Material Weldability Comparison
Comprehensive guide to laser welding characteristics of common materials. Essential reference for material selection and parameter planning.
Weldability Ratings (1-5 Stars)
Carbon Steel
Main Challenges
None significant
Requirements
- • Standard argon shielding
- • Clean surface (minimal prep)
Engineer's Notes
Ideal beginner material. Excellent absorption at 1064nm.
Stainless Steel 304/316
Main Challenges
None significant
Requirements
- • High-purity argon (99.999%)
- • Clean, oxide-free surface
Engineer's Notes
Excellent weldability. Watch for chromium depletion in HAZ.
Aluminum 6061/5052
Main Challenges
High reflectivity (92%) + Oxide layer
Requirements
- • Surface cleaning critical
- • Higher power density
- • Remove oxide immediately before welding
Engineer's Notes
Oxide reformation in <1 hour. Use stainless steel brush only.
Copper
Main Challenges
Extreme reflectivity (95%) + Very high thermal conductivity (398 W/m·K)
Requirements
- • Preheat to 200-300°C
- • Very high power
- • Green laser (515nm) preferred
Engineer's Notes
Fiber lasers struggle. Consider copper coating or surface treatment.
Titanium Ti-6Al-4V
Main Challenges
Highly reactive with oxygen/nitrogen
Requirements
- • High-purity argon (99.999%+)
- • Trailing shield mandatory
- • Back purging for full penetration
- • Clean room preferred
Engineer's Notes
Contamination causes embrittlement. Beautiful welds when done right.
Galvanized Steel
Main Challenges
Zinc vaporization → porosity
Requirements
- • Gap of 0.1-0.2mm for zinc escape
- • Reduced speed
- • Defocus +0.5mm
Engineer's Notes
Zinc boiling point (907°C) < steel melting (1510°C) causes porosity.
Cast Iron
Main Challenges
High crack susceptibility
Requirements
- • Preheat to 300-500°C
- • Nickel-based filler recommended
- • Slow cooling (post-heat)
Engineer's Notes
High carbon content causes hard, crack-prone HAZ. Avoid thermal shock.
Dissimilar Material Welding Compatibility
| Material 1 ↓ / Material 2 → | Carbon Steel | SS | Al | Cu | Ti | Galv. | Cast Iron |
|---|---|---|---|---|---|---|---|
| Carbon Steel | ✅ | ✅ | ❌ | ❌ | ❌ | ⚠️ | ⚠️ |
| Stainless Steel | ✅ | ✅ | ❌ | ⚠️ | ❌ | ✅ | ⚠️ |
| Aluminum | ❌ | ❌ | ✅ | ⚠️ | ❌ | ❌ | ❌ |
| Copper | ❌ | ⚠️ | ⚠️ | ✅ | ❌ | ❌ | ❌ |
| Titanium | ❌ | ❌ | ❌ | ❌ | ✅ | ❌ | ❌ |
| Galvanized | ⚠️ | ✅ | ❌ | ❌ | ❌ | ✅ | ⚠️ |
| Cast Iron | ⚠️ | ⚠️ | ❌ | ❌ | ❌ | ⚠️ | ⚠️ |
Recommended Power by Material & Thickness
| Thickness | Carbon Steel | Stainless Steel | Aluminum | Copper |
|---|---|---|---|---|
| 0.5mm | 0.5-0.8kW | 0.5-0.8kW | 0.8-1.2kW | 2.0-3.0kW |
| 1.0mm | 1.0-1.5kW | 1.0-1.5kW | 1.5-2.0kW | 3.0-4.0kW |
| 2.0mm | 1.5-2.0kW | 1.5-2.0kW | 2.5-3.5kW | 5.0-6.0kW |
| 3.0mm | 2.0-2.5kW | 2.0-2.5kW | 3.5-4.5kW | 7.0-9.0kW |
| 5.0mm | 3.0-4.0kW | 3.0-4.0kW | 5.0-7.0kW | 12+ kW |
* Values for butt joint configuration. Lap joints may require 10-20% more power.
* Speeds assumed: Steel 40-60mm/s, Aluminum 50-70mm/s, Copper 30-50mm/s.
* For thicknesses >5mm, consider multiple passes or hybrid welding.
Practical Selection Guide
For New Projects
- Check material grade: Verify exact alloy designation (e.g., 6061 vs 6063 aluminum)
- Review weldability rating: Start with 4-5 star materials if possible
- Calculate power needs: Use table above as starting point
- Plan surface preparation: Budget time for cleaning (especially aluminum/titanium)
- Test weld first: Always run sample welds to verify parameters
Common Mistakes to Avoid
- Insufficient power for aluminum: Most common error - always use 1.5-2× steel power
- Poor copper surface prep: Oxide layer reforms instantly - weld immediately after cleaning
- No preheat for cast iron: Will crack 100% without 300°C+ preheat
- Inadequate titanium shielding: Any blue/yellow discoloration = contamination = scrap
Quick Decision Tree
Choose carbon steel if: Cost-sensitive, high volume, minimal prep time
Choose stainless steel if: Corrosion resistance needed, aesthetic important
Choose aluminum if: Weight critical, have high power laser (>2kW)
Avoid copper unless: Electrical conductivity essential AND have green laser or >5kW
Choose titanium only if: Aerospace/medical AND can ensure contamination control