What is laser welding used for?

In modern manufacturing, laser welding has become a key technology in many industries due to its advantages such as high precision, high efficiency and non-contact processing. Compared with traditional welding methods, laser welding can achieve finer welds, lower material deformation and faster processing speed. So, what is laser welding used for? This article will explore the application areas, advantages and future development trends of laser welding.

What is laser welding?

Laser welding is an advanced welding technology that uses a high-energy laser beam as a heat source to partially melt the material and form a strong connection. Compared with traditional welding (such as arc welding and resistance welding), laser welding has a higher energy density and can achieve micron-level precision welding. It is suitable for materials such as metals, plastics and even ceramics.

How does laser welding work?

Basic process of laser welding:

1. Laser beam focusing: The laser beam is focused to a very small spot (usually 0.1~1mm) through an optical lens or reflector.
2. Material absorption of energy: High-energy laser causes the irradiated area to heat up rapidly to the melting point or vaporization temperature.
3. Molten pool formation: The metal melts to form a molten pool, which solidifies into a weld after cooling.
4. Welding completion: Welding of different depths and widths can be achieved by precisely controlling laser parameters (power, speed, pulse frequency).

Two main modes of laser welding

Welding mode	Features	Applicable scenarios
Heat conduction welding	Low-power laser, material surface melting, shallow weld	Thin plate welding (such as electronic components, precision instruments)
Deep melting welding (keyhole welding)	High-power laser, material vaporization to form a deep molten pool	Thick plate welding (such as automobiles, aerospace structures)

What are the main types of laser welding?

Depending on the laser, laser welding is mainly divided into:

1.Fiber laser welding (Fiber Laser)

High beam quality, suitable for highly reflective materials (such as aluminum and copper).

Widely used in the automotive and 3C electronics industries.

2.CO₂ laser welding (CO₂ Laser)

Longer wavelength, suitable for non-metallic and partial metal welding.

Commonly used for thick plate welding, but with low efficiency.

3.Nd:YAG laser welding (solid-state laser)

Pulse mode is suitable for precision welding, such as medical equipment and jewelry.

4.Ultrafast laser welding (femtosecond/picosecond laser)

Extremely short pulse, extremely small heat-affected zone, suitable for brittle materials (such as glass and semiconductors).

What are the advantages of laser welding?

Laser welding has many advantages over other welding methods such as MIG, TIG, and arc welding. Let’s look at some of the most important ones.

• High precision: The laser beam can be focused to the micron level, which is suitable for welding tiny parts (such as electronic chips).
• Low thermal deformation: The heat-affected zone is small, which reduces material deformation and improves the yield rate.
• High speed and high efficiency: The welding speed can reach several meters per minute, which is much higher than traditional welding.
• Non-contact processing: No mechanical stress, avoiding material damage.
• Automation compatibility: Easy to integrate into robots and CNC systems to achieve intelligent manufacturing.
• Environmental protection and energy saving: No welding slag, less smoke and dust, in line with the trend of green manufacturing.

How Does Laser Welding Achieve Aerospace-Grade Joint Integrity?

Laser welding is a key technology system to achieve the integrity of aircraft-grade joints

1.High-energy beam precision control system

IPG YLS-6000 fiber laser (6kW/m²<1.3) ensures:

• Beam focusing diameter 0.03mm (±0.005mm)
• Power stability±0.5%
• BPP value < 0.4 mm·mrad

2.Special welding process for aerospace materials

Titanium Alloy Welding Specifications:
a) Follow the AMS 2680D standard
b) Welding speed: 15m/min (0.3mm sheet)
c) Heat input control< 35J/mm
d) Keyhole depth fluctuation ± 0.02mm

3.Ultra-pure inert gas protection system

Dual-channel gas protection:

• Primary protection: 99.999% argon (25L/min)
• Secondary protection: helium-argon mixture (He75%, Ar25%)
• Oxygen content control< 5ppm (according to AMS 2681B)

4.Real-time quality monitoring system

Multi-sensor fusion monitoring:
a) Plasma spectroscopy (detection of elemental burnout)
b) Thermal imaging camera (ΔT±2°C)
c) High-speed camera (50000fps)

5.Microstructure manipulation techniques

• The grain size of the β phase is controlled < 15 μm
• Porosity<0.01% (ASTM E2375)
• Residual stress< 50MPa (XRD detection)

6.Mechanical properties are guaranteed

• Joint strength factor≥0.95 (base metal strength)
• Fatigue life (10^7 times) up to 90% of base metal
• Fracture toughness KIC ≥ 60MPa·m^1/2

This technology system has been successfully applied to:

1. Aerospace engine combustion chamber components (MTBF>10000h)
2. Spacecraft fuel tanks (leakage rate <1×10^-9 Pa·m³/s)
3. Satellite structural parts (dimensional stability <0.01mm/m)
4. Passed ISO 15614-11 certification, met AS9100D aviation quality management system requirements, and achieved “zero defect” aviation manufacturing standards for welded joints.

Why is Laser Welding Dominating EV Battery Manufacturing?

1. Core applications of laser welding in power battery manufacturing

1.1 Battery shell welding solution

• Material adaptability: Double pulse welding process optimized for 6061 aluminum alloy
• Process parameters: frequency 500Hz, pulse width 3ms precision control
• Structural advantages: Achieve high-quality welds with a depth-to-width ratio of 8:1 (traditional TIG welding is only 3:1)

1.2 Key component welding applications

• Battery cell tab welding
• Battery module connector welding
• Battery pack structural parts welding
• Cooling system pipeline welding

2. Six technical advantages of laser welding

2.1 Ultra-precision thermal control

• HAZ control: The heat affected zone is strictly controlled within 0.2mm
• Anti-permeation guarantee: Effectively prevent the risk of lithium electrolyte permeation
• Deformation: Welding deformation <0.1mm to ensure dimensional accuracy

2.2 Excellent welding quality

• Porosity: <0.5%, much lower than traditional welding
• Strength coefficient: more than 95% of the base metal
• Conductivity: Resistance increased by <5%

2.3 Efficient production

• Welding speed: up to 20m/min (3-5m/min for traditional methods)
• Degree of automation: 100% automated production compatible
• Cycle time: 0.5 sec < single solder joint

2.4 Wide adaptability of materials

• Aluminum alloy (1000/3000/6000 series)
• Copper and copper alloys
• Stainless steel
• Nickel alloys

2.5 High process stability Yield: >99.9%

• Repeatability: ±0.02mm
• Equipment MTBF: > 10,000 hours

2.6 Comprehensive cost advantage

• Reduced energy consumption: 40% less energy than traditional welding
• Material savings: 15% reduction in material consumption
• Labor cost: reduced by more than 50%.

3. Key indicators of power battery welding quality

3.1 Air tightness requirements

• Helium leak detection rate: <1×10^-9 Pa·m³/s
• Explosion pressure: ≥3 times working pressure

3.2 Electrical performance

• Contact resistance: <50μΩ
• Insulation resistance: >100MΩ

3.3 Mechanical strength

• Tensile strength: ≥200MP
• Fatigue life: >5000 vibration tests

4. Industry application cases

4.1 Process selection of leading battery manufacturers

• CATL: Full-process laser welding application
• BYD: Blade battery laser welding solution
• LG New Energy: Modular laser welding system
• Panasonic: 4680 battery laser welding process

4.2 Comparison of parameters of typical welding solutions

Parameters	Laser welding	Traditional TIG welding
Speed	15-20m/min	3-5m/min
Aspect ratio	8:1	3:1
HAZ	0.2mm	1-2mm
Deformation	<0.1mm	0.3-0.5mm
Energy consumption	3-5kW	8-12kW

Laser welding technology has become the standard process for manufacturing electric vehicle power batteries with its unparalleled precision, efficiency and reliability. As battery technology develops towards higher energy density and longer life, laser welding will continue to play a key role in promoting technological progress in the electric vehicle industry.

What Metals Challenge the Limits of Laser Welding?

Although laser welding technology has been widely used in industrial production, some special metal materials still pose severe challenges to it. Due to their unique physical and chemical properties, these materials often require the development of special laser welding processes. This section will take a deep look at the five most challenging metal materials and reveal how the latest process breakthroughs overcome these welding difficulties.

1. Highly reflective metals: copper and its alloys

1.1 Technical difficulties

• Laser reflectivity: infrared band >95%
• Thermal conductivity: up to 401W/(m·K)
• Typical applications: electric vehicle batteries, power electronics

1.2 Innovative solutions

Blue laser technology (450nm):

• Absorption rate increased to 65% (infrared only 5%)
• Welding depth consistency increased by 50%

Compound welding process:

• Laser-arc compound
• Laser-ultrasonic assistance

1.3 Industry breakthrough cases

Parameters	Traditional welding	Innovative process
Welding speed	3m/min	8m/min
Porosity	>5%	<0.5%
Conductivity	85%IACS	98%IACS

2. Dissimilar metal connection: copper-aluminum welding

2.1 Core challenges

• Metallurgical incompatibility: formation of brittle intermetallic compounds
• Thermal expansion difference: aluminum 23.1 vs copper 16.5 (10⁻⁶/℃)
• Application areas: automotive wiring harness, power connection

2.2 Key technological breakthroughs
Ultraviolet laser application (355nm):

• Absorption rate increased by 300%
• Interface compound thickness <2μm

Nano intermediate layer technology:

• Nickel-based nano coating
• Transition layer design

2.3 Performance indicators

• Tensile strength: >200N/mm² (SAE J2392)
• Resistivity: <3.5μΩ·cm
• Fatigue life: >5000 thermal cycles

3. High temperature alloy: nickel-based superalloy

3.1 Welding problems

• Crack sensitivity: HAZ liquefaction crack
• Element segregation: γ’ phase formation is hindered
• Typical materials: Inconel 718, Hastelloy

3.2 Advanced process solutions

Ultrafast laser welding:

• Pulse width <10ps
• Heat affected zone <30μm

Magnetic field assisted technology:

• Inhibit element segregation
• Grain refinement to 5-8μm

3.3 Aviation-grade performance

• Strength retention: >90% of parent material
• Endurance strength: 650℃/1000h
• Oxidation resistance: equivalent to forgings

4. High-strength aluminum alloy: 7xxx series

4.1 Main problems

• Hot crack tendency: large solidification range
• Strength loss: over-aging softening
• Application scenarios: aerospace structural parts

4.2 Solution path
Dual-beam laser technology:

• Main beam welding
• Auxiliary beam tempering
• Dynamic control process:
• Real-time power modulation
• Frequency 100-500Hz adjustable

4.3 Performance comparison

• Tensile strength: 580→550MPa (only 5% loss)
• Elongation: 10%→8%
• Fatigue limit: Δσ=200MPa @10⁷ times

5. Precious metals and special alloys

5.1 Special challenges

• Material cost: precious metals such as platinum and gold
• Extremely small size: medical electronic components
• Special properties: shape memory alloys

5.2 Precision welding solutions

Micro laser welding:

• Light spot <20μm
• Single pulse energy <1mJ

Protective atmosphere control:

• Oxygen content <1ppm
• Dew point <-70℃

5.3 Typical application data

• Heart stent welding: Φ0.1mm nickel-titanium wire
• Electronic contact welding: 50μm gold wire
• Precision jewelry repair: 0.01mm weld

With the continuous development of new laser technologies and process methods, metal materials that were traditionally considered “unweldable” are being conquered one by one. From highly reflective copper materials to dissimilar metal connections, from high-temperature alloys to precision precious metals, laser welding technology continues to break through physical limits and open up new possibilities for high-end manufacturing. In the next 5-10 years, as new technologies such as quantum lasers mature, the boundaries of laser welding capabilities will be further expanded.

 How Does Fiber Laser Technology Reduce Automotive Production Costs?

In the increasingly competitive automotive industry, production cost control is directly related to the market competitiveness of enterprises. Fiber laser technology, with its high efficiency, low energy consumption and excellent process adaptability, is reshaping the economic model of automobile manufacturing.

1. A dramatic improvement in production efficiency

1.1 Welding speed advantage

• Galvanized steel plate lap welding: speed up to 60mm/s

Comparative advantages:

• 5 times faster than traditional resistance welding
• 8-10 times faster than MIG welding
• Production line beat: single-vehicle welding time is shortened by 40%

1.2 Comparison of equipment utilization

Parameters	Fiber laser welding	Resistance spot welding	Improvement rate
Uptime	95%	85%	+10%
Mold change time	5min	30min	-83%
Fault interval	5000h	2000h	+150%

2. Substantial reduction in direct costs

2.1 Cost analysis of single-meter weld

• Fiber laser welding: $0.15/meter
• Resistance spot welding: $0.35/meter
• Cost savings: 57% per meter

2.2 Comprehensive cost structure

Energy consumption:

• Laser: 3.5kW·h/m
• Resistance welding: 8.2kW·h/m

Electrode loss:

• Laser: no electrode
• Resistance welding: $0.02/spot

Post-processing:

• Laser: basically not required
• Resistance welding: grinding $0.05/m

3. Effective control of quality costs

3.1 Comparison of quality indicators

Defect rate:

• Laser welding: <0.5%
• Resistance welding: 2-3%

Rework cost:

• Laser production line: $0.8/car
• Traditional production line: $3.5/car

3.2 Long-term quality benefits

Corrosion resistance:

• Laser continuous welding has better sealing
• Reduce 5-year rust repair cost by $15/car

Structural strength:

• Laser weld strength is 10-15% higher
• Reduce collision repair rate

4. Economic Returns from Production Line Transformation

4.1 Return on Investment Cycle
Typical Transformation Cases:

• Initial Investment: $2.5M
• Annual Savings: $1.7M
• ROI Cycle: 18 months (500 units/day)

4.2 Benefits from Capacity Improvement
Production Flexibility:

• Can handle 4-6 models at the same time
• Changeover time reduced by 70%

Site Savings:

• Equipment floor space reduced by 40%
• Plant cost reduced by $0.8M/year

5. Cost advantages of the entire life cycle

5.1 Comparison of maintenance costs
Laser system:

• Lens replacement: $0.01/m
• Fiber life: >50,000h

Resistance welding:

• Electrode maintenance: $0.03/m
• Transformer loss

5.2 Sustainable benefits

Energy consumption reduction:

• Annual electricity saving 1.2M kW·h
• Carbon reduction 850 tons/year

Material savings:

• Flange edge design optimization
• Single vehicle weight reduction 1.2kg

6. Industry application cases

6.1 Practices of mainstream car companies

• Tesla: Model Y integrated die casting + laser welding
• Toyota: TNGA architecture laser welding ratio increased to 65%
• Volkswagen: MEB platform laser welding cost reduced by 42%

Why is Laser Welding Critical for Microelectronics Packaging?

As semiconductor devices continue to miniaturize, traditional welding technology can no longer meet the chip packaging requirements of ultra-high precision, ultra-low thermal impact and extreme reliability. Laser welding technology has become an indispensable core process for modern microelectronics packaging due to its unique advantages.

1. Special requirements for microelectronic packaging

1.1 Core Challenges of Chip-Level Welding

• Size Limit: 20-50μm solder joint accuracy
• Thermal Sensitivity: Allowable temperature rise <5°C (to prevent silicon chip damage)
• Mechanical Requirements: 10g ultra-fine strength control
• Reliability: Passed the rigorous MIL-STD-883 test

1.2 Limitations of Traditional Technologies

Parameters	Thermo-ultrasonic welding	Laser welding
Minimum wire diameter	25μm	15μm
Heat-affected zone	100-200μm	20-50μm
Positioning accuracy	±10μm	±1μm
Production cycle	5-7 welds/second	20-30 welds/second

2. Key technological breakthroughs in laser welding

2.1 Ultra-precision energy control

• Microjoule pulse: 15mJ±0.3mJ energy stability
• Diameter control: gold ball solder joint 20μm±0.5μm
• Dynamic adjustment: ns-level real-time power feedback

2.2 Advanced optical system

• 5μm positioning accuracy: ultra-depth of field coaxial vision system
• Multi-wavelength monitoring: visible light + infrared synchronous imaging
• Intelligent focus: automatic Z-axis compensation ±2μm

2.3 Material engineering innovation

• Gold wire optimization: 4N high purity and no doping
• Interface control: Au-Al intermetallic compound <50nm
• Surface finishing: plasma cleaning Ra<0.1μm

3. Process reliability verification system

3.1 Mechanical properties test

• Tensile test: >10g/solder point (MIL-STD-883)
• Shear test: >15g/solder point
• Fatigue test: 1000 thermal cycles (-55~125℃)

3.2 Failure analysis standard

• SEM detection: interface diffusion layer analysis
• X-ray: internal void detection (<3%)
• FTIR: organic contamination analysis
• EBSD: grain orientation characterization

3.3 Mass production stability index

• CPK: >1.67 (6σ standard)
• UPH: ≥5000 solder points/hour
• MTBF: >10,000 hours

4. Typical application scenarios

4.1 High-end chip packaging

• CPU/GPU: gold wire diameter 15-20μm
• Memory chip: stacked package welding
• CIS sensor: ultra-thin glass substrate welding

4.2 Application of special devices

• MEMS sensor: vacuum sealing welding
• Power device: copper pillar bump welding
• Biochip: low temperature welding (<80℃)

5. Technical and economic analysis

5.1 Comparison of cost advantages

• Equipment investment: Laser system is 30% lower than thermal ultrasound
• Consumables cost: No chopping knife loss, saving $15k per year
• Yield improvement: from 99.5% to 99.95%

5.2 Production efficiency

• Changeover time: from 2 hours to 15 minutes
• Energy consumption reduction: from 800W to 150W
• Space saving: equipment volume reduced by 60%

Laser welding technology perfectly solves the problem of precision interconnection in microelectronic packaging through sub-micron precision, millisecond processing speed and excellent process controllability. From 20μm gold wire bonding to 3D chip stacking, this technology not only improves packaging reliability, but also promotes the development of semiconductor devices towards smaller size and higher performance. With the evolution of advanced packaging technology, laser welding will surely become an indispensable basic process in the post-Moore era.

How to Solve Porosity Issues in Aluminum Alloy Laser Welding?

During the laser welding of aluminum alloys, porosity is one of the main problems affecting the quality of joints. Studies have shown that the porosity of aluminum alloy laser welds under traditional processes is usually as high as 3-5%, which seriously restricts its application in high-end fields such as aerospace and new energy vehicles. LS will systematically introduce the most effective aluminum alloy laser welding porosity control technology to help you achieve a porosity of less than 0.05% (in line with EN ISO 13919-1 Class B standard).

1. Formation mechanism of pores in aluminum alloys

1.1 Main pore types

• Hydrogen pores: caused by sudden change in hydrogen solubility (accounting for more than 70%)
• Keyhole collapse pores: caused by dynamic instability of the molten pool
• Surface contamination pores: caused by decomposition of oxide film/oil

1.2 Key influencing factors

Factors	Degree of influence	Controllability
Surface condition	★★★★★	High
Shielding gas	★★★★☆	Medium
Welding parameters	★★★☆☆	High
Material composition	★★☆☆☆	Low

2. Innovative stomatal control technology

2.1 Double-beam swing welding technology
Process Parameters:

• Main beam: 4kW IPG fiber laser
• Auxiliary beam: 1kW high-frequency modulation
• Swing amplitude: 0.4mm (±0.02mm)
• Swing frequency: 200Hz (programmable waveform)

Mechanism of action:

• Extended melt pool life (30% increase)
• Promotes bubble escape (5 times more efficient in escaping)
• Grain refinement (average size< 15 μm)

2.2 High thermal conductivity shielding gas scheme

Helium Mixed Protection:

• Ratio: He75% Ar25%
• Flow rate: 25L/min (double layer protection)

Advantage:

• Thermal conductivity up to 0.15 W/m·K (6 times that of pure argon)
• 40% higher melt pool cooling rate
• Gas Injection Optimization:Angle: 30° inclination
• Nozzle spacing: 8-10mm
• Pressure: 0.3-0.5MPa

2.3 Material pretreatment technology

Laser Cleaning:

• Wavelength: 1064nm
• Energy density: 10J/cm²
• Oxide film removal rate>99%

Vacuum baking:

• Temperature: 150°C
• Time: 2h
• The hydrogen content is reduced to 0.05ml/100g

3. Process parameter optimization matrix

3.1 Recommended parameters for 6061 aluminum alloy

• Laser power: 3.5-4.5kW
• Welding speed: 4-6m/min
• Defocus: +1mm
• Shielding gas: He/Ar mixture (3:1)
• Swing mode: ∞ zigzag track

3.2 Parameter influence rules

• Power increase: porosity first decreases and then increases (optimal range 4kW)
• Speed ​​increase: porosity increases linearly (>8m/min deteriorates sharply)
• Frequency optimization: bubble escape is best at 200Hz

4. Quality inspection and evaluation

4.1 Porosity detection method
X-ray detection: sensitivity 0.1mm

Ultrasonic detection: can measure deep pores

Metallographic analysis: rated according to EN ISO 13919-1

4.2 Typical compliance indicators

Item	Standard value	Measured value
Porosity	<0.1%	0.03-0.05%
Single hole size	<0.2mm	0.05-0.1mm
Pore spacing	>1mm	2-3mm

5. Industrial application cases

5.1 New energy vehicle battery box

• Material: 6082 aluminum alloy
• Process: double beam swing welding

Results:

• Porosity reduced from 2.1% to 0.04%
• Explosion pressure increased to 0.45MPa

5.2 Spacecraft fuel tank

• Standard: NASA-STD-5008
• Technology: vacuum environment laser welding

Performance:

• Leakage rate <1×10⁻⁹Pa·m³/s
• Fatigue life >10⁵ times

Through the combination of dual-beam swing welding, high thermal conductivity gas protection and material pretreatment, the porosity of aluminum alloy laser welding can be stably controlled below 0.05%, fully meeting the needs of high-end applications such as aerospace and new energy vehicles. With the development of online monitoring technology and intelligent control algorithms, aluminum alloy laser welding will break through the final process bottleneck and play a greater role in the field of lightweight manufacturing.

Conclusion

Laser welding has become a core technology of modern manufacturing industry with its advantages of high precision, low thermal impact and efficient automation. It is widely used in automotive batteries, aerospace, microelectronics packaging and medical implants. It can achieve micron-level precision connection, solve the problem of welding dissimilar metals, and significantly improve production efficiency. With the development of blue laser and intelligent control technology, laser welding will continue to promote technological innovation in high-end manufacturing and become an indispensable precision processing solution in the era of Industry 4.0.

 

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The content appearing on this webpage is for informational purposes only. LS makes no representation or warranty of any kind, be it expressed or implied, as to the accuracy, completeness, or validity of the information. Any performance parameters, geometric tolerances, specific design features, quality and types of materials, or processes should not be inferred to represent what will be delivered by third-party suppliers or manufacturers through LS’s network. Buyers seeking quotes for parts are responsible for defining the specific requirements for those parts. Please contact to our for more information.

Team LS

This article was written by various LS contributors. LS is a leading resource on manufacturing with CNC machining, sheet metal fabrication, 3D printing, injection molding,metal stamping and more.

FAQs

1.What is the purpose of laser welding?

The core purpose of laser welding is to achieve high-precision, high-quality metal joins, which instantly melt the material in a tiny area by focusing a high-energy laser beam, creating a weld that is close to the strength of the base metal. Compared with traditional welding, it has the advantages of small heat-affected zone (which can be controlled within 0.1mm), low deformation (<0.05mm) and fast speed (up to 20m/min), especially suitable for fields with strict requirements for precision and reliability, such as aerospace precision components, medical implants, etc.

2.What can you do with a laser welder?

The laser welder can perform a variety of high-value processing tasks: (1) complete the micro-connection of 10μm-level ultra-fine wires (such as chip wire bonding); (2) Realize the welding of dissimilar materials (such as copper-aluminum transition joints); (3) Welding complex space curves (with six-axis robots); (4) Dealing with highly reflective materials (such as gold and copper) that are difficult to weld with traditional processes; (5) Complete the sealing welding in a vacuum or special gas environment (suitable for nuclear industry components).

3.What metals can a laser welder weld?

Modern laser welders can handle the vast majority of industrial metals: (1) stainless steel and carbon steel (welding depth up to 20mm); (2) Aluminum alloy (need to cooperate with swing welding to control the pores); (3) Highly reflective metals (copper/gold needs to use pulsed or blue laser); (4) High-temperature alloy (nickel-based alloy welding strength up to 900MPa); (5) Reactive metal (argon protection is required for titanium alloy welding); (6) Special combinations (e.g., steel-aluminum dissimilar connections) that cover almost all manufacturing needs.

4.What industries use laser welding?

Laser welding has penetrated into the field of high-end manufacturing: (1) new energy vehicles (battery module welding efficiency increased by 5 times); (2) consumer electronics (welding yield of mobile phone internals is 99.9%); (3) Medical devices (vascular stent welding accuracy± 2μm); (4) Aerospace (engine blade welding fatigue life exceeds 100 million times); (5) Energy equipment (nuclear reactor sealing welding leakage rate <10⁻⁹Pa·m³/s) has become a key technology for industrial upgrading.