A comprehensive comparison of laser cutting different metals. Learn how material properties affect cutting parameters, edge quality, and processing considerations.
Introduction
One of the strengths of fiber laser cutting is its ability to process a wide range of metals. Each material behaves differently due to unique physical and optical properties. At Fulei Metal, we cut all common metals and many specialty alloys.
Material Properties That Affect Laser Cutting
Absorptivity
Carbon steel has high absorptivity at 35-40 percent. Stainless steel at 30-35 percent. Aluminum at 5-8 percent. Copper at 2-5 percent. Brass at 3-6 percent.
Thermal Conductivity
Carbon steel at 50 W/mK is moderate. Stainless at 16 W/mK is low. Aluminum at 237 W/mK is very high. Copper at 401 W/mK is extremely high. Brass at 120 W/mK is high.
Reflectivity
Carbon steel and stainless have low reflectivity. Aluminum, copper, and brass have high reflectivity requiring back-reflection protection.
Carbon Steel (Mild Steel)
The easiest and most commonly laser-cut metal. With oxygen, the exothermic reaction enables fast cutting up to 20-25 mm. Oxygen cutting produces slight oxide. Nitrogen cutting produces clean bright edges.
Stainless Steel
Cuts well with nitrogen to preserve corrosion resistance. Speeds range from 6,000 mm/min for 1 mm to 600 mm/min for 10 mm. Nitrogen produces excellent bright, smooth, oxide-free edges. HAZ is small at 0.05-0.15 mm.
Aluminum
Challenging due to high reflectivity and conductivity but manageable with fiber lasers. Nitrogen only (oxygen is dangerous). Speeds from 5,000 mm/min for 1 mm to 500 mm/min for 10 mm. High gas pressure of 14-25 bar essential. Soft surface requires careful handling.
Copper
One of the most challenging metals. Only fiber lasers with back-reflection protection can cut it. Speeds from 3,000 mm/min for 1 mm to 800 mm/min for 3 mm. Maximum thickness 3-5 mm. Higher power improves performance.
Brass
Slightly easier than copper. Nitrogen at 16-22 bar. Speeds from 3,500 mm/min for 1 mm to 1,000 mm/min for 3 mm. Maximum thickness 4-6 mm.
Specialty Materials
Titanium cuts well with nitrogen or argon, never oxygen. Nickel alloys are challenging. Galvanized steel cuts like carbon steel but zinc coating causes dross and fumes.
Conclusion
Different metals respond differently to laser cutting. Understanding these differences is essential for optimal results. At Fulei Metal, our experience cutting all common metals enables us to select the right parameters for each material.
Material Behaviour at the Kerf
Material choice drives the assist gas, the parameters, and what has to happen to the edge before the next operation. This table is the practical version of that chain.
| Material | Cutting behaviour | Assist gas normally used | Watch for |
|---|---|---|---|
| SPCC mild steel | well behaved and the widest process window | oxygen for speed, nitrogen for a clean edge | an oxygen-cut edge carries oxide that must come off before coating |
| SECC galvanized steel | the zinc coating vaporises during cutting | nitrogen preferred | fume extraction is essential; zinc is depleted near the cut edge |
| SUS304 stainless | cuts cleanly and predictably | nitrogen | heat tint, and heat-affected-zone concerns on welded assemblies |
| Aluminium 5052 or 6061 | reflective and highly conductive | nitrogen | batch variation between tempers; dross adherence |
| Copper and brass | strongly reflective | higher peak power with safeguards | confirm with us at RFQ rather than assuming it is available |
Two of these rows have consequences that arrive later. Galvanized edges lose zinc locally, which matters if the part relies on that coating for corrosion protection at the cut boundary. And an oxygen-cut mild steel edge must be cleaned before powder coating — coatings do not adhere reliably to mill scale or oxide.
Frequently Asked Questions
Which assist gas do you use?
Nitrogen as standard for stainless, aluminium and any part that will be welded or coated, and oxygen where speed matters and the edge will be cleaned afterwards. The choice follows what happens next, not habit.
Does cutting damage the corrosion protection on galvanized sheet?
Locally, yes — zinc is vaporised at the kerf. Where the cut edge needs protection we plan finishing accordingly rather than assuming the coating continues to act.
Can you advise on choosing between SPCC and stainless?
Yes, though it depends on the operating environment rather than on cutting. If you tell us where the part will live, the material question usually answers itself.
Questions about a specific part are usually faster to answer against the drawing — send it through the route below.
About these figures. The reference values above come from our own production range; how these materials behave in forming lists the machines and materials behind them, and DFM review explains the adjacent steps that change the result. For your own part, materials we cut is the fastest route to a quote — the earlier we see the drawing, the more of it can still be adjusted without cost. The tolerance context is set out in stainless cutting detail.