Strength of Laser Welds – Testing, Results, and Expert Analysis

Strength of Laser Welds – Testing, Results, and Expert Analysis

Laser welding of metals is gaining increasing popularity in industrial manufacturing, where speed, precision, and weld quality are crucial. In our test, we examined the strength of fillet welds made using the industrial laser welder FANTECH LWG 4.0 EXPERT and performed a detailed macrosection analysis. The results will impress even the most demanding professionals – the laser welds demonstrated exceptional durability and quality, fully meeting the requirements of demanding industrial applications.

What You'll Find in This Article:

Laser Welding and Its Advantages in Industry
How Was the Fillet Weld Strength Test Conducted?
Interpreting the Results Is Clear-Cut
Fillet Weld Macrosections – A Look Inside the Structure
When to Choose Laser Welding for Your Project?
Detailed Photos with Descriptions

Laser Welding and Its Advantages in Industry

Laser welding is a metal-joining method that uses a highly concentrated beam of laser light. This beam delivers energy directly into the weld seam, causing rapid melting of the material followed by solidification. As a result, the joint is extremely precise, clean, and often stronger than the surrounding base material.

Compared to conventional methods like MIG/MAG or TIG welding, laser welding offers several significant advantages:

Precision: Laser enables very narrow and accurate welds, minimizing the heat-affected zone in the surrounding material.
Speed: Higher welding speed results in shorter production times and greater productivity.
Quality: Welds are smooth, uniform, and often require no additional finishing.
Flexibility: The method is suitable for both thin and thicker materials, various metal types, and material combinations.

In practice, this means laser welding can be applied across many industries — automotive, aerospace, engineering, energy, food production, healthcare, and fine metal fabrication.

TEST 1: Weld Analysis on 3 mm Sheet

At a power output of 900 W, welds on thinner sheets were produced with a homogeneous structure and no visible defects.

The penetration was sufficiently deep to ensure the strength and reliability of the joint.

These results confirm that laser welding is also suitable for finer constructions where minimizing thermal impact on surrounding material is crucial.

TEST 2: Weld Analysis on 8 mm Sheet

Even with a greater material thickness, the laser technology maintained the ability to produce a uniform and strong weld.

This is especially important for structures exposed to high loads or vibrations, where any internal defects could lead to failure.

How Was the Fillet Weld Strength Test Conducted?

Material and Equipment Used

For the strength test, S355 steel sheets with a thickness of 6 mm were used.
G3Si wire with a diameter of 1.2 mm served as filler material.
The welds were made using the FANTECH LWG 4.0 EXPERT laser welder with a power of 2000 W.

The following welding parameters were set

Power: 1750 W
Oscillation: 4 mm
Welding speed: 60 cm/min

These parameters were chosen to reflect common practice in component manufacturing, where both joint quality and working speed are essential.

Test Objective

The main goal was to determine whether fillet welds could withstand high tensile forces and meet the requirements for use in demanding industrial applications. We also wanted to verify whether laser technology can provide strength equal to or greater than traditional welding methods.

Tensile Test Results

The tests were conducted in an accredited laboratory. In both cases, the samples fractured outside the weld area, specifically by tearing of the base material.

Measured Values

Sample 1: 549 MPa
Sample 2: 540 MPa

Tensile Test Result of a Fillet Weld Made with the FANTECH LWG 4.0 EXPERT Laser Welder

Photo: Result of the tensile test – Fracture of the base material outside the weld area confirms the high strength of the laser joint.

The Interpretation of the Results Is Clear

The weld strength exceeded the strength of the base material. This confirms that, with properly set parameters, laser welding can produce an exceptionally strong joint.

Macrosection of a Laser Fillet Weld Made with a FANTECH Welder on 3 mm Sheet at 900 W Power

Photo: Macrosection of a fillet weld on a 3 mm steel sheet – homogeneous structure without visible defects at 900 W power.

Macrosections of Fillet Welds – A Look Inside the Structure

To assess the quality of the joints not only in terms of mechanical strength but also in terms of metallurgical structure, macrosections were performed. These provide a detailed view of the internal cohesion and penetration of the weld.

Photo: Macrosection of a laser fillet weld on an 8 mm steel sheet made with a FANTECH welding machine

Photo: Macrosection of a fillet weld on an 8 mm steel sheet – uniform and solid joint even with increased material thickness.

Effect of width and power on penetration depth

Two fillet welds made with different parameters were compared:

Left weld: power 1750 W, width 4 mm
Right weld: power 1400 W, width 2 mm

Interestingly, the right weld achieved a deeper penetration despite the lower power. This is due to the more concentrated energy delivery into the narrower weld, which enables more effective material heating in depth.

Key Findings from the Test

Laser welds can be stronger than the base material.
The technology is suitable for various material thicknesses – from thin sheets to thicker sections.
Weld penetration quality is significantly influenced by weld width and power settings.

When to Choose Laser Welding for Your Project?

Laser welding is the ideal choice when you:

Require high precision and aesthetic quality of the joint.
Need to minimize the heat-affected zone.
Work with demanding materials or metal combinations.
Seek an efficient method for series production.

Live Demonstrations Available at FANTECH Showrooms

We offer interested clients the opportunity to see the FANTECH LWG 4.0 EXPERT laser welder in action. At our showrooms, you can watch live welding demonstrations or consult your specific needs with our sales representative or welding specialist.

Laser Welding = The Inevitable Future

Laser welding proves to be a reliable and versatile method suitable for a wide range of industrial applications. Our tests have shown that with proper parameter settings, it is possible to achieve welds that are stronger than the base material itself.
For companies looking for a technology that combines speed, precision, and quality, laser welding is the logical step forward.