1. Laser welding

Laser welding: Laser radiation heats the surface to be processed, and surface heat is directed internally through heat transfer. By controlling laser parameters such as pulse width,

energy, peak power, and repetition frequency, the workpiece is melted to form a specific molten pool.

▲Spot welding and fixing of welded components

▲ Conduct continuous laser welding

Laser welding can be achieved using continuous or pulsed laser beams, and the principles of laser welding can be divided into heat conduction welding and laser deep penetration

welding. When the power density is less than 10-10 W/cm, it is heat conduction welding, where the melting depth is shallow and the welding speed is slow; When the power density

is greater than 10-10 W/cm, the metal surface is heated and concave into "holes", forming deep penetration welding, which has the characteristics of fast welding speed and large

aspect ratio.

Laser welding technology is widely applied in high-precision manufacturing fields such as automobiles, ships, airplanes, and high-speed railways, bringing significant improvements

to people's quality of life and leading the home appliance industry into the era of precision engineering.

Especially after the 42 meter seamless welding technology created by Volkswagen greatly improved the overall integrity and stability of the vehicle body, Haier Group, a leading

household appliance company, grandly launched the first washing machine produced using laser seamless welding technology. Advanced laser technology can bring huge changes

to people's lives.

2. Laser composite welding

Laser composite welding is a combination of laser beam welding and MIG welding technology, achieving the best welding effect and fast bridging ability with the weld seam. It is currently

the most advanced welding method.

The advantages of laser hybrid welding are: high speed, small thermal deformation, small heat affected area, and ensuring the metal structure and mechanical properties of the weld.

Laser composite welding is not only suitable for welding automotive thin plate structural components, but also for many other applications. For example, applying this technology to the

production of concrete pumps and mobile crane booms requires the processing of high-strength steel. Traditional technologies often increase costs due to the need for other auxiliary

processes such as preheating. Furthermore, this technology can also be applied to the manufacturing of rail vehicles and conventional steel structures (such as bridges, fuel tanks, etc.).

3. Friction stir welding

Friction stir welding uses friction heat and plastic deformation heat as welding heat source. The welding process of friction stir welding is that a cylinder or other shape (such as a threaded

cylinder) of stirring needle is inserted into the seam of the workpiece, and the high-speed rotation of the welding head makes it friction with the welding workpiece material, so as to increase

the temperature of the material at the connection part and soften it.

During the welding process of friction stir welding, the workpiece shall be rigidly fixed on the back cushion, the welding head shall rotate at high speed, and the workpiece shall move relatively

along the seam of the workpiece.

The protruding section of the welding head extends into the interior of the material for friction and stirring. The shoulder of the welding head rubs against the surface of the workpiece to generate

heat, and is used to prevent the overflow of plastic state materials, while also playing a role in removing surface oxide film.

Leave a keyhole at the end of the friction stir weld. Usually, this keyhole can be cut off or sealed with other welding methods.

Friction stir welding can realize welding between dissimilar materials, such as metal, ceramics, plastics, etc. Friction stir welding has high welding quality, is not easy to produce defects, and is easy

to realize mechanization, automation, stable quality, low cost and high efficiency.

4. Electron beam welding

Electron beam welding is a method of welding that utilizes the thermal energy generated by accelerated and focused electron beams bombarding welded parts placed in vacuum or non vacuum.

Electron beam welding is widely used in many industries such as aerospace, atomic energy, national defense and military industry, automobiles, and electrical and electrical instruments due to

its advantages of no welding rods, less oxidation, good process repeatability, and low thermal deformation.

▲ Principles of electron beam welding

Electrons escape from the emitter (cathode) of the electron gun and are accelerated to 0.3 to 0.7 times the speed of light under the action of an accelerating voltage, possessing a certain amount

of kinetic energy. Through the action of electrostatic lens and electromagnetic lens in the electron gun, the electron beam with high success rate and density can be converged. This type of electron

beam impacts the surface of the workpiece, converting the kinetic energy of electrons into thermal energy, causing the metal to quickly melt and evaporate. Under the action of high-pressure metal

vapor, a small hole, also known as a "keyhole", is quickly "drilled" on the surface of the workpiece. As the electron beam moves relative to the workpiece, the liquid metal flows around the small hole

to the rear of the molten pool and cools and solidifies to form a weld seam.

The main characteristics of electron beam welding

The electron beam has strong penetration ability, extremely high power density, and a large weld depth to width ratio, which can reach 50:1. It can achieve one-time forming of thick materials, with a

maximum welding thickness of 300mm. Good welding reachability, fast welding speed, generally above 1m/min, small Heat-affected zone, small welding deformation, and high welding structure

precision. The energy of the electron beam can be adjusted, and the thickness of the welded metal can range from thin to 0.05mm to thick to 300mm. Without grooves, it can be formed in one

welding process, which cannot be achieved by other welding methods. The range of materials that can be used for electron beam welding is large, especially suitable for welding active metals,

refractory metals, and workpieces with high quality requirements.

5. Ultrasonic metal welding

Ultrasonic metal welding is a special method of connecting the same or different metals using the mechanical vibration energy of ultrasonic frequency. When ultrasonic welding is carried out for metal,

neither current is transmitted to the workpiece nor high temperature heat source is applied to the workpiece, but the vibration energy of the frame is transformed into friction work, deformation energy

and limited temperature rise under static pressure. Metallurgical bonding between joints is a solid-state welding process achieved without melting the base material.

It effectively overcomes the phenomena of splashing and oxidation generated during resistance welding. Ultrasonic metal welding machines can perform single point welding, multi-point welding, and

short strip welding on fine wires or thin materials of non-ferrous metals such as copper, silver, aluminum, and nickel. It can be widely used for welding controllable silicon leads, fuse links, electrical leads,

lithium battery pole pieces, and pole ears.

Ultrasonic metal welding utilizes high-frequency vibration waves to transmit to the metal surface to be welded, causing friction between two metal surfaces under pressure to form fusion between molecular layers.

The advantages of ultrasonic metal welding are fast, energy-saving, high fusion strength, good conductivity, no spark, and close to cold processing; The disadvantages are that the welded metal parts cannot be

too thick (usually less than or equal to 5mm), the welding points cannot be too large, and pressure needs to be applied.

6. Flash butt welding

The principle of flash butt welding is to use a butt welding machine to make the metal at both ends come into contact. Through a low voltage and strong current, the metal is heated to a certain temperature and

softened, and then subjected to axial pressure forging to form a butt welding joint.

Before the two welding parts come into contact, they are clamped by two clamp electrodes and connected to the power supply. The movable fixture is moved, and the end faces of the two welding parts lightly

contact and are electrified for heating. The contact point explodes due to heating, forming a liquid metal, and sparks are sprayed to form a flash. The movable fixture is continuously moved, and the flash occurs

continuously. The two ends of the welding part are heated. After reaching a certain temperature, the end faces of the two workpieces are squeezed, the welding power is cut off, and the welding is firmly welded

together. Using resistance to heat the joint of the weldment to produce a flash at the contact point, melting the metal on the end face of the weldment, and quickly applying top force to complete the welding.

Steel bar flash butt welding is a pressure welding method that involves installing two steel bars into a butt joint, utilizing the resistance heat generated by the welding current passing through the contact points

of the two steel bars to melt the metal at the contact points, generate strong splashes, and form a flash accompanied by a pungent odor, release trace molecules, and quickly apply top forging force to complete

the welding.