SS400 mild steel — the most common laser cutting material
SS400 (equivalent to Q235, ASTM A36, S235JR) is the most widely used low-carbon steel in Vietnamese sheet metal fabrication. It’s affordable, easy to process, and available in every thickness from 0.5mm to 100mm+.
With our 6kW fiber laser, Laser Tuan Thinh cuts mild steel SS400 up to 25mm thick — the practical maximum for quality cuts on current fiber laser technology.
Cutting capability by thickness
| Thickness | Cut Speed (m/min) | Assist Gas | Edge Quality | Tolerance |
|---|---|---|---|---|
| 1mm | 30 – 40 | N₂ or Air | Very clean | ±0.1mm |
| 2mm | 18 – 25 | N₂ or Air | Very clean | ±0.1mm |
| 3mm | 10 – 15 | N₂ or O₂ | Clean | ±0.1mm |
| 5mm | 5 – 8 | O₂ | Clean | ±0.15mm |
| 8mm | 2.5 – 4 | O₂ | Good | ±0.15mm |
| 10mm | 1.5 – 2.5 | O₂ | Good | ±0.2mm |
| 12mm | 1.0 – 1.8 | O₂ | Good | ±0.2mm |
| 16mm | 0.6 – 1.0 | O₂ | Acceptable | ±0.3mm |
| 20mm | 0.3 – 0.5 | O₂ | Acceptable | ±0.3mm |
| 25mm | 0.15 – 0.3 | O₂ | Acceptable | ±0.5mm |
Quick rule: Every time you double the thickness, cutting speed decreases by roughly 3–4×.
Oxygen vs nitrogen — which assist gas?
This is the most important decision when cutting mild steel:
| Criteria | Oxygen (O₂) | Nitrogen (N₂) |
|---|---|---|
| Max thickness | 25mm | 8mm |
| Speed (thin steel) | 30% slower | Faster |
| Speed (thick 6mm+) | Faster | Very slow / not feasible |
| Edge color | Black (iron oxide) | Silver-white (no oxide) |
| Needs painting after? | Yes — must grind oxide first | No — clean edge |
| Gas cost | Low | 3–5× more expensive |
| Burr | May occur on thick steel | Less |
When to use oxygen
- Steel ≥ 6mm — nitrogen lacks the energy to pierce through
- Parts will be painted or galvanized after cutting — oxide layer doesn’t matter
- Prioritizing low cost — oxygen is much cheaper than nitrogen
When to use nitrogen
- Thin steel ≤ 5mm requiring clean edges
- Parts that are visible and unpainted — silver-white edges look better
- Welding immediately after cutting — oxide-free edges produce better welds
Reference pricing
| Thickness | Assist Gas | Reference Price (VND/m cut) |
|---|---|---|
| 1mm | Air | 1,500 – 2,500 |
| 2mm | Air | 2,000 – 3,500 |
| 3mm | O₂ | 3,000 – 5,000 |
| 5mm | O₂ | 5,000 – 8,000 |
| 8mm | O₂ | 8,000 – 14,000 |
| 10mm | O₂ | 12,000 – 20,000 |
| 12mm | O₂ | 18,000 – 28,000 |
| 16mm | O₂ | 30,000 – 48,000 |
| 20mm | O₂ | 50,000 – 75,000 |
| 25mm | O₂ | 80,000 – 120,000 |
Processing cost only, material not included. Depends on geometry, quantity, and complexity.
Quick comparison: Mild steel cutting costs ~50% less than stainless steel at the same thickness, and ~60% less than aluminum.
Laser vs plasma vs oxy-fuel for thick steel
Many customers ask: “Should I laser cut or plasma cut 20mm steel?” Here’s a practical comparison:
| Criteria | Fiber Laser 6kW | CNC Plasma | Oxy-fuel |
|---|---|---|---|
| Max thickness | 25mm | 50mm+ | 200mm+ |
| Tolerance | ±0.2–0.5mm | ±0.5–1.0mm | ±1.0–2.0mm |
| Kerf width | 0.2–0.5mm | 2–4mm | 3–6mm |
| Edge quality | Smooth, low burr | Rougher, needs grinding | Rough, needs heavy grinding |
| Smallest hole | Ø1mm | Ø5mm | Ø10mm |
| Speed (10mm) | 1.5 m/min | 2.5 m/min | 0.3 m/min |
| Complex shapes | Excellent | Fair | Poor |
Bottom line:
- ≤ 25mm, precision needed → Laser cutting
- 25–50mm, wider tolerance OK → CNC plasma
- > 50mm or on-site work → Oxy-fuel
Industrial applications by thickness
1–5mm: Enclosures, brackets, panels
- Electrical enclosures and switchboard housings
- Equipment mounting brackets
- Server rack frames
- Motor and pump base plates
6–12mm: Machine frames, structural parts
- CNC machine beds and press frames
- Steel structure gusset plates
- Pipe flanges
- Reinforcement plates for steel frames
12–25mm: Heavy structural, specialty equipment
- Industrial machine bases
- Bridge steel gusset plates
- Wear plates for conveyor systems
- Mining equipment components
Design tips for thick steel
- Minimum hole = 1× thickness — 10mm steel needs holes ≥ Ø10mm for good quality
- Edge distance ≥ 1.5× thickness — Parts near sheet edges will distort from heat
- Avoid internal sharp corners — Use radius R ≥ 1mm to prevent heat concentration
- Holding tabs — Steel ≥ 12mm needs tabs to prevent parts falling through the cutting bed
- Stress relief — Thick steel plates may warp after cutting due to residual stress; heat treatment needed if flatness is critical
Order thick steel laser cutting
We are one of the few shops in Binh Duong that laser cut mild steel up to 25mm using fiber laser — not plasma, not oxy-fuel.
- Max sheet size: 3000 × 1500mm
- Tolerance: ±0.1mm (steel ≤ 8mm), ±0.2mm (8–16mm), ±0.5mm (16–25mm)
- Delivery: From 5 days
- Free shipping in Binh Duong
Send your DXF/DWG file via Zalo or email for a quote within hours.
View our full laser cutting service capabilities or get a quote now.