How does travel speed affect weld penetration?

Slower speed = more heat input = deeper penetration, but also wider HAZ and more distortion. Faster speed = less penetration, narrower HAZ, less distortion. Rule of thumb: halving speed increases penetration by ~40-50%, not double. There is an optimal speed range where you get good penetration with acceptable distortion. Too slow can cause excessive spatter and porosity.

What power density is needed for keyhole welding?

Keyhole threshold: approximately 10⁶ W/cm² or 10,000 W/mm². Example: 6kW laser with 0.3mm spot = 6000/(π×0.15²) ≈ 85,000 W/mm² - well into keyhole regime. For conduction welding: <2000 W/mm². Transition zone: 2000-8000 W/mm². Fiber lasers with small spots easily achieve keyhole mode, while defocused beams enable conduction mode when needed.

How do I prevent porosity in laser welds?

Key factors: 1) Stable keyhole - avoid excessive power fluctuations or speed changes. 2) Proper shielding gas coverage - prevents atmospheric contamination. 3) Clean base material - remove oil, oxide, moisture. 4) Appropriate travel speed - too fast causes keyhole instability. 5) Consider wobble/weaving for wider keyholes. 6) Back-purge for reactive materials (stainless, titanium).

Laser Weld Penetration Depth Calculator

⚡ Quick Answer: Welding Mode Thresholds

Conduction: <2000 W/mm² | Transition: 2-8 kW/mm² | Keyhole: >8 kW/mm² → deep penetration

Estimate laser weld penetration depth based on power, speed, and spot size. Determines keyhole vs conduction mode and provides quality recommendations.

Laser Power (W)

Travel Speed (mm/min)

Spot Diameter (mm)

Material Type

Laser Type

Weld Penetration

Enter welding parameters to estimate penetration depth.

Approximate Penetration Depths (Fiber Laser, Steel)

Power	1 m/min	2 m/min	5 m/min	Mode
2 kW	3-4 mm	2-3 mm	1-1.5 mm	Keyhole
4 kW	5-7 mm	4-5 mm	2-3 mm	Keyhole
6 kW	7-10 mm	5-7 mm	3-4 mm	Keyhole
12 kW	12-16 mm	8-12 mm	5-7 mm	Deep Keyhole

Values for mild/carbon steel with 0.3mm spot, nitrogen shielding. Stainless: similar. Aluminum: 10-20% less due to high conductivity.

Frequently Asked Questions

Conduction mode: Power density <2000 W/mm². Wide, shallow weld pool. Heat transfers via conduction. Low aspect ratio (depth:width ≈ 0.5). Good for thin materials, cosmetic welds. Keyhole mode: Power density >8000 W/mm². Creates vapor cavity (keyhole) that allows deep beam penetration. High aspect ratio (depth:width >1). Required for deep penetration and thick materials. Transition mode is between these two.

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Note: Penetration estimates are based on empirical models and typical conditions. Actual penetration varies with material composition, joint configuration, shielding gas, and beam quality. Always validate with test welds and cross-section examination per AWS D17.1 or your applicable standard.