CN104439684A - Self-piercing riveting method assisted by ultrasonic - Google Patents

Abstract

An ultrasonic-assisted self-piercing riveting method, which is realized through a self-piercing riveting system. The specific steps are as follows: the upper plate and the lower plate are paired and sufficiently close to or in contact with each other, and placed above the die; the ultrasonic generating device and the rivet fixture The included angle α is 0°～180°, the output ultrasonic power is 1～90kW, and the ultrasonic amplitude is 3～60μm; the semi-tubular rivet moves downward under the assistance of ultrasonic waves and inserts the upper and lower plates to be welded until it reaches the die After being filled, the ultrasonic vibration continues for 0-2 seconds. The invention solves the problems of cracking, difficult deformation and non-metallurgical bonding existing in the existing self-piercing riveting of difficult-to-deform materials, and also solves the problem of a large number of brittle compounds generated during resistance spot welding of dissimilar materials. The pressure resistance of the rivet is improved, the mechanical-metallurgical double connection is realized, and the mechanical properties of the joint are improved.

Description

An ultrasonic-assisted self-piercing riveting method

technical field

The invention relates to a mechanical solid-phase composite connection method, in particular to an ultrasonic-assisted self-piercing riveting method, which belongs to the field of welding technology.

Background technique

The main joining methods currently used in vehicle body assembly are resistance spot welding and self-piercing riveting.

Resistance spot welding has irreplaceable advantages in welding single-material traditional steel bodies, and has been successfully used in industry on a large scale for decades. However, with the continuous increase in the demand for weight reduction of vehicles, the body materials are rapidly developing in the direction of light weight. There are huge problems in the resistance spot welding when welding the body composed of high-strength steel and light alloy dissimilar materials. The welding temperature is extremely high during spot welding, and a large number of brittle intermetallic compounds are produced at the welding interface, which greatly reduces the mechanical properties of the joint.

Self-piercing riveting technology is a mechanical joining method that has been widely used in the industry since the 1990s. Self-piercing riveting has the advantages of short process cycle, no piercing of the underlying plate, connection of dissimilar materials, and no smoke, dust and sparks during riveting. It is especially suitable for materials with good plasticity such as aluminum alloys. However, when the self-piercing riveting method is used to weld magnesium alloys, high-strength steels and other materials with poor plasticity and high strength, there are serious problems such as cracking of the lower magnesium alloys and difficulty in deformation of high-strength steels; : Aluminum-steel dissimilar material joint, due to the extremely low joining temperature (less than 150 degrees Celsius), only a single mechanical connection is formed between the materials to be connected, without any metallurgical connection, so that the mechanical properties of the joint are at a low level.

Contents of the invention

In order to solve the problems of cracking, difficult deformation and no metallurgical bonding existing in self-piercing riveting of hard-to-deform materials, and also to solve the problems of high temperature and a large number of brittle compounds during resistance spot welding, the invention provides an ultrasonic-assisted self-piercing riveting The punching riveting welding method is based on the self-piercing riveting technology, and the power ultrasonic is applied to the self-piercing rivet, so as to reduce the pressure resistance of the rivet, soften the hard-to-deform material, and form the effect of mechanical-metallurgical double connection.

The present invention is achieved through the following technical solutions:

An ultrasonic-assisted self-piercing riveting method, which is realized by a self-piercing riveting system, the self-piercing riveting system includes a semi-hollow rivet, a rivet fixture, a die and an ultrasonic generating device, and the specific steps of the self-piercing riveting method are as follows:

Step 1. Combine the welded upper plate and the lower plate so that the two are sufficiently close or in contact;

Step 2, placing the paired upper and lower plates above the die;

Step 3, setting the angle α between the ultrasonic generating device and the rivet fixture;

Step 4, turn on the power supply of the ultrasonic generating device, so that the ultrasonic generating device starts to output ultrasonic waves;

Step 5. The semi-hollow rivet moves downward under the drive of the rivet fixture, presses into and penetrates the upper plate, and then pierces into the lower plate to deform it until the die is filled. The rivet stops moving downward;

Step 6, the semi-tubular rivet stays in the die and maintains ultrasonic vibration for 0-2 seconds;

Step 7. The semi-tubular rivet breaks away from the rivet fixture and remains in the material to be welded. The rivet fixture moves upward to a designated position, and the welding process is completed.

Further, in step three, the angle α between the ultrasonic generating device and the rivet fixture is variable in the range of 0°≤α≤180°.

Further, in step four, the power of the ultrasonic waves is 1-90 kW.

Further, in step 4, the amplitude of the ultrasonic waves is 3-60 μm.

Further, the ultrasonic generating device is connected to the rivet fixture by welding or other mechanical fixing methods.

The principle of the present invention is that the ultrasonic vibration is transmitted from the ultrasonic generating device to the rivet fixture, and then transmitted to the semi-hollow rivet; when the semi-hollow rivet is in contact with the upper plate, high-frequency friction occurs between the two under the ultrasonic drive, and at the same time, Driven by ultrasonic vibration, the upper plate also undergoes high-frequency friction with the lower plate to be welded; as the semi-hollow rivet is further pressed down to contact the lower plate, high-frequency friction occurs between the two. At the same time, under the action of ultrasound, the lower plate and the High-frequency friction also occurs between the dies; on the one hand, these four high-frequency frictions soften the plates to be welded, making them easy to deform, avoiding cracks, and reducing the resistance of the semi-hollow rivets to press down, on the other hand, between the upper and lower plates. The high-frequency friction creates a metallurgical bond between them, thereby improving the performance of the joint.

Compared with prior art, the beneficial effect of the present invention is:

1. The high-frequency friction between the semi-hollow rivet and the upper plate softens the upper plate and reduces the pressure resistance;

2. The high-frequency friction between the semi-hollow rivet and the lower plate softens the lower plate, making it easy to deform, avoiding cracking, and reducing the pressure resistance;

3. The high-frequency friction between the upper plate and the lower plate makes the metallurgical combination of the two on the interface, realizes the mechanical-metallurgical double combination, and improves the mechanical properties of the joint;

4. The high-frequency friction between the lower plate and the die softens the lower plate, avoids cracking, reduces deformation resistance, and makes it easier to fill the die;

5. The reduction of the down pressure resistance can make the riveting and welding equipment lightweight and reduce the volume of the riveting and welding equipment.

Description of drawings

Fig. 1 is a structural schematic diagram of the present invention.

In the figure, the double-headed arrow represents the direction of ultrasonic vibration, and the downward arrow represents the direction of pressure in riveting welding.

Detailed ways

The embodiments of the present invention are described in detail below. Based on the premise of the technical solution of the present invention, the embodiments provide detailed implementation and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

Example 1

As shown in Figure 1, the self-piercing riveting system includes a semi-tubular rivet 2, a rivet fixture 1, a die 5 and an ultrasonic generator 6, which is connected to the rivet fixture 1 by welding or other mechanical fixation , and the two form an angle α. The ultrasonic-assisted self-piercing riveting method is realized by the self-piercing riveting system, and the specific steps of the self-piercing riveting method are as follows:

Step 1, pairing the upper plate to be welded 3 and the lower plate to be welded 4 so that the two are sufficiently close to or in contact with each other;

Step 2, placing the paired upper plate 3 and the lower plate 4 above the die 5;

Step 3, setting the angle α between the ultrasonic generating device 6 and the rivet fixture 1 to be 0°;

Step 4, turn on the power supply of the ultrasonic generating device 6, so that the ultrasonic generating device 6 starts to output ultrasonic waves, the power of the ultrasonic waves is 1kW, and the amplitude of the ultrasonic waves is 3 μm;

Step 5. The semi-hollow rivet 2 moves downward under the drive of the rivet fixture 1, presses into and penetrates the upper plate 3, and then pierces into the lower plate 4 to deform it until the die 5 is filled. full, the semi-tubular rivet 2 stops moving downward;

Step 6, the semi-tubular rivet 2 stays in the die 5 and maintains ultrasonic vibration for 0 seconds;

Step 7. The semi-tubular rivet 2 breaks away from the rivet fixture 1 and remains in the material to be welded. The rivet fixture 1 moves upward to a designated position, and the welding process is completed.

Example 2

In step three of this embodiment, the angle α between the ultrasonic generating device 6 and the rivet fixture 1 is set to 90°; the angle α can be selected according to actual welding needs, and the closer the angle α is to 90° °, the stronger the lateral vibration, the more favorable the friction between the upper and lower plates, and the formation of metallurgical bonding between the two; the closer the angle α is to 0°, the stronger the longitudinal vibration, which is more conducive to reducing the semi-hollow rivets Down pressure; in step 4, the power of the ultrasonic wave is 2kW, and the amplitude of the ultrasonic wave is 10 μm; in step 6, the time for maintaining the ultrasonic vibration is 1.5 seconds; other steps of this embodiment are the same as in embodiment 1.

Example 3

In Step 3 of this embodiment, the angle α between the ultrasonic generating device 6 and the rivet fixture 1 is set to 30°; in Step 4, the power of the ultrasonic wave is 3 kW, and the amplitude of the ultrasonic wave is 20 μm; In step 6, the time for maintaining ultrasonic vibration is 0.5 seconds; the power of the ultrasonic wave can be selected according to the strength and thickness of the material to be welded to enhance the strength of the joint; other steps in this embodiment are the same as in embodiment 1.

Example 4

In step three of the present embodiment, the angle α between the ultrasonic generating device 6 and the rivet fixture 1 is set to 60°; in step four, the power of the ultrasonic waves is 70 kW, and the amplitude of the ultrasonic waves is 35 μm ; In step 6, the time for maintaining ultrasonic vibration is 1 second; the amplitude of the ultrasonic wave can be selected according to the characteristics of the material to be welded to enhance the strength of the joint; other steps of this embodiment are the same as in Embodiment 1.

Example 5

In Step 3 of this embodiment, the angle α between the ultrasonic generating device 6 and the rivet fixture 1 is set to 45°; in Step 4, the power of the ultrasonic wave is 90 kW, and the amplitude of the ultrasonic wave is 60 μm; In step 6, the time for maintaining the ultrasonic vibration is 2 seconds; the time for maintaining the ultrasonic vibration can be selected according to the characteristics of the materials to be welded to enhance the strength of the joint. High; other steps of this embodiment are the same as in embodiment 1.

Claims (5)

1. A self-piercing riveting method assisted by ultrasonic waves, characterized in that: realize by a self-piercing riveting system, this self-piercing riveting system comprises a semi-tubular rivet, a rivet clamp, a die and an ultrasonic generating device, the self-piercing riveting method Specific steps are as follows: Step 1. Combine the welded upper plate and the lower plate so that the two are sufficiently close or in contact; Step 2, placing the paired upper and lower plates above the die; Step 3, setting the angle α between the ultrasonic generating device and the rivet fixture; Step 4, turn on the power supply of the ultrasonic generating device, so that the ultrasonic generating device starts to output ultrasonic waves; Step 5. The semi-hollow rivet moves downward under the drive of the rivet fixture, presses into and penetrates the upper plate, and then pierces into the lower plate to deform it until the die is filled. The rivet stops moving downward; Step 6, the semi-tubular rivet stays in the die and maintains ultrasonic vibration for 0-2 seconds; Step 7. The semi-tubular rivet breaks away from the rivet fixture and remains in the material to be welded. The rivet fixture moves upward to a designated position, and the welding process is completed. 2. The ultrasonic-assisted self-piercing riveting method according to claim 1, characterized in that: in step 3, the angle α between the ultrasonic generating device and the rivet fixture is in the range of 0°≤α≤180° variable in range. 3. The ultrasonic-assisted self-piercing riveting method according to claim 1 or 2, characterized in that in step 4, the power of the ultrasonic wave is 1-90 kW. 4. The ultrasonic-assisted self-piercing riveting method according to claim 1 or 2, characterized in that in step 4, the amplitude of the ultrasonic waves is 3-60 μm. 5. The ultrasonic-assisted self-piercing riveting method according to claim 1 or 2, characterized in that: the ultrasonic generating device and the rivet fixture are connected by welding or other mechanical fixing methods.