment, the second quenching heat treatment can be continuously batch-processed to shorten the manufacturing time and maintain uniform physical properties.

Accordingly, through the first quenching heat treatment (S111) or the second quenching heat treatment (S112), without a mold, high-strength heat treatment process of quenching at high frequency is performed to realize the tensile strength of the carbon steel pipe to 1200 MPa to 2000 MPa can

Here, when the tensile strength of the carbon steel pipe is 1200 MPa to 1500 MPa, the primary quenching heat treatment (S111) and tempering (S113) are performed, and when implemented with the tensile strength of the carbon steel pipe at 1500 MPa to 2000 MPa, the first Quenching heat treatment (S111), secondary quenching heat treatment (S112), and tempering (S113) can be performed, and according to consumer demand, if it is desired to realize the tensile strength of carbon steel pipe to 1200 MPa or less, 1 The primary quenching heat treatment and the secondary quenching heat treatment and tempering may be omitted.

That is, through the first quenching heat treatment (S111) or the second quenching heat treatment (S112), without a mold, high-strength heat treatment process of quenching at high frequency is performed to increase the tensile strength of carbon steel pipe or aluminum steel from 1200 MPa to 2000 MPa In the event of an external impact, the shock transmitted to the occupant and the occupant are maintained by maintaining the strength to prevent structural deformation of the door through the inner tube 110 while absorbing and mitigating the shock primarily through the outer tube 120 during an external impact. Injuries that can be sustained can be minimized.

Subsequently, in the external pipe preparation step ( S120 ), an external pipe 120 , which is an aluminum steel pipe of a second diameter, is prepared through a drawing process of aluminum steel, which is a second metal material.

On the other hand, the inner tube 110 and the outer tube 120, in addition to the carbon steel tube or aluminum steel, stainless steel, aluminum alloy, copper, copper alloy, nickel, nickel alloy, cobalt-based alloy steel, brass or high manganese steel any one or It may be manufactured by combining at least two or more.

Alternatively, a second example of a door impact beam manufacturing method in which the inner tube 110 is made of aluminum steel and the outer tube 120 is made of carbon steel among the double steel tubes will be described in detail with reference to FIG. 3 as follows.

First, in the inner tube preparation step ( S110 ), the inner tube 110 , which is an aluminum steel tube of a first diameter, is prepared through a drawing process of aluminum steel, which is a first metal material.

Subsequently, in the external pipe preparation step (S120), when the external pipe 120 is a carbon steel pipe, the tubular carbon steel pipe is heat-treated by high-frequency induction heating at 800° C. to 1100° C. for 1 second to 5 seconds (S121a) ), after performing the first high-frequency quenching heat treatment (S121b), which is quenched to 250° C. or lower within 5 sec (S121), and then drawn through the drawing process (S124) to have an outer tube with a second diameter larger than the first diameter It consists of detailed steps to prepare (120).

Here, after performing the first high-frequency quenching heat treatment (S121), it branches, heat-treats by high-frequency induction heating at 800°C to 1100°C for a certain period of time (S122a), and rapidly cools to 250°C or less within a certain period of time ( S122b) After performing the second high frequency quenching heat treatment (S122), after performing tempering at 200 ° C. to 700 ° C. for 30 minutes to 3 hours (S 123), through the drawing process (S 124) by drawing the first diameter An outer tube 120 having a larger second diameter may be prepared.

That is, the same quenching heat treatment process of heat treatment and quench treatment using heat generation of current loss due to electromagnetic induction of a frequency exceeding 10 kHz is continuously performed twice.

For example, without an intermediate treatment process, through an in-line facility, immediately after the first quenching heat treatment, the second quenching heat treatment can be continuously batch-processed to shorten the manufacturing time and maintain uniform physical properties.

Accordingly, through the first quenching heat treatment (S121) or the second quenching heat treatment (S122), without a mold, a high-strength heat treatment process of quenching at high frequency is performed to increase the tensile strength of the carbon steel pipe, which is a second metal material. It can be implemented at 1200 MPa to 2000 MPa.

Here, when the tensile strength of the carbon steel pipe is 1200 MPa to 1500 MPa, the first quenching heat treatment (S121) and tempering (S123) are performed, and when the tensile strength of the carbon steel pipe is 1500 MPa to 2000 MPa, the first Quenching heat treatment (S121), secondary quenching heat treatment (S122), and tempering (S123) can be performed, and according to consumer demand, if the tensile strength of the carbon steel pipe is to be implemented to 1200 MPa or less, 1 The primary quenching heat treatment and the secondary quenching heat treatment and tempering may be omitted.

That is, through the first quenching heat treatment (S121) or the second quenching heat treatment (S122), without a mold, high-strength heat treatment process of quenching at high frequency is performed to increase the tensile strength of carbon steel pipe or aluminum steel from 1200 MPa to 2000 MPa In the event of an external impact, the shock transmitted to the occupant and the occupant are maintained by maintaining the strength to prevent structural deformation of the door through the inner tube 110 while absorbing and mitigating the shock primarily through the outer tube 120 during an external impact. Injuries that can be sustained can be minimized.

Subsequently, in the case of the inner pipe 110 being a carbon steel pipe or the outer pipe 120 being a carbon steel pipe, in the double steel pipe preparation step S130 , the inner pipe 110 inside the outer pipe 120 is mechanically installed. Prepare a double steel pipe pipe by inserting it.

Meanwhile, as shown in FIG. 6 , when preparing a double steel pipe pipe, an outer reinforcing rib 111 is formed on the outer circumferential surface of the inner tube 110 in the longitudinal direction, and an outer reinforcing rib is formed on the inner side of the outer tube 120 . By forming the inner reinforcing rib 121 in the longitudinal direction corresponding to (111), and inserting the inner tube 110 in a straight direction inside the outer tube 120, it is possible to further increase the mutual bonding strength.

Alternatively, although not shown separately, an outer reinforcing rib of a helical shape is formed on the outer circumferential surface of the inner tube 110 , and an inner reinforcing rib of a helical shape corresponding to the outer reinforcing rib is formed inside the outer tube 120 . By forming a rotatably inserting the inner tube 110 inside the outer tube 120, the mutual bonding strength may be further increased.

Subsequently, in the ram extrusion step (S140), the double steel pipe pipe is put into a ram and extruded at a constant speed by a ram extrusion method using a stem or hydrostatic pressure.

Subsequently, in the double steel pipe heat treatment step (S150), the double steel pipe pipe extruded from the ram is heat treated at 150° C. to 1350° C. to form an integrated structure by thermally fusion of the inner tube 110 and the outer tube 120 In this way, structural deformation is minimized by increasing bonding strength and external shock is uniformly absorbed, and the subsequent pultrusion process is performed smoothly.

Subsequently, in the pultrusion forming step (S160), the heat-treated double steel pipe pipe is drawn into a straight shape and formed into a specific shape to improve the bonding strength of the double steel pipe.

On the other hand, during pultrusion molding, in accordance with the needs of consumers, the double-steel pipe can be formed by drawing it into a circular, oval, or polygonal cross-sectional shape.

In addition, the ram that has performed the previous ram extrusion step (S140), the heat treatment unit that performs the double steel pipe heat treatment step (S150), and the pultrusion unit that performs the pultrusion step (S160) are closely adjacent to each other and extruded Heat treatment and drawing process can be performed at the same time, and the extrusion force by the ram and the drawing force by the drawing unit are the same or are provided so that there is a slight difference within the error range, so that surface cracks and mechanical defects are minimized. can be molded.

In addition, the inner tube 110 and the outer tube 120 are repeatedly subjected to quenching heat treatment twice and then inserted to form a double steel tube to minimize structural deformation during compression, heat treatment, and drawing processes.

Subsequently, in the cutting step (S170), the pultrusion-formed double steel pipe pipe is cut to a predetermined length suitable for the impact multi-pipe beam mounted inside the door.

On the other hand, in the bending processing step (S180), the previously cut double steel pipe pipe can be processed into a curved or arcuate shape by additionally die quenching, forming, or bending methods according to the shape of various types of doors. can

Here, by performing a shot peening process on a double-steel pipe processed into a curved shape, the surface is forged to improve abrasion resistance, fatigue strength, and mechanical properties.

In addition, as illustrated in FIG. 4, after shot peening, calibration and chamfering of the completed door impact multi-tube beam is performed, and quality inspection is performed to inspect defects on the inner and outer surfaces, and packaging ( packing) is finally commercialized.

On the other hand, the door impact multi-pipe beam of the double steel pipe structure of the inner tube and the outer tube has been described above as an example, but the present invention is not limited thereto, and the same can be applied to a door impact beam manufacturing method using a double steel tube having a structure of three or more tubes.

For example, as shown in FIG. 1 , at least one additional steel pipe (not shown) having a diameter different from that of the inner tube 110 and the outer tube 120 is prepared, and the prepared additional steel tube is placed inside the inner tube 110 . The step of inserting or inserting a double steel pipe inside an additional steel pipe to prepare a multi-steel pipe pipe (S135) further includes the step of inserting and extruding the multi-steel pipe into the ram (S140), inserting the prepared multi-steel pipe into the ram and extruding and heat-treating (S150) heat-treating the multi-steel pipe extruded from the ram at 150° C. to 1350° C. And, the cutting step (S170) may be configured to cut the pultruded multi-steel pipe pipe to a predetermined length.

In addition, the aluminum steel pipe is composed of a thickness of about 1 mm, and the carbon steel pipe is composed of a thickness of about 2 mm, so that manufacturing cost can be reduced and weight reduction can be realized.

On the other hand, the present invention can provide a door impact beam manufactured by the door impact beam manufacturing method using the double steel pipe of the above configuration.

Therefore, by the configuration of the door impact beam manufacturing method using the double steel pipe as described above, the primary quenching heat treatment or the secondary quenching heat treatment process of the carbon steel constituting the inner tube or the outer tube is inlined and integrated It is possible to shorten the manufacturing time while maintaining uniform tensile strength, to improve the mutual bonding strength between the inner tube and the outer tube, and to minimize structural deformation during compression, heat treatment and drawing processes.

Configurations shown in the embodiments and drawings described in this specification are only the most preferred embodiment of the present invention, and do not represent all of the technical spirit of the present invention, so various equivalents that can be substituted for them at the time of the present application It should be understood that there may be water and variations.

110: inner tube 120: outer tube
S110: Inner tube preparation stage
S120: External tube preparation stage
S130: double steel pipe preparation stage
S135: Multi-steel pipe preparation stage
S140: Ram Extrusion Step
S150 : Double steel pipe pipe heat treatment step
S160: cutting step
S170: bending processing step

Claims (13)

preparing an inner tube of a first diameter through a drawing process of a first metal material;
preparing an outer tube of a second diameter through a drawing process of a second metal material;
preparing a double steel pipe by inserting the inner tube inside the outer tube;
inserting the double steel pipe into a ram and extruding it;
heat-treating the double steel pipe extruded from the ram at 150° C. to 1350° C.;
forming a specific shape by drawing the heat-treated double steel pipe pipe into a straight shape; and
Cutting the pultrusion-formed double steel pipe pipe to a predetermined length; manufacturing a door impact multi-pipe beam with good bonding strength and tensile strength of the double steel pipe, including,
The first metal material is carbon steel, the second metal material is made of aluminum steel,
The step of preparing the inner tube is
The first metal material in the tubular shape is heat-treated by high-frequency induction heating at 800° C. to 1100° C. for 1 second to 5 seconds, and primary quenching heat treatment of rapid cooling to 250° C. or less within 5 seconds, 200° C. After performing tempering for 30 minutes to 3 hours at 700 ° C., it is configured to prepare an inner tube of a first diameter through a drawing process,
The step of preparing the inner tube is
After performing the first quenching heat treatment, the second quenching heat treatment is additionally performed by high-frequency induction heating at 800° C. to 1100° C. for 1 second to 5 seconds, and quenching to 250° C. or less within 5 sec. After performing further, after performing tempering at 200 ° C. to 700 ° C. for 30 minutes to 3 hours, it is configured to prepare an inner tube of the first diameter through a drawing process,
The double steel pipe pipe is drawn and molded into a circular, oval or polygonal cross-sectional shape,
Further comprising the step of processing the cut double steel pipe pipe into a curved shape by die quenching, forming or bending method according to the shape of the door,
Through the in-line facility, after the first quenching heat treatment, immediately batch processing the second quenching heat treatment continuously,
The double steel pipe pipe is drawn and molded into a circular, oval or polygonal cross-sectional shape,
The aluminum steel pipe made of the aluminum steel is composed of a thickness of 1 mm, the carbon steel pipe made of the carbon steel is composed of a thickness of 2 mm, and the tensile strength of the carbon steel pipe is 1200 MPa to 2000 MPa,
Further comprising the step of processing the cut double steel pipe pipe into a curved shape by die quenching, forming or bending method according to the shape of the door,
A shot peening process is performed on the double-steel pipe processed into a curved shape,
After the shot peening, performing a calibration and chamfering process of the completed door impact multi-tube beam, performing a quality inspection to inspect the defects of the inner and outer surfaces, packaging and finally commercializing the product, characterized in that it further comprises ,
A method of manufacturing a door impact beam using a double steel pipe.
delete delete According to claim 1,
The step of preparing the outer tube is
The tubular second metal material is heat-treated by high-frequency induction heating at 800° C. to 1100° C. for 1 second to 5 seconds, and primary quenching heat treatment of rapid cooling to 250° C. or less within 5 seconds, 200° C. A method of manufacturing a door impact beam using a double steel pipe, characterized in that it is configured to prepare an external pipe of a second diameter through a drawing process after performing tempering at to 700° C. for 30 minutes to 3 hours.
5. The method of claim 4,
The step of preparing the outer tube is
After performing the first quenching heat treatment, the second quenching heat treatment is additionally performed by high-frequency induction heating at 800° C. to 1100° C. for 1 second to 5 seconds, and quenching to 250° C. or less within 5 sec. After further performing, after performing tempering at 200° C. to 700° C. for 30 minutes to 3 hours, the door impact beam using a double steel pipe, characterized in that it is configured to prepare an external pipe of a second diameter through a drawing process manufacturing method.
6. The method of claim 5,
Through an in-line facility, immediately after the first quenching heat treatment, the second quenching heat treatment is continuously batch-processed, a door impact beam manufacturing method using a double steel pipe.
delete delete delete According to claim 1,
Forming an outer reinforcing rib in the longitudinal direction on the outer circumferential surface of the inner tube, and forming an inner reinforcing rib in the longitudinal direction corresponding to the outer reinforcing rib on the inside of the outer tube, the inner tube is straight line inside the outer tube A method of manufacturing a door impact beam using a double steel pipe, characterized in that it is inserted in the direction.
According to claim 1,
An outer reinforcing rib of a helical shape is formed on the outer circumferential surface of the inner tube, and an inner reinforcing rib of a helical shape corresponding to the outer reinforcing rib is formed inside the outer tube, and the inner tube is rotated inside the outer tube. A method of manufacturing a door impact beam using a double steel pipe, characterized in that inserting it.
According to claim 1,
Prepare at least one additional steel pipe having a diameter different from that of the inner pipe and the outer pipe, inserting a prepared additional steel pipe inside the inner pipe, or inserting the double steel pipe inside the additional steel pipe to prepare a multi-steel pipe pipe further comprising the step of
In the step of extruding by putting the ram into the ram, the prepared multi-steel pipe is put into the ram and extruded,
In the heat treatment, the multi-steel pipe extruded from the ram is heat-treated at 150° C. to 1350° C.,
In the forming, the heat-treated multi-steel pipe is drawn into a straight shape and formed into a specific shape,
In the cutting step, the door impact beam manufacturing method using a double steel pipe, characterized in that configured to cut the pultruded multi-steel pipe pipe to a predetermined length.
A door impact beam manufactured by the door impact beam manufacturing method using the double steel pipe according to claim 1 .

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